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Topic Review
Least Developed Countries
The Least Developed Countries (LDCs) is a list of developing countries that, according to the United Nations, exhibit the lowest indicators of socioeconomic development, with the lowest Human Development Index ratings of all countries in the world. The concept of LDCs originated in the late 1960s and the first group of LDCs was listed by the UN in its resolution 2768 (XXVI) of 18 November 1971. A country is classified among the Least Developed Countries if it meets three criteria: (1) Poverty – adjustable criterion based on GNI per capita averaged over three years. (As of 2018) a country must have GNI per capita less than United States dollar 1,025 to be included on the list, and over $1,230 to graduate from it. (2) Human resource weakness (based on indicators of nutrition, health, education and adult literacy). (3) Economic vulnerability (based on instability of agricultural production, instability of exports of goods and services, economic importance of non-traditional activities, merchandise export concentration, handicap of economic smallness, and the percentage of population displaced by natural disasters). As of 2018, 47 countries are classified as LDC, while five have been upgraded between 1994 and 2017. The WTO recognizes the UN list of LDCs in toto. 
  • 3.2K
  • 17 Oct 2022
Topic Review
Carbon-Burning Process
The carbon-burning process or carbon fusion is a set of nuclear fusion reactions that take place in the cores of massive stars (at least 8 [math]\displaystyle{ \begin{smallmatrix}M \odot\end{smallmatrix} }[/math] at birth) that combines carbon into other elements. It requires high temperatures (> 5×108 K or 50 keV) and densities (> 3×109 kg/m3). These figures for temperature and density are only a guide. More massive stars burn their nuclear fuel more quickly, since they have to offset greater gravitational forces to stay in (approximate) hydrostatic equilibrium. That generally means higher temperatures, although lower densities, than for less massive stars. To get the right figures for a particular mass, and a particular stage of evolution, it is necessary to use a numerical stellar model computed with computer algorithms. Such models are continually being refined based on nuclear physics experiments (which measure nuclear reaction rates) and astronomical observations (which include direct observation of mass loss, detection of nuclear products from spectrum observations after convection zones develop from the surface to fusion-burning regions – known as dredge-up events – and so bring nuclear products to the surface, and many other observations relevant to models).
  • 3.2K
  • 17 Nov 2022
Topic Review
Catalytic Pyrolysis of Plastic Waste
Plastic is a non-degradable material that can persist in the environment for long periods of time. On the other hand, it is a very special material with a great number of advantages: it is affordable, versatile, light, and resistant. Plastic originates from petrochemicals and contains mostly hydrocarbons and some additives, such as antioxidants, flame retardants, and stabilizers, which make the material very bio-undegradable. Pyrolysis can be thermal or catalytic. Thermal pyrolysis requires higher temperatures (from 350 to 900 °C), which can lead to a low molecular weight and low quality products. Gases evolved during pyrolysis have a high calorific value, and could be used in different gas machines and engines for the generation of electricity without any other treatments or modifications. The addition of catalysts overcomes the limitations of thermal pyrolysis, by reducing either the reaction temperature or the time. The addition of catalysts improves conversion, reduces activation energy of pyrolysis, and enhances the fuel quality. The most commonly used catalysts for the pyrolysis of plastics are zeolites, polyciliate components, and clays. Compared to thermal pyrolysis, the catalytic process has the advantage of a lower process temperature, a reduction of solid residues such as carbonized char and volatile fraction, shorter time process, high product selectivity, and high-octane-number products. Zeolite-based catalysts are the best option for the pyrolysis of plastic waste, and for co-pyrolysis of combined plastic waste/biomass.
  • 3.2K
  • 04 Jan 2023
Topic Review
Photolyase
Photolyase is a protein that has various functions, among which is the repair of DNA damaged from exposure to UV rays from the sun.
  • 3.2K
  • 30 Sep 2022
Topic Review
Old-Field Secondary Succession
Ecological succession to determine how plant communities re-assemble after a natural or anthropogenic disturbance has always been an important topic in ecology.
  • 3.2K
  • 20 May 2021
Topic Review
Applications of Biomimetic Propulsion for Underwater Vehicles
Biomimetics and bio-inspiration, distinct yet complementary, both derive insights from nature’s ingenuity in science and engineering. Biomimetics, specifically for underwater vehicles, studies and emulates the efficient shapes and behaviors of aquatic creatures like fishes, dolphins, and whales, leading to innovative underwater vehicle designs with enhanced speed, thrust, maneuverability, and reduced water drag.
  • 3.2K
  • 04 Feb 2024
Topic Review
Students' Union
A students' union, student government, free student union, student senate, students' association, guild of students, or government of student body is a student organization present in many colleges, universities, and high schools. In higher education, the students' union is often accorded its own building on the campus, dedicated to social, organizational activities, representation, and academic support of the membership. In the United States, student union often only refers to a physical building owned by the university with the purpose of providing services for students without a governing body. This building is also referred to as a student activity center, although the Association of College Unions International (largely US-based) has hundreds of campus organizational members. Outside the US, student union and students' union refer to a representative body, as distinct from a student activity centre.
  • 3.2K
  • 01 Dec 2022
Topic Review
Asynchronous Environment Assessment
The emergence and global spread of COVID-19 has disrupted the traditional mechanisms of education throughout the world. Institutions of learning were caught unprepared and this jeopardised the face-to-face method of curriculum delivery and assessment. Teaching institutions have shifted to an asynchronous mode whilst attempting to preserve the principles of integrity, equity, inclusiveness, fairness, ethics, and safety. A framework of assessment that enables educators to utilise appropriate methods in measuring a student’s progress is crucial for the success of teaching and learning, especially in health education that demands high standards and comprises consistent scientific content. 
  • 3.2K
  • 30 Sep 2021
Topic Review
Exercise influence on calcium-phosphorous metabolism
Exercise perturbs homeostasis, alters the levels of circulating mediators and hormones, and increases the demand by skeletal muscles and other vital organs for energy substrates. Exercise also affects bone and mineral metabolism, particularly calcium and phosphate, both of which are essential for muscle contraction, neuromuscular signaling, biosynthesis of adenosine triphosphate (ATP), and other energy substrates. Parathyroid hormone (PTH) is involved in the regulation of calcium and phosphate homeostasis. Understanding the e ects of exercise on PTH secretion is fundamental for appreciating how the body adapts to exercise.
  • 3.2K
  • 26 Aug 2020
Topic Review
Breastfeeding
Breastfeeding, also known as nursing, is the feeding of babies and young children with milk from a woman's breast. Health professionals recommend that breastfeeding begin within the first hour of a baby's life and continue as often and as much as the baby wants. During the first few weeks of life babies may nurse roughly every two to three hours and the duration of a feeding is usually ten to fifteen minutes on each breast. Older children feed less often. Mothers may pump milk so that it can be used later when breastfeeding is not possible. Breastfeeding has a number of benefits to both mother and baby, which infant formula lacks. Deaths of an estimated 820,000 children under the age of five could be prevented globally every year with increased breastfeeding. Breastfeeding decreases the risk of respiratory tract infections and diarrhea, both in developing and developed countries. Other benefits include lower risks of asthma, food allergies, type 1 diabetes, and leukemia. Breastfeeding may also improve cognitive development and decrease the risk of obesity in adulthood. Mothers may feel pressure to breastfeed, but in the developed world children generally grow up normally when bottle fed. Benefits for the mother include less blood loss following delivery, better uterus shrinkage, and less postpartum depression. Breastfeeding delays the return of menstruation and fertility, a phenomenon known as lactational amenorrhea. Long term benefits for the mother include decreased risk of breast cancer, cardiovascular disease, and rheumatoid arthritis. Breastfeeding is less expensive than infant formula. Health organizations, including the World Health Organization (WHO), recommend breastfeeding exclusively for six months. This means that no other foods or drinks other than possibly vitamin D are typically given. After the introduction of foods at six months of age, recommendations include continued breastfeeding until one to two years of age or more. Globally about 38% of infants are only breastfed during their first six months of life. In the United States, about 75% of women begin breastfeeding and about 13% only breastfeed until the age of six months. Medical conditions that do not allow breastfeeding are rare. Mothers who take certain recreational drugs and medications should not breastfeed. Smoking, limited amounts of alcohol, or coffee are not reasons to avoid breastfeeding.
  • 3.2K
  • 11 Nov 2022
Topic Review
Pharmacological Effects of Houttuynia cordata Thunb (H. cordata)
Houttuynia cordata Thunb (H. cordata) is a rhizomatous, herbaceous, and perennial plant widely distributed in Asia. It has multiple chemical constituents, such as alkaloids, essential oils, phenolic acids, and flavonoids used against various health problems. The essential oils and flavonoids are the main components of H. cordata that play an essential role in disease treatment and traditional health care. Moreover, the leaves and stems of H. cordata have a long medicinal history in China. In addition, H. cordata is used against several health issues, such as cold, cough, fever, pneumonia, mumps, and tumors, due to its anti-inflammatory, anti-bacterial, anti-viral, anti-oxidant, and anti-tumor effects.
  • 3.2K
  • 07 Sep 2022
Topic Review
Sierpinski Number
In number theory, a Sierpiński number is an odd natural number k such that [math]\displaystyle{ k \times 2^n + 1 }[/math] is composite for all natural numbers n. In 1960, Wacław Sierpiński proved that there are infinitely many odd integers k which have this property. In other words, when k is a Sierpiński number, all members of the following set are composite: If the form is instead [math]\displaystyle{ k \times 2^n - 1 }[/math], then k is a Riesel number.
  • 3.2K
  • 02 Dec 2022
Topic Review
Polyphenylsulfone Membrane
Polyphenylsulfone (PPSU) membranes are of fundamental importance for many applications such as water treatment, gas separation, energy, electronics, and biomedicine, due to their low cost, controlled crystallinity, chemical, thermal, and mechanical stability. Numerous research studies have shown that modifying surface properties of PPSU membranes influences their stability and functionality. Therefore, the modification of the PPSU membrane surface is a pressing issue for both research and industrial communities.
  • 3.2K
  • 10 Mar 2022
Topic Review
Microalga Haematococcus pluvialis
The freshwater microalga Haematococcus pluvialis is well known as the cell factory for natural astaxanthin, which composes up to 4–7% of its total dry weight. The bioaccumulation of astaxanthin in H. pluvialis cysts seems to be a very complex process that depends on different stress conditions during its cultivation. The red cysts of H. pluvialis develop thick and rigid cell walls under stress growing conditions.
  • 3.2K
  • 03 Mar 2023
Topic Review
Conductive Fibers
As one of the most impressive materials for wearable sensors, conductive fibers can be made from a variety of raw sources via diverse preparation strategies.
  • 3.1K
  • 28 Apr 2022
Topic Review
Mushroom Poisoning
Mushroom poisoning is poisoning resulting from the ingestion of mushrooms that contain toxic substances. Its symptoms can vary from slight gastrointestinal discomfort to death in about 10 days. Mushroom toxins are secondary metabolites produced by the fungus. Mushroom poisoning is usually the result of ingestion of wild mushrooms after misidentification of a toxic mushroom as an edible species. The most common reason for this misidentification is a close resemblance in terms of color and general morphology of the toxic mushrooms species with edible species. To prevent mushroom poisoning, mushroom gatherers familiarize themselves with the mushrooms they intend to collect, as well as with any similar-looking toxic species. The safety of eating wild mushrooms may depend on methods of preparation for cooking.
  • 3.1K
  • 19 Oct 2022
Topic Review
Civil Marriage Act
The Civil Marriage Act (full title: An Act respecting certain aspects of legal capacity for marriage for civil purposes) (the Act) was legislation legalizing same-sex marriage across Canada. At the time the bill became law, same-sex marriage had already been legalized by court decisions in all Canadian provinces except Alberta and Prince Edward Island, as well as in the territories of Nunavut and the Northwest Territories. It was introduced as Bill C-38 in the first session of the 38th Parliament of Canada on February 1, 2005. It passed the House of Commons on June 28, 2005, and the Senate on July 19, 2005. The Act became law when it received Royal Assent on July 20, 2005. As with all federal legislation in Canada, the Act is written in both French and English, with equal force. The French title is Loi sur le mariage civil, or in full, Loi concernant certaines conditions de fond du mariage civil.
  • 3.1K
  • 04 Nov 2022
Topic Review
Water Ionizer
A water ionizer (also known as an alkaline ionizer) is a home appliance which claims to raise the pH of drinking water by using electrolysis to separate the incoming water stream into acidic and alkaline components. The alkaline stream of the treated water is called alkaline water. Proponents claim that consumption of alkaline water results in a variety of health benefits, making it similar to the alternative health practice of alkaline diets. Such claims violate basic principles of chemistry and physiology. There is no medical evidence for any health benefits of alkaline water. Extensive scientific evidence has completely debunked these claims. The machines originally became popular in Japan and other East Asian countries before becoming available in the United States and Europe.
  • 3.1K
  • 07 Nov 2022
Topic Review
Miscanthus X Giganteus
Miscanthus × giganteus, also known as the giant miscanthus, is a sterile hybrid of Miscanthus sinensis and Miscanthus sacchariflorus. It is a perennial grass with bamboo-like stems that can grow to heights of 3–4 metres (13 ft) in one season (from the third season onwards). Just like Pennisetum purpureum, Arundo donax and Saccharum ravennae, it is also called elephant grass. Miscanthus × giganteus' perennial nature, its ability to grow on marginal land, its water efficiency, non-invasiveness, low fertilizer needs, significant carbon sequestration and high yield have sparked significant interest among researchers, with some arguing that it has "ideal" energy crop properties. Some argue that it can provide negative emissions, while others highlight its water cleaning and soil enhancing qualities. There are practical and economic challenges related to its use in the existing, fossil based combustion infrastructure, however. Torrefaction and other fuel upgrading techniques are being explored as countermeasures to this problem.
  • 3.1K
  • 01 Dec 2022
Biography
David Abram
David Abram (born June 24, 1957) is an American philosopher, cultural ecologist, and performance artist, best known for his work bridging the philosophical tradition of phenomenology with environmental and ecological issues.[1][2] He is the author of Becoming Animal: An Earthly Cosmology[3] (2010) and The Spell of the Sensuous: Perception and Language in a More-than-Human World (1996), for which
  • 3.1K
  • 12 Dec 2022
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