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Primitive Clay Oven
The primitive clay oven, or earthen oven / cob oven, has been used since time immemorial by diverse cultures and societies, primarily for, but not exclusive to, baking before the invention of cast-iron stoves, and gas and electric ovens. The general build and shape were, mostly, common to all peoples, with only slight variations in size and in materials used to construct the oven. In primitive courtyards and farmhouses, earthen ovens were built on the ground. In Arabian, Palestinian, Middle-Eastern and North-African societies, bread was often baked within a clay oven called in some Arabic dialects a tabun (also transliterated taboon, from the Arabic: طابون), or else in a clay oven called a tannour, and in other dialects mas'ad. The clay oven, synonymous with the Hebrew word tannour (= oven), was shaped like a truncated cone, with an opening either at the top or bottom from which to stoke the fire. Others were made cylindrical with an opening at the top. Built and used in biblical times as the family, neighbourhood, or village oven, clay ovens continue to be made in parts of the Middle East today.
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  • 22 Nov 2022
Topic Review
Paediatric Multisystem Inflammatory Syndrome
Paediatric multisystem inflammatory syndrome (PMIS), or multisystem inflammatory syndrome in children (MIS-C), is a systemic disease involving persistent fever, inflammation and organ dysfunction following exposure to SARS-CoV-2, the virus responsible for COVID-19. This syndrome appears somewhat similar to Kawasaki disease, a rare disease of unknown origin that affects young children, in which blood vessels become inflamed throughout the body. It can also show features of other serious paediatric inflammatory conditions, including toxic shock and macrophage activation syndromes. Older children tend to be affected. The first symptoms may be acute abdominal pain, diarrhoea or vomiting. Low blood pressure is common. Other possible symptoms include conjunctivitis, rashes, enlarged lymph nodes, swollen hands and feet, "strawberry tongue", sore throat, cough, fainting, irritability and confusion. Inflammation of the heart muscle is one of several forms of cardiac involvement. Coronary artery abnormalities (such as dilatation and aneurysms) can occur. A cytokine storm may take place, in which the innate immune system stages an excessive and uncontrolled inflammatory response. For the purposes of diagnosis and official reporting of cases, this emerging condition has been defined in three different ways (using various names), by the World Health Organization (WHO), the Royal College of Paediatrics and Child Health (RCPCH), and the Centers for Disease Control and Prevention (CDC). Although the condition is thought to follow SARS-CoV-2 viral infection, antigen or antibody tests are not always positive. Exclusion of alternative causes, including bacterial and other infections, is essential for differential diagnosis. Some general clinical guidance has been provided by the RCPCH, the National Institutes of Health, the American College of Rheumatology, and the American Academy of Pediatrics. Limited information exists regarding clinical course of this life-threatening disease, which has occasionally proved fatal. Failure of one or more organs can occur. Early recognition and prompt specialist attention are essential. Supportive care is key. Anti-inflammatory treatments have been used, with good responses being recorded for intravenous immunoglobulin (IVIG), with or without corticosteroids. Oxygen therapy may be needed, and some children require paediatric intensive care. Clusters of new cases have emerged 2–4 weeks after local peaks in viral transmission. It is thought that the disease may be driven by a delayed biological mechanism in certain predisposed children. The condition is considered rare. The European Centre for Disease Prevention and Control (ECDC) has rated risk to children in Europe as being 'low' overall, based on a 'very low' likelihood of a child developing this 'high impact' disease. Initial reports regarded children in various parts of Europe and the U.S., and it is unclear to what extent the condition has gone unrecognized elsewhere.
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  • 22 Nov 2022
Topic Review
List of the Named Buddhas
In countries where Theravāda Buddhism is practiced by the majority of people, such as Sri Lanka, Cambodia, Laos, Myanmar, Thailand, it is customary for Buddhists to hold elaborate festivals, especially during the fair weather season, paying homage to the 29 Buddhas described in the Buddhavamsa. The Buddhavamsa is a text which describes the life of Gautama Buddha and the 27 Buddhas who preceded him, along with the future Metteyya Buddha. The Buddhavamsa is part of the Khuddaka Nikāya, which in turn is part of the Sutta Piṭaka. The Sutta Piṭaka is one of three main sections of the Pāli Canon of Theravāda Buddhism. The first three of these Buddhas—Taṇhaṅkara, Medhaṅkara, and Saraṇaṅkara—lived before the time of Dīpankara Buddha. The fourth Buddha, Dīpankara, is especially important, as he was the Buddha who gave niyatha vivarana (prediction of future Buddhahood) to the Brahmin youth who would in the distant future become the bodhisattva Gautama Buddha. After Dīpankara, 25 more noble people (ariya-puggala) would attain enlightenment before Gautama, the historical Buddha. Many Buddhists also pay homage to the future (and 29th) Buddha, Maitreya. According to Buddhist scripture, Maitreya will be a successor of Gautama who will appear on Earth, achieve complete enlightenment, and teach the pure Dharma. The prophecy of the arrival of Maitreya is found in the canonical literature of all Buddhist sects (Theravada, Mahayana, and Vajrayana), and is accepted by most Buddhists as a statement about an event that will take place when the Dharma will have been forgotten on Jambudvipa (the terrestrial realm, where ordinary human beings live).
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  • 22 Nov 2022
Topic Review
Lens (Anatomy)
The lens, or crystalline lens is a transparent biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, it functions to change the focal length of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. This adjustment of the lens is known as accommodation (see also below). Accommodation is similar to the focusing of a photographic camera via movement of its lenses. The lens is flatter on its anterior side than on its posterior side. In humans, the refractive power of the lens in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power.
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  • 21 Nov 2022
Topic Review
Gent (Hyperelastic Model)
The Gent hyperelastic material model is a phenomenological model of rubber elasticity that is based on the concept of limiting chain extensibility. In this model, the strain energy density function is designed such that it has a singularity when the first invariant of the left Cauchy-Green deformation tensor reaches a limiting value [math]\displaystyle{ I_m }[/math]. The strain energy density function for the Gent model is where [math]\displaystyle{ \mu }[/math] is the shear modulus and [math]\displaystyle{ J_m = I_m -3 }[/math]. In the limit where [math]\displaystyle{ I_m \rightarrow \infty }[/math], the Gent model reduces to the Neo-Hookean solid model. This can be seen by expressing the Gent model in the form A Taylor series expansion of [math]\displaystyle{ \ln\left[1 - (I_1-3)x\right] }[/math] around [math]\displaystyle{ x = 0 }[/math] and taking the limit as [math]\displaystyle{ x\rightarrow 0 }[/math] leads to which is the expression for the strain energy density of a Neo-Hookean solid. Several compressible versions of the Gent model have been designed. One such model has the form (the below strain energy function yields a non zero hydrostatic stress at no deformation, refer https://link.springer.com/article/10.1007/s10659-005-4408-x for compressible Gent models). where [math]\displaystyle{ J = \det(\boldsymbol{F}) }[/math], [math]\displaystyle{ \kappa }[/math] is the bulk modulus, and [math]\displaystyle{ \boldsymbol{F} }[/math] is the deformation gradient.
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  • 21 Nov 2022
Topic Review
Determining Number of Clusters in a Data Set
For a certain class of clustering algorithms (in particular k-means, k-medoids and expectation–maximization algorithm), there is a parameter commonly referred to as k that specifies the number of clusters to detect. Other algorithms such as DBSCAN and OPTICS algorithm do not require the specification of this parameter; hierarchical clustering avoids the problem altogether. The correct choice of k is often ambiguous, with interpretations depending on the shape and scale of the distribution of points in a data set and the desired clustering resolution of the user. In addition, increasing k without penalty will always reduce the amount of error in the resulting clustering, to the extreme case of zero error if each data point is considered its own cluster (i.e., when k equals the number of data points, n). Intuitively then, the optimal choice of k will strike a balance between maximum compression of the data using a single cluster, and maximum accuracy by assigning each data point to its own cluster. If an appropriate value of k is not apparent from prior knowledge of the properties of the data set, it must be chosen somehow. There are several categories of methods for making this decision.
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  • 22 Nov 2022
Topic Review
List of Thor and Delta Launches (1960–69)
Between 1960 and 1969, there were 314 Thor missiles launched, of which 272 were successful, giving an 86.6% success rate.
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  • 21 Nov 2022
Topic Review
Combating Online Infringement and Counterfeits Act
United States Senate Bill S.3804, known as the Combating Online Infringement and Counterfeits Act (COICA) was a bill introduced by Senator Patrick Leahy (D-VT) on September 20, 2010. It proposed amendments to Chapter 113 of Title 18 of the United States Code that would authorize the Attorney General to bring an in rem action against any domain name found "dedicated to infringing activities", as defined within the text of the bill. Upon bringing such an action, and obtaining an order for relief, the registrar of, or registry affiliated with, the infringing domain would be compelled to "suspend operation of and lock the domain name." The bill was supported by the Motion Picture Association of America, the U.S. Chamber of Commerce, the Screen Actors Guild, Viacom, and the International Alliance of Theatrical Stage Employees, Moving Picture Technicians, Artists and Allied Crafts of the United States. It was opposed by organizations and individuals such as Center for Democracy and Technology, the Electronic Frontier Foundation, Demand Progress, the Distributed Computing Industry Association, Tim Berners-Lee, the American Civil Liberties Union and Human Rights Watch. The bill passed the Senate Judiciary Committee with a vote of 19-0 but never received a full vote on the Senate floor. Senator Ron Wyden (D-OR) announced he would take the steps necessary to halt COICA so it is not enacted into law in 2010, and was successful, effectively killing this bill and requiring it to be resubmitted and for it to make it through a new committee again in 2011 with a different makeup of its members. The Act was rewritten as the Protect IP Act.
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  • 21 Nov 2022
Topic Review
Landesrabbiner
Landesrabbiner (German: [ˈlandəs.ʁaˌbiːnɐ]; Hebrew: רב מדינה‎, romanized: Rav Medinah) are spiritual heads of the Jewish communities of a country, province, or district, particularly in Germany and Austria. The office is a result of the legal condition of the Jews in medieval times when the Jewish communities formed a unit for the purposes of taxation. As the community had to pay certain taxes to the government, the latter had to appoint some one who should be responsible to it for their prompt collection, and who consequently had to be invested with a certain authority. The office of Landesrabbiner had no ecclesiastical meaning until the 18th century, when the various governments began to consider it their duty to care for the spiritual welfare of the Jews. Such ecclesiastical authority, owing to the strictly congregational constitution of the communities, never took root among the Jews (see, however, on the chief rabbinate of Moravia after the death of Marcus Benedict, Moses Sofer, Responsa, Oraḥ Ḥayyim, 13).
  • 675
  • 22 Nov 2022
Topic Review
Vincent Stomatitis
Acute necrotizing ulcerative gingivitis (ANUG) is a common, non-contagious infection of the gums with sudden onset. The main features are painful, bleeding gums, and ulceration of inter-dental papillae (the sections of gum between adjacent teeth). This disease, along with necrotizing (ulcerative) periodontitis (NP or NUP) is classified as a necrotizing periodontal disease, one of the seven general types of gum disease caused by inflammation of the gums (periodontitis). The often severe gum pain that characterizes ANUG distinguishes it from the more common chronic periodontitis which is rarely painful. If ANUG is improperly treated or neglected, it may become chronic and/or recurrent. The causative organisms are mostly anaerobic bacteria, particularly Fusobacteriota and spirochete species. Predisposing factors include poor oral hygiene, smoking, poor nutrition, psychological stress, and a weakened immune system. When the attachments of the teeth to the bone are involved, the term NUP is used. Treatment of ANUG is by removal of dead gum tissue and antibiotics (usually metronidazole) in the acute phase, and improving oral hygiene to prevent recurrence. Although the condition has a rapid onset and is debilitating, it usually resolves quickly and does no serious harm. The informal name trench mouth arose during World War I as many soldiers developed the disease, probably because of the poor conditions and extreme psychological stress.
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  • 21 Nov 2022
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