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Topic Review
Gadget (Computer Science)
In computational complexity theory, a gadget is a subset of a problem instance that simulates the behavior of one of the fundamental units of a different computational problem. Gadgets are typically used to construct reductions from one computational problem to another, as part of proofs of NP-completeness or other types of computational hardness. The component design technique is a method for constructing reductions by using gadgets. (Szabó 2009) traces the use of gadgets to a 1954 paper in graph theory by W. T. Tutte, in which Tutte provided gadgets for reducing the problem of finding a subgraph with given degree constraints to a perfect matching problem. However, the "gadget" terminology has a later origin, and does not appear in Tutte's paper.
  • 2.0K
  • 18 Oct 2022
Topic Review
Pterygium (Conjunctiva)
A pterygium is a pinkish, triangular tissue growth on the cornea of the eye. It typically starts on the cornea near the nose. It may slowly grow but rarely grows so large that it covers the pupil and impairs vision. Often both eyes are involved. The cause is unclear. It appears to be partly related to long term exposure to UV light and dust. Genetic factors also appear to be involved. It is a benign growth. Other conditions that can look similar include a pinguecula, tumor, or Terrien's marginal corneal degeneration. Prevention may include wearing sunglasses and a hat if in an area with strong sunlight. Among those with the condition, an eye lubricant can help with symptoms. Surgical removal is typically only recommended if the ability to see is affected. Following surgery a pterygium may recur in around half of cases. The frequency of the condition varies from 1% to 33% in various regions of the world. It occurs more commonly among males than females and in people who live closer to the equator. The condition becomes more common with age. The condition has been described since at least 1000 BC.
  • 2.0K
  • 19 Oct 2022
Topic Review
Impulsivity
In psychology, impulsivity (or impulsiveness) is a tendency to act on a whim, displaying behavior characterized by little or no forethought, reflection, or consideration of the consequences. Impulsive actions are typically "poorly conceived, prematurely expressed, unduly risky, or inappropriate to the situation that often result in undesirable consequences," which imperil long-term goals and strategies for success. Impulsivity can be classified as a multifactorial construct. A functional variety of impulsivity has also been suggested, which involves action without much forethought in appropriate situations that can and does result in desirable consequences. "When such actions have positive outcomes, they tend not to be seen as signs of impulsivity, but as indicators of boldness, quickness, spontaneity, courageousness, or unconventionality" Thus, the construct of impulsivity includes at least two independent components: first, acting without an appropriate amount of deliberation, which may or may not be functional; and second, choosing short-term gains over long-term ones. Impulsivity is both a facet of personality and a major component of various disorders, including ADHD, substance use disorders, bipolar disorder, antisocial personality disorder, and borderline personality disorder. Abnormal patterns of impulsivity have also been noted instances of acquired brain injury and neurodegenerative diseases. Neurobiological findings suggest that there are specific brain regions involved in impulsive behavior, although different brain networks may contribute to different manifestations of impulsivity, and that genetics may play a role. Many actions contain both impulsive and compulsive features, but impulsivity and compulsivity are functionally distinct. Impulsivity and compulsivity are interrelated in that each exhibits a tendency to act prematurely or without considered thought and often include negative outcomes. Compulsivity may be on a continuum with compulsivity on one end and impulsivity on the other, but research has been contradictory on this point. Compulsivity occurs in response to a perceived risk or threat, impulsivity occurs in response to a perceived immediate gain or benefit, and, whereas compulsivity involves repetitive actions, impulsivity involves unplanned reactions. Impulsivity is a common feature of the conditions of gambling and alcohol addiction. Research has shown that individuals with either of these addictions discount delayed money at higher rates than those without, and that the presence of gambling and alcohol abuse lead to additive effects on discounting.
  • 2.0K
  • 25 Oct 2022
Topic Review
Lactase Persistence
In humans, the ability to digest milk lactose is conferred by a β-galactosidase enzyme called lactase-phlorizin hydrolase (LPH). The LPH enzyme is encoded by the lactase (LCT) gene, located on the chromosome 2q21. Exclusively expressed in the small intestine, in the apical part of microvilli within the brush border membrane of enterocytes, the LPH enzyme reaches the highest levels of activity during the nursing period. After the weaning phase, however, in the majority of humans, the activity of LPH declines rapidly because of a decrease in the levels of the enzyme, and this trait is known as lactase non-persistence (LNP). As a consequence of LNP, the majority of humans are unable to digest lactose during adulthood, and some suffer clinical complications when they consume it. It has been estimated that approximately two-thirds of humans are LNP worldwide. In the remaining third, however, there are individuals with the ability to digest milk and other lactose-rich dairy products during adulthood. This trait is known as lactase persistence (LP), and is particularly common in descendants from populations that have traditionally practiced cattle domestication.
  • 2.0K
  • 09 Sep 2020
Topic Review
Health, Nutrition, and Food Literacy
Nutrition and food literacy are two important concepts that are often used interchangeably, but they are not synonymous. Nutrition refers to the study of how food affects the body, while food literacy refers to the knowledge, skills, and attitudes necessary to make informed decisions about food and its impact on health. Despite the growing awareness of the importance of food literacy, food illiteracy remains a global issue, affecting people of all ages, backgrounds, and socioeconomic status. Food illiteracy has serious health implications as it contributes to health inequities, particularly among vulnerable populations. 
  • 2.0K
  • 20 Nov 2023
Topic Review
Biological Medicinal Products
Definitions of biological medicinal products (BMPs) vary depending on the source. BMPs are manufactured using complex biological/biotechnological processes involving living cell lines, tissues and organisms such as microorganisms, plants, humans and even animals.
  • 2.0K
  • 25 Dec 2020
Topic Review
Tethered-Bilayer Lipid Membranes
Membrane proteins (MPs) are essential for cellular functions. Understanding the functions of MPs is crucial as they constitute an important class of drug targets. However, MPs are a challenging class of biomolecules to analyze because they cannot be studied outside their native environment. Their structure, function and activity are highly dependent on the local lipid environment, and these properties are compromised when the protein does not reside in the cell membrane. Mammalian cell membranes are complex and composed of different lipid species. Model membranes have been developed to provide an adequate environment to envisage MP reconstitution. Among them, tethered-Bilayer Lipid Membranes (tBLMs) appear as the best model because they allow the lipid bilayer to be decoupled from the support. Thus, they provide a sufficient aqueous space to envisage the proper accommodation of large extra-membranous domains of MPs, extending outside. Additionally, as the bilayer remains attached to tethers covalently fixed to the solid support, they can be investigated by a wide variety of surface-sensitive analytical techniques.
  • 2.0K
  • 03 Jun 2021
Topic Review
Mitochondrial Protein Import
Mitochondria play a critical role in providing energy, maintaining cellular metabolism, and regulating cell survival and death. To carry out these crucial functions, mitochondria employ more than 1500 proteins, distributed between two membranes and two aqueous compartments. An extensive network of dedicated proteins is engaged in importing and sorting these nuclear-encoded proteins into their designated mitochondrial compartments. Defects in this fundamental system are related to a variety of pathologies, particularly engaging the most energy-demanding tissues.
  • 2.0K
  • 06 Apr 2022
Topic Review
Retail Price Index
In the United Kingdom, the Retail Prices Index or Retail Price Index (RPI) is a measure of inflation published monthly by the Office for National Statistics. It measures the change in the cost of a representative sample of retail goods and services. As the RPI was held not to meet international statistical standards, since 2013 the Office for National Statistics no longer classifies it as a "national statistic", emphasising the Consumer Price Index instead. However, as of 2018 the UK Treasury still uses the RPI measure of inflation for various index-linked tax rises.
  • 2.0K
  • 27 Sep 2022
Topic Review
Atari Portfolio
The Atari Portfolio (Atari PC Folio) is an IBM PC-compatible palmtop PC, released by Atari Corporation in June 1989. This makes it the world's first palmtop computer.
  • 2.0K
  • 10 Nov 2022
Topic Review
Plasma-Activated Water Treatment in Agriculture
The unique properties of physical plasma and its ability to operate at atmospheric pressure make it an attractive technology for numerous scientific and industrial applications, ranging from medicine and agriculture to electronics and materials science. For example, this technology has proven to be a simple and low-cost approach for nanoparticle synthesis or an effective surface modification agent to produce superhydrophobic and superoleophilic films for oil-water separation and self-cleaning. 
  • 2.0K
  • 23 Oct 2023
Topic Review
Thymic Epithelial Cells
The thymus is a primary lymphoid organ derived from the endoderm of the 3rd pharyngeal pouch implicated in the maturation of thymocytes and, therefore, key for establishing the immune surveillance. This organ does not contain self-renewing lymphoid precursor cells and therefore, is colonized by lymphoid precursors coming either from the fetal liver through mesenchyme or from the adult bone marrow via the blood vessels [1]. Within the thymus, the developing thymocytes move throughout a 3D thymic epithelial (TE) network, interacting with the thymic epithelial cells (TECs) of two histologically different compartments: the cortex and the medulla [2].
  • 2.0K
  • 26 Oct 2020
Topic Review
Physicochemical Properties and Activities of Catechins
Catechins are bioactive polyphenols and are typically isolated from green tea (Camellia sinensis L.) and gambir leaves (Uncaria gambir Roxb). There are a few types of catechins which possess the flavan-3-ol structure consisting of two benzene rings, a heterocycle dihydropyran, and a hydroxyl.
  • 2.0K
  • 22 Feb 2024
Topic Review
Biometal
Biometals are metals normally present, in small but important and measurable amounts, in biology, biochemistry, and medicine. The metals copper, zinc, iron, and manganese are examples of metals that are essential for the normal functioning of most plants and the bodies of most animals, such as the human body. A few (calcium, potassium, sodium) are present in relatively larger amounts, whereas most others are trace metals, present in smaller but important amounts (the image shows the percentages for humans). Approximately 2/3 of the existing periodic table is composed of metals with varying properties, accounting for the diverse ways in which metals (usually in ionic form) have been utilized in nature and medicine.
  • 2.0K
  • 10 Oct 2022
Biography
Franz Josef Giessibl
Franz Josef Gießibl (born 27 May 1962 in Amerang) is a Germany physicist and university professor at the University of Regensburg. Giessibl studied physics from 1982 to 1987 at the Technical University of Munich and at Eidgenössische Technischen Hochschule Zürich. He received a diploma in experimental physics in 1988 with Professor Gerhard Abstreiter and continued with a PhD in physics wit
  • 2.0K
  • 12 Dec 2022
Topic Review
African Swine Fever Virus
African swine fever virus (ASFV) is the causative agent of the epidemic of African swine fever (ASF), with virulent strains having a mortality rate of up to 100% and presenting devastating impacts on animal farming. ASFV is the only known arbovirus in the Nucleoplasmic Large DNA Virus (NCLDV) family. It has an icosahedral structure and envelope with a diameter of 200nm. The length of the genome varies between 170 and 190 kbp, encoding 151 to 167 open reading frames (ORF), which are closely spaced along two strands of viral DNA and separated by short intergenic regions.
  • 2.0K
  • 09 Mar 2022
Topic Review
Food Security Interventions among Refugees
There are 26 million refugees globally, with as many as 80% facing food insecurity irrespective of location. Humanitarian agencies continually provide assistance and evaluate their interventions in areas of refugee crisis. Researchers should adopt a standard feasible food security assessment tool which is needed to assess the effectiveness of interventions across locations and countries to develop best practices based on comparative results.
  • 2.0K
  • 24 Mar 2022
Topic Review
Drives of Urban Village Redevelopment
Urban village redevelopment generally refers to the demolition and rehabilitation of urban village buildings, involving several complicated processes, including urban space rebuilding, land ownership transformation, land value increment, and spatial benefit redistribution, which have attracted serious attention from the academic community in the past decades. At least three main processes from demand, supply and state interventions perspectives have driven urban village redevelopment in China.
  • 2.0K
  • 21 Apr 2022
Topic Review
Dietary Recommendations for Twin Pregnancy
Recommendations for nutrition and the use of dietary supplements for pregnant women are updated on regular basis but it remains to be seen to what extent they may be applicable in twin pregnancies. Over the past 30 years, there has been a considerable increase in the number of multiple pregnancies worldwide, which mainly applies to dizygotic pregnancies. In the USA, in 2009 compared to the 1980s, the number of twin pregnancies increased by 76%; the situation was similar in Australia (66%). A multiple pregnancy is associated with an increased risk of its abnormal course. This mostly applies to pre-eclampsia, hypertension, diabetes, iron-deficiency anemia and pre-term birth that affects 50–60% of twin pregnancies. 
  • 2.0K
  • 26 Apr 2022
Topic Review
Google Earth Engine and Artificial Intelligence
Remote sensing (RS) plays an important role gathering data in many critical domains (e.g., global climate change, risk assessment and vulnerability reduction of natural hazards, resilience of ecosystems, and urban planning). Retrieving, managing, and analyzing large amounts of RS imagery poses substantial challenges. Google Earth Engine (GEE) provides a scalable, cloud-based, geospatial retrieval and processing platform. GEE also provides access to the vast majority of freely available, public, multi-temporal RS data and offers free cloud-based computational power for geospatial data analysis. Artificial intelligence (AI) methods are a critical enabling technology to automating the interpretation of RS imagery, particularly on object-based domains, so the integration of AI methods into GEE represents a promising path towards operationalizing automated RS-based monitoring programs. 
  • 2.0K
  • 15 Aug 2022
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