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Ernst Heinrich Weber1795–1878
Weber colour fractions
Weber introduced new methods of measuring sensitivity, establishing perception as an experimental rather than an observational discipline. Working initially with the discrimination of lifted weights, Weber demonstrated that the smallest appreciable difference was a constant fraction of their actual weights. “It appears from my experiments that the smallest difference between two weights which we can distinguish by way of feeling changes in muscle-tension is that difference shown by two weights roughly bearing the relation 39 to 40, i.e. when one is 1/40 heavier than the other.” This was so irrespective of the absolute weights compared. Weber further showed that different fractions resulted from passively held weights, visual judgments of the lengths of lines, and auditory discriminations of pitch. That is, a general law of discrimination was proposed that applied to all modalities but with fractions specific to the judgments involved. Weber did not provide a generalized mathematical description of what we now call Weber’s law; this was left to Fechner. Weber noted that there were clear individual differences in sensitivity, but judgments of a particular individual tended to be constant. He did much more than compare lifted weights. He introduced the use of callipers to measure two-point thresholds on the skin surface and found that sensitivity varied enormously, with greatest sensitivity around the lips and least on the trunk. The magnitude of the thresholds depended on the area of the skin stimulated, which led Weber to introduce the concept of sensory circles - areas on the skin surface that can result in the stimulation of a single peripheral nerve. He developed a method of delayed comparison, varying the interval between presentations of the first and second stimuli: “In this way one can measure and quantitatively express the clarity of the memory for sensations as it decreases from second to second. As we rarely have the opportunity of measuring such mental processes, I commend these experiments to the attention of psychologists”. Temperature and kinesthetic sensitivity were also examined in Weber’s two books on touch De Tactu (1834) and Der Tastsinn (1846). His work represents a distinct shift in the psychology of perception from philosophy towards physiology, from speculation to experimentation, and from qualitative to quantitative approaches. Weber was born in Wittenberg where he studied medicine, moving on to take a post at Leipzig University. Two of his younger brothers, Wilhelm Eduard and Eduard Friedrich, made their marks in physics and physiology, respectively, and all three collaborated on the early studies on touch. Ernst Weber held the chairs of Anatomy and later of Physiology at Leipzig. His portrait is carried in a motif representing a sequence of psychometric functions - the curves relating the detection of stimulus differences to stimulus intensity. He is portrayed twice close to the upper and lower thresholds for discrimination and it is from such curves that the Weber fraction can be determined.
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Native Americans: Removal and Resistance
Native Americans fought on both sides of the revolutionary war. Native Americans risked losing much more of their land and their autonomy at the hands of the colonials, later the Americans, than they did at the hands of the British.
Andrew Jackson was elected president in 1828. Indian Removal was an important part of his agenda. The Cherokees of Georgia were a major target for removal west of the Mississippi, to Indian Country, now Oklahoma.
In 1838, despite strong opposition and protests, were forcibly removed by federal troops. According to our text, 4,000 people died in the march in winter which came to be known as the Trail of Tears.
The Trail of Tears: They Knew it was Wrong
According to Dr. Amy H. Sturgis, History professor, people at the time knew it was wrong, illegal, and unconstitutional. 1/4 to 1/3 of the Cherokee nation people were lost/died.
The argument used to justify the removal was based on lies. It was unconstitutional.
People on both sides knew that the removal was wrong. Davey Crocket, John Quincy Adams, and Ralph Waldo Emerson on the American side. Many Chiefs stated publicly, including writing letters to the president with over 15k signatures saying they did not agree with the removal. It was not the will of the Cherokee nation.
Black Hawk 1767?-1838
Black Hawk
Brittanica Biography
Black Hawk was a Sauk and Fox peoples Chief. He was born at Saukenuk on the Rock River in Western Illinois.
In 1804, after the Louisiana Purchase, Sauk chiefs were persuaded to sign a treaty with the federal government. In 1816 Black Hawk and other Sauk Chiefs signed another treaty they believed would allow them to remain on their lands forever. They had no clear idea what was involved in the signing of the treaty.
. . . the U.S. Army, fired on Black Hawk’s party as they attempted to cross the river (The Mississippi). continuing to fire even as Black Hawk himself waved a white flag of surrender (585).
I told them that the white people had entered our village, burnt our lodges, destroyed our fences, ploughed up our corn, and beat our people: that they brought whisky into our country, made our people drunk, and take from them their horses, guns, and traps; and that I had borne all this injury, without suffering any of my braves to raise a hand against the whites (588).
Petalesharo 1797?-1874
Petalesharo, Skidi Pawnee Chief
Petalesharo means “generous chief” or “man chief.” He was a Pawnee nation chief. They occupied lands in the old Missouri Territory.
Successful in efforts in 1817 and 1820 to prevent captured young women from being sacrificed (Human Sacrifice). This act was written about in newspapers and led to him being sought after for paintings.
Speech of the Pawnee Chief
Known as the speech delivered by “The Pawnee Chief” or “Petalesharo’s Speech.” It is not known who translated the speech or whether it was Petalesharo or another Pawnee chief that delivered it.
The Great Spirit made us all – he made my skin red, and your white; he placed us on this earth, and intended that we should live differently from each other (589).
The speech offers a “separatist” view of religion and culture.
Spare me then, my Father; let me enjoy my country, and pursue the buffalo, and the beaver, and the other wild animals of our country, and I will trade their skins with your people (590).
Ralph Waldo Emerson 1803-1882
Arguably the most important American thinker of the nineteeth century. He had a strong influence on Thoreau and Walt Whitman.
He became active in the abolitionist movement in the 1850s. In April of 1838, writing in his journal he lamented that “I can do nothing. Why shriek?” The next day he wrote a draft of this letter to President Martin Van Buren, who was carrying out Andrew Jackson’s (March 4, 1829 – March 4, 1837) removal policy, which was passed by congress in 1830 and known as the Indian Removal Act.
Letter to Martin Van Buren
Martin Van Buren, 8th President of the U.S.A.
Written on April 23, 1838. The letter was published in May 14, 1838, then again on May 19th and May 25th in difference newspapers.
that out of eighteen thousands souls composing the nation, fifteen thousand six hundred and sixty eight have protested against the so called Treaty (601).
After explaining why he is writing, he asks if the rumors are true.
In the name of God, Sir, we ask you if this be so? (601)
He pleads to end the removal and explains what is at stake if he continues.
You, Sir, will bring down that renowned chair in which you sit into infamy, if your seal is set to this instrument of perfidy, and the name of this nation, hitherto the sweet omen of religion and liberty, will stink to the world (602).
Quick Write
How does Native American removal and resistance connect with our American identity? Why does this matter?
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Difference Between Diagrams and Graphs
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❶As revealed on the image above the chart is a "more complicated" information structure than the regular tree.
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Utilize our Graphs and Pendulums homework help service today! Enter your keyword Search. Home Graphs and Pendulums Homework Help. Understand all about Graphs and Pendulums with Homework Help It is not necessary that physics topics should always be boring. What is the necessity to learn Graphs? But it is relatively easier to understand: Aspects of Graphs Graphs are mainly used to denote the correlation between two variables distance and time.
It states the displacement movement of any object simultaneously with a change in time. This displacement of distance over time states an average speed or velocity. Any altered factor showcases variations in velocity, distance and time in a graph. Any change in velocity is acceleration How is studying Pendulums important? Facet of Pendulums The pendulum moves to and fro on the application of force, exhibiting the seesaw motions of displacement. Gravity wants to pull it down, and the tangent in the string wants to push it either to left or right ultimately creating equilibrium.
The continuous zigzag motion increases velocity showing its angular frequency speed and time period of oscillation. Where does Graphs and Pendulums Collaborate? Projects and assignments regarding pendulum are to detect and record the changes in velocity or the length of thread. The graphdisplays all the variations made by the pendulum. Graphs and Pendulumsdisplay variations of oscillation on using damped or undamped mass.
You can develop graphs based on: The JUNG architecture is developed to support a range of representations of entities and their relations, such as directed and undirected graphs, multi-modal graphs, graphs with parallel edges, and hypergraphs. It offers a system for annotating graphs, entities, and relations with metadata. This helps with the production of analytic tools for intricate information sets that can analyze the relations in between entities in addition to the metadata connected to each entity and relation.
A chart is a particular information structure understood in the computer system science, that is frequently utilized to offer a design of various kind of issues where a set of items relate to each other in some method. Many of the issues resolved with graphs relate to discovering the fastest or longest course. As revealed on the image above the chart is a "more complicated" information structure than the regular tree.
Therefore a chart supports cycles, while the tree does not. In this case each chart is specified by its edges and its vertices. In the majority of the cases, in order to design and fix our issue, we can presume that the vertices are successive numbers beginning with 1, or 0 in case of 0 based varieties, as we will see later on. Its primary style goals are to make it easy to extend and utilize, effective, and, according to its preliminary inspiration: Unlike other chart libraries which enforce the user to very first choose if he desires to deal with directed, undirected, active or not chart, the design provided by Grph is combined in an extremely basic class that supports blended graphs made of directed and undirected easy and active edges.
Graphs are widely-used structure in computer system science and various computer system applications. Graphs indicate to examine and keep metadata, the connections, which provide in information.
Roadway network, which links them, can be represented as a chart and then examined. All graphs are divided into 2 huge groups: The distinction is that edges in directed graphs, called arcs, have an instructions.
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GRAPHS Homework 1. Draw the acquaintanceship graph that represents that Tom and Patricia, Tom and Hope, Tom and Sandy, Tom and Amy, Tom and Marika, Jeff and Patricia, Jeff and Mary, Patricia and Hope, Amy and Hope, Amy and Marika know each other, but none of the other pairs of people listed know each other. Patricia Hope Jeff %(1). Mar 22, · Understand all about Graphs and Pendulums with Homework Help. It is not necessary that physics topics should always be boring. In, we bring you all the exceptional aspects of physics in our Graphs and Pendulums homework help, by our best subject matter specialists in the most innovative way which makes your homework /5().
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Water, food and the environment
Results of the study demonstrate the importance of aquatic resources in the health and nutritional status of rural people in lowland areas of Attapeu Province, Lao PDR. The general status of local livelihoods is quite poor and, in many cases, basic needs for food are not being met. Clinical signs of malnutrition were prevalent in all three communities in both men and women and at all ages. The health status of women and children was significantly worse than men. Local diets consist mainly of rice, supplemented with insufficient amounts of animal proteins, and almost no fats. The typical diet in many households is insufficient in both quality and quantity, leading to low productivity and a marginal livelihood. Traditional eating habits and lack of appropriate information are at least partially responsible.
Key issues
Aquatic resources make up most of the animal protein consumed in terms of frequency and quantity. This is significant given that the over-all diet is protein-deficient.
Rice and cheaper (bulkier) food items are given priority over protein in local diets. Rice is consumed more frequently and in higher quantities than other types of food, providing most of the calories consumed.
Time and resources devoted to acquiring aquatic resources are a substantial part of livelihood strategies. This includes both fishing and foraging activities, making and maintaining gear and processing fish products.
Aquatic resources are a key part of the coping strategy for periods of rice shortage.
Aquatic organisms are often sold and bartered, especially the larger, more valuable organisms and especially when rice is in deficit.
Few coping strategies exist for shortages of aquatic resources. Given their importance in the diet, any shortages will have major impacts on people’s well-being.
Local practices lead to poor nutrition during pregnancy and lactation, leading to poorly nourished children. This has an impact on the rest of the child’s life.
Food security and poverty alleviation strategies must include aquatic resources management.
Community and household factors that affect food behaviour have a huge impact on people’s health and nutritional status. Aquatic resources management needs to include elements of education and public health.
Knowledge about food and nutrition may have been a more useful criterion for determining dietary intake than economically-based characteristics. Community location did not turn out to be a good predictor of nutritional status among adults or children. The ‘remote’ community of Tamoyot showed the lowest rate of adult malnutrition with child malnutrition rates that were midway between the ‘non-remote’ communities.
Developing effective management interventions for isolated parts of such a complex system is likely to have negative impacts on other parts.
Livelihoods of rural people in the lowlands of Attapeu and aquatic resources cannot be easily separated. Of the animal protein sources consumed in rural households, aquatic resources contribute more to local diets than domestic animals or animals hunted in the forest and are used to compensate for shortages of rice. Households that routinely suffer from food insecurity in the form of insufficient rice often depend on wild aquatic resources to compensate for this deficiency. A rich diversity of fish, crustaceans, molluscs, amphibians, reptiles and plants from a range of water bodies play a central role in traditional livelihoods. Though many of these resources are seen to be declining, they are still important.
Both aquatic resources and rice are fundamental in meeting objectives of promoting poverty alleviation through improved health and nutrition, enhancing food security, and increasing productivity. The link between rice production and aquatic resources is inescapable. Because many aquatic resources are seasonal, cyclical and are common property resources, sustainable management will require an integrated approach. Developing effective management interventions for isolated parts of such a complex system are likely to have negative impacts on other parts. Interactions and connections need to be identified and addressed in management strategies that also address the need to maintain the health of the ecosystem. Developing an understanding of ‘connectivity’ between resources will be crucial to sustainable management.
There is huge potential for promoting sustainable livelihoods in the lowland areas of Attapeu Province. Family and village social structure is intact and arable land and natural resources are still relatively abundant. Livelihoods are diversified and adapted to seasonal and environmental changes. Enhancing such diversity will minimize risks, reduce vulnerability and reduce dependence on non-cultured resources. It is important to promote livelihood strategies that include elements of accessibility, diversity and stability, rather than emphasizing rice production potential alone.
People’s participation is a key component of sustainable management of aquatic resources and sustainable development. Because livelihoods in Attapeu are so closely linked to natural resources, local people are the most logical entry point into sustainable management. Because of their daily interaction with these resources, they know the status better than most outsiders and can provide a valuable mechanism for long-term management. This level of participation is only possible when local people have an active role in management. However, people will only be able to consider the long-term perspective required for sustainable management when their immediate needs for health and well-being are met.
The lack of food security is one of the major constraints to enhancing people’s livelihoods in the villages studied. People who have poor diets typically suffer from ill health and are unable to contribute to local development. Many households do not have enough rice to last throughout the year and are constantly coping with shortages. These households are often highly dependent upon natural resources to overcome their rice deficits. Current provincial plans to increase rice production and eradicate poverty may not adequately serve this group and may even increase their vulnerability by reducing the resources upon which they depend.
Any improvements in the health and nutrition status of rural people in Attapeu will have wide reaching impacts and make a significant contribution to poverty alleviation. Cross-sectoral interventions to address the interconnected issues of health and nutrition should emphasize nutritional quality and food behaviour aspects of food security. Health interventions, including awareness-raising, that cover nutritional issues for women and children will also have great impact.
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Major histocompatibility complex
By Levi Clancy for Student Reader on
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The major histocompatibility complex (MHC, or MHC complex) is present in all vertebrates, and is encoded by a group of genes called HLA in humans and H-2 in mice.
Products of these genes are mostly cell surface glycoproteins involved in antigen presentation. MHC molecules must be bound to a peptide (it does not even have to be pathogenic) in order to be brought to the cell surface by the endoplasmic reticulum. The peptide-binding residues within the MHC determine what kinds of peptides it can bind.
While B cells interact with free antigens, T cells interact only with antigens that are associated with a major histocompatibility complex, thus limiting T cells to interaction with antigens at cell surfaces.
Class I MHC genesClass I MHC genes encode a glycoprotein that presents fragments of peptides synthesized inside the cell. If the peptide is foreign, then the cell is killed by CD8 (cytotoxic) T cells; this mechanism is useful for eliminating virally infected cells. Class I MHC molecules encoded by the human A, B & C loci (or murine K & D loci) are classical Class I MHC molecules; other Class I genes encode non-classical Class I MHC molecules. Classical Class I MHC molecules are expressed in almost every cell type, while non-classical Class I MHC molecules are more cell-specific and are expressed in very few cell types.
Class II MHC genesClass II MHC genes encode a glycoprotein expressed primarily by macrophages, dendritic cells, B cells and T cells (all of which are proliferating antigen presenting cells). This glycoprotein presents fragments of peptides floating in the environment to CD4 (helper) T cells. If the peptide is foreign, then the CD4 cell is activated and goes on to help B cells and participate in inflammation. The chains of this glycoprotein are encoded by the DR, DQ and DP gene (IA and IE in mice). Please remember that 'D' refers to murine Class I MHC genes, while DR, DQ and DP refer to human Class II MHC genes. As with Class I, there are other Class II MHC genes (not mentioned) genes which are cell-specific and highly specialized.
Class III MHC genesMostly encode secreted proteins with immunological functions, including inflammation and complement. Class I and Class II MHC genes are structurally similar and flank the Class II loci. Class III MHC genes encode C4, C2 and Factor B (all involved in the complement cascade) as well as inflammatory cytokines (including tumor necrosis factor (TNF)).
Class I major histocompatibility complex
Class I MHC molecules bind peptides and present them to cytotoxic T cells. A mammalian cell can express all Class I MHC alleles (up to six) at a time. Class I MHC molecules contain a 45kD transmembrane glyocoprotein α chain associated noncovalently with a 12kD β2-microglobulin. The three Class I MHC genes -- A, B and C in humans; K, D and L in mice -- are polymorphic and each encode a different α chain (although be clear that each chain contains α1, α2 and α3 subunits). α chains contain α1, α2 and α3 domains; the α3 region contains a cytoplasmic tail that goes through the lipid bilayer and into the cytoplasm. To summarize, the Class I region of HLA contains HLA-A, HLA-B and HLA-C, which each encode different α chains. Lastly, the noncovalently bound β-2 microglobulin is not encoded within the MHC, but is critical for getting the MHC protein to the cell surface.
Between the α1 and α2 regions is the peptide binding groove (aka antigen binding groove), which presents antigenic peptides to CD8 (cytotoxic) T cells. Antigenic peptides -- usually about nine amino acids -- anchor into the groove at both ends via hydrogen bonds; without this anchoring, the Class I MHC glycoprotein is not brought to the cell surface. Longer peptides bulge out in the middle, while shorter peptides are taught. The middle of the peptide makes negligible contact with the MHC molecule, and is instead available for direct T cell receptor contact.
In the absence of β2-microglobulin, Class I MHC molecules are not expressed on the cell surface. A cell that does not express β2-microglobulin will have Class I MHC molecules floating in the cytoplasm but completely absent from the cell surface; if these same cells are transfected with a functional β2-microglobulin gene, then they begin to express Class I MHC molecules on their cell surface. The enzyme papain cleaves Class I MHC molecules near the transmembrane domain, thus releasing just the extracellular portion (α1, α2, α3 and β2-microglobulin).
Class II major histocompatibility complex
Class II MHC molecules bind peptides and present them to helper T cells. Encoded by the centromeric end of HLA, the Class II MHC protein is (under normal conditions) found on macrophages, dendritic cells, B cells and activated T cells; however, in inflamed tissue, other cells can also express Class II MHC proteins. Class II MHC genes encode 32kD α and 27kD β transmembrane chains, and an intracellular invariant and non-polymorphic Ii chain. The α chain consists of α1 and α2 domains; the β chain consists of β1 and β2 domains. Just as with Class I MHC molecules, the α chain and β chain are noncovalently bound transmembrane glycoproteins with a cytoplasmic anchor.
Between the α1 and β1 domains is the peptide-binding cleft. Just as with the Class I cleft, the Class II cleft presents a peptide antigen; however, the Class II cleft binds antigens of at least 13 peptides (sometimes much longer) that are held in place along their backbone (instead of anchored at the ends) by interactions between cleft residues and the amino acids of the antigen. CD4 (helper) T cells recognize antigens presented by the Class II MHC protein.
The Class II region of HLA contains three genes (HLA-DR, HLA-DP and HLA-DQ) which each encode multiple different α and β chains. This allows a single translation of the HLA Class II genes to produce multiple different Class II MHC complexes. HLA-DR encodes three β chains and a single α chain; HLA-DP encodes one each of β1, β2, α1 and α2; HLA-DQ encodes one each of β1, β2, β3, α1 and α2. Please note, however, that α and β chains from different genes never mix; individual MHCs are always all HLA-DP, HLA-DR or HLA-DQ. Also, mice carry just two Class II Genes (IA, or AαAβ, and IE, or EαEβ).
Cell-surface peptide-bound MHCs bind to T Cell Receptors (TCRs). TCRs have a combining site which interacts the the α helices of α1 and α2, as well as the bound peptide. The center of the MHC-bound peptide nestles into a hydrophobic pocket between the CDR3α and CDR3β regions of the TCR. CDRs 1 and 2 of the Vα domain interact with the NH2-terminus of the MHC-bound peptide; CDR2 1 and 2 of the Vβ domain interact with the C-terminus of the MHC-bound peptide, as well as some of the MHC helices.
Peptide binding cleft
The binding of a peptide to an MHC molecule is very stable under physiologic conditions. Thus, most MHC molecules on a cell surface are associated with a peptide. Each cell expresses ∼105 copies of each Class I molecule, with 2,000 different peptides being presented 100 to 4,000 times on each cell.
Class I MHCClass II MHC
Peptide binding cleftBetween α1 and α2, and closed at both ends.Between α1 and β1, and open at both ends.
Bound peptide structure8 to 10 amino acids, with hydrophobic anchors at each end that interact with the MHC molecule and a middle that interacts with the T cell receptor.13 to 18 amino acids, with residues along its length that interact with MHC molecules (no anchors). The T cell receptor interacts along the entire length of the peptide.
Bound peptide infoUsually an endogenous cellular protein that was digested in the cytosol and then migrated to the cisternae of the endoplasmic reticulum. Contains specific residues for binding to a particular MHC molecule.Usually an exogenous protein that is derived from cells that have been phagocytosed or endocytosed. As with Class I MHC molecules, may bind self or non-self proteins (the T cell receptor distinguishes self from non-self).
There are three different Class I MHC molecules -- A, B and C in humans; K, D and L in mice -- which each bind a different kind of peptide; within each gene, each allele delivers more specificity. Class I MHC molecules usually bind hydrophobic nonameric (nine amino acid) peptides, with specificity defined by same or similar amino acids at certain positions. Different alleles encode different peptide binding cleft residues at these positions.
Class II MHC molecules bind longer peptides than Class I MHC molecules, but only the central 13 amino acids actually interact with the molecule. These central 13 amino acids are conserved, meaning that certain patterns will specifically bind to certain Class II MHC molecule alleles. Peptides binding to Class I MHC molecules are bound primarily at their ends, while peptides binding to Class II MHC molecules are hydrogen-bound along their core amino acids (as opposed to being anchored at their ends).
MHC diversity
Class I and Class II MHC genes -- present on Chromosome 6 in humans (Chromosome 17 in mice) -- are polygenic, polymorphic and codominant. Polygenic DNA encodes multiple proteins with similar structure and function. A polymorphic gene has many different alleles which are all common within a population. Codominance means that both alleles of a gene -- the maternal and the paternal copy -- are equally expressed.
Antibodies and T Cell Receptors (TCRs) use mutation, recombination and other techniques to generate diversity. However, MHC Class I and II molecules just use promiscuity to bind the vast population of peptides. Class I and Class II molecules have low specificity, allowing a single molecule to bind many different kinds of peptide. In addition, Class I and Class II genes are highly polymorphic; for some genes there are over 100 common alleles. Within these alleles, the region encoding the peptide binding cleft has the highest variability.
With so many alleles, most individuals are heterozygous for MHC Class I and MHC Class II genes. However, inbred populations sometimes are homozygous for alleles that encode MHCs able to bind no protein. Although rare, this condition drives home the point that MHC diversity is at the population level, not the individual level (unlike with antibodies and TCRs, whose diversity is generated during hematopoiesis).
Class I genes are expressed co-dominantly. This means that all six alleles (three on each chromosome) are expressed together. As a result, a single cell can have up to six different types of Class I MHCs on its surface. Class II genes are expressed only on proliferating antigen-presenting cells (macrophages, dendritic cells, B cells and activated T cells. Because each class II molecule consists of two proteins encoded by two genes, an individual not only has combinations of individual α and β alleles, but also hybrid Class II MHCs contain maternal and paternal α and β chains (heterozygote complementation).
MHC genetics
The major histocompatibility complex is encoded by HLA genes in humans and H-2 genes in mice.
HLA and H-2 genes encoding the MHC itself are classical MHC genes; HLA and H-2 genes which do not encode the MHC are non-classical MHC genes). Non-classical genes are described in the table below, with non-classical genes without important immune functions are marked with a degree symbol.
Although most non-classical genes have mysterious functions, it is suspected that some have MHC-like function.
H-2 genes (the murine MHC-encoding genes)
Gene productsH-2KIAαβIEαβComplementTNF-α & TNF-βH-2DH-2L
HLA genes (the human MHC-encoding genes)
RegionDPDQDRC4, C2 and BFBCA
Gene productsDPαβDQαβDRαβComplementTNF-α & TNF-βHLA-BHLA-CHLA-A
Gene products
Non-Classical GeneMHC ClassProduct
C2, C4a, C4b, Factor BClass IIIComplement proteins.
°GYP21 & GYP21PClass IIISteroid-21-hydroxylases.
°G7a & G7bClass IIIValyl-tRNA synthetase.
°HSPClass IIIHeat-shock protein.
LMP2 & LMP7Class IIProteasome-like subunits.
TAP1 & TAP2Class IIPeptide transporter.
DMα & DMβClass IICatalyzes binding of peptide to MHC; structurally similar to Class II MHC.
TNFα & TNFβClass IIITumor necrosis factors α & β.
Each region is highly polymorphic, meaning that it can have one of many different alleles.
There are several common mouse strains, and for the sake of efficiency their haplotypes (their set of K, IA, IE, S and D alleles) have been compressed into shorthand. For example, H-2k mice have all k alleles, H-2d mice have all d alleles and H-2b mice have all b alleles. Mice obviously have two chromosomes, so a H-2k/k mouse is one whose two chromosomes have both have all k alleles, and a H-2k/b is a heterozygote with one all-k-allele and one all-b-allele chromosome.
Also, note that the alleles of individual regions can be described -- for example, an H-2k/b mouse has Kk and Kb regions. Haplotypes are closely linked and new recombinant haplotypes rarely arise.
The MHC haplotype is responsible for whether a patient accepts an organ transplant as self or rejects it as foreign.
If a patient receives an organ transplant from a donor with a different MHC haplotype (for example, H-2b/b vs H-2k/k) then that organ is rejected as non-self. The only exception is if a heterozygote (for example, H-2b/k) receives an organ homozygous for one of its haplotypes (for example, H-2b/b or H-2k/k) because it recognizes that haplotype as self.
The Class I region is ∼2,000kb long and contains ∼20 genes. In humans, the Class I region is at the telomeric end of the HLA complex. In mice, the Class I region is split in two, with Class II and III genes in the middle. The Class I region contains HLA-A, HLA-B and HLA-B in humans, and H-2K, H-2D and sometimes H-2L in mice. In humans, there is a litany of Class I non-classical proteins: HLA-E, -F and -G; HFE; HLA-J and -X; and MICA, B, C, D and E. In mice, Class I non-classical proteins are encoded in H-2Q, -T and M regions.
Located on the centromeric end of the MHC region, the Class II MHC region is broken into HLA-DR, -DP and -DQ in humans and H-2IA and H-2IE in mice. Each region encodes multiple Class II α and β chains -- for example, HLA-DR encodes as many as four functional β chains. The multiple α and β chains combine, thereby increasing the diversity of Class II MHC molecules. There are also several non-classical Class II genes, all of which have limited polymorphism. Examples of murine non-classical Class II genes are Oα, Oβ, Mα and Mβ; and two human non-classical Class II genes have been identified, DM and DO.
Class III genes are located between Class I and Class II genes, and encode a variety of proteins. Although not encoding proteins directly related to the major histocompatibility complex itself, Class III genes are present in all vertebrates. Mutations in Class III genes frequently lead to disease.
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History Files History Files
Donate add-in
European Kingdoms
Celtic Tribes
MapGraioceli / Garocelli (Gauls)
Small Nav - Indo-Europeans - Celts
FeatureIn general terms, the Romans coined the name 'Gaul' to describe the Celtic tribes of what is now central, northern and eastern France. The Gauls were divided from the Belgae to the north by the Marne and the Seine, and from the Aquitani to the south by the River Garonne, and they also extended into Switzerland, northern Italy, and along the Danube. By the middle of the first century BC, there was a cluster of smaller tribes in the Alpine region of western Switzerland and the French/Italian border. This included the Graioceli, who were located in the upper valley of the Maurienne (in modern France) and close to Alpis Graia (the modern Little St Bernard Pass). They were neighboured to the north by the Veragri and Salassi, to the east by the Insubres, to the south by the Medulli, and to the west by the Allobroges.
Also called the Garocelli by Caesar, the tribe's name is a tough one to break down. Remove the Latin '-i' suffix and the second part of the core name, 'cel', may be *kel(j)o- (?), meaning 'death'. The first part of the name, 'graio' is the main problem with a meaning that has to be approximated. If it is assumed that the 'i' is a softened 'g', then perhaps *-grago- means 'neck'. The tribe may have been 'the neck (throat) killers'. In its English idiom this would be the 'throat cutters'.
As well as occupying Maurienne and Alpis Graia, the tribe could also be found in parts of north-western Piedmont, on the Italian side of the Alps. They commanded an important pass through the mountains, and they made the Romans very aware of the fact by giving them a hard time as they passed through. Apart from that mention by Julius Caesar, however, they do not feature in history again.
58 BC
Despite the death of Orgetorix, the Helvetii decide to go ahead with their planned exodus. Julius Caesar cannot put up with the idea of having such a dangerous force of Celts occupying the more peaceful plains of Gaul, so he force-marches two new legions from Italy to face the threat, although the Ceutrones, Graioceli, and Caturiges attempt to block his passage through the Alps.
Battle of Bibracte Romans
The Roman troops of Julius Caesar prepare to face the Helvetii and their allies at the Battle of Bibracte in 58 BC, outside the oppidum of the Aeduii tribe
As he passes through the territory of the Vocontii to enter that of the Allobroges and then the Segusiavi, groups from several local tribes are joining the Helvetii, including the Latobrigi, Raurici, and Tulingi, making them one of the largest and most powerful forces in all of Gaul. Unfortunately, the Battle of Bibracte between Celts and Romans is a total victory for the latter. The Helvetii are mercilessly crushed and are forced back to their homeland. This act sets in motion a train of events that results in the eventual annexation of all of Gaul into the Roman state.
25 - 15 BC
Augustus determines that the Alpine tribes need to be pacified in order to end their warlike behaviour, alternately attacking or extracting money from Romans who pass through the region, even when they have armies in tow. He wages a steady, determined campaign against them, and in a period of ten years he 'pacifies the Alps all the way from the Adriatic to the Tyrrhenian seas' (written by Augustus himself).
14 BC
Emperor Augustus creates the province of Alpes Maritimae (the maritime, or seaward, Alps). It has its capital at Cemenelum (modern Nice, although this is switched in 297 to Civitas Ebrodunensium, modern Embrun). The history of the Alpine region's population of Celts is now tied to that of the empire.
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Show Summary Details
Page of
date: 23 April 2019
Summary and Keywords
Indigenous languages are at the verge of extinction. For many indigenous communities, saving their languages means protecting one of the last-standing symbols of their cultural identity, a symbol that has survived a history of colonization and that can impact their well-being. If indigenous languages are to survive, language revitalization strategies need to be adopted by indigenous communities and governments. One such strategy is language revitalization planning, where communities and governments are actively engaged in changing the way group members use language. Language revitalization plans are often derived from two theoretical stands, either language reversal theory (which adopts a language-autonomy perspective) or language vitality (which focuses on the factors that favor a linguistic group’s survival).
Language revitalization strategies also involve some form of bilingual education. Bilingual education in indigenous communities allows indigenous children to learn, and hence to gain competency in, both their indigenous language and the mainstream language. Strong forms of bilingualism, as opposed to weak forms of bilingualism, have great potential for nourishing competency in indigenous languages, because they give equal value to the indigenous language and the mainstream language.
Language revitalization strategies also need to consider the collective functions of language, or how groups use their language. Language can be used by groups as a vehicle for cultural knowledge, as a symbol of identity, and as a tool for communicating in formal and informal settings. Strengthening the collective function of indigenous languages is essential to their survival.
In the case of indigenous people, every single step taken to revitalize their languages (language planning, bilingual education, and the collective functions of language) is an affirmation of their continuous existence in the world, upholding their distinctiveness from colonizers. This “collective existential affirmation” of indigenous people may very well be the drive needed to achieve language revival.
Keywords: indigenous people, indigenous languages, language revitalization, language planning in indigenous communities, intergroup communication
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"url": "http://oxfordre.com/communication/view/10.1093/acrefore/9780190228613.001.0001/acrefore-9780190228613-e-471"
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"It is the most lasting, most beautiful, and most enduring form of decoration-
enamel is the eternal art." -Leonardo Da Vinci
Enamel work has been around for centuries in various cultures all over the world back to Greece in the Fourth Century B.C. Although the technique is thousands of years old it seems to be the most misunderstood art medium. This is probably due to the fact that we use the term “enamel” to mean everything from glossy paint to fingernail polish. Vitreous enamel is the term artists use. This means taking fine granules of glass and firing them onto a metal surface. Usually this is done at around 1500 degrees either in a kiln or with a torch.
Vitreous glass enamel comes in a vast amount of colors that can be either opaque or transparent. Clear enamel is called “flux” which is not to be confused with the flux used in soldering metal. The size of the grains have various effects on color. Copper and fine (pure) silver are the most common metals to enamel on, although other metals can be used such as steel which is how most of our appliances are finished in commercial enameling.
There are various techniques that can be utilized in enameling which create different effects and looks. Here are some very basic explanations of some of the most common forms of enameling:
Sifting- This is basicly just what it sounds like. Dry enamel is put in a sifter and sifted over the surface of the metal. Then it is fired onto the metal. This is often the basis for other techniques to be applied.
Cloisonné- This is probably the most well known technique. The name comes from the French word “Cloison” which means cell. Tiny wires of fine silver are formed to make designs or a picture on the surface of the metal. These wires are fired or soldered down. Then the cells are filled with various colors of wet enamel with either a tiny brush or tool. They are then fired in a kiln at around 1500 degrees. This is done for either seconds or minutes. This could be done in one layer or even 20 depending on shading or other design factors. Each layer has to be fired.
Plique-à-jour- Very similar to Cloisonné in the fact that the design is made up of cells of wire. In this technique though there is no background metal. This way the light is able to come through the enamel like a stain glass window. This is probably the most complicated technique of all.
Champlevé- Enamel is fired into recessed areas of the metal. Traditionally this was done by using the metalsmithing technique of chasing and repose. This was done by hammering on the back side of the metal and using gravers to etch details on the front.
Today probably the most common way of using Champleve would be to acid etch a design and then fill the concave areas with enamel. Sometimes only one transparent color is used in this technique. The variations in the hues of the color are affected by the depth of the enamel.
Basse-Taille-This technique is very similar to Champleve in the fact that you are putting enamel in recessed areas of metal. In this technique though the depth is very shallow and is etched or engraved which shows through the transparent enamel.
LIMOGES-This is actually painting with very finely ground enamel that is mixed with some type of oil. Depending on your artistic skills this can be quite difficult. Grisaille enamel uses only black and white enamel.
I have been very privileged to sit under some of the most famous enamelists in the world. I have tried to glean from all of their individual styles and ways of working and make them my own. I am very grateful to the following Enamel Artists for sharing their talents and expertise:
Merry -Lee Rae, Larissa Podgeretz, Sarah Perkins, Ricky Frank, Linda Darty, Coral Shaeffer, Michelle Raney and Judy Stone.
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Online teaching
Get Adobe Flash player .
Geography Terms
Author: Siler Brandy
Description: Match the term with the correct definition, description, or example.
Keywords: Coordinates, Cardinal Directions, Intermediate Directions, Latitude %26 Longitude, Geography, , online teaching
0. Latitude Lines
1. Compass Rose
2. Degrees
3. Correct Format for coordinates
4. Relative Location
5. Relative Location
6. Prime Meridian
7. Latitude Lines
8. Cardinal Directions
9. Tip for finding or providing directions between places
10. Absolute Location
11. Hemisphere
12. Intermediate Directions
13. Longitude Lines
14. Equator
15. Longitude Lines
0. (Latitude #˚, Longitude #˚)
1. The location of an area defined by it%27s relationship to another area
2. units of measure used when finding absolute location ex: 24˚ N
3. The location of an area defined by its exact position on Earth %26 given in coordinates
4. the directions which lie in between the cardinal directions NE, NW, SE, SW
5. 0˚ Latitude starting point for finding latitude
6. run east %26 west but measure distances North %26 South of the Equator
7. also called parallels
8. run north %26 south but measure distances East %26 West of the Prime Meridian
9. You can find AR on a map by looking NE or TX or W of TN.
10. Start with the %22FROM%22 and end with the %22TO%22.
11. 0˚ Longitude starting point for finding longitude
12. also called meridians
13. A design on a map that shows the directions
14. half of a sphere; in geography - half of Earth
15. the four main directions: North, East, South, %26 West
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"url": "http://www.kubbu.com/?s=geoterms"
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UK Radon Awareness Week!
This week the UK Radon Association is running its annual UK Radon Awareness week in partnership with Public Health England (PHE) and BRE Academy, the primary goal being to raise the public’s awareness of radon. The theme for the 2018 campaign is Healthy Living and takes place from 5th to 11th of November 2018.
The campaign sees employers, home owners and health care professionals gain a greater knowledge of the naturally occurring, radioactive gas and the dangerous effects it can have on the human body. Radon is the second leading cause of lung cancer, and an increased awareness of Radon will lead to a reduction in the number of avoidable lung cancer cases claiming lives each year.
So, what is Radon?
Radon is a naturally occurring colourless, odourless, radioactive gas that can affect properties of all types, ages, locations and uses. It is formed by the radioactive decay of the small amounts of Uranium that occur naturally in all rocks and soils.
Radon levels in the air that we breathe outside are very low, but the levels indoors can become much higher. When the Uranium in the soil and rocks decay, the Radon formed permeates the ground into the open air. It is quickly diluted to low concentrations, however, if it rises into a building, it can become trapped and build to dangerous levels.
UK Radon Awareness Week!
What are the risks of Radon exposure?
When the concentration of Radon gas is high, tiny radioactive particles are inhaled and some are deposited in the lungs. The radiation from these particles damage the lung tissue, and over a long period of exposure may cause lung cancer.
The risks are particularly higher for smokers and ex-smokers.
Official statistics estimate that over 1100 people in the UK die every year from lung disease as a result of radon exposure.
In what area is Radon most commonly found?
Although certain parts of the country are believed to be at a greater risk from Radon due to the underlying geology and varying amounts of Uranium present, any property in any location can contain elevated levels. The latest set of indicative maps published by Public Health England (PHE) show that Radon can be found nationwide, UK Radon Map
UK Radon Awareness Week!
But how does Radon enter a building?
The air pressure within a building is usually lower than the pressure in the soil and rocks around the building’s foundation. Radon enters the building through a process referred to as advection. This is where the gas moves from a point of higher pressure (the ground, soil and rocks) to a point of lower pressure (the building). The difference in pressure causes the building to act as a vacuum, drawing Radon in through foundation cracks and other openings. It is at this point that the Radon becomes trapped within the building and where the levels can start to build up.
I’m worried about the Radon Levels in my property – What can I Do?
The only way to know whether elevated levels of Radon are present is to place a detector in the property for a period of time. In a standard domestic property, one detector will be used in the ground floor living room and one in a first floor bedroom. In a commercial property, the number of detectors required generally depends upon the size, layout and use of the building.
The detectors are then analysed in a laboratory to determine the level of radiation they were exposed to and a written report detailing the results will be provided.
UK Radon Awareness Week!
If elevated levels of Radon gas are detected, we are one of the country’s most experience contractors in Radon remediation. Our specialist surveyors will design a system based upon the severity of the problem and the type of construction.
To prevent Radon from entering the property, a specially calibrated fan can be installed to reverse the pressure differential between the ground, soil and rocks and the inside of the property. Alternatively, a sump can be created beneath the building to become a lower point of pressure.
Once any remedial works have been carried out, BCS will always supply a set of radon detectors so testing can be repeated to confirm that the concentration has fallen to an acceptable level.
UK Radon Awareness Week!
Radon in the workplace!
All employers are legally obliged to assess any risks to their staff while at work and this should include potential radon exposure.
In workplaces such as offices, where hazards are generally pretty low, Radon exposure can be the largest occupational health risk.
PHE recommends a five point plan for employers with premises in a Radon Affected Area:
1. Measurement – Test for Radon on the ground floor and occupied basements.
2. Surveillance – Continue monitoring until remedial action is complete.
3. Risk Assessment – Set priorities for action based on Radon levels.
4. Mitigation – Complete remedial action within six months.
5. Maintenance – Conduct periodic testing and routine checks.
BCS Property Projects provide specialist radon testing and mitigation services throughout the entire UK. With our specialist surveyors on hand to help, don’t leave it to chance. If you discover that your building is in a risk area or you just want some advice contact us on 01325 728039 or email
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Just as colours exist in many-stepped gradations produced by the different capacities for light absorption possessed by different types of matter, so are the wavelengths of vowels shaped into tiers of light and shade by the high or low and front or back position of the tongue during the process of articulation. All Indo-European languages exhibit traces, in different degrees of clarity, that, from very early on, the speakers of the original Indo-European mother-tongue used a three-tiered system of vowel gradation to distinguish different forms of verbs, on the one hand, and different nouns derived from one root, on the other. The most faithful representation of this system is to be found in ancient Greek, where diphthongs exist in three grades of strength. The first, the e-grade, is always characterised by the vowel as first element of the diphthong, to which either an or an u is added. In the second, or o-grade, the initial vowel changes to o, while the second element or remains unchanged. The third grade is called zero grade because only the second element of the diphthong is kept, the first being replaced by zero, i.e. nothing. This results in the series of vowel gradations ei – oi – i and eu – ou – u, for example. The so called irregular verbs of English, which change their stem-vowel in the formation of the past tense and past participle, such as drive – drove – driven, take their origin from exactly the same process of gradation. The forms of the verb drive are the English reflection of the Greek gradation ei – oi – i.
Sanskrit too, has a pervasive system of vowel gradation, equally working on the basis of a distinction between three degrees of strength. Since, just as sandhi, the subject of the previous 101 article, this system is no longer productive in Hindi, its workings, originally designed to help the user of the language in associating a certain word with a certain root and therefore meaning, will often confuse the learner of modern Hindi who has no knowledge of the classical language of India. Since it is neither the wish of most Hindi students to acquire a working knowledge of Sanskrit, nor required in order reach a better understanding of commonly occurring Sanskrit forms in Hindi, this article provides a short introduction to the system of vowel gradation of Sanskrit. Readers interested in the finer details of the correspondence between the representation of the Indo-European system of vowel gradation in Greek and Sanskrit are advised to read the article Why are the vowels ए (ē) and ओ (ō) always long? before continuing to the next paragraph of the present article.
The three grades of vowel gradation of Sanskrit are called, from weak to strong, स्वर (svara), गुण (guṇa) and वृद्धि (vṛddhi). स्वर (svara) corresponds to the zero grade of Greek, e.g. the simple vowel इ (i) or उ (u). गुण (guṇa) corresponds to the e-grade of Greek, e.g. the monophthongised Indo-European diphthongs ए (e) and ओ (o). In Sanskrit the o-grade is no longer to be distinguished from the e-grade, since all diphthongs in became ए and all diphthongs in u became ओ. In order to recover something similar to the original three-tiered system of vowel gradation Sanskrit came up with a kind of super-strong grade called वृद्धि (vṛddhi), in which ए (e) is further strengthened to ऐ (ai) and ओ (o) to औ (au). This results in the two series of vowel gradations: इ – ए – ऐ and उ – ओ – औ. In Sanskrit, the vowel ऋ (ṛ) also takes part in gradation. Its three grades are: ऋ (ṛ), अर् (ar) and आर् (ār). Below are a few examples of each of the gradation series as they are found in Hindi words of Sanskrit origin.
The root विद् (vid) means to know. The noun विद्या, knowledge, is based on its zero grade, so is the word विद्वान, which can be either an adjective meaning learned or a noun meaning scholar. The name of the four most ancient Indian sacred scriptures is derived from the गुण (guṇa) grade of the same root: वेद (veda). Something that pertains to the Vedas is called वैदिक (vaidik) and based on the वृद्धि (vṛddhi) of the root विद् (vid). Note that the common suffix -इक (-ika) always causes the root to appear in its strongest grade.
The root भुज् (bhuj) means to eat or enjoy. Its past passive participle, which uses the suffix -त (-ta) and always has causes the zero grade of the root, is भुक्त (bhukta), meaning eaten. Using another suffix the noun भुक्ति (bhukti), enjoyment, is formed, equally on the zero grade of the root. In the word for meal the same root appears in the गुण (guṇa) grade: भोजन (bhojana). A word in which the root भुज् (bhuj) appears in the strongest grade is not to be found in Hindi, but in the adjective भौम (bhauma), pertaining to the earth, there is an example of the वृद्धि (vṛddhi) of the vowel ऊ (ū) of the noun भूमि (bhūmi), meaning the earth.
The most common root containing the vowel ऋ (ṛ) is without doubt कृ (kṛ), which means to make. In the past passive participle the root appears again in the zero degree: कृत (kṛta), done, performed or made. The adverb कृते (kṛte), on behalf of, equally uses the weakest form of the root. In the well known noun कर्म (karma), deed or action, the same root appears in the गुण (guṇa) grade. The वृद्धि (vṛddhi) grade is found in the common noun कारण (kāraṇa), meaning reason or cause.
Silvio Zinsstag,
teacher for ancient languages
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Explorer 1
po_Explorer1Explorer 1 was the first satellite of the United States, launched as part of its participation in the International Geophysical Year. The mission followed the first two satellites the previous year; the Soviet Union’s Sputnik 1 and 2, beginning the Cold War Space Race between the two nations.
Explorer 1 was given Satellite Catalog Number 4, and the Harvard designation 1958 Alpha 1, the forerunner to the modern International Designator.
Explorer 1 was designed and built by the California Institute of Technology’s JPL under the direction of Dr. William H. Pickering. It was the second satellite to carry a mission payload (Sputnik 2 was the first).
The total weight of the satellite was 13.37 kilograms (30.80 lb), of which 8.3 kg (18.3 lb) were instrumentation. In comparison the first Soviet satellite Sputnik 1 weighed 83.6 kg (184 lb). The instrument section at the front end of the satellite and the empty scaled-down fourth-stage rocket casing orbited as a single unit, spinning around its long axis at 750 revolutions per minute.
Data from the scientific instruments was transmitted to the ground by two antennas. A 60 milliwatt transmitter fed a dipole antenna consisting of two fiberglass slot antennas in the body of the satellite operating on 108.03 MHz, and four flexible whips forming a turnstile antenna were fed by a 10 milliwatt transmitter operating on 108.00 MHz.
Because of the limited space available and the requirements for low weight, the payload instrumentation was designed and built with simplicity and high reliability in mind, using transistor electronics, consisting of both germanium and silicon devices. This was a very early time frame in the development of transistor technology, and was the first documented use of transistors in the U.S. Earth satellite program. A total of 29 transistors were used in Explorer 1, plus additional ones in the Army’s micrometeorite amplifier. Electrical power was provided by mercury chemical batteries that made up approximately 40 percent of the payload weight.
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Tabling a bill means that it is placed on a table for discussion?
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What is a table?
A piece of furniture that has four legs and a plate like structureon top of it. Or it is a graph you can put values and comments into.
What effect does tabling a bill in committee have?
The effect of a tabling a bill in committee enables the members todiscuss the bill. It is important for the bill to have a person whoproposes it and the second you who seconds it.
What do the periods mean on the periodic table?
The periods mean the number of lines there are on the periodic table of elements. For example: Hydrogen is in period 1 Iron is in Period Four The periodic table includes ___ _______ periods. Answer:
What does Hg on the periodic table mean?
Hg is the symbol for Mercury It comes from the Latin word hydrargyrum no its not its the symbol for hydrogen and it comes from the Irish word hydrargyrum
What Does Ga Mean on A Periodic Table?
\n. \n. \nGa on the periodic table means Gallium\n. \n[MORE INFO...]\n. \nMass number is 70\nAtomic number is 31\n. \n=p
What does it mean when a bill is 'tabled'?
In U.S. parliamentary procedure, it means that the deliberative body has ended discussion of a resolution In non-U.S. parliamentary procedure it means that the body has taken up discussion of a resolution.
What is tables?
In relational databases and flat file databases, a table is a set of data elements (values) that is organized using a model of vertical columns (which are identified by their name) and horizontal rows. A table has a specified number of columns, but can have any number of rows [ citation needed ] . ( Full Answer )
What is a round table discussion?
An open discussion where everybody is on an equal footing. Nobody is at the head of the table; you're all peers. The implication is that everyone has an equal voice and that you can speak your mind freely on the subject.
When did chlorine get placed in the periodic table?
1806 was the date of first recognition of chlorine as an element. Chlorine was placed in all of the first three attempts at periodic classification -- Newlands in 1864, Mendeleev and Lothar Meyer in 1869. There was really no such thing as a 'periodic table' before 1869.
What is tabling a bill?
means that the vote on it is simply adjourned until a later time. It comes from the concept that the bill is put back on the table to await future action instead of being voted on and moved to the next appropriate step in the legislative process
Why is thallium placed on the periodic table?
Thallium is placed on the periodic table because all elements are put there.. If you meant where is thallium placed it is element 81, group 13, period 6.
How are elements placed in the periodic table?
Elements are arranged into rows in order of increasing mass, so that elements with similar properties were in the same column. They are organized by type, such as nonmetals, metals, and metalloids, and solids, liquid, gas, or not found in nature.
What exactly is tabling a bill?
What is the meaning of table appointments in table settings?
The Table Appointments Include any Item Used to Set a Table; Tablecloth, Place mats, Dinnerware, Glassware, Flatware and Centrepiece ---------------------------------------------------------- Table appointments are implements used for dining, which consist of linen, silverware, dinnerware, glas ( Full Answer )
What does it mean when a bill is laid on the table?
It is to "kill" a bill that was not accepeted by a committee in congress. More than 90% of proposed bills are tabled. After the bill has been "tabled", the full House or Senate can override committee decisions (but this rarely happens).
Where are the metals placed in the periodic table?
All of the metals on the periodic table are on the left side. Your periodic table probably has what looks like a broken diagonal line running around the middle. Everything to the left of this line (except hydrogen) is a metal.
How was helium placed in the periodic table?
It comes second because it has the second lowest relative atomic mass (2). . The reason it is on the right hand side instead of the left is because it is a noble gas and has a full outer shell of electrons.
What does table a motion mean?
In British English, to table a motion, means to bring up a motion for debate. In American English, it means to postpone a motion. Opposites!
What does table mean in math terms?
In math a table is a chart. For example times table is a chart that shows all the multiples of the numbers on the chart. 1 2 3 4 X One. 1 2 3 4 X two. 2 4 6 8 X three. 3 6 9 12 X four. 4 8 12. 16.
What CD was set a place at your table on?
Justin Bieber singing an original song in *STEREO* written by Jake Leiske and produced by Jay Riehl and recorded at the swamp recording studio located near Gadshill Ontario, just outside of Stratford Ontario. The CD is called "Set a Place at Your Table". The song was produced for a CD to raise money ( Full Answer )
What does tables mean?
A table is a flat-topped piece of furniture used for dining or other activities. A table is also a form of data display containing elements list in columns and rows. The verb "to table" in legislative terms has different meanings in US and world parliamentary use. The primary use of tabling outsid ( Full Answer )
Where the dot on pool table is placed?
The only dot typically applied to a pool table is for the rack spot. This spot is located where the foot line and center line cross. The foot line is an imaginary line connecting the 2nd diamond from the end where the balls are racked. The center line is the imaginary line connecting the center diam ( Full Answer )
Why is radium placed on the periodic table?
because who ever put it there wanted it on the periodic table. i mean no one really knows but its obvious that that old person wanted it in the periodic table cause he thought it would balance it out.... i really don't know i just guess lol hahahahaha but i bet you read this any ways.
What is the meaning of the pow-mia table?
The POW/MIA table is symbolic of members of the armed forces who have become prisoners of war in foreign countries as well as those who are missing and unaccounted for. There 2 different versions of the table: one place setting, and up to 6 or even more. The table with only one place setting is ( Full Answer )
What place the table tennis started?
The game of table tennis has its roots in lawn tennis. When lawn tennis became very popular in the 1870s & 1880s, game makers tried to emulate its' success by developing indoor versions of the game. David Foster of England introduced the first action game of tennis on a table in 1890.
What do the numbers on a periodic table mean?
At the very least, the atomic number and atomic weight of each element will be displayed on a periodic table. The atomic number is the number of protons in the nuclei of the atoms of a given element. The number of protons identifies an element, i.e. each element has its own unique atomic number. The ( Full Answer )
What does H2SO4 mean on the periodic table?
The chemical compound H 2 SO 4 is not on the Periodic Table as it is a compound not an element. However, it is made up of three elements: Hydrogen, Sulphur and Oxygen. In one molecule of this compound there are 7 atoms: 2 Hydrogen atoms, 1 Sulphur atom and 4 Oxygen atoms. The common name for H 2 SO ( Full Answer )
What does group mean in a periodic table?
The group number is the number of electrons in the outer shell of the element. They are columns that move along from left to right, 1 to 18, increasing. So elements in group one will have one electron in its outer shell, and so on. Note: electrons in the outer shell of an element are called vale ( Full Answer )
Who did Macbeth lay a place for at the table?
Nobody. He was the King, not a kitchen wench. A place was laid at the table for Banquo, but of course it was. Do you think Macbeth could go to the kitchen staff and say, "Uh, don't bother setting a place for Banquo since he's going to be dead by suppertime. Not that I know anything about it. How cou ( Full Answer )
Where is the best place to buy a Stiga Table Tennis table?
Many sporting goods stores carry Stiga Table Tennis tables. You can also often find them in general merchandise or discount stores like Wal-Mart. They are sold in nearly 100 countries around the world.
Where do you place the spot on a pool table?
The spot, referred to as the foot spot, is placed at the intersection of two imaginary lines. The first is the line in the center of the table that runs the length of the table. The second is an imaginary line connecting the second diamonds from the end of the table.
How are isotopes placed in the periodic table?
Isotopes and their prevalence are not shown on the periodic table. Instead, the atomic weight shown for each element is an average of the atomic weights of all naturally-occurring isotopes (calculated from percentages occurring on Earth).
Where are the actinides placed in the periodic table?
The actinide series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. There are two rows below the periodic table, the first row is lanthanides and the second row is actinides.
What does table it mean?
It means to delay making a decision on a matter- leaving it on thetable, rather than acting on it.
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Truman 's Choice Was A Good One
989 Words Apr 5th, 2016 4 Pages
On August 6, 1945, a bomb with the force of 20,000 tons of TNT, was dropped on the Japanese city of Hiroshima. Three days later a similar bomb was dropped on the city Nagasaki. Both cities were effectively eradicated and so was there people. Six days after that, Japan surrendered, thus ending World War II. Americans supported the action of Truman, that is until they saw the images of the destructive power of the bomb. The horrific images showing the victims of radiation and of burns that are caused by the force of the sun. As the Christian Century writes “What the use of poison gas did to the reputation of Germany in World war I, the use of the atomic bomb has done for the reputation of the United States in World War II.” The people of America began to question is Truman’s choice was a good one. Could have there been a different way to end the war without using Nuclear force?
After six years of war, Germany finally surrendered. This did not mean that Japan would too. Both countries ultimately entered the war for different reasons. Germany did not because other countries declared war on it because of their imperialism in Europe. Japan entered the war because they saw a opportunity to acquire land in the Pacific and jumped on it, even if it meant war. So when Germany surrendered, it did not really affect Japan 's plan. They still wanted land and continued to fight for it.
Truman only learned of the bomb when he became president. It had only recently been tested and found…
Open Document
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You are here
Plant Draft 2
Submitted by lgorman on Tue, 04/24/2018 - 11:49
In conclusion, they discovered that mechanisms rice plants use to grow adventitious roots mostly involve light signals to stimulate growth, while gravity was a small factor. They found the root growth had a dosage dependent relationship with all colors of light, with red light having the most efficient effect. These plants use light as the most important signal because when there is less light, the plant is probably submerged and it needs to obtain more oxygen. Using this discovery, they proposed that plants monitor oxygen availability by sensing light.
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Dinosaurs are starting to look less and less like they were portrayed decades ago. The fossil of Sciurumimus albersdoerferi, which lived around 150 million years ago, is the first evidence of feathered theropod dinosaurs that are not closely related to birds.
Theropods are bipedal, mostly carnivorous dinosaurs. In recent years, scientists have discovered that many extinct theropods had feathers but feathering had only been found in theropods that are classified as coelurosaurs, a diverse group including animals like T. rex and birds.
Sciurumimus is identified as a megalosaur, not a coelurosaur and is the first exception to this rule. The new species also sits deep within the evolutionary tree of theropods, much more so than coelurosaurs, meaning that the species that stem from Sciurumimus are likely to have similar characteristics.
The fossil, which is of a baby Sciurumimus, was found in the limestones of northern Bavaria and preserves remains of a filamentous plumage, indicating that the whole body was covered with feathers. The genus name of Sciurumimus albersdoerferi refers to the scientific name of the tree squirrels, Sciurus, and means "squirrel-mimic"—referring to the especially bushy tail of the animal. The species name honors the private collector who made the specimen available for scientific study.
"All of the feathered predatory dinosaurs known so far represent close relatives of birds," said palaeontologist Oliver Rauhut, of the Bayerische Staatssammlung für Paläontologie und Geologie. "Sciurumimus is much more basal within the dinosaur family tree and thus indicates that all predatory dinosaurs had feathers."
Skeleton of Sciurumimus as found on a limestone slab. © H. Tischlinger/Jura Museum Eichstätt
"Under ultraviolet light, remains of the skin and feathers show up as luminous patches around the skeleton," said co-author Helmut Tischlinger, from the Jura Museum Eichstatt.
Sciurumimus is not only remarkable for its feathers. The skeleton, which represents the most complete predatory dinosaur ever found in Europe, allows a rare glimpse at a young dinosaur. Apart from other known juvenile features, such as large eyes, the new find also confirmed other hypotheses.
"It has been suggested for some time that the lifestyle of predatory dinosaurs changed considerably during their growth," Rauhut said. "Sciurumimus shows a remarkable difference to adult megalosaurs in the dentition, which clearly indicates that it had a different diet."
Adult megalosaurs reached about 20 feet in length and often weighed more than a ton. They were active predators, which probably also hunted other large dinosaurs. The juvenile specimen of Sciurumimus, which was only about 28 inches in length, probably hunted insects and other small prey, as evidenced by the slender, pointed teeth in the tip of the jaws.
"Everything we find these days shows just how deep in the family tree many characteristics of modern birds go, and just how bird-like these animals were," Norell said. "At this point it will surprise no one if feather like structures were present in the ancestors of all dinosaurs."
Published in the Proceedings of the National Academy of Sciences.
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Scientists discover Earth's youngest banded iron formation in western China
Credit: Zhiquan Li
The Early Cambrian is known for the rise of animals, so the level of oxygen in seawater should have been closer to near modern levels. "This is important as the availability of oxygen has long been thought to be a handbrake on the evolution of complex life, and one that should have been alleviated by the Early Cambrian," says Leslie Robbins, a PhD candidate in Konhauser's lab and a co-author on the paper.
"Future studies will aim to quantify the full extent of these Cambrian banded iron formations in China and whether similar deposits can be found elsewhere," says Kurt Konhauser.
The paper, "Earth's youngest banded iron formation implies ferruginous conditions in the Early Cambrian ocean," was published in Scientific Reports (doi: 10.103841598-018-28187-2).
Media Contact
Katie Willis
[email protected]
<h4>Original Source</h4>
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Skip to main content
The built environment
The built environment
There are strong links between the environment and health. The places in which people live, work and socialise and the connections between these spaces all influence physical and mental wellbeing. The built environment includes the places where we live, work and spend our leisure time. All of these shape the social, economic and environmental conditions on which good health is dependent. The built environment can contribute positively or negatively towards health.
How does the built environment affect health?
Housing and other buildings
We spend most of our time indoors. For good health, people require well-designed homes, workplaces, schools and other buildings that are dry, warm, insulated and spacious enough for their needs. Lack of access to and the poor design of homes, poor air quality, dampness, infestation, overcrowding, noise, and lighting can all contribute to poor health. Adaptations to homes may also be necessary for people with particular needs.
The neighbourhood where we live also impacts on our health. Street environments which appear safe and attractive can encourage walking and cycling in preference to car travel. This could increase physical activity and reduce air and noise pollution. Pleasant places encourage people to spend time outside, so providing opportunities for exercise, social interaction and recreation.
Green spaces have always been used as areas for relaxation and places for people to meet and rest. Evidence suggests that exposure to green spaces can improve mental and physical wellbeing and stimulate social interaction.
Safe street environments encourage social interaction and reduce the risk of injuries to pedestrians. They also encourage children to walk to school and play outside, building healthy physical activity habits for life. Increased physical activity, including cycling, also contributes positively to good mental health.
Everyone relies on the transport system to access services which enable them to carry out the activities necessary for everyday life. The transport system provides access to employment, education, healthcare, shops and leisure, as well as allowing social activity. An efficient, safe transport system is therefore critical to health and wellbeing.
Transport planning can enhance health by providing accessible and safe foot and cycleways, good public transport links and improving access to green spaces and other amenities. Making healthy choices the easy choices can encourage people to change their behaviour to increase their physical activity levels and help them maintain a healthy weight. You can find further information on the transport policy page.
Air pollution
Heavy car use and large amounts of traffic cause air pollution. A high level of air pollution increases cases of asthma. Long-term exposure to air pollution increases the risk of death from cardiovascular and respiratory causes and lung cancer.
Travelling on foot, by bicycle or on public transport decreases overall car use. This has a beneficial effect on air pollution which over time could lead to a decrease in respiratory illness. Further information is available on the air quality page.
Any development of a built environment can have an impact on health. There is an opportunity for how new development and the associated transport infrastructure is designed and planned in South Gloucestershire to contribute positively to the health and wellbeing of future residents.
Planning for large-scale new developments allows us to build in healthy development principles such as increased access to green space, opportunities for physical activity, appropriate transport infrastructure to address air quality issues and high-quality homes and neighbourhoods which have good access to local services and facilities. Spatial and transport planning gives us the chance to improve the health of future generations by making the right development and infrastructure decisions now. You can find out further information in the planning section.
How are we tackling this?
South Gloucestershire Council is working hard to develop good connections between public health, the built and natural environment and how we plan and deliver the new homes, jobs and transport infrastructure.
The Public Health, Planning and Transport teams are working together to use public health evidence to support how we can deliver sustainable new communities and ensure proposed planning and transportation policy and actions deliver good health outcomes for all.
Is there anything wrong with this page?
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Bible Study
The Importance of a Sound Biblical ChronologyAnswers
This lesson examines the order of events in the Old Testament leading up to the birth of Christ. Having a sound knowledge of these events, and the order in which they occurred, provides a solid foundation for our overall understanding of the Bible and God's eternal plan for mankind.
Similarly, as we begin to get deeper into our study of Genesis, it is necessary that we have a good understanding of the order of these events and that we are aware of the controversies surrounding Biblical Chronology. One additional thing that will help us in this understanding is having some knowledge about world history and the events going on outside of the biblical story as well.
Many believe the Old Testament is mostly—if not all—fiction, and since the vast majority of the Old Testament was written long after the actual time of the events, they believe that the events themselves were primarily "created" in order to teach a moral lesson, or to explain in some way something previously not understood. Our task as believers is to prove otherwise. We can best do this by tying together events in world history with an understanding of cultures, nations, languages, and customs and the archaeology unearthed thus far.
Let’s begin this task by considering the following questions:
1. Define the Usher Chronology, what are its weaknesses and strengths?
1. ANSWER: Bishop Usher from Ireland constructed a timeline, a chronology of Biblical events, working backward through time to determine how old the earth is, e.g., what day and date it was created, when Noah's flood occurred, etc.. He concluded that God began creation on a Sunday evening just after sunset, and that the Creation occurred in 4004 BC. From there he built a chronology of biblical events leading up the birth of Christ. The Chronology was held in high regard until the late 1800s when mainstream theologians began to realize that there were many errors in the chronology, which put it at odds with historical evidence.
2. Current history can easily document a period of how many years back in time?
1. ANSWER: History from 6,000 BC to the present is well documented.
3. What is the Göbekli Tepe?
1. ANSWER: It is a temple discovered in Turkey in 2008. Considered to be 12,000 years old, it clearly predates any flood date provided by Usher.
4. What is the significance of the Tel Dan Stele and the Mesha Stele?
1. ANSWER: The Mesha Stele is the most extensive inscription ever recovered that refers to the kingdom of Israel, and it is the earliest record of the House of David and the Kingdom of Judah. The Tel Dan Stele, discovered in 1993-94 is the first record of David as King outside of the Bible.
5. Now let’s practice, using a combination of world history and the biblical text, to establish a date. Read Luke 3:1-23. From this passage and our knowledge of Roman history, see if you can calculate the year of Christ's birth.
1. ANSWER: History tells us that Caesar Augustus died in 14 AD and that Tiberius then became emperor. Therefore, if Christ was 30 in the 15th year of Tiberius’ reign, then Christ would have been 30 in 29 AD (i.e., 14 AD plus 15 years of Tiberius’ reign). This would mean that Christ was born in 1 BC. However, the Greek translation of Luke’s text is more accurately read as "30-something" (vs. "30"), so his likely birth would have probably occurred closer to 6 BC.
6. Read 1 Kings 6:1. What date was the Temple built, and when did Solomon's reign begin?
1. ANSWER: The Temple was built 480 years after the Exodus and in the fourth year of Solomon’s reign. So, in order to establish a date for this, we need to have a date for the Exodus. Two dates for the Exodus are proposed, since no one has determined with precise certainty when it occurred. The "early" date for the Exodus is 1446 BC, and the "late" date is 1250 BC. I personally hold to the early date. However, using either of these two Exodus dates, we can arrive at the Temple being built in 966 BC. Interestingly, the late date approach arrives at approximately the same date, however, it uses 300 years, not 480 years. The late date approach bases this on the fact that they believe the 480 is symbolic of 40 generations, and that an actual generation was 25 years old. Thus, 300 years after the Exodus, the Temple would be built, based on a 1250 BC Exodus. Again, both agree that the Temple was built in 966 BC. Solomon's reign then is from 4 years prior, 970 BC (to 930 BC, as he ruled for forty years).
7. Using 970 BC as the beginning of Solomon's reign, we can then establish dates for the reign and deaths of Saul and David. What would they be?
1. ANSWER: Saul reigned for 40 years, from 1050 BC to 1010 BC, and then he died. David followed Saul and reigned for 40 years--38 of them over a united Israel--and then he died, thus reigning from 1010 BC to 970 BC
8. Continuing back from the reign of Saul covers a period of time referred to as the Time of the Judges, plus additionally the period of time of the occupation led by Joshua, which was preceded further by the forty years of wilderness wanderings--which began with the Exodus. So, what was the length of time from God's promise to Abraham until the time of the Exodus and the giving of the Law? Read Exodus 12:40-41 and Galatians 3:16-17.
1. ANSWER: We can observe from these two passages that the time from Abraham's promise to the giving of the Law was 430 years. If the Exodus occurred in 1446 BC, then Abraham's promise came in 1776 BC, when he was 75 years old (Hebrews 6:15), thus establishing his year of birth as 1851 BC.
9. 3000 BC is recognized as the beginning of written records. What role did the Sumerian and Egyptian people play in this process?
1. ANSWER: Almost simultaneously, even though they were geographically widely separated, the Sumerians invented cuneiform writing, and the Egyptians invented Hieroglyphics.
10. The Tower of Babel event is dated at 3600 BC or earlier. Prior to the Tower of Babel, date uncertain, the Great Flood ended, and Noah and his family descended the Ark. Which of his three sons are the Semitic people descended from? See Genesis 10:21-32.
1. ANSWER: The Semitic people, the Semites, descended from Shem.
11. Order the following events in their proper order, from the earliest to the most recent:
• Solomon builds the Temple
• Cain slays Abel
• Methuselah dies
• Joshua brings down the walls of Jericho
• Seth is born
• The Towel of Babel
• David is King
• Babylon destroys the Temple
• Jews are enslaved in Egypt
• Noah and the Flood
• Christ is born
1. Cain slays Abel
2. Seth is born
3. Methuselah dies
4. Noah and the Flood
5. The Tower of Babel
6. Jews enslaved in Egypt
7. Joshua brings down the walls of Jericho
8. David is King
9. Solomon builds the Temple
10. Babylon destroys the Temple
11. Christ is born
In summary, understanding the proper order of the events in biblical history and tying those events to historical dates is possible using a combination of archaeology, the biblical text, and historical "synchronisms" (i.e., tying in the historical events and evidences that confirm the Bible). As students of the Bible, we need to have a fundamental understanding of these events, their order, as well as the evidences that exist outside of the biblical text which point to the accuracy of God’s Holy Word.
Praising God for your continued faithfulness in studying His Holy Word.
In Christ,
[PDF Version]
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Direct read after write
From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Direct read after write is a procedure that compares data recorded onto a medium against the source. A typical example would CD burning software which reads a CD-ROM once it has been burned onto, effectively ensuring that data written is the same as the data it was copied from.
External links[edit]
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How to Design a Bio-intensive Garden
Double-digging is an important part of bio-intensive gardening.
Bio-intensive gardening is a system of producing food that concentrates on harvesting the largest amount of crops using the least amount of resources. These gardens use less land, water, fertilizer and even human effort than other, traditional methods and often produce many times as many vegetables. A bio-intensive garden is a connected collection of systems, based on the way the plants are laid out and the plants that you choose to grow. Each of these gardens is an individual effort, and there is no perfect bio-intensive design, but every one of them relies on a set of principles focusing on efficient food production.
Purchase or build a compost bin, or set up a system of compost heaps. Bio-intense gardens need a lot of nutrients, and compost is a free and simple way to amend the soil while feeding your crops. Turn every scrap of dead plant material and kitchen waste into compost, and you'll have a continuous supply of free plant food.
Lay out your garden outline in a sunny area of the yard that gets at least six hours of sunlight each day. Stay away from trees or outbuildings that may cast shade in early morning or late afternoon. If you have a chain-link fence around your property, place the garden against the fence to take advantage of the available vine support system.
Double-dig the entire garden plot to give the soil aeration and remove any compacting that may have happened. Do this by digging a 12-inch-wide trench that measures 12 inches deep for the entire length of the garden. Place the soil in a wheelbarrow or on a tarp. Dig down another 12 inches and turn over this second foot of soil. Dig a second trench right next to the first one. Pile the soil from the second trench into the first one, mixing in a large amount of well-rotted compost. Dig and turn over the bottom 12 inches of the second trench. Continue on digging trenches in a striped pattern until you reach the end of the garden. Fill in the top of the last trench with the soil you took from the first on, mixed with compost. Do not stand on this soil after you have finished double-digging.
Select your seeds with an eye to efficiency. Choose compact plants if they will produce the same amount of food as full-sized varieties; otherwise, opt for the full-sized ones. Grow vegetables with a large amount of nutritional value and calories such as sweet potatoes and leeks. Avoid hybrids and choose open-pollinated versions of all your vegetable seeds. This will allow you to save your seeds for the next year's planting. Pick early and late-season crops to take advantage of the entire length of your growing season.
Use French intensive or square-foot gardening methods to get the greatest yield from the soil. Plant each seed so the adult plant's leaves will barely touch its neighbors with no space in between. You can find this distance by looking on the seed package. The planting instructions should tell you to plant something like every 4 inches in 2-foot rows. This tells you that the plants can grow every 4 inches. Plant them with this spacing in every direction in blocks, rather than rows. Leave the smallest space possible between blocks, just enough to walk through to tend the vegetables.
Grow vining plants on stakes, fences or tomato cages to free up soil underneath. Plant pole beans at the base of corn stalks. Support heavier crops like melons and gourds with fabric slings so they can still grow vertically.
Install a soaker hose system to concentrate water at the base of the plants rather than watering the entire garden. Allow one section of the garden to soak for a few minutes, then move the hose to cover another section. Continue this until the entire garden has been thoroughly watered.
Pull up dead and dying plants in the fall and replant the soil with cool-season crops such as cabbages, carrots, broccoli and onions. Quicker crops such as radish and lettuce do well in the fall, as well, as long as the worst heat of summer has passed.
Things You Will Need
• Shovel
• Compost bin
• Wheelbarrow or tarp
• Seeds
• Tomato cages and stakes
• Fabric slings
• Soaker hose
About the Author
Victoria Bailey
Photo Credits
• Jeff Randall/Lifesize/Getty Images
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English Revolution and Seven Year Global War (1754-63)
The English Revolution
There were struggles for democracy against the rule of Absolute Monarchy in England. The English Civil War (1642-51) was fought between the Parliamentarians and the pro-Monarchy Royalists. The Parliamentarians were against the absolute rule of King Charles I who believed in the Divine Right of the King to rule. They opposed the levy of tax by the King without the consent of Parliament. The result was:
• Execution of the King.
• End to monopoly of Church of England (which was pro Catholics) over Christian worship in England.
• Establishment of the principle that the King cannot rule without the consent of Parliament.
Glorious Revolution of 1688
Glorious Revolution of 1688 in England legally established the supremacy of Parliament. It was during this revolution that the Parliament, for the first time, appointed the King. The King was removed and his son-in-law, the William of Orange from Holland was made King. Thus, from a limited constitutional monarchy established by the English Civil War (1642–1651), England transitioned to a Democracy with supremacy of Parliament.
Seven Year Global War (1754-63)
The Seven Year Global War was fought from 1754 to 1763, actually a period of nine years, between France and Britain. Other European powers like Spain, Prussia (Germany) & Austria also got engaged in the war. Known as the Global War since it was fought on different battlegrounds including North America, Caribbean, India, West Coast of Africa and in Europe
“The main reason behind the war was the quest for hegemony over colonies between Britain and France”
In North America, the British had 13 colonies on the Eastern coast along the Atlantic Ocean. They wanted to expand westwards for want of more raw materials and an increased export market in North America. But the west was under the domination of France. The French were anxious to hold on to Western North America to prevent British hegemony in the world political and economic affairs.
Seven Year Global War
Britain was undergoing the Industrial revolution (1750 onwards) at that time, which was making the British goods much more competitive in the world markets. Also, Britain was emerging as a dominant sea power and its maritime trade profits were soaring. Thus, France feared that a stronger Britain in North America would soon threaten the French colonies in the Caribbean.
They were right and in Caribbean the British fought against Spain and France who controlled the profiteering sugar plantations in their Caribbean colonies.
The West African Senegal had large natural resources, especially of Gum, and the French trading ports here, came under the British attack.
In 1760-61 the Battle of Wandiwash between the French and the British established the British supremacy in South India while the French were restricted to Pondicherry.
Result: Treaty of Paris of 1763
The Treaty of Paris of 1763 signed after the 7 Year War had the following clauses:
• Britain got Canada from France and Florida from Spain.
• France was allowed to retain its Caribbean sugar islands.
• Spain’s control over Cuba and Philippines was recognized.
The effect of the Seven Year War on world politics was that it reduced the domination of France, while Britain Consolidated its colonial power. Also, it laid the ground for American Revolution (1765-83) & French Revolution (1789).
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1. The above information is helpful for General Studies preparation. You can check different IAS portals for more information or if you want to start preparation for UPSC exams, enroll yourself at the best IAS Coaching Academy and know how to prepare for such examinations.
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Browse themes
About publications
Information for G01785
PLA Notes CD-ROM 1988-2001 25 Numeracy in REFLECT
Journal article
Document begins: PLA Notes CD-ROM 19882001 25 Numeracy in REFLECT Nicola Foroni and Kate Newman Introduction through the formal system. They have been taught that there is only one right way, and only one right answer, in mathematics. Thus, it is necessary to go back to some basic `There does not exist a single illiterate adult who has not acquired some mathematical questions, including: why teach numeracy? knowledge and/or a mental logic that they Can numeracy work contribute to, and be can apply' interwoven with, the empowerment process? Luis Orrellana, El Salvador What particular approaches to numeracy can be integrated with the REFLECT process? `Though people can live without being able to read and write, the ability to operate Why numeracy? mathematically is an essential element of everyday life' Teresa Casteneda, Peru There are many reasons for strengthening the role of numeracy within literacy programmes and, specifically, within REFLECT Despite the above statements, mathematics is programmes. These reasons will vary from often given second place in literacy context to context, but the sorts of arguments programmes. Even in progressive literacy that have been used by REFLECT programmes, numeracy is often an appendage, practitioners in different contexts include: addressed using more ...
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"language_score": 0.88112872838974,
"url": "https://pubs.iied.org/G01785/"
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Cooling of electric machines
Why is an effective cooling important?
The thermal behavior of an electric machine is an aspect often neglected in its design process. The machine is designed only using an electro-magnetic point of view. The design of the cooling system is often the last step and must adapt to all the electro-magnetic constraints.
Temperature levels have a direct impact on the lifespan of a machine insulation system. Each machine has an insulation class for its windings corresponding to an operating temperature. The lifespan of a machine is 20,000 hours at its operating temperature. A basic model to predict the lifespan of a machine is to divide it by 2 for each 10°C above the operating temperature [1]. If the temperature of the machine is under its operating temperature, the lifespan is multiplied by 2 for each 10°C difference.
Temperature has also a direct impact on the electric performances of the machine: as an example it increases the winding resistances, and changes the remanent flux density of permanent magnets. Several studies [2][3][4] show how the electromagnetic performances decrease when the internal temperature rises. When the temperature increases from 25°C to 100°C the efficiency decreases of 1% up to 5%. These changes can be considerable considering the complete lifetime of a machine (e.g. wind turbine generator annual energy production). A better cooling of a machine gives more durability and more efficiency. Investing in the cooling system optimization at the design stage of the machine can give significant long-term cost savings.
What are the critical parts of the machines?
Magnets. The temperature of the magnets must be under a certain threshold. Over this threshold, magnets lose their magnetic properties which are critical for the electric performances.
Windings. The temperature of the windings is also very important for a machine. Due to the generation of Joule losses, it is often the highest temperature. The critical temperature for a winding depends on the material used for its insulation.
Bearings. Bearings are the location of mechanical losses which can be very important in case of high rotational speed. High temperature in bearings will reduce the durability of the machine.
What are the different cooling architectures?
Passive/Active cooling. Two options exist for the cooling. The first option is passive: no external source of power is needed. Different mechanisms can be used for passive cooling: the rotation of the rotor induces air movements, the natural convection around the exterior of the machine, fins to increase the exchange surface, etc. In case of active cooling, the flow in the machine is induced by an external source, a fan for example.
Open/closed machines. In an open machine, the air is directly taken from the ambience, circulates inside the machine, and is rejected in the environment. In a closed machine, air circulates in a closed circuit and must be cooled by a heat exchanger. The two configurations have pros and cons. An open circuit is more compact and need less ventilation power. A closed circuit will be more independent from the external conditions. On the contrary, the open circuit will be more affected by outside elements (humidity, dusts, etc.). The closed circuit will need more space and more power due to the heat exchanger.
What are the best strategies for optimization?
To have a good strategy for optimization, it is important to have a clear vision of the objectives and the constraints of the problem. A good cooling system is not necessarily a system with the lowest temperature levels. Those systems would generally have high energetic cost: the ventilation power needed would be very high. As a result, an optimization of a cooling system is often a multi-objective problem with two goals: increases the heat dissipation and decreases the ventilation power (also known as hydraulic/aeraulic power). Some objectives can also be translated in terms of constraints. For example, instead of trying to reduce the temperature of magnets, a constraint on their temperature can be used.
[1] O. Barré and B. Napame, “The Insulation for Machines Having a High Lifespan Expectancy, Design, Tests and Acceptance Criteria Issues,” Machines, vol. 5, no. 1, p. 7, Feb. 2017.
[2] Aimeng Wang, Heming Li, and Cheng-Tsung Liu, “On the Material and Temperature Impacts of Interior Permanent Magnet Machine for Electric Vehicle Applications,” IEEE Trans. Magn., vol. 44, no. 11, pp. 4329–4332, Nov. 2008.
[3] T. Sebastian, “Temperature effects on torque production and efficiency of PM motors using NdFeB magnets,” in Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting, 1993, vol. 1, pp. 78–83.
[4] M. Beniakar, T. D. Kefalas, and A. G. Kladas, “Investigation of the Impact of the Operational Temperature on the Performance of a Surface Permanent Magnet Motor,” Mater. Sci. Forum, vol. 670, pp. 259–264, Dec. 2010.
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"url": "https://eomys.com/articles/article/refroidissement-des-machines-electriques?lang=en"
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“Dr. Seuss is the king and genius of phonemic awareness.”
What is Phonemic Awareness?
Phonemic awareness is:
The ability to hear the individual parts of words, separate the parts, put them back together and then change them to make new words
It is a strong indicator of reading success (once you add print, it become phonics),Usually developed naturally through reading rhyming books, singing songs, and chanting nursery rhymes.It is usually secure by the end of first grade.
A student with developed phonemic awareness can:
Enjoy language and play with its sounds
Understand that what we speak can be divided into
individual words-concept of word
Break words into syllables (parts/chunks)
Provide rhyming words, find the words that rhyme
Segment words into their individual phonemes (sounds) cat
becomes /c/ /a/ /t/
Blend individual phonemes (sounds) into words: /d/ /o/ /g/
becomes dog
Identify the beginning, middle and ending sounds in words
Match words with the same beginning sound
Change beginning or ending sounds orally to make new word.
Phonemic awareness has nothing to do with intelligence, but children without it will have a difficult if not impossible time learning the sound-spelling correspondences (phonics).
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"url": "https://papahere.wordpress.com/dr-seuss/phonemic-awareness/?shared=email&msg=fail"
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Watch CBSN Live
Scientists: We've Cracked Wheat's Genetic Code
British scientists have decoded the genetic sequence of wheat - one of the world's oldest and most important crops - a development they hope could help breed better strains of the global food staple.
Wheat is grown across more of the world's farmland than any other cereal, and researchers said Friday they're posting its genetic code on the Internet in the hope that farmers can use it as a tool to improve their harvests. The discovery could also prove handy to genetic engineers.
University of Liverpool scientist Neil Hall said that the code would serve as "the reference - the starting point that new technology and new science can be built upon."
He said that, for example, the information could help farmers better identify genetic variations responsible for disease resistance, drought tolerance and yield. Although the genetic sequence being published Friday remains a rough draft, and additional strains of wheat need to be analyzed for the work to be truly useful, Hall predicted it wouldn't take long for his work to make an impact in the field.
"Hopefully the benefit of this work will come through in the next five years," he said.
Among the potential benefits of tougher strains of wheat: Lower prices for bread and greater food security for the world's poor.
Wheat is a relative latecomer to the world of DNA mapping. This year marks the 10th anniversary of the date the human genome was laid bare. Other crops have had their genetic codes unscrambled within the past few years - rice in 2005, corn in 2009, and soybeans earlier this year.
The reason for the delay in analyzing wheat's genetic code, Hall said, was that the code is so massive - far larger than corn or rice and five times the length of the one carried by humans. One reason for the size is that strains such as the Chinese spring wheat analyzed by Hall's team carry six copies of the same gene (most creatures carry two.) Another is that wheat has a tangled ancestry, tracing its descent from three different species of wild grass.
But sequencing techniques have improved dramatically over the past decade, and scientists were able to draw up their draft of the code in about a year.
Although the code may yet see use by genetic engineers hoping to craft pesticide-resistant strains of wheat, Hall was at pains to stress the conventional applications of his work. Until now, breeders seeking to combine the best traits of two strains of wheat would cross pollinate the pair, grow the hybrid crop and hope for the best.
Once they know which genetic markers to look for, Hall said, new forms of wheat could be rolled out far faster.
The cracking of wheat's code comes at a time when prices have shot up in the wake of crop failures in Russia, highlighting how the vagaries of world food production can hit import-dependent countries such as Egypt.
Concerns over climate change, water shortages and population growth have loomed in the background for years. New risks include a destructive mutant form of stem rust. The reddish, wind-borne fungus - known to scientists as Ug99 - has devastated wheat crops in places such as Kenya, where up to 80 percent of the wheat in afflicted farmers' fields have been ruined.
Alexander Evans, an expert in resource scarcity issues at New York University, welcomed the announcement as something that would be "really helpful in helping farmers producing food that will meet those challenges."
But, as one British paper hailed the announcement as the most significant breakthrough in wheat farming for 10,000 years, Evans warned against putting too much faith in genetics, saying that reforming the politics and economics of food distribution was easily as important.
"We have to be very careful about saying that science will feed the world," he said.
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Television Newscasts
This Television Newscasts lesson plan also includes:
When we watch news broadcasts on television, we receive a much more visual perspective than when we read the newspaper. How do sets, clothing, and music contribute to our understanding of the story? Compare American and Canadian news broadcasts by looking at the specific elements and asking the questions listed. As an extension activity, learners can produce their own school newscast. Get your class involved and thinking critically about the world around them!
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Resource Details
11th - 12th
English Language Arts
6 more...
Resource Type
Lesson Plans
3 days
Instructional Strategies
Collaborative Learning
2 more...
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Introduction to Camera Shutters
As you’ve previously learned, the primary role of the shutter is to control the length of time that light is permitted to pass through the lens to the image sensor. Beyond that, the shutter controls a critical aesthetic element, the perception of movement in photography.
Shutter Priority auto-exposure mode, Bulb, and Time
Shutter Priority mode is an automatic exposure mode in which the photographer selects the desired shutter speed, and the camera attempts to achieve optimal exposure by varying the aperture. Shutter Priority mode is commonly indicated as S or Tv (for time value) on most cameras’ mode dials. Shutter Priority mode is different from other automatic exposure modes because it allows photographers to control the perception of motion, either by freezing movement, showing movement, or minimizing camera shake.
Your camera may offer two additional shutter-specific functions known as Bulb and Time. Pressing the shutter button in Bulb mode (often labelled B) will activate the shutter and keep it open for as long as the button remains pressed. Releasing the button will terminate the exposure. Pressing the shutter button once in Time mode (often labelled T) will open the shutter, and pressing it again will close the shutter. Both Bulb and Time modes are intended for long exposures. They are often used with wired or wireless remote shutter releases to avoid vibrations induced by touching the camera during exposure.
Focal plane shutters
As the name suggests, the focal plane shutter is positioned just in front of the plane of the image sensor. In modern cameras, focal plane shutters consist of two separate metal “curtains” (better described as overlapping blades) that travel vertically during exposure. When primed for exposure, the top (“second”) curtain is in a retracted position above the frame, and the bottom (“first”) curtain is fully extended upward, blocking light from the image sensor. Upon full depression of the shutter button, the image sensor activates, and the first curtain retracts down to uncover it; after a precise interval, the second curtain extends down to terminate the exposure, and the image sensor deactivates.
The process is slightly different in mirrorless cameras because their electronic viewfinders and displays receive a real-time video feed from the image sensor in place of a DSLR’s optical viewfinder. When taking a picture, the camera momentarily closes, or “primes,” the shutter before engaging as per the description above.
In both styles of cameras, the shutter curtains accelerate to a constant velocity regardless of the shutter speed. At slower shutter speeds, the first curtain retracts to uncover the image sensor fully, and after a precise interval, the second curtain closes. Beyond a certain threshold, faster shutter speeds are achieved by timing the second curtain to start closing before the first curtain has fully uncovered the image sensor. The horizontal slit formed between the two curtains exposes the image sensor as it travels across its surface. Increasing the shutter speed narrows the slit by reducing the interval between the first curtain starting to open and the second curtain starting to close. On modern cameras, the precise engagement and fast movement of the shutter curtains can form very narrow slits that achieve exposures of 1/8000 seconds.
There are three main disadvantages to focal plane shutters. First, they typically have a hard limit for flash synchronization. The fastest shutter speed at which an image sensor is completely uncovered is known as its X-sync or flash synchronization speed. The fastest available X-sync speed on modern cameras is typically 1/250 second. Using a flash at faster shutter speeds results in uneven illumination of the image sensor as it’s being exposed by a travelling slit. Cameras with physical shutter speed dials often mark the X-sync speed with an “X.”
Secondly, focal plane shutters suffer from a phenomenon known as shutter shock, which are the minute high-frequency vibrations created by the shutter curtains as they accelerate into motion and decelerate to a stop. In DSLRs, the effect is exaggerated by the mirror’s slap, which is the vibrations induced by the speedy raising and lowering of the mirror that gives SLRs their distinct sound. While mirrorless cameras don’t experience mirror slap, they suffer from extended shutter shock. As a rule of thumb, if you can feel the vibrations through your hand, they have the potential to affect your image below a specific shutter speed.
Lastly, focal plane shutters may induce an image distortion known as a rolling shutter when photographing fast-moving subjects at shutter speeds faster than X-sync. Imagine shooting a fast-moving subject with a static camera. Exposure of the image sensor is accomplished through a narrow slit. As the narrow slit travels across the focal plane, it exposes minutely different instances of time in the subject’s progression within the frame. The resulting rolling shutter distortions vary depending on your subject’s direction of motion. When the subject’s movement within the frame is perpendicular to the shutter curtains, it may appear slanted; subjects moving in the direction of the shutter curtains will appear elongated or stretched; and, subjects moving in the opposite direction of the shutter curtains will appear foreshortened or compressed. These phenomena occur incredibly rarely in practical photography.
Leaf shutters
The leaf shutter, or central lens shutter, consists of several metal blades, or leaves, in a circular arrangement that is similar to an iris diaphragm. During exposure, the blades open and close very quickly. When opened, they retract to clear the aperture and allow proper exposure. When closed, the edges overlap to ensure that no light penetrates the assembly. In modern photography, leaf shutters are used predominantly in lenses designed for medium and large format cameras. They also appear in several fixed-lens consumer-oriented enthusiast cameras, such as the Sony DSC-RX1R II and Fujifilm X100F. There are several significant differences between leaf and focal plane shutters.
First, the leaf shutter is built directly into the lens and is located near the iris diaphragm. This adds to the mechanical complexity of a lens; lenses that feature leaf shutters are typically more expensive than similar lenses without them. Furthermore, a leaf shutter does not preclude a camera from having a focal plane shutter; a camera with a focal plane shutter can be fitted with a lens using a leaf shutter.
Two, leaf shutters fully expose the entire recording surface at all available shutter speeds. The practical benefit is that flash synchronization is available throughout the shutter speed range. Since modern medium format leaf shutters can attain exposure durations as fast as 1/2000 second, this gives them a tremendous advantage over camera systems with focal plane shutters with regards to flash photography.
One of the primary drawbacks of the leaf shutter design is that the central portion of the image sensor is exposed for longer than the edges, which causes both vignetting and distorted bokeh. The effect is hard to notice at slower shutter speeds, or when relying exclusively on flash for illumination (because the flash fires at the precise moment the shutter is fully open). It becomes increasingly prominent with faster shutter speeds and larger apertures, which aren’t recommended.
Electronic shutters
An electronic shutter is a function of an image sensor that allows it to activate and deactivate its reading of light over a set period of exposure without the aid of mechanical curtains or blades. For example, if your shutter speed is set to 1/100 second, the image sensor will read the light values striking its surface for 1/100 second. It activates upon pressing the shutter button and deactivates after the set period. Electronic shutters can attain incredibly fast exposures, with some cameras reaching speeds of 1/32,000 second! In addition, they’re totally silent, and, like leaf shutters, free from the vibrations induced by shutter shock. Unfortunately, currently available electronic shutters have several disadvantages: rolling shutter, absolutely no flash synchronization, and the potential for banding when used with high-frequency lights, such as fluorescent tubes and LEDs.
Electronic shutters exhibit a far more severe form of the rolling shutter effect than focal plane shutters. It’s a consequence of how CMOS image sensors (the most common type in use today) record picture information, and is most commonly experienced as the “Jell-O” effect in quick-panning digital videos. Unlike CCDs, CMOS image sensors cannot record the light values from every pixel on their surface simultaneous. Instead, the sensor activates a single horizontal line of pixels at a time until the entire sensor is recording light. After a precise interval equal to the set exposure duration, the image sensor follows the same sequential process to terminate exposure and record the data. This is a relatively slow process in comparison to the speed of mechanical shutters. The curtains of a focal plane shutter can travel across the span of the image sensor much faster than the sensor can cycle the exposure and capture of successive lines of pixels to completion, even though each individual line of pixels may be exposed for a shorter total duration. For this reason, digital cameras that use mechanical shutters (leaf or focal plane) will always activate the image sensor before the shutter curtains open and deactivate it after the shutter curtains have closed.
The remaining disadvantages of electronic shutters all stem from the rolling shutter effect. Most cameras disable the flash when shot with an electronic shutter because the results would be similar to using a focal plane shutter above the X-sync speed (see above). Lastly, at faster shutter speeds, electronic shutters may capture banding in the light cast by LEDs and fluorescent bulbs and tubes. Lights operate at the utility frequency of the AC current in your country. In North America, the AC frequency is 60 hz, which means that the power to the light cycles on and off sixty times per second. Unlike mid- to high-wattage tungsten bulbs, which retain enough heat through their off cycles so as not to show a noticeable light loss, LED and fluorescent lights lose and gain brightness sixty times per second. When taking a picture under such lighting conditions, the scene’s ambient light levels would fluctuate as the electronic shutter scans sequential lines of pixels. The resulting pattern, a gradual transition between light and dark across portions of the photograph lit by the light source, is known as banding.
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Storyboard Text
• Have harsh cold winters, rocky soil and lumber. Also fishing and Whaling is a popular activity.
• New England
• Mid Atlantic
• They had fertile soil and flat land. There was religious tolerance. The people there were Quakers, and they had religious freedom and diversity They were called the bread colonies because they had a lot of wheat and grains. They had market towns where they'd buy and sell things.
• $outhern
• In these plantations the farmer/owner grows cash crops (Tobacco), rice, Indigo and cotton. The south belonged to the church of England and their religion is Anglican. In the south they also had counties. There were savannahs since tbe houses were spread out.
• New England
• The church was the center of life there, and they were very strict about religion. Puritans lived there. Town meetings were established to help solve problems in the villages. If you weren't from the church of England then you'd be persecuted.
• Mid Atlantic
• They raised livestock and fished for fish
• In the south they do a lot of farming. They have big plantations owned by rich farmers. The farmers owned slaves and most made the slaves do slave labor. The climate in the south is hot and humid. The soil was also rich for farming.
• $outhern
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2_Herders2 Uzbekistan Silk Road
A herd of sheep flowing through high altitude slopes (2000m elevation, Uzbekistan).
Michael Frachetti
If the book "The Travels of Marco Polo" can be believed, the famous Italian explorer and trader journeyed from the port of Hormuz in Persia overland via the Silk Road to the summer palace of Kublai Khan — in what was then-known as Xanadu (or Shangdu) — sometime in the late 13th century. Polo carried sacred lamp oil from Jerusalem and letters from the Pope to the Great Khan and founder of the Yuan Dynasty.
That route from the Persian Gulf to Inner Mongolia was just one of many making up the ancient network of the Silk Road — or, more accurately, Silk Roads — that for centuries connected the cities of Asia and Europe. They connected China, Mongolia, Persia, India, and more, then stretched all the way across the mountains, deserts, and steppes of Central Asia to the Eastern Mediterranean, allowing for the transport of gems and spices and silks.
While the basic geography of these routes has long been studied, largely identified by historical sites along the way, the specific details about why these roads pass where they do and how the connections were formed has not been as clear.
Now, researchers think they've found a way to explain the origins and importance of the mountain routes for these roads, routes that are essential for overland journeys between Europe and Asia. They may have originally been the paths that nomadic societies traveled with their herds across the highlands, seeking out the best places to graze along the way, according to a study newly published in the journal Nature. Without those nomadic herders, it's unlikely that the paths that allowed travelers like Polo to cross Central Asia would have existed, according to this theory.
The roads that connect cities and towns in lowland regions fit models that researchers had already created. These are based on what seem to be the easiest ways to travel between cities.
But the Silk Roads that traverse highlands and rocky mountain ranges cannot be easily explained using an "ease of travel" model.
The new "nomadic herder" model helps solve the mystery.
High mountain trails (ca. 3000 m elevation) run across the highest reaches of the Tian Shan Mountains, Kazakhstan.
Michael Frachetti
"[F]or over 4,500 years herders have exploited highland pastures in the summer, when grass resources are rich, and returned in winter to lower elevations where ecological conditions are favorable during colder months," the authors write in the study.
And in fact, that long predates the major trade routes along those roads. The earliest records for "Silk Road" trade date to around 200 BC, meaning that for centuries before that, these same paths were used by groups looking for places to graze.
Finding the best path
To develop this explanation, the researchers focused on how the routes through the highlands could have been created. They used a modeling system that processes satellite imagery and is frequently used to calculate how water will flow over an area and tweaked that system so it could show how the most fertile routes through the region under study would change over time.
Throughout each year, some parts of the area would work better for grazing land. A model of one year would show the best ways to move animals across that land.
Then, the researchers ran that model 5oo times to create overall "average" routes that would be likely to represent the best way for herders to travel through the highlands. They then checked these routes with the 258 known Silk Road sites within these high altitude regions.
Here's what those changing paths look like as they create roads over time in the model:
Animated sequence of ten iterations of “flow accumulation” simulated using the Pastoralist Participation model.
M. Frachetti
A full 148 sites fell onto the paths they'd modeled. When they made the model slightly more flexible, assuming that people and animals might stray from the "most perfect" paths by about 2 kilometers, a full 192 sites, or 74.4%, matched the routes they'd calculated.
"Frachetti and colleagues' research is innovative in breaking new ground without breaking any actual ground," write archaeologists Michael Harrower and Ioana Dumitru of Johns Hopkins University in a commentary published in Nature along with the study. "The authors' analysis represents a significant advance in the study of an ancient trade network, a development achieved through the use of tools for spatial analysis that continue to transform scholars' understanding of ancient geographies."
The Silk Road caravanserai “Tashrabat”, located at 3500 m elevation (Kyrgyzstan)
Michael Frachetti
Reshaping our view of the ancient world
In a way, this is a simple model, one that leaves out the social dynamics that could have moved routes over time and explain the sites that didn't fall onto these paths — things like hostile bandits, friendly groups to visit, and valuable trading partners that would required a bit of wandering. Changes in climate and weather could also have had an effect on these routes that may not be fully incorporated into the model.
The Silk Road caravanserai “Tashrabat”, located at 3500 m elevation (Kyrgyzstan).
Michael Frachetti
Yet the simplicity of this one origin for such famed roads shows the importance of smaller routes that nomads used for centuries. After all, that would mean the routes were created for local movement long before anyone was trying to use them to trade between Venice and China.
It's possible, according to this theory, that there could not have been actual Silk Roads connected Europe to Asia without the herding routes that built established paths through the mountains. The fact that 74% of known Silk Road historical sites fall along these paths show how important they must have been — and these models may lead researchers to new and still undiscovered Silk Road sites.
This changes the vision we have of the connecting paths as most important because of how they link the major cities to one where those internal routes were perhaps just as important on their own.
"Historical accounts typically cast large Silk Road oasis cities, political capitals, or market towns as dominant nodes within trans-continental trade and economic networks across Asia," write the study authors of the view that these major cities were the driving force behind what became the Silk Road.
"Yet these sources also describe the participation of itinerant craftsmen, merchants, nomads, monks, and others whose Silk Road experiences unavoidably took them outside the orbits of these lowland oases into mountainous realms, where alternative logics of mobility and sociality had dominated for millennia." And in those highlands, it may have been herders and nomads that were the driving forces, making them just as important as their more historically recognized urban counterparts.
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Content Literacy 101
Previewing (from A Handbook of Content Literacy Strategies)
As with any preview, a textbook chapter preview is used to see what's coming next. Many students do not know how to utilize textbook features, and may skip over them in their reading. A preview can be used to raise their awareness of the sections that have been designed to help them understand the text.
Why use it?
This strategy is particularly useful for science or math textbooks, which are notoriously dense and hard for students to comprehend. By intentionally pointing out text features, teachers can help demystify textbooks, and increase students' reading confidence.
How do I use it?
The Two-Minute Preview "provides students with an overview of the selection and helps them develop a strategic plan for reading it." It procedure is as follows:
1. "The teacher provides the class with a brief outline or checklist for previewing [see example below]. The outline or checklist will vary depending upon the purpose for reading and the type of material.
2. In pairs, students are given two minutes to preview the material and jot their responses on the preview form.
3. Then the teacher leads the class in developing a strategic plan for reading the material."
Introduction: What is the author talking about? What is the focus of this material?
Headings and Subheads: What are the topics of these sections?
Graphs, Charts, Maps, and Tables: Do I understand how to interpret this information? Can I restate it in my own words?
Margin Notes: What kind of information do they provide?
Summary: Does it provide a clear overview of the chapter?
Questions: Are the questions clear?
(Procedure and example both from: A Handbook of Content Literacy Strategies)
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"url": "http://contentliteracy101.weebly.com/previewing.html"
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by Dinesh Thakur Category: Type And Variables
A variable is an object whose value may change during execution of a program. It is a memory location used to store a data value. A variable name should be carefully chosen by the programmer so that its use is reflected in a useful way in the entire program. Variable names are case sensitive. Others are constants whose values cannot be changed during the execution of the program. However, their values have to be declared. In a program a variable may be declared as below.
General syntax for declaring a variable:
type identifier;
Here type is the data type such as int, float, double, or char as listed in Table. A constant object may be declared as below.
const type identifier = value;
Data Type
An object whether a variable or a constant must have a name (or identifier) with which it is identified. It is just like that we are all identified by our respective names. The type must be written in lowercase. For example, the declarations of a few integral variables are illustrated below.
int Students;
Students = 50;
int Packages = 5;
int Age;
const int Count= 10; // Count has constant value 10.
In the above statements, int is the type of all of these variables, that is, their values can only be in whole numbers. Students, Packages, and Age are the names of the three variables, and Count is the name of a constant object with value 10. Count and Packages are initialized with the declaration, whereas in case of Students, it is first declared and then a value 50 is assigned to it. The third variable is not initialized, a value may be assigned later in a program. Similarly, the variable having values in floating decimal point may be declared and initialized as below.
floatWeight= 51.5;
double PI = 3.14159;
In C language, the characters such as 'A', 'B', and 'C' are integer constants as per ASCII code. ASCII (pronounced as 'as-key') stands for American Standard Code for Information
Interchange. This code is now followed universally. In this code, every letter or symbol has an integral value. For example, the character 'A' is equivalent to number 65 and in computer it is stored in binary as 1000001. Similarly, 'B' is equivalent to 66 and is stored in binary number system as 1000010. The type of variables whose values are in single character or string of characters is char. Examples of char variables are given below.
char ch = 'B';
char Name [10];
Name= "Mona Lisa";
In the first line above, ch is the name of a variable, which is of type char, and it is initialized to value 'B'. In the second line, Name is the name (identifier) of an array of characters. Name is first declared and then a value "MonaLisa" is assigned to it. Remember, whenever a value is assigned in terms of a character, it has to be enclosed between single quotes ( ' ' ), as illustrated in the preceding example ( 'B' ), and when a value is in terms of a string of characters, it has to be enclosed between double quotes (" " ) . The number 10 in square bracket in the above declaration represents the number of characters in the string or elements of an array. In the above case, the number of characters in the name Mona Lisa including one space is 9. In case of strings of characters when value is declared in double quotes(" "),the system appends a null character ( ' \ 0 ' ) at the end of the string to mark its end. Therefore, the total number of characters becomes 10. However, the characters need not be exactly equal to the number in square bracket; it could be less as well but not more than what is declared. Note all the statements given above end with a semicolon (;).
Any variable declared in a program should confirm to the following
1. They must always begin with a letter, although some systems permit underscore as the first character.
2. The length of a variable must not be more than 8 characters.
3. White space is not allowed and
4. A variable should not be a Keyword
5. It should not contain any special characters.
Examples of Invalid Variable names are
Declaration of Variables
Every variable used in the program should be declared to the compiler. The declaration does two things.
• Tells the compiler the variables name.
• Specifies what type of data the variable will hold.
The general format of any declaration
datatype v1, v2, v3,.... vn;
Where v1, v2, v3 are variable names. Variables are separated by commas. A declaration statement must end with a semicolon.
About Dinesh Thakur
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"url": "http://ecomputernotes.com/what-is-c/types-and-variables/what-is-a-variables-declaration-of-variables"
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What is Considered a Normal Blood Pressure Reading?
Blood pressure is an important measure of your overall health. According to the Centers for Disease Control and Prevention, around 75 million–or roughly one in every three–American adults have high blood pressure.
High blood pressure is a very common health issue and should not be underestimated. Fortunately, there are many ways to assist in controlling the condition. The very first thing you need to do is understand how your habits affect your blood pressure numbers and the significance of those numbers.
Blood pressure is a measure of the force of blood against the artery walls as it circulates through the body. It can rise and fall throughout the day, but prolonged periods of high blood pressure can lead to health problems. There are two numbers in your blood pressure reading, and they are broken down as follows:
• Systolic blood pressure. This is the first number in the reading. It indicates how much pressure the blood is exerting against the artery walls when the heart beats.
• Diastolic blood pressure. This is the second number in the reading. It indicates how much pressure the blood is exerting against the artery walls when the heart is resting between beats.
What do the blood pressure numbers mean?
According to the American Heart Association, the blood pressure reading categories are as follows:
• Normal. Blood pressure numbers that are less than 120/80 mm Hg are considered to be within the normal range.
• Elevated. Blood pressure numbers that consistently fall between 120 and 129 systolic and less than 80 mm Hg diastolic are considered elevated.
• Hypertension Stage 1. Blood pressure numbers that consistently range from 130 to 139 systolic and 80 to 89 mm Hg diastolic are indicative of hypertension stage 1.
• Hypertension Stage 2. Blood pressure numbers that consistently range from 140/90 mm Hg or higher are indicative of hypertension stage 2.
• Hypertensive Crisis. Blood pressure readings that exceed 180/120 mm Hg constitutes a medical emergency and requires immediate medical attention.
What is hypertension?
Hypertension is the formal medical name for high blood pressure. Early stages of hypertension does not come with noticeable symptoms, so people can have hypertension for years without experiencing any symptoms. Having untreated hypertension for prolonged periods of time can increase the risk for serious health issues down the road.
How can blood pressure numbers be controlled?
People with elevated blood pressure levels are at risk for developing hypertension if steps are not taken to control the condition. If you are asking yourself how to be healthy, you should know there are certain lifestyle habits you can adopt to help keep your blood pressure in check or to lower it if it is high. These habits include:
• Get your blood pressure checked regularly. Blood pressure checks are convenient. You don’t even have to make a doctor’s appointment. Most local pharmacies will perform the test without an appointment.
• Stick to a healthy diet. Eating plenty of fruits and vegetables, while avoiding sodium, can help you reach and maintain good blood pressure numbers.
• Stay hydrated. Making certain that you drink enough water throughout the day helps to ensure all of your bodily functions are operating in an optimal fashion. If you begin an exercise regimen to help control your blood pressure, you should definitely make an effort to stay hydrated.
• Maintain a healthy weight. Being overweight or obese makes it harder for the heart to pump blood effectively throughout the body. Losing weight can help relieve that strain and lower your blood pressure.
• Exercise regularly. Staying physically active strengthens the heart, which helps it to pump blood effectively and decreases the pressure on the arteries.
• Don’t smoke and limit alcohol intake. Smoking is linked to higher risks for nearly every type of cardiovascular disease, while drinking alcohol in excess has been linked to increased fatty plaques in the arteries, which inhibits effective blood flow.
• If you have diabetes, manage the condition properly. About one-fourth of people with diabetes also have high blood pressure. Managing diabetes, including eating a nutritionally-balanced diet and exercising, can help alleviate blood pressure issues.
What are the treatment options for high blood pressure?
Besides lifestyle modifications, medications can help to bring blood pressure back to normal levels. There are several classes of medications you should speak with your doctor about if you feel your blood pressure is an issue. These classes of medication include:
• Angiotensin-converting enzyme (ACE) inhibitors
• Angiotensin II receptor blockers (ARBs)
• Diuretics
• Beta-blockers
• Calcium channel blockers
• Alpha-blockers
• Alpha-agonists
• Renin inhibitors
• Combination medications
Reader Interactions
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Nature and Definitions of Motivation
Man is an active creature by his nature. He is always engaged in some work, and continues to do some kind of behavior. He does not do any work or behavior without any purpose. And the purpose of his work is to make the fulfillment of some especial goal. For example a student studies with a great zeal and intensity while other is detached from the study. What is the cause of it? This type of question arises— Why do we take food? Why do we earn money? Why do we take education? It can be found in the answer of these questions that there are some motives for the action and behavior of any person, which motivates him, for doing action and behavior in different situations.
Krech and Krachfi eld has said clearly—The question of motivation is the question of why. In fact Needs, Driver, Incentive, Motive are the main sources of motivation. Hilguard has written—“the need gives birth to driver, the driver is the condition of developed intensity, which progresses toward the action and starting behavior. Stimulus is some thing related to external environment, which satisfies the needs and in this way diminish the driver by action.’’ The motivator can be understood in the same words of needs, desires, intensity, natural situation, decisive qualities, habits, interests, stable incentive. In short motivation is the creation of above four facts: need, driver, stimulus and complex organization.
Nature and Definitions of Motivation
The English word Motivation is originated from the Motum word of Latin language. According to the general and verbal meaning of motivation, move, motor and motion we can call any stimulus a motivation, which helps a person for reacting and behavior. This type of stimulus can be both internal and external. But from the scientific point of view, motivation is an internal power, which internally motivates a person for doing any action. This type of motivation can be called the driving power of physical instrument. The following definitions have been presented for explaining the psychological meaning of the word motivation:
1. Wood worth—Achievement = Ability + Motivation. Means Achievement is obtained by ability + motivation. The ability of a person is developed by getting motivation. This type of ability is possible by the achievement of motivation.
2. According to Lowell—“motivation may be defined more formally as a psychological or internal process, initiated by some need, which leads to an activity which will satisfy that need.’’
3. According to Good—“Motivation is the process of arousing sustaining and regulation activities.’’
4. According to Blare, Johns and Simpson—“Motivation is a process, in which a learner’s internal energies or needs are directed towards various goals and objects in his environment.’’
5. According to P.T Young—“Motivation is the process of arousing action, sustaining the activities in the progress and regulating the pattern of activity.’’
After analyzing the above definitions, related to motivation the following things are clarified:
1. Motivation is psychophysical or internal process or stage.
2. Motivated process is originated due to any need.
3. Motivated process leads towards the direction of doing any important activity.
4. This process goes on till the attainment of any purpose.
In the psychological context, the meaning of motivation is by the internal stimulus, as a consequence of which we do any action and behavior. Psychologists have not concluded external stimulus under motivation. For example hunger is such an internal stimulus, according to which we can be inspired for having the food, so hunger can be called motivation. A person can be inspired for having the food after seeing the plate of food. Here the plate is an external stimulus, but eating process did not get inspired. A man will not take the food, until he gets internal motivation, so we can say internal stimulus, which motivates a man for doing any activity, is called motivation. Motivator is more important in the motivation. So it is essential to throw light on the meaning and definition of motivator.
Motivator- Meaning and Definition
The meaning of motivator—In the action and behavior of a human being, inborn, natural and acquired instincts are hidden. These instincts inspire for behavior, so psychologists have called it motive. So we can say that the motivation instinct lies in the root of human behavior, which inspire a man for doing some activities.
The word motive should be understood by the definition given by the psychologists. Motivation is a mental set and motivator is a factor which motivates a man for doing some especial action. So we can say that motivation tells about the situation and motivators are due to its reason.
The definitions of motivator- For explaining the concept of motivator, the psychologists have given many definitions of motivator:
(1) Shaffer and others—“A motive may now be defined as a tendency to activity initiated by a drive and concluded by an adjustment.’’ This definition is evident by an example- In the state of hunger there is a contraction in the layers of stomach, and a man feels intensity on his internal side. And getting ride of this confusing stage he searches for eating material. His searching goes on until after getting the food he quenches his hunger. In this example the state of hunger is motivation. And the cause of state of hunger is called hunger motive. From this point of view the function of motivator tendency are:
• Arousing the activity,
• And continue it,
• And continue to lead it towards the definite dimension until he gets the goal.
According to the above definition hunger drives and inspires for having the food. And hunger drive comes to an end after having the food. And there is difference between the motivator tendency and motivation of food. Motivator is an extended word under which need, motive, driver and incentive all come.
(2) Gates and others—“Motives take a variety of forms and are designated by many different terms, such needs, desires, tensions, sets determining tendencies, attitudes, interests, persisting stimuli and soon.’’
(3) Wood worth—“A motive is a state or set of the individual which disposes him for certain behavior and seeking certain goals.’’
(4) MacDougal—“Motives are conditions physiological and psychological within the organism that dispose it to an act in certain ways.’’
(5) Gilford—‘’A motive is any particular internal factor or condition that tends to initiate and to sustain activity.’’
(6) J. Drever—"Motive is an effective - conative factor which operates in determining the direction of an individual’s behavior towards an end or goal, consciously apprehended or unconscious.’’
(7) Thomson—"Motive is an effective and conative factor which operates in determining the direction of an individual’s behavior towards an end or goal, consciously apprehended or unconscious.’’
The sides of Motivation
We can say on the basis of above definitions that the initiation of motivation is by some need and end after the attainment of any goal. Motivation is an extended word. There are the three sides of motivation, which are following:
1. Need
2. Drive
3. Incentive
1. Need—There are some fundamental needs for sustaining the life of every creature, And it is necessary to fulfill them. As it is necessary to fulfill the needs of water, air, food, sleeping. If these physical needs are not met, tension and imbalance arouse in the body, as a consequence of which he becomes activated. For example being hungry, activeness is sustained in a man until he gets his food. After getting the food his need is completed. And his tension and his activeness come to an end. Giving the definition of need Boring and Langefield have said-“A need is tension within an organism which tends to organize the field or organism with respect to certain incentives of goals and incite activity directed toward their attainment.’’
Therefore, the psychologists have also said need, such as a condition, which is felt in the reduction and absence of any thing. Man is always active to complete this reduction. As for the fulfillment of consumption of eating material he tries to get the food, he searches for water for the fulfillment of water; here the reduction of water and eating material is the needs of water and food.
2. Drive—The stage of tension that arises due to the needs of creature is called drive. Thus need is
generated by the drive—As-thirst-drive, by the need of water and hunger-drive originated, by the need of food. The feeling of hunger and thirst is an internal stimulus. This generates tension in the man. A man does action for having food and quenching the thirst. Thus to inspire for doing action is the chief characteristics of drive. Psychologists have given the definitions of drive in this way:
• Deshiyal—“Drive is original source of energy that activates the human organism.’’
• Sheffar and others—“A drive is a strong, persistent, stimulus that demands an adjusting response.’’
3. Incentive—Incentive is a thing of external environment, which satisfies the drives after fulfilling the need. For example—hunger is a drive, which is satisfied by the food. Therefore food is an incentive for ‘hunger- drive’. According to Hillgard-“In general, an appropriate incentive is one that can reduce the intensity of a drive.’’The internal stage of a man is indicated by the need and drive, while incentive is presented in the external environment. In the words of Boring and Lang field, “an incentive may be defined as an object, a situation or an activity which excites, maintains and directs behavior.’’
Relation among Need, Drive and Incentive
There is a close relationship in these parts of motivation. Hillgard has cleared the need drive incentive formula. How does this formula work, has been clarified very well after the understanding of the meaning of these thrice. Hillgard has written about the close relationship of these three. “Need gives rise to drive state which is a drive of heightened tension leading to activity and preparatory behavior and the incentive in the external environment that satisfies the need and thus reduce the drive through consummators activity.’’
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"url": "https://www.educationaltheory.info/2018/05/nature-and-definitions-of-motivation.html"
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Shapes Splat
In this learning game, students identify shapes by shooting the shape that matches the given word. There are four games that students can practice. Students can identify basic shapes, shapes with rotation, more shapes, or three dimensional shapes. After selecting the category to be played, students can choose to play at their own pace or against the clock. As you match the correct word with the correct shape, watch the points soar.
Courtesy of Knovation
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"edu_score": 3.921875,
"fasttext_score": 0.860400378704071,
"language": "en",
"language_score": 0.9424111843109131,
"url": "https://www.techlearning.com/resources/shapes-splat"
}
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Brain behaviour - Mozart on the mind
Just listening to classical tracks may not raise children's IQ, but learning music improves their memory and ability to learn other things. Nigel Hawkes looks at the evidence
The function of music has long puzzled scientists, especially those interested in human evolution. It appears to be ancient, and universal: archaeologists have unearthed bone flutes dating to at least 30,000 years ago, though nobody has the least idea what tunes they played, and music is enjoyed in every culture.
Some scientists believe that an appreciation of music is imprinted into the brain, rather like the ability to master language. Yet music, unlike speech, sex or food, seems to offer no survival advantage. So why is it so powerful and so ubiquitous?
There is no final answer, but many other mysteries of musical perception are beginning to yield to the power of modern brain scans.
These have confirmed that, while music occupies areas of the brain that overlap those of speech, they are not identical; and they have shown that there is no single area of the brain labelled music. Rather, musical appreciation calls upon diverse areas of the brain, such as the auditory cortex for tones and limbic system for emotion.
All this becomes plainer when the brains of musicians are examined. Like the muscles of an athlete, specific brain regions are larger or better developed in people who have spent years in music training.
The auditory cortex is 130 per cent larger in musicians, for example, demonstrating that learning music increases the number of brain cells used to process it. In violinists, the brain regions that receive inputs from the fingers of the left hand are significantly larger, because those fingers determine the sound the instrument makes. There is no corresponding increase in the areas devoted to the right hand, which merely holds the bow.
Keyboard players, who need to learn perfect co-ordination of the hands, show exaggerated growth in the anterior corpus callosum, the band of fibres that connect the motor areas responsible for each hand. The earlier children start to learn music, the more pronounced the changes.
There have been plenty of claims of music's ability to improve the human brain. However, the evidence is equivocal, and something almost everybody believes to be true - that listening to Mozart can raise the IQ of infants - almost certainly is not.
But there is persuasive evidence that learning music improves memory and the ability to learn other things. For instance, Canadian scientists compared a group of children aged between four and six who attended a Suzuki music school with a similar group who had no music lessons outside school. They found that the children who learnt music showed changes in brain responses and performed better in memory tests than the others.
Laurel Trainor, who led the research, said: "It suggests that musical training has an effect on how the brain gets wired for general cognitive functioning related to memory and attention."
People respond to music in a peculiar way that illustrates how it makes use of many different areas of the brain. For those affected by synaesthesia (where we experience senses simultaneously that we'd normally experience separately), musical keys trigger the sensation of particular colours. And it seems to work like a drug: among the young, the iPod generation carries its opiate of choice wherever it goes, blocking out the world while sucking in a mind-altering stream of song. There is also a whole branch of medicine called music therapy and a few studies have shown some benefit of it on depression.
But by far the most celebrated scientific study is one that gave rise to the so-called Mozart effect. Published in 1993 by Francine Rauscher and colleagues, it showed that college students who spent 10 minutes listening to Mozart's Sonata in D major for Two Pianos performed significantly better in an IQ test than those who hadn't.
Although the original experiments were done on college students, the message was quickly and inaccurately subverted to apply to infants. In 1998, the State of Georgia even passed a bill to distribute free classical CDs to new mothers. A review of 16 studies that attempted to reproduce the original experiments failed to show any significant change in IQ. Any changes that were detectable, said Christopher Chabris of Harvard, author of the review, were attributable to changes in mood or arousal and were short-lived.
Listening to Mozart never did anybody any harm and may even have given some children a taste for classical music, but claims that it enhanced their IQ are almost certainly misplaced.
So why does music play such a big part in human affairs? Biologists and psychologists have suggested, variously, that music enhances human survival by aiding courtship; promotes social cohesion in groups; and is a form of play.
But for Stephen Pinker of Harvard, an evolutionary psychologist, music is "auditory cheesecake" - a lucky by-product of human history that keeps us amused but has no evolutionary significance. He believes it is simply a side-effect of the evolution of language.
Whatever the explanation, science has made plain what music lovers have always known. It is an activity that can dominate and shape the mind, enrich the spirit, raise morale and give huge and continuing pleasure.
Nigel Hawkes is the former health editor of The Times. This is an edited version of an article that appeared in the December issue of Gramophone magazine
Trainor, L., et al (2006) One Year of Musical Training affects Development of Auditory Cortical-evoked Fields in Young Children, published online in Brain, 129:10, 2593-2608.
Rauscher, F.H., et al (1993), Music and spatial task performance, Nature, 365, 611.
Chabris, C.F. (1999) Prelude or requiem for the `Mozart effect'?, Nature, 400, 6747, 826-7.
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A field-programmable gate array (FPGA) is a type of microchip that can reconfigure itself after it has been manufactured, hence "field-programmable". The technology has found use in emulation as it can reimplement the hardware without having to resort to any kind of binary translation to a computer platform's native code. Instead of adhering to an instruction set or a programming language, FPGA chips are instead programmed using a hardware descriptor language (HDL) that describes the components and logic needed to run the software. This programming isn't permanent; corrections and other changes can be made afterwards so that it isn't limited to one application like an ASIC.
Despite what one may think, FPGAs are not a new technology; they've been around for as long as Macintoshes have been, with manufacturer Altera being the first to introduce an FPGA to the market in 1984. While they already had use in aftermarket cartridges (like setting up mappers for ROMs like the SD2SNES does), using them in place of entire consoles was considered esoteric until commercial devices using FPGAs were released in the mid to late 2010s.
List of aftermarket reimplementations[edit]
Product Manufacturer Reimplements MSRP
Super Nt Analogue Super Nintendo Entertainment System $189
Nt Mini Analogue Nintendo Entertainment System $449/$499
MegaSG Analogue Sega Genesis $189
AVS retroUSB Nintendo Entertainment System $185
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Winter Science Activity for Kids: How to Make an Unbreakable Egg
Looking for a fun winter science activity for kids? Amaze them with this unbreakable egg! This activity is so easy to do, it only requires two supplies!
Unbreakable Egg Winter Science Activity for Kids
Have you ever broke an egg before? What happened? Chances are you had a yolk filled mess on your hands. Well what if you could make an egg unbreakable? It is easier, and more possible than you may think! If you are looking for the perfect science activity for kids, this one fits the bill. With just a few supplies you already have around your kitchen, you can in fact make a fresh egg unbreakable. Take a look below at how to enjoy this simple science activity for kids in your own house, as they will love creating an unbreakable egg!
Winter Science Activity for Kids: How to Make an Unbreakable Egg
Unbreakable Egg Winter Science Activity for Kids Supplies
Supplies needed:
• Fresh eggs
• Cling wrap
That’s it! When is the last time you were able to create a science experiment for kids using just two supplies? It does not matter what size the eggs are, nor does it matter what brand the cling wrap is. Just as long as you have eggs and cling wrap you are ready to roll.
1. Begin by talking about why eggs are so fragile. Let children feel the eggs and make guesses as to why they break so easy. Explain to them how the shells are thin and fragile, making the eggs easily breakable.
2. Talk about some ways that eggs can be protected. Could you wrap them in bubble wrap? Would tissue paper protect it? How does an egg carton protect the eggs and keep them from breaking? Talk about how eggs can be protected and give some examples.
3. Now you can complete the experiment. Wrap the cling wrap around the egg so it has several layers.
4. Instruct children to them place the egg in their palm and wrap their fingers around it as much as possible.
5. Squeeze the egg as hard as possible. You will notice that the egg does not break!
6. Now remove the cling from the egg. You can try the experiment again, however this time prepared to be messy!
So how does this work? Egg shells are very thin and fragile, but the shape of the egg itself helps protect it. When you apply pressure evenly all around the egg, it will not break. When you hold the egg in your hands and press it applying pressure to the entire egg, it is able to protect itself. When an egg is dropped and pressure is only applied to one point of the egg, it will shatter.
You can try this winter science activity for kids several times and see if you are able to break the egg using the cling wrap method suggested. Chances are as long as pressure is applied evenly, you will not be able to shatter the egg.
So there you have it! This winter science activity for kids is so simple and inexpensive and sure to teach them something new. Give it a try and see what fun it can be! Looking for more fun science activities that you can do year round? Check out how to create mystery messages with invisible ink or how to blow up balloons with gas!
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5 Responses to “Winter Science Activity for Kids: How to Make an Unbreakable Egg”
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1. Terri Grote says:
wow, had no idea this was even something you could do, I am going to share with day care and school :)
Terri Grote recently posted..Ask TerriMy Profile
2. Sarah - ITKM says:
This is an awesome activity! I homeschool so we’ll be trying this out soon = )
Sarah – ITKM recently posted..The Popcorn Factory and Cheryl’s {Valentine’s Day Gifts}My Profile
3. My oldest son has done this one multiple times. Fun!
Tiffany (NatureMom) recently posted..Co-Sleeping Safely With Your BabyMy Profile
4. Michelle says:
How cool, you learn something everyday. My 5 year old will love this.
5. Renee Smih says:
My kids will get a kick out of this little experiment. It’s very easy and will help them understand how the chicken can sit on their eggs and not break them.
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The life of bees
Bees are insects belonging to the hymenoptera order (of Greek hymen: membrane, as they have translucent and membranous wings), like wasps and ants. They live everywhere in the world, except where winter is too cold. There are many bee species (about 20.000), but the ‘honey bee’ species is called Apis mellifera (or Apis mellifica) by scientists.
A very organized social life
Just like ants, bees are social insects and cannot live alone: they need to be with a colony. A very organized colony, made of tens of thousands workers, of a few hundred drones and only one queen.
From egg to bee
According to the type of alveolus, the queen will lay a fertilized egg (future queen or worker bee) or a non-fertilized one (future drone). In any case, the egg will become a small white larva on the 4th day.
From that time on, you may determine if it is:
– A queen larva
– A worker larva
– A drone larva
— The worker bee
Also stemming from a fertilized egg, worker bees hatch in standard hexagonal wax alveoli. Fed on royal jelly for 3 days, they then eat a mixture of honey and pollen.
The cell is sealed on the 9th day. Transformations take place more slowly than in the queen, and the adult bee (or ‘imago’) tears its wax seal to join the rest of the colony on the 21st day.
Worker bees, more numerous than the other kinds (between 30.000 and 70.000 per hive) have an atrophied reproductive system. In the colony, they work continuously and are responsible for many tasks to ensure the hive runs properly. All of them deliver various tasks during their lifetime, contrary to ants (each ant accomplishes just one specific task).
The life expectancy of a worker bee depends on the season. It is about 45 days in spring and summer, about a few months for worker bees born in autumn, because they will survive all winter.
Day 1-5 CLEANER Cleans the alveoli before the queen lays a new egg and warms up the brood.
Day 4-10 NURSE May start feeding young larvae under 3 days, then royal larvae (with royal jelly) if any. Worker larvae are fed a mixture of honey and pollen after 3 days of life.
Day 8-15 ARCHITECT Builds and maintains honeycombs thanks to the wax glands on its abdomen. Is sometimes called wax bee.
Did you know?
For a colony to build 100 g of wax alveoli, it has to work for 8000 hours and consume 1 kg of honey.
Day 10-20 STOREKEEPER Stores pollen and nectar into the alveoli.
Day 15-22 AIR CONDITIONER Ventilates the hive by quickly moving its wings in order to maintain a sufficient temperature and hygrometry.
Day 20-24 SECURITY GUARD Guards the hive entrance to get rid of intruders such as wasps, butterflies and even drones from August.
Day 21 to death FORAGER Flies from flower to flower to collect nectar, pollen and propolis. In 3 weeks time, may cover 700 km to bring nature’s wonder back to the hive.
Did you know?
A forager bee flies back and forth 10 to 100 times between the hive and the flowers, depending on how far flowers are located.
— The drone (male bee)
Stemming from a non-fertilized egg, the male larva develops in a hexagonal (horizontal) alveolus, bigger than those of worker bees. Like other larvae, it is fed on royal jelly for 3 days, then on a mixture of honey and pollen that contains much more pollen than in this of workers.
This cell is sealed on the 10th day after the egg was laid. The adult drone leaves the hive on the 24th day.
Bigger, rounder and hairier than worker bees, drones have no sting.
Contrary to forager bees, they are not attached to a particular hive. When going out from April to July, drones try to fertilize a virgin queen during the nuptial flight. Then drones die. They may contribute to the pheromone and temperature balance of the hive, but this has not been determined yet.
The queen bee
Stemming from a fertilized egg, the queen bee grows in a royal (vertical) cell that is much bigger than those of worker bees.
The young queen larva is abundantly and exclusively fed royal jelly. The royal cell is sealed with wax on the 9th day. The adult queen leaves her cell after fledging, on the 16th day after the egg was laid.
As soon as she is born, the queen must kill all the larvae of the other royal cells, because there can be only one queen in the colony.
Should other queens be born at the same time, they will fight a merciless battle with their stings. Designed to sting several times, the latter is only used for this ‘royal struggle’.
The victorious queen leaves the hive a few days after hatching for a single nuptial flight (if climate conditions allow her to do so, she needs fair weather and temperature above 20°C). For the queen to be properly fertilized, she must mate with a dozen drones until her spermatheca (reservoir for spermatozoids) is full. Once fertilized, the queen goes back to the hive and will never leave it again during her 4 to 5 years of life (unless in case of swarming).
Once she is back to the hive, the queen bee starts laying eggs. She lays at will, whether male or female eggs depending if they were fertilized or not: fertilized eggs will become worker bees, non-fertilized ones will become drones. During springtime, the queen may lay more than her own weight every day, up to 2000 eggs a day (about 1 egg a minute)!
The queen also produces a number of chemical substances called pheromones that entail specific behaviors in the colony (cohesion of the bee cluster, behavior of the court…) and modify the physiology of forager bees (atrophy of their reproductive system).
Always cared for, protected and fed by worker bees, the queen lies at the heart of their attention.
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The orbital period of a satellite is the time taken to make one orbit. For the Moon the orbital period relative to the Sun is 29.53 days, but relative to the stars is only 27.26 days. That's because while the Moon goes round the Earth, the Earth also goes round the Sun, and that makes the Moon go round a full star-relative orbit, then have to go a bit further.
The Earth moves about 1 degree per day (actually 365.25/360), so in 29.53 days the Moon has to go around the 360 degrees, plus an extra 29.53*(365.25/360), making 390 degrees in total. That takes 29.53 days, so the 360 degrees must take 29.53/390*360 days, giving 27.26 (and a bit) days.
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Home About Themes Gallery Library Timeline Glossary Links Copyright
Women unite for people's power
When the National Party came into power in 1948 and introduced the policy of apartheid, discrimination and oppression against black people intensified. Women began to take up a more active political role against the government.
In the 1940s and 1950s, a number of women's organisations came into being, all of which linked up with the broader anti-apartheid struggles that were taking place.
A women's charter was adopted at the launch of the Federation of South African Women (FSAW or FEDSAW) in 1954. This charter was drawn up to unite women against political, social, legal and economic injustices Women's Charter.
FEDSAW united the ANC Women's League, the women's wing of the Coloured People's Congress of South Africa, the South African Indian Congress and the Congress of Democrats.
Dora Tamana was elected as President and Ray Simons, a trade unionist and member of the Comunist Party, was elected as the first Secretary of FEDSAW
FEDSAW supported the Bantu Education boycotts and campaigned against rent increases, housing problems and passes for women. FEDSAW was never banned, but it was hard hit by the banning of its major affiliate, the ANC Women's League on 7 April 1960.
Another significant women's organisation was founded in 1955. Black Sash was an organisation of white women who protested agaist changes in the constitution that removed the right of coloured people to vote. They later became active in providing support to people who ere arrested for violations of pass laws and to communities faced with forced removals.
Exhibitions in the classroom
Reading the Past:
SOURCE: The Women’s Charter. FEDTRAW pamphlet, date unknown.
The Women’s Charter was adopted at the launch of the Federation of South African Women in 1954. This original document outlines the aims of this charter. Read the charter and then answer the questions.
1. Draw a table with two coloumns to identify which aims of this charter is related to women’s struggles and which related to the role of women in the struggle.
2. Do you think it is important that women have their own charter separate from men? Explain your answer.
Reading the Past
SOURCE: Federation of South African Women invitation and programme, Women’s Day Commemoration, 9 to 12 August 1984
In 1983 P.W. Botha introduced a new constitution. This called for a Tricameral Parliament in which there would be three houses – one for white people, one for Indian people and one for Coloured people. Black people were excluded from any political involvement. Instead, the Koornhof Bills allowed for Black people to vote for town councillors who were meant to look after their interests. Elections for this new parliament were meant to take place in September 1984. It was in this context that the commemoration of Women’s Day took place in August 1984.
Read through this source and answer the questions.
1. What are the main issues that this invitation is calling on women to challenge?
2. How does this invitation reflect the political role that women played in the struggle?
NEXT: You strike women, you strike a rock!
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Bamako, Mali (11th Century– )
“Image Ownership: Public Domain”
Bamako, with a population of 1.8 million, is the largest city in the Republic of Mali. It serves as Mali’s seat of government and the country’s economic and cultural center. The city is located in the southwestern corner of Mali, along the banks of the Niger River. In the Bambara language Bamako means “crocodile river.” Bamako is connected to other major parts of Mali via the Niger River. Although it first came into prominence as an urban center in the Mali Empire, the precise date of its founding is unknown.
From the 11th through the 16th centuries people throughout the Mali Empire traveled to Bamako to study Islam. At one point Bamako rivaled the more famous Timbuktu as a seat of learning. Bamako diminished both in size and importance after the collapse of the Mali Empire.
Mungo Park, a Scottish explorer with the British African Association, visited Bamako in 1797 and in 1806, becoming the first European in modern times to enter the city. In 1806 Park estimated Bamako to have a population of 6,000 people, but towards the end of the century the city had become a settlement of a few hundred inhabitants.
In 1883 the French gained control of the city, which now had a population of about 1,000. They built a fort there that year and in 1908 made Bamako the capital of the French Soudan Colony. In 1923 the French completed a railroad connecting Bamako with Dakar, Senegal.
As a colonial capital, Bamako ironically emerged as a center of anti-colonial activity. With the intent of ending colonialism in Francophone Africa, in 1946 the Rassemblement Démocratique Africain (RDA) was established in Bamako. The RDA became the first French-speaking Pan-African organization in the world. By 1957, Modibo Keita, the mayor of Bamako, was named leader of the RDA.
With independence in 1960 the French Soudan renamed itself the “Republic of Mali.” Modibo Keita became the country’s first president. As people relocated to the city to escape famine and poverty in the countryside Bamako’s population increased tremendously over the next four decades.
In addition to being the political hub of Mali, Bamako is the economic and cultural center of Mali as well as its capital. Products from the countryside such as gold, rice, cotton, livestock, and kola nuts are transported to the city and packaged for international trade and domestic consumption. The city also manufactures textiles, ceramics, and pharmaceuticals for local consumption. Bamako is home to many notable institutions such as the University of Bamako, the National Museum of Mali, the Mali National Zoo, the Grand Mosque of Bamako, and the Bamako-Senou International Airport.
The buildings of Bamako have a unique architectural style. Bamako’s largest building is the BCEAO Tower, which houses the Mali branch of the Central Bank of West African States. Combining modern building techniques with local indigenous aesthetics, the tower is classified as Neo-Sudanic in design.
Bamako, like other metropolitan capitals, is challenged with issues of urban blight, massive unemployment, and underdeveloped public services. Mali’s poverty exacerbates the city’s problems.
“Bamako,” New Encyclopedia of Africa 2nd Edition, editors John Middleton and Joseph Miller (Detroit: Charles Scribner’s Sons, 2008.); Elizabeth Heath, “Bamako, Mali” Africana: The Encyclopedia of the African American Experience, 2nd Edition (New York: Oxford University Press, 2005).
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"url": "https://www.blackpast.org/global-african-history/places-global-african-history/bamako-mali-11th-century/"
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In 1859 Charles Darwin published his epoch-making ‘On the Origin of Species.’ Ideas were already abroad that life evolved, but a mechanism to allow evolution was needed. It was Darwin who
provided the mechanism with his ideas of natural selection. In its simplest form, life evolved to fit its environment. Those that did so the best thrived; those that didn’t died out. Evolution, it seemed, favoured the fittest.
Seven years later, an obscure monk called Gregor Mendel published the results of his work on the heredity principles of the pea plant. Noting that characteristics of the parent were passed on, he had, infact, discovered the science of heredity and genetics. Such a discovery was vitally important, for it not only gave a medium through which evolution could work, but it also identified a possible blueprint of life. However, Mendel’s work was to be ignored until 1900.
In 1909 the gene was coined as a term to describe inherited characteristics by Wilhelm Johannsen. We now know that genes are located on chromosomes that are found in all cells. But it took until 1953, and the work of James Watson and Francis Crick, before we understood the mechanics of deoxyribonucleic acid, or DNA. Strands of DNA exist in the gene as a double helix. Containing all the characteristics of the person or lifeform, when reproduction occurs, one strand of the double helix detaches and carries the information to the new lifeform as a genetic code.
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How to Recognize Cyberbullying
How to Recognize Cyberbullying
Monkey Business Images /
Cyberbullying is a new take on an old concept. Before getting into the cyber aspect of it, though, it’s first important to understand what the term bullying actually means.
As a teacher, I heard many students (and parents) accuse others of bullying. Sometimes, they were right. Many other times, it was students just being plain mean to each other. The term “bullying” is used so frequently today that it has lost some of its meaning.
What is bullying?
Bullying, by definition, is repeated, unwanted, aggressive behavior (both physical and verbal) that involves a real or perceived power imbalance. It is also done on purpose. Let’s break that down to better understand it. First, there must be a real or perceived power imbalance, which can be in terms of age, rank, gender, nationality, or another trait. Usually, someone vulnerable will be purposefully bullied by someone stronger or more powerful. The victim’s vulnerability can be real or just perceived as real by the bully. Bullying is also repeated and ongoing. This is where a lot of the misunderstanding takes place. If someone is rude to you once, he or she is not a bully. He or she is mean. True bullying is repeating the unwanted, aggressive actions many times, even after being asked to stop.
What is cyberbullying?
With the rise in internet usage, a new type of bully has emerged. Cyberbullying occurs when bullying takes place over digital devices, including phones, computers, and tablets. There are many avenues through which cyberbullying can take place. These include text conversations, social media sites (Facebook, Snapchat, Twitter), online forums like chat rooms, and apps where people can communicate via instant messages.
In the digital age, it has become much easier for bullies for several reasons:
• Constant contact: People have constant access to their phones and the internet, which gives them the ability to communicate 24 hours a day. This increases the likelihood that bullying can occur and makes it more difficult for a victim to escape a bully.
• Permanence: When you post something online, it’s permanent and often publicly accessible. This includes any bullying posts, which can make the effects of cyberbullying far-reaching. This can impact the victim’s reputation in a negative way, leading to judgement or further isolation from any friends or acquaintances who see the offending posts.
• Anonymous: Cyberbullies do not have to face their victims while bullying occurs, which increases the number of people who will actually bully others. Since it requires less courage, some people who would never participate in face-to-face bullying may participate in cyberbullying.
• Ignorance: Since cyberbullying happens behind a screen, the bully cannot see the immediate effect that their words or actions have on their victim. This ignorance about the true impact they have allows cyberbullying to go on for longer periods of time. Ignorance also comes from outsiders—the parents, teachers, and friends of those being bullied. It is hard for outsiders to see the cyberbullying unless they are constantly watching the victim’s online interactions, which is often not the case. This makes it harder for cyberbullies to get caught.
Who is cyberbullied?
The short answer: Anyone. Statistically speaking, however, 12-17 year old girls are more likely to report being cyberbullied than boys of the same age (37% vs. 31% respectively). Over 33% of teens reported being cyberbullied in their lifetime, and over 25% reported being cyberbullied more than once within the past month. Additionally, the more digital and social networks a student uses, the higher the chances of them being cyberbullied.
Who cyberbullies?
The short answer (again): Anyone. Statistics suggest, however, that more males cyberbully than females (13% vs. 10%). Over 8% of 12-17 year old students reported cyberbullying on more than one occasion in the past month.
What are some examples of cyberbullying?
• Sending mean or threatening texts, emails, or instant messages
• Spreading rumors or sharing secrets online
• Posing as a person and sending out cruel, untrue, or unwanted information
• Sharing an embarrassing or inappropriate photo without permission
• Making fun of someone via text, chat room, or social media
• Creating a website or profile to specifically make fun of or exclude someone
It’s important to remember that cyberbullying is ongoing and on purpose. People can be mean, can fight, and can make mistakes, none of which automatically mean they are cyberbullies. However, if the behavior is continuous and the person is aware that they are causing harm to others, then they just might be a cyberbully.
Be on the lookout for our follow-up to this blog post, where we will discuss how to respond to a cyberbully if you are victimized.
About Shannon Whitney
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Posts filed under: Q and A
Trigonometry does the trick here. Below is that line making a 42° angle with the positive x-axis. I’ve also drawn a dotted segment to make myself a neat little right triangle.
Remember that slope is rise over run—how high the line climbs divided by how far it travels right. In this case, the dotted segment labeled a is the rise and the bottom of the triangle labeled b is the run. And luckily for us, the tangent function calculates that a/b ratio! Remember your SOH-CAH-TOA. Tangent = Opposite/Adjacent.
Just use your calculator to evaluate tan 42°. You’ll get 0.90.
from Tumblr
You can make two equations here. First, you know the total number of marbles is 103, so:
The second equation is more complicated, so let’s do it in parts. First, he gives away 15 red marbles, so he should have r – 15 left. He gives away 2/5 of his blue marbles, so he should have b – 2/5b = 3/5b left.
So the ratio of red marbles he has left to blue marbles he has left (which the question tells us is 3/7) should be:
The question asks how many blue marbles he had originally, so let’s substitute and solve for b. First get r by itself in the first equation:
Now substitute that into the second equation and solve:
from Tumblr
This question comes from my own book, so my tips on how to deal with these can be found in the same chapter. The main key to getting it right is making sure you translate the words into math correctly.
Note that although the question tells you that Tariq makes brownies and Penelope makes cookies, in the end it only asks about “treats,” so we can lump cookies and brownies together.
Tariq makes 30 treats per hour and Penelope makes 48 treats per hour. Together, then, they make 78 treats per hour. We know they both worked for the same amount of hours.
The other key to getting this right is keeping track of the units of the numbers you know. In this case, we have treats and hours for units. We know the number of total treats, and we know the rate of treats per hour. We want the number of hours. How do we set up the equation we need to solve? We need to divide the total number of treats, 312, by the number of treats they made per hour, 78.
from Tumblr
One gallon of honey weighs approximately 12 lbs. If one gallon of honey is mixed with 5 gallons of water to make tea, how many ounces of honey will be in each 8 fluid ounce cup of tea?
Choices are 1, 2, 3 or 4. (Answer= 2) given: 16 oz = 1 lb, 128 fl oz = 1 gallon
Wow, that’s going to be some really sweet honeywater tea.
You’re making 6 gallons of “tea” (1 gallon honey + 5 gallons water = 6 gallons). Converting that to fl oz, you should have, in total, (128 fl oz/gallon)(6 gallons) = 768 fl oz.
Therefore, a cup with 8 fl oz is 8/768 = 1/96 of the mixture.
By weight in oz, the 12 lbs of honey you put in the mixture is (16 oz/lb)(12 lbs) = 192 oz. How may fl oz of honey will be in 1/96 of the mixture if 192 oz of honey are in the whole mixture?
(192 oz)(1/96) = 2 oz
PWN the SAT Parabolas drill explanation p. 325 #10: The final way to solve: If we are seeking x=y, since the point is (a,a), why can you set f(x) = 0? You start out with the original equation in vertex form, making y=a and x=a, but halfway through you change to y=0 (while x is still = a). How can we be solving the equation when we no longer have a for both x and y?
For everyone else’s context, here’s the problem:
Now, be careful! I am not changing to y = 0 in that algebraic solution in the back of the book; I am subtracting a from both sides! Note how the a term on the right changes from –22a to –23a.
Draw this out. Start with the two points you’re given.
from Tumblr
Start with the second equation, which tells you that t = 4.
If t = 4, then you can rewrite the first equation as follows (and solve):
4u – u = 18
3u = 18
u = 6
from Tumblr
Choice A is the only one that works.
Researchers in Australia experimented to determine if color of a coffee mug affects how people rate the flavor intensity of the coffee. Volunteers were randomly assigned to taste coffee in mugs: some white and some clear. If same type of coffee was used, researchers concluded that rating was significantly higher for those who drank coffee in clear mug. What can be concluded.
A) Color caused the difference and can be generalized to all drinkers
B)Same as A but cannot be generalized to all drinkers
Volunteers are not a random sample, so the results cannot be generalized to all coffee drinkers. There may be something different about people who would volunteer for a coffee drinking study. For example, people who would volunteer for such a study might be more likely to drink a lot of coffee and thus consider themselves able to discern subtle differences in taste.
Think of it this way: the g function is doing SOME AS-YET-UNKNOWN THINGS to (–x + 7) to turn it into (2x + 1). Of the simple mathematical operations probably at play here (addition, subtraction, multiplication, division) what could be going on?
First, the only way you go from –x to 2x is you multiply by –2. So let’s see what happens if we just multiply f(x) by –2.
–2(–x + 7) = 2x – 14
OK, so the first part’s good now, but how can we turn –14 into +1? Well, we don’t want to multiply or divide again because that would screw up the 2x we just nailed down, so why don’t we try adding 15?
2x – 14 + 15 = 2x + 1
Combine the two operations we just did (multiply by –2, add 15) and you have the g function. The function g will multiply its argument by –2, then add 15. Mathematically, we can write that like this:
g(x) = –2x + 15
Now, start from the top and make sure we’re right.
= g(–x + 7) <– substitute (–x + 7) for f(x)
= –2(–x + 7) + 15 <– apply the g function to (–x + 7)
= 2x – 14 + 15
= 2x + 1
It works! Now all we need to do is calculate g(2).
g(2) = –2(2) + 15
g(2) = 11
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I have a question on practice question 7 in “Circles, Radians, and a Little More Trigonometry.”
I solved it a different way, but I’m not sure if I was just lucky to get the correct answer. Basically, I figured that, because one radian is when the arc and radius are the same length, that radians are like proportions. So if arc RQ were equal to 6, it would be 6/6, or one radian. So then I divided π by 6 and concluded that’s how many radians it was.
Does that actually work? Or was I just lucky?
Yes, that 100% works. Nice thinking!
Practice test 8 Calculator #13
First, you can plug in on this one, so if you feel rusty on your exponent rules at all, that’s a good move. Especially on the calculator section. Say, for example, that you plug in 4 for a. Just enter it all into your calculator (you may need to be careful with parentheses in the exponent depending on the kind of calculator you have):
Now that you know x, plug 0.5 into each answer choice to see which one gives you 4.
A) \sqrt{0.5}\approx 0.707
B) -\sqrt{0.5}\approx -0.707
C) \frac{1}{0.5^2}=4
D) -\frac{1}{0.5^2}=-4
Obviously, C must be the answer.
To solve this algebraically, first start by squaring both sides. Raising a power to a power is the same as multiplying the powers, so that’ll get rid of the 1/2 on the left:
Now raise both sides to the –1 power to get a truly alone. Remember that a negative exponent is the same as 1 over the positive exponent, so you can transform the right hand side from x^{-2} to \frac{1}{x^2} to finish the problem.
A triangle’s base was increased by 15%. If its area is increased by 38%, what percent was the height of the triangle increased by?
The easiest way to get this question is to plug in! Say the base and height of the original triangle are each 10. The formula for finding the area of a triangle is A=\frac{1}{2}bh, where b and h are the base and height, so the area of our original triangle is A=\frac{1}{2}(10)(10)=50.
Increasing the base by 15% brings it from 10 to 10\times 1.15=11.5. Increasing the area by 38% brings it from 50 to 50\times 1.38=69. Plug those back into the formula to solve for the new height:
If the original height was 10 and the new height is 12, then the height increased by 20%.
Hi Mike,
Here is a really confusing question from Applerouth’s SAT text:
a = 1.5 x + 1.50
b = 1.25x + 4.50
In the system of equations above, a and b represent the cost, in dollars, of buying x buffalo wings at two different restaurants. What amount of money will get you the same number of buffalo wings at both restaurants?
A) 12
B) 19.5
C) 20
D) 29.5
The answer is A. No idea how to do this.
You have to find this by looking for the number of wings that costs the same at both stores, so set a and b (the costs at each store) equal to each other and then solve for (the number of wings that will make each store’s cost the same).
1.5x + 1.50 = 1.25x + 4.50
0.25x = 3
x = 12
Therefore, buying 12 wings at each store costs the same amount of money. The question appears to ask HOW MUCH money, so to finish the problem you need to plug 12 back in for x in either of the equations. I’ll do the first one:
a = 1.5(12) + 1.50
a = 19.50
So the answer really should be B. The answer would be A if the question asked for the number of wings that cost the same at both stores, but that’s not what the question asks.
One other note: it might make it more clear what’s going on to graph each line. What the graph below shows is that the price (on the y-axis) is cheaper at store a for up to 12 wings, but store b becomes a better deal for 13 or more wings. At the intersection point—12 wings, $19.50—the same number of wings costs the same amount at both stores.
One way to make sure you get questions like these right is to plug in some values to see which equation makes sense. For example, you might choose to plug in 0 for h here because you know that at zero feet above sea level the boiling point should be 212° F.
Choices C and D don’t give you 212 when h = 0, so they’re definitely wrong!
Now plug in 1000 for h. We should expect the right equation to do what the question says—the boiling point should be (212 – 1.84)° F = 210.16° F. Which remaining choice, A or B, does that when you plug in 1000 for h?
Choice A gives you a crazy low number: 212 – 1.84(1000) = –1628.
Choice B does exactly what you want: 212 – (0.00184)(1000) = 210.16
So the answer is B.
To get this without plugging in, you should think about the elements of the language you’re translating into math. You want to start at 212, and subtract 1.84 degrees for every thousand feet (h/1000), so you might write this to start:
From there, a little manipulation lands you on the right answer choice:
My recommendation, though: plug in. With a little practice you’ll get very fast at it, and then questions like this go from head scratchers to gimmies.
from Tumblr
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Open a PDF version to print this topic
HealthInfo Canterbury
Broken ankle (fractured ankle)
The bones of the ankle are the fibula and tibia in your calf, the lateral and medial malleolus in your ankle, and the talus and calcaneus in your footYour ankle joint is made up of four bones. The two bones of your lower leg, called the tibia and fibula, fit over your talus bone. Your talus bone sits on top of your heel bone, or calcaneus.
The most common place for the ankle to break, or fracture, is at the ends of your tibia and fibula. These are also called the medial malleolus and lateral malleolus. This often happens because you have rolled your ankle while playing sport, particularly if there is another force, such as a rugby tackle.
Breaks in the talus and calcaneus tend to be caused by a blow to the base of the foot, for example in a car accident, or a fall from a height on to a hard surface.
Your doctor will diagnose this injury by listening to your explanation of what happened, examining your ankle, and looking at an X-ray of your ankle. You might need another scan, such as a CT or MRI scan, if the X-rays are not clear.
How is a broken ankle treated?
There are different ways to treat a broken ankle, depending on where the bones are broken and what sort of break it is.
If the break is in a good position, you may be put into a plaster of Paris cast to support your ankle and stop the bones from moving while they heal.
If the bones are not in a good position or if they are unstable, you may need an operation to put them in the right position and fix them in place. The surgeon may need to use a metal rod or a plate and screws to hold your bones in place.
If the break is more complicated, you might need a metal frame around the outside of your ankle to keep the bones in the right position. Your orthopaedic surgeon will talk to you before any surgery about your options and what they plan to do.
You will be given antibiotics during your operation.
If your ankle is very swollen, you may need to wait for a few days before surgery, because the tight skin can make it difficult for wounds to heal. During this time, you will be put into a plaster of Paris backslab, which is a half cast around the back of your leg, to make you more comfortable. You will be asked to keep your leg up on pillows.
Please ask a nurse or doctor if you would like more information about your operation and recovery.
Before and after surgery you may have a plaster of Paris cast or backslab fitted to support your ankle and stop the bones from moving.
If you are older than 65, Older Person's Health Specialist Services will also see you and review your health with the orthopaedic team.
What to expect after your surgery
Your leg will be up on a pillow to help reduce any swelling. You may feel some numbness or tingling in your leg or foot, but this will eventually get better.
Your nurse will regularly check the blood flow to your injured leg. They will also check how much pain you are feeling and give you pain relief, which your doctor will prescribe. You may need to continue taking antibiotics.
You will also see a physiotherapist, who will aim to get you moving as soon as possible. This helps to prevent problems that can happen with long periods of bed rest. These can include deep vein thrombosis, infections, and muscle weakness.
Your doctor will let you know how much weight you can put on your leg. The physiotherapist will teach you how to walk with either a walking frame or crutches without putting too much weight on your leg.
Going home
Before you leave hospital a physiotherapist and occupational therapist will assess what help you may need at home and arrange it for you. You can also talk to a social worker about any worries you may have about going home.
When you leave the ward, you will be given a follow-up appointment, a discharge letter that explains what has happened to you and your treatment plan, and a prescription or medication card if you need one.
Written by director of nursing, Orthopaedic Services, Canterbury DHB. Adapted by HealthInfo clinical advisers. Page created April 2016. Last updated November 2018.
See also:
Broken bones first aid
Care of your ankle following a fracture
Communication cards in multiple languages
Living with an injury
Page reference: 132233
Review key: HIAAF-225274
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Focal Length Investigation
Night Blindness
There has been a lot of concern recently about the vision of drivers at night. It appears that drivers with good vision, or at least vision suitably correct by spectacles, become virtually blind by night. In this Activity, you will investigate possible physical (i.e. physics) causes of night blindness.
Here are some theories:
1. Less clear images are produced when light passes through larger apertures of a lens. (N.B. The pupil of the eye becomes larger as light intensity decreases).
2. Lenses have different focal lengths for light of different wavelengths so the eye does not focus light from sodium street lamps in the same way as daylight.
Choose one of these theories, design and carry out an experiment to test it. N.B. The experiment must yield quantitative results.
I have opted to do the second investigation.
To find if the theory is correct, I will find the focal length of a lens using several different colours of light. To achieve the different colours, I will use the filters and lamps in the following combinations:
1. White Bulb
2. Sodium Lamp
3. Ultraviolet Lamp
4. White Bulb with Red Filter
5. White Bulb with Green Filter
6. White Bulb with Blue Filter
7. White Bulb with Yellow Filter
8. White Bulb with Cyan Filter
9. White Bulb with Magenta Filter
To find the focal length of the lens at the different wavelengths, I will attempt to focus light going through a grid onto a white screen.
The equipment consists of a Light Source at some distance from the Filter and Object, which is at some distance from the Lens, which itself is at some distance from a Screen and the Image. The Filter and Object, the Lens, and the Screen and Image components are all placed on a ruler.
The filter will be afixed to the grid, which acts as an object. At some distance away from the object will be the light source. The distance is required to get the rays arriving in a supposedly parallel fashion (the actual distance possible is limited since intensity decreases rather rapidly as distance increases).
On the other side of the object will be the lens, and further on still will be the screen. The image of the object, focused by the lens, will be on the screen. The whole contraption is built on a ruler, allowing the relative distances to be measured easily.
To find accurate values for the focal length, I will find the distance required (from lens to screen) to focus the grid for several different object to lens distances.
Decisions and Preliminary Investigations
Preliminary investigations with the white light showed that the focal length is in the range of 0.07 cm-1. (You can see this in the white light data, since the preliminary investigations' results were combined with the main white light results).
Preliminary work also suggested that the best range of distances (for object to lens) is 20 cm to 40 cm.
After setting up the equipment as explained above, each set of readings will progress as follows:
1. Set the lens to be 20 cm from the grid.
2. Move the screen from the lens away until a perfectly focused image is formed.
3. Note the gird to screen distance.
4. Move the screen from far from the lens inwards until a perfectly focused image is formed. It is important to complete this step as well as the second since there is always a depth of field when using a lens - a small 'tolerance' in which the image is well focused. It is not as clear cut as the term focal length would have you believe.
5. Note the gird to screen distance.
6. Move the screen yet again and take yet another reading of the grid to screen distance.
7. Set the lens to 25 cm from the grid and repeat steps 2 to 6 again.
8. Repeat step 7 with distances 30 cm, 35 cm and 40 cm.
9. Change the filter and/or lamp and repeat steps 1 to 9 for this new wavelength.
10. Repeat step 10 for all remaining lamp/filter combinations.
Object Distance
The distance between the object (the grid) and the lens. cf: Image Distance.
Image Distance
The distance between the image (the screen) and the lens. cf: Object Distance.
Focal Length
The principal focus (F) of a thin lens is the point on the principal axis towards which all paraxial rays parallel to the principal axis converge (in the case of a convex lens), or from which they appear to diverge (in the case of a concave lens), after refraction.
Since light can fall on either surface (front or back) of a lens, lenses have two principal foci, one on each side. These are equidistant from the centre (P) of the lens (provided the lens is thin and has the same medium on both sides, e.g., air).
The distance FP is the focal length of the lens.
In equations, u represents the object distance and v represents the image distance. The third variable, f, represents the focal length of the lens.
The object distance, u, the image distance, v, and the focal length, f, are related by the equation:
+ 1
= 1
A quick way of measuring f is to measure the image distance required to focus a distant object. This works because if u is large, u-1 is small and so cancels.
+ 1
= 1
» 1
and this leaves
v » f
I will not be using this technique since it is not accurate enough.
The technique I will be using, which is described above, is somewhat more accurate and involves finding values of u and v, and using the equation to calculate f. There are three variations on the calculation of f by this method (the experimental steps are the same in all cases, although more data is required for the more accurate calculations).
1. Find one pair of values (one u and one v) and simply calculate f by using the equation
+ 1
= 1
2. The second method is to take several pairs of u and v and average the resulting fs.
3. The third and best method is to take even more data and to plot it. Hopefully (and theoretically) the x-axis intercept and the y-axis intercept should be equal. This is easily proved. Starting from the equation
+ 1
= 1
we rearrange into the y = mx + c form,
= -1
+ 1
Where y is equivalent to u-1, m is equivalent to -1, x is equivalent to v-1, and c is equivalent to f-1. Since the gradient, m is equal to -1, at u-1 = 0 (y = 0)
0 = -1
+ 1
which rearranges to
= 1
And at v-1 = 0 (x = 0)
= 0 + 1
which cancels down to
= 1
Very clearly then, the best fit line of the plotted data should result in a line of gradient -1 which crosses the x- and y- axes at the same point.
I have opted for the more time consuming third option.
Based on research and past experience, I would suggest that the theory proposed in the brief is indeed correct. It is my belief that as the wavelength shortens (blue end), the focal length will decrease, and as the wavelength increases (red end), the focal length will get longer. This is because waves of different wavelengths are refracted by different amounts in the same material (same principle as for a prism splitting white light) and the blue light is bent more than the red light upon entering and exiting the lens.
It will be interesting to see what happens with cyan, since it's filter lets through two distinct wavelengths at opposite ends of the visible light spectrum (see results section).
Wavelengths of lights used 1
Light Source or Filter Wavelengths (nanometres)
White 400 - 700
Sodium 589.00, 589.59
Ultraviolet 404.7
Red 700
Green 525
Blue 450
Yellow 550 - 700
Cyan 675, 400
Magenta 400 - 550
All the results in the results tables and graphs are in centimetres. Technically, I should have converted my centremetre readings into metres, however, in this case it makes little difference.
There are nine tables, which give all the data (one sheet per lamp/filter combination).
There are also twelve tables, one for each combination (all using the same scales), one for white light (to show all the data I used different scales on this graph) and two final results summary graphs (one plotting f-1, in cm-1, and one plotting f, in cm)).
Skew Results
Light Source or Filter Skew cm- 1
White 0.001
Sodium 0.006
Ultraviolet 0.006
Red 0.006
Green 0.006
Blue 0.006
Yellow 0.001
Cyan 0.001
Magenta 0.008
The data was surprisingly nice. There was one slightly abnormally high value in the blue data, a very wrong data point for the ultraviolet lamp (probably a transcript error, that is, I probably mis-noted the data during collection) and one slightly low value in the yellow data. All the other data seemed fine.
To calculate the errors, I plotted the data then drew two best fit lines: one above the data and one below. I found that actually, the gradient wasn't exactly -1. Examination of my equipment suggested that a possible reason for this is that my lens was not actually exactly above the point I was measuring each time. Indeed, I collected the data in three sets and within each set all the data has the same skew. This seems to indicate that it is experimental error.
In the case of magenta, the skew is also probably due to the large - huge - range of wavelengths involved.
What I am calling skew is the difference between the x-intercept and the y-intercept (in cm-1).
The error margins were in the order of 0.001 to 0.007 cm -1. Magenta had the biggest error range, which is to be expected since it also had the largest skew and the largest wavelength spread. White light was next, which again is normal, since it has a wavelength spread of the whole visible light spectrum.
Errors in Best Fit Lines
Light Source or Filter ± Error cm- 1
Magenta 0.0071
White 0.0046
Blue 0.0024
Green 0.0021
Yellow 0.0020
Sodium 0.0019
Red 0.0016
Cyan 0.0015
Ultraviolet 0.0012
What is surprising is that Blue and Green light were next (note, however, that they have a much smaller error - only Magenta and White have considerable error margins). The blue error margin actually enables the "wrong" data point to be "correct" since it's error bars are within the best fit lines.
The Results Summary graphs show the trend well. They are a plot of the focal lengths of each of the filters, against the wavelengths of the filters (when I say filters, read lamps and/or filters really). There is a definite trend, as the wavelength increases, so does the focal length. Luckily for me, this is as I predicted. Three things are of note however.
1. Cyan was an interesting case, I could not really understand it's pattern. This was effectively a mixture of two other filters (blue and green, theoretically) so it is not surprising that there is no obvious trend.
2. Yellow was a wide band of wavelengths, but unlike Magenta (which is also a wide band) it didn't fit into the general pattern.
3. Sodium seems to have "missed" the trend. This is odd as Sodium should have been a very accurate part of the experiment (it has very definite lines (it's D-lines) as it's wavelengths). I would have expected it's focal length to be about 0.1 to 0.2 cm longer.
The summary graphs do not pretend to be accurate (I have merely placed the labels on the graph, not dots) because the error bars are so relatively large that this is the only way to accurately portray the information.
The theory I put forward in the prediction matches the facts. I can therefore conclude that it is the correct one until such time as contradicting data is discovered or these results are reinterpreted.
If you recall, I suggested that the theory proposed in the brief was indeed correct. It seems that as the wavelength shortens (as in the blue end of the visible light spectrum), the focal length decreases, and as the wavelength increases (as towards the red end of the visible light spectrum), the focal length gets longer. This is probably because waves of different wavelengths are refracted by different amounts in the same material (as I said in my prediction, this is the same principle as for a prism splitting white light) and the blue light is bent more than the red light upon entering and exiting the lens.
As always, time was an important factor limiting my work. The other factor was that the point at which something is focused is quite subjective and dependant on the user's eyesight. During the course of the experiment I asked some of my colleagues to see if they thought my screen was focused and their opinions varied.
The experiment would seem to indicate that Sodium lamps are not the best invention as far as good night road lighting goes, although this is not entirely true. After all, human eyes can accommodate to the required focal length as needed. We do it all the time, to look at distant objects or close ones. If one is perfectly honest, the difference in focal length is actually negligible (around half a centimetre over the whole of the visible light spectrum).
Further Research
Obviously it would be interesting to investigate the first of the two experiments suggested. It would also be interesting, in my humble opinion, to find out if there is a way of objectively ascertaining is something is focused or not. That way, the exact range could be found automatically by computer and a much more accurate study with greater emphasis on the quantitative results could be achieved.
PHYSICS A Textbook for Advanced Level Students
2nd Edition (1987). Author: Duncan, Tom. Publishers: John Murray (Publishers) Ltd. ISBN: 0-7195-4336-3
Philip Harris Catalogue (1)
This resource contained the transmission charts from which I found the wavelengths for the various filters I used.
Internet Explorer 4.01
I used IE4 for the publishing of this document. The standards I used were HTML4 and CSS2, created by the World Wide Web Consortium.
EMACS (text editor)
GNU Emacs 19.34.6 (i386-*-nt4.0) of Thu Sep 25 1997 on ESME. Used for editing this document.
Quattro Pro 6.1
For the graphs and spreadsheet I used QPW6.
All pictures are supplementary to the text, which describes all information contained within the pictures fully. Note. CSS support (aka, IE4) makes a huge difference to this page. I have used <i> to mean instance of use as discussed on my Internet Projects page.
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• CCB Science pages 102 - 109
• Define symbiosis
• Describe mutualism, commensalism, and parasitism
• Give real-world examples of each type of symbiotic relation ship
Key Concept
• The term symbiosis describes specific kinds of relationships between organisms in the same environment.
Tier 2 host
Tier 3 antibodies
Test Words summarize
Evidence-Based Reading
• Word Parts: Write the word symbiosis on the board. Underline the base word bios. Explain that its history is Greek, and means one’s life, or way of living. Next, explain that letters attached to the beginning and end of a base word, or affixes, change the meaning of the word. Letters attached to the beginning are called prefixes. Circle the prefix ‘symand’ explain that it means together. Explain that letters attached to the end of a word form a suffix. Circle the suffix -is. Explain that it most closely means having the character of. Ask students to use their understanding of the word parts to define the term symbiosis.
21st Century Skill
• Critical Thinking and Problem Solving: Invite volunteers to talk about the university website they researched. Have students identify their chosen universities and describe the kinds of science investigations that are being conducted there. Ask them to state the hypotheses university scientists are studying and the methods they’re using. Encourage students to talk about the investigations that most intrigue them.
Writing Practice
• Remind students to think through the different kinds of symbiosis before writing. Students should describe the interaction of the mother and the puppy before identifying the kind of symbiotic relationship the two share. Mothers and offspring have a parasitic relationship, as developing fetuses and newborns depend on the mother for resources, leaving fewer resources for the mother.
Before Lesson
This lesson requires students to be familiar with biotic and abiotic factors in the environment. To determine their readiness, write the words living and nonliving on the board. Ask students to describe some of the living and nonliving things they see around them. Record their responses on the board. Then have students go beyond the classroom to consider spaces on the school campus. Continue adding students’ examples to the lists on the board.
Explain to students that in any ecosystem, living things interact with each other and with the physical environment. These organisms are constantly competing for resources, such as food, water, and shelter. Organisms live symbiotically, or with other living things. The relationships that organisms share may benefit both, harm one organism, or help one while having no effect on another. Ask students to think of examples of familiar symbiotic relationships within a family, such as a parent and child or two siblings. Invite students to talk about how the two members of those relationships interact and help or benefit one another.
Guided Practice
• Interactions Among Living Things
• Mutual Symbiosis
• Termites and Bacteria
• Acacia Trees and Ants
• Ox-peckers, Rhinos, and Zebras
• Humans and E. coli
• Parasitic Symbiosis
• The Tick
• The Tapeworm
• Commensal Symbiosis
• The Pseudo-scorpion and Beetles
• Cattle Egrets and Livestock
• Sharks and Remoras
Core Skill
Identify Hypotheses: Read the sidebar text aloud. Give students time to consider the scientists’ observations of the acacia trees and form hypotheses. Invite students to share their ideas. Record their ideas on the board. (Acacia trees do not have a mutually beneficial relationship with the different kind of ant.)
Summarize Text: Remind students to think about what, why, and how as they reread their summaries. Tell them to be sure these three questions are addressed.
Summarize and Illustrate: Organize students into small groups. Have students reread different sections of the text aloud (“Mutual Symbiosis,” “Parasitic Symbiosis,” and “Commensal Symbiosis”) and explain what they have read in their own words. Have them select one section to label and illustrate.
Hypothesize and Propose an Experiment: Have students review the lesson and the organisms mentioned in it. Invite students to choose an organism, ask a question that can be answered through an investigation, form a hypothesis, and propose an experiment. You may want to ask students to write their hypotheses and proposals.
Lesson Review
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Feature - NetLogo: A low threshold, no ceiling language
Feature - NetLogo: A low threshold, no ceiling language
Two fifth grade students use NetLogo to learn about electrical current. Image courtesy Pratim Sengupta.
Front page image: Tiling with squares whose sides are successive Fibonacci numbers in length. Courtesy Wikipedia under Creative Commons license.
Elementary school students may not be able to decipher mathematical models such as Maxwell's Equations. But given the right visualization and computational modeling tools, they can learn the underlying concepts.
Meet NetLogo, a multi-agent programmable modeling environment authored in 1999 by Uri Wilensky, a learning sciences and computer science professor at Northwestern University, and founder of the Center for Connected Learning and Computer-Based Modeling.
Remember the turtle?
A generation of adults were introduced to functions and programming through Logo and the "turtle" - an on-screen triangular cursor - that accompanied it. Logo was first created in 1967 by Wally Feurzeig and Seymour Papert at MIT.
The first Logo implementation, Ghost, was written in LISP. But this functional programming language's intellectual lineage can be traced back to such areas as artificial intelligence, mathematical logic, and developmental psychology.
Wilensky's NetLogo takes the familiar language to a new level, blending Logo with StarLisp. StarLisp was in turn conceived by Cliff Lasser and Steve Omohundro in 1985 at Thinking Machines Corporation, for use on the company's supercomputers.
"While in Logo, you can only give commands to program the behavior of a single turtle, in NetLogo, you can create as many turtles as you want, and give them commands to model emergent patterns that arise from the interactions between these agents," explained Pratim Sengupta, a learning sciences researcher at Vanderbilt University.
Sengupta, pictured above, is an assistant professor in the Teaching and Learning department at Vanderbilt University, and the director of the Mind, Matter and Media Lab. Here he demonstrates a NetLogo simulation that shows students magnetic field lines. Image courtesy Miriam Boon
From supercomputer to school laptop
Today, NetLogo is in wide use by researchers in the natural and social sciences, according to Wilensky's biography, and it comes equipped with models in other domains, such as economics, biology, physics, chemistry, psychology, and system dynamics, to name a few.
Sengupta's group is using NetLogo to study how students learn about complex mathematical and scientific concepts.
To understand electricity from a microscopic perspective, for example, higher-level physics students traditionally use their knowledge of differential equations and integrals.
"That's real easy at the level of a Ph.D. student, but inaccessible to a fifth grade student," Sengupta explained. "Fifth graders don't know algebra very well. They don't have a handle on what rates are. They don't know what calculus is."
That's where the educational models and modeling labs built in NetLogo by Sengupta's team come into the picture.
"What the labs do is they show the aggregate level behaviors of electric current as emergent from simple interactions between many individual objects such as electrons and ions," Sengupta said. "This is a computational narrative of what's going on, which is both generative and intuitive."
So far, Sengupta has conducted trials with over 500 fifth, seventh, and twelfth grade students from several different US schools, and researchers in Singapore and Australia are now using NetLogo in ninth through twelfth grades in several schools. All of these studies support the theory that younger students can develop fairly sophisticated forms of scientific thinking and reasoning through bootstrapping their intuitive knowledge - a theory that contradicts the dominant school of thought that has shaped science curriculums around the world.
Sengupta and Wilensky's work goes beyond providing evidence that could overturn what we thought we knew about teaching science, however. It also identifies a mechanism through which students with no previous exposure to mathematically advanced science can gain an intuitive grasp of aggregate behavior on a microscopic level. And in the process, it leaves behind a tool that novice learners at various ages can use to learn about electricity.
What next?
Sengupta hopes to re-examine and push the limits of what students can learn across several domains such as physics, environmental literacy and evolution, by iteratively building and empirically testing more generalizable versions of the cognitive model of naive intuitions on which he has been working on over the past few years. He is also working on creating more agent-based computational programmable toolkits and learning environments that can support longer-term learning progressions, spanning several years.
-Miriam Boon, iSGTW
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By David F. DiMeo
Using Arabic for numbers and counting can be a bit tricky if you need to work extensively with numbers, such as in mathematics and accounting. Arabic number can be confusing because the rules change depending on how the numbers are being used.
To make things easier, take a look look at just the most common usage — without worrying about the more advanced rules for case and gender. Even native speakers often default to a simplified form for numbers, except in the most formal situations.
The numbers you’ll use the most often are those between 1 and 20.
1 to 20
waaHid 1
Ithnaan 2
Thalaatha 3
arbaa 4
Khamsa 5
Sitta 6
saba 7
Thamaaniya 8
tisa 9
ashara 10
aHad ashar 11
ithnaa ashar 12
thalaathat ashar 13
arbaat ashar 14
khamsat ashar 15
sittat ashar 16
sabat ashar 17
thamaaniyat ashar 18
tisat ashar 19
ishriin 20
The numbers from 21 to 99 are formed by saying the ones digit first, then wa (and) followed by the tens digit. For example, waHid wa ashriin (21 [literally: one and twenty]).
21 to 99
waHid wa ishriin 21
ithnaan wa ishriin 22
thalaathiin 30
waHid wa thalaathiin 31
ithnaan wa thalaathiin 32
arbaiin 40
khamsiin 50
sittiin 60
sabiin 70
thamaaniin 80
tisiin 90
You should read Arabic numbers in the same order as English numbers, from the largest to smallest place, except for the ones digit, which comes before the tens. So 1964 would be read “one thousand, nine hundred, four, and sixty” or alf tisa mia arba wa sittiin.
100 and higher
mia 100
mia wa waHid 101
mia wa ashara 110
mia wa khamsa wa khamsiin 155
miataan 200
thalaath mia 300
arba mia 400
khamsu mia 500
sitta mia 600
saba mia 700
thamaanii mia 800
tisa mia 900
alf 1,000
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Week 6
Class 1
Monday, Oct. 15. Supervised by Ms. Healey.
Topics covered:
• WebAssembly
• WebAssembly is the techniques behind three.js, the library we will build our final project upon. It can speed up the process of rendering dramatically.
• Texture Mapping
• Texture mapping, as the name suggests, is the technique people use to render the texture of an object.
We have read the following articles
We spent most of this class discussing rendering techniques and what library is the best for our final projects. Some of the libraries we discussed inlcude OpenGL, WebGL. In addition, we have discussed how the browser works and how an image is created on a computer. Usually, this process is done using some sort of library so the details are abstracted out to designers and programmers. However in essence the process requires the communication between GPU and software to even render a simplest window. Through the medium of WebAssembly, we are able to communicate almost directly with GPU and CPU without too much computational overhead. In the end, we have decided to use three.js for its simplicity to implement and its wide availability, as well as its indecency of additional software installation.
Class 2
Wednesday, Oct. 17.
This class, we continue to work on texture mapping.
We have watched this lecture in class:
We have watched this lecture for homework:
The importance of texture mapping is that it reflects the surface of an object, which is all an end user can see. Texture is the deterministic factor of how real an object looks. An object that lacks texture will be perceived as unreal, even though people are able to relate the object to real life objects. The most extreme expample of lack of texture is stick figures or cartoons. They have correct shapes in general, however they are obviously unrealistic because they lack of texture –– they are simply a huge block of colors. A realistic object on screen, such as a photograph, would have very detailed serface, such as a gradient of change in highlight in accordance to the reflectance of the object. Reflectance, or how smooth the surfaces of the object are, is all texture mapping is about. The end goal is to model mathamtically, as well as construct programatically, the surface of a given object as close as possible while taking a moderate amount of time to compute.
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Tract 22d
The Story of the Change of the Sabbath
- Supplement to Lesson 22
There have been seven days in the week from time immemorial. We can read the Bible from Genesis to Revelation and we will only find Seventh-day Sabbath worship. There is nothing about first-day worship in the entire book. Where then did it come from?
In order to discover the origin and growth of worship on the first day of the week, we must look outside the Bible--into the pagan world of Christ's time. In fact, to locate the origin of "Sunday," we must look to the same source. For first-day sacredness, and the very name Sunday come from the same place.
The Planetary Week
The various days of the week were in ancient times called the first day, the second day, etc., for these were their Biblical names. But about the time of Christ they were given new names. The non-Christians began calling them the day of the sun, the day of the moon, etc., in honor of different heavenly bodies. This was known as the "planetary week."
Each day was ruled over by a different god, but the most important of all gods was given the rule of the first day of the week, with the idea in mind that the first is always more important than that which follows it. The most important of all gods was given the rule over the first of the seven days. It was his day, the day of the Sun, and all the worship of the week centered on his day.
Now, although these names for the days of the week were new, the sun god wasn't, for his worship came from a devotion to that most powerful of natural objects. It was one of the most ancient forms of worship and is represented by solar disc images found on nearly every continent of our world.
"Sun worship was the earliest idolatry."--Fausset, Bible Dictionary, page 666. The Arabians appear to have worshiped it directly without using any statue or symbol (Job 31:26-27). Abraham was called out of all this when he went to the promised land. Ra was the Sun god in Egypt, and On (Heliopolis) was the city of Sun worship (see the Hebrew of Jer. 43:13). Entering Canaan under Joshua, the Hebrews again met Sun worship--Baal of the Phoenicians, Molech or Milcom of the Ammonites, and Hadad of the Syrians, and later the Persian Mithras or Mithra. Shemesh was an especially important Sun god in the middle east, and, later, in Egypt Aton was the god of the Sun Disc. The temple at Baalbek was dedicated to Sun worship.
By associating with Sun worshipers, the Israelites frequently practiced it themselves (Lev 26:30, Isa 17:8). King Manasseh practiced direct Sun worship (2 Kg 21:3,5). Josiah destroyed the chariots that were dedicated to the Sun, and also removed the horses consecrated to Sun worship processions (2 Kg 23:5,11-12). Sun altars, and incense were burned on the housetops for the sun (Zeph 1:5). and Ezekiel beheld the "greatest abomination": direct Sun worship at the entry way to the temple of the true God. This was done by facing eastward to the rising sun. (Ezek 8:16-17).
All this time there was no particular day that was used for this heathen worship. But then, about the time of Christ, or a little before, the various days of the week were dedicated to specific pagan gods--dies Solis--the day of the Sun, dies Lunae--the day of the Moon, and so on.
The sacred day of the Jews and Christians was the memorial of Creation--the true Sabbath--the Seventh day--the only Sabbath given in the Bible. The sacred day of paganism was the memorial of the Sun-god--the first day of the week. His day was called, "the Venerable Day of the Sun."
As we have seen in other tracts in this series, Sunday-keeping never occurred in the Old or New Testament, nor was it commanded. In the time of Christ and the Apostles, the official religion of the Roman government did not have a sacred day, but gradually Sunday-keeping began to become common among the non-Christian people of the empire.
The planetary week, each day named after a different planet in the sky, played a very important part in the worship of the sun. By the time of Christ, Sun worship was most powerfully represented in Mithraism. Now, Mithra (or Mithras) was originally an ancient god of Iran, and had been worshiped as the god of strength and war by the descendants of the Persians. But by the first century A.D. he had been transformed, oddly enough, into the leading sun god, and the foremost pagan god of any kind, of the western civilized world. The Romans often called him by a new name, Sol Invictus, "the Invincible Sun." During the early centuries of the Christian Era, Mithra was the greatest pagan rival of Christianity.
And this was not without a carefully developed plan, for Satan had arranged that this religion would closely approximate in several ways the only true religion in the world--Christianity. It had such features as a dying, rising Saviour, special religious suppers, a special holy day out of the weekly seven--the Sun Day, initial baptism of its converts (in the blood of a slaughtered bull), and other similarities. It counterfeited the religion of the true God more cleverly than any other religion up to that time in history.
Gradually, large numbers of non-Christians began observing Sunday as a holy day in honor of Mithra. He was especially liked by the Roman soldiers, for his worship included athletic feats of skill and "warlike manliness."
When Augustus Caesar became emperor, just before the birth of Christ, Mithraism was already spreading westward from Asia into Europe, and into the Roman Empire.
Since the Roman generals, in times of crisis, frequently took over the emperorship, this also favored the growth of sun worship. (Two centuries later, the Roman generals Constantius Chlorus and his son Constantine were devoted to the Sun god. This would prove very significant, as we will see later on.)
But, in the first century, and the first part of the second, many of the non-Christians in the empire were also keeping the Seventh day. They were attracted to the Seventh-day Sabbath, because of Jewish, as well as Christian, influence. Josephus, a historian who lived in the first century, remarks on how widespread throughout the empire was the keeping of the Seventh-day Sabbath at that time.
Anti-Semitic Reaction
But then two important events occurred that shattered all this. In A.D. 70, nearly forty years after the death of Christ, and then again in A.D. 135, serious Jewish revolts were put down with much bloodshed. As a result of this, the hatred of the Romans toward anything that savored of Judaism became intense. Hadrian, the emperor, issued an edict soon after, strictly prohibiting the observance of the Seventh-day Sabbath. But imperial decrees tended to be short-lived, and Christians generally disregarded it. However in Rome itself, the capitol of the empire, things were different.
Anicetus, the local bishop, or religious leader, of the Christian church in the city of Rome (men today would call him the "pope"), urged his followers as well as neighboring churches to keep the first day instead of the Seventh.
At the risk of his life, the aged Polycarp, who had been a close friend of the Apostle John before his death about 100 A.D., traveled to Rome about the year 155, and strongly protested this action on the part of Anicetus. The Roman bishop refused to yield to Scripture in this matter, but otherwise the meeting was courteous. Polycarp returned to Smyrna and was martyred the next year.
Second Century Mithraism
By the middle of the second century, Mithraic Sun worship was very popular among the Romans. The emperor Antoninus Pius (138-161 A.D.) erected a temple to Mithra at Ostai, a seaport town a few miles below Rome. Pius' name is also written at the base of the famous temple of the Sun at Baalbek (Heliopolis) in Syria. Justin Martyr, a leading Christian writer at the time, wrote an open letter to Pius, in which he referred several times to the increasing influence of Mithraism in the Christian Church. By this time, Mithraism was becoming popular among the Christians at the Theological Seminary in Alexandria, Egypt.
Gradually, the worship of the Invincible Sun became even more popular and widespread among the Roman Empire. Emperor Aurelian (270-275 A.D.), whose mother was a priestess of the Sun, made this solar cult the official religion of the empire. His biographer, Flavius Vopiscus, says that the priests of the Temple of the Sun at Rome were called pontiffs. They were priests of their dying-rising Saviour--Mithra, and vicegerents in religious matters next to him.
By this time, the middle of the second century, worldly Christians apparently, from the records in Alexandria and Rome more than anywhere else, in order to be better accepted by their pagan neighbors, began keeping Sunday, and in order to excuse their practice, since it was not Scriptural, they called it "the Lord's Day" even though it was obvious to all that Revelation 1:10 said nothing about Sunday.
Then the ball bounced back. Picking up this idea from the worldly Christians, the followers of Mithra began calling their Sunday, the day of Mithra, "the Day of the Lord," and their god, Mithra, "Lord." This led to Emperor Pius' official declaration that the deity--Mithra--was to be called Sol Dominus Imperil Romani ("The Sun, the Lord of the Roman Empire"). This title and the name Sol Invicto appeared together on his coinage.
Most of the "new things" that entered the church in the early centuries originated in Alexandria (Egypt) or Rome (Italy), and from those two locations they gradually spread to many of the western churches, and thence to some of the eastern ones. Until the fourth century and some time beyond, the eastern churches, being farther from Rome, tended to remain closer to the teachings of the Apostles.
Sun worship continued to be the official religion of the empire until Constantine 1 defeated Licinius in 323, after which it was replaced by Romanized Christianity.
Sunday and Christianity (50--300 A.D.)
It may seem surprising that any Christians before the time of Constantine would keep Sunday instead of the Biblical Sabbath--the Seventh-day Sabbath commanded by God Himself. But a clearer understanding of what was happening within the Christian church itself will explain this. Christ was crucified in 31 A.D. Most of his disciples were gone by 65 A.D. John, the last of the Apostles, died just before 100 A.D.
By the year 200, pagan compromises and practices were beginning to come into the church in a decided way. Of course, the safety of God's people then, is our only safety now: The Word of God--nothing less, nothing more, nothing else. But friendship with the world was a pleasant thing and brought many rewards. By 250, tides of worldliness were sweeping into the early church in an amazing flood. Occasionally persecutions would arise which would purify the church, but then as soon as peace returned, the world returned with it. This tendency to compromise and worldly ideas was especially noticeable in the urban areas of Egypt and the western part of the Empire.
Here are some of the non-Scriptural changes that were coming into the Church at this time, primarily through the influence of Alexandria or Rome:
The December 25 Birth
Cumont, Olcott and others clearly show that December 25 was the yearly date of the annual birth of Mithra the Sun god--the leading heathen deity of the Empire. On this date, his followers celebrated the fact that the visible orb of the sun was again rising higher in the sky, following the winter solstice (December 21st, when it is the lowest). His birth-date was made an official holiday in the Empire by Aurelian about 273 A.D.
The Roman church being more liberal than most, the Christians there began celebrating this date as the birth-date of Christ not too long after this. The December 25 celebration came into the Christian Church from the local church at Rome, which received it directly from paganism.
"December 25 was a great pagan festival, that of Sol Invictus, which celebrated the victory of light over darkness and the lengthening of the sun's rays at the winter solstice. The assimilation of Christ to the Sun god, as Sun of Righteousness, was widespread in the fourth century and was furthered by Constantine's legislation on Sunday, which is not unrelated to the fact that the Sun god was the titular divinity of his [Constantine's] family."--Williston Walker, A History of the Christian Church, third edition, page 155.
This midwinter pagan holiday was eventually declared to be the solemn anniversary of the birth of Christ--the mass of Christ.
Tonsure and Holy Water
Because pagan priests cut a circular bald spot on top of their heads in honor of the solar disc, Christian leaders of Alexandria and Rome soon copied this hair style, the tonsure. [Read Lev 21:5, and Deut 14:1]. It is still used by certain monastic orders to this day. Along about this Lime, six called "holy water"began to be used for baptism, which itself soon degenerated into a mere sprinkling instead of immersion. [Ac 8:35-38; Rom 6:3-5].
The Queen of Heaven
Much of the basis of later Roman Catholic liturgy originated at this time, with the direct copying by the Alexandrian and Roman churches of the Egyptian worship of Isis, the Egyptian Queen of Heaven. [Jer 7:18; 44:17-19,25]. Here is how the Egyptian Mother goddess and her Child were worshiped:
The Sacrificial Ritual
"The daily ritual of Isis, which seems to have been as regular and complicated as that of the Catholic Church, produced an immense effect on the Roman mind. Every day there were two solemn offices, at which white-robed, tonsured priests, with acolytes and assistants of every degree, officiated. The morning litany and sacrifice was an impressive service. The crowd of worship pers thronged the space before the chapel at the early dawn. The priest ascending y a hidden stairs drew apart the Vail of the sanctuary, and offered the holy image to their adoration. He then made the round of the altars, reciting the litany [mystic words in an unknown tongue], and sprinkling the holy water from the secret spring."--Samuel Dill, "Roman Society from Nero to Marcus Aurelius." page 577-578. London, Macmillan, 1904. [2 Tim 2:15-16, Ex 20:3-5].
The Mother and Child
The "Queen of Heaven, the Mother of God" concept came directly into the Christian church from the Mother and Child Cult in Egypt--the worship of Isis and Horus. When this new idea came into the Christian church through the local church at Rome in the fourth century, it really shook up the church. It came as a result of the urging of Egyptian church leaders who declared Mary to be "the Mother of God." This caused a split in the church and the banishing of Nestorius, a Christian who tried to oppose it. Images--statues--of Isis nursing Horus at her side had already been accepted by pagans all over the empire, for she was the avowed patron goddess of sailors from Italy. But then in the fifth century a very significant thing happened: The names "Isis and Horus" totally disappeared, and in their place appeared the worship of "the Virgin Mary and her Child." [Mark 3:31-35, Luke 11:27-28, Matt 10:37]
It is interesting to note that the very same thing happened to Mithra. Just as soon as the essential aspects of Mithraism had been brought officially into the church, Mithra the greatest pagan god of his time--disappeared within a century! Satan no longer needed it for his purposes--for he had already brought both him and his day into the Church. And actually Mithraites no longer needed it either. Christianity, in its new form, now supplied its place very well.
Soon the church was reaching out to still other lands for ideas to make its rituals and teachings more varied and imposing.
Hermits and beads and Candles
From India, came ascetics, monastic hermits, and rosary beads. The burning of candles came from the worship of Mithra, the Sun god [the light in the candle flame was considered a small "sun"] All these things entered as the Christian church, led by the Theological School at Alexandria and the Bishop of Rome opened its doors to heathenism. And, of course, with these new practices, and from the same sources, Sunday observance came into the church.
Easter--the Resurrection of Spring
In the time of the apostles there was no Easter service such as we have today. The early church kept the day of the Biblical Passover (Pascha), but not Easter, which was but another invention of paganism. Now Easter also came in the spring of the year, but it was a pagan fertility festival in honor of Ishtar, also known as Attis and was accompanied by licentious practices. Emperor Claudius made it an official holiday during his reign.
The issue here is the fact that Christians began keeping a pagan holiday sacred to an ancient and well-known goddess, and a licentious one at that. Cumont tells us: "Attis awoke from his sleep of death, and the joy created by his resurrection burst out in wild merrymaking, wanton masquerades, and luxurious banquets. "--Franz Cumont, Oriental Religions in Roman Paganism, pages 56-57, 1907 edition.
Gradually the Christian church identified with this pagan festival of the Resurrection of Spring, by keeping it in honor of the resurrection of Christ. History reveals that it was a deliberate decree of the bishop of Rome that brought Easter into the church.
About the year 154 A.D., Anticetus, bishop of the church at Rome, authorized a Sunday festival to correspond with the Attis fertility festival. This was a combining of Mithra, Attis and Christ and would better appeal to the heathen, he thought. Half-converted theologians in Alexandria spent their time digging up pagan philosophy and recommending it in writing to the Christian churches of the Empire, while half-converted church leaders in Rome used those ideas as levers to gain control over the other local churches by pretending that they had the authority to require obedience to them!
Polycarp who was a close friend of the Apostle John before his death, at the same time mentioned earlier in which he tried to win Anticetus back to the true Sabbath, also tried to dissuade him from keeping the pagan Sunday Easter festival. But he failed in his efforts and returned with a sad report to the brethren in the eastern churches.
First Sunday Coercion
Then, in 195 A.D., for the first time in history the Roman church made major news in all the churches of Christendom, when Victor, bishop of Rome, tried to force all of the eastern church leaders to keep the annual celebration of Christ's resurrection on Sunday. Of course, the bishops of the other churches protested, insisting that if done at all, the Biblical precedent for this was on the fourteenth day of the month Nisan [Ex 10,12,14, Lev 23:5].
But Victor would not consider this, and had the boldness to write letters "ex-communicating" all leaders and churches that refused to do as he said. He declared all the churches of Asia to be apostates because they would not follow his example in the matter.
Back in those days, some churches were more influential than others, but none were "over" the others. What Victor tried to do in 195 AD. bordered on the fantastic.
This was probably the first time in history that the bishop of Rome attempted to gain control over all the other churches, and commenting on it, Dr. Bower, in his History of the Popes, volume 1, page 18, calls it "The first essay of papal usurpation." In simple language, we would call it, "the first attempt at papal takeover."
A careful study of the historical records reveals that gradually, with the passing of the years, the Roman bishop tended to use his new day, Sunday, as a ploy for political supremacy over the other churches. Victor's decree was the first ecclesiastical Sunday Law of any kind, in history.
The Easter Controversy continued, with the Eastern churches giving it stiff opposition until the Council of Nicaea in 325 A.D., at which time Sunday was declared the official day for Easter observance. Emperor Constantine immediately followed this, the same year, with civil enactments enforcing it among the churches.
Origin of Christian Sunday keeping
It was through the Gnostic Christians of Alexandria that several serious problems entered the church:
1--Spiritizing away Scripture truth through the use of allegories
2--The use of images and image worship in Christian worship
3--The introduction of Greek philosophic speculations into the church
4--The practice of Sun Worship
5--The keeping of Sunday
6--The introduction of Egyptian pagan rituals
7--Anti-Jewish sentiment
8--The founding of the first worldly seminary for the training of ministers (a school, by the way, that continued with great success for centuries).
Only the church at Rome gave full support and backing to the marvelous innovations of Alexandria, and it is a striking fact that all the Christians for the first two centuries after Christ and the Apostles, whose writings have been authenticated beyond question, and who opposed the Sabbath and favored Sunday observance, were men who (1) were sympathetic with Gnosticism, had anti-Jewish prejudice, and (2) came from or who received their training in Alexandria or Rome.
Outstanding among these were the Gnostic Christian philosophers, Justin Martyr, Clement of Alexandria, and Origin. And with them, Tertullian, who, living west of Alexandria, received his training from a pagan skeptic (instead of gnostic) philosopher, before professing Christianity.
The only other significant and authenticated Christian writers who taught Sunday keeping before 300 A.D. were the bishops of Rome, in their decrees and writings.
Gnostic Philosophy
Now, unless you have actually read their writings you cannot imagine what kind of thinking went through the minds of these "Christian philosophy" men of Alexandria. It is nearly unbelievable--the mystical dreamy applications they put on Scripture and on everything else. And yet these are the men who began the Sunday-keeping idea in the Christian church, and then passed it onto the politically oriented, but liberal, minds of the leaders at Rome.
As an example, here are two of Clement of Alexandria's most important statements about Sunday-keeping. It should be here mentioned that Clement was head teacher at the Alexandrian theological school for several years (190-215 A.D.), and has the distinction of being the first Christian in recorded history to apply the term "Lord's day" to the first day of the week. Here are two of his most important passages on the importance of Sunday-keeping:
"And the fourth word [in the Ten Commandments] is that which intimates that the world was created by God, and that He gave us the seventh day as a rest, on account of the trouble that there is in life . . . The seventh day, therefore, is proclaimed a rest--abstraction from ills--preparing for the primal day, our true rest; which, in truth, is the first creation of light, in which all things are viewed and possessed . . . The eighth may possibly turn out to be properly the seventh, and the seventh a day of work. For the creation of the world was concluded in six days . . . The Pythagoreans, as I think, reckon six the perfect number . . . As marriage generates from male and female, so six is generated from the odd number three, which is called the masculine number, and the even number two which is considered feminine. For twice three is six."--Clement, Miscellanies, book 6, chapter 16.
Such is Clement's Scriptureless reasoning on the Sabbath question. And what is his source of authority for the use of "Lord's day" to be applied to the first day of the week? As did several Sunday-keeping "Christian" philosophers of the Alexandrian school, Clement not only spiritualized away Scripture, but he also spiritualized out of Plato's Republic, extracts he could use for "new" Christian teachings! [Plato was an earlier heathen Greek writer who wrote a book called 'The Republic'] Here is the thinking that introduced Sunday as "the Lord's day" into the Christian Church:
"And the Lord's day Plato prophetically speaks of in the tenth book of the Republic, in these words, 'And when seven days have passed to each of them in the meadow, on the eighth day they are to set out and arrive in four days."--Clement, Miscellanies, book 5, chapter 14. [Col 2:6-8,1 Tim 6:20]
Clement says he got the idea from Plato! Because of his very early statements about Sunday-keeping, Clement was considered very important later on to the leaders at Rome, so he was eventually canonized--and declared to be a saint!
So much for Clement--the man who invented the idea that the "Lord's Day" (Revelation 1:10) means Sunday. He was one of several teachers at the Alexandria theology school who wrote--and practiced--praying toward the sun during worship whenever possible. He tells us that he got the idea from the pagan Mithraites. [Ezek 8:16-17].
Offerings for the Dead
About the same time that all these other changes were coming into the church, Tertullian in the third century tells us of some others: "As often as the anniversary [Easter] comes round, we make offerings for the dead as birthday honors." [Ps 106:28.29]. Veneration of the saints and the burning of candles for the dead were not far distant.
The Sign of the Cross
Tertullian, one of the few authenticated Christian writers before 300 A.D., who advocated Sunday-keeping (active 196-220 A.D.), supplies careful instructions for keeping Sunday holy, in place of the Bible Sabbath, and then adds to it another "new idea"--the "sign of the cross":
Offshoot of Worldlings
Jesus warned us against "tradition". [Matt 15:3-9]. Tradition is man-made inventions that have no warrant in Scripture. By the beginning of the third century tradition had reshaped, indeed misshaped, apostolic Christianity. Tradition could produce unity, but not of right doctrine. Christianity, had so conformed to worldly customs that Faustus, a Manichaean living about 400 A.D. [Manichaeans were non-Christians who held certain erroneous beliefs] was able to make against the Christian church a serious charge. Here is what he said:
"You [Christians] appease the shades of the departed with wine and food. You keep the same holidays as the Gentiles . . . In your way of living you have made no change. Plainly you are a mere schism [offshoot of worldlings]; for the only difference from the original is that you meet separately."--Quoted by Augustine, in "Reply to Faustus the Manichaean," book 20, paragraph 4.
Two Contenders
All this time, the influence of Sun worship was rapidly increasing in the Roman Empire. Over the centuries the official religion of the empire had been emperor worship, but it had died out and two strong contenders for popular favor were taking its place. This was Mithra the Sun god, and Christ of Christianity. And, frankly, as the third century neared its close, it was difficult in some of the cities of Egypt and the West to see much difference between the two religions. Fortunately in the rural areas there were the seven thousand who had not bowed the knee to Baal, and who would not do so for several centuries to come, in spite of persecution from their own brethren.
But it would seem that there were those in the church that were doing their best to help the world see that Christ was but another name for Mithra. Cumont tells us that they purposely compared the two as closely as they could so that pagans would be drawn into the church.
The dazzling orb of sunlight, he tells us was exalted as the great symbol of Christ. Christians in certain places had sun-symbols in their churches to help the pagans adjust to the new surroundings. [Deut 4:16-19]. This is where originated the idea of light beams coming from the heads of Christ, and Mary, and the saints.
It had been the custom of the Egyptians and Persians to worship the sun in the morning, and Tacitus (a Roman historian) tells us of this practice in Emperor Vespasian's Roman army in the first century. Tertullian, living west of Alexandria, tells us that he and fellow Christians of his time regularly faced the east when they prayed to Christ their God. He mentions this an essay in which he advocates Sunday-keeping, and rebukes other Christians because they were refraining from work on the Seventh day.
In every case that the present writer can locate, the few men advocating Sunday-keeping prior to 400 A.D.--were the very ones who were introducing pagan heresies to the brethren in the Christian Church. The primary exception were the Roman Bishops, who appeared to be stronger at legislating the heresies upon the churches, than at inventing them.
Along about this time, a youngster was growing up that was destined to powerfully affect the Christian world for all time to come--a boy named Constantine.
Constantine and a State Church (300--350 A.D.)
On the retirement of Emperor Diocletian in 305, it was an uphill fight among several men for the coveted title of Emperor. Fighting continued on and off from 305 till 323. But out of it Constantine emerged as the sole ruler of the vast Roman empire. The crucial battle occurred just north of Rome in October of 312, following which by the Edict of Milan, he gave Christianity full legal equality with every other religion in the empire. More favors to the church soon followed.
Then, on March 7, 321, was issued the first national Sunday Law in history. This was the first "blue law" to be issued by a civil government. Here is the text of Constantine's Sunday Law Decree:
"Let all judges and townspeople and occupations of all trades rest on the Venerable Day of the Sun [Sunday]; nevertheless, let those who are situated in the rural districts freely and with full liberty attend to the cultivation of the fields, because it frequently happens that no other day may be so fitting for ploughing grains or trenching vineyards, lest at the time the advantage of the moment granted by the provision of heaven be lost. Given on the Nones [seventh] of March, Crispus and Constantine being consuls, each of them, for the second. time."--The Code of Justinian, Book Ill, title 12, law 3.
Five additional Sundays Laws were to be issued by Constantine within a very few years to buttress this, his basic one.
When Constantine was issuing his Sunday laws, was he a consistent Christian? Hardly. He was at that very time embellishing The Temple of the Sun in Rome, and in the same year that he proclaimed his first Sunday Law, he made several decrees maintaining pagan practices. The old Roman priests in these superstitious performances decided the most important governmental questions by watching the flight of birds, by examining the entrails of chickens, or by similar superstitions. All this Constantine legalized.
The very next day after giving the Sunday Law of March 7, 321, quoted above, Constantine made another law favoring pagan soothsayers, to the intent that whenever lightning should strike the imperial palace or any other public building, the heathen priests should be consulted as to what it might mean. This they did by looking at the entrails of beasts that had been slaughtered in sacrifice to the gods.
It is to be observed that Constantine's Sunday law was just that--a Sunday law--and nothing more. For Sunday was the great day of the Sun worship cults as well as of compromising Christians. In that law, Christianity is never mentioned. The day is called "the Venerable Day of the Sun" (venarabili die solis). This was the mystical name for the Day of the Sun god. Both the heathen and the Christians well knew this. It is a historical fact that when Constantine issued this first imperial Sunday edict of 321, enforcing the observance of Sunday by the people of the Roman Empire, he was still a worshiper of Sol Invictus--"the Invincible Sun," as well as being the Pontifex Maximus (supreme pagan pontiff or priest) of Roman heathen worship as the state religion.
In another of his six Sunday laws, he gave the order that all of the heathen troops of his army be marched out on the drill field each Sunday in order to recite a prayer composed by the emperor for this purpose. It was worded in such a way that it could be addressed to any god adored by mankind. The soldiers were required by this Sunday law to recite this prayer while facing the sun.
Victor Duruy, a French historian, says this:
"He [Constantine] sent to the legions, to be recited upon that day [Sunday], a form of prayer which could have been employed by a worshiper of Mithra, of Serapis, or of Apollo, quite as well as by a Christian believer. This was the official sanction of the old custom of addressing a prayer to the rising sun."--Victor Duruy, History of Rome, volume 7, page 489.
However, after the death of Licinius (324), his colleague in the imperial office, Constantine openly professed Christianity, though he intentionally postponed baptism until a few days before his death in 337, for he considered baptism as something of a supernatural power to take away sin, and he avoided doing it any sooner than necessary.
Philip Schaff, the noted historian, commenting on the first Sunday Law Decree, clearly shows that the day to be observed was given not under the name Sabbatum [the Sabbath], or dies domini [the Lord's day], but instead, it was given under the heathen title for the day of the sun god dies Solis [the Day of the Sun]. Schaff observes that there was no reference in the law either to Christ, Christianity, or the resurrection of Christ.
But though Constantine meant the law to unite all contending religions into one giant compromising conglomerate, it was thought otherwise by the Christian church leaders of his time. To them it was considered a great victory.
Eusebius and Nicea
Eusebius, bishop of Caesarea (270-338), generally considered to be Constantine's outstanding flatterer in the church, made this remarkable statement:
"All things whatsoever it was duty to do on the [Seventh day] Sabbath, these we [the church] have transferred to the Lord's day."--Commentary on the Psalms, in Migne, Patrologia Graeca, volume 23, column 1171.
Commenting on this heaven-daring statement, one historical writer says this:
"Not a single testimony of the Scriptures was produced in proof of the new doctrine. Eusebius himself unwittingly acknowledges its falsity, and points to the real authors of the change. 'All things,' he says, 'whatever that it was duty to do on the Sabbath, these we have transferred to the Lord's day.' But the Sunday argument, groundless as it was, served to embolden men in trampling upon the Sabbath of the Lord. All who desired to be honored by the world accepted the popular festival."--E.G. White, The Great Controversy, page 574.
This was the beginning of some thing new and ominous within the Christian Church. Rome, itself, the capitol of the mammoth empire, was more licentious, dissipated, and political, than any other city. The influence of it all had reached to the local Christian church there, and a concern to meet the world's standard, as well as a fascination with power-politics had gripped it.
In 325 A.D. the Council of Nicaea met, at which time the church leaders decreed that all honor the resurrection of Christ by keeping the Easter festival--and only on a certain Sunday of each year. Immediately, following this ruling, Constantine issued an imperial order commanding all Christians everywhere to obey the decree of this council. Church and State had united, and whenever in history this has happened persecution of religious dissenters has generally followed. Trouble was ahead for the people of God.
Persecution of God's People Begins (350-- 700 A.D.)
In order to placate church and government authorities, there were those who attempted to keep both days--Sabbath as well as Sunday holy--thus endeavoring to obey God as well as man, for religious persecution against non-observance of Sunday was growing stronger.
For this reason, Sozomen, a church historian of that time, tells us that many "were assembling together on the Sabbath as well as on the first day of the week, which custom is never observed at Rome or at Alexandria."--Sozomen, Ecclesiastical History, book 7, chapter 19, in A Select Library of Nicene and Post -Nicene Fathers, second series, volume 2. [Lk 16:13, Ac 5:39, Gal 1:10].
Even at this late date, Rome and Alexandria continued to be the only bulwarks of Sunday-keeping.
The keeping of both days might seem a practical solution, but it wasn't. The Seventh-day Sabbath was the divinely ordained day for the worship of the Creator. God had never changed it. The Sun day was a man-made institution of worship in honor of a pagan god. To obey both was impossible. [Matt 6:24].
This was exactly the problem the three Hebrew worthies faced at Dura (Read Daniel 5.) They were not at this time forbidden to worship the true God. They need only bow down that day with others in a semblance of worship to the false. But, of course, to do so would signify an acceptance of heathen worship. And this they could not do. They would rather die first. They would rather die than lose something that many in our day consider to be of little value--The Sabbath of the Fourth Commandment given by the God of Heaven Himself.
Now, when in the fourth century it was discovered that some were doing this--keeping both days--this made the religious leaders unhappy--and angry.
They saw that their authority would not be respected as supreme, as long as both days were kept. The Sabbath had to go. And so later in the fourth century, at the Council of Laodicea, for the first time Bible Sabbath-keeping--worshiping on the Seventh day of the week--was forbidden by an official decree of the Christian church. Not to comply meant "anathema"--excommunication. This meant forced separation from church attendance and association with fellow Christians for the rest of their lives unless they recanted and submitted to the authority and teaching of the church. But to submit meant to lose the precious truths of God's Word, and the precious Sabbath.
"Christians shall not Judaize and be idle on Saturday [in the original: Sabbato--shall not be idle on the Sabbath], but shall work on that day; but the Lord's day they shall especially honour, and as being Christians, shall, if possible, do no work on that day. If, however, they are found Judaizing, they shall be shut out [anathema, or excommunicated] from Christ."--Council of Laodicea, Canon 29, in C.J. Hefele, A History of the Councils of the Church, volume 2, page 316.
This talk of "Judaizing" was a cover-up for the real facts in the case. Christians who kept the Seventh-day Sabbath, weren't obeying the Jews--they were obeying God! They weren't Judaizing,--they were Bible-izing!
The first recorded church legislation on this was at Laodicea: "The keeping of the Sunday rest arose from the custom of the people and the constitution of the Church. Tertulian was probably the first to refer to a cessation of affairs on the Sunday; the Council of Laodicea issued the first Council legislation for that day; Constantine 1 issued the first civil legislation." Priest Vincent J. Kelly, Forbidden Sunday and Feast-Day Occupations, page 203. [Roman Catholic] (The exact date of this Council of Laodicea, which marked the first Sunday legislation by the Christian Church, is not known, but is thought to have been in 336 A.D.)
The Council of Laodicea marked the beginning of a new era. When the persecution of God's people began, the extermination of Sabbath-keeping lay at the heart of it.
Something Lost
You see, you're reading the story of people who lost something--something they loved. Rather, it was taken from them--the precious Sabbath they valued, and needed. And they had to stand in silent grief, and watch, as the years passed, and their little children grew up--never having had it.
But there were others who resisted this apostasy against Bible truth. And they paid the highest price for it.
Still others just fled and tried to go into hiding in distant places, taking with them their beloved families and their Bibles, and the truths that meant so much to them.
For us today, there is help only in one line: determine by the grace of God to live right yourself. Study the Bible. And obey it, by the grace of Christ, your Lord and Saviour--at whatever the cost. They were willing to die back then for what the Bible said. Are you willing to suffer today for the same truths? Will you stand for the faith of your fathers?
Plead with your heavenly Father on your knees for a deeper experience. Plead for souls that don't know these precious Bible truths. Live those truths yourself. Your prayers and your daily life--are the best way you can help others live better. And to live better is to live Biblically. Take your stand for God's holy Sabbath, and don't waver, and others will follow your example.
Additional Decrees
Gradually, with the passing of time, additional decrees were passed, restricting what could be done on Sunday, and forbidding religious activities on the Bible Sabbath (governmental decrees in the years 365, 386, 389, 458, 460, 554, 589, 681, 768, 789, and onward, and church council decrees in 343, 538, 578, 581, 690, and onward.) Each law became stricter--every penalty more severe. Satan was determined to destroy the Sabbath, for it represented part of God's will for mankind. In every case, we find human laws suppressing that which God has expressly commanded, the keeping of the seventh-day Sabbath, and in its place exalting a day for which God has made no provision whatever at any time; namely, the day of the sun. Surely here we have a mark, an evidence, of the desire of willful men to set up their own wishes against the wishes of God, and to establish their own traditions in place of the things which God has commanded. "It is the mark of a man." But in spite of all this, the holy Sabbath day of the fourth commandment, although it has for centuries been flouted, still remains the rest day of God, the day of which Christ Himself is Lord and Master.
The Sabbath in 425 A.D.
It is a striking fact that all this time the Seventh-day Sabbath continued to be kept by the majority of Christians in spite of all the inroads of paganism and compromise.
There are those who claim that most Christians had begun to keep the Sunday within two or three hundred years after the time of Christ and the Apostles. This is not true. By the middle of the fourth century under the duress of combined church and state legislation many of the city Christians may have begun compromising in this direction, but the greater majority of the Christians--the Christians outside the cities remained free for a much longer period of time from the encroachment of Sunday pressure.
The important church leader, Augustine, the bishop of the church of Hippo in North Africa, who died in the year 430, acknowledged the widespread keeping of the Sabbath in his day and in a letter to Jerome (the translator of the Roman Catholic Bible), he urged that Christians not be persecuted for keeping it instead of Sunday. In this letter he mentions that the Seventh-day Sabbath was observed in his day "in the greater part of the Christian world." Augustine, himself, was a Sunday-keeper.
Here is what the church historian Socrates, who died about 440 A.D., wrote nearly a hundred years after Constantine's Sunday Law Decree: "Although almost all churches through the world celebrate the sacred mysteries on the Sabbath every week, yet the Christians of Alexandria and at Rome, on account of some ancient tradition, have ceased to do this."--Ecclesiastical History, book 5, chapter 22.
People cannot "cease" to do what they have never done, and so we can know that even at Rome and Alexandria the Bible Sabbath was once kept. But here we see that--amazingly so--400 years after the death of Christ and 100 years after Constantine's linking of church and state by his national Sunday law-Rome and Alexandria were the ONLY places in the world where the majority of Christians kept Sunday and not the Bible Sabbath.
This is truly remarkable. In spite of decrees and punishments; in spite of church leaders and governmental decrees, the true Sabbath of the Bible was being kept everywhere in Christendom a hundred years after Sunday legislation began--except in but two places--Rome and Alexandria. We can understand why Rome had ceased to keep the Sabbath, since for two hundred years it had been emphasizing the keeping of Sunday. We can understand, too, the Alexandrian church's failure to obey God, for that church from its infancy had been the leading influence of Gnostic and speculative philosophy in the church. Throughout the entire history of the changeover from Sabbath to Sunday, Rome and Alexandria had worked together--Alexandria providing philosophical reasons for the changes, Rome providing the decrees and anathema.
Who was the Antichrist?
But all the while there were humble folk who continued to keep the true Sabbath. Humble folk who read their Bible and followed it. But it remained for a pope of Rome to denounce as followers of anti-Christ those who continue to observe the true Sabbath. Gregory 1, named the Great bishop of Rome from A.D. 590 to 604, declared Sabbath-keepers to be preachers of anti-Christ. Here is what he wrote:
"Gregory, bishop by the grace of God to his well-beloved sons, the Roman citizens: It has come to me that certain men of perverse spirit have disseminated among you things depraved and opposed to the holy faith, so that they forbid anything to be done on the day of the Sabbath. What shall I call them except preachers of anti-Christ?"--Epistles, book 13:1, in Labbe and Cossart, Sacrosancta Concilia, volume 5, column 1511.
This shift from Sabbath to Sunday became effective from the fourth through the seventh centuries, at the time when the popes were consolidating their enormous ecclesiastical power.
The Church in the Dark Ages (700-1500 A.D.)
As the centuries rolled by, Sunday observance became increasingly a symbol of the religious power of the Roman Church. Dissenters wherever they might be found were severely punished, but in spite of this, followers of the true Sabbath were to be found in distant or isolated places. For many centuries after Bible Sabbath-keeping had been crushed out of much of the western world, it was still kept in such areas as Britain, Scotland and Ireland. A school was established on the lonely isle of Iona, and from there missionaries went to northern Europe, Switzerland and elsewhere. Eventually the churches in the British Isles were taken over by Rome, but among the Waldenses of the Italian Piedmont and the Swiss Alps, one of the most persecuted and hunted people of the Dark Ages, many kept the Bible Sabbath. Churches that held to this faith also existed for hundreds of years in Central Africa, in Ethiopia and Abyssinia, and among the Armenians and Syrians of Asia. (See Heylyn, History of the Sabbath, part 2, chap. 5, sec. 7; J.H. Merle D'Aubigne, History of the Reformation of the Sixteenth Century, bk. 17, chap. 2; Roger de Hoveden, Annals, vol. 2, pp. 528-530, 281-282; Michael Geddes, Church History of Ethiopia, pp. 311-312, and other books on the Dark Ages.)
The pattern is a simple one: Christian groups that tended to be hidden away in distant places from Rome, and that had access to the Bible in their own language, were the ones who were likely to continue keeping the true Sabbath.
When the northern tribes invaded the empire, the larger number of them accepted the Roman version of Christianity, instead of the purer eastern faith. And so at the request of the pope, they prohibited Sunday work with severe civil decrees in their respective countries.
But the medieval church never mixed Sunday with the Sabbath in their thinking. They recognized and freely admitted that it wasn't the Bible Sabbath. Christians never called Sunday "the sabbath" until modem times.
Interestingly enough, just as is done today, in their blue laws they never forbade amusements on Sunday, except the most objectionable types.
Sunday rest proved difficult to regulate. To church and civil decrees were added superstitious tales of letters from heaven, or miraculous punishments visited upon violators of Sunday.
Gregory, a sixth-century bishop of the city of Tours, in France, wrote up a bookful of them--fire falling from the skies and killing Sabbath-keepers, iron sticking to the hand, blood spurting from the eyes, or thorns growing inside the eyeballs of Sunday violators, and so forth.
In what company has Sunday arisen! Born of tradition, introduced by gnostic philosophers, popularized by Sun worship, clothed in anti-Semitism, enforced by law, sanctified by superstition, finally upheld by the death sentence. All these means have been necessary because of a lack of divine authorization in even one smallest passage of Scripture.
Hidden Churches
But as we have seen, scattered here and there were to be found observers of the true Sabbath--especially in isolated places. Many of the eastern churches, as the centuries passed, continued to hold church services on the Sabbath, and refused to follow the Roman rule of disparaging God's holy day by using it only for a day of fasting and sorrowing, in preparation for Sunday-keeping, as was decreed by Rome.
Many of these hidden churches, such as the Celts of Scotland and the Waldenses of the Alps, were encouraged in their efforts to keep the true Sabbath by the fact that they had the Bible in their own language--a rare thing in those days. It had earlier been discovered that one of the best ways to forbid the Sabbath, was to forbid the Bible along with it.
One of their opponents said this:
"They do not hear the masses of Christians [Catholics] . . . they flee the image of the Crucifix as the devil, they do not celebrate the feasts [holy days] of the divine Virgin Mary and of the Apostles, . . . Some indeed celebrate the Sabbath that the Jews observe!"--Translated by J.J. von Doellinger, Beitraege zur Sek tengeschichte des Mittelalters, volume 2, number 61, page 662.
The Sabbath is a precious gift of God to you. One He wants to share with you. There is a reason why He wants you to keep His Sabbath. And as you yield yourself to His plan you will receive a far greater blessing than you had imagined possible. The Sabbath walk, hand in hand with your God, will extend through the remainder of the week. And a deep peace will come into your life. A happiness known and felt--the quiet rest of soul that comes from obedience to His Word, through faith in Jesus Christ your Lord and Master.
The Bible Sabbath--the Seventh-day Sabbath--is the right Sabbath. It is the only Sabbath God ever gave to you.
May our Heavenly Father bless you, as you return to the faith of your fathers of centuries ago--and the faith of men and women of God in Bible times.
Back to Lesson 22 Additional Information
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Sleep Apnoea, what is it and What you can do about it
Sleep ApnoeaOverview
Sleep apnoea is the condition where breathing temporary stops during sleep. Apnoea is a medical term which means the absence of normal breathing. The condition occurs because of an involuntary relaxation of the muscles of the pharyngeal walls.
People who suffer from sleep apnoea usually snore, snort, or gasp in their sleep. The condition has harmful effects on the quality of sleep and overall health. Because of the repetitive episodes of apnoea, the person would often feel fatigued and tired throughout the day.
Insulin Resistance: The Real Reason Why You Aren’t Losing Weight
Insulin ResistanceInsulin resistance is clinically defined as the inability of the body to utilize insulin. Insulin is a hormone produced by the pancreas which regulates energy utilization. After eating, the pancreas is stimulated to release the hormone insulin. The insulin receptors which are found on every cell should normally respond to the hormone. With insulin resistance, there is unhealthy regulation of glucose, protein, and fat in the body. This condition commonly occurs in people with abdominal obesity, faulty lipid levels, and other factors associated with metabolic syndrome.
Hyperinsulinemia, The Danger of Too Much Insulin
HyperinsulinemiaOvereating and a high carbohydrate diet are risk factors that lead to the development of hyperinsulinemia. Insulin is a hormone that is produced by the pancreas in normal amounts. When people consume too much carbohydrate, the pancreas has to compensate by secreting higher quantities of insulin in order to regulate blood glucose levels.
Insulin is normally used for glucose metabolism. Hyperinsulinemia could also occur when the body cannot effectively use insulin due to resistance. In this case, insulin levels accumulate and pile up all because of resistance.
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Homeworks academic service
A life and work of nicholas copernicus
Nicolaus Copernicus Biography: Facts & Discoveries
Like many students of his time, however, he left before completing his degree, resuming his studies in Italy at the University of Bolognawhere his uncle had obtained a doctorate in canon law in 1473. The Bologna period 1496—1500 was short but significant.
1. Nature quotes the AFP as stating that the reconstruction "bore a striking resemblance to portraits of the young Copernicus.
2. Learn More in these related Britannica articles.
3. Courtesy of the Newberry Library, Chicago A second tradition, deriving from Claudius Ptolemy , solved this problem by postulating three mechanisms.
For a time Copernicus lived in the same house as the principal astronomer at the university, Domenico Maria de Novara Latin: A life and work of nicholas copernicus Maria Novaria Ferrariensis; 1454—1504.
Novara had the responsibility of issuing annual astrological prognostications for the city, forecasts that included all social groups but gave special attention to the fate of the Italian princes and their enemies. Novara also probably introduced Copernicus to two important books that framed his future problematic as a student of the heavens: The first such known observation occurred on March 9, 1497, at Bologna.
By the time he published this observation in 1543, he had made it the basis of a theoretical claim: In 1500 Copernicus spoke before an interested audience in Rome on mathematical subjects, but the exact content of his lectures is unknown. In 1501 he stayed briefly in Frauenburg but soon returned to Italy to continue his studies, this time at the University of Paduawhere he pursued medical studies between 1501 and 1503.
Copernicus later painted a self-portrait; it is likely that he acquired the necessary artistic skills while in Paduasince there was a flourishing community of painters there and in nearby Venice. In May 1503 Copernicus finally received a doctorate—like his uncle, in canon law—but from an Italian university where he had not studied: When he returned to Poland, Bishop Watzenrode arranged a sinecure for him: As a church canon, he collected rents from church-owned lands; secured military defenses; oversaw chapter finances; managed the bakery, brewery, and mills; and cared for the medical needs of the other canons and his uncle.
He used the knowledge of Greek that he had acquired during his A life and work of nicholas copernicus studies to prepare a Latin translation of the aphorisms of an obscure 7th-century Byzantine historian and poet, Theophylactus Simocattes. The work was published in Cracow in 1509 and dedicated to his uncle.
The civil calendar then in use was still the one produced under the reign of Julius Caesarand, over the centuries, it had fallen seriously out of alignment with the actual positions of the Sun.
This rendered the dates of crucial feast days, such as Easterhighly problematic. The leading calendar reformer was Paul of Middelburg, bishop of Fossombrone. At this time the terms astrologer, astronomer, and mathematician were virtually interchangeable; they generally denoted anyone who studied the heavens using mathematical techniques. Pico claimed that astrology ought to be condemned because its practitioners were in disagreement about everything, from the divisions of the zodiac to the minutest observations to the order of the planets.
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From antiquity, astronomical modeling was governed by the premise that the planets move with uniform angular motion on fixed radii at a constant distance from their centres of motion. Two types of models derived from this premise. The first, represented by that of Aristotleheld that the planets are carried around the centre of the universe embedded in unchangeable, material, invisible spheres at fixed distances. Since all planets have the same centre of motion, the universe is made of nested, concentric spheres with no gaps between them.
Aristotle's theory of the solar system.
Nicolaus Copernicus: An Essay On His Life And Work
Courtesy of the Newberry Library, Chicago A second tradition, deriving from Claudius Ptolemysolved this problem by postulating three mechanisms: The equant, however, broke with the main assumption of ancient astronomy because it separated the condition of uniform motion from that of constant distance from the centre.
A planet viewed from the centre c of its orbit would appear to move sometimes faster, sometimes slower. As seen from Earth, removed a distance e from c, the planet would also appear to move nonuniformly. Only from the equant, an imaginary point at distance 2e from Earth, would the planet appear to move uniformly.
1. The Ptolemaic system would have proved sterile because progress would have proven too difficult. Remains thought to be his were discovered in 2005.
2. Copernicus never took orders as a priest, but instead continued to work as a secretary and physician for his uncle in Warmia. Copernicus might have continued this work by considering each planet independently, as did Ptolemy in the Almagest, without any attempt to bring all the models together into a coordinated arrangement.
3. The system is outlined in a short manuscript known as the Commentariolus, or small commentary, which he completed about 1512. At this time the terms astrologer, astronomer, and mathematician were virtually interchangeable; they generally denoted anyone who studied the heavens using mathematical techniques.
A planet-bearing sphere revolving around an equant point will wobble; situate one sphere within another, and the two will collide, disrupting the heavenly order. Ptolemy's theory of the solar system.
See a Problem?
This insight was the starting point for his attempt to resolve the conflict raised by wobbling physical spheres. Copernicus might a life and work of nicholas copernicus continued this work by considering each planet independently, as did Ptolemy in the Almagest, without any attempt to bring all the models together into a coordinated arrangement.
The difficulty focused on the locations of Venus and Mercury. There was general agreement that the Moon and Sun encircled the motionless Earth and that MarsJupiterand Saturn were situated beyond the Sun in that order. In the Commentariolus, Copernicus postulated that, if the Sun is assumed to be at rest and if Earth is assumed to be in motion, then the remaining planets fall into an orderly relationship whereby their sidereal periods increase from the Sun as follows: Mercury 88 daysVenus 225 daysEarth 1 yearMars 1.
It was also necessary to explain how a transient body like Earth, filled with meteorological phenomena, pestilence, and wars, could be part of a perfect and imperishable heaven. In addition, Copernicus was working with many observations that he had inherited from antiquity and whose trustworthiness he could not verify.
Nicolaus Copernicus Biography
It also provided what was missing from the Commentariolus: Both Rheticus and Copernicus knew that they could not definitively rule out all possible alternatives to the heliocentric theory.
Rheticus compared this new universe to a well-tuned musical instrument and to the interlocking wheel-mechanisms of a clock. The theories of his predecessors, he wrote, were like a human figure in which the arms, legs, and head were put together in the form of a disorderly monster.
Nicolaus Copernicus
He chose the top printer in the city, Johann Petreius, who had published a number of ancient and modern astrological works during the 1530s. However, Rheticus was unable to remain and supervise. He turned the manuscript over to Andreas Osiander 1498—1552a theologian experienced in shepherding mathematical books through production as well as a leading political figure in the city and an ardent follower of Luther although he was eventually expelled from the Lutheran church.
In earlier communication with Copernicus, Osiander had urged him to present his ideas as purely hypotheticaland he now introduced certain changes without the permission of either Rheticus or Copernicus. Both Petreius and Rheticus, having trusted Osiander, now found themselves double-crossed. He awoke long enough to realize that he was holding his great book and then expired, publishing as he perished. Learn More in these related Britannica articles:
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Lesson 1: Explanation
An explanation of the preceding conversation
Text in this color indicates literal meanings.
For the sake of comprehension, literal meanings are not always translated word-for-word.
Kul fest, va? Nice party, huh?
means fun. It can also be used to mean nice in this sense.
Va is short for vad (what).
Ja, det är det. Yes, it is. (That it is.).
Vi jobbar tillsammans. We work together.
The verb to work is att jobba.
When there is a subject (I, you, he, she, it, we, they) the verb gets an r:
Jag jobbar (I work or I am working).
This is one of the more common things to neglect, even for advanced learners, so make a special note of it.
Är du också lärare? Are you also a teacher? (Are you also teacher?)
Professions don't get an article (a teacher).
Ja, det är jag. Yes, I am. (Yes, that am I.)
Kommer du från Stockholm? Are you from Stockholm? (Come you from Stockholm?)
Nej, jag är faktiskt inte svensk. No, I'm actually not a Swedish. (I am actually not Swede.)
Like professions, nationalities don't get an article, either.
Är det sant? Really? (Is it true?)
Det är spännande! That's exciting!
Spännande (exciting) is very commonly used, even for things you might find much less than exciting.
Hur länge har du varit i Sverige?
Jag har varit här i nästan tre månader.
How long have you been in Sweden?
I have been here for almost 3 months.
The perfect tenses (have lived, has been, had seen) are very similar to English, though many English speakers learning Swedish note that they are more common in Swedish.
Men du pratar så bra svenska! But you speak such good Swedish!
There are several words for speak or talk in Swedish. Prata is standard and neutral.
Det är en liten stad. It is a small town.
Stad comes from the German word Stadt. It can mean either town or city, but not village. Village is by.
Du då? How about you? (You then?)
Copyright iSpeakSwedish.com 2019
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Markov Models and Hidden Markov Models
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Markov Models and Hidden Markov Models
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Free Resource
In this post will give introduction to Markov models and Hidden Markov models as mathematical abstractions, with some examples.
In probability theory, a Markov model is a stochastic model that assumes the Markov property. A stochastic model models a process where the state depends on previous states in a non-deterministic way. A stochastic process has the Markov property if the conditional probability distribution of future states of the process.
System state is fully observable System state is partially observable
System is autonomous
Markov chain Hidden Markov model
System is controlled
Markov decision process Partially observable Markov decision process
Markov chain
A Markov chain named by Andrey Markov, is a mathematical system that representing transitions from one state to another on a state space. The state is directly visible to the observer. It is a random process usually characterized as memoryless: the next state depends only on the current state and not on the sequence of events that preceded it. This specific kind of "memorylessness" is called the Markov property.
Let's talk about the weather. we have three types of weather sunny, rainy and cloudy.
Let's assume for the moment that the weather lasts all day and it does not change from rainy to sunny in the middle of the day.
Weather prediction is try to guess what the weather will be like tomorrow based on a history of observations of weather
simplified model of weather prediction
Wewill collect statistics on what the weather was like today based on what the weather was like yesterday the day before and so forth. We want to collect the following probabilities.
Using above expression, we can give probabilities of types of weather for tomorrow and the next day using n days of history.
The larger n will be problem in here. The more statistics we must collect Suppose that n=5 then we must collect statistics for 35 = 243 past histories Therefore we will make a simplifying assumption called the "Markov Assumption".
This is called a "first-order Markov assumption" since we say that the probability of an observation at time n only depends on the observation at time n-1. A second-order Markov assumption would have the observation at time n depend on n-1 and n-2. We can the express the joint probability using the “Markov assumption”.
So this now has a profound affect on the number of histories that we have to find statistics for, we now only need 32 = 9 numbers to characterize the probabilities of all of the sequences. (This assumption may or may not be a valid assumption depending on the situation.)
Arbitrarily pick some numbers for P (wtomorrow | wtoday).
Tabel2: Probabilities of Tomorrow's weather based on Today's Weather
“What is w0?” In general, one can think of w as the START word so P(w1w2) is the probability that w1 can start a sentence.
For first-order Markov models we can use these probabilities to draw a probabilistic finite state automaton.
1. Today is sunny what's the probability that tomorrow is sunny and the day after is rainy
First we translates into
• P(w2= sunny,w3=rainy|w1=sunny)
P(w2= sunny,w3=rainy|w1=sunny) = P(w2=sunny|w1=sunny) *
= P(w2=sunny|w1=sunny) * P(w3=rainy|w2=sunny)
= 0.8 * 0.05
Hidden Markov model
A hidden Markov model (HMM) is a statistical Markov model in which the system being modeled is assumed to be a Markov process with unobserved (hidden) states. A HMM can be considered the simplest dynamic Bayesian network. Hidden Markov models are especially known for their application in temporal pattern recognition such as speech, handwriting, gesture recognition, part-of-speech tagging, musical score following, partial discharges and bioinformatics.
Well suppose you were locked in a room for several days and you were asked about the weather outside The only piece of evidence you have is whether the person who comes into the room carrying your daily meal is carrying an umbrella or not.
Table 3: Probabilities of Seeing an Umbrella
The equation for the weather Markov process before you were locked in the room.
Now we have to factor in the fact that the actual weather is hidden from you We do that by using Bayes Rule.
Where ui is true if your caretaker brought an umbrella on day i and false if the caretaker did not. The probability P(w1,..,wn) is the same as the Markov model from the last section and the probability P(u1,..,un) is the prior probability of seeing a particular sequence of umbrella events.
The probability P(w1,..,wn|u1,..,un) can be estimated as,
Assume that for all i given wi, ui is independent of all uj and wj. I and J not equal
Next post will explain about “Markov decision process” and “Partially observable Markov decision process”.
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Opinions expressed by DZone contributors are their own.
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November 1918
A long andvaried history
The Harwich Haven is the only natural deep-water harbour between the Thames and the Humber. Its geography means that great navies have gathered here and people and goods have passed through it for centuries. Surprisingly, though, little is made of the recent military history, not least the momentous events at the end of the First World War when an entire fleet of submarines was brought in and sold off, their crews taken back to Germany without coming ashore. The U-Boats started coming in on the 21st November 1918 and they were anchored off Felixstowe until April 1919.
The armada of over one hundred German U-Boats that ended up in the safe waters of the Harwich Haven had targeted supply lines across the Atlantic in an effort to blockade Britain. Ultimately this policy planted the seeds of German defeat as it provoked the Americans into joining the war. But, initially, unrestricted submarine warfare was a success; in March 1917, for example, twenty-five per cent of all British-bound shipping was sunk and the government was eventually forced to introduce rationing and marshall a Women’s Land Army to help feed a nation with only a few weeks supply of grain left.
German U Boat crew handing over their boat.
A British Navy Minesweeper crew member.
German crew leaving their submarine.
a picture
Specifically, they allow us a unique opportunity to: shift the nation’s focus back from what’s been the well-marked commemoration of events in Europe between 1914 -1918 to the UK; engage with the often forgotten war at sea and how Germany’s submarine blockade created shortages at home; understand how surrender and the Armistice worked on the ground; and explore the consequences of a failed peace settlement for ordinary people in many countries caught up in the escalating refugee crisis of the 1930s as the world marched to war again. Something we explore further in the Sanctuary activities of our project.
Harwich then is the ideal location for a project that not only looks at the surrender of a large, and previously successful, military force but, as importantly, the impact it had on the Home Front, an element of our current
BBC World War One at Home - Harwich, Essex: Over 100 U-boats Surrender
Shortly after the Armistice in November 1918, Harwich was where dozens of German U-boats officially surrendered to the Allied forces. Their exact number is not known, but there were estimated to be between 120 and 150 U-boats in total, along with various other German ships and support machinery.
German U Boat crew handing over their boat.
An arial view of surrender taken from flying boat stationed at Felixstowe.
U Boat avenue across Harwich Haven.
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Vision & Art: Neuroscience 320 at Wellesley College
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Form – Face Perception
All faces are composed of more-or-less the same basic elements (two eyes, a nose, a mouth, eyebrows) set up in roughly the same spatial configuration. Different faces are distinguished by subtle differences in the structure of these elements and their spatial layout. Most people possess an incredible capacity for recognizing a familiar face the instant we lay eyes upon it. Further, we are capable of gleaning important information about the individual’s emotional state, age, sex, and gaze from simply looking at them. Somehow, subtle differences in facial features and their configuration encode all of this information. The exact mechanisms underlying the processes by which our brain extracts this information have not been fully established, although scientists have recently made impressive advances.
Fusiform face area
A cortical brain region containing cells that respond overwhelmingly to faces has been identified—the fusiform face area or FFA. The cells in this region do not respond exclusively to faces, but the exceptions are typically face-like objects, such as a round clock, in which case it is believed that enough of the visual elements match the encoded neural face ‘template’ to activate the face-tuned cells.
Researchers have demonstrated that the spatial relationship of facial features, such as the distance between one’s eyes, is important for face recognition. One useful model for thinking about how these cells might be tuned is this: imagine that two cells exist who care about how far apart a person’s eyes are, and each has a slightly different sensitivity curve to the magnitude of eye displacement—put ‘eye displacement’ along the x-axis and intensity of cell response along the y (measured by firing rate), one cell’s sensitivity curve would peak at the left extreme and the other at the right, and the two would overlap in the middle, which would probably represent the average in the population the individual experienced growing up. Integrating the resulting responses would give the actual distance between a person’s eyes.
It is likely that other higher level features are encoded in this way. Caricatures provide some support for this hypothesis. A caricature is an image in which the facial features of an individual are exaggerated. If the neural basis for evaluating other aspects of facial features is encoded as described above, then extremes should activate the cells better than cases that don’t deviate as far from the norm. And as it turns out, caricatures tend to activate face cells more strongly than photographs.
Nixon Nixon Caricature
Resolution and Recognition
Humans have a remarkable capacity for recognizing faces at low resolutions. Take a look at the image below, can you tell who it is? Back away from your computer and try again. Now mouse over the image to reveal what shouldn’t be a surprise.
Can you guess who this is?
Vision scientists Harmon and Julsez published a block portrait of Abraham Lincoln in the ‘70s demonstrating this phenomenon. Three years later, Salvador Dali produced Gala Contemplating the Mediterranean Sea, which when seen from 20 meters away becomes the portrait of Abraham Lincoln (Homage to Rothko). This 6.3 x 8.3 ft oil on canvas is two paintings in one. At a distance of no more than 20 meters onlookers observe a back-facing nude gazing through a window onto a harbor. Beyond 20 meters, a second image comes into view: a portrait of Abraham Lincoln. Like the Harmon and Julsez block portrait, which is actually inset at the lower left of the painting, the image of Lincoln is composed of colored tiles whose average hue and luminance are analogous to those of the pixels one should find in a low resolution pixilated photograph of Lincoln.
Dali's Gala Contemplating the Mediterranean Sea
Contemporary artist Chuck Close executes a similar feat in his portrait work, but rather than creating one portrait out of another holistic image (like Dail’s Gala), he grids his canvases into tiles; each of the tiles can stand on its own as an abstract composition but when the whole set of tiles is viewed at a distance, a coherent portrait is seen. What Close’s paintings tell us about the psychology of visual perception is useful and surprising: highly detailed features are not necessary to face recognition. Moreover, it is the holistic configuration of features that matters, though researchers are still working to determine which configuration measurements (such as distance between the eyes) are most important and how those spatial relationships are encoded and evaluated. Further, researchers have found that our ability to recognize faces at increasingly low resolution increases with familiarity. Hence, Dali’s choice to depict the iconic image of Abraham Lincoln, one of the most widely familiar faces of his time, contributes to the success of this double-image perceptual-switching painting.
Facial Expressions
Facial expressions are a form of nonverbal communication governed by the contraction and relaxation of facial muscles. They convey information regarding the individual’s emotional status, though voluntary action can be used to override the involuntary expression in some cases. Darwin showed that facial expressions were universal across cultures, and even drew parallels with other species.
Facial expressions are most apparent at lower-resolution, probably due to blurring caused by subcutaneous fat above the muscles, as suggested by Maragaret Livingstone in her book Vision and Art: The Biology of Seeing. In the text, she points out that this can be observed in Leonardo DaVinci’s Mona Lisa where viewing Lisa’s mouth from your periphery draws out her illusory smile. It was also found that low resolution images of a woman baring a frightened face generated stronger responses in the amygdala, the brain region responsible for vigilance response, of subjects than did the fine details.
Created by : Kate Ciurej ‘08 and Donna Yee ’11
Created: July 9, 2008
Maintained By: Bevil Conway
Last Modified:July 21, 2013
Expires: July 21, 2013
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Prokaryotic Diversity
Learning Objectives
• Describe the evolutionary history of prokaryotes
• Discuss the distinguishing features of extremophiles
• Explain why it is difficult to culture prokaryotes
Prokaryotes, the First Inhabitants of Earth
When and where did life begin? What were the conditions on Earth when life began? Prokaryotes were the first forms of life on Earth, and they existed for billions of years before plants and animals appeared. The Earth and its moon are thought to be about 4.54 billion years old. This estimate is based on evidence from radiometric dating of meteorite material together with other substrate material from Earth and the moon. Early Earth had a very different atmosphere (contained less molecular oxygen) than it does today and was subjected to strong radiation; thus, the first organisms would have flourished where they were more protected, such as in ocean depths or beneath the surface of the Earth. At this time too, strong volcanic activity was common on Earth, so it is likely that these first organisms—the first prokaryotes—were adapted to very high temperatures. Early Earth was prone to geological upheaval and volcanic eruption, and was subject to bombardment by mutagenic radiation from the sun. The first organisms were prokaryotes that could withstand these harsh conditions.
Microbial Mats
Microbial mats or large biofilms may represent the earliest forms of life on Earth; there is fossil evidence of their presence starting about 3.5 billion years ago. A microbial mat is a multi-layered sheet of prokaryotes (Figure 1) that includes mostly bacteria, but also archaea. Microbial mats are a few centimeters thick, and they typically grow where different types of materials interface, mostly on moist surfaces. The various types of prokaryotes that comprise them carry out different metabolic pathways, and that is the reason for their various colors. Prokaryotes in a microbial mat are held together by a glue-like sticky substance that they secrete called extracellular matrix.
The part a photo shows a reddish-yellow mound with small chimneys growing out of it. Part b micrograph shows rod-shaped bacteria about two microns long swimming over a thicker mat of bacteria.
Fossilized microbial mats represent the earliest record of life on Earth. A stromatolite is a sedimentary structure formed when minerals are precipitated out of water by prokaryotes in a microbial mat (Figure 2). Stromatolites form layered rocks made of carbonate or silicate. Although most stromatolites are artifacts from the past, there are places on Earth where stromatolites are still forming. For example, growing stromatolites have been found in the Anza-Borrego Desert State Park in San Diego County, California.
Photo A shows a mass of gray mounds in shallow water. Photo B shows a swirl patter in white and gray marbled rock.
The Ancient Atmosphere
This photo shows a woman squatting next to a stream of green-colored water.
Figure 3. This hot spring in Yellowstone National Park flows toward the foreground. Cyanobacteria in the spring are green, and as water flows down the gradient, the intensity of the color increases as cell density increases. The water is cooler at the edges of the stream than in the center, causing the edges to appear greener. (credit: Graciela Brelles-Mariño)
Microbes Are Adaptable: Life in Moderate and Extreme Environments
Some organisms have developed strategies that allow them to survive harsh conditions. Prokaryotes thrive in a vast array of environments: Some grow in conditions that would seem very normal to us, whereas others are able to thrive and grow under conditions that would kill a plant or animal. Almost all prokaryotes have a cell wall, a protective structure that allows them to survive in both hyper- and hypo-osmotic conditions. Some soil bacteria are able to form endospores that resist heat and drought, thereby allowing the organism to survive until favorable conditions recur. These adaptations, along with others, allow bacteria to be the most abundant life form in all terrestrial and aquatic ecosystems.
This micrograph shows an oval Deinococcus about 2.5 microns in diameter cell dividing.
Figure 4. Deinococcus radiodurans, visualized in this false color transmission electron micrograph, is a prokaryote that can tolerate very high doses of ionizing radiation. It has developed DNA repair mechanisms that allow it to reconstruct its chromosome even if it has been broken into hundreds of pieces by radiation or heat. (credit: modification of work by Michael Daly; scale-bar data from Matt Russell)
Other bacteria and archaea are adapted to grow under extreme conditions and are called extremophiles, meaning “lovers of extremes.” Extremophiles have been found in all kinds of environments: the depth of the oceans, hot springs, the Artic and the Antarctic, in very dry places, deep inside Earth, in harsh chemical environments, and in high radiation environments (Figure 4), just to mention a few. These organisms give us a better understanding of prokaryotic diversity and open up the possibility of finding new prokaryotic species that may lead to the discovery of new therapeutic drugs or have industrial applications. Because they have specialized adaptations that allow them to live in extreme conditions, many extremophiles cannot survive in moderate environments. There are many different groups of extremophiles: They are identified based on the conditions in which they grow best, and several habitats are extreme in multiple ways. For example, a soda lake is both salty and alkaline, so organisms that live in a soda lake must be both alkaliphiles and halophiles (Table 1). Other extremophiles, like radioresistant organisms, do not prefer an extreme environment (in this case, one with high levels of radiation), but have adapted to survive in it (Figure 4).
Table 1. Extremophiles and Their Preferred Conditions
Extremophile Type Conditions for Optimal Growth
Acidophiles pH 3 or below
Alkaliphiles pH 9 or above
Psychrophiles Temperature of -15-10 °C (5-50 °F) or lower
Halophiles Salt concentration of at least 0.2 M
Osmophiles High sugar concentration
Prokaryotes in the Dead Sea
One example of a very harsh environment is the Dead Sea, a hypersaline basin that is located between Jordan and Israel. Hypersaline environments are essentially concentrated seawater. In the Dead Sea, the sodium concentration is 10 times higher than that of seawater, and the water contains high levels of magnesium (about 40 times higher than in seawater) that would be toxic to most living things. Iron, calcium, and magnesium, elements that form divalent ions (Fe2+, Ca2+, and Mg2+), produce what is commonly referred to as “hard” water. Taken together, the high concentration of divalent cations, the acidic pH (6.0), and the intense solar radiation flux make the Dead Sea a unique, and uniquely hostile, ecosystem (Figure 5).
Photo A shows the Dead Sea and its accompanying brown shoreline. Micrograph B shows rod-shaped halobacteria.
Figure 5. (a) The Dead Sea is hypersaline. Nevertheless, salt-tolerant bacteria thrive in this sea. (b) These halobacteria cells can form salt-tolerant bacterial mats. (credit a: Julien Menichini; credit b: NASA; scale-bar data from Matt Russell)
What sort of prokaryotes do we find in the Dead Sea? The extremely salt-tolerant bacterial mats include Halobacterium, Haloferax volcanii (which is found in other locations, not only the Dead Sea), Halorubrum sodomense, and Halobaculum gomorrense, and the archaea Haloarcula marismortui, among others.
Unculturable Prokaryotes and the Viable-but-Non-Culturable State
Two bacterial plates with red agar are shown. Both plates are covered with bacterial colonies. On the right plate, which contains hemolytic bacteria, the red agar has turned clear where bacteria are growing. On the left plate, which contains non-hemolytic bacteria, the agar is not clear.
Figure 6. In these agar plates, the growth medium is supplemented with red blood cells. Blood agar becomes transparent in the presence of hemolytic Streptococcus, which destroys red blood cells and is used to diagnose Streptococcus infections. The plate on the left is inoculated with non-hemolytic Staphylococcus (large white colonies), and the plate on the right is inoculated with hemolytic Streptococcus (tiny clear colonies). If you look closely at the right plate, you can see that the agar surrounding the bacteria has turned clear. (credit: Bill Branson, NCI)
Microbiologists typically grow prokaryotes in the laboratory using an appropriate culture medium containing all the nutrients needed by the target organism. The medium can be liquid, broth, or solid. After an incubation time at the right temperature, there should be evidence of microbial growth (Figure 6). The process of culturing bacteria is complex and is one of the greatest discoveries of modern science. German physician Robert Koch is credited with discovering the techniques for pure culture, including staining and using growth media. His assistant Julius Petri invented the Petri dish whose use persists in today’s laboratories. Koch worked primarily with the Mycobacterium tuberculosis bacterium that causes tuberculosis and developed postulates to identify disease-causing organisms that continue to be widely used in the medical community. Koch’s postulates include that an organism can be identified as the cause of disease when it is present in all infected samples and absent in all healthy samples, and it is able to reproduce the infection after being cultured multiple times. Today, cultures remain a primary diagnostic tool in medicine and other areas of molecular biology.
Some prokaryotes, however, cannot grow in a laboratory setting. In fact, over 99 percent of bacteria and archaea are unculturable. For the most part, this is due to a lack of knowledge as to what to feed these organisms and how to grow them; they have special requirements for growth that remain unknown to scientists, such as needing specific micronutrients, pH, temperature, pressure, co-factors, or co-metabolites. Some bacteria cannot be cultured because they are obligate intracellular parasites and cannot be grown outside a host cell.
In other cases, culturable organisms become unculturable under stressful conditions, even though the same organism could be cultured previously. Those organisms that cannot be cultured but are not dead are in a viable-but-non-culturable (VBNC) state. The VBNC state occurs when prokaryotes respond to environmental stressors by entering a dormant state that allows their survival. The criteria for entering into the VBNC state are not completely understood. In a process called resuscitation, the prokaryote can go back to “normal” life when environmental conditions improve.
Is the VBNC state an unusual way of living for prokaryotes? In fact, most of the prokaryotes living in the soil or in oceanic waters are non-culturable. It has been said that only a small fraction, perhaps one percent, of prokaryotes can be cultured under laboratory conditions. If these organisms are non-culturable, then how is it known whether they are present and alive? Microbiologists use molecular techniques, such as the polymerase chain reaction (PCR), to amplify selected portions of DNA of prokaryotes, demonstrating their existence. Recall that PCR can make billions of copies of a DNA segment in a process called amplification.
The Ecology of Biofilms
Until a couple of decades ago, microbiologists used to think of prokaryotes as isolated entities living apart. This model, however, does not reflect the true ecology of prokaryotes, most of which prefer to live in communities where they can interact. A biofilm is a microbial community (Figure 7) held together in a gummy-textured matrix that consists primarily of polysaccharides secreted by the organisms, together with some proteins and nucleic acids. Biofilms grow attached to surfaces. Some of the best-studied biofilms are composed of prokaryotes, although fungal biofilms have also been described as well as some composed of a mixture of fungi and bacteria.
Biofilms are present almost everywhere: they can cause the clogging of pipes and readily colonize surfaces in industrial settings. In recent, large-scale outbreaks of bacterial contamination of food, biofilms have played a major role. They also colonize household surfaces, such as kitchen counters, cutting boards, sinks, and toilets, as well as places on the human body, such as the surfaces of our teeth.
Art Connection
Compared to free-floating bacteria, bacteria in biofilms often show increased resistance to antibiotics and detergents. Why do you think this might be the case?
The extracellular matrix and outer layer of cells protects the inner bacteria. The close proximity of cells also facilitates lateral gene transfer, a process by which genes such as antibiotic resistance genes are transferred from one bacterium to another. And even if lateral gene transfer does not occur, one bacterium that produces an exo-enzyme that destroys antibiotic may save neighboring bacteria.
Section Summary
Prokaryotes existed for billions of years before plants and animals appeared. Hot springs and hydrothermal vents may have been the environments in which life began. Microbial mats are thought to represent the earliest forms of life on Earth, and there is fossil evidence of their presence about 3.5 billion years ago. A microbial mat is a multi-layered sheet of prokaryotes that grows at interfaces between different types of material, mostly on moist surfaces. During the first 2 billion years, the atmosphere was anoxic and only anaerobic organisms were able to live. Cyanobacteria evolved from early phototrophs and began the oxygenation of the atmosphere. The increase in oxygen concentration allowed the evolution of other life forms. Fossilized microbial mats are called stromatolites and consist of laminated organo-sedimentary structures formed by precipitation of minerals by prokaryotes. They represent the earliest fossil record of life on Earth.
Bacteria and archaea grow in virtually every environment. Those that survive under extreme conditions are called extremophiles (extreme lovers). Some prokaryotes cannot grow in a laboratory setting, but they are not dead. They are in the viable-but-non-culturable (VBNC) state. The VBNC state occurs when prokaryotes enter a dormant state in response to environmental stressors. Most prokaryotes are social and prefer to live in communities where interactions take place. A biofilm is a microbial community held together in a gummy-textured matrix.
acidophile: organism with optimal growth pH of three or below
alkaliphile: organism with optimal growth pH of nine or above
anaerobic: refers to organisms that grow without oxygen
anoxic: without oxygen
biofilm: microbial community that is held together by a gummy-textured matrix
cyanobacteria: bacteria that evolved from early phototrophs and oxygenated the atmosphere; also known as blue-green algae
extremophile: organism that grows under extreme or harsh conditions
halophile: organism that require a salt concentration of at least 0.2 M
hydrothermal vent: fissure in Earth’s surface that releases geothermally heated water
hyperthermophile: organism that grows at temperatures between 80–122 °C
microbial mat: multi-layered sheet of prokaryotes that may include bacteria and archaea
nutrient: essential substances for growth, such as carbon and nitrogen
osmophile: organism that grows in a high sugar concentration
phototroph: organism that is able to make its own food by converting solar energy to chemical energy
psychrophile: organism that grows at temperatures of -15 °C or lower
radioresistant: organism that grows in high levels of radiation
resuscitation: process by which prokaryotes that are in the VBNC state return to viability
stromatolite: layered sedimentary structure formed by precipitation of minerals by prokaryotes in microbial mats
thermophile: organism that lives at temperatures between 60–80 °C
viable-but-non-culturable (VBNC) state: survival mechanism of bacteria facing environmental stress conditions
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TOEFL Writing Essential Words - Part 6 - dominate and predominate
Madison Oster May 31st, 2018
Today’s post is an advanced lesson for a lot of TOEFL and IELTS test takers. During your TOEFL and IELTS preparations, you probably came across the following words: dominate, dominant, dominance, domination, predominate, predominant, predominance, and predominantly.
A lot of students look up these words in the dictionary but still don’t truly understand them. So in today’s post, we are going to look at each of these words and give you various examples to demonstrate how to use them. This way you will understand the difference between them and will be able to use them correctly.
So let’s get started!
Dominate VS Predominate
The first words we are looking at are "dominate" and "predominate".
Difference #1
While both of them can be used interchangeably in some sentences, normally "dominate" is used to mean “to have or exert power or influence over something/somebody” "Predominate" on the other hand is mostly used as “to be the most common”. However, dominate can mean “to be the most common”, as well, and this is where it gets confusing. But more on this later. Lets talk about dominate in the sense of “to rule or control something.” first.
Dominate is almost always used with an object. We often see it used in business and sports. Let’s have a look at some examples:
• The Chicago bulls dominated the NBA in 1996.
• Our company dominates the market for operating systems.
• Google and Facebook dominate the fast-growing market for online advertising.
You may encounter the word "dominate" in your history or politics class, as well. Like in the following textbook sample:
• The Han Dynasty of China has dominated much of ancient East Asia for a long time.
As said before, "dominate" can also mean ‘to be the most common”. This usage appears quite often in TOEFL academic lectures or passages. So, let’s look at some TOEFL academic style example sentences:
• Invertebrates dominate deep sea regions = Invertebrates are the most common species in deep-sea regions.
• Mars' atmosphere is dominated by carbon dioxide. = Carbon dioxide is the most abundant gas in Mars' atmosphere.
Since we are using dominate with the meaning “to be the most common”, predominate, in this instance, is a synonym, so let's have a look now. I could say “Invertebrates predominate in deep-sea regions.” instead of “invertebrates dominate deep-sea regions.” I will explain why "in” is necessary for that sentence to make sense.
Remember we cannot always replace dominate with predominate. Take this sentence here for example:
• Our company dominates the market for operating systems.
• Here dominate means have power and influence over the market.
If we use the verb predominate, the sentence becomes
• Our company predominates in the market for operating systems. (awkward!)
That’s not completely wrong, but native speakers wouldn’t normally write or say it like that. This is because “predominate” is not often used in the sense of “controling or ruling something” while "dominate" is.
Let me give you a better example using predominate:
• It appears that oak trees predominate in this forest. (Here it means oak trees are the most common trees in this forest)
Difference #2
You're going to learn why "in" was used, so pay attention :)
There is another difference between dominate and predominate. The verb “predominate” is an intransitive verb, meaning it doesn’t take an object, whereas dominate is a transitive verb, meaning it does take objects. That is why we used “in” with predominate before.
Let’s look at the following example sentence using “dominate”
• Carbon dioxide dominates Mars’ atmosphere.
As you can see, the verb “dominates” takes the object, which is “Mars’ atmosphere”.
We can change this sentence using predominate because dominate here means being the most common. But we cannot simply exchange the two words. We have to write it like this:
• Carbon dioxide predominates in Mars' atmosphere.
So we have to use the preposition “in” here, since “predominate” doesn’t take a direct object.
Let’s look at more example sentences of the verb “predominate” where the same applies: :
• Cottages predominate along the beach. (This means most of the buildings along the beach are cottages)
• Rain predominates in the tropical regions. (This means that there is a great deal of rain in the tropical regions)
• Older people predominate in this neighborhood.
The word predominate is sometimes used with the preposition “over”. So when “A predominates over B” means “A is more common than B”. Let’s look at the following examples:
• In the surface soil, oxygen generally predominates over carbon dioxide.
• In this area immigrants predominate over local people.
• Pine trees predominate over oak trees in this park.
You should make sure that you understand the difference between “dominate” and "predominate" as this is crucial to understand the differences between the following words: "dominance" and "predominance", and "dominant" and "predominant" later.
To help you, we have summarized the differences for you here. As a rule of thumb, you should use 'dominate" when you want to express the meaning of “control or power” and when you have an object. You should use predominate when you refer to something being the most common or is widespread in a certain area. Use dominate when you speak about the influence of something. and predominate when you talk about numbers.
Dominance VS Predominance
Let’s look at the nouns. “dominance” and “predominance”.
Similar to the verbs, the noun “dominance”means power and influence over others. And “predominance” means the state or condition of being most common. Let’s look at an example:
• The ongoing and increasing dominance of English in world culture and commerce will continue to provide many advantages to Britain in many areas.
Here we imply “There is a greater influence of English over other languages in world culture”
If we replace “dominance” with “predominance” like the following sentence
• The ongoing and increasing predominance of English in world culture and commerce will continue to provide many advantages to Britain in many areas.
We imply “There is a greater commonness of English over other languages in world culture”
So we can change dominance to predominance in this sentence but it changes the meaning slightly from “English being influential” to “English being widespread”.
Let’s look at another example using "predominance"
• There is a predominance of older people in the neighborhood. (This means there is a greater number of older people in the neighborhood)
Please note that the noun “dominance” isn’t really used for the state or condition of being the most common. So, the following sentence is incorrect
• There is a dominance of older people in the neighborhood. (incorrect)
However, since the verb “dominate” can be used in the sense of “to be common”, you could use the verb ”dominate” here,
• Older people dominate this neighborhood.
Here are more examples using “predominance”:
• Despite the predominance of female teachers in school, administrative positions are held mostly by men. = Despite most of the teachers in school being women, administrative positions are held mostly by men.
• The predominance of individualist feminism in English-speaking countries is a historical phenomenon.
• There is an overwhelming predominance of female images in prehistoric art.
As we know, “dominance” means the power and influence over others, so the phrase “gain dominance” is often used. For example:
• Hollywood continues to gain dominance in the international film market. = Hollywood’s dominance in the international film market continuously increases.
Dominant VS Predominant
So far we have looked at “dominate”, “predominate”, “dominance”, and ‘predominance“. Let’s look at “dominant” and “predominant”.
Both adjectives are often used interchangeably, but at the same time, there are occasions where you can use only one of them. Take these two sentences for example.
• Newspapers play a dominant role in shaping public opinion.
• Newspapers play a predominant role in shaping public opinion.
Both sentences are correct, but the first sentence is recommended. Why you ask? You can stick to our rule of thumb here: We want to talk about the influence Newspapers have, so we should use dominant. Here the meaning of dominant is “influential”. But be prepared to see both versions.
When we want to refer to the meaning of “being common”, dominant and predominant are both often used. But even then, using predominant is recommended. The following sentence helps to demonstrate this:
• The most predominant color in this room is beige.
So using our rule of thumb here, we should use "predominant". What we want to say is that beige is the color mostly used in the room. However, here many people use dominant as well, especially when we mean that the beige color gives the room an overall atmosphere.
So you could also say “the dominant color in this room is beige”.
While we use dominant and predominant often interchangeably, there are examples where predominant does not work. One example comes from genetics, In genetics there are so-called dominant genes. These are genes which define heritable characteristics even if only one parent carries the genes for those characteristics. Among others, dominant can be used for dominant genes, dominant traits, dominant characteristics or even dominant behavior. For example:
• (Correct!) Brown hair is a dominant trait. (This means brown hair is dominant)
• (Incorrect!) Brown hair is a predominant trait.
Let's look at more examples using the word "dominant".
• The university plays a dominant role in the local economy.
• Money is the dominant force in consumer societies.
And here are more examples using the word "predominant".
• Red is the predominant color in the painting.
• Religion is the predominant theme of the play. (This means in the play they are displaying many things that are related to religion).
The final word we'll discuss in this article is “Domination”.
The noun “domination” is different from “dominance”. Dominance means “the condition of being dominant”, which basically means “have power or influence over others”, while the noun domination is the "act of dominating somebody or something. It can also refer to the condition of being dominated.”
Did you notice the difference? Let’s look at some examples using domination.
• It wasn’t until the First World War that the U.S began to seriously challenge the British domination of South Africa.
• European domination of India led to a rise in Indian nationalism.
So why do we use domination here? Because here we want to emphasize the act of dominating something. For instance in “European domination of India” we are implying that Europe actually exerts its power over India by military and economic means.
The terms “political domination”,“market domination”, “economic domination” and “military domination” are often used. Here are example sentences:
The most effective method for market domination is to create a niche market.
• You're more likely to succeed at market domination if your business faces little or no competition.
• Political domination is a crucial aspect of colonialism.
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advantages shear wall
advantages shear wall
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Shear wall construction Britannica.com
Shear wall, In building construction, a rigid vertical diaphragm capable of transferring lateral forces from exterior walls, floors, and roofs to the ground foundation in a direction parallel to their planes. Examples are the reinforced-concrete wall or vertical truss. Lateral forces caused by wind, earthquake, and uneven settlement 【Get Price】
SHEAR WALL - Free Engineering Seminars
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Facts About Fire You Must Know
It’s normal for anyone to be hesitant or sceptical towards undertaking an exercise he or she has little knowledge about. Our attitudes in such situations are quite pronounced due to fear of the unknown. But when you have been informed or trained adequately about the activity you have to undertake, you approach it with a lot of confidence. Imagine how you feel when all of a sudden fire started in your room. In the first instance, you’re most likely to panic. That is why it is very important to know how fires start in the first place. This is what we want to discuss today.
Fire can be started by the presence of three (3) main things:
• Fuel – any solid (e.g. paper, pieces of wood, plastics, rubber, etc), liquid (e.g. cooking oil, petrol, diesel, kerosene, etc), gas (e.g. LPG, etc) or anything that contains carbonaceous substance.
• Oxygen – ever presence in the atmosphere.
• Heat – this comes from heat energy sources such as mechanical, chemical, nuclear, solar and electrical, hot works such as welding, cutting can result in sparks.
Some people refer to these three elements as Fire Triangle. When these three elements come together, it leads to a process we call burning or combustion. But when one of these elements is not present, fire or burning cannot take place. There’s no way a fire would start with presence of any two of the elements. That’s why when fire starts in a room, it is advisable to quickly shut doors and windows immediately provided it is safe to do so. It is done to prevent more air coming into the room to increase the burning process. What’s most fundamental, however, is that oxygen is ever presence in the atmosphere and fuel plays a very key role in the start of a fire.
It is therefore not advisable to store books, cardboards, etc near switches and plugs because they generate sparks when they are switched on and off but the sparks are not visible enough unless it is done in total darkness.
Photo credit: common.wikimedia.org
Having established all of the above, let’s now turn our attention to some other important aspect about fire. There are mainly six (6) classes of fire and it’s often determined by the type of fuel involved:
Class A – This is made up of organic solids that have carbonaceous substances such as paper, coal, textile, fibre, wood and plastic. For example, if you lit a match and place it on a piece of textile in the presence of oxygen, there will be combustion leading to fire.
Class B – It’s made up of liquids that are flammable for example oil, solvents, paraffin, diesel, petrol, kerosene, alcohol, spirit, turpentine, oil paint, grease, butter, shea butter. For example, when you drop butter (fuel) on a hot surface that has generated heat with the presence of oxygen, combustion will take place and thereby leads to fire.
Class C – It’s made up of flammable gases such as methane, acetylene, propane, butane. For instance, if you use LPG to cook in your home, there’s always the presence of oxygen without which you would not be able to light the stove. Also, when you drop live cigarette butt in a place where any of the gases mentioned above is present, there’s no doubt the place will explode.
Class D – This is a fire involving metals such as aluminium, magnesium, titanium, iron, steel. When welders are grinding metals, you would find that a lot of sparks are generated. There is always the presence of oxygen and so if the sparks fall on another combustible material for example a piece of wood, it can result in combustion leading to fire. Again, when live electrical naked wires, for example, come into contact with each other, the friction generates sparks which create fire.
Class E – Fires involving electrical apparatus. For example, when you plug a water heater and left it unattended, it will explode after all the water has dried up. Defective electrical appliances can also cause fire.
Class F – High temperature fats and oils such as cooking fat. Since these are high temperature fats, if they’re not properly stored, it can create fire. For example, storing them close to a source of heat can cause fire.
• Three things start fire:
• fuel,
• oxygen and
• heat.
To stop or prevent fire, remove one of the elements by simply avoiding bringing these three elements together.
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[ "article:topic" ]
Humanities Libertexts
3.6: Comparison and Contrast
• Page ID
• The Purpose of Comparison and Contrast in Writing
Comparison in writing discusses elements that are similar, while contrast in writing discusses elements that are different. A compare-and-contrast essay, then, analyzes two subjects by examining them closely and comparing them, contrasting them, or both.
Exercise 16
• Romantic comedies
• Internet search engines
• Cell phones
Exercise 17
• Department stores and discount retail stores
• Fast food chains and fine dining restaurants
• Dogs and cats
The Structure of a Comparison-and-Contrast Essay
1. According to the subjects themselves, discussing one and then the other
See the "Comparison and Contrast Diagram," which diagrams ways to organize our organic versus conventional vegetables thesis. The organizational structure you choose depends on the nature of the topic, your purpose, and your audience.
Given that compare-and-contrast essays analyze the relationship between two subjects, it is helpful to have some phrases on hand that will cue the reader to such analysis. See Table of "Phrases of Comparison and Contrast" for examples.
Table of Phrases of Comparison and Contrast
Comparison Contrast
one similarity one difference
Both conversely
Like in contrast
Likewise unlike
Similarly while
in a similar fashion whereas
Figure \(\PageIndex{1}\) - Comparison and Contrast Diagram
Exercise 18
Create an outline for each of the items you chose in Exercise 16 and Exercise 17 Use the pointby-point organizing strategy for one of them, and use the subject organizing strategy for the other.
Writing a Comparison-and-Contrast Essay
First choose whether you want to compare seemingly disparate subjects, contrast seemingly similar subjects, or compare and contrast subjects. Once you have decided on a topic, introduce it with an engaging opening paragraph. Your thesis should come at the end of the introduction, and it should establish the subjects you will compare, contrast, or both, as well as state what can be learned from doing so. Be sure to make an argument in your thesis; explain to the reader what’s at stake in analyzing the relationship between your stated subjects.
After you finish analyzing the subjects, write a conclusion that summarizes the main points of the essay and reinforces your thesis. See the student essay that follows, “Batman: A Hero for Any Time,” as well as the professional essays at the end of this chapter to read some examples of the compare-and-contrast essay.
Exercise 19
Choose one of the outlines you created in Exercise 18 and write a full compare-and-contrast essay. Be sure to include an engaging introduction, a clear thesis, well-defined and detailed paragraphs, and a fitting conclusion that ties everything together.
Sample Comparison-and-Contrast Essay
In “Batman: A Hero for Any Time,” Jacob Gallman-Dreiling compares the traditional portrayal of the superhero Batman with the modern version. As you read, look for the comparison and contrast phrases that the author uses to help the reader understand the argument he is making. What kind of organizational structure does the essay follow?
Jacob Gallman-Dreiling
English 1101
Dr. Cox
16 March 2013
Thesis: Although the framework of the Batman story always remains the same, the character has been re-imagined over time to suit the changing expectations of a hero through his characterization as well as that of those who surround him, both friends and foes.
1. The backstory for Batman has always remained the same.
1. Bruce Wayne is the son of wealthy socialites.
1. Bruce Wayne’s parents are murdered in front of him.
2. Bruce Wayne grows up to inherit his parents’ fortune.
2. Bruce Wayne becomes Batman to avenge the violence of his parents’ death.
1. Batman fights crime with the help of Commissioner Gordon and others.
2. Batman employs an arsenal of non-lethal weapons to aid him.
2. The characterization of Batman has changed to fit the changing expectations of a hero.
1. In the Silver Age of comic books, Batman was portrayed as a sunny, pulpy character.
1. Batman’s stories had to adhere to the guidelines of the Comics Code Authority.
1. Characters could not use concealed weapons.
2. Stories required “morals.”
3. Stories could not use kidnapping or excessive violence.
4. Stories incorporated elements of science fiction.
5. Stories had limitations on the portrayal of female characters.
2. Batman’s suits often had ridiculous properties he conveniently prepared for the upcoming mission.
2. In modern portrayals, Batman is a tortured and flawed character.
1. Batman is haunted by the death of his parents.
2. Batman has become a skilled detective and fighter.
3. Batman’s suit is more armor than spandex.
4. Batman is haunted by his mistakes.
5. Batman and Commissioner Gordon conspire to hide the truth about Harvey Dent from the people of Gotham.
3. The characterization of Batman’s associates has changed to fit the changing expectations of a hero.
1. In the Silver Age of comic books, Batman’s associates were correspondingly lighthearted.
1. Characters like Ace the Bat-Hound, Bat-Mice, and Batwoman were created to draw in children.
2. Issues were built around a villain-of-the-week.
2. In modern portrayals, Batman’s associates deal with real consequences and changes.
1. Dick Grayson grows up and goes to college.
2. Batgirl is paralyzed by the Joker.
3. Joker is given several conflicting backstories explaining his psychosis.
4. Catwoman has changed from a harmless cat-burglar to a reformed prostitute.
Student Essay
Jacob Gallman-Dreiling
English 1101
Dr. Cox
16 March 2013
Batman: A Hero for Any Time
Few ideas in this world are as timeless as that of a superhero. The ancient Greeks had Odysseus and Hercules. The British have Sherlock Holmes and Allan Quatermain. The Americans developed the modern concept of the superhero with characters like Superman and Spider-Man and created elaborate stories for the origin of their powers, much like the Greeks used when creating their heroes. While the world of superheroes was originally a white man’s club, the creation of Wonder Woman ushered in a new era of diversity. Now men, women, people of color, even those of differing sexual orientations are represented among the ranks of those who fight against evil. Though teams of superheroes like the Justice League of America and the XMen have enduring popularity, few superheroes have captured the imagination like Batman. Created in 1939 by Bob Kane and Bill Finger, a boy orphaned by violence grows to become the Caped Crusader, avenger of the fictional of Gotham. This comic book hero has spurred film, radio, and television adaptations, has spawned action figures and video games, and has maintained an uninterrupted comic book publication, something few other superhero titles can boast. Although the framework of the Batman story always remains the same, the character has been re-imagined over time to suit the changing expectations of a hero through his characterization as well as through the portrayal of those who surround him, both friends and foes.
The basic framework of the Batman story has stayed the same since his debut in May, 1939. At the age of eight, Bruce Wayne, the son of wealthy socialites, witnesses his parents’ murder at the hands of a desperate mugger and swears to avenge their deaths by waging war on all criminals. He grows up to inherit their fortune and the family company, using the money to fund charitable efforts and to reside in stately Wayne Manor. By night, he becomes Batman, ridding the Gotham City streets of menacing foes like the Joker, the Riddler, and Two-Face. He is aided in his fight by his sidekick Robin, Batgirl, and Commissioner Gordon, as well as his butler Alfred Pennyworth. His most enduring love interest is Selina Kyle, who is also known as the notorious cat-burglar, Catwoman. Batman eschews lethal weaponry such as guns, instead preferring to outwit his foes using his intellect to bring them to justice.
While the key details of Batman’s backstory have remained unchanged for almost seventy-five years, his characterization has changed to suit the ever-evolving expectations of a superhero. When the character debuted in the Silver Age of comics—the decades between 1950 and 1970—he was a sunny, pulpy character: he was billed as the “World’s Greatest Detective” and performed as such, while reflecting what is considered to be a more innocent time. His villains were grand, but he outsmarted them using his intelligence and science. The introduction of the Comics Code Authority in 1954 restricted not only the way that stories were presented but also the types of stories that could be presented. For instance, concealed weapons were forbidden, stories were required to have “morals,” and kidnapping and excessive violence were forbidden. As such, Batman’s stories began incorporating elements of science fiction. As the comics demonstrate, Batman famously repels aliens and an island of animatronic dinosaurs during this period. Also, female characters in the Batman stories of this time are poorly treated. The villain Catwoman had to be shelved due to regulations regarding women and violence, while the original Batwoman was brought on as a potential love interest to quiet the growing assertion of conservative culture warriors that Batman and Robin were, in fact, lovers. When this version of Batwoman was deemed unnecessary, she was written out. This period is also famous for Batman having “batsuits” with heretofore unseen special properties, such as fireproofing and thermal heating.
Modern portrayals of Batman show him as a deeply flawed, psychologically scarred hero. During the 1980s the Comics Code’s influence was waning, and writers like Frank Miller took advantage of this to tell brutal, psychological stories. Haunted by the murder of his parents, a modern Batman is dangerous and calculating. He has returned to his roots as a skilled detective and fighter, which has made him suspicious and paranoid. He is often depicted as having calculated how to defeat his allies, should the need arise, with contingency plans for everyone from Robin to Superman. Modern writers have a young Bruce Wayne train as a ninja before returning to Gotham to become Batman, so greater emphasis is placed on his stealth and fighting skills. The batsuit has reflected this change as well, shifting from a cloth/spandex suit to one that is very clearly body armor, built to withstand bullets and knives.
He is also haunted by his mistakes. After the death of Jason Todd, the second sidekick to go by the codename Robin, Batman spirals into anger and depression over not being able to prevent Jason’s death at the hands of the Joker. For the next decade, Jason’s murder haunts Batman alongside that of his parents as his greatest failure. He puts Jason’s costume on display in the Batcave as motivation. In the 2008 Christopher Nolan film The Dark Knight, Batman and Commissioner Gordon conspire to hide the truth of the popular District Attorney Harvey Dent’s descent into madness so that Gotham City will have a symbol of hope. While that decision is for the good of the city, it leads to Bruce Wayne’s reclusion and an eight year hiatus as Batman. Such dark, psychological stories would never have been allowed during the heyday of the Comics Code Authority.
Just as the portrayal of Batman has shifted to meet the current expectations of a superhero, so too have the depictions of the characters around him, both allies and enemies. During the Silver Age, Batman’s associates are, like Batman himself, light-hearted. Characters like Ace the Bat-Hound and the Bat-Mice were introduced to bring in more young readers, though these characters were rarely seen after 1964. Issues were built around a villain-of-the-week who is purely evil and has no outside motivation. These stories also tend to be episodic with no story arcs or even character arcs. The Joker is originally a calculating murderer, but his character becomes a gleeful trickster to comply with the Code.
As readers matured, the creative forces driving the various Batman outlets were able to tell more complex, meaningful stories. Thus, in modern portrayals, Batman’s associates deal with real, lasting consequences and changes. Beginning with Frank Miller’s The Dark Knight comic series, Batman’s friends begin their trials. Dick Grayson, the original Robin, grows up and goes to college, being replaced by the ill-fated Jason Todd. He becomes a hero in his own right, going by the codename Nightwing and becoming the leader of the Teen Titans. In the seminal 1988 graphic novel The Killing Joke, Batgirl is partially paralyzed by the Joker, who shoots her through her spine as part of an effort to drive her father, Commissioner Gordon, insane. This condition lasts until the DC-Universe-wide reboot in 2011, and she is now able to walk and has resumed the mantle of Batgirl. The Joker himself has been given many different backstories, all of them horrific. Filmmakers give a nod to the Joker’s varied backstories in the film The Dark Knight by having the Joker give conflicting accounts of how he received his trademark scars. Catwoman is originally just a bored housewife who turns to crime, but beginning in the 1980s her story retroactively changes to her being a prostitute who turns to burglary to buy freedom for herself and her sister. Once a staunch villain of Batman, this new version of the character is portrayed more as an antihero; though she is not necessarily an upstanding citizen, the new Catwoman will join forces with Batman to fight evil when it suits her. These stories appeal to an audience craving depth and substance to their characters, far different from the Pre-Vietnam War era Batman stories.
While the key details to the Batman story never change, the way the character has been presented has changed over time, as has the way his associated characters have been presented. It is perhaps this adaptability that has allowed Batman to flourish in popularity for almost seventy-five years, with no signs of that popularity waning. As the demographic for Batman’s stories matures, the power wielded by the Comics Code Authority has diminished, making darker, more meaningful stories possible. Previously one dimensional characters were given subtleties and nuances, much in the way modern film versions depict the heroes of old, from Odysseus to Sherlock Holmes. As society’s norms change, this change is reflected in the way films, stories, and comic books depict superheroes. With all the changes occurring in culture worldwide, who knows what the next generation’s Batman will be like?
Online Compare-and-Contrast Essay Alternatives
Deborah Tannen compares and contrasts conversation styles in “Sex, Lies and Conversation: Why Is It So Hard for Men and Women to Talk to Each Other?
Alex Wright examines communication patterns, old and new, in “Friending, Ancient or Otherwise.”
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The city of Sparta in the Peloponnese was important in the story of archaic and classical Greece, but the complex interweaving of myth and history, by both admirers and detractors, has made it particularly difficult to establish the reality of events. Sparta’s military prowess became legendary following its stand against the invading Persian army at the Battle of Thermopylae in 480 BC. The Spartans went on to dominate the Peloponnese, rivalling and eventually triumphing over Athens during the inter-Greek conflict known as the ‘Peloponnesian War’. A fascination with the Spartan way of life, which was considered exceptional even by contemporaries, has endured throughout the ancient and modern world. The harsh and rigorous educational system and life-training (agoge) of all Spartans, male and female, and the communal lifestyle of Spartan citizens, supported by enslaved or dependent peasants, the helots, have been considered both cautionary tales and models of behaviour.
Stories about Sparta loom large in the literature, but archaeologically the city was uninspiring, as Thucydides, the 5th century BC Greek historian, writes:
Suppose the city of Sparta to be deserted, and nothing left but the temples and the ground-plan, distant ages would be very unwilling to believe that the power of the Lacedaemonians [Spartans] was at all equal to their fame ... their city is not built continuously, and has no splendid temples or other edifices...
(A History of the Peloponnesian War, I.10)
A view of modern Sparta towards Mount Taygetos. The temple of Artemis Orthia is in the foreground. User:Ulrichstill, 2005
Today, even the few surviving remains of the Greek city are rarely visible in archaeological excavations, because of extensive overbuilding by the Roman and then the modern city.
Votive gifts from the sanctuary at Artemis OrthiaHowever, archaeological remains outside the city are easier to find. On the west bank of the river Eurotas outside the city is the Spartan sanctuary of Artemis Orthia. The sanctuary was probably established in the 9th century BC, and by about 700 BC a temple had been built within a paved enclosed area. It continued to be important for centuries. The offerings at the early sanctuary, although small, were often made from expensive and exotic materials brought from far away, such as amber and faience, gold, silver and bronze. The most distinctive gifts discovered were over 100,000 tiny figurines of warriors, animals, worshippers and goddesses made of lead, perhaps from Attica. In the late 6th century BC the temple was rebuilt, probably after being destroyed by flooding, and the sanctuary continued to be important, being rebuilt and enlarged, for centuries. In the Hellenistic period the city walls were expanded to include the sanctuary, and in the Roman period (3rd century AD) a theatre was built in front of the temple for audiences to watch the famous ritual ordeal by flogging (diamatigostis) described by Cicero.
Roman authors describe several versions of the cults origins, but these are simply stories invented to give the Roman practices a long and authentic history. The form of the early Greek rituals and indeed the nature of the goddess herself, whose name was found written on pottery and roof-tiles from the sanctuary, remain uncertain.
The British School at Athens excavation of the Artemis Orthia Temple, 1906-10.
The sanctuary site was excavated between 1906 and 1910 by Richard M. Dawkins, working for the British School at Athens. This was the beginning of a long history of excavations in and around Sparta conducted by the British School. As well as the sanctuary of Artemis Orthia, early excavations revealed the remains of the sanctuary of Athena Chalkioikos one of the most important cult sites of Classical Sparta, and a shrine known as the Menelaion, which was used since the Mycenean period, as well as Classical and Roman stoas, parts of the ancient city wall and a very large theatre with a moveable stage. Excavations continued in the 1920s headed by Arthur M. Woodward (and assisted by, among others, Winifred Lamb, then Honorary Keeper of Greek and Roman at the Fitzwilliam), in the 1970s under Hector Catling, and in the 1980s under Geoffrey Waywell and John Wilkes. The records documenting these excavations, which span over a century, are housed in the Archive of the British School at Athens.
In 1923 a selection of the finds from the Sparta excavations were given by the Greek government, through the British School at Athens, to the Fitzwilliam Museum and to several other museums in the United Kingdom, but the majority of the objects remain in Greece, displayed in the Archaeological Museum in Sparta and the National Archaeological Museum, Athens.
Some material from the sanctuary of Artemis Orthia is displayed in the Fitzwilliam Gallery 21 in showcase 5.
Further reading
R.M. Dawkins (ed.), The Sanctuary of Artemis Orthia at Sparta, Excavated and Described by Members of the British School at Athens 1906-1910, Journal of Hellenic Studies supplement (London, 1929).
J. Boardman, ‘Artemis Orthia and Chronology’, Annual of the British School at Athens 58 (1963) pp.1-8.
P. Cartledge, The Spartans: An Epic History (London, 2002).
H. Waterhouse, The British School at Athens (1986).
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Striking gold in water management
Climate change poses one of the greatest threats to the planet, so how can we better manage our most valuable resource – water? The key to future water management could lie in analysing lessons from the past.
At La Trobe University, researchers Professor Susan Lawrence, Dr Peter Davies and Associate Professor Ewen Silvester are examining the water infrastructure built to sustain the Victorian goldfields in the 19th century.
As mining was reliant upon good water supply, these early pioneers discovered innovative ways to transport water. Their methods informed the development of complex municipal water supplies for cities, leading directly to private ownership laws and today’s water allocation practices.
How miners revolutionised Victoria’s waterways
The Australian Gold Rush began in 1851, and according to Professor Lawrence, it ‘wasn’t a little flash in the pan when everyone went crazy’. In fact, it was a mining bonanza that spanned 50 years and profoundly affected many aspects of Australian life.
Multiculturalism, democracy and modern attitudes to home ownership (the Australian Dream of owning a quarter-acre block) all had their origins in the Gold Rush. So did water management, as Dr Lawrence explains, including ‘the way we use water, the way the Victorian landscape looks today and the way Victorian rivers operate today’.
Miners had to be resourceful. For a start, mining uses large amounts of water, and Victoria isn’t exactly blessed with an abundance of surface water.
There was a lot of mining, too – it was a gold rush, after all. Miners became skilled in constructing catchment systems to capture and store rainwater, diverting it over long distances to where it would be most useful.
This was simple technology, but very effective. As Professor Lawrence explains, miners dug channels (‘water races’) from dams built on gullies and creeks, ‘diverting water sideways across the hills from a very slight gradient to their mining claims’. By 1868, there was a 4,000 km-network of water races criss-crossing the Victorian colony.
That mining expertise resonates today in a different and more pressing context. Professor Lawrence says that miners’ knowledge of rainfall and dam building is invaluable ‘because Victoria, and Australia, generally, has relatively little surface water’.
By contrast, in the Californian goldfields of the 19th century, miners used snowmelts to obtain water and power their mines. In Victoria, Professor Lawrence says, ‘they had to collect the water – it fell. They didn’t have streams and lakes. In Australia, we just have rainfall and we have to store it somewhere. That’s the only way we can obtain water sustainably.’
Lessons from the past
For Dr Davies, researching the Australian goldfields taught him important lessons about appreciating water and being aware of where it originates. ‘These days,’ he says, ‘we turn on a tap and it seems a distant thing. I’ve certainly become aware of the importance of water and how important it is to capture and save as much of it as possible.’
Miners were self-sufficient. In Beechworth, according to Professor Lawrence, ‘they built massive water systems and carried huge quantities of water a long way’. However, large-scale systems like this weren’t universally applied. At Castlemaine, ‘people managed their own water locally and built hundreds of small dams. Each miner would have their own little dam. It was a really different way of using water, like domestic water tanks today.’
At the end of their research, Professor Lawrence and Dr Davies were faced with wider questions about what happened to the water when it entered the landscape in a polluted state from mining.
As they are both archaeologists, they brought in researchers with specialised expertise, primarily geomorphologists and environmental chemists, to uncover where the water went from mining and what the implications are for the present day. Dr Silvester was added to the team, with a view to using chemical techniques to identify contaminants in sludge deposits. This will allow researchers to determine risks to water quality.
How early waterways can shape the future
The team’s research can help Australia’s long-term water use become sustainable. Nineteenth-century goldmining was a technology adapted to a particular water-challenged environment, and if the worst effects of climate change continue to be felt, it can assist us to meet the challenges of tomorrow.
As Professor Lawrence highlights, conservation of water is one of the most important lessons miners can teach us. ‘Even when the miners had all this water and all their systems,’ she says, ‘they still ran out. It was a seasonal supply. They would work while they had water and then they would go and do something else.’
Another critical lesson centres on reuse. As Dr Davies explains, ‘in areas with hills and slopes and gullies, one miner up top would use the water, then the dirty water would flow down and might be left to settle out and clean a bit, before being used by another miner. Sometimes, it might be used by three or four groups as it came down. Reuse was part of their strategy.’
Today, with the far-reaching work of this multidisciplinary team well under way, the answer as to how we might best manage our water supply could be closer than we think.
Professor Susan Lawrence is Head of the Department of Archaeology and History at La Trobe University, and Dr Peter Davies is a research associate in the department. Associate Professor Ewen Silvester is Associate Professor in La Trobe’s Department of Ecology, Environment and Evolution.
See yourself working in archaeology. Find out why La Trobe is Victoria's top-rated university for archaeology research.
Could you help solve future environmental issues? Find out more about our Ecology, Environment and Evolution study options.
Inspired by our research?
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exploring science
Science has come a long way - away from things like astrology and alchemy. Kepler played an important role and the same can be said of Renaissance, Reformation and the exploring done in the Age of Discovery.
But it hasn't been a straight line. Important scientists like Newton and Boyle were active in alchemy and a lot of the stories about great discoveries weren't as straightforward as usually told, like in the case of Copernicus, Snow and Darwin.
Below you find simple scheme of how science could work: the empirical cycle. But the development of new theories doesn't always go in a straight line. Looking at the filters in of science to the right you can easily see that many different factors play a role in the acceptance of new facts and theories.
There's a big difference between experimental and historical science. The latter is more descriptive and isn't based on reproducible experiments (though some experiments can be done to show things could have happened in a certain way).
And even in experimental science reproducibility shouldn't be overestimated. A survey by Nature in 2016 showed that many scientists experience problems with reproducibility. The top two factors mentioned by scientists are selective reporting and pressure to publish. See link nr. 7 for the survey.
1. Wikipedia about the History of science in classical antiquity
2. About The Christian Virtuoso by Robert Boyle
3. Pretty elaborate is Christian foundations of modern science
4. A shorter article is: Christianity and the rise of modern science
5. The idea of a flat Earth (article Wikipedia - see illustration below) wasn't a common in the Middle Ages: see the Myth of the flat Earth
6. For more on the (false) idea of a flat Earth, see links 3-5 on the page Models of the universe
7. Scientists lift the lid on reproducibility - Nature survey of 2016
8. Also use the links on the Dutch page
Exploring science
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1. Every year, more than one billion tons of food are lost worldwide. In industrialized nations, consumers are responsible for most of these losses: 13% of the food purchased in Europe ends up in the garbage, in the U.S., almost 16% is trashed.
2. Extreme weather events are becoming increasingly common: The damage caused by 2016 weather-related events amounted to $44 billion in the U.S. alone; 3.5 million people in El Salvador, Guatemala, Honduras and Nicaragua were affected by food supply disruptions as a result of El Nino.
3. The 500 million-plus smallholders around the world are responsible for 50% of the world’s food supply; in developing countries they are responsible for as much as 80%. However, they are less productive than operations in industrialized countries.
4. Fertile soil is being lost all over the world, due to factors such as deforestation, overgrazing, and mismanagement. More than 200 million hectares of soil in Latin America are severely damaged, and many species of mammals, birds, fish and plants are at risk of extinction.
5. By 2050, the world’s population will have grown to nearly 10 billion: 90% of which will be in Asia and Africa, and 66% of the world will live in cities.
Source: The Future of Agriculture and Food, Handelsblatt Research Institute/Bayer
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Skip to main content
[ "article:topic", "Minkowski diagram", "proper length", "authorname:tatumj", "proper time", "time dilation", "showtoc:no" ]
Physics LibreTexts
15.10: Time Dilation
• Page ID
• We imagine the same railway train \( \sum'\) and the same railway station \( \sum\) as in the previous section except that, rather than measuring a length referred to the two reference frames, we measure the time interval between two events. We’ll suppose that a passenger in the railway train \( \sum'\) claps his hands twice. These are two events which, when referred to the reference frame \( \sum'\), take place at the same place when referred to this reference frame. Let the instants of time when the two events occur, referred to \( \sum'\), be \( t'_{1}\) and \( t'_{2}\). The time interval \( T'\) is defined as \( t'_{2}-t'_{1}\). But the Lorentz transformation is
\[ t=\gamma(t'+\frac{\nu x'}{c^{2}})\]
and so the time interval when referred to \( \sum\) is
\[ T=\gamma T'. \label{15.10.1}\]
This is the dilation of time. The situation is illustrated by a Minkowski diagram in Figure XV.13. While it is clear from the figure that \( T=T'\cos\theta\) and therefore that \( T=\gamma T'\) it is not so clear from the figure that this means that \( T\) is greater than \( T'\) – because \( \cos\theta > 1\) and \( \theta\) is imaginary.
Thus, let us suppose that a passenger on the train holds a 1-metre measuring rod (its length in the direction of motion of the train) and he claps his hands at an interval of one second apart. Let’s suppose that the train is moving at 98% of the speed of light (\( \gamma\) = 5.025). In that case the stationmaster thinks that the length of the rod is only 19.9 cm and that the time interval between the claps is 5.025 seconds.
I deliberately did not word that last sentence very well. It is not a matter of what the stationmaster or anyone else “thinks” or “asserts”. It is not a matter that the stationmaster is somehow deceived into erroneously believing that the rod is 19.9 cm long and the claps 5.025 seconds apart, whereas they are “really” 1 metre long and 1 second apart. It is a matter of how length and time are defined (by subtracting two space coordinates determined at the same time, or two time coordinates at the same place) and how space-time coordinates are defined by means of the Lorentz transformations. The length is 19.9 cm, and the time interval is 5.025 seconds when referred to the frame \( \sum\). It is true that the proper length and the proper time interval are the length and the time interval referred to a frame in which the rod and the clapper are at rest. In that sense one could loosely say that they are “really” 1 metre long and 1 second apart. But the Lorentz contraction and the time dilation are not determined by what the stationmaster or anyone else “thinks”.
Another way of looking at it is this. The interval \( s\) between two events is clearly independent of the orientation any reference frames, and is the same when referred to two reference frames that may be inclined to each other. But the components of the vector joining two events, or their projections on to the time axis or a space axis are not at all expected to be equal.
By the way, in Section 15.3 I urged you to write a computer or calculator programme for the instant conversion between the several factors commonly encountered in relativity. I still urge it. As soon as I typed that the train was travelling at 98% of the speed of light, I was instantly able to generate \( \gamma\). You need to be able to do that, too.
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The Creation Wiki is made available by the NW Creation Network
From CreationWiki, the encyclopedia of creation science
Jump to: navigation, search
Class Malacostraca
Scientific Classification
The class Malacostraca is in the Phylum Arthropoda, which is the largest phylum in the Kingdom Animalia. This class includes more than 20,000 species, which is about 2/3 of all the species in the Subphylum Crustacea. Malacostracan is well known as one of the famous exoskeleton organisms. Its name, malacostraca, means ‘soft shell’ in Greek.
It contains the Order Decapoda (crab, lobster, true shrimp, etc) which lay people recognize as crustaceans. It also contains the Order Isopoda, such as woodlice and sowbugs, which is the only land-based crustaceans.
It is very hard to generalize about this class because it is diverse and varied. [1]
Click picture to see general malacostracan bodyplan.
Malacostracans have a hard exoskeleton typical of crustaceans. Their body is divided into three parts – cephalon, thorax, and abdomen. It may be hard to distinguish between the head and thorax, because they make up the cephalothorax. Every malacostracan except odd species in the Phyllocarida has 5 or 6 segments in its head part, an 8 in thorax, and a 6 in abdomen. The number of odd species is 20, and they have 7 segments in the abdomen. The head has not only mouthparts, but also a pair of antennules and a pair of antennae. They have 10 walking legs and the first pair sometimes forms pincers. Some of them use their abdomen for swimming.[2]
Their typical carapace protects internal gills. Large organisms normally have a well-developed circulatory system. A brain is located near the compound stalked or sessile eyes. It is connected to a few of ganglia through a paired ventral nerve cord. Green glands, in the second antennae, accomplish excretion and osmoregulation. They have a gut for digestion, and a posterior anus on the telson for expelling waste.[3]
Each malacostracan has a specific gender. The female has gonads on its sixth thoracic segment and the male has them on its eighth. The anterior abdominal appendage in a male is used as a reproductive structure which is good at sperm delivery. Some species, such as the peracaridans, brood eggs behind the thorax. Other malacostracans lay eggs. Most species have a nauplius larva stage and the eggs of some species hatch into zoea larvae.[4]
Usually malacostracans live in water
They live in marine water, freshwater, and even on land. Most malacostracans are very active hunters and eat only meat. Organisms which represent many orders have thoracic appendages for catching and crushing food or spearing victim. Several species are parasitic, but they are also scavengers. Herbivorous (organisms which eat plants) also exist.
Most Malacostracans are very active, but there are some benthic burrowing species that remain fairly inactive. [5]
Related References
See Also
Creationwiki biology portal.png
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• Conditions List
Terrorism and War: Talking to Children about it
In today’s world, parents are faced with the challenge of explaining violence, terrorism and war to children. Although difficult, these conversations are extremely important. They give parents an opportunity to help their children feel more secure and understand the world in which they live. The following information can be helpful to parents when discussing these issues:
Listen to Children:
1. Create a time and place for children to ask their questions. Don’t force children to talk about things until they’re ready.
Answer Children’s Questions:
5. Be consistent and reassuring, but don’t make unrealistic promises.
9. Don’t confront your child’s way of handling events. If a child feels reassured by saying that things are happening “very far away,” it’s usually best not to disagree. The child may need to think about events this way to feel safe.
Provide Support:
1. Don’t let children watch lots of violent or upsetting images on TV. Repetitive frightening images or scenes can be very disturbing, especially to young children.
2. Help children establish a predictable routine and schedule. Children are reassured by structure and familiarity. School, sports, birthdays, holidays, and group activities take on added importance during stressful times.
3. Coordinate information between home and school. Parents should know about activities and discussions at school. Teachers should know about the child’s specific fears or concerns.
4. Children who have experienced trauma or losses may show more intense reactions to tragedies or news of war or terrorist incidents. These children may need extra support and attention.
5. Watch for physical symptoms related to stress. Many children show anxiety and stress through complaints of physical aches and pains.
6. Watch for possible preoccupation with violent movies or war theme video/computer games.
7. Children who seem preoccupied or very stressed about war, fighting, or terrorism should be evaluated by a qualified mental health professional. Other signs that a child may need professional help include: ongoing trouble sleeping, persistent upsetting thoughts, fearful images, intense fears about death, and trouble leaving their parents or going to school. The child’s physician can assist with appropriate referrals.
8. Help children communicate with others and express themselves at home. Some children may want to write letters to the President, governor, local newspaper, or to grieving families.
9. Let children be children. They may not want to think or talk a lot about these events. It is OK if they’d rather play ball, climb trees, or ride their bike, etc.
War and terrorism are not easy for anyone to comprehend or accept. Understandably, many young children feel confused, upset, and anxious. Parents, teachers, and caring adults can help by listening and responding in an honest, consistent, and supportive manner. Most children, even those exposed to trauma, are quite resilient. Like most adults, they can and do get through difficult times and go on with their lives. By creating an open environment where they feel free to ask questions, parents can help them cope and reduce the possibility of emotional difficulties.
Make an appointment
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Parts of a Cell By Esteban
Plant Cell vs. Animal Cell
Cell Membrane
Endoplasmic Reticulum
Golgi complex
Cell Wall
The nucleus is an important part of the cell. All Plant and animal cells have nucleus. The nucleus contains DNA. The nucleus also contains a dark area called the nucleolus. The nucleolus is responsible for making ribosomes. Materials cross the double membrane through pores.
The Golgi complex is an organelle that packages and distributes protein. Lipids and proteins are delivered to the Golgi complex to modify them to do different jobs. The final products are enclosed in piece of of the Golgi complex's membrane. It pinches off to form a small bubble. The bubble transports its content to other parts of the cell or out of the cell.
As you may know, all plant cells have cell walls. Animal cells don't have cell walls. Cell walls give support to the cell and is a rigid structure. The cell walls of plants, fungi, archaea, and bacteria are made of different materials. For example, plants and algae have cellulose fiber in the cell wall.
Click here for a video about animal cells and plant cells
Plant cell and animal cells are different in two ways. Plant cells have chloroplasts which photosythesis takes place. Animal cells do not have chloroplasts and don't go through photosythesis. Plant cells also have cell walls. Cell walls are rigid sturctures that protect the plant cell. Animal cells do not contain cell walls. Animal cells only have cell membranes.
All plant and animal cells have a cell membrane. The cell membrane is a protective barrier that separates the cells content from the cell's environment. Cell membranes are made up of proteins and lipids. The cell membrane contains two layers of phospholipids which is a liquid. Each phospholipid has a hydrophobic end and a hydrophilc end.
All plant cells and animal cells have mitochondria. Mitochondria is the main power source of a cell. Mitochondria's purpose is to break down food to release energy. The energy released by mitochondria is stored in a substance called ATP. In mitochondria, the mitochondria contains two membranes. They are the inner membrane and the outer membrane. The inner membrane is where the ATP is produced.
Many chemical reactions happen in the endoplasmic reticulum or ER. It is where proteins, lipids, and other material are made. The ER is either rough or smooth. The rough ER is found near the nucleus. The rough ER also contains ribosomes. The rough ER makes the cell's protein and the delivers these proteins throughout the cell. The smooth ER lacks protein. The smooth ER makes lipids, and breaks down toxic materials that could damage the cell.
Lysosomes are responsible for digestion in a cell. They contain digestive enzymes. They destroy worn out cells or damaged organelles, gets rid of waste,and engulf foreign envaders. Lysosomes are very helpful to the human body. They get rid of waste and get rid of foreign invaders which could harm us. If lysosomes weren't there, then the foreign invaders could harm us.
Organelles that make protein are called ribosomes. Ribosomes are the smallest organelle in a cell. There are more ribosomes than any other organelle in a cell. Ribosomes make protein by assembling chains of amino acids. Ribosomes are usually found in the rough ER. The smooth ER does not contain ribosomes. Ribosomes are also not covered by a membrane.
As you already now, all plant cells have chloroplasts. Animal cells do not have chloroplasts. Chloroplast is an organelle where photosynthesis takes place. Chloroplasts have two membranes and their own DNA. Chloroplasts are green. They are green because chloroplasts contain chlorophyll. Chlorophyll is a green pigment that makes the chloroplast green. It also traps energy of sunlight.
Click here for more information about cells
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Introduction to Industrial Engineering
By Jane M. Fraser
Chapter 12
The past and the future
Return to the Table of Contents.
12.10 Programmable controls, computers, and communication technology
Computation has been a goal since prehistoric times. We use a decimal counting base because humans first used their hands, with ten digits, to count and to compute. The Mayans used a base 20 system, perhaps counting on fingers and toes. Stonehenge, the large stone structure near Salisbury, England, is just one example of a computer for astronomical events. Archaeoastronomy is the study of such ancient sites, including the Great Pyramid in Egypt, Mayan structures in Yucatan, Mexico, and astronomical structures in Chaco Canyon, Arizona. Many sites in the Western United States have rock carvings that function as solar calendars.
We owe a large debt to contributions from Arabic mathematicians, as shown in the Arabic roots of words like algebra and algorithm.
Explorers and travelers needed accurate navigational tools and computation. Geoff Watts wrote about the need for accurate tide charts:
"I was in a West Indies ship running for a bar harbour in Ireland ... when we beat off our gripe, rudder and a great deal of the stern port, and an after part of the keel upon the bar, and had seven feet water in the hold, and was obliged to run on shore to prevent sinking." William Hutchinson, dock master of the Old Dock at Liverpool, knew from experience what could happen if you misjudge the tide.
In the 18th century, ships on their way into port were frequently stranded or holed when they unexpectedly hit a sandbar or rammed the stone sill at the dock entrance. The common methods of predicting the height of the tide were woefully inadequate and such accidents were an occupational hazard.
The modern computer has roots in the invention of digital logic by George Boole (1815-1864) and the designs of the Difference Engine and Analytical Engine by Charles Babbage (1792-1871). Boolean logic allows numerical calculations to be performed by mechanical operations on switches, each of which can be on or off. Babbage and other inventors were hampered by the slowness and lack of precise tolerances of known technologies, but progress continued to be made; numbers from the 1890 US census were tabulated by a punched-card machine invented by Hans Hollerith (1860-1929).
Campbell-Kelly and Aspray also describe the roots of computing in business machines, used for calculating and accounting. They describe developments during the end of the 18th century (page 28):
Two lines of development emerged in this period: The basic technologies of small calculating machines, such as desk calculators, accounting machines, and cash registers, were settled; and a business machines industry was established to build these machines. The U.S. government supported the development of the first large-scale calculating technology, the punched-card system. However, during the nineteenth century neither of these technologies was widespread. Accurate figures are hard to come by, but we know, for example, that Burroughs, the leading accounting machine manufacturer, sold only 236 machines in 1895. Hollerith had almost no business in the 1890s after the census was tallied, and his company was reduced to four employees. But as the new century dawned, these technologies began to catch on.
The invention of the vacuum tube in the early 1900s opened new possibilities. John Mauchly (1907-1980) and J. Presper Eckert (1919-1995) are usually credited with building the first serious computer, the ENIAC, commissioned by the US Department of Defense. It used 18,000 vacuum tubes, consumed huge amounts of electricity, and emitted huge amounts of heat.
An even better on/off switch was invented in 1947 by a team at Bell Laboratories, the transistor. Other crucial inventions include the integrated chip (with transistors and other electronic components embedded in a single piece of silicon, reducing the need for the often faulty soldered connections), the microprocessor (a computer on a chip), and various inventions allowing even more transistors to be packed into a smaller space.
The invention of computers and the growth in their use has been fueled by three types of use:
1. office uses: document preparation; information storage and retrieval; accounting computations and financial records; and the tabulation of data, such as census results.
2. science and engineering uses: calculations for tables, such as the calculation of tide tables; military uses such as the calculation of ballistic flight paths and calculations for the design of atomic bombs and other weapons;
3. manufacturing production and control: automation of production, for example, the Jacquard loom;
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Computer Science Department
School of Computer Science, Carnegie Mellon University
PCB - A Printed Circuit Board Editor User Manual
Andreas Nowatzyk
June 1985
PCB is an integrated router and editor to design printed circuits. It adopts the correct by construction principle, that is it will enforce a certain set of design rules such as copper traces have to maintain a minimal separation, holes have to aligned, etc. . PCB maintains a data base of the desired circuit so that it can make sure that signals of different net cannot be shorted.
Building a PC board usually involves a number of steps, such as placement of the components, routing the various connections, preparing a geometry file for the photographic masks, adding design changes. PCB aids these steps by:
Placement aids : Components can be moved on a graphic screen. For a given placement, the wire densities can be displayed to give hints on how to improve the placement.
Automatic router : Depending on the complexity and density of the circuit, PCB can route up to 95% of all connections without human intervention.
Manual editing facilities : Wires can be entered with a pointing device like a mouse or graphics tablet. Existing wires can be moved without loss of connectivity and the router can be used interactively on a certain connection, on a certain net or on a certain area of the board. There are commands to erase wires on an individual basis or on entire areas.
Output facilities : PCB can generate a CIF file that complies with the MOSIS design rules for 4 layer boards. It takes care of power and ground connections, can improve the wires by removing unnecessary jogs, adds fillets to holes in order to ease the removal of components and calls external supplied pieces of geometry. In addition, topological bitmaps can be plotted directly on a Versatec plotter which is much faster than using CIF for intermediate plots.
Change facilities : The internal database can be updated in order to add or remove nets a list of points that should form an electrical connection , components a particular IC or any other actual device on a PC board or types a generic description for a class of components, say the layout of a 7400 without rebuilding the entire board.
39 pages
Return to: SCS Technical Report Collection
School of Computer Science homepage
This page maintained by reports@cs.cmu.edu
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Coulomb’s Law | Explanation Statement Formulas Principle Limitation of Coulomb’s Law
Explanation of Coulomb’s Law
Charles Augustin de Coulomb
Charles Augustin de Coulomb
It was first observed in 600 BC by Greek philosopher Thales of Miletus, if two bodies are charged with static electricity, they will either repulse or attract each other depending upon the nature of their charge. This was just an observation but he did not establish any mathematical relation for measuring the attraction or repulsion force between charged bodies. After many centuries, in 1785, Charles Augustin de Coulomb who is a French physicist, published the actual mathematical relation between two electrically charged bodies and derived an equation for repulsion or attraction force between them. This fundamental relation is most popularly known as Coulomb's law.
Statement of Coulomb’s Law
First Law
Like charge particles repel each other and unlike charge particles attract each other.
coulomb's law
Second Law
The force of attraction or repulsion between two electrically charged particles is directly proportional to the magnitude of their charges and inversely proportional to the square of the distance between them.
Formulas of Coulomb’s Law
According to the Coulomb’s second law,
1. ‘F’ is the repulsion or attraction force between two charged bodies.
2. ‘Q1’ and ‘Q2’ are the electrical charged of the bodies.
3. ‘d’ is distance between the two charged particles.
4. ‘k’ is a constant that depends on the medium in which charged bodies are presented. In S.I. system, as well as M.K.S.A. system k=1/4πε. Hence, the above equation becomes.
5. The value of ε0 = 8.854 X 10-12 C2/Nm2.
Hence, Coulomb’s law can be written for medium as,
Then, in air or vacuum εr = 1. Hence, Coulomb’s law can be written for air medium as,
The value of εr would change depends on the medium. The expression for relative permittivity εr is as follows;
Principle of Coulomb’s Law
Suppose if we have two charged bodies one is positively charged and one is negatively charged, then they will attract each other if they are kept at a certain distance from each other. Now if we increase the charge of one body keeping other unchanged, the attraction force is obviously increased. Similarly if we increase the charge of second body keeping first one unchanged, the attraction force between them is again increased. Hence, force between the charge bodies is proportional to the charge of either bodies or both.
Now, by keeping their charge fixed at Q1 and Q2 if you bring them nearer to each other the force between them increases and if you take them away from each other the force acting between them decreases. If the distance between the two charge bodies is d, it can be proved that the force acting on them is inversely proportional to d2.
This development of force is not same for all mediums. As we discussed in the above formulas, εr would change for various medium. So, depends on the medium, creation of force can be varied.
Limitation of Coulomb’s Law
1. Coulomb’s law is valid, if the average number of solvent molecules between the two interesting charge particles should be large.
2. Coulomb’s law is valid, if the point charges are at rest.
3. It is difficult to apply the Coulomb’s law when the charges are in arbitrary shape. Hence, we cannot determine the value of distance‘d’ between the charges when they are in arbitrary shape.
4. Video Presentation of Coulomb's Law
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What is Inductor and Inductance | Theory of Inductor
What is Inductor?
Before knowing what is inductor we should first know the definition of inductance.
Definition of Inductance
If a changing flux is linked with a coil of a conductor there would be an emf induced in it. The property of the coil of inducing emf due to the changing flux linked with it is known as inductance of the coil. Due to this property all electrical coil can be referred as inductor. In other way, an inductor can be defined as an energy storage device which stores energy in form of magnetic field.
magnetic field due to current
Theory of Inductor
A current through a conductor produces a magnetic field surround it. The strength of this field depends upon the value of current passing through the conductor. The direction of the magnetic field is found using the right hand grip rule, which shown. The flux pattern for this magnetic field would be number of concentric circle perpendicular to the detection of current.
Now if we wound the conductor in form of a coil or solenoid, it can be assumed that there will be concentric circular flux lines for each individual turn of the coil as shown. But it is not possible practically, as if concentric circular flux lines for each individual turn exist, they will intersect each other. However, since lines of flux cannot intersect, the flux lines for individual turn will distort to form complete flux loops around the whole coil as shown. This flux pattern of a current carrying coil is similar to a flux pattern of a bar magnet as shown.
Now if the current through the coil is changed, the magnetic flux produced by it will also be changed at same rate. As the flux is already surrounds the coil, this changing flux obviously links the coil. Now according to Faraday’s law of electromagnetic induction, if changing flux links with a coil, there would be an induced emf in it. Again as per Lenz’s law this induced emf opposes every cause of producing it. Hence, the induced emf is in opposite of the applied voltage across the coil.
Definition of Self Inductance
Whenever current flows through a circuit or coil, flux is produced surround it and this flux also links with the coil itself. Self induced emf in a coil is produced due to its own changing flux and changing flux is caused by changing current in the coil. So, it can be concluded that self-induced emf is ultimately due to changing current in the coil itself. And self inductance is the property of a coil or solenoid, which causes a self-induced emf to be produced, when the current through it changes.
Explanation of Self Inductance of a Coil
Whenever changing flux, links with a circuit, an emf is induced in the circuit. This is Faraday’s laws of electromagnetic induction. According to this law,
e\;=\;-\;N\frac{d\phi }{dt}\;\cdots \cdots \cdots \cdots \cdots \;(\;1\;)
Where, e is the induced emf. N is the number of turns. (dφ/dt) is the rate of change of flux linkage with respect to time. The negative sign of the equation indicates that the induced emf opposes the change flux linkage. This is according to Len’z law of induction. The flux is changing due to change in current of the circuit itself. The produced flux due to a current, in a circuit, always proportional to that current. That means,
\phi \;=\;Ki
Where, i is the current in the circuit and K is the proportional constant.
Now,\;\frac{d\phi }{dt}\;=\;K\frac{di}{dt}\;\cdots\cdots\cdots\cdots\cdots\;(\;2\;)
Now, from equation (1) and (2) we get,
The above equation can also be rewritten as
- e\;=\;L\frac{di}{dt}\cdot\cdot\cdot\cdot\cdot\cdot\cdot\cdot\cdot\cdot(3)
Where, L (= NK) is the constant of proportionality and this L is defined as the self inductance of the coil or solenoid. This L determines how much emf will be induced in a coil for a specific rate of change of current through it.
Now, from equation (1) and (3), we get,
L\frac{di}{dt}\;=\;N\frac{d\phi}{dt}\;\Rightarrow\;Ldi \;=\;Nd\phi
Integrating, both sides we get,
\int Ldi \;=\;\int Nd\phi \Rightarrow Li = N\phi\;\Rightarrow L\;=\;\frac{N\phi}{i}\cdot\cdot\cdot\cdot\cdot\cdot\cdot\cdot\cdot\cdot(4)
From the above expression, inductance can be also be defined as,
“If the current I through an N turn coil produces a flux of Ø Weber, then its self-inductance would be L”.
A coil can be designed to have a specific value of self-inductance (L). In the view of self-inductance, a coil or solenoid is referred as an inductor. Now, if cross – sectional area of the core of the inductor(coil) is A and flux density in the core is B, then total flux inside the core of inductor is AB.
Therefore, equation (4) can be written as
Now, B = μoμrH Where, H is magnetic field strength, µo and μr are permeability of free space and relative permeability of the core respectively. Now, H = mmf/unit length = Ni/l Where l is the length of the coil. Therefore,
L\; =\;\frac{NA\mu_o\mu_rNi}{li}\; =\;\frac{A\mu_o\mu_rN^2}{l}
Self Inductance Formula
Video presentation on theory of Inductor
Unit of Inductance
Which we derived at equation (3). Where, L is known is self induction of the circuit. In the above equation of inductance, if e = 1 Volt and (di / dt) is one ampere per second, then L = 1 and its unit is Henry. That means, if a circuit, produces emf of 1 Volt, due to rate of change of current through it, one ampere per second then the circuit is said to have one henry self inductance. This henry is unit of inductance.
Mutual Inductance
Inductance due to the current, through the circuit itself is called self inductance. But when a current flows through a circuit nearer to another circuit, then flux due to first circuit links to secondary circuit. If this flux linkage changes with respect to time, there will be an induced emf in the second circuit. Similarly, if current flows through second circuit, it will produced flux, and if this current changes, the flux will also change. This changing flux will link with first coil. Due to this phenomenon emf will be induced in the first coil. This phenomenon is known as mutual inductance. If current i1 flows through circuit 1 then emf e2 is induced in the nearby circuit is given by,
Where, M is the mutual inductance.
If current i2 flows through circuit 2, then emf e1 is induced in the nearby circuit 1 is given by,
Defination of Mutual Inductance
Mutual inductance may be defined as the ability of one circuit to produce an emf in a nearby circuit by induction when current in the first circuit changes. In reverse way second circuit can also induce emf in the first circuit if current in the second circuit changes.
Coefficient of Mutual Inductance
Let’s consider two nearby coils of turns N1 & N2 respectively. Let us again consider, current i1 flowing through first coil produces φ1. If this whole of the flux links with second coil, the weber-turn in the second coil would be N2φ1 due to current i1 in the first coil. From this, it can be said, (N2φ1)/i1 is the weber-turn of the second coil due to unit current in the first coil. This term is defined as co-efficient of mutual inductance. That means, mutual inductance between two coils or circuits is defined as the weber-turns in one coil or circuit due to 1 A current in the other coil or circuit.
Formula or Equation of Mutual Inductance
Now we have already found that, mutual inductance due to current in first coil is,
M\;=\;\frac{N_2\phi _1}{i_1}
Again, if self inductance of first coil or circuit is L1, then,
L_1i_1\;=\;N_1\phi _1\;\Rightarrow \;\frac{L_1}{N_1}\;=\;\frac{\phi _1}{i_1}
M\;=\;\frac{N_2L_1}{N_1}\;\cdots \cdots \cdots \cdots \cdots\;(\;5\;)
Similarly, coefficient of mutual inductance due to current i2 in the second coil is,
M\;=\;\frac{N_1\phi _2}{i_2}
Now, if self inductance of the second coil or circuit is, L2,
L_2i_2\;=\;N_2\phi _2
\Rightarrow \;\frac{L_2}{N_2}\;=\;\frac{\phi _2}{i_2}
Therefore,\;M\;=\;\frac{N_1L_2}{N_2}\;\cdots \cdots \cdots \cdots \cdots \;(\;6\;)
Now, multiplying (5) and (6), we get,
M\;\times \;M\;=\;\frac{N_2L_1}{N_1}\;\times \frac{N_1L_2}{N_2}
\Rightarrow \;M^2\;=\;L_1L_2\;\Rightarrow \;M\;=\;\sqrt{L_1L_2}
This is an ideal case, when whole changing flux of one coil, links to other coil. The value of M practically not equal to √(L1L2) as because whole flux of one coil does not link with other , rather, a part of flux of one coil, links with other coil. Hence practically,
M\;\neq \;\sqrt {L_1L_2}
and\;\frac{M}{\sqrt{L_1L_2}}\;=\;K\;(\;\neq 1\;)
This k is known as coefficient of coupling and this is the ratio of actual coefficient of mutual inductance to ideal (maximum) coefficient of mutual inductance. If flux of one coil is entirely links with other, then value of K will be one. This is an ideal case. This is not possible, but when K nearly equal to unity, that means, maximum flux of one coil links to other, the coils are said to be tightly coupled or closely coupled. But when no flux of one coil links with other, the value of K becomes zero (K = 0), then the coils are said to be very loosely coupled or isolated.
Mutual Inductance of two Solenoids or Coils
Let us assume two solenoids or coils A and B respectively.
mutual inductance
Coil A is connected with an alternating voltage source , V. Due to alternating source connected to coil A, it will produce an alternating flux as shown. Now, if we connect on sensitive voltmeter across coil B, we will find a non zero reading on it. That means, some emf is induced in the coil B. This is because, apportion of flux produced by coil A, links with coil B and as the flux changes in respect of time, there will be an induced emf in the coil B according to Faraday’s law of electromagnetic induction. This phenomenon is called mutual induction. That means, induction of emf in one coil due to flux of other coil is mutual induction.
mutual induction
Similarly, if the alternating voltage source was connected to coil B and induced voltage is measured by connecting voltmeter across coil A, the voltmeter gives a non-zero reading. That means, in this case the emf will be induced in coil A due to flux linkage from coil B. Let us consider coil A and B have turns N1 & N2. If the entire flux of coil A links with coil B, then weber-turns of the coil B due to unit current of coil A, would be (N2φ1)/i1, where, φ1 & i1 is flux and current of coil A. As per definition this is nothing but mutual inductance of coil A & B, M. That is,
Similarly, if the current and flux of the coil B are i2 and φ2.
Then,\;M\;=\;\frac{N_1\phi _2}{i_2}
Inductances in Series
Let’s coil or inductance A and B are connected in series. The self inductance of coil A , is LA and that of coil B is LB. Now again consider, M is the mutual inductance between them. There may be two conditions.
1. The direction of flux produced by both coil will be in same direction. In that case, the flux of coil B links will be coil A, will be in same direction with the flux produced by coil A, itself. Hence, the effective inductance of coil A will be LA + M.
At the same time, the flux of coil A, links with coil B will be in same direction with self flux of coil B. Hence, the effective inductance of coil B will be LB + M.
Hence total effective inductance of the series connected inductors A and B will be nothing but,
2. Now, if direction of instantaneous flux at coil A and B are in opposite, then flux of coil B linking with coil A, will be in opposite direction of flux produced by coil A itself. So, effective inductance of coil A will be LA - M.
In the same way, the flux of coil A which links with coil B, will be in opposite direction of self flux of coil B.
Hence, effective inductance of coil B will be, LB - M.
So, total inductance in series in this case will be,
So, general form of equivalent inductance of two inductors in series in,
Types of Inductor
fixed inductorThere are many types of inductors ; all differ in size, core material, type of windings, etc. so they are used in wide range of applications. The maximum capacity of the inductor gets specified by the type of core material and the number of turns on coil.
Depending on the value, inductors typically exist in two forms, fixed and variable. .The number of turns of the fixed coil remains the same. This type is like resistors in shape and they can be distinguished by the fact that the first color band in fixed inductor is always silver. They are usually used in electronic equipment as in radios, communication apparatus, electronic testing instruments, etc.
The number of turns of the coil in variable inductors , changes depending on the design of the inductor. Some of them are designed to have taps to change the number of turns. The other design is fabricated to have a many fixed inductors for which, it can be switched into parallel or series combinations. They often get used in modern electronic equipment.
Core or heart of inductor is the main part of the inductor. Some types of inductor depending on the material of the core will be discussed.
Ferromagnetic Core Inductor or Iron-core Inductors
ferromagnetic inductor
This type uses ferromagnetic materials such as ferrite or iron in manufacturing the inductor for increasing the inductance. Due to the high magnetic permeability of these materials, inductance can be increased in response of increasing the magnetic field.
At high frequencies it suffers from core loses, energy loses, that happens in ferromagnetic cores.
Air Core Inductor
air core inductor
Air cored inductor is the type where no solid core exists inside the coils. In addition, the coils that wound on nonmagnetic materials such as ceramic and plastic, are also considered as air cored. This type does not use magnetic materials in its construction.
The main advantage of this form of inductors is that, at high magnetic field strength, they have a minimal signal loss. On the other hand, they need a bigger number of turns to get the same inductance that the solid cored inductors would produce. They are free of core losses because they are not depending on a solid core.
Toroidal Core Inductor
toridal inductor
Toridal Inductor
Toroidal Inductor constructs of a circular ring-formed magnetic core that characterized by it is magnetic with high permeability material like iron powder, for which the wire wounded to get inductor. It works pretty well in AC electronic circuits' application.
The advantage of this type is that, due to its symmetry, it has a minimum loss in magnetic flux; therefore it radiates less electromagnetic interference near circuits or devices. Electromagnetic interference is very important in electronics that require high frequency and low power.
Laminated Core Inductor
laminated core inductor
Laminated Core Inductor
This form gets typified by its stacks made with thin steel sheets, on top of each other designed to be parallel to the magnetic field covered with insulating paint on the surface; commonly on oxide finish. It aims to block the eddy currents between steel sheets of stacks so the current keeps flowing through its sheet and minimizing loop area for which it leads to great decrease in the loss of energy. Laminated core inductor is also a low frequency inductor. It is more suitable and used in transformer applications.
Powdered Iron Core
powdered iron core
Powdered Iron Core
Its core gets constructed by using magnetic materials that get characterized by its distributed air gaps. This gives the advantage to the core to store a high level of energy comparing to other types. In addition, very good inductance stability is gained with low losses in eddy current and hysteresis. Moreover, it has the lowest cost alternative.
Another Classification of Inductor
Coupled Inductor
It happens when inductors are related to each other by electromagnetic induction. Generally it gets used in applications as transformers and where the mutual inductance is required.
RF Inductor
Another name is radio frequency of RF inductors . This type operates at high frequency ranges. It is characterized by low current rating and high electrical resistance. However, it suffers from a proximity effect, where the wire resistance increases at high frequencies. Skin effect, where the wire resistance to high frequency is greater than the electrical resistance of current direct.
Multi-Layer Inductor
Here the wounded wire is coiled into layers. By increasing the number of layers, the inductance increases, but with increasing of the capacitance between layers.
Molded Inductor
The material for which it stands from, is molded on ceramic or plastic. Molded inductors are typically available in bar and cylindrical shapes with a variety option of windings.
The main purpose of it is to block high frequencies and pass low frequencies. It exists in two types; RF chokes and power chokes.
Applications of Inductors
In general there are a lot of applications due to a big variety of inductors . Here are some of them. Generally the inductors are very suitable for radio frequency, suppressing noise, signals, isolation and for high power applications.
More applications summarized here:
1. Energy Storage
2. Sensors
3. Transformers
4. Filters
5. Motors
The use of inductors somehow is restricted due to its ability of radiation of electromagnetic interference. In addition, it is a side effect which makes inductor deviate a little bit from it is real behavior.
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Youm-e-Takbeer: The day of greatness
On May 28, 1998, Pakistan successfully tested five nuclear devices as a direct response to a series of nuclear test explosions by India. This day is celebrated annually in Pakistan as Youm-e-Takbeer, which means the day of greatness, and as the National Science Day, to celebrate Pakistan’s scientific achievements.
The importance of Youm-e-Takbeer
To better appreciate the significance of Youm-e-Takbeer, we have to understand how and why Pakistan was compelled to develop a nuclear weapons program in the first place.
Yes, India’s explosion of the nuclear bomb in 1974, and subsequent explosions of 1998 were the most critical factors. But the loss of East Pakistan, the continued Indian intransigence, and its creeping occupation of territory in Kashmir created an environment of fear and insecurity for Pakistan, which forced them to develop a nuclear weapons program to discourage further Indian belligerence.
The purpose of this article is to provide a better understanding of the history of the conflicts between India and Pakistan that led to the nuclearization of Pakistan.
The Jammu and Kashmir Dispute
During Kashmir’s 1946 general elections, the Muslim Conference, which was in favor of Muhammad Ali Jinnah’s vision for a separate independent Muslim state, was voted into power.
The British accepted the demand of Muslims for an independent state in June 1947. The new nation would be made up of Muslim majority areas, which included Kashmir. The Hindu Congress Party, and the Muslim League accepted the plan.
Less than a year after their independence, India and Pakistan fought their first war over Kashmir. The war ended in the United Nations, where a resolution was passed demanding that Kashmiris be given a vote to determine their future, which India refused to implement.
On September 6, 1965 Indian troops crossed the international border into Pakistan. The battle for Kashmir had turned into a full-scale war with India attempting to take control of Lahore, Pakistan’s second largest city at the time. Despite having the larger army, India could not defeat Pakistan, and the war officially ended in stalemate.
“Pakistan will fight, fight for a thousand years…”
In February 1964, Pakistan’s Foreign Minister Zulfiqar Ali Bhutto addressed the UN Security Council and warned them that if India developed a nuclear bomb, Pakistan would also develop it.
In 1972, having received credible intelligence that India was pursuing a nuclear weapons program, Bhutto is reportedly to have said, “Pakistan will fight, fight for a thousand years. If India builds the bomb… we will eat grass, even go hungry, but we will get one of our own… We will have no other Choice!”
In his book, The Myth of Independence, Bhutto stated that it was necessary for Pakistan to acquire the fission weapon, to deter a nuclear-armed India.
After the 1948 and 1965 experiences, Pakistanis feared that it would not be long before India launched another attack in an attempt to disintegrate Pakistan. Their fears were realized in November 1971, when the Indian army, taking advantage of a political conflict between East and West Pakistan, attacked East Pakistan. Although India failed to destroy Pakistan completely, it did succeed at splitting the nation in half. East Pakistan was lost to Indian interference in a sovereign country on December 16, 1971.
Smiling Buddha (Pokhran-I)
On May 18, 1974, India tested their first nuclear bomb in an operation code named “Smiling Buddha,”or Pokhran-I.
India’s global power ambition created a security dilemma for Pakistan.
Pokhran-I forced then Prime Minister, Zulfiqar Ali Bhutto to inform the world that “Pakistan was exposed to a kind of ‘nuclear threat and blackmail’ unparalleled elsewhere (…) If the world’s community failed to provide political insurance to Pakistan and other countries against the nuclear blackmail, these countries would be constraint to launch atomic bomb programs of their own! (…) Assurances provided by the United Nations were not ‘Enough!'”
Pakistan learned a difficult lesson from the loss of East Pakistan; that it could not rely on the international community for support if confronted by an Indian nuclear threat. Unwilling to be blackmailed, Bhutto made it his mission to develop a nuclear weapon for the sole purpose of deterring India’s nuclear aggression.
May 11, 1998, Operation Shakti (Pokhran-II)
On May 11, 1998 India tested five nuclear bombs. These tests were conducted at a time when conflict in Kashmir was once again escalating.
Recently speaking to students at National Defense University, General Rashid Qureshi, then a Brigade Commander in Kashmir, recalled that Indian troops fired day and night across the Line of Control (LoC) after exploding the nuclear bomb.
There was an environment of insecurity all over Pakistan. This insecurity grew on May 26, 1998, with further clashes. The fear in Pakistan was that India had demonstrated their nuclear capability, what would now stop them from blackmailing or bullying Pakistan in an attempt to take control of Kashmir? And what guarantee would Pakistan have that India would stop at Kashmir?
May 28, 1998, Chaghai-I
The Indian explosions forced Pakistan to make a tough decision. Do not respond to India’s tests and thereby risk Indian aggression and the possibility of a military confrontation, or respond and deter any belligerent designs towards Pakistan?
On May 28, 1998, despite a tremendous amount of international pressure, Pakistan tested its nuclear devices as a direct response to Indian action.
According to General Qureshi, after Pakistan’s response, there was an eerie silence in the whole of Kashmir, with not a single shot fired across the LoC.
Youm-e-Takbeer, also known as the National Science Day, is celebrated because on this day, Pakistan successfully demonstrated their scientific capability, and brought stability to the region by deterring the threat of India’s nuclear bomb.
By testing the bomb Pakistan made full-scale war with India redundant.
Although India did amass more than 500,000 troops to Pakistan’s Eastern border during Operation Parakram in 2001, the Indian dream of capturing any part of Pakistan including Kashmir, by force, is now dead.
Pakistan’s scientific achievements continue to keep India at bay, promoting peace and stability. Pakistan’s most recent development of the Nasr short-range nuclear capable missile is an example of just that.
It is widely believed that India devised the Cold Start Doctrine,with the purpose of engaging in a limited war. The Indian thinking behind the limited war doctrine was that although Pakistan has been able to deter them at the nuclear level they still had space at the conventional level. Pakistan quickly plugged this gap by developing Nasr, “pour[ing] cold water” on Cold Start.
Image: Leon Neal, Getty
Posted in , History, India, India-Pakistan Relations, Nuclear, Nuclear Weapons, Pakistan
Muhammad Umar
Muhammad Umar
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6 thoughts on “Youm-e-Takbeer: The day of greatness
1. Alhamdulillah! We, the Pakistanis, faced the world-challenges bravely and became an atomic power.
2. Very sad to see any country take pride in the development of nuclear weapons be it Pakistan, India or any other. To claim it as scientific achievement reflects a mindset that sees science not as a tool of human progress and development but destruction. If we are to extend this logic Germany, japan and other countries at the cutting edge of science and technology are pygmies in terms of scientific progress. No one seems to read history or learn any lesson from the collapse of the once mighty Soviet Union which went under as its economy could not sustain the weight of its military ambitions. Will history repeat itself, one wonders.
3. Daruwala, it is a point of pride when a country that has already been broken into two by an adversary five times its size is able to deter it from further aggression. And if you look at what is happening today from a historical perspective, India is behaving very much like the Soviet Union, definitely as ambitious as the Soviets were during the late 60s and early 70s. India has made their extra-regional ambitions very clear, they are expanding their sea-based capabilities at an alarming rate, now patrolling in the East and South China Sea–hoping to expand further into the Arabian sea via the Chabahar port. Not to mention the growing range of their ICBMs (the Agni-V can reach parts of North America). If they stay on this path and try to grow too big too fast they might also end up collapsing like the Soviets. PM Modi has already announced increasing the defense budget, I wonder how soon before India is spending 12-15 percent of their GDP on defense. It took the soviets nearly two decades to get to that point. Like you said, “will history repeat itself, one wonders.”
4. Dear Umar, you lost the plot somewhere and went off on a tangent. Nuclear Weapons are no guarantee against State failure, was the crux of my argument. The biggest threat to Pakistan comes from its home grown terrorists who cannot be defeated with nuclear weapons.
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To What Extent Did The Ww2 Change The Lives Of Black Americans?
921 words - 4 pages
To what extent did the WWII change the lives of Black Americans?
The Second World War has caused many changes in America. The fight against Nazis in Europe demonstrated that US suffered from the same problem of racism and the white supremacy and that something had to be done.
During the wartime many African Americans had to move from Southern farms to Northern and Western cities, as there was a lack of jobs because of the increase of machinery in farming industry. At the same time, new factories that produced war equipment needed more labourers as most white men had left America to fight in WWII and it gave Black Americans an opportunity to find new jobs in those spheres, but ...view middle of the document...
Yet, in Tuskegee there were blacks trained as pilots and around 600 of them had served by 1945. Unfortunately, black soldiers returning from the war were treated with disrespect and it was very hard for them to find a job after they quit service, but there still were some great changes in the attitude towards African Americans. Firstly, these opportunities of going abroad allowed Black Americans to see the lack of segregation there and it inspired them to defeat racism in US as well. Black newspapers widely campaigned for a Double Victory over fascism in Europe and racism in US, so many people were aware as it was announced in media. Secondly, it forced all armed forces to move towards equal treatment. No one rejected separation though, but in 1948 Truman ordered the final desegregation and it was the end of discrimination in army.
World War Two affected civil rights campaigns a lot. Considering unsuccessful experience in WWI when black people had suspended all their campaigns believing in improvements but getting nothing, they continued to work in campaigns against discrimination. The NAACP continued to fight for equality in courthouses and schools. In 1944 the NAACP won a major case in Smith vs. Allwright, which outlawed the white primacy. It inspired other African Americans to take a part in the NAACP actions so by the end of WWII the number of the members increased from 50,000 to 450,000 and percentage of voting registered from black people increased from 7% to 12%. It wasn’t the only civil rights organization to come to prominence after the war. The CORE is the campaign founded by James Farmer in 1942 and their aim was to challenge segregation peacefully. Unlike...
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Where Is the Great Barrier Reef?
Where Is the Great Barrier Reef?
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In this Where Is? title, kids can explore the Great Barrier Reef--big enough to be seen from space but made up of billions of tiny living organisms. The Great Barrier Reef, off the coast of Australia, is the world's largest coral reef system. Stretching more than 1,400 miles, it provides a home to a wide diversity of creatures. Designated a World Heritage Site, the reef is suffering from the effects of climate change but this fascinating book shows this spectacular part of our planet.
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Home » What's New » An In-depth Look at Color Blindness
An In-depth Look at Color Blindness
Color blindness is typically a genetic condition which impairs someone's ability to distinguish between shades of color. Color blindness is a result of a dysfunction of the cones in the eye's retina, generally damaging a person's capability to differentiate shades of red or green, but possibly affecting the ability to see other hues also.
The discernment of color is dependent upon the cones found within the retina of the eye. Humans are generally born with three kinds of pigmented cones, each perceiving different wavelengths of color tone. This is comparable to the wavelengths of sound. When it comes to colors, the length of the wave is directly linked to the resulting color. Short waves produce blues, medium-length waves produce green tones and longer waves are seen as reds. Which type of cone is missing has an impact on the nature and level of the color blindness.
Green-red color blindness is more frequent among males than in females because the genetic encoding is linked to gender and is recessively inherited.
Some individuals acquire color vision deficiencies later in life as a result of another condition including injuries, cataracts and especially macular degeneration. Thankfully, it might be possible to reverse the condition once the cause is treated
There are several evaluation methods for color blindness. The most widely used is the Ishihara color exam, named after its designer. For this test a plate is shown with a group of dots in a circle in different colors and sizes. Within the circle appears a digit in a particular tint. The patient's capability to make out the number within the dots of clashing tones determines the level of red-green color vision.
Even though hereditary color vision deficiencies can't be corrected, there are some measures that can help to make up for it. Some evidence shows that using colored contacts or glasses which minimize glare can help people to perceive the differences between colors. Increasingly, computer programs are being developed for regular PCs and even for smaller devices that can assist users to enhance color distinction depending upon their particular condition. There are also exciting experiments being conducted in gene therapy to enhance the ability to distinguish colors.
The extent to which color vision problems limit an individual depends on the kind and degree of the condition. Some patients can adapt to their condition by familiarizing themselves with substitute cues for colored objects or signs. For instance, many individuals are capable of learning the order of traffic signals or contrasting objects with color paradigms like the blue sky or green plants.
If you suspect that you or a family member might be color blind it's important to see an eye doctor. The earlier the condition is diagnosed, the easier it will be to manage. Feel free to call our Manhattan, NY eye doctors for additional details about color blindness.
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The History of Robots: From the 400 BC Archytas to the Boston Dynamics' Robot Dog
Take a journey through the long history of robots, from the 4th Century BC to today.
1, 2, 3, 4
Robots have fascinated and preoccupied human minds for centuries - from ancient tales of stone golems, to modern science fiction. Though the word "robot" was only officially penned in 1921 by Karel Čapek, mankind has endeavored to create autonomous machines since as far back as the 4th Century BCE.
Today, robots are widely used across a variety of industries, aiding in the manufacturing of vehicles and more. According to the International Federation of Robotics, in 2015 there were as many as 1.63 million industrial robots in operation worldwide, and that number continues to grow steadily each year.
Here's a brief history of how robotics have evolved and grown from the early imaginings of 400 BCE, to the global resource they are today.
Ancient Robots: Archytas' Pigeon, Ctesibius' Clepsydra, and More
The earliest beginnings of robotics can be traced back to Ancient Greece. Aristotle was one of the first great thinkers to consider automated tools, and how these tools would affect society at large.
It was in 400 BCE that the first automaton was designed by Archytas of Tarentum, who is today considered the father of mathematical mechanics. Archytas' Pigeon was a steam-powered autonomous flying machine. Its wooden structure was based on the anatomy of a pigeon, and contained an airtight boiler for the production of steam. The steam's pressure would eventually exceed the resistance of the structure, allowing the robotic bird to take flight.
Source: Marie-Lan Nguyen/Wikimedia Commons
In 250 BCE, Ctesibius created a clepsydra, or water clock, sporting a number of elaborate automatons. Though water clocks had been in use for centuries at that point all over the world, it was during this period that Greek and Roman inventors began to update the basic designs of the clocks with features like bells, gongs, and moving figurines. Ctesibius' design allowed for the dropping of peddles onto a loud gong, effectively making it the first alarm clock as well as an example of early automaton design.
But it wasn't just the ancient Greeks and Romans who were experimenting with robotics. There are accounts of automatons from ancient China, like a passage in Lie Zi from the 3rd Century BCE which describes a singing and dancing robot that performed for King Mu of Zhou. According to the text, the robot was built by an inventor named Yen Shih out of wood and leather.
Source: King muh/Wikimedia Commons
11th Century to the 15th Century: Humanoid Automatons and da Vinci's Knight
Development of autonomous technologies continued well into the 11th Century and beyond throughout the world. One of the most important inventors during this period was Ismail al-Jazari, an engineer and mathematician from the golden age of Islam. Al-Jazari is credited with the creation of segmental gears and is considered by many to be the father of robotics. Many of his robotic creations were powered by water, and included everything from automatic doors to a humanoid autonomous waitress who could refill drinks.
Al-Jazari's influence is particularly apparent in the later work of Leonardo da Vinci. In 1495 the famous Italian artist and painter designed an autonomous knight, which featured a series of pulleys and gears that allowed it to move its arms and jaw, as well as sit up. The humanoid robot was informed in many ways by da Vinci's own research on human anatomy, and was apparently used as entertainment at parties by da Vinci's patron, Lodovico Sforza.
Source: Erik Möller/Wikimedia Commons
16th Century to the 18th Century: Flying Robots and Musical Automatons
The creation of robots which were mainly designed for entertainment purposes became ever more popular between the 16th and 18th centuries. Though these automatons were created to entertain, it's important not to treat their designs flippantly. Many of the technologies used in these devices paved the way for more sophisticated machines later on.
One such creation was an iron eagle made by German mathematician Johannes Müller von Königsberg, AKA Regiomontanus. Not a great deal is known about the construction of Regiomontanus' eagle, apart from the fact that it was made of wood and iron sometime in the 1530s. In 1708 author John Wilkins wrote an account of the robot eagle, claiming it had flown to greet the Prussian emperor and returned to Regiomontanus. Von Königsberg is also credited as having created a robotic fly which was also capable of flight.
Another key figure of this time in the creation of entertaining and insutrial machines was Jacques de Vaucanson. In 1737 Vaucanson created The Flute Player - a life-sized humanoid automaton that could play up to 12 different songs on the flute. The automaton used a series of bellows to "breathe", and had a moving mouth and tongue that could vary the airflow, allowing it to play the instrument.
Vaucanson's most memorable achievement, however, was his Digesting Duck. The duck was notable not only for being an amusing device that appeared to eat and poop, but also as it is often considered the first device to utilize rubber tubing.
The 19th Century: Chess-Playing Machines and Early Experiments With Speech
The 19th Century saw the popularity of automatons as touring attractions and oddities, which would enchant and inspire audiences across the globe. A popular type of automaton at this time was the chess-playing robot. The most famous of these creations was The Turk, built by Wolfgang von Kempelen in the 1770s and which toured until 1854. Though it appeared as though The Turk could play chess, the device was revealed to be a fraud that was operated by a chess player concealed within its box.
Despite the elaborate ruse of The Turk, and the similar devices which appeared in its stead, the central conceit provided the inspiration for true chess-playing machines which would debut in the early 20th Century.
One remarkable machine from the 19th Century which most certainly was not a hoax, however, was the Euphonia - a speaking, singing robot which was operated through an early form of text-to-speech technology. Euphonia was created by Austrian mathematician and inventor, Joseph Faber. The machine featured a humanoid feminine face connected to a keyboard, where the face's lips, jaw, and tongue could be controlled. A bellows and ivory reed provided the machine's voice, and pitch and accent could be altered through a screw in the face's nose.
Euphonia was the culmination of 25 years of work for Faber, and debuted to audiences in 1846. Sadly, Victorian audiences were too unsettled by the machine's blank stare and spooky, whispered voice and the device faded into obscurity.
The Early 20th Century: El Ajedrecista, Eric, and Gakutensoku
While The Turk was revealed as a fraud, the early 20th Century saw the creation of the first true chess-playing robots. Built in 1912 by Leonardo Torres y Quevedo, El Ajedrecista (directly translated as "The Chess Player") was the first real chess-playing robot and is considered by some to be a precursor to video games. The device was capable of playing an endgame against a human opponant, and featured an electrical circuit and a system of magnets which moved the pieces. It debuted at the 1914 World's Fair in Paris to great excitement and acclaim.
Source: MdeVicente/Wikimedia Commons
1928 saw the creation of the first British robot, named Eric. Eric was created by engineer Alan Reffell and World War I veteran Captain William Richards. Operated by two people, the robot could move its head and arms, and could speak via a live radio signal. Its movements were controlled by a series of gears, ropes, and pulleys and the robot reportedly spat sparks from its mouth. As an homage to the Čapek's 1921 play Rossumovi Univerzální Roboti - where the term "robot" was first officially coined - Eric had the letters R.U.R. engraved into its chest.
Source: Unknown/Wikimedia Commons
The following year saw the debut of the first Japanese robot - Gakutensoku. Built in 1929 by biologist Makoto Nishimura, Gakutensoku was over seven feet (2.1 meters) tall and could change its facial expressions through the movement of gears and springs in its head. Gakutensoku's greatest achievement, however, was its ability to write Chinese characters. Sadly, the robot went missing while on tour in Germany.
The 1940s: Asimov's Laws of Robotics and the First Artificial Neural Networks
While the 1920s saw the introduction of the term "robot", it wasn't until Isaac Asimov's 1942 short story Runaround that the term "robotics" appeared. In this story, Asimov laid out his famous three laws of robotics - that robots must not harm humans, that they must obey orders from humans, and that they must protect themselves from threats provided their self-preservation doesn't break either of the first two laws. Though written in fiction, these laws provided the basis for many of the ethical questions surrounding robots and autonomous technologies, and are still referred to today.
The 1940s also saw the creation of the first artificial neural networks. In 1943 Warren McCulloch and Walter Pitts created a basic neural network using electrical circuits to better understand how neurons operate in the brain. Their experiments paved the way for the first autonomous robots that could display complex behavior, thanks to the use of artificial neural networks.
In 1948 and 1949 William Grey Walter created two such robots - Elmer and Elsie. Nicknamed "tortoises", the robots could respond to and move towards light, guiding themselves to their recharging stations when their batteries were low.
The 1950s: The Turing Test and the Unimate
Another landmark moment in the history of robotics occurred in 1950, when Alan Turing outlined his test of a machine's artificial intelligence. The Turing Test has become the benchmark of AI, in that it measures to which degree a machine's intelligence is equal to or indistinguishable from that of a human. In its simplest form, the purpose of the test is to determine whether or not a machine can think. His work created a necessary framework for the establishment of the field of Artificial Intelligence in Dartmouth College in 1956.
The 1950s also saw the creation of the first industrial robot - the Unimate. The patent for the Unimate was filed by George Devol in 1954, and featured a robotic arm capable of transporting die-cast parts and welding them into place. The revolutionary device would soon change the face of the manufacturing industry forever.
Source: UL Digital Library/Wikimedia Commons
The 1960s: The Industrial Robot Revolution
After Devol was granted his patent for the Unimate in 1961, the application of robots in industrial settings progressed rapidly. That same year, General Motors installed Unimate on their assembly line in Ewing, New Jersey. After the success of Unimate at General Motors, it entered full-scale production in 1966.
The 1960s saw a number of innovations and expansions on the core idea of Devol's robotic, industrial arm. In 1968, MIT's AI Laboratory co-founder Marvin Minsky created a "tentacle arm" - a robotic 12-jointed arm that was powered by hydraulics and could be controlled via a joystick. Minsky's robotic tentacle was strong enough to lift a person, and could reach around obstacles easily. His research paved the way for many of the soft robotics innovations emerging today.
In 1969 Victor Scheinman created the Stanford Arm, a robotic arm that is considered to be one of the first robots to be controlled exclusively from a computer. This was a huge breakthrough, as at the time Unimate operated from a magnetic drum. It featured six points of articulation and was built entirely in Stanford's Artificial Intelligence Lab. Though used primarily for educational purposes, the Stanford Arm marked a major breakthrough for industrial machines that could be controlled via computers.
Source: Gildardo Sánchez/Flickr
The 1970s: The WABOT-1, Industrial Innovations, and Robots in Space
The early 1970s saw the unveiling of the world's first full-scale anthropomorphic robot - the WABOT-1. The WABOT-1 was a follow-up to 1967's WABOT, and was created by Ichiro Kato in Tokyo's Waseda University. The WABOT-1 had a vision and limb control system, allowing it to navigate itself and move freely. It could even measure distances between objects. Its hands featured tactile sensors, meaning it could grasp and transport objects. It had an estimated intelligence equal to that of an 18-month-old human, and marked a massive breakthrough in humanoid robotics.
The 1970s also saw the progression of industrial robotics when, in 1973, German company KUKA released the FAMULUS - the first industrial robot with six electromechanically driven axes. The following year, Richard Hohn developed the first industrial computer to be powered by a minicomputer - The Tomorrow Tool, or T3. In 1978 SCARA - the Selective Compliance Assembly Robotic Arm - was created. Developed by University of Yamanashi professor, Hiroshi Makino, the arm could move along 4 axis and became a common fixture in assembly lines in the early 1980s.
The first robots to land on Mars were Viking 1 and Viking 2, who landed on the red planet in 1976. Both robots were powered by radioisotope thermoelectric generators, which generated power from the heat given off by decaying plutonium. Though the data collected by both Vikings was ambiguous, they were the official forerunners of the Mars rovers we know today.
Source: Mark Pelligrino/Wikimedia Commons
The 1980s: Robots in the Home, the Canadarm, and Genghis
It was in the 1980s that robots officially entered the mainstream consumer market, though mostly as simple toys. One of the most popular of these robotic toys was the Omnibot 2000 by TOMY. The Omnibot 2000 was remote-controlled, and came complete with a tray for serving drinks and snacks. Another highly sought-after robotic toy from this period was Nintendo's R.O.B, or Robotic Operating Buddy. R.O.B. was marketed as a robotic player two for the Nintendo Entertainment System. It could respond to six different commands, which were communicated via light flashes from a CRT screen.
Source: Rama/Wikimedia Commons
The '80s saw further developments in the field of industrial robots, with Ford adding hundreds of robots to their assembly lines worldwide. The Ford Fiesta was notable for being one of the first cars in the world whose anti-corrosion sealants were injected by robots.
Robots continued their journeys through the cosmos in the '80s too, with the launch of the Canadarm on the Space Shuttle Columbia in 1981. The Canadian-made robotic arm was 50 feet (15.2 meters) long and had six points of articulation. It could be controlled by one crew member in the control station, and performed 90 successful missions during its time in service.
Often considered one of the most important robots in modern history, 1989's Genghis was a hexapodal robot made by researchers in MIT. Due to its small size and inexpensive materials, Genghis is credited with shortening production time and cost for future space robot designs. It was built with 12 servo motors and 22 sensors, and could traverse rocky terrain.
The 1990s: The Cyberknife, the Sojourner, and AIBO
The early 1990s saw robots enter the operation theater with the Cyberknife - a radiosurgery system that could surgically treat tumors. Developed by Stanford University neurology professor, John R. Adler, the Cyberknife was a non-invasive surgical tool which tracked and targeted tumors with narrowly-focused beams of radiation. By 2010, the Cyberknife was used in 5% of all Stanford Cancer Center's treatments.
In 1996 the Sojourner became the first rover to be sent to Mars. The small, lightweight robot was brought to Mars by the Pathfinder, and successfully touched down on the planet's surface in July 1997. During its time on Mars, Sojourner explored 2,691 square feet (250 square meters) of land and took 550 images. Because of the information gathered by Sojourner, scientists were able to determine that Mars once had a warm, wet climate. The mission marked the beginning of several more NASA rover missions to Mars.
Source: NASA/Wikimedia Commons
The late '90s saw the introduction of one of the most iconic robots of the 20th Century - Sony's AIBO robotic dog. Released in 1999, AIBO was one of the first robotic pets to hit the consumer market. AIBO could respond to voice commands and chase a pink ball which came with the purchase of the robot. Earlier this year Sony unveiled a new, revamped AIBO for the 21st Century market which came complete with two cameras and space-mapping capabilities.
Source: Sven Volkens/Wikimedia Commons
The 21st Century: The State of Robots Today
Though we're a mere 18 years into this century, robotics have already progressed and shaped so much of our technological landscape. Many homes now have their own Roombas - robotic vacuum cleaners that can clean your floors autonomously. We've seen the application of drones in everything from the military to home deliveries.
There have been so many landmark innovations in the past few years, that they would warrant their own article. When discussing the robotic achievements of recent years, however, it would be remiss not to mention two robots in particular - Sophia and the Boston Dynamics Dog.
Sophia made headlines last year when she became the first robot to be awarded citizenship to a nation. The Android robot, created by Hanson Robotics, was granted Saudi Arabian citizenship in October 2017. The following month, she became the first non-human to receive a United Nations title when she was named the UN Development Programme's Innovation Champion. Sophia's AI is cloud-based which allows for deep learning, and she can recognize and replicate a variety of human facial expressions.
Source: International Telecommunication Union/Wikimedia Commons
Boston Dynamics has been heralded in the media as leading the charge in modern robotics, thanks to their autonomous creations.
The most famous of these is the Boston Dynamics Dog, or BigDog, which captured worldwide attention upon its unveiling in 2005. It was designed to be a robotic beast of burden for military use, and featured 50 sensors over its body. It was capable of carrying weights of up to 340 lbs (150 kg) and could run at an impressive 4 mph (6.4 km/h).
Recently, Boston Dynamics revealed two more headline-grabbing robots - the MiniSpot and Atlas. MiniSpot is an autonomous robot dog that can open doors by itself, while Atlas is a sophisticated anthropomorphic robot capable of running and jumping over obstacles.
Source: Sgt. Sarah Anderson/Wikimedia Commons
If Boston Dynamics is any example to go by, robotic innovations are emerging on a near-weekly basis in this 21st Century. Robotics have enjoyed a long and storied history, and it would appear that we have far more to look forward to.
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Physical characteristics of the jaguar cat
Updated March 23, 2017
Jaguars are the third largest feline species in the world, ranking behind lions and tigers. The range of these big cats, who were worshipped in ancient times, extends from central Mexico to northern Argentina. Although they resemble leopards, jaguars have a few physical characteristics that distinguish them from their cousins in the Panthera genus.
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Jaguars are the biggest cats in the Americas. Adult males weigh an average of 54.4kg., although they can weigh as much as 136kg. Adult females typically weigh around 31.8kg. Jaguars measure between 3.8 and six feet in body length, with 18- to 30-inch tails. The larger jaguars inhabit open grasslands and plains in northern South America, while smaller ones roam the dense woodlands, swamps and rainforests of Central and South America, as well as desert regions in Mexico.
Unlike leopards in Africa and Asia, a jaguar's yellowish-brown or reddish-brown coat has a pattern of black rosettes with a spot in the centre and open, uneven edges. A leopard's rosettes form a complete, unbroken circle with no markings in the middle. The jaguar's coat pattern helps it remain hidden as it hunts for food. Jaguars that live in open habitats have paler rosettes than ones that inhabit forested areas. Jaguars have white muzzles and white fur on their bellies. Some jaguars that live in the deepest parts of the rainforests have black fur that shows a faint pattern of black rosettes. These cats are commonly called black panthers.
Jaguars have a broader build than most other big cats. They rely on strength rather than speed to bring down prey. Jaguars are able to hunt more than 85 different species of mammals, reptiles and amphibians due to their build and ability to swim. Their large heads have square jaws with powerful muscles and canines that can crush the skulls of animals such as caimans, tapirs, cattle and peccaries. They can also penetrate the thick shells of tortoises and turtles. Jaguars search for prey at night, since their vision is sharper in lower light. They stalk their prey, then use their stocky and muscular legs to pounce. They also hunt by twitching their long tails over water to lure fish to the surface.
Territorial Markings
Jaguars spend most of their lives alone and use a variety of methods to mark their territory. They use their claws, which stay retracted most of the time to prevent them from breaking, to leave scratches on trees or on the ground. They also vocalise through deep roars to announce their territory and to scare other jaguars or animals away from it. Urinating or defecating also serves as a way for jaguars to establish boundaries.
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History Stories
Archeologists in Italy have unearthed a 500-pound sandstone slab that may help them decipher the lost language and culture of a mysterious pre-Roman people.
Living in largely independent city-states that they laid out in a grid pattern, the Etruscans excelled at metalworking, seafaring, agriculture and pottery. According to the Roman historian Livy, “no people was ever more devoted to religious observances.” At the same time, they also loved to eat, drink, play music and dance—things “that we like to joke are still prevalent in Italian society,” said Gregory Warden, a classical archaeologist affiliated with both Southern Methodist University in Texas and Franklin University Switzerland. Such pleasures extended to Etruscan women, who enjoyed numerous freedoms denied to their Greek and Roman counterparts. On the darker side, Etruscan society was apparently sharply divided between rich aristocrats and their serfs and slaves. Moreover, human sacrifices appear to have been offered up to the demons of the underworld.
To this day, the origins of the Etruscans remain murky. Herodotus, the so-called “Father of History,” reported that a prolonged famine prompted the king of Lydia in present-day Turkey to send half his population to the Italian peninsula in search of a new home. However, Dionysius of Halicarnassus, another ancient Greek historian, believed the Etruscans to be native Italians, pointing out that they shared neither a language nor a religion with the Lydians. Recent genetic studies seem to support Herodotus’ claim, whereas archeologists have tended to agree with Dionysius, arguing that the Etruscans evolved from an Iron Age culture known as the Villanovans, with whom they shared many similarities. In fact, most Etruscan cities popped up right on the site of former Villanovan settlements. “What’s important,” Warden said, “is that the culture really is formed on Italian soil.”
(Credit: Mugello Valley Project)
(Credit: Mugello Valley Project)
Whatever its origins, archeological evidence shows that the Etruscan civilization jumped onto the scene by around 700 B.C. Reaching the apex of its power not long afterwards, Etruscan kings even controlled the city of Rome prior to being expelled in 509 B.C. upon the founding of the Roman Republic. A naval alliance with Carthage helped the Etruscans fend off a Greek advance around 535 B.C. But six decades later, a defeat at the hands of another Greek fleet precipitated the loss of the southern part of their empire. Meanwhile, Celtic tribes crossing the Alps took over much of their northern territory, and the increasingly powerful Romans began conquering one city-state after another. By the 3rd century B.C., all of Etruria had been subsumed into Rome, thus marking the beginning of the end for its distinct language and culture.
Though the Romans downplayed Etruscan influence, the Etruscans had a strong impact on their architecture, art, government and religion and therefore on Western civilization as a whole. In addition to inventing the toga and introducing winemaking to the French, the Etruscans even provided the model for the famous Roman alphabet (the standard script of English and many other modern languages). “The reason we go ‘A, B, C’ instead of ‘A, B, G’—which is what it would be in Greek, alpha, beta, gamma—is because the Etruscans didn’t have that G sound,” Warden said. Unfortunately, because they used perishable linen cloth and wax tablets for their writings, not a single Etruscan literary work survives to the present day. Of the roughly 13,000 known Etruscan texts, most are formulaic gravestone epitaphs that contain little more than names and titles. Linguists have therefore been unable to fully decipher the language, and historians have been forced to rely on the unflattering Roman and Greek accounts, which slander the Etruscans at every turn.
Inscriptions on the slate. (Credit: Mugello Valley Project)
Inscriptions on the slate. (Credit: Mugello Valley Project)
A new discovery may help the Etruscans to speak for themselves, if only just a little. On Tuesday, archeologists announced that they had uncovered a possibly sacred text embedded in the foundations of a temple at the Poggio Colla dig site, located about 20 miles northeast of Florence in the Italian region of Tuscany. Inscribed on a 500-pound sandstone slab that’s nearly four feet tall by more than two feet wide, this text was loaded onto a backhoe and carried to a lab in Florence to be cleaned, restored and mapped out. Despite being more than 2,500 years old, it contains at least 70 legible letters and punctuation marks, according to Warden, who co-directs the Poggio Colla excavations. “Long inscriptions are rare, especially one this long,” Warden said, though he pointed out it’s by no means the longest. That distinction, he said, belongs to an Etruscan prayer book made of linen cloth, which was remarkably cut into strips and used to wrap an Egyptian mummy.
Heavily abraded and chipped, with one reddened side that may have been burned in antiquity, the sandstone slab will be studied by, among others, Etruscan language expert Rex Wallace, a professor of classics at the University of Massachusetts Amherst. “We hope to make inroads into the Etruscan language,” Warden said. He added that, although “we know how Etruscan grammar works, what’s a verb, what’s an object, some of the words,” this rare non-funerary text will undoubtedly contain “a number of words that we’ve never seen before.” With any luck, he said, it will also reveal secrets about Etruscan religious practices and beliefs, including the identity of the god or goddess to whom the Poggio Colla temple was dedicated. “Apart from the famous seaside shrine at Pyrgi, with its inscribed gold plaques, very few Etruscan sanctuaries can be so conclusively identified,” Jean MacIntosh Turfa, an Etruscan scholar at the University of Pennsylvania Museum of Archaeology and Anthropology, said in a statement. “A study of the names of the dedicants will yield rich data on a powerful society where the nobility, commoners and even freed slaves could offer public vows and gifts.”
Other Etruscan artifacts discovered at Poggio Colla since it was first excavated in 1968 include gold jewelry, bronze statuettes and the earliest scene of childbirth in western European art.
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Testing Ion Thrusters For Space Exploration
Testing Ion Thrusters For Space Exploration
Somewhere in Princeton, New Jersey, a small team of physicists is hard at work making plasma in a lab. Plasma, a superheated gas that is ionized or electrically conductive, is already around us in many forms. Lightning and neon signs are examples of partially ionized plasma.
The center of the sun is fully ionized plasma. In the past two decades, plasma has entered the field of aerospace engineering through its use in ion thrusters. These small, plasma-powered engines are used on many modern satellites.
Plasma is made by subjecting a gas to a strong electromagnetic field. This causes electrons to begin breaking free of atoms, leading to the creation of positively charged particles known as ions. In an ion thruster, electric fields are used to push ions contained in a gas propellant out of the engine’s nozzle at high speed to create thrust.
Source: Aerospace Testing International
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Cloze test practice-16
PASSAGE 16 (Questions 1-5)
Directions: In the below given passage, there are blanks each of which has been numbered. Five words are suggested, one of which fits the blank appropriately. Find out the appropriate word in each case.
__(1)__ over the world, rights related to information technology are already legally recognised and daily being violated, __(2)__ in the name of economic advancement, political stability or for personal greed and interests. Violations of these rights have __(3)__ new problems in human social system,such as the digital divide, cyber crime, digital security and privacy concerns, all of which have __(4)__ people's lives either directly or indirectly. It is important that countries come up with the guidelines for action to __(5)__ the incidence of malicious attacks on the confidentiality, integrity and availability of electronic data and systems, computer related crimes, content-related offences and violations of intellectual property rights __(6)__, threats to critical infrastructure and national interests arising from the use of the internet for criminal and terrorist activities are of growing __(7)__ The harm incurred to businesses, governments and individuals in those countries in which the internet is used __(8)__ is gaining in __(9)__ and importance, while in other countries, cyber crime threatens the application of information and communication technology for government services, healthcare, trade and banking. As users start losing __(10)__ in online transactions and business, the opportunity costs may become substantial.
[IBPS (SO), 2012]
Select the appropriate word for blank 1.
Select the appropriate word for blank 2.
Select the appropriate word for blank 3.
Select the appropriate word for blank 4.
Select the appropriate word for blank 5.
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"url": "https://www.studyandscore.com/practice-test-exam/solved-cloze-test-question-answers-practice-test-16"
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Science Highlight March 2006
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20 years since the encounter of the Giotto space probe with comet Halley
Max Planck researches got spectacular results
20 years ago, on March 13 1986, the spacecraft Giotto encountered comet Halley. From the present point of view what were the most important results?
Comet Halley is a relatively bright comet. When it is close to the Earth and Sun it usually can be observed with naked eye. It looks like a star with tail. From a star-like condensation a tail grows, which, if seen at a dark place without interfering street illumination, can reach a considerable length. 1705 Edmont Halley predicted the periodic return of this object which now bears his name. The comet moves around the Sun on an elongated ellipse with a period of 76 years. It reaches its closest distance to the Sun at 0.587 Sun-Earth distances (88 Million km) and its largest distance at 35 Sun-Earth distances (5.25 Billion km) outside of the orbit of Neptune. Comet Halley shone the Normans, when they defeated the British in the battle at Hastings. Giotto di Bondone painted comet Halley as Christmas star on top of his painting of the birth of Christ in the Scrovegni Chapel in Padua. Already before the encounter of the Giotto space probe with comet Halley it was known that the phenomenon of a comet comes from a nucleus of the size of several kilometers: According to Whipple the nucleus is a dirty snowball, consisting of water ice, mixed with other volatile (evaporable) substances and solid materials (dust). They evaporate (better sublime) when they are heated by solar irradiation and form the neutral coma and the plasma tail. The dust tail consists of the dust particles dragged along by the evaporating gases.
Why we are interested in comets today? In important question for man is the question about his origin. This includes the question about the origin of the Earth and the solar system. As we know now, our Sun formed from an interstellar molecular cloud. In the molecular clouds there are gas and small solid bodies (dust). If the molecular cloud exceeds a minimum density, e.g. by freezing out ice at extremely low temperatures, it contracts and a central star is formed. At the same time, because of the conservation of the angular momentum of the cloud, a proto-planetary disk is generated around the star from which planets form. In this process it is important that both components, gas and dust, are available. The young star heats up by contraction. Nuclear reactions ignite in its interior, the same ones that supply our sun with luminosity and energy today. Like the Sun today, the early sun was hot and heated the inner parts of its proto-planetary disk more strongly than the outer ones. This caused chemical differentiation: easily evaporable material was lost close to the Sun and entered the inner planets only to a minor extent. In the outer solar system, however, volatile constituents like hydrogen were implemented into the planets. There is one more differentiation, namely according to the mass (weight) of the forming body. Small bodies (diameter smaller than 100 km) remain more pristine than larger ones that are able to contract like the young sun because of their gravity and in course of this are heated again. In this process the primordial chemical constitution and the distribution of matter in the body is altered further. A surprisingly detailed information on the chemical and mineralogical constitution of the inner solar system (Mercury to Mars) is obtained from the study of meteorites that enter the atmosphere as luminous meteors (shooting stars) and finally can be collected from the ground as chunks of cosmic stones or metal. But what about the outer solar system?
Let us now return again to the Giotto space probe, as the investigations of this probe (and of the Russian VeGa probes) have played a crucial role in answering this question.
1. The first images of the nucleus of a comet were obtained (under lead management of the Max-Planck-Institute for Solar System Research, which at that time still was called Max-Planck-Institute of Aeronomy). The cometary nucleus turned out to be an entity (no group of nuclei or even a "sandbank", i.e. an agglomeration of small and tiny dust grains) of size 16 x 8.2 x 7.5 km. This met existing expectations. Nevertheless it was a big step forward as for the first time an image of such a nucleus was available. Now it was clear beyond doubt that comets must be undifferentiated bodies, first because of their small size and second, because comets like comet Halley spend most of their time in the outer solar system, where the solar radiation is too small to heat them up sufficiently. That there are active areas on the nucleus of limited extent and that the inactive part of the nucleus is deep black, darker than coal, came as a surprise.
2. The relative mass fraction of dust in a comet was determined and the chemical constitution of the dust was measured. The latter experiment was construced under leadership of the Mx-Planck-Institute of Nuclear Physics in Heidelberg. The gaseous constituents of the cometary nucleus, which, by the way, can also be determined through observation of the characteristic molecular lines they emit, were measured systematically with mass spectrometers on Giotto. Dust and gas contribute about equally to the total mass (at least in comet Halley). The measured chemical constitution destroyed hopes that comets could be pristine relicts of the molecular cloud from which our solar system formed. Nevertheless comets contain significantly more volatile elements than the least differentiated meteorites (CI chondrites). The detection of large molecules as a link between gas and dust, similar to the aromatic hydrocarbons of the interstellar molecular clouds, was of particular interest.
Needless to say that every new result creates further questions. In case of the cometary nuclei there is the question about their inner structure and about the physical mechanisms causing the evaporation of cometary matter from spatially limited active regions. Concerning the chemical constitution the measurements must become more accurate and more detailed. Appropriate experiments exist on the Rosetta space probe presently on its way to comet Churyumov-Gerasimenko. It would be best if we could at some time investigate a piece of a comet in the laboratory in the way we do it already a long time with meteorites. Cometary dust from comet Wild 2, embedded in so-called astrogel, was returned to Earth by the American Stardust space probe early this year. But until we will be able to analyze a chunk of cometary snow or ice in a terrestrial laboratory we must still wait a while.
top Top Klaus Jockers, 22-03-2006 drucken Print−friendly Page
© 2009, Max Planck Institute for Solar System Research, Lindau Disclaimer
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What is hepatitis?
You can have hepatitis without any symptoms. In fact, the older you are, the more likely you are to have symptoms – making babies and children the least likely to show signs of the disease.
cartoon image of baby with thermometer in mouth
What is hepatitis A?
This form of the hepatitis virus is carried in stool and spreads easily from person to person. For example, your baby could contract hepatitis A by putting his hand in his mouth after touching something contaminated with the stool of someone who has the virus.
How would I know if my baby had hepatitis A?
In serious cases of infection, symptoms include fever, fatigue, loss of appetite, vomiting, abdominal discomfort, dark-colored urine, and jaundice. These symptoms usually last from two weeks to two months, though they can persist longer. Most babies infected with the virus show no signs of illness, though. If you believe your baby may have been exposed to the virus, talk to his doctor.
Is there any way to prevent hepatitis A infection?
Diligently washing your hands with soap and warm water – especially after using the toilet, changing diapers, and before preparing food – helps prevent the spread of the disease. Wash your baby's hands, too.
What happens if my baby's exposed to hepatitis A?
If you think your baby might have been exposed to hepatitis A (because a family member or friend has the illness, for example), he should get an injection of immune globulin (a.k.a. gamma globulin), which contains antibodies against the virus – preferably within seven days of exposure, but the sooner the better.
The protective effect of immune globulin lasts for several months. Your baby will still need to get the hepatitis A vaccine after he turns 1.
What is hepatitis B?
Ninety percent of babies under the age of 1 and 30 percent of children between the ages of 1 and 5 who are infected with hepatitis B develop chronic infections. By contrast, only 6 percent of infected adults develop the chronic form of the disease.
What are the symptoms of hepatitis B?
Most infected infants show no signs of illness, but symptoms of hepatitis B include fever, fatigue, vomiting, loss of appetite, and jaundice (yellowing of the skin and eyes).
If you had hepatitis B when you gave birth, your baby should have received both the hepatitis B vaccine and an injection of immune globulin, which contains antibodies against the virus. If that's the case, he should be tested when he's about 9 to 15 months old to make sure the vaccination was effective.
Can hepatitis B be prevented?
What is hepatitis C?
A baby can get hepatitis C from his infected mother, but it's uncommon. Hepatitis C is hard to diagnose in a baby, and there's no vaccine for it.
Show sources
AAP. Undated. Immunization: Hepatitis B. American Academy of Pediatrics. http://www.cispimmunize.org/aap/aap_main.html?http&&&www.cispimmunize.org/fam/hepb/fam_hep.html
CDC. 2006. Recommended childhood and adolescent immunization schedule — United States, 2006. Morbidity and Mortality Weekly Report 54(52):Q1-Q4.
Hepatitis Foundation International. Undated. Preventing hepatitis. http://www.hepfi.org/living/liv_preventing.html
Immunization Action Coalition. Undated. Hepatitis A, B, and C: Learn the differences. http://www.immunize.org/catg.d/p4075abc.htm
Mayo Clinic. Undated. Hepatitis A overview. http://www.mayoclinic.com/health/hepatitis-a/DS00397
Mayo Clinic. Undated. Hepatitis B overview. http://www.mayoclinic.com/health/hepatitis-b/DS00398
Mayo Clinic. Undated. Hepatitis C overview. http://www.mayoclinic.com/health/hepatitis-c/DS00097
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Understanding Altimeters
Understanding Altimeters
In its purest form, an altimeter is simply an absolute pressure gauge. This means that it is displaying the pressure being exerted by the atmosphere at its current location.
The earth is surrounded by an atmosphere. This atmosphere is the air that we breathe. The atmosphere is held in place by the earth’s gravity. The atmosphere has a specific weight. The weight of the atmosphere is approximately 14 pounds of weight for every square inch of earth when measured at sea level on an average day.
An accurate method of measuring this weight is to use a barometer. A barometer is a reservoir filled with mercury. The reservoir has two openings; one opening is exposed to the atmosphere and the other empties into a glass tube. The atmosphere pushes down on the mercury within the reservoir causing the mercury to fill up the glass tube. How far the mercury goes up into the glass tube is directly proportional to the weight of the atmosphere pushing it. This is why barometric pressure is normally expressed in terms of “Inches of Mercury (InHg)”.
At sea level, on an average day, the barometric pressure is 29.92 InHg. However, this will vary constantly depending on the weather. Stormy weather tends to pull the atmosphere away from the earth’s surface causing lower pressure. Hot, dry weather pushes the atmosphere down causing higher pressure.
The weight of the atmosphere also changes depending on altitude. The closer to sea level that you are, the more air there will be, consequently the atmosphere will weigh more. As you go higher in altitude, the less dense the atmosphere will be, therefore less weight or pressure is exerted. An altimeter measures this change in atmospheric weight as expressed in terms of pressure or feet of altitude.
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Human biology short notes
Extracts from this document...
Name of organelle Structure Function Cell membrane Composed of mainly proteins and lipids Forms the outer boundary of the cell Partially permeable (Selective)- has special pores Controls the transfer of substances into and out of the cell Prevents cell contents from escaping or mixing with the neighboring cells medium Cytoplasm Structure less, semi- fluid, jelly like substance Provides a medium for chemical reactions Suspends organelles within the cell Nucleus Spherical body Contains a nucleolus Neucleoplasm suspends chromatin Nuclear membrane contain special pores Controls cellular activities Contains chromosomes responsible for cell division Plastids *Chloroplast (Only in Plant Cells) Colourless plastids contain starch (used as a food store) Plastids which contain a green pigment- chlorophyll are called chloroplast Chlorophyll present absorbs the energy from the sunlight and uses it for photosynthesis in plants Cell wall (Only in Plant Cells) Made up of mainly cellulose Forms the outer boundary of the plant cell Not selective Non-living Keeps the rigid structure of the cell Since it is not selective allows any dissolved substances to pass through Mitochondria Doubled membrane- inner membrane is highly folded to increase the surface area Responsible for generating energy for cellular activities Aerobic respiration takes place inside Produce a short term source of energy -ATP Endoplasmic Reticulum (ER) Forms a network of inter connected membranes within the cytoplasm *Rough ER-have ribosomes *Smooth ER- do not have ribosomes attached to their membrane Carries commands from the nucleus to different parts of the cell Helps in the movement of substances within the cell Plays an important role in protein synthesis Ribosomes Produced by the nucleolus Contains two ribosomal units (big one and a small one) Some are attached to ER forming Rough ER Responsible for protein synthesis Receives RNA commands from the nucleus to make proteins Gogli apparatus Elongated sacs Near site to the nucleus Gathers and assembles substances for making cellular structures (Example: cell membrane) ...read more.
Location of Cell Body- Situated in the Grey Matter of the CNS Synapse * Synapse is the gap between two neurones * Electrical impulse arrives at the end of the neurone * Stimulates the release of neurotransmitter substance (chemical) * Chemical crosses the gap to the second neurone by diffusion * Enzyme is released to destroy the chemical in the synapse Reflex Action * Reflex action is a rapid involuntary response to a stimulus * Does not involve the Brain * Has a protective function Reflex Arc Is the nervous path way provided for a reflex action Advantages of Reflex Action * Sharp object/heat causes limb to be pulled away * Automatic response * No thought involved * Brain does not receive impulse of action * Prevents skin from further damage Spinal Cord * Spinal cord is the main part of the CNS which is involved with reflex actions * Spinal cord is divides into two main roots o Dorsal Root- Sensory Neurones enter the spinal cord o Ventral Root- Motor Neurones leave the spinal cord * Most cell bodies are concentrated in the Grey Matter * Most nerve fibres are concentrated in the White Matter The Brain * The Brain expanded part of the spinal cord * Parts of the brain and their functions o Medulla-controls involuntary actions such as breathing and heart rate o Cerebellum- Maintains the balance of the body o Cerebrum- Deals with acquired skills, memory, intelligence, consciousness, reasoning ability * The cerebrum consists of two cerebral hemispheres which act as the main command centre of the body o Hypothalamus-has receptors which detects changes in the blood as it flows through the brain When the head is jerked backwards violently * A break occurs in the spinal cord * The nerve path way between the brain and the body is severed * No feeling below the break * And the brain no longer has control of muscles below the break Endocrine System * The Endocrine system depends on the action ...read more.
Sprinkler/Trickling filter/Pre Colating * Liquid drips on pebbles (clinker) * Oxygen collects and airates the tank * Pebbles are coated with slime from bacteria and other microbes which are anaerobic * They feed organic materials in sewage * As a result heat is produced which kills pathogens in liquid effluent and makes it safe Purification of Water 1. Grids/strainer remove large objects 2. Water is sent at slow rate through the inlet 3. Slow Sand Filter * Bacteria fungi and other microorganisms reproduce and a jelly which is supported by the sand * A food chain forms and the microorganisms in the water competes with the bacteria from the jelly as the water passes OR 3. Rapid Sand Filter * Alum is added to coagulate as it forms a thin jelly which traps various kinds of particles * The water and the jelly are passed under pressure through large tank * The sand supports the jelly while the water passes rapidly through Chlorination * When bubbled through water forms a weak acid * Which inhibits the growth of microorganisms * And kills microorganisms already present * Water is then kept in large enclosed reservoirs so that no more organisms can enter * Delivered via closed pipes to taps Pit Latrine * Pit must be dug to allow build up during decay * The pit is lined with concrete to prevents seepage and entry by burrowing animals (Example: - Rats) * The floor is made out of concrete this allows hygienic cleaning * Cover for the pit, the cover prevents flies from landing on sewage and prevents smell from escaping * Mesh cover the pit to prevent files from entering to reduce the spread of pathogens Why it is important to consider the location of a pit latrine ? The pit latrine must be situated away from uphill water supply and sited away from houses To reduce flies and other vectors transporting pathogens which might cause diseases to the house Must be built at a distance from the house due to the bad smell ?? ?? ?? ?? Page 1 ...read more.
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On the other hand if there is a lot of water in the blood, for example after having a drink, the receptors in the blood will not be stimulated as much, less ADH will be produced, less water will be reabsorbed into the blood and more will pass into the urine.
One problem is that ethanol is poisonous in large amounts. If the concentration of ethanol gets more than 14% it kills the yeast and respiration stops. Thus, if the experiment was carried out in anaerobic conditions the experiment couldn't be carried out for too long.
The major function of the capillaries is to promote exchange of nutrients and metabolic end products between the blood and the interstitial tissues. Such exchanges are facilitated by the presence of specialized junctions, gaps or fenestrations, which increase surface area.
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Beaver with mid ear infection
Late February 2018 the Dutch Wildlife Health Center (DWHC) was contacted about a beaver (Castor fiber) that displayed very abnormal behavior before it was euthanized in the field. The beaver did not respond to people and appeared blind and deaf. The person who discovered the animal had given the beaver a little push to see how it responded; the beaver had trouble getting back to its feet and appeared to have trouble with its balance. The Stichting Faunabeheer Flevoland (organization coordinating issues relating to wildlife / game in the province of Flevoland) heard about the case through operators of the ‘dierenambulance’ (an emergency vehicle outfitted for animal rescue). One of the employees of the Stichting visited the site and saw the animal swim. After the beaver climbed on shore, he approached the animal within a few centimeters while recording its actions. After consultation with a DWHC veterinarian the animal was euthanized due to its abnormal behavior and the animal was submitted to DWHC to investigate the cause of the odd behavior.
The beaver was an adult male, but only weight 15-16 kilograms (normally this is ~20kg) and had no fat reserves. The examination of the animal revealed that it had a chronic mid ear infection of its left ear. The infection was severe and would not have resolved naturally. It is not possible to determine how long the animal had the infection. However, it was clear that the ear infection had been going on for a while because the adjacent nerves and bone were also damaged. These observations explain the abnormal behavior of the beaver: approachable, incoordination, deaf and blind appearance. An ear infection of this severity is most likely very painful, just as it would be for us humans, which bothered the beaver. As a consequence of the ear infection the beaver had mild iron accumulation in the liver that led to inflammation of the liver.
histologisch beeld oorontsteking bever
Macroscopic image of the ear infection (arrows) Histological images of the ear infection (arrows)
Bever staart met verwonding
Old wounds on the tail of the beaver
There were old wounds in the beaver’s tail. These wounds were most likely acquired during fights with other beavers. Beavers defend their territory and deep bite wounds can occur during this process.
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"url": "https://www.dwhc.nl/en/beaver-with-mid-ear-infection/"
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Migratory Birds
Migratory Birds 512x219
Felsenthal National Wildlife Refuge lies within the Mississippi Flyway—the "highway in the sky" from nesting grounds to wintering areas through middle North America used by vast numbers of migrating waterfowl, shorebirds, neotropical songbirds, and birds of prey. Almost 100 species of birds are known to nest in the area, and over 200 species have been sighted on the refuge.
Waterfowl usually begin arriving to the refuge in September, including mallards, green-winged teal, shovellers, pintails, gadwalls, blue-winged teal, and hooded mergansers. In some years, over 100,000 to 300,000 waterfowl have been found within the Felsenthal NWR.
During the spring, summer and through early fall, Felsenthal becomes a haven for a variety of songbirds and shorebirds. These birds stop briefly in the fall and spring to replenish energy reserves for the long journey to and from wintering areas in Central and South America. Other birds, such as Northern parula, prothonotary warbler and American redstart utilize the refuges for nesting.
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Have we found the key to eradicating viruses like HIV or herpes?
By Michael le Page Every human has viruses lying low within them. It’s highly likely that you have been infected with a human papillomavirus at some point, for example. HPV inserts copies of its DNA into the genome of cells, allowing it to hide away for decades, ready to activate and infect more cells if your immune system slips up. The consequences can be lethal: HPV can cause neck, throat, anal and cervical cancer. The herpes simplex virus does a similar thing, adding one or more copies of its DNA to sensory nerve cells around the mouth or genitals. And several other common viruses also exploit this dastardly trick to hide away within you. Until recently, the best we could do was help the immune system suppress any viral activity. With the development of the first gene-editing tools, researchers began to explore the possibility of destroying the viral DNA inside our cells, but progress has been slow and results mixed. Now, with CRISPR, the field is racing ahead. Several groups have shown that it is possible to target and destroy viral genes in human cells growing outside the body. “We are all brimming with excitement,” says Bryan Cullen of Duke University, whose team is working on treatments for several viruses, including herpes. “There will be a huge demand if a cure is possible.” It should be easiest to target viruses that integrate themselves into specific tissues in a small area of the body, such as herpes simplex. Could it also work for HIV? The problem, Cullen says, is that HIV hides in memory T-cells,
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What is Port Forwarding ??
port forwarding
The Port Forwarding is the method to transfer a forwarding network port from one particular system to another system. This method is usually applied when the in receipt of system is behind a private and public network modem. It is enables customers from outside the local area network (LAN) to reach private customers in the local area network itself. Now each system on the internet has at least one internet protocol (IP) address, which is used to recognize that particular system service. Each internet protocol address is separated into various network ports. The network ports are there for the system to communicate with every other, as well as therefore transferring the port will also improve the speed of the transmission between the two systems.
A look at how the systems are linked to the internet when behind a modem. The modem is primary linked to the internet, which we will call it outside internet protocol. The modem will then have it is own internet protocol address. The modem will then allocate an individual internet protocol address to each system that is linked to the private network modem. The modem internet protocol address will then act as a entry for all the systems that are on it is network. When a particular system in the internet network wants to transfer data and important information out to another system in the internet, it will primary pass it from side to side from the previous entry to the modem so that it transfers it out to the recipient.
The receiver nevertheless, will not be able to tell who in the internet is transferring him the information as the internet will only show the exterior internet protocol address here. It is when another system exterior the network is transferring information to a receiver inside the network, the data communication will be transmitted to the exterior internet protocol address and not directly to the intended recipient. The modem will then decide, which recipient should take delivery of the information that is being transmitted. This is where deport forwarding comes into location. This easy procedure is just a way for customers to tell the modem, which system in the local area internet protocol network is the intended recipient and that the information should be directed to him. You will required to set up port forwarding rules and regulation for each port, which you are using and any rules set up for a certain port will only work for that sure port.
One most useful true factor to note is that a port can only be used by a system program at any one time. For example, when system X is using port 5000, it is using port 5000 on its internal internet protocol address. If you have set up a port forwarding rule for system X and port 5000, the outside internet protocol address’s port 5000 is also in use. This means that you can only use port 5000 on one system on the network at a one time. Using port 5000 on two systems at the similar time would violate the one program rule, and the data would get disturbed.
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Ancient Greek Civilization
The seed for the great civilization of Greece was laid down almost 40,000 years ago. These very first inhabitants were mostly hunters and gatherers using well-crafted tools and weapons. The very first settlement began with the cultivation of cereals and plants, domestication of animals and weaving of clothes in looms. Small villages sprang along the farmlands which later developed to polis or city states.
Another major technological innovation was the use of bronze and other materials that further distinguished them from other cultures. With this, the economy expanded and the settlements grew larger along with wealth, power, and authority. This stage also marked the growth of leaders in the society.
The setting of the civilization
The cradle of Greek Civilization that influenced many other western civilizations was in a large peninsula that was surrounded on three sides by the Mediterranean Sea. Many smaller islands in the Aegean Sea also were under the Greek Civilization. These islands were the Cyclades, the Dodecanese, the Ionian Islands, and the Isle of Crete along with southern peninsula of Peloponnese. Other than these main islands, Greece also included thousands of smaller islands.
A major portion of the Greece was also constituted by the mountains and there were rugged landscapes between the Mountains and the sea. Along with the distance, lack of large rivers made transportation a challenge which made it impossible to unite the entire Greek under one ruler.
Only about 30 percent of the land was classifiable as cultivable, in which 20 percent were classified as good agriculture land. The Greeks colonized a number of villages to meet their agriculture requirement.
The best way for travel and trade was the sea routes. Many of the islands in the Aegean Sea facilitated these voyages. Locations that offered good harbor developed as ports. Trade was an important means for all raw materials except building stone and clay.
The beginning of the Greek Culture
Mesopotamia which the Greeks named as the land between the two rivers marked the beginning of an advanced civilization. It had large-scale irrigation, large cities, bureaucratic government, and trade networks. On the other hand, Egyptian civilization along the river Nile was a united kingdom ruled by a single leader, the Pharaoh. In Mesopotamia, however, societies evolved around great cities which took over surrounding towns and villages to become a single political unit. With time, powerful political unit conquered the weaker ones. The society had clear class distinctions and leader deployed a huge amount of labor, surplus wealth to build massive walls, temples, luxurious palaces, and tombs. These civilizations had an enormous impact on the cultural development of Greeks.
The Cretans also influence the Southern and Western Greece through trading contacts which became a base for the development of the Mycenaean Greek Civilization. The Greeks adopted the Cretan State including the writing system. The Greeks, however, invaded them and the civilization came crashing down.
The Greece and the Aegean
Trading contacts influenced the Southern and Central Greece by the Cretans. This relationship played an important role in the development of the early Mycenaean Greek Civilization. The Greeks borrowed almost everything from the Minoan culture right to the writing system.
Around the Middle Bronze Age, the population rose, productivity increased and trade further expanded in the mainland Greece which helped in further strengthening of the economic and political power of the leaders. Warriors evolved into monarchs. The settlements of Mycenae, Pylos, Thebes and Athens are believed to be major cities of this time.
During the fourteenth and thirteenth century, a number of palace complexes were built that was also considered the final phase of Mycenaean wealth and power. The architecture and decoration of this period could see a close linkage to the Minoan style. These palaces, unlike the unfortified Cretan palaces, were located on hills or higher mounds protected by thick walls. Although there was a lot of cultural similarities, the Mycenaean were not united and were divided into a number of smaller kingdoms. However, in spite of their highly divided political background, they were a strong presence in the Mediterranean world.
The palace was the center of the kingdom’s economy, employed a large number of workers to produce finished goods for domestic use as well as export. Major exports included textiles and metal-works.
The Minoans and the Mycenaean believed in supernatural forces. They paid respect to their gods with processions, music and sacrificing of animals. The palace also acted as the center of religious activities. The priest and priestesses who were considered as the direct connection to the gods were gifted with lands, animals, precious objects etc.
Many of its palace complexes, towns and villages were either attacked or abandoned. Not only Mycenae, the entire Mediterranean area suffered many catastrophes during this time. The end of this stage marked the beginning of a new era which was very different to the earlier civilization.
With the end of this civilization, Greece entered what is commonly known as the Dark Ages. Many cities disappeared, the population decreased and communications ended leading to failure in trade and travel as well.
The Dark Ages and revival of Greece
The elaborate socio-political structure collapsed with no kings, officials, scribes, palace staff and armies. There was no progress in architecture, art or even in furniture which was a common sight in the earlier period. Towns and villages were abandoned. Some areas suffered a longer stagnation period while areas around the Aegean Sea suffered a lesser period of decline. Most major centers including Athens continued to survive through the dark ages without much disturbance and other cities which suffered abandonment were reoccupied in a generation or two.
Life continued in Greece much like before however in simpler ways. One of the most important aspects of the revival of Greece was important technological innovations like a faster potter’s wheel that improved the shape of the vases. Superior potteries were produced that were elaborately decorated. There were vast improvements in metal works too.
Around 1050, there was increased movement from Greek mainland across the Aegean Sea to the Anatolian coast. Numerous settlements emerged such as the Miletus, Ephesus, and Colophon that grew to major urban centers. This also created a large presence in the East, colonizing the Aegean Sea as Greek Sea. While in the mainland, Athens and Corinth were growing as major centers too.
Around 8th century also called as the “Greek Renaissance” was a period of population growth, technological innovations and increase in political structuring. This phase was also considered as the revival of the glorious time of Mycenaean Period. There were tremendous growths in trade and communications with the East. Neighboring and isolated regions met frequently to celebrate festivals and take part in rituals along with athletic events.
The beginning of the regime of land ownership
The growth of population put an additional pressure on land. The elite class owned most of the land. These lands were mostly lush green meadows which were slowly converted to farms to grow grain and other crops. The elite class established themselves into an aristocracy of landowners. With the scarcity of land and ownership of land concentrated to a few, Greece was entering into a point of saturation.
Establishing new colonies for new farmlands became the new answer to the current problem of land. The second half of the Eight Century saw an increase in the number of colonies in southern Italy and Sicily. During this time, there were also tremendous growths in trade and commerce. Large numbers of Greek ships were plying across the Mediterranean resulting into a rise in many Greek Colonies in the west too.
The increase in the number of colonies and trade boost the economy of Greece. There was a tremendous increase in the work of craftsmen, sailors, shipbuilders etc. Farmers too took advantage in the growth of the economy and started trading their surplus production. The elite landowners were the most benefited from the lot as they could produce large surplus owing to its vast ownership of land.
With the increase in networking, there were significant influences on the culture especially in the alphabet and the writing system. The Greeks took its inspiration mostly from the Phoenician alphabet. They made modifications to their own language and with adaptations from other cultures came up with their own writings and language. However, information is believed to have passed on from mouth to ear even during the Classical and Hellenistic Period.
Another significant improvement was art and architecture. Major changes were seen in the art depiction on pottery. Greek temples, the signature architecture form also emerged during this time. The elites found a way to flaunt their richness in the form of architecture.
The Archaic Greece: Greek city-state establishment
This period in the history of Greece is marked with frequent wars with warfare becoming more lethal. While leaders fought to rise among themselves, poor citizens fought for economic stability and their civic rights. This gave rise to a new social and political framework popularly known as the city-state.
On the other hand, the population continued to rise resulting in the founding of more colonies spreading through the Mediterranean and the Black Sea. Trading increased manifold. On the cultural front, the Greek established a common identity. A number of shrines, festivals oracle grew along with new forms of literature, art, and expressions.
However, the most important phase of this period was the city-state. A city-state is a geographical area comprising of a central city and the territory around it. It is governed by a single political unit. The central city or the capital city was the focal point of the state. People of a higher class or the elite lived in the capital city while people of the lower social order lived outside the city. One could see cases of regional unification of several city-states lying in close proximity to each other.
The leaders of the city-states became the planners and the architects of the newly emerging city-states. A complex system and organization of social order were developed to respond to the changing structure of the society. The main aim of this organization was to mobilize men and resources for warfare as there were constant wars among polis with rising power. These leaders of the city-state also ensured that they preserve their economic and political power. Each city-state developed their own system of magistrates based on their needs, circumstances and the size of the polis. However, the main power remained in the hands of the council of elders.
As the economic power rested in the hands of the few land owning aristocrats, they became even richer as they had a greater share of land. They were also known to exploit the poorer section of the society. The social order during this phase could be divided into three categories: the elite few, middle class and poor. Even though all free-born members of the polis were citizens, there were no equal rights other than in religious worship. Women were denied of any participation in public affairs. The end of the archaic period saw a civil movement for full participation by all citizens in the governance of their polis. The main struggle was for re-establishment of land ownership. By the early sixth century, the position of the ruling members weakened and an inclusive form of government was taking shape.
Architecture excelled during this period and was centered on religious structures, temples, monuments, and treasuries which were mostly dedicated to the gods. The sixth century also saw the addition of large stone temples which was an inspiration from Egyptian techniques. Capital cities became major urban centers with the addition of all these monumental temples. A number of free-standing sculptures came up which was clearly another inspiration from Egyptian culture. Another major advancement in this period was the monumental architecture where marble and limestone replaced mud and brick construction. The concept of Agora which became the urban center of many activities solidified during this time with the building of monumental temples and public buildings around it. Agora also became an active marketplace and a public space. It was also a place where male citizens congregated for various activities and discussions. During the sixth century, there was also a rise in Greek Philosophy. Pythagoras is one of the most influential cosmologists which are known for its geometric theorem.
Greek even though was politically divided was culturally united. Most gatherings happened in PanHellenic sanctuaries and a number of people came for worship, consult oracles and attend other functions and athletic competition. The sanctuary of the Zeus was the greatest attraction at Olympia. Athletic games were organized in the honor of Zeus which later became Olympics.
The co-existence of city-states became critical with raids turning into major warfare. With the growth of population, land became scarce and the attempt for extending their boundaries gave rise to conflicts. Such interstate tensions were especially more in the Greek city states of Sparta, Argos, and Corinth. In the sixth century, Greek city-states realized the need to come to a conclusion to formally avoid wars. Cooperative institutions were regularized in the Archaic Period. Leaders made foreign policy for peaceful existence either through marriage alliances or pacts of political friendships. There was existence of Military alliance which became more long lasting during this time.
The Sparta
Sparta considered the most powerful city in the Greek world was constituted of the city of Sparta as the city center and the surrounding territories. Spartans were known to be hardcore patriotic with a lot of pride in their city-state. Spartans were also known for its selflessness and their unified image. Sparta being located inland and far from the port encouraged the city to tackle the issue of land crisis due to rising population. The Spartans did not establish colonies except for one but conquered its surrounding territory. The conquering of the surrounding areas especially Laconia and Messenia made Sparta one of the largest and the richest Greek city states. It was also famous for its pottery and metal works.
The Spartans put a special emphasis on education and upbringing of boys. Every man was expected to be skilled in warfare and give up his life for the city. Every Spartan was liable for military service till the age of sixty. Every man was trained for only military service and no other profession. Male infants were examined by officials and decided whether to be raised or abandoned. All children received education under state supervision. Spartans were the only society in Greek where women’s upbringing was prescribed by the state and were educated by the state at its expense.
The government was divided between two rulers. These two rulers or kings were both competitive and cooperative with one another. They exercised military, religious and judicial powers. One king took care of the military services while the other took care of the domestic affairs. Sparta also had an assembly which was highly democratic. Spartans was respected far and wide for its government which consisted of monarchical, oligarchical and democratic elements.
The growth of Athens and the rise of Persia
Athens which was a cluster of villages around the Acropolis, new settlements appeared around it with a sharp rise in population around eight century. There were cases of internal colonization but Athens hardly colonized overseas. The early government of Athens was aristocratic. However, during the latter part of the eighth century three civic officials who divided the duties equally among themselves. At a later stage, six judicial officers were added making a governing body of nine members. These nine members were elected annually from aristocratic families. Leaders such as Solon strengthen the weak agricultural system of the economy of Athens so it could raise enough grain to meet the demands of the growing population. While on the other hand, Peisistratus key focus was to strengthen the economy. Like Solon, he focused on growing both agriculture as well as commerce. He encouraged cultivation of olive and gave land for a loan to the needy. The trade in Athens improved greatly during his leadership. Peisistratus building projects gave employment to the poor people of the Athens while building it as the cultural center.
The Persians were among the many Indo-European people that were settled in Iran in first millennium BC. The Medes built the first Iranian empire by overthrowing the Assyrian Empire. The conquest of Greeks of Asia Minor by Cyrus II led to the re-definition of the course of Greek History. Cyrus was acclaimed as a talented ruler who supported local cultures and religions. After Cyrus, it was the reorganization of the empire by Darius I that ensured the long-term survival of the empire.
The political scenario changed in Athens after the Battle of Marathon which was fought between the Greeks and the Persian. Strategic council was selected to cater to the need for capable military commanders. In the spring of around 479, the Greeks fleet pursued the Persians navy at the Battle of Mycale finally ending the Persian threat to Greece Forever.
The Growth of Athenian Democracy
In order to prevent another invasion, a number of Greek city-states entered into a military alliance led by Athens. It was the Athenians naval strength due to which the Greeks won the war. The dependence on the lower class citizens that was part of the naval fleet became increasing pivotal to city’s security and well-being reducing the monopoly of the elite aristocrat. Democratic reforms hence took place to remove or undermined the wealthy that enjoyed control over Greece. However, there was no change in the status of women or slaves. Indeed with the rise of Imperialism, there was growth in the number of bonded slaves and the status of women decreased more with the rise in democracy among male members. Athens became a major cultural hub and tourists from all over Greece arrived to be part of cultural events and theatricals. Olympia, on the other hand, remained a religious center. Democracy similar of Athens developed in many places in Greece and many intellectuals were bringing in new ideas to birth. The Culture of Greece continued to flourish under the reign of Alexander the Great and influenced many medieval civilizations and the culture of Western Europe and the Americas.
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At the end of this module, the learners should be able to :
- Differentiate count nouns and non-count nouns
- Identify what article to use
- Construct sentences using the correct articles
What is a Noun?
What are Count Nouns?
Nouns that can be counted
two pens, a dozen apples, 30 attendees
Singular or Plural
Bottle/bottles, cat/cats, child/children
SVA rule applies
The employee drives to work every day.
The employees drive to work every day.
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What is a quadratic equation?
A quadratic equation is an equation of the form:
where equation, equation and equation are coefficients. This is a polynomial of second degree. Solving the equation means to find all values of equation such that the left hand side equals some value equation which often is zero.
Solving quadratic equations
Quadratic equations can be solved in different ways:
• Quadratic formula
• Factoring
• Completing the square
In the following we explain these different ways and demonstrate them with the following example which we want to solve:
Quadratic formula
The quadratic formula can be used to solve any quadratic equation. The formula is as follows:
The equation sign denotes that there are two solutions equation and equation where one of them is the above equation with a plus and the other one with a minus.
In our example, our coefficients are:
(1) equation
Now we substitute them into the quadratic formula and solve it:
(2) equation
We found two solutions. Both equation and equation solve our example equation.
Some equations can be easily solved by factoring such as our example. Let us factor the equation (first we divide it by 2):
(3) equation
We can see now that the left hand side will be zero when either equation or equation. We can easily solve these equations to find the two solutions for equation which are equation for the left term and equation for the right one.
Completing the square
For a quadratic equation where we can’t easily use factoring, we can complete the square so that it becomes a square trinomial. Let us look at our example and how we need to transform it to make the left hand side a square trinomial. We first bring equation to the right hand side so that we only have terms with equation on the left side:
(4) equation
To make the left hand side a square trinomial we must add equation to it. In this case equation=3, so we add equation to both sides and factor the left side:
(5) equation
Next, we solve the equation by taking the square root and solving for equation:
(6) equation
We found the same solutions for equation which are equation and equation as we found with the other ways. You can use any of the three presented ways to solve a quadratic equation. Of course you should know all of them in case your teacher asks you to use a specific way. But you might have a preferred way that you personally find the easiest and you can also use it to confirm your solution that you found with any of the other ways.
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Sedimentary Rock
Sedimentary Rock covers 75% of the Earth, but makes up only 5% of the crust.
Since sedimentary rock covers so much of the surface of the Earth, most of us will encounter it almost on a daily basis. There was a time when people saw all the various rocks, but they were not interested in how they were made or how old they were. Those that did have an interest in rocks did not always use proper scientific methods to understand them.
The last great teacher of the old fashion geology was Abraham Werner. Werner believed that physical features such as mountains and valley were formed by sudden spectacular events called Catastrophes. During Werner's time, no one tried to explain how land forms came about — except to say that mysterious forces within the Earth produces them.
A few people began to doubt Werner's teachings. One of these was a Scottish physician and farmer by the name of James Hutton. Hutton observed the action of streams that ran through valleys and saw that running water moved dirt and pebbles down stream. He believed rivers cut into the rocks of the hills and made valleys.
Hutton stated, "The Present Is The Key To The Past.""
Observe what geologic processes are happening today: they are the same ones that occurred in past years. This is known as the Principle of Uniformitarianism.
There are 3 sources of Sedimentary Rocks
1. Clastics: made up of fragments from other rocks.
2. Chemical: grains formed from evaporation, precipitation. or a chemical reaction.
3. Organic: formed from the remains of plants and animals.
Clastic grains are broken off other rocks and then transported to a new environment. The transporting agent can be:
I think that we all have seen wind blowing dust or a muddy stream or river. Fragments of rock are being transported. If the water is flowing fast enough, larger fragments like sand and gravel are transported. In a desert we have large sand storms transporting the fragments of rock. But some of us might not be sure how gravity transports rock. You might see a landslide along a highway or a large rock coming down the side of a hill or mountain. What made them come down -- gravity.
Most of the rocks that are transported are not large rocks but smaller fragments that broke off the bigger rocks. How did the fragments break off the larger rock?
We will look at the factors that determine how these fragments are made.
Conglomerate: gravel-sized grains
Sandstone: made of sand
Shale with fossils
Shale with Fossils: made of fine grains
Factors that determine how fast rocks weather:
1. Kind of Rock
2. Climate
3. Cracks in the rock
The rocks that make fragments are the rocks that are exposed to weather. Some rocks can withstand the weather better than others. So we must consider the rock type. Granite for example is extremely hard. You can beat on it with a hammer and find it difficult to break off a piece. But on the other hand, doing the same thing to sandstone will give you lots of little pieces. This is why we use granite for tombstones -- it does not weather fast.
The fragments are held together by a cementing agent. This cementing agent is usually the mineral quartz or calcite. Calcite is easily dissolved by acid. In nature it is a mild acid called carbonic acid (rain).
Climate has a lot to do with how fast a rock weathers. If the weather conditions don't change, the rock is less likely to weather fast. If the climate is rainy, rocks will weather faster. If the climate is season, weathering is also faster.
Cracks in rocks permit water to get into the rock. If the temperature goes down to freezing at night, the water will freeze. Freezing water expands. This is like driving a wedge into the rock. If this happens night after night, the rock will break. This is how potholes in the roads are made.
Nonclastics are formed by chemical and organic processes.
Evaporates are formed by the evaporation of water
Example: halite (salt), gypsum (the white stuff in drywall)
Under lake Erie there is a hugh deposit of salt from a previous lake that evaporated.
Rocks will decompose; this happens mostly in tropical areas
Rain + CO₂ → Carbonic Acid (H₂O₃)
When rain mixes with carbon dioxide in the atmosphere, it makes a weak acid called carbonic acid. All rain is a mild acid. This should not be confused with what we call Acid Rain (which is a stronger acid).
Carbonic acid will decay rocks: Granite changes to Clay
Limestone is mainly composed of the dead remains of sea creatures. The bones of fish and shells from mollusks are the main ingredients.
Peat → Lignite → Bituminous Coal → Anthracite Coal
Coal starts out as trees and ferns in swamps. When they die, they are covered by water. They don't decay the normal way. No insects to help out. As more and more pile up the material is compressed. The material is all organic. Made up of carbon, hydrogen and oxygen. The first step in the formation of coal is Peat. When this is compressed more it forms Lignite. This material is now mainly carbon and hydrogen. It will burn but does not produce must heat. Under further pressure the Lignite is Changed to Bituminous coal. This is the first true coal. It burns much better than pollutant. When the sulfur combines with rain water it forms sulfuric acid. This is what we call Acid Rain. If the bituminous coal undergoes more pressure and is baked from the heat from magma, it changes into Anthracite Coal. This is a clean burning coal with lots of heat and very little air pollution. It is found in mountainous regions.
Anthracite coal
Anthracite Coal
Special Sedimentary Features
Strata: This what each different layer of rock is called.
Bedding Planes: the division which separates the individual layers (strata)
Ripple Marks: Found in bedding planes; marks left in the sand or mud by wind or water (waves).
Geodes: Round cavities lined with crystals of quartz or calcite.
Fossils: any record of past life; most abundant in limestone.
Fish Fossil
Fossils 2
Nautilus Fossil
Sorting is separating. It's like sorting the laundry. Putting different colors into different piles. Flowing water will do the same thing. When the water is flowing fast, it carries all sizes of rock fragments. But when the water slows, it can not carry the heavier rocks. So they are dropped or deposited. As the water continues to slow, more and more rocks are deposited. The smallest material is deposited last. More and more material is deposited. The material piles up. The first material deposited is compressed and eventually turned into rock. the drawing below shows how all this is done.
Sorting Figure
The grains are deposited based on their size and density.
During burial of the sediment, the loose material is consolidated by pressure and a cementing agent such as Calcite or Quartz. This is called Lithification.
When clastic rocks form there are air spaces between the grains called Pores.
The smaller the grains, the smaller the pores.
Porous rock can contain water. This type of rock is called an Aquifer.
Permeable Rock: water can pass through it.
Impermeable Rock: water can not pass through it.
Artesian wells are wells that are drilled into solid rock. The sandstone (permeable) is sandwiched between two layers of impermeable rock(shale). Water enters the rock from miles away. As the water travels through the rock, it is purified and it is put under pressure. When you drill into the rock, you generally don't need a pump to get the water to the surface. Since the water is under pressure, the pressure forces it to the surface.
Artesian wells
Artesian Well
Symbols for rocks
When making geologic drawings, we use symbols to indicate the kind of rock that it is.
Rock symbols
Rock Symbols
It was mentioned earlier that people that were interested in rocks did not use scientific methods to understand them. For one thing, there weren't scientific principles for use in geology. Listed below are some simple but important principles that have been developed.
Principle of Superposition: the oldest rocks are found in the lowest strata; we number the strata from the oldest to the youngest. The lower the number, the older the rock.
Super Position
Fossil Correlation: the various strata can be identified by the fossils that they contain.
Rock layers can be hundreds of miles long. If the strata is of the same age, it will have the same type of fossils in it. If a layer of sandstone form from the sand found on a beach, it is not likely to have fossils of clams and camels in the same strata.
Fossil correlation
Fossil Correlation
Fossil correlation 2
Fossil Correlation
Maybe you can see why Fossil Correlation is important. In the drawing above, the rocks have been eroded. The center section has been eroded away. If we try to match the rock strata on the left with the rock strata on the right, do they all match up ? The rock type do but not the fossils. Look at the 3rd layer from the top. They have two different types of fossils. Therefore they are not of the same age. They did not form at the same time.
Limestone is a rock type that dissolves easier then most rocks. Rain water is slightly acid(carbonic acid). Dissolving the calcite in the limestone creates air pockets. If the limestone has cracks in it, the water can make its way to great depts. As the water makes it way through the limestone, the carbonic acid slowly dissolves the limestone and carries ions away in solution. After thousands of years, the cracks between beds become so large that they form networks of underground tunnels, sometimes hundreds of miles long
Karst Topography
Karst topography
Karst Topography
In limestone regions, most of the water sinks into the ground through cracks and sinkholes. These regions generally have few surface rivers. Lost rivers are formed when surface rivers disappear underground and flow out of caves many miles away. Regions that contain many sinkholes, sinkhole ponds, lost rivers, underground drainage, and natural bridges are said to have Karst Topography. A sinkhole is nothing more than a cavern that has collapsed.
Geysers are boiling hot springs that occasionally erupts. The geyser's tubes have a lot of narrow tubes. They act as though they are blocking the flow of water upward. Because of the constriction, the water at the bottom of a geyser's tube is under pressure. The water becomes superheated to a temperature above the boiling point. But due to the pressure the superheated water can not turn to steam. Finally the water becomes so hot that it overcomes the pressure and turns to steam. When this happens, the steam forces some of the water up to the surface. The pressure at the bottom of the tube is relieved, and the superheated water explodes into steam. The steam blows out the water above it.
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Astronomy 123: First Homework Assignment
Provide some information in response to the following questions. Such information can be generally found by using an Internet search engine and typing in a key word or phrase related to the question.
1. What are the principle differences between Galileo and Aristotle's concept of motion and the origin of motion?
2. How did Einstein's new theory help to resolve the dilemma posed by discovering that the orbit of Mercury did not conform to Newton's Laws.
3. Using this resource provide an overview of Aristotle's notion of an ordered Universe as well as an overview of the Ptolemaic model.
4. Who was Bruno and what kinds of things did he write about in a way that caused him to be burned at the stake in the year 1600.?
5. Summarize the Shapley-Curtis debate and its implications on the overall size of our Galaxy and the size of the Universe.
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The remoras /ˈrɛmərəz/, sometimes called suckerfish, are a family (Echeneidae) of ray-finned fish in the order Perciformes.[2][3] They grow to 7–75 cm (2.8 in–2 ft 5.5 in) long. Their distinctive first dorsal fins take the form of a modified oval, sucker-like organ with slat-like structures that open and close to create suction and take a firm hold against the skin of larger marine animals.[4] The disk is made up of stout, flexible membranes that can be raised and lowered to generate suction.[5] By sliding backward, the remora can increase the suction, or it can release itself by swimming forward. Remoras sometimes attach to small boats, and have been observed attaching to divers as well. They swim well on their own, with a sinuous, or curved, motion.
Temporal range: Late Oligocene – Recent[1]
Remora remora
Common remora, Remora remora
Scientific classification
Remora front dorsal fins have evolved to enable them to adhere by suction to smooth surfaces and they spend their lives clinging to a host animal such as a whale, turtle, shark or ray. It is probably a mutualistic arrangement as the remora can move around on the host, removing ectoparasites and loose flakes of skin, while benefiting from the protection provided by the host and the constant flow of water across its gills.[6] Although it was initially believed that remoras fed off particulate matter from the host's meals, this has been shown to be false; in reality, their diets are composed primarily of host feces.[7]
Echeneis naucrates Indonesia
Some remoras, such as this Echeneis naucrates, may attach themselves to scuba divers.
Remoras are tropical open-ocean dwellers, but are occasionally found in temperate or coastal waters if they have attached to large fish that have wandered into these areas. In the mid-Atlantic Ocean, spawning usually takes place in June and July; in the Mediterranean Sea, it occurs in August and September. The sucking disc begins to show when the young fish are about 1 cm (0.4 in) long. When the remora reaches about 3 cm (1.2 in), the disc is fully formed and the remora can then attach to other animals. The remora's lower jaw projects beyond the upper, and the animal lacks a swim bladder.[2]
Some remoras associate with specific host species. They are commonly found attached to sharks, manta rays, whales, turtles, and dugongs, hence the common names "sharksucker" and "whalesucker". Smaller remoras also fasten onto fish such as tuna and swordfish, and some small remoras travel in the mouths or gills of large manta rays, ocean sunfish, swordfish and sailfish.
The relationship between a remora and its host is most often taken to be one of commensalism, specifically phoresy.
Research into the physiology of the remora has been of significant benefit to the understanding of ventilation costs in fish.
Remoras, like many other fishes, have two different modes of ventilation. Ram ventilation[8] is the process in which at higher speeds, the remora uses the force of the water moving past it to create movement of fluid in the gills. Alternatively, at lower speeds the remora will use a form of active ventilation,[8] in which the fish actively moves fluid through its gills. In order to use active ventilation, a fish must actively use energy to move the fluid; however, determining this energy cost is normally complicated due to the movement of the fish when using either method. As a result, the remora has proved invaluable in finding this cost difference (since they will stick to a shark or tube, and hence remain stationary despite the movement or lack thereof of water). Experimental data from studies on remora found that the associated cost for active ventilation created a 3.7–5.1% increased energy consumption in order to maintain the same quantity of fluid flow the fish obtained by using ram ventilation.[9]
Other research into the remora's physiology came about as a result of studies across multiple taxa, or using the remora as an out-group for certain evolutionary studies. Concerning the latter case, remoras were used as an outgroup when investigating tetrodotoxin resistance in remoras, pufferfish, and related species, finding remoras (specifically Echeneis naucrates) had a resistance of 6.1–5.5×108 M.[10]
Use for fishing
Some cultures use remoras to catch turtles. A cord or rope is fastened to the remora's tail, and when a turtle is sighted, the fish is released from the boat; it usually heads directly for the turtle and fastens itself to the turtle's shell, and then both remora and turtle are hauled in. Smaller turtles can be pulled completely into the boat by this method, while larger ones are hauled within harpooning range. This practice has been reported throughout the Indian Ocean, especially from eastern Africa near Zanzibar and Mozambique,[11] and from northern Australia near Cape York and Torres Strait.[12][13]
Similar reports come from Japan and from the Americas. Some of the first records of the "fishing fish" in the Western literature come from the accounts of the second voyage of Christopher Columbus. However, Leo Wiener considers the Columbus accounts to be apocryphal: what was taken for accounts of the Americas may have been, in fact, notes Columbus derived from accounts of the East Indies, his desired destination.[14]
In ancient times, the remora was believed to stop a ship from sailing. In Latin, remora means "delay", while the genus name Echeneis comes from Greek εχειν, echein ("to hold") and ναυς, naus ("a ship"). In a notable account by Pliny the Elder, the remora is blamed for the defeat of Mark Antony at the Battle of Actium and, indirectly, for the death of Caligula.[15] A modern version of the story is given by Jorge Luis Borges in Book of Imaginary Beings (1957).
Remora SI
Remora Belize Reef
Live sharksucker, Echeneis naucrates
Remora remora 1
Common remora, Remora remora
Nurse shark with remoras
Nurse shark with remoras attending
See also
1. ^ Friedman, Matt, et al. "An early fossil remora (Echeneoidea) reveals the evolutionary assembly of the adhesion disc." Proc. R. Soc. B 280.1766 (2013): 20131200.
2. ^ a b Froese, Rainer, and Daniel Pauly, eds. (2013). "Echeneidae" in FishBase. April 2013 version.
3. ^ "Echeneidae". Integrated Taxonomic Information System. Retrieved 20 March 2006.
4. ^ "Sharksucker fish's strange disc explained". Natural History Museum. 28 January 2013. Archived from the original on 1 February 2013. Retrieved 5 February 2013.
5. ^ Beer, Amy-Jane. Derek Hall. (2012). The Illustrated World Encyclopedia of Marine Fish & Sea Creatures. Leicestershire: Lorenz Books. p. 235. ISBN 978-0-7548-2290-5.
6. ^ Jackson, John (30 November 2012). "How does the Remora develop its sucker?". National History Museum. Retrieved 2 January 2016.
7. ^ Williams, E. H.; Mignucci-Giannoni, A. A.; Bunkley-Williams, L.; Bonde, R. K.; Self-Sullivan, C.; Preen, A.; Cockcroft, V. G. (2003). "Echeneid-sirenian associations, with information on sharksucker diet". Journal of Fish Biology. 63 (5): 1176. CiteSeerX doi:10.1046/j.1095-8649.2003.00236.x.
8. ^ a b Willmer, Pat; Stone, Graham; Johnston, Ian (2009-03-12). Environmental Physiology of Animals. John Wiley & Sons. ISBN 9781444309225.
9. ^ Steffensen, J. F.; Lomholt, J. P. (1983-03-01). "Energetic cost of active branchial ventilation in the sharksucker, Echeneis naucrates". Journal of Experimental Biology. 103 (1): 185–192. ISSN 0022-0949. PMID 6854201.
10. ^ Kidokoro, Yoshiaki; Grinnell, Alan D.; Eaton, Douglas C. (1974). "Tetrodotoxin sensitivity of muscle action potentials in pufferfishes and related fishes". Journal of Comparative Physiology. 89: 59. doi:10.1007/BF00696163.
11. ^ Gudger, E. W. (1919). "On the Use of the Sucking-Fish for Catching Fish and Turtles: Studies in Echeneis or Remora, II., Part 1". The American Naturalist. 53 (627): 289–311. doi:10.1086/279716. JSTOR 2455925.
12. ^ Gudger, E. W. (1919). "On the Use of the Sucking-Fish for Catching Fish and Turtles: Studies in Echeneis or Remora, II., Part 2". The American Naturalist. 53 (628): 446–467. doi:10.1086/279724. JSTOR 2456185.
13. ^ MacGillivray, John (1852). Narrative of the Voyage of H.M.S. Rattlesnake, Commanded By the Late Captain Owen Stanley, R.N., F.R.S. Etc. During the Years 1846–1850. 2. London: Lords Commissioners of the Admiralty. (Dr. Gudger's accounts are more authoritative, but this source is noted as an early account that Gudger appears to have missed.)
14. ^ Wiener, Leo (1921). "Once more the sucking-fish". The American Naturalist. 55 (637): 165–174. doi:10.1086/279802. JSTOR 2456418.
15. ^ Pliny the Elder. "Book 32, Chapter 1". Natural History. (cited in Gudger, E. W. (1930). "Some old time figures of the shipholder, Echeneis or Remora, holding the ship". Isis. 13 (2): 340–352. doi:10.1086/346461. JSTOR 224651.)
Australian Submarine Rescue Vehicle Remora
Australian Submarine Rescue Vehicle Remora (ASRV Remora) was a submarine rescue vehicle used by the Royal Australian Navy (RAN) between 1995 and 2006. The name comes from the remora, a small fish that can attach itself to larger marine life, and has the backronym "Really Excellent Method Of Rescuing Aussies".Remora was constructed by OceanWorks International of North Vancouver, British Columbia for the RAN, based on a diving bell. The 16.5-tonne (18.2-ton) vehicle was designed to mate with a submarine's escape tower, and could do this even if the submarine had rolled up to 60 degrees from vertical. The vehicle can operate at depths over 500 metres (1,600 ft) and in currents of up to 3 knots (5.6 km/h; 3.5 mph), and was intended for use below 180 metres (590 ft); the maximum safe depth for Submarine Escape Immersion Equipment. The submersible carried seven people: an onboard operator and six passengers. Those aboard Remora were kept under about five bars of pressure, and rescued submariners exited into one of two 36-man recompression chambers carried aboard the rescue ship.Remora could be controlled from a containerised facility aboard the rescue ship, with power, control, and sensors fed through an armoured umbilical cable. Twelve personnel make up the surface control complement, with this number supplemented by underwater medicine specialists and divers. The entire setup (Remora, control centre, and recompression chambers) could be transported by road or sea, or loaded into C-130 Hercules aircraft. Remora could be delivered to anywhere in Australia within 36 hours, and installed on a suitable vessel in another 25 hours. The Defence Maritime Services tender Seahorse Spirit was designated the main tender for Remora, although any vessel with sufficient space to carry and deploy the equipment (300-square-metre (3,200 sq ft) of deck space, with 8 metres (26 ft) minimum width) could be used.In December 2006, the umbilical cable parted during an exercise off Perth, trapping two men at a depth of 140 metres (460 ft) for 12 hours. The men were rescued, but Remora was not recovered until April 2007. The submersible was sent back to OceanWorks for repairs. Although repairs were completed, Remora did not reenter service as the Det Norske Veritas classification society refused to certify the submersible; the launch and recovery equipment did not meet updated safety standards. As of the end of 2008, Remora was in storage at Henderson, Western Australia. To cover the capability loss, the Department of Defence arranged for the British LR5 submersible to be flown to Australia if submarine rescue was required. In June 2009, LR5 was relocated to Australia on lease.Remora was the basis for the United States Navy's Submarine Rescue Diving Recompression System.
Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit from each other, amensalism, where one is harmed while the other is unaffected, and parasitism, where one benefits while the other is harmed. The commensal (the species that benefits from the association) may obtain nutrients, shelter, support, or locomotion from the host species, which is substantially unaffected. The commensal relation is often between a larger host and a smaller commensal; the host organism is unmodified, whereas the commensal species may show great structural adaptation consonant with its habits, as in the remoras that ride attached to sharks and other fishes. Both remora and pilot fish feed on the leftovers of their hosts' meals. Numerous birds perch on bodies of large mammal herbivores or feed on the insects turned up by grazing mammals.
Common remora
The common remora (Remora remora) is a pelagic marine fish belonging to family Echeneidae. The dorsal fin, which has 22 to 26 soft rays, acts as a suction cup, creating a vacuum to allow it to attach to larger marine animals, such as whales, dolphins, sharks, and sea turtles.
An echeneis is a legendary creature; a small fish that was said to latch on to ships, holding them back.
Pliny the Elder (1st century AD) also said of the echeneis: "It has a disgraceful repute, as being employed in love philtres, and for the purpose of retarding judgments and legal proceedings—evil properties, which are only compensated by a single merit that it possesses—it is good for staying fluxes of the womb in pregnant women, and preserves the fœtus up to birth: it is never used, however, for food." They were said to be found in the Indian Ocean. Isidore of Seville (7th century AD) and Bartholomaeus Anglicus (13th century) are among later authors of bestiaries that mention the echeneis.It is thought that these ancient descriptions refer to the remora.
Fins (song)
"Fins" is a song performed by American popular music singer-songwriter Jimmy Buffett. It was written by Buffett, Coral Reefer Band members Deborah McColl and Barry Chance, and author Tom Corcoran. It was released as a single (b/w "Dreamsicle") on MCA 41109 in July 1979.
It was first released on his 1979 album Volcano. It reached number 35 on the US Billboard Hot 100 and number 42 on the Easy Listening chart.
The title refers to the fins of metaphorical sharks, i.e. "land sharks", men who attempt to pick up the woman who is the subject of the song. She is said to feel like a remora due to the proximity of the predators.
"Fins" is one of Buffett's more popular songs with fans, and is part of "The Big 8" that he has played at almost all of his concerts. Recorded live versions of the song appear on Feeding Frenzy, Buffett Live: Tuesdays, Thursdays, Saturdays, and the video Live by the Bay. Buffett usually begins the song with a few bars of the "Main Title" theme from the movie Jaws. Concertgoers typically respond to the chorus line of "fins to the left, fins to the right" by extending their arms above their heads in a fin shape and moving them from left to right. Fin and shark themes have become a prominent part of parrothead (Buffett fan) clothing and gear and feature in several of Buffett's commercial ventures such as Land Shark Lager beer.
In 2009, Buffett wrote new lyrics to the song for the Miami Dolphins football team. The song is played during home games at Sun Life Stadium, and is used in tandem with the Dolphins' fight song after every touchdown the team scores.
List of A Series of Unfortunate Events characters
The author of the series is Lemony Snicket (the nom de plume of Daniel Handler), who plays a major role in the plot himself. Although the series is given no distinct location, other real people appear in the narrative, including the series' illustrator, Brett Helquist, and Daniel Handler himself.
Marlin sucker
The marlin sucker or spear-fish remora (Remora osteochir) is a species of remora found all over the world in tropical and temperate seas. It can reach up to 40 cm (16 in) in standard length. It normally lives attached to a larger fish; its host preference is for marlins (as the name implies) and sailfishes, but it will attach to other large fish.
Remora (genus)
Remora is a genus of remoras native to temperate to tropical marine waters worldwide.
Richard Baluyut
Richard Baluyut (born April 26, 1966 in Baltimore, MD) is a US singer and guitarist. He is best known as the lead singer and guitarist for Versus from 1990 onwards, but he was also a singer/guitarist for Flower between 1986 and 1990 and the lead singer and guitarist for Whysall Lane. He composed the soundtrack for the film Midas' Son. With Jeff Cashvan he co-owned Remora Records, which in the early 1990s released singles and EPs by New York City indie bands such as Babytooth. He is the brother of James Baluyut and Edward Baluyut.
Safe Havens
Safe Havens is a comic strip drawn by cartoonist Bill Holbrook. It was originally syndicated by Washington Post Writers Group in 1988 as a weekday only strip (opposite the Sunday only strip Outland by Berkeley Breathed), the strip switched to King Features Syndicate in 1993.The strip has been published in more than 50 newspapers. The strip originally concerned the group of pre-schoolers at Safe Havens Day Care, but has focused on Samantha and followed her as she has grown up (approximately in real-time) and gone through elementary school, high school, college, and (currently) marriage. The comic then went online in 2010.
The strip is located near the seashore in the fictional city of Havens, several hundred miles from the state capital. However, in 2018 the setting changed to a spaceship on a manned mission to Mars that is expected to last until 2021.
Shadow Raiders
Disambiguation: Shadow Raiders is also the title of the first book in the Dragon Brigade series.Shadow Raiders is a Canadian animated television series produced by Mainframe Entertainment (now known as Rainmaker Entertainment) and syndicated by The Summit Media Group, that aired from September 16, 1998 to June 23, 1999. The show was loosely based on the Trendmasters toy line, War Planets. The original character designs were created by ReBoot designer, Brendan McCarthy. The series focused on the four warring planets of a solar system called the Cluster as they were forced to set aside their differences and form a coalition against the menace of the Beast Planet.
Spearfish remora
The spearfish remora (Remora brachyptera) is a species of remora with a worldwide distribution in tropical and subtropical seas. Remoras attach themselves to other fish with a sucker on the head and this fish is almost exclusively found living on billfishes or swordfishes, and sometimes on sharks.
Stravaganza (series)
Stravaganza is a series of novels written by children's author Mary Hoffman. The books are set alternatively between Islington, an area of London, England, and various cities in Talia, an alternate version of Renaissance Italy.
The series originally consisted of a trilogy of books: City of Masks, City of Stars, and City of Flowers. The popularity of the trilogy allowed the series to be extended for three more books: City of Secrets, City of Ships, and City of Swords.
Submarine Rescue Diving Recompression System
The Submarine Rescue Diving Recompression System (SRDRS) is a remotely operated underwater vehicle and its associated systems intended to replace the Mystic class deep submergence rescue vehicle for the United States Navy. Based on the Royal Australian Navy Submarine rescue vehicle Remora, the system is capable of rapidly deploying to a designated location, mounting to a vessel of opportunity, detecting and preparing the area around a downed submarine and submerging to great depths (2000ft/600m) to give aid and retrieve members of its crew. The SDRS then allows for the decompression of the crew.
USS Remora
USS Remora (SS-487), a Tench-class submarine, was the only ship of the United States Navy to be named for the remora, a fish with a suctorial disk on its head enabling it to cling to other fish and to ships. Her keel was laid down on 5 March 1945 by the Portsmouth Navy Yard in Kittery, Maine. She was launched on 12 July 1945 sponsored by Mrs. T. W. Samuels, III, and commissioned on 3 January 1946 with Commander Robert Sellars in command.
The whalesucker (Remora australis) is a species of remora in the family Echeneidae, so named because it attaches itself exclusively to cetaceans. It is found worldwide in tropical and warm waters; in the Gulf of Mexico and western Atlantic Ocean, it occurs from Texas to Brazil, and in the eastern Pacific Ocean, it occurs from Vancouver Island to Chile. It is the rarest member of the remora family, though this may reflect more the uncommon collection of cetaceans in the wild rather than the whalesucker's actual abundance.The adhesive disk atop the head of the whalesucker is the largest amongst the remoras, bearing 25-28 lamellae and measuring 47-59% of the standard length. The head itself measures 26-28% of the standard length. The dorsal fin rays number 23-26, the anal fin rays 24-26, and the pectoral fin rays 22-24. The jaws contain numerous large, stout canine teeth; the palatine and lingual patches are absent, and there are 17-20 gill rakers. The coloration is uniform brown, dark brown, or greyish-brown on the head, trunk, and fins. Whalesuckers observed off Fernando de Noronha ranged from light grey to slate grey, with lighter fin margins. The smaller individuals are barred or blotched, while individuals over 35 cm long have yellowish fins. This species can reach 76 cm (30 in) in total length.The most common host of the whalesucker appears to be the blue whale. Chitinous material indicative of parasitic copepods or amphipods have been found in the stomachs of whalesuckers, suggesting a mutualistic relationship with their hosts. Off Fernando de Noronha, whalesuckers down to small (4 to 9 cm (1.6 to 3.5 in)) juveniles are associated with spinner dolphins, and are likely recruited year-round from flotsam. The whalesuckers, no more than three to a host, usually attach to the flanks or belly of the dolphin, which may serve to minimize drag and facilitate feeding. When approached, they, especially small individuals, will shift to the opposite side of the host for protection. Whalesuckers impose a hydrodynamic cost to their host, their adhesive disks can abrade the skin, and they sometimes attach to inconvenient locations, such as near the blowhole or the genitals. The spinning behavior of dolphins, sharks, and other remora hosts has been proposed as a means of dislodging them. The whalesuckers feed on parasites and sloughed-off skin, and also forage on feces and vomit from the dolphins.
White suckerfish
The white suckerfish or mantasucker (Remora albescens) is a species of remora in the family Echeneidae, a group of elongated marine fish with adhesive discs for attaching to larger organisms. The distribution of this species is worldwide in warm open seas: it is found in the western Indian Ocean including Réunion and Mauritius, in the eastern Pacific Ocean from San Francisco to Chile (but is rare north of Baja California), and in the western and eastern central Atlantic Ocean from Florida and the Gulf of Mexico to Brazil and St. Paul's Rocks.The white suckerfish can reach 30 cm (12 in) in standard length. The adhesive disk is short and wide, the length 34-40% and the width 22-26% of the standard length, with 13-14 lamellae. The pelvic fins are placed far forward and narrowly attached to the abdomen; the dorsal, anal, and pectoral fins are short with reduced rays. The dorsal fin rays number 18-23, the anal fin rays 18-24, and the pectoral fin rays 18-21. The dentition is specialized, consisting of many large, stout canine teeth set in large patches in broad jaws. The head, body, and fins are colored light brown, light tan, or light grey to whitish. Three documented specimens from the Gulf of Mexico show considerable variation in color pattern, from uniform grey or pale bluish-white to light grey, darkening on the sides and belly and bearing numerous elongated spots. One living specimen immediately darkened in color when it was removed from sea water and lightened when it was returned.White suckerfish are rarely found free-swimming; they are host-specific to manta rays, and enter their host's mouth and gill chamber more often than any other remora. They are also occasionally found attached to sharks, and in the Indo-Pacific region to black marlin. Unlike some other remora species, parasitic copepods comprise a negligible part of the diet of the white suckerfish, suggesting it may not have a mutualistic relationship with its host. The white suckerfish responds to a touch on its belly by forcefully erecting its pelvic fins, possibly an adaptation to avoid crushing by its host. Nothing is known about their reproduction. It is used in Chinese medicine.
Images, videos and audio are available under their respective licenses.
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Anatomy and Physiology: The More Things Change …
The More Things Change …
Bones can be very surprising. The simple fact that bones can repair themselves seems almost miraculous! Imagine, if you can, being able to pay a little more for a car that actually fixes itself! Simply put, bones are not the dried up sticks you thought they were, but rather complex and dynamic structures.
Bone Development
Bone development is a multistep process from hyaline cartilage to compact and spongy bone. The process is a bit like the opposite of certain hard candies, for bone starts out soft, with the hard part starting in the center:
1. Bone starts as hyaline cartilage. Chondrocytes in the diaphysis enlarge and then die, leaving cavities in their wake.
2. Perichondral cells (around the cartilage) turn into osteoblasts and begin to form a bony outer layer, and blood vessels start to grow around the edge of the developing bone.
3. Blood vessels start to grow in the central region of the bone, and fibroblasts become osteoblasts in the same region and start to build spongy bone in a region called the primary ossification center. This process spreads toward the epiphyseal regions.
4. The spongy bone in the center is broken down by osteoclasts, forming the marrow cavity. The bone grows longer and wider.
5. Osteoblasts and capillaries begin to infiltrate the epiphyses, producing secondary ossification centers.
6. The cartilage in the epiphyses is replaced by spongy bone, and the epiphyseal plate forms in the metaphysis. Eventually compact bone forms around the perimeter of the bone, leaving the epiphyseal plate as the area for bone growth.
Making and Breaking
Medical Records
One of the coolest things about our fetal development is what happens to our tail! As you will see in The Joints, we do indeed have a tail! Our tail, known as the coccyx, is extremely short (between three to five fused vertebrae). When we are an embryo we grow a longer tail, only to destroy it during development! Why waste all that time and energy? The answer? Evolution! Our evolutionary ancestors had tails, and some of our development contains vestiges (vestigial structures) from our evolutionary past!
The histology of bone is cool because people think of growth as a constructive process. Growth makes perfect sense because bones get longer, but what about the width? The width of a bone increases, but at the same time something has to happen to the medullary (marrow) cavity. If the medullary cavity walls all grew inward, the cavity would fill up during childhood. In order to have a medullary cavity the same relative size as the bone grows, the width of the cavity must increase. The only way to do that is to literally destroy the cells that line the walls of the cavity.
All of these changes require different cell types. Since bone is basically connective tissue, we should talk a little about the matrix that separates the cells. The matrix in bone is about 1/2 mineral salts, 1/4 protein fibers, and 1/4 water. Water? Yes! Bone cells are alive, and to stay alive they need to have contact with the cardiovascular system. Each cell is bathed in interstitial fluid, which flows throughout the haversian system in all the canaliculi described previously.
The Big Picture
Two hormones are responsible for calcium homeostasis: parathyroid hormone (PTH) from the parathyroid glands increases blood calcium levels, and calcitonin from the thyroid decreases blood calcium levels. PTH stimulates osteoclasts to break down the matrix, thus releasing calcium. Calcitonin, on the other hand, inhibits osteoclasts. This leaves the osteoblasts free to deposit the calcium in bone. As such, which hormone would you expect to be prescribed to patients with osteoporosis? That's right, calcitonin!
There are four types of bone cells. First of all, connective tissues all derive from an undifferentiated form called mesenchyme. From this mesenchyme there is an undifferentiated bone cell called an osteoprogenitor cell. These cells are found in both the periosteum and the endosteum, as well as the various canals that carry blood throughout bone.
Osteoprogenitor cells divide (through mitosis) and can develop into bone building cells called osteoblasts. Although they cannot divide, they can secrete collagen necessary for bone building. As they build bone and become surrounded by the matrix, they eventually stop making collagen and become the main cells in bone: osteocytes (osteo = bone and cyte = cell).
The last type of bone cell is thought to come from a type of white blood cell called a monocyte. These cells migrate all over the body, eventually becoming macrophages. Some of these end up in bone, and become somewhat iconoclastic bone-breaking cells called osteoclasts. It is the osteoclasts in the endosteum that destroy the matrix of the bone lining the medullary cavity, thus making it wider as the bone grows larger.
Medical Records
Bones respond to stress by increasing osteoblast activity. A highly active person will have more pronounced bone landmarks, particularly where muscles attach, due to the increased stresses there. One unusual thing about the bone matrix crystals is that they produce a tiny electrical field when stressed, and osteoblasts are attracted to the field, and once there they start to produce bone. Doctors have used this to their advantage by stimulating bone growth electrically in particularly bad fractures.
Out with the Old …
Osteoblasts and osteoclasts are busy little critters. Due to the need for a certain level of calcium in the body, especially in terms of muscle contraction (see The Structure of the Muscles and Muscle Cells), the matrix in bone needs to be continually broken down (to release calcium) and rebuilt (to deposit calcium). This continual activity is called remodeling.
Remodeling usually occurs at a balanced rate, which means for every osteon broken down, another is rebuilt. The rate of turnover varies according to the location of the bone, as well as the part of the bone, but about 20 percent of the bone tissue in a young adult is remodeled in a year. Areas of bone that receive a lot of stress, such as the spongy bone in the head of the femur can be replaced in anywhere from 4 to 6 months, but the compact bone in the diaphysis, which receives far less stress, is hardly changed at all.
Given the increase in bone density in response to stress, an active person can build stronger bone. Young women who are very active can actually reduce their risk of developing osteoporosis (the thinning of bone matrix, most commonly in older women) in their later years. One cause of osteoporosis is not having enough dietary calcium during pregnancy; the baby's need to build bone will cause the mother to draw calcium from her own bones, causing them to become more porous—osteoporosis means porous bone.
Another far less common way to reduce bone density is to become an astronaut! In order to mimic the effect of gravity on bone, an astronaut would have to exercise for about eight hours a day to prevent bone loss; as that is not possible, a typical astronaut is asked to exercise only two hours a day! For this very reason, physical therapy for women with osteoporosis involves a great deal of weight-bearing exercises; the greater the stress, the busier the osteoblasts!
book cover
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Gerri Chanel
In August 1939, curators at the Louvre nestled the world's most famous painting into a special red velvet-lined case and spirited her away to the Loire Valley. So began the biggest evacuation of art and antiquities in history.
As the Germans neared Paris in 1940, the French raced to move the masterpieces still further south, then again and again during the war, crisscrossing the southwest of France. Throughout the German occupation, the museum staff fought to keep the priceless treasures out of the hands of Hitler and his henchmen, often risking their lives to protect the country's artistic heritage. Thus a story that features as a vignette in the George Clooney film The Monuments Men is given the full-length treatment it demands.
Call number: 940.5344 C
This title is also available as an eBook.
Essay: Saving Mona Lisa: The Battle to Protect the Louvre and Its Treasures from the Nazis
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"url": "https://www.ville.mont-royal.qc.ca/en/books/saving-mona-lisa-battle-protect-louvre-and-its-treasures-nazis"
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