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Topic Review
History of Solar System Formation and Evolution Hypotheses
The history of scientific thought about the Formation and evolution of the Solar System begins with the Copernican Revolution. The first recorded use of the term "Solar System" dates from 1704.
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  • 22 Nov 2022
Topic Review
Hockey Stick Controversy
In the hockey stick controversy, the data and methods used in reconstructions of the temperature record of the past 1000 years have been disputed. Reconstructions have consistently shown that the rise in the instrumental temperature record of the past 150 years is not matched in earlier centuries, and the name "hockey stick graph" was coined for figures showing a long-term decline followed by an abrupt rise in temperatures. These graphs were publicised to explain the scientific findings of climatology, and in addition to scientific debate over the reconstructions, they have been the topic of political dispute. The issue is part of the global warming controversy and has been one focus of political responses to reports by the Intergovernmental Panel on Climate Change (IPCC). Arguments over the reconstructions have been taken up by fossil fuel industry–funded lobbying groups attempting to cast doubt on climate science. The use of proxy indicators to get quantitative estimates of the temperature record of past centuries was developed from the 1990s onwards, and found indications that recent warming was exceptional. The Bradley & Jones 1993 reconstruction introduced the "Composite Plus Scaling" (CPS) method used by most later large-scale reconstructions, and its findings were disputed by Patrick Michaels at the United States House Committee on Science. In 1998, Michael E. Mann, Raymond S. Bradley and Malcolm K. Hughes developed new statistical techniques to produce Mann, Bradley & Hughes 1998 (MBH98), the first eigenvector-based climate field reconstruction (CFR). This showed global patterns of annual surface temperature, and included a graph of average hemispheric temperatures back to 1400. In Mann, Bradley & Hughes 1999 (MBH99) the methodology was extended back to 1000. The term hockey stick was coined by the climatologist Jerry D. Mahlman, to describe the pattern this showed, envisaging a graph that is relatively flat to 1900 as forming an ice hockey stick's "shaft", followed by a sharp increase corresponding to the "blade". A version of this graph was featured prominently in the 2001 IPCC Third Assessment Report (TAR), along with four other reconstructions supporting the same conclusion. The graph was publicised, and became a focus of dispute for those opposed to the strengthening scientific consensus that late 20th-century warmth was exceptional. Those disputing the graph included Pat Michaels, the George C. Marshall Institute and Fred Singer. A paper by Willie Soon and Sallie Baliunas claiming greater medieval warmth was used by the Bush administration chief of staff Philip Cooney to justify altering the first Environmental Protection Agency Report on the Environment. The paper was quickly dismissed by scientists in the Soon and Baliunas controversy, but on July 28, Republican Jim Inhofe spoke in the Senate citing it to claim "that man-made global warming is the greatest hoax ever perpetrated on the American people". Later in 2003, a paper by Steve McIntyre and Ross McKitrick disputing the data used in MBH98 paper was publicised by the George C. Marshall Institute and the Competitive Enterprise Institute. In 2004, Hans von Storch published criticism of the statistical techniques as tending to underplay variations in earlier parts of the graph, though this was disputed and he later accepted that the effect was very small. In 2005, McIntyre and McKitrick published criticisms of the principal component analysis methodology as used in MBH98 and MBH99. The analysis therein was subsequently disputed by published papers, including Huybers 2005 and Wahl & Ammann 2007, which pointed to errors in the McIntyre and McKitrick methodology. In June 2005, Rep. Joe Barton launched what Sherwood Boehlert, chairman of the House Science Committee, called a "misguided and illegitimate investigation" into the data, methods and personal information of Mann, Bradley and Hughes. At Boehlert's request, a panel of scientists convened by the National Research Council was set up, which reported in 2006, supporting Mann's findings with some qualifications, including agreeing that there were some statistical failings but these had little effect on the result. Barton and U.S. Rep. Ed Whitfield requested Edward Wegman to set up a team of statisticians to investigate, and they supported McIntyre and McKitrick's view that there were statistical failings, although they did not quantify whether there was any significant effect. They also produced an extensive network analysis which has been discredited by expert opinion and found to have issues of plagiarism. Arguments against the MBH studies were reintroduced as part of the Climatic Research Unit email controversy, but dismissed by eight independent investigations. More than two dozen reconstructions, using various statistical methods and combinations of proxy records, have supported the broad consensus shown in the original 1998 hockey-stick graph, with variations in how flat the pre-20th century "shaft" appears. The 2007 IPCC Fourth Assessment Report cited 14 reconstructions, 10 of which covered 1,000 years or longer, to support its strengthened conclusion that it was likely that Northern Hemisphere temperatures during the 20th century were the highest in at least the past 1,300 years. Over a dozen subsequent reconstructions, including Mann et al. 2008 and PAGES 2k Consortium 2013, have supported these general conclusions.
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  • 21 Oct 2022
Topic Review
BMW X5 (E70)
The BMW E70 is the second-generation BMW X5 mid-size luxury crossover SUV. It replaced the BMW X5 (E53) in July 2006. It was manufactured alongside the BMW X6 at BMW's Greer, South Carolina plant in the U.S. and BMW's facility in Toluca, Mexico.
  • 7.5K
  • 29 Nov 2022
Topic Review
Minimalist Program
In linguistics, the minimalist program (MP) is a major line of inquiry that has been developing inside generative grammar since the early 1990s, starting with a 1993 paper by Noam Chomsky. Chomsky presents MP as a program, not as a theory, following Imre Lakatos's distinction. The MP seeks to be a mode of inquiry characterized by the flexibility of the multiple directions that its minimalism enables. Ultimately, the MP provides a conceptual framework used to guide the development of linguistic theory. In minimalism, Chomsky attempts to approach universal grammar from below—that is, proposing the question "what would be the optimal answer to what the theory of i-Language should be?" For Chomsky, there are minimalist questions, but the answers can be framed in any theory. Of all these questions, the two that play the most crucial role are:
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  • 20 Nov 2022
Topic Review
Beeswax
Beeswax is one of the natural waxes that have been used as a support ingredient in cosmetic and pharmaceutical formulations. Although it has well-known healing properties, it remains a secondary and poorly valued product, particularly in South American countries' apiarian production. In Latin America, for example, the apiarian activity can be traced back to stingless bees in pre-Columbian times. Then, with the arrival of the Spaniards in the 16th century, honey bees (Apis mellifera iberian and A. m. mellifera) were introduced, which were joined afterward by other breeds such as A. m. ligustica and A. m. scutellata. Over the years, honey has been the main product from the apiarian farmers, being beeswax a secondary product, mainly used for the regular renewal procedure of the hives. Nowadays, beeswax's cosmetic and pharmaceutical use is found at the level of small laboratories and small businesses.
  • 7.5K
  • 10 Oct 2022
Topic Review
Seismometer
A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions, and explosions. Seismometers are usually combined with a timing device and a recording device to form a seismograph. The output of such a device—formerly recorded on paper (see picture) or film, now recorded and processed digitally—is a seismogram. Such data is used to locate and characterize earthquakes, and to study the Earth's internal structure.
  • 7.5K
  • 01 Dec 2022
Topic Review
Homology
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching primordia in successive segments of the same animal, are serially homologous. Examples include the legs of a centipede, the maxillary palp and labial palp of an insect, and the spinous processes of successive vertebrae in a vertebral column. Male and female reproductive organs are homologous if they develop from the same embryonic tissue, as do the ovaries and testicles of mammals including humans. Sequence homology between protein or DNA sequences is similarly defined in terms of shared ancestry. Two segments of DNA can have shared ancestry because of either a speciation event (orthologs) or a duplication event (paralogs). Homology among proteins or DNA is inferred from their sequence similarity. Significant similarity is strong evidence that two sequences are related by divergent evolution from a common ancestor. Alignments of multiple sequences are used to discover the homologous regions. Homology remains controversial in animal behaviour, but there is suggestive evidence that, for example, dominance hierarchies are homologous across the primates.
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  • 10 Oct 2022
Topic Review
Ideas of Reference and Delusions of Reference
Ideas of reference and delusions of reference describe the phenomenon of an individual experiencing innocuous events or mere coincidences and believing they have strong personal significance. It is "the notion that everything one perceives in the world relates to one's own destiny", usually in a negative and hostile manner. In psychiatry, delusions of reference form part of the diagnostic criteria for psychotic illnesses such as schizophrenia, delusional disorder, bipolar disorder (during the elevated stages of mania), as well as schizotypal personality disorder. To a lesser extent, it can be a hallmark of paranoid personality disorder, as well as body dysmorphic disorder. Such symptoms can also be caused by intoxication, such as stimulants like methamphetamine.
  • 7.5K
  • 20 Oct 2022
Topic Review
Biblical Cosmology
Biblical cosmology is the biblical writers' conception of the cosmos as an organised, structured entity, including its origin, order, meaning and destiny. The Bible was formed over many centuries, involving many authors, and reflects shifting patterns of religious belief; consequently, its cosmology is not always consistent. Nor do the biblical texts necessarily represent the beliefs of all Jews or Christians at the time they were put into writing: the majority of those making up Hebrew Bible or Old Testament in particular represent the beliefs of only a small segment of the ancient Israelite community, the members of a late Judean religious tradition centered in Jerusalem and devoted to the exclusive worship of Yahweh. The ancient Israelites envisaged a universe made up of a flat disc-shaped Earth floating on water, heaven above, underworld below. Humans inhabited Earth during life and the underworld after death; there was no way that mortals could enter heaven, and the underworld was morally neutral; only in Hellenistic times (after c. 330 BCE) did Jews begin to adopt the Greek idea that it would be a place of punishment for misdeeds, and that the righteous would enjoy an afterlife in heaven. In this period too the older three-level cosmology in large measure gave way to the Greek concept of a spherical earth suspended in space at the center of a number of concentric heavens. The opening words of the Genesis creation narrative (Genesis 1:1–26) sum up the biblical editors' view of how the cosmos originated: "In the beginning God created the heavens and the earth"; Yahweh, the God of Israel, was solely responsible for creation and had no rivals, implying Israel's superiority over all other nations. Later Jewish thinkers, adopting ideas from Greek philosophy, concluded that God's Wisdom, Word and Spirit penetrated all things and gave them unity. Christianity in turn adopted these ideas and identified Jesus with the Logos (Word): "In the beginning was the Word, and the Word was with God, and the Word was God" (John 1).
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  • 11 Jan 2024
Topic Review
Processing of Cereals and Derived-By-Products
Cereals have been one of the major food resources for human diets and animal feed for thousands of years, and a large quantity of by-products is generated throughout the entire processing food chain, from farm to fork. These by-products mostly consist of the germ and outer layers (bran) derived from dry and wet milling of the grains, of the brewers’ spent grain generated in the brewing industry, or comprise other types obtained from the breadmaking and starch production industries. Cereal processing by-products are an excellent low-cost source of various compounds such as dietary fibres, proteins, carbohydrates and sugars, minerals and antioxidants (such as polyphenols and vitamins), among others. Often, they are downgraded and end up as waste or, in the best case, are used as animal feed or fertilizers. With the increase in world population coupled with the growing awareness about environmental sustainability and healthy life-styles and well-being, the interest of the industry and the global market to provide novel, sustainable and innovative solutions for the management of cereal-based by-products is also growing rapidly.
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  • 15 Sep 2020
Topic Review
(ε, δ)-Definition of Limit
In calculus, the (ε, δ)-definition of limit ("epsilon–delta definition of limit") is a formalization of the notion of limit. The concept is due to Augustin-Louis Cauchy, who never gave a formal (ε, δ) definition of limit in his Cours d'Analyse, but occasionally used ε, δ arguments in proofs. It was first given as a formal definition by Bernard Bolzano in 1817, and the definitive modern statement was ultimately provided by Karl Weierstrass. It provides rigor to the following informal notion: the dependent expression f(x) approaches the value L as the variable x approaches the value c if f(x) can be made as close as desired to L by taking x sufficiently close to c.
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  • 22 Nov 2022
Topic Review
Ahiṃsā
Ahimsa (also spelt Ahinsa) (Sanskrit: अहिंसा IAST: ahiṃsā, Pāli: avihiṃsā) ("nonviolence," although see Etymology below) is an ancient Indian principle of nonviolence which applies to all living beings. It is a key virtue in Hinduism, Buddhism and Jainism. Ahimsa is one of the cardinal virtues of Jainism, where it is first of the Pancha Mahavrata. It is also the first of the five precepts of Buddhism. Ahimsa is a multidimensional concept, inspired by the premise that all living beings have the spark of the divine spiritual energy; therefore, to hurt another being is to hurt oneself. Ahimsa has also been related to the notion that any violence has karmic consequences. While ancient scholars of Hinduism pioneered and refined the principles of Ahimsa, the concept also reached an extraordinary development in the ethical philosophy of Jainism. lord Parsvanatha, the twenty-third tirthankara of Jainism, revived and preached the concept of non-violence in the 8th century BCE. Mahaviraswami, the twenty-fourth and the last tirthankara further strengthened the idea in the 6th century BCE. Perhaps the most popular advocate of the principle of Ahimsa was Mahatma Gandhi. Ahimsa's precept of 'cause no injury' includes one's deeds, words, and thoughts. Classical Hindu texts like the Mahabharata and Ramayana, as well as modern scholars, debate principles of Ahimsa when one is faced with war and situations requiring self-defence. Historical Indian literature has in this way contributed to modern theories of Just War and self-defence.
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  • 27 Oct 2022
Topic Review
Food Waste Management in Bangladesh
Food waste management is a critical environmental issue in many developing countries, including Bangladesh, due to unplanned food waste disposal and lack of dedicated food waste legislation. In those countries, a significant amount of food waste is discarded to the environment rather than being recycled. In Bangladesh, food waste is traditionally often used for composting, landfilling, and feeding animals, as there is no valorization option. In addition, food waste and food waste streams of food industries are utilized for the recycling and production of diverse economically valuable bioactive compounds.
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  • 18 Oct 2022
Topic Review
2D-MoS2
Two-dimensional (2D) materials are generally defined as crystalline substances with a few atoms thickness.Two-dimensional transition metal dichalcogenide (2D-TMDs) semiconducting (SC) materials have exhibited unique optical and electrical properties. The layered configuration of the 2D-TMDs materials is at the origin of their strong interaction with light and the relatively high mobility of their charge carriers, which in turn prompted their use in many optoelectronic applications, such as ultra-thin field-effect transistors, photo-detectors, light emitting diode, and solar-cells. Generally, 2D-TMDs form a family of graphite-like layered thin semiconducting structures with the chemical formula of MX2, where M refers to a transition metal atom (Mo, W, etc.) and X is a chalcogen atom (Se, S, etc.). The layered nature of this class of 2D materials induces a strong anisotropy in their electrical, chemical, mechanical, and thermal properties. In particular, molybdenum disulfide (MoS2) is the most studied layered 2D-TMD.
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  • 28 Sep 2021
Topic Review
Pathophysiology of Sepsis
Sepsis is a life-threatening condition characterized by an uncontrolled inflammatory response to an infectious agent and its antigens. Immune cell activation against the antigens causes severe distress that mediates a strong inflammatory response in vital organs. Sepsis is responsible for a high rate of morbidity and mortality in immunosuppressed patients. 
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  • 13 Mar 2023
Topic Review
Polyethylene Glycol
Lately, polyethylene glycol with nanoparticles has been demarcated as an innovative class of phase change materials with conceivable uses in the area of convective heat transfer. The amplified thermal conductivity of these nanoparticle enhanced phase change materials (PCMs) over the basic fluids (e.g., polyethylene glycol—PEG) is considered one of the driving factors for their improved performance in heat transfer.
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  • 08 Jan 2021
Topic Review
Mesoamerican Genetic Studies
Mesoamerica is a historically and culturally defined geographic area comprising current central and south Mexico, Belize, Guatemala, El Salvador, and border regions of Honduras, western Nicaragua, and northwestern Costa Rica. The permanent settling of Mesoamerica was accompanied by the development of agriculture and pottery manufacturing (2500 BCE–150 CE), which led to the rise of several cultures connected by commerce and farming. Hence, Mesoamericans probably carried an invaluable genetic diversity partly lost during the Spanish conquest and the subsequent colonial period. Mesoamerican ancient DNA (aDNA) research has mainly focused on the study of mitochondrial DNA in the Basin of Mexico and the Yucatán Peninsula and its nearby territories, particularly during the Postclassic period (900–1519 CE). 
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  • 24 Nov 2020
Topic Review
Urban Sociology
Urban sociology is the sociological study of life and human interaction in metropolitan areas. It is a normative discipline of sociology seeking to study the structures, environmental processes, changes and problems of an urban area and by doing so provide inputs for urban planning and policy making. In other words, it is the sociological study of cities and their role in the development of society. Like most areas of sociology, urban sociologists use statistical analysis, observation, social theory, interviews, and other methods to study a range of topics, including migration and demographic trends, economics, poverty, race relations and economic trends. Urban sociology is one of the oldest sub-disciplines of sociology dating back to the mid-nineteenth century. The philosophical foundations of modern urban sociology originate from the work of sociologists such as Karl Marx, Ferdinand Tönnies, Émile Durkheim, Max Weber and Georg Simmel who studied and theorized the economic, social and cultural processes of urbanization and its effects on social alienation, class formation, and the production or destruction of collective and individual identities. These theoretical foundations were further expanded upon and analyzed by a group of sociologists and researchers who worked at the University of Chicago in the early twentieth century. In what became known as the Chicago School of sociology the work of Robert Park, Louis Wirth and Ernest Burgess on the inner city of Chicago revolutionized not only the purpose of urban research in sociology, but also the development of human geography through its use of quantitative and ethnographic research methods. The importance of the theories developed by the Chicago School within urban sociology have been critically sustained and critiqued but still remain one of the most significant historical advancements in understanding urbanization and the city within the social sciences. The discipline may draw from several fields, including cultural sociology, economic sociology, and political sociology.
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  • 01 Nov 2022
Topic Review
Proofs Involving the Moore–Penrose Inverse
In linear algebra, the Moore–Penrose inverse is a matrix that satisfies some but not necessarily all of the properties of an inverse matrix. This article collects together a variety of proofs involving the Moore–Penrose inverse.
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  • 01 Dec 2022
Topic Review
Embryology of Aorta
The aorta is the largest elastic artery in the human body and is classically divided into two anatomical segments, the thoracic and the abdominal aorta, separated by the diaphragm. The thoracic aorta includes the aortic root, the ascending aorta, the arch, and the descending aorta. The aorta’s elastic properties depend on its wall structure, composed of three distinct histologic layers: intima, media, and adventitia. The different aortic segments show different embryological and anatomical features, which account for their different physiological properties and impact the occurrence and natural history of congenital and acquired diseases that develop herein.
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  • 30 Jun 2023
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