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https://en.wikipedia.org/wiki/Ore%27s%20theorem | Ore's theorem is a result in graph theory proved in 1960 by Norwegian mathematician Øystein Ore. It gives a sufficient condition for a graph to be Hamiltonian, essentially stating that a graph with sufficiently many edges must contain a Hamilton cycle. Specifically, the theorem considers the sum of the degrees of pairs of non-adjacent vertices: if every such pair has a sum that at least equals the total number of vertices in the graph, then the graph is Hamiltonian.
Formal statement
Let be a (finite and simple) graph with vertices. We denote by the degree of a vertex in , i.e. the number of incident edges in to . Then, Ore's theorem states that if
then is Hamiltonian.
Proof
It is equivalent to show that every non-Hamiltonian graph does not obey condition (∗). Accordingly, let be a graph on vertices that is not Hamiltonian, and let be formed from by adding edges one at a time that do not create a Hamiltonian cycle, until no more edges can be added. Let and be any two non-adjacent vertices in . Then adding edge to would create at least one new Hamiltonian cycle, and the edges other than in such a cycle must form a Hamiltonian path in with and . For each index in the range , consider the two possible edges in from to and from to . At most one of these two edges can be present in , for otherwise the cycle would be a Hamiltonian cycle. Thus, the total number of edges incident to either or is at most equal to the number of choices of , which is . Therefore, does not obey property (∗), which requires that this total number of edges () be greater than or equal to . Since the vertex degrees in are at most equal to the degrees in , it follows that also does not obey property (∗).
Algorithm
describes the following simple algorithm for constructing a Hamiltonian cycle in a graph meeting Ore's condition.
Arrange the vertices arbitrarily into a cycle, ignoring adjacencies in the graph.
While the cycle contains two consecutive vertices vi and v |
https://en.wikipedia.org/wiki/Anaplasia | Anaplasia (from ana, "backward" + πλάσις plasis, "formation") is a condition of cells with poor cellular differentiation, losing the morphological characteristics of mature cells and their orientation with respect to each other and to endothelial cells. The term also refers to a group of morphological changes in a cell (nuclear pleomorphism, altered nuclear-cytoplasmic ratio, presence of nucleoli, high proliferation index) that point to a possible malignant transformation.
Such loss of structural differentiation is especially seen in most, but not all, malignant neoplasms. Sometimes, the term also includes an increased capacity for multiplication. Lack of differentiation is considered a hallmark of aggressive malignancies (for example, it differentiates leiomyosarcomas from leiomyomas). The term anaplasia literally means "to form backward". It implies dedifferentiation, or loss of structural and functional differentiation of normal cells. It is now known, however, that at least some cancers arise from stem cells in tissues; in these tumors failure of differentiation, rather than dedifferentiation of specialized cells, account for undifferentiated tumors.
Anaplastic cells display marked pleomorphism (variability). The nuclei are characteristically extremely hyperchromatic (darkly stained) and large. The nuclear-cytoplasmic ratio may approach 1:1 instead of the normal 1:4 or 1:6. Giant cells that are considerably larger than their neighbors may be formed and possess either one enormous nucleus or several nuclei (syncytia). Anaplastic nuclei are variable and bizarre in size and shape. The chromatin is coarse and clumped, and nucleoli may be of astounding size. More important, mitoses are often numerous and distinctly atypical; anarchic multiple spindles may be seen and sometimes appear as tripolar or quadripolar forms. Also, anaplastic cells usually fail to develop recognizable patterns of orientation to one another (i.e., they lose normal polarity). They may grow i |
https://en.wikipedia.org/wiki/Vector%20fields%20on%20spheres | In mathematics, the discussion of vector fields on spheres was a classical problem of differential topology, beginning with the hairy ball theorem, and early work on the classification of division algebras.
Specifically, the question is how many linearly independent smooth nowhere-zero vector fields can be constructed on a sphere in -dimensional Euclidean space. A definitive answer was provided in 1962 by Frank Adams. It was already known, by direct construction using Clifford algebras, that there were at least such fields (see definition below). Adams applied homotopy theory and topological K-theory to prove that no more independent vector fields could be found. Hence is the exact number of pointwise linearly independent vector fields that exist on an ()-dimensional sphere.
Technical details
In detail, the question applies to the 'round spheres' and to their tangent bundles: in fact since all exotic spheres have isomorphic tangent bundles, the Radon–Hurwitz numbers determine the maximum number of linearly independent sections of the tangent bundle of any homotopy sphere. The case of odd is taken care of by the Poincaré–Hopf index theorem (see hairy ball theorem), so the case even is an extension of that. Adams showed that the maximum number of continuous (smooth would be no different here) pointwise linearly-independent vector fields on the ()-sphere is exactly .
The construction of the fields is related to the real Clifford algebras, which is a theory with a periodicity modulo 8 that also shows up here. By the Gram–Schmidt process, it is the same to ask for (pointwise) linear independence or fields that give an orthonormal basis at each point.
Radon–Hurwitz numbers
The Radon–Hurwitz numbers occur in earlier work of Johann Radon (1922) and Adolf Hurwitz (1923) on the Hurwitz problem on quadratic forms. For written as the product of an odd number and a power of two , write
.
Then
.
The first few values of are (from ):
2, 4, 2, 8, 2, 4, 2, 9, 2, 4 |
https://en.wikipedia.org/wiki/Levator%20veli%20palatini | The levator veli palatini () is a muscle of the soft palate and pharynx. It is innervated by the vagus nerve (cranial nerve X) via its pharyngeal plexus. During swallowing, it contracts, elevating the soft palate to help prevent food from entering the nasopharynx.
Structure
The levator veli palatini muscle occurs in the soft palate of the mouth. It forms a sling superior and immediately posterior to the palatine aponeurosis.
Origin
The primary site of origin of the muscle is a quadrangular roughened area upon the medial extremity of the inferior aspect of the petrous part of the temporal bone; here, the muscle arises by a small tendon.
Additional fibres of the muscle arise from the inferior aspect of the cartilaginous part of pharyngotympanic tube, and the vaginal process of sphenoid bone.
Insertion
In the medial third of the soft palate, its fibers spread out between the two strands of the palatoglossus muscle to attach to the superior surface of the palatine aponeurosis and intermingle with fibres of its contralateral partner.
Nerve supply
The levator veli palatini muscle receives motor innervation from the vagus nerve (CN X) via the pharyngeal plexus.
Relations
During its course from its origin to its insertion, the muscle passes medial to the superior margin of the superior pharyngeal constrictor muscle.
It lies lateral to the choana.
Actions/movements
The primary action of the muscle is to elevate and draw posterior-ward the nearly vertical posterior portion of the soft palate; thereby, the soft palate is brought into contact with the posterior wall of the pharynx, thus creating a barrier between the nasopharynx and oropharynx.
Additionally, the muscle draws the lateral walls of the nasopharynx posteromedially, thus narrowing the nasopharynx.
Function
The levator veli palatini muscle elevates the soft palate during swallowing. This helps to prevent food from entering the nasopharynx. Its action may be slightly slower than its partner, the tenso |
https://en.wikipedia.org/wiki/Superior%20longitudinal%20muscle%20of%20tongue | The superior longitudinal muscle of tongue or superior lingualis is a thin layer of oblique and longitudinal fibers immediately underlying the mucous membrane on the dorsum of the tongue.
Structure
The superior longitudinal muscle of the tongue is one of the intrinsic muscles of the tongue. It arises from the submucous fibrous layer close to the epiglottis and from the median fibrous septum, and runs forward to the edges of the tongue.
Nerve supply
The superior longitudinal muscle of the tongue is supplied by the hypoglossal nerve (CN XII).
Function
The superior longitudinal muscle of the tongue works with the other intrinsic muscles to move the tongue. |
https://en.wikipedia.org/wiki/Inferior%20longitudinal%20muscle%20of%20tongue | The inferior longitudinal muscle of tongue is an intrinsic muscle of the tongue. It is situated on the under surface of the tongue between the genioglossus and hyoglossus. It is innervated by the hypoglossal nerve (cranial nerve XII). Its contraction shortens and thickens the tongue.
Structure
The inferior longitudinal muscle of the tongue is an intrinsic muscle of the tongue. It is thin and oval in cross-section. It is situated between the paramedian septum, and the lateral septum. It extends from the root to the apex of the tongue. Posteriorly, some of its fibers attach onto the body of the hyoid bone. Anteriorly, its fibres blend with those of the styloglossus, hyoglossus, and genioglossus to form the ventral area of the tip of the tongue.
Innervation
The inferior longitudinal muscle of the tongue is supplied by the hypoglossal nerve (CN XII).
Function
Contraciton of the inferior longitudinal muscle of the tongue shortens and thickens the tongue.
Additional images |
https://en.wikipedia.org/wiki/Vertical%20muscle%20of%20tongue | The vertical muscle of the tongue is an intrinsic muscle of the tongue. Its fibers extend from the upper to the under surface of the tongue. It is innervated by the hypoglossal nerve (cranial nerve XII). Its contraction flattens, widens and elongates the tongue.
Anatomy
The vertical muscle of the tongue is an intrinsic muscle of the tongue. It is found only at the borders of the forepart of the tongue.
Structure
Fibres of the vertical muscle of the tongue are arranged in an almost vertical direction, and intersect the transversely oriented fibres of the transverse muscle of tongue. Fibers of the vertical muscle of the tongue extend from the upper to the under surface of the tongue.
Innervation
The vertical of the tongue is innervated by the hypoglossal nerve (CN XII).
Function
Contraction of the vertical muscle of the tongue flattens, widens and elongates the tongue. |
https://en.wikipedia.org/wiki/Transverse%20muscle%20of%20tongue | The transverse muscle of tongue (transversus linguae) is an intrinsic muscle of the tongue. It consists of fibers which arise from the median fibrous septum. It passes laterally to insert into the submucous fibrous tissue at the sides of the tongue. It is innervated by the hypoglossal nerve (cranial nerve XII). Its contraction elongates and narrows the tongue.
Structure
The transverse muscle of the tongue is an intrinsic muscle of the tongue. It consists of fibers which arise from the median fibrous septum. It passes laterally to insert into the submucous fibrous tissue at the sides of the tongue.
Innervation
The transverse lingual muscle is innervated by the hypoglossal nerve (CN XII).
Function
Contraction of the transverse muscle of the tongue elongates and narrows the tongue. |
https://en.wikipedia.org/wiki/Palatopharyngeus%20muscle | The palatopharyngeus (palatopharyngeal or pharyngopalatinus) muscle is a small muscle in the roof of the mouth.
It is a long, fleshy fasciculus, narrower in the middle than at either end, forming, with the mucous membrane covering its surface, the palatopharyngeal arch.
Structure
It is separated from the palatoglossus muscle by an angular interval, in which the palatine tonsil is lodged. It arises from the soft palate, where it is divided into two fasciculi by the levator veli palatini and musculus uvulae.
The posterior fasciculus lies in contact with the mucous membrane, and joins with that of the opposite muscle in the middle line.
The anterior fasciculus, the thicker, lies in the soft palate between the levator and tensor veli palatini muscles, and joins in the middle line the corresponding part of the opposite muscle.
Passing laterally and downward behind the palatine tonsil, the palatopharyngeus joins the stylopharyngeus and is inserted with that muscle into the posterior border of the thyroid cartilage, some of its fibers being lost on the side of the pharynx and others passing across the middle line posteriorly to decussate with the muscle of the opposite side.
Innervation
Motor innervation of this muscle is provided through the pharyngeal plexus of the CN X (vagal nerve), SVE (special visceral efferent) fibers.
Function
The palatine velum is slightly raised by the levator veli palatini and made tense by the tensor veli palatini; the palatopharyngeus muscles, by their contraction, pull the pharynx upward over the bolus of food and nearly come together, the uvula filling up the slight interval between them.
By these means the bolus is prevented from passing into the nasopharynx; at the same time, the palatopharyngeus muscles form an inclined plane, directed obliquely downward and backward, along the under surface of which the bolus descends into the lower part of the pharynx.
Additional images |
https://en.wikipedia.org/wiki/Salpingopharyngeus%20muscle | The salpingopharyngeus muscle is a muscle of the pharynx. It arises from the lower part of the cartilage of the Eustachian tube, and inserts into the palatopharyngeus muscle by blending with its posterior fasciculus. It is innervated by vagus nerve (cranial nerve X) via the pharyngeal plexus. It raises the pharynx and larynx during deglutition (swallowing) and laterally draws the pharyngeal walls up. It opens the pharyngeal orifice of the Eustachian tube during swallowing to allow for the equalization of pressure between it and the pharynx.
Structure
The salpingopharyngeus is a very slender muscle. It passes inferior-ward from its origin to its insertion within the salpingopharyngeal fold.
Origin
The salpingopharyngeus muscle arises from the inferior portion of the cartilaginous part of the pharyngotympanic tube near its pharyngeal opening. Its origin creates the posterior welt of the torus tubarius.
Insertion
It ends distally by blending with the palatopharyngeus muscle.
Innervation
The salpingopharyngeus receives motor innervation from the pharyngeal plexus of the vagus nerve.
Blood supply
The salpingopharyngeus muscle receives arterial supply from the ascending palatine artery, greater palatine artery, and the pharyngeal branch of the ascending pharyngeal artery.
Variation
The salpingopharyngeus muscle is absent in about 40% of individuals. It is more common in thin individuals.
Function
The salpingopharyngeus muscle raises the pharynx and larynx during deglutition (swallowing) and laterally draws the pharyngeal walls up. Unusually, it is relaxed during deglutition, but contracts at all other times. It opens the pharyngeal orifice of the Eustachian tube during swallowing allowing for the equalization of pressure between the it and the pharynx.
See also
Salpinx
Additional images |
https://en.wikipedia.org/wiki/Middle%20pharyngeal%20constrictor%20muscle | The middle pharyngeal constrictor is a fan-shaped muscle located in the neck. It is one of three pharyngeal constrictor muscles. It is smaller than the inferior pharyngeal constrictor muscle.
The middle pharyngeal constrictor originates from the greater cornu and lesser cornu of the hyoid bone, and the stylohyoid ligament. It inserts onto the pharyngeal raphe. It is innervated by a branch of the vagus nerve through the pharyngeal plexus. It acts to propel a bolus downwards along the pharynx towards the esophagus, facilitating swallowing.
Structure
The middle pharyngeal constrictor is a sheet-like, fan-shaped muscle.
The muscle's fibers diverge from their origin: the more inferior fibres descend deep to the inferior pharyngeal constrictor muscle; the middle portion of fibres pass transversely; the more superior fibers ascend and overlap the superior pharyngeal constrictor muscle.
Origin
Two parts of the middle pharyngeal constrictor muscle are distinguished according to its sites of origin:
Ceratopharyngeal part - arises (the entire superior margin of) the greater cornu of the hyoid bone.
Chondropharyngeal part - arises from the lesser cornu of the hyoid bone, and (the inferior portion of) the stylohyoid ligament. The chondropharyngeal part represents the muscle's anterior origin.
Insertion
The muscle inserts (posteriorly) into the pharyngeal raphe, blending with its contralateral partner at the midline.
Innervation
Similarly to the superior and inferior pharyngeal constrictor muscles, it is innervated by a branch of the vagus nerve through the pharyngeal plexus.
Actions/movements
The contraction of the muscle constricts the middle portion of the pharynx.
Function
The muscle contracts during swallowing: as soon as the bolus of food is received in the pharynx, the elevator muscles relax, the pharynx descends, and the constrictors contract upon the bolus, and convey it downward towards the esophagus.
They also have respiratory mechanical effects.
Addit |
https://en.wikipedia.org/wiki/Inferior%20pharyngeal%20constrictor%20muscle | The inferior pharyngeal constrictor muscle is a skeletal muscle of the neck. It is the thickest of the three outer pharyngeal muscles. It arises from the sides of the cricoid cartilage and the thyroid cartilage. It is supplied by the vagus nerve (CN X). It is active during swallowing, and partially during breathing and speech. It may be affected by Zenker's diverticulum.
Structure
The inferior pharyngeal constrictor muscle is composed of two parts. The first part (and more superior) arises from the thyroid cartilage (thyropharyngeal part), and the second part arises from the cricoid cartilage (cricopharyngeal part).
On the thyroid cartilage, it arises from the oblique line on the side of the lamina, from the surface behind this nearly as far as the posterior border and from the inferior horn of the thyroid cartilage.
From the cricoid cartilage, it arises in the interval between the cricothyroid muscle in front, and the articular facet for the inferior horn of the thyroid cartilage behind.
From these origins, the fibers spread backward and medially to insert with the muscle of the opposite side into the fibrous pharyngeal raphe in the posterior median line of the pharynx. The thyropharyngeal part mainly uses type 2 fibres (anaerobic), while the cricopharyngeal part mainly uses type 1 fibres (aerobic). Fibre type may change after birth.
The inferior fibers are horizontal and continuous with the circular fibers of the esophagus; the rest ascend, increasing in obliquity, and overlap the middle pharyngeal constrictor muscle. The cricopharyngeal part is synonymous with the upper esophageal sphincter (UES), which controls the opening of the cervical esophagus. It is sometimes referred to as the cricopharyngeal inlet.
Nerve supply
The inferior pharyngeal constrictor muscle can be supplied by branches from the pharyngeal plexus, the recurrent laryngeal nerve, the external branch of the superior laryngeal nerve, or a combination of these (the recurrent laryngeal nerv |
https://en.wikipedia.org/wiki/Superior%20pharyngeal%20constrictor%20muscle | The superior pharyngeal constrictor muscle is a quadrilateral muscle of the pharynx. It is the uppermost and thinnest of the three pharyngeal constrictors.
The muscle is divided into four parts according to its four distincts origins: a pterygopharyngeal, buccopharyngeal, mylopharyngeal, and a glossopharyngeal part. The muscle inserts onto the pharyngeal raphe, and pharyngeal spine. It is innervated by pharyngeal branch of the vagus nerve via the pharyngeal plexus. It acts to convey a bolus down towards the esophagus, facilitating swallowing.
Anatomy
The superior constrictor muscle is a quadrilateral, sheet-like muscle. It is thinner than the middle and inferior constrictor muscles.
Origin
The sites of origin of the muscles collectively are the pterygoid hamulus (and occasionally the adjoining posterior margin of the medial pterygoid plate) anteriorly, (the posterior margin of) the pterygomandibular raphe, the posterior extremity of the mylohyoid line of mandible, and (negligibly) the side of the tongue.
Four parts of the muscle are distinguished according to the origin:
Pterygopharyngeal part - originating from the lower third of the posterior margin of the medial pterygoid plate and its hamulus
Buccopharyngeal part - originating from the pterygomandibular raphe
Mylopharyngeal part - originating from the alveolar process of the mandible above the posterior end of the mylohyoid line
Glossopharyngeal part - a few fibers originating from the side of the tongue
Insertion
The muscle's fibres extend posterior-ward from its origin to form the midline pharyngeal raphe which then attaches onto the pharyngeal tubercle (of the basilar part of the occipital bone).
Innervation
The superior pharyngeal constrictor muscle receives motor innervation from the pharyngeal plexus of vagus nerve.
Vasculature
Arterial supply is provided primarily by the pharyngeal branch of the ascending pharyngeal artery, and the tonsilar branch of the facial artery.
Relations
The int |
https://en.wikipedia.org/wiki/Stylopharyngeus%20muscle | The stylopharyngeus muscle is a muscle in the head. It originates from the temporal styloid process. Some of its fibres insert onto the thyroid cartilage, while others end by intermingling with proximal structures. It is innervated by the glossopharyngeal nerve (cranial nerve IX). It acts to elevate the larynx and pharynx, and dilate the pharynx, thus facilitating swallowing.
Structure
The stylopharyngeus is a long, slender, tapered pharyngeal muscle. It is cylindrical superiorly, and flattened inferiorly.
It passes inferior-ward along the side of the pharynx between the superior pharyngeal constrictor (situated deep to the stylopharyngeus) and the middle pharyngeal constrictor (situated superficial to the stylopharyngeus), before spreads out beneath the mucous membrane.
Origin
It arises from (the medial side of the base of) the temporal styloid process.
It is the only muscle of the pharynx not to originate in the pharyngeal wall.
Insertion
Some of its fibers are lost in the superior and middle constrictor muscles, some merge with the lateral glossoepiglottic fold, while still others join with those of the palatopharyngeus muscle to insert onto the posterior border of the thyroid cartilage.
Innervation
The stylopharyngeus is the only muscle of the pharynx innervated by the glossopharyngeal nerve (CN IX) (all others being instead innervated by the vagus nerve (CN X)) by special visceral motor neurons with their cell bodies in the rostral part of the nucleus ambiguus.
Blood supply
The stylopharyngeus receives arterial supply from the paryngeal branch of the ascending pharyngeal artery.
Lymphatic drainage
The lymphatic drainage of the region of the stylopharyngeus muscle is mediated by the middle cervical lymph nodes that drain into the supraclavicular lymph nodes.
Relations
The stylopharyngeus is the medial-most and most vertical of the three styloid muscles.
The muscle is situated in between the external carotid artery and internal carotid artery.
On |
https://en.wikipedia.org/wiki/Tensor%20veli%20palatini%20muscle | The tensor veli palatini muscle (tensor palati or tensor muscle of the velum palatinum) is a thin, triangular muscle of the head that tenses the soft palate and opens the Eustachian tube to equalise pressure in the middle ear.
Structure
The tensor veli palatini muscle is thin and triangular in shape.
Origin
It arises from the scaphoid fossa of the pterygoid process of the sphenoid anteriorly, the (medial aspect of the) spine of sphenoid boneposteriorly, and - between the aforementioned anterior and posterior attachments - from the anterolateral aspect of the membranous wall of the petrotympanic tube.
At the muscle's origin, some of its muscle fibres may be continuous with those of the tensor tympani muscle.
Insertion
Inferiorly, the muscle converges to form a tendon of attachment. This tendon winds medially around the pterygoid hamulus (with a small bursa interposed between the two) to insert into the palatine aponeurosis and into the bony surface posterior to the palatine crest of the horizontal plate of palatine bone.
Dilator tubae component
Some of the muscle's fibres insert onto the lateral lamina of the cartilaginous part of pharyngotympanic tube and adjacent connective tissue, and the Ostmann's fat pad.
The portion of the muscle with these attachments is sometimes called the dilator tubae.
Innervation
The tensor veli palatini muscle receives motor innervation from the mandibular nerve (CN V3) (a branch of the trigeminal nerve (CN V)) via the nerve to medial pterygoid.
It is the only muscle of the palate not innervated by the pharyngeal plexus, which is formed by the vagal and glossopharyngeal nerves.
Relations
It is situated anterolaterally to the levator veli palatini muscle.
From its origin to its insertion, the muscle passes vertically between the medial pterygoid plate and the medial pterygoid muscle.
Actions/movements
Bilateral contraction of the two tensor veli palatini muscles makes the soft palate (especially its anterior portion) tau |
https://en.wikipedia.org/wiki/Thoracoacromial%20artery | The thoracoacromial artery (acromiothoracic artery; thoracic axis) is a short trunk that arises from the second part of the axillary artery, its origin being generally overlapped by the upper edge of the pectoralis minor.
Structure
Projecting forward to the upper border of the Pectoralis minor, it pierces the coracoclavicular fascia and divides into four branches—pectoral, acromial, clavicular, and deltoid.
Additional images |
https://en.wikipedia.org/wiki/Code%3A%3ABlocks | Code::Blocks is a free, open-source cross-platform IDE that supports multiple compilers including GCC, Clang and Visual C++. It is developed in C++ using wxWidgets as the GUI toolkit. Using a plugin architecture, its capabilities and features are defined by the provided plugins.
Currently, Code::Blocks is oriented towards C, C++, and Fortran. It has a custom build system and optional Make support.
Code::Blocks is being developed for Windows and Linux and has been ported to FreeBSD, OpenBSD and Solaris. The latest binary provided for macOS version is 13.12 released on 2013/12/26 (compatible with Mac OS X 10.6 and later), but more recent versions can be compiled and MacPorts supplies version 17.12.
History
After releasing two release candidate versions, 1.0rc1 on July 25, 2005 and 1.0rc2 on October 25, 2005, instead of making a final release, the project developers started adding many new features, with the final release being repeatedly postponed. Instead, there were nightly builds of the latest SVN version made available on a daily basis.
The first stable release was on February 28, 2008, with the version number changed to 8.02. The versioning scheme was changed to that of Ubuntu, with the major and minor number representing the year and month of the release. Version 20.03 is the latest stable release; however for the most up-to-date version the user can download the relatively stable nightly build or download the source code from SVN.
In April 2020, a critical software vulnerability was found in the Code::Blocks IDE v17.12, identified by CVE-2020-10814.
Jennic Limited distributes a version of Code::Blocks customized to work with its microcontrollers.
Features
Compilers
Code::Blocks supports multiple compilers, including GCC, MinGW, Digital Mars, Microsoft Visual C++, Borland C++, LLVM Clang, Watcom, LCC and the Intel C++ compiler. Although the IDE was designed for the C++ language, there is some support for other languages, including Fortran and D. A plug-i |
https://en.wikipedia.org/wiki/Vector%20area | In 3-dimensional geometry and vector calculus, an area vector is a vector combining an area quantity with a direction, thus representing an oriented area in three dimensions.
Every bounded surface in three dimensions can be associated with a unique area vector called its vector area. It is equal to the surface integral of the surface normal, and distinct from the usual (scalar) surface area.
Vector area can be seen as the three dimensional generalization of signed area in two dimensions.
Definition
For a finite planar surface of scalar area and unit normal , the vector area is defined as the unit normal scaled by the area:
For an orientable surface composed of a set of flat facet areas, the vector area of the surface is given by
where is the unit normal vector to the area .
For bounded, oriented curved surfaces that are sufficiently well-behaved, we can still define vector area. First, we split the surface into infinitesimal elements, each of which is effectively flat. For each infinitesimal element of area, we have an area vector, also infinitesimal.
where is the local unit vector perpendicular to . Integrating gives the vector area for the surface.
Properties
The vector area of a surface can be interpreted as the (signed) projected area or "shadow" of the surface in the plane in which it is greatest; its direction is given by that plane's normal.
For a curved or faceted (i.e. non-planar) surface, the vector area is smaller in magnitude than the actual surface area. As an extreme example, a closed surface can possess arbitrarily large area, but its vector area is necessarily zero. Surfaces that share a boundary may have very different areas, but they must have the same vector area—the vector area is entirely determined by the boundary. These are consequences of Stokes' theorem.
The vector area of a parallelogram is given by the cross product of the two vectors that span it; it is twice the (vector) area of the triangle formed by the same vector |
https://en.wikipedia.org/wiki/Storage%20service%20provider | A Storage service provider (SSP) is any company that provides computer storage space and related management services. SSPs may also offer periodic backup and archiving.
Advantages of managed storage are that more space can be ordered as required. Depending upon your SSP, backups may also be managed.
Faster data access can be ordered as required. Also, maintenance costs may be reduced, particularly for larger organizations who store a large or increasing volumes of data. Another advantage is that best practices are likely to be followed. Disadvantages are that the cost may be prohibitive, for small organizations or individuals who deal with smaller amounts or static volumes of data and that there's less control of data systems.
Types of managed storage
Data owners normally access managed storage via a network (LAN), or through a series of networks (Internet). However, managed storage may be directly attached to a workstation or server, which is not managed by SSP.
Managed Storage generally falls into one of the following categories:
locally managed storage
remotely managed storage
Locally managed storage
Advantages of this type of storage include a high-speed access to data and greater control over data availability. A disadvantage is that additional space is required at a local site to store the data, as well as limitations of the on-site area.
Remotely managed storage
Advantages of this type of storage are that it may be used an off site backup, it offers global access (depending upon configuration) and adding storage will not require additional space at the local site. However, if the network providing connectivity to the remote data is interrupted, there will be data availability issues, unless distributed file systems are in use.
In cloud computing, Storage as a Service (SaaS) involves the provision of off-site storage for data and information. This approach may offer greater reliability, but at a higher cost.
See also
Application service provider
Int |
https://en.wikipedia.org/wiki/Hypholoma%20capnoides | Hypholoma capnoides is an edible mushroom in the family Strophariaceae. Like its poisonous relative H. fasciculare ("sulphur tuft"), H. capnoides grows in clusters on decaying wood, for example in tufts on old tree stumps, in North America, Europe, and Asia.
Edibility
Though edible, the poisonous sulphur tuft is more common in many areas. H. capnoides has greyish gills due to the dark color of its spores, whereas sulphur tuft has greenish gills. It could also perhaps be confused with the deadly Galerina marginata or the good edible Kuehneromyces mutabilis.
Description
Cap: Up to 6 cm in diameter with yellow-to-orange-brownish or matt yellow colour, sometimes viscid.
Gills: Initially pale orangish-yellow, pale grey when mature, later darker purple/brown.
Spore powder: Dark burgundy/brown.
Stipe: Yellowish, somewhat rust-brown below.
Taste: Mild (other Hypholomas mostly have a bitter taste). |
https://en.wikipedia.org/wiki/Thomson%20problem | The objective of the Thomson problem is to determine the minimum electrostatic potential energy configuration of electrons constrained to the surface of a unit sphere that repel each other with a force given by Coulomb's law. The physicist J. J. Thomson posed the problem in 1904 after proposing an atomic model, later called the plum pudding model, based on his knowledge of the existence of negatively charged electrons within neutrally-charged atoms.
Related problems include the study of the geometry of the minimum energy configuration and the study of the large behavior of the minimum energy.
Mathematical statement
The electrostatic interaction energy occurring between each pair of electrons of equal charges (, with the elementary charge of an electron) is given by Coulomb's law,
where is the electric constant and is the distance between each pair of electrons located at points on the sphere defined by vectors and , respectively.
Simplified units of and (the Coulomb constant) are used without loss of generality. Then,
The total electrostatic potential energy of each N-electron configuration may then be expressed as the sum of all pair-wise interaction energies
The global minimization of over all possible configurations of N distinct points is typically found by numerical minimization algorithms.
Thomson's problem is related to the 7th of the eighteen unsolved mathematics problems proposed by the mathematician Steve Smale — "Distribution of points on the 2-sphere".
The main difference is that in Smale's problem the function to minimise is not the electrostatic potential but a logarithmic potential given by A second difference is that Smale's question is about the asymptotic behaviour of the total potential when the number N of points goes to infinity, not for concrete values of N.
Example
The solution of the Thomson problem for two electrons is obtained when both electrons are as far apart as possible on opposite sides of the origin, , or
K |
https://en.wikipedia.org/wiki/3-Phosphoglyceric%20acid | 3-Phosphoglyceric acid (3PG, 3-PGA, or PGA) is the conjugate acid of 3-phosphoglycerate or glycerate 3-phosphate (GP or G3P). This glycerate is a biochemically significant metabolic intermediate in both glycolysis and the Calvin-Benson cycle. The anion is often termed as PGA when referring to the Calvin-Benson cycle. In the Calvin-Benson cycle, 3-phosphoglycerate is typically the product of the spontaneous scission of an unstable 6-carbon intermediate formed upon CO2 fixation. Thus, two equivalents of 3-phosphoglycerate are produced for each molecule of CO2 that is fixed. In glycolysis, 3-phosphoglycerate is an intermediate following the dephosphorylation (reduction) of 1,3-bisphosphoglycerate.
Glycolysis
In the glycolytic pathway, 1,3-bisphosphoglycerate is dephosphorylated to form 3-phosphoglyceric acid in a coupled reaction producing two ATP via substrate-level phosphorylation. The single phosphate group left on the 3-PGA molecule then moves from an end carbon to a central carbon, producing 2-phosphoglycerate. This phosphate group relocation is catalyzed by phosphoglycerate mutase, an enzyme that also catalyzes the reverse reaction.
Calvin-Benson cycle
In the light-independent reactions (also known as the Calvin-Benson cycle), two 3-phosphoglycerate molecules are synthesized. RuBP, a 5-carbon sugar, undergoes carbon fixation, catalyzed by the rubisco enzyme, to become an unstable 6-carbon intermediate. This intermediate is then cleaved into two, separate 3-carbon molecules of 3-PGA. One of the resultant 3-PGA molecules continues through the Calvin-Benson cycle to be regenerated into RuBP while the other is reduced to form one molecule of glyceraldehyde 3-phosphate (G3P) in two steps: the phosphorylation of 3-PGA into 1,3-bisphosphoglyceric acid via the enzyme phosphoglycerate kinase (the reverse of the reaction seen in glycolysis) and the subsequent catalysis by glyceraldehyde 3-phosphate dehydrogenase into G3P. G3P eventually reacts to form the sugars such |
https://en.wikipedia.org/wiki/1%2C3-Bisphosphoglyceric%20acid | 1,3-Bisphosphoglyceric acid (1,3-Bisphosphoglycerate or 1,3BPG) is a 3-carbon organic molecule present in most, if not all, living organisms. It primarily exists as a metabolic intermediate in both glycolysis during respiration and the Calvin cycle during photosynthesis. 1,3BPG is a transitional stage between glycerate 3-phosphate and glyceraldehyde 3-phosphate during the fixation/reduction of CO2. 1,3BPG is also a precursor to 2,3-bisphosphoglycerate which in turn is a reaction intermediate in the glycolytic pathway.
Biological structure and role
1,3-Bisphosphoglycerate is the conjugate base of 1,3-bisphosphoglyceric acid. It is phosphorylated at the number 1 and 3 carbons. The result of this phosphorylation gives 1,3BPG important biological properties such as the ability to phosphorylate ADP to form the energy storage molecule ATP.
In glycolysis
As previously mentioned 1,3BPG is a metabolic intermediate in the glycolytic pathway. It is created by the exergonic oxidation of the aldehyde in G3P. The result of this oxidation is the conversion of the aldehyde group into a carboxylic acid group which drives the formation of an acyl phosphate bond. This is incidentally the only step in the glycolytic pathway in which NAD+ is converted into NADH. The formation reaction of 1,3BPG requires the presence of an enzyme called glyceraldehyde-3-phosphate dehydrogenase.
The high-energy acyl phosphate bond of 1,3BPG is important in respiration as it assists in the formation of ATP. The molecule of ATP created during the following reaction is the first molecule produced during respiration. The reaction occurs as follows;
1,3-bisphosphoglycerate + ADP ⇌ 3-phosphoglycerate + ATP
The transfer of an inorganic phosphate from the carboxyl group on 1,3BPG to ADP to form ATP is reversible due to a low ΔG. This is as a result of one acyl phosphate bond being cleaved whilst another is created. This reaction is not naturally spontaneous and requires the presence of a catalyst. Thi |
https://en.wikipedia.org/wiki/Disk%20pack | Disk packs and disk cartridges were early forms of removable media for computer data storage, introduced in the 1960s.
Disk pack
A disk pack is a layered grouping of hard disk platters (circular, rigid discs coated with a magnetic data storage surface). A disk pack is the core component of a hard disk drive. In modern hard disks, the disk pack is permanently sealed inside the drive. In many early hard disks, the disk pack was a removable unit, and would be supplied with a protective canister featuring a lifting handle.
The protective cover consisted of two parts, a plastic shell, with a handle in the center, that enclosed the top and sides of the disks and a separate bottom that completed the sealed package. To remove the disk pack, the drive would be taken off line and allowed to spin down. Its access door could then be opened and an empty shell inserted and twisted to unlock the disk platter from the drive and secure it to the shell. The assembly would then be lifted out and the bottom cover attached. A different disk pack could then be inserted by removing the bottom and placing the disk pack with its shell into the drive. Turning the handle would lock the disk pack in place and free the shell for removal.
The first removable disk pack was invented in 1961 by IBM engineers R. E. Pattison as part of the LCF (Low Cost File) project headed by Jack Harker. The 14-inch (356 mm) diameter disks introduced by IBM became a de facto standard, with many vendors producing disk drives using 14-inch disks in disk packs and cartridges into the 1980s.
Examples of disk drives that employed removable disk packs include the IBM 1311, IBM 2311, and the Digital RP04.
Disk cartridge
An early disk cartridge was a single hard disk platter encased in a protective plastic shell. When the removable cartridge was inserted into the cartridge drive peripheral device, the read/write heads of the drive could access the magnetic data storage surface of the platter through holes in the sh |
https://en.wikipedia.org/wiki/Diurnality | Diurnality is a form of plant and animal behavior characterized by activity during daytime, with a period of sleeping or other inactivity at night. The common adjective used for daytime activity is "diurnal". The timing of activity by an animal depends on a variety of environmental factors such as the temperature, the ability to gather food by sight, the risk of predation, and the time of year. Diurnality is a cycle of activity within a 24-hour period; cyclic activities called circadian rhythms are endogenous cycles not dependent on external cues or environmental factors except for a zeitgeber. Animals active during twilight are crepuscular, those active during the night are nocturnal and animals active at sporadic times during both night and day are cathemeral.
Plants that open their flowers during the daytime are described as diurnal, while those that bloom during nighttime are nocturnal. The timing of flower opening is often related to the time at which preferred pollinators are foraging. For example, sunflowers open during the day to attract bees, whereas the night-blooming cereus opens at night to attract large sphinx moths.
In animals
Many types of animals are classified as being diurnal, meaning they are active during the day time and inactive or have periods of rest during the night time. Commonly classified diurnal animals include mammals, birds, and reptiles. Most primates are diurnal, including humans. Scientifically classifying diurnality within animals can be a challenge, apart from the obvious increased activity levels during the day time light.
Evolution of diurnality
Initially, most animals were diurnal, but adaptations that allowed some animals to become nocturnal is what helped contribute to the success of many, especially mammals. This evolutionary movement to nocturnality allowed them to better avoid predators and gain resources with less competition from other animals. This did come with some adaptations that mammals live with today. Visi |
https://en.wikipedia.org/wiki/Sever%27s%20disease | Sever's disease, also known as calcaneus apophysitis, is an inflammation at the back of the heel (or calcaneus) growth plate in growing children. The condition is thought to be caused by repetitive stress at the heel. This condition is benign and common and usually resolves when the growth plate has closed or during periods of less activity. It occurs in both males and females. There are a number of locations in the body that may get apophysitis pain. Another common location is at the front of the knee which is known as apophysitis of the tibial tuberosity or Osgood–Schlatter disease.
Symptoms
Children with calcaneal apophysitis commonly complain of pain at the back of the heel. This pain increases with jumping and some running sports.
Sometimes, the pain makes children limp and may result in poor sports performance or them not wanting to participate in some sports. The back of the heel is never swollen or red, unless there has been shoe rubbing. When the back of the heel is squeezed from the inside and outside, children with calcaneal apophysitis will report pain. Foot radiographs are not needed to diagnose calcaneal apophysitis as the growth plate can look similar with or without pain. Health professionals should only refer for imaging when the symptoms don't match with the usual presentation or there has been an injury that has resulted in heel pain. Therefore, the diagnosis of Sever's disease is primarily from history and physical assessment.
Cause
There are no known causes of calcaneal apophysitis or any ways that it can be prevented. Instead there are things that may contribute to calcaneal apophysitis developing. Children who complain of this type of heel pain commonly are taller (may have just had a growth spurt) or heavier. They also often play sports that have higher jumping, running or direction changes like basketball or soccer. It can also occur more in children who play on hard surfaces. Sometimes children who also start a new sport also complain on |
https://en.wikipedia.org/wiki/Phoning%20home | In computing, phoning home is a term often used to refer to the behavior of security systems that report network location, username, or other such data to another computer.
Phoning home may be useful for the proprietor in tracking a missing or stolen computer. In this way, it is frequently performed by mobile computers at corporations. It typically involves a software agent which is difficult to detect or remove. However, phoning home can also be malicious, as in surreptitious communication between end-user applications or hardware and its manufacturers or developers. The traffic may be encrypted to make it difficult or impractical for the end user to determine what data are being transmitted.
The Stuxnet attack on Iran's nuclear facilities was facilitated by phone-home technology as reported by The New York Times.
Legally phoning home
Some uses for the practice are legal in some countries. For example, phoning home could be for access restriction, such as transmitting an authorization key. This was done with the Adobe Creative Suite: Each time one of the programs is opened, it phones home with the serial number. If the serial number is already in use, or a fake, then the program will present the user with the option of entering the correct serial number. If the user refuses, the next time the program loads, it will operate in trial mode until a valid serial number has been entered. However, the method can be thwarted by either disabling the internet connection when starting the program or adding a firewall or Hosts file rule to prevent the program from communicating with the verification server.
Phoning home could also be for marketing purposes, such as the "Sony BMG rootkit", which transmits a hash of the currently playing CD back to Sony, or a digital video recorder (DVR) reporting on viewing habits. High-end computing systems such as mainframes have been able to phone home for many years, to alert the manufacturer of hardware problems with the mainframes or |
https://en.wikipedia.org/wiki/Temporal%20mean | The temporal mean is the arithmetic mean of a series of values over a time period. Assuming equidistant measuring or sampling times, it can be computed as the sum of the values over a period divided by the number of values. A simple moving average can be considered to be a sequence of temporal means over periods of equal duration. (If the time variable is continuous, the average value during the time period is the integral over the period divided by the length of the duration of the period.)
See also
Moving average |
https://en.wikipedia.org/wiki/Iconoscope | The iconoscope (from the Greek: εἰκών "image" and σκοπεῖν "to look, to see") was the first practical video camera tube to be used in early television cameras. The iconoscope produced a much stronger signal than earlier mechanical designs, and could be used under any well-lit conditions. This was the first fully electronic system to replace earlier cameras, which used special spotlights or spinning disks to capture light from a single very brightly lit spot.
Some of the principles of this apparatus were described when Vladimir Zworykin filed two patents for a television system in 1923 and 1925. A research group at Westinghouse Electronic Company headed by Zworykin presented the iconoscope to the general public in a press conference in June 1933, and two detailed technical papers were published in September and October of the same year. The German company Telefunken bought the rights from RCA and built the superikonoskop camera used for the historical TV transmission at the 1936 Summer Olympics in Berlin.
The iconoscope was replaced in Europe around 1936 by the much more sensitive Super-Emitron and Superikonoskop, while in the United States the iconoscope was the leading camera tube used for broadcasting from 1936 until 1946, when it was replaced by the image orthicon tube.
Discovery of a New Physical Phenomenon
In a Technikatörténeti Szemle article, subsequently reissued on the internet, entitled The Iconoscope: Kálmán Tihanyi and the Development of Modern Television, Tihanyi's daughter Katalin Tihanyi Glass notes that her father found the "storage principle" included a "new physical phenomenon", the photoconductive effect:
Operation
The main image forming element in the iconoscope was a mica plate with a pattern of photosensitive granules deposited on the front using an electrically insulating glue. The granules were typically made of silver grains covered with caesium or caesium oxide. The back of the mica plate, opposite the granules, was covered with a thin |
https://en.wikipedia.org/wiki/Petr%20Vop%C4%9Bnka | Petr Vopěnka (16 May 1935 – 20 March 2015) was a Czech mathematician. In the early seventies, he developed alternative set theory (i.e. alternative to the classical Cantor theory), which he subsequently developed in a series of articles and monographs. Vopěnka’s name is associated with many mathematical achievements, including Vopěnka's principle.
Since the mid-eighties he concerned himself with philosophical questions of mathematics (particularly vis-à-vis Husserlian phenomenology).
Vopěnka served as the Minister of Education of the Czech Republic (then part of Czechoslovakia) from 1990 to 1992 within the government of Prime Minister Petr Pithart.
Biography
Petr Vopěnka grew up in small town of Dolní Kralovice. After finishing gymnasium in Ledeč nad Sázavou in 1953 he went to study mathematics at the Mathematics and Physics Faculty of Charles University in Prague, graduating in 1958. In 1962 he was made Candidate of Sciences (CSc) and in 1967 Doctor of Science (DrSc). His advisors were Eduard Čech and Ladislav Rieger.
Starting in 1958 Vopěnka taught at the Mathematics and Physics Faculty, since 1964 as lecturer, since 1965 as senior lecturer. In 1968 he was made professor but was prevented to take this title until 1990 due to political reasons. Between 1966 and 1969 Vopěnka served as Vice Dean of the faculty.
In 1967 Vopěnka became head of the newly established Department of Mathematical Logic. The department was abolished in 1970 and Vopěnka, though allowed to stay at the university, fell into disfavour with the regime, which limited his contacts with foreign mathematicians. During the 1970s and 1980s he concentrated on philosophy and history of mathematics and on phenomenology of infinity.
After the Velvet Revolution, in January 1990, Vopěnka became Deputy Rector of the Charles University. During the period June 1990 – July 1992 he served as Minister of Education of the Czech Republic (then part of Czechoslovakia). In this position he, without much of suc |
https://en.wikipedia.org/wiki/Osteochondritis | Osteochondritis is a painful type of osteochondrosis where the cartilage or bone in a joint is inflamed.
It often refers to osteochondritis dissecans (OCD). The term dissecans refers to the "creation of a flap of cartilage that further dissects away from its underlying subchondral attachments (dissecans)".
The other recognized types of osteochondritis are osteochondritis deformans juvenilis (osteochondritis of the capitular head of the epiphysis of the femur) and osteochondritis deformans juvenilis dorsi (osteochondrosis of the spinal vertebrae, also known as Scheuermann's disease).
Osteochondritis, and especially osteochondritis dissecans, can manifest in animals as a primary cause of elbow dysplasia, a chronic condition in some dog breeds. |
https://en.wikipedia.org/wiki/Confounding | In causal inference, a confounder (also confounding variable, confounding factor, extraneous determinant or lurking variable) is a variable that influences both the dependent variable and independent variable, causing a spurious association. Confounding is a causal concept, and as such, cannot be described in terms of correlations or associations. The existence of confounders is an important quantitative explanation why correlation does not imply causation. Some notations are explicitly designed to identify the existence, possible existence, or non-existence of confounders in causal relationships between elements of a system.
Confounds are threats to internal validity.
Definition
Confounding is defined in terms of the data generating model. Let X be some independent variable, and Y some dependent variable. To estimate the effect of X on Y, the statistician must suppress the effects of extraneous variables that influence both X and Y. We say that X and Y are confounded by some other variable Z whenever Z causally influences both X and Y.
Let be the probability of event Y = y under the hypothetical intervention X = x. X and Y are not confounded if and only if the following holds:
for all values X = x and Y = y, where is the conditional probability upon seeing X = x. Intuitively, this equality states that X and Y are not confounded whenever the observationally witnessed association between them is the same as the association that would be measured in a controlled experiment, with x randomized.
In principle, the defining equality can be verified from the data generating model, assuming we have all the equations and probabilities associated with the model. This is done by simulating an intervention (see Bayesian network) and checking whether the resulting probability of Y equals the conditional probability . It turns out, however, that graph structure alone is sufficient for verifying the equality .
Control
Consider a researcher attempting to assess the effe |
https://en.wikipedia.org/wiki/Rankine%20vortex | The Rankine vortex is a simple mathematical model of a vortex in a viscous fluid. It is named after its discoverer, William John Macquorn Rankine.
The vortices observed in nature are usually modelled with an irrotational (potential or free) vortex. However, in potential vortex, the velocity becomes infinite at the vortex center. In reality, very close to the origin, the motion resembles a solid body rotation. The Rankine vortex model assumes a solid-body rotation inside a cylinder of radius and a potential vortex outside the cylinder. The radius is referred to as the vortex-core radius. The velocity components of the Rankine vortex, expressed in terms of the cylindrical-coordinate system are given by
where is the circulation strength of the Rankine vortex. Since solid-body rotation is characterized by an azimuthal velocity , where is the constant angular velocity, one can also use the parameter to characterize the vortex.
The vorticity field associated with the Rankine vortex is
At all points inside the core of the Rankine vortex, the vorticity is uniform at twice the angular velocity of the core; whereas vorticity is zero at all points outside the core because the flow there is irrotational.
In reality, vortex cores are not always circular; and vorticity is not exactly uniform throughout the vortex core.
See also
Kaufmann (Scully) vortex – an alternative mathematical simplification for a vortex, with a smoother transition.
Lamb–Oseen vortex – the exact solution for a free vortex decaying due to viscosity.
Burgers vortex |
https://en.wikipedia.org/wiki/RE%20%28complexity%29 | In computability theory and computational complexity theory, RE (recursively enumerable) is the class of decision problems for which a 'yes' answer can be verified by a Turing machine in a finite amount of time. Informally, it means that if the answer to a problem instance is 'yes', then there is some procedure that takes finite time to determine this, and this procedure never falsely reports 'yes' when the true answer is 'no'. However, when the true answer is 'no', the procedure is not required to halt; it may go into an "infinite loop" for some 'no' cases. Such a procedure is sometimes called a semi-algorithm, to distinguish it from an algorithm, defined as a complete solution to a decision problem.
Similarly, co-RE is the set of all languages that are complements of a language in RE. In a sense, co-RE contains languages of which membership can be disproved in a finite amount of time, but proving membership might take forever.
Equivalent definition
Equivalently, RE is the class of decision problems for which a Turing machine can list all the 'yes' instances, one by one (this is what 'enumerable' means).
Each member of RE is a recursively enumerable set and therefore a Diophantine set.
To show this is equivalent, note that if there is a machine that enumerates all accepted inputs, another machine that takes in a string can run and accept if the string is enumerated. Conversely, if a machine accepts when an input is in a language, another machine can enumerate all strings in the language by interleaving simulations of on every input and outputting strings that are accepted (there is an order of execution that will eventually get to every execution step because there are countably many ordered pairs of inputs and steps).
Relations to other classes
The set of recursive languages (R) is a subset of both RE and co-RE. In fact, it is the intersection of those two classes, because we can decide any problem for which there exists a recogniser and also a co-recogni |
https://en.wikipedia.org/wiki/R%20%28complexity%29 | In computational complexity theory, R is the class of decision problems solvable by a Turing machine, which is the set of all recursive languages (also called decidable languages).
Equivalent formulations
R is equivalent to the set of all total computable functions in the sense that:
a decision problem is in R if and only if its indicator function is computable,
a total function is computable if and only if its graph is in R.
Relationship with other classes
Since we can decide any problem for which there exists a recogniser and also a co-recogniser by simply interleaving them until one obtains a result, the class is equal to RE ∩ co-RE. |
https://en.wikipedia.org/wiki/Three-center%20four-electron%20bond | The 3-center 4-electron (3c–4e) bond is a model used to explain bonding in certain hypervalent molecules such as tetratomic and hexatomic interhalogen compounds, sulfur tetrafluoride, the xenon fluorides, and the bifluoride ion. It is also known as the Pimentel–Rundle three-center model after the work published by George C. Pimentel in 1951, which built on concepts developed earlier by Robert E. Rundle for electron-deficient bonding. An extended version of this model is used to describe the whole class of hypervalent molecules such as phosphorus pentafluoride and sulfur hexafluoride as well as multi-center π-bonding such as ozone and sulfur trioxide.
There are also molecules such as diborane (B2H6) and dialane (Al2H6) which have three-center two-electron bond (3c-2e) bonds.
History
While the term "hypervalent" was not introduced in the chemical literature until 1969, Irving Langmuir and G. N. Lewis debated the nature of bonding in hypervalent molecules as early as 1921. While Lewis supported the viewpoint of expanded octet, invoking s-p-d hybridized orbitals and maintaining 2c–2e bonds between neighboring atoms, Langmuir instead opted for maintaining the octet rule, invoking an ionic basis for bonding in hypervalent compounds (see Hypervalent molecule, valence bond theory diagrams for PF5 and SF6).
In a 1951 seminal paper, Pimentel rationalized the bonding in hypervalent trihalide ions (, X = F, Br, Cl, I) via a molecular orbital (MO) description, building on the concept of the "half-bond" introduced by Rundle in 1947. In this model, two of the four electrons occupy an all in-phase bonding MO, while the other two occupy a non-bonding MO, leading to an overall bond order of 0.5 between adjacent atoms (see Molecular orbital description).
More recent theoretical studies on hypervalent molecules support the Langmuir view, confirming that the octet rule serves as a good first approximation to describing bonding in the s- and p-block elements.
Examples of molecules |
https://en.wikipedia.org/wiki/G-Market | Gmarket is an e-commerce website based in South Korea. The company was founded in 2000 as a subsidiary of Interpark, and was acquired by eBay in 2009, who subsequently sold it to Shinsegae at 3.4 trillion Korean Won.
History and Incidents
The predecessor of Gmarket was founded in 1999 by Young Bae Ku. At the time, it was part of the online auction company Interpark. In 2000, it spun off as its own website, known as Goodsdaq. In 2003, the website was renamed Gmarket and adopted a customer to customer e-commerce business model.
In 2006, Gmarket became the first South Korean online company to be listed on the NASDAQ. That same year, it launched its global website with product listings in English.
In 2009, eBay acquired Gmarket for approximately 1.2 billion USD after buying Gmarket shares from Interpark and Yahoo. Following the acquisition, Gmarket was delisted from the NASDAQ.
After the acquisition, G-Market received an on-site investigation by the Fair Trade Commission for allegations of unfair trade due to 11street's report of abuse of market dominant status, and was charged with a corrective order and fine from the Fair Trade Commission as well as being charged with prosecution.
However, the following year, the 6th Division of the Seoul Central District Prosecutor's Office concluded that the case was not suspicious. An official at the prosecution said, "The number of sellers who actually stopped trading with '11street' was so small that the effect of restricting competition was not reached, and it was acknowledged that the eBay Market side performed its usual management and supervision duties to prevent unfair trade, so it was disposed of without charge."
Items and services
Collectibles, appliances, computers, furniture, equipment, vehicles, and other miscellaneous items are listed, bought, and sold. Large international companies such as LG and Samsung also sell their newest products and offer services using competitive auctions and fixed-priced storefronts. R |
https://en.wikipedia.org/wiki/Endometritis | Endometritis is inflammation of the inner lining of the uterus (endometrium). Symptoms may include fever, lower abdominal pain, and abnormal vaginal bleeding or discharge. It is the most common cause of infection after childbirth. It is also part of spectrum of diseases that make up pelvic inflammatory disease.
Endometritis is divided into acute and chronic forms. The acute form is usually from an infection that passes through the cervix as a result of an abortion, during menstruation, following childbirth, or as a result of douching or placement of an IUD. Risk factors for endometritis following delivery include Caesarean section and prolonged rupture of membranes. Chronic endometritis is more common after menopause. The diagnosis may be confirmed by endometrial biopsy. Ultrasound may be useful to verify that there is no retained tissue within the uterus.
Treatment is usually with antibiotics. Recommendations for treatment of endometritis following delivery includes clindamycin with gentamicin. Testing for and treating gonorrhea and chlamydia in those at risk is also recommended. Chronic disease may be treated with doxycycline. Outcomes with treatment are generally good.
Rates of endometritis are about 2% following vaginal delivery, 10% following scheduled C-section, and 30% with rupture of membranes before C-section if preventive antibiotics are not used. The term "endomyometritis" may be used when inflammation of the endometrium and the myometrium is present. The condition is also relatively common in other animals such as cows.
Symptoms
Symptoms may include fever, lower abdominal pain, and abnormal vaginal bleeding or discharge.
Types
Acute endometritis
Acute endometritis is characterized by infection. The organisms most often isolated are believed to be because of compromised abortions, delivery, medical instrumentation, and retention of placental fragments. There is not enough evidence for the use of prophylactic antibiotics to prevent endometritis afte |
https://en.wikipedia.org/wiki/Klee%27s%20measure%20problem | In computational geometry, Klee's measure problem is the problem of determining how efficiently the measure of a union of (multidimensional) rectangular ranges can be computed. Here, a d-dimensional rectangular range is defined to be a Cartesian product of d intervals of real numbers, which is a subset of Rd.
The problem is named after Victor Klee, who gave an algorithm for computing the length of a union of intervals (the case d = 1) which was later shown to be optimally efficient in the sense of computational complexity theory. The computational complexity of computing the area of a union of 2-dimensional rectangular ranges is now also known, but the case d ≥ 3 remains an open problem.
History and algorithms
In 1977, Victor Klee considered the following problem: given a collection of n intervals in the real line, compute the length of their union. He then presented an algorithm to solve this problem with computational complexity (or "running time") — see Big O notation for the meaning of this statement. This algorithm, based on sorting the intervals, was later shown by Michael Fredman and Bruce Weide (1978) to be optimal.
Later in 1977, Jon Bentley considered a 2-dimensional analogue of this problem: given a collection of n rectangles, find the area of their union. He also obtained a complexity algorithm, now known as Bentley's algorithm, based on reducing the problem to n 1-dimensional problems: this is done by sweeping a vertical line across the area. Using this method, the area of the union can be computed without explicitly constructing the union itself. Bentley's algorithm is now also known to be optimal (in the 2-dimensional case), and is used in computer graphics, among other areas.
These two problems are the 1- and 2-dimensional cases of a more general question: given a collection of n d-dimensional rectangular ranges, compute the measure of their union. This general problem is Klee's measure problem.
When generalized to the d-dimensional case, B |
https://en.wikipedia.org/wiki/Author%20citation%20%28zoology%29 | In zoological nomenclature, author citation refers to listing the person (or team) who first makes a scientific name of a taxon available. This is done in scientific work while fulfilling the formal requirements under the International Code of Zoological Nomenclature ("the Code"). According to Article 51.1 of the Code, "The name of the author does not form part of the name of a taxon and its citation is optional, although customary and often advisable." However, recommendation 51A suggests, "The original author and date of a name should be cited at least once in each work dealing with the taxon denoted by that name. This is especially important and has a unique character between homonyms and in identifying species-group names which are not in their native combinations". For the sake of information retrieval, the author citation and year appended to the scientific name, e.g. genus-species-author-year, genus-author-year, family-author-year, etc., is often considered a "de-facto" unique identifier, although this usage may often be imperfect.
Rank matters
The Code recognizes three groups of names, according to rank:
family-group names at the ranks of superfamily, family, subfamily, tribe, subtribe (any rank below superfamily and above genus).
genus-group names at the ranks of genus and subgenus.
species-group names at the ranks of species and subspecies.
Within each group, the same authorship applies regardless of the taxon level to which the name (with, in the case of a family-group name, the appropriate ending) is applied. For example the taxa that the red admiral butterfly can be assigned to:
Family: Nymphalidae Swainson, 1827
Subfamily: Nymphalinae Swainson, 1827
Tribe: Nymphalini Swainson, 1827
Genus: Vanessa Fabricius, 1807
Subgenus: Vanessa (Vanessa) Fabricius, 1807
Species: Vanessa atalanta (Linnaeus, 1758)
Subspecies: Vanessa atalanta atalanta (Linnaeus, 1758)
The parentheses around the author citation indicate that this was not the original taxono |
https://en.wikipedia.org/wiki/Dog-tooth | In architecture, a dog-tooth or dogtooth pattern is an ornament found in the mouldings of medieval work of the commencement of the 12th century, which is thought to have been introduced by the Crusaders. The earliest example is found in the hall at Rabbath Ammon in Moab in Jordan (c. 614) built by the Sassanians, where it decorates the arch moulding of the blind arcades and the string courses. The pattern consists of four flower petals forming a square or diamond shape with central elements. The petals have the form of the pointed conical canine tooth, eye tooth or cuspid.
In the apse of a church at Murano, near Venice, it is similarly employed. In the 12th and 13th centuries it was further elaborated with carving, losing therefore its primitive form, but constituting a most beautiful decorative feature. In Elgin Cathedral in Scotland, the dogtooth ornament in the archivolt becomes a four-lobed leaf, and in Stone church in Kent, a much more enriched type of flower. The term has been supposed to originate in a resemblance to the dog tooth violet, but the original idea of a projecting tooth is a sufficient explanation.
See also
Ball flower
Dentil, also means "tooth", but under cornices |
https://en.wikipedia.org/wiki/Author%20citation%20%28botany%29 | In botanical nomenclature, author citation is the way of citing the person or group of people who validly published a botanical name, i.e. who first published the name while fulfilling the formal requirements as specified by the International Code of Nomenclature for algae, fungi, and plants (ICN). In cases where a species is no longer in its original generic placement (i.e. a new combination of genus and specific epithet), both the authority for the original genus placement and that for the new combination are given (the former in parentheses).
In botany, it is customary (though not obligatory) to abbreviate author names according to a recognised list of standard abbreviations.
There are differences between the botanical code and the normal practice in zoology. In zoology, the publication year is given following the author names and the authorship of a new combination is normally omitted. A small number of more specialized practices also vary between the recommendations of the botanical and zoological codes.
Introduction
In biological works, particularly those dealing with taxonomy and nomenclature but also in ecological surveys, it has long been the custom that full citations to the place where a scientific name was published are omitted, but a short-hand is used to cite the author of the name, at least the first time this is mentioned. The author name is frequently not sufficient information, but can help to resolve some difficulties. Problems include:
The name of a taxon being referred to is ambiguous, as in the case of homonyms such as Ficus L., the fig tree genus, vs. Ficus Röding, 1798, a genus of molluscs.
The publication of the name may be in a little-known journal or book. The author name may sometimes help to resolve this.
The name may not have been validly published, but the supposed author name may be helpful to locate the publication or manuscript in which it was listed.
Rules and recommendations for author citations in botany are covered by Ar |
https://en.wikipedia.org/wiki/Network%20Access%20Identifier | In computer networking, the Network Access Identifier (NAI) is a standard way of identifying users who request access to a network. The standard syntax is "user@realm". Sample NAIs include (from RFC 4282):
bob
joe@example.com
fred@foo-9.example.com
fred.smith@example.com
fred_smith@example.com
fred$@example.com
fred=?#$&*+-/^smith@example.com
eng.example.net!nancy@example.net
eng%nancy@example.net
@privatecorp.example.net
\(user\)@example.net
alice@xn--tmonesimerkki-bfbb.example.net
Network Access Identifiers were originally defined in RFC 2486, which was superseded by RFC 4282, which has been superseded by RFC 7542. The latter RFC is the current standard for the NAI. NAIs are commonly found as user identifiers in the RADIUS and Diameter network access protocols and the EAP authentication protocol.
The Network Access Identifier (NAI) is the user identity submitted by the client during network access authentication.
It is used mainly for two purposes:
The NAI is used when roaming, to identify the user.
To assist in the routing of the authentication request to the user's authentication server.
See also
Diameter
EAP
RADIUS
Request for Comments
External links
Internet Standards |
https://en.wikipedia.org/wiki/Bioelectromagnetics | Bioelectromagnetics, also known as bioelectromagnetism, is the study of the interaction between electromagnetic fields and biological entities. Areas of study include electromagnetic fields produced by living cells, tissues or organisms, the effects of man-made sources of electromagnetic fields like mobile phones, and the application of electromagnetic radiation toward therapies for the treatment of various conditions.
Biological phenomena
Bioelectromagnetism is studied primarily through the techniques of electrophysiology. In the late eighteenth century, the Italian physician and physicist Luigi Galvani first recorded the phenomenon while dissecting a frog at a table where he had been conducting experiments with static electricity. Galvani coined the term animal electricity to describe the phenomenon, while contemporaries labeled it galvanism. Galvani and contemporaries regarded muscle activation as resulting from an electrical fluid or substance in the nerves. Short-lived electrical events called action potentials occur in several types of animal cells which are called excitable cells, a category of cell include neurons, muscle cells, and endocrine cells, as well as in some plant cells. These action potentials are used to facilitate inter-cellular communication and activate intracellular processes. The physiological phenomena of action potentials are possible because voltage-gated ion channels allow the resting potential caused by electrochemical gradient on either side of a cell membrane to resolve..
Several animals are suspected to have the ability to sense electromagnetic fields; for example, several aquatic animals have structures potentially capable of sensing changes in voltage caused by a changing magnetic field, while migratory birds are thought to use magnetoreception in navigation.
Bioeffects of electromagnetic radiation
Most of the molecules in the human body interact weakly with electromagnetic fields in the radio frequency or extremely low frequen |
https://en.wikipedia.org/wiki/Parallelizable%20manifold | In mathematics, a differentiable manifold of dimension n is called parallelizable if there exist smooth vector fields
on the manifold, such that at every point of the tangent vectors
provide a basis of the tangent space at . Equivalently, the tangent bundle is a trivial bundle, so that the associated principal bundle of linear frames has a global section on
A particular choice of such a basis of vector fields on is called a parallelization (or an absolute parallelism) of .
Examples
An example with is the circle: we can take V1 to be the unit tangent vector field, say pointing in the anti-clockwise direction. The torus of dimension is also parallelizable, as can be seen by expressing it as a cartesian product of circles. For example, take and construct a torus from a square of graph paper with opposite edges glued together, to get an idea of the two tangent directions at each point. More generally, every Lie group G is parallelizable, since a basis for the tangent space at the identity element can be moved around by the action of the translation group of G on G (every translation is a diffeomorphism and therefore these translations induce linear isomorphisms between tangent spaces of points in G).
A classical problem was to determine which of the spheres Sn are parallelizable. The zero-dimensional case S0 is trivially parallelizable. The case S1 is the circle, which is parallelizable as has already been explained. The hairy ball theorem shows that S2 is not parallelizable. However S3 is parallelizable, since it is the Lie group SU(2). The only other parallelizable sphere is S7; this was proved in 1958, by Friedrich Hirzebruch, Michel Kervaire, and by Raoul Bott and John Milnor, in independent work. The parallelizable spheres correspond precisely to elements of unit norm in the normed division algebras of the real numbers, complex numbers, quaternions, and octonions, which allows one to construct a parallelism for each. Proving that other spheres are not |
https://en.wikipedia.org/wiki/Societ%C3%A0%20Entomologica%20Italiana | La Società Entomologica Italiana, the Italian Entomological Society, is Italy’s foremost society devoted to the study of insects. The society is famous for promoting applied entomology and many of its past members have saved millions from deadly diseases such as malaria.
History
The society was founded on 31 October 1869, near the "Regio Museo di Storia Naturale", the Royal Natural History Museum (effectively "Museo zoologico de La Specola") in Florence.
The Society had been promoted almost two years before by a group of Italian and other scientists from various institutions across Italy. On 1 January 1868, 21 members of a committee called "Comitato dei Promotori della Società Entomologica Italiana" signed a "manifesto" letter. Coordinated by Alexander Enrico Haliday were four Academic Associates. Emilio Cornalia, then director of del Museo civico di Storia naturale di Milano, the author of works of applied entomology, such as "La Monografia del bombice del gelso" published in 1856; Giovanni Passerini, university professor of Botany at the Università di Parma; Paolo Savi, director of the "Museo zoologico dell'Università di Pisa", and author of "Ornitologia Toscana", Tuscany Birds (1827–1831), who had also promoted the first congress of Italian scientists, Primo Congresso degli Scienziati Italiani at Pisa in 1839 an author of notes on breeding Samia cynthia, an alternative silk producer of optimal quality "shantung" and Achille Costa, holder of the first chair of Entomology and director of Museo zoologico dell'Università di Napoli. Adolfo Targioni Tozzetti and Pietro Stefanelli are also listed as one of the Comitato. Fernandino Maria Piccioli was an editor.
The founding of the society was a part of the Risorgimento. In 1922 it moved to Genoa, to Museo Civico di Storia Naturale di Genova, where it is based until now.
La Società Entomologica Italiana collaborates with Unione Zoologica Italiana, the Italian Zoological Society in maintaining a website listing |
https://en.wikipedia.org/wiki/Neurogenic%20inflammation | Neurogenic inflammation is inflammation arising from the local release by afferent neurons of inflammatory mediators such as Substance P, Calcitonin Gene-Related Peptide (CGRP), neurokinin A (NKA), and endothelin-3 (ET-3). In such neurons, release of these pro-inflammatory mediators is thought to be triggered by the activation of ion channels that are the principal detectors of noxious environmental stimuli. In particular, the heat/capsaicin receptor TRPV1 and the irritant/wasabi receptor TRPA1. TRPA1 channels stimulated by lipopolysaccharide (LPS) may also cause acute neurogenic inflammation.
Once released, these neuropeptides induce the release of histamine from adjacent mast cells. In turn, histamine evokes the release of substance P and calcitonin gene-related peptide; thus, a bidirectional link between histamine and neuropeptides in neurogenic inflammation is established.
Neurogenic inflammation appears to play an important role in the pathogenesis of numerous diseases including migraine, psoriasis, asthma, vasomotor rhinitis, fibromyalgia, eczema, rosacea, dystonia, and multiple chemical sensitivity.
In migraine, stimulation of the trigeminal nerve causes neurogenic inflammation via release of neuropeptides including Substance P, nitric oxide, vasoactive intestinal polypeptide, 5-HT, Neurokinin A and CGRP. leading to a "sterile neurogenic inflammation."
Prevention
Magnesium deficiency causes neurogenic inflammation in a rat model. Researchers have theorized that since substance P which appears at day five of induced magnesium deficiency, is known to stimulate in turn the production of other inflammatory cytokines including IL-1, Interleukin 6 (IL-6), and TNF-alpha (TNFα), which begin a sharp rise at day 12, substance P is a key in the path from magnesium deficiency to the subsequent cascade of neuro-inflammation. In a later study, researchers provided rats dietary levels of magnesium that were reduced but still within the range of dietary intake found i |
https://en.wikipedia.org/wiki/Ingress%20cancellation | Ingress cancellation is a method for removing narrowband noise from an electromagnetic signal using a digital filter. This type of filter is used on hybrid fiber-coaxial broadband networks.
If a carrier appears in the middle of the upstream data signal, ingress cancellation can remove the interfering carrier without causing packet loss.
Ingress cancellation also removes one or more carriers that are higher in amplitude than the data signal. Ingress cancellation eventually will break if the in-channel ingress gets too high. |
https://en.wikipedia.org/wiki/Stunted%20projective%20space | In mathematics, a stunted projective space is a construction on a projective space of importance in homotopy theory, introduced by . Part of a conventional projective space is collapsed down to a point.
More concretely, in a real projective space, complex projective space or quaternionic projective space
KPn,
where K stands for the real numbers, complex numbers or quaternions, one can find (in many ways) copies of
KPm,
where m < n. The corresponding stunted projective space is then
KPn,m = KPn/KPm,
where the notation implies that the KPm has been identified to a point. This makes a topological space that is no longer a manifold. The importance of this construction was realised when it was shown that real stunted projective spaces arose as Spanier–Whitehead duals of spaces of Ioan James, so-called quasi-projective spaces, constructed from Stiefel manifolds. Their properties were therefore linked to the construction of frame fields on spheres.
In this way the vector fields on spheres question was reduced to a question on stunted projective spaces: for RPn,m, is there a degree one mapping on the 'next cell up' (of the first dimension not collapsed in the 'stunting') that extends to the whole space? Frank Adams showed that this could not happen, completing the proof.
In later developments spaces KP∞,m and stunted lens spaces have also been used. |
https://en.wikipedia.org/wiki/Spanier%E2%80%93Whitehead%20duality | In mathematics, Spanier–Whitehead duality is a duality theory in homotopy theory, based on a geometrical idea that a topological space X may be considered as dual to its complement in the n-sphere, where n is large enough. Its origins lie in Alexander duality theory, in homology theory, concerning complements in manifolds. The theory is also referred to as S-duality, but this can now cause possible confusion with the S-duality of string theory. It is named for Edwin Spanier and J. H. C. Whitehead, who developed it in papers from 1955.
The basic point is that sphere complements determine the homology, but not the homotopy type, in general. What is determined, however, is the stable homotopy type, which was conceived as a first approximation to homotopy type. Thus Spanier–Whitehead duality fits into stable homotopy theory.
Statement
Let X be a compact neighborhood retract in . Then and are dual objects in the category of pointed spectra with the smash product as a monoidal structure. Here is the union of and a point, and are reduced and unreduced suspensions respectively.
Taking homology and cohomology with respect to an Eilenberg–MacLane spectrum recovers Alexander duality formally. |
https://en.wikipedia.org/wiki/Hermitian%20function | In mathematical analysis, a Hermitian function is a complex function with the property that its complex conjugate is equal to the original function with the variable changed in sign:
(where the indicates the complex conjugate) for all in the domain of . In physics, this property is referred to as PT symmetry.
This definition extends also to functions of two or more variables, e.g., in the case that is a function of two variables it is Hermitian if
for all pairs in the domain of .
From this definition it follows immediately that: is a Hermitian function if and only if
the real part of is an even function,
the imaginary part of is an odd function.
Motivation
Hermitian functions appear frequently in mathematics, physics, and signal processing. For example, the following two statements follow from basic properties of the Fourier transform:
The function is real-valued if and only if the Fourier transform of is Hermitian.
The function is Hermitian if and only if the Fourier transform of is real-valued.
Since the Fourier transform of a real signal is guaranteed to be Hermitian, it can be compressed using the Hermitian even/odd symmetry. This, for example, allows the discrete Fourier transform of a signal (which is in general complex) to be stored in the same space as the original real signal.
If f is Hermitian, then .
Where the is cross-correlation, and is convolution.
If both f and g are Hermitian, then .
See also
Types of functions
Calculus |
https://en.wikipedia.org/wiki/Alexander%20duality | In mathematics, Alexander duality refers to a duality theory initiated by a result of J. W. Alexander in 1915, and subsequently further developed, particularly by Pavel Alexandrov and Lev Pontryagin. It applies to the homology theory properties of the complement of a subspace X in Euclidean space, a sphere, or other manifold. It is generalized by Spanier–Whitehead duality.
General statement for spheres
Let be a compact, locally contractible subspace of the sphere of dimension n. Let be the complement of in . Then if stands for reduced homology or reduced cohomology, with coefficients in a given abelian group, there is an isomorphism
for all . Note that we can drop local contractibility as part of the hypothesis if we use Čech cohomology, which is designed to deal with local pathologies.
Applications
This is useful for computing the cohomology of knot and link complements in . Recall that a knot is an embedding and a link is a disjoint union of knots, such as the Borromean rings. Then, if we write the link/knot as , we have
,
giving a method for computing the cohomology groups. Then, it is possible to differentiate between different links using the Massey products.
For example, for the Borromean rings , the homology groups are
Alexander duality for constructible sheaves
For smooth manifolds, Alexander duality is a formal consequence of Verdier duality for sheaves of abelian groups. More precisely, if we let denote a smooth manifold and we let be a closed subspace (such as a subspace representing a cycle, or a submanifold) represented by the inclusion , and if is a field, then if is a sheaf of -vector spaces we have the following isomorphism
,
where the cohomology group on the left is compactly supported cohomology. We can unpack this statement further to get a better understanding of what it means. First, if is the constant sheaf and is a smooth submanifold, then we get
,
where the cohomology group on the right is local cohomology with support in . |
https://en.wikipedia.org/wiki/Landauer%27s%20principle | Landauer's principle is a physical principle pertaining to the lower theoretical limit of energy consumption of computation. It holds that an irreversible change in information stored in a computer, such as merging two computational paths, dissipates a minimum amount of heat to its surroundings.
The principle was first proposed by Rolf Landauer in 1961.
Statement
Landauer's principle states that the minimum energy needed to erase one bit of information is proportional to the temperature at which the system is operating. More specifically, the energy needed for this computational task is given by
where is the Boltzmann constant. At room temperature, the Landauer limit represents an energy of approximately . Modern computers use about a billion times as much energy per operation.
History
Rolf Landauer first proposed the principle in 1961 while working at IBM. He justified and stated important limits to an earlier conjecture by John von Neumann. For this reason, it is sometimes referred to as being simply the Landauer bound or Landauer limit.
In 2008 and 2009, researchers showed that Landauer's principle can be derived from the second law of thermodynamics and the entropy change associated with information gain, developing the thermodynamics of quantum and classical feedback-controlled systems.
In 2011, the principle was generalized to show that while information erasure requires an increase in entropy, this increase could theoretically occur at no energy cost. Instead, the cost can be taken in another conserved quantity, such as angular momentum.
In a 2012 article published in Nature, a team of physicists from the École normale supérieure de Lyon, University of Augsburg and the University of Kaiserslautern described that for the first time they have measured the tiny amount of heat released when an individual bit of data is erased.
In 2014, physical experiments tested Landauer's principle and confirmed its predictions.
In 2016, researchers used a laser probe |
https://en.wikipedia.org/wiki/Sarcopenia | Sarcopenia is a type of muscle loss (muscle atrophy) that occurs with aging and/or immobility. It is characterized by the degenerative loss of skeletal muscle mass, quality, and strength. The rate of muscle loss is dependent on exercise level, co-morbidities, nutrition and other factors. The muscle loss is related to changes in muscle synthesis signalling pathways. It is distinct from cachexia, in which muscle is degraded through cytokine-mediated degradation, although both conditions may co-exist. Sarcopenia is considered a component of frailty syndrome. Sarcopenia can lead to reduced quality of life, falls, fracture, and disability.
Sarcopenia is a factor in changing body composition associated with aging populations; and certain muscle regions are expected to be affected first, specifically the anterior thigh and abdominal muscles. In population studies, body mass index (BMI) is seen to decrease in aging populations while bioelectrical impedance analysis (BIA) shows body fat proportion rising.
The term sarcopenia is from Greek σάρξ sarx, "flesh" and πενία penia, "poverty". This was first proposed by Rosenberg in 1989, who wrote that "there may be no single feature of age-related decline that could more dramatically affect ambulation, mobility, calorie intake, and overall nutrient intake and status, independence, breathing, etc".
Signs and symptoms
The hallmark sign of sarcopenia is loss of lean muscle mass, or muscle atrophy. The change in body composition may be difficult to detect due to obesity, changes in fat mass, or edema. Changes in weight, limb or waist circumference are not reliable indicators of muscle mass changes. Sarcopenia may also cause reduced strength, functional decline and increased risk of falling. Sarcopenia may also have no symptoms until it is severe and is often unrecognized. Research has shown, however, that hypertrophy may occur in the upper parts of the body to compensate for this loss of lean muscle mass Therefore, one early indica |
https://en.wikipedia.org/wiki/Trade-weighted%20effective%20exchange%20rate%20index | The trade-weighted effective exchange rate index, a common form of the effective exchange rate index, is a multilateral exchange rate index. It is compiled as a weighted average of exchange rates of home versus foreign currencies, with the weight for each foreign country equal to its share in trade. Depending on the purpose for which it is used, it can be export-weighted, import-weighted, or total-external trade weighted.
The trade-weighted effective exchange rate index is an economic indicator for comparing the exchange rate of a country against those of their major trading partners. By design, movements in the currencies of those trading partners with a greater share in an economy's exports and imports will have a greater effect on the effective exchange rate. In a multilateral, highly globalized, world, the effective exchange rate index is much more useful than a bilateral exchange rate, such as that between the Australian dollar and the United States dollar, for assessing changes in the competitiveness due to exchange rate movements.
Generally, the weighting method is geometric weighting rather than arithmetic weighting. Refer to weighted geometric mean. The use of trade weights in a globalized economy is potentially misleading, because the amount of value added content in exports destined for a country may deviate significantly from the gross value of exports shipped to that country. See the entry under effective exchange rate index for an alternative approach to compiling an effective exchange rate index.
The interpretation of the effective exchange rate is that if the index rises, other things being equal, the purchasing power of that currency also rises (the currency strengthened against those of the country's or area's trading partners). That will reduce the cost of imports but will undermine the competitiveness of exports. Other things refer, in particular, to the relative inflation rates of the economy as compared to the inflation rates of its trad |
https://en.wikipedia.org/wiki/Ant%20Attack | Ant Attack is a ZX Spectrum computer game by Sandy White, published by Quicksilva in 1983. It was converted to the Commodore 64 in 1984.
While Zaxxon and Q*bert previously used isometric projection, Ant Attack added an extra degree of freedom (ability to go up and down instead of just north, south, east and west), and it may be the first isometric game for personal computers. The same type of isometric projection was used in Sandy White's later Zombie Zombie. It was also one of the first games to allow players to choose their gender.
Gameplay
The player chooses whether to control the character of "Girl" or "Boy", who then enters the walled city of Antescher to rescue the other, who has been captured and immobilised somewhere in the city.
The city is inhabited by giant ants which chase and attempt to bite the player. The player can defend themselves by throwing grenades at the ants, but these can also harm the humans. Once the hostage is rescued, the two must escape the city. The game then starts again with the hostage located in a different, harder-to-reach part of the city.
Development
Almost all of the game code was written by hand on paper using assembler mnemonics, then manually assembled, with the resulting hexadecimal digits typed sequentially into an external EEPROM emulator device (aka SoftROM or "softie") attached to a host Spectrum. Similarly, the character graphics and other custom sprites were all hand-drawn on squared paper and manually converted to strings of hex data. Additionally, some minor add-on routines such as high score registration were added on to the core game using regular Sinclair BASIC.
The game's setting of "Antescher" is a reference to the artist M. C. Escher.
Reception
Ant Attack was well received by gaming press. The game was nominated in the 1983 Golden Joystick Awards for Best Original Game of the Year, eventually coming second to Ah Diddums. The ZX Spectrum version was rated number 14 in the Your Sinclair'''s Official Top |
https://en.wikipedia.org/wiki/Sacral%20plexus | In human anatomy, the sacral plexus is a nerve plexus which provides motor and sensory nerves for the posterior thigh, most of the lower leg and foot, and part of the pelvis. It is part of the lumbosacral plexus and emerges from the lumbar vertebrae and sacral vertebrae (L4-S4). A sacral plexopathy is a disorder affecting the nerves of the sacral plexus, usually caused by trauma, nerve compression, vascular disease, or infection. Symptoms may include pain, loss of motor control, and sensory deficits.
Structure
The sacral plexus is formed by:
the lumbosacral trunk
the anterior division of the first sacral nerve
portions of the anterior divisions of the second and third sacral nerves
The nerves forming the sacral plexus converge toward the lower part of the greater sciatic foramen, and unite to form a flattened band, from the anterior and posterior surfaces of which several branches arise.
The band itself is continued as the sciatic nerve, which splits on the back of the thigh into the tibial nerve and common fibular nerve; these two nerves sometimes arise separately from the plexus, and in all cases their independence can be shown by dissection. Often, the sacral plexus and the lumbar plexus are considered to be one large nerve plexus, the lumbosacral plexus. The lumbosacral trunk connects the two plexuses.
Relations
The sacral plexus lies on the back of the pelvis in front of the piriformis muscle and the pelvic fascia. In front of it are the internal iliac artery, internal iliac vein, the ureter, and the sigmoid colon. The superior gluteal artery and vein run between the lumbosacral trunk and the first sacral nerve, and the inferior gluteal artery and vein between the second and third sacral nerves.
Nerves formed
All the nerves entering the plexus, with the exception of the third sacral, split into ventral and dorsal divisions, and the nerves arising from these are as follows of the table below:
Additional images
See also
Cervical plexus
Brachial plexu |
https://en.wikipedia.org/wiki/Defence%20Information%20Infrastructure | Defence Information Infrastructure (DII) is a secure military network owned by the United Kingdom's Ministry of Defence MOD. It is used by all branches of the armed forces, including the Royal Navy, British Army and Royal Air Force as well as MOD civil servants. It reaches to deployed bases and ships at sea, but not to aircraft in flight.
The partnership developing DII is called the Atlas Consortium and is made up of DXC Technology (formerly EDS), Fujitsu, Airbus Defence and Space (formerly EADS Defence & Security) and CGI (formerly Logica).
Starting in May 2016, MOD users of DII begin to migrate to the New Style of IT within the defence to be known as MODNET; again supported by ATLAS.
Overview
DII supports 2,000 MOD sites with some 150,000 terminals (desktops and laptops) and 300,000 user accounts. It is designed to offer a high level of resilience, flexibility, and security in the provision of connectivity from ‘business space to battlespace’ in MOD offices in the UK, bases overseas, at sea, and on the front line. It aims to rationalise and improve IT provision for the defence sector in the 21st century; involving a major culture change for MOD users and their ways of working through a structure of shared working areas with controlled security and access. It should provide a records management system and search facility together with a range of office services. It hosts several hundred COTS (commercial off-the-shelf) and bespoke MOD applications from a range of suppliers judged to meet the required security standards. The network handles alphanumeric data, graphics, and video. The system carries information from Restricted to above-Secret levels, but users are able to see only the data and applications for which they are authorised.
Incremental approach
In order to de-risk the programme Atlas and the MOD took an incremental approach to the development and implementation of DII, with a separate contract for each increment. The extended timeline allowed t |
https://en.wikipedia.org/wiki/Senckenberg%20German%20Entomological%20Institute | The Senckenberg German Entomological Institute (, SDEI or DEI) is a German entomological research institute devoted to the study of insects. Founded in 1886, the institute has an extraordinary insect collection and a world-class entomological library. Since 2009, the SDEI has been part of the Senckenberg Nature Research Society.
Insect collections
The department of Phylogenetic Systematics and Taxonomy of Insects maintains about 3 million pinned insects and uncounted specimens in the wet collection, among others the collections of:
Rudolf von Bennigsen (1824-1902)
Karl Bleyl (1908-1995)
Carl Julius Bernhard Börner (1880-1953)
Peter Friedrich Bouché (1784-1856)
Gustav Breddin (1864-1909)
Adolf Willy Lothar Dieckmann (1920-1990)
Karl Friedrich Ermisch (1898-1970)
Karl Flach (1856-1920)
Gerrit Friese (1931-1990)
Johann Georg Haag-Rutenberg (1830-1880)
Lucas Friedrich Julius Dominikus von Heyden (1838-1915)
Walther Hermann Richard Horn (1871-1939)
Carl Friedrich Ketel (1861-1906)
Hermann Kläger (1847-1923)
Hermann Albert Friedrich Köller (1885-1968)
Wilhelm Koltze (1839-1914)
Ernst Gustav Kraatz (1831-1909)
Friedrich Wilhelm Konow (1842-1908)
Karl Friedrich Lange (1844-1913)
Otto Leonhard (1853-1929)
Karl Wilhelm Letzner (1812-1889)
Bernhardt Lichtwardt (1857-1943)
Walter Liebmann (1885-1974)
Gustav Adolf Lohse (1910-1994)
Axel Leonard Melander (1878-1962)
Julius Melzer (1878-1934)
Wilhelm Mink (1807-1883)
Karl-Heinz Mohr (1925-1989)
Julius Neresheimer (1880-1943)
Heinrich von Oettingen (1878-1956)
Lorenz Oldenberg (1863-1931)
Carl Robert Osten-Sacken (1828-1906)
Gustav Paganetti-Hummler (1871-1949)
Paul Pape (1859-1933)
Helmuth Patzak (1927-1988)
Ernst Pietsch (1872-1930)
Karl Ritter (1909-1998)
William Henry Rolph (1847-1883)
Arthur Leopold Albert Maria Rottenberg (1843-1875)
Max Saalmüller (1832-1890)
Johann Christian Rudolf Sachse (1802-1891)
Hans Sauter (1871-1948)
Ludwig Wilhelm Schaufuss (1833-1890)
Karl Gotthilf Schenkling (1835-1911)
Sigmund Schenkling (1865 |
https://en.wikipedia.org/wiki/Common%20fibular%20nerve | The common fibular nerve (also known as the common peroneal nerve, external popliteal nerve, or lateral popliteal nerve) is a nerve in the lower leg that provides sensation over the posterolateral part of the leg and the knee joint. It divides at the knee into two terminal branches: the superficial fibular nerve and deep fibular nerve, which innervate the muscles of the lateral and anterior compartments of the leg respectively. When the common fibular nerve is damaged or compressed, foot drop can ensue.
Structure
The common fibular nerve is the smaller terminal branch of the sciatic nerve. The common fibular nerve has root values of L4, L5, S1, and S2. It arises from the superior angle of the popliteal fossa and extends to the lateral angle of the popliteal fossa, along the medial border of the biceps femoris. It then winds around the neck of the fibula to pierce the fibularis longus and divides into terminal branches of the superficial fibular nerve and the deep fibular nerve. Before its division, the common fibular nerve gives off several branches in the popliteal fossa.
Cutaneous branches
Lateral sural cutaneous nerve (lateral cutaneous nerve of calf) - supplies the skin of the upper two-thirds of the lateral side of leg.
sural communicating nerve - it runs on the posterolateral aspect of the calf and joins the sural nerve.
Articular branches
Superior lateral genicular nerve - accompanies artery of the same name and lies above the lateral femoral condyle.
Inferior lateral genicular nerve - accompanies artery of the same name and lies just above the head of the fibula.
Recurrent genicular nerve - It arises from the point of division of the common fibular nerve; then ascends anterior to the knee joint together with the anterior recurrent tibial artery to supply the knee joint and the tibialis anterior muscle.
Motor branches
There is only one motor branch that arises directly from the common fibular nerve, the nerve to the short head of the biceps femoris m |
https://en.wikipedia.org/wiki/Mauve%20%28test%20suite%29 | Mauve is a project to provide a free software test suite for the Java class libraries. Mauve is developed by the members of Kaffe, GNU Classpath, GCJ, and other projects. Unlike a similar project, JUnit, Mauve is designed to run on various experimental Java virtual machines, where some features may be still missing. Because of this, Mauve does not discover the testing method by name, as JUnit does. Mauve can also be used to test the user java application, not just the core class library. Mauve is released under GNU General Public License.
Example
The "Hello world" example in Mauve:
// Tags: JDK1.4
public class HelloWorld implements Testlet {
// Test if 3 * 2 = 6
public void test(TestHarness harness) {
harness.check(3 * 2, 6, "Multiplication failed.");
}
}
See also
Technology Compatibility Kit
External links
Mauve homepage
Extreme programming
Software testing |
https://en.wikipedia.org/wiki/Sensory%20threshold | In psychophysics, sensory threshold is the weakest stimulus that an organism can sense. Unless otherwise indicated, it is usually defined as the weakest stimulus that can be detected half the time, for example, as indicated by a point on a probability curve. Methods have been developed to measure thresholds in any of the senses.
Several different sensory thresholds have been defined;
Absolute threshold: the lowest level at which a stimulus can be detected.
Recognition threshold: the level at which a stimulus can not only be detected but also recognized.
Differential threshold: the level at which an increase in a detected stimulus can be perceived.
Terminal threshold: the level beyond which any increase to a stimulus no longer changes the perceived intensity.
History
The first systematic studies to determine sensory thresholds were conducted by Ernst Heinrich Weber, a physiologist and pioneer of experimental psychology at the Leipzig University. His experiments were intended to determine the absolute and difference, or differential, thresholds. Weber was able to define absolute and difference threshold statistically, which led to the establishment of Weber's Law and the concept of just noticeable difference to describe threshold perception of stimuli.
Following Weber's work, Gustav Fechner, a pioneer of psychophysics, studied the relationship between the physical intensity of a stimulus and the psychologically perceived intensity of the stimulus. Comparing the measured intensity of sound waves with the perceived loudness, Fechner concluded that the intensity of a stimulus changes in proportion to the logarithm of the stimulus intensity. His findings would lead to the creation of the decibel scale.
Measuring and testing sensory thresholds
Defining and measuring sensory thresholds requires setting the sensitivity limit such that the perception observations lead to the absolute threshold. The level of sensitivity is usually assumed to be constant in determining th |
https://en.wikipedia.org/wiki/Intercostal%20nerves | The intercostal nerves are part of the somatic nervous system, and arise from the anterior rami of the thoracic spinal nerves from T1 to T11. The intercostal nerves are distributed chiefly to the thoracic pleura and abdominal peritoneum, and differ from the anterior rami of the other spinal nerves in that each pursues an independent course without plexus formation.
The first two nerves supply fibers to the upper limb and thorax; the next four distribute to the walls of the thorax; the lower five supply the walls of the thorax and abdomen. The 7th intercostal nerve ends at the xyphoid process of the sternum. The 10th intercostal nerve terminates at the navel. The 12th (subcostal) thoracic is distributed to the walls of the abdomen and groin. Each of these fibers contains around 1300 axons.
Unlike the nerves from the autonomic nervous system that innervate the visceral pleura of the thoracic cavity, the intercostal nerves arise from the somatic nervous system. This enables them to control the contraction of muscles, as well as provide specific sensory information regarding the skin and parietal pleura. This explains why damage to the internal wall of the thoracic cavity can be felt as a sharp pain localized in the injured region. Damage to the visceral pleura is experienced as an un-localized ache.
The 1st thoracic nerve
The anterior division of the first thoracic nerve divides into two branches. The larger branch leaves the thorax in front of the neck of the first rib, and enters the brachial plexus. The smaller branch, the first intercostal nerve, runs along the first intercostal space, and ends on the front of the chest as the first anterior cutaneous branch of the thorax. Occasionally, this anterior cutaneous branch is missing.
The first intercostal nerve rarely gives off a lateral cutaneous branch; but sometimes sends a small branch to communicate with the intercostobrachial.
From the second thoracic nerve it frequently receives a connecting twig, which asce |
https://en.wikipedia.org/wiki/Call%20super | Call super is a code smell or anti-pattern of some object-oriented programming languages. Call super is a design pattern in which a particular class stipulates that in a derived subclass, the user is required to override a method and call back the overridden function itself at a particular point. The overridden method may be intentionally incomplete, and reliant on the overriding method to augment its functionality in a prescribed manner. However, the fact that the language itself may not be able to enforce all conditions prescribed on this call is what makes this an anti-pattern.
Description
In object-oriented programming, users can inherit the properties and behaviour of a superclass in subclasses. A subclass can override methods of its superclass, substituting its own implementation of the method for the superclass's implementation. Sometimes the overriding method will completely replace the corresponding functionality in the superclass, while in other cases the superclass's method must still be called from the overriding method. Therefore, most programming languages require that an overriding method must explicitly call the overridden method on the superclass for it to be executed.
The call super anti-pattern relies on the users of an interface or framework to derive a subclass from a particular class, override a certain method and require the overridden method to call the original method from the overriding method:
This is often required, since the superclass must perform some setup tasks for the class or framework to work correctly, or since the superclass's main task (which is performed by this method) is only augmented by the subclass.
The anti-pattern is the of calling the parent. There are many examples in real code where the method in the subclass may still want the superclass's functionality, usually where it is only augmenting the parent functionality. If it still has to call the parent class even if it is fully replacing the functionality, the a |
https://en.wikipedia.org/wiki/Drainage%20density | Drainage density is a quantity used to describe physical parameters of a drainage basin. First described by Robert E. Horton, drainage density is defined as the total length of channel in a drainage basin divided by the total area, represented by the following equation:
The quantity represents the average length of channel per unit area of catchment and has units , which is often reduced to .
Drainage density depends upon both climate and physical characteristics of the drainage basin. Soil permeability (infiltration difficulty) and underlying rock type affect the runoff in a watershed; impermeable ground or exposed bedrock will lead to an increase in surface water runoff and therefore to more frequent streams. Rugged regions or those with high relief will also have a higher drainage density than other drainage basins if the other characteristics of the basin are the same.
When determining the total length of streams in a basin, both perennial and ephemeral streams should be considered. If a drainage basin contained only ephemeral streams, the drainage density by the equation above would be calculated to be zero if only the total length of streams was calculated using only perennial streams. Ignoring ephemeral streams in the calculations does not consider the behavior of the basin during flood events and is therefore not completely representative of the drainage characteristics of the basin.
Drainage density is indicative of infiltration and permeability of a drainage basin, as well as relating to the shape of the hydrograph. Drainage density depends upon both climate and physical characteristics of the drainage basin.
High drainage densities also mean a high bifurcation ratio.
Inverse of drainage density as a physical quantity
Drainage density can be used to approximate the average length of overland flow in a catchment. Horton (1945) used the following equation to describe the average length of overland flow as a function of drainage density:
Where is th |
https://en.wikipedia.org/wiki/Institut%20d%27Astrophysique%20de%20Paris | The Institut d'Astrophysique de Paris (translated: Paris Institute of Astrophysics) is a research institute in Paris, France. The Institute is part of the Sorbonne University and is associated with the CNRS Centre national de la recherche scientifique. It is located at 98bis, Boulevard Arago Il in the 14th arrondissement of Paris, adjacent to the Paris Observatory.
History
The IAP was created in 1936 by the French ministry of education under Jean Zay, initially for the purpose of processing data received from the Observatory of Haute-Provence, which was created at the same time. Construction of the building started on 6 January 1938. On 15 June 1939, Henri Mineur became the institute's first director. IAP scientists were at first located in Paris Observatory, then in the École normale supérieure de Paris before arriving in the current building in 1944 which was finally completed in 1952.
Current research
The IAP includes 160 researchers, engineers, technicians, and administrators and regularly welcomes many visitors and students.
The main areas of research at the IAP are:
General relativity and cosmology
Cosmological structure formation
High-energy astrophysics
Origin and evolution of galaxies
Stellar structure
Exoplanets
The IAP is one of five laboratories of AERA, the European association for research in astronomy. The laboratory is situated at the interface between two disciplines, astrophysics and theoretical physics. The International Astronomical Union has its seat at the IAP.
Directors
1936-1954 : Henri Mineur
1954-1960 : André Danjon
1960-1971 : André Lallemand
1972-1977 : Jean-Claude Pecker
1978-1989 : Jean Audouze
1990-1998 : Alain Omont
1998-2004 : Bernard Fort
2005-2013 : Laurent Vigroux
Since 2014 : Francis Bernardeau |
https://en.wikipedia.org/wiki/Hesiod%20%28name%20service%29 | In computing, the Hesiod name service originated in Project Athena (1983–1991). It uses DNS functionality to provide access to databases of information that change infrequently. In Unix environments it often serves to distribute information kept in the , , and files, among others.
Frequently an LDAP server is used to distribute the same kind of information that Hesiod does. However, because Hesiod can leverage existing DNS servers, deploying it to a network is fairly easy.
In a Unix-like system users usually have a line in the file for each local user like:
foo:x:100:10:Foo Bar:/home/foo:/bin/sh
This line is composed of seven colon-separated fields which hold the following data:
user login name (string);
password hash or "x" if shadow password file is in use (string);
user id (unsigned integer);
user's primary group id (unsigned integer);
Gecos field (four comma separated fields, string);
user home directory (string);
user login shell (string).
This system works fine for a small number of users on a small number of machines. But when more users start using more machines, having this information managed in one location becomes critical. This is where Hesiod enters.
Instead of having this information stored on every machine, Hesiod stores it in records on your DNS server. Then each client can query the DNS server for this information instead of looking for it locally. In BIND the records for the above user might look something like:
foo.passwd.ns.example.net HS TXT "foo:x:100:10:Foo Bar:/home/foo:/bin/sh"
100.passwd.ns.example.net HS TXT "foo:x:100:10:Foo Bar:/home/foo:/bin/sh"
100.uid.ns.example.net HS TXT "foo:x:100:10:Foo Bar:/home/foo:/bin/sh"
There are three records because the system needs to be able to access the information in different ways. The first line supports looking up the user by their login name and the second two allow it to look up information by the user's uid. Note the use of the HS class instead of IN as migh |
https://en.wikipedia.org/wiki/Nuclear%20reactor%20core | A nuclear reactor core is the portion of a nuclear reactor containing the nuclear fuel components where the nuclear reactions take place and the heat is generated. Typically, the fuel will be low-enriched uranium contained in thousands of individual fuel pins. The core also contains structural components, the means to both moderate the neutrons and control the reaction, and the means to transfer the heat from the fuel to where it is required, outside the core.
Water-moderated reactors
Inside the core of a typical pressurized water reactor or boiling water reactor are fuel rods with a diameter of a large gel-type ink pen, each about 4 m long, which are grouped by the hundreds in bundles called "fuel assemblies". Inside each fuel rod, pellets of uranium, or more commonly uranium oxide, are stacked end to end. Also inside the core are control rods, filled with pellets of substances like boron or hafnium or cadmium that readily capture neutrons. When the control rods are lowered into the core, they absorb neutrons, which thus cannot take part in the chain reaction. Conversely, when the control rods are lifted out of the way, more neutrons strike the fissile uranium-235 (U-235) or plutonium-239 (Pu-239) nuclei in nearby fuel rods, and the chain reaction intensifies. The core shroud, also located inside of the reactor, directs the water flow to cool the nuclear reactions inside of the core. The heat of the fission reaction is removed by the water, which also acts to moderate the neutron reactions.
Graphite-moderated reactors
There are also graphite moderated reactors in use.
One type uses solid nuclear graphite for the neutron moderator and ordinary water for the coolant. See the Soviet-made RBMK nuclear-power reactor. This was the type of reactor involved in the Chernobyl disaster.
In the Advanced Gas-cooled Reactor, a British design, the core is made of a graphite neutron moderator where the fuel assemblies are located. Carbon dioxide gas acts as a coolant an |
https://en.wikipedia.org/wiki/Onion%20powder | Onion powder is dehydrated, ground onion that is commonly used as a seasoning. It is a common ingredient in seasoned salt and spice mixes, such as beau monde seasoning. Some varieties are prepared using toasted onion. White, yellow and red onions may be used. Onion powder is a commercially prepared food product that has several culinary uses. Onion powder can also be homemade.
Onion salt is a spice preparation using dried onion and salt as primary ingredients.
Commercial production
Commercial onion powders are prepared using dehydration, freeze-drying, vacuum-shelf drying and flow drying. Some commercial onion powders are irradiated as a treatment against potential microbial contamination. It readily absorbs water upon contact, so commercial varieties may be packaged in airtight containers with a liner atop the container. Onion powder with a moisture content of 4–5 percent is prone to caking when stored in warmer environments, with increased temperatures corresponding to a shorter time for the occurrence of caking. Of general acceptance is that commercial onion powder is around ten times stronger in flavor compared to fresh onion.
Onion salt
Early commercial preparations of onion salt were simply a mixture of onion powder and salt. An example ratio for earlier commercial preparations is one part salt to every five parts of dehydrated onion. Contemporary versions typically utilize dried granulated onion and salt, and usually include an anticaking agent. The salt may serve to prevent the loss of onion flavor in the mixture, by preventing the evaporation of onion oil. The development of commercial onion salt preparations included formulating products that reduced the strong odor of onion in the product and on the breath of consumers who eat it.
Commercial preparation of onion salt involves the testing and sorting of onions by the degree of onion flavor they have, as flavor constituents can vary considerably among various onion varieties. This is performed prior to |
https://en.wikipedia.org/wiki/Intertidal%20zone | The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide: in other words, the part of the littoral zone within the tidal range. This area can include several types of habitats with various species of life, such as seastars, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the littoral zone or seashore, although those can be defined as a wider region.
The well-known area also includes steep rocky cliffs, sandy beaches, bogs or wetlands (e.g., vast mudflats). The area can be a narrow strip, as in Pacific islands that have only a narrow tidal range, or can include many meters of shoreline where shallow beach slopes interact with high tidal excursion. The peritidal zone is similar but somewhat wider, extending from above the highest tide level to below the lowest. Organisms in the intertidal zone are adapted to an environment of harsh extremes, living in water pressure with the potential of reaching 5,580 pounds per square inch. The intertidal zone is also home to several species from different phyla (Porifera, Annelida, Coelenterata, Mollusca, Arthropoda, etc.).
Water is available regularly with the tides that can vary from brackish waters, fresh with rain, to highly saline and dry salt, with drying between tidal inundations. Wave splash can dislodge residents from the littoral zone. With the intertidal zone's high exposure to sunlight, the temperature can range from very hot with full sunshine to near freezing in colder climates. Some microclimates in the littoral zone are moderated by local features and larger plants such as mangroves. Adaptation in the littoral zone allows the use of nutrients supplied in high volume on a regular basis from the sea, which is actively moved to the zone by tides. Edges of habitats, in this case land and sea, are themselves often significant ecologies, and the littoral zone is a prime example.
A typical rocky shore can be di |
https://en.wikipedia.org/wiki/PL-3 | PL-3 or POS-PHY Level 3 is a network protocol. It is the name of the interface that the Optical Internetworking Forum's SPI-3 Interoperability Agreement is based on. It was proposed by PMC-Sierra to the Optical Internetworking Forum and adopted in June 2000. The name means Packet Over SONET Physical layer level 3. PL-3 was developed by PMC-Sierra in conjunction with the SATURN Development Group.
The name is an acronym of an acronym of an acronym as the P in PL stands for "POS-PHY" and the S in POS-PHY stands for "SONET" (Synchronous Optical Network). The L in PL stands for "Layer".
Context
There are two broad categories of chip-to-chip interfaces. The first, exemplified by PCI-Express and HyperTransport, supports reads and writes of memory addresses. The second broad category carries user packets over 1 or more channels and is exemplified by the IEEE 802.3 family of Media Independent Interfaces and the Optical Internetworking Forum family of System Packet Interfaces. Of these last two, the family of System Packet Interfaces is optimized to carry user packets from many channels. The family of System Packet Interfaces is the most important packet-oriented, chip-to-chip interface family used between devices in the Packet over SONET and Optical Transport Network, which are the principal protocols used to carry the internet between cities.
Applications
It was designed to be used in systems that support OC-48 SONET interfaces . A typical application of PL-3 (SPI-3) is to connect a framer device to a network processor. It has been widely adopted by the high speed networking marketplace.
Technical details
The interface consists of (per direction):
32 TTL signals for the data path
8 TTL signals for control
one TTL signal for clock
8 TTL signals for optional additional multi-channel status
There are several clocking options. The interface operates around 100 MHz. Implementations of SPI-3 (PL-3) have been produced which allow somewhat higher clock rates. |
https://en.wikipedia.org/wiki/SPI-3 | SPI-3 or System Packet Interface Level 3 is the name of a chip-to-chip, channelized, packet interface widely used in high-speed communications devices. It was proposed by PMC-Sierra based on their PL-3 interface to the Optical Internetworking Forum and adopted in June 2000. PL-3 was developed by PMC-Sierra in conjunction with the SATURN Development Group.
Applications
It was designed to be used in systems that support OC-48 SONET interfaces . A typical application of SPI-3 is to connect a framer device to a network processor. It has been widely adopted by the high speed networking marketplace.
Technical details
The interface consists of (per direction):
32 TTL signals for the data path
8 TTL signals for control
one TTL signal for clock
8 TTL signals for optional additional multi-channel status
There are several clocking options. The interface operates around 100 MHz. Implementations of SPI-3 (PL-3) have been produced which allow somewhat higher clock rates. This is important when overhead bytes are added to incoming packets.
SPI-3 in the marketplace
SPI-3 (and PL-3) was a highly successful interface with many semiconductor devices produced to it.
See also
System Packet Interface
SPI-4.2
External links
OIF Interoperability Agreements
Network protocols |
https://en.wikipedia.org/wiki/Computational%20immunology | In academia, computational immunology is a field of science that encompasses high-throughput genomic and bioinformatics approaches to immunology. The field's main aim is to convert immunological data into computational problems, solve these problems using mathematical and computational approaches and then convert these results into immunologically meaningful interpretations.
Introduction
The immune system is a complex system of the human body and understanding it is one of the most challenging topics in biology. Immunology research is important for understanding the mechanisms underlying the defense of human body and to develop drugs for immunological diseases and maintain health. Recent findings in genomic and proteomic technologies have transformed the immunology research drastically. Sequencing of the human and other model organism genomes has produced increasingly large volumes of data relevant to immunology research and at the same time huge amounts of functional and clinical data are being reported in the scientific literature and stored in clinical records. Recent advances in bioinformatics or computational biology were helpful to understand and organize these large-scale data and gave rise to new area that is called Computational immunology or immunoinformatics.
Computational immunology is a branch of bioinformatics and it is based on similar concepts and tools, such as sequence alignment and protein structure prediction tools. Immunomics is a discipline like genomics and proteomics. It is a science, which specifically combines immunology with computer science, mathematics, chemistry, and biochemistry for large-scale analysis of immune system functions. It aims to study the complex protein–protein interactions and networks and allows a better understanding of immune responses and their role during normal, diseased and reconstitution states. Computational immunology is a part of immunomics, which is focused on analyzing large-scale experimental data.
His |
https://en.wikipedia.org/wiki/Innate%20immune%20system | The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an alternate defense strategy and is the dominant immune system response found in plants, fungi, insects, and primitive multicellular organisms (see Beyond vertebrates).
The major functions of the innate immune system are to:
recruit immune cells to infection sites by producing chemical factors, including chemical mediators called cytokines
activate the complement cascade to identify bacteria, activate cells, and promote clearance of antibody complexes or dead cells
identify and remove foreign substances present in organs, tissues, blood and lymph, by specialized white blood cells
activate the adaptive immune system through antigen presentation
act as a physical and chemical barrier to infectious agents; via physical measures such as skin and chemical measures such as clotting factors in blood, which are released following a contusion or other injury that breaks through the first-line physical barrier (not to be confused with a second-line physical or chemical barrier, such as the blood–brain barrier, which protects the nervous system from pathogens that have already gained access to the host).
Anatomical barriers
Anatomical barriers include physical, chemical and biological barriers. The epithelial surfaces form a physical barrier that is impermeable to most infectious agents, acting as the first line of defense against invading organisms. Desquamation (shedding) of skin epithelium also helps remove bacteria and other infectious agents that have adhered to the epithelial surface. Lack of blood vessels, the inability of the epidermis to retain moisture, and the presence of sebaceous glands in the dermis, produces an environment unsuitable for the survival of microbes. In the gastrointestinal and respiratory tract, movement due to peristalsis or cilia, respectively, helps remove infectious |
https://en.wikipedia.org/wiki/Carbon%E2%80%93hydrogen%20bond | In chemistry, the carbon-hydrogen bond ( bond) is a chemical bond between carbon and hydrogen atoms that can be found in many organic compounds. This bond is a covalent, single bond, meaning that carbon shares its outer valence electrons with up to four hydrogens. This completes both of their outer shells, making them stable.
Carbon–hydrogen bonds have a bond length of about 1.09 Å (1.09 × 10−10 m) and a bond energy of about 413 kJ/mol (see table below). Using Pauling's scale—C (2.55) and H (2.2)—the electronegativity difference between these two atoms is 0.35. Because of this small difference in electronegativities, the bond is generally regarded as being non-polar. In structural formulas of molecules, the hydrogen atoms are often omitted. Compound classes consisting solely of bonds and bonds are alkanes, alkenes, alkynes, and aromatic hydrocarbons. Collectively they are known as hydrocarbons.
In October 2016, astronomers reported that the very basic chemical ingredients of life—the carbon-hydrogen molecule (CH, or methylidyne radical), the carbon-hydrogen positive ion () and the carbon ion ()—are the result, in large part, of ultraviolet light from stars, rather than in other ways, such as the result of turbulent events related to supernovae and young stars, as thought earlier.
Bond length
The length of the carbon-hydrogen bond varies slightly with the hybridisation of the carbon atom. A bond between a hydrogen atom and an sp2 hybridised carbon atom is about 0.6% shorter than between hydrogen and sp3 hybridised carbon. A bond between hydrogen and sp hybridised carbon is shorter still, about 3% shorter than sp3 C-H. This trend is illustrated by the molecular geometry of ethane, ethylene and acetylene.
Reactions
The C−H bond in general is very strong, so it is relatively unreactive. In several compound classes, collectively called carbon acids, the C−H bond can be sufficiently acidic for proton removal. Unactivated C−H bonds are found in alkanes and are no |
https://en.wikipedia.org/wiki/Catabolite%20activator%20protein | Catabolite activator protein (CAP; also known as cAMP receptor protein, CRP) is a trans-acting transcriptional activator that exists as a homodimer in solution. Each subunit of CAP is composed of a ligand-binding domain at the N-terminus (CAPN, residues 1–138) and a DNA-binding domain at the C-terminus (DBD, residues 139–209). Two cAMP (cyclic AMP) molecules bind dimeric CAP with negative cooperativity. Cyclic AMP functions as an allosteric effector by increasing CAP's affinity for DNA. CAP binds a DNA region upstream from the DNA binding site of RNA Polymerase. CAP activates transcription through protein-protein interactions with the α-subunit of RNA Polymerase. This protein-protein interaction is responsible for (i) catalyzing the formation of the RNAP-promoter closed complex; and (ii) isomerization of the RNAP-promoter complex to the open conformation. CAP's interaction with RNA polymerase causes bending of the DNA near the transcription start site, thus effectively catalyzing the transcription initiation process. CAP's name is derived from its ability to affect transcription of genes involved in many catabolic pathways. For example, when the amount of glucose transported into the cell is low, a cascade of events results in the increase of cytosolic cAMP levels. This increase in cAMP levels is sensed by CAP, which goes on to activate the transcription of many other catabolic genes.
CAP has a characteristic helix-turn-helix motif structure that allows it to bind to successive major grooves on DNA. The two helices are reinforcing, each causing a 43° turn in the structure, with an overall 94° degree turn in the DNA.
This interaction opens up the DNA molecule, allowing RNA polymerase to bind and transcribe the genes involved in lactose catabolism. cAMP-CAP is required for transcription activation of the lac operon.
This requirement reflects the greater simplicity with which glucose may be metabolized in comparison to lactose. The cell "prefers" glucose, and, if i |
https://en.wikipedia.org/wiki/Traction%20%28mechanics%29 | Traction, traction force or tractive force is a force used to generate motion between a body and a tangential surface, through the use of either dry friction or shear force.
It has important applications in vehicles, as in tractive effort.
Traction can also refer to the maximum tractive force between a body and a surface, as limited by available friction; when this is the case, traction is often expressed as the ratio of the maximum tractive force to the normal force and is termed the coefficient of traction (similar to coefficient of friction). It is the force which makes an object move over the surface by overcoming all the resisting forces like friction, normal loads(load acting on the tiers in negative 'Z' axis), air resistance, rolling resistance, etc.
Definitions
Traction can be defined as:
In vehicle dynamics, tractive force is closely related to the terms tractive effort and drawbar pull, though all three terms have different definitions.
Coefficient of traction
The coefficient of traction is defined as the usable force for traction divided by the weight on the running gear (wheels, tracks etc.) i.e.:
usable traction = coefficient of traction x normal force
Factors affecting coefficient of traction
Traction between two surfaces depends on several factors:
Material composition of each surface.
Macroscopic and microscopic shape (texture; macrotexture and microtexture)
Normal force pressing contact surfaces together.
Contaminants at the material boundary including lubricants and adhesives.
Relative motion of tractive surfaces - a sliding object (one in kinetic friction) has less traction than a non-sliding object (one in static friction).
Direction of traction relative to some coordinate system - e.g., the available traction of a tire often differs between cornering, accelerating, and braking.
For low-friction surfaces, such as off-road or ice, traction can be increased by using traction devices that partially penetrate the surface; these device |
https://en.wikipedia.org/wiki/Barry%20%28dog%29 | Barry der Menschenretter (1800–1814), also known as Barry, was a dog of a breed which was later called the St. Bernard that worked as a mountain rescue dog in Switzerland and Italy for the Great St Bernard Hospice. He predates the modern St. Bernard, and was lighter built than the modern breed. He has been described as the most famous St. Bernard, as he was credited with saving more than 40 lives during his lifetime, hence his byname meaning "people rescuer" in German.
The legend surrounding him was that he was killed while attempting a rescue; however, this is untrue. Barry retired to Bern, Switzerland and after his death his body was passed into the care of the Natural History Museum of Bern. His skin has been preserved through taxidermy although his skull was modified in 1923 to match the Saint Bernard of that time period. His story and name have been used in literary works, and a monument to him stands in the Cimetière des Chiens near Paris. At the hospice, one dog has always been named Barry in his honor; and since 2004, the Fondation Barry du Grand Saint Bernard has been set up to take over the responsibility for breeding dogs from the hospice.
History
The first mention in the Great St Bernard Hospice archives of a dog was in 1707 which simply said "A dog was buried by us." The dogs are thought to have been introduced to the monastery as watchdogs at some point between 1660 and 1670. Old skulls from the collection of the Natural History Museum of Bern show that at least two types of dog lived at the hospice. By 1800, the year that Barry was born, it was known that a special kind of dog was being used for rescue work in the pass. This general variety of dog was known as a Küherhund, or cowherd's dog.
Measurements of his preserved body show that Barry was significantly smaller and lighter built than the modern Saint Bernard, weighing between whereas modern Bernards weigh between 54 and 81kg (120 to 180lbs) His current mounted height is approximately , but |
https://en.wikipedia.org/wiki/Rog-2000 | Rog-2000 (pronounced "Rahj-two-thousand", and sometimes spelled "ROG 2000") is a fictional robot that was the first professional creation of comic book artist-writer John Byrne. Rog-2000 serves as the mascot of Byrne Robotics.
Publication history
The character began life during Byrne's fan-artist days in the 1970s, as a spot illustration for Roger Stern and Bob Layton's fanzine CPL (Contemporary Pictorial Literature). Layton gave the character a name (riffing on the amount of "Rogers" – specifically Roger Stern and Roger Slifer – who contributed to CPL), and he and Stern began using him as a magazine mascot, with Byrne supplying additional art. A Rog-2000 story, "The Coming of the Gang", appeared in CPL #11 (1974), written by Stern with art by Byrne and Layton, and featuring caricatures of "the CPL Gang", including Byrne and fellow CPL contributor Duffy Vohland.
On the strength of that fan piece, Charlton Comics writer Nicola Cuti contacted Byrne about drawing the character for professional comic books. During this same period, the CPL Gang was producing the officially sanctioned fanzine Charlton Bullseye. Written by Cuti, "Rog-2000" became one of several alternating backup features in the Charlton Comics superhero series E-Man, starting with the eight-page "That Was No Lady" in issue #6 (Jan. 1975). This marked the color-comics debut of future industry star Byrne, who'd previously drawn a two-page story for Skywald Publications' black-and-white horror-comics magazine Nightmare #20 (Aug. 1974). The character also appeared the same month in the small-press hobbyist magazine The Comic Reader #44 (Jan. 1975).
As Byrne recalled the character's origin in a 2000 interview:
Three additional, seven-page "Rog-2000" stories – "Withering Heights", "The Wish", and "Rog. vs. The Sog", all by Cuti & Byrne – appeared in E-Man #7, 9–10 (March, July–Sept. 1975), respectively. All the Charlton stories were reprinted in Pacific Comics' ROG 2000 #1 (June 1982), as well as in A-Plu |
https://en.wikipedia.org/wiki/History%20of%20classical%20mechanics | This article deals with the history of classical mechanics.
Precursors to classical mechanics
Antiquity
The ancient Greek philosophers, Aristotle in particular, were among the first to propose that abstract principles govern nature. Aristotle argued, in On the Heavens, that terrestrial bodies rise or fall to their "natural place" and stated as a law the correct approximation that an object's speed of fall is proportional to its weight and inversely proportional to the density of the fluid it is falling through. Aristotle believed in logic and observation but it would be more than eighteen hundred years before Francis Bacon would first develop the scientific method of experimentation, which he called a vexation of nature.
Aristotle saw a distinction between "natural motion" and "forced motion", and he believed that 'in a void' i.e.vacuum, a body at rest will remain at rest and a body in motion will continue to have the same motion. In this way, Aristotle was the first to approach something similar to the law of inertia. However, he believed a vacuum would be impossible because the surrounding air would rush in to fill it immediately. He also believed that an object would stop moving in an unnatural direction once the applied forces were removed. Later Aristotelians developed an elaborate explanation for why an arrow continues to fly through the air after it has left the bow, proposing that an arrow creates a vacuum in its wake, into which air rushes, pushing it from behind. Aristotle's beliefs were influenced by Plato's teachings on the perfection of the circular uniform motions of the heavens. As a result, he conceived of a natural order in which the motions of the heavens were necessarily perfect, in contrast to the terrestrial world of changing elements, where individuals come to be and pass away.
There is another tradition that goes back to the ancient Greeks where mathematics is used to analyze bodies at rest or in motion, which may found as early as the |
https://en.wikipedia.org/wiki/Workflow%20pattern | A workflow pattern is a specialized form of design pattern as defined in the area of software engineering or business process engineering. Workflow patterns refer specifically to recurrent problems and proven solutions related to the development of workflow applications in particular, and more broadly, process-oriented applications.
Concept
Workflow patterns are concepts of economised development. Their usage should follow strategies of simplifying maintenance and reducing modelling work.
Workflow is performed in real time. The mechanisms of control must support the typical pace of work. Design patterns must delay execution of workflow.
Aggregation
Workflow patterns may usually be aggregated as chains and the conditions for starting and terminating must be explicitly defined.
Application
Workflow patterns can be applied in various context, hence the conditions for use must be explicitly defined and shown in order to prevent misinterpretation.
Van der Aalst classification
A well-known collection of workflow patterns is that proposed by Wil van der Aalst et al. (2003) in their paper Workflow Patterns. with earlier versions published in 2000–02. This collection of patterns focuses on one specific aspect of process-oriented application development, namely the description of control flow dependencies between activities in a workflow/process. These patterns are divided into the following categories:
Basic Control Patterns
Sequence - execute two or more activities in sequence
Parallel Split - execute two or more activities in any order or in parallel
Synchronize - synchronize two or more activities that may execute in any order or in parallel; do not proceed with the execution of subsequent activities until all preceding activities have completed; also known as barrier synchronization.
Exclusive Choice - choose one execution path from many alternatives based on data that is available when the execution of the process reaches the exclusive choice
Simple Me |
https://en.wikipedia.org/wiki/Hutchinson%27s%20ratio | In ecological theory, the Hutchinson's ratio is the ratio of the size differences between similar species when they are living together as compared to when they are isolated. It is named after G. Evelyn Hutchinson who concluded that various key attributes in species varied according to the ratio of 1:1.1 to 1:1.4.
See also
Hutchinson's rule |
https://en.wikipedia.org/wiki/Blocking%20oscillator | A blocking oscillator (sometimes called a pulse oscillator) is a simple configuration of discrete electronic components which can produce a free-running signal, requiring only a resistor, a transformer, and one amplifying element such as a transistor or vacuum tube. The name is derived from the fact that the amplifying element is cut-off or "blocked" for most of the duty cycle, producing periodic pulses on the principle of a relaxation oscillator. The non-sinusoidal output is not suitable for use as a radio-frequency local oscillator, but it can serve as a timing generator, to power lights, LEDs, EL wire, or small neon indicators. If the output is used as an audio signal, the simple tones are also sufficient for applications such as alarms or a Morse code practice device. Some cameras use a blocking oscillator to strobe the flash prior to a shot to reduce the red-eye effect.
Due to the circuit's simplicity, it forms the basis for many of the learning projects in commercial electronic kits. The secondary winding of the transformer can be fed to a speaker, a lamp, or the windings of a relay. Instead of a resistor, a potentiometer placed in parallel with the timing capacitor permits the frequency to be adjusted freely, but at low resistances the transistor can be overdriven, and possibly damaged. The output signal will jump in amplitude and be greatly distorted.
Circuit operation
The circuit works due to positive feedback through the transformer and involves two times—the time Tclosed when the switch is closed, and the time Topen when the switch is open. The following abbreviations are used in the analysis:
t, time, a variable
Tclosed: instant at the end of the closed cycle, beginning of open cycle. Also a measure of the time duration when the switch is closed.
Topen: instant at the end of the open cycle, beginning of closed cycle. Same as T=0. Also a measure of the time duration when the switch is open.
Vb, source voltage e.g. Vbattery
Vp, voltage across th |
https://en.wikipedia.org/wiki/Vector%20calculus%20identities | The following are important identities involving derivatives and integrals in vector calculus.
Operator notation
Gradient
For a function in three-dimensional Cartesian coordinate variables, the gradient is the vector field:
where i, j, k are the standard unit vectors for the x, y, z-axes. More generally, for a function of n variables , also called a scalar field, the gradient is the vector field:
where are orthogonal unit vectors in arbitrary directions.
As the name implies, the gradient is proportional to and points in the direction of the function's most rapid (positive) change.
For a vector field , also called a tensor field of order 1, the gradient or total derivative is the n × n Jacobian matrix:
For a tensor field of any order k, the gradient is a tensor field of order k + 1.
For a tensor field of order k > 0, the tensor field of order k + 1 is defined by the recursive relation
where is an arbitrary constant vector.
Divergence
In Cartesian coordinates, the divergence of a continuously differentiable vector field is the scalar-valued function:
As the name implies the divergence is a measure of how much vectors are diverging.
The divergence of a tensor field of non-zero order k is written as , a contraction to a tensor field of order k − 1. Specifically, the divergence of a vector is a scalar. The divergence of a higher order tensor field may be found by decomposing the tensor field into a sum of outer products and using the identity,
where is the directional derivative in the direction of multiplied by its magnitude. Specifically, for the outer product of two vectors,
For a tensor field of order k > 1, the tensor field of order k − 1 is defined by the recursive relation
where is an arbitrary constant vector.
Curl
In Cartesian coordinates, for the curl is the vector field:
where i, j, and k are the unit vectors for the x-, y-, and z-axes, respectively.
As the name implies the curl is a measure of how much nearby vectors te |
https://en.wikipedia.org/wiki/Phase-change%20incubator | The phase-change incubator is a low-cost, low-maintenance incubator that tests for microorganisms in water supplies. It uses small balls containing a chemical compound that, when heated and then kept insulated, will stay at 37 °C (approx. 99 °F) for 24 hours. This allows cultures to be tested without the need for a laboratory or an expensive portable incubator. Thus it is particularly useful for poor or remote communities. The phase-change incubator was developed in the late 1990s by Amy Smith, when she was a graduate student at MIT. Smith has also started a non-profit organization called A Drop in the Bucket to distribute the incubators and to train people on how to use them to test water quality. Her “Test Water Cheap” system could be used at remote locations to test for bacteria such as E.coli.
Embrace, an organization that from Stanford University, is applying a similar concept to design low-cost incubators for premature and low birth weight babies in developing countries.
See also
Appropriate technology |
https://en.wikipedia.org/wiki/Phytomenadione | Phytomenadione, also known as vitamin K1 or phylloquinone, is a vitamin found in food and used as a dietary supplement. It is on the World Health Organization's List of Essential Medicines.
As a supplement it is used to treat certain bleeding disorders. This includes warfarin overdose, vitamin K deficiency, and obstructive jaundice. It is also recommended to prevent and treat vitamin K deficiency bleeding in infants. Use is typically recommended by mouth, intramuscular injection or injection under the skin. When given by injection benefits are seen within two hours. Many countries in the world choose intramuscular injections in newborn to keep them safe from severe bleeding (VKDB). It is considered a safe treatment and saves many children from death and severe neurologic deficit every year.
Side effects when given by injection may include pain at the site of injection. Severe allergic reactions may occur when it is injected into a vein or muscle, but this has mainly happened when large doses of a certain type of supplement containing castor oil were given intravenously. Use during pregnancy is considered safe, use is also likely okay during breastfeeding. It works by supplying a required component for making a number of blood clotting factors. Food sources include green vegetables, vegetable oil, and some fruit.
Phytomenadione was first isolated in 1939. In 1943 Edward Doisy and Henrik Dam were given a Nobel Prize for its discovery.
Terminology
Phytomenadione is often also called phylloquinone, vitamin K, or phytonadione.
A stereoisomer of phylloquinone is called vitamin k1 (note the difference in capitalization).
Chemistry
Vitamin K is a fat-soluble vitamin that is stable in air and moisture but decomposes in sunlight. It is a polycyclic aromatic ketone, based on 2-methyl-1,4-naphthoquinone, with a 3-phytyl substituent. It is found naturally in a wide variety of green plants, particularly in leaves, since it functions as an electron acceptor during photosy |
https://en.wikipedia.org/wiki/Email%20tracking | Email tracking is a method for monitoring whether the email message is read by the intended recipient. Most tracking technologies use some form of digitally time-stamped record to reveal the exact time and date when an email is received or opened, as well as the IP address of the recipient.
Email tracking is useful when the sender wants to know whether the intended recipient actually received the email or clicked the links. However, due to the nature of the technology, email tracking cannot be considered an absolutely accurate indicator that a message was opened or read by the recipient.
Most email marketing software provides tracking features, sometimes in aggregate (e.g., click-through rate), and sometimes on an individual basis.
Read-receipts
Some email applications, such as Microsoft Office Outlook and Mozilla Thunderbird, employ a read-receipt tracking mechanism. The sender selects the receipt request option prior to sending the message, and then upon sending, each recipient has the option of notifying the sender that the message was received or read by the recipient.
However, requesting a receipt does not guarantee that one will be received, for several reasons. Not all email applications or services support sending read receipts, and users can usually disable the functionality if they so wish. Those that do support it are not necessarily compatible with or capable of recognizing requests from a different email service or application. Generally, read receipts are only useful within an organization where all mail users are using the same email service and application.
Depending on the recipient's mail client and settings, they may be forced to click a notification button before they can move on with their work. Even though it is an opt-in process, a recipient might consider it inconvenient, discourteous, or invasive.
Read receipts are sent back to the sender's "inbox" as email messages, but the location may be changed depending on the software used and i |
https://en.wikipedia.org/wiki/Council%20for%20Responsible%20Genetics | The Council for Responsible Genetics (CRG) was a nonprofit NGO with a focus on biotechnology.
History
The Council for Responsible Genetics was founded in 1983 in Cambridge, Massachusetts.
An early voice concerned about the social and ethical implications of modern genetic technologies, CRG organized a 1985 Congressional Briefing and a 1986 panel of the American Association for the Advancement of Science, both focusing on the potential dangers of genetically engineered biological weapons. Francis Boyle was asked to draft legislation setting limits on the use of genetic engineering, leading to the Biological Weapons Anti-Terrorism Act of 1989.
CRG was the first organization to advance a comprehensive, scientifically based position against human germline engineering. It was also the first to compile documented cases of genetic discrimination, laying the intellectual groundwork for the Genetic Information Nondiscrimination Act of 2008 (GINA).
The organization created both a Genetic Bill of Rights and a Citizen's Guide to Genetically Modified Food. Also notable are CRG's support for the "Safe Seeds Campaign" (for avoiding gene flow from genetically engineered to non-GE seed) and the organization of a US conference on Forensic DNA Databanks and Racial Disparities in the Criminal Justice System. In 2010 CRG led a successful campaign to roll back a controversial student genetic testing program at the University of California, Berkeley. In 2011, CRG led a campaign to successfully enact [CalGINA] in California, which extended genetic privacy and nondiscrimination protections to life, disability and long term care insurance, mortgages, lending and other areas.
CRG issued five anthologies of commentaries:
Rights and Liberties in the Biotech Age edited by Sheldon Krimsky and Peter Shorett
Race and the Genetic Revolution: Science, Myth and Culture
Genetic Explanations: Sense and Nonsense edited by Krimsky and Jeremy Gruber
Biotechnology in our Lives edited by Krim |
https://en.wikipedia.org/wiki/Online%20diary | An online diary or web diary, is a personal diary or journal that is published on the World Wide Web on a personal website or a diary-hosting website.
Overview
Online diaries have existed since at least 1994. As a community formed, these publications came to be almost exclusively known as online journals. Today they are almost exclusively called blogs, though some differentiate by calling them personal blogs. The running updates of online diarists combined with links inspired the term 'weblog' which was eventually contracted to form the word 'blog'.
In online diaries, people write about their day-to-day experiences, social commentary, complaints, poems, prose, illicit thoughts and any content that might be found in a traditional paper diary or journal. They often allow readers to contribute through comments or community posting.
Modern online diary platforms may allow the writer to make entries from a PC, tablet or smartphone. Writers might rate how they feel each day, invite someone to engage in a personal conversation or find counseling.
Early history
Online diaries soon caught the attention of the media with the publication of the book 24 Hours in Cyberspace (1996) which captured personal profiles of the people involved in early web pages. The earliest book-length scholarly discussion of online diaries is Philippe Lejeune's Cher écran, ("Dear Screen").
In 1998, Simon Firth described in Salon magazine how many early online diarists were abandoning the form. Yet, he said, "While many of the movement's pioneers may be tired and disillusioned, the genre shows plenty of signs of life – of blossoming, even, into something remarkable: a new literary form that allows writers to connect with readers in an excitingly new way."
Formation of a community
As diarists (sometimes called escribitionists) began to learn from each other, several Webrings formed to connect various diaries and journals; the most popular was Open Pages, which started in July 1996 and had 537 |
https://en.wikipedia.org/wiki/Screenless%20hammer%20mill | The screenless hammer mill, like regular hammer mills, is used to pound grain. However, rather than a screen, it uses air flow to separate small particles from larger ones.
Conventional hammer mills in poor and remote areas, such as many parts of Africa, suffer from the problem that screens break easily, and cannot be easily bought, made or repaired. Thus regular hammer mills break down and fall into disuse. The screenless hammer mill uses air flow to separate small particles from larger ones, rather than a screen, and is thus more reliable.
The screenless hammer mill is claimed to be 25% cheaper and much more energy efficient than regular hammer mills, as well as more reliable.
It was designed by Amy Smith of MIT.
See also
Appropriate technology
External links
Mill Field Testing in Senegal
Necessity Is the Mother of Invention
A MacGyver for the Third World |
https://en.wikipedia.org/wiki/Erd%C5%91s%E2%80%93Szekeres%20theorem | In mathematics, the Erdős–Szekeres theorem asserts that, given r, s, any sequence of distinct real numbers with length at least (r − 1)(s − 1) + 1 contains a monotonically increasing subsequence of length r or a monotonically decreasing subsequence of length s. The proof appeared in the same 1935 paper that mentions the Happy Ending problem.
It is a finitary result that makes precise one of the corollaries of Ramsey's theorem. While Ramsey's theorem makes it easy to prove that every infinite sequence of distinct real numbers contains a monotonically increasing infinite subsequence or a monotonically decreasing infinite subsequence, the result proved by Paul Erdős and George Szekeres goes further.
Example
For r = 3 and s = 2, the formula tells us that any permutation of three numbers has an increasing subsequence of length three or a decreasing subsequence of length two. Among the six permutations of the numbers 1,2,3:
1,2,3 has an increasing subsequence consisting of all three numbers
1,3,2 has a decreasing subsequence 3,2
2,1,3 has a decreasing subsequence 2,1
2,3,1 has two decreasing subsequences, 2,1 and 3,1
3,1,2 has two decreasing subsequences, 3,1 and 3,2
3,2,1 has three decreasing length-2 subsequences, 3,2, 3,1, and 2,1.
Alternative interpretations
Geometric interpretation
One can interpret the positions of the numbers in a sequence as x-coordinates of points in the Euclidean plane, and the numbers themselves as y-coordinates; conversely, for any point set in the plane, the y-coordinates of the points, ordered by their x-coordinates, forms a sequence of numbers (unless two of the points have equal x-coordinates). With this translation between sequences and point sets, the Erdős–Szekeres theorem can be interpreted as stating that in any set of at least rs − r − s + 2 points we can find a polygonal path of either r − 1 positive-slope edges or s − 1 negative-slope edges. In particular (taking r = s), in any set of at least n points we can find a |
https://en.wikipedia.org/wiki/Cardiorespiratory%20fitness | Cardiorespiratory fitness (CRF) refers to the ability of the circulatory and respiratory systems to supply oxygen to skeletal muscles during sustained physical activity. Scientists and researchers use CRF to assess the functional capacity of the respiratory and cardiovascular systems. These functions include ventilation, perfusion, gas exchange, vasodilation, and delivery of oxygen to the body's tissues. As these body's functions are vital to an individual's health, CRF allows observers to quantify an individual's morbidity and mortality risk as a function of cardiorespiratory health.
In 2016, the American Heart Association published an official scientific statement advocating that CRF, quantifiable as V̇O2 max/peak, be categorized as a clinical vital sign and should be routinely assessed as part of clinical practice. Low levels of CRF have been shown to increase the risk of cardiovascular disease (CVD) and all-cause mortality. Some medical researchers claim that CRF is an even stronger predictor of mortality than smoking, hypertension, high cholesterol, type 2 diabetes mellitus, or other common risk factors.
Regular physical activity and exercise can improve CRF, thus decreasing risk of CVD and other conditions while improving overall health.
History and etymology
The emergence of a method to quantify CRF began in the 1920s when Archibald Hill, a British physiologist, proposed a multifactorial relationship between the maximum rate of oxygen uptake by body tissues and intensity of physical activity. This measure was found to be dependent upon functional capacities of an individual's cardiovascular and respiratory systems. He coined the term VO2 max, or maximal oxygen consumption, the numerical result of exercise testing that represents the maximum rate of oxygen consumed per kilogram of body mass per minute during exercise which now serves as the primary measure of CRF. This proposal ignited a multitude of studies demonstrating a relationship between VO2 max and |
https://en.wikipedia.org/wiki/Tverberg%27s%20theorem | In discrete geometry, Tverberg's theorem, first stated by Helge Tverberg in 1966, is the result that sufficiently many points in d-dimensional Euclidean space can be partitioned into subsets with intersecting convex hulls. Specifically, for any positive integers d, r and any set of
points there exists a point x (not necessarily one of the given points) and a partition of the given points into r subsets, such that x belongs to the convex hull of all of the subsets. The partition resulting from this theorem is known as a Tverberg partition.
The special case r = 2 was proved earlier by Radon, and it is known as Radon's theorem.
Examples
The case d = 1 states that any 2r-1 points on the real line can be partitioned into r subsets with intersecting convex hulls. Indeed, if the points are x1 < x2 < ... < x2r < x2r-1, then the partition into Ai = {xi, x2r-i} for i in 1,...,r satisfies this condition (and it is unique).
For r = 2, Tverberg's theorem states that any d + 2 points may be partitioned into two subsets with intersecting convex hulls. This is known as Radon's theorem. In this case, for points in general position, the partition is unique.
The case r = 3 and d = 2 states that any seven points in the plane may be partitioned into three subsets with intersecting convex hulls. The illustration shows an example in which the seven points are the vertices of a regular heptagon. As the example shows, there may be many different Tverberg partitions of the same set of points; these seven points may be partitioned in seven different ways that differ by rotations of each other.
Topological Tverberg Theorem
An equivalent formulation of Tverberg's theorem is:Let d, r be positive integers, and let N := (d+1)(r-1). If ƒ is any affine function from an N-dimensional simplex ΔN to Rd, then there are r pairwise-disjoint faces of ΔN whose images under ƒ intersect. That is: there exist faces F1,...,Fr of ΔN such that and .They are equivalent because any affine function on a sim |
https://en.wikipedia.org/wiki/Urca%20process | In astroparticle physics, an Urca process is a reaction which emits a neutrino and which is assumed to take part in cooling processes in neutron stars and white dwarfs. The process was first discussed by George Gamow and Mário Schenberg while they were visiting a casino named Cassino da Urca in Urca, Rio de Janeiro. As Gamow recounts in his autobiography, the name was chosen in part to commemorate the gambling establishment where the two physicists had first met, and "partially because the Urca Process results in a rapid disappearance of thermal energy from the interior of a star, similar to the rapid disappearance of money from the pockets of the gamblers on the Casino de Urca." In Gamow's South Russian dialect, urca () can also mean a robber or gangster.
The direct Urca processes are the simplest neutrino-emitting processes and are thought to be central in the cooling of neutron stars. They have the general form
{|
| B || || || → || B || + || || + || ,
|------------------------------------------
| B || + || || → || B || + ||,
|}
where B and B are baryons, is a lepton, and (and ) are (anti-)neutrinos. The baryons can be nucleons (free or bound), hyperons like , and , or members of the isobar. The lepton is either an electron or a muon.
The Urca process is especially important in the cooling of white dwarfs, where a lepton (usually an electron) is absorbed by the nucleus of an ion and then convectively carried away from the core of a star. Then, a beta decay occurs. Convection then carries the element back into the interior of the star, and the cycle repeats many times. Because the neutrinos emitted during this process are unlikely to be reabsorbed, this is effectively a cooling mechanism for white dwarfs.
The process can also be essential in the cooling of neutron stars. If a neutron star contains a central core in which the direct Urca-process is operative, the cooling timescale shortens by many ord |
https://en.wikipedia.org/wiki/Cartan%20formula | In mathematics, Cartan formula can mean:
one in differential geometry: , where , and are Lie derivative, exterior derivative, and interior product, respectively, acting on differential forms. See interior product for the detail. It is also called the Cartan homotopy formula or Cartan magic formula. This formula is named after Élie Cartan.
one in algebraic topology, which is one of the five axioms of Steenrod algebra. It reads:
.
See Steenrod algebra for the detail. The name derives from Henri Cartan, son of Élie.
Footnotes
See also
List of things named after Élie Cartan |
https://en.wikipedia.org/wiki/Complete%20intersection | In mathematics, an algebraic variety V in projective space is a complete intersection if the ideal of V is generated by exactly codim V elements. That is, if V has dimension m and lies in projective space Pn, there should exist n − m homogeneous polynomials:
in the homogeneous coordinates Xj, which generate all other homogeneous polynomials that vanish on V.
Geometrically, each Fi defines a hypersurface; the intersection of these hypersurfaces should be V. The intersection of hypersurfaces will always have dimension at least m, assuming that the field of scalars is an algebraically closed field such as the complex numbers. The question is essentially, can we get the dimension down to m, with no extra points in the intersection? This condition is fairly hard to check as soon as the codimension . When then V is automatically a hypersurface and there is nothing to prove.
Examples
Easy examples of complete intersections are given by hypersurfaces which are defined by the vanishing locus of a single polynomial. For example,
gives an example of a quintic threefold. It can be difficult to find explicit examples of complete intersections of higher dimensional varieties using two or more explicit examples (bestiary), but, there is an explicit example of a 3-fold of type given by
Non-examples
Twisted cubic
One method for constructing local complete intersections is to take a projective complete intersection variety and embed it into a higher dimensional projective space. A classic example of this is the twisted cubic in : it is a smooth local complete intersection meaning in any chart it can be expressed as the vanishing locus of two polynomials, but globally it is expressed by the vanishing locus of more than two polynomials. We can construct it using the very ample line bundle over giving the embedding
by
Note that . If we let the embedding gives the following relations:
Hence the twisted cubic is the projective scheme
Union of varieties differing in dim |
https://en.wikipedia.org/wiki/List%20of%20textbooks%20in%20thermodynamics%20and%20statistical%20mechanics | A list of notable textbooks in thermodynamics and statistical mechanics, arranged by category and date.
Only or mainly thermodynamics
Both thermodynamics and statistical mechanics
2e Kittel, Charles; and Kroemer, Herbert (1980) New York: W.H. Freeman
2e (1988) Chichester: Wiley , .
(1990) New York: Dover
Statistical mechanics
. 2e (1936) Cambridge: University Press; (1980) Cambridge University Press.
; (1979) New York: Dover
Vol. 5 of the Course of Theoretical Physics. 3e (1976) Translated by J.B. Sykes and M.J. Kearsley (1980) Oxford : Pergamon Press.
. 3e (1995) Oxford: Butterworth-Heinemann
. 2e (1987) New York: Wiley
. 2e (1988) Amsterdam: North-Holland . 2e (1991) Berlin: Springer Verlag ,
; (2005) New York: Dover
2e (2000) Sausalito, Calif.: University Science
2e (1998) Chichester: Wiley
Specialized topics
Kinetic theory
Vol. 10 of the Course of Theoretical Physics (3rd Ed). Translated by J.B. Sykes and R.N. Franklin (1981) London: Pergamon ,
Quantum statistical mechanics
Mathematics of statistical mechanics
Translated by G. Gamow (1949) New York: Dover
. Reissued (1974), (1989); (1999) Singapore: World Scientific
; (1984) Cambridge: University Press . 2e (2004) Cambridge: University Press
Miscellaneous
(available online here)
Historical
(1896, 1898) Translated by Stephen G. Brush (1964) Berkeley: University of California Press; (1995) New York: Dover
Translated by J. Kestin (1956) New York: Academic Press.
German Encyclopedia of Mathematical Sciences. Translated by Michael J. Moravcsik (1959) Ithaca: Cornell University Press; (1990) New York: Dover
See also
List of textbooks on classical mechanics and quantum mechanics
List of textbooks in electromagnetism
List of books on general relativity
Further reading |
https://en.wikipedia.org/wiki/Tensor%20fasciae%20latae%20muscle | The tensor fasciae latae (or tensor fasciæ latæ or, formerly, tensor vaginae femoris) is a muscle of the thigh. Together with the gluteus maximus, it acts on the iliotibial band and is continuous with the iliotibial tract, which attaches to the tibia. The muscle assists in keeping the balance of the pelvis while standing, walking, or running.
Structure
It arises from the anterior part of the outer lip of the iliac crest; from the outer surface of the anterior superior iliac spine, and part of the outer border of the notch below it, between the gluteus medius and sartorius; and from the deep surface of the fascia lata.
It is inserted between the two layers of the iliotibial tract of the fascia lata about the junction of the middle and upper thirds of the thigh. The tensor fasciae latae tautens the iliotibial tract and braces the knee, especially when the opposite foot is lifted. The terminal insertion point lies on the lateral condyle of the tibia.
Nerve supply
Tensor fasciae latae is innervated by the superior gluteal nerve, L5 and S1. At its origins of the anterior rami of L4, L5, and S1 nerves, the superior gluteal nerve exits the pelvis via greater sciatic foramen superior to the piriformis. The nerve also courses between the gluteus medius and minimus. The superior gluteal artery also supplies the tensor fasciae latae. The superior gluteal nerve arises from the sacral plexus and only has muscular innervation associated with it. There is no cutaneous innervation for sensation that stems from the superior gluteal nerve.
Function
The tensor fasciae latae is a tensor of the fascia lata; continuing its action, the oblique direction of its fibers enables it to stabilize the hip in extension (assists gluteus maximus during hip extension). The fascia lata is a fibrous sheath that encircles the thigh like a subcutaneous stocking and tightly binds its muscles. On the lateral surface, it combines with the tendons of the gluteus maximus and tensor fasciae latae to |
https://en.wikipedia.org/wiki/Timing%20mark | A timing mark is an indicator used for setting the timing of the ignition system of an engine, typically found on the crankshaft pulley (as pictured) or the flywheel. These have the largest radius rotating at crankshaft speed and therefore are the place where marks at one degree intervals will be farthest apart.
On older engines it is common to set the ignition timing using a timing light, which flashes in time with the ignition system (and hence engine rotation). Shining the light on the timing marks makes them appear stationary due to the stroboscopic effect. The ignition timing can then be adjusted to fire at the correct point in the engine's rotation, typically a few degrees before top dead centre and advancing with increasing engine speed. The timing can be adjusted by loosening and slightly rotating the distributor in its seat.
Modern engines usually use a crank sensor directly connected to the engine management system.
The term can also be used to describe the tick marks along the length of an optical mark recognition sheet, used to confirm the location of the sheet as it passes through the reader. See, for example, U.S. Patent 3,218,439 (filed 1964, granted 1965), which refers to a timing track down the left side of the form, and U.S. Patent 3,267,258 (filed 1963, granted 1966), which refers to a column of timing marks on the right side of the form.
The term can also be used to describe the timing patterns used in some barcodes, such as PostBar, Data Matrix, Aztec Code, etc. |
https://en.wikipedia.org/wiki/GIO | GIO is a computer bus standard developed by SGI and used in a variety of their products in the 1990s as their primary expansion system. GIO was similar in concept to competing standards such as NuBus or (later) PCI, but saw little use outside SGI and severely limited the devices available on their platform as a result. Most devices using GIO were SGI's own graphics cards, although a number of cards supporting high-speed data access such as Fibre Channel and FDDI were available from third parties. Later SGI machines use the XIO bus, which is laid out as a computer network as opposed to a bus.
Description
Like most busses of the era, GIO was a 32-bit address and data multiplexed bus that was normally clocked at 25 or 33 MHz. This meant that the bus uses the same path for addressing and data, thus normally requiring three cycles to transfer a single 32-bit value; one cycle to send the address, the next to send the data and then another to read or write it. This limited the bus to a maximum throughput of about 16 Mbyte/s at 33 MHz for these sorts of small transfers. However the system also included a long-burst read/write mode that allowed continual transfers of up to 4 kilobytes of data (the fundamental page size in R3000-based SGI machines); using this mode dramatically increased the throughput to 132 Mbyte/s (32 bits per cycle * 33 MHz). GIO also included a "real time" interrupt allowing devices to interrupt these long transfers if needed. Bus arbitration was controlled by the Processor Interface Controller (PIC) in the original R3000-based SGI Indigo systems.
Physically, GIO used a 96-pin connector and fairly small cards 6.44 inches (16.3576 cm) long by 3.375 inches (8.5725 cm) wide. In the Indigo series, the cards were aligned vertically above each other within the case, as opposed to the more common arrangement where the cards lie at right angles to the motherboard. This led to a "tall and skinny" case design. Since the cards were "above" each other in-line, i |
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