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https://en.wikipedia.org/wiki/Genomic%20island
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A genomic island (GI) is part of a genome that has evidence of horizontal origins. The term is usually used in microbiology, especially with regard to bacteria. A GI can code for many functions, can be involved in symbiosis or pathogenesis, and may help an organism's adaptation. Many sub-classes of GIs exist that are based on the function that they confer. For example, a GI associated with pathogenesis is often called a pathogenicity island (PAIs), while GIs that contain many antibiotic resistant genes are referred to as antibiotic resistance islands. The same GI can occur in distantly related species as a result of various types of lateral gene transfer (transformation, conjugation, transduction). This can be determined by base composition analysis, as well as phylogeny estimations.
Computational prediction
Various genomic island predictions programs have been developed. These tools can be broadly grouped into sequence based methods and comparative genomics/phylogeny based methods.
Sequence based methods depend on the naturally occurring variation that exists between the genome sequence composition of different species. Genomic regions that show abnormal sequence composition (such as nucleotide bias or codon bias) suggests that these regions may have been horizontally transferred. Two major problems with these methods are that false predictions can occur due to natural variation in the genome (sometimes due to highly expressed genes) and that horizontally transferred DNA will ameliorate (change to the host genome) over time; therefore, limiting predictions to only recently acquired GIs.
Comparative genomics based methods try to identify regions that show signs that they have been horizontally transferred using information from several related species. For example, a genomic region that is present in one species, but is not present in several other related species suggests that the region may have been horizontally transferred. The alternative explanations are
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https://en.wikipedia.org/wiki/Four-vertex%20theorem
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The four-vertex theorem of geometry states that the curvature along a simple, closed, smooth plane curve has at least four local extrema (specifically, at least two local maxima and at least two local minima). The name of the theorem derives from the convention of calling an extreme point of the curvature function a vertex. This theorem has many generalizations, including a version for space curves where a vertex is defined as a point of vanishing torsion.
Definition and examples
The curvature at any point of a smooth curve in the plane can be defined as the reciprocal of the radius of an osculating circle at that point, or as the norm of the second derivative of a parametric representation of the curve, parameterized consistently with the length along the curve. For the vertices of a curve to be well-defined, the curvature itself should vary continuously, as happens for curves of smoothness . A vertex is then a local maximum or local minimum of curvature. If the curvature is constant over an arc of the curve, all points of that arc are considered to be vertices. The four-vertex theorem states that a smooth closed curve always has at least four vertices.
An ellipse has exactly four vertices: two local maxima of curvature where it is crossed by the major axis of the ellipse, and two local minima of curvature where it is crossed by the minor axis. In a circle, every point is both a local maximum and a local minimum of curvature, so there are infinitely many vertices.
Every curve of constant width has at least six vertices. Although many curves of constant width, such as the Reuleaux triangle, are non-smooth or have circular arcs on their boundaries, there exist smooth curves of constant width that have exactly six vertices.
History
The four-vertex theorem was first proved for convex curves (i.e. curves with strictly positive curvature) in 1909 by Syamadas Mukhopadhyaya. His proof utilizes the fact that a point on the curve is an extremum of the curvature function
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https://en.wikipedia.org/wiki/VESA%20Plug%20and%20Display
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VESA Plug and Display (abbreviated as P&D) is a video connector that carries digital signals for monitors, such as flat panel displays and video projectors, ratified by Video Electronics Standards Association (VESA) in 1997. Introduced around the same time as the competing connectors for the Digital Visual Interface (DVI, 1999) and VESA's own Digital Flat Panel (DFP, 1999), it was marketed as a replacement for the VESA Enhanced Video Connector (EVC, 1994). Unlike DVI, it never achieved widespread implementation.
The P&D connector shares the 30-pin plus quad-coax layout of EVC, which carries digital video, analog video, and data over Universal Serial Bus (USB) and IEEE 1394 (FireWire). At a minimum, the P&D connector is required to carry digital video, in which case the connector is designated P&D-D; when both digital and analog video are included, the connector is designated P&D-A/D.
Design
The P&D receptacle and plug are required to bear a standardized symbol to designate the standards with which it is compatible. The upper left quadrant designates analog video support. The upper right quadrant designates digital video support. The lower quadrants designate IEEE 1394 and USB support.
All P&D connectors are required to carry single-link TMDS digital video signal (max 160 MHz), and support VESA Display Data Channel version 2 at a minimum. Maximum resolution is 1600×1280 with a 60 Hz refresh rate.
Analogue video signals, if supported, must be provided as three separate color channels (red / green / blue) along with one composite or two (horizontal & vertical) sync signals. The nominal impedance of each signal line is 75 Ω and each channel must be capable of carrying a bandwidth of at least 2.4 GHz. The type designation for the analogue video signals designates the voltage values of the signals only, including the Type 4 (VESA) analog DC protocol introduced with EVC:
The P&D connector supports optional charging power at 18–20 VDC and up to 1.5 A. In addition, a s
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https://en.wikipedia.org/wiki/Dictionary%20of%20the%20Scots%20Language
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The Dictionary of the Scots Language (DSL) (, ) is an online Scots–English dictionary, now run by Dictionaries of the Scots Language, formerly known as Scottish Language Dictionaries, a registered SCIO charity. Freely available via the Internet, the work comprises the two major dictionaries of the Scots language:
Dictionary of the Older Scottish Tongue (DOST), 12 volumes
Scottish National Dictionary (SND), 10 volumes
The DOST contains information about Older Scots words in use from the 12th to the end of the 17th centuries (Early and Middle Scots); SND contains information about Scots words in use from 1700 to the 1970s (Modern Scots). Together these 22 volumes provide a comprehensive history of Scots. The SND Bibliography and the DOST Register of Titles have also been digitised and can be searched in the same way as the main data files. A new supplement compiled by Scottish Language Dictionaries was added in 2005.
The digitisation project, which ran from February 2001 to January 2004, was based at the University of Dundee and primarily funded by a grant from the Arts and Humanities Research Board, with additional support provided by the Scottish National Dictionary Association and the Russell Trust. The project team was led by academic, Dr Victor Skretkowicz and lexicographer, Susan Rennie, a former Senior Editor with the Scottish National Dictionary Association. Its methodology was based on a previous, pilot project by Rennie to digitise the Scottish National Dictionary (the eSND project), using a customised XML markup based on Text Encoding Initiative guidelines. The Dictionary of the Scots Language data was later used to create sample categories for a new Historical Thesaurus of Scots project, led by Rennie at the University of Glasgow, which was launched in 2015.
Dr Victor Skretkowicz was born in Hamilton, Ontario, in 1942; joined the University of Dundee's English Department in 1978 and in 1989, became the Dundee University's representative on the Joint Coun
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https://en.wikipedia.org/wiki/Salicylate%20testing
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Salicylate testing is a category of drug testing that is focused on detecting salicylates such as acetysalicylic acid for either biochemical or medical purposes.
Analytical
Salicylates can be identified by GC/MS, proton NMR, and IR.
In vitro
One of the first in vitro tests for aspirin was through the Trinder reaction. Aqueous ferric chloride was added to a urine sample, and the formation of the iron complex turned the solution purple. This test was not specific to acetylsalicylic acid but would occur in the presence of any phenol or enol. The downfall of this test occurs in the presence of hyperbilirubinemia or elevated bilirubin. When the level of bilirubin exceeds 1 mg/dl, a false positive could occur.
Enzyme Specific Assay
The current in vitro testing utilizes molecule specific methods of detecting salicylates.
Immunoassay
Another identification mechanism is through immunoassay. Abbott Labs' AxSYM is an immunoassay device utilizing Fluorescence Polarization Immunoassay (FPIA) technology that can determine the presence and quantify salicylates. The introduction of a salicylate specific antigen labeled with fluorescein into the sample will mark the sample. Upon irradiation with 490nm light, some of that light will be reflected back to a detector at 520nm. Polarization allows the machine to detect the difference between antibody bound, and unbound fluorescein. It is therefore possible to quantify the serum salicylate level through the signal strength—the amount of reflected light received.
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https://en.wikipedia.org/wiki/Transverse%20cervical%20nerve
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The transverse cervical nerve (superficial cervical or cutaneous cervical) is a cutaneous (sensory) nerve of the cervical plexus that arises from the second and third cervical spinal nerves (C2-C3). It curves around the posterior border of the sternocleidomastoideus muscle, then pierces the fascia of the neck before dividing into two branches. It provides sensory innervation to the front of the neck.
Anatomy
Course and relations
It curves around the posterior border of the sternocleidomastoideus muscle about its middle, and, passing obliquely forward beneath the external jugular vein to the anterior border of the muscle, it perforates the deep cervical fascia before dividing into an ascending branch and a descending branch beneath the platysma. The ascending branch communicates with the cervical branch of the facial nerve.
Dissection
During dissection, the sternocleidomastoid muscle is the landmark, with the transverse cervical nerve passing horizontally over this muscle from Erb's point.
Distribution
The nerve provides sensory innervation to the skin of the anterior neck between the chin and the sternum.
Additional images
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https://en.wikipedia.org/wiki/Middle%20nasal%20concha
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The medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha (middle nasal turbinate).
It is rough, and marked above by numerous grooves, directed nearly vertically downward from the cribriform plate; they lodge branches of the olfactory nerves, which are distributed to the mucous membrane covering the superior nasal concha.
Additional images
See also
Nasal concha
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https://en.wikipedia.org/wiki/Spur%20%28architecture%29
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In architecture, a spur (French , German ) is the ornament carved on the angles of the base of early columns.
Ornament
A spur consists of a projecting claw, which, emerging from the lower torus of the base, rests on the projecting angle of the square plinth.
Ancient Roman architecture
It is possibly to these that Pliny refers (Hist. Nat. XXVI. 42) when speaking of the lizard and frog carved on the bases (spirae) of the columns of the temples of Jupiter and Juno in the Portico of Octavius; the earliest known example is that of Diocletian's Palace at Split.
In Romanesque work the oldest examples are those found on the bases in crypts, where they assumed various conventional forms; being, however, close to the eye, the spur soon developed into an elaborate leaf ornament, which in French 13th-century work and in the early English period is of great beauty; sometimes the spur takes the form of a fabulous animal, such as a griffin.
See also
Architectural sculpture
Notes
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https://en.wikipedia.org/wiki/Ethmoid%20bulla
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The ethmoid bulla (or ethmoidal bulla) is a rounded elevation upon the lateral wall of the middle nasal meatus (nasal cavity inferior to the middle nasal concha) produced by one or more of the underlying middle ethmoidal air cells (which open into the nasal cavity upon or superior to the ethmoidal bulla). It varies significantly based on the size of the underlying air cells.
Structure
The ethmoid bulla is formed by is the largest and least variable of the middle ethmoidal air cells. The size of the bulla varies with that of its contained cells. The bulla may be a pneumatised cell or a bony prominence found in middle meatus.
Relations
The hiatus semilunaris is situated (sources differ) inferior/anterior to the ethmoid bulla. The maxillary sinus also opens below the bulla.
Development
The ethmoid bulla begins to develop between 8 weeks and 12 weeks of gestation.
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https://en.wikipedia.org/wiki/Tera%20Term
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Tera Term (alternatively TeraTerm) is an open-source, free, software implemented, terminal emulator (communications) program. It emulates different types of computer terminals, from DEC VT100 to DEC VT382. It supports Telnet, SSH 1 & 2 and serial port connections. It also has a built-in macro scripting language (supporting Oniguruma regular expressions) and a few other useful plugins.
History
The first versions of Tera Term were created by T. Teranishi from Japan. At the time, it was the only freely available terminal emulator to effectively support the Japanese language. Original development of Tera Term stopped in the late 1990s at version 2.3, but other organizations have created variations.
In October 2002, Ayera Technologies released TeraTerm Pro 3.1.3 supporting SSH2 and added multiple other features like a built-in web server for API integration with external systems, recurring "keep-alive" commands, and ODBC database support via the TT Macro Scripting Language. Ayera Technologies did not make their source open, but does provide limited technical support.
In 2004, Yutaka Hirata, a software designer from Japan, restarted development of the open source version of Tera Term. He added his own implementation of SSH2 and many new features on top of what was part of version 2.3.
To avoid confusion with version numbers and to indicate that Tera Term developed by Yutaka was more recent than version 3.1.3 from Ayera Technologies, it was decided to give this branch of Tera Term Professional version numbers starting 4.xx.
In January 2005, Boris Maisuradze, together with Yutaka Hirata, started the TeraTerm Support forum where they answered questions from Tera Term users. Posting in this forum was the best way to suggest new features for Tera Term or propose new commands for the Tera Term Macro language. For more than 10 years the forum was hosted on LogMeTT.com website maintained by Boris Maisuradze. Boris also developed several freeware tools that became part of Ter
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https://en.wikipedia.org/wiki/Submandibular%20duct
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The submandibular duct (also Wharton's duct or historically submaxillary duct) is one of the salivary excretory ducts. It is about 5 cm long, and its wall is much thinner than that of the parotid duct. It drains saliva from each bilateral submandibular gland and sublingual gland to the sublingual caruncle in the floor of the mouth.
Structure
The submandibular duct arises from deep part of submandibular gland, a salivary gland. It begins by numerous branches from the superficial surface of the gland, and runs forward between the mylohyoid, hyoglossus, and genioglossus muscles. It then passes between the sublingual gland and the genioglossus and opens by a narrow opening on the summit of a small papilla (the "sublingual caruncle") at the side of the frenulum of the tongue. It lies superior to lingual and hypoglossal nerves.
Variation
The submandibular duct may be duplicated on one side or both sides, creating an accessory submandibular duct. Rarely, it may not perforate into the mouth.
Function
The submandibular ducts drain saliva from the submandibular gland, and the sublingual glands to the sublingual caruncles in the floor of the mouth
Clinical significance
Sialolithiasis
The submandibular duct may be affected by stones, known as sialolithiasis. These may grow large, requiring surgery to remove. Simple palpation may be used to identify the location of any stones before surgery.
Imperforate
Rarely, the submandibular duct may not perforate into the mouth. Surgery may be used to repair this birth defect.
Drooling
The exit of the submandibular gland into the mouth may be realigned in patients who drool. This redirects the exiting saliva away from the vestibule and the lips. This surgery has a fairly high success rate. Rarely, the submandibular gland may need to be removed on one or both sides.
History
The submandibular duct was initially described by the English anatomist Thomas Wharton ( 1614-73) and is sometimes referred to by his name.
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https://en.wikipedia.org/wiki/Plants%20for%20a%20Future
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Plants For A Future (PFAF) is an online not for profit resource for those interested in edible and useful plants, with a focus on temperate regions. Named after the phrase "plans for a future" as wordplay, the organization's emphasis is on perennial plants.
PFAF is a registered educational charity with the following objectives:
The website contains an online database of over 8000 plants: 7000 that can be grown in temperate regions including in the UK, and 1000 plants for tropical situations.
The database was originally set up by Ken Fern to include 1,500 plants which he had grown on his 28 acre research site in the South West of England.
Since 2008, the database has been maintained by the database administrator employed by the Plants For A Future Charity.
The organization participates in public discussion by publishing books. Members have participated in various conferences and are also participants in the International Permaculture Research Project.
Publications
Fern, Ken. Plants for a Future: Edible and Useful Plants for a Healthier World. Hampshire: Permanent Publications, 1997. .
Edible Plants: An inspirational guide to choosing and growing unusual edible plants. 2012
Woodland Gardening: Designing a low-maintenance, sustainable edible woodland garden. 2013.
Edible Trees: A practical and inspirational guide from Plants For A Future on how to grow and harvest trees with edible and other useful produce. 2013.
Plantes Comestibles: Le guide pour vous inspirer à choisir et cultiver des plantes comestibles hors du commun. 2014.
Edible Perennials: 50 Top perennial plants from Plants For A Future. 2015.
Edible Shrubs: 70+ Top Shrubs from Plants For A Future
Plants for Your Food Forest: 500 Plants for Temperate Food Forests and Permaculture Gardens. 2021.
See also
Forest gardening
Postcode Plants Database
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https://en.wikipedia.org/wiki/Sympathetic%20trunk
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The sympathetic trunks (sympathetic chain, gangliated cord) are a paired bundle of nerve fibers that run from the base of the skull to the coccyx. They are a major component of the sympathetic nervous system.
Structure
The sympathetic trunk lies just lateral to the vertebral bodies for the entire length of the vertebral column. It interacts with the anterior rami of spinal nerves by way of rami communicantes. The sympathetic trunk permits preganglionic fibers of the sympathetic nervous system to ascend to spinal levels superior to T1 and descend to spinal levels inferior to L2/3.
The superior end of it is continued upward through the carotid canal into the skull, and forms a plexus on the internal carotid artery; the inferior part travels in front of the coccyx, where it converges with the other trunk at a structure known as the ganglion impar.
Along the length of the sympathetic trunk are sympathetic ganglia known as paravertebral ganglia.
Relations
In the cervical region, the sympathetic trunk is situated upon the prevertebral fascia posterior to the carotid sheath.
Function
The sympathetic trunk is a fundamental part of the sympathetic nervous system, and part of the autonomic nervous system. It allows nerve fibres to travel to spinal nerves that are superior and inferior to the one in which they originated. Also, a number of nerves, such as most of the splanchnic nerves, arise directly from the trunks.
Additional images
See also
Horner's syndrome
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https://en.wikipedia.org/wiki/Pterygoid%20hamulus
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The pterygoid hamulus is a hook-like process at the lower extremity of the medial pterygoid plate of the sphenoid bone of the skull. It is the superior origin of the pterygomandibular raphe, and the levator veli palatini muscle.
Structure
The pterygoid hamulus is part of the medial pterygoid plate of the sphenoid bone of the skull. Its tip is rounded off. It has an average length of 7.2 mm, an average depth of 1.4 mm, and an average width of 2.3 mm. The tendon of tensor veli palatini muscle glides around it.
Function
The pterygoid hamulus is the superior origin of the pterygomandibular raphe. It is also the origin of levator veli palatini muscle.
Clinical significance
Rarely, the pterygoid hamulus may be enlarged, which may cause mouth pain.
See also
Hamulus
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https://en.wikipedia.org/wiki/Hamulus
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A hamus or hamulus is a structure functioning as, or in the form of, hooks or hooklets.
Etymology
The terms are directly from Latin, in which hamus means "hook". The plural is hami.
Hamulus is the diminutive – hooklet or little hook. The plural is hamuli.
Adjectives are hamate and hamulate, as in "a hamulate wing-coupling", in which the wings of certain insects in flight are joined by hooking hamuli on one wing into folds on a matching wing. Hamulate can also mean "having hamuli". The terms hamose, hamular, hamous and hamiform also have been used to mean "hooked", or "hook-shaped". Terms such as hamate that do not indicate a diminutive usually refer particularly to a hook at the tip, whereas diminutive terms such as hamulose tend to imply that something is beset with small hooks.
Anatomy
In vertebrate anatomy, a hamulus is a small, hook-shaped portion of a bone, or possibly of other hard tissue.
In human anatomy, examples include:
pterygoid hamulus
hamulus of hamate bone
lacrimal hamulus
Arthropoda
In arthropod morphology hamuli are hooklets, usually in the form of projections of the surface of the exoskeleton. Hami might be actual evaginations of the whole thickness of the exoskeleton. The best-known examples are probably the row of hamuli on the anterior edge of the metathoracic (rear) wings of Hymenoptera such as the honeybee. The hooks attach to a fold on the posterior edge of the mesothoracic (front) wings.
It is less widely realised that similar hamuli, though usually fewer, are used in wing coupling in the Sternorrhyncha, the suborder of aphids and scale insects. In the Sternorrhyncha such wing coupling occurs particularly in the males of some species. The rear wings of that suborder frequently are reduced or absent, and in many species the last vestige of the rear wing to persist is a futile little strap holding the hamuli, still hooking into the fold of the large front wings.
In those Springtails (Collembola) that have a functional furcula, the
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https://en.wikipedia.org/wiki/Postcode%20Plants%20Database
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The Postcode Plants Database was a UK resource for identifying locally native plants and species based on postcode, hosted by the Natural History Museum in London.
This resource has been replaced by the analysis pages on the NBN Atlas website. There you can choose to display any groups of UK wildlife within a radius of any given post-code.
See also
Plants for a Future – online plant database
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https://en.wikipedia.org/wiki/Mylohyoid%20nerve
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The mylohyoid nerve (or nerve to mylohyoid) is a mixed nerve of the head. It is a branch of the inferior alveolar nerve. It provides motor innervation the mylohyoid muscle, and the anterior belly of the digastric muscle. It provides sensory innervation to part of the submental area, and sometimes also the mandibular (lower) molar teeth, requiring local anaesthesia for some oral procedures.
Structure
Origin
The mylohyoid nerve is a mixed (motor-sensory) branch of the inferior alveolar nerve (which is a branch of the mandibular nerve (CN V3) that is itself a branch of the trigeminal nerve (CN V)). It arises just before it enters the mandibular foramen.
Course
It pierces the sphenomandibular ligament. It descends in a groove on the deep surface of the ramus of the mandible. When it reaches the under surface of the mylohyoid muscle, it gives branches to the mylohyoid muscle and the anterior belly of the digastric muscle.
Distribution
Motor
The mylohyoid nerve supplies the mylohyoid muscle and the anterior belly of the digastric muscle.
Sensory
It provides sensory innervation to the skin of the centre of the submental area. It may also provide some sensory innervation to the mandibular (lower) molar teeth.
Clinical significance
The mylohyoid nerve needs to be blocked during local anaesthesia of the mandibular (lower) teeth to prevent pain during oral procedures. It may not be anaesthetised during a block of the inferior alveolar nerve, causing pain.
Additional images
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https://en.wikipedia.org/wiki/Retropharyngeal%20space
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The retropharyngeal space (abbreviated as "RPS") is a potential space and deep compartment of the head and neck situated posterior to the pharynx. The RPS is bounded anteriorly by the buccopharyngeal fascia, posteriorly by the alar fascia, and laterally by the carotid sheath. It extends between the base of the skull superiorly, and the mediastinum inferiorly. It contains the retropharyngeal lymph nodes. Its function is to facilitate movements in the superoinferior axis of the larynx, pharynx, and esophagus in relation to the cervical spine.
Sources consider the retropharyngeal space to be in principle subdivided into the so-called "true retropharyngeal space" or "retropharyngeal space proper" (part of the RSP situated anterior to the alar fascia), and the danger space (part of the RSP situated posterior to the alar fascia). The danger space is sometimes also lumped together with the true RPS and the whole referred to as the RPS because the alar fascia is an ineffective barrier. Infections from the head and neck can spread down through the danger space into the posterior mediastinum.
Anatomy
Superiorly, the retropharingeal space terminates at the base of the skull (more specifically, at the clivus). Inferiorly, the true RPS terminates at a variable level along the upper thoracic spine with the fusion of alar fascia and visceral fascia; sources either give the inferior termination of the true RPS as occurring at approximately the vertebral level of T4 or at a variable level anywhere between the T1-T6. The danger space component of the RPS meanwhile extends further inferior-ward, entering the posterior mediastinum to reach the level of the diaphragm.
Contents
The retropharnygeal space contains the retropharyngeal lymph nodes, adipose tissue, and loose connective tissue. The suprahyoid portion of the RPS contains the lymph nodes as well as adipose tissue, while the infrahyoid portion contains adipose tissue only.
A midline raphe is sometimes present in the RPS, su
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https://en.wikipedia.org/wiki/Binary%20multiplier
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A binary multiplier is an electronic circuit used in digital electronics, such as a computer, to multiply two binary numbers.
A variety of computer arithmetic techniques can be used to implement a digital multiplier. Most techniques involve computing the set of partial products, which are then summed together using binary adders. This process is similar to long multiplication, except that it uses a base-2 (binary) numeral system.
History
Between 1947 and 1949 Arthur Alec Robinson worked for English Electric Ltd, as a student apprentice, and then as a development engineer. Crucially during this period he studied for a PhD degree at the University of Manchester, where he worked on the design of the hardware multiplier for the early Mark 1 computer.
However, until the late 1970s, most minicomputers did not have a multiply instruction, and so programmers used a "multiply routine"
which repeatedly shifts and accumulates partial results,
often written using loop unwinding. Mainframe computers had multiply instructions, but they did the same sorts of shifts and adds as a "multiply routine".
Early microprocessors also had no multiply instruction. Though the multiply instruction became common with the 16-bit generation,
at least two 8-bit processors have a multiply instruction: the Motorola 6809, introduced in 1978, and Intel MCS-51 family, developed in 1980, and later the modern Atmel AVR 8-bit microprocessors present in the ATMega, ATTiny and ATXMega microcontrollers.
As more transistors per chip became available due to larger-scale integration, it became possible to put enough adders on a single chip to sum all the partial products at once, rather than reuse a single adder to handle each partial product one at a time.
Because some common digital signal processing algorithms spend most of their time multiplying, digital signal processor designers sacrifice considerable chip area in order to make the multiply as fast as possible; a single-cycle multiply–accumulate un
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https://en.wikipedia.org/wiki/Digital%20comparator
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A digital comparator or magnitude comparator is a hardware electronic device that takes two numbers as input in binary form and determines whether one number is greater than, less than or equal to the other number. Comparators are used in central processing units (CPUs) and microcontrollers (MCUs). Examples of digital comparator include the CMOS 4063 and 4585 and the TTL 7485 and 74682.
An XNOR gate is a basic comparator, because its output is "1" only if its two input bits are equal.
The analog equivalent of digital comparator is the voltage comparator. Many microcontrollers have analog comparators on some of their inputs that can be read or trigger an interrupt.
Implementation
Consider two 4-bit binary numbers A and B so
Here each subscript represents one of the digits in the numbers.
Equality
The binary numbers A and B will be equal if all the pairs of significant digits of both numbers are equal, i.e.,
, , and
Since the numbers are binary, the digits are either 0 or 1 and the boolean function for equality of any two digits and can be expressed as
we can also replace it by XNOR gate in digital electronics.
is 1 only if and are equal.
For the equality of A and B, all variables (for i=0,1,2,3) must be 1.
So the equality condition of A and B can be implemented using the AND operation as
The binary variable (A=B) is 1 only if all pairs of digits of the two numbers are equal.
Inequality
In order to manually determine the greater of two binary numbers, we inspect the relative magnitudes of pairs of significant digits, starting from the most significant bit, gradually proceeding towards lower significant bits until an inequality is found. When an inequality is found, if the corresponding bit of A is 1 and that of B is 0 then we conclude that A>B.
This sequential comparison can be expressed logically as:
(A>B) and (A < B) are output binary variables, which are equal to 1 when A>B or A<B respectively.
See also
List of LM-series integrated c
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https://en.wikipedia.org/wiki/Comet%20%28programming%29
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Comet is a web application model in which a long-held HTTPS request allows a web server to push data to a browser, without the browser explicitly requesting it. Comet is an umbrella term, encompassing multiple techniques for achieving this interaction. All these methods rely on features included by default in browsers, such as JavaScript, rather than on non-default plugins. The Comet approach differs from the original model of the web, in which a browser requests a complete web page at a time.
The use of Comet techniques in web development predates the use of the word Comet as a neologism for the collective techniques. Comet is known by several other names, including
Ajax Push,
Reverse Ajax, Two-way-web, HTTP Streaming, and
HTTP server push
among others. The term Comet is not an acronym, but was coined by Alex Russell in his 2006 blog post.
In recent years, the standardisation and widespread support of WebSocket and Server-sent events has rendered the Comet model obsolete.
History
Early Java applets
The ability to embed Java applets into browsers (starting with Netscape Navigator 2.0 in March 1996) made two-way sustained communications possible, using a raw TCP socket to communicate between the browser and the server. This socket can remain open as long as the browser is at the document hosting the applet. Event notifications can be sent in any format text or binary and decoded by the applet.
The first browser-to-browser communication framework
The very first application using browser-to-browser communications was Tango Interactive, implemented in 1996–98 at the Northeast Parallel Architectures Center (NPAC) at Syracuse University using DARPA funding. TANGO architecture has been patented by Syracuse University. TANGO framework has been extensively used as a distance education tool. The framework has been commercialized by CollabWorx and used in a dozen or so Command&Control and Training applications in the United States Department of Defense.
First Comet appli
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https://en.wikipedia.org/wiki/Maxillary%20hiatus
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The maxillary hiatus (also known as maxillary sinus ostium, maxillary ostium, or opening from the maxillary sinus) is the opening of a maxillary sinus into the middle nasal meatus of the nasal cavity. It is situated superoposteriorly upon the lateral nasal wall, opening into the nasal cavity at the posterior portion of the ethmoidal infundibulum. Its opening in the maxillary sinus is present upon the superior part of the medial wall of the sinus near the roof of the sinus; because of the position, gravity cannot drain the maxillary sinus contents when the head is erect.
An accessory maxillary hiatus may be present either anterior or posterior to the inferior portion of the uncinate process of ethmoid bone.
Anatomy
It measures 2–4 mm in diameter with an average diameter of 2.4 mm.
It opens into the nasal cavity inferior to the bulla ethmoidalis, and is partly obscured by the inferior end of the uncinate process of ethmoid bone.
The bone window of this aperture itself is much larger, but the actual opening is much reduced by the following: the uncinate process of the ethmoid superiorly, the ethmoidal process of inferior nasal concha inferiorly, the perpendicular plate of palatine bone posteriorly, and a small part of the lacrimal bone anteriorly and superiorly, as well as by the adjacent soft tissues.
Additional images
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https://en.wikipedia.org/wiki/Enriched%20text
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Enriched text is a formatted text format for e-mail, defined by the IETF in RFC 1896 and associated with the text/enriched MIME type which is defined in RFC 1563. It is "intended to facilitate the wider interoperation of simple enriched text across a wide variety of hardware and software platforms". As of 2012, enriched text remained almost unknown in e-mail traffic, while HTML e-mail is widely used. Enriched text, or at least the subset of HTML that can be transformed into enriched text, is seen as preferable to full HTML for use with e-mail (mainly because of security considerations).
A predecessor of this MIME type was called text/richtext in RFC 1341 and RFC 1521. Neither should be confused with Rich Text Format (MIME type text/rtf or application/rtf) which are unrelated specifications, devised by Microsoft.
A single newline in enriched text is treated as a space. Formatting commands are in the same style as SGML and HTML. They must be balanced and nested.
Enriched text is a supported format of Emacs, Mutt, Mulberry and Netscape Communicator.
Examples
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https://en.wikipedia.org/wiki/Martha%20%28passenger%20pigeon%29
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Martha ( – September 1, 1914) was the last known living passenger pigeon (Ectopistes migratorius); she was named "Martha" in honor of the first First Lady Martha Washington.
Early life
The history of the Cincinnati Zoo's passenger pigeons has been described by Arlie William Schorger in his monograph on the species as "hopelessly confused," and he also said that it is "difficult to find a more garbled history" than that of Martha. The generally accepted version is that, by the turn of the 20th century, the last known group of passenger pigeons was kept by Professor Charles Otis Whitman at the University of Chicago. Whitman originally acquired his passenger pigeons from David Whittaker of Wisconsin, who sent him six birds, two of which later bred and hatched Martha in about 1885. Martha was named in honor of Martha Washington. Whitman kept these pigeons to study their behavior, along with rock doves and Eurasian collared-doves. Whitman and the Cincinnati Zoo, recognizing the decline of the wild populations, attempted to consistently breed the surviving birds, including attempts at making a rock dove foster passenger pigeon eggs. These attempts were unsuccessful, and Whitman sent Martha to the Cincinnati Zoo in 1902.
However, other sources argue that Martha was instead the descendant of three pairs of passenger pigeons purchased by the Cincinnati Zoo in 1877. Another source claimed that when the Cincinnati Zoo opened in 1875, it already had 22 birds in its collection. These sources claim that Martha was hatched at the Cincinnati Zoo in 1885, and that the passenger pigeons were originally kept not because of the rarity of the species, but to enable guests to have a closer look at a native species.
Cincinnati Zoo
By November 1907, Martha and her two male companions at the Cincinnati Zoo were the only known surviving passenger pigeons after four captive males in Milwaukee died during the winter. One of the Cincinnati males died in April 1909, followed by the remaining
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https://en.wikipedia.org/wiki/CER-12
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CER ( – Digital Electronic Computer) model 12 was a third-generation digital computer developed by Mihajlo Pupin Institute (Serbia) in 1971 and intended for "business and statistical data processing" (see ref. Lit. #1 and #4). However, the manufacturer also stated, at the time, that having in mind its architecture and performance, it can also be used successfully in solving "wide array of scientific and technical issues" (ref. Lit.#2 and #3). Computer CER-12 consisted of multiple modules connected via wire wrap and connectors.
Central Unit
Primary memory
Type: magnetic core memory
Capacity: up to 8 modules, each consisting of 8 kilowords (1 word = 4 8-bit bytes).
Speed: cycle time: 1 μs, access time 0.4 μs.
Arithmetic unit contains:
32-bit accumulator register
two separate groups of eight 2-byte index registers
single-byte adder supporting both binary and BCD addition (same unit is used for subtraction, multiplication and division had to be implemented in software)
Control Unit
Control unit contains a program counter and instruction registers. It fetches instructions and facilitates program flow. It supports single-operand instruction set and works with all 16 index registers of the arithmetic unit.
Interrupt System
Interrupt system of CER-12 consists of a number of dedicated registers and software. It supports up to 32 interrupt channels.
Control Panel
Control panel of CER-12 allowed the operator to control and alter program flow and/or to eliminate errors detected by error-detection circuitry. It features a number of indicators and switches.
Operating system and other software
Following software was shipped with CER-12:
Operating System
"Symbolic programming language" and assembler (called "autocoder")
Input/output subroutines
A number of test programs
COBOL and FORTRAN IV compilers
Linear programming and PERT planning software
A library of applications and subroutines
Peripherals
5-8 track, 500 characters per second punched tape reader PE 10
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https://en.wikipedia.org/wiki/CER-20
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CER (Serbian: Цифарски Електронски Рачунар / Cifarski Elektronski Računar - Digital Electronic Computer) model 20 was an early digital computer developed by Mihajlo Pupin Institute (Serbia). It was designed as a functioning prototype of an "electronic bookkeeping machine". The first prototype was planned for 1964.
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https://en.wikipedia.org/wiki/Leaky%20integrator
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In mathematics, a leaky integrator equation is a specific differential equation, used to describe a component or system that takes the integral of an input, but gradually leaks a small amount of input over time. It appears commonly in hydraulics, electronics, and neuroscience where it can represent either a single neuron or a local population of neurons.
Equation
The equation is of the form
where C is the input and A is the rate of the 'leak'.
General solution
The equation is a nonhomogeneous first-order linear differential equation. For constant C its solution is
where is a constant encoding the initial condition.
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https://en.wikipedia.org/wiki/Maxillary%20artery
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The maxillary artery supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible.
Structure
The maxillary artery, the larger of the two terminal branches of the external carotid artery, arises behind the neck of the mandible, and is at first imbedded in the substance of the parotid gland; it passes forward between the ramus of the mandible and the sphenomandibular ligament, and then runs, either superficial or deep to the lateral pterygoid muscle, to the pterygopalatine fossa.
It supplies the deep structures of the face, and may be divided into mandibular, pterygoid, and pterygopalatine portions.
First portion
The first or mandibular or bony portion passes horizontally forward, between the neck of the mandible and the sphenomandibular ligament, where it lies parallel to and a little below the auriculotemporal nerve; it crosses the inferior alveolar nerve, and runs along the lower border of the lateral pterygoid muscle.
Branches include:
Deep auricular artery
Anterior tympanic artery
Middle meningeal artery
Inferior alveolar artery which gives off its mylohyoid branch just prior to entering the mandibular foramen
Accessory meningeal artery
Second portion
The second or pterygoid or muscular portion runs obliquely forward and upward under cover of the ramus of the mandible and insertion of the temporalis, on the superficial (very frequently on the deep) surface of the lateral pterygoid muscle; it then passes between the two heads of origin of this muscle and enters the fossa.
Branches include:
Masseteric artery
Pterygoid branches
Deep temporal arteries (anterior and posterior)
Buccal artery
Third portion
The third or pterygopalatine or pterygomaxillary portion lies in the pterygopalatine fossa in relation with the pterygopalatine ganglion. This is considered the terminal branch of the maxillary artery.
Branches include:
Sphenopalatine artery (nasopalatine artery) is the terminal branch of
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https://en.wikipedia.org/wiki/Descending%20palatine%20artery
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The descending palatine artery is a branch of the third part of the maxillary artery supplying the hard and soft palate.
Course
It descends through the greater palatine canal with the greater and lesser palatine branches of the pterygopalatine ganglion, and, emerging from the greater palatine foramen, runs forward in a groove on the medial side of the alveolar border of the hard palate to the incisive canal; the terminal branch of the artery passes upward through this canal to anastomose with the sphenopalatine artery.
Branches
Branches are distributed to the gums, the palatine glands, and the mucous membrane of the roof of the mouth; while in the pterygopalatine canal it gives off twigs which descend in the lesser palatine canals to supply the soft palate and palatine tonsil, anastomosing with the ascending palatine artery.
According to Terminologia Anatomica, the descending palatine artery branches into the greater palatine artery and lesser palatine arteries.
See also
Ascending palatine artery
Additional images
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https://en.wikipedia.org/wiki/Incisive%20foramen
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In the human mouth, the incisive foramen (also known as: "anterior palatine foramen", or "nasopalatine foramen") is the opening of the incisive canals on the hard palate immediately behind the incisor teeth. It gives passage to blood vessels and nerves. The incisive foramen is situated within the incisive fossa of the maxilla.
The incisive foramen is used as an anatomical landmark for defining the severity of cleft lip and cleft palate.
The incisive foramen exists in a variety of species.
Structure
The incisive foramen is a funnel-shaped opening in the bone of the oral hard palate representing the inferior termination of the incisive canal. An oral prominence - the incisive papilla - overlies the incisive fossa.
The incisive foramen is situated immediately behind the incisor teeth, and in between the two premaxillae.
Contents
The incisive foramen allows for blood vessels and nerves to pass. These include:
the pterygopalatine nerves to the hard palate.
the nasopalatine nerves from the floor of the nasal cavity.
the sopalatine branches of the infratrochlear nerve, a branch of the ophthalmic nerve (V1), itself a branch of the trigeminal nerve.
the sphenopalatine artery supplying the mucous membrane covering the hard palate of the mouth.
the sphenopalatine vein draining the mucous membrane covering the hard palate of the mouth.
Clinical significance
As many nerves exit the incisive canal at the incisive foramen, it may be used for injection of local anaesthetic.
When plain radiographs are taken of the mouth, the incisive foramen may be mistaken for a periapical lesion.
The incisive foramen can be used as a landmark when describing cleft lip and cleft palate, which can either extend in front of (primary) or behind (secondary) the foramen. It is also important as a surgical landmark to avoid damaging its nerves and vascular structures.
History
The incisive foramen is also known as the anterior palatine foramen, the nasopalatine foramen, and the incisive
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https://en.wikipedia.org/wiki/Sphenopalatine%20foramen
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The sphenopalatine foramen is a fissure of the skull that connects the nasal cavity and the pterygopalatine fossa. It gives passage to the sphenopalatine artery, nasopalatine nerve, and the superior nasal nerve (all passing from the pterygopalatine fossa into the nasal cavity).
Structure
The processes of the superior border of the palatine bone are separated by the sphenopalatine notch, which is converted into the sphenopalatine foramen by the under surface of the body of the sphenoid.
The sphenopalatine foramen is situated posterior to the middle nasal meatus orbital process of palatine bone, anterior to the sphenoidal process of palatine bone, inferior to the body and of the sphenoid bone, and superior to the superior margin of the perpendicular plate of palatine bone.
Relations
The ethmoid crest (a reliable surgical landmark) is situated anterior to the sphenopalatine foramen.
Additional images
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https://en.wikipedia.org/wiki/Sphenopalatine%20artery
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The sphenopalatine artery (nasopalatine artery) is an artery of the head, commonly known as the artery of epistaxis. It passes through the sphenopalatine foramen to reach the nasal cavity. It is the main artery of the nasal cavity.
Course
The sphenopalatine artery is a branch of the maxillary artery which passes through the sphenopalatine foramen into the cavity of the nose, at the back part of the superior meatus. Here it gives off its posterior lateral nasal branches.
Crossing the under surface of the sphenoid, the sphenopalatine artery ends on the nasal septum as the posterior septal branches. Here it will anastomose with the branches of the greater palatine artery.
Clinical significance
The sphenopalatine artery is the artery responsible for the most serious, posterior nosebleeds (also known as epistaxis). It can be ligated surgically or blocked under image guidance with minimally invasive techniques by interventional radiologist using tiny microparticles to control such nosebleeds.
See also
Kiesselbach's plexus
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https://en.wikipedia.org/wiki/Covox
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SRT, Inc., doing business as Covox, Inc., was a small, privately owned American technology company active from 1975 to 1994. The company released a number of sound-generating devices for microcomputers and personal computers from the 1980s to the 1990s. They are perhaps best known for the Speech Thing, a digital-to-analog converter that plugs into a parallel port of the IBM Personal Computer. Covox was originally based in Southern California but moved their headquarters to Eugene, Oregon, in the early 1980s.
History
SRT, Inc., was founded by Larry Stewart in Southern California in 1975. Stewart had previously worked in the aerospace industry into the 1960s, where he got the idea for Av-Alarm, a sound-generating device intended to scare off birds from outside locations such as vegetable crops and vineyards. SRT relocated to Eugene, Oregon, in 1982, Stewart finding Oregon to be a cheaper state in which to conduct his business. Around this time, he hired his sons Mike Stewart and Brad Stewart to manage the company. Together they established Covox, Inc., a subsidiary of SRT, in 1982; this subsidiary was dedicated to audio products for microcomputers and personal computers and soon after subsumed the SRT name. Brad Stewart, named the company's vice president, was responsible for the development all of Covox's products. Covox's first product was released in 1984; called the Voice Master, it was a low-cost speech-synthesis board for the Commodore 64, intended for business and education. A successor to this device, the Voice Master II, was released in 1990. By mid-1987, sales of Covox products represented 85 percent of SRT's total sales.
In late 1987, Covox released the Speech Thing, a simple digital-to-analog converter that plugs into a parallel port of the IBM Personal Computer (and compatibles). It was the first sound device for the IBM PC capable of playing digital audio samples. The Speech Thing initially sold poorly but later found widespread adoption among video ga
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https://en.wikipedia.org/wiki/INAH%203
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INAH-3 is the short form for the third interstitial nucleus of the anterior hypothalamus, and is the sexually dimorphic nucleus of humans. The INAH-3 is significantly larger in males than in females regardless of age and larger in heterosexual males than in homosexual males and heterosexual females.
Research
The term INAH (interstitial nuclei of the anterior hypothalamus), first proposed in 1989 by a group of the University of California at Los Angeles, refers to 4 previously undescribed cell groups of the preoptic-anterior hypothalamic area (PO-AHA) of the human brain, which is a structure that influences gonadotropin secretion, maternal behavior, and sexual behavior in several mammalian species. There are four nuclei in the PO-AHA (INAH1-4). One of these nuclei, INAH-3, was found to be 2.8 times larger in the male brain than in the female brain regardless of age.
A study authored by Simon LeVay and published in the journal Science suggests that the region is an important biological substrate with regard to sexual orientation. This article reported the INAH-3 to be smaller on average in homosexual men than in heterosexual men, and in fact has approximately the same size in homosexual men as in heterosexual women. Further research has found that the INAH3 is smaller in volume in homosexual men than in heterosexual men because homosexual men have a higher neuronal packing density (the
number of neurons per cubic millimeter) in the INAH3 than heterosexual men; there is no difference in the number or cross-sectional area of neurons in the INAH3 of homosexual versus heterosexual men. It has also been found that there is no effect of HIV infection on the size of INAH3, that is, HIV infection cannot account for the observed difference in INAH3 volume between homosexual and heterosexual men.
LeVay noted three possibilities that could account for his findings: 1. The structural differences in INAH3 between homosexual and heterosexual males were present prenatally or in e
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https://en.wikipedia.org/wiki/Six%20degrees%20of%20freedom
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Six degrees of freedom (6DOF) refers to the six mechanical degrees of freedom of movement of a rigid body in three-dimensional space. Specifically, the body is free to change position as forward/backward (surge), up/down (heave), left/right (sway) translation in three perpendicular axes, combined with changes in orientation through rotation about three perpendicular axes, often termed yaw (normal axis), pitch (transverse axis), and roll (longitudinal axis).
Three degrees of freedom (3DOF), a term often used in the context of virtual reality, typically refers to tracking of rotational motion only: pitch, yaw, and roll.
Robotics
Serial and parallel manipulator systems are generally designed to position an end-effector with six degrees of freedom, consisting of three in translation and three in orientation. This provides a direct relationship between actuator positions and the configuration of the manipulator defined by its forward and inverse kinematics.
Robot arms are described by their degrees of freedom. This is a practical metric, in contrast to the abstract definition of degrees of freedom which measures the aggregate positioning capability of a system.
In 2007, Dean Kamen, inventor of the Segway, unveiled a prototype robotic arm with 14 degrees of freedom for DARPA. Humanoid robots typically have 30 or more degrees of freedom, with six degrees of freedom per arm, five or six in each leg, and several more in torso and neck.
Engineering
The term is important in mechanical systems, especially biomechanical systems, for analyzing and measuring properties of these types of systems that need to account for all six degrees of freedom. Measurement of the six degrees of freedom is accomplished today through both AC and DC magnetic or electromagnetic fields in sensors that transmit positional and angular data to a processing unit. The data is made relevant through software that integrates the data based on the needs and programming of the users.
The six degrees of
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https://en.wikipedia.org/wiki/Greater%20palatine%20foramen
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At either posterior angle of the hard palate is the greater palatine foramen, for the transmission of the descending palatine vessels and greater palatine nerve; and running anteriorly (forward) and medially (towards the center-line) from it is a groove, for the same vessels and nerve.
Variations
The greater palatine foramen (GPF) is related to the upper 3rd molar tooth in most of the skulls (55%), 2nd molar in (12%), between the 2nd and 3rd molar in (19%) and retromolar in (14%). The shape of the foramen is elongated antero-posteriorly; however, an unusually crescent shaped foramen is rare.
See also
Greater palatine canal
Lesser palatine foramina
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https://en.wikipedia.org/wiki/Lesser%20palatine%20foramina
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Behind the greater palatine foramen is the pyramidal process of the palatine bone, perforated by one or more lesser palatine foramina which carry the lesser palatine nerve, and marked by the commencement of a transverse ridge, for the attachment of the tendinous expansion of the tensor veli palatini.
See also
Greater palatine foramen
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https://en.wikipedia.org/wiki/Glossoepiglottic%20folds
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The anterior or lingual surface of the epiglottis is curved forward, and covered on its upper, free part by mucous membrane which is reflected on to the sides and root of the tongue, forming a median and two lateral glossoepiglottic folds; the lateral folds are partly attached to the wall of the pharynx.
Additional Images
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https://en.wikipedia.org/wiki/Sylvester%27s%20sequence
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In number theory, Sylvester's sequence is an integer sequence in which each term is the product of the previous terms, plus one. The first few terms of the sequence are
2, 3, 7, 43, 1807, 3263443, 10650056950807, 113423713055421844361000443 .
Sylvester's sequence is named after James Joseph Sylvester, who first investigated it in 1880. Its values grow doubly exponentially, and the sum of its reciprocals forms a series of unit fractions that converges to 1 more rapidly than any other series of unit fractions. The recurrence by which it is defined allows the numbers in the sequence to be factored more easily than other numbers of the same magnitude, but, due to the rapid growth of the sequence, complete prime factorizations are known only for a few of its terms. Values derived from this sequence have also been used to construct finite Egyptian fraction representations of 1, Sasakian Einstein manifolds, and hard instances for online algorithms.
Formal definitions
Formally, Sylvester's sequence can be defined by the formula
The product of the empty set is 1, so s0 = 2.
Alternatively, one may define the sequence by the recurrence
with s0 = 2.
It is straightforward to show by induction that this is equivalent to the other definition.
Closed form formula and asymptotics
The Sylvester numbers grow doubly exponentially as a function of n. Specifically, it can be shown that
for a number E that is approximately 1.26408473530530... . This formula has the effect of the following algorithm:
s0 is the nearest integer to E 2; s1 is the nearest integer to E 4; s2 is the nearest integer to E 8; for sn, take E 2, square it n more times, and take the nearest integer.
This would only be a practical algorithm if we had a better way of calculating E to the requisite number of places than calculating sn and taking its repeated square root.
The double-exponential growth of the Sylvester sequence is unsurprising if one compares it to the sequence of Fer
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https://en.wikipedia.org/wiki/ECATT
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eCATT (extended Computer Aided Test Tool) is a tool for software test automation developed by SAP. eCATT offers a graphical user interface with ABAP script editor and its own command syntax. The capability for recording and for parameterizing the test components is also present.
External links
Another blog for SAP eCATT tool
eCATT Community on Orkut
eCATT Tutorial
Software testing tools
SAP SE
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https://en.wikipedia.org/wiki/Klavarskribo
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Klavarskribo (sometimes shortened to klavar) is a music notation system that was introduced in 1931 by the Dutchman . The name means "keyboard writing" in Esperanto. It differs from conventional music notation in a number of ways and is intended to be easily readable.
History
Cornelis Pot came from a family of shipbuilders and was managing director of Smit Slikkerveer, a factory which made dynamos for ships. He had also a passion for music and wanted to others to be able to enjoy music by playing and by singing. He studied alternative music notations and from them developed his idea of Klavarskribo. He expected the music world to embrace his invention but was disappointed when that proved not to be the case. Having the financial means, Pot was able by himself to start and publish written courses and have music transcribed.
In the 1930s the number of klavar users grew enormously and much sheet music was transcribed and published in the klavar notation. During World War II these activities stopped, but afterwards Pot started with a new élan. His Klavarskribo Institute expanded so much as to employ fifty people at one time. Courses in English, French and German were offered.
The Klavarskribo Foundation was established after Pot’s death in 1977 in Ridderkerk (near Rotterdam) with limited financial means. The foundation is concerned with transcribing and publishing music mainly for church organists, an important supportive group. Also written courses for a number of instruments, including guitar, accordion, recorder and in particular piano, and other keyboard instruments, are available. There are more than 10,000 klavar notation users in the Netherlands and abroad.
Notation
The klavar notation distinguishes itself from conventional notation in several ways.
The stave on which the notes are written is vertical so the music is read from top to bottom. Each note has its own individual position, low notes on the left and high notes on the right as on the piano. This s
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https://en.wikipedia.org/wiki/Carbon%20sequestration
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Carbon sequestration (or carbon storage) is the process of storing carbon in a carbon pool. Carbon sequestration is a naturally occurring process but it can also be enhanced or achieved with technology, for example within carbon capture and storage projects. There are two main types of carbon sequestration: geologic and biologic (also called biosequestration).
Carbon dioxide () is naturally captured from the atmosphere through biological, chemical, and physical processes. These changes can be accelerated through changes in land use and agricultural practices, such as converting crop land into land for non-crop fast growing plants. Artificial processes have been devised to produce similar effects, including large-scale, artificial capture and sequestration of industrially produced using subsurface saline aquifers or aging oil fields. Other technologies that work with carbon sequestration include bio-energy with carbon capture and storage, biochar, enhanced weathering, direct air carbon capture and sequestration (DACCS).
Forests, kelp beds, and other forms of plant life absorb carbon dioxide from the air as they grow, and bind it into biomass. However, these biological stores are considered volatile carbon sinks as the long-term sequestration cannot be guaranteed. For example, natural events, such as wildfires or disease, economic pressures and changing political priorities can result in the sequestered carbon being released back into the atmosphere. Carbon dioxide that has been removed from the atmosphere can also be stored in the Earth's crust by injecting it into the subsurface, or in the form of insoluble carbonate salts (mineral sequestration). These methods are considered non-volatile because they remove carbon from the atmosphere and sequester it indefinitely and presumably for a considerable duration (thousands to millions of years).
To enhance carbon sequestration processes in oceans the following technologies have been proposed but none have achieved lar
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https://en.wikipedia.org/wiki/Resident%20monitor
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In computing, a resident monitor is a type of system software program that was used in many early computers from the 1950s to 1970s. It can be considered a precursor to the operating system. The name is derived from a program which is always present in the computer's memory, thus being "resident". Because memory was very limited on those systems, the resident monitor was often little more than a stub that would gain control at the end of a job and load a non-resident portion to perform required job cleanup and setup tasks.
On a general-use computer using punched card input, the resident monitor governed the machine before and after each job control card was executed, loaded and interpreted each control card, and acted as a job sequencer for batch processing operations. The resident monitor could clear memory from the last used program (with the exception of itself), load programs, search for program data and maintain standard input-output routines in memory.
Similar system software layers were typically in use in the early days of the later minicomputers and microcomputers before they gained the power to support full operating systems.
Current use
Resident monitor functionality is present in many embedded systems, boot loaders, and various embedded command lines. The original functions present in all resident monitors are augmented with present-day functions dealing with boot time hardware, disks, ethernet, wireless controllers, etc. Typically, these functions are accessed using a serial terminal or a physical keyboard and display, if attached. Such a resident monitor is frequently called a debugger, boot loader, command-line interface (CLI), etc. The original meaning of serial-accessed or terminal-accessed resident monitor is not frequently used, although the functionality remained the same, and was augmented.
Typical functions of a resident monitor include examining and editing ram and/or ROM (including flash EEPROM) and sometimes special function register
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https://en.wikipedia.org/wiki/Citrinin
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Citrinin is a mycotoxin which is often found in food. It is a secondary metabolite produced by fungi that contaminates long-stored food and it causes different toxic effects, like nephrotoxic, hepatotoxic and cytotoxic effects. Citrinin is mainly found in stored grains, but sometimes also in fruits and other plant products.
History
Citrinin was one of the many mycotoxins discovered by H. Raistrick and A.C. Hetherington in the 1930s. In 1941 H. Raistrick and G. Smith identified citrinin to have a broad antibacterial activity. After this discovery the interest in citrinin rose. However, in 1946 A.M. Ambrose and F. DeEds demonstrated that citrinin was toxic to mammals. As a result, the interest in citrinin decreased, but there still was a lot of research. In 1948 the chemical structure was found by W.B. Whalley and coworkers. Citrinin is a natural compound and it was first isolated from Penicillium citrinum, but is also produced by other Penicillium species, such as the Monascus species and the Aspergillus species, which are both fungi. During the 1950s W.B. Whalley, A.J. Birch and others identified citrinin as a polyketide and investigated its biosynthesis using radioisotopes. During the 1980s and 1990s J. Staunton, U. Sankawa and others also investigated its biosynthesis using stable isotopes and NMR. The gene cluster expression system for citrinin was reported in 2008.
In 1993 the World Health Organisation International Agency for Research on Cancer started to evaluate the carcinogenic potential of mycotoxins. The health hazards of mycotoxins to humans or animals have been reviewed extensively in recent years. To ensure agricultural productivity and sustainability, animal and public health, animal welfare and the environment, maximum levels of undesirable substances in animal feed are laid down in the EU Directive of the European Parliament and the Council of 7 May 2002. While maximum levels for various mycotoxins were set for a number of food and feed products,
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https://en.wikipedia.org/wiki/Elginerpeton
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Elginerpeton is a genus of stegocephalian (stem-tetrapod), the fossils of which were recovered from Scat Craig, Morayshire in the UK, from rocks dating to the late Devonian Period (Late Frasnian stage, 375 million years ago). The type species is Elginerpeton pancheni.
Elginerpeton is known from skeletal fragments including a partial shoulder and hip, a femur, tibia (lower hind limb), and jaw fragments. The holotype is a lower jaw fragment estimated at 40 centimeters in total length. The total body is estimated to have measured about 1.5 m (5 ft) in length. Upon its description, Elginerpeton was allied with Obruchevichthys in the family Elginerpetontidae.
A biomechanical analysis of stegocephalian jaws has indicated that Elginerpeton had an unusual feeding habit among tetrapod relatives. Its jaws were thin, and plotted as the most susceptible to high stresses among the sample group. However, the heavy sculpturing of the bone may have reduced these stresses. It also had a high bite force, third overall compared to Crassigyrinus (second) and Megalocephalus (first). These two features combined indicated that the jaw was best suited for quick, strong bites for hunting small yet fast prey.
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https://en.wikipedia.org/wiki/TSIG
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TSIG (transaction signature) is a computer-networking protocol defined
in RFC 2845. Primarily it enables the Domain Name System (DNS) to authenticate updates to a DNS database. It is most commonly used to update Dynamic DNS or a secondary/slave DNS server. TSIG uses shared secret keys and one-way hashing to provide a cryptographically secure means of authenticating each endpoint of a connection as being allowed to make or respond to a DNS update.
Although queries to DNS may usually be made without authentication, updates to DNS must be authenticated, since they make lasting changes to the structure of the Internet naming system. As the update request may arrive via an insecure channel (the Internet), one must take measures to ensure the authenticity and integrity of the request. The use of a key shared by the client making the update and the DNS server helps to ensure the authenticity and integrity of the update request. A one-way hashing function serves to prevent malicious observers from modifying the update and forwarding on to the destination, thus ensuring integrity of the message from source to destination.
A timestamp is included in the TSIG protocol to prevent recorded responses from being reused, which would allow an attacker to breach the security of TSIG. This places a requirement on dynamic DNS servers and TSIG clients to contain an accurate clock. Since DNS servers are connected to a network, the Network Time Protocol can provide an accurate time source.
DNS updates, like queries, are normally transported via UDP since it requires lower overhead than TCP. However, DNS servers support both UDP and TCP requests.
Implementation
An update, as specified in RFC 2136, is a set of instructions to a DNS server. These include a header, the zone to be updated, the prerequisites that must be satisfied, and the record(s) to be updated. TSIG adds a final record, which includes a timestamp and the hash of the request. It also includes the name of the secr
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https://en.wikipedia.org/wiki/Ptolemy%20Project
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The Ptolemy Project is an ongoing project aimed at modeling, simulating, and designing concurrent, real-time, embedded systems. The focus of the Ptolemy Project is on assembling concurrent components. The principal product of the project is the Ptolemy II model based design and simulation tool. The Ptolemy Project is conducted in the Industrial Cyber-Physical Systems Center (iCyPhy) in the Department of Electrical Engineering and Computer Sciences of the University of California at Berkeley, and is directed by Prof. Edward A. Lee.
The key underlying principle in the project is the use of well-defined models of computation that govern the interaction between components. A major problem area being addressed is the use of heterogeneous mixtures of models of computation.
The project is named after Claudius Ptolemaeus, the 2nd century Greek astronomer, mathematician, and geographer.
The Kepler Project, a community-driven collaboration among researchers at three other University of California campuses has created the Kepler scientific workflow system which is based on Ptolemy II.
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https://en.wikipedia.org/wiki/Milos%20Konopasek
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Milos Konopasek (died in Boston, Massachusetts, 9 January 2002) was a Czechoslovakia-born mechanical engineer best known as the creator of TK!Solver, an iterative, constraint-based declarative environment for the numerical solution of systems of equations.
Biography
Konopasek was born in Czechoslovakia and graduated from the Leningrad Textile Institute, Leningrad, USSR, and received the Ph.D. and D.Sc degrees from the University of Manchester, England. His career included management, research, and teaching positions in Czechoslovakia, United Kingdom, and the United States, including at the Georgia Institute of Technology and North Carolina State University.
At Manchester in the late 1960s and early 1970s, he developed a system called "Question Answering System on mathematical models" (QAS). He expected his system to be used by a broad range of non-computer professionals and non-mathematicians who apply math to their fields.
Konopasek recognized that the new personal computer was an ideal vehicle for bringing his concept to the masses and developed a version of his system for them in 1977. In 1982, Software Arts commercialized TK!Solver based on his work.
Konopasek was Senior Scientist at Software Arts while holding a visiting faculty position in the Department of Mechanical Engineering at M.I.T.; when TK!Solver was sold to Universal Technical Systems (Rockford, Illinois), he continued as Vice President of UTS.
Most of his research interests and contributions were in textile engineering, applied mechanics, operations research, and computer science, in areas as diverse as CAD/CAM, large deflection analysis of slender bodies, topology of line structures,
and language design. Konopasek was a member of the ACM and the IEEE Computer Society.
Notes
Scientific computing researchers
Czech computer scientists
American computer scientists
2002 deaths
Year of birth missing
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https://en.wikipedia.org/wiki/Uniform%20algebra
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In functional analysis, a uniform algebra A on a compact Hausdorff topological space X is a closed (with respect to the uniform norm) subalgebra of the C*-algebra C(X) (the continuous complex-valued functions on X) with the following properties:
the constant functions are contained in A
for every x, y X there is fA with f(x)f(y). This is called separating the points of X.
As a closed subalgebra of the commutative Banach algebra C(X) a uniform algebra is itself a unital commutative Banach algebra (when equipped with the uniform norm). Hence, it is, (by definition) a Banach function algebra.
A uniform algebra A on X is said to be natural if the maximal ideals of A are precisely the ideals of functions vanishing at a point x in X.
Abstract characterization
If A is a unital commutative Banach algebra such that for all a in A, then there is a compact Hausdorff X such that A is isomorphic as a Banach algebra to a uniform algebra on X. This result follows from the spectral radius formula and the Gelfand representation.
Notes
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https://en.wikipedia.org/wiki/Medial%20axis
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The medial axis of an object is the set of all points having more than one closest point on the object's boundary. Originally referred to as the topological skeleton, it was introduced in 1967 by Harry Blum as a tool for biological shape recognition. In mathematics the closure of the medial axis is known as the cut locus.
In 2D, the medial axis of a subset S which is bounded by planar curve C is the locus of the centers of circles that are tangent to curve C in two or more points, where all such circles are contained in S. (It follows that the medial axis itself is contained in S.)
The medial axis of a simple polygon is a tree whose leaves are the vertices of the
polygon, and whose edges are either straight segments or arcs of parabolas.
The medial axis together with the associated radius function of the maximally inscribed discs is called the medial axis transform (MAT). The medial axis transform is a complete shape descriptor (see also shape analysis), meaning that it can be used to reconstruct the shape of the original domain.
The medial axis is a subset of the symmetry set, which is defined similarly, except that it also includes circles not contained in S. (Hence, the symmetry set of S generally extends to infinity, similar to the Voronoi diagram of a point set.)
The medial axis generalizes to k-dimensional hypersurfaces by replacing 2D circles with k-dimension hyperspheres. The 2D medial axis is useful for character and object recognition, while the 3D medial axis has applications in surface reconstruction for physical models, and for dimensional reduction of complex models. In any dimension, the medial axis of a bounded open set is homotopy equivalent to the given set.
If S is given by a unit speed parametrisation , and is the unit tangent vector at each point. Then there will be a bitangent circle with center c and radius r if
For most curves, the symmetry set will form a one-dimensional curve and can contain cusps. The symmetry set has end points
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https://en.wikipedia.org/wiki/Kinesis%20%28biology%29
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Kinesis, like a taxis or tropism, is a movement or activity of a cell or an organism in response to a stimulus (such as gas exposure, light intensity or ambient temperature).
Unlike taxis, the response to the stimulus provided is non-directional. The animal does not move toward or away from the stimulus but moves at either a slow or fast rate depending on its "comfort zone." In this case, a fast movement (non-random) means that the animal is searching for its comfort zone while a slow movement indicates that it has found it.
Types
There are two main types of kineses, both resulting in aggregations. However, the stimulus does not act to attract or repel individuals.
Orthokinesis: in which the speed of movement of the individual is dependent upon the stimulus intensity. For example, the locomotion of the collembola, Orchesella cincta, in relation to water. With increased water saturation in the soil there is an increase in the direction of its movement towards the aimed place.
Klinokinesis: in which the frequency or rate of turning is proportional to stimulus intensity. For example the behaviour of the flatworm (Dendrocoelum lacteum) which turns more frequently in response to increasing light thus ensuring that it spends more time in dark areas.
Basic model of kinesis
The kinesis strategy controlled by the locally and instantly evaluated well-being (fitness) can be described in simple words: Animals stay longer in good conditions and leave bad conditions more quickly. If the well-being is measured by the local reproduction coefficient then the minimal reaction-diffusion model of kinesis can be written as follows:
For each population in the biological community,
where:
is the population density of ith species,
represents the abiotic characteristics of the living conditions (can be multidimensional),
is the reproduction coefficient, which depends on all and on s,
is the equilibrium diffusion coefficient (defined for equilibrium ). The coefficient charac
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https://en.wikipedia.org/wiki/Time%20Stamp%20Counter
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The Time Stamp Counter (TSC) is a 64-bit register present on all x86 processors since the Pentium. It counts the number of CPU cycles since its reset. The instruction RDTSC returns the TSC in EDX:EAX. In x86-64 mode, RDTSC also clears the upper 32 bits of RAX and RDX. Its opcode is 0F 31. Pentium competitors such as the Cyrix 6x86 did not always have a TSC and may consider RDTSC an illegal instruction. Cyrix included a Time Stamp Counter in their MII.
Use
The Time Stamp Counter was once an excellent high-resolution, low-overhead way for a program to get CPU timing information. With the advent of multi-core/hyper-threaded CPUs, systems with multiple CPUs, and hibernating operating systems, the TSC cannot be relied upon to provide accurate results — unless great care is taken to correct the possible flaws: rate of tick and whether all cores (processors) have identical values in their time-keeping registers. There is no promise that the timestamp counters of multiple CPUs on a single motherboard will be synchronized. Therefore, a program can get reliable results only by limiting itself to run on one specific CPU. Even then, the CPU speed may change because of power-saving measures taken by the OS or BIOS, or the system may be hibernated and later resumed, resetting the TSC. In those latter cases, to stay relevant, the program must re-calibrate the counter periodically.
Relying on the TSC also reduces portability, as other processors may not have a similar feature. Recent Intel processors include a constant rate TSC (identified by the kern.timecounter.invariant_tsc sysctl on FreeBSD or by the "constant_tsc" flag in Linux's /proc/cpuinfo). With these processors, the TSC ticks at the processor's nominal frequency, regardless of the actual CPU clock frequency due to turbo or power saving states. Hence TSC ticks are counting the passage of time, not the number of CPU clock cycles elapsed.
On Windows platforms, Microsoft strongly discourages using the TSC for high-resolu
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https://en.wikipedia.org/wiki/Radial%20distribution%20function
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In statistical mechanics, the radial distribution function, (or pair correlation function) in a system of particles (atoms, molecules, colloids, etc.), describes how density varies as a function of distance from a reference particle.
If a given particle is taken to be at the origin O, and if is the average number density of particles, then the local time-averaged density at a distance from O is . This simplified definition holds for a homogeneous and isotropic system. A more general case will be considered below.
In simplest terms it is a measure of the probability of finding a particle at a distance of away from a given reference particle, relative to that for an ideal gas. The general algorithm involves determining how many particles are within a distance of and away from a particle. This general theme is depicted to the right, where the red particle is our reference particle, and blue particles are those whose centers are within the circular shell, dotted in orange.
The radial distribution function is usually determined by calculating the distance between all particle pairs and binning them into a histogram. The histogram is then normalized with respect to an ideal gas, where particle histograms are completely uncorrelated. For three dimensions, this normalization is the number density of the system multiplied by the volume of the spherical shell, which symbolically can be expressed as .
Given a potential energy function, the radial distribution function can be computed either via computer simulation methods like the Monte Carlo method, or via the Ornstein-Zernike equation, using approximative closure relations like the Percus-Yevick approximation or the Hypernetted Chain Theory. It can also be determined experimentally, by radiation scattering techniques or by direct visualization for large enough (micrometer-sized) particles via traditional or confocal microscopy.
The radial distribution function is of fundamental importance since it can be used, u
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https://en.wikipedia.org/wiki/Underactuation
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Underactuation is a technical term used in robotics and control theory to describe mechanical systems that cannot be commanded to follow arbitrary trajectories in configuration space. This condition can occur for a number of reasons, the simplest of which is when the system has a lower number of actuators than degrees of freedom. In this case, the system is said to be trivially underactuated.
The class of underactuated mechanical systems is very rich and includes such diverse members as automobiles, airplanes, and even animals.
Definition
To understand the mathematical conditions which lead to underactuation, one must examine the dynamics that govern the systems in question. Newton's laws of motion dictate that the dynamics of mechanical systems are inherently second order. In general, these dynamics can be described by a second order differential equation:
Where:
is the position state vector is the vector of control inputs is time.
Furthermore, in many cases the dynamics for these systems can be rewritten to be affine in the control inputs:
When expressed in this form, the system is said to be underactuated if:
When this condition is met, there are acceleration directions that can not be produced no matter what the control vector is.
Note that does not explicitly represent the number of actuators present in the system. Indeed, there may be more actuators than degrees of freedom and the system may still be underactuated. Also worth noting is the dependence of on the state . That is, there may exist states in which an otherwise fully actuated system becomes underactuated.
Examples
The classic inverted pendulum is an example of a trivially underactuated system: it has two degrees of freedom (one for its support's motion in the horizontal plane, and one for the angular motion of the pendulum), but only one of them (the cart position) is actuated, and the other is only indirectly controlled. Although naturally extremely unstable, this underactua
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https://en.wikipedia.org/wiki/Telephone%20prefix
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A telephone prefix is the first set of digits after the country, and area codes of a telephone number; in the North American Numbering Plan countries (country code 1), it is the first three digits of a seven-digit local phone number, the second three digits of the 3-3-4 scheme. In other countries both the prefix and the number may have different lengths. It shows which exchange the remaining numbers refer to. A full telephone number is usually made up of a country code (required for international calls only), area code (required for calls between telephone areas), prefix, and subscriber number.
Some places restrict certain prefixes to fax numbers or cell phones only; in other places such dedicated prefixes are not used.
As telephone technology advanced, the precise significance of the prefix became blurred in many places; for instance, 485 in London, UK, was once the GULliver exchange, but now 44-20-7485-xxxx is just considered one of many number blocks served by the CLKEN Kentish Town exchange.
History
In the earliest days of telephony an operator at the exchange connected calls to a named subscriber; later, numbers were allocated to each subscriber on an exchange, but users on different exchanges could not speak to each other. As progress was made, exchanges were connected together, initially connected by the operator by name, and later dialed by users with prefixes such as WHI (for the WHItehall exchange, hence the famous Whitehall 1212 number for Scotland Yard), with letters corresponding to numbers on the dial (WHI was equivalent to # 944), later replaced by the numerical prefixes which remain in use.
United States prefixes
In most but not all U.S. telephone areas, the prefix 555 is reserved for special services. In particular, 555-1212 is telephone information in most areas. When telephone numbers are used in television programs and movies, a significant number of viewers dial them. Numbers prefixed 555 are usually used for such fictitious use, as they ar
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https://en.wikipedia.org/wiki/KOZL-TV
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KOZL-TV (channel 27) is a television station in Springfield, Missouri, United States, affiliated with MyNetworkTV. It is owned by Nexstar Media Group alongside Osage Beach–licensed Fox affiliate KRBK (channel 49); Nexstar also provides certain services to CBS affiliate KOLR (channel 10) under a local marketing agreement (LMA) with Mission Broadcasting. The stations share studios on East Division Street in Springfield, while KOZL-TV's transmitter is located on Switchgrass Road, north of Fordland.
History
Early history
The station first signed on the air in 1968 as KMTC; founded by Meyer Communications, it originally operated as the market's first full-time ABC affiliate. It originally operated from studios located on East Cherry Street in Springfield. Prior to its sign-on, ABC programming had been limited to off-hours clearances on KYTV (channel 3) and KTTS-TV (channel 10, now KOLR) from their respective sign-ons in October and March 1953. Although the Springfield market had had a large enough population to support three full-time network affiliates since the 1950s, prospective station owners were skeptical about launching a UHF station in a market that stretched across a large and mostly mountainous swath of Missouri and Arkansas. UHF stations have never gotten very good reception across large areas or rugged terrain. In 1980, the station adopted the on-air brand "C-27". In 1985, the station was purchased by Woods Communications; after the sale was finalized, channel 27 changed its call letters to KDEB-TV (named after Deborah Woods, the daughter of the president of Woods Communications).
As a Fox affiliate
In January 1985, KMTC renewed its ABC affiliation. The following month, TV syndicator Telepictures, who had recently purchased cross-town independent KSPR (channel 33), attempted to persuade ABC to make an affiliation agreement via a presentation to the network. ABC then convinced KMTC to develop their own presentation for the network that would defend the sta
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https://en.wikipedia.org/wiki/Pim%20weight
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Pim weights were polished stones about 15 mm (5/8 inch) diameter, equal to about two-thirds of a Hebrew shekel. Many specimens have been found since their initial discovery early in the 20th century, and each one weighs about 7.6 grams, compared to 11.5 grams of a shekel. Its name comes from the inscription seen across the top of its dome shape: the Phoenician letters 𐤐𐤉𐤌 (Hebrew , transliterated pym).
Impact
Prior to the discovery of the weights by archaeologists, scholars did not know how to translate the word (pîm) in 1 Samuel 13:21. Robert Alexander Stewart Macalister's excavations at Gezer (1902-1905 and 1907-1909) were published in 1912 with an illustration showing one such weight, which Macalister compared to another published in 1907 by Charles Simon Clermont-Ganneau.
Here is the 1611 translation of the King James Version of the Bible:
Yet they had a file for the mattocks, and for the coulters, and for the forks, and for the axes, and to sharpen the goads.
The 1982 New King James Version rendered it:
And the charge for a sharpening was a pim for the plowshares, the mattocks, the forks, and the axes, and to set the points of the goads.
Photos
See also
Ancient Hebrew units of measurement
Biblical archaeology
List of artifacts significant to the Bible
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https://en.wikipedia.org/wiki/Virtual%20appliance
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A virtual appliance is a pre-configured virtual machine image, ready to run on a hypervisor; virtual appliances are a subset of the broader class of software appliances. Installation of a software appliance on a virtual machine and packaging that into an image creates a virtual appliance. Like software appliances, virtual appliances are intended to eliminate the installation, configuration and maintenance costs associated with running complex stacks of software.
A virtual appliance is not a complete virtual machine platform, but rather a software image containing a software stack designed to run on a virtual machine platform which may be a Type 1 or Type 2 hypervisor
. Like a physical computer, a hypervisor is merely a platform for running an operating system environment and does not provide application software itself.
Many virtual appliances provide a Web page user interface to permit their configuration. A virtual appliance is usually built to host a single application; it therefore represents a new way to deploy applications on a network.
File formats
Virtual appliances are provided to the user or customer as files, via either electronic downloads or physical distribution. The file format most commonly used is the Open Virtualization Format (OVF). It may also be distributed as Open Virtual Appliance (OVA), the .ova file format is interchangeable with .ovf. The Distributed Management Task Force (DMTF) publishes the OVF specification documentation. Most virtualization platforms, including those from VMware, Microsoft, Oracle, and Citrix, can install virtual appliances from an OVF file.
Grid computing
Virtualization solves a key problem in the grid computing arena – namely, the reality that any sufficiently large grid will inevitably consist of a wide variety of heterogeneous hardware and operating system configurations. Adding virtual appliances into the picture allows for extremely rapid provisioning of grid nodes and importantly, cleanly decouples the grid
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https://en.wikipedia.org/wiki/BSD%20Authentication
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BSD Authentication, otherwise known as BSD Auth, is an authentication framework and software API employed by OpenBSD and accompanying software such as OpenSSH. It originated with BSD/OS, and although the specification and implementation were donated to the FreeBSD project by BSDi, OpenBSD chose to adopt the framework in release 2.9. Pluggable Authentication Modules (PAM) serves a similar purpose on other operating systems such as Linux, FreeBSD and NetBSD.
BSD Auth performs authentication by executing scripts or programs as separate processes from the one requiring the authentication. This prevents the child authentication process from interfering with the parent except through a narrowly defined inter-process communication API, a technique inspired by the principle of least privilege and known as privilege separation. This behaviour has significant security benefits, notably improved fail-safeness of software, and robustness against malicious and accidental software bugs.
See also
Name Service Switch
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https://en.wikipedia.org/wiki/Aluminium%20silicate
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Aluminium silicate (or aluminum silicate) is a name commonly applied to chemical compounds which are derived from aluminium oxide, Al2O3 and silicon dioxide, SiO2 which may be anhydrous or hydrated, naturally occurring as minerals or synthetic. Their chemical formulae are often expressed as xAl2O3·ySiO2·zH2O. It is known as E number E559.
Main representatives
Andalusite, kyanite, and sillimanite are the principal aluminium silicate minerals. The triple point of the three polymorphs is located at a temperature of and a pressure of . These three minerals are commonly used as index minerals in metamorphic rocks.
Al2SiO5, (Al2O3·SiO2), which occurs naturally as the minerals andalusite, kyanite and sillimanite which have distinct crystal structures.
Al2Si2O7, (Al2O3·2SiO2), called metakaolinite, formed from kaolin by heating at .
Al6Si2O13, (3Al2O3·2SiO2), the mineral mullite, the only thermodynamically stable intermediate phase in the Al2O3-SiO2 system at atmospheric pressure. This also called '3:2 mullite' to distinguish it from 2Al2O3·SiO2, Al4SiO8 '2:1 mullite'.
2Al2O3·SiO2, Al4SiO8 '2:1 mullite'.
The above list mentions ternary materials (Si-Al-O). Kaolinite is a quaternary material (Si-Al-O-H). Also called aluminium silicate dihydrate, kaolinite occurs naturally as a mineral. Its formula is Al2Si2O5(OH)4, (Al2O3·2SiO2·2H2O).
Aluminium silicate composite materials, fibres
Aluminium silicate is a type of fibrous material made of aluminium oxide and silicon dioxide, (such materials are also called aluminosilicate fibres). These are glassy solid solutions rather than chemical compounds. The compositions are often described in terms of % weight of alumina, Al2O3 and silica, SiO2. Temperature resistance increases as the % alumina increases. These fibrous materials can be encountered as loose wool, blanket, felt, paper or boards.
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https://en.wikipedia.org/wiki/California%20State%20Summer%20School%20for%20Mathematics%20and%20Science
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The California State Summer School for Mathematics and Science (COSMOS) is a summer program for high school students in California for the purpose of preparing them for careers in mathematics and sciences. It is often abbreviated COSMOS, although COSMOS does not contain the correct letters to create an accurate abbreviation. The program is hosted on four different campuses of the University of California, at Davis, Irvine, San Diego, and Santa Cruz.
History
COSMOS was established by the California State Legislature in the summer of 2000 to stimulate the interests of and provide opportunities for talented California high school students. The California State Summer School for Mathematics & Science is modeled after the California State Summer School for the Arts. In the first summer, 292 students enrolled in the program. Each COSMOS campus only holds 150 students, so selection is competitive. It is a great experience in exploring the sciences and a good activity for college applications, especially the University of California application. This program is designed for extremely gifted students who make amazing discoveries in STEM (Science, Technology, Engineering, Mathematics) areas.
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https://en.wikipedia.org/wiki/Chief%20complaint
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The chief complaint, formally known as CC in the medical field, or termed presenting complaint (PC) in Europe and Canada, forms the second step of medical history taking. It is sometimes also referred to as reason for encounter (RFE), presenting problem, problem on admission or reason for presenting. The chief complaint is a concise statement describing the symptom, problem, condition, diagnosis, physician-recommended return, or other reason for a medical
encounter. In some instances, the nature of a patient's chief complaint may determine if services are covered by health insurance.
When obtaining the chief complaint, medical students are advised to use open-ended questions. Once the presenting problem is elucidated, a history of present illness can be done using acronyms such as SOCRATES or OPQRST to further analyze the severity, onset and nature of the presenting problem. The patient's initial comments to a physician, nurse, or other health care professionals are important for formulating differential diagnoses.
Prevalence
The collection of chief complaint data may be useful in addressing public health issues. Certain complaints are more common in certain settings and among certain populations. Fatigue has been reported as one of the ten most common reasons for seeing a physician. In acute care settings, such as emergency rooms, reports of chest pain are among the most common chief complaints. The most common complaint in ERs has been reported to be abdominal pain. Among nursing home residents seeking treatment at ERs, respiratory symptoms, altered mental status, gastrointestinal symptoms, and falls are the most commonly reported.
See also
Identified patient
Medical history
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https://en.wikipedia.org/wiki/Monte%20Carlo%20molecular%20modeling
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Monte Carlo molecular modelling is the application of Monte Carlo methods to molecular problems. These problems can also be modelled by the molecular dynamics method. The difference is that this approach relies on equilibrium statistical mechanics rather than molecular dynamics. Instead of trying to reproduce the dynamics of a system, it generates states according to appropriate Boltzmann distribution. Thus, it is the application of the Metropolis Monte Carlo simulation to molecular systems. It is therefore also a particular subset of the more
general Monte Carlo method in statistical physics.
It employs a Markov chain procedure in order to determine a new state for a system from a previous one. According to its stochastic nature, this new state is accepted at random. Each trial usually counts as
a move. The avoidance of dynamics restricts the method to studies of static quantities only, but the freedom to choose moves makes the method very flexible. These moves must only satisfy a basic condition of
balance in order for the equilibrium to be properly described, but detailed balance, a stronger condition,
is usually imposed when designing new algorithms. An additional advantage is that some systems, such as the Ising model, lack a dynamical description and are only defined by an energy prescription; for these the Monte Carlo approach is the only one feasible.
The great success of this method in statistical mechanics has led to various generalizations such as the method of simulated annealing for optimization, in which a fictitious temperature is introduced and then gradually lowered.
A range of software packages have been developed specifically for the use of the Metropolis Monte Carlo method on molecular simulations. These include:
BOSS
CP2K
MCPro
Sire
ProtoMS
Faunus
See also
Quantum Monte Carlo
Monte Carlo method in statistical physics
List of software for Monte Carlo molecular modeling
Software for molecular mechanics modeling
Bond fluctuation mode
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https://en.wikipedia.org/wiki/Alexander%20Gelfond
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Alexander Osipovich Gelfond (; 24 October 1906 – 7 November 1968) was a Soviet mathematician. Gelfond's theorem, also known as the Gelfond-Schneider theorem is named after him.
Biography
Alexander Gelfond was born in Saint Petersburg, Russian Empire, the son of a professional physician and amateur philosopher Osip Gelfond. He entered Moscow State University in 1924, started his postgraduate studies there in 1927, and obtained his Ph.D. in 1930. His advisors were Aleksandr Khinchin and Vyacheslav Stepanov.
In 1930, he stayed for five months in Germany (in Berlin and Göttingen) where he worked with Edmund Landau, Carl Ludwig Siegel , and David Hilbert. In 1931 he started teaching as a Professor at the Moscow State University and worked there until the last day of his life. Since 1933 he also worked at the Steklov Institute of Mathematics.
In 1939, he was elected a Corresponding member of the Academy of Sciences of the Soviet Union for his works in the field of Cryptography. According to Vladimir Arnold, during World War II Gelfond was the Chief Cryptographer of the Soviet Navy.
Results
Gelfond obtained important results in several mathematical domains including number theory, analytic functions, integral equations , and the history of mathematics, but his most famous result is his eponymous theorem:
If and are algebraic numbers (with and ), and if is not a real rational number, then any value of is a transcendental number.
This is the famous 7th Hilbert's problem. Gelfond proved a special case of the theorem in 1929 when he was a postgraduate student and fully proved it in 1934. The same theorem was independently proven by Theodor Schneider, and so the theorem is often known as the Gelfond–Schneider theorem. In 1929 Gelfond proposed an extension of the theorem known as Gelfond's conjecture that was proven by Alan Baker in 1966.
Before Gelfond's works only a few numbers such as and were known to be transcendental. After his works, an infinite number of t
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https://en.wikipedia.org/wiki/Organoid
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An organoid is a miniaturized and simplified version of an organ produced in vitro in three dimensions that mimics the key functional, structural and biological complexity of that organ. They are derived from one or a few cells from a tissue, embryonic stem cells or induced pluripotent stem cells, which can self-organize in three-dimensional culture owing to their self-renewal and differentiation capacities. The technique for growing organoids has rapidly improved since the early 2010s, and The Scientist names it as one of the biggest scientific advancements of 2013. Scientists and engineers use organoids to study development and diseases in the laboratory and industry for drug discovery and development, personalized diagnostics and medicine, gene and cell therapies, tissue engineering and regenerative medicine.
History
Attempts to create organs in vitro started with one of the first dissociation-reaggregation experiments where Henry Van Peters Wilson demonstrated that mechanically dissociated sponge cells can reaggregate and self-organize to generate a whole organism. In the subsequent decades, multiple labs were able to generate different types of organs in vitro through the dissociation and reaggregation of organ tissues obtained from amphibians and embryonic chicks. The phenomena of mechanically dissociated cells aggregating and reorganizing to reform the tissue they were obtained from subsequently led to the development of the differential adhesion hypothesis by Malcolm Steinberg. With the advent of the field of stem cell biology, the potential of stem cells to form organs in vitro was realized early on with the observation that when stem cells form teratomas or embryoid bodies, the differentiated cells can organize into different structures resembling those found in multiple tissue types. The advent of the field of organoids, started with a shift from culturing and differentiating stem cells in 2D media, to 3D media to allow for the development of the comple
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https://en.wikipedia.org/wiki/Scoreboarding
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Scoreboarding is a centralized method, first used in the CDC 6600 computer, for dynamically scheduling instructions so that they can execute out of order when there are no conflicts and the hardware is available.
In a scoreboard, the data dependencies of every instruction are logged, tracked and strictly observed at all times. Instructions are released only when the scoreboard determines that there are no conflicts with previously issued ("in flight") instructions. If an instruction is stalled because it is unsafe to issue (or there are insufficient resources), the scoreboard monitors the flow of executing instructions until all dependencies have been resolved before the stalled instruction is issued. In essence: reads proceed on the absence of write hazards, and writes proceed in the absence of read hazards.
Scoreboarding is essentially a hardware implementation of the same underlying algorithm seen in dataflow languages, creating a Directed Acyclic Graph, where the same logic is applied in the programming language runtime.
Stages
Instructions are decoded in order and go through the following four stages.
Issue: The system checks which registers will be read and written by this instruction and where conflicts WAR and RAW and WAW are detected. RAW and WAR hazards are recorded using a Dependency Matrix (constructed from SR NOR latches in the original 6600 design) as it will be needed in the following stages. Simultaneously, an entry is recorded in a second Matrix, which records the instruction order as a Directed Acyclic Graph. In order to avoid output dependencies (WAW – Write after Write) the instruction is stalled until instructions intending to write to the same register are completed. The instruction is also stalled when required functional units are currently busy. No instruction is ever issued unless it is fully trackable from start to finish.
Read operands: After an instruction has been issued and correctly allocated to the required hardware modul
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https://en.wikipedia.org/wiki/Reservation%20station
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A unified reservation station, also known as unified scheduler, is a decentralized feature of the microarchitecture of a CPU that allows for register renaming, and is used by the Tomasulo algorithm for dynamic instruction scheduling.
Reservation stations permit the CPU to fetch and re-use a data value as soon as it has been computed, rather than waiting for it to be stored in a register and re-read. When instructions are issued, they can designate the reservation station from which they want their input to read. When multiple instructions need to write to the same register, all can proceed and only the (logically) last one need actually be written.
It checks if the operands are available (RAW) and if execution unit is free (Structural hazard) before starting execution.
Instructions are stored with available parameters, and executed when ready. Results are identified by the unit that will execute the corresponding instruction.
Implicitly register renaming solves WAR and WAW hazards. Since this is a fully associative structure, it has a very high cost in comparators (need to compare all results returned from processing units with all stored addresses).
In Tomasulo's algorithm, instructions are issued in sequence to Reservation Stations which buffer the instruction as well as the operands of the instruction. If the operand is not available, the Reservation Station listens on a Common Data Bus for the operand to become available. When the operand becomes available, the Reservation Station buffers it, and the execution of the instruction can begin.
Functional Units (such as an adder or a multiplier), each have their own corresponding Reservation Stations. The output of the Functional Unit connects to the Common Data Bus, where Reservation Stations are listening for the operands they need.
Bibliography
Computer Architecture: A Quantitative Approach, John L. Hennessy, David A. Patterson, 2012 () "3.4 Overcoming Data Hazards with Dynamic Scheduling", p 172-180
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https://en.wikipedia.org/wiki/Mosaic%20evolution
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Mosaic evolution (or modular evolution) is the concept, mainly from palaeontology, that evolutionary change takes place in some body parts or systems without simultaneous changes in other parts. Another definition is the "evolution of characters at various rates both within and between species".408 Its place in evolutionary theory comes under long-term trends or macroevolution.
Background
In the neodarwinist theory of evolution, as postulated by Stephen Jay Gould, there is room for differing development, when a life form matures earlier or later, in shape and size. This is due to allomorphism. Organs develop at differing rhythms, as a creature grows and matures. Thus a "heterochronic clock" has three variants: 1) time, as a straight line; 2) general size, as a curved line; 3) shape, as another curved line.
When a creature is advanced in size, it may develop at a smaller rate. Alternatively, it may maintain its original size or, if delayed, it may result in a larger sized creature. That is insufficient to understand heterochronic mechanism.
Size must be combined with shape, so a creature may retain paedomorphic features if advanced in shape or present recapitulatory appearance when retarded in shape. These names are not very indicative, as past theories of development were very confusing.
A creature in its ontogeny may combine heterochronic features in six vectors, although Gould considers that there is some binding with growth and sexual maturation. A creature may, for example, present some neotenic features and retarded development, resulting in new features derived from an original creature only by regulatory genes. Most novel human features (compared to closely related apes) were of this nature, not implying major change in structural genes, as was classically considered.
Taxonomic range
It is not claimed that this pattern is universal, but there is now a wide range of examples from many different taxa, including:
Hominid evolution: the early evolution of
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https://en.wikipedia.org/wiki/Heatwork
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Heatwork is the combined effect of temperature and time. It is important to several industries:
Ceramics
Glass and metal annealing
Metal heat treating
Pyrometric devices can be used to gauge heat work as they deform or contract due to heatwork to produce temperature equivalents. Within tolerances, firing can be undertaken at lower temperatures for a longer period to achieve comparable results. When the amount of heatwork of two firings is the same, the pieces may look identical, but there may be differences not visible, such as mechanical strength and microstructure. Heatwork is taught in material science courses, but is not a precise measurement or a valid scientific concept.
External links
Temperature equivalents table & description of Bullers Rings.
Temperature equivalents table & description of Nimra Cerglass pyrometric cones.
Temperature equivalents table & description of Orton pyrometric cones.
Temperature equivalents table of Seger pyrometric cones.
Temperature Equivalents, °F & °C for Bullers Ring.
Glass physics
Pottery
Metallurgy
Ceramic engineering
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https://en.wikipedia.org/wiki/Selenium%20%28software%29
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Selenium is an open source umbrella project for a range of tools and libraries aimed at supporting browser automation. It provides a playback tool for authoring functional tests across most modern web browsers, without the need to learn a test scripting language (Selenium IDE). It also provides a test domain-specific language (Selenese) to write tests in a number of popular programming languages, including JavaScript (Node.js), C#, Groovy, Java, Perl, PHP, Python, Ruby and Scala. Selenium runs on Windows, Linux, and macOS. It is open-source software released under the Apache License 2.0.
History
Selenium was originally developed by Jason Huggins in 2004 as an internal tool at ThoughtWorks. Huggins was later joined by other programmers and testers at ThoughtWorks, before Paul Hammant joined the team and steered the development of the second mode of operation that would later become "Selenium Remote Control" (RC). The tool was open sourced that year.
In 2005 Dan Fabulich and Nelson Sproul (with help from Pat Lightbody) made an offer to accept a series of patches that would transform Selenium-RC into what it became best known for. In the same meeting, the steering of Selenium as a project would continue as a committee, with Huggins and Hammant being the ThoughtWorks representatives.
In 2007, Huggins joined Google. Together with others like Jennifer Bevan, he continued with the development and stabilization of Selenium RC. At the same time, Simon Stewart at ThoughtWorks developed a superior browser automation tool called WebDriver. In 2009, after a meeting between the developers at the Google Test Automation Conference, it was decided to merge the two projects, and call the new project Selenium WebDriver, or Selenium 2.0.
In 2008, Philippe Hanrigou (then at ThoughtWorks) made "Selenium Grid", which provides a hub allowing the running of multiple Selenium tests concurrently on any number of local or remote systems, thus minimizing test execution time. Grid offered,
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https://en.wikipedia.org/wiki/Metrics%20%28networking%29
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Router metrics are configuration values used by a router to make routing decisions. A metric is typically one of many fields in a routing table. Router metrics help the router choose the best route among multiple feasible routes to a destination. The route will go in the direction of the gateway with the lowest metric.
A router metric is typically based on information such as path length, bandwidth, load, hop count, path cost, delay, maximum transmission unit (MTU), reliability and communications cost.
Examples
A metric can include:
measuring link utilization (using SNMP)
number of hops (hop count)
speed of the path
packet loss (router congestion/conditions)
Network delay
path reliability
path bandwidth
throughput [SNMP - query routers]
load
Maximum transmission unit (MTU)
administrator configured value
In EIGRP, metrics is represented by an integer from 0 to 4,294,967,295 (The size of a 32-bit integer). In Microsoft Windows XP routing it ranges from 1 to 9999.
A metric can be considered as:
additive - the total cost of a path is the sum of the costs of individual links along the path,
concave - the total cost of a path is the minimum of the costs of individual links along the path,
multiplicative - the total cost of a path is the product of the costs of individual links along the path.
Service level metrics
Router metrics are metrics used by a router to make routing decisions. It is typically one of many fields in a routing table.
Router metrics can contain any number of values that help the router determine the best route among multiple routes to a destination. A router metric typically based on information like path length, bandwidth, load, hop count, path cost, delay, MTU, reliability and communications cost.
See also
Administrative distance, indicates the source of routing table entry and is used in preference to metrics for routing decisions
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https://en.wikipedia.org/wiki/Phospholipid%20scramblase
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Scramblase is a protein responsible for the translocation of phospholipids between the two monolayers of a lipid bilayer of a cell membrane. In humans, phospholipid scramblases (PLSCRs) constitute a family of five homologous proteins that are named as hPLSCR1–hPLSCR5. Scramblases are not members of the general family of transmembrane lipid transporters known as flippases. Scramblases are distinct from flippases and floppases. Scramblases, flippases, and floppases are three different types of enzymatic groups of phospholipid transportation enzymes. The inner-leaflet, facing the inside of the cell, contains negatively charged amino-phospholipids and phosphatidylethanolamine. The outer-leaflet, facing the outside environment, contains phosphatidylcholine and sphingomyelin. Scramblase is an enzyme, present in the cell membrane, that can transport (scramble) the negatively charged phospholipids from the inner-leaflet to the outer-leaflet, and vice versa.
Expression
Whereas hPLSCR1, -3, and -4 are expressed in a variety of tissues with few exceptions, expression of hPLSCR2 is restricted only to the testis. hPLSCR4 is not expressed in peripheral blood lymphocytes, whereas hPLSCR1 and -3 were not detected in the brain. However, the functional significance of this differential gene expression is not yet understood. While the gene and the mRNA of hPLSCR5 provide evidence of its existence, the protein has yet to be described in the literature.
Structure
Scramblase proteins contain a region of conservation that possesses a 12-stranded beta barrel surrounding a central alpha helix. This structure shows similarity to the Tubby protein.
Enzyme activation
The enzymatic activity of scramblase depends on the calcium concentration present inside the cell. The calcium concentration inside cells is, under normal conditions, very low; therefore, scramblase has a low activity under resting conditions. Phospholipid redistribution is triggered by increased cytosolic calcium and seems
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https://en.wikipedia.org/wiki/Vena%20comitans
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Vena comitans is Latin for accompanying vein and is also known as a satellite vein. It refers to a vein that is usually paired, with both veins lying on the sides of an artery. They are found in close proximity to arteries so that the pulsations of the artery aid venous return. Because they are generally found in pairs, they are often referred to by their plural form: venae comitantes.
Venae comitantes are usually found with certain smaller arteries, especially those in the extremities. Larger arteries, on the other hand, generally do not have venae comitantes. They usually have a single, similarly sized vein which is not as intimately associated with the artery.
Examples
Examples of arteries and their venae comitantes:
Radial artery and radial veins
Ulnar artery and ulnar veins
Brachial artery and brachial veins
Anterior tibial artery and anterior tibial veins
Posterior tibial artery and posterior tibial veins
Fibular artery and fibular veins
Examples of arteries that do not have venae comitantes (i.e. those that have "regular" veins):
Axillary artery and the axillary vein
Subclavian artery and the subclavian vein
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https://en.wikipedia.org/wiki/Inferior%20ulnar%20collateral%20artery
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The inferior ulnar collateral artery (anastomotica magna artery) is an artery in the arm. It arises about 5 cm. above the elbow from the brachial artery.
Course
It passes medialward upon the Brachialis, and piercing the medial intermuscular septum, winds around the back of the humerus between the Triceps brachii and the bone, forming, by its junction with the profunda brachii, an arch above the olecranon fossa.
Branches and anastomoses
As the vessel lies on the brachialis, it gives off branches which ascend to join the superior ulnar collateral: others descend in front of the medial epicondyle, to anastomose with the anterior ulnar recurrent.
Behind the medial epicondyle a branch anastomoses with the superior ulnar collateral and posterior ulnar recurrent arteries.
Additional images
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https://en.wikipedia.org/wiki/Superior%20ulnar%20collateral%20artery
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The superior ulnar collateral artery (inferior profunda artery), of small size, arises from the brachial artery a little below the middle of the arm; it frequently springs from the upper part of the a. profunda brachii.
It pierces the medial intermuscular septum, and descends on the surface of the medial head of the Triceps brachii to the space between the medial epicondyle and olecranon, accompanied by the ulnar nerve, and ends under the Flexor carpi ulnaris by anastomosing with the posterior ulnar recurrent, and inferior ulnar collateral.
It sometimes sends a branch in front of the medial epicondyle, to anastomose with the anterior ulnar recurrent.
Additional images
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https://en.wikipedia.org/wiki/Deep%20artery%20of%20arm
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The deep artery of arm (also known as deep brachial artery) is a large artery of the arm which arises from the brachial artery. It descends in the arm before ending by anastomosing with the radial recurrent artery.
Structure
Origin
The deep artery of arm arises from the posterolateral aspect of the brachial artery, just below the lower border of the teres major.
Course
It follows closely the radial nerve, running at first backward between the long and medial heads of the triceps brachii, then along the groove for the radial nerve (the radial sulcus), where it is covered by the lateral head of the triceps brachii, to the lateral side of the arm; there it pierces the lateral intermuscular septum, and, descending between the brachioradialis and the brachialis to the front of the lateral epicondyle of the humerus, ends by anastomosing with the radial recurrent artery.
Branches and anastomoses
It gives branches to the deltoid muscle (which, however, primarily is supplied by the posterior circumflex humeral artery) and to the muscles between which it lies; it supplies an occasional nutrient artery which enters the humerus behind the deltoid tuberosity.
A branch ascends between the long and lateral heads of the triceps brachii to anastomose with the posterior humeral circumflex artery; the medial collateral artery, a branch, descends in the middle head of the triceps brachii and assists in forming the anastomosis above the olecranon of the ulna; and, lastly, a radial collateral artery runs down behind the lateral intermuscular septum to the back of the lateral epicondyle of the humerus, where it anastomoses with the interosseous recurrent and the inferior ulnar collateral arteries.
Additional images
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https://en.wikipedia.org/wiki/Radial%20groove
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The radial groove (also known as the musculospiral groove, radial sulcus, or spiral groove) is a broad but shallow oblique depression for the radial nerve and deep brachial artery. It is located on the center of the lateral border of the humerus bone. It is situated alongside the posterior margin of the deltoid tuberosity, ending at its inferior margin.
Although it provides protection to the radial nerve, it is often involved in compressions on the nerve (due to external pressure due to surgery) that can cause radial nerve palsy.
See also
Intertubercular groove
Triceps brachii muscle
Additional images
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https://en.wikipedia.org/wiki/Bicipital%20groove
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The bicipital groove (intertubercular groove, sulcus intertubercularis) is a deep groove on the humerus that separates the greater tubercle from the lesser tubercle. It allows for the long tendon of the biceps brachii muscle to pass.
Structure
The bicipital groove separates the greater tubercle from the lesser tubercle. It is usually around 8 cm long and 1 cm wide in adults. It lodges the long tendon of the biceps brachii muscle between the tendon of the pectoralis major muscle on the lateral lip and the tendon of the teres major muscle on the medial lip. It also transmits a branch of the anterior humeral circumflex artery to the shoulder joint.
The insertion of the latissimus dorsi muscle is found along the floor of the bicipital groove. The teres major muscle inserts on the medial lip of the groove.
It runs obliquely downward, and ends near the junction of the upper with the middle third of the bone. It is the lateral wall of the axilla.
Function
The bicipital groove allows for the long tendon of the biceps brachii muscle to pass.
Gallery
See also
Radial groove
Medial bicipital groove
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https://en.wikipedia.org/wiki/HyperSCSI
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HyperSCSI is an outdated computer network protocol for accessing storage by sending and receiving SCSI commands. It was developed by researchers at the Data Storage Institute in Singapore in 2000 to 2003.
HyperSCSI is unlike iSCSI in that it bypassed the internet protocol suite (TCP/IP) and works directly over Ethernet to form its storage area network (SAN). It skipped the routing, retransmission, segmentation, reassembly, and all the other problems that the TCP/IP suite addresses. Compared to iSCSI, this was meant to give a performance benefit at the cost of IP's flexibility. An independent performance test showed that performance was unstable with network congestion.
Since HyperSCSI was in direct competition with the older and well established Fibre Channel, and the standardized iSCSI, it was not adopted by commercial vendors. Some researchers at Huazhong University of Science and Technology noted the failure to provide any transport layer protocol, so implemented a reliability layer in 2007.
Another version called HS/IP was developed over the Internet Protocol (IP).
See also
Fibre Channel over Ethernet
Fibre Channel over IP
Internet Fibre Channel Protocol
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https://en.wikipedia.org/wiki/Pfsync
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pfsync is a computer protocol used to synchronise firewall states between machines running Packet Filter (PF) for high availability. It is used along with CARP to make sure a backup firewall has the same information as the main firewall. When the main machine in the firewall cluster dies, the backup machine is able to accept current connections without loss.
See also
OpenBSD
PF (firewall)
CARP
Linux-HA
Linux Virtual Server
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https://en.wikipedia.org/wiki/Dyall%20Hamiltonian
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In quantum chemistry, the Dyall Hamiltonian is a modified Hamiltonian with two-electron nature. It can be written as follows:
where labels , , denote core, active and virtual orbitals (see Complete active space) respectively, and are the orbital energies of the involved orbitals, and operators are the spin-traced operators . These operators commute with and , therefore the application of these operators on a spin-pure function produces again a spin-pure function.
The Dyall Hamiltonian behaves like the true Hamiltonian inside the CAS space, having the same eigenvalues and eigenvectors of the true Hamiltonian projected onto the CAS space.
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https://en.wikipedia.org/wiki/Bob%20Colwell
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Robert P. "Bob" Colwell (born 1954) is an electrical engineer who worked at Intel and later served as Director of the Microsystems Technology Office (MTO) at DARPA. He was the chief IA-32 architect on the Pentium Pro, Pentium II, Pentium III, and Pentium 4 microprocessors. Bob retired from Intel in 2000. He was an Intel Fellow from 1995 to 2000.
Early life and education
Colwell grew up in a small blue collar town in Pennsylvania and was born into a family of six children. His father was a milkman for 35 years. He attended the University of Pittsburgh and gained an undergraduate degree in Electrical Engineering. He later attended Carnegie Mellon University to get a PhD in Electrical Engineering.
Career
Colwell worked at a company called Multiflow in the late 1980s as a design engineer.
In 1990 he joined Intel as a senior architect and was involved in the development of the P6 "core". The P6 core was used in the Pentium Pro, Pentium II, and Pentium III microprocessors, and designs derived from it are used in the Pentium M, Core Duo and Core Solo, and Core 2 microprocessors sold by Intel.
Memberships and awards
Colwell earned the ACM Eckert-Mauchly Award in 2005, and wrote the "At Random" column for Computer, a journal published by the IEEE Computer Society.
Publications
Colwell is the author of several papers in addition to the book The Pentium Chronicles: The People, Passion, and Politics Behind Intel's Landmark Chips, . Colwell has spoken at universities on the challenges in chip design and management principles needed to tackle them.
Personal life
Colwell met his wife in college and he married in 1979. He has three children.
External links
List of publications
Internet stream of Stanford Talk, February 18, 2004 (ASF)
Bob Colwell's talk at GCC
Bio page at DARPA MTO
Computer designers
1954 births
Living people
Swanson School of Engineering alumni
Fellows of the American Academy of Arts and Sciences
Members of the United States National Academy of Engin
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https://en.wikipedia.org/wiki/Flower%20induction
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Flower induction is the physiological process in the plant by which the shoot apical meristem becomes competent to develop flowers. Biochemical changes at the apex, particularly those caused by cytokinins, accompany this process. Usually flower induction is followed by flower differentiation, with some notable exceptions such as in kiwifruit, where the two processes are separated. Flower induction can be reversed, but flower differentiation is irreversible, because anatomical changes are in place.
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https://en.wikipedia.org/wiki/Block%20upconverter
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A block upconverter (BUC) is used in the transmission (uplink) of satellite signals. It converts a band of frequencies from a lower frequency to a higher frequency. Modern BUCs convert from the L band to Ku band, C band and Ka band. Older BUCs convert from a 70 MHz intermediate frequency (IF) to Ku band or C band.
Most BUCs use phase-locked loop local oscillators and require an external 10 MHz frequency reference to maintain the correct transmit frequency.
BUCs used in remote locations are often 2 or 4 W in the Ku band and 5 W in the C band. The 10 MHz reference frequency is usually sent on the same feedline as the main carrier. Many smaller BUCs also get their direct current (DC) over the feedline, using an internal DC block.
BUCs are generally used in conjunction with low-noise block converters (LNB). The BUC, being an up-converting device, makes up the "transmit" side of the system, while the LNB is the down-converting device and makes up the "receive" side. An example of a system utilizing both a BUC and an LNB is a VSAT system, used for bidirectional Internet access via satellite.
The block upconverter is a block shaped device assembled with the LNB in association with an OMT, orthogonal mode transducer to the feed-horn that faces the reflector parabolic dish. This is opposed to other types of frequency upconverter which may be rack mounted indoors or not co-located with the dish.
Radio technology
Satellite broadcasting
Telecommunications equipment
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https://en.wikipedia.org/wiki/Flower%20differentiation
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Flower differentiation is a plant process by which the shoot apical meristem changes its anatomy to generate a flower or inflorescence in lieu of other structures. Anatomical changes begin at the edge of the meristem, generating first the outer whorls of the flower - the calyx and the corolla, and later the inner whorls of the flower, the androecium and gynoecium.
Flower differentiation can take from only a few days (in annual plants) to 4–11 months (in fruit crops).
The process is preceded by flower induction.
Morphological Characteristics:[edit]
Flower bud differentiation was seen to have five different stages in the flower M.sinostellata.
Undifferentiated stage: The flower bud was seen as yellow-green, had no scale hairs and was smooth outside. Its differentiation primordium cells are small and arranged closely.
Early flower bud differentiation stage: The bud's basal region begins to expand and develops yellow-brown hairs on its outer surface. The bracts inside the growing bud begin to stratify. Cells are still closely arranged and the floral primordium becomes larger.
Petal primordium differentiation stage: At this stage, the bud becomes more distinct than the leaf primordia by becoming longer and wider. The bud develops a couple of spathe-like bracts with scale hairs. The start of petal primordium differentiation is demonstrated by the wave-like surface of the tip of the developing floral meristem.
Stamen primordium differentiation stage: The bud has expanded and the outer hairs mentioned earlier have become denser. The inner buds differentiation region forms a rounded hump shape with a smooth tip. The bud meristem inner cells are separate from each other while the outer cells stay small and compact. Rows of small spots were found on the inside of the petal primordia around the bottom of the meristem.
Pistil primordium differentiation stage: The pistil primordia beginning to differentiate is indicated by the multiple round bulges in the upper region of
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https://en.wikipedia.org/wiki/Sum-frequency%20generation
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Sum-frequency generation (SFG) is a second order nonlinear optical process based on the mixing of two input photons at frequencies and to generate a third photon at frequency . As with any optical phenomenon in nonlinear optics, this can only occur under conditions where:
the light is interacting with matter, that lacks centrosymmetry (for example, surfaces and interfaces);
the light has a very high intensity (typically from a pulsed laser).
Sum-frequency generation is a "parametric process", meaning that the photons satisfy energy conservation, leaving the matter unchanged:
Second-harmonic generation
A special case of sum-frequency generation is second-harmonic generation, in which . In fact, in experimental physics, this is the most common type of sum-frequency generation. This is because in second-harmonic generation, only one input light beam is required, but if , two simultaneous beams are required, which can be more difficult to arrange. In practice, the term "sum-frequency generation" usually refers to the less common case in which .
Phase-matching
For sum-frequency generation to occur efficiently, phase-matching conditions must be satisfied:
where are the angular wavenumbers of the three waves as they travel through the medium. (Note that the equation resembles the equation for conservation of momentum.) As this condition is satisfied more and more accurately, the sum-frequency generation becomes more and more efficient.
Sum frequency generation spectroscopy
Sum frequency generation spectroscopy uses two laser beams mixed at an interface to generate an output beam with a frequency equal to the sum of the two input frequencies. Sum frequency generation spectroscopy is used to analyze surfaces and interfaces, carrying complementary information to infrared and Raman spectroscopy.
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https://en.wikipedia.org/wiki/Optical%20chaos
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In the field of photonics, optical chaos is chaos generated by laser instabilities using different schemes in semiconductor and fiber lasers. Optical chaos is observed in many non-linear optical systems. One of the most common examples is an optical ring resonators.
Optical computing
Optical chaos was a field of research in the mid-1980s and was aimed at the production of all-optical devices including all-optical computers. Researchers realised later the inherent limitation of the optical systems due to the nonlocalised nature of photons compared to highly localised nature of electrons.
Communications
Research in optical chaos has seen a recent resurgence in the context of studying synchronization phenomena, and in developing techniques for secure optical communications.
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https://en.wikipedia.org/wiki/Gauss%E2%80%93Manin%20connection
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In mathematics, the Gauss–Manin connection is a connection on a certain vector bundle over a base space S of a family of algebraic varieties . The fibers of the vector bundle are the de Rham cohomology groups of the fibers of the family. It was introduced by for curves S and by in higher dimensions.
Flat sections of the bundle are described by differential equations; the best-known of these is the Picard–Fuchs equation, which arises when the family of varieties is taken to be the family of elliptic curves. In intuitive terms, when the family is locally trivial, cohomology classes can be moved from one fiber in the family to nearby fibers, providing the 'flat section' concept in purely topological terms. The existence of the connection is to be inferred from the flat sections.
Intuition
Consider a smooth morphism of schemes over characteristic 0. If we consider these spaces as complex analytic spaces, then the Ehresmann fibration theorem tells us that each fiber is a smooth manifold and each fiber is diffeomorphic. This tells us that the de-Rham cohomology groups are all isomorphic. We can use this observation to ask what happens when we try to differentiate cohomology classes using vector fields from the base space .
Consider a cohomology class such that where is the inclusion map. Then, if we consider the classes
eventually there will be a relation between them, called the Picard–Fuchs equation. The Gauss–Manin connection is a tool which encodes this information into a connection on the flat vector bundle on constructed from the .
Example
A commonly cited example is the Dwork construction of the Picard–Fuchs equation. Let
be the elliptic curve .
Here, is a free parameter describing the curve; it is an element of the complex projective line (the family of hypersurfaces in dimensions of degree n, defined analogously, has been intensively studied in recent years, in connection with the modularity theorem and its extensions). Thus, the base space o
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https://en.wikipedia.org/wiki/Tether%20car
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Tether cars (also commonly known as spindizzies) are model racing cars powered by miniature internal combustion engines and tethered to a central post. Unlike radio control cars, the driver has no remote control over the model's speed or steering.
Basics
Tether cars are often small (less than 1 meter in length), powered by a non-radio controlled model aeroplane engine (two stroke, glow plug, piston liner, etc.), and run on fuel supplied by a fuel tank within the car. Since 2015, electric motor driven cars, powered by batteries, have also emerged.
History
Tether cars were developed beginning in the 1920s–1930s and still are built, raced and collected today. First made by hobby craftsmen, tether cars were later produced in small numbers by commercial manufacturers such as Dooling Brothers (California), Dick McCoy (Duro-Matic Products), Garold Frymire (Fryco Engineering) BB Korn, and many others. Original examples of the early cars, made from 1930s to the 1960s, are avidly collected today and command prices in the thousands of dollars.
Locations and speed records
There are tracks in Australia (Brisbane and Sydney), New Zealand, Germany, Switzerland, Estonia, Ukraine, Russia, the United States, and other countries. World Championship races are held every 3 years, the 2013 World Championships was held in Basel, Switzerland.
World records
See also
Cox Models, a former manufacturer of ready to run tether cars
Control line flying model
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https://en.wikipedia.org/wiki/Tuning%20wrench
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A tuning wrench (also called a tuning lever or tuning hammer) is a specialized socket wrench used to tune string instruments, such as the piano, harp, and hammer dulcimer, that have strings wrapped around tuning pins. Other string instruments do not require a tuning wrench because their tuning pins or pegs come with handles (as with the violin), or geared tuning machines (as with the guitar or banjo).
Tuning wrench sockets may be triangular-shaped or eight-pointed star-shaped, and are found in two basic sizes: a large size for pianos, and a smaller size for most other instruments. For pianos, pins are typically square with a slight taper. There are three standard sizes known as No. 1, No. 2 and No. 3, for pins up to 6.5mm, for pins 6.5mm to 7.25mm, and for pins larger than 7.25mm. No. 2 is the most common. Wrenches are supplied with an eight-point star. Some early keyboard instruments have oblong-shaped tuning pins.
Impact piano tuning levers differ from traditional levers in that they are fitted with a weight at the end of the handle. The tuner flicks the lever with his or her wrist, causing the weight to do the actual work of moving the tuning pin. Tuning wrench sockets are often attached snugly to the handle with fine-gauge machine-screw threads, to provide a very firm, immobile joint; this is in contrast to the square snap-on joints found in sockets used for machinery.
Unlike most socket wrenches, tuning wrenches usually have a comfortable wood or nylon handle. They are found in two basic shapes: L-shaped and T-shaped. L-shaped handles for pianos are available in several angles that are not quite right angles, provide greater leverage than T-shaped handles, and the angle provides clearance for the handle over adjacent pins, allowing a very short and stiff socket to be used. This enables a better feel and control of the tiny movements of the tuning pin, within the pin-block. T-shaped handles are used for many lower-tension instruments such as the harpsichord,
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https://en.wikipedia.org/wiki/Subtropical%20front
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A subtropical front is a surface water mass boundary or front, which is a narrow zone of transition between air masses of contrasting density, air masses of different temperatures or different water vapour concentrates.
It is also characterized by an unforeseen change in wind direction, and speed across its surface between water systems, which are based on temperature and salinity. The subtropical separates the more saline subtropical waters from the fresher sub-Antarctic waters.
Subtropical frontal zone
A subtropical frontal zone (STFZ) is a large seasonal cycle located on the eastern side of basins. It is made up of fronts of multiple weak sea surface temperature (SST), aligned northwest–southeast, spread over a large latitudinal span. On the far eastern side of basins, the subtropical frontal zone becomes narrower and temperature gradients stronger, but still much weaker than across the dynamical subtropical frontal zone.
A dynamical frontal zone sits at the southern limit of the saline subtropical waters on the western sides of basins. There are no water mass boundaries or fronts in correlation with the sea surface temperature at the subtropical frontal zone at the surface or beneath.
The structure of a subtropical frontal zone results in the formation of a positive wind stress curl, which is the shear stress exerted by wind on the surface of water. The areas of most positive wind stress curl are characterized by very weak sea surface temperature incline, and are likely consistent to regions of mode water.
Northern subtropical front
The Northern subtropical front is found in the Pacific Ocean between 25° and 30° north latitude.
North Atlantic subtropical fronts
The North Atlantic subtropical fronts possess the characteristics of seasonal variability. Highest front occurrences are during early spring in the western region. Less front probability occurs in late spring to early summer in the eastern region. The strengths of the fronts differ with seasons, buil
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https://en.wikipedia.org/wiki/Abdominal%20aortic%20plexus
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The abdominal aortic plexus (not to be confused with the thoracic aortic plexus) is formed by branches derived, on either side, from the celiac plexus and ganglia, and receives filaments from some of the lumbar ganglia.
It is situated upon the sides and front of the aorta, between the origins of the superior and inferior mesenteric arteries.
From this plexus arise part of the spermatic, the inferior mesenteric, and the hypogastric plexuses; it also distributes filaments to the inferior vena cava.
The abdominal aortic plexus contains the spermatic ganglia, the inferior mesenteric ganglion, and the prehypogastric ganglion.
Additional images
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https://en.wikipedia.org/wiki/LM317
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The LM317 is a popular adjustable positive linear voltage regulator. It was designed by Bob Dobkin in 1976 while he worked at National Semiconductor.
The LM337 is the negative complement to the LM317, which regulates voltages below a reference. It was designed by Bob Pease, who also worked for National Semiconductor.
Specifications
Without a heat sink with an ambient temperature at 50 °C such as on a hot summer day inside a box, a maximum power dissipation of (TJ-TA)/RθJA = ((125-50)/80) = 0.98 W can be permitted. (A piece of shiny sheet metal of aluminium with the dimensions 6 x 6 cm and 1.5 mm thick, results in a thermal resistance that permits 4.7 W of heat dissipation).
In a constant voltage mode with an input voltage source at VIN at 34 V and a desired output voltage of 5 V, the maximum output current will be PMAX / (VIN-VO) = 0.98 / (34-5) = 32 mA.
For a constant current mode with an input voltage source at VIN at 12 V and a forward voltage drop of VF=3.6 V, the maximum output current will be PMAX / (VIN - VF) = 0.98 / (12-3.6) = 117 mA.
Operation
As linear regulators, the LM317 and LM337 are used in DC to DC converter applications.
Linear regulators inherently waste power; the power dissipated is the current passed multiplied by the voltage difference between input and output. A LM317 commonly requires a heat sink to prevent the operating temperature from rising too high. For large voltage differences, the power lost as heat can ultimately be greater than that provided to the circuit. This is the tradeoff for using linear regulators, which are a simple way to provide a stable voltage with few additional components. The alternative is to use a switching voltage regulator, which is usually more efficient, but has a larger footprint and requires a larger number of associated components.
In packages with a heat-dissipating mounting tab, such as TO-220, the tab is connected internally to the output pin which may make it necessary to electrically isolat
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https://en.wikipedia.org/wiki/List%20of%20interstitial%20cells
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Interstitial cell refers to any cell that lies in the spaces between the functional cells of a tissue.
Examples include:
Interstitial cell of Cajal (ICC)
Leydig cells, cells present in the male testes responsible for the production of androgen (male sex hormone)
A portion of the stroma of ovary
Certain cells in the pineal gland
Renal interstitial cells
neuroglial cells
See also
List of human cell types derived from the germ layers
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https://en.wikipedia.org/wiki/Beauvericin
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Beauvericin is a depsipeptide with antibiotic and insecticidal effects belonging to the enniatin family. It was isolated from the fungus Beauveria bassiana, but is also produced by several other fungi, including several Fusarium species; it may therefore occur in grain (such as corn, wheat and barley) contaminated with these fungi. Beauvericin is active against Gram-positive bacteria and mycobacteria, and is also capable of inducing programmed cell death in mammals.
Chemically, beauvericin is a cyclic hexadepsipeptide with alternating N-methyl-phenylalanyl and D-hydroxy-iso-valeryl residues. Its ion-complexing capability allows beauvericin to transport alkaline earth metal and alkali metal ions across cell membranes.
Beauvericin has in vitro fungicidal effects on Candida parapsilosis when used in combination with the antifungal drug ketoconazole at dosages of 0.1 μg/ml. Increased survivability rates and low cytotoxicity were also observed in mouse models.
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https://en.wikipedia.org/wiki/Oxford%20Calculators
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The Oxford Calculators were a group of 14th-century thinkers, almost all associated with Merton College, Oxford; for this reason they were dubbed "The Merton School". These men took a strikingly logical and mathematical approach to philosophical problems.
The key "calculators", writing in the second quarter of the 14th century, were Thomas Bradwardine, William Heytesbury, Richard Swineshead and John Dumbleton.
Using the slightly earlier works of Walter Burley, Gerard of Brussels, and Nicole Oresme, these individuals expanded upon the concepts of 'latitudes' and what real world applications they could apply them to.
Science
The advances these men made were initially purely mathematical but later became relevant to mechanics. Using Aristotelian logic and physics, they studied and attempted to quantify physical and observable characteristics such as: heat, force, color, density, and light. Aristotle believed that only length and motion were able to be quantified. But they used his philosophy and proved it untrue by being able to calculate things such as temperature and power.
They developed Al-Battani's work on trigonometry and their most famous work was the development of the mean speed theorem, (though it was later credited to Galileo) which is known as "The Law of Falling Bodies". Although they attempted to quantify these observable characteristics, their interests lay more in the philosophical and logical aspects than in natural world. They used numbers to disagree philosophically and prove the reasoning of "why" something worked the way it did and not only "how" something functioned the way that it did.
The Oxford Calculators distinguished kinematics from dynamics, emphasizing kinematics, and investigating instantaneous velocity. It is through their understanding of geometry and how different shapes could be used to represent a body in motion. The Calculators related these bodies in relative motion to geometrical shapes and also understood that a right triangle
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https://en.wikipedia.org/wiki/Lifting%20scheme
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The lifting scheme is a technique for both designing wavelets and performing the discrete wavelet transform (DWT). In an implementation, it is often worthwhile to merge these steps and design the wavelet filters while performing the wavelet transform. This is then called the second-generation wavelet transform. The technique was introduced by Wim Sweldens.
The lifting scheme factorizes any discrete wavelet transform with finite filters into a series of elementary convolution operators, so-called lifting steps, which reduces the number of arithmetic operations by nearly a factor two. Treatment of signal boundaries is also simplified.
The discrete wavelet transform applies several filters separately to the same signal. In contrast to that, for the lifting scheme, the signal is divided like a zipper. Then a series of convolution–accumulate operations across the divided signals is applied.
Basics
The simplest version of a forward wavelet transform expressed in the lifting scheme is shown in the figure above. means predict step, which will be considered in isolation. The predict step calculates the wavelet function in the wavelet transform. This is a high-pass filter. The update step calculates the scaling function, which results in a smoother version of the data.
As mentioned above, the lifting scheme is an alternative technique for performing the DWT using biorthogonal wavelets. In order to perform the DWT using the lifting scheme, the corresponding lifting and scaling steps must be derived from the biorthogonal wavelets. The analysis filters () of the particular wavelet are first written in polyphase matrix
where .
The polyphase matrix is a 2 × 2 matrix containing the analysis low-pass and high-pass filters, each split up into their even and odd polynomial coefficients and normalized. From here the matrix is factored into a series of 2 × 2 upper- and lower-triangular matrices, each with diagonal entries equal to 1. The upper-triangular matrices contain the co
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https://en.wikipedia.org/wiki/Fiber%20laser
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A fiber laser (or fibre laser in Commonwealth English) is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They are related to doped fiber amplifiers, which provide light amplification without lasing.
Fiber nonlinearities, such as stimulated Raman scattering or four-wave mixing can also provide gain and thus serve as gain media for a fiber laser.
Characteristics
An advantage of fiber lasers over other types of lasers is that the laser light is both generated and delivered by an inherently flexible medium, which allows easier delivery to the focusing location and target. This can be important for laser cutting, welding, and folding of metals and polymers. Another advantage is high output power compared to other types of laser. Fiber lasers can have active regions several kilometers long, and so can provide very high optical gain. They can support kilowatt levels of continuous output power because of the fiber's high surface area to volume ratio, which allows efficient cooling. The fiber's waveguide properties reduce or eliminate thermal distortion of the optical path, typically producing a diffraction-limited, high-quality optical beam. Fiber lasers are compact compared to solid-state or gas lasers of comparable power, because the fiber can be bent and coiled, except in the case of thicker rod-type designs, to save space. They have lower cost of ownership. Fiber lasers are reliable and exhibit high temperature and vibrational stability and extended lifetime. High peak power and nanosecond pulses improve marking and engraving. The additional power and better beam quality provide cleaner cut edges and faster cutting speeds.
Design and manufacture
Unlike most other types of lasers, the laser cavity in fiber lasers is constructed monolithically by fusion splicing different types of fiber; fiber Bragg gratings replace conventional diel
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https://en.wikipedia.org/wiki/Frequency%20comb
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In optics, a frequency comb is a laser source whose spectrum consists of a series of discrete, equally spaced frequency lines. Frequency combs can be generated by a number of mechanisms, including periodic modulation (in amplitude and/or phase) of a continuous-wave laser, four-wave mixing in nonlinear media, or stabilization of the pulse train generated by a mode-locked laser. Much work has been devoted to this last mechanism, which was developed around the turn of the 21st century and ultimately led to one half of the Nobel Prize in Physics being shared by John L. Hall and Theodor W. Hänsch in 2005.
The frequency domain representation of a perfect frequency comb is a series of delta functions spaced according to
where is an integer, is the comb tooth spacing (equal to the mode-locked laser's repetition rate or, alternatively, the modulation frequency), and is the carrier offset frequency, which is less than .
Combs spanning an octave in frequency (i.e., a factor of two) can be used to directly measure (and correct for drifts in) . Thus, octave-spanning combs can be used to steer a piezoelectric mirror within a carrier–envelope phase-correcting feedback loop. Any mechanism by which the combs' two degrees of freedom ( and ) are stabilized generates a comb that is useful for mapping optical frequencies into the radio frequency for the direct measurement of optical frequency.
Generation
Using a mode-locked laser
The most popular way of generating a frequency comb is with a mode-locked laser. Such lasers produce a series of optical pulses separated in time by the round-trip time of the laser cavity. The spectrum of such a pulse train approximates a series of Dirac delta functions separated by the repetition rate (the inverse of the round-trip time) of the laser.
This series of sharp spectral lines is called a frequency comb or a frequency Dirac comb.
The most common lasers used for frequency-comb generation are Ti:sapphire solid-state lasers or Er:fiber la
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https://en.wikipedia.org/wiki/NeuroNames
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NeuroNames is an integrated nomenclature for structures in the brain and spinal cord of the four species most studied by neuroscientists: human, macaque, rat and mouse. It offers a standard, controlled vocabulary of common names for structures, which is suitable for unambiguous neuroanatomical indexing of information in digital databases. Terms in the standard vocabulary have been selected for ease of pronunciation, mnemonic value, and frequency of use in recent neuroscientific publications. Structures and their relations to each other are defined in terms of the standard vocabulary. Currently NeuroNames contains standard names, synonyms and definitions of some 2,500 neuroanatomical entities.
The nomenclature is maintained by the University of Washington and is the core component of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain. One can either search by a structure name or locate the structure in a brain atlas and get information such as its location in the classical brain hierarchy, images of the structure, what cells it has, its connections and genes expressed there. Information can be accessed by any of some 16,000 synonyms in eight languages.
NeuroNames is a source vocabulary of the Metathesaurus of the Unified Medical Language System. It is described in depth in the following three scientific articles:
See also
NeuroLex
Neuroscience Information Framework
Talairach coordinates
External links
Overview of NeuroNames
BrainInfo
NeuroNames Direct Link
University of Washington
Neuroanatomy
Anatomical terminology
Anatomy websites
Biological databases
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