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Topic Review
AT2018cow
Coordinates: 16h 16m 00.2242 s, +22° 16′ 04.890 ″ AT2018cow (ATLAS name: ATLAS18qqn; also known as Supernova 2018cow, SN 2018cow, and "The Cow") was a very powerful astronomical explosion, 10 – 100 times brighter than a normal supernova, spatially coincident with galaxy CGCG 137-068, approximately 200 million ly (60 million pc) distant in the Hercules constellation. It was first detected on 16 June 2018 by the ATLAS-HKO telescope, and had generated significant interest among astronomers throughout the world. Later, on 10 July 2018, and after AT2018cow had significantly faded, astronomers, based on followup studies with the Nordic Optical Telescope (NOT), formally described AT2018cow as SN 2018cow, a type Ib supernova, showing an "unprecedented spectrum for a supernova of this class"; although others, mostly at first but also more recently, have referred to it as a type Ic-BL supernova. An explanation to help better understand the unique features of AT2018cow has been presented.
  • 458
  • 19 Oct 2022
Topic Review
Quantum Reality
Quantum Reality is a 1985 popular science book by physicist Nick Herbert, a member the Fundamental Fysiks Group which was formed to explore the philosophical implications of quantum theory. The book attempts to address the ontology of quantum objects, their attributes, and their interactions, without reliance on advanced mathematical concepts. Herbert discusses the most common interpretations of quantum mechanics and their consequences in turn, highlighting the conceptual advantages and drawbacks of each.
  • 458
  • 30 Nov 2022
Topic Review
Corona
A corona (meaning 'crown' in Latin derived from Ancient Greek 'κορώνη' (korōnè, “garland, wreath”)) is an aura of plasma that surrounds the Sun and other stars. The Sun's corona extends millions of kilometres into outer space and is most easily seen during a total solar eclipse, but it is also observable with a coronagraph. Spectroscopy measurements indicate strong ionization in the corona and a plasma temperature in excess of 1000000 kelvin, much hotter than the surface of the Sun. Light from the corona comes from three primary sources, from the same volume of space. The K-corona (K for kontinuierlich, "continuous" in German) is created by sunlight scattering off free electrons; Doppler broadening of the reflected photospheric absorption lines spreads them so greatly as to completely obscure them, giving the spectral appearance of a continuum with no absorption lines. The F-corona (F for Fraunhofer) is created by sunlight bouncing off dust particles, and is observable because its light contains the Fraunhofer absorption lines that are seen in raw sunlight; the F-corona extends to very high elongation angles from the Sun, where it is called the zodiacal light. The E-corona (E for emission) is due to spectral emission lines produced by ions that are present in the coronal plasma; it may be observed in broad or forbidden or hot spectral emission lines and is the main source of information about the corona's composition.
  • 455
  • 08 Nov 2022
Topic Review
Waveguide-Enhanced Raman Spectroscopy
Photonic chip-based methods for spectroscopy are of considerable interest due to their applicability to compact, low-power devices for the detection of small molecules. Waveguide-enhanced Raman spectroscopy (WERS) has emerged over the past decade as a particularly interesting approach. WERS utilizes the evanescent field of a waveguide to generate Raman scattering from nearby analyte molecules, and then collects the scattered photons back into the waveguide. The large interacting area and strong electromagnetic field provided by the waveguide allow for significant enhancements in Raman signal over conventional approaches.
  • 454
  • 29 Dec 2022
Topic Review
NP04 Experiment
The Deep Underground Neutrino Experiment (DUNE) is a neutrino experiment under construction, with a near detector at Fermilab and a far detector at the Sanford Underground Research Facility that will observe neutrinos produced at Fermilab. An intense beam of trillions of neutrinos from the production facility at Fermilab (in Illinois) will be sent over a distance of 1,300 kilometers (810 mi) with the goal of understanding the role of neutrinos in the universe. More than 1,000 collaborators work on the project. The experiment is designed for a 20-year period of data collection. The primary science objectives of DUNE are The science goals are so compelling that the 2014 Particle Physics Project Prioritization Panel (P5) ranked this as "the highest priority project in its timeframe" (recommendation 13). The importance of these goals has led to proposals for competing projects in other countries, particularly the Hyper-Kamiokande experiment in Japan, scheduled to begin data-taking in 2027. The DUNE project, overseen by Fermilab, has suffered delays to its schedule and growth of cost from less than $2B to $3B, leading to articles in the journals Science and Scientific American described the project as "troubled." As of 2022, the DUNE experiment has a neutrino-beam start-date in the early-2030's, and the project is now phased.
  • 454
  • 19 Oct 2022
Topic Review
Transit of Venus, 2012
The 2012 transit of Venus, when the planet Venus appeared as a small, dark spot passing across the face of the Sun, began at 22:09 UTC on 5 June 2012, and finished at 04:49 UTC on 6 June. Depending on the position of the observer, the exact times varied by up to ±7 minutes. Transits of Venus are among the rarest of predictable celestial phenomena and occur in pairs. Consecutive transits per pair are spaced 8 years apart, and consecutive pairs occur more than a century apart: The previous transit of Venus took place on 8 June 2004 (preceded by transits on 9 December 1874 and 6 December 1882); the next pair of transits will occur on 10–11 December 2117 and in December 2125.
  • 453
  • 28 Nov 2022
Topic Review
Public Utility Holding Company Act of 1935
The Public Utility Holding Company Act of 1935 (PUHCA), also known as the Wheeler-Rayburn Act, was a US federal law giving the Securities and Exchange Commission authority to regulate, license, and break up electric utility holding companies. It limited holding company operations to a single state, thus subjecting them to effective state regulation. It also broke up any holding companies with more than two tiers, forcing divestitures so that each became a single integrated system serving a limited geographic area. Another purpose of the PUHCA was to keep utility holding companies engaged in regulated businesses from also engaging in unregulated businesses. The act was based on the conclusions and recommendations of the 1928-35 Federal Trade Commission investigation of the electric industry. On March 12, 1935, President Franklin D. Roosevelt released a report he commissioned by the National Power Policy Committee. This report became the template for the PUHCA. The political battle over its passage was one of the bitterest of the New Deal, and was followed by eleven years of legal appeals by holding companies led by the Electric Bond and Share Company, which finally completed its breakup in 1961. On August 26, 1935, President Franklin D. Roosevelt signed the bill into law. The Energy Policy Act of 2005 repealed the PUHCA.
  • 452
  • 18 Nov 2022
Topic Review
Minimal Models
In theoretical physics, a minimal model or Virasoro minimal model is a two-dimensional conformal field theory whose spectrum is built from finitely many irreducible representations of the Virasoro algebra. Minimal models have been classified and solved, and found to obey an ADE classification. The term minimal model can also refer to a rational CFT based on an algebra that is larger than the Virasoro algebra, such as a W-algebra.
  • 452
  • 07 Nov 2022
Topic Review
Cardiovascular Disease after Chronic Kidney Disease
Cardiovascular diseases remain the most common cause of morbidity and mortality in chronic kidney disease patients undergoing hemodialysis. Epicardial adipose tissue (EAT), visceral fat depot of the heart, was found to be associated with coronary artery disease in cardiac and non-cardiac patients. Additionally, EAT has been proposed as a novel cardiovascular risk in the general population and in end-stage renal disease patients. It has also been shown that EAT, more than other subcutaneous adipose tissue deposits, acts as a highly active organ producing several bioactive adipokines, and proinflammatory and proatherogenic cytokines. 
  • 451
  • 01 Mar 2022
Topic Review
Brief History of Gel Dosimetry
Advances in radiotherapy technology have significantly improved both dose conformation to tumors and the preservation of healthy tissues, achieving almost real-time feedback by means of high-precision treatments and theranostics. Therefore, developing high-performance systems capable of coping with the challenging requirements of modern ionizing radiation is a key issue to overcome the limitations of traditional dosimeters. In this regard, a deep understanding of the physicochemical basis of gel dosimetry, as one of the most promising tools for the evaluation of 3D high-spatial-resolution dose distributions, represents the starting point for developing new and innovative systems. 
  • 451
  • 02 Nov 2022
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