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Topic Review
Envy
Envy (from Latin invidia) is an emotion which occurs when a person lacks another's superior quality, achievement, or possession and either desires it or wishes that the other lacked it. Aristotle defined envy as pain at the sight of another's good fortune, stirred by "those who have what we ought to have". Bertrand Russell said that envy was one of the most potent causes of unhappiness. Not only is the envious person rendered unhappy by their envy, Russell argued, but that person may also wish to inflict misfortune on others to reduce their status.
  • 3.1K
  • 14 Nov 2022
Topic Review
Informal Learning
Informal learning is characterized “by a low degree of planning and organizing in terms of the learning context, learning support, learning time, and learning objectives”. It differs from formal learning, non-formal learning, and self-regulated learning, because it has no set objective in terms of learning outcomes, but an intent to act from the learner’s standpoint (e.g., to solve a problem). Typical mechanisms of informal learning include trial and error or learning-by-doing, modeling, feedback, and reflection. For learners this includes heuristic language building, socialization, enculturation, and play. Informal learning is a pervasive ongoing phenomenon of learning via participation or learning via knowledge creation, in contrast with the traditional view of teacher-centered learning via knowledge acquisition. Estimates suggest that about 70-90 percent of adult learning takes place informally and outside educational institutions. The term is often conflated, however, with non-formal learning, and self-directed learning. It is widely used in the context of corporate training and education in relation to return on investment (ROI), or return on learning (ROL). It is also widely used when referring to science education, in relation to citizen science, or informal science education. The conflated meaning of informal and non-formal learning explicates mechanisms of learning that organically occur outside the realm of traditional instructor-led programs, e.g., reading self-selected books, participating in self-study programs, navigating performance support materials and systems, incidental skills practice, receptivity of coaching or mentoring, seeking advice from peers, or participation in communities of practice, to name a few. Informal learning is common in communities where individuals have opportunities to observe and participate in social activities. Advantages of informal learning cited include flexibility and adaptation to learning needs, direct transfer of learning into practice, and rapid resolution of (work-related) problems. For improving employees' performance, task execution is considered the most important source of learning.
  • 3.1K
  • 12 Dec 2022
Topic Review
Short Text Clustering Algorithms
Short text clustering (STC) has become a critical task for automatically grouping various unlabelled texts into meaningful clusters. STC is a necessary step in many applications, including Twitter personalization, sentiment analysis, spam filtering, customer reviews and many other social network-related applications.
  • 3.1K
  • 18 Jan 2023
Topic Review
Unfired Clay Bricks
Bricks are typically made through the high-temperature firing process or by stabilizing the mixture with binders such as lime and cement. These bricks have a large carbon footprint and high levels of grey energy. In many parts of the world, the excessive use of clay as a natural raw material for the production of conventional bricks will lead to its scarcity. The mixing of clay with lignocellulosic ash during brick manufacturing leads to a better and more reliable solution that conserves scarce natural resources and reduces the impact of environmental pollution. 
  • 3.1K
  • 31 Oct 2022
Topic Review
CRISPR Therapeutics
The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) genome editing system has been the focus of intense research in the last decade due to its superior ability to desirably target and edit DNA sequences. The applicability of the CRISPR-Cas system to in vivo genome editing has acquired substantial credit for a future in vivo gene-based therapeutic. Challenges such as targeting the wrong tissue, undesirable genetic mutations, or immunogenic responses, need to be tackled before CRISPR-Cas systems can be translated for clinical use. Hence, there is an evident gap in the field for a strategy to enhance the specificity of delivery of CRISPR-Cas gene editing systems for in vivo applications. Current approaches using viral vectors do not address these main challenges and, therefore, strategies to develop non-viral delivery systems are being explored. Peptide-based systems represent an attractive approach to developing gene-based therapeutics due to their specificity of targeting, scale-up potential, lack of an immunogenic response and resistance to proteolysis. In this review, we discuss the most recent efforts towards novel non-viral delivery systems, focusing on strategies and mechanisms of peptide-based delivery systems, that can specifically deliver CRISPR components to different cell types for therapeutic and research purposes.
  • 3.1K
  • 12 Oct 2020
Topic Review
Beneficial Biological Effects of Helichrysum italicum
Helichrysum italicum (family Asteraceae), due to its various beneficial biological effects, represents an important plant in the traditional medicine of Mediterranean countries. There is a renewed interest in this medicinal plant, especially in investigations involving the isolation and identification of its bioactive compounds from extracts and essential oils, as well as in experimental validation of their pharmacological activities. The research is focused on the beneficial biological effects of Helichrysum italicum extracts, essential oils, and their major bioactive polyphenolic compounds, ranging from antioxidative, anti-inflammatory, and anticarcinogenic activities to their antiviral, antimicrobial, insecticidal, and antiparasitic effects.
  • 3.1K
  • 08 Mar 2023
Topic Review
Secondary Marine Metabolites
Secondary marine metabolites are defined as molecules with a molecular weight ranging between 100 to 1000 Da and, unlike primary marine metabolites, are often found to be unique to an organism or a specific taxonomic group of the marine source. Other than marine macroorganisms such as algae, sponges, or corals, specifically marine fungi and bacteria have shown to produce novel secondary metabolites with unique as well as diverse chemical structures that may hold the key for developing novel drugs or drug leads. Secondary marine metabolites have been found in both prokaryotic and eukaryotic microorganisms, with unicellular bacteria (e.g., Bacillus sp., Pseudomonas sp.), eukaryotic fungi (e.g., Penicillium sp., Aspergillus sp.), filamentous actinomyces (e.g., Streptomyces sp.), and terrestrial plants being the most frequently studied and versatile producers. A potential clarification why organisms produce a high assortment of bioactive secondary marine metabolites is that these molecules furnish producers with a specific advantage against competing organisms and, furthermore, act as an adaptation to ecological conditions.
  • 3.1K
  • 30 Sep 2020
Topic Review
Tracked Locomotion Systems for Ground Mobile Robots
Service robotics is presently one of the fastest-growing technological fields. Nevertheless, while Automated Guided Vehicles (AGV) moving on flat and compact grounds are already commercially available and widely used to move components and products inside industrial buildings, the extensive application of ground mobile robots in environments that are unstructured or structured for humans is a promising challenge for the next years. The important application fields are agriculture, planetary exploration, reconnaissance in dangerous situations, such as radioactive or chemical contamination, homeland security and military operations, demining, intervention in case of terrorist attacks, and surveillance.
  • 3.1K
  • 26 Aug 2022
Topic Review
African American Studies
African American studies (alternately Black studies, or Africana studies, among other terms) is an interdisciplinary academic field that is primarily devoted to the study of the history, culture, and politics of black people from the United States . African American studies are a sub-field of African diaspora studies and Africana studies, the study of the people of African origin worldwide. The field has been defined in different ways, but taken broadly, it not only studies African slave descendants but also any community of the African diaspora linked to the Americas. The field includes scholars of African American (as well as Caribbean, African, and Afro-European) literature, history, politics, and religion as well as those from disciplines such as sociology, anthropology, cultural studies, psychology, education, and many other disciplines within the humanities and social sciences. And, increasingly, African American Studies departments are hiring and partnering with STEM scholars. Intensive academic efforts to reconstruct African American history began in the late 19th century (W. E. B. Du Bois, The Suppression of the African Slave-trade to the United States of America, 1896). Among the pioneers in the first half of the 20th century were Carter G. Woodson, Herbert Aptheker, Melville Herskovits, and Lorenzo Dow Turner. Programs and departments of African American Studies were first created in the 1960s and 1970s as a result of inter-ethnic student and faculty activism at many universities, sparked by a five-month strike for black studies at San Francisco State. In February 1968, San Francisco State hired sociologist Nathan Hare to coordinate the first black studies program and write a proposal for the first Department of Black Studies; the department was created in September 1968 and gained official status at the end of the five-months strike in the spring of 1969. The creation of programs and departments in black studies was a common demand of protests and sit-ins by minority students and their allies, who felt that their cultures and interests were underserved by the traditional academic structures. Black studies is a systematic way of studying black people in the world – such as their history, culture, sociology, policies, experience, issues and religion. It is a study of the black experience and the effect of society on them and their effect within society. This study aims to, among other things, help eradicate many racial stereotypes. Black studies implements history, family structure, social and economic pressures, stereotypes, and gender relationships.
  • 3.1K
  • 04 Nov 2022
Topic Review
E-Bike Sharing System
Recent data on conventional bike and/or electric bike (e-bike) sharing systems reveal that more than 2900 systems are operating in cities worldwide, indicating the increased adoption of this alternative mode of transportation. Addressing the existing gap in the literature regarding the deployment of e-bike sharing systems (e-BSSs) in particular, this paper reviews their spatio-temporal characteristics, and attempts to (a) map the worldwide distribution of e-BSSs, (b) identify temporal trends in terms of annual growth/expansion of e-BSS deployment worldwide and (c) explore the spatial characteristics of the recorded growth, in terms of adoption on a country scale, population coverage and type of system/initial fleet sizes. To that end, it examines the patterns identified from the global to the country level, based on data collected from an online source of BSS information worldwide. A comparative analysis is performed with a focus on Europe, North America and Asia, providing insights on the growth rate of the specific bikesharing market segment. Although the dockless e-BSS has been only within three years of competition with station-based implementations, it shows a rapid integration to the overall technology diffusion trend, while it is more established in Asia and North America in comparison with Europe and launches with larger fleet sizes.
  • 3.1K
  • 27 Oct 2020
Topic Review
Safe Mode (Spacecraft)
Safe mode is an operating mode of a modern unmanned spacecraft during which all non-essential systems are shut down and only essential functions such as thermal management, radio reception and attitude control are active. Safe mode is entered automatically upon the detection of a predefined operating condition or event that may indicate loss of control or damage to the spacecraft. Usually the trigger event is a system failure or detection of operating conditions considered dangerously out of the normal range. Cosmic rays penetrating spacecraft electrical systems can create false signals or commands and thus cause a trigger event. The central processor electronics are especially prone to such events. Another trigger is the lack of a received command within a given time window. Lack of received commands can be caused by hardware failures or mis-programming of the spacecraft, as in the case of the Viking 1 lander. The process of entering safe mode, sometimes referred to as safing, involves a number of immediate physical actions taken to prevent damage or complete loss. Power is removed from non-essential subsystems. Regaining attitude control, if lost, is the highest priority because it is necessary to maintain thermal balance and proper illumination of the solar panels. A tumbling or cartwheeling spacecraft can quickly roast, freeze or exhaust its battery power and be lost forever.
  • 3.1K
  • 02 Nov 2022
Topic Review
Gent (Hyperelastic Model)
The Gent hyperelastic material model is a phenomenological model of rubber elasticity that is based on the concept of limiting chain extensibility. In this model, the strain energy density function is designed such that it has a singularity when the first invariant of the left Cauchy-Green deformation tensor reaches a limiting value [math]\displaystyle{ I_m }[/math]. The strain energy density function for the Gent model is where [math]\displaystyle{ \mu }[/math] is the shear modulus and [math]\displaystyle{ J_m = I_m -3 }[/math]. In the limit where [math]\displaystyle{ I_m \rightarrow \infty }[/math], the Gent model reduces to the Neo-Hookean solid model. This can be seen by expressing the Gent model in the form A Taylor series expansion of [math]\displaystyle{ \ln\left[1 - (I_1-3)x\right] }[/math] around [math]\displaystyle{ x = 0 }[/math] and taking the limit as [math]\displaystyle{ x\rightarrow 0 }[/math] leads to which is the expression for the strain energy density of a Neo-Hookean solid. Several compressible versions of the Gent model have been designed. One such model has the form (the below strain energy function yields a non zero hydrostatic stress at no deformation, refer https://link.springer.com/article/10.1007/s10659-005-4408-x for compressible Gent models). where [math]\displaystyle{ J = \det(\boldsymbol{F}) }[/math], [math]\displaystyle{ \kappa }[/math] is the bulk modulus, and [math]\displaystyle{ \boldsymbol{F} }[/math] is the deformation gradient.
  • 3.1K
  • 21 Nov 2022
Topic Review
Removal of Confederate Monuments and Memorials
For decades in the U.S., there have been isolated incidents of removal of Confederate monuments and memorials, although generally opposed in public opinion polls, and several U.S. States have passed laws over 115 years to hinder or prohibit further removals. In the wake of the Charleston church shooting in June 2015, several municipalities in the United States removed monuments and memorials on public property dedicated to the Confederate States of America. The momentum accelerated in August 2017 after the Unite the Right rally in Charlottesville, Virginia. The removals were driven by the belief that the monuments glorify white supremacy and memorialize a government whose founding principle was the perpetuation and expansion of slavery. Many of those who object to the removals, like President Trump, claim that the artifacts are part of the cultural heritage of the United States. Detractors claim that the vast majority of these Confederate monuments were built during the era of Jim Crow (1877–1954) and the Civil Rights Movement (1954–1968) not as memorials but as a means of intimidating African Americans and reaffirming white supremacy. The monuments have thus become highly politicized; according to Eleanor Harvey, a senior curator at the Smithsonian American Art Museum and a scholar of Civil War history: "If white nationalists and neo-Nazis are now claiming this as part of their heritage, they have essentially co-opted those images and those statues beyond any capacity to neutralize them again". Civil War historian James I. Robertson Jr. referred to the current climate to dismantle or destroy Confederate monuments as an "age of idiocy" and motivated by "elements hell-bent on tearing apart unity that generations of Americans have painfully constructed" and the monuments were not a "Jim Crow signal of defiance." In some Southern states, state law restricts or prohibits altogether the removal or alteration of public Confederate monuments. According to Stan Deaton, senior historian at the Georgia Historical Society, "These laws are the Old South imposing its moral and its political views on us forever more. This is what led to the Civil War, and it still divides us as a country. We have competing visions not only about the future but about the past." As Southern novelist William Faulkner famously put it, in the American South "the past is never dead. It's not even past."
  • 3.1K
  • 30 Nov 2022
Topic Review
Permanent Magnet Synchronous Motor
The most common special features and demands of the PMSMs are described in the appearance of the motor’s failures caused by uncontrolled temperature rise. In addition, heat sources and energy losses, including copper loss, core loss versus motor speed, and output power, are analyzed. Various cooling strategies are listed and discussed. Scope of this review is to develop PMSM for a heavy duty green mobility with the smart light weight materials and with the enhanced cooling approaches.
  • 3.1K
  • 30 Mar 2021
Topic Review
Starch–Mucilage Composite Films
Generally, starch is an edible carbohydrate complex, composed of a linear polymer, amylose (a linear molecule with few branches), and amylopectin (branched-chain molecule). Therefore, the presence of amylose in large quantities provides excellent strength while a high level of amylopectin is responsible for the reduction of the tensile strength during the production of a film. However, starch-based films have limitations in their ability to bear various environmental factors such as temperature, pressure, and natural gases during the handling due to their low strength, flexibility, rigidity, and high hydrophilic nature. To overcome this issue, the combination of starch and mucilage can be used as a binary polymer alternative to improve the mechanical properties of the packaging film. Additionally, the addition of several biopolymers such as cellulose, gum, and gelatin into a starch blend can change the network formation in the film matrix, improving the physicochemical and biological properties of the film. Moreover, mucilage is a water-soluble edible polysaccharide, extensively used in the food industry due to its excellent functional properties (antimicrobial, antioxidant, water-holding, oil holding, and foaming capacity), and diverse industrial applications such as thickening agent, binding agent, emulsifying agent, and suspending agent. Mucilage has a great potential to produce a stable polymeric network that confines the starch granules, which delay the release of amylose in resulting the improvement of the mechanical property of films.
  • 3.1K
  • 17 Aug 2021
Topic Review
Faults in a Photovoltaic System
Photovoltaic systems are prone to breaking down due to harsh conditions. In photovoltaic systems, various types of faults can cause power loss in some way. To improve the reliability of these systems, diagnostic methods using Machine Learning (ML) have been developed. 
  • 3.1K
  • 15 Mar 2024
Topic Review
T Lymphocyte
Exosomes are extracellular vesicles (EV) of endosomal origin (multivesicular bodies, MVB) constitutively released by many different eukaryotic cells by fusion of MVB to the plasma membrane. However, inducible exosome secretion controlled by cell surface receptors is restricted to very few cell types and a limited number of cell surface receptors. Among these, exosome secretion is induced in T lymphocytes and B lymphocytes when stimulated at the immune synapse (IS) via T-cell receptor (TCR) and B-cell receptor (BCR), respectively. IS formation by T and B lymphocytes constitutes a crucial event involved in antigen-specific, cellular and humoral immune responses. Upon IS formation by T and B lymphocytes with antigen-presenting cells (APC) the convergence of MVB towards the microtubule organization center (MTOC), and MTOC polarization to the IS, are involved in polarized exosome secretion at the synaptic cleft. This specialized mechanism provides the immune system with a finely-tuned strategy to increase the specificity and efficiency of crucial secretory effector functions of B and T lymphocytes. Since inducible exosome secretion by antigen-receptors is a critical and unique feature of the immune system this entry considers the study of the traffic events leading to polarized exosome secretion at the IS and some of their biological consequences.
  • 3.1K
  • 29 Oct 2020
Topic Review
Social Networks in Health-Care Industry
The application of social networks in the health domain has become increasingly prevalent. They are web-based technologies which bring together a group of people and health-care providers having in common health-related interests, who share text, image, video and audio contents and interact with each other. This explains the increasing amount of attention paid to this topic by researchers who have investigated a variety of issues dealing with the specific applications in the health-care industry. The aim of this study is to systematize this fragmented body of literature, and provide a comprehensive and multi-level overview of the studies that has been carried out to date on social network uses in healthcare, taking into account the great level of diversity that characterizes this industry. To this end, we conduct a scoping review enabling to identify the major research streams, whose aggregate knowledge are discussed according to three levels of analysis that reflect the viewpoints of the major actors using social networks for health-care purposes, i.e., governments, health-care providers (including health-care organizations and professionals) and social networks’ users (including ill patients and general public). We conclude by proposing directions for future research. 
  • 3.1K
  • 14 Sep 2021
Topic Review
Contributions of Chromatography to the Science Progress
Chromatography was born approximately one century ago and has undergone outstanding technological improvements in innovation, research, and development since then that has made it fundamental to advances in knowledge at different levels, with a relevant impact on the well-being and health of individuals. Chromatography boosted a comprehensive and deeper understanding of the complexity and diversity of human–environment interactions and systems, how these interactions affect our life, and the several societal challenges currently facing, namely those related to the sustainability of our planet and the future generations. From the life sciences, which allowed to identify endogenous metabolites relevant to disease mechanisms, to the OMICS field, nanotechnology, clinical and forensic analysis, drug discovery, environment, and “foodprint”, among others, the wide range of applications of today’s chromatographic techniques is impressive. This is fueled by a great variability of powerful chromatographic instruments currently available, with very high sensitivity, resolution, and identification capacity, that provide a strong basis for an analytical platform able to support the challenging demands of the postgenomic and post COVID-19 eras. 
  • 3.1K
  • 02 Sep 2022
Topic Review
Negative-Sense Single-Stranded RNA Viral Factories
Liquid–liquid phase separation (LLPS) represents a major physiochemical principle to organize intracellular membrane-less structures. Studies with non-segmented negative-sense (NNS) RNA viruses have uncovered a key role of LLPS in the formation of viral inclusion bodies (IBs), sites of viral protein concentration in the cytoplasm of infected cells. These studies further reveal the structural and functional complexity of viral IB factories as liquid-like organelles and sites of viral replication.
  • 3.0K
  • 29 Jan 2021
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