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Topic Review
Stress–Energy Tensor
The stress–energy tensor, sometimes called the stress–energy–momentum tensor or the energy–momentum tensor, is a tensor quantity in physics that describes the density and flux of energy and momentum in spacetime, generalizing the stress tensor of Newtonian physics. It is an attribute of matter, radiation, and non-gravitational force fields. This density and flux of energy and momentum are the sources of the gravitational field in the Einstein field equations of general relativity, just as mass density is the source of such a field in Newtonian gravity.
  • 8.2K
  • 23 Nov 2022
Topic Review
Socialist State
A socialist state, socialist republic, or socialist country, sometimes referred to as a workers' state or workers' republic, is a sovereign state constitutionally dedicated to the establishment of socialism. The term communist state is often used synonymously in the West specifically when referring to one-party socialist states governed by Marxist–Leninist communist parties, despite these countries being officially socialist states in the process of building socialism. These countries never describe themselves as communist nor as having implemented a communist society. Additionally, a number of countries that are multi-party capitalist states make references to socialism in their constitutions, in most cases alluding to the building of a socialist society, naming socialism, claiming to be a socialist state, or including the term people's republic or socialist republic in their country's full name, although this does not necessarily reflect the structure and development paths of these countries' political and economic systems. Currently, these countries include Algeria, Bangladesh, Guyana, India, Nepal, Nicaragua, Portugal, Sri Lanka and Tanzania. The idea of a socialist state stems from the broader notion of state socialism, the political perspective that the working class needs to use state power and government policy to establish a socialised economic system. This may either mean a system where the means of production, distribution and exchange are nationalised or under state ownership, or simply a system in which social values or workers' interests have economic priority. However, the concept of a socialist state is mainly advocated by Marxist–Leninists and most socialist states have been established by political parties adhering to Marxism–Leninism or some national variation thereof such as Maoism, Stalinism or Titoism. A state, whether socialist or not, is opposed the most by anarchists, who reject the idea that the state can be used to establish a socialist society due to its hierarchical and arguably coercive nature, considering a socialist state or state socialism as an oxymoron. The concept of a socialist state is also considered unnecessary or counterproductive and rejected by some classical, libertarian and orthodox Marxists, libertarian socialists and other socialist political thinkers who view the modern state as a byproduct of capitalism which would have no function in a socialist system. A socialist state is to be distinguished from a multi-party liberal democracy governed by a self-described socialist party, where the state is not constitutionally bound to the construction of socialism. In such cases, the political system and machinery of government is not specifically structured to pursue the development of socialism. Socialist states in the Marxist–Leninist sense are sovereign states under the control of a vanguard party which is organizing the country's economic, political and social development toward the realization of socialism. Economically, this involves the development of a state capitalist economy with state-directed capital accumulation with the long-term goal of building up the country's productive forces while simultaneously promoting world communism. Academics, political commentators and other scholars tend to distinguish between authoritarian socialist and democratic socialist states, with the first representing the Soviet Bloc and the latter representing Western Bloc countries which have been democratically governed by socialist parties such as Britain, France, Sweden and Western social-democracies in general, among others.
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  • 24 Oct 2022
Topic Review
AMD Radeon Rx 200 Series
The AMD Radeon R5/R7/R9 200 series is a family of GPUs developed by AMD. These GPUs are manufactured on a 28 nm Gate-Last process through TSMC or Common Platform Alliance.
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  • 18 Oct 2022
Topic Review
SpaceX Mars Transportation Infrastructure
Elon Musk and SpaceX have proposed the development of Mars transportation infrastructure in order to facilitate the eventual colonization of Mars. The mission architecture includes fully reusable launch vehicles, human-rated spacecraft, on-orbit propellant tankers, rapid-turnaround launch/landing mounts, and local production of rocket fuel on Mars via in situ resource utilization (ISRU). SpaceX's aspirational goal since 2017 has been to land the first humans on Mars by 2024. A key element of the infrastructure is planned to be the SpaceX Starship, a fully reusable space vehicle under development since 2018. To achieve a large payload, the spacecraft would first enter Earth orbit, where it is expected to be refueled before it departs to Mars. After landing on Mars, the spacecraft would be loaded with locally-produced propellants to return to Earth. The expected payload for the Starship/Super Heavy is to inject between 100–150 tonnes (220,000–330,000 lb) to Mars. SpaceX intends to concentrate its resources on the transportation part of the Mars colonization project, including the design of a propellant plant based on the Sabatier process that will be deployed on Mars to synthesize methane and liquid oxygen as rocket propellants from the local supply of atmospheric carbon dioxide and ground-accessible water ice. However, Musk has advocated since 2016 a larger set of long-term Mars settlement objectives, going far beyond what SpaceX projects to build; any successful colonization would ultimately involve many more economic actors—whether individuals, companies, or governments—to facilitate the growth of the human presence on Mars over many decades.
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  • 21 Nov 2022
Topic Review
Celebrity Worship Syndrome
Celebrity worship syndrome (CWS) is an obsessive addictive disorder in which a person becomes overly involved with the details of a celebrity's personal and professional life. Psychologists have indicated that though many people obsess over film, television, sport and pop stars, the only common factor between them is that they are all figures in the public eye. Written observations of celebrity worship date back to the 19th century.
  • 8.1K
  • 17 Oct 2022
Biography
Shahid Khan
Shahid Khan (Urdu: شاہد خان‎; born July 18, 1950),[1][2] also known as Shad Khan, is a Pakistani-American billionaire businessman and philanthropist. He is the owner of the Jacksonville Jaguars of the National Football League (NFL) and Fulham F.C. of the English Premier League. Khan is also the owner of the automobile parts manufacturer Flex-N-Gate in Urbana, Illinois. Khan was feature
  • 8.1K
  • 30 Nov 2022
Topic Review
Adaptive Reuse of Architectural Heritage
       Significant architectural and historical monuments become an important point of reference for the local population, increasing their sense of security, and act as a factor shaping social identity. An effort to preserve relevant objects in a city is therefore important both for retaining its unique features and for strengthening the local community. A significant role plays here the adaptive reuse of architectural heritage, which allows for the preservation of architectural objects that are important to the local community, promoting the integrity and historical continuity of the city while restoring the objects’ functional and economic value.         The introduction of a new function in architectural heritage is not only an important impulse for the tangible regeneration of urban tissue, but can also help to reconstruct the image and identity of a city. The local cultural and architectural heritage plays a significant role in the process leading to the creation of positive references and elimination of negative connotations related to an economic or social crisis. These remain an important part of the history of a city and, at the same time, its significance may be reimagined and shown in a new context, that relates to the present day. As a result, artefacts of the past gain new meanings, which are subject to a different, contemporary interpretation through the prism of current needs and ideas. Objects or even groups of objects from the past are being consciously taken into consideration in the activities currently undertaken. The contemporary scale of the phenomenon and complexity of the issues concerning the adaptive reuse of architectural heritage are a consequence of the multi-faceted transformations that have taken place in recent decades in the social, cultural and economic spheres, and, consequently, the contemporary understanding of the role and significance of the architectural heritage.
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  • 31 Aug 2021
Topic Review
Ghauri (Missile)
The Ghauri–I (Urdu: غوری-ا‎; official codename: Hatf–5 Ghauri–I) is a land-based surface-to-surface medium-range ballistic missile, in current service with the Pakistan Army's Strategic Forces Command— a subordinate command of Strategic Plans Division. Influenced from the design of Nodong-1 of North Korea, its extensive modification and engineering took place in Kahuta Research Laboratories (KRL) in 1990s with an objective of developing an electronic system that uses a single stage liquid fuel rocket motor to carry a payload of 700 kg to a range of 1,500 km. This is enough to reach most, if not all of India. Two variants of the Ghauri were produced under the secretive missile research programme started in 1987 and the development of a third variant was cancelled. The Ghauri-II uses increased motor assembly length and improved propellants for an increased range of 2,300 km (1,400 mi). The missile is named after Shahabuddin Muhammad Ghauri, while the "Hatf" designation originates from the name of the sword or lance of the Islamic prophet Muhammad.
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  • 09 Nov 2022
Topic Review
Adolescence
Adolescence (from la adolescere 'to grow up') is a transitional stage of physical and psychological development that generally occurs during the period from puberty to legal adulthood (age of majority). Adolescence is usually associated with the teenage years, but its physical, psychological or cultural expressions may begin earlier and end later. For example, puberty now typically begins during preadolescence, particularly in females. Physical growth (particularly in males), and cognitive development can extend into the early twenties. Thus age provides only a rough marker of adolescence, and scholars have found it difficult to agree upon a precise definition of adolescence. A thorough understanding of adolescence in society depends on information from various perspectives, including psychology, biology, history, sociology, education, and anthropology. Within all of these perspectives, adolescence is viewed as a transitional period between childhood and adulthood, whose cultural purpose is the preparation of children for adult roles. It is a period of multiple transitions involving education, training, employment and unemployment, as well as transitions from one living circumstance to another. The end of adolescence and the beginning of adulthood varies by country. Furthermore, even within a single nation state or culture there can be different ages at which an individual is considered mature enough for society to entrust them with certain privileges and responsibilities. Such privileges and responsibilities include driving a vehicle, having legal sexual relations, serving in the armed forces or on a jury, purchasing and drinking alcohol, voting, entering into contracts, finishing certain levels of education, marriage, and accountability for upholding the law. Adolescence is usually accompanied by an increased independence allowed by the parents or legal guardians, including less supervision as compared to preadolescence. In studying adolescent development, adolescence can be defined biologically, as the physical transition marked by the onset of puberty and the termination of physical growth; cognitively, as changes in the ability to think abstractly and multi-dimensionally; or socially, as a period of preparation for adult roles. Major pubertal and biological changes include changes to the sex organs, height, weight, and muscle mass, as well as major changes in brain structure and organization. Cognitive advances encompass both increment in knowledge and in the ability to think abstractly and to reason more effectively. The study of adolescent development often involves interdisciplinary collaborations. For example, researchers in neuroscience or bio-behavioral health might focus on pubertal changes in brain structure and its effects on cognition or social relations. Sociologists interested in adolescence might focus on the acquisition of social roles (e.g., worker or romantic partner) and how this varies across cultures or social conditions. Developmental psychologists might focus on changes in relations with parents and peers as a function of school structure and pubertal status. Some scientists have questioned the universality of adolescence as a developmental phase, arguing that traits often considered typical of adolescents are not in fact inherent to the teenage years.
  • 8.1K
  • 12 Oct 2022
Topic Review
Temple of Confucius
A temple of Confucius or Confucian temple is a temple for the veneration of Confucius and the sages and philosophers of Confucianism in Chinese folk religion and other East Asian religions. They were formerly the site of the administration of the imperial examination in China, Korea, Japan and Vietnam and often housed schools and other studying facilities.
  • 8.1K
  • 18 Nov 2022
Topic Review
Fundamentals of Oxygen Reduction Reaction
Oxygen reduction reaction (ORR) has been the subject of huge investigation since it is at the heart of various energy conversion and storage systems such as fuel cells, metal-air batteries, and so on. The mechanistic pathway is governed not only by the oxygen adsorption mode, but it also depends on the dissociation barrier of the catalyst surface. 
  • 8.1K
  • 02 Sep 2022
Topic Review Peer Reviewed
Khosrow II (590–628 CE)
Khosrow II (r. 590–628 CE) was the last great Sasanian king who took the throne with the help of the Romans and broke with dynastic religious preferences as he became married to a Christian empress. It was under his rule that the Sasanian Empire reached its greatest expansion. From the standpoint of iconographic studies, Khosrow II is among the most influential Persian kings. Although he was literally occupied by rebels and wars within the borders of the Sasanian territories and beyond, Khosrow managed to create a powerful image of himself that emphasized the legitimacy of his monarchy. Indeed, Khosrow Parviz (the Victorious) drew upon royal iconography as a propaganda tool on a wide range of materials such as rock and stucco reliefs, coins, seals, and metal plates. His image (created both visually and verbally) not only revived the traditional iconography of the Persian kings but also evolved it in a way that transcended his time and was passed on to the early Islamic Caliphates after him. Khosrow II imitated and manipulated the traditional royal iconography of his predecessors in order to display his legitimacy, piety, and valor. 
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  • 17 May 2022
Topic Review
Pot-in-pot Refrigerator
A pot-in-pot refrigerator, clay pot cooler or zeer (Arabic: زير) is an evaporative cooling refrigeration device which does not use electricity. It uses a porous outer earthenware pot (lined with wet sand) containing an inner pot (which can be glazed to prevent penetration by the liquid) within which the food is placed. The evaporation of the outer liquid draws heat from the inner pot. The device can cool any substance, and requires only a flow of relatively dry air and a source of water.
  • 8.1K
  • 09 Oct 2022
Topic Review
Intelligent Tutoring System
An intelligent tutoring system (ITS) is a computer system that aims to provide immediate and customized instruction or feedback to learners, usually without requiring intervention from a human teacher. ITSs have the common goal of enabling learning in a meaningful and effective manner by using a variety of computing technologies. There are many examples of ITSs being used in both formal education and professional settings in which they have demonstrated their capabilities and limitations. There is a close relationship between intelligent tutoring, cognitive learning theories and design; and there is ongoing research to improve the effectiveness of ITS. An ITS typically aims to replicate the demonstrated benefits of one-to-one, personalized tutoring, in contexts where students would otherwise have access to one-to-many instruction from a single teacher (e.g., classroom lectures), or no teacher at all (e.g., online homework). ITSs are often designed with the goal of providing access to high quality education to each and every student.
  • 8.1K
  • 10 Oct 2022
Topic Review Peer Reviewed
Ferdinand II of Aragon (1479–1516)
Ferdinand II king of Aragon (1479–1516). He was the fourth king of the Trastámara dynasty, which had first come to power after the Compromise of Caspe, reached after Martin I died with no living descendants in 1410. Although in terms of artistic patronage Ferdinand II was not as active as his wife Elisabeth I, he was still aware that the wise use of artistic commissions in reinforcing ideas and concepts favourable to the institution of the monarchy. He is a highly important figure in the history of Spain because, along with Elisabeth, he was one of the Catholic Monarchs and thus represents a new conception of power based on their joint governance, a fact that is reflected in the iconography found in his artistic commissions across all genres. All of the images are evidence of how King Ferdinand, at the end of the Middle Ages, wanted to be recognised by his subjects, who also used his image for legitimising and propagandistic purposes. Nobody else in the history of the Hispanic kingdoms had their image represented so many times and on such diverse occasions as did the Catholic Monarchs.
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  • 13 Apr 2022
Topic Review
Petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that consist of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, mostly zooplankton and algae, are buried underneath sedimentary rock and subjected to both prolonged heat and pressure. Petroleum has mostly been recovered by oil drilling. Drilling is carried out after studies of structural geology, sedimentary basin analysis, and reservoir characterisation. Recent developments in technologies have also led to exploitation of other unconventional reserves such as oil sands and oil shale. Once extracted, oil is refined and separated, most easily by distillation, into numerous products for direct use or use in manufacturing, such as gasoline (petrol), diesel and kerosene to asphalt and chemical reagents used to make plastics, pesticides and pharmaceuticals. Petroleum is used in manufacturing a wide variety of materials, and it is estimated that the world consumes about 100 million barrels (16 million cubic metres) each day. Petroleum production can be extremely profitable and was important for economic development in the 20th century, with some countries, so called "oil states", gaining significant economic and international power because of their control of oil production. Petroleum exploitation has significant negative environmental and social consequences. Most significantly, extraction, refining and burning of petroleum fuels all release large quantities of greenhouse gases, so petroleum is one of the major contributors to climate change. Furthermore, parts of the petroleum industry actively suppressed science and policy that aimed to prevent the climate crisis. Other negative environmental effects include the environmental impacts of exploration and exploitation of petroleum reserves, such as oil spills, and air and water pollution at the sites of utilization. All of these environmental impacts have direct health consequences for humans. Additionally, oil has also been a source of conflict leading to both state-led-wars and other kinds of conflicts (for example, oil revenue funded the Islamic State). Production of petroleum is expected to reach peak oil before 2035 as global economies lower dependencies on petroleum as part of climate change mitigation and a transition towards renewable energy and electrification. This is expected to have significant economic impacts that stakeholders argue need to be anticipated by a just transition and addressing the stranded assets of the petroleum industry.
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  • 21 Oct 2022
Topic Review
Charging Technology for Battery Electric Buses
The charging infrastructure has a key role in the implementation of battery electric buses (BEBs) in cities. BEBs only use off-board chargers, whereas the PEC to convert the three-phase AC power from the grid into DC power to charge the battery is located outside the BEB. These chargers allow higher charging power levels because they are not restricted in size and weight. Furthermore, since the driving range of a BEB is limited, a specific charging concept and interface is required to keep the BEB running during the day. This entry gives an overview of the existing charging interfaces and concepts and charger and PEC topologies to provide a reliable and efficient charging behavior.
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  • 18 Nov 2021
Topic Review
Pre-Existence
Pre-existence, preexistence, beforelife, or premortal existence refers to the belief that each individual human soul existed before mortal conception, and at some point before birth enters or is placed into the body. Concepts of pre-existence can encompass either the belief that the soul came into existence at some time prior to conception or the belief that the soul is eternal. Alternative positions are traducianism and creationism, which both hold that the individual human soul does not come into existence until conception. It is to be distinguished from preformation, which is about physical existence and applies to all living things. Ancient Greek thought and Islam affirm pre-existence, but it is generally denied in Christianity.
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  • 08 Nov 2022
Topic Review
Hongdu L-15
The Hongdu L-15 Falcon (猎鹰) is a supersonic advanced training and light combat aircraft being developed by Nanchang-based Hongdu Aviation Industry Corporation (HAIC) to meet the Chinese People's Liberation Army Air Force (PLAAF) and People's Liberation Army Naval Air Force (PLANAF) lead-in fighter trainer (LIFT) requirements, as well as next-generation training and light combat needs for foreign customers.
  • 8.1K
  • 28 Nov 2022
Topic Review
Reflective Practice
Reflective practice is the ability to reflect on one's actions so as to engage in a process of continuous learning. According to one definition it involves "paying critical attention to the practical values and theories which inform everyday actions, by examining practice reflectively and reflexively. This leads to developmental insight". A key rationale for reflective practice is that experience alone does not necessarily lead to learning; deliberate reflection on experience is essential. Reflective practice can be an important tool in practice-based professional learning settings where people learn from their own professional experiences, rather than from formal learning or knowledge transfer. It may be the most important source of personal professional development and improvement. It is also an important way to bring together theory and practice; through reflection a person is able to see and label forms of thought and theory within the context of his or her work. A person who reflects throughout his or her practice is not just looking back on past actions and events, but is taking a conscious look at emotions, experiences, actions, and responses, and using that information to add to his or her existing knowledge base and reach a higher level of understanding.
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  • 14 Nov 2022
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