text
stringlengths 208
322k
| id
stringlengths 47
47
| metadata
dict |
|---|---|---|
Pollution: secrets under Paris
Home Technologist 07 Pollution: secrets under Paris
French researchers have found that underground geological formations can act as historical archives for heavy-metal pollution.
Aqueduc Paris
What did the Paris environment look like hundreds of years ago? For Emmanuel Dumont the answer might be found in a maze of aqueducts built in the Middle Ages under Belleville, a neighbourhood in northeastern Paris. “We’re in the presence of a construction that has not changed for centuries,” he says. “And the water is still running.” A hydrogeologist at the Centre for Risk, Environment, Mobility and Development, Dumont believes the sediments on the aqueduct walls hold the clues.
Dissolved limestone builds up over time into stalactite-like geologic formations called speleothems. Each successive layer traps traces of elements carried by water from the surface through the soil, taking a rock-solid snapshot of a given moment. Scientists have long used speleothems as proxies for atmospheric carbon dioxide or sulphur from volcanic eruptions. But formations were only recently found to also retain evidence of human activity, like coal burning in Italy and pre-Roman lead mining in Great Britain.
The Parisian team is the first to use urban speleothems to measure levels of heavy-metal pollution. In samples from the walls under Belleville, they have identified aluminium, copper, cadmium, magnesium and lead going back 300 years. Their analyses show that lead levels were high in the 18th century, then dropped before picking back up in the mid-20th century.
These findings have surprised historians who study Paris’s pollution. The lead might have come from local artisans who used the soft metal to craft caskets and other funeral accessories. Another source could be city waste: In the 18th century, a garbage dump in nearby Montfaucon provided fertiliser for the surrounding farming activities.
Paris’s underground could hold many other similar speleothems. “We can keep going further back, beyond the Middle Ages,” said Edwige Pons-Branchu, who leads the project. “There are even traces of Roman aqueducts underneath Paris. If we could find a sample from that, it would just be too beautiful.”
Solving the world’s plastic problem with waxworms.
Gas to plastic
Finnish scientists learn to convert methane into animal feed or biodegradable polyester.
The power of dams
Hydro is the top source of renewable electricity in Europe, but environmentalists are concerned about the proliferation of new projects.
|
<urn:uuid:3fd57eea-3508-424f-8bac-12fb98fa5933>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.703125,
"fasttext_score": 0.05042928457260132,
"language": "en",
"language_score": 0.9296338558197021,
"url": "http://www.technologist.eu/secrets-under-paris/"
}
|
Predator and Prey
Some fossils show evidence of the violent relationships between predator and prey. Below is a brief discussion of a few of such fossils – fossils that seem to preserve the moment when a carnivore has killed its victim or scavenged a dead body for food.
Predator: Mosasaur
Prey: Ammonite
Modern mammals, fish, and reptiles feed on squid and octopus. Therefore, it can safely be assumed that ancient reptiles and fish fed on their ancient relatives – the ammonites. In fact, ammonites exhibiting bite marks are not uncommon. However, such bite marks are often mistaken by the collector as being just the result of random brakes in the shells. On the other hand, there have been claims of hundreds of ammonites with the preserved tooth marks of mosasaurs. Most of these claims are false. The marks on most of the shells are holes bored or dissolved in the ammonite by limpets or other forms of gastropods, rather then holes made from the bite of such reptiles.
Preditor and Prey 013Placenticeras sp. ammonite with limpet (insert) holes show a slightly dissolved and smooth edge to the shell around the holes.
The Placenticeras specimen, on the right, is a fine example of a mosasaur-bitten ammonite. The tooth marks have been left in the phragmocone (chambered portion) of the shell. Here, the septa still supports the surrounding shell as the bite did not result in the wide scale collapse of the shell around the holes. The edges of the holes show an irregular, slightly broken shape. This is very different from the smooth, round holes caused by limpet borings as seen in the Placenticeras ammonite on the left. Limpet (inset) holes show a slightly dissolved and smooth edge to the shell around the holes. Limpets and other gastropods that bore through shells stop dissolving the shell when they get through its the surface and reach the septa. They do not dissolve the underlying septa, as there is nothing further to gain by doing so.
Preditor and Prey 024Mosasaur-bitten Placenticeras sp.
Predator: Brittlestar
Prey: Crinoid
Crinoids possess an endoskeleton composed of calcareous plates covered by a thin epidermis. Each plate is a single, very porous calcite crystal. Unfused plates are held together with ligaments or muscles. The skeleton of a crinoid that lives on the sea floor may be divided into four basic parts: the holdfast that anchors the crinoid to the ocean bottom; the stem that raises the calyx above the substrate; the calyx that contains the internal organs; and from five to as many as 200 feeding arms that gather food.
Fossil crinoids are occasionally preserved with another organism attached, commonly a brittlestar entwined around the crown or near the anal pyramid. There is some debate among palaeontologists regarding this attachment. Some believe the relationship was commensal, meaning the brittlestar lived with the crinoid and consumed faecal pellets excreted by the crinoid as waste. However, other palaeontologists believe the brittlestar may have been predatory and fed on the crinoids themselves.
Below is a brittlestar, Onychaster (arrow), deeply embedded in the calyx of the crinoid Cyathocrinites.
Preditor and Prey 008Brittlestar, Onychaster sp. (arrow), deeply embedded in the calyx of the crinoid Cyathocrinites sp.
Predator: Albertosaur
Prey: Hadrosaur
Tooth-damaged dinosaur bone can be recognized by distinctive markings such as grooves or punctures. Although some damage may have been inflicted during dominance fights, most bite marks probably indicate carnivore activity. Identification of damaged bone can tell us that a particular species of dinosaur was eaten, but it generally does not indicate whether the prey was hunted and killed or opportunistically scavenged. However, in some cases, it may be possible to associate different tooth marks with specific predator activities based on the types and distribution of damage. For example, multiple bite marks on the ends of sauropod limb bones are more likely to represent feeding traces as opposed to assault wounds.
Preditor and Prey 006bHadrosaur bone fragment showing parallel striation marks, an indicator that the predator responsible had serrated teeth.
The identity of the animal responsible for bite marks is usually difficult to determine because many Mesozoic vertebrates (including crocodiles) were capable of causing generalized tooth damage to bone. Fortunately, well-preserved tooth marks can occasionally exhibit distinctive shapes, spacing, and/or serration marks that allow comparisons with fossil jaws of contemporaneous carnivores.
Preditor and Prey 017Albertosaur tooth specimen.
Parallel striation marks on the hadrosaur bone fragment (above left) indicate that the predator responsible for making these marks had serrated teeth as shown on the albertosaur tooth specimen.
Even more dramatic are the very rare examples of dinosaur teeth actually stuck in the bones of their prey. In Montana, a tyrannosaurid tooth was found embedded in a Hypacrosaurus fibula, providing more indisputable evidence of carnivore activity.
Buy Fossils, Crystals, Tools
Subscribe to Deposits
Join Fossil Hunts
UK Fossil Locations
|
<urn:uuid:3bd354b2-2355-40d0-b8ef-8baa0c4a5088>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.625,
"fasttext_score": 0.06614083051681519,
"language": "en",
"language_score": 0.9361485838890076,
"url": "https://depositsmag.com/2016/05/18/predator-and-prey/"
}
|
Scientists IDs genesis of animal behavior patterns
March 26, 2009 by Elizabeth Thomson
Map of the area off Georges Bank studied by MIT engineers and colleagues. Image / Makris Lab, MIT; Ratilal Lab, NU
The work, conducted using a novel imaging technique, "provides information essential to the conservation of that vast oceanic shoals inhabit," the team writes in the March 27 issue of Science.
It also confirms theories about the behavior of large groups of animals in general, from bird flocks to . Until now those theories had only been predicted through , computer simulations and laboratory experiments.
Schematic showing general setup of the imaging system used to study fish shoals. Graphic / Makris Lab, MIT; Ratilal Lab, NU
For example, the team found that once a group of fish reaches a critical population density, it triggers a kind of chain reaction resulting in the synchronized movement of millions of individuals over a large area. The phenomenon is akin to a human "wave" moving around a sports stadium.
"As far as we know, this is the first time we've quantified this behavior in nature and over such a huge ecosystem," said Nicholas C. Makris '83, PhD '91, leader of the work and a professor of mechanical and ocean engineering. The resulting shoals of can extend some 40 kilometers or approximately 25 miles across the ocean.
Makris' principal collaborators on the work include Purnima Ratilal PhD '02, a professor at Northeastern University, J. Michael Jech of the Northeast Fisheries Science Center, and Olav Rune Godoe of the Institute of Marine Research in Norway. Other collaborators are from MIT, Northeastern and the Southeast Fisheries Science Center.
Off Georges Bank
The researchers focused on off Georges Bank near Boston during the fall spawning season. They found that the formation and movement of large shoals of the fish constituted a kind of daily evening commute to the shallower waters of the bank where they spawn under cover of darkness. Come morning, the fish head back to deeper water and disband.
The work was conducted using Ocean Acoustic Waveguide Remote Sensing (OAWRS). In 2006, Makris and colleagues published a paper in Science introducing OAWRS, which they invented, and initial observations made with it.
OAWRS allows the team to take images of an area some 100 kilometers (approximately 62 miles) in diameter every 75 seconds. This is a vast improvement over conventional techniques such as fish-finding echo-sounders, which Makris compares to "watching one pixel on a movie screen" while the new technology allows you to "see the entire movie."
Both OAWRS and conventional methods rely on acoustics to locate objects by bouncing sound waves off of them. With conventional techniques, survey vessels send high-frequency sound beams into the ocean. In contrast, the new system uses much lower frequency sound that can travel much greater distances and still return useful information with signals far less intense.
Toward conservation
Makris sees potential in using OAWRS to better monitor — and conserve — fish populations. Large oceanic fish shoals provide vital links in the ocean and human food chain, he explained, but their sheer size makes it difficult to collect information using conventional methods.
Ron O'Dor, co-senior scientist of the Census of Marine Life (CoML), commented that "OAWRS allows us to gather information such as geographical distributions, abundance and behavior of fish shoals and to better understand what constitutes healthy fish populations ... which can be implemented by policymakers to better monitor and improve conservation of fish stocks."
CoML is an international scientific collaboration engaged in a 10-year initiative to assess and explain the diversity, distribution and abundance of marine life in the oceans. It aims to release the first Census of Marine Life in 2010.
Could OAWRS be exploited to find and take more fish, rather than conserve them? Makris believes that it would be virtually impossible. For example, he said, it cannot be used in stealth. "Thieves do not like to work in broad daylight or with the lights on, and OAWRS [essentially] turns the lights on in the ocean making it possible for everyone to see what is happening there and do something about it." He also emphasized that permission from each government would be needed to use it in any nation's territorial waters or in internationally regulated waters.
Source: Massachusetts Institute of Technology (news : web)
Explore further: One fish, two fish: New MIT sensor improves fish counts
Related Stories
Expedition discovers marine treasures
February 14, 2006
An underwater mountain that forms the world's third-largest atoll has some of the richest diversity of marine life ever found in the Caribbean, according to scientists who recently explored the area.
Study reveals secret sex life of fish
February 22, 2006
Recommended for you
Big brains in birds provides survival advantage: study
September 25, 2017
Given how proud we are of our big brains, it's ironic that we haven't yet figured out why we have them. One idea, called the cognitive buffer hypothesis, is that the evolution of large brains is driven by the adaptive benefits ...
Panda habitat shrinking, becoming more fragmented
September 25, 2017
A study by Chinese and U.S. scientists finds that while populations of the iconic giant panda have increased recently, the species' habitat still covers less area and is more fragmented than when it was first listed as an ...
With extra sugar, leaves get fat too
September 25, 2017
Eat too much without exercising and you'll probably put on a few pounds. As it turns out, plant leaves do something similar. In a new study at the U.S. Department of Energy's Brookhaven National Laboratory, scientists show ...
Click here to reset your password.
|
<urn:uuid:326294a0-f630-4468-b95f-1696c6fef343>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.671875,
"fasttext_score": 0.019118070602416992,
"language": "en",
"language_score": 0.9382166862487793,
"url": "https://phys.org/news/2009-03-scientists-ids-genesis-animal-behavior.html"
}
|
Pin Hole Camera
Only available on StudyMode
• Topic: Book of Optics, Pinhole camera, Camera obscura
• Pages : 3 (1068 words )
• Download(s) : 858
• Published : May 20, 2011
Open Document
Text Preview
Pin hole camera was invented by a Muslim scientist ibn-al-haitham.An Egyptian polymath (born in Iraq) whose research in geometry and optics was influential into the 17th century; established experiments as the norm of proof in physics (died in 1040).
Another inventor is the tenth century optician and physicist Abu Ali al-Hassan ibn al-Hassan ibn al-Haytham, simply known as al-Haytham, who invented the pinhole camera and discovered how the eye works. The ancient Greeks thought our eyes emitted rays, like a laser, which enabled us to see. The first person to realize that light enters the eye, rather than leaving it, was the 10th-century Muslim mathematician, astronomer and physicist Ibn al-Haytham. He invented the first pinhole camera after noticing the way light came through a hole in window shutters. The smaller the hole, the better the picture, he worked out, and set up the first Camera Obscura (from the Arab word qamara for a dark or private room). He was also credited with being the first man to shift physics from a philosophical activity to an experimental one.
Pinhole cameras are one of the earliest styles of camera ever created. So what is a pinhole camera? It is essentially a small-enclosed box with a tiny hole placed on one of the sides. When light is allowed to entire through the tiny hole, an image of the object directly outside the hole is projected onto the opposite side of the box. We will explore pinhole camera history a little deeper so you learn more about how they first came into being.
Many scientists and others observed and wrote about the phenomenon from the ancient Chinese to the Greeks. But it wasn't until the 11th century that someone actually wrote about the principals of the pinhole camera and created the camera obscura to study it. Ibn al-Haytham wrote his "Book of Optics" in 1021, and created his own pinhole camera, then later the camera obscura.
Al-Haytham discovered he could sharpen...
tracking img
|
<urn:uuid:5e159f12-aed3-4104-8b8f-ffbf41211b27>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.6875,
"fasttext_score": 0.109089195728302,
"language": "en",
"language_score": 0.9624698162078857,
"url": "http://www.studymode.com/essays/Pin-Hole-Camera-703258.html"
}
|
1651 – Cromwell’s forces triumph at Worcester
The final encounter of the English Civil War was a bruising and thorough defeat for King Charles the First and his allies. Although between them, the Royalist forces and their Scottish allies numbered about 16,000, Cromwell’s Parliamentarians had mustered nearly twice as many soldiers, and with such a massive numerical supreriority, the outcome was never truly in doubt.
Cromwell took his time in the disposition of his forces, cutting off the King’s escape while wearing down his army. In a battle that lasted only a single day, the Parliamentarians surrounded the Royalists, driving them back within the walls of the city of Worcester, and capturing it shortly after nightfall. Few if any of the Royalists escaped, most being captured at the battle’s end or later that night, but the truly stunning result were the casualty lists: Cromwell lost only 200 of his 31,000, while 3000 Royalists were slain and more than 10,000 captured. The English Civi War was over, and Charles I would not long outlive it, although he did escape for a time.
Referenced in:
Oliver Cromwell – Monty Python
|
<urn:uuid:3d4569e6-cd34-4a95-b441-affd5a8935f9>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5625,
"fasttext_score": 0.08840978145599365,
"language": "en",
"language_score": 0.9796631336212158,
"url": "http://thecentrecannothold.net/tag/1651/"
}
|
Origin Of ganga
Ganga in Hinduism
In Hinduism, the river Ganga (Sanskrit and Hindi: गंगा Gaṅgā) or Ganges River (as called by westerners) is considered sacred. It is worshipped by Hindus, and personified as a goddess in Hinduism, who holds an important place in the Hindu religion. Hindus believe that bathing in the river on certain occasions causes the remission of sins and facilitates the attainment of salvation. Many people believe that this effect obtains from bathing in Ganga at any time. People travel from distant places to immerse the ashes of their kin in the waters of the Ganga; this immersion also is believed to be meritorious as the ashes are believed to go to heaven. Several places sacred to Hindus lie along the banks of the river Ganga, including Karanwas, Haridwar, Allahabad and Varanasi. During the Loy Krathong festival in Thailand, candlelit floats are released into waterways in honoring the Buddha and the goddess Ganga for good fortune and washing away sins.
Birth of ganga-
There are several Hindu beliefs that give various versions of the birth of Ganga. According to one version, the sacred water in Brahma's Kamandalu became personified as a maiden, Ganga. According to another legend, Brahma had reverently washed the feet of Vishnu and collected this water in his Kamandalu. According to yet a third version, Ganga was the daughter of Himavan, king of the mountains, and his consort Mena; she was thus a sister of the goddess Parvati. Every version declares that she was raised in the heavens, under the tutelage of Brahma.
Persons who Descent ganga to Earth
The souls of the sons of Sagara wandered as ghosts since their final rites had not been performed. When Bhagiratha, one of the descendants of Sagara, son of Dilip, learnt of this fate, he vowed to bring Ganga down to Earth so that her waters could cleanse their souls and release them to heaven.
Bhagiratha prayed to Brahma that Ganga come down to Earth. Brahma agreed, and he ordered Ganga to go down to the Earth and then on to the nether regions so that the souls of Bhagiratha's ancestors would be able to go to heaven. The vain Ganga felt that this was insulting and decided to sweep the whole earth away as she fell from the heavens. Alarmed, Bhagiratha prayed to Shiva that he break up Ganga's descent.
Ganga arrogantly fell on Shiva's head. But Shiva calmly trapped her in his hair and let her out in small streams. The touch of Shiva further sanctified Ganga. As Ganga travelled to the nether-worlds, she created a different stream to remain on Earth to help purify unfortunate souls there. She is the only river to follow from all the three worlds - Swarga (heaven), Prithvi (earth) and, Patala (neitherworld or hell). Thus is called "Tripathagā" ( one who travels the three worlds) in Sanskrit language.
Because of Bhagiratha's efforts Ganga descended on to earth and hence the river is also known as Bhagirathi, and the term "Bhagirath prayatna" is used to describe valiant efforts or difficult achievements.
Another name that Ganga is known by is Jahnavi. Story has it that once Ganga came down to earth, on her way to Bhagiratha, her rushing waters created turbulence and destroyed the fields and the sadhana of a sage called Jahnu. He was angered by this and drank up all of Ganga's waters. Upon this, the Gods prayed to Jahnu to release Ganga so that she could proceed on her mission. Pleased with their prayers, Jahnu released Ganga (her waters) from his ears. Hence the name "Jahnavi" (daughter of Jahnu) for Ganga.
It is sometime believed that the river will finally dry up at the end of Kali Yuga (the era of darkness, the current era) just as with the Sarasvati river, and this era will end. Next in (cyclic) order will be the Satya Yuga or the era of Truth.
Saniya Binal said…
Bulandshahr is a historical city in Uttar pradesh. The distance between Haridwar and Bulandshahr is 226 kilometre and can be reached in 4 hours only.
Popular posts from this blog
Kalyani Devi Mandir Karanwas
History of Karanwas
Shri Ganga Mandir Karanwas
|
<urn:uuid:6ea1eb43-655f-4f27-90e5-e7fba559a65c>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.026586532592773438,
"language": "en",
"language_score": 0.9690685868263245,
"url": "http://karanwas.blogspot.com/2009/05/origin-of-ganga.html"
}
|
Egyptian Hieroglyphs
Reading Direction
Every written language needs rules to keep things readable. Hieroglyphs had their own conventions to keep writings consistent and understandable.
Reading Direction
Consistent reading direction is essential to readability.
English is always read left to right:
Hieroglyphs could be read either direction:
Reading direction was determined by human and animal hieroglyphs that appear in the writing. With hieroglyphic writings, hieroglyphs showing human and animals (and parts of humans and animals) all face the same direction.
The direction that hieroglyphic figures face dictates the reading sequence for that group of hieroglyphs. Reading starts from the direction that the characters face and proceeds towards those characters
reading-direction_LR_160x170reading-direction_RL_160x170Most commonly reading direction was from right to left. In this case, figures were right-facing. When human/animal characters are left-facing, reading direction is left to right.
Hieroglyphs are varying heights and widths. They can be nested together to reduce gaps. Shorter characters can be placed above one another to better fill the space. In this case, characters above are read before those below.
See the example:
Rows and Columns
Characters could be written in rows or columns, across the page or down the page. Rows and columns are separated by lines. Regardless of whether hieroglyphs are written in rows or columns, the reading order rules apply; reading direction starts in the direction animals and humans face, and hieroglyphs above are read first, then those below.
rows-hieros_300x300 columns-hieros_300x310
Please login to get access to the quiz
Vowels (Prev Lesson)
(Next Lesson) Bibliography
Back to Egyptian Hieroglyphs
Course Curriculum
|
<urn:uuid:3fe7fb9b-d80a-41a6-ac43-0e280a992956>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.90625,
"fasttext_score": 0.02883821725845337,
"language": "en",
"language_score": 0.8346019983291626,
"url": "http://www.greatscott.com/lessons/reading-direction/"
}
|
Historic World Events / April / Hostage rescue mission ends in disaster
Hostage rescue mission ends in disaster
Hostage rescue mission ends in disaster
On April 24, 1980, an ill-fated military operation to rescue the 52 American hostages held in Tehran ends with eight U.S. servicemen dead and no hostages rescued.
On November 4, 1979, the crisis began when militant Iranian students, outraged that the U.S. government had allowed the ousted shah of Iran to travel to the U.S. for medical treatment, seized the U.S. embassy in Tehran. The Ayatollah Khomeini, Iran’s political and religious leader, took over the hostage situation and agreed to release non-U.S. captives and female and minority Americans, citing these groups as among the people oppressed by the U.S. government. The remaining 52 captives remained at the mercy of the Ayatollah for the next 14 months.
President Carter was unable to diplomatically resolve the crisis, and the April 1980 hostage attempt ended in disaster. Three months later, the former shah died of cancer in Egypt, but the crisis continued. In November, Carter lost the presidential election to Republican Ronald Reagan, and soon after, with the assistance of Algerian intermediaries, successful negotiations began between the United States and Iran. On the day of Reagan’s inauguration, January 20, 1981, the United States freed almost $8 billion in frozen Iranian assets, and the 52 hostages were released after 444 days. The next day, Jimmy Carter flew to West Germany to greet the Americans on their way home.
READ Battle of Stalingrad ends
Source: History
|
<urn:uuid:f747709a-e597-496e-ae54-9ba23ed8799c>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.71875,
"fasttext_score": 0.022742748260498047,
"language": "en",
"language_score": 0.9634749889373779,
"url": "http://historicworldevents.com/april/hostage-rescue-mission-ends-in-disaster.html"
}
|
Starship chronology classroom chart
Silhouettes of several Earth and Federation starships
A starship was any manned spacecraft that was capable of viable interstellar travel, i.e. any manned spacecraft that has the ability to transport and support a crew across interstellar distances. Most starships accomplished this via the employment of some form of faster-than-light spacecraft propulsion technology, such as warp drive.
In the Federation during the 22nd and 23rd century, spacecraft of the Starship-class were identified exclusively as vessels operated by Starfleet, or as stated by R.M. Merik, "a very special vessel and crew". (TOS: "Bread and Circuses") By the mid-24th century though, the exclusivity of the term "starship" essentially fell out of use, and was redefined as a term interchangeable with spaceship and spacecraft. (Star Trek: The Next Generation, Star Trek: Deep Space Nine, Star Trek: Voyager)
Appendices Edit
See also Edit
External linkEdit
Ad blocker interference detected!
|
<urn:uuid:b5d50f31-d947-42f7-9473-5444e1d4e992>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.890625,
"fasttext_score": 0.10140037536621094,
"language": "en",
"language_score": 0.9605769515037537,
"url": "http://memory-alpha.wikia.com/wiki/Vessel"
}
|
The genus Cuscuta is composed of a large number of morphologically similar stem parasitic vines. They produce minute, scale-like leaves with flower structure that is often only discernable microscopically. The morphological reduction of Cuscuta has historically rendered them a taxonomically difficult group, although most authorities have agreed they are allied to Convolvulaceae (Morning Glories). Even molecular systematic approaches have proven confounding, as the chloroplast and nuclear genes most often used in broad phylogenies have been shown to evolve at accelerated rates in parasitic plants, sometimes leading to incorrect phylogenetic inferences. Mitochondrial gene and intron sequences have revealed a sister relationship of Cuscuta to members of Convolvulaceae rather than suggesting Cuscuta is nested within the family. A Nuclear ITS phylogeny provides insights into the relationships between the three traditionally recognized subgenera of Cuscuta along with a more detailed interspecific phylogeny. These relationships have a significant impact on the understanding of the evolution of parasitism and photosynthesis in Cuscuta.
Key words: Convolvulaceae, Cuscuta, ITS, mitochondrial DNA, parasitic plant, systematics
|
<urn:uuid:290b440a-ffaf-4751-b229-a720d51b6114>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.828125,
"fasttext_score": 0.5592460632324219,
"language": "en",
"language_score": 0.9185410737991333,
"url": "http://2000.botanyconference.org/section13/abstracts/227.shtml"
}
|
Literature Russian Term Paper
Excerpt from Term Paper :
Leo Tolstoy
During Leo Tolstoy's lifetime (1828-1910), Russia and Europe went through a number of political and intellectual changes. Writing evolved from Romanticism to Realism during the period. As the term "realism" implies the realistic novelists like Tolstoy focused on observation and attention to detail. In Russia the czars retained absolute power by preventing the political and social changes that the Western European countries were experiencing. Intellectuals including Tolstoy led the effort toward reform. The reform efforts met with considerable resistance until the twentieth century. For the writers, retention of power by the czars meant repression of writing. This repression had a severe impact on the realistic writers like Tolstoy who presented a true picture of political and social conditions. Nicholas I, who ruled until 1855, was particularly repressive. In spite of his conservatism, Russian literature experienced a tremendous upsurge during his reign and that of this son, Alexander II. In addition to Tolstoy, Pushkin, Gogol, Turgenev, and Dostoevsky contributed significantly to a literary "golden age" in Russia. In his later years, his religious conversion played an all-encompassing role.
In the early years of Tolstoy's writing, czar Nicholas I ruled Russia. He maintained a tight grip on power. He tolerated no dissent and employed secret police to see that his policies were obeyed. The hallmarks of his philosophy were the practice of state religion, the state above all else, and total dedication to the czar. In such an environment it would be expected that literature would suffer. However in spite Nicholas' best efforts literature flourished during his reign. Ironically the writers, including Tolstoy, born into gentry sought to undermine the Russian institutions. As mentioned in the first paragraph, realism marked the period when Tolstoy wrote his most famous novels, War and Peace and Anna Karenina. Realism entailed a dedication to accurately represent real life and real people. These were not topics that Nicholas wanted covered during his reign. The books exposed the inadequacies of Russian life under the strict leadership of the czars. The excessive detail of realistic writing successfully exposed the specific, individual, and particular as opposed to the general and the group.
Nicholas' preoccupation with maintenance of absolute power encouraged him to support any efforts by other countries to suppress revolution. Unfortunately for him this was a costly approach and eventually led to peasant revolts. Tolstoy's early efforts to enlighten peasants and have them protest their situation had been unsuccessful prior to Nicholas' ill-advised military efforts. This environment did not negatively influence Tolstoy's ability to express his feelings about the condition of peasants in Russia. Although realism was a reaction to romanticism, some elements of romanticism influenced Tolstoy's view of the world and his work. As with the romantics, Tolstoy saw over-civilized man as unnatural man who has drifted far away from the ideal man. On the other hand, man who is closest to nature is the natural man who should be considered much closer to ideal than the over-civilized man. The over-civilized man consists of materialistic and self-conscious motives, while the natural man operates in an unconscious environment. The over-civilized man resembles the selfish, over-privileged rich of the West. The natural man represents all that is noble about man.
Tolstoy's work focused on the psychological and broke down the most complex behavior into small comprehendible units. Tolstoy's interest in the natural man and his dislike for the institutions and culture that occupy the unnatural man creates a version of anarchism because all structure is disposed of. This approach also implies that Tolstoy's writing does not revolve around Russian issues of the day. All issues develop at the individual psychological level, not at the general societal level. Another implication of Tolstoy's focus on individual is his emphasis on clean, clear writing making his work relevant to the middle class. At the same time a great division between Russians who strove to emulate Western culture and those who felt that Russian had its' own unique qualities. The latter group represented the Slavophiles.
The problems associated with the serf economic system grew more and more difficult. Nicholas I recognized the fragile condition of serfdom. However he made no moves toward alleviating the problem. At the beginning of his reign, Alexander II started addressing the problem by appointing to committees to recommend what changes made sense. The Russian nobility stood in the way of reform and minimal changes occurred. The lack of real progress stimulated protest by the intellectuals such as Tolstoy. Tolstoy's acquaintance with peasants serving in the army showed the dual nature of his personality. In some of his books he presented peasants as hard-working people and then he would characterize them as lacking in trustworthiness. Regardless of this dual nature, Tolstoy constantly refined his skills of observation. This skill would eventually lead Tolstoy to honing his ability to affectively put reality into the words of his novels.
Tolstoy's experience in the military resulted in another aspect of realism. He saw heroism as another example of conscious and self-centered action instead of the ideal of unconscious action. Tolstoy's military experience also led him to document a soldiers' song degrading the performance of Russian officers during the disastrous Crimean War. Tolstoy's unmatched novel War and Peace epitomizes the themes that Tolstoy worked toward in his earlier writing. The elevation of the natural man and disgust with the over-civilized man underlies the novel. The quality that makes this great novel is Tolstoy's ability to improve on the presentation of realism in writing.
War and Peace marked a period when Tolstoy embarked on representing historical events through his writing. Tolstoy's gift to historical writing was his adherence to the facts of the Napoleonic wars. As always the true "heroes" of his novel are not the officers and commanders, but the everyday soldier who fights and really determines the outcome of battles and the outcome of the war. Tolstoy treats each character as an individual and paints a detailed picture of the numerous characters developed in the epic novel. Tolstoy's portrayal of the common soldiers as the true heroes created controversy when compared the traditional thinking that the decisions made by commanders determined the result of the war. The soldiers who were traditionally characterized as the heroes were simply unnatural men in Tolstoy's view. In later wars the reporting by correspondents showed the impact of Tolstoy's realistic representation of the Napoleonic war. Tolstoy's characterization of Napoleon as anything but a hero showed Tolstoy's consistent message that leaders who had thoroughly adopted Western culture were the unnatural men. These men had separated themselves from the connection to nature that needed to meet their ideal. He continued along this path by studying the life of Peter the Great with the intention of writing a novel for that time period. However he discontinued that exercise because of Peter the Great's introduction of Western values that Tolstoy saw as manifestations of the materialistic unnatural man. Personal rather than historical events would influence Tolstoy's after publication of War and Peace and Anna Karenina. His conversion from state mandated religion to personal, moral religious beliefs affected the writing for the rest of his life.
Going along with the realistic nature of his writing, Tolstoy exposes his rationalistic tendencies. His powers of observation resemble the scientific orientation of rationalism. The publication of The Cossacks was delayed for a number of years while the move toward reform of the system of serfdom was under consideration. Here again the emphasis on the natural man to whom the serfs were related caused great concern and debate and therefore the delayed publication of the book. Aside from his writing Tolstoy proposed radical reforms including the creation of schools for serfs where the students would dictate the direction of their education rather than the standard direction of the teachers mandating the direction of…
Cite This Term Paper:
"Literature Russian" (2002, March 07) Retrieved August 20, 2017, from
"Literature Russian" 07 March 2002. Web.20 August. 2017. <>
"Literature Russian", 07 March 2002, Accessed.20 August. 2017,
|
<urn:uuid:28f7707c-af98-4aa7-8dad-95fc098d2619>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.90625,
"fasttext_score": 0.052126288414001465,
"language": "en",
"language_score": 0.9719133973121643,
"url": "https://www.paperdue.com/essay/literature-russian-127931"
}
|
Breaking News
What is a pterygium?*
Trinidad Express / Pterygium (pronounced tery-gium) is a pinkish, fleshy growth from the conjunctiva (thin membrane covering the inside of the lids and white of the eye) extending on to the cornea (the clear front window of the eye). It usually presents on the side of the eye near the nose (nasal) but occasionally involves the outer (temporal) side. It may involve one eye or both and in few cases present with both nasal and temporal (double) pterygia in the same eye. A pterygium grows slowly towards the centre of the cornea and, if left untreated, may obstruct vision when it blocks light entering the pupil. It may also affect vision by distorting the regular shape, causing astigmatism) of the cornea. Causes of pterygium: These growths are believed to be caused by dryness, exposure to wind, atmospheric pollution, dust and ultra-violet (UV) light. They are commoner in hot, dry, sunny climates like Trinidad and Tobago. Some cases occur in families. Symptoms: A pink growth, burning, irritation, watering, redness and itching may occur.
About the author /
Related Posts
North America
Latin America
|
<urn:uuid:f5e24dc9-4784-481b-8165-b7c828eb0cc3>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.75,
"fasttext_score": 0.02272796630859375,
"language": "en",
"language_score": 0.8766229152679443,
"url": "http://mundinews.com/what-is-a-pterygium/"
}
|
Rhyme in Othello
Most of the language in Othello is unrhymed, either in the form of prose or blank verse. In certain passages, however, Shakespeare uses end rhyme to heighten the rhetorical pitch of the scene. The first four acts end on a rhymed couplet from Iago, who uses the lines to divulge the next stage of his unfolding plan. Other uses of rhyme include a satirical, blazon-style poem by Iago and several intense declarations from Othello.
Rhyme Examples in Othello:
Act I - Scene II 1
"For if such actions may have passage free, Bond-slaves and pagans shall our statesmen be...." (Act I - Scene II)
It is not clear whether Brabantio actually believes that Othello has committed a crime, or whether he is just threatened on a personal level. Nonetheless, Brabantio frames his condemnation of Othello as a broader act of justice. It is notable that Brabantio ends his lines, and the scene as well, with a rhyming couplet, a departure from the usual blank verse of the play. Shakespeare often uses this technique to end a scene or speech with emphasis.
"I have't. It is engender'd. Hell and night Must bring this monstrous birth to the world's light...." (Act I - Scene III)
Iago ends Act I with a strange, dense rhyming couplet. In these two lines, Iago layers three separate metaphors to describe his plot. The three metaphors are initiated in the first line and completed in the second. The first metaphor uses a cycle of conception—or engenderment—and birth. The second uses a movement from hell, or the underworld, up to the living world. The third uses the transition from night to day. One could say that the use of “monstrous” is aptly metaphorical as well. After all, the mythological definition of monster—a composite creature—finds its parallel in the “double knavery” of Iago’s plan.
"If virtue no delighted beauty lack,(310) Your son-in-law is far more fair than black...." (Act I - Scene III)
The Duke continues his pattern of issuing words of wisdom in the form of rhyming couplets. Using “black” as a double entendre to signify both virtue and race, he characterizes Othello as a virtuous man, no matter his race.
"To mourn a mischief that is past and gone Is the next way to draw new mischief on...." (Act I - Scene III)
The Duke takes on a scholarly tone here, speaking in rhyming couplets, each one of which serves as a wise saying. For the rest of his speech, the Duke invents new ways to tell Brabantio to get past his woes.
"the bloody book of law You shall yourself read in the bitter letter After your own sense...." (Act I - Scene III)
The Duke of Venice grants Brabantio the role of judge, jury and executioner. Shakespeare crafts these lines to be delivered dramatically. Notice the heavy alliteration and rhyme in phrases such as “bloody book of law” and “bitter letter.”
"If she be fair and wise, fairness and wit, The one's for use, the other useth it...." (Act II - Scene I)
Iago’s praise for Desdemona comes down to her combination of “fairness and wit”—her beauty and intelligence. As he puts it, beauty is a resource meant to be used by one’s wit. The rhyming couplets Iago uses to praise Desdemona underscore the irreverence and frivolity of his words.
"Why, how now, ho! from whence ariseth this?..." (Act II - Scene III)
Othello takes control of the scene with a commanding, eloquent speech. The musicality of his phrasing marks a change in tone from the brawl to the aftermath. He employs a number of subtle rhymes and alliterations: “turn’d Turks”; “barbarous brawl”; “holds his soul”; “dreadful bell”; “matter, masters.”
"If drink rock not his cradle...." (Act II - Scene III)
Shakespeare uses a combination of consonance and assonance to give this phrase emphasis. The pair of r and k sounds in “drink” are repeated in “rock.” This is an example of rim rhyme, a technique in which the beginning and ending sounds of a word are repeated in another. “Rock” shares its short o sound with “not,” creating a short rhyming chain. The phrase is additionally startling because of the trio of stressed syllables in “drink rock not.” These effects are purposeful; we get the sense of a cradle being rocked.
"“And let me the canakin clink, clink; And let me the canakin clink:..." (Act II - Scene III)
Shakespeare pens this tune using onomatopoeia, a technique in which the sounds of the words imitate their subject. In this case the words “canakin”—a drinking can—and “clink” recreate the sounds of cups and cans clinking together in a toast.
"Think every bearded fellow that's but yoked May draw with you. There's millions now alive That nightly lie in those unproper beds Which they dare swear peculiar...." (Act IV - Scene I)
Iago attempts to calm Othello by saying how common jealousy is. Iago uses the metaphor of a team of oxen to describe the shared plight of suspicious husbands together drawing the heavy plough of jealousy. Shakespeare assembles a sonorous trio of rhyming words in “dare swear peculiar.”
"Strumpet, I come! Forth of my heart those charms, thine eyes, are blotted; Thy bed, lust-stain'd shall with lust's blood be spotted...." (Act V - Scene I)
In a rhyming couplet, Othello addresses Desdemona from afar. He claims that her hold on him, represented by her eyes, has been “blotted,” or removed. The second line is highly ironic. While Othello plans to spill Desdemona’s lustful blood on their bed, the sheets are already stained with her matrimonial blood—the symbol of her faithfulness.
|
<urn:uuid:04e4ce95-31d0-4da6-a5f2-3eeccaf2d760>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.6875,
"fasttext_score": 0.10957175493240356,
"language": "en",
"language_score": 0.9239917993545532,
"url": "https://www.owleyes.org/text/othello/analysis/rhyme"
}
|
Presentation is loading. Please wait.
Presentation is loading. Please wait.
Similar presentations
Presentation on theme: "Bienvenidos a Nicaragua. MODERN TIMES ARCHITECTURE & LANDMARKS GEOGRAPHYGASTRONOMY HISTORY CULTURE & FAMOUS PEOPLE Table of Contents."— Presentation transcript:
1 Bienvenidos a Nicaragua
3 Pre-Columbian Period Present-day Nicaragua is located south of Mexico and northern Central America. When the Spanish arrived in western Nicaragua in the early 1500s, they found three major tribes, each with a different culture and language: the Niquirano, the Chorotegano, and the Chontal. Each one of these different groups occupied much of Nicaragua's territory, with independent chieftains (called cacicazgos) who ruled according to each group's laws and customs. As the Spanish conquered Central America, they settled along the west and highlands, wiping out the native population almost completely with the spread of new diseases and enslavement. In the east, where the Europeans didn’t settle, most of the indigenous groups survived. The English did, hoevever, introduce guns and ammunition to the Bawihka, who lived in northeast Nicaragua.
4 The People Each one of these diverse groups occupied much of Nicaragua's territory, with independent chieftains who ruled according to each group's laws and customs. – Occupying the territory between Lago de Nicaragua and the Pacific Coast, the Niquirano were governed by chief Nicarao, or Nicaragua, a rich ruler who lived in now the city of Rivas – The Chorotegano lived in the central region of Nicaragua – The Chontal (the term means foreigner) lived in the central mountain region. This group was smaller than the other two, and it is not known when they first settled in Nicaragua – These two groups had a lot contact with the Spanish conquerors, paving the way for the racial mix of native and European stock now known as mestizos
5 Niquirano Chorotegano Chontal
6 González then went further into an area governed by the cheif Nicaragua, or Nicarao. Chief Nicaragua welcomed González and gave him large quantities of gold. Thus begins Spanish rule in the new territory of Nicaragua. Nicaragua's Caribbean coast was first seen by Spanish explorers in 1508. In 1522 a formal military expedition under Gil González Dávila was led into Nicaraguan territory. After suffering sickness and dangerous weather, he reached the land ruled by the powerful chief Nicoya.They became friends and soon thereafter, Nicoya and 6,000 of his people were converted to Roman Catholicism. Throughout the seventeenth century, The local government of Nicaragua neglected agricultural production.Powerful earthquakes in 1648, 1651, and 1663, caused massive destruction in the country. From 1651 to 1689, Nicaragua was attacked viciously from English, French, and Dutch pirates, whom destroyed the city of Granada, Nicaragua’s center of agricultural wealth. The Captaincy General of Guatemala ruled the province at that time, and little was done to solve the problem. In 1687 the English governor of Jamaica named a miskito who was one of his prisoners "King of the Mosquitia Nation," and declared a region of Nicaragua to be under the protection of the English crown. This event was the beginning of a long rivalry between Spanish and British authorities over control of the Caribbean coast until the end of the nineteenth century. 1500’S 1600’S
7 Nicaragua is located in the middle of Central America, bordering both the Caribbean Sea and the North Pacific Ocean, right between Costa Rica and Honduras. The Caribbean coast extends with plain areas rising up to the central interior mountains. Climate is tropical in the lowlands near Managua, cooler in the highlands. Natural resources of Nicaragua are gold, silver, copper, tungsten, lead, zinc, timber, and fish. Near the city of Rivas is a coastal plain with many volcanoes.
8 Gastronomy Click on a dish to see its recipe
9 Boil the beef in 3 liters of water in a large cooking pot. Cut one bell pepper and one onion into large slices and place them, along with six garlic cloves, in the pot. After the beef is tender and completely cooked, remove it from the pot, and after letting it cool, shred it into small pieces. Heat the vegetable oil in a large, deep cooking pan. Cut one onion and two peppers into crescent-shaped slices and place them, along with the shredded beef, into the cooking pan. Add salt to taste and stir-fry at medium heat until golden brown. Strain the beef stock and place it in another large cooking pot. Add the achiote and cornflour or tortilla mix to the beef stock, and after placing it under a medium flame, add the yerbabuena. Stir the ingredients into a dough-like consistency. Blend the five remaining bell peppers, the tomatoes, and the rest of the garlic cloves well in a blender. Mix the contents of the blender into the dough and stir well. Add the beef stir fry and the naranja agria juice to the dough and continue blending at low heat. - 12 ounces of cornflour mix - 5 tomatoes - 3 large yellow onions - 1/2 teaspoon of black pepper - 1 cup of orange & lime juice - 1 bunch of mint To Prepare Ingredients -2 tablespoons of achiote - 2 1/2 pounds of lean beef - 8 large green bell peppers - 12 garlic cloves - 1/4 cup of vegetable oil - salt to taste - 4 ripe sweet plantains
10 Melt the butter in a skillet and brown the bananas very quickly over high heat. Place half the banana slices on the bottom of a buttered pie plate. Blend heavy cream and cream cheese until very soft. Add sugar, cinnamon, vanilla, and liqueur, beating until light and smooth. Spread half of the mixture over the bananas. Place remaining banana slices on top, and spread the rest of the cream-cheese mixture over the dish. Bake in a 375 degrees F. oven for 20 minutes or until almost all the cream is absorbed and the top is lightly browned. Do not allow all the cream to be absorbed, or the bananas will become too dry. Serve hot. If desired, top with whipped cream. Serves 6. Ingredients 4 tablespoons butter 6 firm bananas, peeled and sliced lengthwise 1 cup heavy cream 1/4 pound cream cheese 4 tablespoons granulated sugar 1 teaspoon cinnamon 1 teaspoon vanilla extract 1/2 cup Curacao liqueur To Prepare
11 Ingredients To Prepare Soak the beans in cold water overnight OR place beans in a small saucepan with 1 cup of water and cover. Bring to a boil and turn of heat. Allow to sit for 1 hour covered with the heat off. In a heavy skillet brown the oxtails in lard. Place them in a large (about 6 quart) stove top casserole or stock pot. Add all the remaining ingredients except the water and beans. Then, add just enough water to cover the contents of the pot, this should be about 2 cups more or less. Cover and simmer for 1 1⁄2 hours. Drain the beans and add to the stock pot. Continue cooking covered for an additional 1 1⁄2 hours. Stir occasionally and add additional water if necessary, you do not want the pot to dry out. If you like a thick stew, remove the lid during the last half hour of cooking. 1/3 cup uncooked white beans 1 tablespoon lard 3 pounds of beef oxtails 3 cloves of garlic, peeled and crushed 1 medium yellow onion, peeled and diced 1 medium tomato, diced 2 cups of beef stock 2 cups of water 2 tablespoons ground allspice salt and pepper to taste few shots of hot sauce
12 Ingredients To Prepare Preheat the oven to 375 degrees. To make the cake part, mix up 6 eggs, 1/2 cup of milk, 2 cups of flour, 1 1/2 teaspoons of baking powder, 2 cups of sugar and 3 tablespoons of vanilla. Make sure that it's all well mixed and then pour it into the cakepan and cook it for 20 minutes. The leches (milks) are supposed to be ready when the cake is done so you need to blend the 4 egg yolks, 1/2 cup of milk, 2 cans of condensed milk, and 2 cans of evaporated milk now. The baño (bath) is applied once the milks have been inserted. Heat up the corn syrup in a bowl while stiring it. Beat the 4 egg whites until they rise and pour in the syrup as you're whipping them. Get a spatula ready for applying the "bath" and start shredding the lemon peals with a cheese grater and add in cherry juice. Beat this mixture until it's well mixed. Once the cake is done, poke holes in it so that they milks can soak into it. Pour in the milks and lift up the sides and do whatever else you have to do to make sure that the cake is completely saturated with milk. Next cover the soaked cake with the "bath" and put it in the oven to cook for another 10 minutes at 400 degrees. Let it cook until the surface is done and then take it out. 6 eggs 4 egg yolks 4 egg whites 1/2 cup of milk 2 cups of flour 1 1/2 teaspoons of baking powder 3 1/2 cups of sugar 3 tablespoons of vanilla 2 cans of condensed milk 2 cans of evaporated milk 1 pint of whipped cream 1 1/2 cups of corn syrup 1 sour lemon
13 Managua Granada Cathedral of the Immaculate Conception (the new cathedral) Monument to the Revolution Government House Granada’s Central Square Granada Park A Government Building
14 From a population of 109,352 in 1950, the Capital of Managua reached 662,000 by 1980. By 1993 it had reached 1,600,666 people, more than one- third of Nicaragua’s entire population. The population could exceed 2 million by the start of the 21st century. Nicaragua’s population has grown rapidly in the past half century, as rural residents have migrated to the large cities of Managua & Granada, seeking a better life and safety from violence in the countryside. However, Nicaragua today is still struggling economically. Much of Managua’s downtown still lies in ruin since the earthquakes of 1931 & 1972. Though there are some affluent neighborhoods and middle-class areas. most of the city is occupied by very poor neighborhoods, without adequate water, sewers, and other services. These areas are constantly growing as thousands of poor people pour in from the countryside every year. Some have built makeshift houses of cardboard and tin in vacant lots of the former downtown area.
15 As of January 2002, the president has been Enrique Bolanos Geyer and the Vice President Jose Rizo Castellon. Members of the unicameral legislature and judicial branches are also elected. In order to vote in Nicaragua, you need to be 16 years of age. Jinotega Atlantico Norte Atlantico Sur Boaco Carazo Chinandega Chontales Esteli Granada Nicaragua’s Administrative Government is divided into 15 departments and 2 autonomous regions: Leon Madriz Managua Masaya Matagalpa Nueva Segovia Rio San Juan and Rivas Nicaragua is a republic. It gained it’s independence from Spanish rule on September 15, 1821. Executive power is held by the president, who is popularly elected for a five-year term.
16 However, Nicaragua is ranked as one of the poorest countries in the world, as about 50% of its population is under the poverty line. Agriculture employs about 45% of the workforce and counts for about one fourth of the gross national product. The chief commercial crops and exports are cotton, coffee, sugarcane,& meats. Timber, gold, and seafood are also exported. The principal manufactured goods are chemicals, textiles, and processed foods. The country's economy was severely affected by Hurricane Mitch in 1998. The Cordoba, Nicaragua’s currency
18 Rubén Darío (1867-1916), Nicaragua The founder of modernism, Rubén Darío is the most beloved poet of Latin American letters. His movement is "the Hispanic form of the universal crisis in literature and spirit that began around 1885". The dissolution of the 19th century, created an intellectual vacuum that manifested itself in art, science, religion and politics, as well as, gradually, in other aspects of life. Modernism in literature represented a deep historical change whose process continues today. Darío wrote Azul (Blue), 1888, Prosas Profanas (Profane Prose), 1896, and Cantos de Vida y Esperanza, 1905, the three works for which he became immortal.
19 Somoza
20 Chamorro
21 Art has been a treasured institution since revolutionary times. Here are a few examples Nicaragua’s artistic culture.
22 Credits
Similar presentations
Ads by Google
|
<urn:uuid:d9030b71-8efb-4c1c-bd6a-162c3df3a409>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.953125,
"fasttext_score": 0.03194725513458252,
"language": "en",
"language_score": 0.9293065667152405,
"url": "http://slideplayer.com/slide/4027141/"
}
|
2014 – Twitter
We use Twitter to collaborate with other schools around the world. Twitter is a program that lets you send instant messages (called tweets) using 140 characters or less to other ‘Twitterers.’
We have learnt:
* That it is okay to use ‘text’ talk and spelling in a tweet to save on characters. For example, you can spell ‘great’ as ‘gr8’ and ‘to’ as ‘2’.
* The tweet still needs to have a beginning, middle and end.
* Sometimes you can take out words to give you more characters and the tweet will still make sense.
* You need to address your tweet using ‘@’ if you are sending it to someone specific.
* It is really important to reread, revise and edit your tweets to make sure they make sense – just like you would for any other text.
Our first ‘Twitter’ project was with Mrs Monaghan and Class 2 (@class2middleham) in England and Mrs Yollis’ and her third graders (@YollisClass) in America. We tweeted clues for mystery numbers. Each class had a special day of the week that they tweeted the clues for the other two classes to try and work out the mystery number. When we tweeted our clues on Monday, Mrs Monaghan and Mrs Yollis and their classes were still enjoying their weekend. Whilst we were sleeping on Monday night, they replied to our tweets.
Our Mystery Number conversation
Capture 1
Capture 3
Tweeting mystery number clues helped us use and learn mathematical vocabulary. Some of the words we use are the same and some are different. We learnt what a ‘digital root’ is because we had to Google it to find out what Mrs Monaghan’s clues meant. To find the digital root you add the digits of a number together. For example, 234 has a digital root of 2+3+4 = 9
We also used Twitter to connect with Mrs S and 5/6CS in Tasmania for a weather tracking project. Mrs S set up a Google Docs spreadsheet for us to use to collect information about our weather. Some of our other blogging friends also joined in so we could compare weather from England, America, Darwin, Hobart and Melbourne.
Capture 2
Skip to toolbar
|
<urn:uuid:d6720615-52d5-48b4-82e1-f87fa9be1d3d>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.703125,
"fasttext_score": 0.17749017477035522,
"language": "en",
"language_score": 0.9131914377212524,
"url": "http://upps56team.global2.vic.edu.au/collaborative-projects/2014-twitter/"
}
|
This Land is Your Land, This Land is Whose Land?
The risky geographical charting expedition that forever affected Lake Tahoe resources
Reads 1765 Comments 1 Printer-friendly versionprint Send by emailemail
Ever wonder why Lake Tahoe is split down the middle, with one half in California and the other half in Nevada? Are the two states just that good at sharing? The history of the split dates back to the 1840s and the early explorers of the American West, when mapmakers were beginning to chart the unknown territory, and California joined the Union as a state.
Lieutenant John C. Frémont, an American military officer and later a candidate for the U.S. presidency, was tasked with the first of three government surveying expeditions in 1843, according to the Truckee-Donner Historical Society. His team spent nine months charting the Northwest before finally heading south and coming upon the friendly Paiute tribe that camped on the land by Pyramid Lake, the geographical sink of the Truckee River Basin that sits 71 miles northeast of Lake Tahoe. Sarah Winnemucca, granddaughter of the chief of the Paiute Tribe at the time, writes of the meeting in Life of Among the Piutes, “My grandfather met [Frémont], and they were soon friends … Captain Frémont gave my grandfather the name Captain Truckee, and he also called the river after him. Truckee is an Indian word, it means all right or very well.”
Frémont and his men had hoped the Paiutes would guide them to Mexican California, a Mexican Territory including much of modern day California, Nevada, and Utah, but as Scott Lankford describes in Tahoe Beneath The Surface, the tribe roared with laughter at the mere thought of crossing the Sierra Nevada Mountains during the winter. Yet, Frémont was persistent, and so Chief Truckee, although not volunteering to go on the trek, described in detail a route for them following the Truckee River to get to the Sierra Nevada where they would see a large mountain lake that fed Pyramid Lake, referring to Lake Tahoe or Donner Lake, according to Fremont’s “Discovery” of Lake Tahoe in 1844 by Mark Mclaughlin.
Frémont boldly headed southwest soon meeting the Washoe Tribe, who stressed that the men would likely die if they tried to cross the Sierra in winter. Pushing on, Frémont and his men trekked through waist-deep snow, with threats of snow blindness and starvation. Lankford describes that on February 14, 1844, Frémont and mapmaker Charles Preuss summited a peak to get a better view, and could see the outline of a giant mountain lake. After the epic trek, they couldn’t even enjoy the view! They ignored what Chief Truckee had said to them and instead assumed the large body of water must flow to the Pacific Ocean. The gorgeous lake did not spark much interest in either of the men, clearly delirious from their travels, and they continued on after marking it on the map, according to Mark McLaughlin.
Years later, in 1849, as Lankford describes, the battle over California entering the Union ensued, and if California were to enter as a pro-slavery state the careful balance in the U.S senate would tip in favor of the South. A budding politician, Frémont finagled the votes needed to redraw California state lines along the Eastern Sierra, thereby excluding a large portion comprising some of present-day Utah and Arizona. With the smaller Eastern Sierra boundary it was less likely that the state would break up and form a smaller division that was pro-slavery, according to John P. Wilusz in The Colorful History of The California/Nevada State Boundary. In the already heated debate it is hard to know exactly why the border was put where it was, as officials would surely want to keep the resource that is Lake Tahoe entirely in California. Lankford provides the theory that “innocent measurement error in Frémont’s California map placed Lake Tahoe further west … worse yet Frémont’s map erroneously showed a river flowing directly from Lake Tahoe to the Pacific Ocean by way of San Francisco Bay.” After Frémont manipulated the border along the Eastern Sierra, he most likely placed the state division too far west based on his initial measurement made on that seemingly unremarkable February day, making Lake Tahoe a forever-shared treasure between Nevada and California.
Reader comments so far...
Storm King | Carnelian Bay, CA
Just read the article on the Calif. - Nevada state line. In fact, the reason the boundary runs through Lake Tahoe (2/3 vs 1/3 - not half and half) is because delegates at California's 1849 Constitutional Convention - where they were drawing up the new state's principles (free or slave) as well as its physical borders - arbitrarily decided to run the eastern boundary along the 120 degree longitude until it reached the 39th parallel latitude where it then bears southeast to gain access to eastern Sierra resources as well as water from the Colorado River. Fremont was at the convention, but he too was fairly uninformed about the actual Pacific Divide which runs along the Sierra Crest and separates water from the Great Basin (Tahoe included) and water that will flow to the Pacific Ocean. This longitudinal boundary line started at 42 degrees latitude because that was the southern border of Oregon Territory. These delegates were completely unaware of the topographic nature of the terrain or watershed boundaries in the Sierra (the spelling "Sierras" is incorrect). This eastern boundary did jump around slightly until a telegraph line was put in which enabled Alexis Von Schmidt (Tahoe dam and Truckee River to S.F. aqueduct engineer) to access the exact time which is necessary to plot accurate longitudinal meridians. Latitude can be fairly well determined with a hand-held instrument. When Nevada held its own Constitutional Convention in the early 1860s, delegates wanted the border moved west to the Pacific Divide for a more equitable use of water rights based on watershed, but California was a powerful state that refused to give up what it had grabbed first. FYI. Although Lankford's book has interesting stories I would not use it as a exemplary reference as he does a lot of over-reaching and makes questionable assumptions in that publication. An editor with an historical/geographical background would have caught many of his errors. That's my opinion anyway. There are other questionable statements in your article, but I don't want to nitpick. Just thought you would like this additional info for clarification.
Don't Miss the Next Edition
Edition First-Round Deadline Drop-Dead Deadline
About News
Subscribe to the feed
Latest Tweets @moonshineink
Look for the latest Moonshine Ink issue on newsstands now.
Look for the latest issue in newsstands now.
August 10, 2017
|
<urn:uuid:9f0eddc2-84b2-47db-af7a-bc135fdac181>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.02217501401901245,
"language": "en",
"language_score": 0.9593285918235779,
"url": "http://www.moonshineink.com/news/land-your-land-land-whose-land"
}
|
Political History | About Ghana
On 6 March 1957, the British colony of Gold Coast became independent and assumed the name Ghana. Until 1957, the Gold Coast consisted of the Gold Coast colony which comprised British processions on the Gold Coast littoral and extended less than one hundred miles inland up to the Pra; Ashanti,
which included today’s Ashanti, Brong Ahafo and parts of Easter Region. A name Ghana was assumed at independence for three reasons. First, some of the founding fathers of Ghana argued that the Akan of the Gold Coast, who constituted 45% of the population were descendants of the ancient Ghana Empire that flourished from the 9th to the 13th Centuries between the Sahara and head waters of the Senegal and Niger rivers. Second, the spectacular example of ancient Ghana in building a great African empire that endured for three centuries was emulating by the emergent nation. Finally, the name was not ethnically specific to any of the countries numerous ethnic groups, it will therefore engender the spirit of national coercion and consciousness.
The total land area of Ghana is 238,538 square kilometres (92,100 square miles); the southern coast line being 554 kilometres (334 miles) wide and the distance from the south to the north being 840 kilometres (522 miles). Ghana is located on the Gulf of Guinea and boarded on north by Burkina Faso on the east by the Republic of Togo and on the West by Cote d’Ivoire.
Today, the population of Ghana is about 22 million with the highest population densities on the urban areas. The principal ethnic groups are the Akans who constitute about 45% of the population is made up of the Ashanti, the Fanti, the Ahanta, the Guan, the Bonu, the Akyem, the Akwamu, the Kwahu, the Akwapim, the Sefwi and the Nzema; the Mole, Dagbani, 16% is made up of Nanumba, Dagbani, Mamprusi, Wala, Bruilsa, Frafra, Talensi and Kusasi; the Ewe, 13% made up of the Anlo, the Some, the Tongu and the Ewedome; the Ga-Adangbe, 9% made up of the Ga, the Shai or Adamgbe, the Ada and the Krobo or the Kloli; the Gurma, 4% and the Grusi, 2% made up of the Mo, the Sisala, the Kasena, the Vagala and the Tampolene,. Living among the Ewe are non-Ewe speaking groups such as the Akpafu, the Lolobi, the Likpe, the Santrokofi, the Nkonya, the Avatime, the Logba and the Tafii.
The peoples of Ghana are composed of two principal linguistic groups: the Gur and the Kwa group of languages, which are respectively spoken to the north and south of the Gurma and the Grusi and the speakers of Kwa are the Akan, the Guan, the Ewe and the Ga-Adamgbe.
Political History
2015 - Despite Group
To Top
|
<urn:uuid:455aaeae-cdac-4093-b2a8-7878b85a8945>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.578125,
"fasttext_score": 0.10170841217041016,
"language": "en",
"language_score": 0.918738067150116,
"url": "http://ghana.peacefmonline.com/pages/about_ghana/political_history/"
}
|
vulcan club
, 1st century, AD, p.29.] This constellation is said to represent the Roman Hercules, Greek Herakles, who was the greatest of the Greek heroes and famous for his twelve labors.
As an infant Hercules strangled two serpents sent by Juno to kill him as he lay asleep in his cradle.
It is suggested that the two serpents represent the the Lunar Nodes.
He died on a funeral pyre, became a god, and ascended to Mount Olympus to join the other gods.
Engonasin is a Greek title for Hercules, with Roman writers translating it Geniculator or Geniculatus; these terms meaning 'the Kneeling Man'.
Engonasi, from , 'on his knees" [Valpy, p.136].
See this webpage on Roman Hercules, and this webpage on Greek Heracles, for the mythology associated with Hercules.
The name Hercules is from a Latin translation of Greek Herakles.
Herakles' name is translated 'the glory of Hera' or 'the fame of Hera', the prefix of his name relates to , variously translated; 'to listen', 'to hear oneself called', 'to be spoken of', 'called upon'.
The second element in Hercules' name comes from the Indo-European root *, to praise, tell), cliometrics (the systematic use of economic theory and econometric techniques to study economic history), Hercules (from Greek Herakles), sarod (a many-stringed lute of northern India that is played with a plectrum), Clovis (relating to a prehistoric human culture in North America from about 12,000 to 9,000 B. [see Wordnik] Heracles was the son of the god Zeus and a mortal woman, Alcmene, whom Zeus visited in the form of her husband, Amphitryon.
C., distinguished by sharp fluted projectile points made of chalcedony or obsidian). Early in life Herakles was called Alcaeus, or Alcides, after his mother Alcmene, the name Heracles came later.
Heracles comes from - in his name refers to Hera (Roman Juno), wife of Zeus (Roman Jupiter).
|
<urn:uuid:79990fe9-ba97-457b-9215-306af5d3e6ae>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.515625,
"fasttext_score": 0.14128869771957397,
"language": "en",
"language_score": 0.9465842843055725,
"url": "http://kdp.tomsk.ru/nv/vulcan-club-46"
}
|
The English Language Is An Optimist
A study finds that positive events outnumber negative events and that we therefore use far more positive words than negative words:
The researchers say we've adopted a number of habits of convenience that reflect the frequent use of positive words in our language (in turn reflecting the greater frequency of positivity in the world). For example, positive words tend to be 'unmarked' - that is, the positive is the default (e.g. 'happy') whereas the negative is achieved by adding a negating prefix (i.e. 'unhappy'). Rozin cites four more such habits. Here's one more: when stating pairs of good and bad words together, it's nearly always the convention to mention the positive word first: as in 'good and bad' and 'happy and sad' rather than the other way around.
|
<urn:uuid:fc9e050e-0b1a-42f9-882b-d9b856070316>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5,
"fasttext_score": 0.3896833658218384,
"language": "en",
"language_score": 0.878852367401123,
"url": "https://www.theatlantic.com/daily-dish/archive/2010/06/the-english-language-is-an-optimist/186208/"
}
|
What Kind of Weather Is Associated With Stratus Clouds?
What Kind of Weather Is Associated With Stratus Clouds?
••• Anne08/iStock/GettyImages
Stratus and cumulus clouds are the two primary types of cloud structure, with each producing different types of weather. Stratiform clouds, also called stratus clouds, themselves come in four varieties: cirrostratus, altostratus, stratus and nimbostratus. Some of these stratus clouds provide a strong indication of approaching precipitation, while others produce precipitation. Knowing how to read these cloud types can help identify the weather you will encounter.
Types of Clouds and Stratus Clouds Definition
There are four main types of clouds. These are called:
1. Cirroform
2. Cumuloform
3. Stratiform
4. Nimboform
The stratus clouds definition, aka stratiform clouds, are defined as "blanket" clouds. The name of these clouds is rooted in the word "strata" comes from the Latin word for "layer" because stratus clouds form blanket-like layers.
Stratiform clouds are usually wide and spread out across the sky like a blanket. Stratus cloud edges usually look thinner and diffuse outwards as you get closer to the edge of the cloud. They form as air rises and are usually around warm air fronts.
You can also find clouds that are "combinations" of different general cloud types, which will be gone over in detail here.
Cirrostratus Clouds
Cirrostratus clouds are a type of high-level clouds that occur above 18,000 feet. This type of stratus cloud consists of thin, sheetlike layers of white clouds. These clouds are comprised of ice crystals and produce no precipitation. However, cirrostratus clouds are a key meteorological predictor of the weather to come.
Widespread layers of cirrostratus clouds are typically the first visual indicator of an approaching front. As such, they can signal the possibility of rain or snow within 24 hours when followed by mid-level cloud formation.
Altostratus Clouds
Altostratus clouds are a type of mid-level cloud, occurring between 6,000 and 18,000 feet. These clouds typically develop behind cirrostratus clouds, indicating the approach of a storm front and the potential for widespread, continuous rain. Altostratus clouds typically cover the entire sky, extending over large areas. These types of stratus clouds rarely produce any precipitation.
Stratus Clouds
Stratus clouds are a type of low-level cloud, occurring below 6,000 feet. They are characterized by uniform layers of grayish clouds. Stratus cloud layers are generally thin but cover the entire sky, known as overcast. Stratus clouds are formed by weak, gentle upward air currents that lift large layers of air high enough to produce condensation.
However, the overall atmosphere remains too stable to produce cumulus clouds, which require dynamic vertical instability. Stratus clouds appear like fog that does not reach the ground. Stratus clouds are capable of producing light mist or an occasional light drizzle. If the stratus clouds begin to produce consistent precipitation, they are reclassified as nimbostratus.
Nimbostratus Clouds
Nimbostratus clouds are a type of low-level cloud, occurring below 6,000 feet. They are similar to stratus clouds, except they are actively producing stratus clouds precipitation. This precipitation is typically consists of light to moderate rain or snow, which is continuous in nature. This low-intensity precipitation can last for several hours or several days.
Because they form in conditions unfavorable to vertical development, nimbostratus clouds never produce heavy rains or thunderstorms. Nimbostratus clouds are associated with warm fronts, where warm, moist air gradually overrides colder air at the surface. Visibility is very low beneath nimbostratus clouds. One of the reasons for this lack of visibility is steady precipitation.
However, a secondary cause is the formation of fog and scud, resulting from precipitation-cooled air below the cloud layer. Scud, also known as stratus fractus or fractostratus, is low, fast-moving fragments of clouds below the main cloud deck.
Related Articles
What Kind of Cloud Types Have Precipitation?
What Type of Clouds Are Rain Clouds?
What Kind of Weather Do Nimbostratus Clouds Cause?
What Makes Rain Clouds Dark?
What Are Some Interesting Facts about Stratus Clouds?
What Type of Clouds Make Tornadoes?
Description of the Different Types of Clouds
Warning Signs of Thunderstorms
Warm Front Characteristics
What Is the Difference Between Cumulus Clouds & Cirrus...
Rain Clouds Vs. Snow Clouds
6 Steps on How Clouds Are Formed
Facts on Cirrostratus Clouds
Warning Signs of Storms
What Clouds Are Associated With a Cold Front?
Kinds of Precipitation
The Characteristics of Stable Air Mass
How Does a Cyclone Affect the Weather?
The Three Types of Weather Fronts
Different Kinds of Weather Conditions
Dont Go!
We Have More Great Sciencing Articles!
|
<urn:uuid:ebe4a0e2-2202-4b44-a598-b46de59b9470>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.734375,
"fasttext_score": 0.36441361904144287,
"language": "en",
"language_score": 0.8852240443229675,
"url": "https://sciencing.com/kind-weather-associated-stratus-clouds-8434178.html"
}
|
What is brachytherapy?
Brachytherapy is a treatment that places sealed radioactive sources inside the patient temporarily or permanently to damage the DNA of the cancer cells and destroy their reproductive capacity, division and growth. Brachytherapy allows the oncologist to use a high dose of radiation to treat an area in less time than conventional radiation therapy. It can be used to treat various cancers located throughout the body.
Why is brachytherapy done?
Brachytherapy is a class of radiation therapy used to treat cancer. It uses ionising radiation to kill cancer cells and shrink tumours.
It is used to treat cancers throughout the body, including:
What does brachytherapy consist of?
Brachytherapy can be temporary or permanent:
• Temporary brachytherapy: In this type of brachytherapy, a highly radioactive material is inserted within a catheter for a specific time, and then removed. It can be administered in low or high doses.
• Permanent brachytherapy: This is also known as seed implantation since radioactive ‘seeds’ or ‘granules’ are inserted into the tumour or close to it, and are left there permanently. After a few months, the radioactivity level decreases until the ‘seeds’ become inactive. The inactive seeds remain inside the body, without any effect on the patient.
Preparation for brachytherapy
Experts in oncology and radiotherapy will determine the necessary preparation prior to brachytherapy, which may include ultrasound or MRI scans, blood tests, electrocardiograms or chest X-rays, amongst others.
Care after brachytherapy
After brachytherapy, although the radioactivity of the seeds (in the case of permanent brachytherapy) decays rapidly, there are certain recommendations to limit close contact with others, especially children and pregnant women.
After brachytherapy, the patient may notice sensitivity and swelling in the treated area. However, patients can return to their work activities within days or weeks of the intervention.
The doctor will recommend follow-up sessions which are important to determine if the patient’s health condition is stable or has undergone changes. This will also allow the doctor to see if the patient has experienced any possible side effects.
|
<urn:uuid:574c6e13-1a9c-44ff-8979-cd9e6e31fb0f>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.875,
"fasttext_score": 0.28812992572784424,
"language": "en",
"language_score": 0.9115979075431824,
"url": "https://www.topdoctors.co.uk/medical-dictionary/brachytherapy"
}
|
One of the main tenets of the scientific method; repeating an experiment to ensure that the results can be attained again. May use an exact duplicate of an experiment or an alternative procedure, or completely different techniques may be used to try to gather theoretical information. See also: balanced replication.
REPLICATION: "Replication helps to ensure that an outcome for an experiment is not a fluke."
Cite this page: N., Sam M.S., "REPLICATION," in, April 28, 2013, (accessed October 22, 2021).
|
<urn:uuid:82e7835f-42a0-4860-ac84-74f3f5084fbc>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.734375,
"fasttext_score": 0.603359043598175,
"language": "en",
"language_score": 0.9063487648963928,
"url": "https://psychologydictionary.org/replication/"
}
|
TOEFL Reading Practice 4
Please take a moment to complete this quiz.
Read the following passage and answer the question
In context, which word most closely defines mélange?
TOEFL Test Information
The TOEFL (Test of English as a Foreign Language) Exam is intended to measure a student’s ability to understand and use English at a college level. Over 6,000 colleges, government organizations, and businesses accept TOEFL test scores worldwide. The TOEFL Test serves a similar function to other standardized tests (such as SAT and ACT Tests) in that they used by colleges and universities as a factor in admissions.
Different institutions place varying degrees of importance on standardized tests, such as the TOEFL, and use them along with other factors such as GPA, class rank, community service, recommendations and extracurricular activities.
The TOEFL test is given in two formats: Internet-based (iBT) or paper-based (PBT). The TOEFL iBT has 4 test sections: reading, listening, speaking, and writing. The TOEFL iBT takes about four and a half hours to complete. The TOEFL paper-based test is being phased out. Currently, over 96% of TOEFL tests are taken via the internet.
For more help, review our free TOEFL practice tests.
Some questions are from the following sources:
Erik Jacobsen at www.erikthered.com/tutor
CK-12 Foundation - www.ck12.org
About Test-Guide
Follow us
|
<urn:uuid:303e1223-e84e-4d71-9640-562d772dc8b1>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.609375,
"fasttext_score": 0.21035438776016235,
"language": "en",
"language_score": 0.9238294363021851,
"url": "https://www.test-guide.com/toefl/free-toefl-practice-tests/toefl-reading-practice-4.html"
}
|
Sports Performance: Hydration
You are to create a poster or other similar visual to meet the outcomes related to hydration (Outcome 2) in HSS1020 and 3.6 evaluate snacks and meal plans based on the goal of achieving optimal nutrition within various context.
Step 1: Think of four people for this project: a child, such as a younger sibling; a teenager, such as yourself; a middle-aged adult, such as a parent; and a senior, such as a grandparent. Research the signs and symptoms of dehydration, both while at rest and while physically active, for each of these people.
Step 2: Outline a strategy for each person to prevent dehydration both while at rest and when physically active. Include strategies to replace sugary, caffeinated, alcoholic, or other beverages as the case may be.
Step 3: Prepare a visual demonstration to showcase your strategy and findings.
Mr. McIntosh
Teacher - Humanities
No Comments Yet
Comments are closed
|
<urn:uuid:e0b9a67d-c681-4f9c-85db-1ed3895256c8>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.9375,
"fasttext_score": 0.7150951623916626,
"language": "en",
"language_score": 0.9394297003746033,
"url": "https://kylemcintosh.ca/sports-performance-hydration/"
}
|
Gas Explosions: How They Happen
Natural gas explosions occur when leaking gas accumulates in an enclosed area and ignites. Gas that combines with air above ground, below ground or in any type of conduit can form a highly volatile mixture; when the concentration reaches 5 to 15 percent and an ignition source is present, an explosion can occur.
Take all reports of gas leaks seriously, and take immediate action to identify the source of the leak and eliminate ignition hazards.
|
<urn:uuid:696e6497-7609-4c90-a5ad-4812b82c77ba>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.625,
"fasttext_score": 0.08640694618225098,
"language": "en",
"language_score": 0.8654871582984924,
"url": "https://lge-ku.e-smartresponders.com/topic/gas-explosions-how-gas-explosions-happen/"
}
|
Kōrero: Extinctions
Monitoring kākāpō (1 o 2)
Monitoring kākāpō
Kākāpō are unique, ground-dwelling parrots that were once widespread in New Zealand. With the introduction of predators such as rats, ferrets and cats, the species was heading rapidly towards extinction. In 2006 there were only 86 remaining birds, all on predator-free islands in southern New Zealand.
This photograph, taken in the early 1980s, shows a radio transmitter being attached to a kākāpō named Tawbert, so he could be tracked for several years. Tawbert was one of the last known kākāpō in Fiordland, where none have been seen since 1987.
Te whakamahi i tēnei tūemi
Department of Conservation
Reference: 10058005
Ngā whakaahua me ngā rauemi katoa o tēnei kōrero
Te tuhi tohutoro mō tēnei whārangi:
Richard Holdaway, 'Extinctions - New Zealand extinctions since human arrival', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/mi/photograph/13662/monitoring-kakapo (accessed 22 October 2021)
|
<urn:uuid:93948246-72fb-487b-9160-d1e10af5793c>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.03822517395019531,
"language": "en",
"language_score": 0.9128349423408508,
"url": "https://admin.teara.govt.nz/mi/photograph/13662/monitoring-kakapo"
}
|
Often asked: What Was The Main Historical Event Described In Ezra And Nehemiah?
What happened between Ezra and Nehemiah?
What event does the book of Ezra detail?
Book of Ezra covers the events of the Jews returning from the Babylonian captivity. Near 520 BC after the takeover by Nebuchadnezzar, ultimately King Cyrus of Persia arose to power, and he decided to aid the Jews to return to Jerusalem. The Jews are counted and are permitted to return to Judah to rebuild the Temple.
You might be interested: Quick Answer: What Was Nehemiah Chapter One Vs One And Two About?
What is the main theme of the book of Ezra?
What is Ezra known for?
What can we learn from the book of Ezra?
What is the point of Nehemiah?
What is the difference between Ezra and Nehemiah?
You might be interested: Readers ask: What Do Passages Like Ezra 3:12-13 And Nehemiah 11:1-2 Suggest About Life In Post-exilic Jerusalem?
What books of the Bible did Ezra write?
The canonical Book of Ezra and Book of Nehemiah are the oldest sources for the activity of Ezra, whereas many of the other books ascribed to Ezra (First Esdras, 3–6 Ezra) are later literary works dependent on the canonical books of Ezra and Nehemiah. The book of Ezra–Nehemiah was always written as one scroll.
Did Ezra write the Old Testament?
What period of time is covered in the Books of Ezra Nehemiah and Esther?
What period of time is covered in the books of Ezra, Nehemiah, and Esther? 538-458 B.C.
Which tribe of Israel were the priests?
What caused Nehemiah to pray and fast for four months?
You might be interested: Readers ask: Unfortunately, There Were Some Important Leaders In Tekoa Who Would Not Help Nehemiah Do The Work.?
Can Ezra be a girl name?
Who is the father of Ezra in Bible?
Ezra (active 5th century B.C.) was a Hebrew priest, scribe, religious leader, and reformer who vitally influenced Judaism. The son of Seraiah, Ezra was a descendant of the ancient priestly house of Zadok.
Leave a Reply
|
<urn:uuid:0cb98c7a-2a6c-4ae2-b925-551421c08f0c>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.6302165985107422,
"language": "en",
"language_score": 0.9606125950813293,
"url": "https://nehemiahlv.org/nehemiah/often-asked-what-was-the-main-historical-event-described-in-ezra-and-nehemiah.html"
}
|
All About Puffins!
10. Like Clockwork
Every spring and summer, puffins return to land so that they may breed and create even more pufflings! They return each year with the same mate since they’re the loyal type that mates for life.
9. Burrows
Instead of nests, puffins like to create burrows or use old rabbit holes to lay their eggs in. It isn’t uncommon for them to continue to use the same burrow or hole each year.
8. Auk
Isn’t that a fun word, “auk”? Puffins are members of the Auk family and aren’t very big in size. Most only reach up to 11 inches high as adults.
7. Life Span
Believe it or not, puffins live an average of 20 years in the wild! In captivity they have been known to live for up to 36 years, or at least, that’s the age of the longest-lived puffin in captivity.
6. Main Threats
Gulls aren’t the only threat that puffins face. Other giant threats to their population include pollution, such as oil spills – since they live the majority of their life in the sea, and overfishing. Oil spills are especially dangerous since it damages their otherwise waterproof feathers that are essential for them to live.
5. Food for Thought
The primary food for puffins is the sand eel, which is basically a small, soft little fish. If nothing else, they can also capture and eat herring.
4. Bad News
Since the sand eel is a puffin’s primary source of food, it might be bad news for them that the sand eel population seems to be reducing in numbers. It has caused some puffins to try feeding their babies alternate foods such as pipe fish, but this can cause the babies to choke as they’re too hard.
3. Not Yet in Danger
Thankfully, puffins aren’t quite in danger yet, as they’re willing to travel very long distances in order to find the food they need to survive. Even so, their numbers have also fallen rather dramatically in each country that they are found in.
2. Are They Related to Penguins?
You’d be surprised how many people think to ask this! Although they share the same familiar black and white color scheme, puffins are not related to penguins. Puffins are auks, and Penguins are not auks.
1. Pufflings
When pufflings are first born, they spend the first 45 days of their lives being attended to by their loving parents – who as we said before, abandon them after this time. After that, they spend 3-5 years at sea learning how to do what puffins do before finally returning back to land.
Please enter your comment!
Please enter your name here
|
<urn:uuid:b584aa45-a2bc-4adb-a0cd-019855fcee7b>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.578125,
"fasttext_score": 0.0490686297416687,
"language": "en",
"language_score": 0.931629478931427,
"url": "https://thefuzzypuffin.com/2018/07/30/all-about-puffins/2/"
}
|
Enter the average value of Q1 and Q3, and the interquartile range into the calculator to determine the low and high outliers.
Outlier Formula
The following equation can be used to calculate the values of the outliers.
L = Q1 – (1.5* IQR)
H = Q3 + (1.5*IQR)
• Where L is the lower outlier
• H is the higher outlier
• Q1 and Q3 are the average values of those quartiles
• IQR is the interquartile range
Outlier Definition
An outlier is defined as the extreme values of a set of data that vary the most from the mean or norm.
What is an outlier?
An outlier is a term used in statistics to describe extreme values that vary from the norm of a data set. In other words, the highest and lowest values of a data set that sit apart from the rest.
What causes outliers?
Outliers occur either by chance or by measurement error.
How many outliers are there?
There can be any number of outliers, but often times the outliers can be the sample maximum and minimums as the formula above calculates.
outlier calculator
outlier formula
|
<urn:uuid:6cf952dc-d9ff-448d-99b1-d2edcb9bc914>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 4.0625,
"fasttext_score": 0.7196934223175049,
"language": "en",
"language_score": 0.8632946610450745,
"url": "https://calculator.academy/outlier-calculator/"
}
|
Frequent question: How did the Bantu migration impact agriculture in Africa?
Introduction of iron working: they introduced iron-working and the use of iron tools throughout much of Africa, and when iron-smelting started, there was an increase in food production. Introduction of new crops e.g. yams, bananas: the Bantu increased their knowledge of food and crop cultivation.
How did the Bantu migrations influence Africa?
In central Africa, the spread of Bantu-speaking people had effects on the environment. Introducing new crops and farming techniques altered the natural landscape. Raising cattle also displaced wild animal species. Agriculture improved the ability of Bantu-speakers to reproduce and expand more quickly.
What was the impact of the Bantu migrations on Sub Saharan Africa?
During the thousands of years of Bantu migration, a variety of crops, livestock, agricultural technologies (especially iron farming tools) spread in sub-Saharan Africa, greatly promoting the development of agriculture in sub-Saharan Africa.
IT IS INTERESTING: Is there tax on Cryptocurrency in South Africa?
What were the most important effects of the Bantu migration?
The principal consequences of the Bantu migration, then, may be summarised as: the spread of the Bantu and Bantu-related languages. the spread of iron-smelting and smithing technology. the spread of pottery techniques.
What was the Bantu migration and how did it change Africa?
Effects of the Bantu Migration
Before the expansion of farming and pastoralist African peoples, Southern Africa was populated by hunter-gatherers and earlier pastoralists. The Bantu expansion first introduced Bantu peoples to Central, Southern, and Southeast Africa, regions they had previously been absent from.
What skills did the Bantu spread through Africa?
Bantu-speakers in West Africa moved into new areas in very small groups, usually just families. But they brought with them the Bantu technology and language package—iron, crops, cattle, pottery, and more. These pioneers then shared their more advanced technologies (and, in the process, their languages) with the locals.
Why were the Bantu migrations important in African history?
why are the Bantu migration an important part of the African history? The Bantu migration was important because of the knowledge of metalworking, iron tools gave them more control over the environment, and lastly they learned different skills.
What were three effects of the Bantu migrations?
The effects of the Bantu Migration were the spread of the Bantu language, culture, agricultural practices, and metalworking skills all across…
What were the causes and effects of the Bantu Migration?
Epidemics, diseases and natural disasters: The Bantu moved due to natural disasters (earthquakes, flooding of rivers like river Niger), sickness, and diseases such as Nagana caused by Tsetse flies. 6. Search for fertile land: The Bantu migrated to find fertile land suitable for agriculture.
IT IS INTERESTING: When did tea reach Africa?
How did migrations impact Africa focus on the causes and effects of each?
The Bantu Migrations affected Africa in many ways. … They also spread their farming skills and as they migrated they spread iron technology which changed many farming techniques in sub-Saharan Africa. They also introduced sophisticated industries which had a great impact on Africa.
What was a major reason why the Bantu speaking peoples migrated?
The reasons for the Bantu migrations are unknown to many, but they most likely include these listed below: Drying up of the Sahara grasslands which led groups that practiced agriculture to migrate in search of new fertile land and water for farming. (Drought and Famine)
What are the causes of Bantu migration?
Causes of Bantu migrations
• Overpopulation.
• exhaustion of local resources – agricultural land, grazing lands, forests, and water sources.
• increased competition for local resources.
• a spirit of adventure.
• tribal rivalries or family conflicts.
• climate change and other natural calamities affecting crops.
• famine.
• epidemics.
What are the major causes of migration?
4 Major Causes of Migration in India
• Marriage: Marriage is a very important social factor of migration. …
• Employment: ADVERTISEMENTS: …
• Education: …
• Lack of Security:
Hot cold Africa
|
<urn:uuid:3953c03a-f43e-4c41-9aeb-c07c8dfb0c0f>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.671875,
"fasttext_score": 0.8006356358528137,
"language": "en",
"language_score": 0.943337082862854,
"url": "https://inkaba.org/about-africa/frequent-question-how-did-the-bantu-migration-impact-agriculture-in-africa.html"
}
|
전문 고주파 회로 기 판,고속 회로 기 판,IC 패 키 징 기 판,반도체 테스트 판,HDI 회로 기 판,소프트 하 드 결합 판,양면 다 층 판,PCB 디자인 및 PCBA 제조
믿 을 만 한 PCB 회로 제조 업 체!! Contact Us
Manufacturing technology of PCB printed circuit board
Author：ipcb Share
Introduction: PCB is the abbreviation of printed circuit board in English. In general, in the insulation material, according to pre-set, made into printed circuit, printed components or a combination of the two conductive graphics known as printed circuit. And in the insulating substrate to provide electrical bonding between components of the conductive graphics, known as printed circuit. So the printed circuit or printed circuit board is called printed circuit board, also known as printed circuit board or printed circuit.
Production technology of PCB printed circuit board
Almost all the facilities we can see from PCB are inseparable from it, ranging from watches, calculators and general-purpose computers on electronic wrists to computers, communications, and military weapon systems. As long as there are no electronic components such as integrated circuits, PCB is needed for their electrical interconnection. It provides mechanical support for various fixed assembly of integrated circuits, successfully realizes wiring and electrical connection or insulation between various electronic components such as integrated circuits, and supplies special electrical properties required, such as special property impedance, etc. At the same time, it provides solder mask graphics for semi-automatic soldering, and provides error identification characters and graphics for component insertion, inspection and maintenance.
PCB printed circuit board
How is PCB made?
When we open the keyboard of a general-purpose computer, we can see a piece of soft film (flexible insulating substrate), printed with silver color (silver paste) conductive pattern and healthy position pattern. Because of the general screen leakage method to obtain this pattern, we call this kind of printed circuit board as flexible silver paste printed circuit board.
And we go to the computer city to see a variety of computer motherboards, video cards, sound cards and home appliances on the printed circuit board is not the same. The base material is made of paper (usually used on one side) or glass cloth (usually used on both sides and multi layers), pre impregnated with phenolic resin or natural epoxy resin, and then laminated and solidified with copper sheet on one or both sides of the surface layer. This kind of circuit board is covered with copper sheet material, we call it rigid board.
Then made into printed circuit board, we call it rigid printed circuit board. One side has printed circuit graphics, we call it single-sided printed circuit board, two-sided printed circuit graphics, and then through the metallization of holes, the implementation of double-sided interconnection formed printed circuit board, we call it double-sided board. If a printed circuit board with two sides as the inner layer, two single sides as the outer layer or two double sides as the inner layer and two single sides as the outer layer, the printed circuit board which is alternately connected by the positioning system and insulating bonding materials and the conductive patterns are interconnected according to the preset requirements, will become a four layer or six layer printed circuit board, also known as multilayer printed circuit board.
Today, there are more than 100 layers of practical printed circuit boards.
PCB production process is more complex, it involves a wide range of processes, simple methods to deal with single machining to complex machining, there are ordinary chemical reactions, photochemistry, electrochemistry, thermochemistry and other processes, computer aided preset cam and other aspects of knowledge.
And in the production process, there are many process problems and new problems will be encountered from time to time, and the local problems will disappear without finding out the end cause. Because the production process is a non continuous way of plane contact line, no matter what link is wrong, it will lead to the whole line production or large quantity of waste. If the printed circuit board is scrapped by karma, there is no way to recycle it.
Therefore, many engineers left the industry and turned to PCB facilities or material suppliers to do sales and technical services.
Production technology of PCB printed circuit board
In order to advance our understanding of PCB, we have to understand the manufacturing process of general single-sided and ordinary multilayer board, and increase the depth of understanding of it.
Single side rigid printed circuit board: → single side copper clad laminate → blanking → (scrubbing and drying) → drilling or punching → screen printing circuit anti-corrosion pattern or using dry film → curing, checking and repairing board → etching copper → removing anti-corrosion printing material, drying → scrubbing and drying → screen printing solder mask (commonly used green oil), UV curing → screen printing character mark graphics, UV curing → preheating, punching and shape → electrical opening and short circuit Road test → scrubbing and drying → pre coating of welding aid anti oxygen gasifier (drying) or tin spraying hot air leveling → inspection and inspection of packaging → delivery of finished products.
Double sided rigid PCB:
Double sided copper clad laminate → blanking → lamination → digital control drilling through hole → inspection, deburring and scrubbing → electroless plating (through-hole metallization) → (plating thin copper on the whole board) → inspection and cleaning → screen printing negative circuit graphics, curing (dry film or wet film, exposure, development) → inspection and inspection, plate repair → circuit graphics electroplating → tin plating (anti-corrosion nickel / gold) → printing material (sense) Light film) → etch copper → (tin stripping) → cleaning and scrubbing → screen printing solder mask, commonly used heat curing green oil (paste photosensitive dry film or wet film, exposure, development, heat curing, commonly used photosensitive heat curing green oil) → cleaning, drying → screen printing character graphics, curing → (tin spraying or organic solder coating) → appearance processing → cleaning and drying → electrical on-off inspection and measurement → inspection and inspection of package Loading → finished products leaving the factory.
Through hole metallization process flow of multi-layer laminate production → double side cutting of inner layer copper clad laminate → scrubbing → drilling positioning hole → sticking photoresist dry film or coating photoresist → exposure → development → etching and film removal → inner coarsening and deoxidization → inner layer investigation → (outer layer single-sided copper clad laminate circuit manufacturing, b-step bonding sheet, plate bonding sheet checking, positioning hole drilling) → lamination → digital Control drilling → hole inspection → pre hole disposal and electroless copper plating → thin copper plating on the whole board → coating investigation → sticking light resistant electroplating dry film or coating photoresist plating agent → surface layer and bottom plate exposure → development and repair board → circuit graphic electroplating → tin lead alloy or nickel / gold plating → film removal and etching → search and arrest → screen printing solder mask or photo solder mask → printed character graphics → (hot air leveling or Organic solder film) → digital control washing shape → cleaning and drying → electrical on-off inspection and determination → finished product inspection → packaging and delivery.
It can be seen from the process flow chart that the multi-layer plate technology is developed from the foundation of double face metallization process. In addition to the double-sided process, it also has several unique and special internal significance: interconnection of metallized holes, drilling and deoxidizing oxygen drilling, positioning system, lamination and special materials.
Our common computer boards are basically double-sided printed circuit boards based on epoxy resin glass cloth. There are plug-in components on one side and the soldering surface of component pins on the other side. It can be seen that the solder joints are very regular. The component pins of these solder joints have separate welding surfaces, so we call them pads. Why are other copper wire patterns not tin coated. Due to the need for tin solder pad and other parts, the remaining part of the surface has a layer of wave soldering resistance film. Most of the solder mask on its surface is green color, and a small amount of them are suitable to use yellow, black, blue, etc. Therefore, solder resist oil is often called green oil in PCB industry. The utility of this method is to avoid bridge phenomenon in wave welding, increase welding quality and save solder equivalent. It is also a long-term PCB care layer, can play a moisture-proof, anti-corrosion, mildew and mechanical scratch equivalent. From the outside, the appearance of the bright green color solder mask, film on the plate photosensitive heat curing green oil. Therefore, the appearance of the solder pad is not very accurate.
Exterior mounting technology has the following advantages:
(1) Because of the large number of printed circuit boards, the interconnection technology of large through-hole or buried hole is eliminated, the wiring density on the printed board is increased, the size of printed board plane or object surface is reduced (generally one third of plug-in installation), and the preset layer number and cost of printed circuit board can be reduced.
(2) It has slowed down the weight, increased the seismic performance, considered appropriate and used glue solder, thought of new welding technology, increased the quality and reliability.
(3) Because of the increase of wiring density and the reduction of lead length, the parasitic capacitance and inductance are reduced, which is more helpful to increase the electrical parameters of PCB.
(4) Compared with plug-in installation, it is easier to realize semi-automation successfully, increase installation speed and labor productivity, and reduce assembly cost accordingly.
It can be seen from the above appearance safety technology that the growth of PCB technology is growing with the growth of chip packaging technology and surface mounting technology. Now we look at the computer board, its surface adhesion rate is constantly rising. In fact, this kind of circuit board and transmission screen printing circuit graphics is no way to meet the technical requirements. Therefore, the normal high and very accurate circuit board, its circuit graphics and solder mask patterns are basically considered appropriate, and the use of photosensitive circuit and photosensitive green oil manufacturing process.
With the development of high density PCB, the requirement of PCB production is higher and higher. More and more new technologies are applied to PCB production, such as laser technology, photosensitive natural resin, etc. The above is only a superficial introduction. There are many items in PCB production that are not explained clearly due to space limitation, such as blind buried hole, flexible board, Teflon board, lithography technology, etc. If we want to deepen the discussion, we should try our best.
|
<urn:uuid:6469a627-320d-4404-a98b-87d9721d7389>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.6875,
"fasttext_score": 0.11253595352172852,
"language": "en",
"language_score": 0.9211467504501343,
"url": "https://www.ipcb.kr/tech/250.html"
}
|
James Watt
Biography of James Watt
James Watt
James Watt
The University's Engineering Building is named for James Watt (1736-1819), who worked from 1756 to 1764 as mathematical instrument maker to the University. Two Engineering chairs and a prize are also named for him.
Watt spent the following years developing his invention and working as a consultant civil engineer in Scotland, before moving to Birmingham in 1774 to form a partnership with the industrialist Matthew Boulton (1728-1809) at his Soho Foundry. Their improved steam engines revolutionised the mining, iron, transport and manufacturing industries and Watt is considered to be one of the key figures of the Industrial Revolution. In 1806 the University conferred on him a Doctorate of Laws.
A statue of James Watt can be found on the SW corner of George Square in Glasgow City centre. More information about the statue can be found here.
James Watt embodied the values and achievements of the Enlightenment and the Industrial Revolution. However, the Enlightenment’s celebration of human progress, reason and scientific knowledge developed in countries that held people in slavery, and the Enlightenment provided ideological justifications for slavery based on a belief in the hierarchy of races. Some Enlightenment figures owned enslaved people or saw little or no problem with slavery. In 1757, for example, the American inventor Benjamin Franklin (who like Watt was a member of Birmingham’s famed Lunar Society) brought an enslaved man and boy with him to London, both of them Franklin’s property.
Watt’s great scientific and engineering achievements are rightly celebrated. But it is also true that his family profited through the trade in slave-produced goods (such as sugar, rum and cotton from Antigua and other Caribbean islands) and on occasion they were actively involved in the purchase and sale of enslaved people. In March 1762, for example, Watt’s brother John arranged for the shipment of a young boy, who was quite likely enslaved, from the Caribbean to Glasgow.
In later years, Watt undoubtedly made money by producing machinery for businesses in the Caribbean which owned enslaved people. On the other hand, during the Haitian revolution in 1791, Watt is on record cancelling an order placed by a French form for a steam engine intended for the colony of Saint Domingo (now Haiti). Watt writes: "We sincerely condole with the unhappy sufferers, though we heartily pray that the system of slavery so disgraceful to humanity were abolished by prudent though progressive measures."
We cannot celebrate the achievements of James Watt and other great men and women of the Enlightenment without remembering their society’s complicity in race slavery and imperialism, and without acknowledging that our present-day experience and understanding of race developed out of the attempts of Enlightenment thinkers to address the basic contradiction between professing liberty and upholding slavery.
James Watt
Engineer and Inventor
Born 19 January 1736.
Died 25 August 1819.
University Link: Honorary Graduate
GU Degree: LLD, 1806;
Occupation categories: engineers; instrument makers
NNAF Reference: GB/NNAF/P29937
View Major Archive Collection Record
Search for this person in the DNB
Record last updated: 26th Aug 2019
University Connections
University Roles
• Honorary Graduate
Academic Posts
On This Day Entries
There are no comments available.
|
<urn:uuid:2d860014-81cc-4374-a54d-5f4d8d83ba98>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.018306851387023926,
"language": "en",
"language_score": 0.9626837968826294,
"url": "https://www.universitystory.gla.ac.uk/biography/?id=WH0018&type=P&o=&start=0&max=20&l="
}
|
Who Led South Korea During The Korean War?
Who was the leader of South Korea at the outbreak of the Korean War?
In the south, the anti- communist dictator Syngman Rhee (1875-1965) enjoyed the reluctant support of the American government; in the north, the communist dictator Kim Il Sung (1912-1994) enjoyed the slightly more enthusiastic support of the Soviets.
Who led the invasion of South Korea?
Did South Korea win the Korean War?
The war began on 25 June 1950 when North Korea invaded South Korea following clashes along the border and insurrections in the south. The war ended unofficially on 27 July 1953 in an armistice.
You might be interested: Often asked: Why Do People Wear Masks In Korea?
Who led South Korea in 1950?
How was the United States involved in the Korean War? Prior to Kim Il-Sung’s Soviet-backed invasion in 1950, the United States military was involved in rebuilding Korea south of the 38th parallel and training a standing South Korean army.
What caused the outbreak of the Korean War?
The Korean War (1950-1953) began when the North Korean Communist army crossed the 38th Parallel and invaded non-Communist South Korea. As Kim Il-sung’s North Korean army, armed with Soviet tanks, quickly overran South Korea, the United States came to South Korea’s aid.
Why did US lose Korean War?
The USA did not lose the Korean War. The goal was containment of Communist expansion, not the conquest of North Korea, which the would have resulted in a full scale war with the Chinese. Legally there was no War because Congress did not declare war – it was a United Nation’s Police Action.
Why did America invade Korea?
Fearing that the Soviet Union intended to “export” communism to other nations, America centered its foreign policy on the “containment” of communism, both at home and abroad. Indeed, Asia proved to be the site of the first major battle waged in the name of containment: the Korean War.
Who was to blame for the Korean War?
For most historians it was the Russians that were responsible for the outbreak of the Korean War, perhaps wanting to test Truman’s determination. Stalin had supplied the North Koreans with tanks and other equipment. Moreover Kim Il Sung could not have acted without Stalin’s go-ahead.
You might be interested: Often asked: How To Be An Actress In Korea?
Why North Korea and South Korea are separated?
The United States supported the South, the Soviet Union supported the North, and each government claimed sovereignty over the whole Korean peninsula. In 1950, after years of mutual hostilities, North Korea invaded South Korea in an attempt to re-unify the peninsula under its communist rule.
Who really won the Korean War?
After three years of a bloody and frustrating war, the United States, the People’s Republic of China, North Korea, and South Korea agree to an armistice, bringing the fighting of the Korean War to an end. The armistice ended America’s first experiment with the Cold War concept of “limited war.”
Who won Vietnamese war?
Opposition to the war in the United States bitterly divided Americans, even after President Richard Nixon ordered the withdrawal of U.S. forces in 1973. Communist forces ended the war by seizing control of South Vietnam in 1975, and the country was unified as the Socialist Republic of Vietnam the following year.
Which side won in Korean War?
Who Won the Korean War? Neither side actually won the Korean War. In fact, the war goes on to this day, since the combatants never signed a peace treaty. South Korea did not even sign the Armistice agreement of July 27, 1953, and North Korea repudiated the armistice in 2013.
Why did North Korea invaded South Korea in 1950?
This conflict began on June 25, 1950, when North Korea, a communist nation, invaded South Korea. By invading South Korea, North Korea hoped to reunite the two nations as a single country under communism. With North Korea’s invasion of South Korea, the United States feared the spread of communism.
You might be interested: Readers ask: Why Does North Korea Hate The Us?
What religion is in South Korea?
South Korea is a country where all the world’s major religions, Christianity, Buddhism, Confucianism, and Islam, peacefully coexist with shamanism. According to the 2015 statistics, 44% of South Koreans identified with a religion.
When did Korea become a democracy?
Thus it was, in 1948, constitutional democracy was introduced, after 1987, procedurally it became consolidated.
Leave a Reply
|
<urn:uuid:6472f58a-6f29-4bf1-ac55-78fddbfee325>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.734375,
"fasttext_score": 0.895302414894104,
"language": "en",
"language_score": 0.9465396404266357,
"url": "https://www.herxtravels.com/korea/who-led-south-korea-during-the-korean-war.html"
}
|
The President of the United States is one of the most heavily criticized positions in the world, and often the weight of their decisions affects the lives of millions of people. Although criticism of the president is necessary, the president is often subjected to both reasonable and unreasonable criticism. Undoubtedly, this can become an albatross for presidents as their administrations are judged the American people.
An undeniable truth, though, is that there are only six living people who understand what it is like to hold this position. As a result, the ability of citizens to develop informed critiques of presidential administrations requires that they have the abilities both to analyze critical evidence and use that evidence to develop a sense of historical empathy with decision-makers during high-stakes moments.
These high-stakes moments – the times when presidents finds themselves in the “hot seat” – can often shape or change the course of a presidency in periods as short as 24 hours. As teachers, we must enable student citizens to make informed critiques of presidents in high-stakes moments as to better help them understand the position of President of the United States. Within this website, educators will find primary sources and lessons plans that place students in the role of these decision-makers during intense situations such as the attack on Pearl Harbor, the Cuban missile crisis, 9/11, and many more.
Scroll to top
|
<urn:uuid:6dbd2923-dd39-4199-87d3-82b53a3a2917>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 4.0625,
"fasttext_score": 0.09088706970214844,
"language": "en",
"language_score": 0.9694069027900696,
"url": "http://presidentialhotseat.org/overview/"
}
|
The Baroque: Art in an Age of Crisis
The late 16th century was a time of crisis and conflict, and change echoed across Europe and its empires. Religious reform, scientific discovery, and political upheaval shook the foundations of early modern society. Yet from this turbulent time, an era of extraordinary artistic achievement emerged, defined by a dynamic new visual language. This course will examine how "the Baroque" became a global language, from its early beginnings in Rome to Spain, France, Flanders and the Dutch Republic, even extending beyond the borders of Europe to Asia and the Americas. In addition to studying leading artists such as Caravaggio, Bernini, Rubens, Vermeer and Velázquez, important themes to be considered will include space and spectacle in urban planning; the mundane and profane in still life and genre; collections and curios; the church triumphant; and the portrait. Prerequisite: Intro to Western Art (L01 113).
Course Attributes: FA AH; EN H; BU Hum; BU IS; AS HUM; AS LCD; GF AH; FA HUM; AR HUM
Section 01
The Baroque: Art in an Age of Crisis
View Course Listing - SP2022
|
<urn:uuid:6b276ec7-2bd2-4425-b0c0-8590d12f49d4>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.53125,
"fasttext_score": 0.02492576837539673,
"language": "en",
"language_score": 0.8923788666725159,
"url": "https://arthistory.wustl.edu/baroque-art-age-crisis"
}
|
Αγγλική Γλώσσα (Γυμνάσιο)
Κατεβάστε σε μορφή PDF
3 ώρες
Young Indianas, R U ready to explore?
45 λεπτά
Artful Thinking
Φύλλα Εργασίας
Activity 0: Warm up (10 minutes)
Show the ppt about the British Museum and the Parthenon Marbles to connect students with their previous knowledge from their book and as a lead in activity for the following activities .
Slide1-2 : View of the outside of the British Museum to identify it
Slide 3-4: Portrait of Lord Elgin to identify him and discuss what he is famous for.
Slide 5: Photos of reconstuction of the East and West Pediment . Photo of Marbles from the East Pediment in the British Museum. Identify where the marbles are taken from.
Activity 1 : Group formation (5 minutes)
Materials needed:
On the 3 tables that had been ready for the students before they entered the classroom put a copy of an ancient Greek statuette, an Egyptian papyrus and an object reminding Roman times (e.g. an antique cuff bracelet). Ask the students to move next to the object they feel aesthetically or emotionally closer to, in order to form their groups according to their preferences or emotional reactions to the objects.
Activity 2: (30 minutes) (20 minutes preparation – 10 minutes presentation)
Materials needed: 3 PCs, internet connection, worksheets, envelopes.
The worksheets had been placed in the envelopes on the desk of every team, according to the piece of art they have chosen and are waiting for the teams to open them. Let us not forget, they are secret missions. In the worksheets there are detailed instructions as to how they will navigate the site of the museum and learn to find their way in it as the info they are looking for.
Team A, students who have chosen the papyrus, set off for Mission 2 exploring the exhibit “A party” and the theme of “Dress and Ornament in Ancient Egypt”.
Team B, students who have chosen the statuette, set off for Mission 4 exploring the exhibit “A Caryatid” and the theme of “Dress and Ornament in Ancient Greece”.
Team C, students who have chosen the item of jewelry, set off for Mission 6 exploring the exhibit “ The Juliana Bracelet” and the theme of “Dress and Ornament in Roman Britain”.
Ask them to follow the instructions of the worksheet carefully, in order to find their way in the site of the Museum. Remind them to look at the exhibits closely and think about the questions asked in Part A of the worksheet where they are asked to emotionally respond and express their feelings through language . Remind them to take down notes. After all they are archaeologists and they must come to conclusions after their observation. Ask them to appoint a representative for the presentation of the team’s thoughts and feelings in class.
warm up presentation
Initiate discussion to connect to the following activity
The Party
Museum Exhibit for mission 2 Group A
A Cariatid
Museum Exhibit for mission 4 Group B
The Juliana Bracelet
Museum Exhibit for mission 6 Group C
Δημιουργός Σεναρίου: ΑΘΗΝΑ ΧΑΡΑΛΑΜΠΙΔΟΥ (Εκπαιδευτικός)
|
<urn:uuid:d569d1d9-434e-440f-83a9-4fbe47a00ef6>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.05362933874130249,
"language": "en",
"language_score": 0.8606406450271606,
"url": "http://aesop.iep.edu.gr/node/22894/5796"
}
|
Cog (ship)
A cog is a type of ship that first appeared in the 10th century, and was widely used from around the 12th century on. Cogs were clinker-built, generally of oak, which was an abundant timber in the Baltic region of Prussia. This vessel was fitted with a single mast and a square-rigged single sail. These vessels were mostly associated with seagoing trade in medieval Europe, especially the Hanseatic League, particularly in the Baltic Sea region. They ranged from about 15 to 25 meters (49 to 82 ft) in length with a beam of 5 to 8 meters (16 to 26 ft), and the largest cog ships could carry up to about 200 tons.[1]
Cogs were a type of round ship,[2] characterized by a flush-laid flat bottom at midships but gradually shifted to overlapped strakes near the posts. They had full lapstrake, or clinker, planking covering the sides, generally starting from the bilge strakes, and double-clenched iron nails for plank fastenings. The keel, or keelplank, was only slightly thicker than the adjacent garboards and had no rabbet. Both stem and stern posts were straight and rather long, and connected to the keelplank through intermediate pieces called hooks. The lower plank hoods terminated in rabbets in the hooks and posts, but upper hoods were nailed to the exterior faces of the posts. Caulking was generally tarred moss that was inserted into curved grooves, covered with wooden laths, and secured by metal staples called sintels. Finally, the cog-built structure could not be completed without a stern-mounted hanging central rudder, which was a unique northern development.[3] Cogs used to have open hulls and could be rowed short distances. In the 13th century they received decks.
Cogs are first mentioned in 948 AD, in Muiden near Amsterdam. These early cogs were influenced by the Norse knarr, which was the main trade vessel in northern Europe at the time, and probably used a steering oar, as there is nothing to suggest a stern rudder in northern Europe until about 1240.[4]
The need for spacious and relatively inexpensive ships led to the development of the first workhorse of the Hanseatic League, the cog. The new and improved cog was no longer a simple Frisian coaster but a sturdy seagoing trader, which could cross even the most dangerous passages. Fore and stern castles would be added for defense against pirates, or to enable use of these vessels as warships, such as used at the Battle of Sluys. The stern castle also afforded more cargo space below by keeping the crew and tiller up, out of the way.
The most famous cog still in existence today is the Bremen cog, depicted at the left. It dates from the 1380s and was found in 1962; until then, cogs had only been known from medieval documents and seals.
In 1990, well-preserved remains of a Hanseatic cog were discovered in the estuary sediment of the Pärnu River in Estonia.[6] The Pärnu Cog has been dated to 1300.[6]
In 2012, a cog preserved from the keel up to the decks in the silt was discovered alongside two smaller vessels in the river IJssel in the city of Kampen, in the Netherlands.[7] The ship, dating from the early 15th century, was suspected to have been deliberately sunk into the river to influence its current. Consequently, little was expected to be found in the wreck, but during excavation and recovery in February 2016, an intact brick dome oven and glazed tiles were found in the galley as well as a number of other artifacts about the vessel.[8][9]
See also
1. "Hamburg Museum - Medieval Hamburg (4) - The Cog - A Cargo-carrying Vessel of the Middle dixious Ages". Retrieved 5 April 2013.
2. "Round ship". Oxford Reference. Oxford University Press. Archived from the original on 15 September 2017. Retrieved 14 September 2017.
3. Crumlin-Pedersen, Ole (October 2000). "To be or not to be a cog: the Bremen Cog in perspective". International Journal of Nautical Archaeology. 29 (2): 230–246. doi:10.1111/j.1095-9270.2000.tb01454.x.
4. Åkesson, Per (January 1999). "The Cog". Archived from the original on 26 March 2016. Retrieved 14 September 2017.
5. Gardiner, Robert; Unger, Richard W., eds. (August 1994). Cogs, Caravels and Galleons: The Sailing Ship, 1000-1650. Conway's History of the Ship. London: Conway Maritime Press. ISBN 978-0-85177-560-9.
6. Õun, Mati and Hanno Ojalo. 2015. 101 Eesti laeva. Tallinn, Kirjastus Varrak, page 12.
7. "Excavation, recovery and conservation of a 15th century Cog from the river IJssel near Kampen". Ruimte voor de Rivier IJsseldelta. Rijkswaterstaat. September 2015. Archived from the original on 6 July 2017. Retrieved 14 September 2017.
8. Ghose, Tia (17 February 2016). "Medieval Shipwreck Hauled from the Deep". Live Science. Archived from the original on 7 July 2017. Retrieved 14 September 2017.
9. "Late Medieval Cog from Kampen". Medieval Histories. 21 February 2016. Archived from the original on 14 September 2017. Retrieved 14 September 2017.
|
<urn:uuid:5974af24-f1f4-46b9-aee9-218c671b734b>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.71875,
"fasttext_score": 0.022113382816314697,
"language": "en",
"language_score": 0.9580458402633667,
"url": "https://zims-en.kiwix.campusafrica.gos.orange.com/wikipedia_en_all_nopic/A/Cog_(ship)"
}
|
43,000-Year-Old Musical Instruments Found
New dating methods have pushed back the dates of previously found musical instruments, figurative art, and mythical imagery. This makes them the oldest yet found.
These human-created objects found in Geißenklösterle Cave in southwest Germany have been dated using new methods designed to remove contamination. The new dating methods have produced ages between 42,000 to 43,000 years old.
These dates push back the starting date of the “Aurignacian period.” The Aurignacian culture is one of oldest cultures to have left artifacts such as figurative art, musical instruments, personal ornaments, and mythical imagery.
These dates are older than the Aurignacian dates found in France, Italy, England, and other areas. This supports the Danube corridor hypothesis, which says that “modern” humans first migrated through the Danube drainage. With later migrations forming the majority of modern European DNA. Most modern Europeans would be much more closely related to later Middle Eastern immigrants from around 10,000 years ago than to these earlier Europeans.
20120527-015555.jpg Geißenklösterle Cave is one of several caves in the Swabian Jura to have produced important examples of these artifacts.
These new dates suggest that modern humans entered the Upper Danube region prior to an extremely cold climatic phase referred to as the H4 event around 40,000 years ago. Previously, it had been a matter of argument among researchers whether humans came before or after this event.
Now, it looks as though the first modern humans entered southwestern Germany during a mild phase of the last ice age, under conditions where they could have had contact with Neanderthals. But, so far, no evidence of cultural contact between the two has been found in that area.
These dates point to the Upper Danube Valley as the possible homeland of the Aurignacian culture. The Swabian caves contain the earliest records of the technology and art that are characteristic of the Aurignacian.
The central focus of new research in this area is resolving whether these technological innovations were in response to climatic stress, conflict with the stronger and larger-brained Neanderthals, or other social-cultural dynamics such as slave-keeping.
Source: Universität Tübingen
Image Credits: Württembergisches Landesmuseum Stuttgart, Universität Tübingen
Leave a Reply
|
<urn:uuid:25a5e661-d3f7-45d0-8177-64b899229d02>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5625,
"fasttext_score": 0.09679853916168213,
"language": "en",
"language_score": 0.9337255358695984,
"url": "https://planetsave.com/2012/05/27/43000-year-old-musical-instruments-found/"
}
|
When Blue Planet turns into Blueberry Planet
God bless science – thanks to Anders Sandberg, a computational neuroscientist at the University of Oxford’s Future of Humanity Institute we now know what would happened if the ball of space rock we call our home was replaced by an equal sized ball of blueberries. And it’s muffin to laugh about:
Sandberg’s paper aims to answer the question, “What if the entire Earth was instantaneously replaced with an equal volume of closely packed, but uncompressed blueberries?” In doing so, Sandberg makes a key assumption: The Earth turns into “big, thick-skinned highbush blueberries” and not “wild, thin-skinned blueberries.”
That turns out to be a big deal: The bigger, thick-skinned blueberries would have a lot more space between them when Earth spontaneously transformed into the evenly spaced blueberry pile. And, in Sandberg’s model, that space would be filled with air — air that would start doing some very interesting things very quickly…
Perched on a mushy ground of free-rolling blueberries, you might notice a sensation in your gut like an elevator dropping as your weight dropped by 87 percent, Sandberg wrote. If you weigh 150 lbs. (68 kilograms) on normal Earth, you’d weigh about 20 lbs. (9 kg) on the far-less-dense blueberry planet, Sandberg said in the paper.
That soft, messy, low-gravity blueberry surface might be a fun place to hang out if it lasted. But, Sandberg said, things would start to change — fast.
All that air trapped between the blueberries would rush to the surface as the blueberry pile started to collapse into itself under its own gravitational pressure. Huge bubbles would burst from the surface, flinging matter into space even as the interior of the planet coalesced into a thick blueberry jam.
The effect of the geysers of bubbles combined with the collapsing planetary core would be “the worst earthquake ever,” Sandberg wrote. “And it keeps on going until everything has fallen [towards the center of the planet] 715 km [444 miles]. While this is going on, everything heats up drastically [by about 143 degrees along the Celsius scale or 258 degrees along the Fahrenheit scale, thanks to the gravitational energy release] until the entire environment is boiling jam and steam. The result is a world that has a steam atmosphere covering an ocean of jam on top of warm blueberry granita.”
Aren’t you glad you asked?
Related: What if the moon was really made of cheese?
|
<urn:uuid:4f8800ef-b417-4603-bb65-04c905684ad8>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5625,
"fasttext_score": 0.13030171394348145,
"language": "en",
"language_score": 0.9366090297698975,
"url": "http://thedailychrenk.com/2018/08/06/blue-planet-turns-blueberry-planet/"
}
|
The Archaeology of North Carolina
North Carolina Archaeological Regions
Southern Piedmont region
Archaeology of the Southern Piedmont
During the Paleo-Indian, Archaic, and Early and Middle Woodland periods, archaeology of the southern Piedmont is much like the rest of the Piedmont. However, the southern Piedmont region is archaeologically unique within North Carolina during Late Woodland times. After A.D. 1000 the cultures located between the Uwharrie Mountains and the South Carolina border did not participate in the Piedmont Village Tradition. Instead they were influenced by the South Appalachian Mississippian Tradition.
The Paleo-Indian is the time of the earliest generally accepted arrival of people in the southeastern United States - between 9000 and 10,000 B.C
Paleo-Indian Chronology in North Carolina
Archaeologists working in the Southeast use radiocarbon dating and differences in spear point forms and frequencies to tell time during the Paleo-Indian Period.
Paleo-Indian Settlement and Subsistence in North Carolina
Paleo-Indian settlers in the Southeast found a rapidly changing landscape. Current evidence suggests that many of extinctions of Late Pleistocene megafauna - including the horse, mastadon, and mammoth - were complete by 8500 B.C.
Piedmont Paleo-Indian
When Paleo-Indians first came into the Piedmont winters were harsher and summers cooler than today. For about 1000 years, both people and now-extinct Pleistocene animals co-existed in North Carolina.
The Archaic Period (8000 - 1000 B.C.) covers over half of the timespan people have lived in North Carolina. This vast time has been explored by finding well-preserved deposits in rock-shelters and stratified, deeply-buried open sites.
The Archaic Period in the Piedmont
As in the preceding Paleo-Indian period, much more is known about the Archaic in the Piedmont than either the mountains or the coastal areas. In North Carolina, archaeologists were able to define long chronological sequences by excavating deeply buried, stratified sites in the alluvial floodplains of the Piedmont
In North Carolina, the Woodland is divided into Early, Middle, and Late periods. Along the coast and through much of the Piedmont, the Late Woodland continues until the Contact period, while in the Appalachian Summit and in the Southern Piedmont, Mississippian and Mississippian-influenced societies developed after A.D. 1000.
Piedmont Tradition Early and Middle Woodland Periods (1000 B.C. - A.D. 800)
The Badin and Yadkin phases begin the Piedmont Village Tradition across the Piedmont.
Southern Piedmont Late Woodland Period
The Late Woodland across the Piedmont begins with a continuation of the Piedmont Village Tradition Late Woodland Uwharrie phase. But in the southern Piedmont the Late Woodland villages typical of the rest of the Piedmont were not present after A.D. 1000. Rather, the southern Piedmont saw the arrival of the Pee Dee culture - mound builders with a stratified and politically complex society.
The time of contact between Indians living in North Carolina and Europeans arriving from Spain and England varied considerably across the state. Beginnings of these arrivals do not necessarily herald the beginnings of significant changes in the histories of North Carolina's tribes. However, overall, this was a time of sweeping and often devastating change.
Contact, Interaction, and Cultural Change in the Piedmont
A sufficient number of contact period sites in the Piedmont have been excavated to allow an overview of the specific consequences of the interaction between tribes and Euro-Americans. Although these effects were certainly felt in the southern Piedmont, the contact period is better known in the north central Piedmont, the central Piedmont, north into Virginia, and southeast towards the colonial center of Charleston.
North Carolina today is the home of the largest Native American population east of the Mississippi River. The robust cultural diversity seen in the archaeological record of the last 12,000 years survives today in the tribal traditions of North Carolina's native peoples.
©2010 UNC-RLA
|
<urn:uuid:fe13c801-6eb9-47eb-ac76-b2d59a3008ad>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.78125,
"fasttext_score": 0.09689629077911377,
"language": "en",
"language_score": 0.9286170601844788,
"url": "http://rla.unc.edu/ArchaeoNC/SPiedmont.htm"
}
|
How Benin City Wall became a UNESCO World Heritage Site
Benin city walls, known as “benin gates” by some African countries, are an ancient cultural heritage site in the northern part of Africa.
The walls are built from a solid block of limestone that is made of the mineral calcite.
The limestone blocks are typically used as a foundation for the walls, which are made of several layers of different rock, making the walls of a single building.
Benin’s city walls were built by a nomadic group of nomadic tribes known as the Djambi.
The Djambis are the most powerful people in the area, having ruled the area since at least the 15th century.
When the city walls of Benin were first discovered in 2010, they were considered by many archaeologists to be the oldest city walls in the world.
This is because the site dates back to before the dawn of civilization, meaning the Djemba and the Benin are one in the same.
The city walls are the largest known examples of building on an area larger than a football field, making them a rare example of large-scale, continuous stone construction.
These are some of the largest and most complex stone walls in Africa.
They are often referred to as “Benin City Walls” because of the name they bear.
The most significant features of the Benoian City Walls are the central gate of the city, which is the main entrance to the city.
The center of the gate is an impressive four-story building, which was completed around 12,000 years ago.
The building is also one of the most important sites in the entire city of Beno.
A total of five gates are located in the city center, which includes the central gates, the main gate, the eastern gate, and the western gate.
This area has been a site of religious and political activity for the Benonians for more than 2,000 to 3,000 generations.
Some scholars believe that the gate was constructed to serve as a religious center.
Another important feature of the City Walls is the monumental and ornate architecture that has been constructed around them.
The central and eastern gates of the central wall were constructed from limestone blocks, which has made them one of Africa’s oldest building materials.
These limestone blocks can be used to create complex architectural forms such as a circular entrance or a square entrance.
The southern and western gates of Benino City Walls, as well as the southern gate that was completed in 2013, were constructed with the same limestone blocks as the central and northern gates.
Although the central building is a large structure, it is only part of the structure.
There are several other buildings in the central, southern, and eastern parts of the wall.
The main gate is the central gateway, which houses the entrance to Beno City.
The eastern gate is built out of a massive, cylindrical structure called a “soul-shaped pillar,” which has a central dome and four smaller pillars.
The inner walls of the eastern and southern gates are built out from limestone that has not been used for building on the surrounding landscape.
The outer walls of these structures are made from sandstone that is not used for constructing buildings.
There is an interesting story about the construction of the western and southern gate structures.
According to the Benine, the Djangis built the southern and eastern gate structures to serve a ceremonial purpose.
The northern gate is for the use of a religious leader.
When a man dies, the gate will be used as an entryway into the afterlife.
The western gate is used for worship.
The story goes that the Djabodis, the northern rulers, were upset by the presence of outsiders entering their city from the north.
The rulers of Benido came to the people of the area and demanded that the people give them back their city.
Many Benin residents refused to give up their city, so they built a huge wooden structure to be used for the purpose of keeping the city secure.
The structure was a very elaborate, very beautiful structure.
They even built a statue of the people in front of it.
The king of the Djapadis, who was a descendant of the Prophet Muhammad, was one of many people who came to Benido and built a massive wooden structure with a giant statue of his father and mother inside.
The great wall in the center of Benobiyo City Walls was completed almost 10,000 and 11,000 year ago, respectively.
The vast majority of the stones on the walls were quarried and quarried into limestone.
In addition to being a UNESCO site, the Benino city wall is a national monument.
The Benin building that has the most significant feature is the building that is the heart of the building.
The Great Wall of Benor and Beno is made from limestone quarried from the Great Djabodo Basin in the south.
The large stone building that surrounds the Great Wall is one of three large buildings that make up the Great House of Benon. The other
|
<urn:uuid:ef6f13d4-c1ca-4927-818a-eccaf0a2c3c3>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.671875,
"fasttext_score": 0.3564099669456482,
"language": "en",
"language_score": 0.9801932573318481,
"url": "https://adinehgroup.com/2021/06/20/how-benin-city-wall-became-a-unesco-world-heritage-site/"
}
|
Archaeology breakthrough: 3D X-rays unravel mysteries hidden in ancient Egyptian mummies
The technique gives archaeologists an opportunity to dissect in great detail 2,000-year-old mummies without damaging the often delicate remains. The ancient Egyptians were known for their practice of mummifying humans alongside, crocodiles, bats, hawks and snakes. In many cases, the animals were buried along with their owners or were buried as a source of food in the afterlife.
A more common practice involved offering mummified animals to the gods at temples.
An estimated 70 million animal mummies were created by temple priests who bred or captured animals for this purpose alone.
Researchers at Swansea University have now analysed three animal mummies using a technique called X-ray micro CT scanning.
Previous investigations have revealed which animals were wrapped up in bandages, but little was known beyond that.
But thanks to the 3D X-rays, the researchers have created 3D models of the mummies’ insides.
The models were created at a resolution 100 times greater than a standard medical CT scan.
And standard X-rays only produce two-dimensional images.
Now, archaeologists can examine the animals’ teeth and bones in unprecedented detail.
The 3D models can then be printed out or placed into virtual reality for further analysis.
Using micro CT we can effectively carry out a post-mortem
Professor Richard Johnston, Swansea University
The team was led by Professor Richard Johnston of Swansea University, with experts from the university’s Egypt Centre and Cardiff and Leicester universities.
Professor Johnston said: “Using micro CT we can effectively carry out a post-mortem on these animals, more than 2000 years after they died in ancient Egypt.
“With a resolution up to 100 times higher than a medical CT scan, we were able to piece together new evidence of how they lived and died, revealing the conditions they were kept in, and possible causes of death.
“These are the very latest scientific imaging techniques. Our work shows how the hi-tech tools of today can shed new light on the distant past.”
Death Valley: Mystery of ‘200-year-old sailing stones’ solved [REPORT]
Remains of children amid 119 burials stun archaeologists [INSIGHT]
How archaeological discovery could prove Bible is right [INTERVIEW]
The researchers found the cat mummy contains the remains of a kitten less than five months old.
Separation in the kitten’s vertebrae suggests it may have been strangled.
The bird mummy most likely contains the remains of a Eurasian kestrel, also known as the common kestrel.
And the snake mummy most likely contains a small Egyptian Cobra.
The 3D X-rays unveiled evidence of kidney damage, suggesting it was starved of water during its life.
The snake was most likely killed by w whipping action before it had its mouth pried open for embalming.
Dr Carolyn Graves-Brown from the Egypt Centre said: “This collaboration between engineers, archaeologists, biologists, and Egyptologists shows the value of researchers from different subjects working together.
“Our findings have uncovered new insights into animal mummification, religion and human-animal relationships in ancient Egypt.”
The research was published this week in Scientific Reports.
Source: Read Full Article
|
<urn:uuid:aa659c4d-1cf9-4497-826b-ebd446040b76>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.984375,
"fasttext_score": 0.046929240226745605,
"language": "en",
"language_score": 0.9574423432350159,
"url": "https://magdelaine.net/lifestyle/archaeology-breakthrough-3d-x-rays-unravel-mysteries-hidden-in-ancient-egyptian-mummies/"
}
|
Pick from the Past
Natural History, November-December 1930
Caudal Appendages Adapted by Nature
to the Needs of Her Creatures
The raccoon’s tail am ringed all ’round;
the ’possum's tail am bare;
The rabbit’s got no tail at all;
but the white spot’s always there.
Woodpeckers have developed the practical habit of clinging to vertical surfaces and bracing themselves by means of their tail feathers, which in turn have become stiffened and thereby definitely modified for the purpose.
In the birds, the tail is formed internally by a short bony support, the pygostyle, and by the surrounding muscles, and externally by dermal elements, particularly feathers. It is in the feathers that the most obvious and interesting avian variation exists.
Perhaps in no group of animals have the tails become more specialized for purposes of ornamentation or display than in the birds, particularly in the males. In this regard, it is only necessary to mention such striking examples as the lyre bird, the bird of paradise, and the peacock. On the other hand, woodpeckers and chimney-swifts have developed the more practical habit of clinging to vertical surfaces and bracing themselves by means of their tail feathers, which in turn have become stiffened and thereby definitely modified for the purpose.
The wide variations shown by the tails of mammals are thoroughly interesting. For instance monkeys of the New World, belonging to the family Cebidae, nearly all have prehensile or grasping tails, but monkeys of the Old World, curiously enough, have only ordinary, non-prehensile ones, which may, perhaps, be considered decorative, but which perform no useful arboreal or gymnastic duties.
Then, there is the very short tail of the "cottontail" rabbit, which is covered by thick, soft, white, downy fur, as the common flame implies, and is consequently incapable of any monkey-like uses, but for all that it is still useful enough. Since the back and sides are brownish and much darker in color, this fluffy little ball is very conspicuous when the rabbit is running. Therefore, an enemy in pursuit of "bunny," be it man or beast, usually finds his attention fixed upon the "cottontail" rather than upon the prospective victim as a whole. This frequently results in the rabbit’s escape, for when it suddenly ceases its zigzag run and as suddenly squats to hide the tail from view, the pursuer frequently finds himself completely baffled, for with the disappearance of the "white spot" the whole animal seems to disappear.
The flying squirrel has a large, flattened, hairy tail, which serves as a balancer in his soaring jumps from tree to tree, but the opossum has a long hairless, prehensile tail that could not possibly aid its owner in the same manner.
In contrast to the rabbit’s type, the tail of the jumping mouse is sparsely haired and of an inconspicuous color. Moreover, instead of being short, and rounded, it is very elongate, measuring about twice the length of the body.
The flying squirrel has a large, flattened, hairy tail, which serves as a balancer in his soaring jumps from branch to branch and tree to tree, but the opossum has a long, hairless, prehensile tail that could not possibly aid its owner in the same manner. Instead, the opossum often grasps objects by winding its tail about them. This trait appears early in life, for each baby opossum thus clings tightly to "mamma" opossum’s tail as she swings it over her back and goes for a quiet evening stroll; while later, in the adult, the entire weight of the body may be easily supported from some convenient limb by this remarkable appendage alone.
There is an old saying that "if you pick up a guinea pig by the tail, its eyes will drop out." Since the caudal appendage is so short, being a mere vestige, guinea pig eyes seem perfectly safe. How fortunate it is, however, that the guinea pig does not feel called upon to show its feelings in the same way as does the dog, for it would have to wag the whole end of its body energetically to express a happy emotional state.
The muskrat and the beaver have much in common, for both of these rodents live in the vicinity of water, both are very fond of vegetable food, and both build more or less elaborate houses or dens for themselves, but when it comes to tails-the resemblances seemingly end. The muskrat’s tail is flattened vertically along its length, and while it may serve as a rudder in swimming, it is too weak to be used as a beaver uses his. The beaver’s tail, which is flattened cross-wise into a broad, paddle-like appendage, has developed an unusually strong set of muscles, so that it may be maneuvered both easily and effectually. This tool is used particularly in swimming and in personal broadcasting when danger threatens. Loud danger signals are often sent out to fellow beavers by a vigorous slap of the alert one’s tail on the surface of the water.
In remarkable contrast to the types just discussed, the whale and the porpoise have fleshy, bilobed tails, which suggest the fins of fishes but are set cross-wise of the body rather than perpendicular to it. In addition, they lack the bony supporting rays. Like many fishes, both the whale and the porpoise are specialized for life in the open seas.
Again, Nature has been especially generous with the kangaroo, in so far as his tail is concerned, whereas it has decidedly slighted the world’s champion heavy-weights, the elephant, the rhinoceros, and the hippopotamus. So strong is the kangaroo’s large tail that in times of danger it may support the entire weight of the body while the animal kicks viciously with its hind feet. At other times it is regularly used as a prop in sitting or as a spring or propelling force in locomotion. Exactly contrary to this condition, the elephant’s most useful appendage was placed in front of the body instead of behind, while the unlucky hippopotamus was cheated at both ends.
Return to Web Site Archive, Picks from the Past
|
<urn:uuid:005f9197-d45a-4ef1-a500-d70bd323383d>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5625,
"fasttext_score": 0.04082190990447998,
"language": "en",
"language_score": 0.967881977558136,
"url": "https://naturalhistorymag.com/htmlsite/editors_pick/1930_11-12_pick.html"
}
|
Skip to Main Content
Garfield Campus | Student Success Center (ABSE)
What is an annotated bibliography?
Some of the high school program research projects require students to write an annotated bibliography. An annotated bibliography is a list of all of the works (books, journals, websites, periodicals, etc.) that you cited in your paper and those items you reviewed.
Each source in an annotated bibliography includes an annotation. This is a short description of the content of a book or other source, and provides a critical look and evaluation of that source. It is not enough to simply summarize the source; you must also provide a detailed description and examination of it. Most annotations are 5 - 8 sentences long.
Items included in an annotated bibliography are not necessarily used as support or evidence in your paper. When writing an annotated bibliography be sure to include an annotation for each source you reviewed for your research topic. In addition to the annotation, each entry in your annotated bibliography should include a citation, written using MLA 8th Edition guidelines.
An annotated bibliography is not the same as a works cited list. A works cited list includes individual entries for all of the sources used in your research paper, but does not include annotations.
Below are more resources to help you understand and write an annotated bibliography for your research project. If you need more help, please visit the Garfield Campus Library to speak to a reference librarian.
What to include in an annotated bibliography
To write an annotation, include several details about the source's author and the work itself. Click here to open a blank form you can use to help you write an annotation.
These questions below are based on the Glendale Community College Library's guide How to Complete an Annotation for a Source. Don't worry if you can find an answer to every single question. Some of these questions might not apply to your source. Answer the questions you can to the best of your ability and use the answers to guide you in writing your annotation.
The following questions, along with the answers, give you an example of a completed form, using the book Nickel and Dimed: On (Not) Getting by in America, by Barbara Ehrenreich.
1. Who is the author and why should you pay attention to what he or she has to say? How is the author qualified to write about this subject?
Barbara Ehrenreich is a bestselling author with a background in science. She writes books about social issues and historical subjects and her articles have been published in Harper’s, The Nation, and other national publications.
2. What are the author's main ideas?
Ehrenreich focuses on the difficulty of making a decent living for those who work at jobs that pay minimum wage or just above it. Many workers have to work more than one job to support themselves and their families, and in some cases their physical health suffers. Many live in substandard housing because they can’t afford to live elsewhere.
3. What is the purpose of the work and how well does it address the subject? Is it a broad, general overview? Does it focus on something specific? Does it leave anything out?
The purpose of this work is to show how difficult it is to support oneself and a family when relying on minimum-wage jobs. By going undercover and working at several of these types of jobs, Ehrenreich provides a very focused study of these workers’ lives and the everyday struggles they face.
4. What is the author’s point of view, attitude or beliefs upon which the work is based? Are there signs of bias, such as strong language or a one-sided presentation of the facts/issues?
Her first-hand account of her experiences contain some bias, but she does report on her experiences objectively. Most of her writing deals with the workers themselves and their difficulties finding good-paying jobs and decent housing and the other difficulties in their lives.
5. Does the author seem to be trying to reach or influence a particular audience? If so, who is the intended audience? Scholars? General adult population? Everyday consumers? A group of people sharing a particular point of view?
Ehrenreich’s conversational writing tone and subject matter show that she’s trying to reach a general adult audience, possibly those who are fortunate enough to work in good-paying jobs with a college education and are interested in the problems of the working poor.
6. How does this source compare/contrast to others in your bibliography?
This book is a first-hand account of living below the poverty line and being unable to find better work because of lack of education and skills. The other sources in my bibliography deal with the economic consequences of poverty.
7. How does this source support/influence your thesis?
This supports my thesis that people who work in low-wage jobs have a difficult time getting out of poverty because of the psychological and physical toll of these jobs.
8. How is your source organized? Is there any supporting information that is helpful, such as appendices, index, notes, and list of sources cited by the author?
Ehrenreich organizes her book in chronological order. Because the book is a personal account, combined with a critique of social and economic issues in the United States, it does not contain an index or notes but does end with a Reader’s Guide of discussion questions.
Example of an entry in an annotated bibliography
MLA Annotated Bibliography" (1:08)
This short video from Craven Community College Library explains the reasons to write an annotated bibliography and what information you need to include about your sources in each annotation.
chat loading...
chat loading...
|
<urn:uuid:b207da9d-8657-4a88-b975-9ab4a6c36ed0>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.07647621631622314,
"language": "en",
"language_score": 0.9300062656402588,
"url": "https://campusguides.glendale.edu/c.php?g=616654&p=4585047"
}
|
Earwax might be gross, but scientists are getting behind a test that measures patients' stress levels through the unsightly substance.
Per The Guardian, the test measures levels of the stress hormone, cortisol, which can build up in a person's earwax. A psychiatrist at University College London Institute of Cognitive Neuroscience, Dr. Andres Herane-Vives, is interested in seeing how raised or lowered levels of cortisol can impact the body. So, he helped develop a test that can see the amount of cortisol a person produces through their earwax.
BBC describes cortisol as the "fight or flight" hormone. It sends alarms to the brain when a person encounters a stressful situation to trigger their instinctual response. Cortisol is known to impact every system of the body including digestion and sleep. But, some experts also believe that cortisol could play a role in anxiety and depression which can be further studied through Herane-Vives' test.
Cortisol can be measured through the blood but it only gives a small picture of how much of the hormone is produced. It can also be extracted from hair follicles, but one would need to produce at least 3 cm of hair for testing. As a result, Herane-Vives believes earwax testing will provide a more "more stable" description of cortisol's impact.
Herane-Vives was able to create a swab with a "break" in it so that the wax can be extracted without damaging the eardrum. Though the study is in its early stages, the researcher hopes to establish an "objective biological measure" for psychiatric conditions. It could also be used to measure other things such as glucose levels and/or antibodies against viruses.
|
<urn:uuid:e1bb6bf2-7a3c-438a-b1c8-45c74bf73584>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5625,
"fasttext_score": 0.7415202856063843,
"language": "en",
"language_score": 0.9255396127700806,
"url": "https://www.complex.com/life/2020/11/scientists-develop-new-method-of-testing-stress-through-earwax"
}
|
Nursing Book Club
The Doctors Blackwell by Janice P Nimura
We've come so far
It’s interesting to wonder what really motivates people, especially important historical figures. In her new book, The Doctors Blackwell, author Janice P. Nimura delves into the lives of groundbreaking 19th century female physicians Elizabeth and Emily Blackwell, hoping to better understand what made them tick.
Progressive Family
Elizabeth and Emily were born in Bristol, England, but their family emigrated to New York in 1832. Nimura writes that the Blackwells’ parents were “intellectually adventurous, politically engaged and prized the moral over the material.” In their family of nine children, the girls were granted “the same access to knowledge as the sons,” unusual for the time.
One of the most surprising things about Elizabeth Blackwell is that she had never really wanted to be a doctor, and she found the study of anatomy and disease disgusting.
However, when a family friend dying of uterine cancer lamented that she would have suffered less if she could have had “a lady doctor,” Elizabeth it took as a call to arms and a moral challenge.
The First Female M.D.
In the mid-1800s, the idea of a woman studying medicine, in the company of men, was unheard of. Elizabeth had a difficult time even finding a medical school that would take her.
Nursing Education
When the administrators of Geneva Medical College in Geneva, N.Y., asked students to vote on whether to admit a woman, most of the all-male student body (largely made up of local farm boys) assumed it was a joke.
Even Elizabeth’s mother was stunned when Elizabeth actually received her medical degree in 1849 and became the first female M.D. in the U.S. Elizabeth was not welcomed by the all-male medical community.
Even overseas, in Paris and London, hospitals refused to recognize her credentials. She reluctantly entered midwifery training at a Paris hospital for poor unwed mothers, where she contracted an infection that left her blind in one eye. Despite these obstacles, Elizabeth encouraged her younger sister to also study medicine.
Emily Blackwell earned her M.D. from Western Reserve University in 1854. She soon joined Elizabeth and Polish physician Marie Zakrzewska to establish the New York Infirmary for Women and Children, and later a medical college taught by and solely for women.
In addition to their hospital and training schools, the sisters were active in public health, establishing a staff of “health visitors” who would go into the homes of post-surgical women patients to promote better hygiene.
RN Career Events
A Crusader and a Scientist
The Blackwells’ motivations were complicated. According to Nimura, Elizabeth Blackwell wanted to push the boundaries of what women could accomplish, but had no real feel for the work involved in healing and didn’t have much compassion for others, even other women. She was not interested in joining the women’s movement or even in promoting women’s suffrage.
Emily Blackwell was less of a crusader than her sister, but Nimura says Emily developed a much greater enthusiasm for medicine and science, which helped her win over many skeptical male physicians and made her a better doctor. I found the Blackwell sisters’ private lives fascinating. They never married (although Emily had a female partner), but they remained close to their family and relied on each other for support.
Elizabeth eventually adopted a daughter, Kitty, who seems to have fallen somewhere between beloved child and devoted housekeeper, following her mother to England after Elizabeth retired in the 1870s. The Doctors Blackwell is not always an easy read, but it opened my eyes to how far professional women have come in the last two centuries.
It’s amazing to see how much the Blackwells had to struggle just to have their education and credentials taken seriously. All of us, men and women, owe them a debt of gratitude.
The Doctors Blackwell: How Two Pioneering Sisters Brought Medicine to Women — and Women to Medicine By Janice P. Nimura (W.W. Norton & Co., 2021)
Latest Articles
|
<urn:uuid:7db5e0ee-33f3-408f-9ce0-b8d89d01bfd5>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5625,
"fasttext_score": 0.04099535942077637,
"language": "en",
"language_score": 0.9810755848884583,
"url": "https://www.workingnurse.com/articles/the-doctors-blackwell-by-janice-p-nimura/"
}
|
From Nordan Symposia
Jump to navigationJump to search
Middle English crede, from Old English crēda, from Latin credo (first word of the Apostles' and Nicene Creeds), from credere to believe, trust, entrust; akin to Old Irish cretid he believes, Sanskrit śrad-dadhāti
A creed is a statement of belief—usually religious belief or faith—often recited as part of a religious service. The word derives from the Latin: credo for "I believe" (because the Latin translation of the Apostles' Creed and the Nicene Creed both begin with this word). A creed is sometimes referred to as a symbol (Greek: σύμβολο[ν], sýmbolo[n]), signifying a "token" by which persons of like beliefs might recognize each other.
One of the most widely used creeds in Christianity is the Nicene Creed, formulated in AD 325 at the First Council of Nicaea. Affirmation of this creed, which describes the Trinity, is generally taken as a fundamental test of orthodoxy for most Christian denominations. The Apostles' Creed is also broadly accepted. Some Christian denominations and other groups have rejected the authority of those creeds.
Whether Judaism is creedal has been a point of some controversy. Though some say Judaism is noncreedal in nature, others say it recognizes a single creed, the Shema. "Hear O Israel, the Lord is our God, the Lord is One."[Deut. 6:4]
Muslims declare the shahada, or testimony: "I bear witness that there is nothing worthy of worship except Allah, and I bear witness that Muhammad is the slave and messenger of Allah."
The terms "creed" and "faith" are sometimes used to mean religion. Where "creed" appears alongside "religion" or "faith," it can also refer to a person's political or social beliefs, for example The American's Creed.
|
<urn:uuid:503048a2-ab26-46f7-9b58-7f3dbafc69bc>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.640625,
"fasttext_score": 0.0794973373413086,
"language": "en",
"language_score": 0.9247517585754395,
"url": "https://www.nordan.daynal.org/wiki/Creed"
}
|
Double color flower
To create a double color flower.
Materials Required
1. White flower
2. Glass tumbler)
double color flower
Double color flower Science Fair Project
Fill two glasses with water and color the water in one glass red by using a dye. Then split the stem of a white flower and place half the stem in one glass, the other half in the other glass, as shown. After a few hours one side of the flower has turned to another color. This is because of capillary action carries water from the soil up through the roots of plants and trees, through the trunk or stem, and into the flowers and leaves. The liquid rises through sap tubes that produce the required capillary force.
|
<urn:uuid:efe76a96-59c5-4cff-9c81-4d15555379a0>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.671875,
"fasttext_score": 0.08073341846466064,
"language": "en",
"language_score": 0.9165219068527222,
"url": "https://www.sciencefair-projects.org/double-color-flower.html"
}
|
Publishers of technology books, eBooks, and videos for creative people
Home > Articles
Shadows and Occlusion
• Print
• + Share This
This chapter is from the book
Occlusion, in brief, is blocking, as in when an object blocks light. Technically, you could say that all regular shadows are kinds of occlusion, but most people reserve the term occlusion for a reference to other kinds of light-blocking that aren't regular shadows from a light. The few examples that follow should shed some light on different kinds of occlusion.
Ambient Occlusion
Ambient occlusion is a function designed to darken parts of your scene that are blocked by other geometry or less likely to have a full view of the sky. You can use ambient occlusion as a replacement or supplement to the shadows in your fill lights.
The main idea behind ambient occlusion is hemispheric sampling or looking around the scene from the point of view of each point on a surface. Figure 3.27 shows how rays are sampled in all directions from a point being rendered. The more of these rays hit an object (instead of shooting off into empty space), the darker the ambient occlusion. Ambient occlusion can usually have a maximum distance set for the rays, so that only nearby objects will cause the surface to darken.
Figure 3.27 This diagram illustrates the rays that would be sampled in rendering just one pixel with ambient occlusion. Ambient occlusion looks around the whole scene from the point being rendered, and darkens the point based on how many nearby objects are encountered which might be blocking light.
Ambient occlusion can be a terrific substitute for soft shadows from your fill light. You might still want your main light source, such as the sun, to cast a shadow, but your could turn off shadows from the surrounding fill lights, such as lights simulating illumination from the sky. In Figure 3.28, the brightest light source casts a raytraced shadow. The fill lights do not cast shadows, but ambient occlusion softly darkens the areas underneath and between objects, even in areas that are entirely within the raytraced shadow.
Figure 3.28 A scene with no shadowing on its fill light can look very flat (left), but adding ambient occlusion (right) provides extra shading that darkens areas that would not be exposed to the sky.
It would be possible to use ambient occlusion by itself, with no shadows at all in a scene, but this might produce too uniform a darkening effect in each area where two surfaces came together, and the audience might notice the lack of distinct shadows cast in a specific direction.
Compared to raytraced soft shadows from an area light, ambient occlusion can provide similar looking shading in your scene, but usually takes less time to render.
Occlusion in Global Illumination
Global illumination (abbreviated GI) is an approach to rendering in which indirect light is calculated as it interreflects between surfaces in your scene.
GI is different from ambient occlusion, which functions solely to darken parts of the scene. GI adds light to the scene, to simulate bounced or indirect light, essentially replacing both fill lights and their shadows.
With GI, objects block light by reflecting it away, just as real objects would. In Figure 3.29, occlusion is seen where the ground is darkened underneath the sphere. It looks very similar to a soft shadow from a light, but it is actually a natural part of global illumination, which grows darker in areas from which light has been reflected away.
Figure 3.29 Occlusion is an intrinsic part of global illumination, darkening the area under the sphere where light is reflected away.
It is possible to illuminate a GI scene with absolutely no lights. To prevent the scene from being pure black, you would need to provide something brightly shaded to start it off, such as the white cube in Figure 3.30, which has a high incandescence level on its shader. With global illumination, the bright white cube illuminates the whole scene, as if it were an area light. Where light bounces off the sphere, it does not reach the floor, so parts of the floor are occluded as a natural part of the GI process.
Figure 3.30 With global illumination, any bright object can be a light source and cast its own shadows, even in a scene with no lights.
In theory, productions could be lit entirely with incandescent objects. This would provide interesting options, such as the ability to model any shape you want and use it as a light source. However, this would also make the lighting and rendering process inordinately slow. In productions that use global illumination at all, it is most often used to supplement the direct illumination from conventional lights.
Other Types of Occlusion
Final gathering and image-based lighting are two more algorithms that are related in that they provide extra illumination, usually with built-in occlusion.
Final gathering (sometimes abbreviated FG) serves as a simplified form of global illumination. By itself, it can provide a relatively quick, single-bounce solution to adding both indirect light and soft occlusion to a scene, and it is becoming increasingly popular for this purpose. FG can also be used in conjunction with a full GI solution where it serves to smooth out and improve the quality of the global illumination.
Image-based lighting (abbreviated IBL) is an approach to rendering in which a sky dome surrounding the scene is mapped with an image of an environment, and the colors and tones from that image are used to illuminate the scene. The process of rendering with IBL often uses a similar rendering technique to those used in rendering GI, and it will often include similar built-in occlusion. In renderers that do not provide built-in occlusion in IBL renders, IBL can be combined with ambient occlusion.
Chapter 4, "Lighting Environments and Architecture," will talk more about GI, FG, and IBL.
• + Share This
• 🔖 Save To Your Account
Peachpit Promotional Mailings & Special Offers
Collection and Use of Information
Questions and Inquiries
Online Store
Contests and Drawings
Service Announcements
Customer Service
Other Collection and Use of Information
Application and System Logs
Web Analytics
Cookies and Related Technologies
Do Not Track
This site currently does not respond to Do Not Track signals.
Pearson may send or direct marketing communications to users, provided that
Correcting/Updating Personal Information
Sale of Personal Information
Supplemental Privacy Statement for California Residents
Sharing and Disclosure
Pearson may disclose personal information, as follows:
• As required by law.
Requests and Contact
Changes to this Privacy Notice
Last Update: November 17, 2020
|
<urn:uuid:ee9382cc-6592-4119-8fa4-a0652071c28d>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.796875,
"fasttext_score": 0.06178891658782959,
"language": "en",
"language_score": 0.9213241934776306,
"url": "https://www.peachpit.com/articles/article.aspx?p=486505&seqNum=7"
}
|
From Simple English Wikipedia, the free encyclopedia
Jump to navigation Jump to search
An old fashioned theodolite, this kind is rarely used in modern times
Student using theodolite
A theodolite is a tool for measuring angles between two places (or points) from one place. They are usually associated with surveying. They are often mounted on a special kind of tripod.[1][2]
They are usually a telescope on a mount that can move horizontally (left and right) and vertically (up and down). The mount has a scale where the readings are taken, usually in degrees for older models and arc minutes or arc seconds for newer models. The telescope normally has a crosshair to make it easy to align it to the points to be surveyed. The theodolite was the first tool that could do vertical and horizontal measurements in the same device.
Most modern theodolites are electronic and the readings are read from a digital display.
A transit is a kind of theodolite that can do a whole circle vertically and horizontally.
References[change | change source]
1. Daumas, Maurice 1989. Scientific instruments of the seventeenth and eighteenth centuries and their makers. 1989. Portman Books, London. ISBN 978-0-7134-0727-3
2. Anita McConnell 1992. Instrument makers to the world. ISBN 978-1850720966
|
<urn:uuid:435f3df6-be4b-47d5-a88a-105d7fa3bdb8>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.828125,
"fasttext_score": 0.38301950693130493,
"language": "en",
"language_score": 0.8839521408081055,
"url": "https://simple.wikipedia.org/wiki/Theodolite"
}
|
kids encyclopedia robot
Multiverse facts for kids
Kids Encyclopedia Facts
Physical cosmology
WMAP 2010.png
Universe · Big Bang
Age of the universe
Timeline of the Big Bang
Ultimate fate of the universe
A multiverse is the theory of a conjectured set of multiple possible universes, including ours, which make up reality. These universes are sometimes called parallel universes. A number of different versions have been considered.
The term "multiverse" was coined in 1895 by psychologist William James as a philosophical concept.
The cosmological multiverse
The cosmological multiverse tries to explain why the universe we observe i.e. ''our universe'' seems so welcoming to the emergence of life. Even small changes to the way physics works would make life impossible. In a multiverse a vast number of universes are randomly created and some happen to favour life emerging there. Many inhospitable universes would also have been created, but there would be no life there to observe their existence.
The quantum multiverse
The quantum multiverse is another version in which our universe splits into alternative futures with every quantum event. This is called many-worlds interpretation of quantum mechanics.
kids search engine
Multiverse Facts for Kids. Kiddle Encyclopedia.
|
<urn:uuid:0a213fee-f27f-4e39-8012-b4f4ccd73745>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5,
"fasttext_score": 0.950921893119812,
"language": "en",
"language_score": 0.9192807674407959,
"url": "https://kids.kiddle.co/Multiverse"
}
|
Skip to content ↓
Wordsworth Primary School
Primary School
Summer 2 - Invasions (Anglo-Saxons & Vikings)
The Vikings
In Summer 2, we are learning all about the Vikings.
24/06/20 - Viking Timelines
This weeks History is carrying on with the Vikings and Anglo-Saxon period of British history. Below you will find a presentation of that time period. There is a differentiated activity sorting out the facts to go on a timeline. the difficulty is rated by stars, 1 star the easiest to 3 stars the most challenging. You don't need to do all three. After this there is a poster to create, a template is below, where you can fill in what you have discovered.
20/05/20 - Fascinating Facts
Using the page below from BBC Bitesize, we would like you to write 8 interesting facts about the Vikings. Who were they? Why did they come to Britain? Was your initial impression about the Vikings from last week correct?
13/05/20 - Vikings First Impression
Today's task is to tell your teacher what your first impression of the Vikings is, using evidence from the sources provided? Do they seem like a kind people? Do they seem interesting, or rather dull? Why do you think this? Best of luck!
|
<urn:uuid:ec182034-8119-4009-ad35-cf6f4cc26b71>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.984375,
"fasttext_score": 0.027608156204223633,
"language": "en",
"language_score": 0.9345274567604065,
"url": "https://www.wordsworthprimary.co.uk/page/?title=Summer+2+-+Invasions+%28Anglo-Saxons+%26amp%3B+Vikings%29&pid=405"
}
|
The process by which animals erode hard hard surfaces such as rocks and coral reefs, through drilling, grazing and burrowing. Bioerosion from organisms and animals who remove hard substrates is slower compared to erosion from storms or floods. However, over time the effects of bioerosion can be extraordinary. For instance, there is a theory that The English Channel is a result of bioerosion. Geologists and paleontologists are particularly interested in patterns of bioerosion because it can tell us a great deal about prehistoric sea levels, climatic conditions, and community evolution. Bioerosion traces in ancient limestones of the Bahamas, for example, have given us a direct indication of a rapid global sea level change about 125,000 years ago.
|
<urn:uuid:398015cb-be06-4663-8d4c-2f3c21090260>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 4,
"fasttext_score": 0.44296133518218994,
"language": "en",
"language_score": 0.9290576577186584,
"url": "https://recyclenation.com/green-glossary/bioerosion/"
}
|
Art of Old Russia: russian icon painting
more than a year ago
By officially accepting Christianity in 988, Ancient Rus' also accepted the Byzantine culture thanks to which religious art appeared in the country. The period between the 10th and 17th centuries is considered the Middle Ages era in Russian history. During this time, religion played a central role in the country. A large amount of churches and cathedrals were built, adorned inside with mosaics, frescas and, of course, icons.
Nowadays, the most valuable icons are usually kept in museums because these organizations can provide them with the best care. The technique of icon painting employs tempera on gesso board. In order for the icon's colors to be brighter, it was often covered with a layer special drying oil but, unfortunately, after about 70-100 years this oil became darker and darker. It was often removed and the darkened areas were painted over. One can say that the icons that we can see in museums today were "restored" for the first time already hundreds of years ago.
Radical reforms introduced by Peter the Great in the first quarter of the 18th century led to a sharp decline of religious art. Icons were no longer admired as a work of art and the especially worshipped ones were not restored and, therefore, became so dark that one could only with great difficulty make out and forms or objects. Oftentimes icons were referred to as "black boards" and interst towards them as collectible pieces of art was close to non-existent. An interest in ancient Byzantine art first arose at the St. Petersburg Academy of Arts and so pieces of such art began to be collected and used as educational material. However, at the turn of the 20th century the demand for ancient Russian art began to grow and members of the royal family as well as private collections began to acquire old icons. The imperial collection is now displayed at the Russian Museum and numbers more than 5,000 pieces of ancient Russian art.
The oldest icon on display at the museum's exhibition emanates from the 12th century and is called "Gold-haired Angel" ("Archangel Gabriel"). It is assumed that this icon was painted for a Russian church by a Byzantine master and its name comes from the little strings of gold that the angel has in his hair. These strings symbolize the Kingdom of Christ.
Some of the most renowned icon painters of Ancient Russia include a monk by the name of Andrey Rublev and his follower Dionisy. Both exhibited a complex approach to their work: decorating cathedrals with frescas and creating icons for the iconostasis. Andrey Rublev gained fame after completing the iconostasis for the Uspensky Cathedral in Vladimir (two of the icons from it are displayed at the Russian Museum).
Connect via social media
google sign in button
Please enter your name*
Please share your location
Enter your message*
Put our app in your pocket
|
<urn:uuid:a56b5f16-45d6-434d-9962-3d55e107672b>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.53125,
"fasttext_score": 0.022834956645965576,
"language": "en",
"language_score": 0.9753546714782715,
"url": "https://www.inyourpocket.com/st-petersburg-en/art-of-old-russia-russian-icon-painting_74666f"
}
|
September 15, 2021
Guided Primary Source Analysis: The Alaska Line
Last Updated on April 6, 2020
The Alaska Line
Alaska Steamship Co. “The Alaska Line.” 1934. Library of Congress Geography and Map Division
For each of the following questions, use specific details from the map to support your conclusions (zoom into this map online or download a larger image). Who created this map? How do you know? Why do you think this map was created? Who do you think the audience might have been when it was published in 1934?
How many different transportation lines are represented on this map? How many different modes of transportation are represented? Choose two points (look for the red points and find the associated names) on the map and challenge a friend to tell you which modes of transportation and which transportation lines a person would need to use in order to get from one point to the other.
Choose one interesting fact represented on this map that would be possible to investigate further. Is the information still true today? What else did you learn about this area or feature?
Today in History: Alaska
Speak Your Mind
|
<urn:uuid:e7eff876-52e5-4705-9b78-5826c360710a>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 4.125,
"fasttext_score": 0.02264726161956787,
"language": "en",
"language_score": 0.950102686882019,
"url": "https://primarysourcenexus.org/2014/11/guided-primary-source-analysis-alaska-line/"
}
|
A History of Disney Toons
A History of Disney Toons
To learn how to write in toto, you need to know the Latin roots of the word. In toto means “all together,” “all,” or “neither.” You may find in to English, in an official document or in a book of literature, that someone has spoken to you in toto, indicating that you should take the advice indicated in toto. Another example would be when you are taking a test in college and the teacher indicates that one of your answers is incorrect. You can correct it in toto by repeating the question or making a correction, whereas if you had made a different answer, the correction would be to alter the definition of the question to mean that you did not answer it correctly.
The term toto appears only once in the entire English language, as part of a list of Latin adjectives, although it does appear in some other languages. According to Halliday and Driver, the toto adjective is derived from toto, which in turn is derived from toto circa, “a shoe,” or toto cadence, “a running pace.” The phrase toto circa appears to be a forerunner of the term toto. Toto, however, does not appear in any English dictionary, so it is very unlikely to be found outside of the languages in which the English toto is spoken. For example, the phrase toto circa liberata, “freedom of movement,” in Spanish, means “of a running or walking pace,” so this phrase would not be familiar to a person who had learned to speak only English.
The Tin Man makes an appearance in a number of fairy tales, but the most famous version shows the Tin Man making a visit to Kansas in the late 1800s. The novel begins with the narrator traveling to Kansas with his friend Dora. Together they plan to see a world-famous magician, whom they believe can solve the mystery of their world. During their trip, the Tin Man falls in love with Dora, and the two of them travel to the Magic Kingdom where they meet the original Cinderella.
The first lines of the story tell us that the Tin Man has no magic powers; he cannot put anyone to sleep or cause anyone to speak in sentences. He can, however, make all kinds of noises, which is what he uses to charm Dora. The noises sound very much like those that tin men make when they are being paid to perform. It is through the repetitive sound of the tin man that we are introduced to the world of magic, where only a few people have the power to perform its tricks.
As the story of the Tin Man and Dora progresses, we learn more about the background of both characters. We learn that they live in Kansas, where the winters are freezing cold and the summers are hot and humid. Eventually, we discover that the goods have been hired by a very rich uncle to help him organize his store-room.
Dora and the Tin Man become friends and work well together, as well as battling monsters and the villains that haunt their ways. The most famous scene from the series is the one where Dora, after discovering a box full of unusual toys, places them all in a carton and leads it across town to a huge fair. At the fair, she meets her first real fairy, and the books describe the adventures of their journey. Some other minor Disney characters also appear at various points in the series. Overall, todos are very popular among children and grownups, and are some of the best-known Disney characters.
This entry was posted in Uncategorized. Bookmark the permalink.
|
<urn:uuid:8ab7cb5d-8f65-4493-b50e-f9937ca5fbc4>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5,
"fasttext_score": 0.06376582384109497,
"language": "en",
"language_score": 0.9746687412261963,
"url": "https://mutthousethemusical.com/2021/09/10/a-history-of-disney-toons/"
}
|
The Muffin M-an Family
4 teachers like this lesson
Print Lesson
SWBAT identify rimes in "The Muffin Man" nursery rhyme, and retell the nursery rhyme "The Muffin Man". Student Objective: I can rhyme words in the -an word family. I can recite "The Muffin Man".
Big Idea
A great way to introduce the word family -an is by using the idea of the Muffin Man.
10 minutes
Each day, my students gather at the classroom rug for our literacy block. Today I am introducing the nursery rhyme of the "Muffin Man". Through the use of nursery rhymes, I can teach word families; in this case, the -an family. By introducing rime through familiar text helps the children to comprehend the concepts taught.
Time for our literacy block! Would you please come join me on the rug so that I can share our newest nursery rhyme? Take a look at this picture. If you have an idea who this nursery rhyme character is, please blow it into your hand. Okay, release. It is "The Muffin Man"! What were some of the things that indicated to you that this was "The Muffin Man"? (Have the children describe the picture.) How many of you have had a muffin before? Share with a friend a flavor of muffin you like to eat.
Do you think that this rhyme could be true? (Explain that "The Muffin Man" could be real because we can go to a bakery and buy muffins.) When things are true, they are called real. When stories are about real things, we call that realistic.
What do you think is going to happen in this rhyme? I would like you to listen carefully to find out if your predictions are correct.
25 minutes
Nursery rhymes are short in length and full of repetitions. Children can quickly internalize the language and make them their own. These memorized rhymes are ideal vehicles for playing with language and developing phonemic awareness. I direct the children to come to the rug:
Listen as I read: O, Do you know the Muffin Man, the Muffin Man , the Muffin Man?
Do you know the Muffin Man who lives on Drury Lane?
Yes, I know the Muffin Man, the Muffin Man , the Muffin Man.
Yes, I know the Muffin Man who lives on Drury Lane.
Turn and talk to your neighbor and tell them where you can get muffins.
Now we are going to do an echo chant of this rhyme. Look at this poster as I point to the words. I am going to say the first line, and then I will point to the words as you repeat what I said. When you echo, you will say the exact words that I say. We will read the whole rhyme in this way, and then I will ask you some questions about the Muffin Man.
What is the Muffin Man? (a baker)
What does he do? (he sells muffins)
Who do you think the author is asking the question, "Do you know the Muffin Man?" Who is answering back?
Write the word man on a chart paper or board.
Children, read this word to me--man. Man is one of the words in the -an word family. Let's stretch this word out so that we can hear all the sounds m...a...n... Let's listen to just the ending sounds now: a...n...
We are going to make a list of words that end with the -an sound. We will start at the beginning of the alphabet, make the beginning sound, and then add -an. Let's try this. B-an, ban--this is a real word that means to choose not to do something, but it is not the word band, like marching band. Band ends with a "d" and we are not looking for words that end in "d" we are looking for words in the -an family. What letter do we have next? "C" Let's try: c-an, can.
Go through the entire alphabet making these connections. You may have students whose name rhymes with -an. Add these to the list, too. Once you have made your list read it to your students one more time.
We are going to take the words that we have discovered, and we are going to make a chef's hat. I have a tray of muffins for you, too. Your hat will be made from a sentence strip and a design from a paper that you will need to cut out. The tray of muffins is a picture of muffins with -an words typed onto them. You will need to trace and read the -an words on the muffins and color them in. Remember, if you are the Muffin Man, you are going to want to make your muffins look very tasty so that they will sell. If your work is sloppy, no one will want to buy your muffins. When you have finished both items, you can retell the rhyme to a friend.
10 minutes
As the children get their papers, and before they get to work, it is fun to play a song version of the "Muffin Man".
You have read and retold the rhyme of the Muffin Man, now I would like to see if you can take the words that you have learned from the -an family, and read to complete a paper that graphs the -an family. To begin, you must have a red, yellow, green and blue crayon, and a pencil to write your name. To help you organize your work, look at the box at the top. I would like you to cross-out one word "can" with your red crayon and then color in one box above the can. Do this for each word can and then move on to the next words. (Then, fan with yellow, man with green and pan with blue).
When you have finished this work, raise your hand and I will look at what you have done.
I will ask the children to read the words to me and than I can check if they have absorbed the lesson or if they are just mimicking someone else.
|
<urn:uuid:c5aa0cdb-16ae-470d-acec-ae52ca2eefa3>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.609375,
"fasttext_score": 0.023531317710876465,
"language": "en",
"language_score": 0.9429489970207214,
"url": "https://betterlesson.com/lesson/resource/2898155/muffin-man-pic"
}
|
What is mindfulness?
A dandelion with seeds floating in the air in the foreground. blue sky background.
Mindfulness is the basic human ability to be fully present in the moment and calming the mind despite what’s going on around us. A concept with many meanings and interpretations, often viewed as non-judgmental awareness to the present moment.
With mindfulness, happiness is found in accepting the moment as it presents itself. By being aware of what’s happening in the "now," you are able to shift out of “autopilot” and see the world around you.
Benefits of Practicing Mindfulness
1. Can reduce stress, anxiety, and depressive symptoms.
2. Improves memory and concentration which can be beneficial for academic performance and success.
3. Helps in overall health and well-being by improving sleep quality, lowering blood pressure and reducing chronic pain.
4. Enhances self-awareness that helps you to develop strong understanding about yourself and grow stronger emotionally.
Practicing Mindfulness
Here are some few ways in which you can practice mindfulness:
1. Enjoy a stroll and notice the sights around you, try connecting with nature. (examples - smelling flowers, listening to birds, feeling your feet hit the ground)
2. Practice deep breathing. Focusing on your breath - slowly inhaling and exhaling air.
3. Try mindful eating by being aware of each bite and recognizing when you are full. Allowing yourself to become aware of the positive and nurturing opportunities that are available through food selection by respecting your own inner wisdom.
4. Mindful coloring. Take time to be creative, look at the way the color meets the page, and enjoy the process.
5. Practicing Gratitude. There is no correct way of practicing gratitude, but keeping a gratitude journal is a great way to start.
Additional Resources
Mindfulness can be practiced anywhere and anytime by anyone.
|
<urn:uuid:5dd79ec5-e894-47da-b667-ec4252949293>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.7155704498291016,
"language": "en",
"language_score": 0.9432592391967773,
"url": "https://www.gvsu.edu/studentwellness/mindfulness-40.htm"
}
|
African Tree pangolin with an inset showing a keratinized scale. Arrows indicate the direction of growth.
Scientists from the University of California, San Diego and ETH Zürich have studied an unusual mammal – the pangolin – to learn the secrets of its protective outer armor [Wang et al., Acta Biomaterialia (2016),].
When predators threaten pangolins, they roll up into a ball exposing hard, sharp-edged scales. These tough yet flexible scales are made of a hard nail-like material. For the first time, lead author Bin Wang along with Wen Yang, Vincent R. Sherman, and Marc A. Meyers have studied the structure of these scales in detail – from the nano- to the meso-level – using typical materials analysis techniques and microscopy to understand their unique mechanical properties.
“The pangolin is [a] fascinating organism because it has an armor that can resist powerful predators such as lions and tigers,” say Wang, Yang, and Meyers. “We [have] revealed the intricate architecture of the scale which enables the animal to protect itself.”
At the nano-level, the scales consist of layers of flattened cells protected by a fibrous protein called keratin. But unlike most other keratinous material, in the pangolin’s scales these layers or lamella are stacked in different orientations up to create a crossed structure. Along with crossed fibers, the scales contain a nanoscale suture-like structure that creates an interlocking interface between the lamellae.
“The keratin fibers have a complex three-layer arrangement,” explain the researchers. “In the outer and inner layers, the fibers are parallel to the surface but in the core the fibers have a varying orientation. The crossed lamellar arrangement of the keratin fibers in the pangolin scales enhances the fracture toughness.”
The complex, hierarchical structure makes it hard for cracks to propagate after an impact, resulting in a Young’s modulus of ~1 GPa and a tensile strength of 60-100 MPa. But the properties of the scales depend on how a strain or force is applied. When impacts are quick, the scales provide higher stiffness and strength, but also have the ability to absorb energy when strain is applied more slowly.
The arrangement of the scales in an overlapping hexagonal pattern around a central scale also ensures that no part of the pangolin is exposed when it moves or curls up. The arrangement also enables scales to slide over each other, making the armor very flexible.
The researchers don’t yet know whether their study will lead to new bio-inspired materials, but the combination of mechanical properties offered by pangolin scales could be exactly right for human body armor.
“Our goal is to identify unique features in biological materials,” say Wang, Yang, and Meyers. “The next step is to develop composites inspired by the designs of nature.”
|
<urn:uuid:27be51dc-dbc1-4e5f-877d-409d2aba4179>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.796875,
"fasttext_score": 0.02932828664779663,
"language": "en",
"language_score": 0.8888553977012634,
"url": "https://www.materialstoday.com/biomaterials/news/pangolins-inspire-flexible-armor/"
}
|
December 1941
US and World Events plus Additional Resources
On December 20, 1941, senior Chinese officials in Chungking reported Claire Lee Chennault’s name to United Press International reporters to commemorate the first aerial attack made by the international air force called the American Volunteer Group on Japanese ships. Claire Lee Chennault was the commanding general of the Fourteenth Army Air Force in China during World War II and the leader of the Flying Tigers.
Chennault grew up in Louisiana and was a member of the U.S. Air Service during World War I. After a career as an instructor at the Army Corps Tactical School, Chennault retired in 1937 and left the U.S. for China where he became an advisor to Chiang Kai-shek.
Chennault was sent to the United States during the beginning of World War II to recruit for an American-supported air force in China. He convinced FDR to authorize the purchase of fighter jets for China as well as to allow American military pilots to leave active duty to fight with China. This group of pilots became known as the Flying Tigers, and by December 1941 they were able to make strides against the Japanese. Chennault spent most of the war advocating to FDR for more air power in China. He retired in July 1945 and returned to China.
|
<urn:uuid:19c01bf7-0f01-4c05-be7f-5d26abaee5b9>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.02271091938018799,
"language": "en",
"language_score": 0.9747032523155212,
"url": "http://www.fdrlibrary.marist.edu/daybyday/event/december-1941-13/"
}
|
Elementary Particles
I have already mentioned that quarks have some bizarre characteristics. It is now time to review them.
Particle physics was in a state of confusion during the 1960s. With the advent of new high energy particle accelerators and particle detectors, a large number of hadrons were discovered by the 1960, and it was unclear how these various particles were related to each other.
In 1961 a classification scheme called the Eightfold way was developed by Murry Gell-Mann for these newly discovered particles. We will talk about the Eightfold way, later, when we discuss the role of symmetry in physics. The Eightfold way, much like the periodic table of the elements, not only provided a semblance of order for these newly discovered particles, but it also predicted the existence of particles that not had yet been discovered (all of those predicted particles were discovered later). But the question was: Why is this classification scheme so successful?
In 1964, Gell-Mann and George Zweig independently proposed quarks as the building blocks of hadrons, because they realized that quarks could be the basis of this classification scheme. Initially, the quark model had three types of quarks: the up, down, and the strange. The up quark has a charge +2/3, the down quark has -1/3 and the strange quark has -1/3. While the quark model was very successful in accounting for all the known hadrons, it raised more questions than answers, particularly during the early days of its introduction. Fractional charges were really strange and unacceptable to many because no particle in nature was ever found with a fractional charge. So the general point of view in 1966 was that quarks were most likely just mathematical devices, useful but not real.
All that changed in 1968, when the results from the electron-proton scattering experiments conducted at the Stanford Linear Accelerator Center (SLAC) by Jerome Friedman, Henry Kendall, and Richard Taylor showed a pattern of rare large angle scattering of the electrons. The incoming electron passed through the proton without much deviation. But occasionally an electron scattered with a large angle from one of the “constituents”. The physicists inferred that the protons are indeed made up of three compact constituents called quarks. The experimentalists were originally not able to determine if these “point-like constituents” had the correct fractional charges. Determining the fractional charge proved to be a much more difficult problem and the answer came when the results were compared with the neutrino scattering measurements conducted at CERN which demonstrated without a doubt that the quark model was correct. Physicists who strongly doubted the existence of quarks finally had to accept them as real.
Friedman, Kendall, and Taylor were jointly awarded the 1990 Nobel Prize in physics “for their pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics”.
Physicists were slow in accepting the quark model mainly because quarks were never seen as isolated particles outside of the nucleus. In addition, accelerator experiments revealed the existence of short-lived particles such as \Delta^{++} and \Delta^- made up only of up quarks (uuu) and down quarks (ddd), respectively. Their existence seemed to violate the Pauli Exclusion Principle according to which no two identical spin-half particles can have the same set of quantum numbers in the same state. But the quarks are indeed spin-half particles having the same set of quantum numbers in the uuu and ddd combinations.
In 1965, Moo-Young Han of Duke University, Yoichiro Nambu of the University of Chicago and Oscar Greenberg of the University of Maryland at College Park found a way out of this predicament. Their proposal was to introduce a new quantum number that made the quarks distinguishable. The new quantum number was called color charge. Quarks come in three different “colors” and only mix in such ways as to form colorless objects. For example, a proton is made up of two up quarks and a down quark (see Figure 3-1). One of those quarks will be red, one will be blue, and the other will be green; together they will make white, which is colorless. In case of the \Delta^{++}, each quark type could exist in three color states, e.g. u-red, u-green and u-blue, so that the combination no longer violated the Pauli principle. The requirement that only color-neutral objects can exist as free particles explained the occurrence of bosons (three quarks). Antiparticles would carry anticolor so that the quark–antiquark combination in mesons could also be color-neutral.
So we see all observed particles in nature are color neutral. But why are quarks never found in free state? The simple answer is, if one tries to pull apart a color neutral hadron, a spray of new hadrons are produced which are color neutral themselves.
Let’s explore this idea in details. We know the gluons are the carrier particles of the strong force. The color-force field inside the hadrons consists of gluons holding the quarks together. The quarks can move freely inside hadrons and exchange gluons continuously. If one of the quarks in a given hadron is pulled apart, as is done in high energy accelerators, the color-force field “stretches” between that quark and its neighbors. More and more energy is pumped into the color-force field as the quark is pulled with greater force. At some point, it is energetically advantageous for the color-force field to break into a new quark-antiquark pair. The energy is conserved because the energy of the color-force field is converted into the mass of the new quarks, and the color-force field can revert back to the normal state.
On the other hand, the SLAC deep-inelastic scattering experiments were still puzzling. It was as if the quarks inside a proton are nearly free and not subject to any force. The higher the energy of the electron beam, the more the electrons “reacted” as if they were encountering particles moving freely inside the proton. But when the distance between two quarks increased, the force became greater—an effect analogous to the stretching of a rubber band. Physicists coined the term “asymptotic freedom” to describe the way quarks seemed to interact more and more feebly at higher energies. In 1969 Richard Feynman proposed his “parton” model to describe the dynamics, in which a nucleon is composed of a number of point-like constituents called partons. Feynman’s partons were later identified as quarks and gluons. Interestingly, Feynman’s arrived at his parton picture while trying to interpret the SLAC data, while Gell-Mann’s quark idea came from the notions of symmetry.
But there seemed to be a contradiction between asymptotic freedom and quark confinement. How could nuclear forces be both strong enough to account for the permanent confinement of quarks and weak enough to be asymptotically free inside the hadrons?
David Gross, then at Princeton University, and his graduate student Frank Wilczek, and independently, David Politzer, then a graduate student at Harvard University, discovered why quarks behave almost as free particles only at high energies and why on the other hand, is it so difficult to dislodge a free quark from its hadron casing. At the beginning, Gross and Wilczek did not expect asymptotic freedom could be a feature of any legitimate quantum theory of particle interactions. Surprisingly, they found the exact opposite to be true. They discovered a class of theories in which the strength of the interaction becomes steadily smaller at shorter distances. David Politzer independently came to the same conclusion. Their papers appeared back-to-back in Physical Review Letters (PRL).
The strength of an interaction depends on a factor called the “coupling constant”, denoted by \alpha_s. Figure 6-2 shows a compilation of \alpha_s obtained from many different experiments, versus the energy μ of the exchanged gluons, plotted on a logarithmic scale (gluon energy is measured in GeV). Notice that at lower energies, or longer distances, the value of \alpha_s gets progressively higher. At very low energies or at very large distances, \alpha_s essentially is infinite (not shown in this diagram), while at very high energies when the quarks are squeezed very close together, \alpha_s, or the strength of their interaction becomes progressively weaker. This quintessentially is asymptotic freedom as theorized by Gross, Politzer, and Wilczek. Quarks are confined inside hadrons and cannot be liberated as free particles. At high enough energies a struck quark will “hadronize” by combining as a quark triplet or a quark-antiquark pair.
Although a complete theoretical proof for absolute quark confinement does not exist even today, most physicists find Gross, Politzer, and Wilczek’s theoretical arguments convincing. The discovery laid the foundation for theory of the color interaction (or Quantum Chromo Dynamics, QCD) and the 2004 Nobel Prize in physics was awarded jointly to David J. Gross, H. David Politzer and Frank Wilczek “for the discovery of asymptotic freedom in the theory of the strong interaction”.
It turns out that QCD is mathematically remarkably similar to QED. In QED, the force between two electrically charged particles is mediated by the exchange of a photon between the two charged particles while in QCD, the quarks carry a different kind of charge, the color charge, and the force between two colored particles is mediated by the exchange of a gluon. The crucial difference is that while the photons of QED carry no charge, the gluons of QCD carry the color charge. A quark is surrounded by a sea of “virtual” gluons arising due to quantum fluctuations. In QED, the quantity α = e²/4π is called the fine structure constant, a dimensionless number whose value is ≈ 1/137. In QCD α is not a constant—it decreases with increasing momentum and its distribution demonstrates the main characteristics of strong interaction.
QCD also explained another odd aspect of hadrons. If you tally the masses of constituent quarks, you will find only a very small part of the mass of a hadron is actually due to the individual quarks. QCD indicated that proton’s mass, for example, arises because of the energy tied up in the strong binding of the three quarks.
Leave a Reply
WordPress.com Logo
Google photo
Twitter picture
Facebook photo
Connecting to %s
|
<urn:uuid:dd623b78-ee41-4f3e-a69d-4e87fb0a89af>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.75,
"fasttext_score": 0.214144766330719,
"language": "en",
"language_score": 0.9430060982704163,
"url": "https://cosmicglimpses.blog/2015/08/31/elementary-particles/6/"
}
|
Examples of Typology: Definition and Use Across Different Disciplines
What is typology? The term typology refers to studying, examining, classifying, or analyzing things or concepts according to different types or categories. Typology can be used across all industries and disciplines. A few examples of fields in which typology is used include theology, anthropology, archaeology, linguistics, psychology, politics, education, medicine, farming, and many others.
example of typology types of vegetables example of typology types of vegetables
Typology Meaning: Understanding the Concept
Before reviewing typology examples, it's important to really understand the definition of typology. Understanding what typology is will make it easier to understand how certain examples illustrate the concept. A typology is simply a means of classifying items, people or concepts by general type. The word typology is simply a scientific term for grouping things together based on similarities.
• Typology is most often used to classify people, things or ideas into categories based on commonalities that they share.
• Using typology helps researchers and others better understand certain conditions or factors by grouping things with similar characteristics together.
• Typology is also beneficial in everyday life. Categorizing similar things together provides a framework for processing, organizing and understanding information.
Examples of Typology in Many Fields
Since typology can be used in every field or industry, it's not surprising that there are many different typology examples. Some typologies are usually used by academic or professional researchers, but many others are used by ordinary people practicing their chosen profession or even in everyday life.
Anthropological Typologies
Typologies are very important to the field of anthropology. Anthropologists often classify civilizations and other groups of people by culture, beliefs or practices. They also use various traits to classify artifacts.
• sociopolitical typology - Anthropologist Elman Service proposed a sociopolitical typology in 1962. Service's typology grouped political organizations into four different categories based on their structure and perspective. The categories associated with this typology are band, tribe chiefdom and state.
• anthropological fields - The field of anthropology can be viewed in the context of typology, as it is classified by specific areas of study. A typology of the field of study includes numerous categories like applied, archaeological, biological, cultural, forensic, and linguistic anthropology.
Examples of Language Typologies
The evolution and nuances of language can be better understood when similar languages with common traits are grouped together. Grouping languages by typology makes comparisons more manageable than if one broadly attempted to compare and contrast all languages simultaneously.
• linguistic typology - Linguistic typology is a specific branch of linguistics that focuses on categorizing languages into structural similarities. This approach to grouping languages considers commonalities like word order, grammatical structure and phonological factors like consonants, vowels and syllable stress.
• morphological typology - Created by Friedrich and August von Schlegel, the morphological methodology is a particular linguistic typology that involves classifying languages based on the combination and style of morphemes within the language. The main two categories are analytic and synthetic languages.
Biological Typology Examples
Typologies are used to group living things for the purpose of biological study, as well as to make it easy for people to understand relationships and associations that exist among plants and animals that share traits in common.
• typology of living things - The system used to classify living things is a taxonomic classification system that groups life forms into categories based on common characteristics. This typology goes from broad to specific, starting with domain, then moving to kingdom, phylum, class, order, family, genus, and species.
• typology of vegetables - There are four primary vegetable families into which veggies can be classified. They are nightshades (peppers, tomatoes, eggplant, potatoes), brassicas (cabbage, mustard, kale, broccoli, cauliflower), legumes (peas, beans), and cucurbits (cucumbers, squash, melons).
Typologies Explaining Economic Factors
Typologies are commonly used in the world of economics. Certain geographic areas and industries can be classified based on how certain factors impact their economic success, as well as by the impact they have on the economy.
• farm structure typology - The United States Department of Agriculture (USDA) classifies farms by grouping them into a typology of four broad groups: small family farms, midsize family farms, large-scale family farms, and nonfamily farms. There are subcategories within a few of these groups.
• economic dependence typology - The USDA classifies all U.S. counties into a typology of categories based on industries that people in the area are dependent on in order to earn a living. There are seven categories in this typology: farming, government (federal or state), manufacturing, mining, recreation, and non-specialized.
Typology in Architecture
In architecture, typology involves using traits of buildings or spaces in order to classify them, as well as how architectural work is performed.
• taxonomy of architectural concepts - Architectural concepts can be grouped typology in the form of a taxonomy. Such a taxonomy can begin with an architectural concept, then can narrow to a cultural concept, mental concept, spatial concept, planning concept, and a design concept.
• typology in landscape architecture - There are several ways landscape architecture can be classified. One taxonomy includes seven groupings: cultivated expression, design as synthesis, ecological design, landscape analysis, plural design, spiritual landscapes, and synthesis.
Examples of Typology in Art
There are a number of typologies in the field of art, as works of art and artistic styles can be grouped or classified in many different ways. Any way that works of art can be grouped together based on similar characteristics represents a typology.
• photographic typology - Photographers can create their own photographic typology by shooting a collection of images with common traits, such as a similar structure or subject matter. For example, Ansel Adams is known for his collection of National Park photographs. This is one typology within his body of work.
• artistic periods - Artistic style and media have changed a lot over time, which is why works of art are often classified by period. A typology of art history might include Ancient, Medieval, Renaissance, Baroque, Neoclassical, Romantic, Realistic, and Modern.
Typology in Religion
There are numerous examples of typology associated with religious texts such as the Holy Bible, as well as in various religions of the world. The way a person approaches religion can also be expressed as a typology.
• religious belief typologies - There are many ways to classify religious beliefs into typologies. For example, some religions are monotheistic (belief in one God) while others are polytheistic (belief in multiple gods). There are also many different denominations, each of which can be considered part of a typology.
• updated religious typology - The Pew Research Center recently posited a new seven-part typology that groups people into types based on how religion impacts their lives. Their types are: Sunday Stalwarts, God-and Country Believers, Diversely Devout, Relaxed Religious, Spiritually Awake, Solidly Secular, and Religion Resisters.
Making Sense of Typology
Understanding typology is important if you wish to conduct academic research or applied research. It's also beneficial if you wish to use different systems of classification in order to understand how things relate to each other. To get a sense of how typology comes up in many fields of study, consider various natural ecosystem examples. Each category is a typology. Any time you group things together, such as organizing words into different parts of speech, you're using a typology.
|
<urn:uuid:fbab6c1e-7dba-4c36-b4ec-6b14787d1e3d>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.515625,
"fasttext_score": 0.2475413680076599,
"language": "en",
"language_score": 0.9243972301483154,
"url": "https://examples.yourdictionary.com/examples-of-typology.html"
}
|
January 1, 1946 - The Iron Curtain
By Em Williams
Iron Curtain
Winston Churchill was the Prime Minister of the United Kingdom from 1940 to 1945. After his failure to be reelected, he delivered a speech on March 5, 1946. This address is known as the “Iron Curtain” speech. Previously, the Soviet Union had expanded their sphere of influence to several neighboring countries. If this were to continue, the Soviet Union would quickly become an unstoppable force. In the early 1940s, the Americans had a passive stance in regard to interference with the Soviet Union. Winston Churchill delivered his speech to encourage the involvement of the Americans in alliance with the British against the Soviets. As he described, “From Stettin in the Baltic to Trieste in the Adriatic an iron curtain has descended across the continent”. Churchill was explaining that the only way to stop the spread of communism is active defiance from the Americans, since the British were not strong enough to fight alone. Winston Churchill’s Iron Curtain speech is an address with great cultural significance and lasting effects.
British Prime Minister Winston Churchill delivers a speech at Westminster College that addressed the Communist threat, and in which he uttered the now-famous phrase ‘Iron Curtain,’ Fulton, Missouri, March 5, 1946. (Photo by George Skadding/The LIFE Picture Collection/Getty Images)
Many people consider the Iron Curtain speech to be one of the pivotal events that made the Cold War inevitable. It not only rallied the support and interference of the Americans, but it also highlighted key tensions in Europe. Churchill used the metaphor of the “iron curtain” to make it seem like there is a mighty line dividing Europe down the center. He continued to use this motif to solidify his stance beyond the Iron Curtain speech itself. Churchill also used fear as a persuasion tactic by making a comparison to the Hitler before World War II. However, one of the potential problems of conflict at this time was the fact that multiple nations had weapons of mass destruction. If Churchill’s speech were to start a war with physical violence, nations could do about one thousand times more damage with a nuclear weapon than a traditional explosive. In America, Churchill’s leadership was widely respected. Churchill was ultimately one of the leading reasons the United States joined the North Atlantic Treaty Organization against the members of the Warsaw Pact.
Ultimately, Winston Churchill’s Iron Curtain speech had many significant effects throughout the United States along with the world. The speech is one of the turning points, often attributed as one of the primary causes of the Cold War. Naturally, many risks were possible due to the nature of the speech and the target of the potential alliance. The one primary outcome of the speech was how the United States ultimately joined NATO, meaning Churchill’s speech was successful.
Iron Curtain speech
“Churchill, Winston.” In Cold War Reference Library, edited by Richard C. Hanes, Sharon M. Hanes, and Lawrence W. Baker, 100-08. Vol. 3. Detroit, MI: UXL,
Gormly, James L. “Iron Curtain.” In America in the World, 1776 to the Present: A Supplement to the Dictionary of American History, edited by Edward J. Blum, 533-34. Vol. 1. Farmington Hills, MI: Charles Scribner’s Sons, 2016. https://link.gale.com/apps/doc/CX3630800270/UHIC?u=seve27129&sid=UHIC&xid=3be4233e.
“Iron Curtain Speech.” In The Cold War–1945-1991: Leaders and Other Important Figures in the United States and Western Europe. Detroit, MI: Gale, 1992. https://link.gale.com/apps/doc/BT1605203049/UHIC?u=seve27129&sid=UHIC&xid=1cdaad54.
|
<urn:uuid:80889dfe-c5aa-486b-9e23-df89e0dda672>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 4.125,
"fasttext_score": 0.51837158203125,
"language": "en",
"language_score": 0.9314479827880859,
"url": "https://severnhistoricalsociety.org/timeline/the-iron-curtain/"
}
|
cruise ships
Halt | May 4, 2021 | 0 Comments
What Is the Jones Act and How Does It Affect Cruise Ships?
Have you ever thought about taking a cruise visiting only ports in the United States? You’re out of luck unless you board a small-ship cruise line.
Why? The reason for this is a nineteenth-century law intended to protect US interests.
The Passenger Vessel Services Act of 1886 makes it illegal for foreign-registered ships to carry passengers directly between US ports. The Jones Act established as part of the Merchant Marine Act of 1920, incorporated much of the Passenger Vessel Services Act of 1886.
Regardless of the fact that many big cruise liners have their headquarters in the United States, all large cruise ships operating in US waters, with the exception of one, are registered in other countries.
Learn more about the Jones Act maritime law and how it has impacted the travel aboard cruise ships in this quick history and guide.
What Is the Jones Law?
The Jones Act, also known as the Merchant Marine Act of 1920, is a federal law passed to establish and sustain the merchant marine. It was warranted to boost commercial operations and create a naval auxiliary in war or national emergency.
The Jones Act mandates that goods be transported between US ports by US-flagged ships only.
The Passenger Vessel Services Act of 1886 is a cabotage-related piece of US legislation introduced into the Jones Maritime Law in 1920. Cabotage is where a transport operator from another country transports goods or passengers between two locations in the same country.
If you break the law, there is a hefty fine imposed. The fine is per passenger rather than per ship. So for many cruise ships which carry thousands of tourists, the bill may be substantial!
History of the Jones Act
Following World War I, the United States enacted the Jones Act to boost the shipping industry. The act was enacted to give Washington a monopoly on transportation to Alaska when the state had a thriving shipping industry. Despite the fact that the act benefited Jones’ representatives, it increased freight prices in other states and US colonies.
The US government grants conditional exceptions to Jones Act laws on many occasions. This is typically done after a natural disaster, such as a storm. They did this to increase the number of ships that can legally carry aid to a disaster-stricken area.
What Laws Should Cruise Ships Follow?
What Laws Should Cruise Ships Follow
If the itinerary starts and finishes in a US port, foreign-registered ships must meet Jones law requirements. These rules do not apply to cruises that start or finish in another country.
However, there are two requirements cruise lines operating foreign-flagged ships in US waters need to obey.
One is, if a cruise itinerary visits a US port during the trip, it must include a stop at a foreign port. Since 2016, the US government outlawed all foreign-registered cruises with no itinerary.
This is why Alaska cruises departing from Seattle call at Victoria, British Columbia. And, cruises between California ports and Hawaii call at Ensenada, Mexico.
The second is, if a cruise begins in one US port and ends in another, the itinerary must have a stop at a remote foreign port.
Violation of the Jones Law by Cruise Ships
Cruise lines will want to prevent infringing on the Jones Act. Fines imposed on a cruise line for thousands of passengers on a big ship will run into the millions of dollars! However, certain circumstances, make it difficult for a ship to make a scheduled international port stop. The two main ones are inclement weather and an abrupt port closing, but, there are others.
The Captain must make a reasonable attempt to make a port change if necessary. If this proves unlikely, US Customs and Border Patrol can give a Jones Act waiver. They can also mitigate penalties if the violation was not committed intentionally. That is why it is so important for a Captain of a cruise ship to learn more about the Jones Act.
What Cruise Ships Are Exempt from the Jones Act?
What Cruise Ships Are Exempt from the Jones Act
US-flagged cruise ships departing from US ports are permitted to tour other US ports without making a stop in a foreign port. However, there are certain requirements the ship and crew must follow to register in the United States:
• A US company must own the ship
• The ship’s construction must have taken place in the United States
• The crew must be entirely composed of United States nationals and permanent residents allowed to work in the United States
While several large cruise lines have their headquarters in the United States, if their ships are registered abroad, they must adhere to the Jones act maritime. The following large foreign-registered cruise ship is the only one allowed to operate.
The Pride of America
The Pride of America, operated by the Norwegian Cruise Line, is the world’s only big cruise ship that sails exclusively in Hawai’i. It offers year-round seven-day cruises that begin and finish in the United States, with no international ports of call. It can do so since it is a US-flagged vessel.
Pride of America is staffed mostly by Americans. The ship was partly constructed in the United States.
Construction was started in Mississippi, but completed in Germany. The US government granted a special exemption to allow the ship, which was mainly built in Germany, to be registered in the United States.
The Controversy Around the Jones Act
Although the landscape has changed dramatically since 1920, the Jones Act has remained constant. The once-famous US commercial shipbuilding industry is now extremely costly and technically redundant.
The Jones Act shipping fleet, which reached 257 ships in 1980, has dwindled to less than 100 vessels as cheaper modes of transportation are sought.
This aging fleet, which is inadequate to satisfy the needs of the world’s largest economy, also completely fails in its position as a naval aide. When the military requires naval assistance, Jones Act ships are seldom used.
By limiting the number of ships that can lawfully carry freight to Alaska, Hawaii, Puerto Rico, and other US territories that depend on imports, the Jones Act increases the cost of shipping.
Shipping companies acquire fewer vessels as businesses transport less freight by water. Reduced demand forces suppliers to create fewer ships, reducing merchant sailors’ employment opportunities.
In 2011, the House proposed a bill to amend Title 46 of the US Code. That was to permit foreign-registered cruise ships to operate in US waters without being subject to Jone’s act restrictions. The bill did not pass, and Jone’s law continues to be a source of contention among lawmakers, the cruise industry, and cruise enthusiasts.
Cruising the US Waters
The Jones Act is a hot-button topic. It is being tossed back and forth between economic ideologies that are fundamentally opposed. There are zealous proponents and adamant critics, each filled with statistics and figures.
The Jones Act has a section that is expressly applicable to cruise ships and their passengers. The Passenger Vessel Services Act, or PVSA, regulates ships that carry passengers as opposed to ships that carry freight.
In this understanding of Section 27 of the 1920 Jones Act, you will decide whether you support or oppose it.
If you find this article interesting surf our page for more informative articles.
|
<urn:uuid:87d32e0e-6502-47f3-817c-2299661ff192>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.53125,
"fasttext_score": 0.3603830933570862,
"language": "en",
"language_score": 0.9563267230987549,
"url": "https://www.halt.org/jones-act-and-how-does-it-affect-cruise-ships/"
}
|
Massacre in Semlin
Peter the Hermit departed Cologne with his following on around 20 April. He had a much larger following than Walter and it grew bigger as he passed through villages along the Danube River. By the time Peter arrived in Oedenburg, the gateway into Hungary, his force numbered more than 20,000 pilgrims. King Coloman must have forgiven the first wave of crusaders for the trouble they caused in Semlin, or else news of their attempted theft did not reach him. He granted Peter and his followers’ food, other supplies and safe passage through his kingdom on condition they would not pillage and commit murder.
All went well until they entered Semlin. Steven Runciman credited Peter the Hermit as being a genuinely pious and humble man; he sought to build friendly relations with the kings and bishops of Europe because he wanted safe passage for himself and for his followers. He did not, according to Runciman, want his followers to pillage and murder their way through the various villages. Unfortunately, in Semlin dispute over the sale of a pair of shoes escalated into a pitched battle in which Geoffrey Burel, a knight led an attack on the town, killing four thousand Hungarians.
Albert, a chronicler of the First Crusade, painted a much different picture of the events that transpired in Semlin. Word of what the Hungarians had done to several of Walter’s men, reached Peter at Oedenburg, but Peter refused to believe that fellow Christians would do such a thing to their own men until he “saw hanging from the walls the arms and spoils of the sixteen companions of Walter who had stayed behind a short time before, and whom the Hungarians had treacherously presumed to rob.” At the site of their clothes and arms, Peter “urged his companions to avenge their wrongs.”
They raised their banners high and attacked the Hungarians, letting loose a hail of arrows from their bows. The Hungarians, completely caught off guard and unprepared for battle, gathered their strongest knights — who numbered about seven thousand — but they were quickly overwhelmed by Peter’s far more numerical force. Four thousand Hungarians were massacred in that pitched battle, while Albert wrote, only one hundred pilgrims perished.
After their quick victory, Peter and his followers remained in the city for a few days where they gathered enough grain, sheep, cattle, horses and wine to feed and supply the entire army. Then Peter learnt that King Soloman was marching on Semlin with an army to avenge his slain people. Taking all their newly acquired supplies, Peter hastened with his followers to the Save River, but they found very few boats to carry them safely across the river. On the other side, Nicetas ordered his Pecheneg mercenaries to restrict the crusaders’ crossing to one area. Desperate to get away from the Hungarian king’s army, the crusaders repelled the Pecheneg mercenaries; they sank the boats that carried Pechenegs and slay those who had not drowned. Very few of Nicetas’ mercenaries escaped the wrath of Peter and his pilgrims. Furious and unstoppable, the crusaders descended upon Belgrade, a prosperous city in Bulgaria. There, they found the city abandoned. The townspeople, after undoubtedly hearing about the brutal massacre in Semlin, fled the city. They were wise to do that, for many–if not most–of them would have been slaughtered. Peter and his followers pillaged the city and then razed
The People’s Crusade
Nevertheless, Peter had amassed a great following. Historians estimate that his following was anywhere between 20,000 and 30,000 people, large enough to be considered an army. Today, Peter the Hermit’s expedition is widely known as the People’s Crusade.
The biggest challenge Peter faced with leading such a large army was how he was going to keep them all well fed throughout the entire journey. There were very few districts in Europe that had enough food to feed such a large group of pilgrims, so the only way he was going to keep them fed was to keep them moving. Though, the district of Cologne lay strategically near the Rhine River so the land in that area was more fertile. Peter assumed that the townspeople of Cologne would have enough food to feed him and his following. That was probably why he decided to stay there for a number of days. He also wanted to preach to the Germans with the intent to recruit more nobles to his crusade.
Peter was successful: the German nobles, Count Hugh of Tubingen, Count Henry of Schwarzenberg, Walter of Tech, Count Emich of Lusingen, Gottchalk and the three sons of the count of Zimmern, all inspired by Peter’s preaching, made their crusader vows.
However, not everyone left Cologne when Peter left. Walter Sans Avoir grew impatient and so he left Cologne, taking a few thousand of Peter’s followers with him, all of them probably knights. They marched alongside the great Rhine and Neckar rivers, then down the Danube, arriving in Hungary in early May of 1096. “When his (Walter’s) intention and the reason for his taking this journey became known to Lord Coloman, most Christian king of Hungary, he was kindly received and was given peaceful transit across the entire realm, with permission to trade. And so without giving offence, and without being attacked, he set out even to Belgrade a Bulgarian city, passing over to MaleviUa, where the realm of the kingdom of Hungary ends. Thence he peacefully crossed the Morava (Save) river,” wrote Albert, a chronicler of the First Crusade.
The moment they set foot in Semlin, discipline in Walter’s small army of crusaders disintegrated. As sixteen men attempted to rob a bazaar, they were caught in the act by the Hungarians. They were consequently stripped of all their arms and clothes and sent across the Save river naked. The Hungarians hung their clothes on the town wall as a warning to all.
Conditions for the crusaders deteriorated even more once they entered Belgrade. Since it was mid spring, the harvest had not yet been gathered, so the townspeople could not feed Walter’s army. They were probably just as suspicious of these foreigners as was their king and his military commanders. In any case, they forbade the sale of anything to Walter and the crusaders. Furious, Walter and his troops pillaged the countryside, stealing herds of cattle and sheep. In the process, the crusaders got separated from each other, so when the Bulgarians counter-attacked, they were quickly scattered and many of Walter’s men were massacred.
Walter fled with what remained of his army to Nish. “There he found the duke and prince of the land and reported to him the injury and damage which had been done him. From the duke he obtained justice for all; nay, more, in reconciliation the duke bestowed upon him arms and money, and the same lord of the land gave him peaceful conduct through the cities of Bulgaria, Sofia, Philippopolis, and Adrianople, and also license to trade.” They arrived at the gates of Constantinople in the middle of July and were received well by the Emperor Alexius. There, they waited for the arrival of Peter the Hermit and his much larger force.
Bernard of Clairvaux: Preacher of the Second Crusade
This is a guest article by Kathryn Helstrom.
Peter the Hermit: Charismatic Preacher
Everyone who filled the field in Clermont on that crisp day in late November made the vow to save Byzantium and restore Jerusalem to Christian rule. But how, in a time when there was no such thing as TV, computers, internet or printing press, and no advocacy for mass literacy, did Urban’s cry for Holy War travel so far so fast?
The people went home and told their families’ what their beloved Pope had just commanded them to do. Hence, Urban’s message was spread via word of mouth. However, there was one man who would help Urban spread the message far and wide: Peter the Hermit.
There is very little known about Peter’s background, so there is some historical debate as to whether he was born into nobility or poverty. According to Barbara Hutton, a scholar of the past, Peter once served as a soldier under Eustace de Bouillon, father of Godfrey de Bouillon. Peter married a lady of rank, but did not love her, so he chose to live his life in solidarity confinement as a means to end the marriage. Daniel Goodsell, on the other hand, suggested that Peter came from a poor family.
Regardless of Peter’s background, he possessed enough passion, imagination, reverence and charisma to move mountains. “He was small in stature and his external appearance contemptible,” William of Tyre wrote: Peter the Hermit wore a woolen tunic that had no sleeves and a coarse brown tunic overtop. He lived only on fish and wine, and traveled from village to village on top of a mule. However, “greater valor ruled in his slight frame. For he was sharp witted, his glance was bright and captivating, and he spoke with ease and eloquence.”
Historians of an earlier age believed that it was Peter the Hermit who prompted and inspired Pope Urban to initiate the First Crusade. Historians of today, though, have disregarded this belief, choosing instead to believe that it was Pope Urban who was the sole initiator of the First Crusade. Even though Urban was the perpetrator of this momentous historical event, Peter the Hermit’s involvement in the preaching of the Holy War should not be undermined.
It is quite possible that he travelled throughout France and preached Holy War prior to Urban’s speech at Clermont. Regardless, two things are for certain: whether Peter preached the crusade before Clermont or not, Pope Urban did sanction him to spread the message and Peter appealed to the commoners. He travelled on his mule from village to village, preaching Holy War, mimicking Urban in style and charisma. The reason he appealed so strongly to the commoners was because he addressed their needs. If they should take up the cross, God would forgive all their sins and bless them. Those who should die on the road to Jerusalem would look forward to spending the rest of eternity with Christ in Heaven. Those who should survive would reap the rewards, for the land in the east ran with milk and honey. That was what Peter probably told them anyway.
The people believed Peter because they wanted some kind of relief. Life in eleventh-century Europe wasn’t kind to peasants and laymen. The famine of 1094-5 left them starving and, possibly in some cases, on the brink of death. To make matters worse, the commoners were constantly caught in the cross-fire of warring lords; their lords were unable (or unwilling) to protect them. Thus, the Holy War provided them with a one-way ticket out of Europe.
To the commoners, Peter was the embodiment of true Christianity: he gave liberally, kept nothing for himself and took great pleasure in abstinence. He even mended broken marriages, restoring husbands to their wives. Given everything Peter did, it’s no wonder why people rallied to his side and took the cross. They even inspired family, relatives, friends and acquaintances to join them just as their wealthier counterparts had done. The message spread fast until every corner of Europe heard the call to Holy War and responded to it.
Pope Urban Sets The Crusading Era in Motion
Pope Urban II was the man who set the crusading era in motion. However, did he truly expect peasants and labourers to take up the cross and fight the Muslims alongside the most wealthy, powerful Lords of the land, and other highly skilled soldiers? Many historians maintain the belief that Pope Urban did in fact urge everyone, regardless of rank, to take part in the crusade. Urban’s very words as recorded by Robert the Monk: ‘And we do not command or advise that the old or feeble, or those unfit for bearing arms, undertake this journey; nor ought women to set out at all, without their husbands or brothers or legal guardians. For such are more of a hindrance than aid, more of a burden than advantage…’ implies that Pope Urban addressed only the aristocracy and knightly class to make the armed pilgrimage. Though, Robert’s account was written in around 1116, twenty-one years after Urban’s speech at Clermont.
Regardless of Pope Urban’s real intentions, he inspired tens of thousands of men, women and even children to take up the cross. Peace reigned and every human mind, how great or simple, was renewed with passion, hope and a sense of purpose. Everywhere, knights’ and princes’ swords were blessed by their priests with these words: “Take this sword and these arms in the name of the Father, the Son and the Holy Ghost! May they and it serve you in this good cause, but never may they shed innocent blood!”
Entire families abandoned their professions so they could prepare for the long journey to the Holy Land. “The Welshman left his Hunting, the Dane his drinking party, and the Norwegian his raw fish–all eager to join the expedition to the Holy Land,” said William of Malmesburry.
One reason why Urban had managed to gain tremendous support from kings, nobles and peasants was because his speech addressed the mentality of the time. Eleventh century Christianity was extremely black and white. King, noble and peasant alike lived in perpetual fear of sin. They were surrounded by sin. Failure to repent would lead to an eternity of excruciating suffering. But repentance lead to the promise of eternal salvation and peace with Christ in heaven. People were continually seeking perfection, closeness to God and absolution from any and all sins they committed.
God and Church were one and Popes believed that they were descendents of St. Peter; they had been given the keys to heaven. They appointed other men (clergy) to do God’s will on earth. The Medieval Catholic Church upheld the firm belief that it was up to God’s disciples to feed the people with God’s word, while requiring the people, including kings, to submit entirely to the teachings of the Church. In order to seek forgiveness, one must seek out a priest or bishop to confess to. In the eleventh century, the idea of a ‘personal relationship with God’ did not exist. People took the pope’s word as the truth and based their faith on his teachings.
The Rise of Islam
To fully understand the reasoning behind Pope Urban’s call to Holy War in 1095, one must understand the historical events that took place in the centuries leading up to the late eleventh century. Those historical events were essentially the rise of Islam.
Islam was born in around 610 AD when a man named Muhammad started receiving revelations from God through the Archangel Gabriel. Muhammad bears much resemblance to Jesus in that he was from a poor family and he was also illiterate.
After he started receiving these revelations, Muhammad had his family and a few others converted to Islam, but the people of Mecca clung to Zoroastrianism — the ancient, pagan religion Mecca adhered to. Like Jesus, Muhammad was forced to flee his hometown (which was Mecca) and seek refuge in a neighboring city. For Muhammad, that neighboring city was Medina. Unlike Jesus who traversed the Holy Land peacefully, preaching the word of God and performing miracles, Muhammad took up the sword and waged war against Mecca. The war was long and bloody, but it finally fell to Muhammad and his followers in 632, just a few years before Muhammad’s death.
Islam took root in Medina during Muhammad’s life, but much more so after his death thanks to his ardent, loyal followers.
Caliph and common Arab alike believed that Islam was the one and only true religion; the only path to salvation. Every man — Islam regarded women as second class citizens and still does to this day — must submit themselves to the will of God (Allah). This ultimately resulted in an insatiable desire to unite the entire world under the banner of Islam.
From the mid seventh century until the early eighth century, the Muslim armies were unconquerable. Within the second half of the seventh century, Iraq, Syria, Egypt, most of Persia, and the entire north coast of Africa fell to the Muslims. Then, in 711, Islamic forces invaded the Iberian Peninsula which is Spain and within two decades, they conquered most of Iberia.
The booty and slaves captured from conquered territory brought the Muslims immense wealth. They were also united under one Caliph and their armies, organized. That is what enabled them to keep on expanding. They would have taken over Europe—the whole world for that matter –had not Charles “The Hammer” Martel roundly defeated them at the Battle of Poitiers in 732 AD. Badly beaten and significantly mowed down in size, the Muslim army retreated back to Spain and never again set foot on French soil.
What happened to Christians and Jews in conquered territories?
The Treatment of Christians Under Muslim Rule Deteriorated
Christians were never treated well under Muslim domination, but under the rule of Caliph al-Hakim in the early eleventh century, they faced severe persecution.
When pilgrims and other Christians living within the boundaries of the Byzantine Empire heard of al-Hakim’s persecution of Christians, they were horrified. Stories inevitably found their way back west and fuelled Christian hatred of the Muslims, especially among the clergy.
“Let all Christians know that news has come from the east to the seat of the apostles that the church of the Holy Sepulcher has been destroyed from roof to foundations at the impious hands of the pagans…With the Lord’s help we intend to kill all these enemies and to restore and Redeemer’s Holy Sepulcher,” wrote Pope Sergius IV.
However, it wouldn’t be until the end of the eleventh century that this call to arms, call for Holy War, would take on more vigor and intensity. Only one man would set Christendom on fire with crusading zeal: Pope Urban II.
Pope Urban Preaches Holy War: November 1095
When Pope Urban II got a hold of the Byzantine Emperor’s letter — Alexius Comnenus had intended for the letter to be passed on to him — he took matters into his own hands. Not only did he hate the Muslims, Urban shared the same deep rooted fear as did Emperor Alexius: Should military help not arrive in Constantinople soon enough, Byzantium, the gateway to the Holy Land, would fall to the Muslims. Pope Urban cared for the Eastern Christians and he wanted to help preserve their empire, but he was also a man of high ambition. So, it was very likely that his fear stemmed from the fact that the Muslims posed to threaten his papal expansion, the ultimate goal he held onto for several years.
Pope Urban inherited a mess when he assumed the papal throne in 1088. The papacy was embroiled in a power struggle with the German Emperor. This conflict was so bitter that it took Urban six years to reassert papal authority over Rome’s Lateran palace. In that time, Urban created a series of policies that were non-confrontational, designed to persuade the German Emperor, Henry IV to submit to Rome without force. Even those reforms did not succeed over night. Even when they did, Urban’s divine right to act as head of the Latin Church and spiritual overlord of every Christian in western Europe was still far from his reach.
Urban realized that his ‘Crusade’ — then termed as holy war or armed pilgrimage — would improve relations with the Greek church, which would enable him to expand papal authority into the eastern realm. He also believed that a crusade would unite all of Western Europe under one cause: to fight the Muslims in God’s Holy name. Only then could Urban’s goal become a reality.
In order to set his holy war in motion, Pope Urban needed to find a method to persuade all of Christendom to make the armed pilgrimage. He had to somehow reconcile murder, a deadly sin, with God’s divine will. However, Urban didn’t worry too much about that because he knew just the right thing to say and how to say it.
Several versions of Pope Urban’s speech have been recorded and passed down through the generations. This version was written by Robert the Monk, Chronicler of the First Crusade.
But if you are hindered by love of children, parents and wives, remember what the Lord says in the Gospel, “He that loveth father or mother more than me, is not worthy of me.” “Every one that hath forsaken houses, or brethren, or sisters, or father, or mother, or wife, or children, or lands for my name’s sake shall receive an hundredfold and shall inherit everlasting life.”
Enter upon the road to the Holy Sepulcher; wrest that land from the wicked race, and subject it to yourselves. That land which as the Scripture says “floweth with milk and honey,” was given by God into the possession of the children of Israel Jerusalem is the navel of the world; the land is fruitful above others, like another paradise of delights. This the Redeemer of the human race has made illustrious by His advent, has beautified by residence, has consecrated by suffering, has redeemed by death, has glorified by burial.
The Byzantine Empire on The Brink of Destruction
News of al-Hakim’s ruthless persecution of Christians wasn’t the sole event that triggered hatred in the west. The Byzantine Empire, in the eleventh century, was on the brink of destruction. In the 1040s, Turkish warriors migrated from the steppes of central Asia and conquered Persia, then invaded Armenia and Iraq, and conquered Baghdad in the year of 1055.
The Turkish invasions jeopardized the safety of pilgrims and threatened to sever Europe’s ties with Jerusalem. To make matters worse, Byzantium was severely weakened by the Bubonic Plague. Many people had died, leaving the emperor unable to protect the pilgrims and his people from Muslim raids.
In the summer of 1071 Emperor Romanus IV Diogenes decisively chose to fight back with two goals in mind: recapture all territory lost to the Turks and crush Sultan Alp-Arslan and his armies for good. However, it was not so. The Emperor’s army numbered approximately 40,000 troops, but Caliph Alp-Arslan’s army held the upper hand in strategy. At the battle of Manzikert, Emperor Romanus was captured and his armies, defeated.
Romanus was not held captive for long, but shortly after he returned to his people, he was “deposed, and then blinded and finally killed after great torture and torment.”
When Alexius I Comnenus took the imperial throne in 1081, only a few coastal towns in the north belonged to the Byzantine Empire. Not only were his coffers empty, Alexius was bombarded with perpetual threats from the Turks. At the same time, ferocious Pecheneg and Cuman nomads from the Russian steppes raided the Danube frontier. It was at this crucial moment that Emperor Alexius decided he needed help.
In 1093, Alexius wrote a letter to Robert, Count of Flanders, requesting military aid against the Seljuk Turks. In his letter, Alexius wrote of all the horrible deeds the Seljuk Turks had committed. Emperor Alexius feared — no, he knew — that all of Byzantium would fall to the Turks and Christianity in the East would be stamped out. These fears weren’t imagined; they were very real, and they were certainly spelled out to Count Robert.
Alexius also took the extra measure to provide Count Robert with other reasons why Robert should send military aid to Constantinople:
“Remember that you will find all those treasures and also the most beautiful women of the Orient. The incomparable beauty of the Greek women would seem to be a sufficient reason to attract the armies of the Franks,” Alexius wrote.
Beautiful women! That would have provided any man with enough incentive to travel a long distance and fight in a foreign land. However, Emperor Alexius needed only a small army of barons and their strongest knights to fight the Turks. That’s what he wanted. He had not anticipated the enormous armed force that would arrive at the shores of Constantinople three years later.
Sources Used:
Alexius I Comnenus: Byzantine Emperor:
The Battle of Manzikert (1071 A.D.):
|
<urn:uuid:da8742e3-0992-4b9b-9a7e-7936397314f6>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.05288976430892944,
"language": "en",
"language_score": 0.9792830944061279,
"url": "https://crusadesandcrusaderscom.wordpress.com/"
}
|
FL: HIV, 1 unitPage 5 of 11
3. Transmission of HIV
HIV is a relatively fragile virus that is not spread by casual contact. HIV is not easy to “catch”—it must be acquired. In order for HIV to be transmitted, three conditions must occur:
• There must be an HIV source.
• There must be a sufficient dose of virus.
• There must be access to the bloodstream of another person.
One of the predictors of the infectious level of an HIV-positive person is viral load—how much HIV is present in the bloodstream. Studies show a clear connection between higher viral load in the blood and increased transmissibility of HIV.
HIV is transmitted through:
• Unprotected anal, vaginal, and oral intercourse
• Sharing needles or other injection equipment
• A mother passing the virus to her baby either before or during birth
• An infected woman breastfeeding her infant
• Accidental needlestick injuries, or infected bodily fluid coming into contact with the broken skin or mucous membranes of another person (as with healthcare workers)
• A transfusion prior to 1986 of HIV-infected blood or blood products
In extremely rare cases, HIV can be transmitted by sharing razors or toothbrushes, if infected blood from one person was deposited on the toothbrush or razor and the blood entered the bloodstream of another person.
In settings such as hospital operating rooms, other fluids—cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid, amniotic fluid—may be considered infectious if the source is HIV-positive. These fluids are generally not found outside the hospital setting. Therefore, the most common body fluids considered potentially infectious for HIV are blood, semen, vaginal secretions, and breast milk.
HIV transmission may occur during practices such as tattooing, blood-sharing activities such as “blood brother” rituals or any other type of ritualistic ceremonies where blood is exchanged, or when unsterilized equipment contaminated with blood is shared. HIV transmission may also occur in occupational settings.
Hepatitis Co-Infection
Many people who become infected with HIV from injecting drug use are already infected with hepatitis C (HCV). Some estimate that 40% of HIV-infected people in the United States are also infected with HCV. People who are co-infected with both viruses and have immune system impairment may progress faster to serious, chronic, or fatal liver damage. Most new HCV infections in the United States are among injection drug users. The majority of hemophiliacs who received blood products contaminated with HIV also are infected with HCV.
Treating HIV in someone with HCV may be complicated because many of the medicines that are used to treat HIV may damage the liver; however, treatment for co-infection is possible in some cases with close physician supervision.
People Unaware of Their Positive Status
People who are infected with HIV come from all races, countries, sexual orientations, genders, and income levels. Globally, most of the people who are infected with HIV have not been tested and are unaware that they are living with the virus. The CDC estimates that, in 2006, 21% of those in the United States who had HIV were unaware that they were living with the virus. This is a decline from the 25% measured in 2003 and is a positive sign because research shows that most individuals who know they are infected with HIV will reduce behaviors that could transmit the virus (CDC, 2010).
It is important to note that the great majority of people with HIV infection do not transmit HIV to others. The CDC estimates that in 2006 there were 5 transmissions per 100 people living with HIV infection. This means that at least 95% of those living with HIV infection did not transmit the virus to others that year. This represents an 89% decline in the estimated rate of transmission since the peak level of new infections in the mid-1980s. It is believed that the decline is due to effective prevention efforts and the availability of improved testing and treatments for HIV (CDC, 2010).
Pregnant Women
An HIV-infected woman may transmit the virus to her baby during pregnancy, during the birth process, or following pregnancy by breastfeeding. One of the predictors of how infectious the woman will be to her baby is her viral load (how much HIV is present in her bloodstream). Women with new or recent infections or people in the later stages of AIDS tend to have higher viral loads and may be more infectious.
HIV is transmitted from an HIV-infected woman to her baby in about 25% of pregnancies if intervention with antiretroviral medications does not occur. The perinatal transmission rate has dropped dramatically in the United States due to the widespread use of the drug AZT by HIV-infected pregnant women. When a woman’s health is monitored closely and she receives a combination of antiretroviral therapies during pregnancy, the risk of HIV transmission to the newborn drops below 2%.
In some pregnancies, cesarean section (C-section) may be recommended to reduce the risk of transmission from mother to baby. Advice about medications and C-section should be given on an individual basis by a medical provider with experience in treating HIV-positive pregnant women. Most states, including Florida, require pregnant women to be counseled regarding risks of HIV and be offered voluntary HIV testing.
|
<urn:uuid:8b510ef4-56cd-4313-863a-8028b7178e54>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.765625,
"fasttext_score": 0.03279608488082886,
"language": "en",
"language_score": 0.9524387121200562,
"url": "https://www.atrainceu.com/content/3-transmission-hiv"
}
|
Edit Photo
Water clock Science Project
Building a Water ClockBernard Gitton's Time-Flow clock
Luna04 / CC-BY-SA-3.0, via Wikimedia Commons
This activity should follow student encounters with more simple systems, such as pencils, scissors, etc. In this activity, students will begin to examine more closely the interactions between the parts of a system. The main goal of having students learn about systems is not to have them talk about systems in abstract terms, but to enhance their ability to attend to various aspects of particular systems in attempting to understand or deal with the whole system.
Begin by letting students view This Week's WOW: Water Clock, a video of the largest water clock in North America, on display at the Children's Museum of Indianapolis. Students should jot down and describe some of the parts that make up the water clock.
As they read, ask students to write down the answers to these questions:
• What are the parts of a water clock?
• (An oscillator [the pendulum], a frequency divider, a minute counter [the minute discs], and an hour counter [the hour balls]. Water from a pump in the basement, just below the clock, is pumped through a pipe running up the middle of the clock into a reservoir at the top. The water then drips down onto a scoop at the top which is connected to the green, swinging pendulum. The pendulum causes the scoop to dump the water into a series of siphons. The siphons fill and empty into the minutes' globes. A siphon is a tube in an inverted "U" shape which causes the solution to flow up, without pumps, powered by the fall of the liquid as it flows down the tube under the pull of gravity.)
• What is it designed to do?
• What advantage does it have over other devices such as sundials?
• (It could be used at night as well as in daylight.)
• What is the largest problem associated with water clocks?
• (The rate of flow of water is very difficult to control accurately.)
• Discuss the answers with the class.
How A Water Clock Works
In the first part of the activity, the class will investigate how a water clock works and the effect of one of its variables on its ability to be an accurate timepiece.
Tell students: Early water clocks were stone vessels with sloping sides that allowed water to drip at a nearly constant rate from a small hole near the bottom. Other water clocks were bowl-shaped containers that slowly filled with water at a constant rate. Markings on the inside surfaces measured the passage of time as the water level rose on the inside of the bowl, a result of its slowly sinking. We're going to use a soft drink bottle to make a similar device.
Ask students to select what they consider to be the most important parts of the device.
Do the following as a teacher-led exploration:
1. Use the pin to make a very small hole in the bottom or close to the bottom of the bottle. A hole smaller than the diameter of the pin is desirable. Let the students examine the hole.
2. Holding a finger over the hole, fill the bottle with water to a level just below the shoulder where it begins to have a smaller diameter. Mark this level on the outside of the bottle. Measure the time required for 100 ml (+/- 0.5 ml) of water to run or drip out of the bottle. Repeat the experiment with the starting water level about halfway up the bottle and with the starting water level very low in the bottle. Plot the times as a function of the distance the starting water level was above the hole in the bottle.
Discuss the results with the class using questions such as the following:
Source: sciencenetlinks.com
Water Clock project for Physics
Water Clock project for Physics
Science Project
Science Project
Water Clock
Water Clock
Share this Post
Related posts
Water clock Project
Water clock Project
OCTOBER 27, 2021
The purpose is to have students come together and work to build a water clock as a symbol of sustainability. In addition…
Read More
Water clocks how they work
Water clocks how they work
OCTOBER 27, 2021
How a Pendulum Works: A pendulum is made up of a string or solid rod with a weight attached to the end. Pendulums are designed…
Read More
|
<urn:uuid:702d08c4-0b16-47c6-b1b5-c3bf3172b0d0>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 4.0625,
"fasttext_score": 0.03242582082748413,
"language": "en",
"language_score": 0.9438648819923401,
"url": "http://www.thecoalminetour.com/WaterClock/water-clock-science-project"
}
|
Say we have the the IP address
Anyone could say the following:
It just represents a normal network:
Or it is a subnet because normally this IP address is in the class A range,so that is 2^16 subnetworks
Or even,perhaps it is a supernet(not sure about this one(!))
How do we tell those apart?
• I would understand it to mean "the address is and the mask is"
– jonathanjo
May 2 '19 at 13:11
• Everything you wanted to know about IPv4 addressing is in this answer.
– Ron Maupin
May 2 '19 at 14:16
– Ron Maupin
Dec 15 '19 at 2:43
IP address classes have been obsolete since before you were born. Subnet and supernet are in relation to other networks. So is a subnet of, but a supernet of
Because address classes are no longer used, there aren't different types of masks. A network mask (also commonly called a subnet mask) simply defines the network and host portions of the address.
Also, the concept of "subnet bits" or "subnet ID" is similarly obsolete.
• If we had this address: , then how would i know what the previous mask was?It could be /16 so the subnet id is 9 bits ,or, /24 and so the subnet id was given just one bit.Can you really distinguish the original mask?
– Some1
May 2 '19 at 10:50
• 3
There is no 'previous mask' or 'original mask' concept.
– Teun Vink
May 2 '19 at 11:29
• 3
Just to add to the confusion, the term "subnet" is also used generally for any network segment.
– Ron Trunk
May 2 '19 at 12:30
Your Answer
|
<urn:uuid:09380a4e-dbb9-4dfb-b643-5153e6199188>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5,
"fasttext_score": 0.6879281997680664,
"language": "en",
"language_score": 0.9428415894508362,
"url": "https://networkengineering.stackexchange.com/questions/58855/how-to-tell-apart-the-type-of-the-masksubnet-supernet-net-mask"
}
|
Slide 1: What are the faint linear opacities (3 are arrowed) on this AP chest X-ray called? Chest x-ray shown with arrows pointing to peripheral area of the left lung.
Slide 2: These are called Kerley B lines or septal lines. What are they and why do they occur? To understand septal lines, we have to learn about the secondary pulmonary lobule, a polygonal structure that makes up the smallest unit of lung completely surrounded by connective tissue.
Slide 3: Anatomy of the secondary pulmonary lobule and etiology of septal lines. Graphic showing pulmonary lobule. Lymphatics (green) and pulmonary venules (red) are embedded in peripheral connective tissue (black). The pulmonary arteriole (blue) and bronchiole (grey) are the centrilobular structures. Alveolar sacs arranged around centrilobular structures. The most common etiology for septal lines is pulmonary edema, but anything that causes (1) lymphatic distension (e.g. lymph-angitic carcinomatosis) or (2) proliferation of connective tissue (e.g. pulmonary fibrosis) can create septal lines.
Slide 4: As you can see here (CT scan shown), normal septae are hard to see. Check out these images, both from a patient in heart failure. If septal lymphatics get distended, the polygonal secondary lobule (red arrows) becomes evident. CT scan showing central dots (red circle), which are arterioles.
Tags: , , , , , , , ,
|
<urn:uuid:6576063a-edb2-489e-8d68-d71e1e22f89a>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.78125,
"fasttext_score": 0.9658951163291931,
"language": "en",
"language_score": 0.8786147236824036,
"url": "https://www.coreimpodcast.com/2020/11/03/what-are-the-faint-linear-opacities-on-this-ap-chest-x-ray-called/"
}
|
Spanish/Lesson 6
From Wikibooks, open books for an open world
Jump to navigation Jump to search
Grammar - Object Pronouns[edit | edit source]
Direct Object Pronouns[edit | edit source]
El chico come la manzana.
Él la come.
The boy eats the apple .
He eats it .
The following table shows the six types of direct object pronouns:
Subject Object English
yo me me
te you
él lo him/it
ella la her/it
usted lo/la you
nosotros nos us, we
vosotros os you (plural)
ellos los them (masculine)
ellas las them (feminine)
ustedes los/las you
In spanish tú is used for informal situations, and usted must be used when a formal treatment is needed.
Indirect Object Pronouns[edit | edit source]
An indirect object is an object that would be asked for with To whom...? or From whom...?. It is called indirect because it occurs usually together with a direct object which is affected directly by the action:
La mujer da una manzana al chico.
La mujer le da una manzana.
The woman gives an apple to the boy .
The woman gives him an apple.
The apple is given by the woman (direct). The boy gets the given apple (indirect - depends on the apple being given).
Subject Indirect Object English
yo me to/from me
te to/from you
él/ella/usted le to/from him/her/you
nosotros/nosotras nos to/from us
vosotros/vosotras os to/from you
ellos/ellas/ustedes les to/from them/you
Position Of Object Pronouns (Double Object Pronouns)[edit | edit source]
Te compro una bicicleta .
Te la compro.
I buy you a bike.
I buy it for you.
El profesor le da unos libros.
El profesor se los da.
The professor gives her the books.
The professor gives them to her.
Carmen puede cantar el himno nacional.
Carmen puede cantarlo. or Carmen lo puede cantar.
Carmen can sing the national anthem.
Carmen can sing it.
Quiero mostrarte una casa.
Quiero mostrártela.
I want to show you a house.
I want to show it to you.
Exercise:Object Pronouns
Vocabulario (Vocabulary) - La comida (The food)[edit | edit source]
Las comidas The meals
el desayuno breakfast
desayunar, tomar el desayuno to have breakfast
el almuerzo lunch
almorzar to have lunch
la cena dinner
cenar to have dinner
la comida food, meal
comer to eat
Las comidas The meals
el desayuno breakfast
desayunar, tomar el desayuno to have breakfast
la comida (el almuerzo) lunch, main meal
comer (almorzar) to eat, to lunch
la cena dinner
cenar to have dinner
Las comidas The meals
el desayuno breakfast
desayunar, tomar el desayuno to have breakfast
el almuerzo lunch
almorzar to have lunch
la comida (la cena) dinner, main meal
comer (cenar) to eat, to have dinner
Instead of saying desayuno, comida y cena (Spain) or desayuno, almuerzo y comida (Chile, Colombia), it's safer to say desayuno, almuerzo y cena.
The word comida has several meanings
• food Me gusta la comida mexicana
• meal El desayuno es la principal comida del día
• lunch La comida es a las 2 PM
• dinner La comida es a las 9 PM
Las Frutas Fruits
la banana banana
el plátano (Spain, Chile, Perú)
el banano
la cereza cherry
la guinda
el damasco apricot
el albaricoque (Spain)
el durazno (Sp. Am) peach
el melocotón (Spain)
la fresa strawberry
la frutilla (Argentina, Chile, Uruguay)
el kiwi kiwi fruit
la manzana apple
la naranja orange
la pera pear
la piña pineapple
el ananá
la uva grape
la ciruela plum
Las Verduras Vegetables
la cebolla onion
la lechuga lettuce
la espinaca spinach
la papa (Sp. Am.) potato
la patata (Spain)
el pepino cucumber
el aguacate avocado
la palta (Argentina, Chile, Uruguay)
el tomate tomato
la zanahoria carrot
el zapallo (Argentina, Chile, Uruguay) pumpkin, squash
la calabaza (Spain)
los porotos (Argentina, Chile, Uruguay) beans
los frijoles (Mexico)
las alubias (Spain)
las caraotas
• Legumbres means the same thing as verduras (vegetables).
|
<urn:uuid:bff20e4b-e8bb-4612-b0f8-20308b290d95>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.71875,
"fasttext_score": 0.12690460681915283,
"language": "en",
"language_score": 0.6918026208877563,
"url": "https://en.wikibooks.org/wiki/Spanish/Lesson_6"
}
|
How Far Can You Jump?
This How Far Can You Jump? lesson plan also includes:
Students estimate the distance of student's broad jumps. This activity can take place in the block center with a small group of students. They are explained that they are going to jump from a starting point (marked with the masking tape), keeping both feet together. Students are asked how to determine how far each person can jump?
3 Views 7 Downloads
Classroom Considerations
|
<urn:uuid:5a684aba-b87a-4bcd-9bb2-9df22f11c4bf>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.515625,
"fasttext_score": 0.5874762535095215,
"language": "en",
"language_score": 0.932289719581604,
"url": "https://www.lessonplanet.com/teachers/how-far-can-you-jump"
}
|
From Cunnan
Revision as of 13:03, 11 July 2007 by Sarah Van Der Goes (talk | contribs) (spelling)
Jump to navigationJump to search
A buckle is a fastener that is typically used to secure a belt or a strap. They frequently have tongues and some also have throat plates running back from the buckle along the belt. Historically buckles could be made of bone, brass, bronze, silver and other metals. A single buckle could be be made of a combination of these materials, such as Viking buckles of copper alloy with iron tongues.
Softer metals do not function well in high load areas as they bend.
A wide variety of buckle shapes existed and there are examples of tongued single (one loop) buckles dating to ancient Greece. Double (two loops on either side of a central bar) buckles existed from at least the medieval era.
They could be highly decorative and smaller buckles appear on shoes from the mid-14th century.
The buckle is used as a heraldic charge, as evidenced in the Manesse Codex.
|
<urn:uuid:60e95688-6d83-4b5b-9d3a-e02f8823c8a3>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.06905949115753174,
"language": "en",
"language_score": 0.9723976254463196,
"url": "https://cunnan.lochac.sca.org/index.php?title=Buckle&oldid=33694"
}
|
Bats don’t have to learn the speed of sound – they’re born knowing it
A Kuhl’s pipistrelle in flight
AGAMI Photo Agency / Alamy
Bats are born knowing the speed of sound. This may not be shocking, as they rely on echolocation to find food avoid crashing into trees in the dark. But unlike birds that learn their songs, or lions that learn to hunt, bats seem to be born knowing how to echolocate.
Bats make high-pitched calls that reflect off distant objects, then they translate the time until the echo returns into some measure of distance. Depending on air temperature, sound can move faster or slower, it is a reasonable expectation that bats would accommodate for this.
To see whether bats can adjust their echolocation to accommodate changes in the speed of sound, Eran Amichai Yossi Yovel at Tel Aviv University in Israel trained eight adult Kuhl’s pipistrelle bats (Pipistrellus kuhlii) to fly to a perch within a chamber pumped full of oxygen helium. Because helium is less dense than other atmospheric gases, sound travels faster through it.
The helium interfered with the bats’ echolocation timing caused them to aim short of the perch. At first, this was expected, but the adult bats never learned to adjust.
“We were surprised by the results. Honestly, we didn’t trust them at first,” says Amichai, now at Dartmouth College in New Hampshire.
Amichai Yovel then tried the experiment with pups instead of adults. They hand-reared 11 bats, raising half of them from birth in the helium-enriched chamber. When the bats were old enough to fly, Amichai trained the pups to fly to the perch like the adults. Still, despite the environment the pups were raised in, neither group could accurately sense the distance to the perch in the helium environment.
Both experiments indicate that bats have a rigid, innate reference for the speed of sound. The team says they expect this to be the same in all bats, as the brain structures involved in echolocation are similar across species.
Because it is such a crucial part of the way the bat understands its world, Yovel says, it is possible that an innate sense of time from birth might be more beneficial than a flexible one that takes a while to learn, even if it isn’t always perfect.
Journal reference: PNAS, DOI: 10.1073/pnas.2024352118
Sign up for Wild Wild Life, a free monthly newsletter celebrating the diversity science of animals, plants Earth’s other weird wonderful inhabitants
More on these topics:
Source link
Wild horses donkeys dig desert wells that boost biodiversity
A donkey digging a well
E. Lundgren
Feral horses donkeys in the Sonoran desert in North America dig their own wells, inadvertently providing a water source for other animals increasing biodiversity in the area.
Erick Lundgren at Aarhus University in Denmark his colleagues monitored four separate streams in part of the Sonoran desert in Arizona. The streams are usually supplied by groundwater but dry up in the summer. The team surveyed each stream every few weeks over the summers of 2015, 2016 2018, found that horses donkeys in the area dig wells there to access the groundwater.
“It’s a very hot, dry desert you’ll get these pretty magical spots where suddenly there is surface water,” says Lundgren.
The horses donkeys dig wells up to 2 metres in depth to access water. The team saw 59 other vertebrate species at the wells, 57 of which were recorded drinking from the wells. On average, species richness was 51 per cent higher at these wells than observed in nearby dry areas during the same time periods.
“These resources are in fact used by all other animals – there was a cacophony of organisms,” says Lundgren. This included squirrels, mule deer, quails even a black bear at one point, he says.
The wells also function as germination points for plants, especially riparian pioneer trees. These horses donkeys provide a useful source of water for a range of species, which is especially important given that deserts are becoming hotter drier as a result of climate change.
Despite this find, large herbivores are often seen as threats to conservation biodiversity. “Some research from the western United States has shown that feral horses exclude native wildlife from water sources in deserts,” says Lucas Hall at California State University, Bakersfield. “The benefit they may provide by creating new water sources will likely be offset by their high populations exclusionary effects on other wildlife.”
Journal reference: Science, DOI: 10.1126/science.abd6775
Read more on biodiversity
More on these topics:
Source link
Mice on opposite North American coasts evolved the same way
House mice from cold environments (right) have evolved to become bigger than house mice from warm environments (left) in a few hundred years
Katya Mack
On opposite sides of North America, house mice have strikingly similar adaptations to cold climates, have independently evolved changes to genes that drive their similar behaviours hardiness.
House mice (Mus musculus domesticus) are native to Western Europe but have spread across the world thanks to their close association with humans. They arrived in the Americas more than 200 years ago have since expanded into climates quite different from their original temperate home.
To find out how these mice have adapted to new environmental conditions, Michael Nachman at the University of California, Berkeley, his team collected 50 mice from locations in western North America ranging from Arizona in the US north to Alberta, Canada. The team analysed DNA from these wild mice kept some to breed lab populations, comparing the western mice with those from a previous study on mice from eastern North America, ranging from Florida to New York.
The mice were most closely related to those that shared their side of the continent, suggesting that mice in western eastern North America had moved north independently after an initial spreading along a southern route, says Nachman.
Yet the lab-reared mice from Alberta New York were physically similar: both were bigger than southern mice made larger nests, discouraging heat loss providing insulation, respectively.
Nachman was surprised the nest style was so clearly genetically encoded after just a few hundred generations. “Even at room temperature in a comfy lab with plenty of water constant temperature plenty of food, the mice from Canada build a bigger nest than the mice from Arizona,” he says.
The western eastern mice from cold climates shared changes in 16 genes, many involved with the regulation of body temperature.
“This suggests that there’s some predictability to evolution, that some of the same genes have changed in parallel to give rise to similar traits,” says Nachman.
But the mice also showed regional adaptations – such as fur colour changes to hydration regulation genes – which may be due to differences in soil colour rainfall between west east.
It is quite rare to be able to identify possible environmental features that explain divergent genetic changes like those seen in these mice, says Kalina Davies at Queen Mary University of London.
Going forward, Nachman wants to see if the same physical genetic patterns occur in mice spanning the length of South America.
Journal reference: PLOS Genetics, DOI: 10.1371/journal.pgen.1009495
More on these topics:
Source link
Female black widow spider mates with eats multiple males
The mirabilis widow (Latrodectus mirabilis)
Ken Jones/University of Toronto at Scarborough
A South American black widow spider starts biting, wrapping up eating her willing partner before they have finished mating – then mates with (eats) another male.
“Usually there are some advantages to the male for being eaten during mating, like longer copulations as well as decreased female receptivity to future males,” says Luciana Baruffaldi at the University of Toronto, Scarborough, Canada. “In this case, though, we don’t yet know how the male benefits from sexual cannibalism.”
Despite a reputation for eating their mates, …
Source link
Billion-year-old microbe had taken first step towards internal organs
When multicellular organisms grow, their cells can begin differentiating to form internal structures
bennu phoenix/Alamy
A tiny organism that lived a billion years ago had two different cell types, one forming its core another its outer “skin”. It may have been one of the first life forms built that way, making it a crucial step towards modern organisms like animals that also have a skin that is distinct from the cells inside the body.
“This fossil clearly is multicellular with two different types of cell,” says Charles Wellman at the University of …
Source link
1 234 235 236 237 238
|
<urn:uuid:d876f24b-312e-4a6c-b331-5b8a8ccc9351>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.90625,
"fasttext_score": 0.053113579750061035,
"language": "en",
"language_score": 0.9413005709648132,
"url": "https://d3press.us/category/general/page/236/"
}
|
You are here: Home / Journal Articles / Attitudes of Young Adults toward Animals—The Case of High School Students in Belgium and The Netherlands / About
By Pim Martens, Camille Hansart, Bingtao Su
Category Journal Articles
The social context and culture in which individuals grow shapes their perspectives through life. Early on, children learn about animals through storybooks, animated movies, toys, and through interactions with pets and wildlife, and will slowly start to build beliefs around those experiences. Their attitudes towards animals will be influenced by a number of factors, including: sex, age, nationality/ethnicity, residence area, animal-related activities and hobbies, food habits, culture/religion education, and pet ownership. A case study of Dutch and Belgian high school students (aged 12–21) investigated the attitudes of young people towards animals. By using the Animal Attitude Scale (AAS) and the Animal Issue Scale (AIS) questionnaires, our study shows that levels of concern for animal welfare were distinctly higher among: female participants; those who ate little to no meat; Belgian students; pet owners; and those who had been to a zoo at least once. In general, students who reported having more contact with animals also had more positive attitudes towards animals. To understand younger generations and their attitudes toward animals is to understand how future generations will look towards and treat our fellow animals, with which we share the planet Earth.
Marcy Wilhelm-South
Purdue University
Date 2019
Publication Title Animals
Volume 9
Issue 3
Pages 12
Publisher MDPI
DOI 10.3390/ani9030088
Language English
Additional Language English
Cite this work
Researchers should cite this work as follows:
1. Animal welfare
2. Attitudes about animals
3. Belgium
4. High schools
5. Netherlands
6. open access
7. students
8. Young Adult
1. open access
|
<urn:uuid:415bae52-e3c5-4bd4-8dd2-53e6d059c563>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.609375,
"fasttext_score": 0.03436237573623657,
"language": "en",
"language_score": 0.9273004531860352,
"url": "https://habricentral.org/resources/73311"
}
|
3 Steps to Learn and Develop Critical Thinking
Critical thinking is in hot demand, but unfortunately in short supply. Some people are critical thinkers but most people tend to think uncritically.
3 Steps to Learn and Develop Critical Thinking
Eve Ash asks Peter Quarry to explain how critical thinking is learned and developed. Peter explains that recognizing and switching off emotions is the first step. This entails understanding how we feel and considering alternative responses. Also, it’s important not to jump to conclusions. Focus on the facts and seek more evidence before responding. Peter recommends rising above the usual ‘win/lose’ approaches to a problem. Other solutions might emerge if everyone calms down before examining a broader range of possibilities. Be willing to look beyond the ideas and information that merely confirm the view you already have.
Content Summary
Learning Objectives
What is Critical Thinking
Recognize & Switch Off Emotions
Collect & Use Information & Data
Avoid Thinking Errors
Learning Objectives
Peter Quarry discusses critical thinking and how to develop critical thinking skills:
• Be able to define critical thinking
• Develop critical thinking skills
• Recognize and switch off emotions
• Collect and use information and data to make critical decisions
• Learn to avoid thinking errors
A recent study of 4.2 million online job ads, found that the demand for critical thinking skills, has risen by 158%in the last three years.
Look, if you ask a lot of employers, they will tell you that critical thinking is one of the most important skills that they’re looking for in new employees. But they’ll also tell you that it’s one of the hardest skills to find. So it seems to be in hot demand, but kind of short supply.
What is Critical Thinking
Critical Thinking:
• Ability to remove emotion
• Observe facts
• Make logical decisions
Critical thinking is the ability to remove emotion from an issue, to observe the facts about something, and then to use logic to arrive at a decision or conclusion.
Most people naturally think uncritically, and it really wastes a lot of time and energy. So, what are some examples of good critical thinking?
Well, imagine in a marketing department, doing research, collecting evidence and facts, and then basing decisions about the marketing strategy on those facts. Imagine a student at university, in an essay or an assignment, making sure that they use facts and logically use them to arrive at conclusions. Even in a day-to-day situation, critical thinking is about not responding with emotion to what somebody says, but being able to step back, think about the situation logically, and not get offended or upset.
So how do you go about thinking critically?
Thinking Critically:
• Recognize & switch off emotions
• Collect & use information & data
• Avoid thinking errors
First of all, recognize and switch off emotions. Secondly, collect and use information and data. And third, avoid some of the typical thinking errors.
Recognize & Switch Off Emotions
So critical thinking is about removing emotions, focusing on the facts, thinking very rationally. But a lot of people still say, they want to listen to their gut.
There’s no doubt that emotions and gut reactions are important. But there is actually a lot of research that shows that emotions can get in the way of making good decisions. I mean, take anger, for example, it can lead to impulsive behavior. So it can actually get in the way of good critical thinking. Imagine that a customer has posted a really negative review, about some company’s products or services, and imagine a manager reacting angrily and then responding in a really kind of aggressive way that a whole bunch of people then read, and it really kind of gives a bad feeling about what that company’s about.
So, how could the person concerned behave differently so that they switch off their emotions?
They could take some time out and actually ask some questions to try and understand how are they responding to this situation. So, questions like, How am I feeling right now? Why am I feeling this? How is this affecting how I’m responding in this situation? And finally, Is there a better way in which I can handle this?
Switch Off Emotions – Ask Questions:
• How am I feeling right now?
• Why am I feeling this?
• How is this affecting my responses?
• Is there a better way in which I can handle this?
So using the example of the manager who posted the angry reply, what could that person have done differently?
Okay, so they need to start by realizing that they’re angry and defensive. And also understand that the reason for this reaction is because of the one negative post. And also from there kind of understand that the urge was to lash out and to be defensive and to sort of attack this customer back again. And then finally to understand that a much better way of handling that situation is to reach out to the unhappy customer, try and understand what the problem was, and try and solve that. In other words, turn it around into a much more productive and publicly positive situation.
Switch off Emotions:
• Recognize your anger and defensiveness
• Identify the trigger
• Understand your urge to lash out
• Consider a better way to respond
• Resolve & turn it around
So they can ask themselves questions, to understand their own emotions. What else can they do?
Okay so, what they could do is deliberately delay their response.
So something like, they’re feeling angry, just take five.
That’s right, basically, take some time out to let the emotion kind of drain out of the situation that then leaves you in a position where you can think logically about the best way to proceed. Another thing they can do is distance themselves from the situation. So this kind of means pulling yourself back from the situation, from the emotion of the situation, and looking at it from a different perspective. So going back to that manager, what they could do is say, “How does this situation look from the customer’s point of view? What would the customer want or suggest?”
So this is really all about not being driven by your emotions, but instead by logical thinking.
Collect & Use Information & Data
So when thinking critically, you really do have to have the data and the facts at hand.
Let me give you a scenario to try and make this a little bit more real. So, imagine an employee, in a company. There’s a work at home policy. And this particular employee has been found to abuse the policy and the manager finds out and is really mad and reacts by banning any further work at home for everybody in the team. And everybody else has been doing it terrifically, and now they’re all upset and morale has been affected.
So how could this manager have based his or her decision on a logical thinking premise?
First of all, what they should do is avoid premature conclusions and instead get some facts. So before deciding on the situation, the manager could ask him or herself.
“What do I know about this situation? So, I know that one person has abused the work-from-home policy. What don’t I know about the situation? Well, I don’t really know how many other people have abused, if any. So really, I need to find out these bits of information.” And it sounds terribly obvious, but if you found out those facts, you probably wouldn’t have reacted in the same way.
I think a lot of people jump to conclusions.
Absolutely and the whole thing about critical thinking is switching off those emotions, getting the facts, so that you base your decision on them, and chances are, it’s going tobe a much better decision, that’s going to not have a whole lot of ripple effects and create a whole lot of other problems.
Critical Thinking:
• Switching off emotions
• Getting the facts
• Make logical decisions
I guess the manager could really look at the results of the other people who are working at home.
Well, that’s right, he or she needs to do some research. Finding out, how do they feel about the work from home policy? Do they use it very often? Check whether anybody else is abusing it because if nobody else is abusing it and it’s just this one employee, that’s a very different scenario. Really what the manager has to do here is talk on a one-on-one basis with that particular employee, who is abusing the situation.
Well it’s quite therapeutic, isn’t it? Because it gets the person out of the explosion and the stupidity and making an embarrassing mistake.
This is why critical thinking is so important because it’s about switching off that emotion and thinking logically instead.
So if you’ve got a whole lot of data, on any problem, how do you apply that in a logical thinking way?
One of the things you need to do is to try and look for patterns or trends in the information. So going back to our scenario, it may be looking at how everybody in the team uses the work at home policy and realizing that 95% of people use it properly, so you base your conclusion and your strategy on that data. So looking for trends, looking for patterns in the data allow you to kind of extract if you will, the truth or the insight.
Avoid Thinking Errors
We as humans have a lot of ways of thinking, and unfortunately, some of them are a problem. We can make mistakes in the way we think that can lead us into a little bit of a mess.
Can you give me an example?
Okay so, imagine two people are negotiating about something. They’re kind of getting a bit annoyed with one another. And as a result, what’s happening is that both of them are kind of digging their heels in a little bit, “So, I want my position.”You know, “You are arguing for your position.” And as a result, we’re getting stuck into basically what’s called a win/lose situation.
So, what’s the thinking error?
The thinking error here is believing that there are only two ways to solve this issue, your way or my way. And the reality is when we think like this, this either/or thinking, we don’t find out, we don’t discover that “Hey, there’s a whole bunch of possible ways.”There might be another person’s way, there might be A, B, C, who knows? So when we get locked into this either/or thinking, it stops us creatively finding what might be a much better solution to the issue.
So in that situation, what could the two people do?
Well, I think the good thing to do there, would be to kind of separate for a while, just calm down, take five, take ten, just let the emotion settle a little bit and then come back together and try and kind of collaborate. Say to one another, “Okay, we’ve got this problem, there’s your way, there’s my way, but, hey, are there any other possibilities that we haven’t thought of?”And you’ll be amazed, taking the emotion out of it and coming together to think more collaboratively, breaking out of that either/or thinking, can often produce terrific results.
Are there any other common mistakes?
Well, there are a lot. But one that I think’s very important is called confirmation bias, and this is the tendency to only see facts and information that support the view that you already have.
Bit of tunnel vision.
It is indeed. An example of that might be, a doctor who’s seeing a patient. Now, this doctor forms a kind of tentative diagnosis of what he or she thinks is wrong with the patient. But then only asks questions, maybe only orders tests, only look for information, to support the tentative diagnosis and may miss something else entirely.
Thinking Critically: Use facts and logic to solve problems and make decisions
So Peter, do you want to just summarize the essential ingredients of critical thinking?
Sure. Look, it’s about using facts and logic rather than emotion to solve problems and make decisions. And look, the three critical skills are, recognize and switch off your emotions, analyze information and data properly, and use logic to make your decisions.
Thinking Critically:
• Recognize & switch off emotions
• Collect & use information & data
• Use logic to make decisions
|
<urn:uuid:23886c18-9a83-44df-9de6-2c70bde9df76>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.53125,
"fasttext_score": 0.06396710872650146,
"language": "en",
"language_score": 0.9470058083534241,
"url": "https://paminy.com/steps-learn-develop-critical-thinking/"
}
|
Skip to content Skip to sidebar Skip to footer
Widget Atas Posting
Electric Arc Welding: Meaning, Procedure And Equipments Arc Welding
Hi ! Welcome to the a domain all about welder, This a domain was created as a means to provide a variety of education, especially relating to welder movements. this time me will explain circa"Electric Arc Welding: Meaning, Procedure and Equipments" clearly, let's go see in detail...
Electric Arc Welding: Meaning, Procedure and Equipments
After reading this article you will learn about:- 1. Meaning of Electric Arc Welding 2. Procedure of Electric Arc Welding 3. Electric Current for Welding 4. Significance of Polarity 5. Equipments 6. Edge Preparation of a Joint 7. Electrodes.
Meaning of Electric Arc Welding:
The arc welding is a fusion welding process in which the heat required to fuse the metal is obtained from an electric arc between the base metal and an electrode.
The electric arc is produced when two conductors are touches together and then separated by a small gap of 2 to 4 mm, such that the current continues to flow, through the air. The temperature produced by the electric arc is about 4000°C to 6000°C.
A metal electrode is used which supplies the filler metal. The electrode may be flux coated or bare. In case of bare electrode, extra flux material is supplied. Both direct current (D.C.) and alternating current (A.C.) are used for arc welding.
The alternating current for arc is obtained from a step down transformer. The transformer receives current from the main supply at 220 to 440 volts and step down to required voltage i.e., 80 to 100 volts. The direct current for arc is usually obtained from a generator driven by either an electric motor, or patrol or diesel engine.
An open circuit voltage (for striking of arc) in case of D.C. welding is 60 to 80 volts while a closed circuit voltage (for maintaining the arc) is 15 to 25 volts.
Procedure of Electric Arc Welding:
First of all, metal pieces to be weld are thoroughly cleaned to remove the dust, dirt, grease, oil, etc. Then the work piece should be firmly held in suitable fixtures. Insert a suitable electrode in the electrode holder at an angle of 60 to 80° with the work piece.
Select the proper current and polarity. The spot are marked by the arc at the places where welding is to be done. The welding is done by making contact of the electrode with the work and then separating the electrode to a proper distance to produce an arc.
When the arc is obtained, intense heat so produced, melts the work below the arc, and forming a molten metal pool. A small depression is formed in the work and the molten metal is deposited around the edge of this depression. It is called arc crator. The slag is brushed off easily after the joint has cooled. After welding is over, the electrode holder should be taken out quickly to break the arc and the supply of current is switched off.
Electric Current for Welding:
Both D.C. (direct current) and A.C. (alternating current) are used to produce an arc in electric arc welding. Both have their own advantages and applications.
The D.C. welding machine obtains their power from an A.C. motor or diesel/petrol generator or from a solid state rectifier.
The capacities of D.C. machine are:
Up to 600 amperes.
Open Circuit Voltage:
50 to 90 volts, (to produce arc).
Closed Circuit Voltage:
18 to 25 volts, (to maintain arc).
The A.C. welding machine has a step down transformer which receives current from main A.C. supply. This transformer step down the voltage from 220 V-440V to normal open circuit voltage of 80 to 100 volts. The current range available up to 400 amperes in the steps of 50 ampere.
The capacities of A.C. welding machine are:
Electric Arc Welding: Meaning, Procedure and Equipments arc welding
Current Range:
Up to 400 ampere in steps of 50 ampere.
Input Voltage:
220V- 440V
Actual Required Voltage:
80 – 100 volts.
50/60 HZ.
Significance of Polarity:
When D.C. current is used for welding, the following two types of polarity are available:
(i) Straight or positive polarity.
(ii) Reverse or negative polarity.
When the work is made positive and electrode as negative then polarity is called straight or positive polarity, as shown in Fig. 7.16 (a).
In straight polarity, about 67% of heat is distributed at the work (positive terminal) and 33% on the electrode (negative terminal). The straight polarity is used where more heat is required at the work. The ferrous metal such as mild steel, with faster speed and sound weld, uses this polarity.
(a) Straight polarity.
(b) Reverse polarity
On the other hand, when the work is made negative and electrode as positive then polarity is known as reverse or negative polarity, as shown in Fig. 7.16 (b).
In reverse polarity, about 67% of heat is liberated at the electrode (positive terminal) and 33% on the work (negative terminal).
The reverse polarity is used where less heat is required at the work as in case of thin sheet metal weld. The non-ferrous metals such as aluminum, brass, and bronze nickel are welded with reverse polarity.
Equipments Required for Electric Arc Welding:
The various equipments required for electric arc welding are:
1. Welding Machine:
The welding machine used can be A.C. or D.C. welding machine. The A.C. welding machine has a step-down transformer to reduce the input voltage of 220- 440V to 80-100V. The D.C. welding machine consists of an A.C. motor-generator set or diesel/petrol engine-generator set or a transformer-rectifier welding set.
A.C. machine usually works with 50 hertz or 60 hertz power supply. The efficiency of A.C. welding transformer varies from 80% to 85%. The energy consumed per Kg. of deposited metal is 3 to 4 kWh for A.C. welding while 6 to 10 kWh for D.C. welding. A.C. welding machine usually work with low power factor of 0.3 to 0.4, while motor in D.C. welding has a power factor of 0.6 to 0.7. The following table 7.9 shows the voltage and current used for welding machine.
2. Electrode Holders:
Electric Arc Welding: Meaning, Procedure and Equipments arc welding
The function of electrode holder is to hold the electrode at desired angle. These are available in different sizes, according to the ampere rating from 50 to 500 amperes.
3. Cables or Leads:
The function of cables or leads is to carry the current from machine to the work. These are flexible and made of copper or aluminum. The cables are made of 900 to 2000 very fine wires twisted together so as to provide flexibility and greater strength.
4. Cable Connectors and Lugs:
The functions of cable connectors are to make a connection between machine switches and welding electrode holder. Mechanical type connectors are used; as they can he assembled and removed very easily. Connectors are designed according to the current capacity of the cables used.
5. Chipping Hammer:
The function of chipping hammer is to remove the slag after the weld metal has solidified. It has chisel shape and is pointed at one end.
6. Wire Brush, Power Wire Wheel:
The function of wire brush is to remove the slag particles after chipping by chipping hammer. Sometimes, if available a power wire wheel is used in place manual wire brush.
7. Protective Clothing:
The functions of protective clothings used are to protect the hands and clothes of the welder from the heat, spark, ultraviolet and infrared rays. Protective clothing used are leather apron, cap, leather hand gloves, leather sleeves, etc. The high ankle leather shoes must be wear by the welder.
9. Screen or Face Shield:
The function of screen and face shield is to protect the eyes and face of the welder from the harmful ultraviolet and infrared radiations produced during welding. The shielding may be achieved from head helmet or hand helmet.
Edge Preparation of a Joint:
The efficiency and quality of welded joint also depends upon the correct preparation of the edges of the plates to be welded. It is necessary to remove all scales, rust, grease, paint, etc. from the surface before welding.
The cleaning of the surface should be carried out mechanically by wire brush or power wire wheel, and then chemically by carbon tetrachloride. Proper shape to the edges of the plate should be given to produce a proper joint.
The shape of edges may be plain, V-shaped, U-shaped, reshaped, etc. The choice of various edge shapes depends upon the kind, thickness of metal to be welded. Some different types of grooves for edges of the work are shown in Fig. 7.17. BaDD
(i) Square Butt:
It is used when the thickness of the plate is from 3 to 5 mm. Both the edges to be weld should be spaced about 2 to 3mm apart as shown in Fig. 7.17 (a).
(ii) Single- V-Butt:
It is used when the thickness of the plates is from 8 to 16 mm. Both the edges are bevelled to form an angle of about 70° to 90°, as shown if Fig. 7.17 (b).
(Iii) Double-V-Butt:
It is used when the thickness of the plates is more than 16mm and where welding can be performed on both sides of the plate. Both the edges are bevelled to form a double-V, as shown in Fig. 7.17 (c).
(iv) Single and Double-U Butt:
Electric Arc Welding: Meaning, Procedure and Equipments arc welding
It is used when the thickness of the plate is more than 20mm. The edge preparation is difficult but the joints are more satisfactory. It requires less filler metal, as shown in Fig. 7.17 (d) and (e).
Arc Welding Electrodes:
Arc welding electrodes can be classified into two broad categories:
1. Non-Consumable electrodes.
2. Consumable electrodes.
1. Non-Consumable Electrodes:
These electrodes do not consumed during the welding operation, hence they named, non-consumable electrodes. They are generally made of carbon, graphite or tungsten. Carbon electrodes are softer while tungsten and graphite electrodes are hard and brittle.
Carbon and graphite electrodes can be used only for D.C. welding, while tungston electrodes can be used for both D.C. and A.C. welding. The filler material is added separately when these types of electrodes are used. Since, the electrodes do not consumed, the arc obtained is stable.
2. Consumable Electrodes:
These electrodes get melted during welding operation, and supply the filler material. They are generally made with similar composition as the metal to be welded.
The arc length can be maintained by moving the electrode towards or away from the work.
The consumable electrodes may be of following two types:
(i) Bare Electrodes:
These are available in the form of continuous wire or rods. They must be used only with straight polarity in D.C. welding. Bare electrodes do not provide any shielding to the molten metal pool from atmospheric oxygen and nitrogen.
Hence, the welds obtained by these electrodes are of lower strength, lower ductility and lower resistance to corrosion. They find limited use in minor repair and poor quality work. They used to weld wrought iron and mild steel. In modern practice they are not used or rarely used. They are also known as plain electrodes.
(ii) Coated Electrodes:
These are sometimes also called as conventional electrodes. A coating (thin layer) of flux material is applied all-round the welding rod, and hence termed as coated electrode. The flux, during welding, provides a shielding to the molten metal zone from the atmospheric oxygen and nitrogen. This flux also prevents formation of oxides and nitrides. Flux chemically react with the oxides present in the metal and forms a low melting temperature fusible slag.
The slag is float on the top of the weld and can easily be brushed off after solidification of weld. The quality of weld produced by coated electrode is much better as compared to that of bare electrodes.
Depending on the coating factor or thickness of flux coating, coated electrodes are divided in three groups:
(a) Lightly coated electrodes.
(b) Medium coated electrodes.
(c) Heavily coated electrodes.
A comparison of three types of coated electrodes is given in the Table 7.10:
Advantages of Flux Coated Electrodes:
The flux coating on welding electrodes has may advantages. Some of them are following:
Electric Arc Welding: Meaning, Procedure and Equipments arc welding
1. It protects the welding zone from oxidation by providing an atmosphere of inter gas around the arc.
2. It produces low melting temperature slag, which dissolves the impurities present in the metal like oxides and nitrides, and floats on the surface of the weld pool.
3. It refines the grain size of the welded metal.
4. It adds alloying elements to the welded metal.
5. It stabilizes the arc by providing certain chemicals which have this ability.
6. It reduces the spattering of weld metal.
7. It concentrates the arc stream and reduces thermal losses. This result in increased arc temperature.
8. It slows down the cooling rate of weld and accelerates hardening process.
9. It increases the rate of metal deposition and the penetration obtained.
Constituents of Electrode Coatings:
The electrode coating may consists two or more ingredients. Different type of coatings used for different type of metals to be welded.
The constituents of typical electrode coatings and their functions are given in table 7 11. Some of them are discussed here:
1. Slag Forming Constituents:
The slag forming ingredients are silicon oxide (Sio2), Manganese oxide (Mno2), iron oxide (FeO), asbestos, mica, etc. In some cases, aluminum oxide (Al2o3) is also used but it makes the arc less stable.
2. Constituents to Improve Arc Characteristics:
The ingredients to improve arc characteristics are sodium oxides (Na2O), Calcium oxides (CaO), magnesium oxides (MgO), and titanium oxide (TIO2).
3. De-Oxidising Constituents:
The deoxidising ingredients are graphite, powdered aluminum, wood flour, calcium carbonate, starch, cellulose, dolomite, etc.
4. Binding Constituents:
The binding materials used are sodium silicate, potassium silicate and asbestos.
5. Alloying Constituents:
The alloying elements used for improvement of weld strength are vanadium cobalt, molybdenum, aluminum, chromium, nickel, zirconium, tungsten, etc.
Specification of Electrodes:
The specification of electrodes are provided by Bureau of Indian standard IS : 815-1974 (second revision).
Electric Arc Welding: Meaning, Procedure and Equipments arc welding
According to this, the coated electrodes are specified by:
(i) A prefix letter.
(ii) A six digit code number.
(iii) A suffix letter.
(i) Prefix Letter:
The prefix letter indicates the method of manufacturing of electrodes.
These prefix letters with method of manufacturing of electrodes are given in the Table 7.12:
(ii) A Six Digit Code Number:
The six digit code number indicated the performance characteristics and mechanical properties of the weld metal deposit.
The meaning of each individual digit from one to six is given in the Table 7.13:
(iii) Suffix Letter:
The suffix letter indicates the special properties or characteristics of the electrode.
These are given in the Table 7.14:
The first digits of the code number essentially explain the type of covering used on the electrode and this covering signifies the performance characteristics.
There are seven types of covering representing the first digit number are given in the Table 7.15:
The second digit of the code indicates the welding position, as per Table 7.16 given below:
The third digit of the code number indicates welding current conditions recommended by the manufacturer of electrode.
These are given in the Table 7.17:
Electric Arc Welding: Meaning, Procedure and Equipments arc welding
The fourth, fifth and sixth digits of the code number represents tensile strength, maximum yield stress and percentage elongation with impact value.
These are given in the Table 7.18:
In addition to the coding given above, all electrodes must conform to the test requirements of IS: 814 (part I and II) – 1974. Each packet of electrodes must have a marking indicating coding and specification.
IS: 815 coding: E 315 – 411K
Specification: Ref: 814 (Part-1)
The significance of above example is that:
(i) The electrode is manufactured by solid extrusion and is suitable for metal arc welding of mild steel. [E].
(ii) The electrode covering has an appreciable amount of titanium with basic materials and will produce fluid slag. [3].
(iii) The electrode is suitable for welding in the flat, horizontal, vertical and overhead position. [1].
(iv) The electrode is suitable for welding with direct current, with electrode being +ve or -ve. It is also suitable of welding with an alternating current with open circuit voltage less than 90 volts. [5].
(v) The electrode has range of tensile stress of deposited metal is 410 to 510 N/mm2. [411].
(vi) The electrode has a maximum yield stress of deposited metal is 330 N/nm2. [411].
(vii) The electrode has a minimum percentage elongation in tensile test of deposited metal is 20 percent on a gauge length of 5.65 √So and average impact test value of deposited metal is 47J at 27°C. [411].
(viii) The electrode has iron powder in the covering, giving a metal recovery of 130 to 150 percent.
(ix) The electrode conforms to IS: 814 (Part-I)-1974.
Electric Arc Welding: Meaning, Procedure and Equipments
article sourced from
Don't forget to bookmark "Electric Arc Welding: Meaning, Procedure and Equipments" using Ctrl + D or Command + D (Macos). You can share this article using the share button.
Post a Comment for "Electric Arc Welding: Meaning, Procedure And Equipments Arc Welding "
|
<urn:uuid:217549d9-fb13-4261-98f0-a5583a6b7f14>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5625,
"fasttext_score": 0.019540607929229736,
"language": "en",
"language_score": 0.893481969833374,
"url": "https://www.allaboutwelder.com/2020/04/electric-arc-welding-meaning-procedure.html"
}
|
1911 Encyclopædia Britannica/Coleoptera
Coleoptera, a term used in zoological classification for the true beetles which form one of the best-marked and most natural of the orders into which the class Hexapoda (or Insecta) has been divided. For the relationship of the Coleoptera to other orders of insects see Hexapoda. The name (Gr. κολϵός, a sheath, and πτϵρά, wings) was first used by Aristotle, who noticed the firm protective sheaths, serving as coverings for the hind-wings which alone are used for flight, without recognizing their correspondence with the fore-wings of other insects.
These firm fore-wings, or elytra (fig. 1, A), are usually convex above, with straight hind margins (dorsa); when the elytra are closed, the two hind margins come together along the mid-dorsal line of the body, forming a suture. In many beetles the hind-wings are reduced to mere vestiges useless for flight, or are altogether absent, and in such cases the two elytra are often fused together at the suture; thus organs originally intended for flight have been transformed into an armour-like covering for the beetle’s hind-body. In correlation with their heavy build and the frequent loss of the power of flight, many beetles are terrestrial rather than aerial in habit, though a large proportion of the order can fly well.
Aristotle’s term was adopted by Linnaeus (1758), and has been universally used by zoologists. The identification of the elytra of beetles with the fore-wings of other insects has indeed been questioned (1880) by F. Meinert, who endeavoured to compare them with the tegulae of Hymenoptera, but the older view was securely established by the demonstration in pupal elytra by J. G. Needham (1898) and W. L. Tower (1903), of nervures similar to those of the hind-wing, and by the proof that the small membranous structures present beneath the elytra of certain beetles, believed by Meinert to represent the whole of the true fore-wings, are in reality only the alulae.
Structure.—Besides the conspicuous character of the elytra, beetles are distinguished by the adaptation of the jaws for biting, the mandibles (fig. 1, Bb) being powerful, and the first pair of maxillae (fig. 1, Bc) usually typical in form. The maxillae of the second pair (fig. 1, Bd) are very intimately fused together to form what is called the “lower lip” or labium, a firm transverse plate representing the fused basal portions of the maxillae, which may carry a small median “ligula,” representing apparently the fused inner maxillary lobes, a pair of paraglossae (outer maxillary lobes), and a pair of palps. The feelers of beetles differ greatly in the different families (cf. figs. 2b, 9b and 26b, c); the number of segments is usually eleven, but may vary from two to more than twenty.
The head is extended from behind forwards, so that the crown (epicranium) is large, while the face (clypeus) is small. The chin (gula) is a very characteristic sclerite in beetles, absent only in a few families, such as the weevils. There is usually a distinct labrum (fig. 1, Ba).
The prothorax is large and “free,” i.e. readily movable on the mesothorax, an arrangement usual among insects with the power of rapid running. The tergite of the prothorax (pronotum) is prominent in all beetles, reaching back to the bases of the elytra and forming a substantial shield for the front part of the body. The tergal regions of the mesothorax and of the metathorax are hidden under the pronotum and the elytra when the latter are closed, except that the mesothoracic scutellum is often visible—a small triangular or semicircular plate between the bases of the elytra (fig. 1, A). The ventral region of the thoracic skeleton is complex, each segment usually possessing a median sternum with paired episterna (in front) and epimera (behind). The articular surfaces of the haunches (coxae) of the fore-legs are often conical or globular, so that each limb works in a ball-and-socket joint, while the hind haunches are large, displacing the ventral sclerites of the first two abdominal segments (fig. 1, C). The legs themselves (fig. 1, A) are of the usual insectan type, but in many families one, two, or even three of the five foot-segments may be reduced or absent. In beetles of aquatic habit the intermediate and hind legs are modified as swimming-organs (fig. 2, a), while in many beetles that burrow into the earth or climb about on trees the fore-legs are broadened and strengthened for digging, or lengthened and modified for clinging to branches. The hard fore-wings (elytra) are strengthened with marginal ridges, usually inflected ventrally to form epipleura which fit accurately along the edges of the abdomen. The upper surface of the elytron is sharply folded inwards at intervals, so as to give rise to a regular series of external longitudinal furrows (striae) and to form a set of supports between the two chitinous layers forming the elytron. The upper surface often shows a number of impressed dots (punctures). Along the sutural border of the elytron, the chitinous lamella forms a tubular space within which are numerous glands. The glands occur in groups, and lead into common ducts which open in several series along the suture. Sometimes the glands are found beneath the disk of the elytron, opening by pores on the surface. The hind-wings, when developed, are characteristic in form, possessing a sub-costal nervure with which the reduced radial nervure usually becomes associated. There are several curved median and cubital nervures and a single anal, but few cross nervures or areolets. The wing, when not in use, is folded both lengthwise and transversely, and doubled up beneath the elytron; to permit the transverse folding, the longitudinal nervures are interrupted.
EB1911 Coleoptera - Fig. 1.—Structure of Male Stag-Beetle.jpg
Fig. 1.—Structure of Male Stag-Beetle (Lucanus cervus). A, Dorsal view; B, mouth organs; C, under side.
EB1911 Coleoptera - Fig. 2.—Water Beetles.jpg
Fig. 2.—Water Beetles (Dyticidae). a, Beetle; b, head of beetle
with feelers and palps; c, larva; d, pupa.
Ten segments can be recognized—according to the studies of K. W. Verhoeff (1804–1896)—in a beetle’s abdomen, but the tenth sternite is usually absent. On account of the great extension of the metathorax and the haunches of the large hind-legs, the first abdominal sternite is wanting, and the second is usually so much reduced that the foremost apparent ventral sclerite of the abdomen represents the third sternite. From this point backwards the successive abdominal segments, as far as the seventh or eighth, can be readily made out. The ninth and tenth segments are at most times retracted within the eighth. The female can protrude a long flexible tube in connexion with the eighth segment, carrying the sclerites of the ninth at its extremity, and these sclerites may carry short hairy processes—the stylets. This flexible tube is the functional ovipositor, the typical insectan ovipositor with its three pairs of processes (see Hexapoda) being undeveloped among the Coleoptera. In male beetles, however, the two pairs of genital processes (paramera) belonging to the ninth abdominal segment are always present, though sometimes reduced. Between them is situated, sometimes asymmetrically, the prominent intromittent organ.
In the structure of the digestive system, beetles resemble most other mandibulate insects, the food-canal consisting of gullet, crop, gizzard, mid-gut or stomach, intestine and rectum. The stomach is beset throughout its length with numerous small, finger-like caecal tubes. The excretory (malpighian) tubes are few in number, either four or six. Many beetles have, in connexion with the anus, glands which secrete a repellent acid fluid, serving as a defence for the insect when attacked. The “bombardier” ground beetles (fig. 5) have this habit. Oil-beetles (figs. 23 and 24) and ladybirds (fig. 32) defend themselves by ejecting drops of fluid from the knee-joints. The nervous system is remarkably concentrated in some beetles, the abdominal ganglia showing a tendency to become shifted forward and crowded together, and in certain chafers all the thoracic and abdominal ganglia are fused into a single nerve-centre situated in the thorax,—a degree of specialization only matched in the insectan class among the Hemiptera and some muscid flies.
Development.—The embryonic development (see Hexapoda) has been carefully studied in several genera of beetles. As regards growth after hatching, all beetles undergo a “complete” metamorphosis, the wing-rudiments developing beneath the cuticle throughout the larval stages, and a resting pupal stage intervening between the last larval instar[1] and the imago. The coleopterous pupa (figs. 2d, 3c) is always “free,” the legs, wings and other appendages not being fixed to the body as in the pupa of a moth, and the likeness of pupa to perfect insect is very close.
EB1911 Coleoptera - Fig. 3.—Grain Weevils.jpg
From Chittenden, Yearbook, 1894, U.S. Dept. of Agriculture.
Fig. 3.—Grain Weevils. a, Calandra granaria; b, larva; c, pupa;
d, C. oryzae.
The most striking feature in the development of beetles is the great diversity noticeable in the outward form of the larva in different families. The larva of a ground-beetle or a carnivorous water-beetle (fig. 2 c) is an active elongate grub with well-armoured cuticle. The head—carrying feelers, mandibles and two pairs of maxillae—is succeeded by the three thoracic segments, each bearing a pair of strong five-segmented legs, whose feet, like those of the adult, carry two claws. Ten segments can be distinguished in the tapering abdomen, the ninth frequently bearing a pair of tail-feelers (cerci), and the tenth, attached ventrally to the ninth, having the anal opening at its extremity and performing the function of a posterior limb, supporting and temporarily fixing the tail end of the insect on the surface over which it crawls. Such a typically “campodeiform” grub, moving actively about in pursuit of prey, is the one extreme of larval structure to be noticed among the Coleoptera. The other is exemplified by the white, wrinkled, soft-skinned, legless grub of a weevil, which lives underground feeding on roots, or burrows in the tissues of plants (fig. 3 b). Between these two extremes we find various transitional forms: an active larva, as described above, but with four-segmented, single-clawed legs, as among the rove-beetles and their allies; the body well armoured, but slender and worm-like, with very short legs as in wireworms and mealworms (figs. 18, 21 b); the body shortened, with the abdomen swollen, but protected with tubercles and spines, and with longish legs adapted for an active life, as in the predaceous larvae of ladybirds; the body soft-skinned, swollen and caterpillar-like, with legs well developed, but leading a sluggish underground life, as in the grub of a chafer; the body soft-skinned and whitish, and the legs greatly reduced in size, as in the wood-feeding grub of a longhorn beetle. In the case of certain beetles whose larvae do not find themselves amid appropriate food from the moment of hatching, but have to migrate in search of it, an early larval stage, with legs, is followed by later sluggish stages in which legs have disappeared, furnishing examples of what is called hypermetamorphosis. For example, the grub of a pea or bean beetle (Bruchus) is hatched, from the egg laid by its mother on the carpel of a leguminous flower, with three pairs of legs and spiny processes on the prothorax. It bores through and enters the developing seed, where it undergoes a moult and becomes legless. Similarly the newly-hatched larva of an oil-beetle (Meloe) is an active little campodeiform insect, which, hatched from an egg laid among plants, waits to attach itself to a passing bee. Carried to the bee’s nest, it undergoes a moult, and becomes a fat-bodied grub, ready to lead a quiet life feeding on the bee’s rich food-stores.
Distribution and Habits.—The Coleoptera are almost world-wide in their distribution, being represented in the Arctic regions and on almost all oceanic islands. Most of the dominant families—such as the Carabidae (ground-beetles), Scarabaeidae (chafers), or Curculionidae (weevils) have a distribution as wide as the order. But while some large families, such as the Staphylinidae (rove-beetles) are especially abundant on the great northern continents, becoming scarcer in the tropics, others, the Cicindelidae (tiger-beetles), for example, are most strongly represented in the warmer regions of the earth, and become scarce as the collector journeys far to south or north. The distribution of many groups of beetles is restricted in correspondence with their habits; the Cerambycidae (longhorns), whose larvae are wood-borers, are absent from timberless regions, and most abundant in the great tropical forests. Some families are very restricted in their range. The Amphizoidae, for example, a small family of aquatic beetles, are known only from western North America and Eastern Tibet, while an allied family, the Pelobiidae, inhabit the British Isles, the Mediterranean region, Tibet and Australia. The beetles of the British islands afford some very interesting examples of restricted distribution among species. For example, large and conspicuous European beetles, such as the stag-beetle (fig. 1, Lucanus cervus) and the great water-beetle (Hydrophilus piceus, fig. 20), are confined to eastern and southern Britain, and are unknown in Ireland. On the other hand, there are Arctic species like the ground-beetle, Pelophila borealis, and south-western species like the boring weevil, Mesites Tardyi, common in Ireland, and represented in northern or western Britain, but unknown in eastern Britain or in Central Europe. Careful study of insular faunas, such as that of Madeira by T. V. Wollaston, and of the Sandwich Islands by D. Sharp, and the comparison of the species found with those of the nearest continental land, furnish the student of geographical distribution with many valuable and suggestive facts.
Notes on habit are given below in the accounts of the various families. In general it may be stated that beetles live and feed in almost all the diverse ways possible for insects. There are carnivores, herbivores and scavengers among them. Various species among those that are predaceous attack smaller insects, hunt in packs crustaceans larger than themselves, insert their narrow heads into snail-shells to pick out and devour the occupants, or pursue slugs and earthworms underground. The vegetable-feeders attack leaves, herbaceous or woody stems and roots; frequently different parts of a plant are attacked in the two active stages of the life-history; the cockchafers, for example, eating leaves, and their grubs gnawing roots. Some of the scavengers, like the burying beetles, inter the bodies of small vertebrates to supply food for themselves and their larvae, or, like the “sacred” beetle of Egypt, collect for the same purpose stores of dung. Many beetles of different families have become the “unbidden guests” of civilized man, and may be found in dwelling-houses, stores and ships’ cargoes, eating food-stuffs, paper, furniture, tobacco and drugs. Hence we find that beetles of some kind can hold their own anywhere on the earth’s surface. Some climb trees and feed on leaves, while others tunnel between bark and wood. Some fly through the air, others burrow in the earth, while several families have become fully adapted to life in fresh water. A large number of beetles inhabit the deep limestone caves of Europe and North America, while many genera and some whole families are at home nowhere but in ants’ nests. Most remarkable is the presence of a number of beetles along the seashore between tide-marks, where, sheltered in some secure nook, they undergo immersion twice daily, and have their active life confined to the few hours of the low ebb.
Stridulating Organs.—Many beetles make a hissing or chirping sound by rubbing a “scraper,” formed by a sharp edge or prominence on some part of their exoskeleton, over a “file” formed by a number of fine ridges situate on an adjacent region. These stridulating organs were mentioned by C. Darwin as probable examples of the action of sexual selection; they are, however, frequently present in both sexes, and in some families also in the larvae. An account of the principal types of stridulators that have been described has been published by C. J. Gahan (1900). The file may be on the head—either upper or lower surface—and the scraper formed by the front edge of the prothorax, as in various wood-boring beetles (Anobium and Scolytus). Or ridged areas on the sides of the prothorax may be scraped by “files” on the front thighs, as in some ground-beetles. Among the longhorn beetles, the prothorax scrapes over a median file on the mid-dorsal aspect of the mesothorax. In a large number of beetles of different families, stridulating areas occur on various segments of the abdomen, and are scraped by the elytra. It is remarkable that these organs are found in similar positions in genera belonging to widely divergent families, while two genera of the same family may have them in different positions. It follows, therefore, that they have been independently acquired in the course of the evolution of the Coleoptera.
Stridulating organs among beetle-larvae have been noted, especially in the wood-feeding grub of the stag-beetles (Lucanidae) and their allies the Passalidae, and in the dung-eating grubs of the dor-beetles (Geotrupes), which belong to the chafer family (Scarabaeidae). These organs are described by J. C. Schiödte and D. Sharp; in the stag-beetle larva a series of short tubercles on the hind-leg is drawn across the serrate edge of a plate on the haunch of the intermediate legs, while in the Passalid grub the modified tip of the hind-leg acts as a scraper, being so shortened that it is useless for locomotion, but highly specialized for producing sound. Whatever may be the true explanation of stridulating organs in adult beetles, sexual selection can have had nothing to do with the presence of these highly-developed larval structures. It has been suggested that the power of stridulation would be advantageous to wood-boring grubs, the sound warning each of the position of its neighbour, so that adjacent burrowers may not get in each other’s way. The root-feeding larvae of the cockchafer and allied members of the Scarabaeidae have a ridged area on the mandible, which is scraped by teeth on the maxillae, apparently forming a stridulating organ.
Luminous Organs.—The function of the stridulating organs just described is presumably to afford means of recognition by sound. Some beetles emit a bright light from a portion of their bodies, which leads to the recognition of mate or comrade by sight. In the wingless female glow-worm (Lampyris, fig. 15 f) the luminous region is at the hinder end, the organ emitting the light consisting, according to H. von Wielowiejski (1882), of cells similar to those of the fat-body, containing a substance that undergoes oxidation. The illumination is intermittent, and appears to be under the control of the insect’s nervous system. The well-known “fire-flies” of the tropics are large click-beetles (Elateridae), that emit light from paired spots on the prothorax and from the base of the ventral abdominal region. The luminous organs of these beetles consist of a specialized part of the fat-body, with an inner opaque and an outer transparent layer. Its structure has been described by C. Heinemann, and its physiology by R. Dubois (1886), who considers that the luminosity is due to the influence of an enzyme in the cells of the organ upon a special substance in the blood. The eggs and larvae of the fire-flies are luminous as well as the perfect beetles.
Fossil History.—The Coleoptera can be traced back farther in time than any other order of insects with complete transformations, if the structures that have been described from the Carboniferous rocks of Germany are really elytra. In the Triassic rocks of Switzerland remains of weevils (Curculionidae) occur, a family which is considered by many students the most specialized of the order. And when we know that the Chrysomelidae and Buprestidae also lived in Triassic, and the Carabidae, Elateridae, Cerambycidae and Scarabaeidae, in Liassic times, we cannot doubt that the great majority of our existing families had already been differentiated at the beginning of the Mesozoic epoch. Coming to the Tertiary we find the Oligocene beds of Aix, of east Prussia (amber) and of Colorado, and the Miocene of Bavaria, especially rich in remains of beetles, most of which can be referred to existing genera.
Classification.—The Coleoptera have been probably more assiduously studied by systematic naturalists than any other order of insects. The number of described species can now hardly be less than 100,000, but there is little agreement as to the main principles of a natural classification. About eighty-five families are generally recognized; the difficulty that confronts the zoologists is the arrangement of these families in “superfamilies” or “sub-orders.” Such obvious features as the number of segments in the foot and the shape of the feeler were used by the early entomologists for distinguishing the great groups of beetles. The arrangement dependent on the number of tarsal segments—the order being divided into tribes Pentamera, Tetramera, Heteromera and Trimera—was suggested by E. L. Geoffroy in 1762, adopted by P. A. Latreille, and used largely through the 19th century. W. S. Macleay’s classification (1825), which rested principally on the characters of the larvae, is almost forgotten nowadays, but it is certain that in any systematic arrangement which claims to be natural the early stages in the life-history must receive due attention. In recent years classifications in part agreeing with the older schemes but largely original, in accord with researches on the comparative anatomy of the insects, have been put forward. Among the more conservative of these may be mentioned that of D. Sharp (1899), who divides the order into six great series of families: Lamellicornia (including the chafers and stag-beetles and their allies with five-segmented feet and plate-like terminal segments to the feelers); Adephaga (carnivorous, terrestrial and aquatic beetles, all with five foot-segments); Polymorpha (including a heterogeneous assembly of families that cannot be fitted into any of the other groups); Heteromera (beetles with the fore and intermediate feet five-segmented, and the hind-feet four-segmented); Phytophaga (including the leaf-beetles, and longhorns, distinguished by the apparently four-segmented feet), and Rhynchophora (the weevils and their allies, with head prolonged into a snout, and feet with four segments). L. Ganglbauer (1892) divides the whole order into two sub-orders only, the Caraboidea (the Adephaga of Sharp and the older writers) and the Cantharidoidea (including all other beetles), since the larvae of Caraboidea have five-segmented, two-clawed legs, while those of all other beetles have legs with four segments and a single claw. A. Lameere (1900) has suggested three sub-orders, the Cantharidiformia (including the Phytophaga, the Heteromera, the Rhynchophora and most of the Polymorpha of Sharp’s classification), the Staphyliniformia (including the rove-beetles, carrion-beetles and a few allied families of Sharp’s Polymorpha), and the Carabidiformia (Adephaga). Lameere’s classification is founded on the number of abdominal sterna, the nervuration of the wings, the number of malpighian tubules (whether four or six) and other structural characters. Preferable to Lameere’s system, because founded on a wider range of adult characters and taking the larval stages into account, is that of H. J. Kolbe (1901), who recognizes three sub-orders: (i.) the Adephaga; (ii.) the Heterophaga, including the Staphylinoidea, the Actinorhabda (Lamellicornia), the Heterorhabda (most of Sharp’s Polymorpha), and the Anchistopoda (the Phytophaga, with the ladybirds and some allied families which Sharp places among the Polymorpha); (iii.) the Rhynchophora.
Students of the Coleoptera have failed to agree not only on a system of classification, but on the relative specialization of some of the groups which they all recognize as natural. Lameere, for example, considers some of his Cantharidiformia as the most primitive Coleoptera. J. L. Leconte and G. H. Horn placed the Rhynchophora (weevils) in a group distinct from all other beetles, on account of their supposed primitive nature. Kolbe, on the other hand, insists that the weevils are the most modified of all beetles, being highly specialized as regards their adult structure, and developing from legless maggots exceedingly different from the adult; he regards the Adephaga, with their active armoured larvae with two foot-claws, as the most primitive group of beetles, and there can be little doubt that the likeness between larvae and adult may safely be accepted as a primitive character among insects. In the Coleoptera we have to do with an ancient yet dominant order, in which there is hardly a family that does not show specialization in some point of structure or life-history. Hence it is impossible to form a satisfactory linear series.
In the classification adopted in this article, the attempt has been made to combine the best points in old and recent schemes, and to avoid the inconvenience of a large heterogeneous group including the vast majority of the families.
Adephaga.—This tribe includes beetles of carnivorous habit with five segments on every foot, simple thread-like feelers with none of the segments enlarged to form club or pectination, and the outer lobs (galea) of the first maxilla usually two-segmented and palpiform (fig. 4 b). The transverse fold of the hind-wing is towards the tip, about two-thirds of the wing-length from the base. At this fold the median nervure stops and is joined by a cross nervure to the radial, which can be distinguished throughout its length from the subcostal. There are four malpighian tubules. In the ovarian tubes of Adephaga small yolk-chambers alternate with the egg-chambers, while in all other beetles there is only a single large yolk-chamber at the narrow end of the tube. The larvae (fig. 2 c) are active, with well-chitinized cuticle, often with elongate tail-feelers (cerci), and with five-segmented legs, the foot-segment carrying two claws.
EB1911 Coleoptera - Fig. 4.—Mormolyce phyllodes.jpg
Fig. 4.Mormolyce phyllodes. Java. a, Labium; b, maxilla; c, labrum; d, mandible.
The generalized arrangement of the wing-nervure and the nature of the larva, which is less unlike the adult than in other beetles, distinguish this tribe as primitive, although the perfect insects are, in the more dominant families, distinctly specialized. Two very small families of aquatic beetles seem to stand at the base of the series, the Amphizoidae, whose larvae are broad and well armoured with short cerci, and the Pelobiidae, which have elongate larvae, tapering to the tail end, where are long paired cerci and a median process, recalling the grub of a Mayfly.
EB1911 Coleoptera - Fig. 5.—Pheropsophus Jurinei, Fig. 6.—Carabus rutilans.jpg
Fig. 5.Pheropsophus Jurinei. W. Africa. Fig. 6.Carabus rutilans. Spain.
The Dyticidae (fig. 2) are Adephaga highly specialized for life in the water, the hind-legs having the segments short, broad and fringed, so as to be well adapted for swimming, and the feet without claws. The metasternum is without the transverse linear impression that is found in most families of Adephaga. The beetles are ovoid in shape, with smooth contours, and the elytra fit over the edges of the abdomen so as to enclose a supply of air, available for use when the insect remains under water. The fore-legs of many male dyticids have the three proximal foot-segments broad and saucer-shaped, and covered with suckers, by means of which they secure a firm hold of their mates. Larval dyticids (fig. 2 b) possess slender, curved, hollow mandibles, which are perforated at the tip and at the base, being thus adapted for sucking the juices of victims. Large dyticid larvae often attack small fishes and tadpoles. They breathe by piercing the surface film with the tail, where a pair of spiracles are situated. The pupal stage is passed in an earthen cell, just beneath the surface of the ground. Nearly 2000 species of Dyticidae are known: they are universally distributed, but are most abundant in cool countries. The Haliplidae form a small aquatic family allied to the Dyticidae.
EB1911 Coleoptera - Fig. 7.—Cicindela sylvatica, Fig. 8.—Manticora tuberculata.jpg
Fig. 7.Cicindela sylvatica
(Wood Tiger-Beetle). Europe.
Fig. 8.Manticora tuberculata.
S. Africa.
The Carabidae, or ground-beetles, comprising 13,000 species, form the largest and most typical family of the Adephaga (figs. 4, 5, 6), the legs of all three pairs being alike and adapted for rapid running. In many Carabidae the hind-wings are reduced or absent, and the elytra fused together along the suture. Many of our native species spend the day lurking beneath stones, and sally forth at night in pursuit of their prey, which consists of small insects, earthworms and snails. But a number of the more brightly coloured ground-beetles run actively in the sunshine. The carabid larva is an active well-armoured grub with the legs and cerci variable in length. Great differences in the general form of the body may be observed in the family. For example, the stout, heavy body of Carabus (fig. 6) contrasts markedly with the wonderful flattened abdomen and elytra of Mormolyce (fig. 4), a Malayan genus found beneath fallen trees, a situation for which its compressed shape is admirably adapted. Blind Carabidae form a large proportion of cave-dwelling beetles, and several species of great interest live between tide-marks along the seashore.
EB1911 Coleoptera - Fig. 9.jpg
Fig. 9.
The Cicindelidae, or tiger-beetles (figs. 7, 8) are the most highly organized of all the Adephaga. The inner lobe (lacinia) of the first maxilla terminates in an articulated hook, while in the second maxillae (labium) both inner and outer lobes (“ligula” and “para-glossae”) are much reduced. The face (clypeus) is broad, extending on either side in front of the insertion of the feelers. The beetles are elegant insects with long, slender legs, running quickly, and flying in the sunshine. The pronotum and elytra are often adorned with bright colours or metallic lustre, and marked with stripes or spots. The beetles are fierce in nature and predaceous in habit, their sharp toothed mandibles being well adapted for the capture of small insect-victims. The larvae are more specialized than those of other Adephaga, the head and prothorax being very large and broad, the succeeding segments slender and incompletely chitinized. The fifth abdominal segment has a pair of strong dorsal hook-like processes, by means of which the larva supports itself in the burrow which it excavates in the earth, the great head blocking the entrance with the mandibles ready to seize on any unwary insect that may venture within reach.
Two or three families may be regarded as aberrant Adephaga. The Paussidae are a very remarkable family of small beetles, mostly tropical, found only in ants’ nests, or flying by night, and apparently migrating from one nest to another. The number of antennal segments varies from eleven to two. It is supposed that these beetles secrete a sweet substance on which the ants feed, but they have been seen to devour the ants’ eggs and grubs. The Gyrinidae, or whirligig beetles (fig. 9), are a curious aquatic family with the feelers (fig. 9, b) short and reduced as in most Paussidae. They are flattened oval in form, circling with gliding motion over the surface film of the water, and occasionally diving, when they carry down with them a bubble of air. The fore-legs are elongate and adapted for clasping, while the short and flattened intermediate and hind legs form very perfect oar-like propellers. The larva of Gyrinus (fig. 9, c) is slender with elongate legs, and the abdominal segments carry paired tracheal gills.
Staphylinoidea.—The members of this tribe may be easily recognized by their wing-nervuration. Close to a transverse fold near the base of the wing, the median nervure divides into branches which extend to the wing-margin; there is a second transverse fold near the tip of the wing, and cross nervures are altogether wanting. There are four malpighian tubes, and all five tarsal segments are usually recognizable. With very few exceptions, the larva in this group is active and campodeiform, with cerci and elongate legs as in the Adephaga, but the leg has only four segments and one claw.
EB1911 Coleoptera - Fig. 10.—Silpha quadripunctata, Fig. 11.—Necrophorus vespillo.jpg
Fig. 10.Silpha quadripunctata.
Fig. 11.Necrophorus vespillo
(Sexton Beetle). Europe.
The Silphidae, or carrion beetles, form one of the best-known families of this group. They are rotund or elongate insects with conical front haunches, the elytra generally covering (fig. 10) the whole dorsal region of the abdomen, but sometimes leaving as many as four terga exposed (fig. 11). Some of these beetles are brightly coloured, while others are dull black. They are usually found in carrion, and the species of Necrophorus (fig. 11) and Necrophaga are valuable scavengers from their habit of burying small vertebrate carcases which may serve as food for their larvae. At this work a number of individuals are associated together. The larvae that live underground have spiny dorsal plates, while those of the Silpha (fig. 10) and other genera that go openly about in search of food resemble wood-lice. About 1000 species of Silphidae are known. Allied to the Silphidae are a number of small and obscure families, for which reference must be made to monographs of the order. Of special interest among these are the Histeridae, compact beetles (fig. 12) with very hard cuticle and somewhat abbreviated elytra, with over 2000 species, most of which live on decaying matter, and the curious little Pselaphidae, with three-segmented tarsi, elongate palpi, and shortened abdomen; the latter are usually found in ants’ nests, where they are tended by the ants, which take a sweet fluid secreted among little tufts of hair on the beetles’ bodies; these beetles, which are carried about by the ants, sometimes devour their larvae. The Trichopterygidae, with their delicate narrow fringed wings, are the smallest of all beetles, while the Platypsyllidae consist of only a single species of curious form found on the beaver.
EB1911 Coleoptera - Fig. 12-14. Hister iv-maculatus; 13. Oxyporus rufus; Stenus biguttatus.jpg
Fig. 12.
Hister iv-maculatus
(Mimic Beetle). Europe.
Fig. 13.
Oxyporus rufus.
Fig. 14.
Stenus biguttatus.
The Staphylinidae, or rove-beetles—a large family of nearly 10,000 species—may be known by their very short elytra, which cover only two of the abdominal segments, leaving the elongate hind-body with seven or eight exposed, firm terga (figs. 13, 14). These segments are very mobile, and as the rove-beetles run along they often curl the abdomen upwards and forwards like the tail of a scorpion. The Staphylinid larvae are typically campodeiform. Beetles and larvae are frequently carnivorous in habit, hunting for small insects under stones, or pursuing the soft-skinned grubs of beetles and flies that bore in woody stems or succulent roots. Many Staphylinidae are constant inmates of ants’ nests.
EB1911 Coleoptera - Fig. 15.—Glow-worm.jpg
Fig. 15.—Glow-worm. Lampyris noctiluca. a, Male;
b, female; c, larva (ventral view). Europe.
Malacodermata.—In this tribe may be included a number of families distinguished by the softness of the cuticle, the presence of seven or eight abdominal sterna and of four malpighian tubes, and the firm, well-armoured larva (fig. 15, c) which is often predaceous in habit. The mesothoracic epimera bound the coxal cavities of the intermediate legs. The Lymexylonidae, a small family of this group, characterized by its slender, undifferentiated feelers and feet, is believed by Lameere to comprise the most primitive of all living beetles, and Sharp lays stress on the undeveloped structure of the tribe generally.
The Lampyridae are a large family, of which the glow-worm (Lampyris) and the “soldier beetles” (Telephorus) are familiar examples. The female “glow-worm” (fig. 15, b), emitting the well-known light (see above), is wingless and like a larva; the luminosity seems to be an attraction to the male, whose eyes are often exceptionally well developed. Some male members of the family have remarkably complex feelers. In many genera of Lampyridae the female can fly as well as the male; among these are the South European “fireflies.”
EB1911 Coleoptera - Fig. 16.—Clerus apiarus, Fig. 17.—Dermestes.jpg
Fig. 16.Clerus apiarus
(Hive Beetle). Europe.
Fig. 17.Dermestes lardarius
(Bacon Beetle).
Trichodermata.—Several families of rather soft-skinned beetles, such as the Melyridae, Cleridae (fig. 16), Corynetidae, Dermestidae (fig. 17), and Dascillidae, are included in this tribe. They may be distinguished from the Malacodermata by the presence of only five or six abdominal sterna, while six malpighian tubes are present in some of the families. The beetles are hairy and their larvae well-armoured and often predaceous. Several species of Dermestidae are commonly found in houses, feeding on cheeses, dried meat, skins and other such substances. The “bacon beetle” (Dermestes lardarius), and its hard hairy larva, are well known. According to Sharp, all Dermestid larvae probably feed on dried animal matters; he mentions one species that can find sufficient food in the horsehair of furniture, and another that eats the dried insect-skins hanging in old cobwebs.
Sternoxia.—This is an important tribe of beetles, including families with four malpighian tubes and only five or six abdominal sterna, while in the thorax there is a backwardly directed process of the prosternum that fits into a mesosternal cavity. The larvae are elongate and worm-like, with short legs but often with hard strong cuticle.
EB1911 Coleoptera - Fig. 18.—Wireworm.jpg
Fig. 18.—A, Wireworm; B, pupa of Click Beetle; C, adult Click
Beetle (Agriotes lineatum).
The Elateridae or click beetles (fig. 18) have the prosternal process just mentioned, capable of movement in and out of the mesosternal cavity, the beetles being thus enabled to leap into the air, hence their popular name of “click-beetles” or “skip-jacks.” The prothorax is convex in front, and is usually drawn out behind into a prominent process on either side, while the elytra are elongate and tapering. Many of the tropical American Elateridae emit light from the spots on the prothorax and an area beneath the base of the abdomen; these are “fireflies” (see above). The larvae of Elateridae are elongate, worm-like grubs, with narrow bodies, very firm cuticle, short legs, and a distinct anal proleg. They are admirably adapted for moving through the soil, where some of them live on decaying organic matter, while others are predaceous. Several of the elaterid larvae, however, gnaw roots and are highly destructive to farm crops. These are the well-known “wire-worms” (q.v.).
EB1911 Coleoptera - Fig. 19.—Catoxantha bicolor.jpg
Fig. 19.Catoxantha bicolor. Java.
The Buprestidae are distinguished from the Elateridae by the immobility of the prosternal process in the mesosternal cavity and by the absence of the lateral processes at the hind corners of the prothorax. Many tropical Buprestidae are of large size (fig. 19), and exhibit magnificent metallic colours; their elytra are used as ornaments in human dress. The larvae are remarkable for their small head, very broad thorax, with reduced legs, and narrow elongate abdomen. They feed by burrowing in the roots and stems of plants.
Bostrychoidea.—This tribe is distinguished from the Malacoderma and allied groups by the mesothoracic epimera not bounding the coxal cavities of the intermediate legs. The downwardly directed head is covered by the pronotum, and the three terminal antennal segments form a distinct club. To this group belong the Bostrychidae and Ptinidae, well known (especially the latter family) for their ravages in old timber. The larvae are stout and soft-skinned, with short legs in correlation with their burrowing habit. The noises made by some Ptinidae (Anobium) tapping on the walls of their burrows with their mandibles give rise to the “death tick” that has for long alarmed the superstitious.
EB1911 Coleoptera -Fig. 20.—Hydrophilus piceus.jpg
Fig. 20.Hydrophilus piceus
(Black Water Beetle). Europe.
Clavicornia.—This is a somewhat heterogeneous group, most of whose members are characterized by clubbed feelers and simple, unbroadened tarsal segments—usually five on each foot—but in some families and genera the males have less than the normal number on the feet of one pair. There are either four or six malpighian tubes. A large number of families, distinguished from each other by more or less trivial characters, are included here, and there is considerable diversity in the form of the larvae. The best-known family is the Hydrophilidae, in which the feelers are short with less than eleven segments and the maxillary palpi very long. Some members of this family—the large black Hydrophilus piceus (fig. 20), for example—are specialized for an aquatic life, the body being convex and smooth as in the Dyticidae, and the intermediate and hind-legs fringed for swimming. When Hydrophilus dives it carries a supply of air between the elytra and the dorsal surface of the abdomen, while air is also entangled in the pubescence which extends beneath the abdomen on either side, being scooped in bubbles by the terminal segments of the feelers when the insect rises to the surface. Many of the Hydrophilidae construct, for the protection of their eggs, a cocoon formed of a silky material derived from glands opening at the tip of the abdomen. That of Hydrophilus is attached to a floating leaf, and is provided with a hollow, tapering process, which projects above the surface and presumably conveys air to the enclosed eggs. Other Hydrophilidae carry their egg-cocoons about with them beneath the abdomen. Many Hydrophilidae, unmodified for aquatic life, inhabit marshes. The larvae in this family are well-armoured, active and predaceous. Of the numerous other families of the Clavicornia may be mentioned the Cucujidae and Cryptophagidae, small beetles, examples of which may be found feeding on stored seeds or vegetable refuse, and the Mycetophagidae, which devour fungi. The Nitidulidae are a large family with 1600 species, among which members of the genus Meligethes are often found in numbers feeding on blossoms, while others live under the bark of trees and prey on the grubs of boring beetles.
EB1911 Coleoptera - Fig. 21-22 Tenebrio molitor; Blaps mortisaga.jpg
Fig. 21.—(a) Tenebrio molitor
(Flour Beetle). Europe.
(b) Larva, or mealworm.
Fig. 22.Blaps mortisaga
(Churchyard Beetle). Europe.
Heteromera.—This tribe is distinguished by the presence of the normal five segments in the feet of the fore and intermediate legs, while only four segments are visible in the hind-foot. Considerable diversity is to be noticed in details of structure within this group, and for an enumeration of all the various families which have been proposed and their distinguishing characters the reader is referred to one of the monographs mentioned below. Some of the best-known members of the group belong to the Tenebrionidae, a large family containing over 10,000 species and distributed all over the world. The tenebrionid larva is elongate, with well-chitinized cuticle, short legs and two stumpy tail processes, the common mealworm (fig. 21) being a familiar example. Several species of this family are found habitually in stores of flour or grain. The beetles have feelers with eleven segments, whereof the terminal few are thickened so as to form a club. The true “black-beetles” or “churchyard beetles” (Blaps) (fig. 22) belong to this family; like members of several allied genera they are sooty in colour, and somewhat resemble ground beetles (Carabi) in general appearance.
EB1911 Coleoptera - Fig. 23-24 Meloe proscarabaeus, Lytta vesicatoria.jpg
Fig. 23.Meloe proscarabaeus
(Oil Beetle). Europe.
Fig. 24.Lytta vesicatoria
(Blister Beetle). Europe.
The most interesting of the Heteromera, and perhaps of all the Coleoptera, are some beetles which pass through two or more larval forms in the course of the life-history (hypermetamorphosis). These belong to the families Rhipidophoridae and Meloidae. The latter are the oil beetles (fig. 23) or blister beetles (fig. 24), insects with rather soft cuticle, the elytra (often abbreviated) not fitting closely to the sides of the abdomen, the head constricted behind the eyes to form a neck, and the claws of the feet divided to the base. Several of the Meloidae (such as the “Spanish fly,” fig. 24) are of economic importance, as they contain a vesicant substance used for raising medicinal blisters on the human skin. The wonderful transformations of these insects were first investigated by G. Newport in 1851, and have recently been more fully studied by C. V. Riley (1878) and J. H. Fabre. The first larval stage is the “triungulin,” a tiny, active, armoured larva with long legs (each foot with three claws) and cercopods. In the European species of Sitaris and Meloe these little larvae have the instinct of clinging to any hairy object. All that do not happen to attach themselves to a bee of the genus Anthophora perish, but those that succeed in reaching the right host are carried to the nest, and as the bee lays an egg in the cell the triungulin slips off her body on to the egg, which floats on the surface of the honey. After eating the contents of the egg, the larva moults and becomes a fleshy grub with short legs and with paired spiracles close to the dorsal region, so that, as it floats in and devours the honey, it obtains a supply of air. After a resting (pseudo-pupal) stage and another larval stage, the pupa is developed. In the American Epicauta vittata the larva is parasitic on the eggs and egg-cases of a locust. The triungulin searches for the eggs, and, after a moult, becomes changed into a soft-skinned tapering larva. This is followed by a resting (pseudo-pupal) stage, and this by two successive larval stages like the grub of a chafer. The Rhipidophoridae are beetles with, short elytra, the feelers pectinate in the males and serrate in the females. The life-history of Metoecus has been studied by T. A. Chapman, who finds that the eggs are laid in old wood, and that the triungulin seeks to attach itself to a social wasp, who carries it to her nest. There it feeds first as an internal parasite of the wasp-grub, then bores its way out, moults and devours the wasp larva from outside. The wasps are said to leave the larval or pupal Metoecus unmolested, but they are hostile to the developed beetles, which hasten to leave the nest as soon as possible.
Strepsiptera.—Much difference of opinion has prevailed with regard to the curious, tiny, parasitic insects included in this division, some authorities considering that they should be referred to a distinct order, while others would group them in the family Meloidae just described. While from the nature of their life-history there is no doubt that they have a rather close relationship to the Meloidae, their structure is so remarkable that it seems advisable to regard them as at least a distinct tribe of Coleoptera.
They may be comprised in a single family, the Stylopidae. The males are very small, free-flying insects with the prothorax, mesothorax and elytra greatly reduced, the latter appearing as little, twisted strips, while the metathorax is relatively large, with its wings broad and capable of longitudinal folding. The feelers are branched and the jaws vestigial. The female is a segmented, worm-like creature, spending her whole life within the body of the bee, wasp or bug on which she is parasitic. One end of her body protrudes from between two of the abdominal segments of the host; it has been a subject of dispute whether this protruded end is the head or the tail, but there can be little doubt that it is the latter. While thus carried about by the host-insect, the female is fertilized by the free-flying male, and gives birth to a number of tiny triungulin larvae. The chief points in the life-history of Stylops and Xenos, which are parasitic on certain bees (Andrena) and wasps (Polistes), have been investigated by K. T. E. von Siebold (1843) and N. Nassonov (1892). The little triungulins escape on to the body of the bee or wasp; then those that are to survive must leave their host for a non-parasitized insect. Clinging to her hairs they are carried to the nest, where they bore into the body of a bee or wasp larva, and after a moult become soft-skinned legless maggots. The growth of the parasitic larva does not stop the development of the host-larva, and when the latter pupates and assumes the winged form, the stylopid, which has completed its transformation, is carried to the outer world. The presence of a Stylops causes derangement in the body of its host, and can be recognized by various external signs. Other genera of the family are parasitic on Hemiptera—bugs and frog-hoppers—but nothing is known as to the details of their life-history.
Lamellicornia.—This is a very well-marked tribe of beetles, characterized by the peculiar elongation and flattening of three or more of the terminal antennal segments, so that the feeler seems to end in a number of leaf-like plates, or small comb-teeth (fig. 26, b, c). The wings are well developed for flight, and there is a tendency in the group, especially among the males, towards an excessive development of the mandibles or the presence of enormous, horn-like processes on the head or pronotum. There are four malpighian tubes. The larvae are furnished with large heads, powerful mandibles and well-developed legs, but the body-segments are feebly chitinized, and the tail-end is swollen. They feed in wood or spend an underground life devouring roots or animal excrement.
The Lucanidae or stag beetles (figs. 1 and 25) have the terminal antennal segments pectinate, and so arranged that the comb-like part of the feeler cannot be curled up, while the elytra completely cover the abdomen. There are about 600 species in the family, the males being usually larger than the females, and remarkable for the size of their mandibles. In the same species, however, great variation occurs in the development of the mandibles, and the breadth of the head varies correspondingly, the smallest type of male being but little different in appearance from the female. The larvae of Lucanidae live within the wood of trees, and may take three or four years to attain their full growth. The Passalidae are a tropical family of beetles generally considered to be intermediate between stag-beetles and chafers, the enlarged segments of the feeler being capable of close approximation.
EB1911 Coleoptera - Fig. 25.—Cladognathus cinnamomeus, Fig 26.—Melolontha fullo.jpg
Fig. 25.Cladognathus cinnamomeus.
Fig. 26.Melolontha fullo (Cockchafer).
S. Europe, b, Antenna of male;
c, antenna of female.
The Scarabaeidae or chafers are an enormous family of about 15,000 species. The plate-like segments of the feeler (fig. 26, b, c) can be brought close together so as to form a club-like termination; usually the hinder abdominal segments are not covered by the elytra. In this family there is often a marked divergence between the sexes; the terminal antennal segments are larger in the male than in the female, and the males may carry large spinous processes on the head or prothorax, or both. These structures were believed by C. Darwin to be explicable by sexual selection. The larvae have the three pairs of legs well developed, and the hinder abdominal segments swollen. Most of the Scarabaeidae are vegetable-feeders, but one section of the family—represented in temperate countries by the dor-beetles (Geotrupes) (fig. 28) and Aphodius, and in warmer regions by the “sacred” beetles of the Egyptians (Scarabaeus) (fig. 27), and allied genera—feed both in the adult and larval stages, on dung or decaying animal matter. The heavy grubs of Geotrupes, their swollen tail-ends black with the contained food-material, are often dug up in numbers in well-manured fields. The habits of Scarabaeus have been described in detail by J. H. Fabre. The female beetle in spring-time collects dung, which she forms into a ball by continuous rolling, sometimes assisted by a companion. This ball is buried in a suitable place, and serves the insect as a store of food. During summer the insects rest in their underground retreats, then in autumn they reappear to bury another supply of dung, which serves as food for the larvae. Fabre states that the mother-insect carefully arranges the food-supply so that the most nutritious and easily digested portion is nearest the egg, to form the first meal of the young larva. In some species of Copris it is stated that the female lays only two or three eggs at a time, watching the offspring grow to maturity, and then rearing another brood.
EB1911 Coleoptera - Fig. 27.—Scarabaeus Aegyptiorum, Fig. 28.—Geotrupes Blackburnei.jpg
Fig. 27.Scarabaeus
. Africa.
Fig. 28.Geotrupes Blackburnei.
N. America.
EB1911 Coleoptera - Fig. 29.—Phaneus Imperator, Fig. 30.—Cetonia Baxii.jpg
Fig. 29.Phaneus Imperator.
S. America.
Fig. 30.Cetonia Baxii.
W. Africa.
Among the vegetable-feeding chafers we usually find that while the perfect insect devours leaves, the larva lives underground and feeds on roots. Such are the habits of the cockchafer (Melolontha vulgaris) and other species that often cause great injury to farm and garden crops (see Chafer). Many of these insects, such as the species of Phanaeus (fig. 29) and Cetonia (fig. 30), are adorned with metallic or other brilliant colours. The African “goliath-beetles” (fig. 31) and the American “elephant-beetles” (Dynastes) are the largest of all insects.
EB1911 Coleoptera - Fig. 31.—Goliathus giganteus.jpg
Fig. 31.Goliathus giganteus (Goliath Beetle).
Anchistopoda.—The families of beetles included by Kolbe in this group are distinguished by the possession of six malpighian tubes, and a great reduction in one or two of the tarsal segments, so that there seem to be only four or three segments in each foot; hence the names Tetramera and Trimera formerly applied to them. The larvae have soft-skinned bodies sometimes protected by rows of spiny tubercles, the legs being fairly developed in some families and greatly reduced or absent in others. As might be expected, degeneration in larval structure is correlated with a concealed habit of life.
The Coccinellidae, or ladybirds (fig. 32), are a large family of beetles, well known by their rounded convex bodies, usually shining and hairless. They have eleven segments to the feeler, which is clubbed at the tip, and apparently three segments only in each foot. Ladybirds are often brightly marked with spots and dashes, their coloration being commonly regarded as an advertisement of inedibility. The larvae have a somewhat swollen abdomen, which is protected by bristle-bearing tubercles. Like the perfect insects, they are predaceous, feeding on plant-lice (Aphidae) and scale insects (Coccidae). Their role in nature is therefore beneficial to the cultivator. The Endomychidae (fig. 33), an allied family, are mostly fungus-eaters. In the Erotylidae and a few other small related families the feet are evidently four-segmented.
EB1911 Coleoptera - Fig. 32.—Anatio ocellata, Fig. 33.—Endomychus coccineus.jpg
Fig. 32.Anatio ocellata
(Eyed Ladybird). Europe.
Fig. 33.Endomychus coccineus.
EB1911 Coleoptera - Fig. 34.—Sagra cyanea, Fig. 35.—Eumorphus ivguttatus.jpg
Fig. 34.Sagra cyanea.
W. Africa.
Fig. 35.Eumorphus ivguttatus.
EB1911 Coleoptera - Fig. 36.—Lophonocerus barbicornis.jpg
Fig. 36.Lophonocerus barbicornis. S. America.
The Chrysomelidae, or leaf-beetles (figs. 34, 35), are a very large family, with “tetramerous” tarsi; there seem to be only four segments to the foot, but there are really five, the fourth being greatly reduced. The mandibles are strong, adapted for biting the vegetable substances on which these beetles feed, and the palps of the second maxillae have three segments. Most of the Chrysomelidae are metallic in colour and convex in form; in some the head is concealed beneath the prothorax, and the so-called “tortoise” beetles (Cassidinae) have the elytra raised into a prominent median ridge. The most active form of larva found in this family resembles in shape that of a ladybird, tapering towards the tail end, and having the trunk segments protected by small firm sclerites. Such larvae, and also many with soft cuticle and swollen abdomen—those of the notorious “Colorado beetle,” for example—feed openly on foliage. Others, with soft, white, cylindrical bodies, which recall the caterpillars of moths, burrow in the leaves or stems of plants. The larvae of the tortoise-beetles have the curious habit of forming an umbrella-like shield out of their own excrement, held in position by the upturned tail-process. The larvae of the beautiful, elongate, metallic Donaciae live in the roots and stems of aquatic plants, obtaining thence both food and air. The larva pierces the vessels of the plant with sharp processes at the hinder end of its body. In this way it is believed that the sub-aqueous cocoon in which the pupal stage is passed becomes filled with air.
The Cerambycidae, or longhorn beetles, are recognizable by their slender, elongate feelers, which are never clubbed and rarely serrate. The foot has apparently four segments, as in the Chrysomelidae. The beetles are usually elongate and elegant in form, often adorned with bright bands of colour, and some of the tropical species attain a very large size (figs. 36, 37). The feelers are usually longer in the male than in the female, exceeding in some cases by many times the length of the body. The larvae have soft, fleshy bodies, with the head and prothorax large and broad, and the legs very much reduced. They live and feed in the wood of trees. Consequently, beetles of this family are most abundant in forest regions, and reach their highest development in the dense virgin forests of tropical countries, South America being particularly rich in peculiar genera.
EB1911 Coleoptera - Fig. 37.—Phryneta aurocincta.jpg
Fig. 37.Phryneta aurocincta. West Africa.
The Bruchidae, or seed-beetles, agree with the two preceding families in tarsal structure; the head is largely hidden by the pronotum, and the elytra are short enough to leave the end of the abdomen exposed (fig. 38). The development of the pea and bean-beetles has been carefully studied by C. V. Riley, who finds that the young larva, hatched from the egg laid on the pod, has three pairs of legs, and that these are lost after the moult that occurs when the grub has bored its way into the seed. In Great Britain the beetle, after completing its development, winters in the seed, waiting to emerge and lay its eggs on the blossom in the ensuing spring.
EB1911 Coleoptera - Fig. 38.—Bruchus piei, Fig. 39.—Platyrrhinus latirostris.jpg
Fig. 38.Bruchus piei
(Pea Beetle.) Europe.
Fig. 39.Platyrrhinus
latirostris. Europe.
Rhynchophora.—The Rhynchophora are a group of beetles easily recognized by the elongation of the head into a beak or snout, which carries the feelers at its sides and the jaws at its tip. The third tarsal segment is broad and bi-lobed, and the fourth is so small that the feet seem to be only four-segmented. There are six malpighian tubes. The ventral sclerite of the head-skeleton (gula), well developed in most families of beetles, is absent among the Rhynchophora, while the palps of the maxillae are much reduced. The larvae have soft, white bodies and, with very few exceptions, no legs.
EB1911 Coleoptera - Fig. 40-42.—Brenthus anchorago; Otiorrhynchus ligustici; Lixus paraplecticus.jpg
Fig. 40.Brenthus
Tropical Countries.
Fig. 41.Otiorrhyn-
chus ligustici. Europe.
Fig. 42.Lixus paraplecticus.
Of the four families included in this group, the Anthribidae (fig. 39) have jointed, flexible palps, feelers—often of excessive length—with a short basal segment, and the three terminal segments forming a club, and, in some genera, larvae with legs. There are nearly 1000 known species, most of which live in tropical countries. The Brenthidae are a remarkable family almost confined to the tropics; they are elongate and narrow in form (fig. 40), with a straight, cylindrical snout which in some male beetles of the family is longer than the rest of the body.
EB1911 Coleoptera - Fig. 43.—Scolytus ulmi.jpg
Fig. 43.Scolytus ulmi. (Bark Beetle). Europe.
The Curculionidae, or weevils (q.v.), comprising 23,000 species, are by far the largest family of the group. The maxillary palps are short and rigid, and there is no distinct labrum, while the feelers are usually of an “elbowed” form, the basal segment being very elongate (figs. 41, 42). They are vegetable feeders, both in the perfect and larval stages, and are often highly injurious. The female uses her snout as a boring instrument to prepare a suitable place for egg-laying. The larvae (fig. 3) of some weevils live in seeds; others devour roots, while the parent-beetles eat leaves; others, again, are found in wood or under bark. The Scolytidae, or bark-beetles, are a family of some 1500 species, closely allied to the Curculionidae, differing only in the feeble development of the snout. They have clubbed feelers, and their cylindrical bodies (fig. 43) are well adapted for their burrowing habits under the bark of trees. Usually the mother-beetle makes a fairly straight tunnel along which, at short intervals, she lays her eggs. The grubs, when hatched, start galleries nearly at right angles to this, and when fully grown form oval cells in which they pupate; from these the young beetles emerge by making circular holes directly outward through the bark.
Bibliography.—In addition to what may be found in numerous important works on the Hexapoda (q.v.) as a whole, such as J. O. Westwood’s Modern Classification of Insects, vol. i. (London, 1838); J. H. Fabre’s Souvenirs Entomologiques (Paris, 1879–1891); D. Sharp’s contribution to the Cambridge Natural History (vol. vi., London, 1899); and L. C. Miall’s Aquatic Insects (London, 1895), the special literature of the Coleoptera is enormous. Classical anatomical memoirs are those of L. Dufour (Ann. Sci. Nat. ii., iii., iv., vi., viii., xiv., 1824–1828); Ib. (ser. 2, Zool.) i., 1834; and H. E. Strauss-Dürkheim, Anatomie comparée des animaux articulées (Paris, 1828).
The wings of Coleoptera (including the elytra) are described and discussed by F. Meinert (Entom. Tijdsk. v., 1880); C. Hoffbauer (Zeit. f. wissen. Zool. liv., 1892); J. H. Comstock and J. G. Needham (Amer. Nat. xxxii., 1898); and W. L. Tower (Zool. Jahrb. Anat. xvii., 1903). The morphology of the abdomen, ovipositor and genital armature is dealt with by K. W. Verhoeff (Ent. Nachtr. xx., 1894, and Arch. f. Naturg. lxi., lxii., 1895–1896); and B. Wandolleck (Zool. Jahrb. Anat. xxii., 1905).
Luminous organs are described by H. von Wielowiejski (Zeits. f. wissen. Zool. xxxvii., 1882); C. Heinemann (Arch. f. mikr. Anat. xxvii., 1886); and R. Dubois (Bull. soc. zool. France, 1886); and stridulating organs by C. J. Gahan (Trans. Entom. Soc., 1900). See also C. Darwin’s Descent of Man and Selection in Relation to Sex (London, 1871).
Many larvae of Coleoptera are described and beautifully figured by J. C. Schiödte (Naturh. Tidsskr. i.-xiii., 1861–1872). Hypermetamorphosis in the Meloidae is described by G. Newport (Trans. Linn. Soc. xx., xxi., 1851–1853); C. V. Riley (Rep. U.S. Entom. Comm. i., 1878); J. H. Fabre (Ann. Sci. Nat. (4), ix., xix., 1848–1853); H. Beauregard (Les Insectes vésicants, Paris, 1890); and A. Chabaud (Ann. Soc. Ent. France, lx., 1891); in the Bruchidae by Riley (Insect Life, iv., v., 1892–1893); and in the Strepsiptera (Stylopidae) by K. T. E. von Siebold (Arch. f. Naturg. ix., 1843); N. Nassonov (Bull. Univ. Narsovie, 1892); and C. T. Brues (Zool. Jahrb. Anat. xiii., 1903).
For various schemes of classification of the Coleoptera see E. L. Geoffroy (Insectes qui se trouvent aux environs de Paris, Paris, 1762); A. G. Olivier (Coléoptères, Paris, 1789–1808); W. S. MacLeay (Annulosa Javanica, London, 1825); the general works of Westwood and Sharp, mentioned above; M. Gemminger and B. de Harold (Catalogus Coleopterorum, 12 vols., Munich, 1868–1872); T. Lacordaire and F. Chapuis (Genera des Coléoptères, 10 vols., Paris, 1854–1874); J. L. Leconte and G. H. Horn (Classification of Coleoptera of N. America, Washington, Smithsonian Inst., 1883); L. Ganglbauer (Die Käfer von Mitteleuropa, Vienna, 1892, &c.); A. Lameere (Ann. Soc. Ent. Belg. xliv., xlvii., 1900–1903); and H. J. Kolbe (Arch. f. Naturg. lxvii., 1901).
For the British species, W. W. Fowler (Coleoptera of the British Islands, 5 vols., London, 1887–1891) is the standard work; and W. F. Johnson and J. N. Halbert’s “Beetles of Ireland” (Proc. R. Irish Acad., 3, vi., 1902) is valuable faunistically. Among the large number of systematic writers on the order generally, or on special families, may be mentioned D. Sharp, T. V. Wollaston, H. W. Bates, G. C. Champion, E. Reitter, G. C. Crotch, H. S. Gorham, M. Jacoby, L. Fairmaire and C. O. Waterhouse. (G. H. C.)
1. Instar is a convenient term suggested by D. Sharp to indicate a stage in the life-history of an insect between two successive castings of the cuticle.
|
<urn:uuid:30fd59bd-dbc1-49cd-9598-81838da73210>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.953125,
"fasttext_score": 0.020121991634368896,
"language": "en",
"language_score": 0.9318362474441528,
"url": "https://en.m.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica/Coleoptera"
}
|
Why Do We Classify Jobs by Collar Color?
Traditionally, jobs in America are classified by the color of your collar. Common designations include blue, white, or pink collar, and although today they are often metaphoric, they have a lot of traditional concrete significance. The designation of your job today can have wide-ranging effects including judgments of your educational level, socioeconomic status, and gender.
People who are designated as blue-collar workers typically work in a field in which manual labor is required and are typically paid with an hourly wage rather than earning a salary. Traditionally, the job type was seen as a working-class occupation, but today many earn more than workers who have earned a college degree. The term blue-collar began in the 1920s as workers wore darker-colored clothes to avoid showing dirt from their jobs. Many manual laborers also wore denim outfits for their durability and henceforth were known as blue-collar. Some blue-collar workers who worked in particularly dirty industries such as mining or oil working were even downgraded further to black-collar due to the filth of their industries. Historically, blue-collar workers also tended to earn less money and needed durable clothing which would withstand the rigors of their job such as construction, mining, or repair work.
The term white-collar when referring to workers was first created by novelist Upton Sinclair to describe administrative workers who wore a shirt and tie to work. These jobs typically required higher education, a more formal work attire, and were paid a salary rather than on an hourly basis. These positions are generally seen as more “professional”, but in general, these views are outdated and do not reflect today’s realities. As a result of the type of work environments in which he performed they were safer from ruining their clothes and on the off-chance that they did, could more easily afford to have them laundered.
White-collar crime was a term created in 1939 to refer to a variety of frauds carried out within a business setting. These frauds are traditionally seen as less dangerous and are often treated less seriously than “blue-collar” crimes such as murder, assaults, or other violent felonies. Despite society’s value system, crimes are dangerous to society and cause unlimited harm regardless of who carries them out, their degree of violence, and the socioeconomic status of the perpetrator.
While both white and blue-collar took their meaning from the color of the clothing that they wore, pink-collar have a more esoteric origin. Writer Louise Howe created the term in the 1970s to refer to fields where women were highly concentrated at the time such as secretary, nurse, and teacher. These workers were often paid less as they entered the working world in mass and were prohibited from many “male” industries after World War II. This term has often resulted in discrimination towards women and boundaries are beginning to break down as women continue to seek their rightful equality in the workplace.
Other types of collars
As society has changed over the years more types of collar designations have been added. It is now common to refer to someone as a red collar if they work in the government due to the red tape/ink with which they are commonly associated. Red is also commonly known as a symbol of communism so it could also apply to someone who works for the communist party of various nations.
What happens if you are a mix of white and blue-collar? Then a purple collar is for you. This designation refers to people who are commonly assumed to be white-collar workers, but you also perform many blue-collar associated tasks such as an information technology professional.
Other types of collar designations are based both on the clothes that the performer wears and the feelings of society towards their work. For example, prisoners who perform tasks are known as orange-collar, while military workers are known as brown collars for the colors of their uniforms. Green-collar workers have typically been associated with nature and accordingly, green-collar workers tend to work outside. Scarlet-collared workers typically work in sex-based industries and their designation harkens back in culture to Nathaniel Hathorne’s book the Scarlet Letter.
Lastly, we have two types of workers who tend to be derided by the rest of society. First, steel-collar workers is the term used to describe the robots who have taken away blue-collar jobs. Secondly, the term no-collar refers to people who are bohemian and lack a steady job such as artists or craftsmen who value following their passions over making money.
For many years society has judged its citizens first and foremost by their chosen career or profession. A typical first question when you are getting to know someone is what do you do for work as if that sums up a person’s whole personality. We typically make assumptions about a person’s education, intelligence, aptitude, personality, and value simply by the type of job that they do and the collar system allows us to easily sort people into categories from which we can feel justified passing judgment. Just as job categories are increasingly merging and now require a combination of skills and strategies such as purple-collar work, society will benefit from merging all of the colors of collars together and simply evaluating people by who they are and what benefit they bring to others rather than simply by what type of job they perform.
Post a Comment
Previous Post Next Post
|
<urn:uuid:2814442a-6320-4af4-8a14-3e738dc5c4b4>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.5769897699356079,
"language": "en",
"language_score": 0.9852730631828308,
"url": "https://www.jobadvisor.link/2021/06/why-do-we-classify-jobs-by-collar-color.html"
}
|
History of Astronomy From Roman Empire to the Present, part 10
History of Astronomy From Roman Empire to the Present, part 10
Consequently if Mars were on the line O X (in diagram 15), as Dr. Hailey presumed when he invented this method, it would be perpendicular to both A and B, therefore neither one observer or the other would see it at any angle at a 11; as shown in diagram 17.
Of course there will be some ready to contend that Sir David Gill really did measure an angle. That is true; but it will prove to be an actual (physical) deviation of the planet from the perpendicular, which is a very different thing than an angle of parallax.
But it was believed to be a parallactic angle, that is to say— it was supposed to be only an optical or apparent displacement due to the change in the position of the observer from A to B, hence a world of romance is built upon that little angle in this fashion: Angle of Mars 23″ = 35,000,000 miles, 35,000,000×2.6571 =93,000,000= solar parallax 8.80’ = distance of the sun; the sun’s diameter is 875,000 miles; weight X Y Z lbs., age 17,000,000 years, and will probably be burnt out in another 17 million years. 93,000,000 x 2 = 186,000,000 miles diameter of earth’s orbit, the distance to the stars must be billions of miles or even more, they must be a terrific size, and the earth is only like a speck of dust in the Brobdinagian Universe, &c., &c., &c.
But we have not yet done with that angle. Regarded as an angle of parallax, and considered to be equivalent to just such an angle as a surveyor would use in measuring a plot of land, it was of course presumed that the two lines of sight converged so as to meet at a point thirty-five million miles away. (See diagram 18.) This, however, is a mistake, for the two lines of observation, when placed in their proper relations to each other, and in the order as they were taken, should be as in diagram 19, which shows that they diverge.
Now let us study diagram 20, which has been made as simple as possible in order to illustrate the principle involved the more clearly. The letter C is used in this diagram to take the place of G in the earlier diagram 6, because it is simpler to describe the movements of the observer by A, B, C than it is by A, B, G ; easier to convey my meaning.
All the principles and theories of modern astronomy have been carefully observed, and the parallelism of the lines is strictly in accordance with the theories of Greenwich. As I anticipate that in the course of time a battle-royal will wage around this question of the measurement to Mars, I wish to make it quite clear that diagram 20 is designed only to illustrate the principles; it is to clarify the whole proceeding so that the layman can follow the argument. If the Royal Astronomical Society have any objection to make, I will be happy to discuss these questions with them in a manner worthy of the subject. The discussion may then, perhaps, be more refined, indeed.
I foresee a very pretty debate, wherefore I advise them that I know that Sir David did not really take his observations with a twelve hours’ interval as proposed by Dr. Hailey— because it was impossible—but that he actually waited only seven and a half hours (hence my use of C in place of G in diagram 20), but that only elevates the discussion to a higher plane, while the principle and the net results remain the same. In the appointed time and place I will discuss the actual practice if desired, but here I am dealing with the principle; and talking to the layman and the judge.
Now let us get on with this diagram 20. The first observation is taken at A and the second at C. It was evening when the observer was at A, but it is morning when he arrives at C, so that his east and west are reversed, the sun remaining fixed far below the bottom of this page. (The sun is at the observer’s west in the evening, and to his east in the morning, while Mars is in the opposite direction to the sun.)
In this example I have placed the planet exactly on the perpendicular from A to the star of reference, thus “A MARS X.” That is the starting point, or first observation; taken in the evening to the observer’s eastward. Twelve hours later the observer is at C, and sees the same star and the planet both to his west; but Mars is at this time not exactly on the perpendicular, but a little, a very little, to the left of the star.
The planet is not quite as much west as the star, that is to say— being to the left— it is to the eastward in universal geography ; and to the eastward of the perpendicular line C X.
Now if we were not particularly careful, and had not this diagram to guide us, it would be quite natural to think that the first observation (to the east) should be on the left hand, and the other (west) on the right, so as to face each other, so that any angle that might appear, such as an angle of parallax, would be between the two perpendiculars to the star. In that case they would seem to be as shown in diagram 18; but that is wrong!
Referring again to diagram 20, where the observations are illustrated in the proper order as they were actually taken, and all in accordance with the theories of Copernican astronomy, we find that the angle of Mars is to the EASTWARD! outside of the two perpendiculars. This is more simply shown in diagram 19. A being the first observation, on the right, and C, the second observation, on the left; that is correct.
Starting, as we did, with Mars on the perpendicular at A, we know that whenever we shall see it again it must be to the eastward of the star which marks that perpendicular, because, while the star remains fixed in space the planet is moving every hour along its orbit to the eastward round the sun, and so, when we see it from C the next morning, it is as we have shown in diagrams 19 and 20. It has moved from the line A X to a position a little further east in universal space than the line C X.
Whatever displacement there is, is outside the two perpendiculars; so that the second line of sight to Mars diverges from the firs t; consequently no triangulation occurs, and nothing of any material value is accomplished.
The so-called angle of parallax was a displacement due to a real movement of the planet during the night.
In conclusion, as A X and C X are one and the same perpendicular, and no angle, either real or apparent, occurs between them, the first observation A X and the base-line are entirely without value, and may be discarded as useless. (Diagram 21.) This leaves us with only the perpendicular C X and the second observation, which proves to be a narrow inverted triangle “ C X Mars,” where the displacement of the Diagram 21. planet X M— (hitherto known as the parallax of Mars) — indicates how much the planet has moved to the left of the star during the night; while the observer at C is at the apex. Just that, and no more.
About revealed4you
Leave a Reply
WordPress.com Logo
Google photo
Twitter picture
Facebook photo
Connecting to %s
|
<urn:uuid:64567ef2-6ae5-4d29-a6dc-64de8f138b1c>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.890625,
"fasttext_score": 0.0801156759262085,
"language": "en",
"language_score": 0.9552860856056213,
"url": "https://christianflatearthministry.org/2017/08/26/history-of-astronomy-from-roman-empire-to-the-present-part-10/"
}
|
Karst [kahrst] topography is characterized by subterranean limestone caverns, carved by groundwater. It is a landscape shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. Due to subterranean drainage, there may be very limited surface water, even to the absence of all rivers and lakes. Many karst regions display distinctive surface features, with sinkholes or dolines being the most common.
Some karst regions include thousands of caves, even though evidence of caves that are big enough for human exploration is not a required characteristic of karst. Serbian geographer, Jovan Cvijić (1865–1927) is recognized as the father of karst geomorphology. The international community has settled on ‘karst,’ the German name for Kras, a region in Slovenia partially extending into Italy, where it is called ‘Carso’ and where the first scientific research of a karst topography was made. The name has an Indo-European origin (from ‘karra’ meaning ‘stone’).
Leave a Reply
WordPress.com Logo
Google photo
Twitter picture
Facebook photo
Connecting to %s
|
<urn:uuid:0dfbda3d-f40f-4df5-96cc-4ec5cc49068d>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.890625,
"fasttext_score": 0.06086772680282593,
"language": "en",
"language_score": 0.8694031834602356,
"url": "https://thedailyomnivore.net/2011/03/15/karst/"
}
|
Q. 1 B
Choose the correc
Answer :
OPTION A is incorrect because the temperature of the ocean does not increase with depth as there is limited sunlight and no salinity.
OPTION B is correct because the temperature of the ocean decreases with greater depth due to lesser salinity and lack of sunlight.
OPTION C is incorrect as the temperature of the ocean varies according to latitude and salinity, and never remains constant.
OPTION D is incorrect as there is a correct option (Option B)
To Keep in Mind
The temperature drop in the ocean is less gradual near the surface, as salinity and sunlight plays its part. The sunlight keeps the surface water warm, and the salinity reduces the freezing temperature of water.
As the depth increases, effects of both the sunlight and water salinity are substantially minimised, hence pressure and depth make the temperature drop in the lower depths.
It will be useful to understand the concept of Thermocline; it is the zone in the ocean where there is sudden temperature drop in temperature with depth, and effectively separates the surface above from the deep sea below.
Rate this question :
How useful is this solution?
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses
|
<urn:uuid:91b896d0-a56c-46aa-833b-233ff695d25c>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.75,
"fasttext_score": 0.9725283980369568,
"language": "en",
"language_score": 0.908316433429718,
"url": "https://goprep.co/the-temperature-of-the-ocean-waters-generally-at-greater-i-1nlta5"
}
|
Such a Precious Memory, Baby’s First… Poop?!
We can learn a lot from that dirty diaper! A newborn's very first fecal output can provide vital clues about their risk of allergies, asthma and more.
A baby’s first poop is different from all the dirty diapers to follow. It even has a special name — meconium — and it’s thick, tar-like, and dark green. So how might this sticky substance predict allergy risk later in life?
In the womb, babies get nutrition from their pregnant parents via the umbilical cord, and if all goes well they don’t poop until after birth. That protects them from getting feces in their mouths or lungs because they live in a fluid-filled sac. But before birth, they do practice swallowing, and so meconium becomes a time capsule for all the substances they were exposed to in the womb.
Analyzing that first poop provides a rich data set that reflects the environment of the newborn gut, which is rapidly colonized with microbes soon after birth when a baby starts to eat for the first time. Our microbiomes are full of good microbes that are important to health, keeping harmful bacteria from taking up residence and helping us digest food. The richer this initial environment is, the better the odds are of establishing a diverse microbiome in early life, and the lower the odds of developing allergies.
Research led by microbiologist Brett Finlay at the University of British Columbia assessed meconium and stool samples collected from infants within the first two years of life. Based on the molecules present in the samples, the team used machine learning to uncover patterns in the composition of meconium that can predict whether infants go on to develop heightened allergy risk before their first birthday with 76 percent accuracy.
The study was published in Cell Reports Medicine.
The samples and health information of hundreds of infants were obtained through the Canadian Healthy Infant Longitudinal Development (CHILD) study. It follows children as they grow, instead of looking back retrospectively later in life. This is called a prospective study, and it allows researchers to more accurately learn about how early-life exposures lead to health and disease.
Infants with less diversity of metabolites like steroids, amino acids, vitamins and cofactors, and nucleotides in their meconium were more likely go on to develop atopy: a condition where the immune system produces too many IgE antibodies in response to harmless substances that raises their allergy risk. They also found reduced levels of molecules like estriol, which can help people tolerate common allergens.
That same meconium profile also predicts whether the infants would successfully establish keystone microbes in their gut that build a healthy early microbiome.
“This work shows that the development of a healthy immune system and microbiota may actually start well before a child is born — and signals that the tiny molecules an infant is exposed to in the womb play a fundamental role in future health,” said lead author Charisse Petersen in a press release.
Being able to identify newborns at risk of developing atopy could help doctors treat them earlier, and perhaps prevent many related disorders, like eczema (atopic dermatitis), food allergies, asthma, and allergic rhinitis. The process would be totally harmless to the newborn, with the first dirty diaper being the only sample needed.
A healthy early life builds the foundation for a healthy future. The more information that healthcare professionals can access from a baby’s very first day, the better we can support that strong start.
‹ Previous post
Next post ›
|
<urn:uuid:89f97739-5f7a-457d-aa38-47aa2e354563>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.5,
"fasttext_score": 0.021355748176574707,
"language": "en",
"language_score": 0.949334979057312,
"url": "https://research2reality.com/health-medicine/baby-first-poop-allergy-risk-newborns-microbiome-guts/"
}
|
The Normans
The Normans in Britain
by Mandy Barrow
Search our websites
YOU ARE HERE :Homework Index > History > The Normans
WW ll
Roamn Britain
Saxon Britain
Viking Britain
Norman Britain
Tudor Britain
Victorian Britain
World War Two
500 BC
AD 43
An Introduction to the Invaders.
Who were the Normans?
The Normans were people who lived in Normandy in Northern France. They were originally Vikings from Scandinavia. (The name Normandy comes from the French normand, meaning Norsemen and Normans)
(The photographs below and throughout the following page were taken from the Battle of Hastings re-enactment in October 2006)
(After invading Britain they also built castles - to defend their new kingdom)
Norman houses
There were no supermarkets or shops to buy food so the celts ate what food they could grow or hunt.
Vegetables e.g. leeks, onions, turnips, parsnips and carrots.
Wild nuts e.g. hazelnuts and walnuts.
Berries e.g. gooseberries, blackberries and blueberries.
Grains to make bread and also porridge
Herbs e.g. fennel, common sorrel, wild garlic, parsley
Leaves e.g. nettles and spinach
Wild animals e.g. deer, wild boar, fox, beaver, and bear.
Fish e.g. trout, mackerel, and salmon.
Domesticated animals e.g. chicken, goat, sheep and pigs.
Eggs from hens and wild birds eggs.
Honey from bees
Their clothes were made from animals.
They travelled by boat, horseback or on carts pulled by cattle.
The Norman Invasion of England - introduction
The battle of Stamford Bridge
Who was the leader of the Normans?
Who were the Normans? Houses, clothes, food
Where did William fight Harold for the English Throne?
The Battle of Hastings
What happened at the Battle of Hastings?
Who died with an arrow in his eye?
William becomes King - plus Domesday Book info
The Bayeux Tapestry - introduction
What is the Bayeux Tapestry about?
Questions and answers about the Bayeux Tapestry Part one
Questions and answers about the Bayeux Tapestry Part two
Horses | Armour | Shields | Helmets | Weapons
Other websites
email© Copyright - please read
©Copyright Mandy Barrow 2013
Follow me on Twitter @mbarrow
|
<urn:uuid:0d43416c-1ba8-4b9d-9c78-304d5ffd1749>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.609375,
"fasttext_score": 0.13016551733016968,
"language": "en",
"language_score": 0.9059038162231445,
"url": "http://primaryhomeworkhelp.co.uk/bt/who.htm"
}
|
Japanese Verbs Follow Systematic Rules
All Japanese verbs end with “u” when expressed using Roman letters. For example, all of the verbs “yomu (read),” “kaku (write),” “kiku (listen)” and “hanasu (speak)” end with “u.” This is very easy to learn, but we hardly use these “dictionary form” verbs in daily conversation. Many foreigners speak Japanese using the “desu/masu” form, which also conjugates systematically.
As “yomu” conjugates into “yomi masu,” in order to make pronunciation smooth, “u” is replaced with “i.” This occurs in the same manner with other verbs like “kaku,” “kiku,” “hanasu.” There is also another type such as “miru,” “neru” and “taberu” where “ru” is omitted and “masu” is added, i.e: “mi masu,” “ne masu” and “tabe masu.”
“Kuru” and “suru” are exceptions. As for “kuru,” “ru” is omitted and “ku” changes to “ki.” Then “masu” is added, i.e: “ki masu.” As for “suru,” “ru” is omitted and “su” changes to “si” or “shi.” Then “masu” is added, i.e: “si (shi) masu.” Fundamentally, the verbs generally conjugate in the same way using the above-mentioned rule.
It is easy to construct these sentences in the past tense because you just say “mashita” instead of “masu.” As an example, “yomi mashita” is formed from “yomi masu.” In a negative sentence “masu” becomes “masen” and “yomi masu” becomes “yomi masen.” As you see, the “desu/masu” form conjugates systematically. Besides the “desu/masu” form, you just add “ta” to create a sentence in the past tense and “nai” to create a negative sentence. However, “Iku”becomes “itta” instead of “ikuta” and “iku nai” becomes “ika nai” to aid smooth pronunciation. In principle, conjugation also follows a regular pattern.
|
<urn:uuid:8b3d327b-75dd-4e1e-8f34-2aaa3ba9204a>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.984375,
"fasttext_score": 0.9624171257019043,
"language": "en",
"language_score": 0.9311783313751221,
"url": "https://global-skills.jp/hints-for-learning-japanese/japanese-verbs-follow-systematic-rules/"
}
|
Sonoluminescence is the emission of light from imploding bubbles in a liquid when excited by sound.
Single-bubble sonoluminescence – a single, cavitating bubble.
The sonoluminescence effect was first discovered at the University of Cologne in 1934 as a result of work on sonar.[1] Hermann Frenzel and H. Schultes put an ultrasound transducer in a tank of photographic developer fluid. They hoped to speed up the development process. Instead, they noticed tiny dots on the film after developing and realized that the bubbles in the fluid were emitting light with the ultrasound turned on.[2] It was too difficult to analyze the effect in early experiments because of the complex environment of a large number of short-lived bubbles. This phenomenon is now referred to as multi-bubble sonoluminescence (MBSL).
In 1960 Peter Jarman from Imperial College of London proposed the most reliable theory of sonoluminescence phenomenon. He concluded that sonoluminescence is basically thermal in origin and that it might possibly arise from microshocks with the collapsing cavities.[3]
In 1989 an experimental advance was introduced which produced stable single-bubble sonoluminescence (SBSL).[citation needed] In single-bubble sonoluminescence, a single bubble trapped in an acoustic standing wave emits a pulse of light with each compression of the bubble within the standing wave. This technique allowed a more systematic study of the phenomenon, because it isolated the complex effects into one stable, predictable bubble. It was realized that the temperature inside the bubble was hot enough to melt steel, as seen in an experiment done in 2012; the temperature inside the bubble as it collapsed reached about 12,000 kelvins.[4] Interest in sonoluminescence was renewed when an inner temperature of such a bubble well above one million kelvins was postulated.[5] This temperature is thus far not conclusively proven; rather, recent experiments indicate temperatures around 20,000 K (19,700 °C; 35,500 °F).[6]
Some facts about sonoluminescence:[citation needed]
• The light that flashes from the bubbles last between 35 and a few hundred picoseconds long, with peak intensities of the order of 1–10 mW.
Spectral measurements have given bubble temperatures in the range from 2300 K to 5100 K, the exact temperatures depending on experimental conditions including the composition of the liquid and gas.[7] Detection of very high bubble temperatures by spectral methods is limited due to the opacity of liquids to short wavelength light characteristic of very high temperatures.
A study describes a method of determining temperatures based on the formation of plasmas. Using argon bubbles in sulfuric acid, the data shows the presence of ionized molecular oxygen O2+, sulfur monoxide, and atomic argon populating high-energy excited states, which confirms a hypothesis that the bubbles have a hot plasma core.[8] The ionization and excitation energy of dioxygenyl cations, which they observed, is 18 electronvolts. From this they conclude the core temperatures reach at least 20,000 kelvins[6]—hotter than the surface of the sun.
Rayleigh–Plesset equationEdit
The dynamics of the motion of the bubble is characterized to a first approximation by the Rayleigh–Plesset equation (named after Lord Rayleigh and Milton Plesset):
This is an approximate equation that is derived from the Navier–Stokes equations (written in spherical coordinate system) and describes the motion of the radius of the bubble R as a function of time t. Here, μ is the viscosity, p the pressure, and γ the surface tension. The over-dots represent time derivatives. This equation, though approximate, has been shown to give good estimates on the motion of the bubble under the acoustically driven field except during the final stages of collapse. Both simulation and experimental measurement show that during the critical final stages of collapse, the bubble wall velocity exceeds the speed of sound of the gas inside the bubble.[9] Thus a more detailed analysis of the bubble's motion is needed beyond Rayleigh–Plesset to explore the additional energy focusing that an internally formed shock wave might produce.
Mechanism of phenomenonEdit
The mechanism of the phenomenon of sonoluminescence is unknown. Hypotheses include: hotspot, bremsstrahlung radiation, collision-induced radiation and corona discharges, nonclassical light, proton tunneling, electrodynamic jets and fractoluminescent jets (now largely discredited due to contrary experimental evidence).[citation needed]
From left to right: apparition of bubble, slow expansion, quick and sudden contraction, emission of light
In 2002, M. Brenner, S. Hilgenfeldt, and D. Lohse published a 60-page review that contains a detailed explanation of the mechanism.[10] An important factor is that the bubble contains mainly inert noble gas such as argon or xenon (air contains about 1% argon, and the amount dissolved in water is too great; for sonoluminescence to occur, the concentration must be reduced to 20–40% of its equilibrium value) and varying amounts of water vapor. Chemical reactions cause nitrogen and oxygen to be removed from the bubble after about one hundred expansion-collapse cycles. The bubble will then begin to emit light.[11] The light emission of highly compressed noble gas is exploited technologically in the argon flash devices.
Computations based on the theory presented in the review produce radiation parameters (intensity and duration time versus wavelength) that match experimental results[citation needed] with errors no larger than expected due to some simplifications (e.g., assuming a uniform temperature in the entire bubble), so it seems the phenomenon of sonoluminescence is at least roughly explained, although some details of the process remain obscure.
Any discussion of sonoluminescence must include a detailed analysis of metastability. Sonoluminescence in this respect is what is physically termed a bounded phenomenon meaning that the sonoluminescence exists in a bounded region of parameter space for the bubble; a coupled magnetic field being one such parameter. The magnetic aspects of sonoluminescence are very well documented.[12]
Other proposalsEdit
Quantum explanationsEdit
An unusually exotic hypothesis of sonoluminescence, which has received much popular attention, is the Casimir energy hypothesis suggested by noted physicist Julian Schwinger[13] and more thoroughly considered in a paper by Claudia Eberlein[14] of the University of Sussex. Eberlein's paper suggests that the light in sonoluminescence is generated by the vacuum within the bubble in a process similar to Hawking radiation, the radiation generated at the event horizon of black holes. According to this vacuum energy explanation, since quantum theory holds that vacuum contains virtual particles, the rapidly moving interface between water and gas converts virtual photons into real photons. This is related to the Unruh effect or the Casimir effect. The argument has been made that sonoluminescence releases too large an amount of energy and releases the energy on too short a time scale to be consistent with the vacuum energy explanation,[15] although other credible sources argue the vacuum energy explanation might yet prove to be correct.[16]
Nuclear reactionsEdit
Some have argued that the Rayleigh–Plesset equation described above is unreliable for predicting bubble temperatures and that actual temperatures in sonoluminescing systems can be far higher than 20,000 kelvins. Some research claims to have measured temperatures as high as 100,000 kelvins, and speculates temperatures could reach into the millions of kelvins.[17] Temperatures this high could cause thermonuclear fusion. This possibility is sometimes referred to as bubble fusion and is likened to the implosion design used in the fusion component of thermonuclear weapons.
On January 27, 2006, researchers at Rensselaer Polytechnic Institute claimed to have produced fusion in sonoluminescence experiments.[18][19]
Experiments in 2002 and 2005 by R. P. Taleyarkhan using deuterated acetone showed measurements of tritium and neutron output consistent with fusion. However, the papers were considered low quality and there were doubts cast by a report about the author's scientific misconduct. This made the report lose credibility among the scientific community.[20][21][22]
Biological sonoluminescenceEdit
Pistol shrimp (also called snapping shrimp) produce a type of cavitation luminescence from a collapsing bubble caused by quickly snapping its claw. The animal snaps a specialized claw shut to create a cavitation bubble that generates acoustic pressures of up to 80 kPa at a distance of 4 cm from the claw. As it extends out from the claw, the bubble reaches speeds of 60 miles per hour (97 km/h) and releases a sound reaching 218 decibels. The pressure is strong enough to kill small fish. The light produced is of lower intensity than the light produced by typical sonoluminescence and is not visible to the naked eye. The light and heat produced may have no direct significance, as it is the shockwave produced by the rapidly collapsing bubble which these shrimp use to stun or kill prey. However, it is the first known instance of an animal producing light by this effect and was whimsically dubbed "shrimpoluminescence" upon its discovery in 2001.[23] It has subsequently been discovered that another group of crustaceans, the mantis shrimp, contains species whose club-like forelimbs can strike so quickly and with such force as to induce sonoluminescent cavitation bubbles upon impact.[24] A mechanical device with 3D printed snapper claw at five times the actual size was also reported to emit light in a similar fashion,[25] this bioinspired design was based on the snapping shrimp snapper claw molt shed from an Alpheus formosus, the striped snapping shrimp.[26]
See alsoEdit
1. ^ Farley J, Hough S (2003). "Single Bubble Sonoluminsescence". APS Northwest Section Meeting Abstracts: D1.007. Bibcode:2003APS..NWS.D1007F.
2. ^ H. Frenzel and H. Schultes, Luminescenz im ultraschallbeschickten Wasser Zeitschrift für Physikalische Chemie International journal of research in physical chemistry and chemical physics, Published Online: 2017-01-12 | DOI:
3. ^ Jarman, Peter (1960-11-01). "Sonoluminescence: A Discussion". The Journal of the Acoustical Society of America. 32 (11): 1459–1462. Bibcode:1960ASAJ...32.1459J. doi:10.1121/1.1907940. ISSN 0001-4966.
4. ^ Ndiaye AA, Pflieger R, Siboulet B, Molina J, Dufrêche JF, Nikitenko SI (May 2012). "Nonequilibrium vibrational excitation of OH radicals generated during multibubble cavitation in water". The Journal of Physical Chemistry A. 116 (20): 4860–7. Bibcode:2012JPCA..116.4860N. doi:10.1021/jp301989b. PMID 22559729.
5. ^ Moss, William C.; Clarke, Douglas B.; White, John W.; Young, David A. (September 1994). "Hydrodynamic simulations of bubble collapse and picosecond sonoluminescence". Physics of Fluids. 6 (9): 2979–2985. Bibcode:1994PhFl....6.2979M. doi:10.1063/1.868124. ISSN 1070-6631.
6. ^ a b "Temperature inside collapsing bubble four times that of sun | Archives | News Bureau | University of Illinois". 2005-02-03. Retrieved 2012-11-14.
7. ^ Didenko YT, McNamara WB, Suslick KS (January 2000). "Effect of noble gases on sonoluminescence temperatures during multibubble cavitation". Physical Review Letters. 84 (4): 777–80. Bibcode:2000PhRvL..84..777D. doi:10.1103/PhysRevLett.84.777. PMID 11017370.
8. ^ Flannigan DJ, Suslick KS (March 2005). "Plasma formation and temperature measurement during single-bubble cavitation". Nature. 434 (7029): 52–5. Bibcode:2005Natur.434...52F. doi:10.1038/nature03361. PMID 15744295. S2CID 4318225.
9. ^ Barber BP, Putterman SJ (December 1992). "Light scattering measurements of the repetitive supersonic implosion of a sonoluminescing bubble". Physical Review Letters. 69 (26): 3839–3842. Bibcode:1992PhRvL..69.3839B. doi:10.1103/PhysRevLett.69.3839. PMID 10046927.
10. ^ Brenner MP, Hilgenfeldt S, Lohse D (May 2002). "Single-bubble sonoluminescence". Reviews of Modern Physics. 74 (2): 425–484. Bibcode:2002RvMP...74..425B. doi:10.1103/RevModPhys.74.425.
11. ^ Matula TJ, Crum LA (January 1998). "Evidence for gas exchange in single-bubble sonoluminescence". Physical Review Letters. 80 (4): 865–868. Bibcode:1998PhRvL..80..865M. doi:10.1103/PhysRevLett.80.865.
12. ^ Young JB, Schmiedel T, Kang W (December 1996). "Sonoluminescence in high magnetic fields". Physical Review Letters. 77 (23): 4816–4819. Bibcode:1996PhRvL..77.4816Y. doi:10.1103/PhysRevLett.77.4816. PMID 10062638.
13. ^ Schwinger J (1989-03-23). "Cold Fusion: A History of Mine". Retrieved 2012-11-14.
14. ^ Eberlein C (April 1996). "Theory of quantum radiation observed as sonoluminescence" (PDF). Physical Review A. 53 (4): 2772–2787. arXiv:quant-ph/9506024. Bibcode:1996PhRvA..53.2772E. doi:10.1103/PhysRevA.53.2772. PMID 9913192. S2CID 10902274. Archived from the original (PDF) on 2019-03-23.
15. ^ Milton KA (September 2000). "Dimensional and Dynamical Aspects of the Casimir Effect: Understanding the Reality and Significance of Vacuum Energy". p. preprint hep-th/0009173. arXiv:hep-th/0009173.
16. ^ Liberati S, Belgiorno F, Visser M (2000). "Comment on "Dimensional and dynamical aspects of the Casimir effect: understanding the reality and significance of vacuum energy"". p. hep-th/0010140v1. arXiv:hep-th/0010140.
17. ^ Chen W, Huang W, Liang Y, Gao X, Cui W (September 2008). "Time-resolved spectra of single-bubble sonoluminescence in sulfuric acid with a streak camera". Physical Review E. 78 (3 Pt 2): 035301. Bibcode:2008PhRvE..78c5301C. doi:10.1103/PhysRevE.78.035301. PMID 18851095. Lay summaryNature China.
18. ^ "RPI: News & Events – New Sonofusion Experiment Produces Results Without External Neutron Source". 2006-01-27. Retrieved 2012-11-14.
19. ^ "Using Sound Waves To Induce Nuclear Fusion With No External Neutron Source". 2006-01-31. Retrieved 2012-11-14.
21. ^ Jayaraman KS (2008). "Bubble fusion discoverer says his science is vindicated". Nature India. doi:10.1038/nindia.2008.271.
23. ^ Lohse D, Schmitz B, Versluis M (October 2001). "Snapping shrimp make flashing bubbles". Nature. 413 (6855): 477–8. Bibcode:2001Natur.413..477L. doi:10.1038/35097152. PMID 11586346. S2CID 4429684.
24. ^ Patek SN, Caldwell RL (October 2005). "Extreme impact and cavitation forces of a biological hammer: strike forces of the peacock mantis shrimp Odontodactylus scyllarus". The Journal of Experimental Biology. 208 (Pt 19): 3655–64. doi:10.1242/jeb.01831. PMID 16169943.
25. ^ Conover E (15 March 2019). "Some shrimp make plasma with their claws. Now a 3-D printed claw can too". ScienceNews.
26. ^ Tang X, Staack D (March 2019). "Bioinspired mechanical device generates plasma in water via cavitation". Science Advances. 5 (3): eaau7765. Bibcode:2019SciA....5.7765T. doi:10.1126/sciadv.aau7765. PMC 6420313. PMID 30899783.
Further readingEdit
External linksEdit
|
<urn:uuid:4c7a390e-91d0-43f2-9676-e046995dc638>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 4.0625,
"fasttext_score": 0.07137048244476318,
"language": "en",
"language_score": 0.8464303612709045,
"url": "https://en.m.wikipedia.org/wiki/Sonoluminescence"
}
|
Punnett square reflecting a hereditary cross betweslrfc.org 2 heterozygotes (Aa), mirroring a 25% opportunity of offspring having a recessive homozygous condition (aa).
You are watching: What does the notation rr mean to geneticists
The correct answer is A. heterozygous alleles.
Gslrfc.orges are sequslrfc.orgces of DNA that are uncovered on chromosomes. An allele deserve to be characterized as an alternative create of a gslrfc.orge. For instance, a freduced may have purple or white petals. One allele would be for the purple shade and the various other allele for the white shade.
In Mslrfc.orgdelian gslrfc.orgetics, the ethics of prominslrfc.orgce and also recessivslrfc.orgess were uncovered through experimslrfc.orgts that were performed on pea plants. Where traits follow Mslrfc.orgdelian rules they can be either leading or recessive.
A leading allele is a trait that is constantly visible phslrfc.orgocommonly. This means that it is constantly expressed whslrfc.org inherited by progslrfc.orgy. A recessive allele is only sometimes expressed in the phslrfc.orgokind (outside physical appearance of the gslrfc.orgotype).
Chromosomes occur in pairs recognized as homologs. Each member of a homologous pair has the very same gslrfc.orges at the same position on the chromosome. The reason we have actually homologs is that we inherit one from our mommy and one from our father. These 2 alleles might be the exact same or differslrfc.orgt.
One may be dominant and also one recessive, or both dominant or both recessive. If an allele is dominant it is suggested through an uppersituation letter, while if it is recessive, it is shown by a lowersituation letter.
Dominance and also recessivslrfc.orgess
If you inherit an allele that is leading, thslrfc.org you will show the trait regardmuch less of if you only inherit it from your mommy or father. If you inherit a recessive allele thslrfc.org you will certainly only display the trait if you inherit this exact same allele from both of your parslrfc.orgts.
A leading allele basically “dominates” and is constantly checked out. A recessive allele is concealed by the results of a leading allele if you only inherit it from one parslrfc.orgt. This is why recessive traits are oftslrfc.org less common in a populace than leading traits.
The concepts of recessivslrfc.orgess and dominance were uncovered by Gregor Mslrfc.orgdel. Mslrfc.orgdel did experimslrfc.orgts using pea plants, which he bred for a number of gslrfc.orgerations. The gslrfc.orgetics of what was happslrfc.orging was unknown to Mslrfc.orgdel as chromosomes and gslrfc.orges had actually not beslrfc.org discovered yet.
Mslrfc.orgdel, but, realized that tbelow was some trait or factor that was plainly passed from parslrfc.orgtal fees to offspring. He uncovered that occasionally the trait was seslrfc.org in the offspring of parslrfc.orgts, however at other times it was only seslrfc.org in the grandyoungsters of the parslrfc.orgts.
For instance, he discovered that purple flower color was constantly checked out in the following gslrfc.orgeration if also among the parslrfc.orgtal plants had actually purple flowers.
Crossing a plant via white flowers via a plant through purple flowers did not produce equal numbers of white and purple flowers in the offspring. In fact, Mslrfc.orgdel uncovered that only fewer of the young plants would have actually white flowers, compared via purple flowers.
This finding was because the purple, R was a leading allele while the white, r, was a recessive allele. It was the gslrfc.orgokinds of the parslrfc.orgtal fees that affected what traits were inherited and just how they were inherited.
Homozygous and also heterozygous
Alleles that are inherited from parslrfc.orgts can either be the exact same or they can be various. If both alleles are leading or both alleles are recessive thslrfc.org the resulting gslrfc.orgokind is explained as homozygous. If one allele is dominant and also the other allele is recessive, thslrfc.org the gslrfc.orgokind is known as heterozygous.
An example of a heterozygous gslrfc.orgotype thslrfc.org is Rr while a homozygous gslrfc.orgotype could be either RR or rr. If 2 parslrfc.orgts are heterozygotes thslrfc.org tright here is a possibility that ¼ of the offspring have the right to be the homozygote recessive develop.
This is something that Mslrfc.orgdel found. If two pea plants that had actually heterozygous purple flowers were crossed, thslrfc.org ¼ of their progslrfc.orgy would have white flowers.
The various other progslrfc.orgy would have purple flowers. Additionally, ¼ of the offspring would be homozygous purple and also ½ would be heterozygous purple.
A plant which is a heterozygote for purple flowers as soon as crossed with a plant that is homozygous for white flowers would have actually progslrfc.orgy in which ½ were homozygotes for white flowers and also 1/2 were homozygotes for purple flowers.
At the very same time, two pea plants that have actually white flowers will certainly only create offspring with white flowers. This is bereason the white shade is only expressed in the homozygous form givslrfc.org that it is a recessive allele.
Mslrfc.orgdel’s laws
Mslrfc.orgdel uncovered two necessary laws which allow us to predict proparts of gslrfc.orgoforms and phslrfc.orgokinds in the progslrfc.orgy of parslrfc.orgts.
The regulation of segregation says that the alleles sepaprice individually throughout the meiosis that occurs in the germ cells that slrfc.orgd up being the gametes. This indicates that an allele can finish up in any type of of the gametes and also one of the parslrfc.orgt’s alleles will certainly be existing.
The second crucial legislation is the law of indepslrfc.orgdslrfc.orgt assortmslrfc.orgt. This indicates that the alleles are inherited individually of each other. In other words, the selection of one trait is not depslrfc.orgdslrfc.orgt on the selection of one more trait.
The relevance of Mslrfc.orgdelian gslrfc.orgetics
Although many kind of conditions are caused by traits that are inherited in a non-mslrfc.orgdelian fashion, tright here are some illness that do follow Mslrfc.orgdelian rules.
Certain deadly diseases such as Tay-Sachs condition, cystic fibrosis, Huntington’s illness, and also sickle cell anemia are inherited in a Mslrfc.orgdelian means. This indicates that one can predict the likelihood of an illness getting here in the kids based upon the gslrfc.orgotype of the parslrfc.orgtal fees.
Since these illnesses follow rules of dominance and also recessivslrfc.orgess it means that it is feasible, in some situations wbelow the illness is caused by a recessive allele, for parslrfc.orgtal fees to be transferring the allele however not to be sick.
See more: For Each Of These Equations, Determine The Change In The Number Of Moles Of Gas, Δngas.
Cystic fibrosis, Tay-Sachs condition, and sickle cell anemia are all brought about by recessive alleles and also hslrfc.orgce paleas can be asymptomatic carriers. Huntington’s disease, though, is various. This is a disease that is resulted in by a leading allele.
H Chial (2008). What can Gregor Mslrfc.orgdel’s pea plants tell us about huguy disease? Single gslrfc.orge disorders, choose Huntington’s illness and also cystic fibrosis, actually follow Mslrfc.orgdelian inheritance fads. Nature Education.Editors of slrfc.orgcyclopedia Britannica (2018). Mslrfc.orgdelism. Retrieved from slrfc.orgcyclopedia Britannica.RL Dorit, WF Walker, RD Barnes (1991). Zoology. Philadelphia: USA, Saunders College Publishing.RH Ravslrfc.org, RF Evert, SE Eichhorn (1987). Biology of plants, 4th edition. New York: USA, Worth Publishers.C Rye, R Wise, V Jurukovski, J DeSaix, J Choi, Y Avissar (2017). Biology. Houston: USA, Rice College.
|
<urn:uuid:ef1d671e-26a1-4b1e-ae05-54bed305d832>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.19459420442581177,
"language": "en",
"language_score": 0.9327642321586609,
"url": "https://slrfc.org/what-does-the-notation-rr-mean-to-geneticists/"
}
|
-on art, drawing and doodling
Creating a high-quality scientific illustration requires a thorough understanding of biological processes, anatomy, and structural diversity. A major part of learning to identify birds, insects or plants is knowing the key structures to focus on. Comparing limb bones among vertebrates requires an understanding of skeletal anatomy and evolutionary shifts. Biological illustration requires biological knowledge.
But knowledge isn’t enough; if it were, anyone graduating with a biology degree could recreate Audubon’s bird portraits or Leonardo’s anatomical figures. Observation skills are crucial. The abilities to see without bias and to focus on detail and pattern require training, not talent.
%d bloggers like this:
|
<urn:uuid:f1b5088e-2858-4d8c-8e44-daeab43b7a0e>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.546875,
"fasttext_score": 0.6435807347297668,
"language": "en",
"language_score": 0.7537209987640381,
"url": "https://artresponses.com/resources/on-art-drawing-and-doodling/"
}
|
High School Grade Calculations
Within a proficiency-based grading system at our high schools:
1. Teachers and students are able to prioritize skill development instead of point accumulation;
2. Teachers will all use the same formula to calculate end-of-course letter grades;
3. Students will still earn a letter grade on their report cards;
4. Schools still calculate GPAs for transcripts.
5. Each course has a list of standards determined essential for success;
6. Students will receive a score on each standard.
High School Grade Letter Calculation
Grades will not be calculated differently by each teacher through accumulating percentage points for homework, tests, and classwork. Instead, grades will be calculated by all teachers using the following common formula:
A: Met or exceeded all standards. Student earns 4s & 3s on all standards.
B: Met most priority standards. Student earns half or more 4s & 3s on all standards and no 1s on any standards.
C: Met some priority standards and made progress on all standards. Student earns less than half 4s & 3s on all standards and no 1s on any standards.
D: Made progress on all standards. Student earns 2s on all standards.
I or F: Student earns 1 on any standards. I = In Progress, insufficient evidence of learning or of reaching basic standards. With additional time, student may successfully complete the course. F = Not enough evidence of learning. Student needs to repeat the course.
Levels of Proficiency
In the proficiency system:
• Each course has a list of standards determined essential for success;
• Students will receive a score on each standard;
• All teachers will use the following system to score and provide feedback to students on each standard:
• 4: Exceeds the Standard
• 3: Mastery of the Standard
• 2: Approaching the Standard
• 1: Partial Knowledge of the Standard with Assistance
• In High School courses, students who meet or exceed all standards will earn an A; Students who meet or exceed most standards will earn a B.
High School Progress Report Card Example
College and Career Preparation
Colleges and Universities have been awarding credit to high school students based on proficiency for decades through the following avenues:
1. College Board Advanced Placement (AP) Program
2. International Baccalaureate (IB) Program
3. College-Level Examination Program (CLEP)
In these systems, students who can show proficiency by scoring high enough on a test are given college credit. A student who struggled at the beginning of an AP course but improves and scores a 5 on that final exam is given the same college credit as the student who excelled initially and scores a 5. The college only takes into consideration what the student can show they have learned by the end of the course, and disregards the pace a student needed to achieve that learning.
The following are examples of Colleges and Universities that provide proficiency-based degrees, certifications, or courses as part of their offerings for students. Sometimes these systems are called mastery-based, or competency-based.
1. University of Illinois at Urbana-Champaign
2. University of Wisconsin
3. University of Michigan
4. Michigan State University
5. Yale University
6. Northwestern University
7. Penn State
8. Stanford University
9. Duke University
10. John Hopkins University
11. Purdue University
12. University of Kentucky
13. Western Governors University
14. University of Nebraska
15. Vanderbilt University
The following are examples of organizations that offer proficiency-based, competency-based, or mastery-based certifications to train and improve the workforce:
1. Google
2. Goldman Sachs
3. IBM
4. Cisco
5. Association of Certified Professional Accountants
|
<urn:uuid:60f00cac-4a66-4804-91e0-1f42fd762c24>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.921875,
"fasttext_score": 0.14173132181167603,
"language": "en",
"language_score": 0.918445885181427,
"url": "https://pbg.district100.com/grading/high-school-grades"
}
|
Computer Model Explains How Animals Select Actions with Rewarding outcomes
Scientists from the universities of Manchester and Sheffield have developed a computer model charting what happens in the brain when an action is chosen that leads to a reward. The model could provide new insights into the mechanisms behind motor disorders such as Parkinson’s Disease. It may also shed light on conditions involving abnormal learning, such as addiction.
Dr. Mark Humphries from The University of Manchester explains the research: “We wanted to look at how we learn from feedback — particularly how we learn to associate actions to new unexpected outcomes. To do this we created a series of computational models to show how the firing of dopamine neurons caused by receiving reward ultimately translates into selecting the causative action more frequently in the future.” Learning to associate rewarding outcomes with specific actions is a key part of survival, for example searching for food or avoiding predators. It is already known that actions are represented in the cortex — the brain’s outer layer of neural tissue — and rewarding outcomes activate neurons that release a brain chemical called dopamine.
Read the full article here.
|
<urn:uuid:dd56a515-6d2c-431b-96c7-299bd130bdc1>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.71875,
"fasttext_score": 0.034676194190979004,
"language": "en",
"language_score": 0.9388152360916138,
"url": "https://socgen.ucla.edu/2015/01/06/computer-model-explains-how-animals-select-actions-with-rewarding-outcomes/"
}
|
What Are the Functions of Thrust Washers?
Richard Rowe
Thrust washers aren't technically washers; they're bearings that happen to look like washers.
Thrust bearings are far more than just hardware store washers.
A thrust washer is a flat bearing that sandwiches in between a rotating component and a stationary component and acts to keep the rotating component in place by giving it something to brush up against if it starts to move sideways.
Bearing Types
Bearings come in two basic varieties, either flat or rollerized. Flat bearings, like thrust washers and automobile main bearings, work by spreading the load out over a large surface area. This reduces point contact force and, with it, friction. A rollerized bearing uses some sort of mechanical device, such as a ball or needle-like roller, between the flat bearing surfaces to further reduce friction.
Material Lubricity
Thrust washers differ from standard washers in that they're designed at the outset with lubricity in mind. Lubricity refers to how easily one substance slides against another. A pair of bricks will tend to have very poor lubricity because their rough surfaces grip each other. Metals, such as copper, have very high lubricity because they allow other materials to slide easily over them. Thrust washers are generally made of some sort of alloy that offers increased lubricity, which extends bearing life.
Dry Lubricants
Roller bearings tend to outlast thrust washers partially because they offer a bit of space in which to introduce a liquid lubricant. However, purpose-built thrust washers often come from the factory impregnated with a dry lubricant, such as graphite, molybdenum disulfide of boron nitride. Manufacturers add the graphite into the metal during the ingot casting process; as the bearing wears, more graphite particles come to the surface and help to resist wear. Put two graphite-impregnated thrust washers together and you end up with a very slick surface that's highly resistant to wear.
Intermediate Washers
One way to extend the life of a thrust washer assembly is to add one or more intermediate washers. Let's say that the force that a thrust washer must cope with is equal to 100 pounds. If you use a single thrust washer pressing on another thrust washer, each one receives 50 pounds of pressure. Add another washer in between and you have two more wear faces, so each now receives just 25 pounds of pressure. Add another one and you reduce the load to 16.6 pounds of pressure. This translates directly into an improvement in bearing life and possibly friction reduction, depending on the thrust washer type and design.
|
<urn:uuid:445711a8-5c04-43a0-b0ce-60d7c60659e0>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.729834258556366,
"language": "en",
"language_score": 0.9565285444259644,
"url": "https://homesteady.com/12483611/what-are-the-functions-of-thrust-washers"
}
|
The newsletter of the Memory Disorders Project at Rutgers University
What is Epilepsy
Epilepsy is a brain disorder characterized by recurrent seizures, which are uncontrolled, excessive electric discharge by the neurons in the brain.
The prevalence of seizures is very common; about 1 person in 20 will experience at least one seizure during a lifetime. However, the prevalence of epilepsy -- defined by multiple seizures -- is much smaller: about 1 person in 200. Epilepsy does run in families, although it is unlikely that a single gene accounts for the seizures.
One feature of epilepsy is the individual variation; for example, the interval between seizures may vary from minutes to weeks to even years. Many individuals with epilepsy experience an aura or warning of impending seizure (which may take the form of a sensation such as smell, or may simply be a "feeling" that a seizure is about to occur).
Epilepsy Symptoms
In many cases, epileptic seizures arise from a particular site or "focus" in the brain. When there is such a focus, it is often the medial temporal lobe. Repeated severe seizures can damage the underlying brain tissue. Thus, many individuals who suffer severe epilepsy show cognitive deficits, particularly memory deficits due to damage to the medial temporal lobe.
In many cases, epileptic seizures can be controlled or eliminated by the use of drugs, called anti-convulsant drugs or antiepileptic drugs. In cases where drugs are ineffective and seizures are so severe as to be life-threatening, surgery may be conducted to remove the part of the brain where the seizures arise. The surgery is only done on one side of the brain, leaving the other side intact.
The surgery is often very effective, and patients may experience little or no impairments resulting from the lost tissue. (In fact, in some cases, patients appear to show cognitive improvement following surgery - possibly because relief from near-continual seizures allows them to concentrate better.)
Further Reading:
|
<urn:uuid:e67d456c-f1b1-43c1-a5ac-db6c3700581a>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.921875,
"fasttext_score": 0.04935753345489502,
"language": "en",
"language_score": 0.930772066116333,
"url": "https://www.memorylossonline.com/glossary/epilepsy-n118.html"
}
|
Network Redundancy – SY0-601 CompTIA Security+ : 2.5
There are many methods of maintaining the uptime and availability of networks. In this video, you’ll learn about load balancing, NIC teaming, port aggregation, and more.
<< Previous Video: Disk Redundancy Next: Power Redundancy >>
One of the easiest ways to maintain uptime and availability on the network is to include a load balancer as part of the network infrastructure. The load balancer, as its name implies, is going to balance the load between multiple servers so that one person will access the load balancer, and then the load balancer will decide what server is able to provide that particular service. You’ll commonly have multiple servers on a load balancer that are active, which means if anybody is making requests to the load balancer, those servers will be available and provide a response to those requests.
There might also be other servers connected on this load balancer that are up and running and ready to go into action but are currently in a standby mode, and the load balancer will not send any of the traffic to those standby servers. The load balancer is always sending hello messages and checking in with those servers that are active. If any of those active servers suddenly don’t respond back to these health checks, then the load balancer makes a decision to disable the connection to that server and perhaps use a standby server as a replacement.
Here’s an example of a user on the internet that is accessing these servers. When this hits the virtual IP address on this load balancer, the load balancer then determines that server A is available, and it sends the traffic to server A. Most load balancers will also remember which servers were being used by a user, so if this request comes from the same user, the load balancer will remember that this user was using server A, and it will send that traffic to the server A device.
Of course, there may be times when server A becomes unavailable. This might be because of a hardware failure, there might be a power supply that goes out, or the software that’s running on the server suddenly crashes and is no longer able to provide the service. In that case, the load balancer will recognize that that server has failed, and it will put that server into an offline mode. Since this load balancer also has standby servers, it can enable one of those standby servers to be online and available, and any future requests from devices on the internet will use the new server instead of going to the one that’s currently unavailable.
Even if you don’t have a load balancer, you can still provide redundancy to a server using multiple network interface cards on that device. We refer to this as NIC teaming. You might also see this referred to as Load Balancing Fail Over, or LBFO. This allows us to plug in and use these multiple connections to a server, but instead of having a primary connection and a standby connection, we can use both of those connections simultaneously and aggregate the bandwidth between both of them. This provides us with increased throughput, and it also provides us with a way to have redundant paths should one of those connections fail.
On the server, this is usually configured by installing multiple network interface cards on the server, and in the server operating system, those cards are bound together to look as if they are one single interface. We’ll also configure the switch side of this to be able to interpret any of the traffic going to and from those connections as something that’s being NIC teamed in the server. Just as we had a load balancer that sent hello messages to make sure that it would get a response back from those network interfaces, we also have the same functionality within the server. The server is going to have the network interface cards talk to each other, usually over a multicast connection. Those multicast hello messages will go out periodically, and the other interface cards on that server will listen and respond to those hello messages.
If for some reason a network connection becomes unavailable, perhaps a switch has failed or someone accidentally unplugs a cable, that hello message will not get a response from the interface card that’s been disconnected. The server will recognize that that card is no longer talking on the network. It will administratively turn it off and use the other available network interface cards to provide the redundancy and the connectivity for all of the users.
Here’s an example of using this port aggregation where we have a server that has two network interface cards, and both of those network interface cards are going to connect to a switch. We will configure inside the server that will be doing port aggregation across both of those interfaces, and we’ll also configure the switch for port aggregation so that both sides of this connection recognize and understand that this is one single logical connection rather than connecting two physical separate interfaces. This allows multiple users to send traffic through the network and to have a higher bandwidth and throughput between the server and that last switch.
But as you can see from this diagram, there are some places where losing a switch could lose connectivity to the server. For example, there’s a single switch that both of these connections are plugged into, and if that switch fails, then we lose connectivity to the entire server. To provide another level of redundancy, we can configure the connections to go to different switches. We’ll still have the same two network interface cards in the server, but instead of plugging both of those into the same physical switch, we’ll separate them into different switches. That way, if we lose either one of these switches due to a hardware problem or a connectivity issue with the cables, we’ll have a separate path that can be used for all of our users to maintain the connectivity to that server.
|
<urn:uuid:90c257c0-634c-4f2a-aee4-a3dadc3beb33>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.6875,
"fasttext_score": 0.16447818279266357,
"language": "en",
"language_score": 0.9475629925727844,
"url": "https://www.professormesser.com/security-plus/sy0-601/sy0-601-video/network-redundancy/"
}
|
In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus (Figure 2.1) was set up. Which among the following statement(s) is(are) Correct?
Fig 2.1.jpg
(i) Bulb will not glow because electrolyte is not acidic
(ii) Bulb will glow because NaOH is a strong base and furnishes ions for conduction.
(iii) Bulb will not glow because circuit is incomplete
(iv) Bulb will not glow because it depends upon the type of electrolytic solution
(A) (i) and (iii)
(B) (ii) and (iv)
(C) (ii) only
(D) (iv) only
NaOH is an electrolyte . On dissolution in water,
• it will ionize i.e. produce ions.
• Therefore, the solution will conduct electricity and the bulb will glow.
Both acids and bases can act as electrolytes.
So, the correct answer is (c) (ii) only
1. Class 10
About the Author
CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
|
<urn:uuid:81f18c74-4d67-4958-aa58-7bf8627db037>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.90625,
"fasttext_score": 0.8351403474807739,
"language": "en",
"language_score": 0.8357121348381042,
"url": "https://www.teachoo.com/15493/3619/Question-20/category/MCQs-from-NCERT-Exemplar/"
}
|
On This Day…
On the 23rd July 1942 Valdemar Poulsen died
Poulsen was a Danish engineer who made significant contributions to early radio technology. He developed a magnetic wire recorder called the telegraphone in 1898 and the first continuous wave radio transmitter, the Poulsen arc transmitter, in 1903, which was used in some of the first broadcasting stations until the early 1920s.
Magnetic recording was demonstrated in principle as early as 1898 by Poulsen with his telegraphone. Magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetisable medium which moves past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetisation similar to the signal. A playback head (which may be the same as the recording head) can then pick up the changes in the magnetic field from the tape and convert them into an electrical signal.
Poulsen obtained a patent for his invention in 1898 and later developed other magnetic recorders that recorded on steel wire, tape, or disks. None of these devices had electronic amplification, but the recorded signal was easily strong enough to be heard through a headset or even transmitted on telephone wires.
Poulsen arc transmitter
Poulsen developed an arc converter in 1908, referred to as the Poulsen Arc Transmitter, which was widely used in radio before the advent of vacuum tube technology. The system was able to communicate between Lyngby in Denmark and Newcastle with a 100-foot mast.
Roger So Far
The illustrated Corps Centenary book
Buy now: Royal Signals Museum Shop
|
<urn:uuid:630247aa-cfb8-4ba6-bc06-72e25bf8b83f>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.59375,
"fasttext_score": 0.23295217752456665,
"language": "en",
"language_score": 0.969860315322876,
"url": "https://www.royalsignalsmuseum.co.uk/on-this-day-23rd-july/"
}
|
Do you know what a Punnet Square is? Well, if you don't, here's a blog post all about it! Punnet Squares are used to determine the genotype of the offspring of two parents. In my science classroom, we have done a lot of problems with Punnet Squares. They are not that difficult to understand once you get the hang of it. The first step you need to do when you use a Punnet Square is determine both of the parent's genotype. Once you get that, you put one genotype on top of the square, and one genotype on the side of the square. Then you start to cross and get the genotype of the offspring.
One of my science worksheets had to deal with creating Punnet Squares. The problem was given to us and we created a Punnet Square to show our work. For example, one of the problems said, "Bob is homozygous for black hair, and his girlfriend also has black hair but she is heterozygous, what is the chance of them having a baby with black hair?" We would put both of the genotypes on the square and solve for the answer. It would be a 100% chance of have a baby with black hair.
In science class, we learned how to make a DNA ornament for Christmas. There were a lot of steps to the process, but eventually, it became easier as we kept working on it. The ornament wasn't only perfect for a Christmas tree, but it was also able to make earrings, a necklace, or anything else that you would like. Here are the steps we did when we were making the ornament.
The first step we did was picking out the beads and cutting the wire. The phosphates were white and gold, and the paired bases were red, green, blue, and yellow. After that, we started with the first pair. First, we put in the white and gold for the phosphates, then we put one color of the paired bases. We pushed that all the way to the center of the wire. Then we grabbed the wire and inserted that into the other end. We added the phosphate again and other color, but this time it was on the other wire. We kept repeating the process until we had no more beads. Along the way, the wire might get curled up, so you want to avoid that.
After inserting all the beads into the wire, we had a bit of wire left on the ends. With that, we put them through the white beads in the phosphates. Once it got to the end, we pulled it down. We repeated that step to the other side. At the end, it was tied up in a knot from Mrs. Poole which created a little hoop. That is how you make an DNA ornament!
In the past semester, I have learned and studied for a lot in science. We took about 4-5 major tests that were worth many points, and I studied really hard. On all those tests, I got at least an A-. The way I did that was because I studied. It wasn't easy studying, though. There were some topics that I understood very well, and there were some that I had problems with. The one topic I had the most trouble with was studying for DNA. There was a lot to learn about DNA and I couldn't remember all of it in a short period of time.
DNA has a lot of information to it. I studied what its made of, what it does, who discovered it, what it looks like, how it duplicates, etc. It was frustrating for me to know and study all of that because it was long and annoying. But I knew that if I tried harder, it would pay off. So I did. I studied for about 2-3 hours everyday until the test came. And on that test I got a 95%. I think my strategy worked well for me because I achieved my goal, which was to pass that test.
|
<urn:uuid:5c212832-ec35-42c6-8d34-165407db3c01>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.875,
"fasttext_score": 0.07565224170684814,
"language": "en",
"language_score": 0.9885801076889038,
"url": "http://aimeed6if.weebly.com/science-solutions/archives/01-2013"
}
|
Your browser doesn't understand Javascript, you need a more advanced browser.
TOEFL Vocabulary Lesson I
Choose a definition for each of the words below.
1. Abject
A. miserable degraded
B. to think of with joy
C. exact
D. to applaud
2. Acrid
A. without clothing
B. likely; appropriate
C. sharp or bitter taste
D. suitable
3. Dribble
A. to fight as in a contest
B. to flow drop by drop
C. having a small round mark
D. to go bad
4. Dilapidated
A. falling to pieces
B. unfastened
C. to make something bigger
D. folded
5. Emancipate
A. to push down
B. to set free
C. to make known
D. to do better than the others
6. Fastener
A. someone who doesn't eat
B. something that glows
C. something that joins or ties other things together
D. to help with growth
7. Fitting
A. proper, suitable
B. basic
C. filled with fear
D. completely
8. Glow
A. a thing that has worth
B. to send out light without flame
C. serious
D. believable
9. Fund
A. money
B. marked or carved
C. that which can not be touched
D. uplifting
10. Fizz
A. free of disease germs
B. very large
C. strong
D. to make a bubbling hissing sound
Your score is :
Okay now that you know what each word means, use each of these words in a phrase and e-mail me (or your teacher) your completed sentences. This does not mean that you need not use a dictionary to understand the words a little better!
You're being engineers, I suppose I don't have to tell you to copy and paste this list of words onto your e-mail.
|
<urn:uuid:6f2d8f4f-c437-4be2-b471-d4121a235228>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.640625,
"fasttext_score": 0.9983599185943604,
"language": "en",
"language_score": 0.9196383357048035,
"url": "http://www.emse.fr/%7Eyukna/toefl/ToeflI.htm"
}
|
Steve Vollmer, assistant professor of marine and environmental sciences, Marine Science Center
Coral reefs are essential habitats for fish, and understanding what makes them resilient is crucial to their conservation.
One common threat is white-band disease, which has caused massive reef die-offs in the Caribbean. It manifests as a white strip of dead and dying tissue that creeps up the trunk of a living coral. Little was known about what causes the disease—until recently.
In 2011, Vollmer’s team established that the pathogen is likely a type of bacterium, not a virus. Vollmer has since launched a multiyear study looking at hundreds of corals, both healthy and diseased. His team is using next-generation gene sequencing to identify the various bacteria that live on corals, and the team has already homed in on two bacteria types that may be causing the white-band disease specifically.
Vollmer hopes the gene-sequencing work will also help determine why some corals are resistant to the disease, while others succumb.
|
<urn:uuid:4219b0c1-e64d-4dcc-bc0f-c7de92898c1a>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.890625,
"fasttext_score": 0.6716850399971008,
"language": "en",
"language_score": 0.9564443826675415,
"url": "http://www.northeastern.edu/magazine/resilience-for-reefs/"
}
|
What's New
of the
Guest Book
Printer Friendly version of article; but beware, this prints out all 59 pages( Internet Express) or36 pages (Netscape) (0.25 MB for the entire article). If you just want one section printed out, go to the specific class section that you want(see individual class sections listed at the bottom of this page).
The Phylum Mollusca
(an Introduction, for High-school level students, and all others interested!!)
By Avril Bourquin
Science Editing by Ross Mayhew
May, 2000
Glossary and separate page links are in blue and underlined. You may have to use your back button to navigate back to article when in the glossary or in external web sites or pages..
All of the Taxonomy in the Advanced Article is being updated for in regards to structure and picture content. Thank you for your patience
Early Beginnings:
The time is now about 600 million years ago and the first molluscs have made their appearance on our world. About 100 million years later, during the Ordovician period, at least six of the seven classes of molluscs represented today were present. Many of these first molluscs were but simple, worm-like animals, having segments similar to what we find in annelid worms and arthropods. These first molluscs crawled about the primeval seas, probing for and eating microscopic bits of food.
The great landmass of Pangaea slowly deposits dissolved salts and other chemicals into the ocean. The first primitive molluscs in these oceans now digest these chemicals and begin to use the nutrients to build themselves protective shelters (shells) against their hostile environment. As Pangaea breaks apart around 200 million years ago, the world's great continents slowly migrate, due to plate tectonics, and we begin to recognize the world continents as they are today.
Over time, the molluscs flourish and evolve to fit newly developing habitats. Fossil records show some groups ("taxa") growing larger, some smaller. Some grow spiny, others, shiny. Some coil tighter, some looser. Some coil left to right while others loose their coil all together. Some even loose their shells completely. Some, like the ammonids, evolve into huge numbers of species, and then mysteriously disappear forever only to be found as fossils. About 400 Million years ago, some of these molluscs, first the bivalves, begin to inhabit the worlds freshwater streams and lakes. It took at least another 300 million years for certain gastropods to evolve to where they were capable of populating all land and freshwater water habitats.
During the last million years, the land and freshwater molluscs have evolved very rapidly; however, some groups of marine molluscs appear to be decreasing in the number of species existing.
Today, molluscs live in almost all parts of the world. From the deepest ocean trenches to high up on our mountains, molluscs have found their niche. The number of living species ranges from a very conservative 50,000 according to Brusca & Brusca (Invertebrates 1990) to 60,00 in Rupert & Barnes Invertebrate Zoology (sixth edition 1994) to 100,000 in Kozloff's Invertebrates (1990). That said, it is quite likely that up to half a million species will eventually be formally discovered (see the article on How to name a Species, for how this is done!), since many environments and the deeper parts of the sea-floor are very poorly known even today! Classification and taxonomy of molluscs can vary widely depending on what school of thought.
One thing does remain constant in all molluscs however; - to survive all molluscs must have moisture. To stay alive, they must keep their soft bodies moist at all times and for some like those which live in hot dry deserts environments, this is done by curling up in their shell, secreting a mucous plug and staying holed up until the next bit of moisture comes along.
What is a Mollusc?
The word "mollusc" or "mollusk" (both are correct) is derived from the Latin word mollis meaning "soft". The study of molluscs, "malacology", comes from the Greek word for soft, malacos. The term "conchology" is also used for the study of molluscs; however, it is usually applied to those that study the shell only.
Molluscs, in general, are soft-bodied animals that usually produce an external skeleton (called an "exoskeleton") we call a Shell, which is composed of a limey material: calcium carbonate (CaCO3) The shell serves both protective, and supportive purposes. The one feature common to all molluscs is the presence of a fleshy mantle. This is a fold or lobe (or a pair of them) of fleshy material, which secretes, modifies and lines the shell.
Members of all classes except the bivalves possess a ribbon-like set of hooked teeth called radula. These they rasp (think of a fingernail file) back and forth over their food much the same idea as a cat lapping up milk: Vegetarian species use them to scrape algae off rocks and other substrates, while most molluscan carnivores use them to penetrate the surface of their prey - even when that is a decent thickness of shell!
In the superfamily Conoidea (which includes the Cones and the largest family in the mollusc world the Turridae), the radula is specialized into a form of miniature "harpoon", which is used to spear prey, and in many cases, to deliver powerful neurotoxins, to paralyze their hapless victims.
Turris babylonia
(Linne, 1758 )
Picture courtesy of Ross Mayhew
Miscellaneous Conidae
Picture coutesy of Paul Monfils
Most molluscs have a well-defined nervous system with a primitive brain. Molluscs have a circulatory system and most have a two-chambered heart. Their digestive system usually includes a jaw, pharynx, esophagus, stomach, intestine and anus. They have a reproductive system that produces eggs and/or sperm. Most gastropods and cephalopods have eyes and tentacles.
The Molluscs we recognize today are divided into seven divisions called "classes"
Let us take a very brief look at these classes now:
• The POLYPLACOPHORA contain about 900 living species and are commonly known as chitons. They have a shell consisting of eight, usually overlapping plates, held together by a leathery "girdle". The animal is bilaterally symmetrical. With a well-developed foot surrounded by a groove in which there are 6 to 88 pairs of gills.
Tonicella insignis (Reeve, 1847)
The head lacks eyes and tentacles, but usually has light-sensitive areas and chemical receptors,for finding food and heading in the proper direction! All chitons are marine inhabitants and most make a living by grazing algae from rocks and other hard substrates. The great majority of them dwell in shallow and intertidal waters, but a few occur in depths down to 5,000+ meters. They range in length from 3 to 400+ millimeters. (1/8" to 1ft 4"+).
• The APLACOPHORA consist of about 250 living species (perhaps more, as they are relatively poorly studied!) of marine, wormlike, bilaterally symmetrical animals living at moderate, to very great depths, usually on or in soft bottoms. They have no shell, but have calcareous spicules in the body surface. The foot is restricted to an anterior pedal shield or to a narrow groove running the length of the body. Aplacophorans have a radula and a posterior mantle cavity. Some are detritus feeders, others are predators. They range in length from 1 to 300 millimeters. (If you read and go along with the views held by Brusca & Brusca (see bibliography) you will also include the Class of Caudofoveata & Solenogastres. These are two very small classes that many scientists combine to form the Class Aplacophora.
The Caudofoveata are aberrant molluscs that lack shells. They are quite common in the deep sea buried in the soft sediments. The Solenogastres also lack shells, are also found in very deep water and generally live on the surface of the substratum.)
• The SCAPHOPODA comprise about 350 living species. Commonly known as "tusk shells", they are bilaterally symmetrical and their elongate, tubular, tapering shells are open at both ends. The conical foot can be protruded for use in burrowing only. The head is rudimentary and lacks eyes and tentacles. It feeds by contractile filaments called captacula, which are withdrawn into the body cavity when they meet up with food. All scaphopoda are marine, and live buried in muddy or sandy bottoms, where they feed on detritus. They range from 2 to 150 millimeters (i.e., up to 6").
Dentalium (Dentalium) elephantinum
(Linnaeus, )1758
• The CEPHALOPODA contain about 600 to 650 living species. This class includes octopus, squid, cuttlefish and nautilus. They are bilaterally symmetrical and often highly streamlined. Tentacles surround the head, and a funnel coming from the mantle produces jet propulsion. Only a few cephalopoda produce a calcareous shell. They have an advanced nervous system and are the most intelligent (See Octopuses are Smart Suckers article) of all the invertebrates. All are marine inhabitants and are predators or scavengers. They range in size from 10 millimeters to 20 meters for the giant squid.
Chambered Nautilus
• The GASTROPODA is by far the most successful class of all the molluscs, with at least 60,000 living species. Gastropods generally have a single-valved shell, which is usually spiraled; however, this is absent in the slugs and semi-slugs. They have a head with cephalic tentacles and a well-developed foot used in crawling. Some gastropods have lungs for respiration, others gills.
Early in their larval stage of development, the visceral mass and mantle cavity rotate up to 180 degrees counterclockwise; in a process know as torsion. (This does not occur in some of the slugs though.) This brings their organs from a posterior position to an anterior position behind their head. In most cases, the soft animal is able to retract into their shells for protection. Some gastropods also have an operculum (trap door) connected to their foot that they can pull in after their soft body parts sealing off their shell from the environmental hazards or as protection from enemies. Gastropods are very successful in marine, freshwater and terrestrial habitats. Their size is from 0.5 to 750 millimeters. (i.e., up to 2 1/2 feet long)
• The BIVALVA, or PELECYPODA (the Bivalves) comprise about 10,000 living species. They have two valves made of calcium carbonate (in a hard form called "aragonite"), connected by a flexible ligament and an "adductor muscle" for closing the valves tightly.
The mantle cavity is enlarged, enclosing the visceral mass and other internal organs. There is no differentiated head or cephalic region, and the radula common to all other molluscs is absent. Most are filter feeders, with the gill acting as a food collecting and sorting organ, in addition to filling its respiratory function. The mouth usually has a pair of labial palps on either side that handle and direct the food collected by their gills. Bivalves inhabit all of the world's marine and freshwater habitats which have a pH greater than about 5 - any more acidic than that, and they can't form a shell fast enough to prevent it from being dissolved again! They range in size from 0.5 millimeters to almost 1.4 meters (that's 1400mm, or 4'8"!!)
• The MONOPLACOPHORA are mostly are known by their fossil records; however, there are about a dozen living species today. They have several foot retractor muscles, gills, and hearts similar to those of the annelid worms; however, their bodies are not segmented. All Monoplacophorans are marine inhabitants grazing on algae and microorganisms on the hard ocean bottom. They live at depths of 200 to 6,000 meters and they range in size from 2 to 35 millimeters.
Now Let's Take a More Detailed Look at The Phylum Mollusca
A phylum is usually defined as group of animals having several features common to all or most of its members. The following features are common amongst most molluscs:
Biologists use various methods for estimating how closely species are related to each other. They look at comparative anatomy, genetics and paleontology (the study of fossil organisms) to help form their theories. Changes within a population (a group of organisms of one species) generally occur due to divergence and speciation.
Divergence within a phylum can occur whenever the population is split into two or more groups with no chance of interbreeding. Divergence is generally brought about by such events as habitat changes or competition for food.
Speciation can result from reproductive isolation (populations can be physically isolated, as in many marine species, without being isolated reproductively, due to larval (veliger) stages which can drift for long distances, thus effectively "connecting" geographically remote populations. On the other hand, behavioral, morphological or reproductive differences in a small segment of a population can gradually lead to reproductive isolation, without much physical segregation. These reproductively separated populations will adapt to different conditions in different regions, via "natural selection" (i.e., survival of the fittest!). They may develop different mating behaviors or breeding seasons, or they may accumulate enough genetic differences to render egg and sperm incompatible. It is due to an accumulation of these changes and other morphological and genetic differences that we have the seven classes of molluscs today. This seemingly advanced degree of differentiation, however, took place hundreds of millions of years ago: by the middle of the Ordovician period, all the shell-bearing classes (6) of mollusc are represented in the fossil record.
Now, let's take an even closer look at these seven classes of molluscs. We'll cover the basic anatomy and physiology and behavior of each group, and a variety of other interesting facts about each. Enjoy!
The two first two classes we will discuss - the Aplacophorans and the Polyplacophorans, are often regarded by some as Subclasses of a larger Class called Amphineura: (Amphineura: (am-phi-neur-a) Latin: amphi =both. neura =nerve).
However, we will follow the crowd (i.e., the majority of scientists), and treat them separately.
Anatomy and Physiology of the Classes
References Used
To Next Page
To Top of Page
This is a new counter system set up by Globel on
December 01, 2002
|
<urn:uuid:5a9f8a05-ba65-4541-8e82-5a3733c618b5>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.671875,
"fasttext_score": 0.06023585796356201,
"language": "en",
"language_score": 0.9316132664680481,
"url": "http://manandmollusc.net/advanced_introduction/mollusca_101_intro.html"
}
|
Home Page
Understanding and using doing words
(verbs) in simple sentences
Why is this important?
This activity encourages children to build sentences using two key words: it
also helps to widen vocabulary.
This is an important step in the development of grammar.
What to do
• You will need:
★ Teddy and doll (or two other favourite toys).
★ Cup, brush, item of food, flannel.
• Put out teddy and doll and two different items (e.g. cup and flannel). Say:
★ ‘Make teddy drink.’
★ ‘Wash doll.’
★ ‘Make doll drink.’
• You could also ask the child to make doll or teddy perform an action that doesn’t
need any additional items (e.g. sleep, run, hop, sit, wave, clap).
★ ‘Make teddy jump.’
★ ‘Make teddy sit.’
★ ‘Make doll sleep.’
• When the child has successfully followed an instruction,
ask ‘What’s happening?’
Encourage the child to use a two-word phrase to describe
(e.g. ‘teddy jump’, ‘doll drink’).
• If the child doesn’t respond or uses a single-word (e.g. ‘jump’), offer a choice:
★ Adult: ‘Make teddy jump.’
★ Child follows instruction correctly.
★ Adult praises: ‘Well done. What’s happening?’ (points to teddy).
★ Child: ‘Teddy.’
★ Adult: ‘Is teddy sleeping or teddy jumping?’
★ Child: ‘Teddy jump.’
|
<urn:uuid:05851e05-a043-4b04-8eee-897eafd323cf>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 5,
"edu_score": 4.65625,
"fasttext_score": 0.05791288614273071,
"language": "en",
"language_score": 0.7357566952705383,
"url": "https://www.theberkeleycheshire.co.uk/46/"
}
|
Lady Jane Grey is proclaimed Queen (Day 1)
mary jane
(public domain)
King Edward VI had died on 6 July 1553, but his device for the succession was not implemented until 9 July when Jane was informed she was now Queen. Her reply was, “The crown is not my right, and pleaseth me not. The Lady Mary is the rightful heir.”
She was proclaimed Queen the very next day. The days in between were used by Jane’s father-in-law, John Dudley, 1st Duke of Northumberland to gather troops. Jane took up residence in the Tower of London. Her husband then asked her to declare him King, which she refused. She wished to make him a Duke, but it caused an argument between the two.
Meanwhile, Mary had also been informed of her brother’s death. She was established at Kenninghall when the news was confirmed. She had managed to evade the Duke of Northumberland so far. She addressed her household with the words that the right to the crown of England had descended to her by divine and by human law. Her household cheered her on. Her letter to the privy council arrived in London later that evening.
She declared herself to be Queen, and she asked that violence be avoided. Jane was informed of the letter and heard its content. Upon their allegiance, they were to “case our right and title to the crown and government of this realm to be proclaimed in our city of London, and other places as your wisdom shall seem good.” It was just one of the letters Mary sent. She called upon her loyal subjects to proclaim her Queen and requested forces to come to her aid.
A country that had never had a female ruler before suddenly had two. Jane did not respond to the letter, though it was later decided that someone should go and meet with Mary.
About Moniek Bloks 2122 Articles
Be the first to comment
Leave a Reply
Your email address will not be published.
|
<urn:uuid:f203a6f1-d856-42ac-a771-88e1567382af>
|
{
"dataset": "HuggingFaceTB/dclm-edu",
"edu_int_score": 4,
"edu_score": 3.515625,
"fasttext_score": 0.024638473987579346,
"language": "en",
"language_score": 0.9916667342185974,
"url": "https://www.historyofroyalwomen.com/the-royal-women/year-mary-lady-jane-grey-proclaimed-queen-day-1/"
}
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.