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Topic Review
Complement (Set Theory)
In set theory, the complement of a set A, often denoted by Ac (or A′), is the set of elements not in A. When all sets in the universe, i.e. all sets under consideration, are considered to be members of a given set U, the absolute complement of A is the set of elements in U that are not in A. The relative complement of A with respect to a set B, also termed the set difference of B and A, written [math]\displaystyle{ B \setminus A, }[/math] is the set of elements in B that are not in A.
  • 13.3K
  • 28 Nov 2022
Topic Review
History of Measurement
The earliest recorded systems of weights and measures originate in the 3rd or 4th millennium BC. Even the very earliest civilizations needed measurement for purposes of agriculture, construction, and trade. Early standard units might only have applied to a single community or small region, with every area developing its own standards for lengths, areas, volumes and masses. Often such systems were closely tied to one field of use, so that volume measures used, for example, for dry grains were unrelated to those for liquids, with neither bearing any particular relationship to units of length used for measuring cloth or land. With development of manufacturing technologies, and the growing importance of trade between communities and ultimately across the Earth, standardized weights and measures became critical. Starting in the 18th century, modernized, simplified and uniform systems of weights and measures were developed, with the fundamental units defined by ever more precise methods in the science of metrology. The discovery and application of electricity was one factor motivating the development of standardized internationally applicable units.
  • 13.2K
  • 03 Nov 2022
Topic Review
Mapogo Lion Coalition
The Mapogo lion coalition was a band of male South African lions that controlled the Sabi Sand region in Kruger National Park. The coalition became infamous for their sheer power and strength in taking over and dominating an area of approximately 70,000 ha (170,000 acres). It is believed the Mapogos killed in excess of 100 lions and cubs in a little over a year. The statistics may be higher given their coverage of such large territories. At its peak, the coalition consisted of six males - the leader Makulu (also spelled as Makhulu), Rasta, Scar, Pretty Boy, Kinky Tail and Mr. T.
  • 13.1K
  • 09 Oct 2022
Topic Review
Ali in the Quran
The majority of Islamic commentators do not believe that Ali ibn Abu Talib (Arabic: عَـلِي ابْـن أَبُـو طَـالِـب) is mentioned explicitly in the Quran. However, Shi'ite scholars and some Sunni scholars interpret many Quranic verses as referring to Ali. Shi'ite scholars also believe other Imams have been referred in the Quran. They believe Imams are referred to as "the signs of Allah, the way, the straight path, the light of Allah, the inheritors of the Book, the people of knowledge, the holders of authority and other such designations," Shi'ite sources state, Muhammad al-Baqir answers: "Allah revealed Salat to his Prophet but never said of three or four Rakats, revealed Zakat but did not mention to its details, revealed Hajj but did not count its Tawaf and the Prophet interpreted their details. Allah revealed this verse and Prophet said this verse is about Ali, Hasan, Husayn and the other Twelve Imams." Shi'ite scholars, thus, have argued that a quarter of Qur'anic verses are stating the station of imams. Such a view is rejected by Sunni scholars, who argue that some of these verses instead refer to the Quraysh or Muhammad's wives.
  • 13.1K
  • 14 Oct 2022
Topic Review
Nasolabial Angle in Orthodontic Diagnosis
The nasolabial angle (NLA) is one of the key factors to be studied in an orthodontic diagnosis for the aesthetics of the nose and facial profile.
  • 13.1K
  • 06 Feb 2022
Topic Review
Process of Converting Ammonia to Hydrogen
Hydrogen technology for transition to a hydrogen-based economy requires supplying clean and renewable energy and capture of CO2 from current fossil hydrogen production. Ammonia is the most popular substance as a green hydrogen carrier because it does not carry carbon, and the total hydrogen content of ammonia is higher than other fuels and is thus suitable to convert to hydrogen. Ammonia cracking is a process of producing hydrogen from ammonia decomposition over a catalyst at high temperatures and is preferentially performed at normal pressures. 
  • 13.0K
  • 12 Dec 2022
Topic Review
Energy Management Strategy
A Comprehensive Review on Classification, Energy Management Strategy, and Control Algorithm for Hybrid Electric Vehicles
  • 13.0K
  • 22 Oct 2020
Topic Review
Guilt-shame-fear Spectrum of Cultures
In cultural anthropology, the distinction between a guilt society (or guilt culture), shame society (also shame culture or honor-shame culture), and a fear society (or culture of fear) has been used to categorize different cultures. The differences can apply to how behavior is governed with respect to government laws, business rules, or social etiquette. This classification has been applied especially to so called "apollonian" societies, sorting them according to the emotions they use to control individuals (especially children) and maintaining social order, swaying them into norm obedience and conformity. The terminology was popularized by Ruth Benedict in The Chrysanthemum and the Sword, who described American culture as a "guilt culture" and Japanese culture as a "shame culture".
  • 12.9K
  • 04 Nov 2022
Topic Review
List of Oxidation States of the Elements
This is a list of known oxidation states of the chemical elements, excluding nonintegral values. The most common states appear in bold. The table is based on that of Greenwood and Earnshaw, with additions noted. Oxidation state 0, which occurs for all elements, is implied by the column with the symbol of the element. The format of the table, which was devised by Dmitri Mendeleev in 1889, shows the periodicity of the oxidation states of the elements.
  • 12.9K
  • 18 Oct 2022
Topic Review
Renewable Energy Supply Chain
The renewable energy supply chain (RESC) is defined as “the transformation of raw energy into usable energy and involves an effective set of management principles from the point of acquisition of energy resources to the point of consumption of usable energy”.
  • 12.9K
  • 16 Feb 2021
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