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Topic Review
NASDAQ-100
The NASDAQ-100 (^NDX) is a stock market index made up of 103 equity securities issued by 100 of the largest non-financial companies listed on the Nasdaq stock market. It is a modified capitalization-weighted index. The stocks' weights in the index are based on their market capitalizations, with certain rules capping the influence of the largest components. It is based on exchange, and it does not have any financial companies. The financial companies were put in a separate index, the NASDAQ Financial-100.
  • 7.1K
  • 19 Oct 2022
Topic Review
Embryology of Aorta
The aorta is the largest elastic artery in the human body and is classically divided into two anatomical segments, the thoracic and the abdominal aorta, separated by the diaphragm. The thoracic aorta includes the aortic root, the ascending aorta, the arch, and the descending aorta. The aorta’s elastic properties depend on its wall structure, composed of three distinct histologic layers: intima, media, and adventitia. The different aortic segments show different embryological and anatomical features, which account for their different physiological properties and impact the occurrence and natural history of congenital and acquired diseases that develop herein.
  • 7.1K
  • 30 Jun 2023
Topic Review
Geodetic Datum
A geodetic datum or geodetic system (also: geodetic reference datum or geodetic reference system) is a coordinate system, and a set of reference points, used for locating places on the Earth (or similar objects). An approximate definition of sea level is the datum WGS 84, an ellipsoid, whereas a more accurate definition is Earth Gravitational Model 2008 (EGM2008), using at least 2,159 spherical harmonics. Other datums are defined for other areas or at other times; ED50 was defined in 1950 over Europe and differs from WGS 84 by a few hundred meters depending on where in Europe you look. Mars has no oceans and so no sea level, but at least two martian datums have been used to locate places there. Datums are used in geodesy, navigation, and surveying by cartographers and satellite navigation systems to translate positions indicated on maps (paper or digital) to their real position on Earth. Each starts with an ellipsoid (stretched sphere), and then defines latitude, longitude and altitude coordinates. One or more locations on the Earth's surface are chosen as anchor "base-points". The difference in co-ordinates between datums is commonly referred to as datum shift. The datum shift between two particular datums can vary from one place to another within one country or region, and can be anything from zero to hundreds of meters (or several kilometers for some remote islands). The North Pole, South Pole and Equator will be in different positions on different datums, so True North will be slightly different. Different datums use different interpolations for the precise shape and size of the Earth (reference ellipsoids). Because the Earth is an imperfect ellipsoid, localised datums can give a more accurate representation of the area of coverage than WGS 84. OSGB36, for example, is a better approximation to the geoid covering the British Isles than the global WGS 84 ellipsoid. However, as the benefits of a global system outweigh the greater accuracy, the global WGS 84 datum is becoming increasingly adopted. Horizontal datums are used for describing a point on the Earth's surface, in latitude and longitude or another coordinate system. Vertical datums measure elevations or depths.
  • 7.1K
  • 24 Nov 2022
Topic Review
Relative Humidity
Relative humidity (RH) is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature. Relative humidity depends on temperature and the pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point.
  • 7.1K
  • 29 Sep 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
  • 7.1K
  • 14 Apr 2025
Topic Review
Polish Pension System
Polish’s Pension System was reformed in 1999. The new system is built from three parts. It comprises a public pension and an earnings-related system with notional accounts.  There are also voluntary employer sponsored pension plans.
  • 7.1K
  • 02 Nov 2020
Topic Review
Smart Grid Management, Control, and Operation
Smart grid management, control and operation (SGMCO) are key tasks for maintaining their proper functioning as well as for their extension and expansion. The current challenges of power generation, distribution, transmission, and consumption, as well as growing energy demand, facilitate the integration of a large number of smart grids with renewable energy generators and physical information systems, while smart grids are moving toward distribution and decentralization in response to the evolving application of the Internet of Energy (IoE). SGMCO handles not only traditional management, control, and operations, but also the future challenges for smart grids: Collaboration between stakeholders, control of network imbalances (e.g. frequency and voltage regulation), data analysis and management, decentralized network management and operation, and security and privacy.
  • 7.1K
  • 10 Jan 2022
Topic Review
Secretory IgA
Secretory IgA (SIgA) is the dominant antibody class in mucosal secretions, it is also present in saliva and breast milk. The majority of plasma cells producing SIgA are located within mucosal membranes lining the intestines, airway and reproductive tracts, as well as mammary gland. SIgA protects against the adhesion of pathogens and their penetration into the mucosal barriers. Moreover, SIgA regulates microbiota composition at mucosa sites and provides local homeostasis.
  • 7.1K
  • 17 Jan 2021
Topic Review
Liquid Hydrogen
Decarbonization plays an important role in future energy systems for reducing greenhouse gas emissions and establishing a zero-carbon society. Hydrogen is believed to be a promising secondary energy source (energy carrier) that can be converted, stored, and utilized efficiently, leading to a broad range of possibilities for future applications. 
  • 7.1K
  • 27 Sep 2021
Topic Review
Palm Oil Mill Effluent (POME)
Disposal of palm oil mill effluent (POME), which is highly polluting from the palm oil industry, needs to be handled properly to minimize the harmful impact on the surrounding environment.
  • 7.1K
  • 01 Nov 2021
Topic Review
Crosslinking Agent for on Cellulose-Based Hydrogels
Hydrogels are interlinked hydrophilic polymers that are insoluble in water but are capable of absorbing large amounts of water through the swelling process. During the swelling process, the polar groups in the polymer chain swiftly draw the first water molecules into the hydrogel network (bound water). The hydrogel network absorbs more water molecules due to the osmotic pressure of the interstitial water and free water. Both synthetic and natural polymers can be used to create hydrogels. Natural polymer-based hydrogels are typically chosen because of their excellent biocompatibility and biodegradability. In addition, natural polymers are less expensive than synthetic ones.  A crosslinking agent is used to strengthen the properties of the hydrogel. A chemical crosslinking agent is used more often than a physical crosslinking agent. In a chemical crosslinking agent, there are two types of crosslinking agents, which is synthetic and natural crosslinking agents. Hydrogels that utilize synthetic crosslinking agents have advantages, such as adjustable mechanical properties and easy control of the chemical composition. However, hydrogels that use natural crosslinking agents have better biocompatibility and less latent toxic effect.
  • 7.1K
  • 28 Sep 2022
Biography
Pierre-Joseph Proudhon
Pierre-Joseph Proudhon (/ˈpruːdɒn/;[1] French: [pjɛʁʒozɛf pʁudɔ̃]; 15 January 1809 – 19 January 1865) was a French politician, philosopher and the founder of mutualist philosophy. He was the first person to declare himself an anarchist,[2][3] using that term, and is widely regarded as one of the ideology's most influential theorists. Proudhon is even considered by many to be the "fa
  • 7.1K
  • 15 Nov 2022
Topic Review
Taxonomy
In biology, taxonomy (from grc τάξις (taxis) 'arrangement', and -νομία (-nomia) 'method') is the scientific study of naming, defining (circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a more inclusive group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum (division is sometimes used in botany in place of phylum), class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, as he developed a ranked system known as Linnaean taxonomy for categorizing organisms and binomial nomenclature for naming organisms. With advances in the theory, data and analytical technology of biological systematics, the Linnaean system has transformed into a system of modern biological classification intended to reflect the evolutionary relationships among organisms, both living and extinct.
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  • 05 Dec 2022
Topic Review
May 20: Vasco da Gama Reaches India
Vasco da Gama’s arrival in Calicut, India on May 20, 1498, marked the first time a European reached India by sea, successfully navigating around the Cape of Good Hope and across the Indian Ocean. This event opened a direct maritime trade route between Europe and Asia, breaking the centuries-old overland monopoly held by Middle Eastern and Venetian traders. It initiated an era of European exploration, imperial expansion, and global maritime dominance, especially for Portugal.
  • 7.1K
  • 20 May 2025
Topic Review
Sensor-Based Solid Waste Handling Systems
As a consequence of swiftly growing populations in the urban areas, larger quantities of solid waste also form rapidly. Since urban local bodies are found to be unable to manage this perilous situation effectively, there is a high probability of risks relative to the environment and public health. A sudden change is indispensable in the existing systems that are developed for the collection, transportation, and disposal of solid waste, which are entangled in turmoil. However, Smart sensors and wireless technology enable cyber-physical systems to automate solid waste management, which will revolutionize the industry. 
  • 7.1K
  • 01 Apr 2022
Topic Review
Cationic Surfactants
Cationic surfactants are a class of surfactant molecules that contain a positively charged head group and a long hydrophobic tail. They have a wide range of properties that make them useful in various applications, including solubility in water and organic solvents, high surface activity, emulsification, antimicrobial activity, conditioning properties, and fabric softening. However, some cationic surfactants can be toxic to aquatic life, so they should be used with caution in applications where they may come into contact with the environment. Overall, cationic surfactants are important molecules that play a crucial role in various industrial, personal care, and household applications. Cationic surfactants are a type of surfactant that have a positively charged hydrophilic (water-loving) head and a hydrophobic (water-hating) tail. The positive charge on the head of the surfactant makes it attracted to negatively charged surfaces, such as cell membranes and proteins. Due to their positive charge, cationic surfactants are often used in personal care and household cleaning products, as well as in the textile and paper industries. They are effective in removing dirt, oil, and other contaminants from surfaces, as they can bind to these substances and help to lift them away from the surface. Cationic surfactants can also have antimicrobial properties, as they can disrupt the cell membranes of bacteria and other microorganisms. This makes them useful in disinfectants, as well as in personal care products such as shampoos and body washes.
  • 7.0K
  • 24 Mar 2023
Topic Review
Hybrid
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes. A few animal species and many plant species, however, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled. Human impact on the environment has resulted in an increase in the interbreeding between regional species, and the proliferation of introduced species worldwide has also resulted in an increase in hybridisation. This genetic mixing may threaten many species with extinction, while genetic erosion from monoculture in crop plants may be damaging the gene pools of many species for future breeding. A form of often intentional human-mediated hybridisation is the crossing of wild and domesticated species. This is common in both traditional horticulture and modern agriculture; many commercially useful fruits, flowers, garden herbs, and trees have been produced by hybridisation. One such flower, Oenothera lamarckiana, was central to early genetics research into mutationism and polyploidy. It is also more occasionally done in the livestock and pet trades; some well-known wild × domestic hybrids are beefalo and wolfdogs. Human selective breeding of domesticated animals and plants has resulted in the development of distinct breeds (usually called cultivars in reference to plants); crossbreeds between them (without any wild stock) are sometimes also imprecisely referred to as "hybrids". Hybrid humans existed in prehistory. For example, Neanderthals and anatomically modern humans are thought to have interbred as recently as 40,000 years ago. Mythological hybrids appear in human culture in forms as diverse as the Minotaur, blends of animals, humans and mythical beasts such as centaurs and sphinxes, and the Nephilim of the Biblical apocrypha described as the wicked sons of fallen angels and attractive women.
  • 7.0K
  • 24 Nov 2022
Topic Review
Soaps and Syndets in Skin Cleansing
Skin cleansers generally come in one of two types: soap-based and synthetic detergents, or syndets. While the latter can effectively maintain the native skin structure, function and integrity, the former tends to negatively affect the skin by causing barrier disruption, lipid dissolution and pH alteration. Despite this, soap is still often preferred, possibly due to the negative connotations around anything that is not perceived as ‘natural’. 
  • 7.0K
  • 21 Apr 2022
Topic Review
Additive Manufacturing of Turbine Blades
Additive manufacturing is a technology of transforming a 3D prototype to a physical one directly by successive addition of the required material in a layer-by-layer manner. This technique helps to manufacture the turbine blade which is the revolution of green technology for high temperature engine parts.
  • 7.0K
  • 11 Oct 2022
Topic Review
University Social Responsibility
University Social Responsibility (USR) enhances educational development and the impact of universities on society. As a stakeholder in USR, it is imperative to develop a comprehensive literacy scale that reflects the development of students’ citizenship in social engagement.
  • 7.0K
  • 26 Apr 2022
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