Your browser does not fully support modern features. Please upgrade for a smoother experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Myeloid-Derived Suppressor Cells
Myeloid-derived suppressor cells (MDSCs) are heterogeneous cells derived from bone marrow. They are precursors of dendritic cells, macrophages and/or granulocytes. They have the ability to significantly inhibit immune cell responses.
  • 5.1K
  • 27 Oct 2020
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.
  • 5.1K
  • 24 Oct 2022
Topic Review
Effects of Global Warming
The effects of global warming or climate damage include far-reaching and long-lasting changes to the natural environment, to ecosystems and human societies caused directly or indirectly by human emissions of greenhouse gases. It also includes the economic and social changes which stem from living in a warmer world. Human caused climate change is one of the threats to sustainability. Many physical impacts of global warming are already visible, including extreme weather events, glacier retreat, changes in the timing of seasonal events (e.g., earlier flowering of plants), sea level rise, and declines in Arctic sea ice extent. The future impact of global warming depends on the extent to which nations implement prevention efforts and reduce greenhouse gas emissions. Ocean acidification is not a consequence of global warming, but instead has the same cause: increasing atmospheric carbon dioxide. Climate change has already impacted ecosystems and humans as well. In combination with climate variability, it makes food insecurity worse in many places and puts pressure on fresh water supply. This in combination with extreme weather events, leads to negative effects on human health. Rising temperatures threaten development because of negative effects on economic growth in developing countries. The social impact of climate change will be further affected by society's efforts to prepare and adapt. Global warming already contributes to migration in different parts of the world. Near-term climate change policies significantly affect long-term climate change impacts. Stringent mitigation policies might be able to limit global warming (in 2100) to around 2 °C or below, relative to pre-industrial levels. Without mitigation, increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 °C. Higher magnitudes of global warming would be more difficult to adapt to, and would increase the risk of negative impacts.
  • 5.1K
  • 01 Nov 2022
Topic Review
Blading (Professional Wrestling)
In professional wrestling, blading is the practice of intentionally cutting oneself to provoke bleeding. It is also known as "juicing", "gigging", or "getting color". Similarly, a blade is an object used for blading and a bladejob is a specific act of blading. The act is usually done a good length into the match as the blood will mix with the flowing sweat to make it look like much more blood is flowing from the wound than there actually is. The preferred area for blading is usually the forehead, as scalp wounds bleed profusely and heal easily. Legitimate, unplanned bleeding which occurs outside the storyline is called "juicing the hard way".
  • 5.1K
  • 24 Oct 2022
Topic Review
Closed Graph
In mathematics, particularly in functional analysis and topology, closed graph is a property of functions. A function f : X → Y between topological spaces has a closed graph if its graph is a closed subset of the product space X × Y. A related property is open graph. This property is studied because there are many theorems, known as closed graph theorems, giving conditions under which a function with a closed graph is necessarily continuous. One particularly well-known class of closed graph theorems are the closed graph theorems in functional analysis.
  • 5.1K
  • 18 Oct 2022
Topic Review
Types of Aluminium Matrix Composites
Al alloy has very attractive properties required in the production of aerospace, automotive, electrical and electronic, sports and recreational components/equipment. Its low strength and low wear resistance have challenged its applications in some other critical industrial utilities. Nonetheless, the invention of metal composites has removed such barriers. The addition of one or more reinforcements to Al has helped in the creation of aluminium matrix composites (AMCs), which has not only increased the global utilization of Al alloy, but has been a major source of global revenue and job. 
  • 5.1K
  • 20 Oct 2022
Topic Review
Restoration Movement
The Restoration Movement (also known as the American Restoration Movement or the Stone-Campbell Movement, and pejoratively as Campbellism) is a Christian movement that began on the United States frontier during the Second Great Awakening (1790–1840) of the early 19th century. The pioneers of this movement were seeking to reform the church from within and sought "the unification of all Christians in a single body patterned after the church of the New Testament.":54 Especially since the mid-20th century, members of these churches do not identify as Protestant but simply as Christian.:213 The Restoration Movement developed from several independent strands of religious revival that idealized early Christianity. Two groups, which independently developed similar approaches to the Christian faith, were particularly important. The first, led by Barton W. Stone, began at Cane Ridge, Kentucky, and identified as "Christians". The second began in western Pennsylvania and Virginia (now West Virginia) and was led by Thomas Campbell and his son, Alexander Campbell, both educated in Scotland; they eventually used the name "Disciples of Christ". Both groups sought to restore the whole Christian church on the pattern set forth in the New Testament, and both believed that creeds kept Christianity divided. In 1832 they joined in fellowship with a handshake. Among other things, they were united in the belief that Jesus is the Christ, the Son of God; that Christians should celebrate the Lord's Supper on the first day of each week; and that baptism of adult believers by immersion in water is a necessary condition for salvation. Because the founders wanted to abandon all denominational labels, they used the biblical names for the followers of Jesus.:27 Both groups promoted a return to the purposes of the 1st-century churches as described in the New Testament. One historian of the movement has argued that it was primarily a unity movement, with the restoration motif playing a subordinate role.:8 The Restoration Movement has since divided into multiple separate groups. There are three main branches in the U.S.: the Churches of Christ, the unaffiliated Christian Church/Church of Christ congregations, and the Christian Church (Disciples of Christ). Some characterize the divisions in the movement as the result of the tension between the goals of restoration and ecumenism: the Churches of Christ and unaffiliated Christian Church/Church of Christ congregations resolved the tension by stressing restoration, while the Christian Church (Disciples of Christ) resolved the tension by stressing ecumenism.:383 A number of groups outside the U.S. also have historical associations with this movement, such as the Evangelical Christian Church in Canada and the Churches of Christ in Australia. Because the Restoration Movement lacks any centralized structure, having originated in a variety of places with different leaders, there is no consistent nomenclature for the movement as a whole. The term "Restoration Movement" became popular during the 19th century; this appears to be due to the influence of Alexander Campbell's essays on "A Restoration of the Ancient Order of Things" in the Christian Baptist. The term "Stone-Campbell Movement" emerged towards the end of the 20th century as a way to avoid the difficulties associated with some of the other names that have been used, and to maintain a sense of the collective history of the movement.
  • 5.1K
  • 08 Dec 2022
Topic Review
Humic Substances
Humic substances are a very important part of our soil.  The topic is description of the structure of humic substances using NMR.  The NMR part is divided into two parts, liquid and solid state NMR.  The assignment of NMR spectra are discussed and the structural elements that can be deduced from the spectral information.  Principal Component Analysis is used as a tool to categorize the information.  Structural models are discussed.
  • 5.1K
  • 16 Jul 2024
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.
  • 5.1K
  • 21 Oct 2022
Topic Review
Space Travel Using Constant Acceleration
Constant acceleration is a proposed aspect of most future forms of space travel. It entails that the propulsion system of whatever kind operate continuously with a steady acceleration, rather than the brief impulsive thrusts used by chemical rockets — for the first half of the journey it constantly pushes the spacecraft towards its destination, and for the last half of the journey it constantly uses backthrust, so that the spaceship arrives at the destination at a standstill.
  • 5.1K
  • 11 Oct 2022
Topic Review
Application of Analog-to-Digital Converter in Ultrasonic Imaging System
The ADC, a bridge between the analog world and the digital world, converts the analog signals to digital so that the analog signal in the baseband can be processed by the back-end computer or microprocessor.
  • 5.1K
  • 17 Jan 2022
Topic Review
Borderland
The word “borderland” has many meanings; however, it is most often considered from the geographical and sociological, or, in other words, spatial and cultural perspective. The borderland is an area or a territory located near the border or far away from the centre. Within the borderland, socio-cultural contact takes place between various nations or ethnic groups. This is where the “new people and their culture” are formed. A borderland is sometimes precisely delimited, e.g., based on natural objects such as rivers or mountain ranges, or on administrative attributes. It is, however, most frequently determined on the basis of settlement geography. Its actual area and range are determined by migrations, colonisation, and cultural diversity of its inhabitants .
  • 5.1K
  • 19 Jul 2021
Topic Review
Purple Non-Sulfur Bacteria
Photosynthetic bacteria (PSB) are procaryotes capable of carrying out photosynthesis by converting light energy into chemical energy. These photosynthetic bacteria can either grow in the presence or absence of oxygen (aerobic and anaerobic conditions) and can either use organic or inorganic substances as an electron donor to fix the atmospheric nitrogen (N2) and carbon dioxide (CO2). The purple non-sulfur bacteria belong to the anoxygenic group of PSB, and their major groups include Rhodopseudomonas spp. and Rhodobacter spp. They are naturally present in wastewater ponds, lagoons, lakes, sediments, wetland ecosystems, moist soils, hypersaline systems, and marine ecosystems. They possess versatile metabolic pathways and, therefore, are widely used in the livestock and fisheries industries , in bioremedial methods for heavy metals and sewage, and in biofuel production (electricity or photohydrogen). Studies have also shown that purple non-sulfur bacteria (PNSB) help boost soil fertility when applied directly to the soil, whereas PNSB applied to plants help improve crop growth and yield.
  • 5.1K
  • 14 Oct 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).
  • 5.1K
  • 25 Oct 2022
Topic Review
Synthetic Applications of Lawesson’s Reagent in Organic Synthesis
Lawesson’s reagent (LR) is a well-known classic example of a compound with unique construction and unusual chemical behavior, with a wide range of applications in synthetic organic chemistry. Its main functions were rounded for the thionation of various carbonyl groups in the early days. Now its use can help the chemistry community to understand innovative ideas. These include constructing biologically valuable heterocycles, coupling reactions, and the thionation of natural compounds.
  • 5.1K
  • 27 Nov 2021
Topic Review
Internal Monologue
An internal monologue, also called self-talk, inner speech, inner discourse or internal discourse, is a person's inner voice which provides a running verbal monologue of thoughts while they are conscious. It is usually tied to a person's sense of self. It is particularly important in planning, problem solving, self-reflection, self-image, critical thinking, emotions, and subvocalization (reading in one's head). As a result, it is relevant to a number of mental disorders, such as depression, and treatments like cognitive behavioural therapy which seek to alleviate symptoms by providing strategies to regulate cognitive behaviour. It may reflect both conscious and subconscious beliefs. In some cases people may think of inner speech as coming from an external source, as with schizophrenic auditory hallucinations. Additionally, not everyone has a verbal internal monologue (see § Absence of an internal monologue). The looser flow of thoughts and experiences, verbal or not, is called a stream of consciousness, which can also refer to a related technique in literature. In a theory of child development formulated by Lev Vygotsky, inner speech has a precursor in private speech (talking to oneself) at a young age.
  • 5.1K
  • 15 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.
  • 5.1K
  • 21 Oct 2022
Topic Review
Daihatsu Rocky
The Daihatsu Rocky (Japanese: ダイハツ・ロッキー, Daihatsu Rokkī) is an automobile nameplate used by Daihatsu for their lineup of SUVs. The nameplate was originally used as a ladder frame-based mini SUV that was sold in Japan and some international markets between 1989 and 2002. It was gradually replaced by the introduction of Terios in 1997. Beginning in 2019, the Rocky nameplate returned to Japan as a subcompact crossover SUV that replaces the Be‣go and is also rebadged and sold under Toyota brand as the Toyota Raize (Japanese: トヨタ・ライズ, Toyota Raizu).
  • 5.1K
  • 27 Oct 2022
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.
  • 5.1K
  • 24 Nov 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
  • 5.1K
  • 02 Nov 2020
  • Page
  • of
  • 2729
Featured Entry Collections
>>

Featured Reprints

>>
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Medieval Royal Iconography
Academic Video Service
Feedback