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Topic Review

The "Vimana" is one such concept in ancient Indian texts that has been in the spotlight of most scholars, historians, and enthusiasts of ancient technology. Indeed, Vimanas, as they are described in Hindu epics or Vedic literature, flying machines or celestial chariots have amazed many a knowledgeable intellect, and some even go to the extent of citing them as evidence for advanced knowledge in aeronautical science in ancient India.

7.6K
31 Oct 2024

Topic Review

Spray Congealing Technology

Spray congealing is an emerging technology for the production of solid dispersion to enhance the bioavailability of poorly soluble drugs by using low-melting hydrophilic excipients. Since the '90s, spray congealing technology has been used to obtain microparticles (MPs) for controlled release, taste masking and stability enhancement of APIs. The main advantages are the absence of solvents and the possibility to obtain free-flowing MPs by a relatively inexpensive, simple and one step process. This entry focused on the application of spary congealing as an amerging technology for the production of solid dispersions to enhance the bioavailability of poorly water soluble drugs by using low-melting hydrophilic excipients.

7.6K
14 Dec 2021

Topic Review

Short-Chain Fatty Acids

The relationship between diet and the diversity and function of the intestinal microbiome and its importance for human health is currently the subject of many studies. The type and proportion of microorganisms found in the intestines can determine the energy balance of the host. Intestinal microorganisms perform many important functions, one of which is participation in metabolic processes, e.g., in the production of short-chain fatty acids—SCFAs (also called volatile fatty acids). These acids represent the main carbon flow from the diet to the host microbiome. Maintaining intestinal balance is necessary to maintain the host’s normal health and prevent many diseases. The results of many studies confirm the beneficial effect of probiotic microorganisms on the balance of the intestinal microbiome and produced metabolites, including SCFAs. The aim of this review is to summarize what is known on the effects of probiotics on the production of short-chain fatty acids by gut microbes. In addition, the mechanism of formation and properties of these metabolites is discussed and verified test results confirming the effectiveness of probiotics in human nutrition by modulating SCFAs production by intestinal microbiome is presented.

7.6K
30 Oct 2020

Topic Review

Pathogenic Bacteria

Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract. The body is continually exposed to many species of bacteria, including beneficial commensals, which grow on the skin and mucous membranes, and saprophytes, which grow mainly in the soil and in decaying matter. The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immunity or innate resistance against many microorganisms. Pathogenic bacteria are specially adapted and endowed with mechanisms for overcoming the normal body defences, and can invade parts of the body, such as the blood, where bacteria are not normally found. Some pathogens invade only the surface epithelium, skin or mucous membrane, but many travel more deeply, spreading through the tissues and disseminating by the lymphatic and blood streams. In some rare cases a pathogenic microbe can infect an entirely healthy person, but infection usually occurs only if the body's defence mechanisms are damaged by some local trauma or an underlying debilitating disease, such as wounding, intoxication, chilling, fatigue, and malnutrition. In many cases, it is important to differentiate infection and colonization, which is when the bacteria are causing little or no harm. Caused by Mycobacterium tuberculosis bacteria, one of the diseases with the highest disease burden is tuberculosis, which killed 1.4 million people in 2019, mostly in sub-Saharan Africa. Pathogenic bacteria contribute to other globally important diseases, such as pneumonia, which can be caused by bacteria such as Streptococcus, Pneumococcus and Pseudomonas, and foodborne illnesses, which can be caused by bacteria such as Shigella, Campylobacter, and Salmonella. Pathogenic bacteria also cause infections such as tetanus, typhoid fever, diphtheria, syphilis, and leprosy. Pathogenic bacteria are also the cause of high infant mortality rates in developing countries. Most pathogenic bacteria can be grown in cultures and identified by Gram stain and other methods. Bacteria grown in this way are often tested to find which antibiotics will be an effective treatment for the infection. For hitherto unknown pathogens, Koch's postulates are the standard to establish a causative relationship between a microbe and a disease.

7.6K
07 Nov 2022

Topic Review

In Hinduism and Jainism, aparigraha (Sanskrit: अपरिग्रह) is the virtue of non-possessiveness, non-grasping or non-greediness. Aparigrah is the opposite of parigrah, and refers to keeping the desire for possessions to what is necessary or important, depending on one's life stage and context. The precept of aparigraha is a self-restraint (temperance) from the type of greed and avarice where one's own material gain or happiness comes by hurting, killing or destroying other human beings, life forms or nature. Aparigraha is related to and in part a motivator of dāna (proper charity), both from giver's and receiver's perspective.

7.6K
13 Oct 2022

Topic Review

Glossary of Bird Terms

The following is a glossary of common English language terms used in the description of birds—warm-blooded vertebrates of the class Aves and the only living dinosaurs, characterized by feathers, the ability to fly in all but the approximately 60 extant species of flightless birds, toothless, beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart and a strong yet lightweight skeleton. Among other details such as size, proportions and shape, terms defining bird features developed and are used to describe features unique to the class—especially evolutionary adaptations that developed to aid flight. There are, for example, numerous terms describing the complex structural makeup of feathers (e.g., barbules, rachides and vanes); types of feathers (e.g., filoplume, pennaceous and plumulaceous feathers); and their growth and loss (e.g., colour morph, nuptial plumage and pterylosis). There are thousands of terms that are unique to the study of birds. This glossary makes no attempt to cover them all, concentrating on terms that might be found across descriptions of multiple bird species by bird enthusiasts and ornithologists. Though words that are not unique to birds are also covered, such as "back" or "belly", they are defined in relation to other unique features of external bird anatomy, sometimes called "topography". As a rule, this glossary does not contain individual entries on any of the approximately 9,700 recognized living individual bird species of the world.

7.6K
09 Nov 2022

Topic Review

High Frequency Active Auroral Research Program

The High Frequency Active Auroral Research Program (HAARP) was initiated as an ionospheric research program jointly funded by the United States Air Force , the U.S. Navy, the University of Alaska Fairbanks, and the Defense Advanced Research Projects Agency (DARPA). It was designed and built by BAE Advanced Technologies (BAEAT). Its original purpose was to analyze the ionosphere and investigate the potential for developing ionospheric enhancement technology for radio communications and surveillance. As a university-owned facility, HAARP is a high-power, high-frequency transmitter used for study of the ionosphere. The most prominent instrument at HAARP is the Ionospheric Research Instrument (IRI), a high-power radio frequency transmitter facility operating in the high frequency (HF) band. The IRI is used to temporarily excite a limited area of the ionosphere. Other instruments, such as a VHF and a UHF radar, a fluxgate magnetometer, a digisonde (an ionospheric sounding device), and an induction magnetometer, are used to study the physical processes that occur in the excited region. Work on the HAARP facility began in 1993. The current working IRI was completed in 2007; its prime contractor was BAE Systems Advanced Technologies. As of 2008, HAARP had incurred around $250 million in tax-funded construction and operating costs. In May 2014, it was announced that the HAARP program would be permanently shut down later in the year. After discussions between the parties, ownership of the facility and its equipment was transferred to the University of Alaska Fairbanks in August 2015. HAARP is a target of conspiracy theorists, who claim that it is capable of "weaponizing" weather. Commentators and scientists say that advocates of this theory are uninformed, as claims made fall well outside the abilities of the facility, if not the scope of natural science.

7.6K
21 Nov 2022

Topic Review

Areas of Mathematics

Mathematics encompasses a growing variety and depth of subjects over its history, and comprehension of it requires a system to categorize and organize these various subjects into more general areas of mathematics. A number of different classification schemes have arisen, and though they share some similarities, there are differences due in part to the different purposes they serve. A traditional division of mathematics is into pure mathematics; mathematics studied for its intrinsic interest, and applied mathematics; the mathematics that can be directly applied to real-world problems. This division is not always clear and many subjects have been developed as pure mathematics to find unexpected applications later on. Broad divisions, such as discrete mathematics, computational mathematics and so on have emerged more recently. An ideal system of classification permits adding new areas into the organization of previous knowledge, and fitting surprising discoveries and unexpected interactions into the outline. For example, the Langlands program has found unexpected connections between areas previously thought unconnected, at least Galois groups, Riemann surfaces and number theory.

7.6K
29 Sep 2022

Topic Review

List of Human Spaceflight Programs

This is a list of human spaceflight programs, including successful programs, programs that were canceled, and programs planned for the future. The criteria for what constitutes human spaceflight vary. The FAI defines spaceflight as any flight over 100 kilometers (62 mi). In the U.S. professional, military, and commercial astronauts who travel above an altitude of 80 kilometers (50 mi) are awarded astronaut wings. This article follows the FAI definition of spaceflight. Until the 21st century, human spaceflight programs were sponsored exclusively by governments, through either the military or civilian space agencies. With the launch of the privately funded SpaceShipOne in 2004, a new category of human spaceflight programs – commercial human spaceflight – arrived.

7.6K
09 Nov 2022

Topic Review

A wife is a female partner in a continuing marital relationship. The term continues to be applied to a woman who has separated from her partner, and ceases to be applied to such a woman only when her marriage has come to an end, following a legally recognized divorce or the death of her spouse. On the death of her partner, a wife is referred to as a widow, but not after she is divorced from her partner. The rights and obligations of a wife in relation to her partner and her status in the community and in law vary between cultures and have varied over time.

7.6K
17 Nov 2022

Topic Review

STEAMComp Edu: STEAM Competence Framework for Educators

STEAM (science, technology, engineering, arts, and mathematics) education is gaining increasing attention worldwide, with many initiatives being implemented to promote its adoption and effectiveness; thus, its successful integration into educational systems has become increasingly critical. Educators will play a central role in this integration; that is why it is critical to assess their needs, map the necessary roles and competences, and provide the means to guide their professional development in a systematic way. To address these requirements, our study introduces the STEAM Competence Framework for Educators (STEAMComp Edu), as a culmination of literature reviews, expert consultations, and empirical validation by 302 educational professionals, policymakers, and scholars.

7.6K
09 Nov 2024

Topic Review

Smart manufacturing, an advanced form of traditional manufacturing

Traditional manufacturing is an industrial process that converts materials into a finished product using a labor-intensive low-end operation, low precision, average resource utilization and efficiency for economic value.

7.6K
28 Mar 2022

Topic Review

The five precepts (Pali: pañcasīla; Sanskrit: pañcaśīla) or five rules of training (Pali: pañcasikkhapada; Sanskrit: pañcaśikṣapada) is the most important system of morality for Buddhist lay people. They constitute the basic code of ethics undertaken by lay followers of Buddhism. The precepts are commitments to abstain from killing living beings, stealing, sexual misconduct, lying and intoxication. Within the Buddhist doctrine, they are meant to develop mind and character to make progress on the path to enlightenment. They are sometimes referred to as the śrāvakayāna precepts in the Mahāyāna tradition, contrasting them with the bodhisattva precepts. The five precepts form the basis of several parts of Buddhist doctrine, both lay and monastic. With regard to their fundamental role in Buddhist ethics, they have been compared with the ten commandments in Christianity or the ethical codes of Confucianism. The precepts have been connected with utilitarianist, deontological and virtue approaches to ethics. They have been compared with human rights because of their universal nature, and some scholars argue they can complement the concept of human rights. The five precepts were common to the religious milieu of 6th-century BCE India, but the Buddha's focus on awareness through the fifth precept was unique. As shown in Early Buddhist Texts, the precepts grew to be more important, and finally became a condition for membership of the Buddhist religion. When Buddhism spread to different places and people, the role of the precepts began to vary. In countries where Buddhism had to compete with other religions, such as China, the ritual of undertaking the five precepts developed into an initiation ceremony to become a Buddhist lay person. On the other hand, in countries with little competition from other religions, such as Thailand, the ceremony has had little relation to the rite of becoming Buddhist, as many people are presumed Buddhist from birth. Undertaking and upholding the five precepts is based on the principle of non-harming (Pāli and Sanskrit: ahiṃsa). The Pali Canon recommends one to compare oneself with others, and on the basis of that, not to hurt others. Compassion and a belief in karmic retribution form the foundation of the precepts. Undertaking the five precepts is part of regular lay devotional practice, both at home and at the local temple. However, the extent to which people keep them differs per region and time. People keep them with an intention to develop themselves, but also out of fear of a bad rebirth. The first precept consists of a prohibition of killing, both humans and all animals. Scholars have interpreted Buddhist texts about the precepts as an opposition to and prohibition of capital punishment, suicide, abortion and euthanasia. In practice, however, many Buddhist countries still use the death penalty. With regard to abortion, Buddhist countries take the middle ground, by condemning though not prohibiting it. The Buddhist attitude to violence is generally interpreted as opposing all warfare, but some scholars have raised exceptions. The second precept prohibits theft. The third precept refers to adultery in all its forms, and has been defined by modern teachers with terms such as sexual responsibility and long-term commitment. The fourth precept involves falsehood spoken or committed to by action, as well as malicious speech, harsh speech and gossip. The fifth precept prohibits intoxication through alcohol, drugs or other means. Early Buddhist Texts nearly always condemn alcohol, and so do Chinese Buddhist post-canonical texts. Buddhist attitudes toward smoking differ per time and region, but are generally permissive. In modern times, traditional Buddhist countries have seen revival movements to promote the five precepts. As for the West, the precepts play a major role in Buddhist organizations. They have also been integrated in mindfulness training programs, though many mindfulness specialists do not support this because of the precepts' religious import. Lastly, many conflict prevention programs make use of the precepts.

7.6K
22 Nov 2022

Topic Review

ISO Standards for Trailer Connectors

A number of ISO standards cover trailer connectors, the electrical connectors between vehicles and the trailers they tow that provide a means of control for the trailers. These are listed below, with notes on significant deviations from them that can cause problems.

7.5K
07 Nov 2022

Topic Review

Artemisia vulgaris L. (common mugwort)

Artemisia vulgaris L. (common mugwort) is a species with great importance in the history of medicine and was called the “mother of herbs” in the Middle Ages. It is a common herbaceous plant that exhibits high morphological and phytochemical variability depending on the location it occurs. This species is well known almost all over the world. Its herb—Artemisiae vulgaris herba—is used as a raw material due to the presence of volatile oil, flavonoids, and sesquiterpene lactones and their associated biological activities. The European Pharmacopoeia has listed this species as a potential homeopathic raw material. Moreover, this species has been used in traditional Chinese, Hindu, and European medicine to regulate the functioning of the gastrointestinal system and treat various gynecological diseases. The general aim of this review was to analyze the progress of phytochemical and pharmacological as well as professional scientific studies focusing on A. vulgaris. Thus far, numerous authors have confirmed the beneficial properties of A. vulgaris herb extracts, including their antioxidant, hepatoprotective, antispasmolytic, antinociceptive, estrogenic, cytotoxic, antibacterial, and antifungal effects. In addition, several works have reviewed the use of this species in the production of cosmetics and its role as a valuable spice in the food industry.

7.5K
05 Nov 2020

Topic Review

Accretion (Astrophysics)

In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.

7.5K
11 Nov 2022

Topic Review

The development of engineered silica particles by using low-cost renewable or waste resources is a key example of sustainability. Rice husks have emerged as a renewable resource for the production of engineered silica particles as well as bioenergy.

7.5K
17 Jan 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.

7.5K
20 May 2025

Topic Review

Reindeer Distribution

The reindeer is a widespread and numerous species in the northern Holarctic, being present in both tundra and taiga (boreal forest). Originally, the reindeer was found in Scandinavia, eastern Europe, Russia , Mongolia, and northern China north of the 50th latitude. In North America, it was found in Canada , Alaska (United States ), and the northern contiguous USA from Washington to Maine. In the 19th century, it was apparently still present in southern Idaho. It also occurred naturally on Sakhalin, Greenland, and probably even in historical times in Ireland. During the late Pleistocene era, reindeer were found further south, such as at Nevada, Tennessee , and Alabama in North America and Spain in Europe. Today, wild reindeer have disappeared from many areas within this large historical range, especially from the southern parts, where it vanished almost everywhere. Populations of wild reindeer are still found in Norway , Finland , Siberia, Greenland, Alaska, and Canada . Domesticated reindeer are mostly found in northern Fennoscandia and Russia, with a herd of approximately 150–170 semi-domesticated reindeer living around the Cairngorms region in Scotland. The last remaining wild tundra reindeer in Europe are found in portions of southern Norway . A few reindeer from Norway were introduced to the South Atlantic island of South Georgia in the beginning of the 20th century. The South Georgian reindeer totaled some estimated 2600 animals in two distinct herds separated by glaciers. Although the flag and the coat of arms of the territory contain an image of a reindeer, they were eradicated from 2013 to 2017 because of the environmental damage they caused. Around 4000 reindeer have been introduced into the French sub-Antarctic archipelago of Kerguelen Islands. East Iceland has a small herd of about 2500–3000 animals. Caribou and reindeer numbers have fluctuated historically, but many herds are in decline across their range. This global decline is linked to climate change for northern, migratory caribou and reindeer herds and industrial disturbance of caribou habitat for sedentary, non-migratory herds.

7.5K
28 Nov 2022

Topic Review

Product Distribution

A product distribution is a probability distribution constructed as the distribution of the product of random variables having two other known distributions. Given two statistically independent random variables X and Y, the distribution of the random variable Z that is formed as the product is a product distribution.

7.5K
11 Nov 2022

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