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Topic Review
Prokaryotic Translation
Prokaryotic translation is the process by which messenger RNA is translated into proteins in prokaryotes.
  • 5.0K
  • 19 Oct 2022
Topic Review
Mammy Archetype
A mammy, also spelled mammie, is a U.S. stereotype, especially in the South, for a black woman who worked in a white family and nursed the family's children.
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  • 29 Nov 2022
Topic Review
Descendants of the Bounty Mutineers
The descendants of the Bounty mutineers and their Tahitian consorts include the modern-day Pitcairn Islanders as well as a little less than half of the population of Norfolk Island. Their descendants also live in New Zealand, Australia, and the United States. Because of the scarcity of people on the island, many of the mutineers' children and grandchildren intermarried, with some marrying cousins and second cousins. Occasionally a new person would arrive on the island bringing with them a new surname (like the American Samuel Russell Warren, whose descendants still live on the island today).
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  • 25 Oct 2022
Topic Review
Chemical looping
Chemical looping technology in general, is the rising star in chemical technologies, which is capable of low CO2 emissions with applications in the production of heat, fuels, chemicals, and electricity. This entry discusses the technology in general, gives an overview of some pilot scale plants and the different chemical looping processes with focus on the production of heat and chemicals, highlights the importance of the development of oxygen carrier materials with suitable properties, 2.11.0.0 2.11.0.0
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  • 02 Nov 2020
Topic Review
Frame of Reference
In physics, a frame of reference (or reference frame) consists of an abstract coordinate system and the set of physical reference points that uniquely fix (locate and orient) the coordinate system and standardize measurements within that frame. For n dimensions, n + 1 reference points are sufficient to fully define a reference frame. Using rectangular (Cartesian) coordinates, a reference frame may be defined with a reference point at the origin and a reference point at one unit distance along each of the n coordinate axes. In Einsteinian relativity, reference frames are used to specify the relationship between a moving observer and the phenomenon or phenomena under observation. In this context, the phrase often becomes "observational frame of reference" (or "observational reference frame"), which implies that the observer is at rest in the frame, although not necessarily located at its origin. A relativistic reference frame includes (or implies) the coordinate time, which does not correspond across different frames moving relatively to each other. The situation thus differs from Galilean relativity, where all possible coordinate times are essentially equivalent.
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  • 21 Oct 2022
Topic Review
Effects of Creatine Supplementation on Brain Function
Creatine, a nitrogenous organic compound derived from reactions involving the amino acids arginine, glycine, and methionine, is important for resynthesizing ATP, particularly during times of increased metabolic demand (e.g., sleep deprivation, mental health conditions, or neurological diseases). Creatine supplementation (and guanidinoacetic acid; GAA) has the ability to increase brain creatine content in humans. Furthermore, creatine has shown some promise for attenuating symptoms of concussion, mild traumatic brain injury and depression but its effect on neurodegenerative diseases appears to be lacking. 
  • 5.0K
  • 09 Jun 2022
Topic Review
Naturopathy
Naturopathy, or naturopathic medicine, is a form of alternative medicine. It employs an array of pseudoscientific practices branded as "natural", "non-invasive", or promoting "self-healing". The practices of naturopaths, the practitioners of naturopathic medicine, vary widely and are difficult to generalize. Treatments range from outright quackery, like homeopathy, to widely accepted practices like psychotherapy. The ideology and methods of naturopathy are based on vitalism and folk medicine rather than evidence-based medicine (EBM), although some practitioners may use techniques supported by EBM. Naturopathic practitioners commonly recommend against following modern medical practices, including but not limited to medical testing, drugs, vaccinations, and surgery. Instead, naturopathic practice relies on unscientific notions, often leading naturopaths to diagnoses and treatments that have no factual merit. Naturopathy is considered by the medical profession to be ineffective and harmful, raising ethical issues about its practice. In addition to condemnations and criticism from the medical community, such as the American Cancer Society, naturopaths have repeatedly been denounced as and accused of being charlatans and practicing quackery. Naturopaths are known for their frequent campaigning for legal recognition in the United States . It is illegal in two U.S. states and tightly regulated in many others. Some states have lax regulations, however, and may allow naturopaths to perform minor surgery or even prescribe drugs. While some schools exist for naturopaths, and some jurisdictions allow such practitioners to call themselves doctors, the lack of accreditation and scientific medical training means they lack the competency of true medical doctors.
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  • 24 Oct 2022
Topic Review
Ural–Altaic Languages
Ural–Altaic, Uralo-Altaic or Uraltaic is a linguistic convergence zone and former language-family proposal uniting the Uralic and the Altaic (in the narrow sense) languages. It is generally now agreed that even the Altaic languages most likely do not share a common descent: the similarities among Turkic, Mongolic and Tungusic are better explained by diffusion and borrowing. The term continues to be used for the central Eurasian typological, grammatical and lexical convergence zone. Indeed, "Ural-Altaic" may be preferable to "Altaic" in this sense. For example, J. Janhunen states that "speaking of 'Altaic' instead of 'Ural-Altaic' is a misconception, for there are no areal or typological features that are specific to 'Altaic' without Uralic." Originally suggested in the 18th century, the genealogical and racial hypotheses remained debated into the mid-20th century, often with disagreements exacerbated by pan-nationalist agendas. It had many proponents in Britain. Since the 1960s, the proposed language family has been widely rejected. A relationship between the Altaic, Indo-European and Uralic families was revived in the context of the Nostratic hypothesis, which was popular for a time, with for example Allan Bomhard treating Uralic, Altaic and Indo-European as coordinate branches. However, Nostratic too is now mostly rejected.
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  • 31 Oct 2022
Topic Review
NTC-Properties of a Geomorphic Clinoptilolite Sample
Negative temperature coefficient (NTC) materials are usually based on ceramic semiconductors, and electrons are involved in their transport mechanism. A new type of NTC material, adequate for alternating current (AC) applications, is represented by zeolites. Indeed, zeolites are single charge carrier ionic conductors with a temperature-dependent electrical conductivity. In particular, electrical transport in zeolites is due to the monovalent charge-balancing cations, like K+, capable of hopping between negatively charged sites in the aluminosilicate framework. Owing to the highly non-linear electrical behavior of the traditional electronic NTC materials, the possibility to have alternative types of materials, showing linearity in their electrical behavior, is very desirable. Among different zeolites, natural clinoptilolite has been selected for investigating NTC behavior since it is characterized by high zeolite content, a convenient Si/Al atomic ratio, good mechanical strength due to its compact microstructure, and low toxicity. Clinoptilolite has shown a rapid and quite reversible impedance change under heating, characterized by a linear dependence on temperature.
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  • 11 Jul 2024
Topic Review
Outsourcing in Supply Chain Management
Outsourcing is one of the major challenges for production firms in the current supply chain management (SCM) due to limited skilled workers and technology resources. There are too many parameters involved in the strategic decisions of the outsourcing level, quantity, quality, and cost. 
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  • 27 Apr 2022
Topic Review
Dairy Spoilage and Pseudomonas spp.
The refrigerated fresh foods tend to quickly deteriorate along its production and marketing, mainly due to the action of psychrotrophic spoilage microorganisms such as pseudomonads. These bacteria cause discolouration, texture loss and unpleasant flavours, with fatal implications for the quality and shelf life of products. Refirgerated fresh dairy products as well as fresh foods are steadly threatened by these microorganisms against which most control strategies are uneffective.
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  • 19 Apr 2022
Topic Review
Targeted Therapy for NSCLC Patients with EGFR Mutations
Oncogenic mutations within the epidermal growth factor receptor (EGFR) kinase domain are well-established driver mutations in non–small cell lung cancer (NSCLC). Small-molecule tyrosine kinase inhibitors (TKIs) specifically targeting these mutations have improved treatment outcomes for patients with this subtype of NSCLC. Multiple targeted agents, including first-, second- and third-generation EGFR TKIs, have been approved or are under active investigation for patients with EGFR-mutant NSCLC. The first-generation TKIs, including erlotinib and gefitinib, are reversible inhibitors, binding both to mutant as well as wild-type (WT) EGFR. The second-generation TKIs, including afatinib and dacomitinib, are irreversible inhibitors that covalently bind to EGFR. The third-generation EGFR TKIs, including osimertinib (AZD9291), aumolertinib (HS-10296) and alflutinib (AST2818), are irreversible inhibitors that selectively bind to mutant EGFR and show greater efficacy than the first- and second-generation TKIs. Osimertinib has been approved by the FDA for both frontline and second-line treatment of NSCLC with EGFR-sensitizing mutations. Aumolertinib (HS-10296) and alflutinib (AST2818) have been approved for the treatment of EGFR-mutant NSCLC in China. Acquired resistance inevitably occurs, and a promising new generation of EGFR-targeting agents is under investigation.
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  • 09 Feb 2023
Topic Review
Identity
Identity refers to the distinct and unique set of characteristics, qualities, beliefs, and affiliations that define an individual or a group. It encompasses various aspects, including personal attributes, cultural heritage, social roles, and a sense of belonging. Identity is dynamic, shaped by personal experiences, societal influences, and the interactions between individuals and their broader cultural, social, and historical contexts. It plays a crucial role in shaping how individuals perceive themselves and how they are perceived by others. Additionally, identity can be expressed through factors such as ethnicity, nationality, gender, religion, and personal values, contributing to the richness and diversity of human experiences.
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  • 25 Jan 2024
Topic Review
Multi-Robot Systems
When applications require the integration and collaborative efforts of several robots, the collective of robots is referred to as a Multi-Robot System (MRS).
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  • 17 Dec 2021
Topic Review
Hole-Transporting Layer in Perovskite Solar Cells
Organic-inorganic halide perovskite solar cells (PSCs) have received particular attention because of the high-power conversion efficiencies (PCEs), facile fabrication route and low cost. The hole-transporting layer (HTL) play an important role in PSCs to effectively extract holes from the perovskite film and to transport holes to the metal electrode in normal PSCs. 
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  • 09 Aug 2022
Topic Review
Electric Vehicles Charging/Discharging and Battery Degradation
The high penetration of electric vehicles (EVs) will burden the existing power delivery infrastructure if their charging and discharging are not adequately coordinated. The degradation of lithium-ion batteries occurs throughout their lives due to several chemicals and mechanical processes that reduce the cyclable lithium and other active materials. Battery degradation depends on many factors, such as the charging and discharging rates, depth of discharge (DOD), temperature, voltage, cycle number, and storage stage of charge.
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  • 17 Jan 2023
Topic Review
Evolutionary History of Life
The evolutionary history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to the present. Earth formed about 4.5 billion years (Ga) ago and evidence suggests life emerged prior to 3.7 Ga. (Although there is some evidence of life as early as 4.1 to 4.28 Ga, it remains controversial due to the possible non-biological formation of the purported fossils.) The similarities among all known present-day species indicate that they have diverged through the process of evolution from a common ancestor. Approximately 1 trillion species currently live on Earth of which only 1.75–1.8 million have been named and 1.6 million documented in a central database. These currently living species represent less than one percent of all species that have ever lived on earth. The earliest evidence of life comes from biogenic carbon signatures and stromatolite fossils discovered in 3.7 billion-year-old metasedimentary rocks from western Greenland. In 2015, possible "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia. In March 2017, putative evidence of possibly the oldest forms of life on Earth was reported in the form of fossilized microorganisms discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada, that may have lived as early as 4.28 billion years ago, not long after the oceans formed 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. Microbial mats of coexisting bacteria and archaea were the dominant form of life in the early Archean Epoch and many of the major steps in early evolution are thought to have taken place in this environment. The evolution of photosynthesis, around 3.5 Ga, eventually led to a buildup of its waste product, oxygen, in the atmosphere, leading to the great oxygenation event, beginning around 2.4 Ga. The earliest evidence of eukaryotes (complex cells with organelles) dates from 1.85 Ga, and while they may have been present earlier, their diversification accelerated when they started using oxygen in their metabolism. Later, around 1.7 Ga, multicellular organisms began to appear, with differentiated cells performing specialised functions. Sexual reproduction, which involves the fusion of male and female reproductive cells (gametes) to create a zygote in a process called fertilization is, in contrast to asexual reproduction, the primary method of reproduction for the vast majority of macroscopic organisms, including almost all eukaryotes (which includes animals and plants). However the origin and evolution of sexual reproduction remain a puzzle for biologists though it did evolve from a common ancestor that was a single celled eukaryotic species. Bilateria, animals having a left and a right side that are mirror images of each other, appeared by 555 Ma (million years ago). The earliest complex land plants date back to around 850 Ma, from carbon isotopes in Precambrian rocks, while algae-like multicellular land plants are dated back even to about 1 billion years ago, although evidence suggests that microorganisms formed the earliest terrestrial ecosystems, at least 2.7 Ga. Microorganisms are thought to have paved the way for the inception of land plants in the Ordovician. Land plants were so successful that they are thought to have contributed to the Late Devonian extinction event. (The long causal chain implied seems to involve the success of early tree archaeopteris (1) drew down CO2 levels, leading to global cooling and lowered sea levels, (2) roots of archeopteris fostered soil development which increased rock weathering, and the subsequent nutrient run-off may have triggered algal blooms resulting in anoxic events which caused marine-life die-offs. Marine species were the primary victims of the Late Devonian extinction.) Ediacara biota appear during the Ediacaran period, while vertebrates, along with most other modern phyla originated about 525 Ma during the Cambrian explosion. During the Permian period, synapsids, including the ancestors of mammals, dominated the land, but most of this group became extinct in the Permian–Triassic extinction event 252 Ma. During the recovery from this catastrophe, archosaurs became the most abundant land vertebrates; one archosaur group, the dinosaurs, dominated the Jurassic and Cretaceous periods. After the Cretaceous–Paleogene extinction event 66 Ma killed off the non-avian dinosaurs, mammals increased rapidly in size and diversity. Such mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.
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  • 24 Nov 2022
Topic Review
List of Dell PowerEdge Servers
Dell PowerEdge is a server line by Dell, following the naming convention for other Dell products: the PowerVault (data storage) and the PowerConnect (data transfer & switches). Below is an overview of current and former servers within Dell's PowerEdge product line. Different models are or were available as towers, 19-inch racks or blades. In the current naming scheme, towers are designated by T, racks by R, and blades by M (for modular). The 19″ rack-servers come in different physical heights expressed in rack units or U. Most modern servers are either 1U or 2U high while in the past the 4U was more common.
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  • 21 Oct 2022
Topic Review
Chi-Square Distribution
In probability theory and statistics, the chi-square distribution (also chi-squared or χ2-distribution) with k degrees of freedom is the distribution of a sum of the squares of k independent standard normal random variables. The chi-square distribution is a special case of the gamma distribution and is one of the most widely used probability distributions in inferential statistics, notably in hypothesis testing and in construction of confidence intervals. This distribution is sometimes called the central chi-square distribution, a special case of the more general noncentral chi-square distribution. The chi-square distribution is used in the common chi-square tests for goodness of fit of an observed distribution to a theoretical one, the independence of two criteria of classification of qualitative data, and in confidence interval estimation for a population standard deviation of a normal distribution from a sample standard deviation. Many other statistical tests also use this distribution, such as Friedman's analysis of variance by ranks.
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  • 11 Nov 2022
Topic Review
Group Work
Group work is a form of voluntary association of members benefiting from cooperative learning, that enhances the total output of the activity than when done individually. It aims to cater for individual differences, develop skills (e.g. communication skills, collaborative skills, critical thinking skills), generic knowledge and socially acceptable attitudes or to generate conforming standards of behavior and judgement, a "group mind". Specifically in psychotherapy and social work, "group work" refers to group therapy, offered by a practitioner trained in psychotherapy, psychoanalysis, counseling or other relevant discipline. The field of Social work includes all voluntary attempts to extend benefits in response to a bio-psycho-social needs and avails them through scientific knowledge and structured methods. There are six approaches in Social Work:
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  • 31 Oct 2022
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