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Topic Review
Sine
In mathematics, the sine is a trigonometric function of an angle. The sine of an acute angle is defined in the context of a right triangle: for the specified angle, it is the ratio of the length of the side that is opposite that angle, to the length of the longest side of the triangle (the hypotenuse). For an angle [math]\displaystyle{ x }[/math], the sine function is denoted simply as [math]\displaystyle{ \sin x }[/math]. More generally, the definition of sine (and other trigonometric functions) can be extended to any real value in terms of the length of a certain line segment in a unit circle. More modern definitions express the sine as an infinite series, or as the solution of certain differential equations, allowing their extension to arbitrary positive and negative values and even to complex numbers. The sine function is commonly used to model periodic phenomena such as sound and light waves, the position and velocity of harmonic oscillators, sunlight intensity and day length, and average temperature variations throughout the year. The function sine can be traced to the jyā and koṭi-jyā functions used in Gupta period Indian astronomy (Aryabhatiya, Surya Siddhanta), via translation from Sanskrit to Arabic, and then from Arabic to Latin. The word "sine" (Latin "sinus") comes from a Latin mistranslation by Robert of Chester of the Arabic jiba, which is a transliteration of the Sanskrit word for half the chord, jya-ardha.
  • 6.3K
  • 11 Oct 2022
Topic Review
Vascular Endothelial Growth Factors
Vascular endothelial growth factors (VEGFs) are primary regulators of blood and lymphatic vessels. Hemangiogenic VEGFs (VEGF-A, PlGF, and VEGF-B) target mostly blood vessels, while the lymphangiogenic VEGFs (VEGF-C and VEGF-D) target mostly lymphatic vessels. Blocking VEGF-A is used today to treat several types of cancer (“antiangiogenic therapy”). However, in other diseases, it would be beneficial to do the opposite, namely to increase the activity of VEGFs. For example, VEGF-A could generate new blood vessels to protect from heart disease, and VEGF-C could generate new lymphatics to counteract lymphedema. Clinical trials that tried to stimulate blood vessel growth in ischemic diseases have been disappointing so far, and the first clinical trials targeting the lymphatic vasculature have progressed to phase II. Antiangiogenic drugs targeting VEGF-A such as bevacizumab or aflibercept neutralize the growth factor directly. However, since VEGF-C and VEGF-D are produced as inactive precursors, novel drugs against the lymphangiogenic VEGFs could also target the enzymatic activation of VEGF-C and VEGF-D. Because of the delicate balance between too much and too little vascular growth, a detailed understanding of the activation of the VEGF-C and VEGF-D is needed before such concepts can be converted into safe and efficacious therapies.
  • 6.3K
  • 30 Mar 2021
Topic Review
Learning Styles
Learning styles refer to a range of competing and debunked theories that aim to account for differences in individuals' learning. Many theories share the proposition that humans can be classified according to their 'style' of learning, but differ in how the proposed styles should be defined, categorized and assessed.:8 A common concept is that individuals differ in how they learn.:266 The idea of individualized learning styles became popular in the 1970s, and has greatly influenced education despite the criticism that the idea has received from some researchers.:107–108 Proponents recommend that teachers have to run a needs analysis to assess the learning styles of their students and adapt their classroom methods to best fit each student's learning style. Although there is ample evidence that individuals express personal preferences for how they prefer to receive information,:108 few studies have found any validity in using learning styles in education.:267 Critics say there is no consistent evidence that identifying an individual student's learning style and teaching for specific learning styles produces better student outcomes.:33 Since 2012, Learning Styles have often been referred to as a "neuromyth" in education. There is evidence of empirical and pedagogical problems related to forcing learning tasks to "correspond to differences in a one-to-one fashion". Studies contradict the widespread "meshing hypothesis" that a student will learn best if taught in a method deemed appropriate for the student's learning style. However, a 2020 systematic review suggested that a majority (89%) of educators around the world continue to believe that the meshing hypothesis is correct. Studies further show that teachers cannot assess the learning style of their students accurately.
  • 6.3K
  • 02 Nov 2022
Topic Review
Electrospinning
Relative to many other nanofiber formation techniques, the electrospinning technique exhibits superior nanofiber formation when considering cost and manufacturing complexity for many situations. Aligned electrospun nanofibers have applications in nanocomposite structures and energy storage devices in addition to applications like air filtration, desalination, tissue engineering, textiles etc. The  specific strength and dielectric constant are important to understand mechanical and dielectric properties of electrospun fibers and tailor these properties in the field of composite and energy applications. 
  • 6.3K
  • 20 Jan 2021
Topic Review
Binary Fission
Fission, in biology, is the division of a single entity into two or more parts and the regeneration of those parts to separate entities resembling the original. The object experiencing fission is usually a cell, but the term may also refer to how organisms, bodies, populations, or species split into discrete parts. The fission may be binary fission, in which a single organism produces two parts, or multiple fission, in which a single entity produces multiple parts.
  • 6.3K
  • 31 Oct 2022
Topic Review
Fruit Vinegar Production
The production of fruit vinegars as a way of making use of fruit by-products is an option widely used by the food industry, since surplus or second quality fruit can be used without compromising the quality of the final product. The acetic nature of vinegars and its subsequent impact on the organoleptic properties of the final product allows almost any type of fruit to be used for its elaboration.
  • 6.3K
  • 13 May 2021
Topic Review
48,XXXY Syndrome
48,XXXY syndrome is a chromosomal condition in boys and men that causes intellectual disability, developmental delays, physical differences, and an inability to father biological children (infertility). Its signs and symptoms vary among affected individuals.
  • 6.3K
  • 23 Dec 2020
Topic Review
The White Sea
The White Sea is a small shallow semi-closed sea in the North-West of Russia. It is strongly affected by induced tides, so the tidal motion dominates in the sea. Sea ice is seasonal and the water salinity is less than in the neighbouring Barents sea due to strong river discharge. In this entry, we focus on the sources of data on the Sea.
  • 6.3K
  • 21 Jan 2021
Topic Review
Kübler-Ross Model
The Kübler-Ross model, or the Five Stages of Grief, postulates a series of emotions experienced by terminally ill patients prior to death, or people who have lost a loved one, wherein the five stages are: denial, anger, bargaining, depression, and acceptance. Although commonly referenced in popular media, the existence of these stages has not been empirically demonstrated and the model is not considered helpful in explaining the grieving process. It is considered to be of historical value but outdated in scientific terms and in clinical practice. The model was first introduced by Swiss-American psychiatrist Elisabeth Kübler-Ross in her 1969 book On Death and Dying, and was inspired by her work with terminally ill patients. Motivated by the lack of instruction in medical schools on the subject of death and dying, Kübler-Ross examined death and those faced with it at the University of Chicago's medical school. Kübler-Ross's project evolved into a series of seminars which, along with patient interviews and previous research, became the foundation for her book. Although Kübler-Ross is commonly credited with creating stage models, earlier bereavement theorists and clinicians such as Erich Lindemann, Collin Murray Parkes, and John Bowlby used similar models of stages of phases as early as the 1940s. Later in her life, Kübler-Ross noted that the stages are not a linear and predictable progression and that she regretted writing them in a way that was misunderstood. "Kübler-Ross originally saw these stages as reflecting how people cope with illness and dying," observed grief researcher Kenneth J. Doka, "not as reflections of how people grieve."
  • 6.3K
  • 03 Nov 2022
Topic Review
Iranian Subsidy Reform Plan
The economy of Iran includes a lot of subsidies. The Iranian targeted subsidy plan (Persian: طرح هدفمندسازی یارانه‌ها‎), also known as the subsidy reform plan, was passed by the Iranian Parliament in 2010. The government described the subsidy plan as the "biggest surgery" to the nation's economy in half a century and "one of the most important undertakings in Iran's recent economic history". The goal of the subsidy reform plan is to replace subsidies on food and energy (80% of total) with targeted social assistance, in accordance with a Five Year Economic Development Plan and a move towards free market prices in a 5-year period. The subsidy reform plan is the most important part of a broader Iranian economic reform plan. According to the government, approximately $100 billion per year is spent on subsidizing energy prices ($45 billion for the prices of fuel alone) and many consumable goods including bread, sugar, rice, cooking oil and medicine. However, some experts believe direct subsidies are about $30 billion, depending on oil prices. The subsidy system has been inherited from the Iran–Iraq War era but was never abolished. Iran is one of the largest gasoline consumers in the world, ranking second behind the United States in consumption per car. The government subsidy reform has been years in the making, for reasons which are unclear. Iran's Supreme Leader has backed the government’s subsidy reform plan.
  • 6.2K
  • 13 Oct 2022
Topic Review
BMW 7 Series (E65)
The BMW E65 is the fourth generation of the BMW 7 Series range of full-size luxury sedans, and was produced from 2001 to 2008. The variants of the range are: The E65 was the first BMW vehicle to include the iDrive infotainment system, the new brand design language, active anti-roll bars, a 6-speed automatic transmission, an electronic smart Key (dispensing with the traditional metallic key), and night vision. The 760i model also utilised the world's first production V12 engine to use direct injection. In late 2008, the E65 7 Series was replaced by the 7 Series (F01).
  • 6.2K
  • 11 Nov 2022
Topic Review
Corynebacterium
Corynebacterium species are frequent constituents of the normal bacterial flora of the conjunctival sac and are common as well on human skin and mucous membranes and in the intestines.
  • 6.2K
  • 18 Mar 2021
Topic Review
BeiDou Navigation Satellite System
The BeiDou Navigation Satellite System (BDS) is a Chinese satellite navigation system. It consists of two separate satellite constellations. The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System and also known as BeiDou-1, consists of three satellites which since 2000 has offered limited coverage and navigation services, mainly for users in China and neighboring regions. Beidou-1 was decommissioned at the end of 2012. The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, became operational in China in December 2011 with a partial constellation of 10 satellites in orbit. Since December 2012, it has been offering services to customers in the Asia-Pacific region. In 2015, China started the build-up of the third generation BeiDou system (BeiDou-3) in the global coverage constellation. The first BDS-3 satellite was launched on 30 March 2015. As of January 2018, nine BeiDou-3 satellites have been launched. BeiDou-3 will eventually consist of 35 satellites and is expected to provide global services upon completion in 2020. When fully completed, BeiDou will provide an alternative global navigation satellite system to the United States owned Global Positioning System (GPS), and is expected to be more accurate than the GPS. It was claimed in 2016 that BeiDou-3 will reach millimeter-level accuracy (with post-processing), which is ten times more accurate than the finest level of GPS. According to China Daily, in 2015, fifteen years after the satellite system was launched, it was generating a turnover of $31.5 billion per annum for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp.
  • 6.2K
  • 29 Nov 2022
Topic Review
Problematic Smartphone Use
Problematic smartphone use (PSU) is defined as the inability to control the time spent on smartphones, which has long-term negative impacts on daily life. The use-and-gratifications approach is applied to smartphones and describes the extent to which users devote themselves to smartphones to obtain gratifications. These gratifications can be represented in the types of use (process, social, and habitual).
  • 6.2K
  • 05 May 2022
Topic Review
Innovative Technologies for Polyphenol Oxidase Inactivation
Polyphenol oxidase (PPO) catalyses the browning reaction during fruit processing and storage. It is considered a threat to clean labels and minimally processed fruit products. Unwanted changes in fruits’ appearance and quality represent a cost to the industry. High pressure and ultrasound, in addition to thermal treatment, are effective in reducing PPO activity and producing high-quality products. PPO from different fruit cultivars behaves differently when submitted to different treatments.
  • 6.2K
  • 24 Mar 2022
Topic Review
Electrocommunication
Electrocommunication is the communication method used by weakly-electric fish. Weakly-electric fish are a group of animals that utilize a communicating channel that is "invisible" to most other animals: electric signaling. Electric fish communicate by generating an electric field that a second individual receives with its electroreceptors. The fish interprets the message using the signal's frequencies, waveforms, delay, etc. The best studied species are two freshwater lineages- the African Mormyridae and the South American Gymnotiformes. While weakly-electric fish are the only group that have been identified to carry out both generation and reception of electric fields, other species either generate signals or receive them, but not both. Animals that either generate or receive electric fields are found only in wet or aquatic environments due to water's relatively low electrical resistance, compared to other substances (e.g. air). So far, communication between electric fish has been identified mainly to serve the purpose of conveying information such as: species courtship and biological sex motivational status (e.g. attack warning, submission, etc.) environmental conditions
  • 6.2K
  • 31 Oct 2022
Topic Review
One-Dimensional (1D) Nanostructured Materials
At present, the world is at the peak of production of traditional fossil fuels. Much of the resources that humanity has been consuming (oil, coal, and natural gas) are coming to an end. The human being faces a future that must necessarily go through a paradigm shift, which includes a progressive movement towards increasingly less polluting and energetically viable resources. In this sense, nanotechnology has a transcendental role in this change. For decades, new materials capable of being used in energy processes have been synthesized, which undoubtedly will be the cornerstone of the future development of the planet.
  • 6.2K
  • 23 Jun 2021
Topic Review
Materials Science, Glasses
Glasses are solid amorphous materials which transform into liquids upon heating through the glass transition. The International Commission on Glass defines glass as a state of matter, usually produced when a viscous molten material is cooled rapidly to below its glass transition temperature, with insufficient time for a regular crystal lattice to form. The solid-like behaviour of glasses is separated from the liquid-like behaviour at higher temperatures by the glass transition temperature, Tg. The IUPAC Compendium on Chemical Terminology defines glass transition as a second order transition in which a supercooled melt yields, on cooling, a glassy structure. It states that below the glass-transition temperature the physical properties of glasses vary in a manner similar to those of the crystalline phase. Moreover, it is deemed that the bonding structure of glasses has the same symmetry signature in terms of Hausdorff-Besikovitch dimensionality of chemical bonds as for the crystalline materials. 
  • 6.2K
  • 09 May 2024
Topic Review
Traditional Mexican Diet
Grains, legumes, and vegetables were the most representative food groups in the traditional Mexican diet (TMexD), as these were mentioned in most (75%) of the studies, including all the subgroups evaluated. Additionally, maize (mostly as tortillas), beans, squash, tomato, chile, and onion are potentially fundamental elements of the TMexD, as these were the only individual foods cited in most studies, including all the subgroups evaluated. Indeed, maize (a grain), beans (a legume), and squash (a vegetable) have long represented the basic foods in Mexico, as they form part of the ancient agro-ecosystem known as Milpa. Other groups that were also mentioned in all the studies and subgroup analyses were maize products, fruits, beverages, fish and seafood, meats, sweets and sweeteners, and herbs and condiments. However, these were mentioned in different frequencies in the different subgroups assessed (i.e., in ≥75% of studies in some subgroups while in only 50% of studies in others). 
  • 6.2K
  • 05 Aug 2021
Topic Review
Islamic Primary Schools in the Netherlands
Because of the constitutional Freedom of education in the Netherlands, everyone can establish a school and is entitled to full state funding. There now are 52 primary Islamic schools, with around 12,500 pupils mostly of Turkish and Moroccan descent. They focus on developing an Islamic religious identity, and high educational quality and pupil achievement. Because most pupils come from socioeconomic disadvantaged backgrounds, the schools receive nearly twice as much budget than schools with a predominantly non-disadvantaged population. The existence of Islamic schools has always been controversial. Their output in terms of academic achievement is relatively high, however. In an absolute sense they achieve below the “average” Dutch school, but when compared with schools with the same disadvantaged pupil population, they achieve better. Lately, there have been problems with secondary Islamic schools in the Netherlands. As a result, several politicians propose to abolish the Freedom of education act.  
  • 6.2K
  • 03 Nov 2020
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