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Topic Review
Limit Superior and Limit Inferior
In mathematics, the limit inferior and limit superior of a sequence can be thought of as limiting (i.e., eventual and extreme) bounds on the sequence. They can be thought of in a similar fashion for a function (see limit of a function). For a set, they are the infimum and supremum of the set's limit points, respectively. In general, when there are multiple objects around which a sequence, function, or set accumulates, the inferior and superior limits extract the smallest and largest of them; the type of object and the measure of size is context-dependent, but the notion of extreme limits is invariant. Limit inferior is also called infimum limit, limit infimum, liminf, inferior limit, lower limit, or inner limit; limit superior is also known as supremum limit, limit supremum, limsup, superior limit, upper limit, or outer limit. The limit inferior of a sequence [math]\displaystyle{ x_n }[/math] is denoted by The limit superior of a sequence [math]\displaystyle{ x_n }[/math] is denoted by
  • 5.8K
  • 30 Nov 2022
Topic Review
Mettā
Mettā (Pali) or maitrī (Sanskrit) means benevolence, loving-kindness, friendliness, amity, good will, and active interest in others. It is the first of the four sublime states (Brahmavihāras) and one of the ten pāramīs of the Theravāda school of Buddhism. The cultivation of benevolence (mettā bhāvanā) is a popular form of meditation in Buddhism. It is a part of the four immeasurables in Brahmavihara (divine abidings) meditation. Metta as 'compassion meditation' is often practiced in Asia by broadcast chanting, wherein monks chant for the laity. The compassion and universal loving-kindness concept of Metta is discussed in the Metta Sutta of Buddhism, and is also found in the ancient and medieval texts of Hinduism and Jainism as Metta or Maitri. Small sample studies on the potential of loving-kindness meditation approach on patients suggest potential benefits. However, peer reviews question the quality and sample size of these studies, then suggest caution.
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  • 28 Sep 2022
Topic Review
Floating Island
A floating island is a mass of floating aquatic plants, mud, and peat ranging in thickness from several centimeters to a few meters. Floating islands are a common natural phenomenon that are found in many parts of the world. They exist less commonly as an artificial phenomenon. Floating islands are generally found on marshlands, lakes, and similar wetland locations, and can be many hectares in size.
  • 5.8K
  • 21 Oct 2022
Topic Review
Cryptography
Cryptography, or cryptology (from Ancient Greek: "hidden, secret"; and γράφειν graphein, "to write", or -λογία -logia, "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security (data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications. Cryptography prior to the modern age was effectively synonymous with encryption, converting readable information (plaintext) to unintelligible nonsense text (ciphertext), which can only be read by reversing the process (decryption). The sender of an encrypted (coded) message shares the decryption (decoding) technique only with intended recipients to preclude access from adversaries. The cryptography literature often uses the names "Alice" (or "A") for the sender, "Bob" (or "B") for the intended recipient, and "Eve" (or "E") for the eavesdropping adversary. Since the development of rotor cipher machines in World War I and the advent of computers in World War II, cryptography methods have become increasingly complex and their applications more varied. Modern cryptography is heavily based on mathematical theory and computer science practice; cryptographic algorithms are designed around computational hardness assumptions, making such algorithms hard to break in actual practice by any adversary. While it is theoretically possible to break into a well-designed system, it is infeasible in actual practice to do so. Such schemes, if well designed, are therefore termed "computationally secure"; theoretical advances (e.g., improvements in integer factorization algorithms) and faster computing technology require these designs to be continually reevaluated, and if necessary, adapted. Information-theoretically secure schemes that cannot be broken even with unlimited computing power, such as the one-time pad, are much more difficult to use in practice than the best theoretically breakable, but computationally secure, schemes. The growth of cryptographic technology has raised a number of legal issues in the Information Age. Cryptography's potential for use as a tool for espionage and sedition has led many governments to classify it as a weapon and to limit or even prohibit its use and export. In some jurisdictions where the use of cryptography is legal, laws permit investigators to compel the disclosure of encryption keys for documents relevant to an investigation. Cryptography also plays a major role in digital rights management and copyright infringement disputes in regard to digital media.
  • 5.8K
  • 28 Nov 2022
Topic Review
Weak Interaction
In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, and gravitation. It is the mechanism of interaction between subatomic particles that is responsible for the radioactive decay of atoms. The weak interaction participates in nuclear fission, and the theory describing its behaviour and effects is sometimes called quantum flavourdynamics (QFD). However, the term QFD is rarely used, because the weak force is better understood by electroweak theory (EWT). The effective range of the weak force is limited to subatomic distances, and is less than the diameter of a proton.
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  • 27 Oct 2022
Topic Review
Theosophical Society
The Theosophical Society was an organization formed in the United States in 1875 by Helena Blavatsky to advance Theosophy. The original organization, after splits and realignments, (As of 2011) has several successors. Following the death of Blavatsky, competition within the Society between factions emerged, particularly among founding members and the organisation split between the Theosophical Society Adyar (Olcott-Besant) and the Theosophical Society Pasadena (Judge). The former group, headquartered in India , is the most widespread international group holding the name "Theosophical Society" today.
  • 5.8K
  • 29 Nov 2022
Topic Review
Theory of Addiction
Drug addiction is characterized by a loss of control over drug-seeking and -consumption, despite the profound negative consequences this has on the individual’s life [1]. While the acute effects of a substance depend on its psychoactive properties, the progression of addiction converges into a series of problems that are common and severely impact all spheres of the individual’s life, compromising interpersonal, economic, and health status. Thus, in chronic drug users it is common to present several physical problems including brain damage and atrophy, circulatory system issues, premature aging, among others. From a socio-economic perspective, common problems include homelessness, criminal behavior, unemployment, social isolation, and dependence.
  • 5.8K
  • 01 Feb 2024
Topic Review
List of Doom Source Ports
This article is a list of unofficial source ports of the Doom engine, which was originally used in the video game Doom. Most often, the source ports presented here are modifications made by the Doom community, as opposed to the official Doom versions produced by id Software or affiliated companies. The Doom engine's source code was released to the public on December 23, 1997. Although Doom was originally created for MS-DOS, the original source release was for the subsequent Linux version, due to the use of a proprietary sound library in the DOS version. The original purpose of source ports was cross-platform compatibility, but shortly after the release of the Doom source code, programmers were correcting old, unaddressed Doom bugs and deficiencies in their own source ports, and later on introducing their own modifications to enhance game features and alter gameplay. The source code was originally released under a proprietary license that prohibited commercial use and did not require programmers to provide the source code for the modifications they released in executable form, but it was later re-released on October 3, 1999 under the GNU General Public License after requests from the community.
  • 5.8K
  • 06 Feb 2023
Topic Review
Alchemy and Chemistry in Medieval Islam
Alchemy and chemistry in Islam refers to the study of both traditional alchemy and early practical chemistry (the early chemical investigation of nature in general) by scholars in the medieval Islamic world. The word alchemy was derived from the Arabic word كيمياء or kīmiyāʾ. and may ultimately derive from the ancient Egyptian word kemi, meaning black. After the fall of the Western Roman Empire, the focus of alchemical development moved to the Caliphate and the Islamic civilization. Much more is known about Islamic alchemy as it was better documented; most of the earlier writings that have come down through the years were preserved as Arabic translations.
  • 5.8K
  • 24 Nov 2022
Topic Review
Buddhist Monk
A bhikkhu (Pali: भिक्खु Sanskrit: भिक्षु , bhikṣu) is an ordained male monastic ("monk") in Buddhism. Male and female monastics ("nun", bhikkhunī, Sanskrit bhikṣuṇī) are members of the Buddhist community. The lives of all Buddhist monastics are governed by a set of rules called the prātimokṣa or pātimokkha. Their lifestyles are shaped to support their spiritual practice: to live a simple and meditative life and attain nirvana. A person under the age of 20 cannot be ordained as a bhikkhu or bhikkhuni but can be ordained as a śrāmaṇera or śrāmaṇērī.
  • 5.8K
  • 22 Nov 2022
Topic Review
Social Innovation and Vulnerable Communities
This study aims to analyze the actions of the Invisible Cities Project (ICP) as an example of social innovation and as a way of giving visibility to vulnerable communities. Initially, a theoretical framework was established to understand the possibilities of the visibility of isolated and poor communities located within the urban setting. This framework was established based on the literature that addresses the role of social innovation in cities. Then, participant observations were made in a community to analyze the initiatives that are part of the ICP. Finally, semi-structured interviews were conducted; these interviews reported the lived experiences of participants involved in the project through the narratives of the community members. Drawing from the specialized literature, it was found that this project carries out various aspects of social innovation, such as social visibility, empowerment, the articulation of different actors in society, social inclusion, and the improvement of the urban public space. The project also addresses a variety of Sustainable Development Goals (SDGs), such as eradicating poverty, promoting health and well-being, reducing inequalities, and fostering more sustainable cities and communities.
  • 5.8K
  • 29 Sep 2025
Topic Review
Gauss's Lemma (Polynomial)
In algebra, Gauss's lemma, named after Carl Friedrich Gauss, is a statement about polynomials over the integers, or, more generally, over a unique factorization domain (that is, a ring that has a unique factorization property similar to the fundamental theorem of arithmetic). Gauss's lemma underlies all the theory of factorization and greatest common divisors of such polynomials. Gauss's lemma asserts that the product of two primitive polynomials is primitive (a polynomial with integer coefficients is primitive if it has 1 as a greatest common divisor of its coefficients). A corollary of Gauss's lemma, sometimes also called Gauss's lemma, is that a primitive polynomial is irreducible over the integers if and only if it is irreducible over the rational numbers. More generally, a primitive polynomial has the same complete factorization over the integers and over the rational numbers. In the case of coefficients in a unique factorization domain R, "rational numbers" must be replaced by "field of fractions of R". This implies that, if R is either a field, the ring of integers, or a unique factorization domain, then every polynomial ring (in one or several indeterminates) over R is a unique factorization domain. Another consequence is that factorization and greatest common divisor computation of polynomials with integers or rational coefficients may be reduced to similar computations on integers and primitive polynomials. This is systematically used (explicitly or implicitly) in all implemented algorithms (see Polynomial greatest common divisor and Factorization of polynomials). Gauss's lemma, and all its consequences that do not involve the existence of a complete factorization remain true over any GCD domain (an integral domain over which greatest common divisors exist). In particular, a polynomial ring over a GCD domain is also a GCD domain. If one calls primitive a polynomial such that the coefficients generate the unit ideal, Gauss's lemma is true over every commutative ring. However, some care must be taken, when using this definition of primitive, as, over a unique factorization domain that is not a principal ideal domain, there are polynomials that are primitive in the above sense and not primitive in this new sense.
  • 5.8K
  • 28 Nov 2022
Topic Review
Overall Equipment Effectiveness
Overall equipment effectiveness (OEE) is a key performance indicator used to measure equipment productivity. The purpose of this study is to review and analyze the evolution of OEE, present modifications made over the original model and identify future development areas.
  • 5.8K
  • 12 Apr 2021
Topic Review Peer Reviewed
The New Sociology of Religion
The new sociology of religion differs from the classical and mainstream sociology, which was in force until the end of the last century, in that it no longer considers religion only as an independent variable, but places it together with other dependent variables, so that it becomes possible to investigate new themes, especially those that do not consider religious involvement—from atheism to the phenomenon of ‘nones’ (non-believers and non-practicing), from spirituality to forms of para-religions and quasi-religions and the varied set of multiple religions. 
  • 5.8K
  • 13 Apr 2022
Topic Review
Autonomous Driving Technologies in Electric Vehicles
In response to severe environmental and energy crises, the world is increasingly focusing on electric vehicles (EVs) and related emerging technologies. Sensory, control, and telematics technologies are the keys to reliable autonomous driving. The integration and complementarity of EVs and autonomous driving will be an important opportunity for future smart transportation and smart cities. 
  • 5.8K
  • 01 Sep 2022
Topic Review
Folic Acid, Vitamin B12 and Chronic Kidney Disease
Patients affected by chronic kidney disease (CKD) or end-stage renal disease (ESRD) experience a huge cardiovascular risk and cardiovascular events represent the leading causes of death. Folic acid and vitamin B12 could not only be mere cofactors in the homocysteine metabolism; they may have a direct action in determining tissue damage and cardiovascular risk. 
  • 5.8K
  • 15 Oct 2021
Topic Review
Concept Learning
Concept learning, also known as category learning, concept attainment, and concept formation, is defined by Bruner, Goodnow, & Austin (1967) as "the search for and listing of attributes that can be used to distinguish exemplars from non exemplars of various categories". More simply put, concepts are the mental categories that help us classify objects, events, or ideas, building on the understanding that each object, event, or idea has a set of common relevant features. Thus, concept learning is a strategy which requires a learner to compare and contrast groups or categories that contain concept-relevant features with groups or categories that do not contain concept-relevant features. In a concept learning task, a human or machine learner is trained to classify objects by being shown a set of example objects along with their class labels. The learner simplifies what has been observed by condensing it in the form of an example. This simplified version of what has been learned is then applied to future examples. Concept learning may be simple or complex because learning takes place over many areas. When a concept is difficult, it is less likely that the learner will be able to simplify, and therefore will be less likely to learn. Colloquially, the task is known as learning from examples. Most theories of concept learning are based on the storage of exemplars and avoid summarization or overt abstraction of any kind.
  • 5.8K
  • 17 Oct 2022
Topic Review
Sustainable Valorization of Sugarcane Waste from Sugarcane Processing
Sugarcane is a lignocellulosic crop and the juice extracted from its stalks provides the raw material for 86% of sugar production. Globally, sugarcane processing to obtain sugar and/or ethanol generates more than 279 million tons of solid and liquid waste annually, as well as by-products; namely, straws, bagasse, press mud, wastewater, ash from bagasse incineration, vinasse from ethanol distillation, and molasses. If not properly managed, this waste will pose risks to both environmental factors and human health. Valorization of waste has gained momentum, having an important contribution to the fulfillment of policies and objectives related to sustainable development and circular bioeconomy. Various technologies are well-established and implemented for the valorization of waste and by-products from sugarcane processing, while other innovative technologies are still in the research and development stage, with encouraging prospects.
  • 5.8K
  • 19 Sep 2022
Topic Review
Constraints Accounting
Constraints accounting (CA) allow some variations generally accepted accounting principles(GAAP) when reporting financial statements of company and these variations do not violate the GAAP in light of recognised CA. CA contains explicit consideration of the role of constraints in accounting and constraints relate to limitations when providing financial information. The definition of a constraint is a regulation which belongs to prescribed bounds and there are four main types of constraints which are the cost-benefit relationship, materiality, industry practices, and conservatism, and these constraints are also accounting guidelines which border the hierarchy of qualitative information.
  • 5.8K
  • 01 Nov 2022
Topic Review
Shambhala
In Tibetan Buddhist tradition, Shambhala (Sanskrit: शम्भल Śambhala, also spelled Shambala or Shamballa; Tibetan: བདེ་འབྱུང, Wylie: Bde'byung; Chinese: 香巴拉; pinyin: Xiāngbālā) is a mythical kingdom. Shambhala is mentioned in the Kalacakra Tantra. The Bon scriptures speak of a closely related land called Tagzig Olmo Lung Ring. The Sanskrit name is taken from the name of a city mentioned in the Hindu Puranas, probably in reference to Sambhal in Uttar Pradesh. The mythological relevance of the place originates with a prophecy in Vishnu Purana (4.24) according to which Shambhala will be the birthplace of Kalki, the final incarnation of Vishnu, who will usher in a new Age (Satya Yuga).
  • 5.8K
  • 01 Dec 2022
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