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:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Extreme Points of Earth
This is a list of extreme points of Earth, the geographical locations that are farther north or south than, higher or lower in elevation than, or farthest inland or out to sea from, any other locations on the landmasses, continents or countries. For other lists of extreme points on Earth, including places that hold temperature and weather records, see Extremes on Earth, Lists of extreme points, and List of weather records.
  • 6.5K
  • 30 Sep 2022
Topic Review
Doctor of Engineering
The Doctor of Engineering, or Engineering Doctorate, (abbreviated Eng.D., D.Eng., D.Engr., Dr.Eng., or Dr.-Ing.) is a degree awarded on the basis of advanced study and research in engineering and applied sciences. In most countries, it is a terminal research doctorate. A DEng/EngD is equivalent to a PhD in engineering, but different in that it has a solid industrial base and an additional taught element. The DEng/EngD along with the PhD represents the highest academic qualification in engineering, and the successful completion of either in engineering is generally required to gain employment as a full-time, tenure-track university professor or postdoctoral researcher in the field. Individuals can use the academic title doctor, which is often represented via the English honorific "Dr”. DEng/EngD candidates submit a significant project, typically referred to as a thesis or praxis, consisting of a body of original applied research that may be in principle worthy of publication in a peer-reviewed journal. Candidates must defend this work before a panel of expert examiners called a thesis or dissertation committee.
  • 6.5K
  • 20 Oct 2022
Topic Review
Extraction Methods for Anthocyanins
Anthocyanins are considered high added-value compounds due to their sensory qualities, colors, and nutritional properties; they are considered bioactive ingredients. They are found in high concentrations in many by-products across the food industry. At present, expensive raw materials and production technologies make the extraction of natural anthocyanins relatively expensive.
  • 6.5K
  • 18 Feb 2022
Topic Review
Power Electronic Converters in Electric Vehicle Applications
In the electric vehicle (EV) powertrain, all the electric input sources are connected to a HV–DC bus by an individual DC–DC converter, and the output three-phase electric motor (EM), i.e., the main load of the EV, is powered from this HV–DC bus through a three-phase inverter which drives the EM. Here, the voltage level of this HV–DC bus of the EV is around 400–750 V. Moreover, moving the EV via an EM from electric batteries, a DC–DC voltage is required because the batteries’ output voltage is much lower than the required voltage of EM. A traction inverter is needed to drive the EM by converting the DC batteries into variable-frequency AC. However, a disagreement could be made for stepping up the output AC voltage level of the inverter by utilizing a high-voltage transformer instead of a DC–DC converter. This is due to its having several essential advantages, such as reliability, cost-effectiveness, compact size, and lightweight DC–DC converters appear to be excellent candidates for EVs and HEVs powertrains.
  • 6.5K
  • 10 Jan 2023
Topic Review
Luffa Natural Fiber Composites
Natural fiber composites (NFCs) are an evolving area in polymer sciences. Fibers extracted from natural sources hold a wide set of advantages such as negligible cost, significant mechanical characteristics, low density, high strength-to-weight ratio, environmental friendliness, recyclability, etc. Luffa cylindrica, also termed luffa gourd or luffa sponge, is a natural fiber that has a solid potential to replace synthetic fibers in composite materials in diverse applications like vibration isolation, sound absorption, packaging, etc. Recently, many researches have involved luffa fibers as a reinforcement in the development of NFC, aiming to investigate their performance in selected matrices as well as the behavior of the end NFC.
  • 6.5K
  • 25 Sep 2020
Topic Review
G protein-coupled receptor in hepatocytes
G protein-coupled receptors (GPCRs) are cell surface receptors that mediate the function of extracellular ligands. Understanding how GPCRs work at the molecular level has important therapeutic implications, as 30-40% of the drugs currently in clinical use mediate therapeutic effects by acting on GPCRs. Like many other cell types, hepatocyte's function is regulated by GPCRs. A better understanding of the metabolic role of GPCRs in hepatocytes, the dominant constituent cells of the liver, could lead to the development of novel drugs that are clinically useful for the treatment of various metabolic diseases, including Type 2 diabetes, NAFLD, and NASH. 
  • 6.5K
  • 06 Nov 2020
Topic Review
Load Frequency Control System
Power systems are complex systems that have great importance to socio-economic development due to the fact that the entire world relies on the electric network power supply for day-to-day life. Therefore, for the stable operation of power systems, several protection and control techniques are necessary. Among various power system controls, the load frequency control (LFC) is the most time-consuming control mechanism of power systems due to the involvement of mechanical parts. As the control algorithms of frequency stabilization deliver control signals in the timescale of seconds, LFC systems cannot handle complicated data validation algorithms, making them more vulnerable to disturbances and cyber-attacks. Hence advanced research is highly encouraged in the field of development of attack resilient frequency stabilization techniques and in the area of cyber-security of LFC systems.
  • 6.5K
  • 26 Oct 2020
Topic Review
Idealism in International Relations
Idealism in foreign policy holds that a state should make its internal political philosophy the goal of its foreign policy. For example, an idealist might believe that ending poverty at home should be coupled with tackling poverty abroad. U.S. President Woodrow Wilson was an early advocate of idealism. Wilson's idealism was a precursor to liberal international relations theory, which would arise amongst the "institution-builders" after World War II. It particularly emphasized the ideal of American exceptionalism. More generally, Michael W. Doyle describes idealism as based on the belief that other nations' stated good intentions can be relied on, whereas Realism holds that good intentions are in the long run subject to the security dilemma described by John H. Herz. Hedley Bull wrote: By the 'idealists' we have in mind writers such as Sir Alfred Zimmern, S. H. Bailey, Philip Noel-Baker, and David Mitrany in the United Kingdom, and James T. Shotwell, Pitman Potter, and Parker T. Moon in the United States. ... The distinctive characteristic of these writers was their belief in progress: the belief, in particular, that the system of international relations that had given rise to the First World War was capable of being transformed into a fundamentally more peaceful and just world order; that under the impact of the awakening of democracy, the growth of 'the international mind', the development of the League of Nations, the good works of men of peace or the enlightenment spread by their own teaching, it was in fact being transformed; and that their responsibility as students of international relations was to assist this march of progress to overcome the ignorance, the prejudices, the ill-will, and the sinister interests that stood in its way.
  • 6.4K
  • 09 Oct 2022
Topic Review
Hybrid Regime
A hybrid regime is a mixed type of political regime that is often created as a result of an incomplete transition from an authoritarian regime to a democratic one. Hybrid regimes combine autocratic features with democratic ones and can simultaneously hold political repressions and regular elections. The term hybrid regime arises from a polymorphic view of political regimes that opposes the dichotomy of autocracy or democracy. Hybrid regimes are characteristic of resource countries such as petro-states. Those regimes are stable and tenacious. Western researchers analyzing hybrid regimes pay attention to the decorative nature of democratic institutions (elections do not lead to a change of power, different media broadcast government point of view and the opposition in parliament votes the same way as the ruling party, among others), from which it is concluded that authoritarianism is the basis of hybrid regimes. However, hybrid regimes also imitate dictatorship while having a relatively lower level of violence.
  • 6.4K
  • 18 Nov 2022
Topic Review
Frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally without tail in Ancient Greek). The oldest fossil "proto-frog" Triadobatrachus is known from the Early Triassic of Madagascar , but molecular clock dating suggests their split from other amphibians may extend further back to the Permian, 265 million years ago. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest. Frogs account for around 88% of extant amphibian species. They are also one of the five most diverse vertebrate orders. Warty frog species tend to be called toads, but the distinction between frogs and toads is informal, not from taxonomy or evolutionary history. An adult frog has a stout body, protruding eyes, anteriorly-attached tongue, limbs folded underneath, and no tail (the tail of tailed frogs is an extension of the male cloaca). Frogs have glandular skin, with secretions ranging from distasteful to toxic. Their skin varies in colour from well-camouflaged dappled brown, grey and green to vivid patterns of bright red or yellow and black to show toxicity and ward off predators. Adult frogs live in fresh water and on dry land; some species are adapted for living underground or in trees. Frogs typically lay their eggs in water. The eggs hatch into aquatic larvae called tadpoles that have tails and internal gills. They have highly specialized rasping mouth parts suitable for herbivorous, omnivorous or planktivorous diets. The life cycle is completed when they metamorphose into adults. A few species deposit eggs on land or bypass the tadpole stage. Adult frogs generally have a carnivorous diet consisting of small invertebrates, but omnivorous species exist and a few feed on plant matter. Frog skin has a rich microbiome which is important to their health. Frogs are extremely efficient at converting what they eat into body mass. They are an important food source for predators and part of the food web dynamics of many of the world's ecosystems. The skin is semi-permeable, making them susceptible to dehydration, so they either live in moist places or have special adaptations to deal with dry habitats. Frogs produce a wide range of vocalizations, particularly in their breeding season, and exhibit many different kinds of complex behaviors to attract mates, to fend off predators and to generally survive. Frogs are valued as food by humans and also have many cultural roles in literature, symbolism and religion. They are also seen as environmental bellwethers, with declines in frog populations often viewed as early warning signs of environmental damage. Frog populations have declined significantly since the 1950s. More than one third of species are considered to be threatened with extinction and over 120 are believed to have become extinct since the 1980s. The number of malformations among frogs is on the rise and an emerging fungal disease, chytridiomycosis, has spread around the world. Conservation biologists are working to understand the causes of these problems and to resolve them.
  • 6.4K
  • 19 Oct 2022
  • Page
  • of
  • 5488
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Video Production Service
Feedback