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Topic Review
False Position Method
In mathematics, the false position method or regula falsi is a very old method for solving an equation in one unknown, that, in modified form, is still in use. In simple terms, the method is the trial and error technique of using test ("false") values for the variable and then adjusting the test value according to the outcome. This is sometimes also referred to as "guess and check". Versions of the method predate the advent of algebra and the use of equations. As an example, consider problem 26 in the Rhind papyrus, which asks for a solution of (written in modern notation) the equation x + x/4 = 15. This is solved by false position, using a technique that predates formally written equations. First, guess that x = 4 to obtain, on the left, 4 + 4/4 = 5. This guess is a good choice since it produces an integer value. However, 4 is not the solution of the original equation, as it gives a value which is three times too small. To compensate, multiply x (currently set to 4) by 3 and substitute again to get 12 + 12/4 = 15, verifying that the solution is x = 12. Modern versions of the technique employ systematic ways of choosing new test values and are concerned with the questions of whether or not an approximation to a solution can be obtained, and if it can, how fast can the approximation be found.
  • 4.9K
  • 15 Nov 2022
Topic Review
Time Management in Higher Education
Time management is regarded as an important prerequisite for effective and efficient learning in higher education. However, university students’ time management frequently proves to be deficient, especially with freshman students, who can therefore benefit from appropriate time management interventions.
  • 4.9K
  • 05 May 2022
Topic Review
Coping (Psychology)
In psychology, coping means to invest own conscious effort, to solve personal and interpersonal problems, in order to try to master, minimize or tolerate stress and conflict. The psychological coping mechanisms are commonly termed coping strategies or coping skills. The term coping generally refers to adaptive (constructive) coping strategies. That is strategies which reduce stress. In contrast, other coping strategies may be coined as maladaptive, if they increase stress. Maladaptive coping is therefore also described, when looking at the outcome, as non-coping. Furthermore, the term coping generally refers to reactive coping, i.e. the coping response which follows the stressor. This differs from proactive coping, in which a coping response aims to neutralize a future stressor. Subconscious or non-conscious strategies (e.g. defense mechanisms) are generally excluded from the area of coping. The effectiveness of the coping effort depends on the type of stress, the individual, and the circumstances. Coping responses are partly controlled by personality (habitual traits), but also partly by the social environment, particularly the nature of the stressful environment.
  • 4.9K
  • 17 Oct 2022
Topic Review
Digital Image Watermarking Techniques
Image authentication is an extremely significant concern for the digital revolution, as it is easy to alter any image. In the last few decades, it has been an urgent concern for researchers to ensure the authenticity of digital images. Based on the desired applications, several suitable watermarking techniques have been developed to mitigate this concern. However, it is tough to achieve a watermarking system that is simultaneously robust and secure. This paper gives details of standard watermarking system frameworks and lists some standard requirements that are used in designing watermarking techniques for several distinct applications. The current trends of digital image watermarking techniques are also reviewed to find state-of-the-art methods and their limitations. Some conventional attacks are discussed, and future research directions are given.
  • 4.9K
  • 29 Oct 2020
Topic Review
Maize Breeding
Maize or corn (Zea mays L.), a plant species particularly generous in its production potential and in its wide diversity of uses, is fundamental for the development of a modern and efficient agriculture. Globally, maize ranks third in area and first in production, ahead of wheat and rice. Due to the large areas corn occupies, but especially to its yielding performance, maize is a major source of food for the world’s population. In addition to its nutritional importance for humans, corn is also basic food for animal feed and valuable raw material for industrial processing. The importance of corn for human health results from the fact that it is a food rich in nutrients, especially energy of 355 kcal per 100 g flour with 15% moisture, compared to 352 kcal for wheat flour, 348 kcal for rye flour, and 346 kcal for hulled barley. As food, maize also has some shortcomings, of which that the low amount of some essential amino acids was noted, such as lysine and tryptophan. Maize is also a valuable raw material for industry, extracting oil, starch, alcohol, glucose, and other products such as syrup, pectin, dextrin, plastics, lactic acid, acetic acid, acetone, dyes, and synthetic rubber from its grains. Paper, cardboard, and nitrocellulose can be made from corn stalks. Every part of the maize plant has economic worth, including the grain, leaves, stalk, tassel, and cob, which can be used to make a variety of food and non-food goods. Maize breeding research has traditionally concentrated on enhancing productive potential in newly created maize varieties because this criterion ensures a crop’s economic efficiency. Nowadays, genomics tools are essential for a precise, fast, and efficient breeding of crops especially in the context of climate challenges, but also may in the future represent a way to accelerate the processes of de novo domestication of the species.
  • 4.9K
  • 24 Oct 2022
Topic Review
Resistance of PVD Coatings
Due to the increasing maintenance costs of hydraulic machines related to the damages caused by cavitation erosion and/or erosion of solid particles, as well as in tribological connections, surface protection of these components is very important. Up to now, numerous investigations of resistance of coatings, mainly nitride coatings, such as CrN, TiN, TiCN, (Ti,Cr)N coatings and multilayer TiN/Ti, ZrN/CrN and TN/(Ti,Al)N coatings, produced by physical vapor deposition (PVD) method using different techniques of deposition, such as magnetron sputtering, arc evaporation or ion plating, to cavitation erosion, solid particle erosion and wear have been made. The results of these investigations, degradation processes and main test devices used are presented in this paper. An effect of deposition of mono- and multi-layer PVD coatings on duration of incubation period, cumulative weight loss and erosion rate, as well as on wear rate and coefficient of friction in tribological tests is discussed. It is shown that PVD coating does not always provide extended incubation time and/or improved resistance to mentioned types of damage. The influence of structure, hardness, residence to plastic deformation and stresses in the coatings on erosion and wear resistance is discussed. In the case of cavitation erosion and solid particle erosion, a limit value of the ratio of hardness (H) to Young’s modulus (E) exists at which the best resistance is gained. In the case of tribological tests, the higher the H/E ratio and the lower the coefficient of friction, the lower the wear rate, but there are also many exceptions
  • 4.9K
  • 13 Oct 2020
Topic Review
The Resilient City
A resilient city can be defined as a community that has the capacity to manage unexpected events and face stresses and shocks, preserving and innovating its social, economic, and infrastructural system.
  • 4.9K
  • 21 Jul 2021
Topic Review
Coherence
In physics, two wave sources are coherent if their frequency and waveform are identical. Coherence is an ideal property of waves that enables stationary (i.e. temporally or spatially constant) interference. It contains several distinct concepts, which are limiting cases that never quite occur in reality but allow an understanding of the physics of waves, and has become a very important concept in quantum physics. More generally, coherence describes all properties of the correlation between physical quantities of a single wave, or between several waves or wave packets. Interference is the addition, in the mathematical sense, of wave functions. A single wave can interfere with itself, but this is still an addition of two waves (see Young's slits experiment). Constructive or destructive interference are limit cases, and two waves always interfere, even if the result of the addition is complicated or not remarkable. When interfering, two waves can add together to create a wave of greater amplitude than either one (constructive interference) or subtract from each other to create a wave of lesser amplitude than either one (destructive interference), depending on their relative phase. Two waves are said to be coherent if they have a constant relative phase. The amount of coherence can readily be measured by the interference visibility, which looks at the size of the interference fringes relative to the input waves (as the phase offset is varied); a precise mathematical definition of the degree of coherence is given by means of correlation functions. Spatial coherence describes the correlation (or predictable relationship) between waves at different points in space, either lateral or longitudinal. Temporal coherence describes the correlation between waves observed at different moments in time. Both are observed in the Michelson–Morley experiment and Young's interference experiment. Once the fringes are obtained in the Michelson interferometer, when one of the mirrors is moved away gradually from the beam-splitter, the time for the beam to travel increases and the fringes become dull and finally disappear, showing temporal coherence. Similarly, in a double-slit experiment, if the space between the two slits is increased, the coherence dies gradually and finally the fringes disappear, showing spatial coherence. In both cases, the fringe amplitude slowly disappears, as the path difference increases past the coherence length.
  • 4.9K
  • 16 Nov 2022
Topic Review
Eckankar
Eckankar is a new religious movement founded by Paul Twitchell in 1965. It is a non-profit religious group with members in over one hundred countries. The spiritual home is the Temple of Eck in Chanhassen, Minnesota. Eckankar is not affiliated with any other religious group. The movement teaches simple spiritual exercises, such as singing "Hu", called "a love song to God", to experience the Light and Sound of God and recognize the presence of the Holy Spirit.
  • 4.9K
  • 02 Nov 2022
Biography
Luther Gulick
Luther Halsey Gulick (1892–1993) was an American political scientist, Eaton Professor of Municipal Science and Administration at Columbia University, and Director of its Institute of Public Administration, known as an expert on public administration. Luther Halsey Gulick was born January 17, 1892 in Osaka , Japan . His father was congregationalist missionary Sidney Lewis Gulick (1860–1945
  • 4.9K
  • 06 Dec 2022
Topic Review Peer Reviewed
Reinforced Concrete Infilled Frames
Masonry-Infilled Reinforced Concrete Frames are a very widespread structural typology all over the world for civil, strategic or productive uses. The damages due to these masonry panels can be life threatening to humans and can severely impact economic losses, as shown during past earthquakes. In fact, during a seismic event, most victims are caused by the collapse of buildings or due to nonstructural elements. The damage caused by an earthquake on nonstructural elements, i.e., those not belonging to the actual structural body of the building, is important for the purposes of a more general description of the effects and, of course, for economic estimates. In fact, after an earthquake, albeit of a low entity, it is very frequent to find even widespread damages of nonstructural elements causing major inconveniences even if the primary structure has reported minor damages. In recent years, many territories have been hit worldwide by strong seismic sequences, which caused widespread damages to the nonstructural elements and in particular to the masonry internal partitions and the masonry infill panels of the buildings in reinforced concrete, with damage to the floor and out-of-plane expulsions/collapses of single layers. Unfortunately, these critical issues have arisen not only in historic, but also in recent buildings with reinforced concrete, in many cases exhibiting inadequate seismic behavior, only partly attributable to the intrinsic vulnerability of the masonry panels against seismic actions. Such problems are due to the following aspects: lack of attention to construction details in the realization of the construction, use of poor-quality materials, and above all lack of design tools for the infill masonry walls. In 2018, regarding the design of nonstructural elements, the formulation of floor spectra has been recently introduced in Italy. This entry article wants to focus on all these aspects, describing the state of the art, the literature studies and the design problems to be solved.
  • 4.9K
  • 13 Apr 2022
Topic Review
Domain Fronting
Domain fronting is a technique for Internet censorship circumvention that uses different domain names in different communication layers of an HTTPS connection to discreetly connect to a different target domain than is discernable to third parties monitoring the requests and connections. Due to quirks in security certificates, the redirect systems of the content delivery networks (CDNs) used as 'domain fronts', and the protection provided by HTTPS, censors are typically unable to differentiate circumvention ("domain-fronted") traffic from overt non-fronted traffic for any given domain name. As such they are forced to either allow all traffic to the domain front—including circumvention traffic—or block the domain front entirely, which may result in expensive collateral damage and has been likened to "blocking the rest of the Internet".[note 1] Domain fronting does not conform to HTTP standards that require the SNI extension and HTTP Host header to contain the same domain. Large cloud service providers, including Amazon and Google, now actively prohibit domain fronting, which has made it "largely non-viable"[note 1] as a censorship bypass technique.
  • 4.9K
  • 06 Oct 2022
Topic Review
Acute and Chronic Stress Reactions and HPA Axis
Due to the influence of various stressful stimuli, psychological stress alters the homeostasis of the organism. Consequently, the organism reacts, and the sympathetic-adrenal-medullary (SAM) system and the hypothalamic-pituitary-adrenal (HPA) axis are activated, producing and releasing specific hormones. In addition to acute stress, chronic psychological stress also activates the HPA axis, which causes elevated glucocorticoid levels. 
  • 4.9K
  • 26 Oct 2022
Topic Review
Rotating Packed Beds
In this study, a comprehensive review was conducted of the process intensification equipment used for gas absorption processes, which are known as rotating packed beds (RPB) or HiGee contactors. Using centrifugal acceleration in RPBs intensifies the MT coefficient, and this leads to a reduction in the packing volume and energy consumption in comparison with packed beds. The gas velocity and flow area change radially in RPBs; therefore, MT coefficients change from point to point in contactors, but there is no general theory for this, and the prediction of MT coefficients in RPBs is theoretically complicated.
  • 4.9K
  • 11 Aug 2021
Topic Review
Water Well
A water well is an excavation or structure created in the ground by digging, driving, boring, or drilling to access groundwater in underground aquifers. The well water is drawn by a pump, or using containers, such as buckets, that are raised mechanically or by hand. Wells were first constructed at least eight thousand years ago and historically vary in construction from a simple scoop in the sediment of a dry watercourse to the qanats of Iran, and the stepwells and sakiehs of India. Placing a lining in the well shaft helps create stability, and linings of wood or wickerwork date back at least as far as the Iron Age. Wells have traditionally been sunk by hand digging, as is the case in rural areas of the developing world. These wells are inexpensive and low-tech as they use mostly manual labour, and the structure can be lined with brick or stone as the excavation proceeds. A more modern method called caissoning uses pre-cast reinforced concrete well rings that are lowered into the hole. Driven wells can be created in unconsolidated material with a well hole structure, which consists of a hardened drive point and a screen of perforated pipe, after which a pump is installed to collect the water. Deeper wells can be excavated by hand drilling methods or machine drilling, using a bit in a borehole. Drilled wells are usually cased with a factory-made pipe composed of steel or plastic. Drilled wells can access water at much greater depths than dug wells. Two broad classes of well are shallow or unconfined wells completed within the uppermost saturated aquifer at that location, and deep or confined wells, sunk through an impermeable stratum into an aquifer beneath. A collector well can be constructed adjacent to a freshwater lake or stream with water percolating through the intervening material. The site of a well can be selected by a hydrogeologist, or groundwater surveyor. Water may be pumped or hand drawn. Impurities from the surface can easily reach shallow sources and contamination of the supply by pathogens or chemical contaminants needs to be avoided. Well water typically contains more minerals in solution than surface water and may require treatment before being potable. Soil salination can occur as the water table falls and the surrounding soil begins to dry out. Another environmental problem is the potential for methane to seep into the water.
  • 4.9K
  • 27 Oct 2022
Topic Review
Unmanned Ground Vehicles
Unmanned ground vehicles (UGVs) have great potential in the application of both civilian and military fields, and have become the focus of research in many countries. Environmental perception technology is the foundation of UGVs, which is of great significance to achieve a safer and more efficient performance.
  • 4.9K
  • 22 Feb 2021
Topic Review
Dead Cas Systems
The gene editing tool CRISPR-Cas has become the foundation for developing numerous molecular systems used in research and, increasingly, in medical practice. In particular, Cas proteins devoid of nucleolytic activity (dead Cas proteins; dCas) can be used to deliver functional cargo to programmed sites in the genome. In this review, we describe current CRISPR systems used for developing different dCas-based molecular approaches and summarize their most significant applications
  • 4.9K
  • 30 Oct 2020
Topic Review
Non-invasive Imaging Technology
Non-invasive imaging technology is a commonly used diagnostic tool in modern medicine. Commonly used are computed tomography (CT), positron emission tomography (PET), ultrasound (US), PAI (photoacoustic imaging) and MRI (magnetic resonance imaging) . This review explores the use of these modalities for imaging biodegradable implants.
  • 4.9K
  • 27 Jul 2021
Topic Review
Idolatry in Sikhism
Sikhism prohibits idolatry, in accordance with mainstream Khalsa norms and the teachings of the Sikh Gurus, a position that has been accepted as orthodox. Growing Sikh popular discontent with Gurdwara administration and practices during the 1800s, revivalist movements in the mid-1800s who opposed idol worship like the Nirankaris and the Namdharis (who however have followed a living guru since its inception), and the encroachment of Brahmanical customs in the Golden Temple during that period, led to the establishment of the Singh Sabha Movement in 1873, in which the Tat Khalsa faction, dominant since the early 1880s, pushed to renew and standardize the practice of Sikhism. After a period of political advancement, the Khalsa faction re-established direct control over Gurdwara management over the Udasi and Hindu mahants, who institutionalized idol worship and would eventually identify with the Sanatan Sikhs, who identified with the Brahmanical social structure and considered idol worship as not harmful. The mahants had gained control of Gurdwaras after heavy Mughal persecution forced the Khalsa to relinquish control of the Gurdwaras and vacate the Punjab plains in the 1700s; they were most prominent in the 1800s. The Arya Samaj, opponents of the Sikhs, asserted that many Sikhs accepted idols and their worship within Sikh temples, unlike Khalsa Sikhs who strongly opposed the practice. In 1905, after re-establishing institutional control, the Khalsa managed to have removed the idols installed during the preceding period, as well as ending mahant administration and the practice of other non-Sikh, Brahmanical rituals in the process, considering them "Hindu accretions" and "Brahmanical stranglehold," amidst a major controversy within the Sikh community of that era. The prohibition, state Fenech and McLeod, has also served a means to assert Sikhism differs from Hinduism.
  • 4.9K
  • 04 Nov 2022
Topic Review
Plasmonic Biosensors
Biosensors have globally been considered as biomedical diagnostic tools required in abundant areas including the development of diseases, detection of viruses, diagnosing ecological pollution, food monitoring, and a wide range of other diagnostic and therapeutic biomedical research. Recently, the broadly emerging and promising technique of plasmonic resonance has proven to provide label-free and highly sensitive real-time analysis when used in biosensing applications.
  • 4.9K
  • 26 Apr 2022
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