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Topic Review

Teeth Blackening

Teeth blackening or teeth lacquering is a custom of dyeing one's teeth black. It was most predominantly practiced in Southeast Asian and Oceanic cultures, particularly among Austronesian, Austroasiatic, and Kra-Dai-speaking peoples. It was also practiced in Japan prior to the Meiji era, as well as in India. It was also performed among some groups in the Americas, most notably among the Shuar people of northern Peru and Ecuador. Teeth blackening is usually done during puberty. It was primarily done to preserve the teeth into old age, as it prevents tooth decay similar to the mechanism of modern dental sealants. It was seen as a sign of maturity, beauty, and civilization. A common belief is that blackened teeth differentiated humans from animals. Teeth blackening is often done in conjunction with traditions of tooth sharpening and evulsion, as well as other body modification customs like tattoos. Teeth blackening and filing were regarded with fascination and disapproval by early European explorers and colonists. The practice survives in some isolated ethnic groups in Southeast Asia and Oceania but has mostly disappeared after the introduction of Western beauty standards during the colonial era, and continues among many minority groups in China, Pacific Islands and Southeast Asia. It is mainly prevalent in older women, though the practice is still carried on by some younger women. Sometimes artificial teeth are used to achieve blackened teeth. Teeth blackening is commonly confused with the red-stained teeth from betel chewing. However, betel chewing damages the teeth and gums, while teeth blackening does not.

8.8K
21 Nov 2022

Topic Review

Prohibited Degree of Kinship

In law, a prohibited degree of kinship refers to a degree of consanguinity (blood relatedness) and sometimes affinity (relation by marriage or sexual relationship) between persons that results in certain actions between them being illegal. Two major examples of prohibited degrees are found in incest and nepotism. Incest refers to sexual relations and marriage between closely related individuals; nepotism is the preference of blood-relations in the distribution of a rank or office. An incest taboo against sexual relations between parent and child or two full-blooded siblings is a cultural universal. Taboos against sexual relations between individuals of other close degrees of relationship vary, but stigmatization of unions with full siblings and with direct descendants are widespread.

8.8K
19 Oct 2022

Topic Review

Devil in Christianity

The Devil in Christianity is the personification of evil and author of sin, who rebelled against God in an attempt to become equal to God himself.[lower-alpha 1] He is depicted as a fallen angel, who was expelled from Heaven at the beginning of time, before God created the material world, and is in constant opposition to God. The devil is identified with several figures in the Bible including the serpent in the Garden of Eden, Lucifer, Satan, the tempter of the Gospels, Leviathan, and the dragon in the Book of Revelation. Early scholars discussed the role of the devil. Scholars influenced by neoplatonic cosmology, like Origen and Pseudo-Dionysius, portrayed the devil as representing deficiency and emptiness, the entity most remote from the divine. According to Augustine of Hippo the realm of the devil is not nothingness, but an inferior realm standing in opposition to God. The standard Medieval depiction of the devil was set up by Gregory the Great. He integrated the devil, as the first creation of God, into the Christian angelic hierarchy as the highest of the angels (either a cherub or a seraph). But as high as he stood in heaven, so far he fell into the depths of hell and became the leader of demons. Since the early reformation period, the devil was imagined as an increasingly powerful entity, with not only a lack of goodness but also a conscious will against God, his word, and his creation. Simultaneously, some reformists interpreted the devil as a mere metaphor for human's inclination to sin and so downgraded the importance of the devil. While the devil played for most scholars no significant role in the Modern Era, he became more important in contemporary Christianity again. At various times in history, some people such as the Cathars and the Bogomiles, as well as theologians like Marcion and Valentinus, believed that the devil was involved in creating the world. Today these views are not part of mainstream Christianity.

8.8K
06 Dec 2022

Topic Review

Rice hulls (or rice husks) are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, or fuel. Rice hulls are part of the chaff of the rice.

8.8K
10 Oct 2022

Topic Review

Stall (Fluid Mechanics)

In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded. The critical angle of attack is typically about 15 degrees, but it may vary significantly depending on the fluid, foil, and Reynolds number. Stalls in fixed-wing flight are often experienced as a sudden reduction in lift as the pilot increases the wing's angle of attack and exceeds its critical angle of attack (which may be due to slowing down below stall speed in level flight). A stall does not mean that the engine(s) have stopped working, or that the aircraft has stopped moving—the effect is the same even in an unpowered glider aircraft. Vectored thrust in manned and unmanned aircraft is used to surpass the stall limit, thereby giving rise to post-stall technology. Because stalls are most commonly discussed in connection with aviation, this article discusses stalls as they relate mainly to aircraft, in particular fixed-wing aircraft. The principles of stall discussed here translate to foils in other fluids as well.

8.8K
16 Nov 2022

Topic Review

Viroids: Definition and Features

Viroids are plant-restricted parasites that represent a remarkable model system to analyze many aspects of host-pathogen interactions at the genomic level. As the smallest known agents of infectious disease (247-401 nucleotides, nt), they have a highly structured, single-stranded circular naked and non-coding RNA genome. Although the list of known diseases caused by viroids and molecular characterization of the causative agents has expanded since they were discovered, their origin, evolution, and interaction with host genetic machinery to induce symptoms or escape the defensive system remain unclear.

8.8K
01 Nov 2020

Topic Review

Industry 4.0 and Sustainability

Sustainability and Industry 4.0 (I4.0) are trending concepts used in the literature on industrial processes. Industry 4.0 has been mainly addressed by the current literature from a technological perspective, overlooking sustainability challenges regarding this recent paradigm. The objective of this encyclopedia entry is to evaluate the state of the art of relations between sustainability and I4.0. The goal will be met by (1) mapping and summarizing existing research efforts, (2) identifying research agendas, (3) examining gaps and opportunities for further research. Web of Science, Scopus, and a set of specific keywords were used to select peer-reviewed papers presenting evidence on the relationship between sustainability and I4.0. To achieve this goal, it was decided to use a dynamic methodology called “systematic literature network analysis”. This methodology combines a systematic literature review approach with the analysis of bibliographic networks. Selected papers were used to build a reference framework formed by I4.0 technologies and sustainability issues. The encyclopedia entry contributes to the Sustainable Industry 4.0 reference framework with application procedures. It aims to show how I4.0 can support ideas of sustainability. The results showed that apart from a huge contribution to both concepts, many papers do not provide an insight into realization of initiatives to introduce Sustainable Industry 4.0.

8.8K
06 Jun 2021

Topic Review

Permeability (Earth Sciences)

Permeability in fluid mechanics and the earth sciences (commonly symbolized as κ, or k) is a measure of the ability of a porous material (often, a rock or an unconsolidated material) to allow fluids to pass through it. The permeability of a medium is related to the porosity, but also to the shapes of the pores in the medium and their level of connectedness.

8.8K
25 Oct 2022

Topic Review

In God We Trust

"In God We Trust" (also rendered as "In God we trust") is the official motto of the United States and of the U.S. state of Florida. It was adopted by the U.S. Congress in 1956, replacing E pluribus unum ("Out of many, one"), which had been the de facto motto since the initial design of the Great Seal of the United States. While the earliest mentions of the phrase can be found in the mid-19th century, the origins of this phrase as a political motto lie in the American Civil War, where Union supporters wanted to emphasize their attachment to God and to boost morale. The capitalized form "IN GOD WE TRUST" first appeared on the two-cent piece in 1864; it was not printed on paper currency until 1957 and on some postage stamps until 1954. A law passed in July 1955 by a joint resolution of the 84th Congress (Pub.L. 84–140) and approved by President Dwight Eisenhower requires that "In God We Trust" appear on all United States dollar . Two years later, the phrase was used on paper money for the first time — on the updated one-dollar silver certificate that entered circulation on October 1, 1957. The 84th Congress later passed legislation (Pub.L. 84–851), also signed by President Eisenhower on July 30, 1956, declaring the phrase to be the national motto. Several states have also mandated or authorized its use in public institutions or schools; while Florida, Georgia and Mississippi have incorporated the phrase in some of their state symbols. The motto has also been used in some cases in other countries, most notably on Nicaragua's coins.The motto remains popular among the American public. According to a 2003 joint poll by USA Today, CNN, and Gallup, 90% of Americans support the inscription "In God We Trust" on U.S. coins; and a 2019 student poll by College Pulse showed that 53% of students supported its inclusion in currency. Some groups and people in the United States, however, have objected to its use, contending that its religious reference violates the Establishment Clause of the First Amendment. These groups believe the phrase should be removed from currency and public property, which has resulted in numerous lawsuits. This argument has not overcome the interpretational doctrine of accommodationism, which allows the government to endorse religious establishments as long as they are all treated equally, and that of "ceremonial deism", which states that a repetitious invocation of a religious entity in ceremonial matters strips the phrase of its original religious connotation. The New Hampshire Supreme Court, as well as Second, Fourth, Sixth, Eighth, Ninth, and Tenth Circuits have all upheld the constitutionality of the motto in various settings. The Supreme Court has discussed the motto in footnotes but has never directly ruled on its compliance with the Constitution.

8.8K
30 Nov 2022

Biography

Jalāl al-Dīn Muḥammad Rūmī

Jalāl al-Dīn Muḥammad Rūmī (Persian: جلال‌الدین محمد رومی‎), also known as Jalāl al-Dīn Muḥammad Balkhī (جلال‌الدین محمد بلخى), Mevlânâ/Mawlānā (Persian: مولانا‎, lit. 'our master') and Mevlevî/Mawlawī (Persian: مولوی‎, lit. 'my master'), but more popularly known simply as Rumi (30 September 1207 – 17 December 1273), wa

8.8K
05 Dec 2022

Topic Review

Aerial Microbial Contamination

Air is recognized as an important source of microbial contamination in food production facilities and has the potential to contaminate the food product causing food safety and spoilage issues for the food industry. Potential for aerial microbial contamination of food can be a particular issue during storage in cold rooms when the food is not packaged and is exposed to contaminated air over a prolonged period. Thus, there are potential benefits for the food industry for an aerial decontamination in cold storage facilities. It is considered that current systems may not be completely effective and environmentally friendly, therefore, it is of great significance to consider the development of nonresidual and verified decontamination technologies for the food industry and, in particular, for the cold storage rooms.

8.8K
17 Dec 2020

Topic Review

Pigmentary and Structural Coloration in Nature

Most of us get inspired by and interact with the world around us based on visual cues such as the colors and patterns that we see. In nature, coloration takes three primary forms: pigmentary coloration, structural coloration, and bioluminescence. Typically, pigmentary and structural coloration are used by animals and plants for their survival. These forms of coloration are enabled by a variety of intracellular biophotonic structures.

8.8K
09 Jun 2022

Topic Review

“OVERTOURISM” - AROUND THE DEFINITION

Entry includes definition of overtourism phenomenon around the world with following literature references both historical and current research.

8.7K
19 Apr 2021

Topic Review

Partition Problem

In number theory and computer science, the partition problem, or number partitioning, is the task of deciding whether a given multiset S of positive integers can be partitioned into two subsets S1 and S2 such that the sum of the numbers in S1 equals the sum of the numbers in S2. Although the partition problem is NP-complete, there is a pseudo-polynomial time dynamic programming solution, and there are heuristics that solve the problem in many instances, either optimally or approximately. For this reason, it has been called "the easiest hard problem". There is an optimization version of the partition problem, which is to partition the multiset S into two subsets S1, S2 such that the difference between the sum of elements in S1 and the sum of elements in S2 is minimized. The optimization version is NP-hard, but can be solved efficiently in practice.

8.7K
10 Oct 2022

Topic Review

Eukaryotic Ribosome (80S)

Ribosomes are a large and complex molecular machine that catalyzes the synthesis of proteins, referred to as translation. The ribosome selects aminoacylated transfer RNAs (tRNAs) based on the sequence of a protein-encoding messenger RNA (mRNA) and covalently links the amino acids into a polypeptide chain. Ribosomes from all organisms share a highly conserved catalytic center. However, the ribosomes of eukaryotes (animals, plants, fungi, and many unicellular organisms with a nucleus) are much larger than prokaryotic (bacterial and archaeal) ribosomes and subject to more complex regulation and biogenesis pathways. Eukaryotic ribosomes are also known as 80S ribosomes, referring to their sedimentation coefficients in Svedberg units, because they sediment faster than the prokaryotic (70S) ribosomes. Eukaryotic ribosomes have two unequal subunits, designated small subunit (40S) and large subunit (60S) according to their sedimentation coefficients. Both subunits contain dozens of ribosomal proteins arranged on a scaffold composed of ribosomal RNA (rRNA). The small subunit monitors the complementarity between tRNA anticodon and mRNA, while the large subunit catalyzes peptide bond formation.

8.7K
14 Apr 2023

Topic Review

Peer pressure is the direct or indirect influence on people of peers, members of social groups with similar interests, experiences, or social statuses. Members of a peer group are more likely to influence a person's beliefs and behavior. A group or individual may be encouraged and want to follow their peers by changing their attitudes, values or behaviors to conform to those of the influencing group or individual. For the individual affected by peer pressure, this can result in either a positive or negative effect or both. Social groups include both membership groups in which individuals hold "formal" membership (e.g. political parties, trade unions, schools) and cliques in which membership is less clearly defined. However, a person does not need to be a member or be seeking membership of a group to be affected by peer pressure. Research suggests that organizations as well as individuals are susceptible to peer pressure. For example, a large company may be influenced by other firms in their industry or from headquarters. Peer pressure can affect individuals of all ethnicities, genders and ages. Researchers have frequently studied the effects of peer pressure on children and on adolescents, and in popular discourse the term "peer pressure" is used most often with reference to those age-groups. For children, the themes most commonly studied are their abilities for independent decision-making. For adolescents, peer pressure's relationships to sexual intercourse and substance abuse have been significantly researched. Peer pressure can be experienced through both face-to-face interaction and through digital interaction. Social media offers opportunities for adolescents and adults alike to instill and/or experience pressure every day. Studies of social networks examine connections between members of social groups, including their use of social media, to better understand mechanisms such as information sharing and peer sanctioning. Sanctions can range from subtle glances that suggest disapproval, to threats and physical violence. Peer sanctioning may enhance either positive or negative behaviors. Whether peer sanctioning will have an effect depends in part on members' expectations that possible sanctions will actually be applied. It can also depend on a person's position in a social network. Those who are more central in a social network seem more likely to be cooperative, perhaps as a result of how networks form. However, this goes both ways and so they are also more likely to participate in negative behaviors. This may be caused by the repeated social pressures they experience in their networks.

8.7K
07 Nov 2022

Topic Review

Sub Synchronous Oscillation Phenomenon

The definition of sub synchronous oscillation (SSO) according to the IEEE Sub Synchronous Resonance Working Group is as follows. “Sub synchronous oscillation is an electric power system condition where the electric network exchanges significant energy with a turbine generator at one or more of the natural frequencies of the combined system below the synchronous frequency of the system following a disturbance from equilibrium”. According to the classification of SSO by the IEEE Sub Synchronous Resonance Working Group, there are two types of SSO, namely sub synchronous resonance (SSR) and device dependent sub synchronous oscillation (DDSSO). Sub synchronous control interaction (SSCI) and sub synchronous torsional interaction (SSTI) are other types of SSO. However, they are not included in the formal classification.

8.7K
09 Dec 2022

Topic Review

Ascorbic Acid-Mediated Reactions

Ascorbic acid is a vitamin found in different types of food. It has tremendous medical applications in several different fields such as in pharmaceuticals, cosmetics, and in organic synthesis.

8.7K
25 Nov 2020

Topic Review

Agorism is a libertarian social philosophy that advocates creating a society in which all relations between people are voluntary exchanges by means of counter-economics, thus engaging with aspects of peaceful revolution. It was first proposed by libertarian philosopher Samuel Edward Konkin III at two conferences, CounterCon I in October 1974 and CounterCon II in May 1975, both conferences organized by J. Neil Schulman.

8.7K
23 Nov 2022

Topic Review

Cannabis sativa L.

Hemp (Cannabis sativa L.) is an ancient, widespread, multipurpose crop cultivated all over the world, all parts of which can be potentially usable for the production of many different commodities with industrial interest. It is one of the oldest cultivated crops and until the first half of the 1900s, it was widely grown essentially as a fibre crop. Declining the demand for natural fibre consequential to the upper hand of synthetic fibre, and competition from other plant fibre sources led to reduce the demand for hemp. In addition, the use of some narcotic strains containing high and unhealthy level (>0.3%) of the only one psychoactive substance, namely the cannabinoid delta-9 tetrahydrocannabinol (THC), led to the crop's prohibition during much of the 20th century. The clarification of the genetics and the biosynthetic pathway of the cannabinoids has been essential to identify three main different genotypes and the related chemical phenotypes of hemp plants, differing in the content of the two main hemp cannabinoids, THC and cannabidiol (CBD). Among these, the chemical phenotype commonly named "industrial hemp" includes hemp varieties which contain <0.3% or 0.2% of THC level that makes them unsuitable for narcotic purposes, but very useful for many other industrial applications. Therefore, from a legislative point of view, the main western countries such as United States, Canada, and European Union after a prohibition period, from the last decade of 1900s, have reintroduced and restored the industrial hemp cultivation.

8.7K
10 Jul 2020

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