Luminosity is an absolute measure of radiated electromagnetic power, the radiant power emitted by a light-emitting object. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical object. In SI units, luminosity is measured in joules per watts. In astronomy, values for luminosity are given in the terms of the luminosity of the Sun, L⊙. Luminosity can be given in terms of the astronomical magnitude system: the absolute bolometric magnitude of an object is a logarithmic measure of its total energy emission rate, while absolute magnitude is a logarithmic measure of the luminosity within some specific wavelength range or filter band. In contrast, the term brightness in astronomy is used to refer to an object's apparent brightness: that is, how bright an object appears to an observer. Apparent brightness depends on both the luminosity of the object and the distance between the object and observer, on any absorption of light along the path from object to observer.
Apparent magnitude is a logarithmic measure of apparent brightness. The distance determined by luminosity measures can be somewhat ambiguous, is thus sometimes called the luminosity distance; when not qualified, the term "luminosity" means bolometric luminosity, measured either in the SI units, watts, or in terms of solar luminosities. A bolometer is the instrument used to measure radiant energy over a wide band by absorption and measurement of heating. A star radiates neutrinos, which carry off some energy, contributing to the star's total luminosity; the IAU has defined a nominal solar luminosity of 3.828×1026 W to promote publication of consistent and comparable values in units of the solar luminosity. While bolometers do exist, they cannot be used to measure the apparent brightness of a star because they are insufficiently sensitive across the electromagnetic spectrum and because most wavelengths do not reach the surface of the Earth. In practice bolometric magnitudes are measured by taking measurements at certain wavelengths and constructing a model of the total spectrum, most to match those measurements.
In some cases, the process of estimation is extreme, with luminosities being calculated when less than 1% of the energy output is observed, for example with a hot Wolf-Rayet star observed only in the infrared. Bolometric luminosities can be calculated using a bolometric correction to a luminosity in a particular passband; the term luminosity is used in relation to particular passbands such as a visual luminosity of K-band luminosity. These are not luminosities in the strict sense of an absolute measure of radiated power, but absolute magnitudes defined for a given filter in a photometric system. Several different photometric systems exist; some such as the UBV or Johnson system are defined against photometric standard stars, while others such as the AB system are defined in terms of a spectral flux density. A star's luminosity can be determined from two stellar characteristics: size and effective temperature; the former is represented in terms of solar radii, R⊙, while the latter is represented in kelvins, but in most cases neither can be measured directly.
To determine a star's radius, two other metrics are needed: the star's angular diameter and its distance from Earth. Both can be measured with great accuracy in certain cases, with cool supergiants having large angular diameters, some cool evolved stars having masers in their atmospheres that can be used to measure the parallax using VLBI. However, for most stars the angular diameter or parallax, or both, are far below our ability to measure with any certainty. Since the effective temperature is a number that represents the temperature of a black body that would reproduce the luminosity, it cannot be measured directly, but it can be estimated from the spectrum. An alternative way to measure stellar luminosity is to measure the star's apparent brightness and distance. A third component needed to derive the luminosity is the degree of interstellar extinction, present, a condition that arises because of gas and dust present in the interstellar medium, the Earth's atmosphere, circumstellar matter.
One of astronomy's central challenges in determining a star's luminosity is to derive accurate measurements for each of these components, without which an accurate luminosity figure remains elusive. Extinction can only be measured directly if the actual and observed luminosities are both known, but it can be estimated from the observed colour of a star, using models of the expected level of reddening from the interstellar medium. In the current system of stellar classification, stars are grouped according to temperature, with the massive young and energetic Class O stars boasting temperatures in excess of 30,000 K while the less massive older Class M stars exhibit temperatures less than 3,500 K; because luminosity is proportional to temperature to the fourth power, the large variation in stellar temperatures produces an vaster variation in stellar luminosity. Because the luminosity depends on a high power of the stellar mass, high mass luminous stars have much shorter lifetimes; the most luminous stars are always young stars, no more than a few million years for the most extreme.
In the Hertzsprung–Russell diagram, the x-axis represents temperature or spectral type while the y-axis represents luminosity or magnitude. The vast majority of stars are found along the main sequence with blue Class O stars found at the top left of the chart while red Class M stars fall to the bottom right. Certain stars like Deneb and Betelgeuse are found above and to the
Victor Arthur James Willing was a British painter, noted for his original nude studies. He was a friend and colleague of many notable artists, including Elisabeth Frink, Michael Andrews and Francis Bacon. For his talent and enthusiasm, Willing was dubbed the'spokesman for his generation', he was married to Portuguese feminist artist Paula Rego. Victor Willing was born in Alexandria, the only son of George Willing, professional soldier, his wife Irene Cynthia Tomkins; the first four years of his life were spent there and in Malta. On returning to the UK his father was posted to various parts of southern England including the Isle of Wight and Bordon, Hampshire. Willing's education was in consequence rather disrupted until the family moved permanently to Guildford, Surrey and he was able to attend The Royal Grammar School there, 1940–45. A year was spent at Guildford School of Art while he awaited call-up to National Service which duly followed, 1946–48, he secured a commission as second-lieutenant in the Royal Artillery, serving in Northern Ireland and at Dover.
On release he was accepted by the Slade School of Fine Art, University of London but only to start in 1949, so he returned for a year to Guildford Art School studying sculpture under Willi Soukop. A fellow student and friend there at the time was Elisabeth Frink, he produced two accomplished stone carvings during a female torso and a head. Willing's start at the Slade coincided with William Coldstream's arrival there as Director and Professor. Fellow entrants that year included Michael Andrews, Henry Inlander and James Burr, while Euan Uglow, Craigie Aitchison, Paula Rego and Myles Murphy overlapped subsequently. Other close friends, Keith Sutton and Peter Snow, had started the previous year. Willing was admired by his fellow students for his adventurous talent and intellectual zest and was denoted'spokesman for his generation' by the critic David Sylvester, he was fascinated by one of Francis Bacon's first exhibitions, in 1949, he invited him to talk at the Slade. They subsequently became friends and saw a good deal of each other after Willing left the Slade in 1953.
Another artist who became a long-standing friend was Rodrigo Moynihan and each painted the other's portrait. Willing's portrait of Moynihan is with the Royal College of Art but Moynihan's of Willing was stolen and was, it is thought, destroyed by the thief. Willing took his diploma in 1952 and stayed on for a further year. Of work produced during these student years rather little survives. Four paintings, Head of a Man, Boy on a Tricycle, Head of a Girl and Standing Nude are still extant however and two other'summer compositions', Europa and the Bull and Musicians, his diploma painting Act of Violence is still with University College. In 1951 Willing had married his long-time Guildford girlfriend, Hazel Whittington, they lived first at Shalford near Guildford and, from 1954, in a large maisonette at Lancaster Gate, London, he was able to paint there and in a small studio that he had in Chelsea. In 1955 Erica Brausen of the Hanover Gallery gave him a show, a considerable critical success. Paintings were bought by the Arts Council of Great Britain and by Sir Colin Anderson, a notable supporter of young artists.
A star piece of the show, Reclining Nude, has disappeared from view. There was no catalogue nor, it seems, were the exhibits photographed. Paintings from around this time, which may have been in the exhibition, are Runners and Man Explaining and Winter Machine. Man with a Kitten no longer was published in monochrome. An impressive Man Watching, shown at the ICA in 1953, is believed lost. There were a few portraits: Andrew Forge, Natasha Spender and Lawrence Alloway. By 1956 Willing's marriage was failing and at the end of that year he left home and the country to join Paula Rego in Portugal. Rego's parents were supportive and the two were able to live at the family quinta in Ericeira where they both continued to paint, they were married in 1959 following Willing's divorce from Hazel Whittington. From 1962 they had a base in London, a house in Albert Street, Camden Town which Rego's father, José Figueiroa Rego, had given them. Although many paintings were produced during this period most were painted over.
Survivals include Self Portrait and Standing Nude. Willing was discouraged when the more adventurous Lech, Precarious Drag and Untitled, which relate more to his late work, were viewed unfavourably by a critic friend and he reverted to painting'stodgy nudes'; the year 1966 brought major upsets to his career as an artist. Both his father and his father-in-law died and he saw no option but to take on the management of the latter's business interests in Lisbon. At the same time he was diagnosed as suffering from the early stages of multiple sclerosis. Art took on a lesser role for the next eight years until the Portuguese revolution of 1974 led to the failure of the business and the eventual return of the family – which now included Caroline and Nick Willing – to live permanently in London. Willing had decided that he must now return to his true métier and he rented a room in a disused school in Stepney, east London and began to paint. Alone for long periods, standing only with difficulty, he just sat and looke
The Institute for Marine and Antarctic Studies is a teaching and research institute of the University of Tasmania in Hobart, Tasmania. IMAS was established in 2010 building upon the university's partnership with CSIRO Oceans and Atmosphere and the Australian Antarctic Division in cooperative Antarctic research and Southern Ocean research. Marine geophysicist Prof Mike Coffin was appointed founding Executive Director of IMAS in 2010. Prof Richard Coleman, an oceanographer and cryospheric scientist, was appointed Executive Director of IMAS in July 2015. “To improve understanding of temperate marine, Southern Ocean, Antarctic environments, their resources, their roles in the global climate system through research and outreach”. The Institute takes a multidisciplinary, whole-system approach to research and outreach. IMAS was established with a core research and education capability consisting of significant and internationally recognised expertise in the following foundation themes: Oceans and cryosphere Fisheries and aquaculture Ecology and biodiversityThese programs are linked by three key cross-disciplinary themes to meet integrative and multidisciplinary research goals: Climate change Ocean-Earth system Ocean and Antarctic governance The Australian Research Council's Excellence in Research for Australia initiatives provide a specific benchmark for the core IMAS disciplines of oceanography and fisheries sciences, in 2012 IMAS contributed to the University of Tasmania achieving grade 5 scores in oceanography and geology, a grade 4 score in fisheries sciences.
A new ~69,000 m² building on the Hobart waterfront was completed in 2013, to co-locate IMAS, Australia's Integrated Marine Observing System, the Antarctic Climate and Ecosystems Cooperative Research Centre, the Tasmanian Partnership for Advanced Computing staff and students. The new building, adjacent to CSIRO, will create an exceptional research and educational environment supported by state-of-the-art technology, will serve as a hub for collaborative marine and Antarctic studies; the project is an initiative of the Australian Government as part of the Education Investment Fund. Planning is under way for existing research and educational infrastructure totalling ~4,500 m2 south of Hobart at Taroona to be expanded with new aquaculture and controlled-environment experimental saltwater facilities. Planned new capabilities include temperate/polar ocean simulations, enhanced aquaculture research. Australian Antarctic Division Antarctic Climate and Ecosystems Co-operative Research Centre CSIRO Marine and Atmospheric Research Integrated Marine Observing System Tasmanian Partnership in Advanced Computing National Centre for Marine Conservation and Resource Sustainability at the AMC, Faculty of Science and Technology, University of Tasmania Network of Aquaculture Centres in Asia-Pacific Official Website
Frostburn is a supplemental book to the 3.5 edition of the Dungeons and Dragons fantasy role-playing game. Frostburn provides rules for adventuring in a cold environment as well as an environment known as frostfell, a sort of arctic environment with extreme cold; the book contains information about cold and how it affect characters in the game, as well as various monsters, races and spells that can be found in a Frostfell environment. Frostburn was written by Wolfgang Baur, James Jacobs, George Strayton, published in September 2004. Cover art was by Sam Wood, with interior art by Steve Belledin, Mitch Cotie, Ed Cox, Dennis Crabapple McClain, Steve Ellis, David Griffith, David Hudnut, Dana Knutson, Doug Kovacs, Dan Scott; this book follows two other books and Stormwrack, which deal with specific environments. Black Gate #9
Quantum Psychology: How Brain Software Programs You & Your World is a book written by Robert Anton Wilson published in 1990. It deals with the subject of quantum psychology, an area Wilson wrote about; some consider Quantum Psychology a follow-up to Wilson's earlier volume Prometheus Rising for the presence of practical exercises to demonstrate its concepts at the end of each chapter. It focuses on the metaphysical and epistemological problems of Aristotelean reasoning and its use in everyday language, covering E-Prime and how it addresses many of the semantic "spooks" that common language lets in, it covers psychosomatic healing and a possible explanation for it. Excerpt from Quantum Psychology Vladimir A. Belobrov, Victor Ph. Sharkhov One unorthodox view of the Heisenberg uncertainty principle
Rhadinaea is a genus of snakes of the family Colubridae. The following 22 species are recognized as being valid. Rhadinaea bogertorum C. Myers, 1974 Rhadinaea calligaster Rhadinaea cuneata C. Myers, 1974 Rhadinaea decorata Rhadinaea eduardoi Mata-Silva, Ramírez-Bautista, Berriozabal-Islas & Wilson, 2019 Rhadinaea flavilata Rhadinaea forbesi H. M. Smith, 1942 Rhadinaea fulvivittis Cope, 1875 Rhadinaea gaigeae Bailey, 1937 Rhadinaea hesperia Bailey, 1940 Rhadinaea laureata Rhadinaea macdougalli H. M. Smith & Langebartel, 1949 Rhadinaea marcellae Taylor, 1949 Rhadinaea montana H. M. Smith, 1944 Rhadinaea myersi Rossman, 1965 Rhadinaea nuchalis Gárcia-Vázquez, Pavón-Vázquez, Blancas-Hernández, Blancas-Calva & Centenero-Alcalá, 2018 Rhadinaea omiltemana Rhadinaea pulveriventris Boulenger, 1896 Rhadinaea quinquelineata Cope, 1886 Rhadinaea sargenti Dunn & Bailey, 1939 Rhadinaea taeniata Rhadinaea vermiculaticeps Nota bene: A binomial authority in parentheses indicates that the species was described in a genus other than Rhadinaea.