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Topic Review
Ton 618
Coordinates: 12h 28m 24.97s, +31° 28′ 37.7″ Ton 618 is a hyperluminous, broad-absorption-line, radio-loud quasar and Lyman-alpha blob located near the border of the constellations Canes Venatici and Coma Berenices, with the projected comoving distance of approximately 18.2 billion light-years from Earth. It possesses one of the most massive black holes ever found, with a mass of 66 billion M☉.
  • 39.0K
  • 24 Nov 2022
Topic Review
Arginine Signaling and Cancer Metabolism
Arginine is an amino acid critically involved in multiple cellular processes including the syntheses of nitric oxide and polyamine, and is a direct activator of mTOR, a nutrient sensing kinase strongly implicated in carcinogenesis. In this review, we will discuss arginine as a signaling metabolite, arginine’s role in cancer metabolism, arginine as an epigenetic regulator, arginine as an immunomodulator, and arginine as a therapeutic target. The different cell killing mechanisms associated with various cancer types will also be described.
  • 37.0K
  • 23 Feb 2023
Topic Review
Applications of Wireless Sensor Networks
A Wireless Sensor Network (WSN) is a group of spatially dispersed sensor nodes, which are interconnected by using wireless communication. The purpose of this entry is to provide an up-to-date presentation of both traditional and most recent applications of WSNs and hopefully not only enable the comprehension of this scientific area but also facilitate the perception of novel applications.
  • 36.5K
  • 28 Mar 2022
Topic Review
List of Topics Characterized as Pseudoscience
This is a list of topics that have, either currently or in the past, been characterized as pseudoscience by academics or researchers. Detailed discussion of these topics may be found on their main pages. These characterizations were made in the context of educating the public about questionable or potentially fraudulent or dangerous claims and practices—efforts to define the nature of science, or humorous parodies of poor scientific reasoning. Criticism of pseudoscience, generally by the scientific community or skeptical organizations, involves critiques of the logical, methodological, or rhetorical bases of the topic in question. Though some of the listed topics continue to be investigated scientifically, others were only subject to scientific research in the past and today are considered refuted, but resurrected in a pseudoscientific fashion. Other ideas presented here are entirely non-scientific, but have in one way or another impinged on scientific domains or practices. Many adherents or practitioners of the topics listed here dispute their characterization as pseudoscience. Each section here summarizes the alleged pseudoscientific aspects of that topic.
  • 36.3K
  • 14 Oct 2022
Topic Review
Black Soldier Fly
The black soldier fly (BSF), Hermetia illucens Linnaeus, is a large Stratiomyidae fly (13-20 mm in size) found worldwide, but it is believed to have originated in the Americas. It is frequently found in the tropics and temperate regions throughout the world. Although adapted primarily to these regions, it can tolerate wide extremes of temperature except when ovipositing. They are considered beneficial insects and non-pests. The adult fly does not have mouthparts, stingers, or digestive organs; thus, they do not bite or sting and do not feed during its short lifespan. They feed only as larvae and are, therefore, not associated with disease transmission. BSF larvae (BSFL) are voracious eaters of a wide range of organic wastes, decomposing and returning nutrients to the soil. Additionally, BSFL is an alternative protein source for aquaculture, pet food, livestock feed, and human nutrition.
  • 35.4K
  • 25 Apr 2023
Topic Review
Drinking the Kool-Aid
"Drinking the Kool-Aid" is an expression used to refer to a person who believes in a possibly doomed or dangerous idea because of perceived potential high rewards. The phrase often carries a negative connotation. It can also be used ironically or humorously to refer to accepting an idea or changing a preference due to popularity, peer pressure, or persuasion. In recent years it has evolved further to mean extreme dedication to a cause or purpose, so extreme that one would "drink the Kool-Aid" and die for the cause. The phrase originates from events in Jonestown, Guyana, on November 18, 1978, in which over 900 members of the Peoples Temple movement died. The movement's leader, Jim Jones, called a mass meeting at the Jonestown pavilion after the murder of U.S. Congressman Leo Ryan and others in nearby Port Kaituma. Jones proposed "revolutionary suicide" by way of ingesting a powdered drink mix lethally laced with cyanide and other drugs which had been prepared by his aides.
  • 35.0K
  • 23 Nov 2022
Topic Review
Space Vector PWM Techniques
This entry elaborates the basic concept of space vector Pulse Width modulation technique for a three-phase voltage source inverter. Why space vector Pulse width modulation (PWM) is required and how it is implemented in the simulation model, is described in the entry.  A number of PWM scheme is used to obtain variable voltage and frequency supply from a power converter. The most widely used PWM schemes for three-phase voltage source inverter (VSI) are carrier-based sinusoidal PWM and space vector PWM (SVPWM). There is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization and better dc bus utilization. This entry focuses on step by step development of MATLAB/SIMULINK model of SVPWM. Firstly the model of a three-phase VSI is discussed based on space vector representation. Next simulation model of SVPWM is obtained using MATLAB/SIMULINK. Simulation results are also provided. 
  • 34.0K
  • 16 Jun 2022
Topic Review
Polar Moment of Inertia
The polar moment (of inertia), also known as second (polar) moment of area, is a quantity used to describe resistance to torsional deformation (deflection), in cylindrical (or non-cylindrical) objects (or segments of an object) with an invariant cross-section and no significant warping or out-of-plane deformation. It is a constituent of the second moment of area, linked through the perpendicular axis theorem. Where the planar second moment of area describes an object's resistance to deflection (bending) when subjected to a force applied to a plane parallel to the central axis, the polar second moment of area describes an object's resistance to deflection when subjected to a moment applied in a plane perpendicular to the object's central axis (i.e. parallel to the cross-section). Similar to planar second moment of area calculations ([math]\displaystyle{ I_x }[/math],[math]\displaystyle{ I_y }[/math], and [math]\displaystyle{ I_{xy} }[/math]), the polar second moment of area is often denoted as [math]\displaystyle{ I_z }[/math]. While several engineering textbooks and academic publications also denote it as [math]\displaystyle{ J }[/math] or [math]\displaystyle{ J_z }[/math], this designation should be given careful attention so that it does not become confused with the torsion constant, [math]\displaystyle{ J_t }[/math], used for non-cylindrical objects. Simply put, the polar moment of inertia is a shaft or beam's resistance to being distorted by torsion, as a function of its shape. The rigidity comes from the object's cross-sectional area only, and does not depend on its material composition or shear modulus. The greater the magnitude of the polar moment of inertia, the greater the torsional resistance of the object.
  • 33.8K
  • 14 Nov 2022
Topic Review
Language Acquisition
Language acquisition is the process by which humans acquire the capacity to perceive and comprehend language (in other words, gain the ability to be aware of language and to understand it), as well as to produce and use words and sentences to communicate. Language acquisition involves structures, rules and representation. The capacity to successfully use language requires one to acquire a range of tools including phonology, morphology, syntax, semantics, and an extensive vocabulary. Language can be vocalized as in speech, or manual as in sign. Human language capacity is represented in the brain. Even though human language capacity is finite, one can say and understand an infinite number of sentences, which is based on a syntactic principle called recursion. Evidence suggests that every individual has three recursive mechanisms that allow sentences to go indeterminately. These three mechanisms are: relativization, complementation and coordination. There are two main guiding principles in first-language acquisition: speech perception always precedes speech production and the gradually evolving system by which a child learns a language is built up one step at a time, beginning with the distinction between individual phonemes. Linguists who are interested in child language acquisition for many years question how language is acquired, Lidz et al. states "The question of how these structures are acquired, then, is more properly understood as the question of how a learner takes the surface forms in the input and converts them into abstract linguistic rules and representations." Language acquisition usually refers to first-language acquisition, which studies infants' acquisition of their native language, whether that be spoken language or signed language as a result of prelingual deafness, though it can also refer to bilingual first language acquisition (BFLA), which refers to an infant's simultaneous acquisition of two native languages. This is distinguished from second-language acquisition, which deals with the acquisition (in both children and adults) of additional languages. In addition to speech, reading and writing a language with an entirely different script compounds the complexities of true foreign language literacy. Language acquisition is one of the quintessential human traits, because non-humans do not communicate by using language.
  • 32.5K
  • 18 Nov 2022
Topic Review
Harut and Marut
Harut and Marut (Arabic: هَارُوْت وَمَارُوْت) are two angels mentioned in Quran 2:102, who are said to have been located in Babylon. According to some narratives, those two angels were in the time of Idris. The Quran indicates that they were a trial for the people and through them the people were tested with sorcery. The story itself parallels a Jewish legend about the fallen angels Shemḥazaī, ʿUzza, and ʿAzaʾel. The names Hārūt and Mārūt appear to be etymologically related to those of Haurvatat and Ameretat, two Zoroastrian archangels. Haurvatat-Ameretat (Pahlavi hrwdʼd ʼmwrdʼd) appears in Sogdian language texts as hrwwt mrwwt. A relationship to Armenian hawrot mawrot has been suggested but is not confirmed. Muslim sources disagree, whether Harut and Marut can be considered fallen angels or not.
  • 31.8K
  • 15 Nov 2022
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