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Topic Review

In sociology, a group is a social entity composed of two or more individuals who interact with one another, share a sense of identity, and are bound by a common purpose or goal. These social groups can range from intimate and small-scale, such as families, to larger and more complex structures like organizations or communities. The study of groups in sociology provides insights into human social behavior, dynamics, and the influence of collective processes on individuals within the societal framework.

9.0K
25 Jan 2024

Topic Review

Zipline (Drone Delivery)

Zipline is an American medical product delivery company that is headquartered in South San Francisco, California, and which designs, manufactures, and operates delivery drones. The company operates distribution centers in Rwanda, Ghana, and the US, with signed agreements to begin service in Japan , Nigeria, Cote d'Ivoire, and Kenya. As of December 2021, its drones have made over 225,000 commercial deliveries. The company's drones deliver whole blood, platelets, frozen plasma, and cryoprecipitate along with medical products including vaccines, infusions and routine medical commodities. As of September 2021, more than 75% of blood deliveries in Rwanda outside of Kigali use Zipline drones. In April 2019 in Ghana, the company began using drones to deliver vaccines, blood, and medicines. During the COVID-19 pandemic in 2020, the US Federal Aviation Administration (FAA) granted a Part 107 waiver to Zipline's partner organization Novant Health for the delivery of medical supplies and personal protective equipment (PPE) to medical facilities in North Carolina. Along with nine other drone delivery companies, the FAA selected Zipline to participate in a type certification program for delivery drones.

9.0K
06 Oct 2022

Topic Review

Chinese Polearms

The three most common types of Chinese polearms are the ge (戈), qiang (槍), and ji (戟). They are translated into English as dagger-axe, spear, and halberd. Dagger-axes were originally a short slashing weapon with a 0.9 to 1.8 m long shaft, but around the 4th century BC a spearhead was added to the blade, and it became a halberd. The spear is also sometimes called a mao (矛), which is sometimes used to designate polearms with a wavy snake-like spearhead. There was another polearm weapon known as the pi (鈹), translated into English as either sword-staff or long lance, that was used from ancient times until the Han dynasty. It was essentially a short sword attached to a stick. From the Warring States period onward, the length of Chinese polearms varied from around 2.8 m to 5.5 m, however there is no specific designation for a pike in the traditional Chinese lexicon. A very long spear is just called a long spear.

8.9K
13 Oct 2022

Topic Review

Nature has two inter-related meanings in philosophy and natural philosophy. On the one hand, it means the set of all things which are natural, or subject to the normal working of the laws of nature. On the other hand, it means the essential properties and causes of individual things. How to understand the meaning and significance of nature has been a consistent theme of discussion within the history of Western Civilization, in the philosophical fields of metaphysics and epistemology, as well as in theology and science. The study of natural things and the regular laws which seem to govern them, as opposed to discussion about what it means to be natural, is the area of natural science. The word "nature" derives from Latin nātūra, a philosophical term derived from the verb for birth, which was used as a translation for the earlier (pre-Socratic) Greek term phusis, derived from the verb for natural growth. Already in classical times, philosophical use of these words combined two related meanings which have in common that they refer to the way in which things happen by themselves, "naturally", without "interference" from human deliberation, divine intervention, or anything outside what is considered normal for the natural things being considered. Understandings of nature depend on the subject and age of the work where they appear. For example, Aristotle's explanation of natural properties differs from what is meant by natural properties in modern philosophical and scientific works, which can also differ from other scientific and conventional usage. Stoicism encourages practitioners to live in accordance with nature. Pyrrhonism encourages practitioners to use the guidance of nature in decision making.

8.9K
09 Oct 2022

Topic Review

Deep Eutectic Solvents (DES)

Deep eutectic solvent (DES) are a highly non-ideal mixture of two biodegradable components (HBA and HBD) associated with strong hydrogen bonding interactions.

8.9K
08 Mar 2022

Topic Review

Refractive Index and Extinction Coefficient of Thin-Film Materials

The derivation of the Forouhi–Bloomer dispersion equations is based on obtaining an expression for k as a function of photon energy, symbolically written as k(E), starting from first principles quantum mechanics and solid state physics. An expression for n as a function of photon energy, symbolically written as n(E), is then determined from the expression for k(E) in accordance to the Kramers–Kronig relations which states that n(E) is the Hilbert Transform of k(E). The Forouhi–Bloomer dispersion equations for n(E) and k(E) of amorphous materials are given as: [math]\displaystyle{ k(E) = \frac{A(E-E_g)^2}{E^2-BE+C} \ }[/math] [math]\displaystyle{ n(E) = n(\infty)+\frac{(B_0 E + C_0 )}{E^2-BE+C} \ }[/math] The five parameters A, B, C, Eg, and n(∞) each have physical significance. Eg is the optical energy band gap of the material. A, B, and C depend on the band structure of the material. They are positive constants such that 4C-B2 > 0. Finally, n(∞), a constant greater than unity, represents the value of n at E = ∞. The parameters B0 and C0 in the equation for n(E) are not independent parameters, but depend on A, B, C, and Eg. They are given by: [math]\displaystyle{ B_0 = \frac{A}{Q} \ \left (\frac{-B^2}{2} \ + E_gB - {E_g}^2 + C \right) }[/math] [math]\displaystyle{ C_0 = \frac{A}{Q} \ \left [({E_g}^2 + C) \frac{B}{2} \ - 2E_g C \right] }[/math] where [math]\displaystyle{ Q = \frac{1}{2} \ (4C - B^2 )^{\frac{1}{2}} }[/math] Thus, for amorphous materials, a total of five parameters are sufficient to fully describe the dependence of both n and k on photon energy, E. For crystalline materials which have multiple peaks in their n and k spectra, the Forouhi–Bloomer dispersion equations can be extended as follows: [math]\displaystyle{ k(E) = \sum_{i=1}^q \left [\frac{A_i(E - E_{g_i})^2}{E^2-B_iE+C_i} \right] }[/math] [math]\displaystyle{ n(E) = n(\infty)+\sum_{i=1}^q \left [\frac{B_{0_i}E+C_{0_i}}{E^2-B_iE+C_i} \right] }[/math] The number of terms in each sum, q, is equal to the number of peaks in the n and k spectra of the material. Every term in the sum has its own values of the parameters A, B, C, Eg, as well as its own values of B0 and C0. Analogous to the amorphous case, the terms all have physical significance.

8.9K
31 Oct 2022

Topic Review

Remarriage is a marriage that takes place after a previous marital union has ended, as through divorce or widowhood. Some individuals are more likely to remarry than others; the likelihood can differ based on previous relationship status (e.g. divorced vs. widowed), level of interest in establishing a new romantic relationship, gender, race, and age among other factors. Those who choose not to remarry may prefer alternative arrangements like cohabitation or living apart together. Remarriage also provides mental and physical health benefits. However, although remarried individuals tend to have better health than individuals who do not repartner, they still generally have worse health than individuals who have remained continuously married. Someone who repeatedly remarries is referred to as a serial wedder.

8.9K
27 Oct 2022

Topic Review

Androcentrism is a cultural and societal phenomenon characterized by the prioritization of male perspectives, experiences, and values over those of women. It manifests in various aspects of society, including language, media representation, and institutional practices, perpetuating gender inequalities and reinforcing patriarchal power structures.

8.9K
08 Feb 2024

Topic Review

Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People who report a lifelong history of such experiences are known as synesthetes. Awareness of synesthetic perceptions varies from person to person. In one common form of synesthesia, known as grapheme–color synesthesia or color–graphemic synesthesia, letters or numbers are perceived as inherently colored. In spatial-sequence, or number form synesthesia, numbers, months of the year, or days of the week elicit precise locations in space (e.g., 1980 may be "farther away" than 1990), or may appear as a three-dimensional map (clockwise or counterclockwise). Synesthetic associations can occur in any combination and any number of senses or cognitive pathways. Little is known about how synesthesia develops. It has been suggested that synesthesia develops during childhood when children are intensively engaged with abstract concepts for the first time. This hypothesis – referred to as semantic vacuum hypothesis – could explain why the most common forms of synesthesia are grapheme–color, spatial sequence, and number form. These are usually the first abstract concepts that educational systems require children to learn. Difficulties have been recognized in adequately defining synesthesia. Many different phenomena have been included in the term synesthesia, and in many cases the terminology seems to be inaccurate. A more accurate but less common term may be ideasthesia. The earliest recorded case of synesthesia is attributed to the Oxford University academic and philosopher John Locke, who, in 1690, made a report about a blind man who said he experienced the color scarlet when he heard the sound of a trumpet. However, there is disagreement as to whether Locke described an actual instance of synesthesia or was using a metaphor. The first medical account came from German physician Georg Tobias Ludwig Sachs in 1812. The term is from the Ancient Greek σύν syn, 'together', and αἴσθησις aisthēsis, 'sensation'.

8.9K
15 Nov 2022

Topic Review

The Effect of Parental Styles on Social Skills

Parental educational styles have a significant effect in personal development. These styles (authoritative, democratic, permissive and neglectful) can be related to affects and social skills at the individual level. The results suggest that parenting styles are closely related to affects and social skills. It is also suggested that affects play a mediating role in the relationship between parenting styles and social skills.

8.9K
23 Mar 2022

Topic Review Peer Reviewed

Challenges for Nanotechnology

The term “Nanotechnology” describes a large field of scientific and technical activities dealing with objects and technical components with small dimensions. Typically, bodies that are in–at least–two dimensions smaller than 0.1 µm are regarded as “nanobjects”. By this definition, a lot of advanced materials, as well as the advanced electronic devices, are objects of nanotechnology. In addition, many aspects of molecular biotechnology as well as macromolecular and supermolecular chemistry and nanoparticle techniques are summarized under “nanotechnology”. Despite this size-oriented definition, nanotechnology is dealing with physics and chemistry as well as with the realization of technical functions in the area between very small bodies and single particles and molecules. This includes the shift from classical physics into the quantum world of small molecules and low numbers or single elementary particles. Besides the already established fields of nanotechnology, there is a big expectation about technical progress and solution to essential economic, medical, and ecological problems by means of nanotechnology. Nanotechnology can only meet these expectations if fundamental progress behind the recent state of the art can be achieved. Therefore, very important challenges for nanotechnology are discussed here.

8.9K
13 Apr 2022

Topic Review

Atomic units (au or a.u.) form a system of natural units which is especially convenient for atomic physics calculations. There are two different kinds of atomic units, Hartree atomic units and Rydberg atomic units, which differ in the choice of the unit of mass and charge. This article deals with Hartree atomic units, where the numerical values of the following four fundamental physical constants are all unity by definition: In Hartree units, the speed of light is approximately [math]\displaystyle{ 137 }[/math]. Atomic units are often abbreviated "a.u." or "au", not to be confused with the same abbreviation used also for astronomical units, arbitrary units, and absorbance units in different contexts.

8.9K
10 Nov 2022

Topic Review

Acid throwing, also called an acid attack, a vitriol attack or vitriolage, is a form of violent assault defined as the act of throwing acid or a similarly corrosive substance onto the body of another "with the intention to disfigure, maim, torture, or kill". Perpetrators of these attacks throw corrosive liquids at their victims, usually at their faces, burning them, and damaging skin tissue, often exposing and sometimes dissolving the bones. The most common types of acid used in these attacks are sulfuric and nitric acid. Hydrochloric acid is sometimes used, but is much less damaging. Aqueous solutions of strongly alkaline materials, such as caustic soda (sodium hydroxide), are used as well, particularly in areas where strong acids are controlled substances. The long term consequences of these attacks may include blindness, as well as permanent scarring of the face and body, along with far-reaching social, psychological, and economic difficulties. Today, acid attacks are reported in many parts of the world. Since the 1990s, Bangladesh has been reporting the highest number of attacks and highest incidence rates for women, with 3,512 Bangladeshi people acid attacked between 1999 and 2013, and in Pakistan and India acid attacks are at an all-time high and increasing every year. Although acid attacks occur all over the world, this type of violence is most common in South Asia. The UK has one of the highest rates of acid attacks per capita in the world, according to Acid Survivors Trust International (ASTI). In 2016 there were over 601 acid attacks in the UK based on ASTI figures. Over 1,200 cases were recorded over the past 5 years. From 2011 to 2016 there were 1,464 crimes involving acid or corrosive substance in London alone.

8.9K
21 Oct 2022

Topic Review

Applications of Heterocyclic Compounds

Fluorescently labelled heterocyclic compounds are useful in bioanalytical applications, including in vivo imaging, high throughput screening, diagnostics, and light-emitting diodes. These compounds have various therapeutic properties, including antifungal, antitumor, antimalarial, anti-inflammatory, and analgesic activities. Different neutral fluorescent markers containing nitrogen heterocycles (quinolones, azafluoranthenes, pyrazoloquinolines, etc.) have several electrochemical, biological, and nonlinear optic applications. Photodynamic therapy (PDT), which destroys tumors and keeps normal tissues safe, works in the presence of molecular oxygen with light and a photosensitizing drugs (dye) to obtain a therapeutic effect.

8.9K
18 Oct 2022

Topic Review

Trickle-Down Economics

Trickle-down economics, also called trickle-down theory, refers to the economic proposition that taxes on businesses and the wealthy in society should be reduced as a means to stimulate business investment in the short term and benefit society at large in the long term. In recent history, the term has been used by critics of supply-side economic policies, such as "Reaganomics". Whereas general supply-side theory favors lowering taxes overall, trickle-down theory more specifically targets taxes on the upper end of the economic spectrum. The term "trickle-down" originated as a joke by humorist Will Rogers and today is often used to criticize economic policies that favor the wealthy or privileged while being framed as good for the average citizen. David Stockman, who as Ronald Reagan's budget director championed Reagan's tax cuts at first, later became critical of them and told journalist William Greider that "supply-side economics" is the trickle-down idea: Political opponents of the Reagan administration soon seized on this language in an effort to brand the administration as caring only about the wealthy. Some studies suggest a link between trickle-down economics and reduced growth. Trickle-down economics has been widely criticized, particularly by left-wing, centre-left and moderate politicians and economists, but also some right-wing politicians. A 2019 study in the Journal of Political Economy found, contrary to trickle-down theory, that "the positive relationship between tax cuts and employment growth is largely driven by tax cuts for lower-income groups and that the effect of tax cuts for the top 10 percent on employment growth is small."

8.9K
02 Dec 2022

Topic Review

Prime Video, also marketed as Amazon Prime Video, is an American Internet video on demand service that is developed, owned, and operated by Amazon. It offers television shows and films for rent or purchase and Prime Video, a selection of Amazon Studios original content and licensed acquisitions included in the Amazon's Prime subscription. In the United Kingdom , United States , Germany , and many other territories, access to Prime Video is also available through a video-only membership, which does not require a full Prime subscription. In France and Italy, and other countries like Australia , Canada , India , etc. Prime Video content is only accessible through a dedicated Prime Video website. In some countries Prime Video additionally offers Amazon Channels, which allows viewers to subscribe to other suppliers' content, including HBO in the United States. Launched on September 7, 2006 as Amazon Unbox in the United States, the service grew with its expanding library, and added the Prime Video membership with the development of Prime. It was then renamed as Amazon Instant Video on Demand. After acquiring the local streaming and DVD-by-mail service LoveFilm in 2011, Prime Video was added to Prime in the United Kingdom, Germany and Austria in 2014, a move that angered some Prime UK members as the bundling was non-negotiable with a 61% increase in subscription fee. In the UK, Germany, and Austria, Prime Video has been available on a monthly subscription of £5.99 or €7.99 per month, continuing the plan of LoveFilm Instant. The service was previously available in Norway , Denmark and Sweden in 2012, but was discontinued in 2013. On April 18, 2016, Amazon split Prime Video from Amazon Prime in the US for $8.99 per month. The service also hosts Amazon Original content alongside titles on Video as well. On December 14, 2016, Prime Video launched worldwide (except for Mainland China, Cuba, Iran, North Korea, Syria) expanding its reach beyond the US, the UK, Germany, Austria, and Japan. Among the new territories, the service was included with Prime in Belgium, Canada , France , India , Italy, Spain , Poland , and Brazil , while for all other countries – for instance Bulgaria – it was made available for a monthly promotional price of $/€2.99 per month for the first six months and $/€5.99 per month thereafter.

8.9K
29 Nov 2022

Topic Review

Religious Studies

Religious studies, alternately known as the study of religion, is an academic field devoted to research into religious beliefs, behaviors, and institutions. It describes, compares, interprets, and explains religion, emphasizing systematic, historically based, and cross-cultural perspectives. While theology attempts to understand the nature of transcendent or supernatural forces (such as deities), religious studies tries to study religious behavior and belief from outside any particular religious viewpoint. Religious studies draws upon multiple disciplines and their methodologies including anthropology, sociology, psychology, philosophy, and history of religion. Religious studies originated in the 19th century, when scholarly and historical analysis of the Bible had flourished, and Hindu and Buddhist texts were first being translated into European languages. Early influential scholars included Friedrich Max Müller, in England, and Cornelius P. Tiele, in the Netherlands. Today religious studies is practiced by scholars worldwide. In its early years, it was known as Comparative Religion or the Science of Religion and, in the USA, there are those who today also know the field as the History of religion (associated with methodological traditions traced to the University of Chicago in general, and in particular Mircea Eliade, from the late 1950s through to the late 1980s). The term "religion" originated from the Latin noun "religio", that was nominalized from one of three verbs: "relegere" (to turn to constantly/observe conscientiously); "religare" (to bind oneself [back]); and "reeligere" (to choose again). Because of these three different potential meanings, an etymological analysis alone does not resolve the ambiguity of defining religion, since each verb points to a different understanding of what religion is. During the Medieval Period, the term "religious" was used as a noun to describe someone who had joined a monastic order (a "religious"). The religious studies scholar Walter Capps described the purpose of the discipline as to provide "training and practice... in directing and conducting inquiry regarding the subject of religion". At the same time, Capps stated that its other purpose was to use "prescribed modes and techniques of inquiry to make the subject of religion intelligible." Religious studies scholar Robert A. Segal characterised the discipline as "a subject matter" that is "open to many approaches", and thus it "does not require either a distinctive method or a distinctive explanation to be worthy of disciplinary status." Different scholars operating in the field have different interests and intentions; some for instance seek to defend religion, while others seek to explain it away, and others wish to use religion as an example with which to prove a theory of their own. Some scholars of religious studies are interested in primarily studying the religion to which they belong. Scholars of religion have argued that a study of the subject is useful for individuals because it will provide them with knowledge that is pertinent in inter-personal and professional contexts within an increasingly globalised world. It has also been argued that studying religion is useful in appreciating and understanding sectarian tensions and religious violence.

8.9K
22 Nov 2022

Topic Review

History, Preparation, Characterization and Applications of Moisturizers

Moisturizers are one of the most widely used preparations in cosmetics and have been extensively used to soften the skin for consumers. Cosmetically, moisturizers make the skin smooth by the mechanism of increasing the water content in the stratum corneum, hence exerting its most vital action, which is moisturizing action and maintaining a normal skin pH.

8.9K
13 Jul 2022

Topic Review

The Nag missile (IAST: Nāga; en: Cobra), also called "Prospina" for the land-attack version, is an India n third-generation, all-weather, fire-and-forget, lock-on after launch, anti-tank guided missile (ATGM) with an operational range of 500 m to 20 km. It has a single-shot hit probability of 90% and a ten-year, maintenance-free shelf life. The Nag has five variants under development: a land version, for a mast-mounted system; the helicopter-launched Nag (HELINA) also known as Dhruvastra; a "man-portable" version (MPATGM); an air-launched version which will replace the current imaging infra-red (IIR) to millimetric-wave (mmW) active radar homing seeker; and the Nag Missile Carrier (NAMICA) "tank buster", which is a modified BMP-2 Infantry Fighting Vehicle (IFV) produced under license in India by Ordnance Factory Medak (OFMK). Development of the Nag is part of the Integrated Guided Missile Development Program (IGMDP), run by Defence Research and Development Organisation (DRDO). It is manufactured by Bharat Dynamics Limited (BDL). India's Ministry of Defence (MoD) announced on 19 July 2019 that the missile was ready for production. The Defence Research and Development Organization (DRDO) successfully completed the final trial of Nag anti-tank missile using a live warhead on a dud tank at Pokhran army ranges at 6.45 am on Oct 21, 2020.

8.8K
09 Oct 2022

Topic Review

Micronutrient Deficiency and Toxicity in Plants

Micronutrients are essential for plants. Their growth, productivity and reproduction are directly influenced by the supply of micronutrients. Currently, there are eight trace elements considered to be essential for higher plants: Fe, Zn, Mn, Cu, Ni, B, Mo, and Cl. Possibly, other essential elements could be discovered because of recent advances in nutrient solution culture techniques and in the commercial availability of highly sensitive analytical instrumentation for elemental analysis.

8.8K
27 Sep 2022

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