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Topic Review
Novel 1,2,4-Oxadiazole Derivatives
Five-membered 1,2,4-oxadiazole heterocyclic ring has received considerable attention because of its unique bioisosteric properties and an unusually wide spectrum of biological activities. Thus, it is a perfect framework for the novel drug development. After a century since the 1,2,4-oxadiazole have been discovered, the uncommon potential attracted medicinal chemists’ attention, leading to the discovery of a few presently accessible drugs containing 1,2,4-oxadiazole unit. It is worth noting that the interest in a 1,2,4-oxadiazoles’ biological application has been doubled in the last fifteen years. Herein, after a concise historical introduction, we present a comprehensive overview of the recent achievements in the synthesis of 1,2,4-oxadiazole-based compounds and the major advances in their biological applications in the period of the last five years as well as brief remarks on prospects for further development.
  • 6.3K
  • 03 Jun 2021
Topic Review
Philosophy of History
Philosophy of history is the philosophical study of history and the past. The term was coined by Voltaire.
  • 6.3K
  • 19 Oct 2022
Topic Review
Solar Photovoltaic Systems Faults
This entry provides an overview of common Solar PV system faults.
  • 6.3K
  • 17 Dec 2021
Topic Review
Euro Health Consumer Index
Euro Health Consumer Index (EHCI) is a comparison of European health care systems based on waiting times, results, and generosity. The information is presented as a graphic index. EHCI was produced 2005–2009 and 2012–2016 by Health Consumer Powerhouse. The 2014 ranking included 37 countries measured by 48 indicators. It claims to measure the "consumer friendliness" of healthcare systems. It does not claim to measure which European state has the best healthcare system, but it does produce specialist Indexes on Diabetes, Cardiac Care, HIV, Headache and Hepatitis. In 2006 France was the champion with 768 points out of 1000. In the 2015 results the same performance would have given the 13th position among 35 countries because of the widespread improvements in standards. While no bias in favour of any health system was alleged, the index was criticised in the British Medical Journal by Martin McKee and others from the European Observatory on Health Systems and Policies in February 2016. Points they made included: A survey by the Centre for Population Change in 2019 produced results consistent with the index.
  • 6.3K
  • 09 Nov 2022
Topic Review
Cousin
Most generally, in the lineal kinship system used in the English-speaking world, a cousin is a type of familial relationship in which two relatives are two or more familial generations away from their most recent common ancestor. Commonly, "cousin" refers to a first cousin – a relative of the same generation whose most recent common ancestor with the subject is a grandparent. Degrees and removals are separate measures used to more precisely describe the relationship between cousins. Degree measures the separation, in generations, from the most recent common ancestor(s) to a parent of one of the cousins (whichever is closest), while removal measures the difference in generations between the cousins themselves, relative to their most recent common ancestor(s). To illustrate usage, a second cousin is a cousin with a degree of two; there are three (not two) generations from the common ancestor(s). When the degree is not specified, first cousin is assumed. A cousin "once removed" is a cousin with one removal. When the removal is not specified, no removal is assumed. Various governmental entities have established systems for legal use that can precisely specify kinship with common ancestors any number of generations in the past; for example, in medicine and in law, a first cousin is a type of third-degree relative.
  • 6.3K
  • 25 Oct 2022
Topic Review
Fennec Fox
The Fennec Fox (Vulpes zerda) is a small, desert-dwelling fox species known for its distinctive large ears, which serve to dissipate heat and detect prey underground. Native to the arid regions of North Africa, particularly the Sahara Desert, the Fennec Fox is supremely adapted to its harsh environment, with specialized physiological and behavioral traits that enable survival in extreme conditions. Despite its diminutive size, the Fennec Fox is a highly efficient predator, preying on insects, small mammals, and birds, and its charming appearance has made it a popular subject of fascination and conservation efforts worldwide
  • 6.3K
  • 14 Apr 2025
Topic Review
siRNA Structure, Function and Delivery
siRNA is a double-stranded RNA molecule with 21- and 22-nucleotide generated by ribonuclease III cleavage from longer double-stranded RNA (dsRNAs). After binding to the RNA-induced silencing complex (RISC) in the cytoplasm, the sense strand of siRNA undergoes ejection, while the antisense strand of siRNA targets the complementary messenger RNA (mRNA). 
  • 6.3K
  • 20 May 2022
Topic Review
The Acquisition of Negation
Although negation in natural languages is a complex and heterogeneous phenomenon, the first instances of linguistic negation appear in children’s speech quite early, by 18 and 24 months of life. Nevertheless, its acquisition is a gradual and challenging process, as it takes time for children to fully grasp the semantic meanings of the different negative words to be able to use them correctly across different sentential contexts. Moreover, in order to understand how to negate a sentence, children must also learn how negation can have scope over different parts of the sentences, leaving the others unaffected. The picture becomes even more complicated for children when multiple negative structures come into play, in which the negative meaning is conveyed by the combination of two (or more) negative elements. The interpretation of these complex syntactic constructions is indeed not always straightforward since a different arrangement of the same negative elements may yield different semantic interpretations of the same sentence.
  • 6.3K
  • 16 Jun 2022
Topic Review
Perception of Artificial Intelligence by Students
Artificial Intelligence (AI) has become an integral part of people's daily lives and is available on all platforms, from smart homes to smartphones and autonomous cars. Students of economics and business studies at different levels of study have the differences in various aspects of the perception of artificial intelligence. Current college students will soon join a job market where proficiency in working with, developing, and managing AI will be necessary for many positions. Studying AI-related courses has become a necessary trend that offers significant benefits for students’ future career development 
  • 6.3K
  • 16 Jun 2023
Topic Review
E-reader
An e-reader, also called an e-book reader or e-book device, is a mobile electronic device that is designed primarily for the purpose of reading digital e-books and periodicals. Any device that can display text on a screen may act as an e-reader; however, specialized e-reader devices may optimize portability, readability, and battery life for this purpose. Their main advantage over printed books is portability. This is because an e-reader is capable of holding thousands of books while weighing less than one book, and the convenience provided due to add-on features.
  • 6.3K
  • 21 Oct 2022
Topic Review
Apoptosis
Apoptosis is a multistep process that involves two major pathways to trigger a cascade of events leading to the fragmentation of chromatin, nuclear membrane, and cell shrinkage. However, when this physiological process tended to be dysregulated, many pathological transformations happen to develop cancer.
  • 6.3K
  • 23 Jun 2021
Topic Review
Militarization of Police
The militarization of police is the use of military equipment and tactics by law enforcement officers. This includes the use of armored personnel carriers (APCs), assault rifles, submachine guns, flashbang grenades, grenade launchers, sniper rifles, and SWAT (special weapons and tactics) teams. The militarization of law enforcement is also associated with intelligence agency–style information gathering aimed at the public and political activists and with a more aggressive style of law enforcement. Criminal justice professor Peter Kraska has defined militarization of police as "the process whereby civilian police increasingly draw from, and pattern themselves around, the tenets of militarism and the military model". Observers have noted the militarizing of the policing of protests. Since the 1970s, riot police have fired at protesters using guns with rubber bullets or plastic bullets. Tear gas, which was developed by the United States Army for riot control in 1919, is still widely used against protesters. The use of tear gas in warfare is prohibited by various international treaties that most states have signed; however, its law enforcement or military use for domestic or non-combat situations is permitted. Concerns about the militarization of police have been raised by both ends of the political spectrum in the United States , with both the libertarian Cato Institute and the American Civil Liberties Union (ACLU) voicing criticisms of the practice. The Fraternal Order of Police has spoken out in favor of equipping law enforcement officers with military equipment, claiming that it increases the officers' safety and enables them to protect members of the public and other first responders (e.g., firefighters and emergency medical services personnel). However, a 2017 study showed that police forces which received military equipment were more likely to have violent encounters with the public, regardless of local crime rates. A 2018 study found that militarized police units in the United States were more frequently deployed to communities with large shares of African-Americans, even after controlling for local crime rates. Many countries also have a gendarmerie, which is a military force with law enforcement duties among the civilian population. France classifies some weapons as "intermediary force weapons" such as its LBD 40 refitted version of the Swiss B&T GL06 military grenade launcher, which is used in riot police situations or against individual persons in more specific interventions. While not having the full power of military guns, some weapons are heavier than regular police weaponry and are still lethal. These are often referred to with the "limited lethality" appellation.
  • 6.3K
  • 11 Oct 2022
Topic Review
Artificial Island Developments
Artificial island development (AID) to tackle rampant urbanization on scarce land puts all marine biodiversity at huge risk and is recognized as a global conservation issue worldwide.
  • 6.3K
  • 16 May 2022
Topic Review
Allosaurus
Allosaurus (/ˌæləˈsɔːrəs/) is a genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic epoch (Kimmeridgian to late Tithonian). The name "Allosaurus" means "different lizard" alluding to its unique (at the time of its discovery) concave vertebrae. It is derived from the Greek ἄλλος (allos) ("different, other") and σαῦρος (sauros) ("lizard / generic reptile"). The first fossil remains that could definitively be ascribed to this genus were described in 1877 by paleontologist Othniel Charles Marsh. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles. Allosaurus was a large bipedal predator. Its skull was light, robust and equipped with dozens of sharp, serrated teeth. It averaged 8.5 meters (28 ft) in length for A. fragilis, with the largest specimens estimated as being 9.7 metres (32 ft) long. Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long and heavily muscled tail. It is classified as an allosaurid, a type of carnosaurian theropod dinosaur. The genus has a complicated taxonomy, and includes at least three valid species, the best known of which is A. fragilis. The bulk of Allosaurus remains have come from North America's Morrison Formation, with material also known from Portugal. It was known for over half of the 20th century as Antrodemus, but a study of the abundant remains from the Cleveland-Lloyd Dinosaur Quarry brought the name "Allosaurus" back to prominence and established it as one of the best-known dinosaurs. As the most abundant large predator in the Morrison Formation, Allosaurus was at the top of the food chain, probably preying on contemporaneous large herbivorous dinosaurs, and perhaps other predators. Potential prey included ornithopods, stegosaurids, and sauropods. Some paleontologists interpret Allosaurus as having had cooperative social behavior, and hunting in packs, while others believe individuals may have been aggressive toward each other, and that congregations of this genus are the result of lone individuals feeding on the same carcasses.
  • 6.3K
  • 16 Nov 2022
Topic Review
Climate Change and Russian Agriculture
Russian weather trends such as winter softening and increase in summer heat have a significant but opposite effect on yields. An interesting finding is a significant and mostly positive influence of global climatic variables, such as the CO2 concentration, El Niño and La Niña events on both harvests and yields. Although technological factors are the main drivers of growth in Russian agricultural performance over the past 20 years, we found a strong positive effect on yield and gross harvest only for mineral fertilizers. The influence of the other variables is mixed, which is mainly due to data quality and aggregation errors.
  • 6.3K
  • 24 Jan 2022
Topic Review
Clays and the Origin of Life
Clays are able to replicate and drive the evolution of metabolism; they have the catalytic ability to synthesize monomers (amino acids, nucleotides and so on) and polymerize them, resulting in RNA–peptide worlds in which RNA replicates (genes) and, in cooperation with coded peptides, drives the evolution of the cell. 
  • 6.3K
  • 25 Feb 2022
Topic Review
Pan-Tompkins Algorithm
The Pan-Tompkins algorithm is commonly used to detect QRS complexes in electrocardiographic signals (ECG). The QRS complex represents the ventricular depolarization and the main spike visible in an ECG signal (see figure). This feature makes it particularly suitable for measuring heart rate, the first way to assess the heart health state. In the first derivation of Einthoven of a physiological heart, the QRS complex is composed by a downward deflection (Q wave), an high upward deflection (R wave) and a final downward deflection (S wave). The Pan-Tompkins algorithm applies a series of filters to highlight the frequency content of this rapid heart depolarization and removes the background noise. Then, it squares the signal to amplify the QRS contribute. Finally, it applies adaptive thresholds to detect the peaks of the filtered signal. The algorithm was proposed by Jiapu Pan and Willis J. Tompkins in 1985, in the journal IEEE Transactions on Biomedical Engineering . The performance of the method was tested on an annotated arrhythmia database (MIT/BIH) and evaluated also in presence of noise. Pan and Tompkins reported that the 99.3 percent of QRS complexes was correctly detected.
  • 6.2K
  • 24 Oct 2022
Topic Review
Biorhythm
A biorhythm (from Greek βίος – bios, "life" and ῥυθμός – rhuthmos, "any regular recurring motion, rhythm") is an attempt to predict various aspects of a person's life through simple mathematical cycles. The theory was developed by Wilhelm Fliess in the late 19th century, and was popularized in the United States in late 1970s. Scientific analysis shows that biorhythms have no more predictive power than chance, providing no evidence for their existence. "The theory of biorhythms is a theory that claims our daily lives are significantly affected by rhythmic cycles."
  • 6.2K
  • 01 Dec 2022
Topic Review
Extended-Range Electric Vehicles
Extended-range electric vehicles (EREVs), commonly known as series hybrid electric vehicles (Series-HEV), have better autonomy than electric vehicles (EV) without range extenders (REs). EREVs can go from one city to another or make long journeys in general.
  • 6.2K
  • 03 Aug 2021
Topic Review
Solar Storm of 1859
The solar storm of 1859 (also known as the Carrington Event) was a powerful geomagnetic storm during solar cycle 10 (1855–1867). A solar coronal mass ejection (CME) hit Earth's magnetosphere and induced the largest geomagnetic storm on record, September 1–2, 1859. The associated "white light flare" in the solar photosphere was observed and recorded by British astronomers Richard C. Carrington (1826–1875) and Richard Hodgson (1804–1872). The storm caused strong auroral displays and wrought havoc with telegraph systems. The now-standard unique IAU identifier for this flare is SOL1859-09-01. A solar storm of this magnitude occurring today would cause widespread electrical disruptions, blackouts and damage due to extended outages of the electrical grid. The solar storm of 2012 was of similar magnitude, but it passed Earth's orbit without striking the planet, missing by nine days.
  • 6.2K
  • 20 Oct 2022
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