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Topic Review
CNO Cycle
The CNO cycle (for carbon–nitrogen–oxygen; sometimes called Bethe–Weizsäcker cycle after Hans Albrecht Bethe and Carl Friedrich von Weizsäcker) is one of the two known sets of fusion reactions by which stars convert hydrogen to helium, the other being the proton–proton chain reaction (p-p cycle), which is more efficient at the Sun's core temperature. The CNO cycle is hypothesized to be dominant in stars that are more than 1.3 times as massive as the Sun. Unlike the proton-proton reaction, which consumes all its constituents, the CNO cycle is a catalytic cycle. In the CNO cycle, four protons fuse, using carbon, nitrogen, and oxygen isotopes as catalysts, each of which is consumed at one step of the CNO cycle, but re-generated in a later step. The end product is one alpha particle (a stable helium nucleus), two positrons, and two electron neutrinos. There are various alternative paths and catalysts involved in the CNO cycles, all these cycles have the same net result: The positrons will almost instantly annihilate with electrons, releasing energy in the form of gamma rays. The neutrinos escape from the star carrying away some energy. One nucleus goes on to become carbon, nitrogen, and oxygen isotopes through a number of transformations in an endless loop. The proton–proton chain is more prominent in stars the mass of the Sun or less. This difference stems from temperature dependency differences between the two reactions; pp-chain reaction starts at temperatures around 4×106 K (4 megakelvin), making it the dominant energy source in smaller stars. A self-maintaining CNO chain starts at approximately 15×106 K, but its energy output rises much more rapidly with increasing temperatures so that it becomes the dominant source of energy at approximately 17×106 K. The Sun has a core temperature of around 15.7×106 K, and only 1.7% of 4He nuclei produced in the Sun are born in the CNO cycle. The CNO-I process was independently proposed by Carl von Weizsäcker and Hans Bethe in the late 1930s. The first reports of the experimental detection of the neutrinos produced by the CNO cycle in the Sun were published in 2020. This was also the first experimental confirmation that the Sun had a CNO cycle, that the proposed magnitude of the cycle was accurate, and that von Weizsäcker and Bethe were correct.
  • 3.4K
  • 03 Nov 2022
Topic Review
The Use of Green Laser in LiDAR Bathymetry
Bathymetric LiDAR technology is a technology used for simultaneous data acquisition regarding the morphology of the bottom of water reservoirs and the surrounding coastal zone, realized from the air, e.g., by plane or drone. Contrary to the air topographic LiDAR, which uses an infrared wavelength of 1064 nm, bathymetric LiDAR systems additionally use a green wavelength of 532 nm. The green laser can penetrate the water, which makes it possible to measure the depth of shallow water reservoirs, rivers, and coastal sea waters within three Secchi depths.
  • 3.4K
  • 13 Jan 2023
Topic Review
RNA Aptamers
RNA aptamers are becoming increasingly attractive due to their superior properties. 
  • 3.4K
  • 18 Jun 2021
Topic Review
Consumer and Food Product Innovations
New lifestyles, higher incomes and better consumer awareness are increasing the demand for a year-round supply of innovative food products. In past decades, important developments have been achieved in areas related to food and the food industry. This entry shows that factors influencing performance in new product development (NPD) are dynamic and continuously guiding project development. The data obtained by direct involvement of consumers can impact positively successful product development and enhance the company’s financial performance. The study of consumer behaviour and attitudes towards new foods encompasses multiple aspects, such as preference, choice, desire to eat certain foods, buying intentions and frequency of consumption. Additionally, both the consumers’ willingness to purchase and the willingness to pay a premium are important in NPD, launching and success.
  • 3.4K
  • 27 Sep 2020
Topic Review
History of the Portable Document Format (PDF)
The Portable Document Format was created in the early 1990s by Adobe Systems, introduced at the Windows and OS|2 Conference in January 1993 and remained a proprietary format until it was released as an open standard in 2008. Since then, it is under control of International Organization for Standardization Committee of volunteer industry experts. PDF was developed to share documents, including text formatting and inline images, among computer users of disparate platforms who may not have access to mutually-compatible application software.It was created by a research and developement team called Camelot, led by Adobe's co-founder John Warnock. PDF was one among a number of competing formats such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format. In those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows. PDF's adoption in the early days of the format's history was slow. Adobe Acrobat, Adobe's suite for reading and creating PDF files, was not freely available; early versions of PDF had no support for external hyperlinks, reducing its usefulness on the Internet; the larger size of a PDF document compared to plain text required longer download times over the slower modems common at the time; and rendering PDF files was slow on the less powerful machines of the day. Adobe distributed its Adobe Reader (now Acrobat Reader) program free of charge from version 2.0 onwards, and continued supporting the original PDF, which eventually became the de facto standard for fixed-format electronic documents. In 2008 Adobe Systems' PDF Reference 1.7 became ISO 32000:1:2008. Thereafter, further development of PDF (including PDF 2.0) is conducted by ISO's TC 171 SC 2 WG 8 with the participation of Adobe Systems and other subject matter experts.
  • 3.4K
  • 14 Oct 2022
Topic Review
High-Temperature Materials in Ammonia/Hydrogen Gas Turbines
This entry reviews the critical role of material selection and design in ensuring efficient performance and safe operation of gas turbine engines fuelled by ammonia–hydrogen. As these energy fuels present unique combustion characteristics in turbine combustors, the identification of suitable materials becomes imperative. Detailed material characterisation is indispensable for discerning defects and degradation routes in turbine components, thereby illuminating avenues for improvement. With elevated turbine inlet temperatures, there is an augmented susceptibility to thermal degradation and mechanical shortcomings, especially in the high-pressure turbine blade—a critical life-determining component.
  • 3.4K
  • 17 Oct 2023
Topic Review
Biochemical Oxygen Demand
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen (DO) needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. The BOD value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at 20 °C and is often used as a surrogate of the degree of organic pollution of water. BOD reduction is used as a gauge of the effectiveness of wastewater treatment plants. BOD of wastewater effluents is used to indicate the short-term impact on the oxygen levels of the receiving water. BOD analysis is similar in function to chemical oxygen demand (COD) analysis, in that both measure the amount of organic compounds in water. However, COD analysis is less specific, since it measures everything that can be chemically oxidized, rather than just levels of biologically oxidized organic matter.
  • 3.4K
  • 18 Oct 2022
Topic Review
Upāsaka and Upāsikā
Upāsaka (masculine) or Upāsikā (feminine) are from the Sanskrit and Pāli words for "attendant". This is the title of followers of Buddhism (or, historically, of Gautama Buddha) who are not monks, nuns, or novice monastics in a Buddhist order, and who undertake certain vows. In modern times they have a connotation of dedicated piety that is best suggested by terms such as "lay devotee" or "devout lay follower".
  • 3.4K
  • 23 Nov 2022
Topic Review
Monitoring Net Land Take in Europe
Land as an environmental resource has gained increasing importance in European policies. The target of “no net land take” by 2050, set by the 2011 Roadmap to a Resource Efficient Europe, is also reinforced by the Soil Strategy of the European Union for 2030. Net land take evaluates, for a given period, the difference between land take and developed land re-naturalization. Its reduction is only feasible by increasing the re-naturalization of developed land, an intervention undertaken in specific and rare circumstances. Accordingly, reusing or recycling developed land is the only intervention that substantially prevents land take. The following defines the three processes for which monitoring is necessary to evaluate the achievement of this target. Then, the legal framework of the European goal is presented, as well as the interventions that can contribute to its pursuit and the actions already taken by some countries and regions in Europe towards this end.
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  • 13 Jul 2022
Topic Review
Sea Buckthorn
Sea buckthorn is a dioecious and anemophilous plant, the pollination of female blossoms is possible by wind. It withstands well on poor soils and is able to tolerate extreme temperatures ranging from −40 °C to +40 °C. Since it has low requirements on growing conditions, it behaves invasively if it grows in low humid, alluvial gravel, wet landslips, and riverside.
  • 3.4K
  • 20 Oct 2021
Topic Review
GeoAI in Integrated Hydrological and Fluvial Systems Modeling
Geospatial artificial intelligence (GeoAI) allows the harnessing of big and high-dimensional data to better understand the hydrological processes in a particular system. Specifically, GeoAI provides new data analytic tools to the entire data processing cycle, such as sensor data fusion, hydrological modeling, data assimilation, multi-objective scenario optimization, smart decision support, evaluation of climate change impact, construction of early warning systems, and geo-visualization. 
  • 3.4K
  • 22 Jul 2022
Topic Review
Autism
Kanner autism, or classic autism, is a neurodevelopmental disorder characterized by challenges with social communication, and by restricted and repetitive behaviors. It is now considered part of the wider autism spectrum. The term 'autism' was historically used to refer specifically to Kanner autism, which is the convention used in this entry, but it is now more commonly used for the spectrum at large. Parents often notice signs of autism during the first three years of their child's life. These signs often develop gradually, though some autistic children experience regression in their communication and social skills after reaching developmental milestones at a normal pace. Autism has been hypothesized to be associated with a combination of genetic and environmental factors. Risk factors during pregnancy include certain infections, such as rubella, toxins including valproic acid, alcohol, cocaine, pesticides, lead, and air pollution, fetal growth restriction, and autoimmune diseases. Controversies surround other proposed environmental causes; for example, the vaccine hypothesis, which although disproven, continues to hold sway in certain communities. Autism affects information processing in the brain and how nerve cells and their synapses connect and organize; how this occurs is not well understood. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) combines forms of the condition, including high functioning autism (HFA), which was formerly known as Asperger syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS) into the diagnosis of autism spectrum disorder (ASD). Several interventions have been shown to reduce symptoms and improve the ability of autistic people to function and participate independently in the community. Behavioral, psychological, education, and/or skill-building interventions may be used to assist autistic people to learn life skills necessary for living independently, as well as other social, communication, and language skills. Therapy also aims to reduce challenging behaviors and build upon strengths. Some autistic adults are unable to live independently. An autistic culture has developed, with some individuals seeking a cure and others believing autism should be accepted as a difference to be accommodated instead of cured. Globally, autism is estimated to affect 24.8 million people (As of 2015). In the 2000s, the number of autistic people worldwide was estimated at 1–2 per 1,000 people. In the developed countries, about 1.5% of children are diagnosed with ASD (As of 2017), up from 0.7% in 2000 in the United States. It is diagnosed four to five times more often in males than females. The number of people diagnosed has increased considerably since the 1990s, which may be partly due to increased recognition of the condition.
  • 3.4K
  • 28 Sep 2022
Topic Review
Molecular Components of Grape Seeds and Grape Marc
Nutritional interventions may highly contribute to the maintenance or restoration of human health. Grapes (Vitis vinifera) are one of the oldest known beneficial nutritional components of the human diet. Their high polyphenol content has been proven to enhance human health beyond doubt in statistics-based public health studies, especially in the prevention of cardiovascular disease and cancer.
  • 3.4K
  • 28 Sep 2022
Topic Review
Business Process Outsourcing in the Philippines
One of the most dynamic and fastest growing sectors in the Philippines is the information technology–business process outsourcing (IT-BPO) industry. The industry is composed of eight sub-sectors, namely, knowledge process outsourcing and back offices, animation, call centers, software development, game development, engineering design, and medical transcription. The IT-BPO industry plays a major role in the country's growth and development.
  • 3.4K
  • 10 Oct 2022
Topic Review Peer Reviewed
Employment in the 21st Century: Pre- and Post-COVID-19 Changes
In the 21st century, prior to the outbreak of the COVID-19 pandemic, numerous transformations were already underway in the field of employment. However, this unprecedented global health crisis has had a profound influence on employment worldwide, yielding both positive and negative outcomes across various labor aspects. Consequently, while certain effects are anticipated to be temporary, others are likely to instigate enduring changes in employment practices.
  • 3.4K
  • 27 Jul 2023
Topic Review
Forensic Pathology
Forensic pathology is pathology that focuses on determining the cause of death by examining a corpse. A post mortem examination is performed by a medical examiner or forensic pathologist, usually during the investigation of criminal law cases and civil law cases in some jurisdictions. Coroners and medical examiners are also frequently asked to confirm the identity of remains.
  • 3.4K
  • 30 Sep 2022
Topic Review
Bioevaluation of Artemisia judaica L. Plant’s Essential Oil
Artemisia judaica (ArJ) is a Mediterranean aromatic plant used traditionally to treat gastrointestinal ailments, skin diseases, atherosclerosis, and as an immuno-stimulant. Researches validate the curative role of ArJ in the treatment of skin wounds, which is attributed to its antioxidant and anti-inflammatory effects, as well as its high proportion of oxygenated monoterpenes and cinnamate derivatives.
  • 3.4K
  • 21 Feb 2022
Topic Review
Environmental Aspects of the Electric Car
Electric cars (or electric vehicles, EVs) have different environmental impacts compared to conventional internal combustion engine vehicles (ICEVs). While aspects of their production can induce similar, less or alternative environmental impacts, some models produce little or no tailpipe emissions, and some have the potential to reduce dependence on petroleum and greenhouse gas emissions, depending on the source of electricity used to charge them, and health effects from air pollution. Electric motors are significantly more efficient than internal combustion engines and thus, even accounting for typical power plan efficiencies and distribution losses, less energy is required to operate an EV. Producing batteries for electric cars requires additional resources and energy, so they may have a larger environmental footprint from the production phase. EVs also generate different impacts in their operation and maintenance. EVs are typically heavier and could produce more tire, brake, and road dust, but their regenerative braking could reduce brake particulate pollution. EVs are mechanically simpler, which reduces the use and disposal of engine oil.
  • 3.4K
  • 30 Nov 2022
Topic Review
Cassava Value Chain in Thailand
Population growth and urbanization in Thailand has generated negative environmental externalities and the underuse of agricultural materials. Plastics from cassava present an alternative that helps reduce the use of non-biodegradable petroleum-based plastics and can reshape a sustainable cassava value chain. The development of cassava-based bioplastic not only positively contributes to economic aspects but also generates beneficial long-term impacts on social and environmental aspects. Considering cassava supply, bioplastic production, and potential consumer acceptance, the development of bioplastics from cassava in Thailand faces several barriers and is growing slowly, but is needed to drive the sustainable cassava value chain.
  • 3.4K
  • 26 Oct 2023
Topic Review
Concentration Cells Corrosion
In marine environments, microbial attacks on metallic materials result in microbiologically influenced corrosion (MIC), which could cause severe safety accidents and high economic losses. To date, MIC of a number of metallic materials ranging from common steels to corrosion-resistant ferrous alloys has been reported. The MIC process has been explained based on (1) bio-catalyzed oxygen reduction; (2) kinetics alternation of the corrosion process by increasing the mass transport of the reactants and products; (3) production of corrosive substances; and (4) generation of auxiliary cathodic reactants.
  • 3.4K
  • 16 Sep 2022
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