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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Thermal Conductivity Measurement
There are a number of possible ways to measure thermal conductivity, each of them suitable for a limited range of materials, depending on the thermal properties and the medium temperature. Three classes of methods exist to measure the thermal conductivity of a sample: steady-state, time-domain, and frequency-domain methods.
  • 2.9K
  • 24 Oct 2022
Topic Review
Domestic Violence
Domestic violence (also called domestic abuse or family violence) is violence or other abuse that occurs in a domestic setting, such as in a marriage or cohabitation. Domestic violence is often used as a synonym for intimate partner violence, which is committed by one of the people in an intimate relationship against the other person, and can take place in relationships or between former spouses or partners. In its broadest sense, domestic violence also involves violence against children, parents, or the elderly. It can assume multiple forms, including physical, verbal, emotional, economic, religious, reproductive, or sexual abuse. It can range from subtle, coercive forms to marital rape and other violent physical abuse, such as choking, beating, female genital mutilation, and acid throwing that may result in disfigurement or death, and includes the use of technology to harass, control, monitor, stalk or hack. Domestic murder includes stoning, bride burning, honor killing, and dowry death, which sometimes involves non-cohabitating family members. Globally, the victims of domestic violence are overwhelmingly women, and women tend to experience more severe forms of violence. They are also likelier than men to use intimate partner violence in self-defense. In some countries, domestic violence may be seen as justified or legally permitted, particularly in cases of actual or suspected infidelity on the part of the woman. Research has established that there exists a direct and significant correlation between a country's level of gender equality and rates of domestic violence, where countries with less gender equality experience higher rates of domestic violence. Domestic violence is among the most underreported crimes worldwide for both men and women. In addition, due to social stigmas regarding male victimization, men who are victims of domestic violence face an increased likelihood of being overlooked by healthcare providers. Domestic violence often occurs when the abuser believes that they are entitled to it, or that it is acceptable, justified, or unlikely to be reported. It may produce an intergenerational cycle of violence in children and other family members, who may feel that such violence is acceptable or condoned. Many people do not recognize themselves as abusers or victims, because they may consider their experiences as family conflicts that had gotten out of control. Awareness, perception, definition and documentation of domestic violence differs widely from country to country. Additionally, domestic violence often happens in the context of forced or child marriages. In abusive relationships, there may be a cycle of abuse during which tensions rise and an act of violence is committed, followed by a period of reconciliation and calm. The victims may be trapped in domestically violent situations through isolation, power and control, traumatic bonding to the abuser, cultural acceptance, lack of financial resources, fear, and shame, or to protect children. As a result of abuse, victims may experience physical disabilities, dysregulated aggression, chronic health problems, mental illness, limited finances, and a poor ability to create healthy relationships. Victims may experience severe psychological disorders, such as post-traumatic stress disorder (PTSD). Children who live in a household with violence often show psychological problems from an early age, such as avoidance, hypervigilance to threats and dysregulated aggression, which may contribute to vicarious traumatization.
  • 9.6K
  • 21 Oct 2022
Topic Review
Progestin
A progestin is a type of medication which is used most commonly in hormonal birth control and menopausal hormone therapy. They can also be used in the treatment of gynecological conditions, to support fertility and pregnancy, to lower sex hormone levels for various purposes, and for other indications. Progestins are used alone or in combination with estrogens. They are available in a wide variety of formulations and for use by many different routes of administration. Side effects of progestins include menstrual irregularities, headaches, nausea, breast tenderness, mood changes, acne, increased hair growth, and changes in liver protein production among others. Other side effects of progestins include an increased risk of breast cancer, cardiovascular disease, and blood clots. At high dosages, progestins can cause low sex hormone levels and associated side effects like sexual dysfunction and an increased risk of bone fractures. Progestins are synthetic progestogens and have similar effects to those of the natural hormone progesterone. They act as agonists of the progesterone receptor, and have important effects in the female reproductive system (uterus, cervix, and vagina), the breasts, and the brain. In addition, many progestins also have other hormonal activities, such as androgenic, antiandrogenic, estrogenic, glucocorticoid, or antimineralocorticoid activity. They also have antigonadotropic effects and at sufficiently high dosages can strongly suppress sex hormone production. Progestins mediate their contraceptive effects both by inhibiting ovulation and by thickening cervical mucus, thereby preventing fertilization. They have functional antiestrogenic effects in certain tissues like the endometrium, and this underlies their use in menopausal hormone therapy. Progestins were first introduced for medical use in 1939. They started to be used in birth control in the 1950s. Around 60 progestins have been marketed for clinical use in humans or use in veterinary medicine. These progestins can be grouped into different classes and generations. Progestins are available widely throughout the world and are used in all forms of hormonal birth control and in most menopausal hormone therapy regimens.
  • 2.0K
  • 21 Oct 2022
Topic Review
V-twin Engine
A V-twin engine, also called a V2 engine, is a two-cylinder piston engine where the cylinders share a common crankshaft and are arranged in a V configuration. Although widely associated with motorcycles (installed either transversely or longitudinally), V-twin engines have also been used for industrial engines and in several small cars. The V-twin design dates back to the late 1880s.
  • 13.6K
  • 21 Oct 2022
Topic Review
European Single Market
The European Single Market, Internal Market or Common Market is a single market comprising the 27 member states of the European Union (EU) as well as – with certain exceptions – Iceland, Liechtenstein, and Norway through the Agreement on the European Economic Area, and Switzerland through bilateral treaties. The single market seeks to guarantee the free movement of goods, capital, services, and people, known collectively as the "four freedoms". A number of potential EU accession candidates have Stabilisation and Association Agreements with the EU, which allow for limited participation in selected sectors of the Single Market, including Albania, Bosnia and Herzegovina, Kosovo, Montenegro, North Macedonia, and Serbia. In addition, through three individual agreements on a Deep and Comprehensive Free Trade Area (DCFTA) with the EU, the post-Soviet countries of Georgia, Moldova, and Ukraine have also been granted limited access to the Single Market in selected sectors. Turkey has access to the free movement of some goods via its membership in the European Union–Turkey Customs Union. The United Kingdom left the European Single Market on 31 December 2020. An agreement was reached between the UK Government and European Commission to align Northern Ireland on rules for goods with the European Single Market, to maintain an open border on the island of Ireland. The market is intended to increase competition, labour specialisation, and economies of scale, allowing goods and factors of production to move to the area where they are most valued, thus improving the efficiency of the allocation of resources. It is also intended to drive economic integration whereby the once separate economies of the member states become integrated within a single EU-wide economy. The creation of the internal market as a seamless, single market is an ongoing process, with the integration of the service industry still containing gaps. According to a 2019 estimate, because of the single market the GDP of member countries is on average 9 percent higher than it would be if tariff and non-tariff restrictions were in place.
  • 2.2K
  • 21 Oct 2022
Topic Review
Surface-Extended X-Ray Absorption Fine Structure
Surface-extended X-ray absorption fine structure (SEXAFS) is the surface-sensitive equivalent of the EXAFS technique. This technique involves the illumination of the sample by high-intensity X-ray beams from a synchrotron and monitoring their photoabsorption by detecting in the intensity of Auger electrons as a function of the incident photon energy. Surface sensitivity is achieved by the interpretation of data depending on the intensity of the Auger electrons (which have an escape depth of ~1–2 nm) instead of looking at the relative absorption of the X-rays as in the parent method, EXAFS. The photon energies are tuned through the characteristic energy for the onset of core level excitation for surface atoms. The core holes thus created can then be filled by nonradiative decay of a higher-lying electron and communication of energy to yet another electron, which can then escape from the surface (Auger emission). The photoabsorption can therefore be monitored by direct detection of these Auger electrons to the total photoelectron yield. The absorption coefficient versus incident photon energy contains oscillations which are due to the interference of the backscattered Auger electrons with the outward propagating waves. The period of this oscillations depends on the type of the backscattering atom and its distance from the central atom. Thus, this technique enables the investigation of interatomic distances for adsorbates and their coordination chemistry. This technique benefits from long range order not being required, which sometimes becomes a limitation in the other conventional techniques like LEED (about 10 nm). This method also largely eliminates the background from the signal. It also benefits because it can probe different species in the sample by just tuning the X-ray photon energy to the absorption edge of that species. Joachim Stöhr played a major role in the initial development of this technique.
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  • 24 Oct 2022
Topic Review
List of Aircraft in the Smithsonian Institution
The List of aircraft in the Smithsonian Institution includes aircraft exhibited in the Smithsonian Institution's National Air and Space Museum, Steven F. Udvar-Hazy Center, and the Paul E. Garber Preservation, Restoration, and Storage Facility. The Smithsonian Institution's collection of aircraft and spacecraft is the largest on display in the world.
  • 3.8K
  • 21 Oct 2022
Topic Review
Dan Role
Dan is the general name for female roles in Chinese opera, often referring to leading roles. They may be played by male or female actors. In the early years of Peking opera, all dan roles were played by men, but this practice is no longer common in any Chinese opera genre.
  • 3.3K
  • 21 Oct 2022
Topic Review
Felicia (Genus)
Felicia is a genus of small shrubs, perennial or annual herbaceous plants, with 85 known species, that is assigned to the daisy family (Compositae or Asteraceae). Like in almost all Asteraceae, the individual flowers are 5-merous, small and clustered in typical heads, and which are surrounded by an involucre of, in this case between two and four whorls of, bracts. In Felicia, the centre of the head is taken by yellow, seldomly whitish or blackish blue disc florets, and is almost always surrounded by one single whorl of mostly purple, sometimes blue, pink, white or yellow ligulate florets and rarely ligulate florets are absent. These florets sit on a common base (or receptacle) and are not individually subtended by a bract (or palea). Most species occur in the Cape Floristic Region, which is most probably the area where the genus originates and had most of its development. Some species can be found in the eastern half of Africa up to Sudan and the south-western Arabian peninsula, while on the west coast species can be found from the Cape to Angola and one species having outposts on the Cameroon-Nigeria border and central Nigeria. Some species of Felicia are cultivated as ornamentals and several hybrids have been developed for that purpose.
  • 2.1K
  • 21 Oct 2022
Topic Review
Eidetic Imagery
An eidetic image is a type of vivid mental image, not necessarily derived from an actual external event or memory. It was identified in the early twentieth century as a distinct phenomenon by psychologists including E.R. Jaensch, Heinrich Klüver, Gordon Allport and Frederic Bartlett. Later, Akhter Ahsen located eidetic imagery in a structuralist context, and explored its therapeutic applications: psychotherapists sometimes encourage their clients to create and explore eidetic images as a way of coming to terms with past life events. Eidetic imagery has also been studied in relation to the creative arts.
  • 3.2K
  • 21 Oct 2022
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