Your browser does not fully support modern features. Please upgrade for a smoother experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Prehistoric Paintings in Magura Cave
The paintings are made of bat guano applied over limestone, therefore two sets of laboratory specimens were considered: stone specimens and stone specimens covered with a layer of sterilized bat guano. The two investigated treatments were a commercial product based on ethyl silicate (“ES”) and a solution of diammonium hydrogen phosphate (“DAP”), aimed at forming calcium phosphates. The results of the study indicate that both treatments were able to increase mechanical properties of stone, the increase being higher for “DAP”. Both consolidants caused acceptable color changes, but the “ES” treatment significantly decreased stone wettability, water absorption and water vapor permeability, while the “DAP” treatment slightly affected those properties. In the stone+guano specimens, the presence of the guano layer affected the penetration of the consolidants, thus partly reducing their effectiveness. Compared to the stone samples, the guano layer experienced a more intense color change, alongside visible cracking. However, the adopted methodology to replicate the cave paintings was not completely successful, as the so-deposited guano layer was very prone to detachment when dry, unlike cave paintings. Future work will be dedicated to assess the consolidant performance onto samples that resemble even more closely the conditions of the cave paintings, by improving the methodology for the guano layer deposition and by contaminating specimens with soluble salts before consolidant application.
  • 8.6K
  • 02 Nov 2020
Topic Review
Natural Emulsion Stabilizers
Natural emulsion stabilizers are polymers of amino acid, nucleic acid, carbohydrate, etc., which are derived from microorganisms, bacteria, and other organic materials. Plant and animal proteins are basic sources of natural emulsion stabilizers. Pea protein-maltodextrin and lentil protein feature entrapment capacity up to 88%, (1–10% concentrated), zein proteins feature 74–89% entrapment efficiency, soy proteins in various concentrations increase dissolution, retention, and stability to the emulsion and whey proteins, egg proteins, and proteins from all other animals are applicable in membrane formation and encapsulation to stabilize emulsion/nanoemulsion. In pharmaceutical industries, phospholipids, phosphatidyl choline (PC), phosphatidyl ethanol-amine (PE), and phosphatidyl glycerol (PG)-based stabilizers are very effective as emulsion stabilizers. Lecithin (a combination of phospholipids) is used in the cosmetics and food industries. Various factors such as temperature, pH, droplets size, etc. destabilize the emulsion. Therefore, the emulsion stabilizers are used to stabilize, preserve and safely deliver the formulated drugs, also as a preservative in food and stabilizer in cosmetic products. Natural emulsion stabilizers offer great advantages because they are naturally degradable, ecologically effective, non-toxic, easily available in nature, non-carcinogenic, and not harmful to health.
  • 8.6K
  • 19 Jan 2022
Topic Review
White–Juday Warp-Field Interferometer
The White–Juday warp-field interferometer is an experiment designed to detect a microscopic instance of a warping of spacetime. If such a warp is detected, it is hoped that more research into creating an Alcubierre warp bubble will be inspired. A research team led by Harold "Sonny" White in collaboration with Dr. Richard Juday at the NASA Johnson Space Center and Dakota State University are conducting experiments, but results so far have been inconclusive.
  • 8.6K
  • 24 Nov 2022
Topic Review
Social Control
Social control refers to the mechanisms, norms, and practices through which societies regulate individual behavior and maintain order. It encompasses both formal institutions such as laws and regulations, as well as informal social norms and expectations. Social control mechanisms serve to reinforce conformity to societal norms, values, and expectations, while also deterring deviant behavior through sanctions and rewards.
  • 8.6K
  • 26 Jan 2024
Topic Review
List of Folk Heroes
This is a list of folk heroes.
  • 8.6K
  • 17 Oct 2022
Topic Review
Classical Nucleation Theory
Crystal nucleation determining the formation and assembly pathway of first organic materials is the central science of various scientific disciplines such as chemical, geochemical, biological, and synthetic materials. Classical nucleation theory (CNT)  applies to systems of small organic molecules with an emphasis on the molecular interpretation of nucleation kinetics. CNT holds that density fluctuations are concomitant with the development of crystalline order. In other words, a crystal nucleus has an identical structure to its bulk crystal. 
  • 8.6K
  • 22 Jul 2022
Topic Review
Compass Card (TransLink)
The Compass Card is a contactless smart card payment system primarily used for public transit in Metro Vancouver, British Columbia, Canada. It is operated by TransLink. Riders purchase a Compass Card and add fare value online, by phone, or at vending machines located at SeaBus terminals, SkyTrain and West Coast Express stations. Vending machines are also available at 18 participating London Drugs retail store locations. Compass Cards were deployed in August 2015. Full deployment for the general public took place on November 2, 2015. Since April 4, 2016, Compass Cards and Tickets have been required for all trips taken on the SkyTrain, SeaBus, and West Coast Express. In June 2016, TransLink reported that 100 percent of monthly pass users and 95 percent of all other users have switched over to the new format, totalling more than 915,000 customers.
  • 8.6K
  • 14 Oct 2022
Topic Review
SoundCloud
SoundCloud is an online audio distribution platform and music sharing website based in Berlin, Germany that enables its users to upload, promote, and share audio.
  • 8.6K
  • 20 Oct 2022
Topic Review
Essential Oil Prevents COVID-19
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV‑2), also known as coronavirus disease-2019 (COVID-19), is a pandemic disease that has been declared as modern history’s gravest health emergency worldwide. Until now, no precise treatment modality has been developed. The angiotensin-converting enzyme 2 (ACE2) receptor, a host cell receptor, has been found to play a crucial role in virus cell entry; therefore, ACE2 blockers can be a potential target for anti-viral intervention. In this study, we evaluated the ACE2 inhibitory effects of 10 essential oils. Among them, geranium and lemon oils displayed significant ACE2 inhibitory effects in epithelial cells. In addition, immunoblotting and qPCR analysis also confirmed that geranium and lemon oils possess potent ACE2 inhibitory effects. Furthermore, the gas chromatography-mass spectrometry (GC–MS) analysis displayed 22 compounds in geranium oil and 9 compounds in lemon oil. Citronellol, geraniol, and neryl acetate were the major compounds of geranium oil and limonene that represented major compound of lemon oil. Next, we found that treatment with citronellol and limonene significantly downregulated ACE2 expression in epithelial cells. The results suggest that geranium and lemon essential oils and their derivative compounds are valuable natural anti-viral agents that may contribute to the prevention of the invasion of SARS-CoV-2/COVID-19 into the human body.
  • 8.6K
  • 13 Feb 2021
Topic Review
Food Heritage
The entry explores the concept of food heritage, focusing mainly on the anthropological, geographical, and sociological debate. Although the review identifies some conceptualisations that frame heritage in the food and gastronomic domains, it also shows the high degree of fragmentation of the debate. In so doing, it sheds light on how the concept of food heritage from a theoretical point of view is still in progress.
  • 8.6K
  • 02 Feb 2022
Topic Review
Correlation and Dependence
In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. In the broadest sense correlation is any statistical association, though it commonly refers to the degree to which a pair of variables are linearly related. Familiar examples of dependent phenomena include the correlation between the height of parents and their offspring, and the correlation between the price of a good and the quantity the consumers are willing to purchase, as it is depicted in the so-called demand curve. Correlations are useful because they can indicate a predictive relationship that can be exploited in practice. For example, an electrical utility may produce less power on a mild day based on the correlation between electricity demand and weather. In this example, there is a causal relationship, because extreme weather causes people to use more electricity for heating or cooling. However, in general, the presence of a correlation is not sufficient to infer the presence of a causal relationship (i.e., correlation does not imply causation). Formally, random variables are dependent if they do not satisfy a mathematical property of probabilistic independence. In informal parlance, correlation is synonymous with dependence. However, when used in a technical sense, correlation refers to any of several specific types of mathematical operations between the tested variables and their respective expected values. Essentially, correlation is the measure of how two or more variables are related to one another. There are several correlation coefficients, often denoted [math]\displaystyle{ \rho }[/math] or [math]\displaystyle{ r }[/math], measuring the degree of correlation. The most common of these is the Pearson correlation coefficient, which is sensitive only to a linear relationship between two variables (which may be present even when one variable is a nonlinear function of the other). Other correlation coefficients – such as Spearman's rank correlation – have been developed to be more robust than Pearson's, that is, more sensitive to nonlinear relationships. Mutual information can also be applied to measure dependence between two variables.
  • 8.6K
  • 14 Oct 2022
Topic Review
Extreme Weather Events of 535–536
The extreme weather events of 535–536 were the most severe and protracted short-term episodes of cooling in the Northern Hemisphere in the last 2,000 years. The event is thought to have been caused by an extensive atmospheric dust veil, possibly resulting from a large volcanic eruption conjectured to be either in Asia, the Americas, Europe, or other locations. Its effects were widespread, causing unseasonable weather, crop failures, and famines worldwide.
  • 8.6K
  • 23 Nov 2022
Topic Review
Lisbon Treaty
The Lisbon Treaty has brought significant changes to the institutional structure of the European Union. The traditional three pillar system has been abolished and provisions regarding formal Union institutions have been amended. The aim of this encyclopedia entry is to briefly describe the functioning of each of the formal EU institutions after the Lisbon amendment. More specifically, their main tasks and powers will be shortly presented, whilst more extensive bibliography will be provided. In this regard, the reader will be in position to understand the fundamentals of the EU institutional structure and also find valuable sources for further research.
  • 8.6K
  • 16 Mar 2021
Topic Review
Peroxisomal β-Oxidation
It is not paradoxical that what has been overlooked tends to be of great importance. Peroxisomes, the widely distributed organelles in the body, play irreplaceable roles in cellular metabolism, especially in fatty acid oxidation (FAO) and the generation and elimination of reactive oxygen species (ROS).
  • 8.6K
  • 15 Jul 2022
Topic Review
Expectation–Disconfirmation Theory and Brand
Combining brand equity indicators with Expectation–Disconfirmation Theory (EDT) provides insight into the hardly measurable influential variables of brand loyalty and brand equity evaluation. The results suggest that the satisfaction level (i.e., product evaluation) can be explained in more depth by the divided response shift indicator in the case of a familiar, low involvement product such as mineral water. It can be stated that the positive and negative disconfirmations of the response shift, which measures the weight of a brand in the overall evaluation of a product, can provide accurate information for brand managers.
  • 8.6K
  • 26 Jul 2022
Topic Review
Responsive Architecture
Responsive architecture is a type of architecture, an artificial entity, that reacts to data and information collected by a variety of types of sensors. It is also defined as an interactive and collective platform where diverse computing or operating systems are executed, leading to architectural behaviors like changing forms or services.
  • 8.6K
  • 20 May 2021
Topic Review
Mango (Mangifera indica L.) Leaves
Mango (Mangifera indica L.) ascribed to the family Anacardiaceae has been adjudged as the vital traditionally significant and one of the most economically important tropical fruit crop globally.
  • 8.5K
  • 28 May 2021
Topic Review
Sone Ki Chidiya
"Sone Ki Chidiya" which means "A golden bird" but have you wondered why India was known by this name? Let's find out in this article
  • 8.5K
  • 06 May 2024
Topic Review
Fresh Fruit Supply Chain Optimization
The fresh fruit chain has been recognized as a very important and strategic part of the economic development of many countries. The planning framework for production and distribution is highly complex as a result. Mathematical models have been developed over the decades to deal with this complexity. This review focuses on the recent progress in mathematically based decision making to account for uncertainties in the fresh fruit supply chain
  • 8.5K
  • 27 Jul 2021
Topic Review
Phenomenology
Phenomenology (from Greek φαινόμενον, phainómenon "that which appears" and λόγος, lógos "study") is the philosophical study of the structures of experience and consciousness. As a philosophical movement it was founded in the early years of the 20th century by Edmund Husserl and was later expanded upon by a circle of his followers at the universities of Göttingen and Munich in Germany . It then spread to France , the United States , and elsewhere, often in contexts far removed from Husserl's early work. Phenomenology is not a unified movement; rather, the works of different authors share a 'family resemblance' but with many significant differences. Gabriella Farina states:Phenomenology, in Husserl's conception, is primarily concerned with the systematic reflection on and study of the structures of consciousness and the phenomena that appear in acts of consciousness. Phenomenology can be clearly differentiated from the Cartesian method of analysis which sees the world as objects, sets of objects, and objects acting and reacting upon one another. Husserl's conception of phenomenology has been criticized and developed not only by him but also by students and colleagues such as Edith Stein, Max Scheler, Roman Ingarden, and Dietrich von Hildebrand, by existentialists such as Nicolai Hartmann, Gabriel Marcel, Maurice Merleau-Ponty, and Jean-Paul Sartre, by hermeneutic philosophers such as Martin Heidegger, Hans-Georg Gadamer, and Paul Ricoeur, by later French philosophers such as Jean-Luc Marion, Michel Henry, Emmanuel Levinas, and Jacques Derrida, by sociologists such as Alfred Schütz and Eric Voegelin, and by Christian philosophers, such as Dallas Willard.
  • 8.5K
  • 28 Nov 2022
  • Page
  • of
  • 2727
Featured Entry Collections
>>

Featured Reprints

>>
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Medieval Royal Iconography
Academic Video Service
Feedback