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2,262,585 | https://en.wikipedia.org/wiki/Software%20package%20metrics | Various software package metrics are used in modular programming. They have been mentioned by Robert Cecil Martin in his 2002 book Agile software development: principles, patterns, and practices.
The term software package here refers to a group of related classes in object-oriented programming.
Number of classes and interfaces: The number of concrete and abstract classes (and interfaces) in the package is an indicator of the extensibility of the package.
Afferent couplings (Ca): The number of classes in other packages that depend upon classes within the package is an indicator of the package's responsibility. Afferent couplings signal inward.
Efferent couplings (Ce): The number of classes in other packages that the classes in a package depend upon is an indicator of the package's dependence on externalities. Efferent couplings signal outward.
Abstractness (A): The ratio of the number of abstract classes (and interfaces) in the analyzed package to the total number of classes in the analyzed package. The range for this metric is 0 to 1, with A=0 indicating a completely concrete package and A=1 indicating a completely abstract package.
Instability (I): The ratio of efferent coupling (Ce) to total coupling (Ce + Ca) such that I = Ce / (Ce + Ca). This metric is an indicator of the package's resilience to change. The range for this metric is 0 to 1, with I=0 indicating a completely stable package and I=1 indicating a completely unstable package.
Distance from the main sequence (D): The perpendicular distance of a package from the idealized line A + I = 1. D is calculated as D = | A + I - 1 |. This metric is an indicator of the package's balance between abstractness and stability. A package squarely on the main sequence is optimally balanced with respect to its abstractness and stability. Ideal packages are either completely abstract and stable (I=0, A=1) or completely concrete and unstable (I=1, A=0). The range for this metric is 0 to 1, with D=0 indicating a package that is coincident with the main sequence and D=1 indicating a package that is as far from the main sequence as possible.
Package dependency cycles: Package dependency cycles are reported along with the hierarchical paths of packages participating in package dependency cycles.
See also
Dependency inversion principle – a method to reduce coupling (Martin 2002:127).
References
External links
OO Metrics tutorial explains package metrics with examples, but gets the Instability index wrong; see page 262 of Martin's Agile Software Development: Principles, Patterns and Practices. Pearson Education. .
Software metrics
Object-oriented programming | Software package metrics | [
"Mathematics",
"Engineering"
] | 558 | [
"Software engineering",
"Quantity",
"Metrics",
"Software metrics"
] |
2,262,599 | https://en.wikipedia.org/wiki/Cage | A cage is an enclosure often made of mesh, bars, or wires, used to confine, contain or protect something or someone. A cage can serve many purposes, including keeping an animal or person in captivity, capturing an animal or person, and displaying an animal at a zoo.
Construction
Since a cage is usually intended to hold living beings, at least some part of its structure must be such as to allow for the entry of light and air. Thus some cages may be made with bars spaced closely together for the intended captive to slip between them, or with windows covered by a mesh of some sort.
Animal cages
Cages often used to confine animals, and some are specially designed to fit a certain species of animal. One or more birds, rodents, reptiles, and even larger animals of certain breeds are sometimes confined in a cage as pets.
Animal cages have been a part of human culture since ancient times. For example, an Ancient Greek vase dated to 490 B.C. depicts a boy holding a possibly domesticated rabbit on his lap, with a cage with an open door in the background. The biblical Book of Jeremiah refers to a tribe being like "cages full of birds", and the Book of Ezekiel describes the capture of a lion in which the captors "pulled him into a cage and brought him to the king of Babylon".
The different laws governing the keeping of animals in captivity generally provide for the size of cages or minimum equipment, depending on the species, whether for transport or for breeding. Swiss legislation, for example, defines minimum absolute internal dimensions for pet cages, but the Swiss Animal Protection organization (PSA) states that even if these dimensions comply with the law, they are far from being in line with the needs of species. It is therefore necessary in practice to provide a much higher vital space to ensure the well-being of the occupants.
Animal protection associations have often argued for improving transport conditions in cages and for bans on battery cages, especially for egg-laying hens. The European legislation is constantly changing, but consumer behavior also influences breeding conditions.
Trapping
Cages also serve as a trapping tool. This is a common and illegal purpose of the cage, as poaching is illegal itself. These type of cages are used to trap an animal, or hold them for a certain period of time. U.S. President Theodore Roosevelt used a cage himself to capture a bear, as the cage serves a purpose for capturing large animals.
Human cages
Punishment
In history, prisoners were sometimes kept in a cage. During the Vietnam War they were referred to as "tiger cages". Captives would sometimes be chained up inside into uncomfortable positions to intensify suffering. In medieval England, King Edward punished Robert the Bruce by having two of his female supporters encaged in public.
Safety
Safety cage, in automobile safety
Roll cage, a frame built in or around the cab of a vehicle
Shark-proof cage, used to protect divers
Entertainment
Cages are used in various forms of entertainment to create excitement from the sense that the entertainers are trapped in the cage. For example, cage dancing "refers to a scantily-clad feminine dancer, perhaps wearing a mini-skirt or hot- pants, and (supposedly) trapped inside of a hanging bird cage". Cage fighting involves two combatants, usually engaging in mixed martial arts, inside a cage-like structure, and "conjures up the image of two combatants trapped in a cage, trading vicious blows as the audience bays for blood". In Australia, a ban on the use of "cage-like enclosures" at such events was lifted in 2014. Steel cages are also one of the oldest form of enclosures used in professional wrestling. The first "steel cage match" of any kind took place on June 25, 1937 in Atlanta, Georgia. This match took place in a ring surrounded by chicken wire, in order to keep the athletes inside, and prevent any potential interference.
Homes
Engineering
Rebar cages used in reinforced concrete
Cage (bearing) – a component of a rolling-element bearing
Gabion – a cage filled with coarse gravel or rock for use in civil engineering, road building, military applications and landscaping
Mine cage – similar to an elevator, for a shaft mine
Cage, a separated enclosure in a computer colocation centre
Faraday cage – an enclosure used to block electric fields
Other uses
Batting cage – an enclosure for baseball batting practice
Bottle cage – a bicycle bottle holder
Cage crinoline – a type of crinoline petticoat
Cage trolley - used for transporting goods
Fruit cage - used to protect fruit bushes from been eaten by birds
See also
Aquarium
Box
Formicarium
Gestation crate
Iron maiden – an iron cabinet putative torture device
Jungle gym – inspired by monkeys shaking the bars of a cage
Pen (enclosure)
Terrarium
Vivarium
References
External links
Containers
Buildings and structures used to confine animals
Metalworking
Building materials
Steel | Cage | [
"Physics",
"Engineering"
] | 985 | [
"Building engineering",
"Construction",
"Materials",
"Building materials",
"Matter",
"Architecture"
] |
2,262,820 | https://en.wikipedia.org/wiki/Sun%20Blade%20%28workstation%29 | The Sun Blade series is a computer workstation line based on the UltraSPARC microprocessor family, developed and sold by Sun Microsystems from 2000 to 2006. The range replaced the earlier Sun Ultra workstation series.
The Sun Blade 1000, introduced in October 2000, was the first system to use Fireplane as the interconnect between its single or dual processors and the I/O subsystem, a few months ahead of its use in the new Sun Fire server product line.
The 1500/2500 series came in two variants, the earlier "red" series, and the later "silver" series. The "silver" series were enhanced versions of the "red" series - a faster CPU being the key differentiator.
The Sun Blade series was supplanted by the Sun Java Workstation line in 2004.
The product line's name was not a reference to "blade server" systems, a term not yet in common use in 2000. In 2006, Sun did introduce an unrelated "Sun Blade" blade server product line.
Models
External links
Oracle Legacy Product Documentation: Workstations
Sun System Handbook, v2.1
Sun workstations
SPARC microprocessor products | Sun Blade (workstation) | [
"Technology"
] | 246 | [
"Computing stubs",
"Computer hardware stubs"
] |
2,262,935 | https://en.wikipedia.org/wiki/Reissert%20indole%20synthesis | The Reissert indole synthesis is a series of chemical reactions designed to synthesize indole or substituted-indoles (4 and 5) from ortho-nitrotoluene 1 and diethyl oxalate 2.
Potassium ethoxide has been shown to give better results than sodium ethoxide.
Reaction mechanism
The first step of the synthesis is the condensation of o-nitrotoluene 1 with a diethyl oxalate 2 to give ethyl o-nitrophenylpyruvate 3. The reductive cyclization of 3 with zinc in acetic acid gives indole-2-carboxylic acid 4. If desired, 4 can be decarboxylated with heat to give indole 5.
Variations
Butin modification
In an intramolecular version of the Reissert reaction, a furan ring-opening provides the carbonyl necessary for cyclization to form an indole. A ketone side chain is present in the final product, allowing further modifications.
See also
Leimgruber-Batcho indole synthesis
References
Indole forming reactions
Name reactions | Reissert indole synthesis | [
"Chemistry"
] | 235 | [
"Name reactions",
"Ring forming reactions",
"Organic reactions"
] |
2,263,034 | https://en.wikipedia.org/wiki/American%20Solar%20Challenge | The American Solar Challenge (ASC), previously known as the North American Solar Challenge and Sunrayce, is a solar car race across the United States. In the race, teams from colleges and universities throughout North America design, build, test, and race solar-powered vehicles in a long distance road rally-style event. ASC is a test of teamwork, engineering skill, and endurance that stretches across thousands of miles of public roads.
The competition occurs every two years in the summer of even years. ASC 2020 was postponed until 2021 due to the COVID-19 pandemic.
Format and organization
Rules
Race consists of a series of timed stages between predetermined locations; all teams begin and end each stage in the same location
The team with the lowest overall elapsed time wins
The total area of all solar cells and related reflectors, etc. must not exceed 6 square meters
When the vehicle has stopped, the solar array may be reoriented toward the sun for charging batteries
Strict specifications and engineering scrutiny process is provided for vehicle configuration, safety requirements, and other standards
Previous races have divided teams into open and stock classes based on levels of solar cell and battery technologies.
The Formula Sun Grand Prix track race serves as a qualifier for the more prestigious ASC.
History
Originally called Sunrayce USA, the first race was organized and sponsored by General Motors in 1990 in an effort to promote automotive engineering and solar energy among college students. At the time, GM had just won the inaugural World Solar Challenge in Australia in 1987; rather than continue actively racing, it instead opted to sponsor collegiate events.
Subsequent races were held in 1993, 1995, 1997 and 1999 under the name Sunrayce [year] (e.g. Sunrayce 93). In 2001, the race was renamed American Solar Challenge and was sponsored by the United States Department of Energy and the National Renewable Energy Laboratory. Beginning in 2005, its name changed again to North American Solar Challenge, in order to reflect the border crossing into Canada and the addition of co-sponsor Natural Resources Canada. The name was changed back to ASC in 2010.
After the 2005 race, the U.S. Department of Energy discontinued its sponsorship, resulting in no scheduled race for 2007. Sponsorship was taken over for NASC 2008 by Toyota. The American Solar Challenge is now governed by the Innovators Educational Foundation.
1990
The original, Sunrayce USA route started at Disney World in Orlando, Florida and ended at the General Motors Technical Center in Warren, Michigan. The winner of the first race was the University of Michigan Solar Car Team's Sunrunner, with an average speed of , followed by Western Washington University's Viking XX.
Overall Standings
1993
Sunrayce 93 was held June 20–26, 1993. The race route covered over starting in Arlington, TX and ending in Minneapolis, Minnesota. The first place car was Maize & Blue from the University of Michigan followed by the Intrepid from Cal Poly Pomona.
Overall Standings
1995
Sunrayce 95 ran along a route from Indianapolis, Indiana to Golden, Colorado. Massachusetts Institute of Technology's Manta won the race with an average speed of , followed by the University of Minnesota's Aurora II just 18 minutes behind.
Overall Standings
1997
Sunrayce 1997 followed a familiar route from Indianapolis, Indiana to a finish line in Colorado Springs, Colorado.
California State University-Los Angeles's Solar Eagle III won the nine-day Sunrayce 97. Solar Eagle III averaged , followed by MIT's Manta GT in second place.
Overall Standings
1999
Sunrayce 99, running from Washington, D.C., to Orlando, Florida, was notable for its lack of sunshine. The University of Missouri-Rolla's Solar Miner II won the race with an average speed of . The car from Queen's University placed second.
Overall Standings
2001
In 2001, the race changed its name to the American Solar Challenge and followed a new route from Chicago, Illinois to Claremont, California along much of the old U.S. Route 66. The University of Michigan won the overall race and the Open Class with a total elapsed time of 56 hours, 10 minutes, and 46 seconds, followed by the University of Missouri-Rolla. The University of Arizona team won the Stock Class event.
Overall Standings
2003
The 2003 American Solar Challenge also followed U.S. Route 66. Solar Miner IV from the University of Missouri-Rolla won the race overall, as well as the Open Class, followed by the University of Minnesota's Borealis II. The Stock Class was won by the Prairie Fire GT from North Dakota State University.
Overall Standings
2005
The 2005 race, renamed the North American Solar Challenge, was both the longest and most hotly contested race in the history of the event. The route covered , taking the teams from Austin, Texas in the United States to Calgary, Alberta in Canada. The race was won by the Momentum from the University of Michigan with an average speed of . The University of Minnesota's Borealis III followed in second place less than 12 minutes behind, with an average speed of . The lead teams often drove (the maximum allowed), but were slowed by rain in Kansas and headwinds in Canada. Stanford University's Solstice won the Stock Class, followed in second place by the Beam Machine from The University of California, Berkeley.
Overall Standings
2008
The 2008 North American Solar Challenge took place on July 13–22, 2008, mostly along the 2005 route from Dallas, Texas to Calgary, Alberta. The University of Michigan's Continuum won the race with a total elapsed time of 51 hours, 41 minutes, and 53 seconds, marking that school's fifth victory. Ra 7 from Principia College followed in second place.
As many of the top cars were bumping up against the race speed limit in the 2005 event, race rules were changed for 2008 order to improve safety and limit performance. Open class cars are now only allowed 6 square meters of active cell area, and upright seating is required for both open and stock class cars. The changes were carried over from the 2007 World Solar Challenge.
Overall Standings
2010
The 2010 race, renamed the American Solar Challenge, ran June 20–26, 2010. The University of Michigan finished in first place, followed by the University of Minnesota's Centaurus II in 2nd place and team Bochum from Germany in 3rd. The race route was entirely within the United States for the first time since 2003.
Overall Standings
2012
Only four teams finished the 2012 American Solar Challenge, a 1600-mile race from Rochester, NY to St. Paul, MN, under solar power alone. The University of Michigan's Quantum won the overall competition, over 10 hours ahead of the 2nd place team. The 2nd, 3rd, and 4th place teams were only an hour apart from each other. In order: Iowa State University's Hyperion, Principia College's Ra7s, and the University of California, Berkeley's Impulse.
Overall Standings
2014
The 2014 American Solar Challenge reverted to the familiar south–north race route starting in Austin, Texas, and finishing in Minneapolis, Minnesota. The University of Michigan's Quantum once again took 1st place, followed by University of Minnesota's Centaurus III. Both teams had brought back their cars from the 2012 event.
Overall Standings
2016
The 2016 American Solar Challenge ran from Brecksville, Ohio to Hot Springs, South Dakota from July 30 to August 6, 2016. ASC partnered with the National Park Service, and the route included stages and checkpoints at 9 national parks, historic sites, or partner properties throughout the Midwest. The University of Michigan's Aurum won the overall competition, by a margin of over 11 hours. In second place was the Dunwoody College of Technology team in partnership with Zurich University of Applied Sciences. The University of Minnesota's Eos I made history as the first Cruiser Class vehicle to ever compete in ASC.
Overall Standings
2018
The 2018 American Solar Challenge ran from Omaha, Nebraska to Bend, Oregon from July 14 to July 22, 2018. ASC partnered with the National Park Service, and the route included stages and checkpoints at historic sights along the Oregon Trail. It was the first to include a Cruiser Class, featuring more practical multi-occupant Solar Vehicles. Western Sydney University's car UNLIMITED 2.0 won the Challenger class competition by a margin of 16 minutes—the closest finish in ASC history—as The University of Michigan failed to defend their title with their car Novum. The University of Bologna won the inaugural Cruiser class competition, and the University of Waterloo became the first Canadian Cruiser Class vehicle to ever compete in ASC.
2020
The 2020 American Solar Challenge was postponed due to the COVID-19 pandemic. It was held in 2021, with the starting point at Independence, Missouri and the end point at Las Vegas, New Mexico from August 4 to August 7. The team from the Massachusetts Institute of Technology took first place in the single-occupant class with Nimbus, with approximately 143 miles more in distance covered compared to second place, held by the University of Kentucky team. Appalachian State took first place in the multi-occupant vehicle class.
2022
The 2022 American Solar Challenge ran from Independence, Missouri to Twin Falls, Idaho from July 9 to July 16, 2022. Similar to the 2018 race, ASC partnered with the National Park Service, and the route traversed through historic sites and landmarks along the Oregon Trail. The team from the Massachusetts Institute of Technology took first place in the single-occupant class with their champion vehicle from the previous race, Nimbus. They finished the race with just over 73 miles more than second place finisher Principia College. The winner of the Cruiser class was the University of Minnesota, with Appalachian State University coming in second place.
2024
The Elecktrek American Solar Challenge 2024 ran from Nashville, Tennessee to Casper, Wyoming from July 20 to July 27, 2024. Similar to the previous competitions, ASC partnered with the National Park Service this time following several National Historic Trails and finishing at the National Historic Trails Interpretive Center.
The Single Occupant Vehicle Class was won by the University of Michigan Solar Car Team with 2095.5 miles traveled during the event while the Multi-Occupant Vehicle Class was on by the team from Polytechnique Montréal with a score of 73.86.
See also
Solar car racing
List of solar car teams
List of prototype solar-powered cars
Other solar vehicle challenges
Formula Sun Grand Prix
World Solar Challenge, the biennial World Championship solar car race held in Australia
South African Solar Challenge, a biennial South African event that was first held in 2008
The Solar Car Challenge, an annual event for High School students from the U.S. and (to a lesser extent) other parts of the world, first held in 1995
References
External links
American Solar Challenge
Formula Sun Grand Prix
Video coverage of the race from 1990, 1993, and 1997
Solar car races
Photovoltaics
Science competitions | American Solar Challenge | [
"Technology"
] | 2,250 | [
"Science and technology awards",
"Science competitions"
] |
2,263,098 | https://en.wikipedia.org/wiki/Fellow%20of%20the%20American%20Institute%20of%20Architects | Fellow of the American Institute of Architects (FAIA) is a postnominal title or membership, designating an individual who has been named a fellow of the American Institute of Architects (AIA).
Fellowship is bestowed by the institute on AIA-member architects who have made outstanding contributions to the profession through design excellence, contributions in the field of architectural education, or to the advancement of the profession. In 2014, fewer than 3,200 of the more than 80,000 AIA members were fellows. Honorary Fellowship (Hon. FAIA) is awarded to foreign (non-U.S. citizen) architects, and to non-architects who have made substantial contributions to the field of architecture or to the institute.
Categories
Fellowship is awarded in one of six categories:
Design
Practice management or technical advancement
Leadership
Public service
Volunteer work or service to society
Education and research
History
Membership in the American Institute of Architects was originally divided into two categories, Professional and Associate, with the former largely corresponding to the later title of Fellow. This title was first proposed in 1864 by Calvert Vaux, and by at least 1867 was in common use. Earlier Professional members, including several of the founders, began using the title at this time, and prior Professional members are now considered Fellows. During this period, the title was considered a senior rather than honorary title. In 1889, the AIA was merged with the Western Association of Architects (WAA), which had designated all of its members Fellows. Upon the merger, WAA members kept their title and all existing AIA members were raised to Fellowship. Beginning in 1890, Fellowship was the primary form of membership in the AIA, in addition to "Honorary and Corresponding" members, who, as in the present, were non-architects or foreign nationals.
In 1898, the AIA returned to a two-tier membership system of Fellows and Associates, with significant requirements for election to Fellowship and the final decision left to the AIA Board of Directors. It is from this point forward that designation as a Fellow is considered a formal honor. Beginning in 1922, Fellows were elected by a Jury of Fellows, then nominated by the President, and now by the Secretary. In 1952 the present College of Fellows was established to formally represent Fellows within the larger organization.
Notable Fellows
Architects recognized with FAIA include:
See also
AIA Gold Medal
References
External links
AIA College of Fellows | Fellow of the American Institute of Architects | [
"Engineering"
] | 483 | [
"Architecture stubs",
"Architecture"
] |
2,263,201 | https://en.wikipedia.org/wiki/Stephen%20H.%20Webb | Stephen H. Webb (March 13, 1961 – March 5, 2016) was a theologian and philosopher of religion.
Webb graduated from Wabash College in 1983, earned his Ph.D. at the University of Chicago, and taught at Wabash College as Professor of Religion and Philosophy from 1988 to 2012. (He was on leave from Wabash College during 2012-13, and retired early to pursue writing opportunities full-time.) Born in 1961 and reared in Indianapolis, Indiana, he grew up at Englewood Christian Church, an evangelical church in the Restoration Movement. He recounts his experiences there in Taking Religion to School (Brazos Press, 2000) and in an essay, "Recalling: A Theologian Remembers His Church," in Falling Toward Grace: Images of Religion and Culture from the Heartland, ed. Kent Calder and Susan Neville (Indiana University Press, 1998). He joined the Disciples of Christ during graduate school but soon became disenchanted with their theological direction. He was briefly a Lutheran, and on Easter Sunday, 2007, he officially became a member of the Catholic Church, in which he remained for the rest of his life.
Views on vegetarianism and animal rights
He was known for his scholarship and journalism on animals, vegetarianism, and diet. He co-founded the Christian Vegetarian Association, but was removed from his position as co-chairman in 2006 after writing several articles in which he admitted to eating meat occasionally, while promoting vegetarianism. He defended the value of animals by reaffirming traditional notions of human uniqueness and human responsibility for nature. Many animal rights arguments are influenced by a leveling of the differences between humans and animals as well as a leveling of the differences between God and the world. This vision of a non-dogmatic and non-legalistic vegetarianism linked to traditional biblical principles rather than the pantheism of the New Age movement or the abdication of human uniqueness entailed in animal rights legislation has been controversial in both theological and philosophical circles. For an example of his work, see his essays, "Theology from the Pet Side Up: A Christian Agenda for NOT Saving the World" and "Against the Gourmands: In Praise of Fast Food as a Form of Fasting," both published in the online journal The Other Journal.
Webb's critique of what he calls the "animal eliminationist" wing of the animal rights movement was presented at the 2008 American Academy of Religion conference in Chicago.
Several books have extensively analyzed and criticized his position, including Laura Hobgood-Oster, Holy Dogs and Asses (University of Illinois Press, 2008) and Stephen M. Vantassel, Dominion over Wildlife? (Resource Publications, 2009). The Encyclopedia of Christianity, ed. John Bowden (Oxford University Press, 2005) lists him as one of the leaders of the animal theology movement (p. 52).
Political views
Later in his career, Webb turned his attention to politics, culture, popular culture, and liberal advocacy. Within this field, Webb generated positive and negative reviews with his book American Providence (Continuum, 2004) in which he defended the idea that the doctrine of providence has been a crucial ingredient in American history and American identity. Providential interpretations of American national aspirations went into decline after the Vietnam War, but with President Bush's openness regarding the role of faith in his presidency, providence has returned to the public square. Webb argued that even anti-Americanism is dependent upon providential logic, because conspiracy theories about how evil America is grant America a special role in world history. He also argued that the future belongs to the triad of capitalism, democracy, and various forms of evangelical Christianity, not limited to explicitly evangelical churches. One of his controversial essays on politics is “On the True Globalism and the False, or Why Christians Should Not Worry So Much about American Imperialism,” in Anxious About Empire: Theological Essays on the New Global Realities, ed. Wes Avram (Grand Rapids: Brazos Press, 2004), pp. 119–128. William T. Cavanaugh has criticized Webb's connection of providence and politics.
Books on theology and sound
Webb is also known for his work in what he called theo-acoustics, or a theology of sound. He wrote a comprehensive history of Christianity and sound in The Divine Voice: Christian Proclamation and the Theology of Sound (Brazos Press, 2004). This book, which was named the Religious Communication Association's Book of the Year for 2005 and a Christianity Today Top Ten Book of 2004, is divided into three parts. The first part surveys the biblical tradition on the importance of the human voice as a medium of revelation in the Bible. The second part focuses on the Protestant Reformation as the revival of that tradition. The third part discusses the transformations of that tradition in contemporary culture, which is increasingly oriented toward the visual over the auditory. He also discusses the role of deafness in Christian history and various theological debates over the question of how God created the world through sound. In this discussion he reveals his battle with hearing loss and how that has affected his theological work. He ends that book talking about wordless music and the decline of authentic vocalization in rock and roll, so it was a natural progression to turn to Bob Dylan in his next book, Dylan Redeemed: From Highway 61 to Saved (Continuum, 2006). This book, which has been written about in many Dylan blogs, is a reassessment of Bob Dylan's musical career that focuses on Dylan's mid-life conversion to Christianity.
Books on literature
Webb wrote about C. S. Lewis in The Chronicles of Narnia and Philosophy (ed. by Jerry Walls, Open Court Publishing, 2005), Indiana small town basketball in Basketball and Philosophy (University of Kentucky Press, 2007), and eschatology and politics in The Oxford Handbook of Eschatology (Oxford University Press, 2008). He also wrote the commendation for John Updike for the Presentation of the Christianity and Literature Lifetime Achievement Award at the Modern Languages Association Meeting in December, 2006. His remarks, and Updike's generous response, appear in Christianity and Literature, vol. 56, No. 3 (Spring 2007), pp. 481–485, and Updike's response was subsequently published as the last essay in Updike's Higher Gossip (Knopf, 2011), pp. 479–481. Webb was also a frequent blogger and contributor to First Things and Books & Culture.
Lectures
He delivered invited lectures at Aberdeen University, Calvin College, Wheaton College, Bangor Seminary, Maine, Virginia Theological Seminary, Arizona State University, Pepperdine University, Butler University, Brigham Young University, Hartford Seminary, Creighton University, Wilfrid Laurier University, Hope College, Kalamazoo College, Purdue University, Elmhurst College, and Loyola University in Baltimore. He gave the Truman Madsen Lecture at Brigham Young University in 2012, the first Inaugural "Animals and the Kingdom" lecture at Calvin College in 2008, the Kretzmann Lecture at Valparaiso University in 2008, and the Womack Lecture at Methodist University in 2014.
Other books
He also wrote many essays on the intersection of rhetoric and religion, including "Reviving the Rhetorical Heritage of Protestant Theology," in A Companion to Rhetoric and Rhetorical Criticism, ed. Walter Jost and Wendy Olmsted (Oxford: Blackwell Publishing, 2004): 409-24, and "Theological Reflections on the Hyperbolic Imagination," in Rhetorical Invention and Religious Inquiry, ed. Walter Jost and Wendy Olmstead (New Haven: Yale University Press, 2000). The SAGE Handbook of Rhetorical Studies, ed. Andrea Lunsford (2008) lists him as a leader in the field of religious rhetoric (see p. 555).
Webb wrote a book critical of Darwinism, The Dome of Eden: A New Solution to the Problem of Creation and Evolution (Cascades, 2010). His book Jesus Christ, Eternal God: Heavenly Flesh and the Metaphysics of Matter (Oxford University Press, 2012), engages with Mormon theology in order to develop a revisionist account of Chalcedonian christology that seeks to redeem and appropriate monophysitism for modern theology. His essay in defense of Mormonism as a legitimate form of Christianity, "Mormonism Obsessed with Christ," appeared in First Things (February 2012) and was the topic of much discussion, including an opinion piece published in the Salt Lake Tribune co-authored by Mormon philosopher David L. Paulsen.
Personal life
Stephen Webb lived in Brownsburg, Indiana with his wife, Diane Timmerman, who is a Professor of Theatre at Butler University, and their five children. He died by suicide on March 5, 2016 as the culmination of a long struggle with depression.
Bibliography
Catholic and Mormon: A Theological Conversation (Oxford, 2015)
Mormon Christianity: What Non-Mormon Christians Can Learn from the Latter-day Saints (Oxford, 2013)
Jesus Christ, Eternal God: Heavenly Flesh and the Metaphysics of Matter (Oxford, 2012)
Dome of Eden: A New Solution to the Problem of Creation and Evolution (Cascades, 2010)
Dylan Redeemed: From Highway 61 to Saved (Continuum, 2006; re-issued by Wipf & Stock in 2012)
The Divine Voice: Christian Proclamation and the Theology of Sound (Brazos Press, 2004)
American Providence: A Nation with a Mission (Continuum, 2004)
Good Eating: The Bible, Diet and the Proper Love of Animals (Grand Rapids: Brazos Press/Baker, 2001)
Taking Religion to School: Christian Theology and Secular Education.(Brazos Press, 2000, 253 pages with notes)
On God and Dogs: A Christian Theology of Compassion for Animals (With a Foreword by Andrew Linzey) (Oxford University Press, 1998)
The Gifting God: A Trinitarian Ethics of Excess (Oxford University Press, 1996)
Blessed Excess: Religion and the Hyperbolic Imagination (SUNY Series in Rhetoric and Theology) (Albany: SUNY Press, 1993)
Refiguring Theology: The Rhetoric of Karl Barth (SUNY, 1991)
References
External links
For an article on Intelligent Design that received numerous critical posts, see
http://www.christianitytoday.com/ct/2008/marchweb-only/113-42.0.html
For an essay about dogs that was commissioned by the National Humane Society, see
https://web.archive.org/web/20081225192831/http://www.hsus.org/religion/francis-files-stories/remembering_marie_speaking.html
For two articles about liberal arts education by Webb from LiberalArtsOnline, see
http://www.liberalarts.wabash.edu/lao-2-11-size-of-a-college and http://www.liberalarts.wabash.edu/lao-2-9-preaching-liberal-arts
For a review of American Providence in the journal First Things, see
http://www.firstthings.com/article.php3?id_article=145&var_recherche=Stephen+H.+Webb
For an article about Dylan, see
http://www.firstthings.com/article.php3?id_article=5336
For a review of Dylan Redeemed, see
https://web.archive.org/web/20080225224148/http://spacemonkeylab.com/dylandaily/blog/archives/00000475.php
For an interview of Webb on Dylan in the UK's The Guardian, see
http://education.guardian.co.uk/egweekly/story/0,,2217255,00.html
For the Mormon community's interest in Prof. Webb's reflections on Mormonism, see from the Mormon Times
http://www.mormontimes.com/studies_doctrine/?id=3127
Christian writers
1961 births
2016 deaths
20th-century American Roman Catholic theologians
21st-century American Roman Catholic theologians
Critics of animal rights
Mormon studies scholars
Theistic evolutionists
University of Chicago alumni
Wabash College alumni
Wabash College faculty
Suicides in Indiana | Stephen H. Webb | [
"Biology"
] | 2,516 | [
"Non-Darwinian evolution",
"Theistic evolutionists",
"Biology theories"
] |
2,263,246 | https://en.wikipedia.org/wiki/Telluric%20acid | Telluric acid, or more accurately orthotelluric acid, is a chemical compound with the formula , often written as . It is a white crystalline solid made up of octahedral molecules which persist in aqueous solution. In the solid state, there are two forms, rhombohedral and monoclinic, and both contain octahedral molecules, containing one hexavalent tellurium (Te) atom in the +6 oxidation state, attached to six hydroxyl (–OH) groups, thus, it can be called tellurium(VI) hydroxide.
Telluric acid is a weak acid which is dibasic, forming tellurate salts with strong bases and hydrogen tellurate salts with weaker bases or upon hydrolysis of tellurates in water. It is used as tellurium-source in the synthesis of oxidation catalysts.
Preparation
Telluric acid is formed by the oxidation of tellurium or tellurium dioxide with a powerful oxidising agent such as hydrogen peroxide, chromium trioxide or sodium peroxide.
Crystallization of telluric acid solutions below 10 °C gives telluric acid tetrahydrate .
It is an oxidising agent, as shown by the electrode potential for the reaction below, although it is kinetically slow in its oxidations.
, Eo = +1.02 V
Chlorine, by comparison, is +1.36 V and selenous acid is +0.74 V in oxidizing conditions.
Properties and reactions
The anhydrous acid is stable in air at 100 °C but above this it dehydrates to form polymetatelluric acid, a white hygroscopic powder (approximate composition ), and allotelluric acid, an acid syrup of unknown structure (approximate composition ).
Typical salts of the acid contains the anions and . The presence of the tellurate ion has been confirmed in the solid state structure of .
Strong heating at over 300 °C produces the α crystalline modification of tellurium trioxide, α-.
Reaction with diazomethane gives the hexamethyl ester, .
Telluric acid and its salts mostly contain hexacoordinate tellurium. This is true even for salts such as magnesium tellurate, , which is isostructural with magnesium molybdate and contains octahedra.
Other forms of telluric acid
Metatelluric acid, , the tellurium analogue of sulfuric acid, , is unknown. Allotelluric acid of approximate composition , is not well characterised and may be a mixture of and .
Other tellurium acids
Tellurous acid , containing tellurium in its +4 oxidation state, is known but not well characterised.
Hydrogen telluride is an unstable gas that forms hydrotelluric acid upon addition to water.
References
Hydroxides
Tellurates
Oxidizing acids
Chalcogen oxoacids | Telluric acid | [
"Chemistry"
] | 619 | [
"Acids",
"Hydroxides",
"Oxidizing agents",
"Oxidizing acids",
"Bases (chemistry)"
] |
2,263,256 | https://en.wikipedia.org/wiki/International%20Water%20Management%20Institute | The International Water Management Institute (IWMI) is a non-profit international water management research organisation under the CGIAR with its headquarters in Colombo, Sri Lanka, and offices across Africa and Asia. Research at the Institute focuses on improving how water and land resources are managed, with the aim of underpinning food security and reducing poverty while safeguarding the environment.
Its research focuses on: water availability and access, including adaptation to climate change; how water is used and how it can be used more productively; water quality and its relationship to health and the environment; and how societies govern their water resources. In 2012, IWMI was awarded the prestigious Stockholm Water Prize Laureate by Stockholm International Water Institute for its pioneering research, which has helped to improve agricultural water management, enhance food security, protect environmental health and alleviate poverty in developing countries.
IWMI is a member of CGIAR, a global research partnership that unites organizations engaged in research for sustainable development, and leads the CGIAR Research Program on Water, Land and Ecosystems. IWMI is also a partner in the CGIAR Research Programs on: Aquatic Agricultural Systems (AAS); Climate Change, Agriculture and Food Security (CCAFS); Dryland Systems; and Integrated Systems for the Humid Tropics.
History
Early focus on irrigation
The institute was founded under the name International Irrigation Management Institute (IIMI) in 1985 by the Ford Foundation and the Government of Sri Lanka, supported by the Consultative Group on International Agricultural Research and the World Bank. During the Green Revolution of the 1940s to 1970s, billions of dollars had been spent building large-scale irrigation systems. These contributed, along with new fertilizers, pesticides and high-yielding varieties of seeds, to helping many countries produce greater quantities of food crops. By the mid-1980s, however, these irrigation systems were no longer performing efficiently; IIMI's job was to find out why.
IIMI's researchers discovered that problems affecting irrigation were often more institutional than technical. It advocated ‘Participatory Irrigation Management’ (PIM) as the solution, an approach that sought to involve farmers in water management decisions. In 1992, the Rio de Janeiro Earth Summit gave credence to this approach by recommending that water management be decentralized, with farmers and other stakeholders playing a more important role in managing natural resources. Initially met with resistance, PIM went on to become the status quo for governments and major lending agencies. IIMI became a member of the CGIAR system in 1991.
Wider perspective
By the mid-1990s, competition for water resources was rising, thanks to a larger global population, expanding cities and increasing industrial applications. Viewing irrigation in isolation was no longer relevant to the global situation. A new approach was needed that would consider it within a river basin context, encompassing competing users and the environment. IIMI began developing new fields of research, on topics such as open and closed basins, water accounting, multiple-use systems, basin institutions, remote sensing analysis and environmental flows. In 1998, its name changed to the International Water Management Institute (IWMI), reflecting this new wider approach.
Although it was becoming evident that water could no longer be considered an "infinite resource", as had been the case in the 1950s when there were fewer people on the planet, no one knew just how scarce the resource was. This prompted IWMI to try to find out. Its research culminated in the publication of Water for food, Water for life: A comprehensive assessment of water management in agriculture. A map within the report showed that a third of the world's population already suffered from ‘water scarcity’. The report defined physical water scarcity, as being where there are insufficient water resources to meet the demands of the population, and economic water scarcity as where water requirements are not satisfied because of a lack of investment in water or human capacity.
Averting a global water crisis
IWMI's approach towards defining water scarcity provided a new context within which the scientific debate on water availability subsequently became centred. For example, the theme of the UN World Water Day in 2007 was Coping with Water Scarcity; The USA's Worldwatch Institute featured a chapter on water management in its assessment State of the World 2008; and reports published in 2009 by the World Economic Forum and UNESCO concluded that water scarcity is now a bigger threat than the global financial crisis. Dr. Rajendra K. Pachauri, Chair of the Intergovernmental Panel on Climate Change, also highlighted water scarcity at the 2009 Nobel Conference.
If current trends continue, global annual water usage is set to increase by more than two trillion cubic metres by 2030, rising to 6.9 trillion cubic metres. That equates to 40 per cent more than can be provided by available water supplies. At Stockholm World Water Week 2010, IWMI highlighted a six-point plan for averting a water crisis. According to the institute, the following actions are required: 1) gather high-quality data about water resources; 2) take better care of the environment; 3) reform how water resources are governed; 4) revitalize how water is used for farming; 5) better manage urban and municipal demands for water; and 6) involve marginalized people in water management.
In 2011, IWMI celebrated its 25th anniversary by commissioning a series of essays on agricultural and development.
Using water management to reduce poverty
IWM's work in Gujarat, India, exemplifies how improving water management can have an influence on peoples' livelihoods. The state faced the dual problem of bankrupt electricity utilities and depleted groundwater storage following the introduction of electricity subsidies to farmers from around 1970. The situation arose because the subsidies enabled farmers to easily pump groundwater from ever-increasing depths. The Asian Development Bank and World Bank both indicated that governments should cut the electricity subsidies and charge farmers based on metered consumption of power. However, when some state governments tried to do so, the farmers formed such powerful lobbies that several chief ministers lost their seats. A different solution was clearly required.
IWMI scientists who studied the problem suggested governments should introduce ‘intelligent rationing’ of farm power supply by separating the power cables carrying electricity to farmers from those supplying other rural users, such as domestic households and industries. They should then provide farmers with a high-quality power supply for a set number of hours each day at a price they could afford. Eventually Gujarat decided to include these recommendations in a larger programme to reform the electricity utility. A study conducted afterwards found its impacts to be much greater than anticipated. Prior to the change, tube-well owners had been holding rural communities to ransom by ‘stealing’ power for irrigation. After the cables were separated, rural households, schools and industries had a much higher-quality power supply, which in turn boosted individuals’ well-being.
See also
Environmental impact of irrigation
References
External links
International Water Management Institute
International Water Management Institute Publications
The World Bank's strategy, work and publications on water resources
International research institutes
Research institutes in Sri Lanka
Water and politics
Water and the environment
Water management
Water organizations
Water supply | International Water Management Institute | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 1,447 | [
"Hydrology",
"Water supply",
"Environmental engineering"
] |
2,263,276 | https://en.wikipedia.org/wiki/Phoenix%20Dwarf | The Phoenix Dwarf is a dwarf irregular galaxy discovered in 1976 by Hans-Emil Schuster and Richard Martin West and mistaken for a globular cluster. It is currently 1.44 Mly away from Earth. Its name comes from the fact that it is part of the Phoenix constellation.
Characteristics
The Phoenix Dwarf has an inner part of young stars which is stretched in an east-west direction and an outer part of mainly old stars that is stretched north-south. The central region's rate of star formation seems to have been relatively constant across time (Martínez-Delgado et al. 1999). In 1999, St-Germain et al. discovered a H I region of about 105 just to the west of Phoenix. Its radial velocity is −23 km/s and may be physically associated with Phoenix if it is found to have a similar radial velocity.
References
External links
Irregular galaxies
Dwarf irregular galaxies
Phoenix (constellation)
06830
? | Phoenix Dwarf | [
"Astronomy"
] | 187 | [
"Phoenix (constellation)",
"Constellations"
] |
2,263,499 | https://en.wikipedia.org/wiki/Digital%20clock | A digital clock displays the time digitally (i.e. in numerals or other symbols), as opposed to an analogue clock.
Digital clocks are often associated with electronic drives, but the "digital" description refers only to the display, not to the drive mechanism. (Both analogue and digital clocks can be driven either mechanically or electronically, but "clockwork" mechanisms with digital displays are rare.)
History
The first digital pocket watch was the invention of Austrian engineer Josef Pallweber who created his "jump-hour" mechanism in 1883. Instead of a conventional dial, the jump-hour featured two windows in an enamel dial, through which the hours and minutes are visible on rotating discs. The second hand remained conventional. By 1885, Pallweber mechanism was already on the market in pocket watches by Cortébert and IWC; arguably contributing to the subsequent rise and commercial success of IWC. The principles of Pallweber jump-hour movement had appeared in wristwatches by the 1920s (Cortébert) and are still used today (Chronoswiss Digiteur). While the original inventor did not have a watch brand at the time, his name has since been resurrected by a newly established watch manufacturer.
Plato clocks used a similar idea but a different layout. These spring-wound pieces consisted of a glass cylinder with a column inside, affixed to which were small digital cards with numbers printed on them, which flipped as time passed. The Plato clocks were introduced at the St. Louis World Fair in 1904, produced by Ansonia Clock Company. Eugene Fitch of New York patented the clock design in 1903.
Thirteen years earlier, Josef Pallweber had patented the same invention using digital cards (different from his 1885 patent using moving disks) in Germany (DRP No. 54093).
The German factory Aktiengesellschaft für Uhrenfabrikation Lenzkirch made such digital clocks in 1893 and 1894.
The earliest patent for a digital alarm clock was registered by D. E. Protzmann and others on October 23, 1956, in the United States. Protzmann and his associates also patented another digital clock in 1970, which was said to use a minimal amount of moving parts. Two side-plates held digital numerals between them, while an electric motor and cam gear outside controlled movement.
In 1970, the first digital wristwatch with an LED display was unveiled on The Tonight Show Starring Johnny Carson, although it was not released until 1972. Called the Pulsar, and produced by the Hamilton Watch Company, this watch was hinted at two years prior when the same company created a non-function digital watch prop (with a main analogue face but a secondary digital display) for Kubrick's 2001: A Space Odyssey.
Construction
Digital clocks typically use the 50 or 60 hertz oscillation of AC power or a 32,768 hertz crystal oscillator as in a quartz clock to keep time. Most digital clocks display the hour of the day in 24-hour format; in the United States and a few other countries, a commonly used hour sequence option is 12-hour format (with some indication of AM or PM). Some timepieces, such as many digital watches, can be switched between 12-hour and 24-hour modes. Emulations of analog-style faces often use an LCD screen, and these are also sometimes described as "digital".
Displays
To represent time, most digital clocks use a seven-segment LED, VFD, or LCD for each of the four digits. They generally also include other elements to indicate whether the time is AM or PM, whether or not an alarm is set, and so on. Older digital clocks used numbers painted on wheels, or a split-flap display. High-end digital clocks use dot matrix displays and use animations for digit changes.
Setting
If people find difficulty in setting the time in some designs of digital clocks in electronic devices where the clock is not a critical function, they may not be set at all, displaying the default after powered on, 00:00 or 12:00.
Because they run on electricity, digital clocks often need to be reset whenever the power is cut off, even for a very brief period of time. This is a particular problem with alarm clocks that have no "battery" backup, because a power outage during the night usually prevents the clock from triggering the alarm in the morning.
To reduce the problem, many devices designed to operate on household electricity incorporate a battery backup to maintain the time during power outages and during times of disconnection from the power supply. More recently, some devices incorporate a method for automatically setting the time, such as using a broadcast radio time signal from an atomic clock, getting the time from an existing satellite television or computer connection, or by being set at the factory and then maintaining the time from then on with a quartz movement powered by an internal rechargeable battery.
Commercial digital clocks are typically more reliable than consumer clocks. Multi-decade backup batteries can be used to maintain time during power loss.
Uses
Because digital clocks can be very small and inexpensive devices that enhance the popularity of product designs, they are often incorporated into all kinds of devices such as cars, radios, televisions, microwave ovens, standard ovens, computers and cell phones. Sometimes their usefulness is disputed: a common complaint is that when time has to be set to Daylight Saving Time, many household clocks have to be readjusted. The incorporation of automatic synchronization by a radio time signal is reducing this problem (see Radio clock). Smart digital clocks, in addition to displaying time, scroll additional information such as weather and notifications.
References
External links
History of the Digital Watch
Museum of Vintage Rare Digital LCD Wrist Watches
Austrian inventions
Clock designs
Clock | Digital clock | [
"Technology"
] | 1,183 | [
"Information and communications technology",
"Digital technology"
] |
2,263,904 | https://en.wikipedia.org/wiki/Carbon%20footprint | A carbon footprint (or greenhouse gas footprint) is a calculated value or index that makes it possible to compare the total amount of greenhouse gases that an activity, product, company or country adds to the atmosphere. Carbon footprints are usually reported in tonnes of emissions (CO2-equivalent) per unit of comparison. Such units can be for example tonnes CO2-eq per year, per kilogram of protein for consumption, per kilometer travelled, per piece of clothing and so forth. A product's carbon footprint includes the emissions for the entire life cycle. These run from the production along the supply chain to its final consumption and disposal.
Similarly, an organization's carbon footprint includes the direct as well as the indirect emissions that it causes. The Greenhouse Gas Protocol (for carbon accounting of organizations) calls these Scope 1, 2 and 3 emissions. There are several methodologies and online tools to calculate the carbon footprint. They depend on whether the focus is on a country, organization, product or individual person. For example, the carbon footprint of a product could help consumers decide which product to buy if they want to be climate aware. For climate change mitigation activities, the carbon footprint can help distinguish those economic activities with a high footprint from those with a low footprint. So the carbon footprint concept allows everyone to make comparisons between the climate impacts of individuals, products, companies and countries. It also helps people devise strategies and priorities for reducing the carbon footprint.
The carbon dioxide equivalent (CO2eq) emissions per unit of comparison is a suitable way to express a carbon footprint. This sums up all the greenhouse gas emissions. It includes all greenhouse gases, not just carbon dioxide. And it looks at emissions from economic activities, events, organizations and services. In some definitions, only the carbon dioxide emissions are taken into account. These do not include other greenhouse gases, such as methane and nitrous oxide.
Various methods to calculate the carbon footprint exist, and these may differ somewhat for different entities. For organizations it is common practice to use the Greenhouse Gas Protocol. It includes three carbon emission scopes. Scope 1 refers to direct carbon emissions. Scope 2 and 3 refer to indirect carbon emissions. Scope 3 emissions are those indirect emissions that result from the activities of an organization but come from sources which they do not own or control.
For countries it is common to use consumption-based emissions accounting to calculate their carbon footprint for a given year. Consumption-based accounting using input-output analysis backed by super-computing makes it possible to analyse global supply chains. Countries also prepare national GHG inventories for the UNFCCC. The GHG emissions listed in those national inventories are only from activities in the country itself. This approach is called territorial-based accounting or production-based accounting. It does not take into account production of goods and services imported on behalf of residents. Consumption-based accounting does reflect emissions from goods and services imported from other countries.
Consumption-based accounting is therefore more comprehensive. This comprehensive carbon footprint reporting including Scope 3 emissions deals with gaps in current systems. Countries' GHG inventories for the UNFCCC do not include international transport. Comprehensive carbon footprint reporting looks at the final demand for emissions, to where the consumption of the goods and services takes place.
Definition
A formal definition of carbon footprint is as follows: "A measure of the total amount of carbon dioxide (CO2) and methane (CH4) emissions of a defined population, system or activity, considering all relevant sources, sinks and storage within the spatial and temporal boundary of the population, system or activity of interest. Calculated as carbon dioxide equivalent using the relevant 100-year global warming potential (GWP100)."
Scientists report carbon footprints in terms of equivalents of tonnes of CO2 emissions (CO2-equivalent). They may report them per year, per person, per kilogram of protein, per kilometer travelled, and so on.
In the definition of carbon footprint, some scientists include only CO2. But more commonly they include several of the notable greenhouse gases. They can compare various greenhouse gases by using carbon dioxide equivalents over a relevant time scale, like 100 years. Some organizations use the term greenhouse gas footprint or climate footprint to emphasize that all greenhouse gases are included, not just carbon dioxide.
The Greenhouse Gas Protocol includes all of the most important greenhouse gases. "The standard covers the accounting and reporting of seven greenhouse gases covered by the Kyoto Protocol – carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PCFs), sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3)."
In comparison, the IPCC definition of carbon footprint in 2022 covers only carbon dioxide. It defines the carbon footprint as the "measure of the exclusive total amount of emissions of carbon dioxide (CO2) that is directly and indirectly caused by an activity or is accumulated over the lifecycle stages of a product." The IPCC report's authors adopted the same definition that had been proposed in 2007 in the UK. That publication included only carbon dioxide in the definition of carbon footprint. It justified this with the argument that other greenhouse gases were more difficult to quantify. This is because of their differing global warming potentials. They also stated that an inclusion of all greenhouse gases would make the carbon footprint indicator less practical. But there are disadvantages to this approach. One disadvantage of not including methane is that some products or sectors that have a high methane footprint such as livestock appear less harmful for the climate than they actually are.
Types of greenhouse gas emissions
The greenhouse gas protocol is a set of standards for tracking greenhouse gas emissions. The standards divide emissions into three scopes (Scope 1, 2 and 3) within the value chain. Greenhouse gas emissions caused directly by the organization such as by burning fossil fuels are referred to as Scope 1. Emissions caused indirectly by an organization, such as by purchasing secondary energy sources like electricity, heat, cooling or steam are called Scope 2. Lastly, indirect emissions associated with upstream or downstream processes are called Scope 3.
Direct carbon emissions (Scope 1)
Direct or Scope 1 carbon emissions come from sources on the site that is producing a product or delivering a service. An example for industry would be the emissions from burning a fuel on site. On the individual level, emissions from personal vehicles or gas-burning stoves are Scope 1.
Indirect carbon emissions (Scope 2)
Indirect carbon emissions are emissions from sources upstream or downstream from the process being studied. They are also known as Scope 2 or Scope 3 emissions.
Scope 2 emissions are the indirect emissions related to purchasing electricity, heat, or steam used on site. Examples of upstream carbon emissions include transportation of materials and fuels, any energy used outside of the production facility, and waste produced outside the production facility. Examples of downstream carbon emissions include any end-of-life process or treatments, product and waste transportation, and emissions associated with selling the product. The GHG Protocol says it is important to calculate upstream and downstream emissions. There could be some double counting. This is because upstream emissions of one person's consumption patterns could be someone else's downstream emissions
Other indirect carbon emissions (Scope 3)
Scope 3 emissions are all other indirect emissions derived from the activities of an organization. But they are from sources they do not own or control. The GHG Protocol's Corporate Value Chain (Scope 3) Accounting and Reporting Standard allows companies to assess their entire value chain emissions impact and identify where to focus reduction activities.
Scope 3 emission sources include emissions from suppliers and product users. These are also known as the value chain. Transportation of good, and other indirect emissions are also part of this scope. In 2022 about 30% of US companies reported Scope 3 emissions. The International Sustainability Standards Board is developing a recommendation to include Scope 3 emissions in all GHG reporting.
Purpose and strengths
The current rise in global average temperature is more rapid than previous changes. It is primarily caused by humans burning fossil fuels. The increase in greenhouse gases in the atmosphere is also due to deforestation and agricultural and industrial practices. These include cement production. The two most notable greenhouse gases are carbon dioxide and methane. Greenhouse gas emissions, and hence humanity's carbon footprint, have been increasing during the 21st century. The Paris Agreement aims to reduce greenhouse gas emissions enough to limit the rise in global temperature to no more than 1.5°C above pre-industrial levels.
The carbon footprint concept makes comparisons between the climate impacts of individuals, products, companies and countries. A carbon footprint label on products could enable consumers to choose products with a lower carbon footprint if they want to help limit climate change. For meat products, as an example, such a label could make it clear that beef has a higher carbon footprint than chicken.
Understanding the size of an organization's carbon footprint makes it possible to devise a strategy to reduce it. For most businesses the vast majority of emissions do not come from activities on site, known as Scope 1, or from energy supplied to the organization, known as Scope 2, but from Scope 3 emissions, the extended upstream and downstream supply chain. Therefore, ignoring Scope 3 emissions makes it impossible to detect all emissions of importance, which limits options for mitigation. Large companies in sectors such as clothing or automobiles would need to examine more than 100,000 supply chain pathways to fully report their carbon footprints.
The importance of displacement of carbon emissions has been known for some years. Scientists also call this carbon leakage. The idea of a carbon footprint addresses concerns of carbon leakage which the Paris Agreement does not cover. Carbon leakage occurs when importing countries outsource production to exporting countries. The outsourcing countries are often rich countries while the exporters are often low-income countries. Countries can make it appear that their GHG emissions are falling by moving "dirty" industries abroad, even if their emissions could be increasing when looked at from a consumption perspective.
Carbon leakage and related international trade have a range of environmental impacts. These include increased air pollution, water scarcity, biodiversity loss, raw material usage, and energy depletion.
Scholars have argued in favour of using both consumption-based and production-based accounting. This helps establish shared producer and consumer responsibility. Currently countries report on their annual GHG inventory to the UNFCCC based on their territorial emissions. This is known as the territorial-based or production-based approach. Including consumption-based calculations in the UNFCCC reporting requirements would help close loopholes by addressing the challenge of carbon leakage.
The Paris Agreement currently does not require countries to include in their national totals GHG emissions associated with international transport. These emissions are reported separately. They are not subject to the limitation and reduction commitments of Annex 1 Parties under the Climate Convention and Kyoto Protocol. The carbon footprint methodology includes GHG emissions associated with international transport, thereby assigning emissions caused by international trade to the importing country.
Underlying concepts for calculations
The calculation of the carbon footprint of a product, service or sector requires expert knowledge and careful examination of what is to be included. Carbon footprints can be calculated at different scales. They can apply to whole countries, cities, neighborhoods and also sectors, companies and products. Several free online carbon footprint calculators exist to calculate personal carbon footprints.
Software such as the "Scope 3 Evaluator" can help companies report emissions throughout their value chain. The software tools can help consultants and researchers to model global sustainability footprints. In each situation there are a number of questions that need to be answered. These include which activities are linked to which emissions, and which proportion should be attributed to which company. Software is essential for company management. But there is a need for new ways of enterprise resource planning to improve corporate sustainability performance.
To achieve 95% carbon footprint coverage, it would be necessary to assess 12 million individual supply-chain contributions. This is based on analyzing 12 sectoral case studies. The Scope 3 calculations can be made easier using input-output analysis. This is a technique originally developed by Nobel Prize-winning economist Wassily Leontief.
Consumption-based emission accounting based on input-output analysis
Consumption-based emission accounting traces the impacts of demand for goods and services along the global supply chain to the end-consumer. It is also called consumption-based carbon accounting. In contrast, a production-based approach to calculating GHG emissions is not a carbon footprint analysis. This approach is also called a territorial-based approach. The production-based approach includes only impacts physically produced in the country in question. Consumption-based accounting redistributes the emissions from production-based accounting. It considers that emissions in another country are necessary for the home country's consumption bundle.
Consumer-based accounting is based on input-output analysis. It is used at the highest levels for any economic research question related to environmental or social impacts. Analysis of global supply chains is possible using consumption-based accounting with input-output analysis assisted by super-computing capacity.
Leontief created Input-output analysis (IO) to demonstrate the relationship between consumption and production in an economy. It incorporates the entire supply chain. It uses input-output tables from countries' national accounts. It also uses international data such as UN Comtrade and Eurostat. Input-output analysis has been extended globally to multi-regional input-output analysis (MRIO). Innovations and technology enabling the analysis of billions of supply chains made this possible. Standards set by the United Nations underpin this analysis. The analysis enables a Structural Path Analysis. This scans and ranks the top supply chain nodes and paths. It conveniently lists hotspots for urgent action. Input-output analysis has increased in popularity because of its ability to examine global value chains.
Combination with life cycle analysis (LCA)
Life cycle assessment (LCA) is a methodology for assessing all environmental impacts associated with the life cycle of a commercial product, process, or service. It is not limited to the greenhouse gas emissions. It is also called life cycle analysis. It includes water pollution, air pollution, ecotoxicity and similar types of pollution. Some widely recognized procedures for LCA are included in the ISO 14000 series of environmental management standards. A standard called ISO 14040:2006 provides the framework for conducting an LCA study. ISO 14060 family of standards provides further sophisticated tools. These are used to quantify, monitor, report and validate or verify GHG emissions and removals.
Greenhouse gas product life cycle assessments can also comply with specifications such as Publicly Available Specification (PAS) 2050 and the GHG Protocol Life Cycle Accounting and Reporting Standard.
An advantage of LCA is the high level of detail that can be obtained on-site or by liaising with suppliers. However, LCA has been hampered by the artificial construction of a boundary after which no further impacts of upstream suppliers are considered. This can introduce significant truncation errors. LCA has been combined with input-output analysis. This enables on-site detailed knowledge to be incorporated. IO connects to global economic databases to incorporate the entire supply chain.
Problems
Shifting responsibility from corporations to individuals
Critics argue that the original aim of promoting the personal carbon footprint concept was to shift responsibility away from corporations and institutions and on to personal lifestyle choices. The fossil fuel company BP ran a large advertising campaign for the personal carbon footprint in 2005 which helped popularize this concept. This strategy, employed by many major fossil fuel companies, has been criticized for trying to shift the blame for negative consequences of those industries on to individual choices.
Geoffrey Supran and Naomi Oreskes of Harvard University argue that concepts such as carbon footprints "hamstring us, and they put blinders on us, to the systemic nature of the climate crisis and the importance of taking collective action to address the problem".
Relationship with other environmental impacts
A focus on carbon footprints can lead people to ignore or even exacerbate other related environmental issues of concern. These include biodiversity loss, ecotoxicity, and habitat destruction. It may not be easy to measure these other human impacts on the environment with a single indicator like the carbon footprint. Consumers may think that the carbon footprint is a proxy for environmental impact. In many cases this is not correct. There can be trade-offs between reducing carbon footprint and environmental protection goals. One example is the use of biofuel, a renewable energy source and can reduce the carbon footprint of energy supply but can also pose ecological challenges during its production. This is because it is often produced in monocultures with ample use of fertilizers and pesticides. Another example is offshore wind parks, which could have unintended impacts on marine ecosystems.
The carbon footprint analysis solely focuses on greenhouse gas emissions, unlike a life-cycle assessment which is much broader and looks at all environmental impacts. Therefore, it is useful to stress in communication activities that the carbon footprint is just one in a family of indicators (e.g. ecological footprint, water footprint, land footprint, and material footprint), and should not be looked at in isolation. In fact, carbon footprint can be treated as one component of ecological footprint.
The "Sustainable Consumption and Production Hotspot Analysis Tool" (SCP-HAT) is a tool to place carbon footprint analysis into a wider perspective. It includes a number of socio-economic and environmental indicators. It offers calculations that are either consumption-based, following the carbon footprint approach, or production-based. The database of the SCP-HAT tool is underpinned by input–output analysis. This means it includes Scope 3 emissions. The IO methodology is also governed by UN standards. It is based on input-output tables of countries' national accounts and international trade data such as UN Comtrade, and therefore it is comparable worldwide.
Differing boundaries for calculations
The term carbon footprint has been applied to limited calculations that do not include Scope 3 emissions or the entire supply chain. This can lead to claims of misleading customers with regards to the real carbon footprints of companies or products.
Reported values
Greenhouse gas emissions overview
By products
The Carbon Trust has worked with UK manufacturers to produce "thousands of carbon footprint assessments". As of 2014 the Carbon Trust state they have measured 28,000 certifiable product carbon footprints.
Food
Plant-based foods tend to have a lower carbon footprint than meat and dairy. In many cases a much smaller footprint. This holds true when comparing the footprint of foods in terms of their weight, protein content or calories. The protein output of peas and beef provides an example. Producing 100 grams of protein from peas emits just 0.4 kilograms of carbon dioxide equivalents (CO2eq). To get the same amount of protein from beef, emissions would be nearly 90 times higher, at 35 kgCO2eq. Only a small fraction of the carbon footprint of food comes from transport and packaging. Most of it comes from processes on the farm, or from land use change. This means the choice of what to eat has a larger potential to reduce carbon footprint than how far the food has traveled, or how much packaging it is wrapped in.
By sector
The IPCC Sixth Assessment Report found that global GHG emissions have continued to rise across all sectors. Global consumption was the main cause. The most rapid growth was in transport and industry. A key driver of global carbon emissions is affluence. The IPCC noted that the wealthiest 10% in the world contribute between about one third to one half (36%–45%) of global GHG emissions. Researcheres have previously found that affluence is the key driver of carbon emissions. It has a bigger impact than population growth. And it counters the effects of technological developments. Continued economic growth mirrors the increasing trend in material extraction and GHG emissions. “Industrial emissions have been growing faster since 2000 than emissions in any other sector, driven by increased basic materials extraction and production,” the IPCC said.
Transport
There can be wide variations in emissions for transport of people. This is due to various factors. They include the length of the trip, the source of electricity in the local grid and the occupancy of public transport. In the case of driving the type of vehicle and number of passengers are factors. Over short to medium distances, walking or cycling are nearly always the lowest carbon way to travel. The carbon footprint of cycling one kilometer is usually in the range of 16 to 50 grams CO2eq per km. For moderate or long distances, trains nearly always have a lower carbon footprint than other options.
By organization
Carbon accounting
By country
CO2 emissions of countries are typically measured on the basis of production. This accounting method is sometimes referred to as territorial emissions. Countries use it when they report their emissions, and set domestic and international targets such as Nationally Determined Contributions. Consumption-based emissions on the other hand are adjusted for trade. To calculate consumption-based emissions analysts have to track which goods are traded across the world. Whenever a product is imported, all CO2 emissions that were emitted in the production of that product are included. Consumption-based emissions reflect the lifestyle choices of a country's citizens.
According to the World Bank, the global average carbon footprint in 2014 was about 5 tonnes of CO2 per person, measured on a production basis. The EU average for 2007 was about 13.8 tonnes CO2e per person. For the USA, Luxembourg and Australia it was over 25 tonnes CO2e per person. In 2017, the average for the USA was about 20 metric tonnes CO2e per person. This is one of the highest per capita figures in the world.
The footprints per capita of countries in Africa and India were well below average. Per capita emissions in India are low for its huge population. But overall the country is the third largest emitter of CO2 and fifth largest economy by nominal GDP in the world. Assuming a global population of around 9–10 billion by 2050, a carbon footprint of about 2–2.5 tonnes CO2e per capita is needed to stay within a 2 °C target. These carbon footprint calculations are based on a consumption-based approach using a Multi-Regional Input-Output (MRIO) database. This database accounts for all greenhouse gas (GHG) emissions in the global supply chain and allocates them to the final consumer of the purchased commodities.
Reducing the carbon footprint
Climate change mitigation
Efforts to reduce the carbon footprint of products, services and organizations help limit climate change. Such activities are called climate change mitigation.
Reducing industry's carbon footprint
Carbon offsetting can reduce a company's overall carbon footprint by providing it with a carbon credit. This compensates the company for carbon dioxide emissions by recognizing an equivalent reduction of carbon dioxide in the atmosphere. Reforestation, or restocking existing forests that have previously been depleted, is an example of carbon offsetting.
A carbon footprint study can identify specific and critical areas for improvement. It uses input-output analysis and scrutinizes the entire supply chain. Such an analysis could be used to eliminate the supply chains with the highest greenhouse gas emissions.
History
The term carbon footprint was first used in a BBC vegetarian food magazine in 1999, though the broader concept of ecological footprint, which encompasses the carbon footprint, had been used since at least 1992, as also chronicled by William Safire in the New York Times.
In 2005, fossil fuel company BP hired the large advertising campaign Ogilvy to popularize the idea of a carbon footprint for individuals. The campaign instructed people to calculate their personal footprints and provided ways for people to "go on a low-carbon diet".
The carbon footprint is derived from the ecological footprint, which encompasses carbon emissions. The carbon footprint follows the logic of ecological footprint accounting, which tracks the resource use embodied in consumption, whether it is a product, an individual, a city, or a country. While in the ecological footprint, carbon emissions are translated into areas needed to absorb the carbon emissions, the carbon footprint on its own is expressed in the weight of carbon emissions per time unit. William Rees wrote the first academic publication about ecological footprints in 1992. Other related concepts from the 1990s are the "ecological backpack" and material input per unit of service (MIPS).
Trends and similar concepts
The International Sustainability Standards Board (ISSB) aims to bring global, rigorous oversight to carbon footprint reporting. It was formed out of the International Financial Reporting Standards. It will require companies to report on their Scope 3 emissions. The ISSB has taken on board criticisms of other initiatives in its aims for universality. It consolidates the Carbon Disclosure Standards Board, the Sustainability Accounting Standards Board and the Value Reporting Foundation. It complements the Global Reporting Initiative. It is influenced by the Task Force on Climate-Related Financial Disclosures. As of early 2023, Great Britain and Nigeria were preparing to adopt these standards.
The concept of total equivalent warming impact (TEWI) is the most used index for carbon dioxide equivalent (CO2) emissions calculation in air conditioning and refrigeration sectors by including both the direct and indirect contributions since it evaluates the emissions caused by the operating lifetime of systems. The Expanded Total Equivalent Warming Impact method has been used for an accurate evaluation of refrigerators emissions.
See also
Carbon emission
Carbon intensity
Carbon neutrality
Ecological footprint
Embedded emissions
Food miles
Greenhouse gas inventory
Individual action on climate change
Life-cycle greenhouse gas emissions of energy sources
Zero-carbon city
References
External links
The GHG Protocol
Environmental impact of the energy industry
Greenhouse gas emissions
Environmental indices
Environmental terminology
Articles containing video clips | Carbon footprint | [
"Chemistry"
] | 5,190 | [
"Greenhouse gases",
"Greenhouse gas emissions"
] |
2,263,974 | https://en.wikipedia.org/wiki/Bouveault%E2%80%93Blanc%20reduction | The Bouveault–Blanc reduction is a chemical reaction in which an ester is reduced to primary alcohols using absolute ethanol and sodium metal. It was first reported by Louis Bouveault and Gustave Louis Blanc in 1903. Bouveault and Blanc demonstrated the reduction of ethyl oleate and n-butyl oleate to oleyl alcohol. Modified versions of which were subsequently refined and published in Organic Syntheses.
This reaction is used commercially although for laboratory scale reactions it was made obsolete by the introduction of lithium aluminium hydride.
Reaction mechanism
Sodium metal is a one-electron reducing agent. Four equivalents of sodium are required to fully reduce each ester, although two more equivalents are typically consumed in deprotonating the product alcohols to alkoxides. Ethanol serves as a proton source. The reaction produces sodium alkoxides, according to the following stoichiometry:
+ 6 Na + 4 → + + 4
In practice, considerable sodium is consumed by the formation of hydrogen. For this reason, an excess of sodium is often required. Because the hydrolysis of sodium is rapid, not to mention dangerous, the Bouveault-Blanc reaction requires anhydrous ethanol and can give low yields with insufficiently dry ethanol. The mechanism of the reaction follows:
Consistent with this mechanism, sodium-ethanol mixtures will also reduce ketones to alcohols.
This approach to reducing esters was widely used prior to the availability of hydride reducing agents such as lithium aluminium hydride and related reagents. It requires vigorous reaction conditions and has a significant risk of fires, explaining its relative unpopularity. One modification involves encapsulating the alkali metal into a silica gel, which has a safety and yield profile similar to that of hydride reagents. Another modification uses a sodium dispersion.
See also
Acyloin condensation – The reductive coupling of esters, using sodium, to yield an α-hydroxyketone
Akabori amino-acid reaction – The reduction of amino acid esters, by sodium, to yield aldehydes
Birch reduction – For the reduction of alkenes using sodium
Bouveault aldehyde synthesis – Another organometallic reaction by Bouveault where a Grignard reagent is converted to an aldehyde
References
External links
Animation of the Bouveault–Blanc reduction
Free radical reactions
Organic redox reactions
Name reactions | Bouveault–Blanc reduction | [
"Chemistry"
] | 499 | [
"Name reactions",
"Free radical reactions",
"Organic redox reactions",
"Organic reactions"
] |
2,264,346 | https://en.wikipedia.org/wiki/Electron%20configurations%20of%20the%20elements%20%28data%20page%29 | This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. For phosphorus (element 15) as an example, the concise form is [Ne] 3s2 3p3. Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s2 3p3) are written explicitly for all atoms.
Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.
As an approximate rule, electron configurations are given by the Aufbau principle and the Madelung rule. However there are numerous exceptions; for example the lightest exception is chromium, which would be predicted to have the configuration , written as , but whose actual configuration given in the table below is .
Note that these electron configurations are given for neutral atoms in the gas phase, which are not the same as the electron configurations for the same atoms in chemical environments. In many cases, multiple configurations are within a small range of energies and the irregularities shown below do not necessarily have a clear relation to chemical behaviour. For the undiscovered eighth-row elements, mixing of configurations is expected to be very important, and sometimes the result can no longer be well-described by a single configuration.
See also
Extended periodic table#Electron configurations – Predictions for undiscovered elements 119–173 and 184
References
All sources concur with the data above except in the instances listed separately:
NIST
http://physics.nist.gov/PhysRefData/IonEnergy/ionEnergy.html ; retrieved July 2005, (elements 1–104) based on:
Atomic Spectroscopy, by W.C. Martin and W.L. Wiese in Atomic, Molecular, & Optical Physics Handbook, ed. by G.W.F. Drake (AIP, Woodbury, NY, 1996) Chapter 10, pp. 135–153.
This website is also cited in the CRC Handbook as source of Section 1, subsection Electron Configuration of Neutral Atoms in the Ground State.
91 Pa : [Rn] 5f2(3H4) 6d 7s2
92 U : [Rn] 5f3(4Io9/2) 6d 7s2
93 Np : [Rn] 5f4(5I4) 6d 7s2
103 Lr : [Rn] 5f14 7s2 7p1 question-marked
104 Rf : [Rn] 5f14 6d2 7s2 question-marked
CRC
David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition, online version. CRC Press. Boca Raton, Florida, 2003; Section 1, Basic Constants, Units, and Conversion Factors; Electron Configuration of Neutral Atoms in the Ground State. (elements 1–104)
Also subsection Periodic Table of the Elements, (elements 1–103) based on:
G. J. Leigh, Editor, Nomenclature of Inorganic Chemistry, Blackwell Scientific Publications, Oxford, 1990.
Chemical and Engineering News, 63(5), 27, 1985.
Atomic Weights of the Elements, 1999, Pure Appl. Chem., 73, 667, 2001.
WebElements
http://www.webelements.com/ ; retrieved July 2005, electron configurations based on:
Atomic, Molecular, & Optical Physics Handbook, Ed. Gordon W. F. Drake, American Institute of Physics, Woodbury, New York, 1996.
J.E. Huheey, E.A. Keiter, and R.L. Keiter in Inorganic Chemistry : Principles of Structure and Reactivity, 4th edition, Harper Collins, New York, 1993.
R.L. DeKock and H.B. Gray in Chemical Structure and bonding, Benjamin/Cummings, Menlo Park, California, 1980.
A.M. James and M.P. Lord in Macmillan's Chemical and Physical Data, Macmillan, London, UK, 1992.
103 Lr : [Rn].5f14.7s2.7p1 tentative ; 2.8.18.32.32.9.2 [inconsistent]
104 Rf : [Rn].5f14.6d2.7s2 tentative
105 Db : [Rn].5f14.6d3.7s2 (a guess based upon that of tantalum) ; 2.8.18.32.32.11.2
106 Sg : [Rn].5f14.6d4.7s2 (a guess based upon that of tungsten) ; 2.8.18.32.32.12.2
107 Bh : [Rn].5f14.6d5.7s2 (a guess based upon that of rhenium) ; 2.8.18.32.32.13.2
108 Hs : [Rn].5f14.6d6.7s2 (a guess based upon that of osmium) ; 2.8.18.32.32.14.2
109 Mt : [Rn].5f14.6d7.7s2 (a guess based upon that of iridium) ; 2.8.18.32.32.15.2
110 Ds : [Rn].5f14.6d9.7s1 (a guess based upon that of platinum) ; 2.8.18.32.32.17.1
111 Rg : [Rn].5f14.6d10.7s1 (a guess based upon that of gold) ; 2.8.18.32.32.18.1
112 Cn : [Rn].5f14.6d10.7s2 (a guess based upon that of mercury) ; 2.8.18.32.32.18.2
113 Nh : [Rn].5f14.6d10.7s2.7p1 (a guess based upon that of thallium) ; 2.8.18.32.32.18.3
114 Fl : [Rn].5f14.6d10.7s2.7p2 (a guess based upon that of lead) ; 2.8.18.32.32.18.4
115 Mc : [Rn].5f14.6d10.7s2.7p3 (a guess based upon that of bismuth) ; 2.8.18.32.32.18.5
116 Lv : [Rn].5f14.6d10.7s2.7p4 (a guess based upon that of polonium) ; 2.8.18.32.32.18.6
117 Ts : [Rn].5f14.6d10.7s2.7p5 (a guess based upon that of astatine) ; 2.8.18.32.32.18.7
118 Og : [Rn].5f14.6d10.7s2.7p6 (a guess based upon that of radon) ; 2.8.18.32.32.18.8
Lange
J.A. Dean (ed), Lange's Handbook of Chemistry (15th Edition), online version, McGraw-Hill, 1999; Section 4, Table 4.1 Electronic Configuration and Properties of the Elements. (Elements 1–103)
97 Bk : [Rn] 5f8 6d 7s2
103 Lr : [Rn] 4f14 [sic] 6d 7s2
Hill and Petrucci
Hill and Petrucci, General Chemistry: An Integrated Approach (3rd edition), Prentice Hall. (Elements 1–106)
58 Ce : [Xe] 4f2 6s2
103 Lr : [Rn] 5f14 6d1 7s2
104 Rf : [Rn] 5f14 6d2 7s2 (agrees with guess above)
105 Db : [Rn] 5f14 6d3 7s2
106 Sg : [Rn] 5f14 6d4 7s2
Hoffman, Lee, and Pershina
This book contains predicted electron configurations for the elements up to 172, as well as 184, based on relativistic Dirac–Fock calculations by B. Fricke in
Chemical element data pages | Electron configurations of the elements (data page) | [
"Physics",
"Chemistry"
] | 1,791 | [
"Chemical element data pages",
"Atoms",
"Matter",
"Chemical data pages"
] |
2,264,916 | https://en.wikipedia.org/wiki/Hook%20effect | The hook effect refers to the prozone phenomenon, also known as antibody excess, or the postzone phenomenon, also known as antigen excess. It is an immunologic phenomenon whereby the effectiveness of antibodies to form immune complexes can be impaired when concentrations of an antibody or an antigen are very high. The formation of immune complexes stops increasing with greater concentrations and then decreases at extremely high concentrations, producing a hook shape on a graph of measurements. An important practical relevance of the phenomenon is as a type of interference that plagues certain immunoassays and nephelometric assays, resulting in false negatives or inaccurately low results. Other common forms of interference include antibody interference, cross-reactivity and signal interference. The phenomenon is caused by very high concentrations of a particular analyte or antibody and is most prevalent in one-step (sandwich) immunoassays.
Mechanism and in vitro importance
Prozone – excess antibodies
In an agglutination test, a person's serum (which contains antibodies) is added to a test tube, which contains a particular antigen. If the antibodies interact with the antigen to form immune complexes, called agglutination, then the test is interpreted as positive. However, if too many antibodies that can bind to the antigen are present, then the antigenic sites are coated by antibodies, and few or no antibodies directed toward the pathogen are able to bind more than one antigenic particle. Since the antibodies do not bridge between antigens, no agglutination occurs. Because no agglutination occurs, the test is interpreted as negative. In this case, the result is a false negative. The range of relatively high antibody concentrations within which no reaction occurs is called the prozone.
Postzone – excess antigens
The effect can also occur because of antigen excess, when both the capture and detection antibodies become saturated by the high analyte concentration. In this case, no sandwich can be formed by the capturing antibody, the antigen and the detection antibody. In this case, free antigen is in competition with captured antigen for detection antibody binding. Sequential addition of antigen and antibody, paired with stringent washing, can prevent the effect, as can increasing the relative concentration of antibody to antigen, thereby mediating the effect.
Examples include high levels of syphilis antibodies in HIV patients or high levels of cryptococcal antigen leading to false negative tests in undiluted samples. This phenomenon is also seen in serological tests for Brucellosis. It may be seen in precipitation reactions. The antibody that fails to react is known as the blocking antibody and prevents the precipitating antibody from binding to the antigens. Thus the proper precipitation reaction does not take place. However, when the serum is diluted, the blocking antibody is as well and its concentration decreases enough for the proper precipitation reaction to occur.
In vivo observations
Lewis Thomas described in his memoir a physiologic experiment of 1941 in which he observed the prozone effect in vivo: immunity in rabbits to meningococcus, which was robust, unexpectedly decreased when immunization was used to induce a heightened antibody response. In other words, getting the rabbits' bodies to produce more antibodies against this bacterium had the counterproductive effect of decreasing their immunity to it. From the viewpoint of an overly simplistic notion of the antibody/antigen relationship, this seems paradoxical, although it is clearly logical from a viewpoint duly informed by present-day molecular biology. Thomas was interested in pursuing this physiologic research further, and remained so for decades afterward, but his career took him in other directions and he was not aware of anyone having pursued it by the time of his memoir. One kind of relevance that he hypothesized for this in vivo blocking antibody concept was as a driver of human susceptibility to certain infectious diseases. In the decades since, the concept has also been found to have clinical relevance in allergen immunotherapy, where blocking antibodies can interfere with other antibodies involved in hypersensitivity and thus improve allergy treatment.
See also
Blocking antibody
References
Immunologic tests
Hematology | Hook effect | [
"Biology"
] | 840 | [
"Immunologic tests"
] |
2,265,023 | https://en.wikipedia.org/wiki/Field%20emission%20gun | A field emission gun (FEG) is a type of electron gun in which a sharply pointed Müller-type emitter is held at several kilovolts negative potential relative to a nearby electrode, so that there is sufficient potential gradient at the emitter surface to cause field electron emission. Emitters are either of cold-cathode type, usually made of single crystal tungsten sharpened to a tip radius of about 100 nm, or of the Schottky type, in which thermionic emission is enhanced by barrier lowering in the presence of a high electric field. Schottky emitters are made by coating a tungsten tip with a layer of zirconium oxide (ZrO2) decreasing the work function of the tip by approximately 2.7 eV.
In electron microscopes, a field emission gun is used to produce an electron beam that is smaller in diameter, more coherent and with up to three orders of magnitude greater current density or brightness than can be achieved with conventional thermionic emitters such as tungsten or lanthanum hexaboride ()-tipped filaments. The result in both scanning and transmission electron microscopy is significantly improved signal-to-noise ratio and spatial resolution, and greatly increased emitter life and reliability compared with thermionic devices.
References
Vacuum tubes
Tungsten | Field emission gun | [
"Physics"
] | 270 | [
"Vacuum tubes",
"Vacuum",
"Matter"
] |
2,265,029 | https://en.wikipedia.org/wiki/Ion%20wind | Ion wind, ionic wind, corona wind or electric wind is the airflow of charged particles induced by electrostatic forces linked to corona discharge arising at the tips of some sharp conductors (such as points or blades) subjected to high voltage relative to ground. Ion wind is an electrohydrodynamic phenomenon. Ion wind generators can also be considered electrohydrodynamic thrusters.
The term "ionic wind" is considered a misnomer due to misconceptions that only positive and negative ions were primarily involved in the phenomenon. A 2018 study found that electrons play a larger role than negative ions during the negative voltage period. As a result, the term "electric wind" has been suggested as a more accurate terminology.
This phenomenon is now used in an MIT ionic wind plane, the first solid-state plane, developed in 2018.
History
B. Wilson in 1750 demonstrated the recoil force associated to the same corona discharge and precursor to the ion thruster was the corona discharge pinwheel. The corona discharge from the freely rotating pinwheel arm with ends bent to sharp points gives the air a space charge, which repels the point because the polarity is the same for the point and the air.
Francis Hauksbee, curator of instruments for the Royal Society of London, made the earliest report of electric wind in 1709. Myron Robinson completed an extensive bibliography and literature review during the 1950s resurgence of interest in the phenomena.
In 2018, researchers from South Korea and Slovenia used Schlieren photography to experimentally determine that electrons and ions play an important role in generating ionic wind. The study was the first to provide direct evidence that the electrohydrodynamic force responsible for the ionic wind is caused by a charged particle drag that occurs as the electrons and ions push the neutral particles away.
In 2018, a team of MIT researchers built and successfully flew the first-ever prototype plane propelled by ionic wind, MIT EAD Airframe Version 2.
Mechanism
Net electric charges on conductors, including local charge distributions associated with dipoles, reside entirely on their external surface (see Faraday cage) and tend to concentrate more around sharp points and edges than on flat surfaces. This means that the electric field generated by charges on a sharp conductive point is much stronger than the field generated by the same charge residing on a large, smooth, spherical conductive shell. When this electric field strength exceeds what is known as the corona discharge inception voltage (CIV) gradient, it ionizes the air about the tip, and a small faint purple jet of plasma can be seen in the dark on the conductive tip. Ionization of the nearby air molecule results in the n generation of ionized air molecules having the same polarity as that of the charged tip. Subsequently, the tip repels the like-charged ion cloud, which immediately expands due to the repulsion between the ions themselves. This repulsion of ions creates an electric "wind" that emanates from the tip, usually accompanied by a hissing noise due to the change in air pressure at the tip. An opposite force acts on the tip that may recoil if not tight to the ground.
A vaneless ion wind generator performs the inverse function, using ambient wind to move ions, which are collected, yielding electrical energy.
See also
Air ioniser
Ion thruster
Ionocraft
Plasma actuator
Hall-effect thruster
Magnetohydrodynamic drive
Magnetoplasmadynamic thruster
Pulsed inductive thruster
Field-emission electric propulsion
Spacecraft propulsion
References
External links
The Man Who Mastered Gravity (Townsend Brown Biography) by Paul Schatzkin; 2023 Incorrigible Arts,
Plasma propulsion in space
Plasma phenomena
Spacecraft propulsion
Electrostatics | Ion wind | [
"Physics"
] | 749 | [
"Plasma phenomena",
"Physical phenomena",
"Plasma physics"
] |
13,605,305 | https://en.wikipedia.org/wiki/Androdioecy | Androdioecy is a reproductive system characterized by the coexistence of males and hermaphrodites. Androdioecy is rare in comparison with the other major reproductive systems: dioecy, gynodioecy and hermaphroditism. In animals, androdioecy has been considered a stepping stone in the transition from dioecy to hermaphroditism, and vice versa.
Androdioecy, trioecy and gynodioecy are sometimes referred to as a mixed mating systems. Androdioecy is a dimorphic sexual system in plants comparable with gynodioecy and dioecy.
Evolution of androdioecy
The fitness requirements for androdioecy to arise and sustain itself are theoretically so improbable that it was long considered that such systems do not exist. Particularly, males and hermaphrodites have to have the same fitness, in other words produce the same number of offspring, in order to be maintained. However, males only have offspring by fertilizing eggs or ovules of hermaphrodites, while hermaphrodites have offspring both through fertilizing eggs or ovules of other hermaphrodites and their own ovules. This means that all else being equal, males have to fertilize twice as many eggs or ovules as hermaphrodites to make up for the lack of female reproduction.
Androdioecy can evolve either from hermaphroditic ancestors through the invasion of males or from dioecious ancestors through the invasion of hermaphrodites. The ancestral state is important because conditions under which androdioecy can evolve differ significantly.
Androdioecy with dioecious ancestry
In roundworms, clam shrimp, tadpole shrimp and cancrid shrimps, androdioecy has evolved from dioecy. In these systems, hermaphrodites can only fertilize their own eggs (self-fertilize) and do not mate with other hermaphrodites. Males are the only means of outcrossing. Hermaphrodites may be beneficial in colonizing new habitats, because a single hermaphrodite can generate many other individuals.
In the well-studied roundworm Caenorhabditis elegans, males are very rare and only occur in populations that are in bad condition or stressed. In Caenorhabditis elegans androdioecy is thought to have evolved from dioecy, through a trioecous intermediate.
Androdioecy with hermaphroditic ancestry
In barnacles, androdioecy evolved from hermaphroditism. Many plants self-fertilize, and males may be sustained in a population when inbreeding depression is severe because males guarantee outcrossing.
Types of androdioecy
The most common form of androdioecy in animals involves hermaphrodites that can reproduce by autogamy or allogamy through ovum with males. However, this type does not involve outcrossing with sperm. This type of androdioecy generally occurs in predominantly gonochoric taxonomy groups.
One type of androdioecy contains outcrossing hermaphrodites which is present in some angiosperms.
Another type of androdioecy has males and simultaneous hermaphrodites in a population due to developmental or conditional sex allocation. Like in some fish species small individuals are hermaphrodites and under circumstances of high density, large individuals become male.
Androdioecious species
Despite their unlikely evolution, 115 androdioecious animal and about 50 androdioecious plant species are known. These species include
Anthozoa (Corals)
Goniastra australensis
Stylophora pistillata
Nematoda (Roundworms)
Rhabditidae (Order Rhabditida)
Caenorhabditis briggsae
Caenorhabditis elegans
Caenorhabditis sp. 11
Oscheius myriophila
Oscheius dolchura
Oscheius tipulae
Oscheius guentheri
Rhabditis rainai
Rhabditis sp. (AF5)
Rhabdias nigrovenosum
Rhabdias rubrovenosa
Rhabdias ranae
Entomelas entomelas
Diplogastridae (Order Rhabditida)
Allodiplogaster sudhausi
Diplogasteroides magnus
Levipalatum texanum
Pristionchus boliviae
Pristionchus fissidentatus
Pristionchus maupasi
Pristionchus mayeri
Pristionchus pacificus
Pristionchus triformis
Sudhausia aristotokia
Sudhausia crassa
Steinernematidae (Order Rhabditida)
Steinernema hermaphroditum
Allanotnematidae (Order Rhabditida)
Allantonema mirabile
Bradynema rigidum
Dorylaimida
Dorylaimus liratus
Nemertea (Ribbon worms)
Prostoma eilhardi
Arthropoda
Clam shrimp
Eulimnadia texana
Eulimnadia africana
Eulimnadia agassizii
Eulimnadia antlei
Eulimnadia braueriana
Eulimnadia brasiliensis
Eulimnadia colombiensis
Eulimnadia cylondrova
Eulimnadia dahli
Eulimnadia diversa
Eulimnadia feriensis
Eulimnadia follisimilis
Eulimnadia thompsoni
Eulimnadia sp. A
Eulimnadia sp. B
Eulimnadia sp. C
Tadpole shrimp
Triops cancriformis
Triops newberryi
Triops longicaudatus
Barnacles
Paralepas klepalae
Paralepas xenophorae
Koleolepas avis
Koleolepas tinkeri
Ibla quadrivalvis
Ibla cumingii
Ibla idiotica
Ibla segmentata
Calantica studeri
Calantica siemensi
Calantica spinosa
Calantica villosa
Arcoscalpellum sp.
Euscalpellum squamuliferum
Scalpellum peronii
Scalpellum scalpellum
Scalpellum vulgare
Scillaelepas arnaudi
Scillaelepas bocquetae
Scillaelepas calyculacilla
Scillaelepas falcate
Scillaelepas fosteri
Smilium hastatum
Smilium peronii
Chelonibia patula
Chelonibia testudinaria
Bathylasma alearum
Bathylasma corolliforme
Conopea galeata
Conopea calceola
Conopea merrilli
Solidobalanus masignotus
Tetrapachylasma trigonum
Megalasma striatum
Octolasmis warwickii
Lysmata
Lysmata wurdemanni
Lysmata amboinensis
Lysmata californica
Lysmata bahia
Lysmata intermedia
Lysmata grabhami
Lysmata seticaudata
Lysmata nilita
Lysmata hochi
Lysmata nayaritensis
Lysmata rafa
Lysmata boggessi
Lysmata ankeri
Lysmata pederseni
Lysmata debelius
Lysmata galapaguensis
Lysmata cf. trisetacea
Insects
Icerya bimaculata
Icerya purchasi
Crypticerya zeteki
Annelida (Ringed worms)
Salvatoria clavata
Ophryotrocha gracilis
Ophryotrocha hartmanni
Ophryotrocha diadema
Ophryotrocha bacci
Ophryotrocha maculata
Ophryotrocha socialis
Chordata
Kryptolebias marmoratus
Serranus fasciatus
Serranus baldwini
Angiosperms (Flowering plants)
Some Acer (maple) species
Castilla elastica
Culcita macrocarpa
Datisca cannabina (false hemp)
Datisca glomerata (Durango root)
Fraxinus lanuginosa (Japanese ash)
Fraxinus ornus
Fuchsia microphylla
Gagea serotina
Mercurialis annua (Annual mercury)
Neobuxbaumia mezcalaensis
Nephelium lappaceum (Rambutan)
Panax trifolius (Ginseng)
Oxalis suksdorfii
Phillyrea angustifolia
Phillyrea latifolia
Ricinocarpos pinifolius
Sagittaria lancifolia (sub-androdioecy)
Saxifraga cernua
Schizopepon bryoniaefolius
Spinifex littoreus
Ulmus minor
See also
Gynodioecy
Plant sexuality
Dioecy
Trioecy
Hermaphrodite
Monoicy
References
External links
Diana Wolf. 'Breeding systems: Evolution of androdioecy'
Sex
Mating systems
Sexual system | Androdioecy | [
"Biology"
] | 1,890 | [
"Behavior",
"Sex",
"Sexual system",
"Mating systems",
"Mating"
] |
13,606,026 | https://en.wikipedia.org/wiki/Shell%20balance | In fluid mechanics, a shell balance can be used to determine the velocity profile of a moving fluid, i.e,. how fluid velocity changes with position across a flow cross section.
A "shell" is a differential element of the flow. By looking at the momentum and forces on one small portion, it is possible to integrate over the flow to see the larger picture of the flow as a whole. The balance is determining what goes into and out of the shell. Momentum is created within the shell through fluid entering and leaving the shell and by shear stress. In addition, there are pressure and gravitational forces on the shell. From this, it is possible to find a velocity for any point across the flow.
Applications
Shell balances can be used in many situations. For example, flow in a pipe, the flow of multiple fluids around each other, or flow due to pressure difference. Although terms in the shell balance and boundary conditions will change, the basic set up and process is the same.
Requirements for shell balance calculations
The fluid must exhibit:
Laminar flow
No bends or curves
Steady state
Two boundary conditions
Boundary Conditions are used to find constants of integration.
Fluid - Solid Boundary: No-slip condition, the velocity of a liquid at a solid is equal to the velocity of the solid.
Liquid - Gas Boundary: Shear stress = 0.
Liquid - Liquid Boundary: Equal velocity and shear stress on both liquids.
Performing shell balances
A fluid is flowing between and in contact with two horizontal surfaces of contact area A. A differential shell of height Δy is utilized (see diagram below).
The top surface is moving at velocity U and the bottom surface is stationary.
Density of fluid = ρ
Viscosity of fluid = μ
Velocity in x direction = , shown by the diagonal line above. This is what a shell balance is solving for.
Conservation of momentum
(Rate of momentum in) - (rate of momentum out) + (sum of all forces) = 0
To perform a shell balance, follow the following basic steps:
Find momentum from shear stress.(Momentum from Shear Stress Into System) - (Momentum from Shear Stress Out of System). Momentum from Shear Stress goes into the shell at y and leaves the system at y + Δy. Shear stress = τyx, area = A, momentum = τyxA.
Find momentum from the flow. Momentum flows into the system at x = 0 and out at x = L. The flow is steady state. Therefore, the momentum flow at x = 0 is equal to the moment of flow at x = L. Therefore, these cancel out.
Find gravity force on the shell.
Find pressure forces.
Plug into conservation of momentum and solve for τyx.
Apply Newton's law of viscosity for a Newtonian fluidτyx = -μ(dVx/dy).
Integrate to find the equation for velocity and use Boundary Conditions to find constants of integration.
Boundary 1: Top Surface: y = 0 and Vx = U
Boundary 2: Bottom Surface: y = D and Vx = 0
Resources
Fluid mechanics | Shell balance | [
"Engineering"
] | 624 | [
"Civil engineering",
"Fluid mechanics"
] |
13,606,227 | https://en.wikipedia.org/wiki/International%20Council%20for%20Industrial%20and%20Applied%20Mathematics | The International Council for Industrial and Applied Mathematics (ICIAM) is an organisation for professional applied mathematics societies and related organisations. The current president is Wil Schilders. The cash award for each of the prizes is 5000 USD.
History
Until 1999 the Council was known as the Committee for International Conferences on Industrial and Applied Mathematics (CICIAM). Formed in 1987 with the start of the ICIAM conference series, this committee represented the leaders of four applied mathematics societies: the Gesellschaft für Angewandte Mathematik und Mechanik (GAMM), in Germany, the Institute of Mathematics and its Applications (IMA), in England, the Society for Industrial and Applied Mathematics (SIAM), in the USA, and the Société de Mathématiques Appliquées et Industrielles (SMAI), in France. The first two presidents of the council, Roger Temam and Reinhard Mennicken, oversaw the addition of several other societies as members and associate members of the council; as of 2015 it had 21 full members and 26 associate members. Past Presidents include Olavi Nevanlinna, Ian Sloan, Rolf Jeltsch, Barbara Keyfitz, and María J. Esteban.
Congress
ICIAM organizes the four-yearly International Congress on Industrial and Applied Mathematics, the first of which was held in 1987. The most recent congress was in 2019 in Valencia (Spain), and the next will be in 2023 in Tokyo (Japan). It also sponsors several prizes, awarded at the congresses: the Lagrange Prize for exceptional career contributions, the Collatz Prize for outstanding applied mathematicians under the age of 42, the Pioneer Prize for applied mathematical work in a new field, the Maxwell Prize for originality in applied mathematics, and the Su Buchin Prize for outstanding contributions to emerging economies and human development.
Collatz Prize
The Collatz Prize is awarded by ICIAM every four years at the International Congress on Industrial and Applied Mathematics, to an applied mathematician under the age of 42. It was established in 1999 on the initiative of Gesellschaft für Angewandte Mathematik und Mechanik (GAMM), to recognize outstanding contributions in applied and industrial mathematics.
Named after the German mathematician Lothar Collatz, it is widely regarded as one of the most prestigious prizes for young applied mathematicians.
Prize Winners
1999 Stefan Müller
2003 E Weinan
2007 Felix Otto
2011 Emmanuel Candès
2015 Annalisa Buffa
2019 Siddhartha Mishra
2023 Maria Colombo
Lagrange Prize
The Lagrange Prize is awarded by ICIAM every four years at the International Congress on Industrial and Applied Mathematics, for lifetime achievement in applied mathematics. Named after Joseph-Louis Lagrange, it was established in 1999 on the initiative of Société de Mathématiques Appliquées et Industrielles (SMAI), Sociedad Española de Matemática Aplicada (SEMA) and Società Italiana di Matematica Applicata e Industriale (SIMAI).
Prize Winners
1999 Jacques-Louis Lions
2003
2007 Joseph Keller
2011 Alexandre Chorin
2015 Andrew Majda
2019 George C. Papanicolaou
2023 Alfio Quarteroni
Maxwell Prize
The Maxwell Prize is awarded by ICIAM every four years at the International Congress on Industrial and Applied Mathematics. Established in 1999 and named after James Clerk Maxwell, the prize provides international recognition to a mathematician who has demonstrated originality in applied mathematics. It was created on the initiative of the Institute of Mathematics and its Applications with the support of the James Clerk Maxwell Foundation.
Prize Winners
1999 Grigory Barenblatt
2003 Martin David Kruskal
2007
2011 Vladimir Rokhlin
2015 Jean-Michel Coron
2019 Claude Bardos
2023 Weinan E
Pioneer Prize
The Pioneer Prize is awarded by ICIAM every four years at the International Congress on Industrial and Applied Mathematics, for pioneering applied mathematical work in a new field. It was established in 1999 on the initiative of the Society for Industrial and Applied Mathematics (SIAM).
Prize Winners
1999 Ronald Coifman and
2003 Stanley Osher
2007 Ingrid Daubechies and Heinz Engl
2011 James Albert Sethian
2015 Björn Engquist
2019 Yvon Maday
Su Buchin Prize
The Su Buchin Prize is awarded by ICIAM every four years at the International Congress on Industrial and Applied Mathematics. Established in 2003 and named after the Chinese mathematician Su Buchin, the prize provides international recognition to outstanding contributions to applying mathematics to emerging economies and human development, including improving teaching and research. It was created on the initiative of the China Society for Industrial and Applied Mathematics (CSIAM), and was first awarded in 2007.
Prize Winners
2007 Gilbert Strang
2011 Edward Lungu
2015
2019 Giulia Di Nunno
Olga Taussky-Todd Lecture
An Olga Taussky-Todd Lecture has been held at each International Congress on Industrial and Applied Mathematics since 2007. Named after Olga Taussky-Todd, the lectureship is conferred upon an outstanding woman applied mathematician.
Olga Taussky-Todd Lecturers
2007 Pauline van den Driessche
2011 Beatrice Pelloni
2015 Éva Tardos
2019 Françoise Tisseur
References
External links
Official web site
Mathematical societies
Applied mathematics
Members of the International Science Council | International Council for Industrial and Applied Mathematics | [
"Mathematics"
] | 1,055 | [
"Applied mathematics"
] |
13,606,566 | https://en.wikipedia.org/wiki/Rotolock%20valve | A service valve is a valve used to separate one piece of equipment from another in any system where liquids or gases circulate. Two types of service valves are marketed: the Schrader-type valve and the stem-type service valve. Specialized versions are made for specific purposes, such as the Rotolock valve (a stem-type valve also called a Rotalock valve ), which is a special refrigeration valve with a teflon ring seated against a machined surface enclosed by a threaded fitting; this valve allows the technician to remove all refrigerant from the compressor without requiring removal of the system charge.
References
Valves
Heating, ventilation, and air conditioning | Rotolock valve | [
"Physics",
"Chemistry"
] | 140 | [
"Physical systems",
"Valves",
"Hydraulics",
"Piping"
] |
13,608,880 | https://en.wikipedia.org/wiki/Sands%20Atlantic%20City | Sands Atlantic City was a casino and hotel that operated from August 13, 1980 until November 11, 2006 in Atlantic City, New Jersey. It was formerly known as the Brighton Hotel & Casino. It consisted of a 21-story hotel tower with 532 rooms and a 5-story podium housing the casino, restaurants, shops, and various other amenities. It was adjacent to The Claridge Hotel and its parking garage was adjacent to the Madison Hotel.
History
Construction and opening
The first Brighton Hotel (originally named the Brighton Cottage) was opened in 1876 on the site that would eventually become the Sands. It was demolished in 1959.
The Brighton Hotel & Casino was built at a cost of $70 million by Greate Bay Casino Corporation, controlled by two local businessmen, Eugene Gatti and Arthur Kania. It opened on August 13, 1980. The Brighton was the fourth property to open following the 1977 legalization of casinos in Atlantic City, and the first to be built from the ground up, rather than as a renovation of an existing hotel. The developers hoped that the Brighton's quiet atmosphere and small size, about half that of the city's other casino hotels, would prove attractive to high rollers. Early marketing featured Bert Parks as a spokesman, and the slogan "Brighton Up".
After less than a month in operation, Holiday Inns agreed to buy the Brighton for $121 million in cash and stock plus assumption of the property's $37 million mortgage. Holiday Inns pulled out of the deal a month later. As the Brighton headed into its first winter, the city's low season, it faced severe cash flow problems, with lower monthly revenue than all its competitors.
Pratt era (1981–1998)
The Brighton was rescued in the first months of 1981 by $10 million in financing from Inns of the Americas (a Dallas-based hotel operator, owned by the Pratt brothers) and financiers Burton and Richard Koffman. Inns of the Americas and the Koffmans went on to buy a 60 percent interest in the Brighton from Gatti and Kania for $30 million in May 1981. Inns of the Americas had recently bought the Sands Hotel on the Las Vegas Strip, and immediately renamed the Atlantic City property under the well-known Sands name. The property soon became profitable under its new ownership.
The Pratts soon sold the Sands in Las Vegas back to its previous owner, but the Atlantic City property retained the Sands name under a licensing agreement, despite no longer having any affiliation with its namesake.
In 1982, arcade game manufacturer Williams Electronics began an effort to take over the Sands, buying Gatti and Kania's shares, and agreeing to buy the Koffmans' shares. A white knight soon appeared, in the form of Drew National Corp., a New York-based conglomerate, which agreed to buy the Koffmans' interest. The deal foundered when Drew's major shareholders, Robert Bass and his brothers, refused to make financial disclosures required by the gaming licensing process. A restructuring was eventually completed in 1985, with the Sands wholly owned by Pratt Hotel Corporation, which in turn was 52%-owned by Pratt's former shareholders, 35% by the Southmark Corporation of Texas, and 10% by Drew's shareholders.
At its peak, the Sands headlined top entertainers, such as Frank Sinatra, Tony Bennett, Cher, Liza Minnelli, Bob Dylan, Robin Williams, Whitney Houston, and Eddie Murphy, among others. However, Sands was soon eclipsed by newer Atlantic City casinos and, at the time of its closing, had become the smallest of the city's 12 casinos.
The Sands joined with the neighboring Claridge Hotel and Casino to build an elevated moving sidewalk, opened in 1988, to bring visitors from the boardwalk to the two properties.
Pratt Hotel announced plans in 1987 to build a sister property called the Sands Boardwalk at the site of the unfinished Penthouse Boardwalk Hotel and Casino, while the existing property would be renamed as the Sands Park. Later reports had the new property's name as the Hollywood Hotel and Casino, or the Sands Hollywood. The plan was scrapped when Penthouse instead sold the site to Donald Trump in March 1989.
The Sands took over the long vacant Jefferson Hotel, adjacent to its parking garage, in 1989, to be converted into administrative offices.
In the early 1990s, as legalized gambling spread to new states, the Pratts established Hollywood Casino Corp. (HWCC) to develop new casinos under the Hollywood Casino name. At the time of its initial public offering in 1993, HWCC owned an 80 percent stake in Pratt Hotel.
A second-floor gaming area was opened in 1994, with a ribbon-cutting by Governor Christie Whitman. The extra , including a new racebook, gave the Sands the fourth largest casino in Atlantic City.
The Sands announced a new plan in 1994 to rebrand itself as a Hollywood Casino within two years. A video store was opened at the property, along with the film-themed "Epic Buffet", decorated with props from classic movies. The rebranding was never completed.
As the Sands's high debt load and poor cash flow dragged down its parent company, HWCC decided in 1996 to divest itself of the property. At year's end, all of HWCC's stock in Pratt Hotel was distributed to HWCC shareholders, and Pratt Hotel was renamed as Greate Bay Casino Corporation.
Bankruptcy and Icahn era (1998–2006)
In 1998, the Sands filed for bankruptcy protection. While in bankruptcy, it was not required to make its $25 million in annual payments to bondholders, freeing up cash for a minor expansion. The Sands spent $10 million to buy the adjacent Midtown-Bala Hotel, which had separated it from Pacific Avenue, the main thoroughfare running parallel to the boardwalk. The Midtown-Bala was demolished to make way for a new entryway and porte-cochere, which were unveiled in June 2000.
Park Place Entertainment and financier Carl Icahn put forth competing plans to take over and reorganize the company. Icahn's plan was selected by the bankruptcy court, and the business was reorganized in September 2000 as the publicly traded GB Holdings Inc., with Icahn owning a 65 percent share. The Claridge also filed for bankruptcy in August 1999, and Icahn fought to gain control of it as well, hoping to combine its operations with those of the Sands, but Park Place instead won ownership of the Claridge and merged it into Bally's. Icahn later transferred most of the interest in the Sands to another of his companies, American Real Estate Partners, sending GB Holdings into bankruptcy in September 2005.
The Sands took over the adjacent historic Madison Hotel in 2000 under a lease agreement. By adding the Madison's units to its room count, the Sands was allowed to expand its casino floor by . The Sands spent $25 million on a renovation of the Madison, completed in 2005, turning the hotel's 230 rooms into 126 suites.
In May 2006, American Real Estate Partners purchased the vacant former site of the Traymore Hotel from Harrah's Entertainment for $61 million. The Traymore site separated the Sands from the boardwalk, which had always hampered the Sands's ability to expand, and reduced its attractiveness to potential buyers. Icahn indicated that he might use the Traymore site for an expansion of the Sands, or might bundle it together with the Sands for sale.
In September 2006, Pinnacle Entertainment agreed to buy the Sands and the Traymore site for a total of $250 million, with plans to close and demolish the Sands, and build a larger casino. The Sands closed on November 11, 2006, and the sale to Pinnacle was completed days later.
The building was imploded at 9:37 p.m. Eastern Daylight Time on October 18, 2007; the first-ever casino-hotel implosion on the East Coast. It was accompanied by a fireworks show and numerous parties along the boardwalk. Coincidentally, Sands was demolished less than 24 hours after the death of the last surviving member of the Rat Pack, comedian Joey Bishop.
Sands Atlantic City was the last casino in North America to bear the famous Sands moniker until the new Sands Casino Resort Bethlehem opened on May 22, 2009.
Pinnacle canceled its planned casino in 2010, and sold the land in 2013 for $29.5 million to a group of local developers who planned to build a casino or family entertainment attraction.
Facilities
As of 1999, the Sands's buildings had of floor space on of land, with facilities including:
a casino with 2,025 slot machines and 99 table games
a racebook
a 20-story tower with 532 hotel rooms, including deluxe "Plaza Club" rooms on the 17th through 19th floors
an 850-seat showroom
a two-story food court with eleven vendors
a spa and salon in the top two floors of the tower
an eleven-story parking garage with 1,738 spaces
administrative offices housed in the nine-story Jefferson Hotel building
a five-bay bus terminal
the People Mover, an elevated moving sidewalk, connecting the Sands and the Claridge to the boardwalk
Events
Boxing matches were held at the casino.
References
Defunct casinos in Atlantic City, New Jersey
Demolished hotels in New Jersey
Casinos completed in 1980
Hotel buildings completed in 1980
Hotels established in 1980
1980 establishments in New Jersey
2006 disestablishments in New Jersey
Buildings and structures demolished by controlled implosion
Boxing venues in Atlantic City, New Jersey
Skyscraper hotels in Atlantic City, New Jersey
Buildings and structures demolished in 2007
Casino hotels
Former skyscrapers | Sands Atlantic City | [
"Engineering"
] | 1,957 | [
"Buildings and structures demolished by controlled implosion",
"Architecture"
] |
13,609,180 | https://en.wikipedia.org/wiki/Hantzsch%20pyrrole%20synthesis | The Hantzsch Pyrrole Synthesis, named for Arthur Rudolf Hantzsch, is the chemical reaction of β-ketoesters (1) with ammonia (or primary amines) and α-haloketones (2) to give substituted pyrroles (3).
Pyrroles are found in a variety of natural products with biological activity, so the synthesis of substituted pyrroles has important applications in medicinal chemistry. Alternative methods for synthesizing pyrroles exist, such as the Knorr Pyrrole Synthesis and Paal-Knorr Synthesis.
Mechanism
Below is one published mechanism for the reaction:
The mechanism starts with the amine (1) attacking the β carbon of the β-ketoesters (2), and eventually forming an enamine (3). The enamine then attacks the carbonyl carbon of the α-haloketone (4). This is followed by the loss of H2O, giving an imine (5). This intermediate undergoes an intramolecular nucleophilic attack, forming a 5-membered ring (6). Finally, a hydrogen is eliminated and the pi-bonds are rearranged in the ring, yielding the final product (7).
An alternative mechanism has been proposed in which the enamine (3) attacks the α-carbon of the α-haloketone (4) as part of a nucleophilic substitution, instead of attacking the carbonyl carbon.
Generalized Reaction Under Mechanochemical Conditions
A generalization of the Hantzsch pyrrole synthesis was developed by Estevez, et al. In this reaction highly substituted pyrroles can be synthesized in a one-pot reaction, with relatively high yields (60% - 97%). This reaction involves the high-speed vibration milling (HSVM) of ketones with N-iodosuccinimide (NIS) and p-toluenesulfonic acid, to form an α-iodoketone in situ. This is followed by addition of a primary amine, a β-dicarbonyl compound, cerium(IV) ammonium nitrate (CAN) and silver nitrate, as shown in the scheme below:
Applications
2,3-dicarbonylated pyrroles
2,3-dicarbonylated pyrroles can be synthesized by a version of the Hantzsch Pyrrole Synthesis. These pyrroles are particularly useful for total synthesis because the carbonyl groups can be converted into a variety of other functional groups.
Substituted indoles
The reaction can also occur between an enamine and an α-haloketone to synthesize substituted indoles, which also have biological significance.
Continuous flow chemistry
A library of substituted pyrrole analogs can be quickly produced by using continuous flow chemistry (reaction times of around 8 min.). The advantage of using this method, as opposed to the in-flask synthesis, is that this one does not require the work-up and purification of several intermediates, and could therefore lead to a higher percent yield.
See also
Hantzsch pyridine synthesis
References
Pyrroles
Chemical synthesis
Name reactions | Hantzsch pyrrole synthesis | [
"Chemistry"
] | 664 | [
"Name reactions",
"nan",
"Chemical synthesis"
] |
13,609,261 | https://en.wikipedia.org/wiki/Astronomische%20Gesellschaft |
The Astronomische Gesellschaft is an astronomical society established in 1863 in Heidelberg, the second oldest astronomical society after the Royal Astronomical Society.
In 1882, the Astronomische Gesellschaft founded the Central Bureau for Astronomical Telegrams at Kiel, where it remained until during World War I when it was moved to the Østervold Observatory at Copenhagen, Denmark, to be operated there by the Copenhagen University Observatory.
Around the turn of the 20th century the A.G. initiated the most important star catalog of this time, the Astronomische Gesellschaft Katalog (AGK).
The assembly in Danzig (now Gdańsk) in August 1939 was the last until a meeting at Göttingen in 1947, when it was re-commenced as Astronomische Gesellschaft in der Britischen Zone. The post-war editorial board consisted of Chairman Albrecht Unsöld (Kiel), Otto Heckmann, J. Larink, B. Straßl, Paul ten Bruggencate, and also Max Beyer representing the amateurs of the society.
Presidents
1863–1864: Julius Zech
1864–1867: Friedrich Wilhelm Argelander
1867–1878: Otto Wilhelm von Struve
1878–1881: Adalbert Krueger
1881–1889: Arthur Auwers
1889–1896: Hugo Gyldén
1896–1921: Hugo von Seeliger
1921–1930: Svante Elis Strömgren
1930–1932: Max Wolf
1932–1939: Hans Ludendorff
1939–1945: August Kopff
1945–1947: vacant
1947–1949: Albrecht Unsöld
1949–1952: Friedrich Becker
1952–1957: Otto Heckmann
1957–1960: Paul ten Bruggencate
1960–1966: Hans Haffner
1966–1969: Rudolf Kippenhahn
1969–1972: Walter Fricke
1972–1975: Hans-Heinrich Voigt
1975–1978: Wolfgang Priester
1978–1981: Theodor Schmidt-Kaler
1981–1984: Gustav Andreas Tammann
1984–1987: Michael Grewing
1987–1990: Egon Horst Schröter
1990–1993: Wolfgang Hillebrandt
1993–1996: Hanns Ruder
1996–1999: Werner Pfau
1999–2002: Erwin Sedlmayr
2002–2005: Joachim Krautter
2005–2008: Gerhard Hensler
2008–2011: Ralf-Jürgen Dettmar
2011–2014: Andreas Burkert
2014–2017: Matthias Steinmetz
2017–2020: Joachim Wambsganß
since 2020: Michael Kramer
Honorary members
With dates of appointment:
Albrecht Unsöld (1989)
Wilhelm Becker (1992)
Erich Kirste (1992)
Martin Schwarzschild (1993)
Reimar Lüst (1998)
Hans-Heinrich Voigt (2007)
Klaus Tschira (2011)
Rudolf Kippenhahn (2016)
Awards
The astronomical society awards the following awards and prizes:
Karl Schwarzschild Medal
Ludwig Biermann Förderpreis (:de:Ludwig-Biermann-Förderpreis)
Bruno H. Bürgel Award
Hans Ludwig Neumann Award (:de:Hans-Ludwig-Neumann-Preis)
The Hanno and Ruth Roelin Prize is also awarded at the society's annual meeting, but it is administered by the Max Planck Institute for Astronomy.
See also
Astronomical Calculation Institute (University of Heidelberg)
Vereinigte Astronomische Gesellschaft
List of astronomical societies
References
Further reading
Schmeidler, F. 1988, Die Geschichte der Astronomischen Gesellschaft, Jubiläumsband - 125 Jahre Astronomische Gesellschaft, Astron. Ges. Hamburg, vi + 70pp.
Internationality from the VAG (1800) to the Astronomische Gesellschaft.
External links
Astronomy organizations
Astronomy in Germany
Scientific organisations based in Germany
1863 establishments in Baden
Scientific organizations established in 1863
Heidelberg | Astronomische Gesellschaft | [
"Astronomy"
] | 780 | [
"Astronomy organizations"
] |
13,609,399 | https://en.wikipedia.org/wiki/Least-squares%20spectral%20analysis | Least-squares spectral analysis (LSSA) is a method of estimating a frequency spectrum based on a least-squares fit of sinusoids to data samples, similar to Fourier analysis. Fourier analysis, the most used spectral method in science, generally boosts long-periodic noise in the long and gapped records; LSSA mitigates such problems. Unlike in Fourier analysis, data need not be equally spaced to use LSSA.
Developed in 1969 and 1971, LSSA is also known as the Vaníček method and the Gauss-Vaniček method after Petr Vaníček, and as the Lomb method or the Lomb–Scargle periodogram, based on the simplifications first by Nicholas R. Lomb and then by Jeffrey D. Scargle.
Historical background
The close connections between Fourier analysis, the periodogram, and the least-squares fitting of sinusoids have been known for a long time.
However, most developments are restricted to complete data sets of equally spaced samples. In 1963, Freek J. M. Barning of Mathematisch Centrum, Amsterdam, handled unequally spaced data by similar techniques, including both a periodogram analysis equivalent to what nowadays is called the Lomb method and least-squares fitting of selected frequencies of sinusoids determined from such periodograms — and connected by a procedure known today as the matching pursuit with post-back fitting or the orthogonal matching pursuit.
Petr Vaníček, a Canadian geophysicist and geodesist of the University of New Brunswick, proposed in 1969 also the matching-pursuit approach for equally and unequally spaced data, which he called "successive spectral analysis" and the result a "least-squares periodogram". He generalized this method to account for any systematic components beyond a simple mean, such as a "predicted linear (quadratic, exponential, ...) secular trend of unknown magnitude", and applied it to a variety of samples, in 1971.
Vaníček's strictly least-squares method was then simplified in 1976 by Nicholas R. Lomb of the University of Sydney, who pointed out its close connection to periodogram analysis. Subsequently, the definition of a periodogram of unequally spaced data was modified and analyzed by Jeffrey D. Scargle of NASA Ames Research Center, who showed that, with minor changes, it becomes identical to Lomb's least-squares formula for fitting individual sinusoid frequencies.
Scargle states that his paper "does not introduce a new detection technique, but instead studies the reliability and efficiency of detection with the most commonly used technique, the periodogram, in the case where the observation times are unevenly spaced," and further points out regarding least-squares fitting of sinusoids compared to periodogram analysis, that his paper "establishes, apparently for the first time, that (with the proposed modifications) these two methods are exactly equivalent."
Press summarizes the development this way:
In 1989, Michael J. Korenberg of Queen's University in Kingston, Ontario, developed the "fast orthogonal search" method of more quickly finding a near-optimal decomposition of spectra or other problems, similar to the technique that later became known as the orthogonal matching pursuit.
Development of LSSA and variants
The Vaníček method
In the Vaníček method, a discrete data set is approximated by a weighted sum of sinusoids of progressively determined frequencies using a standard linear regression or least-squares fit. The frequencies are chosen using a method similar to Barning's, but going further in optimizing the choice of each successive new frequency by picking the frequency that minimizes the residual after least-squares fitting (equivalent to the fitting technique now known as matching pursuit with pre-backfitting). The number of sinusoids must be less than or equal to the number of data samples (counting sines and cosines of the same frequency as separate sinusoids).
A data vector Φ is represented as a weighted sum of sinusoidal basis functions, tabulated in a matrix A by evaluating each function at the sample times, with weight vector x:
,
where the weights vector x is chosen to minimize the sum of squared errors in approximating Φ. The solution for x is closed-form, using standard linear regression:
Here the matrix A can be based on any set of functions mutually independent (not necessarily orthogonal) when evaluated at the sample times; functions used for spectral analysis are typically sines and cosines evenly distributed over the frequency range of interest. If we choose too many frequencies in a too-narrow frequency range, the functions will be insufficiently independent, the matrix ill-conditioned, and the resulting spectrum meaningless.
When the basis functions in A are orthogonal (that is, not correlated, meaning the columns have zero pair-wise dot products), the matrix ATA is diagonal; when the columns all have the same power (sum of squares of elements), then that matrix is an identity matrix times a constant, so the inversion is trivial. The latter is the case when the sample times are equally spaced and sinusoids chosen as sines and cosines equally spaced in pairs on the frequency interval 0 to a half cycle per sample (spaced by 1/N cycles per sample, omitting the sine phases at 0 and maximum frequency where they are identically zero). This case is known as the discrete Fourier transform, slightly rewritten in terms of measurements and coefficients.
— DFT case for N equally spaced samples and frequencies, within a scalar factor.
The Lomb method
Trying to lower the computational burden of the Vaníček method in 1976 (no longer an issue), Lomb proposed using the above simplification in general, except for pair-wise correlations between sine and cosine bases of the same frequency, since the correlations between pairs of sinusoids are often small, at least when they are not tightly spaced. This formulation is essentially that of the traditional periodogram but adapted for use with unevenly spaced samples. The vector x is a reasonably good estimate of an underlying spectrum, but since we ignore any correlations, Ax is no longer a good approximation to the signal, and the method is no longer a least-squares method — yet in the literature continues to be referred to as such.
Rather than just taking dot products of the data with sine and cosine waveforms directly, Scargle modified the standard periodogram formula so to find a time delay first, such that this pair of sinusoids would be mutually orthogonal at sample times and also adjusted for the potentially unequal powers of these two basis functions, to obtain a better estimate of the power at a frequency. This procedure made his modified periodogram method exactly equivalent to Lomb's method. Time delay by definition equals to
Then the periodogram at frequency is estimated as:
,
which, as Scargle reports, has the same statistical distribution as the periodogram in the evenly sampled case.
At any individual frequency , this method gives the same power as does a least-squares fit to sinusoids of that frequency and of the form:
In practice, it is always difficult to judge if a given Lomb peak is significant or not, especially when the nature of the noise is unknown, so for example a false-alarm spectral peak in the Lomb periodogram analysis of noisy periodic signal may result from noise in turbulence data. Fourier methods can also report false spectral peaks when analyzing patched-up or data edited otherwise.
The generalized Lomb–Scargle periodogram
The standard Lomb–Scargle periodogram is only valid for a model with a zero mean. Commonly, this is approximated — by subtracting the mean of the data before calculating the periodogram. However, this is an inaccurate assumption when the mean of the model (the fitted sinusoids) is non-zero. The generalized Lomb–Scargle periodogram removes this assumption and explicitly solves for the mean. In this case, the function fitted is
The generalized Lomb–Scargle periodogram has also been referred to in the literature as a floating mean periodogram.
Korenberg's "fast orthogonal search" method
Michael Korenberg of Queen's University in Kingston, Ontario, developed a method for choosing a sparse set of components from an over-complete set — such as sinusoidal components for spectral analysis — called the fast orthogonal search (FOS). Mathematically, FOS uses a slightly modified Cholesky decomposition in a mean-square error reduction (MSER) process, implemented as a sparse matrix inversion. As with the other LSSA methods, FOS avoids the major shortcoming of discrete Fourier analysis, so it can accurately identify embedded periodicities and excel with unequally spaced data. The fast orthogonal search method was also applied to other problems, such as nonlinear system identification.
Palmer's Chi-squared method
Palmer has developed a method for finding the best-fit function to any chosen number of harmonics, allowing more freedom to find non-sinusoidal harmonic functions.
His is a fast (FFT-based) technique for weighted least-squares analysis on arbitrarily spaced data with non-uniform standard errors. Source code that implements this technique is available.
Because data are often not sampled at uniformly spaced discrete times, this method "grids" the data by sparsely filling a time series array at the sample times. All intervening grid points receive zero statistical weight, equivalent to having infinite error bars at times between samples.
Applications
The most useful feature of LSSA is enabling incomplete records to be spectrally analyzed — without the need to manipulate data or to invent otherwise non-existent data.
Magnitudes in the LSSA spectrum depict the contribution of a frequency or period to the variance of the time series. Generally, spectral magnitudes thus defined enable the output's straightforward significance level regime. Alternatively, spectral magnitudes in the Vaníček spectrum can also be expressed in dB. Note that spectral magnitudes in the Vaníček spectrum follow β-distribution.
Inverse transformation of Vaníček's LSSA is possible, as is most easily seen by writing the forward transform as a matrix; the matrix inverse (when the matrix is not singular) or pseudo-inverse will then be an inverse transformation; the inverse will exactly match the original data if the chosen sinusoids are mutually independent at the sample points and their number is equal to the number of data points. No such inverse procedure is known for the periodogram method.
Implementation
The LSSA can be implemented in less than a page of MATLAB code. In essence:
"to compute the least-squares spectrum we must compute m spectral values ... which involves performing the least-squares approximation m times, each time to get [the spectral power] for a different frequency"
I.e., for each frequency in a desired set of frequencies, sine and cosine functions are evaluated at the times corresponding to the data samples, and dot products of the data vector with the sinusoid vectors are taken and appropriately normalized; following the method known as Lomb/Scargle periodogram, a time shift is calculated for each frequency to orthogonalize the sine and cosine components before the dot product; finally, a power is computed from those two amplitude components. This same process implements a discrete Fourier transform when the data are uniformly spaced in time and the frequencies chosen correspond to integer numbers of cycles over the finite data record.
This method treats each sinusoidal component independently, or out of context, even though they may not be orthogonal to data points; it is Vaníček's original method. In addition, it is possible to perform a full simultaneous or in-context least-squares fit by solving a matrix equation and partitioning the total data variance between the specified sinusoid frequencies. Such a matrix least-squares solution is natively available in MATLAB as the backslash operator.
Furthermore, the simultaneous or in-context method, as opposed to the independent or out-of-context version (as well as the periodogram version due to Lomb), cannot fit more components (sines and cosines) than there are data samples, so that:
Lomb's periodogram method, on the other hand, can use an arbitrarily high number of, or density of, frequency components, as in a standard periodogram; that is, the frequency domain can be over-sampled by an arbitrary factor. However, as mentioned above, one should keep in mind that Lomb's simplification and diverging from the least squares criterion opened up his technique to grave sources of errors, resulting even in false spectral peaks.
In Fourier analysis, such as the Fourier transform and discrete Fourier transform, the sinusoids fitted to data are all mutually orthogonal, so there is no distinction between the simple out-of-context dot-product-based projection onto basis functions versus an in-context simultaneous least-squares fit; that is, no matrix inversion is required to least-squares partition the variance between orthogonal sinusoids of different frequencies. In the past, Fourier's was for many a method of choice thanks to its processing-efficient fast Fourier transform implementation when complete data records with equally spaced samples are available, and they used the Fourier family of techniques to analyze gapped records as well, which, however, required manipulating and even inventing non-existent data just so to be able to run a Fourier-based algorithm.
See also
Non-uniform discrete Fourier transform
Orthogonal functions
SigSpec
Sinusoidal model
Spectral density
Spectral density estimation, for competing alternatives
References
External links
LSSA package freeware download, FORTRAN, Vaníček's least-squares spectral analysis method, from the University of New Brunswick.
LSWAVE package freeware download, MATLAB, includes the Vaníček's least-squares spectral analysis method, from the U.S. National Geodetic Survey.
Algorithms
Analysis of variance
Applied mathematics
Applied statistics
Carl Friedrich Gauss
Computational mathematics
Computational science
Data processing
Digital signal processing
Engineering statistics
Frequency
Frequency-domain analysis
Harmonic analysis
Iterative methods
Least squares
Linear algebra
Mathematical analysis
Mathematical optimization
Mathematical physics
Mathematics of computing
Multivariate statistics
Numerical analysis
Numerical linear algebra
Optimization algorithms and methods
Signal processing
Statistical forecasting
Statistical methods
Statistical signal processing
Stochastic processes
Theoretical computer science
Time series | Least-squares spectral analysis | [
"Physics",
"Mathematics",
"Technology",
"Engineering"
] | 2,950 | [
"Physical quantities",
"Computer engineering",
"Theoretical computer science",
"Linear algebra",
"Mathematical analysis",
"Applied mathematics",
"Mathematical logic",
"Computational science",
"Wikipedia categories named after physical quantities",
"Approximations",
"Algebra",
"Scalar physical ... |
13,609,521 | https://en.wikipedia.org/wiki/Hydnellum%20peckii | Hydnellum peckii is a fungus in the genus Hydnellum of the family Bankeraceae. It is a hydnoid species, producing spores on the surface of vertical spines or tooth-like projections that hang from the undersurface of the fruit bodies. It is found in North America, Europe, and was recently discovered in Iran (2008) and Korea (2010). Hydnellum peckii is a mycorrhizal species, and forms mutually beneficial relationships with a variety of coniferous trees, growing on the ground singly, scattered, or in fused masses.
The fruit bodies typically have a funnel-shaped cap with a white edge, although the shape can be highly variable. Young, moist fruit bodies can "bleed" bright red guttation droplets that contain a pigment known to have anticoagulant properties similar to heparin. The unusual appearance of the young fruit bodies has earned the species several descriptive common names, including strawberries and cream, the bleeding Hydnellum, the bleeding tooth fungus, the red-juice tooth, and the Devil's tooth. Although Hydnellum peckii fruit bodies are readily identifiable when young, they become brown and nondescript when they age.
Taxonomy
The species was first described scientifically by American mycologist Howard James Banker in 1913. Italian Pier Andrea Saccardo placed the species in the genus Hydnum in 1925, while Walter Henry Snell and Esther Amelia Dick placed it in Calodon in 1956; Hydnum peckii (Banker) Sacc. and Calodon peckii Snell & E.A. Dick are synonyms of Hydnellum peckii.
The fungus is classified in the stirps (species thought to be descendants of a common ancestor) Diabolum of the genus Hydnellum, a grouping of similar species with the following shared characteristics: flesh that is marked with concentric lines that form alternating pale and darker zones (zonate); an extremely peppery taste; a sweetish odor; spores that are ellipsoid, and not amyloid (that is, not absorbing iodine when stained with Melzer's reagent), acyanophilous (not staining with the reagent Cotton Blue), and covered with tubercules; the presence of clamp connections in the hyphae.
Etymology
The specific eponym honors mycologist Charles Horton Peck. The fungus is known in the vernacular by several names, including "strawberries and cream", the "bleeding Hydnellum", the "red-juice tooth", "Peck's hydnum", the "bleeding tooth fungus", and the "devil's tooth".
Description
As in all mushroom-producing fungi, the fruit bodies (sporocarps) are the reproductive structures that are produced from fungal mycelium when the appropriate environmental conditions of temperature, humidity and nutrient availability are met. Hydnellum peckii is a stipitate hydnoid fungus, meaning that it has a cap atop a stipe (stem), and a form resembling a Hydnum—characterized by a teeth-like hymenium, rather than gills or pores on the underside of the cap. Fruit bodies growing closely together often appear to fuse together (this is called "confluence"). They can reach a height of up to . Fresh fruit bodies exude a striking, thick red fluid when they are moist, present even in young specimens, which are lumplike in appearance.
The cap's surface is convex to flattened, more or less uneven and sometimes slightly depressed in the center. It is usually densely covered with "hairs" that give it a texture similar to felt or velvet; these hairs are sloughed off in age, leaving the caps of mature specimens smooth. Its shape varies from somewhat round to irregular, , or even as much as wide as a result of confluence. The cap is initially whitish, but later turns slightly brownish, with irregular dark-brown to nearly black blotches where it is bruised. In maturity, the surface is fibrous and tough, scaly and jagged, grayish brown in the upper part of the cap, and somewhat woody. The flesh is a pale pinkish brown. The spore print is brown.
The spines are slender, cylindrical and tapering (terete), less than long, and become shorter closer to the cap edge. They are crowded together, with typically between three and five teeth per square millimeter. Pinkish white initially, they age to a grayish brown. The stem is thick, very short, and often deformed. It becomes bulbous where it penetrates the ground, and may root into the soil for several centimeters. Although it may reach up to in total length, and is wide, only about appear above ground. The upper part is covered with the same teeth found on the underside of the cap, whereas the lower part is hairy and often encases debris from the forest floor. The odor of the fruit body has been described as "mild to disagreeable", or, as Banker suggested in his original description, similar to hickory nuts.
Microscopic features
In deposit, the spores appear brown. Viewing them with a light microscope reveals finer details of their structure: they are roughly spherical but end abruptly in a small point, their surfaces are covered with small, wart-like nodules, and their size is between 5.0–5.3 by 4.0–4.7 μm. The spores are inamyloid, meaning they do not absorb iodine when stained with Melzer's reagent.
Hydnellum peckii'''s cells (the hyphae) also present various characters useful for its characterization. The hyphae that form the cap are hyaline (translucent), smooth, thin-walled, and 3–4 μm thick. They collapse when dry, but may be readily revived with a weak (2%) solution of potassium hydroxide. Those in the cap form an intricate tangle with a tendency to run longitudinally. They are divided into cellular compartments (septa) and have clamp connections—short branches connecting one cell to the previous cell to allow passage of the products of nuclear division. The basidia, the spore-bearing cells in the hymenium, are club-shaped, four-spored, and measure 35–40 by 4.7–6 μm.
Similar speciesHydnellum diabolus (the species epithet is given the neuter diabolum in some publications) has a very similar appearance, so much so that some consider it and H. peckii to be synonymous; H. diabolus is said to have a sweetish pungent odor that is lacking in H. peckii. The differences between the two species are amplified in mature specimens: H. diabolus has an irregularly thickened stem, while the stem of H. peckii is thickened by a "definite spongy layer". Additionally, old specimens of H. peckii have a smooth cap, while H. diabolus is tomentose. The related species H. pineticola also exudes pink droplets of liquid when young and moist. Commonly found growing under conifers in northeastern North America, H. pineticola tastes "unpleasant", but not acrid. Fruit bodies tend to grow singly, rather than in fused clusters, and, unlike H. peckii, they do not have bulbous stems.
Molecular analysis based on the sequences of the internal transcribed spacer DNA of several Hydnellum species placed H. peckii as most closely related to H. ferrugineum and H. spongiosipes.Abortiporus biennis has no teeth but produces red droplets from exposed pores.
EcologyHydnellum peckii is a mycorrhizal fungus, and as such establishes a mutualistic relationship with the roots of certain trees (referred to as "hosts"), in which the fungus exchanges minerals and amino acids extracted from the soil for fixed carbon from the host. The subterranean hyphae of the fungus grow a sheath of tissue around the rootlets of a broad range of tree species, in an intimate association that is especially beneficial to the host (termed ectomycorrhizal), as the fungus produces enzymes that mineralize organic compounds and facilitate the transfer of nutrients to the tree.
The ectomycorrhizal structures of H. peckii are among a few in the Bankeraceae that have been studied in detail. They are characterized by a plectenchymatous mantle—a layer of tissue made of hyphae tightly arranged in a parallel orientation, or palisade, and which rarely branch or overlap each other. These hyphae, along with adhering mineral soil particles, are embedded in a gelatinous matrix. The hyphae of the ectomycorrhizae can become chlamydospores, an adaptation that helps the fungus tolerate unfavorable conditions. Chlamydospores of H. peckii have a peculiar structure—markedly distinct from those of other Bankeraceae—with thick, smooth inner walls and an outer wall that is split radially into warts. The most striking characteristic of the ectomycorrhizae as a whole is the way the black outer layers of older sections are shed, giving a "carbonized appearance". The majority of the underground biomass of the fungus is concentrated near the surface, most likely as "mycelial mats"—dense clusters of ectomycorrhizae and mycelium. The mycelium is also known to extend far beyond the site of the fruit bodies, as far as away.
Molecular techniques have been developed to help with conservation efforts of stipitate hydnoid fungi, including H. peckii. While the distribution of the fungus has traditionally been determined by counting the fruit bodies, this method has a major drawback in that fruit bodies are not produced consistently every year, and the absence of fruit bodies is not an indication of the absence of its mycelium in the soil. More modern techniques using the polymerase chain reaction to assess the presence of the fungal DNA in the soil have helped alleviate the issues in monitoring the presence and distribution of fungi mycelia.
Habitat and distribution
The fruit bodies of Hydnellum peckii are found growing solitary, scattered, or clustered together on the ground under conifers, often among mosses and pine needle litter. H. peckii is a "late-stage" fungus that, in boreal forests dominated by jack pine, typically begins associating with more mature hosts once the canopy has closed. A preference for mountainous or subalpine ecosystems has been noted.
The fungus has a wide distribution in North America, and is particularly common in the Pacific Northwest; its range extends north to Alaska and east to North Carolina. In the Puget Sound area of the U.S. state of Washington, it is found in association with Douglas-fir, fir, and hemlock. Along the Oregon Coast it has been collected under lodgepole pine. In addition to North America, the mushroom is widespread in Europe, and its presence has been documented in Italy, Germany, and Scotland. The species is common in the latter location, but becoming increasingly rare in several European countries, such as Norway, The Netherlands, and the Czech Republic. Increased pollution in central Europe has been suggested as one possible factor in the mushroom's decline there. Reports from Iran in 2008 and Korea in 2010 were the first outside Europe and North America.
Uses
Fruit bodies of H. peckii have been described as resembling "Danish pastry topped with strawberry jam". Hydnellum species are not known to be poisonous, but they are not particularly edible due to their foul taste. This acrid taste persists even in dried specimens.
The fruit bodies of this and other Hydnellum species are prized by mushroom dyers. The colors may range from beige when no mordant is used, to various shades of blue or green depending on the mordant added.
Chemistry
Screening of an extract of Hydnellum peckii revealed the presence of an effective anticoagulant, named atromentin (2,5-dihydroxy-3,6-bis(4-hydroxyphenyl)-1,4-benzoquinone), and similar in biological activity to the well-known anticoagulant heparin. Atromentin also possesses antibacterial activity, inhibiting the enzyme enoyl-acyl carrier protein reductase (essential for the biosynthesis of fatty acids) in the bacteria Streptococcus pneumoniae.Hydnellum peckii'' can bioaccumulate the metal caesium. In one Swedish field study, as much as 9% of the total caesium of the topmost of soil was found in the fungal mycelium. In general, ectomycorrhizal fungi, which grow most prolifically in the upper organic horizons of the soil or at the interface between the organic and mineral layers, are involved in the retention and cycling of caesium-137 in organic-rich forest soils.
References
External links
Inedible fungi
peckii
Fungi described in 1912
Fungi of North America
Fungi of Europe
Fungi of Asia
Fungi of Western Asia
Fungus species
Fungi used for fiber dyes | Hydnellum peckii | [
"Biology"
] | 2,766 | [
"Fungi",
"Fungus species"
] |
13,609,856 | https://en.wikipedia.org/wiki/Aircraft%20disinsection | Aircraft disinsection is the use of insecticide on international flights and in other closed spaces for insect and disease control. Confusion with disinfection, the elimination of microbes on surfaces, is not uncommon. Insect vectors of disease, mostly mosquitoes, have been introduced into and become indigenous in geographic areas where they were not previously present. Dengue, chikungunya and Zika spread across the Pacific and into the Americas by means of the airline networks. Cases of "airport malaria", in which live malaria-carrying mosquitoes disembark and infect people near the airport, may increase with global warming.
Definitions in the International Health Regulations (IHR) of the World Health Organization are:
"Disinfection" means the procedure whereby health measures are taken to control or kill infectious agents on a human or animal body surface or in or on baggage, cargo, containers, conveyances, goods and postal parcels by direct exposure to chemical or physical agents.
“Disinsection” means the procedure whereby health measures are taken to control or kill the insect vectors of human diseases present in baggage, cargo, containers, conveyances, goods and postal parcels.
Disinsection is mandated by the IHR. The WHO recommends d-phenothrin (2%) for space spraying and permethrin (2%) for residual disinsection. Neither is harmful when used as recommended, according to WHO. Disinsection is one of two applications of the IHR likely to be encountered by travelers; yellow fever vaccination is the other.
References
Aircraft operations
Pest control
Industrial hygiene | Aircraft disinsection | [
"Biology"
] | 327 | [
"Pests (organism)",
"Pest control"
] |
13,609,943 | https://en.wikipedia.org/wiki/SpaceOrb%20360 | The SpaceOrb 360 is a 6DOF computer input device that is designed to be operated with two hands. Each of the 6 axes have 10-bit precision each when measuring the amount of force or torque applied. It has two right-index-finger buttons and four right-thumb buttons. It interfaces with a computer through an RS-232 serial port using a custom binary protocol. Drivers for the device exist for Mac OS, Microsoft Windows and Linux. Logitech had similar 6DOF devices during the same time period called the Cyberman and Cyberman II.
The device was released in 1996, the same year as popular 3D games such as Descent II and Quake. It was originally called the Spaceball Avenger II, a sequel to SpaceTec's Spaceball Avenger. The SpaceOrb was especially suited for the gameplay of Descent because of the complete freedom-of-motion afforded by its rendering engine. There was strong support for the device in both Quake and Quake II, but the WASD-type keyboard-and-mouse controls eventually became more popular. As of the Half-Life engine (based on the original Quake source), there was specific support for the SpaceOrb's capabilities. Developers later started to drop variable movement speed support, which reduced the 10bit translation force measurement to 1bit per direction.
It was originally manufactured and sold by the SpaceTec IMC company (first bought by Labtec, which itself was later bought by Logitech). The device is no longer sold nor supported by Logitech. It has been supplanted by more modern devices sold under Logitech's 3Dconnexion brand, which are all one-handed 3DMice that afford the other hand the freedom to interact with the keyboard/mouse.
In 2009, a SpaceOrb fan with the username "vputz" has designed Arduino add ons (OrbDuino, OrbShield, Orbotron) to make SpaceOrbs available over USB, making it compatible with modern operating systems by emulating joystick, mouse, and/or keyboard.
ASCII Sphere 360
ASCII Entertainment (later Agetec) bought the SpaceOrb 360 design and technology license to manufacture the ASCII Sphere 360 model for the original Sony PlayStation.
References
External links
www.jaycrowe.com is Birdman's SpaceOrb Messageboard.
Hardware - ASCII Sphere 360 - Agetec, Inc. AGETEC ASCII Sphere 360 product page.
LGR Oddware: SpaceOrb 360 RealLife 3D Game Controller LGR Oddware: SpaceOrb 360 RealLife 3D Game Controller
Pointing devices
Computing input devices
History of human–computer interaction
Video game control methods | SpaceOrb 360 | [
"Technology"
] | 557 | [
"History of human–computer interaction",
"History of computing"
] |
13,611,339 | https://en.wikipedia.org/wiki/Sulfite%20process | The sulfite process produces wood pulp that is almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions. These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A variety of sulfite/bisulfite salts are used, including sodium (Na+), calcium (Ca2+), potassium (K+), magnesium (Mg2+), and ammonium (NH4+). The lignin is converted to lignosulfonates, which are soluble and can be separated from the cellulose fibers. For the production of cellulose, the sulfite process competes with the Kraft process which produces stronger fibers and is less environmentally costly.
History
The use of wood to make pulp for paper began with the development of mechanical pulping in the 1840s by Charles Fenerty in Nova Scotia and by F. G. Keller in Germany. Chemical processes quickly followed, first with Julius Roth's use of sulfurous acid to treat wood in 1857, followed by Benjamin Chew Tilghman's US patent on the use of calcium bisulfite, Ca(HSO3)2, to pulp wood in 1867. Almost a decade later in 1874 the first commercial sulfite pulp mill was built in Sweden. It used magnesium as the counter ion and was based on work by Carl Daniel Ekman.
By 1900 sulfite pulping had become the dominant means of producing wood pulp, surpassing mechanical pulping methods. The competing chemical pulping process, the sulfate or kraft process was developed by Carl F. Dahl in 1879 and the first kraft mill started (in Sweden) in 1890. The first sulphite mill in the United States was the Richmond Paper Company in Rumford, Rhode Island in the mid-1880s. The invention of the recovery boiler by G. H. Tomlinson in the early 1930s allowed kraft mills to recycle almost all of their pulping chemicals. This, along with the ability of the kraft process to accept a wider variety of types of wood and produce stronger fibers made the kraft process the dominant pulping process starting in the 1940s. Sulfite pulps now account for less than 10% of the total chemical pulp production and the number of sulfite mills continues to decrease.
Magnesium was the standard counter ion until calcium replaced it in the 1950s.
Pulping liquor preparation
The pulping liquor for most sulfite mills is generated by treating various bases (alkali metal or alkaline earth hydroxides) with sulfur dioxide:
SO2 + MOH → MHSO3
MHSO3 + MOH → M2SO3 + H2O
Similar reactions are effected with divalent cations (Mg2+, Ca2+) and using carbonates in place of hydroxide.
The ratio of sulfite to bisulfite depends on pH; above pH=7, sulfite predominates.
Calcium-based
The earliest process used calcium, obtained as inexpensive calcium carbonate, and there was little incentive to recover the inorganic materials. At least in Sweden the brown liquor from this process was previously frequently used for producing ethanol, while with other brown liquors the fermentable hexose sugars are left to contribute to the energy needed in the recovery process. Calcium sulfite, which is poorly soluble, converts to calcium bisulfite only at low pH. Therefore calcium-based sulfite processes require acidic conditions.
Ammonia-based
Ammonia-based processes do not allow recovery of the pulping chemicals since ammonia or ammonium salts are oxidized to nitrogen and nitrogen oxides when burned.
Magnesium-based
The recovery process used in magnesium-based sulfite pulping the "Magnefite" process is well developed. The concentrated brown liquor is burned in a recovery boiler, producing magnesium oxide and sulfur dioxide, both of which are recovered from the flue gases. Magnesium oxide is recovered in a wet scrubber to give a slurry of magnesium hydroxide.
MgO + H2O → Mg(OH)2
This magnesium hydroxide slurry is then used in another scrubber to absorb sulfur dioxide from the flue gases producing a magnesium bisulfite solution that is clarified, filtered and used as the pulping liquor.
Mg(OH)2 + 2 SO2 → Mg(HSO3)2
Sodium-based
Sodium-based processes use a recovery system similar to that used in the kraft recovery process, except that there is no "lime cycle".
Processes involved in sulfite pulping
The process is conducted in large pressure vessels called digesters. Sulfite pulping is carried out between pH 1.5 and 5. The pulp is in contact with the pulping chemicals for 4 to 14 hours and at temperatures ranging from 130 to 160 °C (266 to 320 °F), again depending on the chemicals used.
Most of the intermediates involved in delignification in sulfite pulping are resonance-stabilized carbocations formed either by protonation of carbon-carbon double bonds or acidic cleavage of ether bonds which connect many of the constituents of lignin. It is the latter reaction which is responsible for most lignin degradation in the sulfite process. The electrophilic carbocations react with bisulfite ions (HSO3−)to give sulfonates.
R-O-R' + H+ → R+ + R'OH
R+ + HSO3− → R-SO3H
The sulfite process does not degrade lignin to the same extent that the kraft process does and the lignosulfonates from the sulfite process are useful byproducts.
Chemical recovery
The spent cooking liquor from sulfite pulping is usually called brown liquor, but the terms red liquor, thick liquor and sulfite liquor are also used (compared to black liquor in the kraft process). Pulp washers, using countercurrent flow, remove the spent cooking chemicals and degraded lignin and hemicellulose. The extracted brown liquor is concentrated, in multiple effect evaporators. The concentrated brown liquor can be burned in the recovery boiler to generate steam and recover the inorganic chemicals for reuse in the pulping process or it can be neutralized to recover the useful byproducts of pulping. Recent developments in Chemrec's black liquor gasification process, adapting the technology to use in the sulfite pulping process, could make second generation biofuels production an alternative to the conventional recovery boiler technology. Around 1906 Gösta Ekström a Swedish engineer patented a process of ethanol generation from the residual 2-2.5% fermentable hexose sugars in the spent liquor.
The sulfite process can use calcium, ammonium, magnesium or sodium as a base.
Applications
The sulfite process is acidic and one of the drawbacks is that the acidic conditions hydrolyze some of the cellulose, which means that sulfite pulp fibers are not as strong as kraft pulp fibers. The yield of pulp (based on wood used) is higher than for kraft pulping and sulfite pulp is easier to bleach.
Commodity
Sulfite pulp remains an important commodity, especially for specialty papers and as a source of cellulose for non-paper applications. It is used to make fine paper, tissue, glassine, and to add strength to newsprint.
Dissolving pulp
A special grade of bleached sulfite pulp is known as dissolving pulp which is the raw material for a wide variety of cellulose derivatives, for example rayon, cellophane, cellulose acetate and methylcellulose.
Rayon is a reconstituted cellulose fiber used to make many fabrics.
Cellophane is a clear reconstituted cellulose film used in wrapping and windows in envelopes.
Cellulose acetate was used to make flexible films for photographic use, computer tapes and so on and also to make fibers.
Methylcellulose and other cellulose ether derivatives are used in a wide range of everyday products from adhesives to baked goods to pharmaceuticals.
Byproducts
Sulfite pulping is generally less destructive than kraft pulping, so there are more usable byproducts.
Lignosulfonates
Chief among sulfite process byproducts are lignosulfonates, which find a wide variety of uses where a relatively inexpensive agent is needed to make a water dispersion of a water-insoluble material. Lignosulfonates are used in tanning leather, making concrete, drilling mud, drywall and so on.
Oxidation of lignosulfonates was used to produce vanillin (artificial vanilla), and this process is still used by one supplier (Borregaard, Norway) while all North American production by this route ceased in the 1990s.
Other byproducts
Acid hydrolysis of hemicelluloses during sulfite pulping produces monosaccharides, predominantly mannose for softwoods and xylose for hardwoods, which can be fermented to produce ethanol.
See also
Pulp mill
References
Papermaking
Pulp and paper industry
Chemical processes | Sulfite process | [
"Chemistry"
] | 1,909 | [
"Chemical process engineering",
"Chemical processes",
"nan"
] |
13,612,177 | https://en.wikipedia.org/wiki/Outrunner | An outrunner is an electric motor having the rotor outside the stator, as though the motor were turned inside out. They are often used in radio-controlled model aircraft.
This type of motor spins its outer shell around its windings, much like motors found in ordinary CD-ROM computer drives. In fact, CD-ROM motors are frequently rewound into brushless outrunner motors for small park flyer aircraft. Parts to aid in converting CD-ROM motors to aircraft use are commercially available.
Usually, outrunners have more poles, so they spin much slower than their inrunner counterparts with their more traditional layout (though still considerably faster than ferrite motors, when compared with motors that use neodymium magnets) while producing far more torque. This makes an outrunner an excellent choice for directly driving electric aircraft propellers since they eliminate the extra weight, complexity, inefficiency and noise of a gearbox. Some front loading direct-drive washing machines use an outrunner motor.
Outrunner motors have quickly become popular and are now available in many sizes. They have also become popular in personal, electric transportation applications such as electric bikes and scooters due to their compact size and high efficiency.
Stator and magnetic pole count
The stationary (stator) windings of an outrunner motor are excited by conventional DC brushless motor controllers. A direct current (switched on and off at high frequency for voltage modulation) is typically passed through three or more non-adjacent windings together, and the group so energized is alternated electronically based upon rotor position feedback. The number of permanent magnets in the rotor does not match the number of stator poles, however. This is to reduce cogging torque and create a sinusoidal back emf. The number of magnet poles divided by 2 gives the ratio of magnetic field frequency to motor rotation frequency.
Common stator pole/magnet pole configurations
N denotes number of stator "wire wound" poles, P denotes number of rotor "permanent magnet" poles.
9N,12P - very common to many small outrunners. This is also the most common CD-ROM motor configuration. Winding Pattern is ABCABCABC
9N, 6P - Common for helicopter motor, EDFs, and other high speed applications. The winding pattern is ABCABCABC
12N, 14P (DLRK) - Common for higher torque applications. Noted commonly for its smooth and quiet operation. Winding Pattern is (lowercase implies reverse in winding direction).
Other configurations
9N, 8P - Magnetically imbalanced motor configuration occasionally found in high speed applications. This configuration is best terminated as WYE to minimize vibration.
9N, 10P - Highly magnetically imbalanced motor that often makes for noisy running. This configuration is usually only built by do it yourself motor builders. This motor is best terminated WYE. Winding pattern is
12N, 16P - A not so common but still used style. It has been overshadowed by the 12N, 14P. Winding pattern is ABCABCABCABC
12N, 10P - Higher speed variant of the DLRK motor. Occasionally found in helicopter motors. Winding Pattern is (lowercase implies reverse in winding direction).
12N, 8P - Even higher speed than the 12N, 10P. Winding pattern is ABCABCABCABC
See also
Inrunner
References
External links
Brushless, outrunner-type electric motor schematics and info
Radio control
Radio-controlled aircraft
Electric motors
Electric aircraft | Outrunner | [
"Technology",
"Engineering"
] | 715 | [
"Electrical engineering",
"Engines",
"Electric motors"
] |
13,612,232 | https://en.wikipedia.org/wiki/Amelioration%20pattern | In software engineering, an amelioration pattern is an anti-pattern formed when an existing software design pattern was edited (i.e. rearranged, added or deleted) to better suit a particular problem so as to achieve some further effect or behavior. In this sense, an amelioration pattern is transformational in character.
References
External links
Amelioration Pattern at the Portland Pattern Repository
Software design patterns | Amelioration pattern | [
"Technology",
"Engineering"
] | 84 | [
"Software engineering",
"Anti-patterns",
"Software engineering stubs"
] |
13,612,261 | https://en.wikipedia.org/wiki/Inrunner | The term inrunner refers to an electric motor where the rotor (runner) is inside the stator. The term is in particular used for brushless motors to differentiate them from outrunners that have their rotor outside the stator. The vast majority of electric motors are inrunners.
Usage in drones and model aircraft
Compared to outrunner motors, inrunners tend to spin exceptionally fast, often as high as 11 000 r/min per volt, far too fast for most aircraft propellers. However, inrunners lack torque. As a result, most inrunners are used in conjunction with a gearbox in both surface and aircraft models to reduce speed and increase torque
In many cases the inrunner is "ironless" in that there is no iron stator core to magnetize. The wire is run inside the can and held in place by epoxy or other resin material. Because there is no magnetic iron core, ironless in runners have no cogging, in that they spin freely with no magnetic interaction when power is disconnected. A well-designed ironless inrunner is extremely efficient. This is because there is virtually no iron magnetization loss and very little windage loss in the motor. However, due to the lack of a magnetic stator core, the ironless motor has very low torque but also higher motor velocity constant (Kv, a unit that is defined as r/min per volt) when compared to an iron core motor.
Modern brushless inrunners can have iron core windings to address the lack of torque while maintaining high r/min capability, more commonly used in radio-controlled car and truck applications
See also
Outrunner
Radio-controlled aircraft
Radio-controlled cars
Electric motors | Inrunner | [
"Technology",
"Engineering"
] | 347 | [
"Electrical engineering",
"Engines",
"Electric motors"
] |
13,612,376 | https://en.wikipedia.org/wiki/Shade%20sail | A shade sail − or somewhat more precise a textile sunshade sail or a textile sun protection sail − is a device to create outdoor shade based on the textile basic technology that can be found in a ship's sail. Shade sails use a flexible membrane tensioned between several anchor points. While generally installed permanently, they are cheap and easy to set up. They are usually provided above public gathering places such as seating areas and playgrounds in countries where strong sun radiation makes prolonged stays in the open sun unpleasant or dangerous due to sunburn and skin cancer risk.
History
Ancient Egyptians and later the Greeks and Romans used large pieces of fabric to provide shade. The Colosseum in Rome was shaded with large canvas "sails" pulled into place by Roman sailors. Modern shade sails came into wider use with the invention of a far more durable and relatively inexpensive fabric called shade cloth. Useful versions of shade cloth appeared in the early 1990s especially in Australia and South Africa.
For most of the 1990s there was some confusion about what these new devices should be called however they are now most commonly called shade sails throughout Australia, South Africa and the U.S.A. Shade sails have yet to have a significant impact in Europe and South America . A number of Australian shade sail businesses export to other countries. Rapid growth in the "shade sail industry" has seen many new businesses and websites offering shade sails and shade structures.
Current technology
Originally shade fabric, like all fabrics in the outdoors, suffered from UV degradation. UV inhibitors are now added during the manufacture of shade cloth and good shade cloth now generally comes with a multi-year UV degradation warranties. Shade cloth is a knitted fabric and this is an important factor in using it to design and manufacture shade sails. Shade fabrics are measured by their shade factor, which is the measure of how much a shade fabric absorbs or reflects invisible light (ultraviolet radiation). This is listed as a percentage out of 100, with a 100% shade factor indicating complete light blockage.
Successful shade sail design uses the inherent "stretch" of the knitted fabric to create three-dimensional shapes. Fabrics other than shade cloth are used to make shade sails such as PVC, a more expensive alternative, or canvas variations. The low cost of shade cloth and its ability to breathe makes it a prime choice for "cool shade".
Installation
Modern purpose-made shade sails vary in shape, size and color and there is trend towards installing multiple sails, sometimes overlapping, thereby adding some form and style to its function. Shade sails are tensioned usually by means of either a stainless steel turnbuckle or a pulley system fixed at each corner of the sail. For permanently fixed sails, the turnbuckle provides the best means of fixing the canopy since it generally allows more tension to be applied. For sails that are used on an occasional basis, the pulley system is more practical since it can be set up and taken down in a couple of minutes.
For domestic applications of shade sails it is recommended to install them with a quick release "snap hook" at each corner. This allows the sail shade to be quickly taken down in high wind conditions or during the winter season. Correct installation requires that adequate and quite considerable tension be applied to the sail to allow it to adopt its correct shape and prevent flapping in the wind. It is important to ensure that the mounting points are substantial and secure both to be able to accept the required initial tension and to absorb the loads created by wind gusts hitting the sail.
References
2. "What is a shade sail - Shadeg". shadeg.co.za.
Architectural elements
Tensile membrane structures | Shade sail | [
"Technology",
"Engineering"
] | 734 | [
"Building engineering",
"Architectural elements",
"Components",
"Architecture"
] |
13,612,447 | https://en.wikipedia.org/wiki/Repeating%20decimal | A repeating decimal or recurring decimal is a decimal representation of a number whose digits are eventually periodic (that is, after some place, the same sequence of digits is repeated forever); if this sequence consists only of zeros (that is if there is only a finite number of nonzero digits), the decimal is said to be terminating, and is not considered as repeating.
It can be shown that a number is rational if and only if its decimal representation is repeating or terminating. For example, the decimal representation of becomes periodic just after the decimal point, repeating the single digit "3" forever, i.e. 0.333.... A more complicated example is , whose decimal becomes periodic at the second digit following the decimal point and then repeats the sequence "144" forever, i.e. 5.8144144144.... Another example of this is , which becomes periodic after the decimal point, repeating the 13-digit pattern "1886792452830" forever, i.e. 11.18867924528301886792452830....
The infinitely repeated digit sequence is called the repetend or reptend. If the repetend is a zero, this decimal representation is called a terminating decimal rather than a repeating decimal, since the zeros can be omitted and the decimal terminates before these zeros. Every terminating decimal representation can be written as a decimal fraction, a fraction whose denominator is a power of 10 (e.g. ); it may also be written as a ratio of the form (e.g. ). However, every number with a terminating decimal representation also trivially has a second, alternative representation as a repeating decimal whose repetend is the digit 9. This is obtained by decreasing the final (rightmost) non-zero digit by one and appending a repetend of 9. Two examples of this are and . (This type of repeating decimal can be obtained by long division if one uses a modified form of the usual division algorithm.)
Any number that cannot be expressed as a ratio of two integers is said to be irrational. Their decimal representation neither terminates nor infinitely repeats, but extends forever without repetition (see ). Examples of such irrational numbers are and .
Background
Notation
There are several notational conventions for representing repeating decimals. None of them are accepted universally.
Vinculum: In the United States, Canada, India, France, Germany, Italy, Switzerland, the Czech Republic, Slovakia, Slovenia, Chile, and Turkey, the convention is to draw a horizontal line (a vinculum) above the repetend.
Dots: In some Islamic countries, such as Malaysia, Morocco, Pakistan, Tunisia, Iran, Algeria and Egypt, as well as the United Kingdom, New Zealand, Australia, South Africa, Japan, Thailand, India, South Korea, Singapore, and the People's Republic of China, the convention is to place dots above the outermost numerals of the repetend.
Parentheses: In parts of Europe, incl. Austria, Denmark, Finland, the Netherlands, Norway, Poland, Russia and Ukraine, as well as Vietnam and Israel, the convention is to enclose the repetend in parentheses. This can cause confusion with the notation for standard uncertainty.
Arc: In Spain and some Latin American countries, such as Argentina, Brazil, and Mexico, the arc notation over the repetend is also used as an alternative to the vinculum and the dots notation.
Ellipsis: Informally, repeating decimals are often represented by an ellipsis (three periods, 0.333...), especially when the previous notational conventions are first taught in school. This notation introduces uncertainty as to which digits should be repeated and even whether repetition is occurring at all, since such ellipses are also employed for irrational numbers; , for example, can be represented as 3.14159....
In English, there are various ways to read repeating decimals aloud. For example, 1.2 may be read "one point two repeating three four", "one point two repeated three four", "one point two recurring three four", "one point two repetend three four" or "one point two into infinity three four". Likewise, 11. may be read "eleven point repeating one double eight six seven nine two four five two eight three zero", "eleven point repeated one double eight six seven nine two four five two eight three zero", "eleven point recurring one double eight six seven nine two four five two eight three zero" "eleven point repetend one double eight six seven nine two four five two eight three zero" or "eleven point into infinity one double eight six seven nine two four five two eight three zero".
Decimal expansion and recurrence sequence
In order to convert a rational number represented as a fraction into decimal form, one may use long division. For example, consider the rational number :
0.0
74 ) 5.00000
4.44
560
518
420
370
500
etc. Observe that at each step we have a remainder; the successive remainders displayed above are 56, 42, 50. When we arrive at 50 as the remainder, and bring down the "0", we find ourselves dividing 500 by 74, which is the same problem we began with. Therefore, the decimal repeats: ....
For any integer fraction , the remainder at step k, for any positive integer k, is A × 10k (modulo B).
Every rational number is either a terminating or repeating decimal
For any given divisor, only finitely many different remainders can occur. In the example above, the 74 possible remainders are 0, 1, 2, ..., 73. If at any point in the division the remainder is 0, the expansion terminates at that point. Then the length of the repetend, also called "period", is defined to be 0.
If 0 never occurs as a remainder, then the division process continues forever, and eventually, a remainder must occur that has occurred before. The next step in the division will yield the same new digit in the quotient, and the same new remainder, as the previous time the remainder was the same. Therefore, the following division will repeat the same results. The repeating sequence of digits is called "repetend" which has a certain length greater than 0, also called "period".
In base 10, a fraction has a repeating decimal if and only if in lowest terms, its denominator has any prime factors besides 2 or 5, or in other words, cannot be expressed as 2m 5n, where m and n are non-negative integers.
Every repeating or terminating decimal is a rational number
Each repeating decimal number satisfies a linear equation with integer coefficients, and its unique solution is a rational number. In the example above, satisfies the equation
{|
| nowrap="" |10000α − 10α
| nowrap="" |= 58144.144144... − 58.144144...
|-
| align="right" |9990α || = 58086
|-
| align="right" |Therefore, α || = =
|}
The process of how to find these integer coefficients is described below.
Formal proof
Given a repeating decimal where , , and are groups of digits, let , the number of digits of . Multiplying by separates the repeating and terminating groups:
If the decimals terminate (), the proof is complete. For with digits, let where is a terminating group of digits. Then,
where denotes the i-th digit, and
Since ,
Since is the sum of an integer () and a rational number (), is also rational.
Table of values
Thereby fraction is the unit fraction and ℓ10 is the length of the (decimal) repetend.
The lengths ℓ10(n) of the decimal repetends of , n = 1, 2, 3, ..., are:
0, 0, 1, 0, 0, 1, 6, 0, 1, 0, 2, 1, 6, 6, 1, 0, 16, 1, 18, 0, 6, 2, 22, 1, 0, 6, 3, 6, 28, 1, 15, 0, 2, 16, 6, 1, 3, 18, 6, 0, 5, 6, 21, 2, 1, 22, 46, 1, 42, 0, 16, 6, 13, 3, 2, 6, 18, 28, 58, 1, 60, 15, 6, 0, 6, 2, 33, 16, 22, 6, 35, 1, 8, 3, 1, 18, 6, 6, 13, 0, 9, 5, 41, 6, 16, 21, 28, 2, 44, 1, 6, 22, 15, 46, 18, 1, 96, 42, 2, 0... .
For comparison, the lengths ℓ2(n) of the binary repetends of the fractions , n = 1, 2, 3, ..., are:
0, 0, 2, 0, 4, 2, 3, 0, 6, 4, 10, 2, 12, 3, 4, 0, 8, 6, 18, 4, 6, 10, 11, 2, 20, 12, 18, 3, 28, 4, 5, 0, 10, 8, 12, 6, 36, 18, 12, 4, 20, 6, 14, 10, 12, 11, ... (=[n], if n not a power of 2 else =0).
The decimal repetends of , n = 1, 2, 3, ..., are:
0, 0, 3, 0, 0, 6, 142857, 0, 1, 0, 09, 3, 076923, 714285, 6, 0, 0588235294117647, 5, 052631578947368421, 0, 047619, 45, 0434782608695652173913, 6, 0, 384615, 037, 571428, 0344827586206896551724137931, 3, 032258064516129, 0, 03, 2941176470588235, 285714... .
The decimal repetend lengths of , p = 2, 3, 5, ... (nth prime), are:
0, 1, 0, 6, 2, 6, 16, 18, 22, 28, 15, 3, 5, 21, 46, 13, 58, 60, 33, 35, 8, 13, 41, 44, 96, 4, 34, 53, 108, 112, 42, 130, 8, 46, 148, 75, 78, 81, 166, 43, 178, 180, 95, 192, 98, 99, 30, 222, 113, 228, 232, 7, 30, 50, 256, 262, 268, 5, 69, 28, 141, 146, 153, 155, 312, 79... .
The least primes p for which has decimal repetend length n, n = 1, 2, 3, ..., are:
3, 11, 37, 101, 41, 7, 239, 73, 333667, 9091, 21649, 9901, 53, 909091, 31, 17, 2071723, 19, 1111111111111111111, 3541, 43, 23, 11111111111111111111111, 99990001, 21401, 859, 757, 29, 3191, 211, 2791, 353, 67, 103, 71, 999999000001, 2028119, 909090909090909091, 900900900900990990990991, 1676321, 83, 127, 173... .
The least primes p for which has n different cycles (), n = 1, 2, 3, ..., are:
7, 3, 103, 53, 11, 79, 211, 41, 73, 281, 353, 37, 2393, 449, 3061, 1889, 137, 2467, 16189, 641, 3109, 4973, 11087, 1321, 101, 7151, 7669, 757, 38629, 1231, 49663, 12289, 859, 239, 27581, 9613, 18131, 13757, 33931... .
Fractions with prime denominators
A fraction in lowest terms with a prime denominator other than 2 or 5 (i.e. coprime to 10) always produces a repeating decimal. The length of the repetend (period of the repeating decimal segment) of is equal to the order of 10 modulo p. If 10 is a primitive root modulo p, then the repetend length is equal to p − 1; if not, then the repetend length is a factor of p − 1. This result can be deduced from Fermat's little theorem, which states that .
The base-10 digital root of the repetend of the reciprocal of any prime number greater than 5 is 9.
If the repetend length of for prime p is equal to p − 1 then the repetend, expressed as an integer, is called a cyclic number.
Cyclic numbers
Examples of fractions belonging to this group are:
= 0., 6 repeating digits
= 0., 16 repeating digits
= 0., 18 repeating digits
= 0., 22 repeating digits
= 0., 28 repeating digits
= 0., 46 repeating digits
= 0., 58 repeating digits
= 0., 60 repeating digits
= 0., 96 repeating digits
The list can go on to include the fractions , , , , , , , , , , etc. .
Every proper multiple of a cyclic number (that is, a multiple having the same number of digits) is a rotation:
= 1 × 0. = 0.
= 2 × 0. = 0.
= 3 × 0. = 0.
= 4 × 0. = 0.
= 5 × 0. = 0.
= 6 × 0. = 0.
The reason for the cyclic behavior is apparent from an arithmetic exercise of long division of : the sequential remainders are the cyclic sequence . See also the article 142,857 for more properties of this cyclic number.
A fraction which is cyclic thus has a recurring decimal of even length that divides into two sequences in nines' complement form. For example starts '142' and is followed by '857' while (by rotation) starts '857' followed by its nines' complement '142'.
The rotation of the repetend of a cyclic number always happens in such a way that each successive repetend is a bigger number than the previous one. In the succession above, for instance, we see that 0.142857... < 0.285714... < 0.428571... < 0.571428... < 0.714285... < 0.857142.... This, for cyclic fractions with long repetends, allows us to easily predict what the result of multiplying the fraction by any natural number n will be, as long as the repetend is known.
A proper prime is a prime p which ends in the digit 1 in base 10 and whose reciprocal in base 10 has a repetend with length p − 1. In such primes, each digit 0, 1,..., 9 appears in the repeating sequence the same number of times as does each other digit (namely, times). They are:
61, 131, 181, 461, 491, 541, 571, 701, 811, 821, 941, 971, 1021, 1051, 1091, 1171, 1181, 1291, 1301, 1349, 1381, 1531, 1571, 1621, 1741, 1811, 1829, 1861,... .
A prime is a proper prime if and only if it is a full reptend prime and congruent to 1 mod 10.
If a prime p is both full reptend prime and safe prime, then will produce a stream of p − 1 pseudo-random digits. Those primes are
7, 23, 47, 59, 167, 179, 263, 383, 503, 863, 887, 983, 1019, 1367, 1487, 1619, 1823, 2063... .
Other reciprocals of primes
Some reciprocals of primes that do not generate cyclic numbers are:
= 0., which has a period (repetend length) of 1.
= 0., which has a period of two.
= 0., which has a period of six.
= 0., which has a period of 15.
= 0., which has a period of three.
= 0., which has a period of five.
= 0., which has a period of 21.
= 0., which has a period of 13.
= 0., which has a period of 33.
= 0., which has a period of 35.
= 0., which has a period of eight.
= 0., which has a period of 13.
= 0., which has a period of 41.
= 0., which has a period of 44.
The reason is that 3 is a divisor of 9, 11 is a divisor of 99, 41 is a divisor of 99999, etc.
To find the period of , we can check whether the prime p divides some number 999...999 in which the number of digits divides p − 1. Since the period is never greater than p − 1, we can obtain this by calculating . For example, for 11 we get
and then by inspection find the repetend 09 and period of 2.
Those reciprocals of primes can be associated with several sequences of repeating decimals. For example, the multiples of can be divided into two sets, with different repetends. The first set is:
= 0.
= 0.
= 0.
= 0.
= 0.
= 0.
where the repetend of each fraction is a cyclic re-arrangement of 076923. The second set is:
= 0.
= 0.
= 0.
= 0.
= 0.
= 0.
where the repetend of each fraction is a cyclic re-arrangement of 153846.
In general, the set of proper multiples of reciprocals of a prime p consists of n subsets, each with repetend length k, where nk = p − 1.
Totient rule
For an arbitrary integer n, the length L(n) of the decimal repetend of divides φ(n), where φ is the totient function. The length is equal to if and only if 10 is a primitive root modulo n.
In particular, it follows that if and only if p is a prime and 10 is a primitive root modulo p. Then, the decimal expansions of for n = 1, 2, ..., p − 1, all have period p − 1 and differ only by a cyclic permutation. Such numbers p are called full repetend primes.
Reciprocals of composite integers coprime to 10
If p is a prime other than 2 or 5, the decimal representation of the fraction repeats:
= 0..
The period (repetend length) L(49) must be a factor of λ(49) = 42, where λ(n) is known as the Carmichael function. This follows from Carmichael's theorem which states that if n is a positive integer then λ(n) is the smallest integer m such that
for every integer a that is coprime to n.
The period of is usually pTp, where Tp is the period of . There are three known primes for which this is not true, and for those the period of is the same as the period of because p2 divides 10p−1−1. These three primes are 3, 487, and 56598313 .
Similarly, the period of is usually pk–1Tp
If p and q are primes other than 2 or 5, the decimal representation of the fraction repeats. An example is :
119 = 7 × 17
λ(7 × 17) = LCM(λ(7), λ(17)) = LCM(6, 16) = 48,
where LCM denotes the least common multiple.
The period T of is a factor of λ(pq) and it happens to be 48 in this case:
= 0..
The period T of is LCM(Tp, Tq), where Tp is the period of and Tq is the period of .
If p, q, r, etc. are primes other than 2 or 5, and k, ℓ, m, etc. are positive integers, then
is a repeating decimal with a period of
where Tpk, Tqℓ, Trm,... are respectively the period of the repeating decimals , , ,... as defined above.
Reciprocals of integers not coprime to 10
An integer that is not coprime to 10 but has a prime factor other than 2 or 5 has a reciprocal that is eventually periodic, but with a non-repeating sequence of digits that precede the repeating part. The reciprocal can be expressed as:
where a and b are not both zero.
This fraction can also be expressed as:
if a > b, or as
if b > a, or as
if a = b.
The decimal has:
An initial transient of max(a, b) digits after the decimal point. Some or all of the digits in the transient can be zeros.
A subsequent repetend which is the same as that for the fraction .
For example = 0.03:
a = 2, b = 0, and the other factors
there are 2 initial non-repeating digits, 03; and
there are 6 repeating digits, 571428, the same amount as has.
Converting repeating decimals to fractions
Given a repeating decimal, it is possible to calculate the fraction that produces it. For example:
{|
|-
|style="text-align:right;width:3em"| ||style="width:12em"|
|-
|style="text-align:right"| || || (multiply each side of the above line by 10)
|-
|style="text-align:right"| || || (subtract the 1st line from the 2nd)
|-
|style="text-align:right"| || || (reduce to lowest terms)
|}
Another example:
{|
|-
|style="text-align:right;width:3em"| ||style="width:12em"|
|-
|style="text-align:right"| || || (move decimal to start of repetition = move by 1 place = multiply by 10)
|-
|style="text-align:right"| || || (collate 2nd repetition here with 1st above = move by 2 places = multiply by 100)
|-
|style="text-align:right"| || || (subtract to clear decimals)
|-
|style="text-align:right"| || || (reduce to lowest terms)
|}
A shortcut
The procedure below can be applied in particular if the repetend has n digits, all of which are 0 except the final one which is 1. For instance for n = 7:
So this particular repeating decimal corresponds to the fraction , where the denominator is the number written as n 9s. Knowing just that, a general repeating decimal can be expressed as a fraction without having to solve an equation. For example, one could reason:
or
It is possible to get a general formula expressing a repeating decimal with an n-digit period (repetend length), beginning right after the decimal point, as a fraction:
More explicitly, one gets the following cases:
If the repeating decimal is between 0 and 1, and the repeating block is n digits long, first occurring right after the decimal point, then the fraction (not necessarily reduced) will be the integer number represented by the n-digit block divided by the one represented by n 9s. For example,
0.444444... = since the repeating block is 4 (a 1-digit block),
0.565656... = since the repeating block is 56 (a 2-digit block),
0.012012... = since the repeating block is 012 (a 3-digit block); this further reduces to .
0.999999... = = 1, since the repeating block is 9 (also a 1-digit block)
If the repeating decimal is as above, except that there are k (extra) digits 0 between the decimal point and the repeating n-digit block, then one can simply add k digits 0 after the n digits 9 of the denominator (and, as before, the fraction may subsequently be simplified). For example,
0.000444... = since the repeating block is 4 and this block is preceded by 3 zeros,
0.005656... = since the repeating block is 56 and it is preceded by 2 zeros,
0.00012012... = = since the repeating block is 012 and it is preceded by 2 zeros.
Any repeating decimal not of the form described above can be written as a sum of a terminating decimal and a repeating decimal of one of the two above types (actually the first type suffices, but that could require the terminating decimal to be negative). For example,
1.23444... = 1.23 + 0.00444... = + = + =
or alternatively 1.23444... = 0.79 + 0.44444... = + = + =
0.3789789... = 0.3 + 0.0789789... = + = + = =
or alternatively 0.3789789... = −0.6 + 0.9789789... = − + 978/999 = − + = =
An even faster method is to ignore the decimal point completely and go like this
1.23444... = = (denominator has one 9 and two 0s because one digit repeats and there are two non-repeating digits after the decimal point)
0.3789789... = = (denominator has three 9s and one 0 because three digits repeat and there is one non-repeating digit after the decimal point)
It follows that any repeating decimal with period n, and k digits after the decimal point that do not belong to the repeating part, can be written as a (not necessarily reduced) fraction whose denominator is (10n − 1)10k.
Conversely the period of the repeating decimal of a fraction will be (at most) the smallest number n such that 10n − 1 is divisible by d.
For example, the fraction has d = 7, and the smallest k that makes 10k − 1 divisible by 7 is k = 6, because 999999 = 7 × 142857. The period of the fraction is therefore 6.
In compressed form
The following picture suggests kind of compression of the above shortcut.
Thereby represents the digits of the integer part of the decimal number (to the left of the decimal point), makes up the string of digits of the preperiod and its length, and being the string of repeated digits (the period) with length which is nonzero.
In the generated fraction, the digit will be repeated times, and the digit will be repeated times.
Note that in the absence of an integer part in the decimal, will be represented by zero, which being to the left of the other digits, will not affect the final result, and may be omitted in the calculation of the generating function.
Examples:
The symbol in the examples above denotes the absence of digits of part in the decimal, and therefore and a corresponding absence in the generated fraction.
Repeating decimals as infinite series
A repeating decimal can also be expressed as an infinite series. That is, a repeating decimal can be regarded as the sum of an infinite number of rational numbers. To take the simplest example,
The above series is a geometric series with the first term as and the common factor . Because the absolute value of the common factor is less than 1, we can say that the geometric series converges and find the exact value in the form of a fraction by using the following formula where a is the first term of the series and r is the common factor.
Similarly,
Multiplication and cyclic permutation
The cyclic behavior of repeating decimals in multiplication also leads to the construction of integers which are cyclically permuted when multiplied by certain numbers. For example, . 102564 is the repetend of and 410256 the repetend of .
Other properties of repetend lengths
Various properties of repetend lengths (periods) are given by Mitchell and Dickson.
The period of for integer k is always ≤ k − 1.
If p is prime, the period of divides evenly into p − 1.
If k is composite, the period of is strictly less than k − 1.
The period of , for c coprime to k, equals the period of .
If k = 2a·5bn where n > 1 and n is not divisible by 2 or 5, then the length of the transient of is max(a, b), and the period equals r, where r is the multiplicative order of 10 mod n, that is the smallest integer such that .
If p, p′, p″,... are distinct primes, then the period of equals the lowest common multiple of the periods of , , ,....
If k and k′ have no common prime factors other than 2 or 5, then the period of equals the least common multiple of the periods of and .
For prime p, if
for some m, but
then for c ≥ 0 we have
If p is a proper prime ending in a 1, that is, if the repetend of is a cyclic number of length p − 1 and p = 10h + 1 for some h, then each digit 0, 1, ..., 9 appears in the repetend exactly h = times.
For some other properties of repetends, see also.
Extension to other bases
Various features of repeating decimals extend to the representation of numbers in all other integer bases, not just base 10:
Every real number can be represented as an integer part followed by a radix point (the generalization of a decimal point to non-decimal systems) followed by a finite or infinite number of digits.
If the base is an integer, a terminating sequence obviously represents a rational number.
A rational number has a terminating sequence if all the prime factors of the denominator of the fully reduced fractional form are also factors of the base. These numbers make up a dense set in and .
If the positional numeral system is a standard one, that is it has base
combined with a consecutive set of digits
with , and , then a terminating sequence is obviously equivalent to the same sequence with non-terminating repeating part consisting of the digit 0. If the base is positive, then there exists an order homomorphism from the lexicographical order of the right-sided infinite strings over the alphabet into some closed interval of the reals, which maps the strings and with and to the same real number – and there are no other duplicate images. In the decimal system, for example, there is 0. = 1. = 1; in the balanced ternary system there is 0. = 1. = .
A rational number has an indefinitely repeating sequence of finite length , if the reduced fraction's denominator contains a prime factor that is not a factor of the base. If is the maximal factor of the reduced denominator which is coprime to the base, is the smallest exponent such that divides . It is the multiplicative order of the residue class which is a divisor of the Carmichael function which in turn is smaller than . The repeating sequence is preceded by a transient of finite length if the reduced fraction also shares a prime factor with the base. A repeating sequence
represents the fraction
An irrational number has a representation of infinite length that is not, from any point, an indefinitely repeating sequence of finite length.
For example, in duodecimal, = 0.6, = 0.4, = 0.3 and = 0.2 all terminate; = 0. repeats with period length 4, in contrast with the equivalent decimal expansion of 0.2; = 0. has period 6 in duodecimal, just as it does in decimal.
If is an integer base and is an integer, then
For example 1/7 in duodecimal:
which is 0.base12. 10base12 is 12base10, 102base12 is 144base10, 21base12 is 25base10, A5base12 is 125base10.
Algorithm for positive bases
For a rational (and base ) there is the following algorithm producing the repetend together with its length:
function b_adic(b,p,q) // b ≥ 2; 0 < p < q
digits = "0123..."; // up to the digit with value b–1
begin
s = ""; // the string of digits
pos = 0; // all places are right to the radix point
while not defined(occurs[p]) do
occurs[p] = pos; // the position of the place with remainder p
bp = b*p;
z = floor(bp/q); // index z of digit within: 0 ≤ z ≤ b-1
p = b*p − z*q; // 0 ≤ p < q
if p = 0 then L = 0;
if not z = 0 then
s = s . substring(digits, z, 1)
end if
return (s);
end if
s = s . substring(digits, z, 1); // append the character of the digit
pos += 1;
end while
L = pos - occurs[p]; // the length of the repetend (being < q)
// mark the digits of the repetend by a vinculum:
for i from occurs[p] to pos-1 do
substring(s, i, 1) = overline(substring(s, i, 1));
end for
return (s);
end function
The first highlighted line calculates the digit .
The subsequent line calculates the new remainder of the division modulo the denominator . As a consequence of the floor function floor we have
thus
and
Because all these remainders are non-negative integers less than , there can be only a finite number of them with the consequence that they must recur in the while loop. Such a recurrence is detected by the associative array occurs. The new digit is formed in the yellow line, where is the only non-constant. The length of the repetend equals the number of the remainders (see also section Every rational number is either a terminating or repeating decimal).
Applications to cryptography
Repeating decimals (also called decimal sequences) have found cryptographic and error-correction coding applications. In these applications repeating decimals to base 2 are generally used which gives rise to binary sequences. The maximum length binary sequence for (when 2 is a primitive root of p) is given by:
These sequences of period p − 1 have an autocorrelation function that has a negative peak of −1 for shift of . The randomness of these sequences has been examined by diehard tests.
See also
Decimal representation
Full reptend prime
Midy's theorem
Parasitic number
Trailing zero
Unique prime
0.999..., a repeating decimal equal to one
Pigeonhole principle
Notes
External links
Elementary arithmetic
Numeral systems
de:Rationale Zahl#Dezimalbruchentwicklung | Repeating decimal | [
"Mathematics"
] | 7,686 | [
"Elementary arithmetic",
"Mathematical objects",
"Elementary mathematics",
"Numeral systems",
"Arithmetic",
"Numbers"
] |
13,612,789 | https://en.wikipedia.org/wiki/N%2CN%27-Diisopropylcarbodiimide | {{DISPLAYTITLE:N,N'''-Diisopropylcarbodiimide}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 424839902
| Name =
| ImageFile = N,N'-methanediylidenebis(propan-2-amine) 200.svg
| ImageSize = 220
| ImageFile1 = N,N'-Diisopropylcarbodiimide molecule ball.png
| ImageSize1 = 240
| ImageAlt1 = Ball-and-stick model of the N,N'-diisopropylcarbodiimide molecule
| PIN = N,N-Di(propan-2-yl)methanediimine
| OtherNames = Diisopropylmethanediimine, DIC
|Section1=
|Section2=
|Section3=
}}N,-Diisopropylcarbodiimide' is a carbodiimide used in peptide synthesis. As a liquid, it is easier to handle than the commonly used N,-dicyclohexylcarbodiimide, a waxy solid. In addition, N,-diisopropylurea, its byproduct in many chemical reactions, is soluble in most organic solvents, a property that facilitates work-up.
SafetyIn vivo'' dermal sensitization studies according to OECD 429 confirmed DIC is a strong skin sensitizer, showing a response at 0.20 wt% in the Local Lymph Node Assay (LLNA) placing it in Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Dermal Sensitization Category 1A. Thermal hazard analysis by differential scanning calorimetry (DSC) shows DIC poses minimal explosion risks.
References
Peptide coupling reagents
Carbodiimides
Reagents for biochemistry
Biochemistry
Biochemistry methods
Isopropylamino compounds | N,N'-Diisopropylcarbodiimide | [
"Chemistry",
"Biology"
] | 426 | [
"Biochemistry methods",
"Carbodiimides",
"Peptide coupling reagents",
"Functional groups",
"Organic compounds",
"nan",
"Reagents for organic chemistry",
"Biochemistry",
"Reagents for biochemistry",
"Organic compound stubs",
"Organic chemistry stubs"
] |
13,615,087 | https://en.wikipedia.org/wiki/IMAP%20IDLE | In email technology, IDLE is an IMAP feature described in RFC 2177 that allows a client to indicate to the server that it is ready to accept real-time notifications.
Significance
The IDLE feature allows IMAP email users to immediately receive any mailbox changes without having to undertake any action such as clicking on a refresh button, or having the email client automatically and repeatedly ask the server for new messages.
Usage
IMAP4 servers that support IDLE will include the string "IDLE" in the result of their CAPABILITY command. This allows email users to receive near instant notification of a new email.
See also
Push-IMAP
Notes
External links
RFC 2177: IMAP4 IDLE
Internet mail protocols | IMAP IDLE | [
"Technology"
] | 141 | [
"Computing stubs",
"Computer science",
"Computer science stubs",
"Computer network stubs"
] |
13,615,347 | https://en.wikipedia.org/wiki/Latent%20semantic%20structure%20indexing | Latent semantic structure indexing (LaSSI) is a technique for calculating chemical similarity derived from latent semantic analysis (LSA).
LaSSI was developed at Merck & Co. and patented in 2007 by Richard Hull, Eugene Fluder, Suresh Singh, Robert Sheridan, Robert Nachbar and Simon Kearsley.
Overview
LaSSI is similar to LSA in that it involves the construction of an occurrence matrix from a corpus of items and the application of singular value decomposition to that matrix to derive latent features. What differs is that the occurrence matrix represents the frequency of two- and three-dimensional chemical descriptors (rather than natural language terms) found within a chemical database of chemical structures. This process derives latent chemical structure concepts that can be used to calculate chemical similarities and structure–activity relationships for drug discovery.
References
Hull, R.D., Fluder, E.M., Singh, S.B., Nachbar, R.B., Sheridan, R.P. and Kearsley, S.K. (2001) "Latent semantic structure indexing (LaSSI) for defining chemical similarity." J Med Chem, 2001 Apr 12;44(8):1177–84.
Hull, R.D., Singh, S.B., Nachbar, R.B., Sheridan, R.P., Kearsley, S.K. and Fluder, E.M. (2001) "Chemical similarity searches using latent semantic structure indexing (LaSSI) and comparison to TOPOSIM." J Med Chem, 2001 Apr 12;44(8):1185–91.
Singh, S.B., Sheridan, R.P., Fluder, E.M. and Hull, R.D. (2001) "Mining the chemical quarry with joint chemical probes: an application of latent semantic structure indexing (LaSSI) and TOPOSIM (Dice) to chemical database mining." J Med Chem, 2001 May 10;44(10):1564–75.
Cheminformatics
Drug discovery | Latent semantic structure indexing | [
"Chemistry",
"Biology"
] | 440 | [
"Life sciences industry",
"Drug discovery",
"Computational chemistry",
"Cheminformatics",
"Medicinal chemistry",
"nan"
] |
13,615,938 | https://en.wikipedia.org/wiki/Dickson%20Prize | The Dickson Prize in Medicine and the Dickson Prize in Science were both established in 1969 by Joseph Z. Dickson and Agnes Fischer Dickson.
Dickson Prize in Medicine
The Dickson Prize in Medicine is awarded annually by the University of Pittsburgh and recognizes US citizens who have made "significant, progressive contributions" to medicine. The award includes $50,000, a bronze medal, and the Dickson Prize Lecture.
Recipients
Source: University of Pittsburgh
1971 Earl W. Sutherland Jr.
1972 Solomon A. Berson and Rosalyn S. Yalow
1973 John H. Gibbon Jr.
1974 Stephen W. Kuffler
1975 Elizabeth F. Neufeld
1976 Frank J. Dixon
1977 Roger Guillemin
1978 Paul Greengard
1979 Bert W. O'Malley
1980 David H. Hubel and Torsten N. Wiesel
1981 Philip Leder
1982 Francis H. Ruddle
1983 Eric R. Kandel
1984 Solomon H. Snyder
1985 Robert C. Gallo
1986 J. Michael Bishop
1987 Elvin A. Kabat
1988 Leroy E. Hood
1989 Bernard Moss
1990 Ernst Knobil
1991 Phillip A. Sharp
1992 Francis Sellers Collins
1993 Stanley B. Prusiner
1994 Bert Vogelstein
1995 Ronald M. Evans
1996 Philippa Marrack
1997 Ed Harlow and Eric Steven Lander
1998 Richard D. Klausner
1999 James E. Darnell Jr.
2000 Elizabeth H. Blackburn (Dickson Prize Lecture, April 13, 2000: "Telomere Capping and Cell Proliferation")
2001 Robert G. Roeder (Dickson Prize Lecture, September 12, 2001: "Regulation of Transcription in Human Cells: Complexities and Challenges")
2002 C. David Allis (Dickson Prize Lecture, September 18, 2002: "Translating the Histone Code: A Tale of Tails")
2003 Susan L. Lindquist (Dickson Prize Lecture, September 24, 2003: "Protein Conformation as a Pathway to Understanding Cellular Processes, Disease and Bio-Inspired Materials")
2004 Elaine Fuchs (Dickson Prize Lecture, 2004: "Skin Stem Cells and Their Lineages")
2005 Ronald W. Davis (Dickson Prize Lecture, 2005: "New Genomic Technology for Yeast Applied to Clinical Medicine")
2006 Roger D. Kornberg (Dickson Prize Lecture, October 5, 2006: "Chromatin and Transcription")
2007 Carol W. Greider (Dickson Prize Lecture, October 11, 2007: "Telomerase and the Consequences of Telomere Dysfunction")
2008 Randy W. Schekman (Dickson Prize Lecture, "Dissecting the Secretion Process: From Basic Mechanism to Human Disease")
2009 Victor Ambros (Dickson Prize Lecture, "MicroRNAs, from Model Organisms to Human Biology.")
2010 Stephen J. Elledge
2011 J. Craig Venter
2012 Brian J. Druker
2013 Huda Y. Zoghbi (Dickson Prize lecture, Thursday, October 3, 2013: "Rett Syndrome and MECP2 Disorders: From the Clinic to Genes and Neurobiology.")
2014 Jeffrey I. Gordon
2015 Karl Deisseroth
2016 Jennifer Doudna
2017 David M. Sabatini
2018 Bonnie Bassler
2019 Ruslan Medzhitov
2020 James J. Collins
2021 Cynthia Kenyon
2022 Carolyn Bertozzi
2023 Clifford Brangwynne
2024 Leslie B. Vosshall
Dickson Prize in Science
The Dickson Prize in Science is awarded annually by Carnegie Mellon University and recognizes those who "have made the most progress in the scientific field in the United States for the year in question." The award is dated by the year in which it was announced, which is often the year before the lecture occurs.
Recipients
Source: Carnegie Mellon University
1970–71 Richard Bellman
1971–72 George Palade and Keith Roberts Porter
1972–73
1973–74 Elias J. Corey
1974–75 David H. Geiger, civil engineering
1975–76 – not awarded
1976–77 – not awarded
1977–78 John H. Sinfelt
1978–79 Seymour Benzer
1979–80 – not awarded
1980–81 John Werner Cahn
1981–82 – not awarded
1982–83 Harden M. McConnell
1983–84 Edward Fredkin
1985–86 Norman Davidson
1986–87 Benjamin Widom
1987–88 Mitchell Feigenbaum
1988–89 Joan A. Steitz
1989–90 Richard E. Dickerson
1990–91 F. Sherwood Rowland
1991–92 David Botstein
1992–93 Paul Lauterbur
1993–94 Vera Rubin
1994–95 Raymond Kurzweil
1995–96 Leland Hartwell
1996–97
1997–98 Walter Alvarez
1998–99 Peter Shor, 25th recipient (Dickson Lecture, November 8, 1999, "Quantum Computing")
1999–2000 Howard Raiffa (Dickson Lecture, Tue. April 4, 2000: "Analytical Roots of a Decision Scientist"
2000–01 Alexander Pines (Dickson Lecture, April 11, 2001: "Some Magnetic Moments"
2001–02 Carver Mead (Dickson Lecture, March 19, 2002: "The Coming Revolution in Photography")
2002–03 Robert Langer (Dickson Lecture, February 26, 2003: "Biomaterials And How They Will Change Our Lives")
2003–04 Marc W. Kirschner (Dickson Lecture, March 30, 2004: "Timing the Inner Cell Cycle")
2004–05 George Whitesides (Dickson Lecture, March 28, 2005: "Assumptions: If common assumptions about the modern world break down, then what could science and technology make happen?")
2005–06 David Haussler (Dickson Lecture, March 9, 2006: "Ultraconserved elements, living fossil transposons, and rapid bursts of change: reconstructing the uneven evolutionary history of the human genome"
2006–07 Jared Diamond (Dickson Lecture, March 26, 2007: "Collapse")
2007–08 Jean Fréchet
2008–09 Richard M. Karp
2009–10 Saul Perlmutter (Dickson Lecture, March 17, 2010: "Stalking Dark Energy & the Mystery of the Accelerating Universe")
2010–11 David A. Tirrell
2011–12 Marvin L. Cohen (March 8, 2012: "Einstein, Condensed Matter Physics, Nanoscience & Superconductivity")
2012–13 François M. M. Morel (March 12, 2013: "Ocean Acidification: Causes, Time Scales & Consequences")
2013–14 Karl Deisseroth (February 3, 2014: "Illuminating the Brain")
2014–15 Joseph M. DeSimone (February 16, 2015: "Breakthroughs in Imprint Lithography and 3D Additive Fabrication")
2015 Judea Pearl (February 29, 2016 : "Science, Counterfactuals and Free Will")
2016 Chad A. Mirkin (February 2, 2017 : "Nanotechnology: Small Things Matter")
2017 Jennifer Doudna (February 1, 2018: "CRISPR Systems: Nature's Toolkit for Genome Editing")
2018 Emery N. Brown (January 31, 2019: "The Dynamics of the Unconscious Brain Under General Anesthesia")
2019 Geraldine Richmond (February 11, 2020: "Surf, Sink or Swim: Understanding Environmentally Important Processes at Water Surfaces")
2020 Lucy Shapiro
2021 Geoffrey Hinton
2022 Richard Aslin
2023 Jennifer Lippincott-Schwartz
2024 Gilda A. Barabino
Further reading
Dickson Prize in Science at Carnegie Mellon University
Dickson Prize in Medicine at University of Pittsburgh
See also
List of medicine awards
Notes
Medicine awards
Awards established in 1969
Carnegie Mellon University | Dickson Prize | [
"Technology"
] | 1,505 | [
"Science and technology awards",
"Medicine awards"
] |
13,616,934 | https://en.wikipedia.org/wiki/Internet%20as%20a%20source%20of%20prior%20art | In the context of patent law, using the Internet as a source of prior art when assessing whether an invention is novel and inventive (two conditions for patentability), may be problematic if it is difficult to ascertain precisely when information on websites became available to the public.
Background
In most patent laws, an (alleged) invention must be new and inventive (or non-obvious, which is basically synonymous of inventive) to be considered patentable, i.e., to be validly patented. An invention is considered new if it does not form part of the prior art (or state of the art), i.e., if it was not already disclosed in the prior art. An invention is considered inventive if it is not obvious in view of the prior art. The prior art is essentially everything available to the public before the filing date of the patent.
In practice, if a device or a method was already known (e.g. described in a scientific paper) before the filing date of the patent covering the device or the method or if the device or method is obvious in view of what was known before the filing date, then, in general, it is not considered new (because known before the filing date) or not considered inventive (because obvious in view of what was known before the filing date of the patent), and then not considered patentable. A patent cannot be obtained for the device or method, or, if obtained (granted), it can generally be "invalidated".
The identification of the prior art is therefore of utmost importance to determine whether an invention is patentable, i.e. whether a patent can be granted for an invention (or whether a patent granted for an invention is valid). The purpose of the novelty criterion is to prevent the prior art being patented again.
The Internet is a popular source of technical information and is of particular interest for the purposes of establishing the prior art. Its use is however surrounded by concerns as to its reliability.
Jurisdictions
European Patent Organisation
In August 2009, the European Patent Office (EPO) published a "notice concerning internet citations" to "[set] out the practice followed at the EPO when citing documents retrieved from the internet in both the European and the PCT procedure." The notice is not binding on the Boards of Appeal. Regarding the standard of proof, the notice reads:
"When an internet document is cited against an application or patent, the same facts are to be established as for any other piece of evidence, including standard paper publications ... This evaluation is made according to the principle of "free evaluation of evidence" ... That means that each piece of evidence is given appropriate weight according to its probative value, which is evaluated in view of the particular circumstances of each case. For assessing these circumstances, the balance of probabilities will be used as the standard of proof, as generally applied by the boards of appeal. According to this standard, it is not sufficient that the alleged fact (e.g. the publication date) is merely probable; the examining division must be convinced that it is correct. It does mean, however, that proof beyond reasonable doubt ("up to the hilt") of the alleged fact is not required."
In 2012, Board of Appeal 3.5.04 issued two decisions, namely T 1553/06 and T 2/09, on the issue of Internet disclosures. The two decisions originate from a contrived test case built by the parties, i.e. the patent proprietor and the opponent. In decision T 1553/06 (page 72), the Board proposed a test to decide whether a document stored on the World Wide Web has been made available to the public, whereas, in decision T2/09, the Board dealt with the alleged public availability of an email transmitted over the Internet.
The EPO Guidelines cite the Internet Archive as well as Wikipedia as possible and credible sources of prior art.
Germany
In 2002, "the Bundespatentgericht in case BPatG 17W (pat) 1/02 (see GRUR 2003 Heft 04, pp 323-325) confirmed in later BPatG 17W (pat) 47/00, ruled that the Internet was not a reliable source for determining the state of the art. This applied also to web archives such as the Internet
Archive."
United States
Internet publications can be relied on as printed publications and thus as prior art under United States patent law. The effective date of the publication will be determined by evidence, such a date of posting listed in the publication itself, or a date of archiving in the Internet Archive.
In August 2006, the United States Patent and Trademark Office (USPTO) ordered examiners to stop using Wikipedia as a source of information for determining the patentability of inventions. However, according to The Patent Librarian's Notebook's blog, examiners continue to cite it, and the number of United States patents issued in 2008 that cited Wikipedia articles nearly doubled to 477, compared to 2007. It increased to 809 citations in 2009.
See also
Public participation in patent examination
Search report
References
Further reading
Bundespatentgericht Beschluss vom 17.10.2002 17 W (pat) 1/02 Verfahren zum Vorabspeichern von Computernetzwerk-Information JurPC Web-Dok. 121/2003
Decision T 1134/06 of the Boards of Appeal of the European Patent Office, January 16, 2007.
Computer law
Patent law | Internet as a source of prior art | [
"Technology"
] | 1,138 | [
"Computer law",
"Computing and society"
] |
13,617,506 | https://en.wikipedia.org/wiki/OAuth | OAuth (short for open authorization) is an open standard for access delegation, commonly used as a way for internet users to grant websites or applications access to their information on other websites but without giving them the passwords. This mechanism is used by companies such as Amazon, Google, Meta Platforms, Microsoft, and Twitter to permit users to share information about their accounts with third-party applications or websites.
Generally, the OAuth protocol provides a way for resource owners to provide a client application with secure delegated access to server resources. It specifies a process for resource owners to authorize third-party access to their server resources without providing credentials. Designed specifically to work with Hypertext Transfer Protocol (HTTP), OAuth essentially allows access tokens to be issued to third-party clients by an authorization server, with the approval of the resource owner. The third party then uses the access token to access the protected resources hosted by the resource server.
History
OAuth began in November 2006 when Blaine Cook was developing an OpenID implementation for Twitter. Meanwhile, Ma.gnolia needed a solution to allow its members with OpenIDs to authorize Mac OS X Dashboard widgets to access their service. Cook, Chris Messina and Larry Halff from Magnolia met with David Recordon to discuss using OpenID with the Twitter and Magnolia APIs to delegate authentication. They concluded that there were no open standards for API access delegation.
The OAuth discussion group was created in April 2007, for a small group of implementers to write the draft proposal for an open protocol. DeWitt Clinton from Google learned of the OAuth project, and expressed his interest in supporting the effort. In July 2007, the team drafted an initial specification. Eran Hammer joined and coordinated the many OAuth contributions creating a more formal specification. On 4 December 2007, the OAuth Core 1.0 final draft was released.
At the 73rd Internet Engineering Task Force (IETF) meeting in Minneapolis in November 2008, an OAuth BoF was held to discuss bringing the protocol into the IETF for further standardization work. The event was well attended and there was wide support for formally chartering an OAuth working group within the IETF.
The OAuth 1.0 protocol was published as RFC 5849, an informational Request for Comments, in April 2010. Since 31 August 2010, all third party Twitter applications have been required to use OAuth.
The OAuth 2.0 framework was published considering additional use cases and extensibility requirements gathered from the wider IETF community. Albeit being built on the OAuth 1.0 deployment experience, OAuth 2.0 is not backwards compatible with OAuth 1.0. OAuth 2.0 was published as RFC 6749 and the Bearer Token Usage specification as RFC 6750, both standards track Requests for Comments, in October 2012.
As of November 2024, the OAuth 2.1 Authorization Framework draft is a work in progress. It consolidates the functionality in RFCs OAuth 2.0, OAuth 2.0 for Native Apps, Proof Key for Code Exchange, OAuth 2.0 for Browser-Based Apps, OAuth Security Best Current, and Bearer Token Usage.
Security issues
OAuth 1.0
On 23 April 2009, a session fixation security flaw in the 1.0 protocol was announced. It affects the OAuth authorization flow (also known as "3-legged OAuth") in OAuth Core 1.0 Section 6.
Version 1.0a of the OAuth Core protocol was issued to address this issue.
OAuth 2.0
In January 2013, the Internet Engineering Task Force published a threat model for OAuth 2.0. Among the threats outlined is one called "Open Redirector"; in early 2014, a variant of this was described under the name "Covert Redirect" by Wang Jing.
OAuth 2.0 has been analyzed using formal web protocol analysis. This analysis revealed that in setups with multiple authorization servers, one of which is behaving maliciously, clients can become confused about the authorization server to use and may forward secrets to the malicious authorization server (AS Mix-Up Attack). This prompted the creation of a new best current practice internet draft that sets out to define a new security standard for OAuth 2.0. Assuming a fix against the AS Mix-Up Attack in place, the security of OAuth 2.0 has been proven under strong attacker models using formal analysis.
One implementation of OAuth 2.0 with numerous security flaws has been exposed.
In April and May 2017, about one million users of Gmail (less than 0.1% of users as of May 2017) were targeted by an OAuth-based phishing attack, receiving an email purporting to be from a colleague, employer or friend wanting to share a document on Google Docs. Those who clicked on the link within the email were directed to sign in and allow a potentially malicious third-party program called "Google Apps" to access their "email account, contacts and online documents". Within "approximately one hour", the phishing attack was stopped by Google, who advised those who had given "Google Apps" access to their email to revoke such access and change their passwords.
In the draft of OAuth 2.1 the use of the PKCE (RFC 7636) extension for native apps has been recommended to all kinds of OAuth clients, including web applications and other confidential clients in order to prevent malicious browser extensions from performing OAuth 2.0 code injection attacks.
Types
OAuth framework specifies several grant types for different use cases. Some of the most common OAuth grant types are:
Authorization Code
PKCE
Client Credentials
Device Code
Refresh Token
Resource Owner Password Credentials (ROPC)
Uses
Facebook's Graph API only supports OAuth 2.0. Google supports OAuth 2.0 as the recommended authorization mechanism for all of its APIs. Microsoft also supports OAuth 2.0 for various APIs and its Azure Active Directory service, which is used to secure many Microsoft and third party APIs.
OAuth can be used as an authorizing mechanism to access secured RSS/Atom feeds. Access to RSS/ATOM feeds that require authentication has always been an issue. For example, an RSS feed from a secured Google Site could not have been accessed using Google Reader. Instead, three-legged OAuth would have been used to authorize that RSS client to access the feed from the Google Site.
Free software client implementations of the OAuth2 protocol such as the LibreOffice OAuth2OOo extension will allow you to access remote resources (ie: via the Google API or the Microsoft Graph API and OAuth 2.0) and possibly even with the LibreOffice Basic language. This makes it very easy to write and use HTTP requests supporting the OAuth 2.0 protocol in LibreOffice macros.
OAuth and other standards
OAuth is a service that is complementary to and distinct from OpenID. OAuth is unrelated to OATH, which is a reference architecture for authentication, not a standard for authorization. However, OAuth is directly related to OpenID Connect (OIDC), since OIDC is an authentication layer built on top of OAuth 2.0. OAuth is also unrelated to XACML, which is an authorization policy standard. OAuth can be used in conjunction with XACML, where OAuth is used for ownership consent and access delegation whereas XACML is used to define the authorization policies (e.g., managers can view documents in their region).
OpenID vis-à-vis pseudo-authentication using OAuth
OAuth is an authorization protocol, rather than an authentication protocol. Using OAuth on its own as an authentication method may be referred to as pseudo-authentication. The following diagrams highlight the differences between using OpenID (specifically designed as an authentication protocol) and OAuth for authorization.
The communication flow in both processes is similar:
(Not pictured) The user requests a resource or site login from the application.
The site sees that the user is not authenticated. It formulates a request for the identity provider, encodes it, and sends it to the user as part of a redirect URL.
The user's browser makes a request to the redirect URL for the identity provider, including the application's request
If necessary, the identity provider authenticates the user (perhaps by asking them for their username and password)
Once the identity provider is satisfied that the user is sufficiently authenticated, it processes the application's request, formulates a response, and sends that back to the user along with a redirect URL back to the application.
The user's browser requests the redirect URL that goes back to the application, including the identity provider's response
The application decodes the identity provider's response, and carries on accordingly.
(OAuth only) The response includes an access token which the application can use to gain direct access to the identity provider's services on the user's behalf.
The crucial difference is that in the OpenID authentication use case, the response from the identity provider is an assertion of identity; while in the OAuth authorization use case, the identity provider is also an API provider, and the response from the identity provider is an access token that may grant the application ongoing access to some of the identity provider's APIs, on the user's behalf. The access token acts as a kind of "valet key" that the application can include with its requests to the identity provider, which prove that it has permission from the user to access those APIs.
Because the identity provider typically (but not always) authenticates the user as part of the process of granting an OAuth access token, it is tempting to view a successful OAuth access token request as an authentication method itself. However, because OAuth was not designed with this use case in mind, making this assumption can lead to major security flaws.
OAuth and XACML
XACML is a policy-based, attribute-based access control authorization framework. It provides:
An access control architecture.
A policy language with which to express a wide range of access control policies including policies that can use consents handled / defined via OAuth.
A request / response scheme to send and receive authorization requests.
XACML and OAuth can be combined to deliver a more comprehensive approach to authorization. OAuth does not provide a policy language with which to define access control policies. XACML can be used for its policy language.
Where OAuth focuses on delegated access (I, the user, grant Twitter access to my Facebook wall), and identity-centric authorization, XACML takes an attribute-based approach which can consider attributes of the user, the action, the resource, and the context (who, what, where, when, how). With XACML it is possible to define policies such as
Managers can view documents in their department
Managers can edit documents they own in draft mode
XACML provides more fine-grained access control than OAuth does. OAuth is limited in granularity to the coarse functionality (the scopes) exposed by the target service. As a result, it often makes sense to combine OAuth and XACML together where OAuth will provide the delegated access use case and consent management and XACML will provide the authorization policies that work on the applications, processes, and data.
Lastly, XACML can work transparently across multiple stacks (APIs, web SSO, ESBs, home-grown apps, databases...). OAuth focuses exclusively on HTTP-based apps.
Controversy
Eran Hammer resigned from his role of lead author for the OAuth 2.0 project, withdrew from the IETF working group, and removed his name from the specification in July 2012. Hammer cited a conflict between web and enterprise cultures as his reason for leaving, noting that IETF is a community that is "all about enterprise use cases" and "not capable of simple". "What is now offered is a blueprint for an authorization protocol", he noted, "that is the enterprise way", providing a "whole new frontier to sell consulting services and integration solutions". In comparing OAuth 2.0 with OAuth 1.0, Hammer points out that it has become "more complex, less interoperable, less useful, more incomplete, and most importantly, less secure". He explains how architectural changes for 2.0 unbound tokens from clients, removed all signatures and cryptography at a protocol level and added expiring tokens (because tokens could not be revoked) while complicating the processing of authorization. Numerous items were left unspecified or unlimited in the specification because "as has been the nature of this working group, no issue is too small to get stuck on or leave open for each implementation to decide."
David Recordon later also removed his name from the specifications for unspecified reasons. Dick Hardt took over the editor role, and the framework was published in October 2012.
David Harris, author of the email client Pegasus Mail, has criticised OAuth 2.0 as "an absolute dog's breakfast", requiring developers to write custom modules specific to each service (Gmail, Microsoft Mail services, etc.), and to register specifically with them.
See also
List of OAuth providers
Data portability
IndieAuth
Mozilla Persona
Security Assertion Markup Language
User-Managed Access
References
External links
Cloud standards
Internet protocols
Internet properties established in 2007
Computer access control
Computer access control protocols | OAuth | [
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11,060,531 | https://en.wikipedia.org/wiki/Electron%20beam%20ion%20trap | Electron beam ion trap (EBIT) is an electromagnetic bottle that produces and confines highly charged ions. An EBIT uses an electron beam focused with a powerful magnetic field to ionize atoms to high charge states by successive electron impact.
It was invented by M. Levine and R. Marrs at LLNL and LBNL.
Operation
The positive ions produced in the region where the atoms intercept the electron beam are tightly confined in their motion by the strong attraction exerted by the negative charge of the electron beam. Therefore, they orbit around the electron beam, crossing it frequently and giving rise to further collisions and ionization. To restrict the ion motion along the direction of the electron beam axis, trapping electrodes carrying positive voltages with respect to a central electrode are used.
The resulting ion trap can hold ions for many seconds and minutes, and conditions for reaching the highest charge states, up to bare uranium (U92+) can be achieved in this way.
The strong charge needed for radial confinement of the ions requires large electron beam currents of tens up to hundreds of milliampere. At the same time, high voltages (up to 200 kilovolts) are used for accelerating the electrons in order to achieve high charge states of the ions.
To avoid charge reduction of ions by collisions with neutral atoms from which they can capture electrons, the vacuum in the apparatus is usually maintained at UHV levels, with typical pressure values of only 10−12 torr, (~10−10 pascal).
Applications
EBITs are used to investigate the fundamental properties of highly charged ions e. g. by photon spectroscopy in particular in the context of relativistic atomic structure theory and quantum electrodynamics (QED). Their suitability to prepare and reproduce in a microscopic volume the conditions of high temperature astrophysical plasmas and magnetic confinement fusion plasmas make them very appropriate research tools. Other fields include the study of their interactions with surfaces and possible applications to microlithography.
References
– First EBIT atomic spectroscopy measurement
External links
Concepts in astrophysics
Atomic physics
Electromagnetism
Electron beam
American inventions
Particle traps | Electron beam ion trap | [
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"Electron beam",
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11,061,937 | https://en.wikipedia.org/wiki/Anna%20Krylov | Anna Igorevna Krylov (Russian: Анна Игоревна Крылова) is the USC Associates Chair in Natural Sciences and Professor of Chemistry at the University of Southern California (USC). Working in the field of theoretical and computational quantum chemistry, she is the inventor of the spin-flip method. Krylov is the president of Q-Chem, Inc. and an elected member of the International Academy of Quantum Molecular Science, the Academia Europaea, and the American Academy of Sciences and Letters.
Life and education
Born in Donetsk, Ukraine (May 6, 1967), Krylov received her M.Sc. (with honors) in Chemistry from Moscow State University in 1990 and her Ph.D. (summa cum laude) from The Hebrew University of Jerusalem working under the supervision of Professor Robert Benny Gerber. Her Ph.D. research at the Fritz Haber Center focused on molecular dynamics in rare gas clusters and matrices.
Career
Upon completing her Ph.D. in 1996, Krylov joined the group of Prof. Martin Head-Gordon at the University of California, Berkeley, as a postdoctoral research associate, where she became involved with electronic structure method development. In 1998, she joined the Department of Chemistry at USC.
Research
Professor Krylov leads the iOpenShell lab, a research group focused on theoretical modeling of open-shell and electronically excited species. She develops robust black-box methods to describe complicated multi-configurational wave functions in single-reference formalisms, such as coupled-cluster and equation-of-motion (or linear response) approaches. She developed the spin-flip approach, which extends coupled-cluster and density functional methods to biradicals, triradicals, and bond-breaking. Krylov has also contributed to the development of molecular orbital concepts in the framework of many-body wave functions and to the extension of molecular orbital theory to the domain of non-linear optical properties and meta-stable electronic states. In addition, Krylov develops many-body theories for describing metastable electronic states (resonances) and tools for spectroscopy modeling, including non-linear optical properties and core-level transitions. Krylov is also known for her development of efficient algorithms and software for quantum chemistry computations. She is one of the developers of the open-source libtensor library for many-body calculations and the Q-Chem electronic structure package.
Using the tools of computational chemistry, and in collaboration with numerous experimental laboratories, Krylov also investigates the role that radicals and electronically excited species play in such diverse areas as combustion, gas- and condensed-phase chemistry, astrochemistry, solar energy, quantum information storage, bioimaging, and light-induced biological processes. She has authored over 300 publications and has delivered more than 300 invited lectures, including the 2012 Löwdin Lecture at Uppsala University Sweden, the 2013 Coulson Lecture at the University of Georgia, the 2018 Davison Lecture at the University of North Texas, and the 2023 Hans Hellmann Lecture at the Philipps-Universität Marburg, Germany.
Science education and outreach
Krylov has developed educational materials (computational labs and tutorials) aiming to increase quantum chemistry literacy among chemists. She has also developed films to help popularize science. The two iOpenShell films, Shine a Light and Laser, have been viewed more than 66,000 times on YouTube since September 2009. In 2015, Krylov delivered a public lecture in the Telluride Science Research Center Town Talk series entitled “Molecules and Light: The Story of Life, Death, and our Quest for Knowledge”.
Awards
Krylov has received worldwide recognition, in particular for her invention of the spin-flip method. She received the 2007 WATOC (World Association of Theoretical and Computational Chemists) Dirac Medal for her "outstanding research on new methods in electronic structure theory for the description of bond-breaking, in particular the spin-flip method", and the Agnes Fay Morgan Research Award, given by Iota Sigma Pi National Honor Society for outstanding research achievements to a woman chemist or biochemist under 40 years of age. She is the recipient of a Friedrich Wilhelm Bessel Research Award from the Alexander von Humboldt Foundation for developing robust electronic structure methods for open-shell and electronically excited species and creative use of ab initio theory to understand the chemistry of biomolecules, reaction intermediates, and photoinduced processes; and the recipient of the 2012 Theoretical Chemistry Award from the Physical Chemistry Division of the American Chemical Society. In addition, she has received the USC Melon Mentoring Award, the Hanna Reisler Mentoring Award from the WiSE program, the USC Phi Kappa Phi Faculty Recognition Award, and the INSIGHT Into Diversity Inspiring Women in STEM Award. In 2017, Krylov was recognized with the Mildred Dresselhaus Award from the Center for Ultrafast Imaging at DESY in Hamburg, Germany. In 2018, she was awarded a Simons Fellowship in Theoretical Physics from the Simons Foundation. In 2019 she received the American Physical Association's prestigious Earle K. Plyler Prize for Molecular Spectroscopy & Dynamics for her:"innovative work developing high accuracy electronic structure theory to inspire interpretation of spectroscopy of radicals, excited states, and ionization resonances in small molecules, biomolecules, and condensed phase solutes."In 2022, she received the USC Associates Award for Creativity in Research and Scholarship, the highest scholarly award granted by the University. That same year, she received the inaugural Communicator of the Year Award, Science and Mathematics, from the USC Dornsife College of Letters, Arts, and Sciences. The award recognized her efforts to inform the scientific community and the general public through writings and speaking engagements of "the growing influence of politics and moral trends within STEM fields." In 2023, Krylov was inducted into the American Academy of Sciences and Letters and awarded the academy's inaugural Barry Prize for Distinguished Intellectual Achievement.
Krylov is a fellow of the American Physical Society, the American Chemical Society, the Royal Society of Chemistry, and the American Association for the Advancement of Science.
Professional merit
Krylov has served on the editorial boards of numerous peer-review journals, including Annual Review of Physical Chemistry, the Journal of Chemical Physics, the Journal of Physical Chemistry, Chemical Physics Letters, the International Journal of Quantum Chemistry, Physical Chemistry–Chemical Physics, Molecular Physics, and Wires Computational Molecular Science. She has served as a guest editor of special issues of J. Phys. Chem. A honoring Prof. Benny Gerber and Prof. Hanna Reisler, the special issue of Chemical Reviews on Theoretical Modeling of Excited-State Processes, and the special issue of Physical Chemistry–Chemical Physics on Quantum Information Science. Currently, she is an associate editor of Physical Chemistry-Chemical Physics (RSC) and of Wires Computational Molecular Science (Wiley).
Krylov has organized numerous symposia and is a board member of WATOC and the International Society for Theoretical Chemical Physics. She is the president of Q-Chem Inc. and a developer of Q-Chem, one of the world's leading ab initio quantum chemistry programs. In addition, she is an elected member of the International Academy of Quantum Molecular Science and an elected member (foreign) of the Academia Europaea.
In addition to her permanent appointment at USC, Krylov has served as a visiting professor at Caltech, University of Minnesota (Minneapolis), University of Colorado (JILA), Heidelberg University, University of Mainz, University of Groningen, the Donostia International Physics Center, and the Center of Ultrafast Imaging at DESY in Hamburg.
Activism
Krylov is active in the promotion of gender equality in STEM fields, especially in theoretical chemistry. She created and maintains the web directory Women in Theoretical and Computational Chemistry, Material Science, and Biochemistry, which currently lists more than 400 scientists holding tenure and tenure track academic positions, or equivalent positions in industry, national laboratories, and other leading research establishments. She has delivered several talks on gender equality in STEM including a lecture at the international symposium in Uppsala, Sweden.
Krylov opposes the distinction between anti-Zionism and anti-Semitism. . She has alleged that students protesting in 2024 against the Israeli war in Gaza made "unhinged screams calling for Intifada and abolishment of the Jewish homeland," told a "barrage of outright lies," and engaged in "slandering" of Jewish faculty member John Strauss. . In response to an open statement written by USC's Department of Gender and Sexuality Studies expressing opposition to Israeli policy toward Palestinians, Krylov signed a letter of USC faculty condemning the statement .
She is a founding member of the Academic Freedom Alliance and a member of its academic leadership committee. Her paper, "The Peril of Politicizing Science," which "launched a national conversation among scientists and the general public" on the growing influence of political ideology over STEM, has received over 100,000 views and, according to Altmetric, was the all-time highest-ranked article in the Journal of Physical Chemistry Letters. Her works have been translated into Polish, Estonian, French, and Russian.
References
External links
The Krylov iOpenShell Research Group Page
Anna Krylov's academic genealogy
University of Southern California faculty
Members of the International Academy of Quantum Molecular Science
Living people
American women chemists
Computational chemists
Theoretical chemists
1967 births
American women academics
21st-century American women
Chemical physicists
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11,062,043 | https://en.wikipedia.org/wiki/Porphyromonas%20gingivalis | Porphyromonas gingivalis belongs to the phylum Bacteroidota and is a nonmotile, Gram-negative, rod-shaped, anaerobic, pathogenic bacterium. It forms black colonies on blood agar.
It is found in the oral cavity, where it is implicated in periodontal disease, as well as in the upper gastrointestinal tract, the respiratory tract, and the colon. It has been isolated from women with bacterial vaginosis.
Collagen degradation observed in chronic periodontal disease results in part from the collagenase enzymes of this species. It has been shown in an in vitro study that P. gingivalis can invade human gingival fibroblasts and can survive in the presence of antibiotics. P. gingivalis invades gingival epithelial cells in high numbers, in which case both bacteria and epithelial cells survive for extended periods of time. High levels of specific antibodies can be detected in patients harboring P. gingivalis.
P. gingivalis infection has been linked to Alzheimer's disease and rheumatoid arthritis. It contains the enzyme peptidyl-arginine deiminase, which is involved in citrullination. Patients with rheumatoid arthritis have increased incidence of periodontal disease; antibodies against the bacterium are significantly more common in these patients.
P. gingivalis is divided into K-serotypes based upon capsular antigenicity of the various types.
Genome
The genome of P. gingivalis was described in 2003 revealing 1,990 open reading frames (i.e. protein-coding sequences), encoded by 2,343,479 bp, with an average G+C content of 48.3%. An estimated 463 genes are essential.
Virulence factors
Gingipain
Arg-gingipain (Rgp) and lys-gingipain (Kgp) are endopeptidase enzymes secreted by P. gingivalis. These gingipains serve many functions for the organism, contributing to its survival and virulence.
Arg-gingipains have been found to play a key role in the collection of nutrients for P. gingivalis survival. Rgp degrades large peptides of the host organism to provide the bacterium with an abundant nitrogen and carbon source from human serum albumin. P. gingivalis can also degrade transferrin within host cells which provides the organism with an abundant iron source needed to perform multiple cellular functions.
The gingipains are also responsible for a number of necessary functions related to host invasion and colonization. Rgp gingipains are necessary for adhesion and invasion as they processed precursor proteins of long fimbriae. The P. gingivalis genes encoding RgpA, Kgp, and hemagglutinin A (HagA) were strongly expressed after incubation with T. denticola. The hemagglutinin adhesion domain-containing proteins act to increase adhesive capacities of P. gingivalis with other bacterial species. They are also associated with coordinating the integrity of the biofilm in the developing and maturation phase. Lys- gingipains (Kgp) can bind to immobilized matrix proteins fibrinogen and fibronectin and may have a role in host colonization.
Gingipains also have the ability to degrade multiple signals of the host immune response. They have the ability to cleave subclass 1 and 3 IgG antibodies as well as proinflammatory cytokines such as IL-1β, IL-2, IL-6, TNF-α and IL-8 in regions of high P. gingivalis concentration, impairing host immune response function. Rgp can inhibit IL-2 accumulation in T-cells, which enables it to evade the host adaptive immune response, by modulating T-cell communication and proliferation.
Gingipains are key factors in tissue damage symptoms of periodontitis, which results from the degradation of matrix metalloproteins, collagen, and fibronectin. Degradation of these substrates interferes with interactions between host cells and the extracellular matrix, therefore impeding wound healing and causing destruction of periodontal tissues. Rgp is responsible for eliciting the host inflammatory response via the p38α MAPK transduction pathway. This response likely contributes to the inflammatory nature of periodontitis and is involved in tissue and bone destruction.
Gingipains have been associated with Alzheimer's disease (AD). Gingipains were discovered from TMAs of patients exhibiting AD brain pathology. Both RgpB and Kgp were discovered from hippocampus and cerebral cortex of AD patients and were found to be associated with tau load, a marker for AD pathology and ubiquitin, which accumulates in tau tangles and amyloid beta plaques in AD brain. P. gingivalis 16S rRNA was also discovered in the cerebral cortex and csf of AD brains. Pretreatment with gingipain inhibitors protected neuron cell degradation caused by administration of gingipains in murine model.
Capsular polysaccharide
The encapsulated strain of P. gingivalis is much more virulent than the nonencapsulated strain in a mouse abscess model. The capsule is a capsular polysaccharide and when present down regulates cytokine production especially proinflammatory cytokines IL-1β, IL-6, IL-8, and TNF-α, indicating host evasion responses. However, other studies have found the capsular polysaccharide to elicit host immune responses like neutrophil migration and dose and time dependent expression of cell migration chemokines like MCP-1, KC, MIP-2 and RANTES in capsular polysaccharide-challenged murine peritoneal macrophages. These conditions are likely to contribute to the inflammatory lesions observed in periodontitis.
Vaccines made from capsular polysaccharide of P. gingivalis apparently impair oral bone loss in murine models. These vaccines have been able to elicit potent immune responses such as increased IgM and IgG responses that recognize whole P. gingivalis organisms.
Fimbriae
Fimbriae are appendages involved in cellular attachment and greatly contribute to virulence and are found on many Gram-negative and some Gram-positive bacteria.
P. gingivalis virulence is heavily associated with fimbriae as they have been characterized to be key factors in adhesion, invasion, and colonization. Fimbriae are also responsible for invasion of membrane vesicles into host cells. They were found to bind to cellular α5β1 integrins, which mediated adherence and impaired the homeostatic controls of host cells. Fimbriae were also found to be associated with modulating β2 integrin adhesive activity for uptake by monocytes using the CD14/TLR2/PI3K signaling complex, which may contribute to intracellular evasion tactics by P. gingivalis. P. gingivalis has long fimbriae, short fimbriae, and accessory components, each of which have distinct functions.
Long fimbriae
Long fimbriae (FimA), also known as major fimbriae, are long, peritrichous, filamentous components. They have a role in initial attachment and organization of biofilms, as they act as adhesins that mediate invasion and colonization of host cells contributing to P. gingivalis virulence.
Short fimbriae
Short fimbriae (Mfa1), also known as minor fimbriae, have distinct roles from long fimbriae and are characterized to be essential for cell-cell auto aggregation and recruitment for microcolony formation. Short fimbriae are involved in cell-cell adhesion with other dental commensals. It was found to and develop biofilm in conjunction with Streptococcus gordonii by interaction with SspB streptococcal surface polypeptide. This interaction may be essential in the invasion of dentinal tubules by P. gingivalis.
Accessory fimbriae
Fim C, D, and E accessory components associate with the main FimA protein and have a role in binding with matrix proteins and interaction with CXC-chemokine receptor 4. Loss of function experiments have confirmed that P. gingivalis mutants deficient for Fim C, D, or E have drastically attenuated virulence.
Evasion of host defenses and immune responses
P. gingivalis has many ways of evading host immune responses which affects its virulence. It does this by using a combination of gingipain proteases, a capsular polysaccharide, induction of host cell proliferation, and the cleavage of chemokines responsible for neutrophil recruitment.
Virulent P. gingivalis further modulates leukocyte recruitment by proteolysis of cytokines and chemokines that are secreted by the host cells. The arg-gingipain and lys-gingipains are responsible for this proteolysis. In a study using a mouse model, P. gingivalis was specifically found to down-regulate IL-8 induction, causing delayed neutrophil recruitment. Prevention of neutrophil recruitment may inhibit the clearance of the bacterium from the site of infection allowing for colonization. P. gingivalis is able to evade opsonophagocytosis from granulocytes by using Gingipain K (Kgp) to cleave IgG 1 and 3. This further modulates immune response by impairing signaling. Other studies have found that P. gingivalis can subvert the complement pathway through C5αR and C3αR, which modulates the killing capacity of leukocytes, allowing for uncontrolled bacterial growth. P. gingivalis was also found to inhibit pro inflammatory and antimicrobial responses in human monocytes and mouse macrophages by fimbrial binding to CXCR4, inducing PKA signaling and inhibiting TLR-2-mediated immune response.
Once in the host cells, P. gingivalis is capable of inhibiting apoptosis by modulating the JAK/Stat pathway that controls mitochondrial apoptotic pathways. A proliferative phenotype may be beneficial to the bacterium as it provides nutrients, impairs host cell signaling, and compromises the integrity of the epithelial cell layer, allowing for invasion and colonization.
Ecology
P. gingivalis plays an important role in the onset of chronic adult periodontitis. Though it is found in low abundance in the oral cavity, it causes a microbial shift of the oral cavity, allowing for uncontrolled growth of the commensal microbial community. This leads to periodontitis through the disruption of the host tissue homeostasis and adaptive immune response. After using laser capture microdissection plus qRT-PCR to detect P. gingivalis in human biopsies, colocalization of P. gingivalis with CD4+ T cells was observed. However, the infection mechanism of T cells by P. gingivalis remains unknown.
P. gingivalis has been associated with increasing the virulence of other commensal bacteria in both in vivo and in vitro experiments. P. gingivalis outer membrane vesicles were found to be necessary for the invasion of epithelial cells of Tannerella forsythia. P. gingivalis short fimbriae were found to be necessary for coculture biofilm formation with Streptococcus gordonii. Interproximal and horizontal alveolar bone loss in mouse models are seen in coinfections involving P. gingivalis and Treponema denticola. The role of P. gingivalis in periodontitis is studied using specific pathogen-free mouse models of periodontal infections. In these models, P. gingivalis inoculation causes significant bone loss, which is a significant characteristic of the disease. In contrast, germ free mice inoculated with a P. gingivalis monoinfection incur no bone loss, indicating that P. gingivalis alone cannot induce periodontitis.
Pathogenesis and Cardiovascular Comorbidities
While P. gingivalis is a part of the typical microbiotic ecosystem of the oral cavity in humans, it can also become pathogenic is provided with sufficient opportunity. When this occurs, the resultant infection is known as gingivitis or periodontitis.
Periodontal disease, which an infection of the gum tissue driven primarily by P. gingivalis, has been theorized to be linked with other systemic diseases, including Alzheimer’s, atherosclerosis and other cardiovascular diseases. Though there exists no scientific consensus on the mechanism by which these disease processes are linked, evidence for the connection between periodontal disease and cardiovascular diseases including atherosclerosis has been found in both statistical study of human populations, and in vivo studies using a mouse model.
It is thought that periodontitis is linked to cardiovascular disease due to inflammation pathways, which the two pathologies have in common. The inflammation pathway of periodontitis is such that as the infection grows, bacteria, including P. gingivalis are targeted by neutrophils and natural killer immune cells. These cells phagocytize the bacteria, while simultaneously cytokine molecules in the area lead to a proinflammatory environment. This proinflammatory environment is also rich in intercellular signaling molecules including tumor necrosis factor-alpha, interleukins (interleukin 1, interleukin 4, interleukin 10), interferons and transforming growth factor beta. These molecules recruit more enzymes and transcription factors, which then in turn recruit more immune cells, forming a positive feedback loop which can make the immune response, and therefore the inflammation become chronic and systemic. Chronic inflammation of gum tissue can lead to a loss of this tissue and of bone tissue as well. The inflammation upregulates production of RANKL, an intercellular signaling molecule that promotes bone tissue dissolution, leading to a gradual loss of bony tissue. P. gingivalis infection is also thought to lead to oxidative stress. Both chronic systemic inflammation and oxidative stress are factors associated with the onset of cardiovascular disease, and are proposed mechanisms by which periodontal disease may, if it indeed is causationally linked to cardiovascular disease, accelerate the disease process of a cardiovascular disease.
While invasive P. gingivalis is associated with various forms of cardiovascular disease, including stroke, coronary artery disease, atrial fibrillation, and heart failure, the best evidence of a direct causational link is between invasive P. gingivalis (periodontal disease) and atherosclerosis. In vivo and in vitro animal models have found that the fimbriae of P. gingivalis promote host cell entry and atherothrombotic lesion formation once the bacteria enter the bloodstream, such as through lesions in the mouth. P. gingivalis has been shown to accelerate the atherosclerosis disease pathway in mice, as well as being found in human atherosclerotic plaque lesions.
See also
List of bacterial vaginosis microbiota
References
External links
Type strain of Porphyromonas gingivalis at BacDive – the Bacterial Diversity Metadatabase
Bacteroidia
Inflammatory diseases of female pelvic organs
Reproductive system
Gynaecology
Sexual health
Bacterial vaginosis
Bacteria described in 1988 | Porphyromonas gingivalis | [
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11,062,213 | https://en.wikipedia.org/wiki/Train%20Your%20Brain | Train Your Brain: 60 Days to a Better Brain is an English-language version of a Japanese book written by Ryuta Kawashima. The original book sold over a million copies in Japan. Dr. Kawashima found that by performing simple mathematical calculations and reading books aloud, one could retain mental clarity and stave off the mental effects of aging. The book is based on this research.
The first half of the book contains simple mathematical calculations intermingled with memory tests and counting tests. The book recommends that one should do a set of maths questions every day and note the time it takes. This is complemented by a memory test, a counting test, and a stroop test (found at the back of the book) which should be undertaken every five days. A set of graphs are provided at the back of the book so that the results of the tests can be logged.
The concepts presented in Train Your Brain would later be used to create the Nintendo DS game Brain Age: Train Your Brain in Minutes a Day!.
Sources
Kawashima, Ryuta, Train Your Brain: 60 Days to a Better Brain (London, 2006)
Brain Age
Medical books
Personal development | Train Your Brain | [
"Biology"
] | 240 | [
"Personal development",
"Behavior",
"Human behavior"
] |
11,063,114 | https://en.wikipedia.org/wiki/Linear%20relation | In linear algebra, a linear relation, or simply relation, between elements of a vector space or a module is a linear equation that has these elements as a solution.
More precisely, if are elements of a (left) module over a ring (the case of a vector space over a field is a special case), a relation between is a sequence of elements of such that
The relations between form a module. One is generally interested in the case where is a generating set of a finitely generated module , in which case the module of the relations is often called a syzygy module of . The syzygy module depends on the choice of a generating set, but it is unique up to the direct sum with a free module. That is, if and are syzygy modules corresponding to two generating sets of the same module, then they are stably isomorphic, which means that there exist two free modules and such that and are isomorphic.
Higher order syzygy modules are defined recursively: a first syzygy module of a module is simply its syzygy module. For , a th syzygy module of is a syzygy module of a -th syzygy module. Hilbert's syzygy theorem states that, if is a polynomial ring in indeterminates over a field, then every th syzygy module is free. The case is the fact that every finite dimensional vector space has a basis, and the case is the fact that is a principal ideal domain and that every submodule of a finitely generated free module is also free.
The construction of higher order syzygy modules is generalized as the definition of free resolutions, which allows restating Hilbert's syzygy theorem as a polynomial ring in indeterminates over a field has global homological dimension .
If and are two elements of the commutative ring , then is a relation that is said trivial. The module of trivial relations of an ideal is the submodule of the first syzygy module of the ideal that is generated by the trivial relations between the elements of a generating set of an ideal. The concept of trivial relations can be generalized to higher order syzygy modules, and this leads to the concept of the Koszul complex of an ideal, which provides information on the non-trivial relations between the generators of an ideal.
Basic definitions
Let be a ring, and be a left -module. A linear relation, or simply a relation between elements of is a sequence of elements of such that
If is a generating set of , the relation is often called a syzygy of . It makes sense to call it a syzygy of without regard to because, although the syzygy module depends on the chosen generating set, most of its properties are independent; see , below.
If the ring is Noetherian, or, at least coherent, and if is finitely generated, then the syzygy module is also finitely generated. A syzygy module of this syzygy module is a second syzygy module of . Continuing this way one can define a th syzygy module for every positive integer .
Hilbert's syzygy theorem asserts that, if is a finitely generated module over a polynomial ring over a field, then any th syzygy module is a free module.
Stable properties
Generally speaking, in the language of K-theory, a property is stable if it becomes true by making a direct sum with a sufficiently large free module. A fundamental property of syzygies modules is that there are "stably independent" of choices of generating sets for involved modules. The following result is the basis of these stable properties.
Proof. As is a generating set, each can be written
This provides a relation between Now, if is any relation, then
is a relation between the only. In other words, every relation between is a sum of a relation between and a linear combination of the s. It is straightforward to prove that this decomposition is unique, and this proves the result.
This proves that the first syzygy module is "stably unique". More precisely, given two generating sets and of a module , if and are the corresponding modules of relations, then there exist two free modules and such that and are isomorphic. For proving this, it suffices to apply twice the preceding proposition for getting two decompositions of the module of the relations between the union of the two generating sets.
For obtaining a similar result for higher syzygy modules, it remains to prove that, if is any module, and is a free module, then and have isomorphic syzygy modules. It suffices to consider a generating set of that consists of a generating set of and a basis of . For every relation between the elements of this generating set, the coefficients of the basis elements of are all zero, and the syzygies of are exactly the syzygies of extended with zero coefficients. This completes the proof to the following theorem.
Relationship with free resolutions
Given a generating set of an -module, one can consider a free module of of basis where are new indeterminates. This defines an exact sequence
where the left arrow is the linear map that maps each to the corresponding The kernel of this left arrow is a first syzygy module of .
One can repeat this construction with this kernel in place of . Repeating again and again this construction, one gets a long exact sequence
where all are free modules. By definition, such a long exact sequence is a free resolution of .
For every , the kernel of the arrow starting from is a th syzygy module of . It follows that the study of free resolutions is the same as the study of syzygy modules.
A free resolution is finite of length if is free. In this case, one can take and (the zero module) for every .
This allows restating Hilbert's syzygy theorem: If is a polynomial ring in indeterminates over a field , then every free resolution is finite of length at most .
The global dimension of a commutative Noetherian ring is either infinite, or the minimal such that every free resolution is finite of length at most . A commutative Noetherian ring is regular if its global dimension is finite. In this case, the global dimension equals its Krull dimension. So, Hilbert's syzygy theorem may be restated in a very short sentence that hides much mathematics: A polynomial ring over a field is a regular ring.
Trivial relations
In a commutative ring , one has always . This implies trivially that is a linear relation between and . Therefore, given a generating set of an ideal , one calls trivial relation or trivial syzygy every element of the submodule the syzygy module that is generated by these trivial relations between two generating elements. More precisely, the module of trivial syzygies is generated by the relations
such that and otherwise.
History
The word syzygy came into mathematics with the work of Arthur Cayley. In that paper, Cayley used it in the theory of resultants and discriminants.
As the word syzygy was used in astronomy to denote a linear relation between planets, Cayley used it to denote linear relations between minors of a matrix, such as, in the case of a 2×3 matrix:
Then, the word syzygy was popularized (among mathematicians) by David Hilbert in his 1890 article, which contains three fundamental theorems on polynomials, Hilbert's syzygy theorem, Hilbert's basis theorem and Hilbert's Nullstellensatz.
In his article, Cayley makes use, in a special case, of what was later called the Koszul complex, after a similar construction in differential geometry by the mathematician Jean-Louis Koszul.
Notes
References
David Eisenbud, The Geometry of Syzygies, Graduate Texts in Mathematics, vol. 229, Springer, 2005.
Commutative algebra
Homological algebra
Linear algebra
Polynomials | Linear relation | [
"Mathematics"
] | 1,633 | [
"Mathematical structures",
"Polynomials",
"Fields of abstract algebra",
"Category theory",
"Linear algebra",
"Commutative algebra",
"Algebra",
"Homological algebra"
] |
11,063,223 | https://en.wikipedia.org/wiki/Acrocalymma%20medicaginis | Acrocalymma medicaginis is a plant pathogen that causes root and crown rot in alfalfa. It is found in Australia.
References
Lophiostomataceae
Fungal plant pathogens and diseases
Eudicot diseases
Fungi described in 1987
Fungi of Australia
Fungi native to Australia
Fungus species | Acrocalymma medicaginis | [
"Biology"
] | 62 | [
"Fungi",
"Fungus species"
] |
11,063,292 | https://en.wikipedia.org/wiki/Armillaria%20tabescens | Armillaria tabescens (also known as ringless honey mushroom) is a species of fungus in the family Physalacriaceae. It is a plant pathogen. The mycelium of the fungus is bioluminescent.
Hosts and symptoms
Armillaria species infect a wide variety of woody plants. In a survey of 250 permanent plots of trees in Albania, Armillaria tabescens affected multiple species of trees including fir species, where it invaded when the plant was stressed. A study in Greece reported Armillaria tabescens to be more prevalent in areas where the trees were stressed due to limited moisture. In oak trees, it was slightly more damaging and could kill young trees. Armillaria tabescens was also recorded in poplar and eucalyptus plantations, and almond trees were found to be very susceptible to infection. The results of the study by Lushaj et al. showed that Armillaria tabescens was most frequently recorded on fruit and ornamental trees compared to the other species.
Armillaria tabescens causes separation of the bark from the wood by the production of mycelial fans in the trunk, a common sign of Armillaria root rot. It also causes gummosis, patches of gummy material on the surface of plants, which occurs in response to an external stimulus which causes the plant to ooze sap. Other common symptoms are soft rot of cortex, dwarfing, dieback, wilting, and abnormal coloring of the leaves. Small trees are killed rapidly by Armillaria tabescens and the symptoms aren't noticeable until the leaves wilt. However, on larger trees symptoms occur earlier and start as a thin crown with small leaves. A crown of a tree refers to any branches or foliage that are growing out from the trunk. Therefore, thinning of the crown would mean reduced branches and leaves. The trees eventually start yellowing and defoliating followed by fast wilting and dying of limbs. The fungus is a white rot so it breaks down lignin in the wood. The breaking down of the lignin leads to the trees becoming hollow.
Environment
Armillaria tabescens is found in warm and dry regions, so, in Europe, it tends to be in southern areas. It has also been found in altitudes ranging from sea level to . Studies in Europe have found that it exists in south-east England, France, Hungary, Italy, Portugal, Greece and, rarely, Germany and Switzerland. In Japan, it is very rare; only one isolate of Armillaria tabescens was found out of 59 sites surveyed.
Armillaria tabescens grows quickly at and more slowly at . If the soil is moist, fruiting bodies are abundant. It is the first to fruit in September, compared to Armillaria mellea and Armillaria gallica. The fruiting bodies can be seen even earlier if the season has been exceptionally wet. Armillaria tabescens grows poorly on sand and produces shorter rhizomorphs. Rhizomorphs are threadlike structures in fungi that are made up of hyphae. Hyphae are branching structures that release enzymes to absorb nutrients from the host.
Pathogenesis
Armillaria tabescens is a heterothallic species of Armillaria. Heterothallic species perform anastomosis when haploid monokaryon come in contact with one another. Anastomosis is the connection or opening between two things, in this case the mycelium. Mycelium is the vegetative part of the fungus that consists of hyphae. If the two monokaryons are sexually compatible they form a clamp connection. This results in a mycelium consisting of dikaryotic cells. The dikaryon cells predominate in the vegetative phase. In the basidia karyogamy occurs before meiosis and then the formation of basidiospores. The basidiospores then infect the host plant.
Armillaria tabescens is found to attack trees that are already stressed or have a wound. The pathogen can spread its mycelia and get into the trunk or root of a tree. The fungus has the ability to spread its mycelia throughout the root and trunk system and form mycelial mats. Mycelia is damaging to trees because they absorb the nutrients by secreting enzymes to breakdown the plant material. It specifically breaks down lignin because it is a white rot.
No rhizomorphs have been found for Armillaria tabescens in nature. However, Rishbeth and Kile did find rhizomorphs buried in the soil on inocula. Since the species doesn't produce rhizomorphs commonly in the nature, infected roots must come into contact with other potential hosts for infection to occur. So, root grafting provides an effective pathway for the spread of this pathogen. Tsopelas conducted an experiment of inoculating almond trees with Armillaria tabescens and two other Armillaria species. The result of the experiment was that basidiocarps developed 6–8 weeks after the inoculation. The basidiocarps are recognized by not having an annulus around the stalk of the basidium. The basidiospores infect the trees. After two years, it only killed 3 out of the 16 trees and two other trees had symptoms of dieback.
Edibility
The species can be cooked and eaten, even being regarded as choice, but has been reported to cause upset stomachs. Armillaria tabescens additionally contains small levels of antioxidants which have been studied for possible use as protection against lipid peroxidation and free radical damage.
See also
List of bioluminescent fungi
References
Fungal plant pathogens and diseases
tabescens
Bioluminescent fungi
Fungi described in 1772
Fungi of Europe
Fungus species | Armillaria tabescens | [
"Biology"
] | 1,214 | [
"Fungi",
"Fungus species"
] |
11,063,314 | https://en.wikipedia.org/wiki/Biscogniauxia%20marginata | Biscogniauxia marginata is a species of fungus in the family Graphostromataceae. A plant pathogen, it was given its current name by Czech mycologist Zdeněk Pouzar in 1979.
References
Fungi described in 1979
Fungal plant pathogens and diseases
Xylariales
Taxa named by Elias Magnus Fries
Fungus species | Biscogniauxia marginata | [
"Biology"
] | 70 | [
"Fungi",
"Fungus species"
] |
11,063,337 | https://en.wikipedia.org/wiki/Botryosphaeria%20dothidea | Botryosphaeria dothidea is a plant pathogen that causes the formation of cankers on a wide variety of tree and shrub species. It has been reported on several hundred plant hosts and on all continents except Antarctica. B. dothidea was redefined in 2004, and some reports of its host range from prior to that time likely include species that have since been placed in another genus. Even so, B. dothidea has since been identified on a number of woody plants—including grape, mango, olive, eucalyptus, maple, and oak, among others—and is still expected to have a broad geographical distribution. While it is best known as a pathogen, the species has also been identified as an endophyte, existing in association with plant tissues on which disease symptoms were not observed. It can colonize some fruits, in addition to woody tissues.
Life as a plant pathogen – "Bot rot" of apple
White rot, or "Bot rot", of apple is one of the many plant diseases that have been attributed to B. dothidea. Recent analysis has confirmed the presence of B. dothidea, along with other Botryosphaeria species, on Malus sp.. Cankers and other dead wood and bark tissue, as well as mummified fruit (fruit infected by the pathogen and remaining in the orchard) serve as sources of primary and secondary inoculum.
Both pycnidia and pseudothecia are observed on plant tissues, producing conidia and ascospores. Conidia are produced in greater numbers. Using spore traps for airborne spores and funnel traps for rainwater, Sutton (1981) determined that, while both conidia and ascospores of B. dothidea are released from infected pruning waste (dead wood) during rainfall events and conidia are predominantly water-dispersed, ascospores spread in both air and water. Conidia and ascospores germinate most readily at . (B. dothidea has been reported to grow best, in culture, at .) Lenticels and wounds provide locations for wood infection
The cankers of white rot appear similar to those of black rot, caused by Diplodia seriata (formerly B. obtusa). Girdling of limbs by cankers can result in yellowing ("chlorosis") of leaves on affected branches in the spring. While the precise time of fruit infection is unclear, symptoms of fruit rot appear approximately four to six weeks before harvest. The name "white rot" comes from the light brown color of the surface of affected red-skinned apples.
Classification and characteristics
Botryosphaeria dothidea is the type species of the genus Botryosphaeria. While the International Botanical Congress recently emended the International Code of Nomenclature for algae, fungi, and plants to state that one fungal species should be called by one name, the sexual (teleomorphic) and asexual (anamorphic) stages of single fungal species have often been called by different names. B. dothidea was the name given to the teleomorphic form, and Fusicoccum aesculi has been identified the anamorph of B. dothidea, as currently defined. Phillips et al. (2013) chose to use the genus name Botryosphaeria, rather than Fusicoccum, since Botryosphaeria is commonly used and is the type genus of the family Botryosphaeriaceae.
Fries first published a description of B. dothidea as Sphaeria dothidea in Systema Mycologicum in 1823. Cesati and De Notaris described the genus Botryosphaeria and moved the species formerly known as S. dothidea into the new genus.
After determining that a type specimen consistent with the original description of Sphaeria dothidea, on ash, did not exist, Slippers et al. (2004) designated an epitype specimen to go along with a non-sporulating neotype from the collection of Fries, who published the original description of the species. Slippers et al. (2004) then revised the description of B. dothidea. The name is believed to have previously encompassed a species complex, and references to it in older literature might represent species now otherwise identified.
Like other members of the Dothideomycetes, the sexual stage of B. dothidea has bitunicate asci, which are borne in cavities ("ascomata") formed through a process known as "ascolocular development". In the case of B. dothidea, these ascomata are pseudothecia. The asci in the pseudothecia produce ascospores that can then infect plants. Like other species in the order Botryosphaeriales, B. dothidea ascomata have "multilayered dark brown walls" and contain septate pseudoparaphyses which are transparent or translucent (hyaline). Pseudothecia are sometimes located alone and other times clustered together.
In the asexual stage, conidia, which can also infect plants, are produced in pycnidia. The pycnidia and pseudothecia of B. dothidea look very similar. Microconidia have also been reported in at least one B. dothidea isolate. Microconidia are small, asexual spores that often act as male gametes or gametangia (spermatia) in a process of cytoplasmic fusion (plasmogamy)
According to a key provided in Phillips et al. (2013), B. dothidea can be distinguished from six other members of the genus by conidia that are typically longer than 20 μm, have a length to width ratio greater than 4.5, and occur on hosts other than Vaccinium species. These conidia are "narrowly...or irregularly fusiform," have thin walls, and are generally transparent or translucent (hyaline) and aseptate but sometimes form up to two septa and/or darken when they are older. Differentiating between species based on morphology depends on observing multiple samples, to get an idea of prevailing character states, and doing so at the appropriate developmental stage. Sequencing is considered an important companion to morphological identification
References
External links
Index Fungorum
MycoBank
USDA ARS Fungal Databases
Fungal plant pathogens and diseases
Grapevine trunk diseases
Fungi described in 1823
dothidea
Fungus species | Botryosphaeria dothidea | [
"Biology"
] | 1,344 | [
"Fungi",
"Fungus species"
] |
11,063,344 | https://en.wikipedia.org/wiki/Botryosphaeria%20obtusa | Botryosphaeria obtusa is a plant pathogen that causes frogeye leaf spot, black rot and cankers on many plant species. On the leaf it is referred to as frogeye leaf spot; this phase typically affects tree and shrubs. In fruit such as the apple, cranberry and quince, it is referred to as black rot, and in twigs and trunks it causes cankers.
Symptoms
Black rot
Botryosphaeria obtusa enters the fruit through wounds. These can be made by insects, birds or growth cracks. At first a brown spot, near the calyx, appears on the fruit. The spot on the fruit then enlarges and black/brown rings appear on the fruit. The fruit holds its shape, however, unlike other fruit diseases. The fruit will then wither up and can remain on the tree for another year before falling off. During this time pycnidia appear on the surface of the rotted fruit.
Frogeye leaf spot
In leaves the fungus begins by causing purple specks on infected leaves. These then enlarge to cause large spots on the leaf, developing a brown color. The spots appear to have rings of brown with a purple margin, thus giving it its frogeye appearance. The spots can then produce pycnidia which can separate this species of fungus from other possible leaf fungi.
Canker
On twigs, branches and trunks B. obtusa can infect where there has been a winter injury or fire blight cankers. Slightly sunken reddish/brown spots appear on the infected areas of bark. These then enlarge to form cankers, which can then enlarge slightly more each year. The bark usually dies and can, after time, be pulled away from the tree. In older cankers the pycnidia appear on the bark.
Black dead arm disease of grapevine
Botryosphaeria obtusa is the pathogen of black dead arm disease of grapevine. It has been shown to be able to oxidise wood δ-resveratrol into delta-viniferin.
Treatment and control
The most effective treatment is to prune out the infected areas on trees, to ensure transfer between trees does not occur. Fruit that is infected can stay on the tree for over a year, and therefore remaining fruit should be removed to avoid another source of inoculation for other trees. The trimmed branches or dead fruit should then be burned or disposed of immediately as the organism can survive on the dead tissue for a long period of time. Infection of leaves and fruit can be avoided by spraying them with a fungicide. The treatment for the fungicide should be also kept up to date via the manufacturer's instructions.
References
External links
USDA ARS Fungal Database
West Virginia University - Black Rot
Invasive.org - Image Gallery
obtusa
Fungi described in 1832
Fungal plant pathogens and diseases
Apple tree diseases
Grapevine trunk diseases
Eudicot diseases
Taxa named by Lewis David de Schweinitz
Fungus species | Botryosphaeria obtusa | [
"Biology"
] | 610 | [
"Fungi",
"Fungus species"
] |
11,063,364 | https://en.wikipedia.org/wiki/Ceratocystis%20fimbriata | Ceratocystis fimbriata is a fungus and a plant pathogen, attacking such diverse plants as the sweet potato (black rot) and the tapping panels of the Para rubber tree (moldy rot). It is a diverse species that attacks a wide variety of annual and perennial plants. There are several host-specialized strains, some of which, such as Ceratocystis platani that attacks plane trees, are now described as distinct species.
Taxonomy
Ceratocystis fimbriata, the type species of the genus Ceratocystis, was originally described on the sweet potato (Ipomoea batatus) in 1890. It has since been found on a wide variety of annual and perennial plants. It is a large, diverse complex of species that cause wilt-type diseases of many economically important plants. There are thought to be three broad geographic clades, the North American, the Latin American and the Asian clades.
It is thought likely that Ceratocystis fimbriata contains many undescribed, hidden species. One form of the fungus that causes a wilt disease in cacao was in 2005 described as a new species Ceratocystis cacaofunesta. Another form that causes a disease on plane trees (Platanus), and which was previously known as Ceratocystis fimbriata f. platani, was in 2005 elevated to species Ceratocystis platani.
Host and symptoms
Ceratocystis fimbriata is an ascomycete fungal pathogen. The species as a whole can infect a wide variety of hosts, but particular strains are host-specific. One example is the Ipomoea form of the fungus, which is specific to sweet potato (Ipomea batatas) and wild morning glory. Symptoms can be found on the fleshy root or visible in plants. On sweet potato, Ceratocystis fimbriata causes a disease called 'black rot,' which displays firm and dry circular brown/black rots. Infected plants often show stunted growth, wilting, and yellowing. Wilting occurs because this pathogen can also travel through xylem and infect vascular system. During disease, white, fuzzy mycelia with long black perithecia grow out from the lesions. Additionally, research demonstrates that sweet potatoes infected with C. fimbriata demonstrate increased respiration which is partially due to the infection's influence on protein metabolism. Higher respiration rates cause dry weight loss in the tubers which poses a problem for marketability.
Diseases
Black rot of sweet potato
The Ipomoea form of the fungus that attacks the sweet potato (Ipomoea batatas), is thought likely to be native to Latin America, as is the sweet potato itself. It has spread to many locations probably on storage roots. The fungus may appear as a dry, black rot, usually with perithecia and ascospores. In some countries (such as China and Japan) it is an important constraint to sweet potato production. In other areas (such as southeastern USA) the damage is less severe due to the use of resistant varieties and sanitary measures. Fungicides can be used in sweet potato fields or as post-harvest dips of sweet potato roots.
Disease cycle
Ceratocystis fimbriata produces ascospores, and these spores are found at the top of fruiting bodies known as perithecia. There are also chlamydospores, which aid in survival as they overwinter in the soil and on roots.
Chlamydospores survive on infected roots/slips or in the soil and develop on the next season's plant material during spring. Then, mycelium produce long, black perithecia (fruiting structures) that have a sticky mass of ascospores at the top. These ascospores enter and infect new plants through wounds on any part of the plant/tuber/etc and are commonly dispersed by insects, wind, and equipment. After infecting tubers, the disease can be spread up the xylem tissue of the stem causing wilt. Ultimately, this pathogen will continue its lifecycle through vegetative propagation (transplants) of diseased tissue or chlamydospores that overwinter in roots or soil to spread the disease into the next season.
Environment
Environmental conditions such as temperature and nutrient levels are important for C. fimbriata's success. Specifically, temperatures ranging from 23-27 degrees Celsius encourage sporulation and disease growth. Also, pre-sprouting roots at warm temperature favors disease and should be avoided when growing sweet potatoes. This is because roots infected with black rot produce sprouts that frequently rot at the attachment point of the root or the roots develop lesions on the stem that rot below ground. Boron deficiencies in the soil can also enhance the disease. Since many sweet potatoes are grown from roots or slips, any diseased tissue present can lead to more widespread infection.
Management
In order to prevent black rot, it's absolutely essential to avoid using infected seed roots as this is a major way of disease transmission. Host resistance has been found and used successfully against C. fimbriata on sweet potatoes. It is also recommended to perform crop rotation every 2–3 years. Importantly, fungicides only work on seeds and sweet potato slips so if C. fimbriata is already established, fungicides will not control or eliminate disease. Thiabendazole and difenoconazole are effective on C. fimbriata. Finally, good management practices include cleaning all equipment to prevent disease spread. Tubers should be washed and dried before storage and this storage should be in ventilated boxes/crates to eliminate environmental conditions conducive to fungal growth.
Mouldy rot of rubber
On rubber trees (Hevea brasiliensis), C. fimbriata attacks the tapping panel, causing a pale-grey mould on the surface of the panel and dark discoloration in the wood under the surface. Fungicides can be used to treat tapping panels of Hevea.
Wilt and canker of coffee
A fungus attacking Coffea in Indonesia was described as Rostrella coffea in 1900 and this species was synonymized with Ceratocystis fimbriata in 1951. It is widespread in Central America and northern South America, and is a particularly damaging disease in Colombia.
Mango wilt
Mango wilt is known only in Brazil, even though mango trees (Mangifera indica) are grown in other areas where C. fimbriata is common on other plants. Infection typically occurs through fresh wounds on trees although root infections also occur. Infection is often accompanied by secondary attack by various ambrosia beetles.
Ficus wilt
Ficus wilt is a severe disease found in fig trees (Ficus carica) in Brazil. There is also an Asian form of Ficus wilt caused by C. fimbriata found in southern Japan.
Rapid 'Ohi'a death
A fungus initially identified as a form of Ceratocystis fimbriata was identified in 2015 as the cause of widespread mortality in 'ohi'a trees (Metrosideros polymorpha) in the Puna District on the island of Hawai'i. The source of the outbreak is currently unknown. In April 2018, researchers published descriptions of two species of Ceratocystis new to science that are believed to be responsible for rapid 'ohi'a death: C. huliohia and C. lukuohia. The specific names are derived from the Hawai'ian language, meaning "changes the natural state of 'ohi'a" and "destroyer of 'ohi'a", respectively. In May 2018, it was reported that infected 'ohi'a trees have been found on the Hawai'ian island of Kauai. The public has been asked to avoid transportation of 'ohi'a trees or products to slow the spread of the disease.
In other plants
Many other plants are harmed by C. fimbriata. It has caused serious mortality in Eucalyptus plantations in Brazil as well as in the Congo and Uganda. Almonds (Prunus dulcis) in California have been affected by the disease. It has also caused losses in pomegranates (Punica granatum) in India. It causes a dark, dry rot in Taro tubers.
References
External links
Fungi described in 1890
Fungal plant pathogens and diseases
Fungal tree pathogens and diseases
Eudicot diseases
Microascales
Fungus species | Ceratocystis fimbriata | [
"Biology"
] | 1,793 | [
"Fungi",
"Fungus species"
] |
11,063,369 | https://en.wikipedia.org/wiki/Cercospora%20medicaginis | Cercospora medicaginis is a fungal plant pathogen. It is a slow-growing pathogen found on Medicago species, which are widespread Tunisia.
References
medicaginis
Fungal plant pathogens and diseases
Taxa named by Benjamin Matlack Everhart
Fungi described in 1891
Fungus species | Cercospora medicaginis | [
"Biology"
] | 61 | [
"Fungi",
"Fungus species"
] |
11,063,377 | https://en.wikipedia.org/wiki/Thielaviopsis%20basicola | Thielaviopsis basicola is the plant-pathogen fungus responsible for black root rot disease. This particular disease has a large host range, affecting woody ornamentals, herbaceous ornamentals, agronomic crops, and even vegetable crops. Examples of susceptible hosts include petunia, pansy, poinsettia, tobacco, cotton, carrot, lettuce, tomato, and others. Symptoms of this disease resemble nutrient deficiency but are truly a result of the decaying root systems of plants. Common symptoms include chlorotic lower foliage, yellowing of plant, stunting or wilting, and black lesions along the roots. The lesions along the roots may appear red at first, getting darker and turning black as the disease progresses. Black root lesions that begin in the middle of a root can also spread further along the roots in either direction. Due to the nature of the pathogen, the disease can easily be identified by the black lesions along the roots, especially when compared to healthy roots. The black lesions that appear along the roots are a result of the formation of chlamydospores, resting spores of the fungus that contribute to its pathogenicity. The chlamydospores are a dark brown-black color and cause the "discoloration" of the roots when they are produced in large amounts.
Environment
As a poor saprophyte and obligate parasite, T. basicola is often dependent upon favorable environmental conditions. Although the pathogen is able to grow in a variety of soil moistures, wet soil is optimal for greater infection since spores are able to move easily in water. Water plays a role in dispersal of spores and can lead to an increased infection rate. Soil temperatures also play an important role, as temperatures between 55 and 65 °F are favorable for the pathogen. However, temperatures that are higher than 86 °F are unfavorable for the fungus and only traces of the pathogen can be found. At lower temperatures, the severity of the disease increases since the temperatures become unfavorable for and induces stress on the hosts. Alkaline clay soils have proven to be conducive to pathogenicity and also favor the pathogen. This can be attributed to the fact that the pathogen is suppressed at soils with pH less than 5.2, so increasing pH is favorable for severity of disease. There are also cultural conditions which may induce stress on the host plants that favor the pathogen including high soluble salts, excessive nitrogen fertilizer, low organic matter, etc. When the plant undergoes stress due to cultural conditions, there is an increase in susceptibility to opportunistic pathogens such as T. basicola. For this reason, it is important to practice proper cultural conditions such as maintaining proper temperatures, amount of nitrogen fertilizer, and pH of the soil to reduce stress of host plants and decrease susceptibility to disease.
Pathogenesis
Thielaviopsis basicola is a soilborne fungus that belongs to the Ascomycota division of the "true fungi" and is a hemibiotrophic parasite. Fungi belonging to Ascomycota are known to produce asexual and sexual spores, however, a sexual stage has yet to be observed and validated in the Thielaviopsis basicola life cycle, which classifies this species as one of the Deuteromycete or an imperfect fungus. During the asexual reproductive cycle of Thielaviopsis basicola, two types of asexual spores are borne from the hyphae including endoconidia and chlamydospores. Endoconidia are a distinctive type of conidium in that they develop within a hollow cavity inside a hyphal tube and are ejected from the end of this tube to disperse. Both of the aforementioned spores must first undergo physical dissemination in order to begin locating an infection court on a new, viable host. Aside from the normal translocation of spores within the soil environment, vectors such as shore flies have been observed carrying and aerially transmitting Thielaviopsis basicola spores, a phenomenon uncharacteristic of soilborne fungal pathogens. Upon landing on an infected plant, the shore flies feed on the infected tissue and ingest spores along with the plant material, only to excrete the hitchhiking spores in their frass, which ultimately lands on healthy plant tissue continuing the disease cycle. However, it is important to note that this association between vector and soilborne fungi has only been observed in commercial agricultural settings in which artificially controlled environments (i.e. greenhouses) promote conditions that deviate from the natural world.
Following dispersal (via vector-insect, cultural practice, or other translocation means within the soil matrix), the spores will detect an infection site on the host plant (usually root hairs) and germinate in response to the stimuli produced by the root exudates, some of which include sugars, lecithins, and unsaturated triglycerides. Germ tubes emerge from the spores and directly penetrate into the cells of the root hairs (typically the single-cell epidermal layer) via penetration hyphae. The living host plant will typically respond with the development of cell appositions called papillae, which attempt to block the pathogen from penetrating the cell wall and subsequently parasitizing the host's cells. However, most of these early defense mechanisms prove unsuccessful, hence the significance and prevalence of the disease around the world. Advancing, the vegetative hyphal cells differentiate into feeding structures that resemble haustoria, which absorb nutrients biotrophically from the host cells. Once the pathogen has breached the cell wall of the epidermal root cell, it proceeds to release effector compounds that disrupt the host's systemic defense mechanisms. Systemic acquired resistance (SAR) is employed by the host to actively address localized infection and initiate defense signaling cascades throughout the plant. For example, the SAR NPR1 (AtNPR1) gene is of special importance and acts to suppress the infection faculties of Thielaviopsis basicola, effectively imparting resistance to some host plants. Furthermore, research suggests that the NPR1 gene, when over-expressed in transgenic plants, aids in the expression of other defense-related genes such as PR1, effectively improving resistance to infection by Thielaviopsis basicola. NPR1 and its associated benefits for enhancing disease resistance have been recognized as possible tools to use when equipping economically indispensable crops with transgenic resistance to disease.
Once penetration and the establishment of biotrophic feeding structures are successful, the pathogen progresses into the root tissue leaving distinctive black/brown lesions in its wake (lesion coloration can be attributed to thick-walled chlamydospore clusters); it continues proliferating until eventually entering its necrotrophic stage. Hemibiotrophs, like Thielaviopsis basicola, transition from a biotrophic stage to a necrotrophic stage by way of a coordinated effort between different pathogenesis genes that secrete effector proteins capable of manipulating their host's defense system. Research suggests that during biotrophy, certain types of effectors from the pathogen are expressed over others and vice versa during the necrotrophic stage. Once the biotrophic stage is no longer preferred by the pathogen, it will initiate this complicated genetic transition and commence the necrotrophic stage. In order to digest and metabolize nutritive compounds from a necrotic host plant, Thielaviopsis basicola secretes enzymes such as xylanase and other hemicellulases, which break down cell tissues making them available to the fungus. During this stage, the pathogen also produces its asexual spores in the lesions to reproduce and disseminate more propagules for continued survival in the soil. In addition to its normal infection process, studies have shown that Thielaviopsis basicola and its pathogenesis are synergistically linked to a fortuitous coinfection process involving Meloidogyne incognita nematodes when the two are present in the same soil. It has been observed that the infection of host tissues by Meloidogyne incognita facilitates the infection of Thielaviopsis basicola into the root and vascular tissues, effectively allowing the fungal pathogen to optimize infection even when environmental conditions are suboptimal.
Importance
Thielaviopsis basicola was discovered in the mid-1800s and has remained an important plant pathogen affecting ornamental and agricultural plants in over 31 countries around the world. The pathogen is known to stunt or delay maturity in the species it parasitizes, which, coupled with environmental limitations, can lead to severe economic losses. It has been observed that black root rot can delay plant maturity for up to a month and result in over a 40% yield reduction in the affected crop. One crop that is affected by Thielaviopsis basicola and that is of significant economic importance is cotton. In the United States alone, between the years 1995 and 2005, the total annual loss in revenue due to diseases in the cotton crop was $897 million. Thielaviopsis basicola was a significant contributor to that economic loss. In other parts of the world, such as in major cotton producer Australia, Thielaviopsis basicola has a very severe economic impact as well. In Australia, the disease was initially observed in sweet peas in the 1930s. However, black root rot spread to a range of cultivated hosts, especially into Australian cotton production. In fact, surveys taken in 2010 and 2011 of Australian agriculture statistics reported black root rot to be present in 93% of farms and 83% of fields studied. Of the fields affected, yield losses have reached 1.5 bales per acre. The national average of cotton production per hectare in Australia is about 10 bales, so a loss of 1.5 bales per acre (or roughly 3 bales per hectare) to black root rot adds up to a significant loss. In addition to cotton, carrot, lupin, cabbage, clover, and tobacco are all crops cultivated in many different countries that suffer from black root rot. Some important ornamental crops affected by black root rot include: Begonia sp. Daphne cneorum, poinsettia, African daisy, pansy, marigold, and petunia; the list is quite extensive. However, cultural practices have led to the eradication of this disease in many ornamental crops, including poinsettia. During the 1950s and 1960s, poinsettia production was ravaged by black root rot disease. Despite faltering, once the use of soil mixes was traded for soilless alternatives throughout the floriculture industry, black root rot was no longer a threat to poinsettias. Thielaviopsis basicola (black root rot) has been and will remain a significant threat to crops grown globally in both agricultural and horticultural systems.
Disease cycle
Thielaviopsis basicola is a soil inhabiting disease. The pathogen typically colonizes root tissue in the first two to eight weeks of crop growth. This causes cortical cell death which gives a brown to blackened appearance in the roots. The death of root cells also reduces development of new tissue in both roots and shoots. Once the fungus has successfully infected, it grows vegetatively via hyphae and produces the two types of spores. In this particular situation, state means imperfect form of the fungi. The "chalara state produces endospores (conidia) and the Thielavopsis produces aleuriospores (chlamydospores). Chlamydospores survive in soil for many years". During wet and cool soil the spores will germinate. It is most "severe from 55° to 61°F, while only a trace of disease develops at 86°F. Alkaline soil favors the disease, which can be prevented at pH 4.8 and greatly reduced at pH 5.5 or below". The fungus can "spread via vectors including- fungus gnats and shore flies, from infected roots to healthy roots if they come into contact with each other and when spores (conidia) are splashed from pot to pot when watered".
Management
Cultural Practices and Mechanical Measures
The first and foremost strategy for controlling T. basicola at the first sign of disease should be cultural control including- "maintaining a soil pH below 5.6, removing and destroying all diseased plants, using soil-less media, sterilizing equipment, keeping work areas clean, and controlling fungus gnats and shore flies. Fungus gnats and shore flies can be vectors; therefore, controlling these pests can lead to minimizing the spread of the fungus". In addition, "crop rotation is recommended for management of black root rot. Soil fumigants, such as chloropicrin, can be helpful for controlling seedbed and sterol inhibitors". Furthermore, "to avoid contamination of plants and potting media, greenhouse floors and walkways should be lightly misted with water to cut down on airborne dust transmission of T. basicola during cleaning operations". At the end of the "growing season, doing a thorough clean-up of the greenhouse can be beneficial because it reduces the possibility of the fungus surviving as a resistant chlamydospores on the soil floor and in wooden benches".
Disease Resistance
Disease resistance can be naturally coded in the genome of the host itself and induced via natural or artificial means, artificially introduced via a number of transgenic or breeding measures, and/or mutually associated with beneficial microbes found within soil ecosystems. Most, if not all, vascular plants utilize a system of defense, which consists of PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). Following localized infection and the influx of associated pathogen stimulants, the aforementioned immune system responses trigger systemic acquired resistance (SAR), which sets off a cascade of defense signaling throughout the plant to initiate defense strategies at distal locations targeted to attack any recognized foreign pathogens. However, even with these innate lines of defense, the pathogen often prevails. This calls for selective breeding, genetic manipulation, or other novel biological control methods. Assessing varieties/cultivars for disease resistance and breeding for selected resistance traits is an important management method utilized by growers and breeders in the fight against Thielaviopsis basicola. Commercially available resistant species of plants, include select varieties of Japanese holly (among other species of holly) and woody plants such as boxwood and barberry. However, in some important crops like cotton, no commercially viable cultivars have been bred with sufficient resistance against black root rot. Interestingly, in Australia, researchers have identified diploid cotton species displaying marked resistance against black root rot, yet cross-breeding these traits into viable commercial crops has proven to be difficult. Similarly, researchers in Poland have uncovered innate disease resistance in the germplasm of a wild-type relative of Nicotiana tabacum called Nicotiana glauca. Moreover, disease resistance genes derived from Nicotiana debneyi (a relative of the previously mentioned tobacco species) have successfully been incorporated into tobacco varieties displaying resilience to multiple races of Thielaviopsis basicola. That being said, selective variety breeding is not the only source of resistance to black root rot in modern plant pathology. Transgenic methods of disease management offer promising new avenues scientists can take to aid in adapting plants to increasingly virulent pathogens. One such mechanism includes the manipulation of the expression of the NPR1 gene in the host plant defense genome sequences. By over-expressing NPR1 genes transgenically in host plants such as cotton, scientists were able to increase the induction of PR genes like PR1 and LIPOXYGENASE1, which led to enhanced resistance by improving yield and limiting stunting. In addition to genetic tools, inventive plant pathologists are exploring other novel methods of control, which include beneficial microbes and biological control agents (BCAs), among many others. Symbiotic associations between arbuscular mycorrhizal fungi and plant roots are well-documented, yet scientists studying host-plant defense have discovered this association may be more arcane than previously thought. Some researchers suggest this association extends to the realm of disease resistance and defense. This phenomenon was analyzed in research conducted by German scientists who studied the transcript expression of defense related genes in Petunia hybrida when they were exposed to Thielaviopsis basicola and also colonized by arbuscular mycorrhizal fungal networks in their rhizosphere. They found that the arbuscular mycorrhiza (AM) symbiosis functioned as a first line of defense by antagonizing the pathogenic fungus before it could ever induce a defense response in the host itself. Thus, it is not inconceivable that control measures involving biotic compliments, such as AM, may be used in the future to control for disease presence in agricultural fields without the use of deleterious chemicals and/or genetic meddling.
Infected plants
See:
List of alfalfa diseases
List of African daisy diseases
List of carrot diseases
List of chickpea diseases
List of cineraria diseases
List of citrus diseases
List of cotton diseases
List of cucurbit diseases
List of cyclamen diseases
List of flax diseases
List of fuchsia diseases
List of geranium diseases
List of lentil diseases
List of pea diseases
List of peanut diseases
List of poinsettia diseases
List of red clover diseases
List of soybean diseases
List of tobacco diseases
List of tomato diseases
List of verbena diseases
References
Fungal plant pathogens and diseases
Carrot diseases
Fungal citrus diseases
Cotton diseases
Fiber plant diseases
Peanut diseases
Soybean diseases
Tobacco diseases
Tomato diseases
Food plant pathogens and diseases
Ornamental plant pathogens and diseases
Microascales
Fungi described in 1912
Fungus species | Thielaviopsis basicola | [
"Biology"
] | 3,663 | [
"Fungi",
"Fungus species"
] |
11,063,381 | https://en.wikipedia.org/wiki/Chondrostereum%20purpureum | Chondrostereum purpureum is a fungal plant pathogen which causes Silver leaf disease of trees . It attacks most species of the rose family Rosaceae, particularly the genus Prunus. The disease is progressive and often fatal. The common name is taken from the progressive silvering of leaves on affected branches. It is spread by airborne spores landing on freshly exposed sapwood. For this reason cherries and plums are pruned in summer, when spores are least likely to be present and when disease is visible. Silver Leaf can also happen on poming fruits like apples and pears. Plums are especially vulnerable.
In the past the name Stereum purpureum Pers. was widely used for this fungus, but according to modern taxonomy it is only distantly related to Stereum, actually belonging to order Agaricales whereas Stereum is in order Russulales.
Characteristics
It is a pathogen of various, mostly deciduous trees including species of Acer, Aesculus, Alnus, Betula, Crataegus, Fagus, Larix, Malus, Ostrya, Picea, Populus, Prunus, Salix, and Sorbus.
After starting as just a crust on the wood, the fruiting structure develops undulating intergrowing brackets up to about 3 cm broad, which have a tough rubbery texture. The edges and fertile lower surfaces show a fairly vivid violet colour while the fungus is growing, and the upper surfaces have a grey aspect (sometimes with zonation and usually a lighter edge) and are covered with whitish hairs. After a week or two the fructification dries out, becomes brittle, and turns a drab brown or beige. Infected wood can be recognized because it is stained a darker tint.
The spores are rounded cylinders approximately 5–8 μm x 3–4 μm in size. The hyphal structure is monomitic with clamp connections.
It is often found on old stumps and dead wood, but can also be a serious parasite of living trees. As well as plum trees it attacks many other broad-leafed species (other Prunus, apple, pear, willow, poplar, maple, hornbeam, plane, oak, elm, lilac, and many others). Occasionally it also infects conifers (fir, spruce, Thuja, ...). Geographically it is roughly just as widespread as its hosts; it is common in woods, orchards and tree plantations in temperate climates.
Mycoherbicide
Chondrostereum purpureum is commercially available as a method of combatting forest 'weed trees' such as aspens, beech, birches, maples, pin cherry, poplars, and other species. The fungus is applied directly to the weed trees in a nutrient paste which can be stored and handled conveniently.
The first regulatory approval was granted in 2001 to Myco-Forestis Corporation and targeted species "including birch, pin-cherry, poplar/aspen, red maple, sugar maple, and speckled alder in the Boreal and Mixed forest regions of Canada, east of the Rocky Mountains". It had not been reported as of 2001 to cause any diseases in coniferous tree species.
According to a 2007 regulatory decision of the Canadian Pest Management Regulatory Agency, the use of this control method in paste form on Sitka spruce and red alder will only have a limited impact on non-target trees since the fungal spores are ubiquitous anyway and healthy trees are resistant to attack.
As a human pathogen
A single case report confirmed human infection with Chondrostereum purpureum in a non immunocompromised man who had been working with infected plant material. It was resolved by treating him with antifungal medication, but indicates potential for a broader host range for plant fungus than previously believed.
Similar species
Amylostereum areolatum is considered to be similar, and usually has moss covering its cap.
References
Further reading
External links
Royal Horticultural Society advice on the treatment of infected trees.
Fungal tree pathogens and diseases
Parasitic fungi
Mycoherbicides
Fungi of Europe
Cyphellaceae
Fungi described in 1794
Taxa named by Christiaan Hendrik Persoon
Fungus species | Chondrostereum purpureum | [
"Biology"
] | 874 | [
"Fungi",
"Fungus species"
] |
11,063,389 | https://en.wikipedia.org/wiki/Venturia%20carpophila | Venturia carpophila is a species of fungus in the family Venturiaceae. A plant pathogen, it causes freckle, black spot, peach scab or black scab of peach. It has a cosmopolitan distribution. The species was described as new to science in 1961 by the Australian mycologist Eileen E. Fisher.
References
Fungi described in 1966
Venturiaceae
Fungal plant pathogens and diseases
Stone fruit tree diseases
Fungus species | Venturia carpophila | [
"Biology"
] | 89 | [
"Fungi",
"Fungus species"
] |
11,063,398 | https://en.wikipedia.org/wiki/Colletotrichum%20acutatum | Colletotrichum acutatum is a plant pathogen and endophyte. It is the organism that causes the most destructive fungal disease, anthracnose, of lupin species worldwide.
It also causes the disease postbloom fruit drop on many varieties of citrus, especially Valencia and navel oranges in Florida.
Host and symptoms
Colletotrichum acutatum has a broad host range, but is most important in strawberries. The pathogen causes black spot of fruit, but can also be seen attacking the plant at its crowns, roots and leaves. After planting, stunting and yellowing as well as wilting may occur. General symptoms of the disease in other plants can also be seen on flowers, petioles, and roots. Stems are also a prominent place to see symptoms. Lesions on the stem can appear dark colored, oval shaped, and possibly have immersed spots located on petioles and runners. Once C.acutatum infects these parts of the plant, it can cause other diseases to unfold such as crown root rot, defoliation, bloom blight and fruit rot. Unfortunately, the most significant loss can be seen once the fruit is attacked. If the fruit is infected it will develop small brown spots (green fruit) or black spots (red fruit) and can expand throughout the fruits' surface.
Environment
This pathogen has a wide geographical distribution. Strains of the pathogen are present throughout various climates worldwide. Temperature can affect how symptoms appear on the host. Optimal temperature for growth of C. acutatum is 25 degrees Celsius. For instance, in weather with high humidity, orange colored spores appear on the hosts' lesions. Specifically in strawberries, this disease appears to be more harmful in warm climates. Transference of disease occurs when conidia are spread by water, specifically rain or irrigation water. Another way of contamination is from infected equipment or wind.
Taxonomic history
Historically fungi that were pathogenic on different plants were often given different names, even though they often had near identical morphology. In 1957 Josef Adolf von Arx synonymized about 600 fungal species names as Colletotrichum gloeosporioides. In 1965 C. gloeosporioides strains that had acute conidia and slower growth were renamed as Colletotrichum acutatum. With the invention of easy and affordable DNA sequencing technologies, species identification switched from being based on morphology to being based on a combination of morphology and molecular phylogenetics. In 2012 the C. acutatum species was split up into more than two dozen new species, and is now referred to as the C. acutatum species complex. The C. acutatum species complex still includes a species called C. acutatum, but it is now defined more narrowly than it had been from 1965 to 2012.
As a Biocontrol Agent
This fungus attacks the Australian species Hakea sericea in South Africa, where this shrub is an invasive species. For this reason, local researchers have been investigating the application of this fungus as a means of biological control.
Pest Management
Cultural control
Sanitation is critical in controlling the disease. Thoroughly washing plants by removing all the dirt could reduce occurrence. This method has also been demonstrated to reduce pests such has anthracnose. Proper sanitation of equipment could reduce exposure of contracting the pathogen. This would be equipment used in transportation, packing, storage, etc. Crop rotation, as well as the removal of weeds is also helpful in reducing the pathogen in the soil. Removing weeds from the field is a critical step; the pathogen on the dead weeds could still produce spores.
Chemical control
A common method of control for this disease is the use of fungicides. Fungicides are soil fumigants that are used to decrease amount of inoculum in the soil. Chloropicrin, a fungicide, has seen good results with regular application. Unfortunately, relying on just one fungicide heavily can increase the disease's tolerance. Moreover, the timing of the application is very crucial. With poorly timed applications, there could be an increase of disease severity due to the disturbance of natural biocontrol mechanisms and increased crop susceptibility. Pest control is also crucial in the containment of the disease. After rainfall or irrigation, anthracnose symptoms may occur. Using foliar fungicide can help prevent spread of the disease and minimize anthracnose.
References
acutatum
Fungal plant pathogens and diseases
Fungal citrus diseases
Fungi described in 1965
Fungus species | Colletotrichum acutatum | [
"Biology"
] | 923 | [
"Fungi",
"Fungus species"
] |
11,063,407 | https://en.wikipedia.org/wiki/Gibberella%20bresadolae | Gibberella bresadolae is a fungal plant pathogen.
References
Fungal plant pathogens and diseases
Hypocreales
Fungi described in 1968
Fungus species | Gibberella bresadolae | [
"Biology"
] | 34 | [
"Fungi",
"Fungus species"
] |
11,063,415 | https://en.wikipedia.org/wiki/Gibberella%20avenacea | Gibberella avenacea is a fungus that infects plants.
References
External links
USDA ARS Fungal Database
avenacea
Fungal plant pathogens and diseases
Fungi described in 1967
Fungus species | Gibberella avenacea | [
"Biology"
] | 40 | [
"Fungi",
"Fungus species"
] |
11,063,438 | https://en.wikipedia.org/wiki/Gibberella%20pulicaris | Gibberella pulicaris is a fungal plant pathogen infecting several hosts including potato, strawberry, hop, alfalfa and Douglas-fir.
Synonyms
Sphaeria pulicaris Fr., Mykologische Hefte 2: 37 (1823) [MB#239256]
Gibbera pulicaris (Fr.) Fr., Summa vegetabilium Scandinaviae 2: 402 (1849) [MB#190097]
Botryosphaeria pulicaris (Fr.) Ces. & De Not. (1863) [MB#184344]
Nectria pulicaris (Fr.) Tul. & C. Tul., Selecta Fungorum Carpologia: Nectriei- Phacidiei- Pezizei 3: 63 (1865) [MB#465479]
Cucurbitaria pulicaris (Fr.) Quél., Mémoires de la Société d'Émulation de Montbéliard sér. 2, 5: 511 (1875) [MB#504675]
Sphaeria cyanogena Desm., Annales des Sciences Naturelles Botanique sér. 3, 10: 352 (1848) [MB#199264]
References
http://www.mycobank.org/Biolomics.aspx?Table=Mycobank&MycoBankNr_=211541
External links
Index Fungorum
USDA ARS Fungal Database
pulicaris
Fungal plant pathogens and diseases
Food plant pathogens and diseases
Fungal conifer pathogens and diseases
Fungal strawberry diseases
Potato diseases
Fungi described in 1877
Taxa named by Elias Magnus Fries
Fungus species | Gibberella pulicaris | [
"Biology"
] | 351 | [
"Fungi",
"Fungus species"
] |
11,063,889 | https://en.wikipedia.org/wiki/Marie%20Boivin | Marie-Anne Victoire Gillain Boivin (9 April 1773 – 16 May 1841) was a French midwife, inventor, and obstetrics writer. Mme Boivin has been called one of the most important women in medicine in the 19th century. Boivin invented a new pelvimeter and a vaginal speculum, and the medical textbooks that she wrote were translated to different languages and used for 150 years.
Background
Marie Anne Victoire Gillain was born in 1773 at Versailles. She was educated by nursing nuns at a nunnery in Étampes, where her talents attracted the attention of Madame Élisabeth, sister of King Louis XVI. When the nunnery was destroyed during the French Revolution, she spent three years studying anatomy and midwifery.
Her medical studies was interrupted when she married a government bureaucrat, Louis Boivin, in 1797.
Louis Boivin died shortly thereafter, leaving her with a daughter and little money. She became a midwife at a local hospital, and in 1801 became its superintendent. In that role she convinced Jean-Antoine Chaptal to add a special school of obstetrics. Mme Boivin continues to study in the medical field. Mme Boivin then became Marie-Louise Lachapelle's student, assistant, and friend in Paris. Mme Boivin received her diploma in 1800, and stayed at Versailles to practice.
Career
When her husband died, she returned to Paris to assist Mme Lachapelle at La Maternite. During that time, Mme Boivin developed a close relationship with Dr. Chaussier. Because of professional jealousy of her colleague and friend Mme Lachapelle, Mme Boivin resigned her position in 1811, and she rejected the offer of Mme Lachapelle's position after the latter died in 1822. She accepted a position for servants' wages at a Paris hospital for fallen women. In the subsequent years she served as co-director or director at a number of hospitals, including the General Hospital for Seine-et-Oise (1814), a temporary military hospital (1815), the Hospice de la Maternité, and the Maison Royale de Santé. She was also member of several medical societies. She has published articles and books about her own case and her uterine speculum. Her Mémorial de l'art des accouchements (1817) went through several editions and became a standard textbook.
Contribution
Mme Boivin invented a new pelvimeter, and a vaginal speculum which was used to dilate the vagina and the examination of the cervix. Her invention helped not only her female patients, but also medical practitioners. She is one of the first to use stethoscope to listen to the fetal heart. She was given credit for discovering the cause of certain types of bleeding, the cause of miscarriages and diseases of the placenta and uterus. Radcliffe stated that she 'was undertaking surgical treatments which in other countries were the prerogative of the men.' Mme Boivin was also one of the first surgeons to amputate the cervix uteri for a cancerous growth. Because Mme Boivin was an innovative and skillful gynecological surgeon, German universities became more opened to the idea of women becoming skilled in gynecological surgery.
From 1812 to 1823, Mme Boivin had many publications, both original and translations. Her first edition of Memorial de l'Art des Accouchemens was published in 1812. It included notes she had taken from Marie-Louise Lachapelle's teaching, and the book was used as a handbook for medical students and midwives. The third edition of Memorial de l'Art des Accouchemens was translated into several European languages. Her work of the causes of abortion received a commendation from the Royal Society of Medicine at Bordeaux. She also has published articles about her own cases and her uterine speculum in the bulletins de la faculta de Medecine and Amcademie royale de medecine de Paris. Mme Boivin then focused on more advanced writings in gynecology, such as Nouveau Traité des Hemorragies de l'Uterus and Traité de Maladies de l'Uterus et des Annexes, which was her most important work. It included 41 plates and 116 figures which she colored herself, and superseded the textbook which had been in use for 150 years.
Selected work
- Memorial de l'Art des Accouchmens (handbook for medical student and midwives), 1812
- Nouveau traité des hémorragies de l'utérus (bleeding from the uterus), 1818
- Mémorial de l'art des accouchemens (handbook for medical students, third edition), 1824
- Recherches sur une des causes les plus frequentes et la moins connue de l'avortement (the Most Frequent and Least Known Causes of Abortion), 1828
- Observations et reflexions sur les cas d'absorption de placenta (the case of absorption of the placenta), 1829
- Traité des Maladies de l'utérus et des annexes (Diseases of the uterus), 1833
Honors
- Prussia Golden Medal of Civil Merit, 1814
- Honorary MD degree of the University of Marburg in Germany, 1827
- Commendation from the Royal Society of Medical in Bordeaux
- Member of several medical societies
- A nursery named after Mme Boivin at her home town, Versailles
References
June K. Burton, "Preeminent female teachers: Mme Lachapelle and Mme Boivin", p. 98–106. Napoleon and the Woman Question: Discourses of the Other Sex in French Education, Medicine, and Medical Law 1799-1815, Texas Tech University Press, 2007 ,
Further reading
Oakes, Elizabeth H. "Boivin, Marie-Anne Victoire Gallain". Encyclopedia of World Scientists. Infobase Publishing, 2007
External links
1773 births
1841 deaths
People from Montreuil, Seine-Saint-Denis
French midwives
French science writers
French women writers
Women science writers
Women inventors
19th-century French inventors | Marie Boivin | [
"Technology"
] | 1,280 | [
"Women science writers",
"Women in science and technology"
] |
11,063,933 | https://en.wikipedia.org/wiki/Rule%20184 | Rule 184 is a one-dimensional binary cellular automaton rule, notable for solving the majority problem as well as for its ability to simultaneously describe several, seemingly quite different, particle systems:
Rule 184 can be used as a simple model for traffic flow in a single lane of a highway, and forms the basis for many cellular automaton models of traffic flow with greater sophistication. In this model, particles (representing vehicles) move in a single direction, stopping and starting depending on the cars in front of them. The number of particles remains unchanged throughout the simulation. Because of this application, Rule 184 is sometimes called the "traffic rule".
Rule 184 also models a form of deposition of particles onto an irregular surface, in which each local minimum of the surface is filled with a particle in each step. At each step of the simulation, the number of particles increases. Once placed, a particle never moves.
Rule 184 can be understood in terms of ballistic annihilation, a system of particles moving both leftwards and rightwards through a one-dimensional medium. When two such particles collide, they annihilate each other, so that at each step the number of particles remains unchanged or decreases.
The apparent contradiction between these descriptions is resolved by different ways of associating features of the automaton's state with particles.
The name of Rule 184 is a Wolfram code that defines the evolution of its states. The earliest research on Rule 184 is by and . In particular, Krug and Spohn already describe all three types of particle system modeled by Rule 184.
Definition
A state of the Rule 184 automaton consists of a one-dimensional array of cells, each containing a binary value (0 or 1). In each step of its evolution, the Rule 184 automaton applies the following rule to each of the cells in the array, simultaneously for all cells, to determine the new state of the cell:
An entry in this table defines the new state of each cell as a function of the previous state and the previous values of the neighboring cells on either side.
The name for this rule, Rule 184, is the Wolfram code describing the state table above: the bottom row of the table, 10111000, when viewed as a binary number, is equal to the decimal number 184.
The rule set for Rule 184 may also be described intuitively, in several different ways:
At each step, whenever there exists in the current state a 1 immediately followed by a 0, these two symbols swap places. Based on this description, call Rule 184 a deterministic version of a "kinetic Ising model with asymmetric spin-exchange dynamics".
At each step, if a cell with value 1 has a cell with value 0 immediately to its right, the 1 moves rightwards leaving a 0 behind. A 1 with another 1 to its right remains in place, while a 0 that does not have a 1 to its left stays a 0. This description is most apt for the application to traffic flow modeling.
If a cell has state 0, its new state is taken from the cell to its left. Otherwise, its new state is taken from the cell to its right. That is, each cell can be implemented by a two-way demultiplexer with the two adjacent cells being inputs, and the cell itself acting as the selector line. Each cell's next state is determined by the demultiplexer's output. This operation is closely related to a Fredkin gate.
Dynamics and majority classification
From the descriptions of the rules above, two important properties of its dynamics may immediately be seen. First, in Rule 184, for any finite set of cells with periodic boundary conditions, the number of 1s and the number of 0s in a pattern remains invariant throughout the pattern's evolution. Rule 184 and its reflection are the only nontrivial elementary cellular automata to have this property of number conservation. Similarly, if the density of 1s is well-defined for an infinite array of cells, it remains invariant as the automaton carries out its steps. And second, although Rule 184 is not symmetric under left-right reversal, it does have a different symmetry: reversing left and right and at the same time swapping the roles of the 0 and 1 symbols produces a cellular automaton with the same update rule.
Patterns in Rule 184 typically quickly stabilize, either to a pattern in which the cell states move in lockstep one position leftwards at each step, or to a pattern that moves one position rightwards at each step. Specifically, if the initial density of cells with state 1 is less than 50%, the pattern stabilizes into clusters of cells in state 1, spaced two units apart, with the clusters separated by blocks of cells in state 0. Patterns of this type move rightwards. If, on the other hand, the initial density is greater than 50%, the pattern stabilizes into clusters of cells in state 0, spaced two units apart, with the clusters separated by blocks of cells in state 1, and patterns of this type move leftwards. If the density is exactly 50%, the initial pattern stabilizes (more slowly) to a pattern that can equivalently be viewed as moving either leftwards or rightwards at each step: an alternating sequence of 0s and 1s.
The majority problem is the problem of constructing a cellular automaton that, when run on any finite set of cells, can compute the value held by a majority of its cells.
In a sense, Rule 184 solves this problem, as follows. if Rule 184 is run on a finite set of cells with periodic boundary conditions, with an unequal number of 0s and 1s, then each cell will eventually see two consecutive states of the majority value infinitely often, but will see two consecutive states of the minority value only finitely many times. The majority problem cannot be solved perfectly if it is required that all cells eventually stabilize to the majority state but the Rule 184 solution avoids this impossibility result by relaxing the criterion by which the automaton recognizes a majority.
Traffic flow
If one interprets each 1-cell in Rule 184 as containing a particle, these particles behave in many ways similarly to automobiles in a single lane of traffic: they move forward at a constant speed if there is open space in front of them, and otherwise they stop. Traffic models such as Rule 184 and its generalizations that discretize both space and time are commonly called particle-hopping models. Although very primitive, the Rule 184 model of traffic flow already predicts some of the familiar emergent features of real traffic: clusters of freely moving cars separated by stretches of open road when traffic is light, and waves of stop-and-go traffic when it is heavy.
It is difficult to pinpoint the first use of Rule 184 for traffic flow simulation, in part because the focus of research in this area has been less on achieving the greatest level of mathematical abstraction and more on verisimilitude: even the earlier papers on cellular automaton based traffic flow simulation typically make the model more complex in order to more accurately simulate real traffic. Nevertheless, Rule 184 is fundamental to traffic simulation by cellular automata. , for instance, state that "the basic cellular automaton model describing a one-dimensional traffic flow problem is rule 184." writes "Much work using CA models for traffic is based on this model." Several authors describe one-dimensional models with vehicles moving at multiple speeds; such models degenerate to Rule 184 in the single-speed case. extend the Rule 184 dynamics to two-lane highway traffic with lane changes; their model shares with Rule 184 the property that it is symmetric under simultaneous left-right and 0-1 reversal. describe a two-dimensional city grid model in which the dynamics of individual lanes of traffic is essentially that of Rule 184. For an in-depth survey of cellular automaton traffic modeling and associated statistical mechanics, see and .
When viewing Rule 184 as a traffic model, it is natural to consider the average speed of the vehicles. When the density of traffic is less than 50%, this average speed is simply one unit of distance per unit of time: after the system stabilizes, no car ever slows. However, when the density is a number ρ greater than 1/2, the average speed of traffic is . Thus, the system exhibits a second-order kinetic phase transition at . When Rule 184 is interpreted as a traffic model, and started from a random configuration whose density is at this critical value , then the average speed approaches its stationary limit as the square root of the number of steps. Instead, for random configurations whose density is not at the critical value, the approach to the limiting speed is exponential.
Surface deposition
As shown in the figure, and as originally described by , Rule 184 may be used to model deposition of particles onto a surface. In this model, one has a set of particles that occupy a subset of the positions in a square lattice oriented diagonally (the darker particles in the figure). If a particle is present at some position of the lattice, the lattice positions below and to the right, and below and to the left of the particle must also be filled, so the filled part of the lattice extends infinitely downward to the left and right. The boundary between filled and unfilled positions (the thin black line in the figure) is interpreted as modeling a surface, onto which more particles may be deposited. At each time step, the surface grows by the deposition of new particles in each local minimum of the surface; that is, at each position where it is possible to add one new particle that has existing particles below it on both sides (the lighter particles in the figure).
To model this process by Rule 184, observe that the boundary between filled and unfilled lattice positions can be marked by a polygonal line, the segments of which separate adjacent lattice positions and have slopes +1 and −1. Model a segment with slope +1 by an automaton cell with state 0, and a segment with slope −1 by an automaton cell with state 1. The local minima of the surface are the points where a segment of slope −1 lies to the left of a segment of slope +1; that is, in the automaton, a position where a cell with state 1 lies to the left of a cell with state 0. Adding a particle to that position corresponds to changing the states of these two adjacent cells from 1,0 to 0,1, so advancing the polygonal line. This is exactly the behavior of Rule 184.
Related work on this model concerns deposition in which the arrival times of additional particles are random, rather than having particles arrive at all local minima simultaneously. These stochastic growth processes can be modeled as an asynchronous cellular automaton.
Ballistic annihilation
Ballistic annihilation describes a process by which moving particles and antiparticles annihilate each other when they collide. In the simplest version of this process, the system consists of a single type of particle and antiparticle, moving at equal speeds in opposite directions in a one-dimensional medium.
This process can be modeled by Rule 184, as follows. The particles are modeled as points that are aligned, not with the cells of the automaton, but rather with the interstices between cells. Two consecutive cells that both have state 0 model a particle at the space between these two cells that moves rightwards one cell at each time step. Symmetrically, two consecutive cells that both have state 1 model an antiparticle that moves leftwards one cell at each time step. The remaining possibilities for two consecutive cells are that they both have differing states; this is interpreted as modeling a background material without any particles in it, through which the particles move. With this interpretation, the particles and antiparticles interact by ballistic annihilation: when a rightwards-moving particle and a leftwards-moving antiparticle meet, the result is a region of background from which both particles have vanished, without any effect on any other nearby particles.
The behavior of certain other systems, such as one-dimensional cyclic cellular automata, can also be described in terms of ballistic annihilation. There is a technical restriction on the particle positions for the ballistic annihilation view of Rule 184 that does not arise in these other systems, stemming from the alternating pattern of the background: in the particle system corresponding to a Rule 184 state, if two consecutive particles are both of the same type they must be an odd number of cells apart, while if they are of opposite types they must be an even number of cells apart. However this parity restriction does not play a role in the statistical behavior of this system.
uses a similar but more complicated particle-system view of Rule 184: he not only views alternating 0–1 regions as background, but also considers regions consisting solely of a single state to be background as well. Based on this view he describes seven different particles formed by boundaries between regions, and classifies their possible interactions. See for a more general survey of the cellular automaton models of annihilation processes.
Context-free parsing
In his book A New Kind of Science, Stephen Wolfram points out that rule 184, when run on patterns with density 50%, can be interpreted as parsing the context-free language describing strings formed from nested parentheses. This interpretation is closely related to the ballistic annihilation view of rule 184: in Wolfram's interpretation, an open parenthesis corresponds to a left-moving particle while a close parenthesis corresponds to a right-moving particle.
See also
Rule 30, Rule 90, and Rule 110, other one-dimensional cellular automata with different behavior
Notes
References
External links
Rule 184 in Wolfram's atlas of cellular automata
Cellular automaton rules
Lattice models
Wolfram code
Traffic flow | Rule 184 | [
"Physics",
"Materials_science"
] | 2,854 | [
"Statistical mechanics",
"Condensed matter physics",
"Lattice models",
"Computational physics"
] |
11,063,979 | https://en.wikipedia.org/wiki/Tangent%20measure | In measure theory, tangent measures are used to study the local behavior of Radon measures, in much the same way as tangent spaces are used to study the local behavior of differentiable manifolds. Tangent measures (introduced by David Preiss in his study of rectifiable sets) are a useful tool in geometric measure theory. For example, they are used in proving Marstrand's theorem and Preiss' theorem.
Definition
Consider a Radon measure μ defined on an open subset Ω of n-dimensional Euclidean space Rn and let a be an arbitrary point in Ω. We can "zoom in" on a small open ball of radius r around a, Br(a), via the transformation
which enlarges the ball of radius r about a to a ball of radius 1 centered at 0. With this, we may now zoom in on how μ behaves on Br(a) by looking at the push-forward measure defined by
where
As r gets smaller, this transformation on the measure μ spreads out and enlarges the portion of μ supported around the point a. We can get information about our measure around a by looking at what these measures tend to look like in the limit as r approaches zero.
Definition. A tangent measure of a Radon measure μ at the point a is a second Radon measure ν such that there exist sequences of positive numbers ci > 0 and decreasing radii ri → 0 such that
where the limit is taken in the weak-∗ topology, i.e., for any continuous function φ with compact support in Ω,
We denote the set of tangent measures of μ at a by Tan(μ, a).
Existence
The set Tan(μ, a) of tangent measures of a measure μ at a point a in the support of μ is nonempty on mild conditions on μ. By the weak compactness of Radon measures, Tan(μ, a) is nonempty if one of the following conditions hold:
μ is asymptotically doubling at a, i.e.
μ has positive and finite upper density, i.e. for some .
Properties
The collection of tangent measures at a point is closed under two types of scaling. Cones of measures were also defined by Preiss.
The set Tan(μ, a) of tangent measures of a measure μ at a point a in the support of μ is a cone of measures, i.e. if and , then .
The cone Tan(μ, a) of tangent measures of a measure μ at a point a in the support of μ is a d-cone or dilation invariant, i.e. if and , then .
At typical points in the support of a measure, the cone of tangent measures is also closed under translations.
At μ almost every a in the support of μ, the cone Tan(μ, a) of tangent measures of μ at a is translation invariant, i.e. if and x is in the support of ν, then .
Examples
Suppose we have a circle in R2 with uniform measure on that circle. Then, for any point a in the circle, the set of tangent measures will just be positive constants times 1-dimensional Hausdorff measure supported on the line tangent to the circle at that point.
In 1995, Toby O'Neil produced an example of a Radon measure μ on Rd such that, for μ-almost every point a ∈ Rd, Tan(μ, a) consists of all nonzero Radon measures.
Related concepts
There is an associated notion of the tangent space of a measure. A k-dimensional subspace P of Rn is called the k-dimensional tangent space of μ at a ∈ Ω if — after appropriate rescaling — μ "looks like" k-dimensional Hausdorff measure Hk on P. More precisely:
Definition. P is the k-dimensional tangent space of μ at a if there is a θ > 0 such that
where μa,r is the translated and rescaled measure given by
The number θ is called the multiplicity of μ at a, and the tangent space of μ at a is denoted Ta(μ).
Further study of tangent measures and tangent spaces leads to the notion of a varifold.
References
Measures (measure theory) | Tangent measure | [
"Physics",
"Mathematics"
] | 865 | [
"Measures (measure theory)",
"Quantity",
"Physical quantities",
"Size"
] |
11,064,788 | https://en.wikipedia.org/wiki/Prismatic%20uniform%20polyhedron | In geometry, a prismatic uniform polyhedron is a uniform polyhedron with dihedral symmetry. They exist in two infinite families, the uniform prisms and the uniform antiprisms. All have their vertices in parallel planes and are therefore prismatoids.
Vertex configuration and symmetry groups
Because they are isogonal (vertex-transitive), their vertex arrangement uniquely corresponds to a symmetry group.
The difference between the prismatic and antiprismatic symmetry groups is that Dph has the vertices lined up in both planes, which gives it a reflection plane perpendicular to its p-fold axis (parallel to the {p/q} polygon); while Dpd has the vertices twisted relative to the other plane, which gives it a rotatory reflection. Each has p reflection planes which contain the p-fold axis.
The Dph symmetry group contains inversion if and only if p is even, while Dpd contains inversion symmetry if and only if p is odd.
Enumeration
There are:
prisms, for each rational number p/q > 2, with symmetry group Dph;
antiprisms, for each rational number p/q > 3/2, with symmetry group Dpd if q is odd, Dph if q is even.
If p/q is an integer, i.e. if q = 1, the prism or antiprism is convex. (The fraction is always assumed to be stated in lowest terms.)
An antiprism with p/q < 2 is crossed or retrograde; its vertex figure resembles a bowtie. If p/q < 3/2 no uniform antiprism can exist, as its vertex figure would have to violate the triangle inequality. If p/q = 3/2 the uniform antiprism is degenerate (has zero height).
Forms by symmetry
Note: The tetrahedron, cube, and octahedron are listed here with dihedral symmetry (as a digonal antiprism, square prism and triangular antiprism respectively), although if uniformly colored, the tetrahedron also has tetrahedral symmetry and the cube and octahedron also have octahedral symmetry.
See also
Uniform polyhedron
Prism (geometry)
Antiprism
References
Cromwell, P.; Polyhedra, CUP, Hbk. 1997, . Pbk. (1999), . p.175
.
External links
Prisms and Antiprisms George W. Hart
Prismatoid polyhedra
Uniform polyhedra | Prismatic uniform polyhedron | [
"Physics"
] | 508 | [
"Uniform polytopes",
"Uniform polyhedra",
"Symmetry"
] |
11,064,816 | https://en.wikipedia.org/wiki/Caffeine-induced%20sleep%20disorder | Caffeine-induced sleep disorder was a psychiatric disorder identified as resulting from overconsumption of the stimulant caffeine.
Caffeine is one of the most widely consumed psychoactive drugs: almost 90% of Americans in a survey consume some type of caffeine each day. "When caffeine is consumed immediately before bedtime or .... throughout the day, sleep onset may be delayed, total sleep time reduced, normal stages of sleep altered, and the quality of sleep decreased." Caffeine reduces slow-wave sleep in the early part of the sleep cycle and can reduce rapid eye movement sleep later in the cycle. Caffeine increases episodes of wakefulness, and high doses in the late evening can increase sleep onset latency. In elderly people, there is an association between use of medication containing caffeine and difficulty in falling asleep.
Official recognition and past criteria
The latest Diagnostic and Statistical Manual of Mental Disorders, DSM-5, does not include caffeine-induced sleep disorder. It does have "Other Caffeine-Induced Disorders" and "Unspecified Caffeine-Related Disorder" which may have linkage with caffeine use.
Previously DSM-4 included criteria for the disorder that there must be a significant inability to sleep which is caused entirely by the physiological effects of caffeine as proven by an examination; if sleeping issues can be accounted for due to a breathing-related sleep disorder, narcolepsy, a circadian rhythm sleep disorder or a mental disorder, then caffeine-induced sleep disorder was not the cause. This condition was seen as causing a notable impairment in functioning.
Similarly the latest International Classification of Diseases, ICD-11, does not include a specific sleep-related caffeine disorder, but does include "sleep-wake disorders" under "Disorders due to use of caffeine, unspecified".
Caffeine and age
Most studies now, find that there is relatively no association between caffeine and its effects on sleep for infants. There was very little difference between mothers who had high caffeine consumption during pregnancy as opposed to mothers who did not have high consumption of caffeine during their pregnancy.
Caffeine in younger children has been found to shorten their sleep duration and increase daytime sleepiness. One study, which looked at children ages six to ten years of age, found that those who consistently consumed caffeine lost about 15 minutes of sleep each night. In most cases where younger children are drinking high amounts of caffeine, parents usually buy their children soft drinks, iced tea, or energy drinks without realizing the amount of caffeine these drinks contain or the implications they have on their children.
30% of adolescent adults in a survey were found to consume caffeine daily. Individuals with higher caffeine consumption, tended to feel an increase in wakefulness after sleep onset, shorter sleep durations, and longer daytime sleep. Those who consumed high amounts of caffeine daily, were found to be 1.9 times more likely to have difficulty sleeping and 1.8 times more likely to feel sleepy in the morning compared to those who consume almost no caffeine. Individuals with higher caffeine consumption felt an increase in wakefulness after sleep onset, shorter sleep durations, and longer daytime sleep. The higher consumption time for adolescent adults tends to be on the weekends, while the lowest consumption is midweek. This is assumed to be from greater social opportunities among adolescence.
Mechanism of caffeine
Caffeine is an adenosine receptor antagonist. This means that caffeine mainly works by occupying adenosine receptors in the brain, specifically, receptors that influence sleep, arousal, and cognition. Once it is in the body, caffeine will persist for several hours, and takes about six hours for one half of the caffeine consumed to be eliminated. When caffeine reaches the brain, it increases the secretion of norepinephrine which is related to the "fight or flight" response. The rise in norepinephrine levels increases activity of neurons in areas of the brain and the symptoms resemble those of a panic attack.
The half-life of caffeine is roughly 3–4 hours in healthy adults, however, it is dependent on a variety of variables such as age, liver function, medications, level of enzymes, pregnancy. This short half-life has been found to help out daytime functioning, but increase the side effect of sleep problems. So, while caffeine has the potential to increase performance, it comes at a cost of sleep deprivation which in its own way can counter the main point of caffeine. Sleep deprivation alone can cause a variety of problems associated with cognitive control and functions. This can include reduced alertness, attention, vigilance, speed of motor functions.
Though caffeine can be shown to decrease the quality of sleep, there is no evidence that caffeine affects all people the same way. In fact, some people report no sleep problems despite regularly consuming caffeine. Regular intake of caffeine may be normal for a person so it is understandable how they may still get satisfactory sleep. This finding shows that caffeine interferes with a modulatory mechanism in sleep regulation rather than a fundamental sleep regulatory brain circuit. Ultimately, regular sleep habits are important in overall quality and timing of sleep.
Caffeine consumption
Overconsumption
Although the maximum daily consumption of caffeine varies with consideration of couple of aspects such as sex, age, race, physical activity and smoking, excessive ingestion of caffeine can lead to a state of intoxication. This period of intoxication is characterized by restlessness, agitation, excitement, rambling thought or speech, and even insomnia. Even doses of caffeine relating to just one cup of coffee can increase sleep latency and decrease the quality of sleep especially in non-REM deep sleep. A dose of caffeine taken in the morning can have these effects the following night, so one of the main practices of sleep hygiene a person can do is to cease the consumption of caffeine.
Moderation
Keeping in mind that caffeine content in beverages and food varies and that some individuals are more sensitive to caffeine consumption than others are, moderation of caffeine is key. Between 200 and 300 mg of caffeine is considered "moderate" for most adults. While children can consume caffeine, it is advised to refrain children and adolescents from consuming caffeine due to their growing brains and to allow them to develop healthy sleep patterns.
Consequences of sleep disruption
Normal healthy sleep is described as having sufficient duration, quality, timing, regulation, and the absence of sleep disturbances or disorders. Even though the suggested amounts of sleep is relatively well known, there are increasing high numbers in the lack of healthy and good quality sleep.
Risk factors of sleep can range across many different arrays such as environmental, lifestyle, psychosocial, sleep disorders, or medical conditions. These are all circumstances which put individuals at risk for sleep disruption. Environmental risk factors for sleep disruption can include living in an area where there is excessive noise such as near an interstate, keeping an individual up later than normal. A lifestyle risk factor would include drinking alcohol, drug abuse, or a late shift at work. Psychosocial risk factors include being a caregiver for someone who needs constant attention, parents of young children, anxiety, worry, or stress, etc.
Sleep plays an essential part in brain functions and has crucial implications across almost all body systems. Numerous studies have shown caffeine consumption to heavily disrupt sleep patterns. This can lead to other implications such as lengthening the onset of sleep latency and decrease the efficiency and duration of sleep. Disruption of sleep also affects pressure for sleep and lowers electroencephalogram power in the frontal, central, and parietal regions of the brain. Short-term consequences of sleep disruption include: an increase in stress, emotional distress, mood and other mental health problems, cognition, memory, and performance deficits as well as an increase in behavioral problems in normally heathy individuals. Long-term consequences of sleep disruption include: cardiovascular problems such as cardiovascular disease, hypertension, higher concentration of fats in the body, weight issues such as metabolic syndrome, increased likelihood of cancer, and gastrointestinal disorders.
References
Further reading
External links
Caffeine
Sleep disorders | Caffeine-induced sleep disorder | [
"Biology"
] | 1,716 | [
"Behavior",
"Sleep",
"Sleep disorders"
] |
11,064,834 | https://en.wikipedia.org/wiki/Edward%20Adam | Edward Adam (11 October 1768 – 11 November 1807) was a French chemist who, beginning in 1800 while studying at Montpellier, invented various still modifications to improve chemical rectification, upon which the industrialization of the manufacture of products such as liquor have since been based.
References
1768 births
1807 deaths
19th-century French inventors
19th-century French chemists
University of Montpellier alumni
Scientists from Rouen
Distillation | Edward Adam | [
"Chemistry"
] | 83 | [
"Distillation",
"Separation processes"
] |
11,064,899 | https://en.wikipedia.org/wiki/Ballistic%20limit | The ballistic limit or limit velocity is the velocity required for a particular projectile to reliably (at least 50% of the time) penetrate a particular piece of material. In other words, a given projectile will generally not pierce a given target when the projectile velocity is lower than the ballistic limit. The term ballistic limit is used specifically in the context of armor; limit velocity is used in other contexts.
The ballistic limit equation for laminates, as derived by Reid and Wen is as follows:
where
is the ballistic limit
is a projectile constant determined experimentally
is the density of the laminate
is the static linear elastic compression limit
is the diameter of the projectile
is the thickness of the laminate
is the mass of the projectile
Additionally, the ballistic limit for small-caliber into homogeneous armor by TM5-855-1 is:
where
is the ballistic limit velocity in fps
is the caliber of the projectile, in inches
is the thickness of the homogeneous armor (valid from BHN 360 - 440) in inches
is the angle of obliquity
is the weight of the projectile, in lbs
References
Ballistics | Ballistic limit | [
"Physics"
] | 224 | [
"Ballistics",
"Classical mechanics stubs",
"Applied and interdisciplinary physics",
"Classical mechanics"
] |
11,065,056 | https://en.wikipedia.org/wiki/Multispectral%20Scanner | The Multispectral Scanner (MSS) is one of the Earth's observing sensors introduced in the Landsat program. A Multispectral Scanner was placed aboard each of the first five Landsat satellites.
The scanner was designed at Hughes Aerospace by Virginia Norwood. Her design called for a six band scanner, but the first one launched had only four bands. For her work on the design Norwood is called "The Mother of Landsat."
MSS Technical Specifications
Notes
External links
NASA Multispectral Scanner page
Satellite imaging sensors | Multispectral Scanner | [
"Astronomy"
] | 110 | [
"Astronomy stubs"
] |
11,065,481 | https://en.wikipedia.org/wiki/Fitzpatrick%20scale | The Fitzpatrick scale (also Fitzpatrick skin typing test; or Fitzpatrick phototyping scale) is a numerical classification schema for human skin color. It was developed in 1975 by American dermatologist Thomas B. Fitzpatrick as a way to estimate the response of different types of skin to ultraviolet (UV) light. It was initially developed on the basis of skin color to measure the correct dose of UVA for PUVA therapy, and when the initial testing based only on hair and eye color resulted in too high UVA doses for some, it was altered to be based on the patient's reports of how their skin responds to the sun; it was also extended to a wider range of skin types. The Fitzpatrick scale remains a recognized tool for dermatological research into human skin pigmentation.
The following table shows the six categories of the Fitzpatrick scale in relation to the 36 categories of the older von Luschan scale:
Emoji modifiers
The Fitzpatrick scale is also the basis of skin color in emoji, with five modifiers according to the Fitzpatrick scale (types and merged).
Eurocentric bias
The Fitzpatrick scale has been criticized for its Eurocentric bias and insufficient representation of global skin color diversity. The scale originally was developed for classifying "white skin" in response to solar radiation, and initially included only four categories focused on white skin, with "brown" and "black" skin types (V and VI) added as an afterthought.
The scale's methodology, relying on self-reporting of skin color, sunburn, and sun tanning response, fails to capture the broad spectrum of skin reflectance. Studies demonstrate that European populations have the narrowest skin color variation, whereas groups categorized as 'brown' or 'black' exhibit a much wider range.
The efficacy of the Fitzpatrick scale even among white-skinned individuals has been argued to be questionable, since studies such as that on a Dutch student population have found it inadequate for categorizing, challenging its appropriateness for investigating the relationship between sunburn tendency and tanning ability.
The Fitzpatrick scale's Eurocentric orientation and its limitations in accurately representing global skin color diversity, along with similar biases in classifying other phenotypic traits, have been argued to require more inclusive and scientifically valid categorizations in dermatological and genetic research.
See also
Monk Skin Tone Scale
von Luschan's chromatic scale
Skin reflectance
Brown Paper Bag Test
References
Dermatologic terminology
Human skin color
1975 introductions
Color scales | Fitzpatrick scale | [
"Biology"
] | 507 | [
"Human skin color",
"Pigmentation"
] |
11,065,526 | https://en.wikipedia.org/wiki/List%20of%20largest%20cities%20throughout%20history | This article lists the largest human settlements in the world (by population) over time, as estimated by historians, from 7000 BC when the largest human settlement was a proto-city in the ancient Near East with a population of about 1,000–2,000 people, to the year 2000 when the largest human settlement was Tokyo with 26 million.
Rome, Chang'an or Baghdad may have been the first city to have 1,000,000 people, as early as the 1st century or as late as the 8th century. Later cities that might have reached 1 million include Luoyang, Kaifeng, Hangzhou, Jinling, Beijing, and Edo. There is wide agreement that London was the first city to reach 2 million and New York was the first to reach 10 million.
The Greater Tokyo Area has been the most populous metropolitan area in the world since 1955, with more than 37.393 million residents as of 2020. Jakarta is expected to overtake Tokyo by 2030, partly due to Tokyo's shrinking population.
As disagreements between the sources show, any of the pre-19th century figures are uncertain, especially in ancient times. Estimating population sizes before censuses were conducted is a difficult task.
List of the most populous human settlements over time
The following table lists the most populous human settlements by estimated population at specified points in history according to three sources: Ian Morris, George Modelski and Tertius Chandler. City names are in bold where all three sources agree. It shows the evolution of the largest settlement from proto-city to city to urban area to metropolitan area.
See also
Historical urban community sizes, 7000 BC – 1875
List of largest European cities in history
List of largest cities, present day
Estimates of historical world population
Valeriepieris circle
References
External links
Top Ten Cities Through History, animation showing the ten largest cities throughout history according to Chandler
Top 20 Most Populated Cities in The World 1500 to 2100 (History + Projection)
Urban geography
Historical geography lists
Cities
Demographic history
Cities-related lists of superlatives
Cities
Largest things | List of largest cities throughout history | [
"Physics",
"Mathematics"
] | 412 | [
"Quantity",
"Largest things",
"Physical quantities",
"Size"
] |
11,065,783 | https://en.wikipedia.org/wiki/Manifold%20Destiny%20%28cookbook%29 | Manifold Destiny is a 1989 cookbook (), its updated 1998 edition () and a 2008 update () on the subject of cooking on the surface of a car engine. It was written by Chris Maynard and Bill Scheller, a photographer and a travel writer who were also rally drivers.
The authors claimed inspiration from a trip from Montreal to Boston, where the authors were inspired to keep a package of smoked meat from Schwartz's in Montreal hot by placing it in a secure spot on the car's engine block, having heard that it was said to be common for truckers to keep cans of soup hot by doing the same thing.
See also
Outdoor cooking
References
Cookbooks
1989 non-fiction books
Transport culture | Manifold Destiny (cookbook) | [
"Physics"
] | 145 | [
"Physical systems",
"Transport",
"Transport culture"
] |
11,066,006 | https://en.wikipedia.org/wiki/A%20Certain%20Magical%20Index | is a Japanese light novel series written by Kazuma Kamachi and illustrated by Kiyotaka Haimura, which has been published by ASCII Media Works under their Dengeki Bunko imprint since April 2004 in a total of three separate series. The first ran from April 2004 to October 2010, the second from March 2011 to July 2019, and the third from February 2020 to present.
The plot is set in a world where humans called espers possess supernatural abilities. The light novels focus on Toma Kamijo, a young high school student in Academy City with the ability to cancel other espers' powers, as he encounters an English nun named Index. His ability, which allows him to cancel other powers by touching them, and his relationship with Index prove dangerous to other sorcerers and espers who wanted to discover the secrets behind him and Index, as well as the city.
A manga adaptation by Chuya Kogino began serialization in Monthly Shōnen Gangan in April 2007. J.C.Staff produced two 24-episode anime series between 2008 and 2011. An animated film was released in February 2013. A 26-episode third season aired between 2018 and 2019. Several spin-offs and other adaptations have also been made, including several video games.
After being rejected for the Dengeki Novel Prize, Kamachi was contacted by Kazuma Miki, an editor at ASCII Media Works who had him write several test novels. He got the chance to write a full series and decided to create it with the concept of exploring the rules of magic, rather than just having it exist, and the inclusion of science to oppose its elements. The resulting series has seen success with both critics and audiences, with critics praising the action and characters.
Synopsis
Setting
A Certain Magical Index is set in a world where supernatural abilities are a reality. Individuals who possess special powers acquired via science are called . Those Espers who gain their abilities without the aid of special scientific instruments, whether at birth or otherwise, are referred to as . Others, known as , gain their powers upon mastering the power of magic, either from obtaining knowledge from different mythologies or by using mystical artifacts, although the existence of sorcerers is a secret to the public. While Sorcerers align themselves with different beliefs, Espers are aligned with scientific institutions. This leads to a power struggle between the magic and science factions for control of the world.
Plot
The story is set in , a technologically advanced independent city-state located in the west of Tokyo, Japan, which is known for its educational and research institutions. Toma Kamijo is a student in Academy City whose right hand's power called the Imagine Breaker could negate any supernatural powers but also his luck, much to his chagrin. One day, Toma meets a young English girl named Index, a nun from Necessarius, a secret magic branch of the Church of England, whose mind had been implanted with the Index Librorum Prohibitorum – 103,000 forbidden magical books the Church stored in secret locations. His encounter with her leads him to meet others from the secret worlds of science and magic. Toma's unusual power places him at the center of conflicts between the Sorcerers and Espers in Academy City who planned to unravel the secrets behind Academy City, Index, and Toma's special power.
Besides its manga adaptation, the series also has four spin-offs focusing on other characters. One of them is A Certain Scientific Railgun, which focuses on Mikoto Misaka, an Electromaster and the third most powerful Esper in Academy City. The second, A Certain Scientific Accelerator, focuses on Accelerator, a teenager capable of controlling vectors and the most powerful Esper in Academy City. The third, A Certain Scientific Dark Matter, deals with the second most powerful Esper in Academy City named Teitoku Kakine and his past. The fourth, A Certain Scientific Mental Out, follows the fifth Level 5 Esper and most powerful psychological psychic named Misaki Shokuhō in her election campaign for the next president of Tokiwadai Middle School's student body.
Development
Kazuma Kamachi started his work with A Certain Magical Index when he received a call from Kazuma Miki, the light novel editor, after his submission was rejected at the 9th Dengeki Game Novel Prize (now Dengeki Novel Prize) in 2002. Miki began to train him in writing multiple test novels, including a story about a girl sister and a boy with a mysterious arm which became the basis for his light novel.
In his essay titled "If It's Interesting Anything Goes: 600 Million Copies Printed—The Day in the Life of a Certain Editor", Miki stated that the light novel was originally called but he chose the current title because the word "Index" left a "strong personality in the sense and direction" upon his reading of the manuscript. Kamachi revealed that Index's name was derived from the kanji he found from looking in the encyclopedia since he wanted a name that would "stand out for the character the story was centered around". He avoided using difficult kanji for Toma Kamijo's name to help readers able to read it but he kept the meaning behind the character's epithet ("The One Who Purifies God and Slays Demons") a secret for now.
When it came the time to write the story, Kamachi investigated the terms "sorcerer" and "real" online for him to build the world of magic and the magicians' existence in his light novel. He also realized that most other Dengeki Bunko novels had magic as a main theme; however, none of them actually invested much into its inner-workings. As such, he decided to use this as the premise for the series. In setting up the world of science, Kamachi "needed some kind of power to oppose" the magic side. This helped him to create the idea of Toma Kamijo's known power, the Imagine Breaker, and set the stage for the world-building of Academy City "where science, espers, and magic would gather".
Upon the release of the first volume of the light novel, Miki stated that "(to be blunt) it sold like crazy. Shortly after the official release date, we had to do a reprint half the size of the original printing. It was on a Monday. I still remember it now. It was quite an achievement for an unknown newcomer". After the success of the first volume, the second volume was completed in 17 days. Subsequent volumes were also completed quickly, with the story for the ninth volume completed before the release of the fifth volume.
Media
Light novels
A Certain Magical Index is a light novel series written by Kamachi and illustrated by Kiyotaka Haimura. ASCII Media Works published 25 volumes between April 10, 2004, and August 10, 2011, under their Dengeki Bunko imprint; 22 comprise the main story while the other three are short story collections. On May 4, 2021, all volumes were free to read for one day in the Dengeki Novekomi app developed by Kadokawa Corporation. Yen Press licensed the series in North America in April 2014, which began releasing under their Yen On imprint in November, and its omnibus edition in November 2022.
A sequel series, titled , began publication on March 10, 2011 and concluded on July 10, 2019, with the publication of its 23rd volume. On May 4, 2021, they began to be published in the Dengeki Novekomi app. A third light novel series, titled , began publication on February 7, 2020. Yen Press has acquired New Testament for English publication.
Kamachi wrote short novels exclusively for Haimura's three artbook collections. The first short novel, titled A Certain Magical Index SS: Love Letter Competition, was included in the release of Kiyotaka Haimura Artbook rainbow spectrum:colors on February 28, 2011. The second short novel, titled New Testament: A Certain Magical Index SS, was included in the release of Kiyotaka Haimura Artbook 2 rainbow spectrum:notes on September 9, 2014. The third short novel, titled Genesis Testament: A Certain Magical Index SS, was included in the release of Kiyotaka Haimura Artbook 3 CROSS on May 9, 2020.
The bonus novels that Kamachi wrote for the series' Blu-ray/DVD releases are compiled into two volumes titled to commemorate the 15th anniversary of his debut, which were published on June 10 and August 7, 2020.
A spin-off novel series written by Kamachi and illustrated by Nilitsu focusing on the women belonging to Academy City's dark side, titled , was announced in January 2023. As of August 10, 2023, a total of two volumes have been released in Japan.
Manga
The series has been adapted into two manga series. The one based on the novels is illustrated by Chuya Kogino and started serialization in the May 2007 issue of Square Enix's Monthly Shōnen Gangan. The first tankōbon volume was released in Japan on November 10, 2007. As of November 12, 2024, 31 volumes have been published. Yen Press has licensed the series in North America and has been publishing the manga since May 19, 2015. The manga is also licensed in Italy by Star Comics.
The other manga adaptation based on A Certain Magical Index: The Movie – The Miracle of Endymion is illustrated by Ryōsuke Asakura and was serialized from February 12 to October 12, 2013. Square Enix published the first volume on August 27 and the second volume on October 22.
Spin-offs
A side-story manga series illustrated by Motoi Fuyukawa, titled A Certain Scientific Railgun, started serialization in the April 2007 issue of Dengeki Daioh. As of March 2023, 18 volumes have been released. Its spin-off, titled A Certain Scientific Railgun: Astral Buddy, was serialized in Dengeki Daioh from April 27, 2017, to July 27, 2020. It was published in four volumes. A second side-story manga series illustrated by Arata Yamaji, titled A Certain Scientific Accelerator, was serialized in Dengeki Daioh from December 27, 2013, to July 27, 2020. It was published in twelve volumes. A third side-story manga series illustrated by Nankyoku Kisaragi, titled , was serialized in ASCII Media Works magazine Dengeki Daioh from August 27, 2019, to March 26, 2020 (the same day the compiled volume was published). A fourth side-story manga series illustrated by Yasuhito Nogi, titled , began serialization in Comic Newtype website on July 27, 2021. As of January 10, 2024, three volumes have been published.
A yonkoma manga spin-off illustrated by Mijin Kouka, titled , was serialized in Square Enix's Monthly Shōnen Gangan magazine from September 12, 2013, to May 12, 2016. A total of five tankōbon volumes had been published in Japan from February 22, 2014, to May 21, 2016. In March 2023, Kamachi revealed the manga adaptation of A Certain ITEM of Dark Side by Strelka which is serialized in Dengeki Daioh magazine starting October 26 of that year.
Anime
A 24-episode anime adaptation of A Certain Magical Index was produced by J.C.Staff and directed by Hiroshi Nishikiori, which was aired in Japan from October 4, 2008, to March 19, 2009. The anime was collected into eight Blu-ray and DVD sets, which were released from January 23 to August 21, 2009.
A second season titled A Certain Magical Index II began airing in Japan from October 8, 2010, to April 1, 2011 and was also streamed on Nico Nico Douga. The second season's eight volumes of Blu-ray/DVD sets were released from January 26 to September 22, 2011.
An animated film titled was released in Japan on February 23, 2013. It is based on an original story written by Kamachi and features the main characters from both Index and Railgun anime series, along with the new ones designed by Haimura. The Blu-ray/DVD set of the film, which was released on August 28, is included with a bonus anime titled A Certain Magical Index-tan: The Movie – The Miracle of Endymion... Happened, or Maybe Not.
The 26-episode third season titled A Certain Magical Index III aired in Japan from October 5, 2018, to April 5, 2019. The third season's eight volumes of Blu-ray/DVD sets were released from December 26, 2018 to July 31, 2019, with episodes 6 and 7 of the bonus short anime parody titled A Certain Magical Index-tan, which depicted Index in her chibi form, included in the first and fifth limited edition releases. The third season was originally planned to be a reboot but it was later decided to be a sequel instead. The three seasons were released on Hulu in Japan on March 24, 2022.
In North America, Funimation (which now goes by the name of Crunchyroll LLC) has licensed the series for home video and streaming. An English language dub began streaming on their website in September 2012 and was released on DVD on December 11. The first season aired in North America on the Funimation Channel on January 21, 2013. It can also been seen on the Crunchyroll streaming service after the Funimation brand was unified with the former in 2022.
The series was released in Australia by a partnership between Universal Pictures Home Entertainment and Sony Pictures. Funimation has also licensed the film in North America and released it at theaters in the United States on January 12, 2015. Animatsu Entertainment released the series in the United Kingdom. In Southeast Asia, Muse Communication licensed the series and broadcast it through i-Fun Anime Channel and their YouTube channel.
Music
Maiko Iuchi of I've Sound is in charge of music for the series' three seasons. The first opening theme music, used in episodes 1–16 of the first season of A Certain Magical Index, is "PSI-Missing", while the second one, used in episode 17 onwards, is "Masterpiece", both performed by Mami Kawada. The first ending theme music, used in episodes 1–19, is , while the second one, used in episode 20 onwards, is , both performed by Iku.
The first opening theme music of A Certain Magical Index II is "No Buts!", while the second one, introduced in episode 17, is "See Visions", both performed by Kawada. The first ending theme music, used in episodes 1–13, is "Magic∞World", while the second one, used in episode 14 onwards, is , both performed by Kurosaki.
The ending theme music of A Certain Magical Index: The Movie – The Miracle of Endymion is "Fixed Star" by Kawada and the single was released on February 20, 2013. The first opening theme music of A Certain Magical Index III is "Gravitation", while the second one is "Roar", both performed by Kurosaki. The first ending theme music is , while the second one is , both performed by Yuka Iguchi.
Video games
A 3D fighting game titled A Certain Magical Index was developed by Shade for the PlayStation Portable (PSP) and published by ASCII Media Works on January 27, 2011. Heroz developed a social card game for Mobage titled A Certain Magical Index: Struggle Battle, which was published by ASCII Media Works on December 25, 2012. The game was updated to A Certain Magical Index: Struggle Battle II, but was later announced at the end of its service on March 30, 2018.
Guyzware and Namco Bandai Games announced on June 8, 2012, a collaboration project for a game adaptation of the series, which was revealed to be a crossover visual novel game for PSP between A Certain Magical Index and A Certain Scientific Railgun franchises titled A Certain Magical and Scientific Ensemble. The game was released on February 21, 2013. Heroz also developed an action puzzle game titled A Certain Magical and Scientific Puzzdex, which was published by ASCII Media Works in 2014. NetEase Games developed a massively multiplayer online role-playing game based on the series with supervision from Kadokawa Corporation, titled A Certain Magical Index: Genuine Mobile Game, which was released to the Chinese market in 2017.
On January 4, 2019, Square Enix released a teaser trailer that announced their game titled A Certain Magical Index: Imaginary Fest, which was released on July 4. Fuji Shoji, a Japanese company known for their pachinko and pachislot products, released a teaser trailer on August 24, 2020, for the series' pachinko, which was later launched in November. Sun Electronics adapted it into a mobile game and launched it on December 17, 2020.
Other media
A radio drama was broadcast in Dengeki Taishō, narrating the story of an encounter with the mysterious self-proclaimed "former" sorcerer by Toma Kamijo and Index in a family restaurant after Mikoto Misaka decided to go back due to urgent business. It was later released as a drama CD, which was included in the mail-in order of the 48th volume of Dengeki hp. The drama CD, which contains a new story about Misaka and Kuroko Shirai with their "urgent business" and a duel request by a Level 3 psychic girl from Tokiwadai Middle School, became available for purchase in December 2007.
Geneon Universal Entertainment (now NBCUniversal Entertainment Japan) released four audio dramas for the first season of Index under the title A Certain Magical Index Archives from March 25 to August 21, 2009. The same enterprise released another four audio dramas for the second season from May 25 to August 24, 2011. A drama CD for A Certain Magical Index III was released as a bonus for customers who purchased the limited edition volume sets of the series via Amazon'''s Japanese website.
Several characters from A Certain Magical Index cross over with other characters created by Kamachi in his light novel , which was published on February 10, 2015. As a collaboration with Sega's Virtual On video game franchise, Kamachi wrote the crossover light novel titled with mecha illustrations designed by Hajime Katoki, which was released on May 10, 2016. One of Kamachi's light novel works, , crosses over with A Certain Magical Index under the title , which was released in May 2020.
A manga adaptation of The Circumstance Leading to a Simple Killer Princess' Marriage Was a Certain Magical Heavy Zashiki Warashi was serialized on Monthly Shōnen Gangan from February 12 to October 10, 2015. The first tankōbon volume was published on November 21, 2015, and the final volume on December 22. A manga adaptation of A Certain Magical Virtual-On began publication in ASCII Media Works' Monthly Denplay Comic magazine from March 10, 2018, to June 26, 2019, with a total of three tankōbon volumes.
The series is featured in Dengeki Gakuen RPG: Cross of Venus for the Nintendo DS, with Index appearing as a supporting character. The series was also adapted into Bushiroad's Weiß Schwarz collectible card game, which was released on April 24, 2010. Index also makes a cameo appearance in the Oreimo PSP game. Sega's Dengeki Bunko: Fighting Climax brings Mikoto Misaka as a playable character, while Toma Kamijo and Accelerator are assist characters. Sega and Dengeki Bunko later collaborated to develop A Certain Magical Virtual-On for the PlayStation 4 and PlayStation Vita, which was released on February 15, 2018. Toma, Mikoto, Accelerator, Kuroko Shirai, and Kazari Uiharu appear as playable characters in Dengeki Bunko: Crossing Void, a 2018 mobile game developed by 91Act and Sega.
Reception
Awards
The light novel series has consistently ranked in the top ten light novels in Takarajimasha's guidebook Kono Light Novel ga Sugoi!. Notably, the series ranked first in 2011, while also ranking in the top three in 2012, 2013, 2014, and 2017. In 2020, the series was inducted into the hall of fame, thus barred from ranking in future years. Kamachi, Haimura, and several of the series' characters have also ranked in the guidebook, notably with Mikoto Misaka winning the award for best female character nine times in ten years.
In Kadokawa Shoten's Light Novel Award contest held in 2007, A Certain Magical Index was a runner-up in the action category. The series also ranked in Kadokawa Light Novel Expo 2020's top light novels in the infinite passion category.
Sales
In May 2010, it was reported that A Certain Magical Index became Dengeki Bunko's number one bestseller and it became the first Dengeki Bunko series to sell over 10 million copies. Later that year, it became the fifth best-selling light novel in Japan, beating other popular series such as Full Metal Panic! and Haruhi Suzumiya. It was reported in October 2014 that the entire franchise, including the light novels and manga, had sold over 28 million copies. It was reported in August 2017 that the light novels have sold over 16.35 million copies. In July 2018, the series was reported to have sold over 30 million copies. It was reported with the release of Sorcery Hacker >> Divulge the Magic Vulnerability that the physical sales of the series had reached 18 million copies. As of May 2021, it was reported that the light novel, manga, and spin-off series reached 31 million copies.
Critical reception
Matthew Warner from The Fandom Post rated the first volume of the light novel an 'A', calling it a "fantastic start". Sean Gaffney from A Case Suitable for Treatment also praised it, calling it a "solid beginning", while also noted that it can be a bit slow at times. Theron Martin from Anime News Network also praised it for the concept, as well as for keeping Toma Kamijo balanced, while also criticizing the illustrations.
Richard Gutierrez from The Fandom Post praised the premise of the manga, but criticized the execution due to the lack of background it provides. Leroy Douresseaux from Comic Book Bin praised the volume he reviewed, stating the art by Chuya Kogino fits the series perfectly. However, Erkael from Manga News was more critical, specifically for the artwork, but he did praise the story and concept.
Chris Beveridge from The Fandom Post praised the anime adaptation, calling it a "fun series" and "pretty engaging". Ian Wolf from Anime UK News also praised the series, specifically for the action, while calling the music "[just] okay". Like Beveridge and Wolf, Carl Kimlinger from Anime News Network also offered praise to the series for the characters and action, while criticizing for being a bit generic at times. Like Kimlinger, Theron Martin from the same website also praised the action and characters, while criticizing it for feeling preachy at times. André Van Renssen from Active Anime called the series "a decent show", comparing it to Shakugan no Shana'' for its action. Despite that, they also criticized the series for being too violent at times.
Notes
References
External links
2004 Japanese novels
2007 manga
2008 anime television series debuts
2011 Japanese novels
2016 Japanese novels
Action anime and manga
ASCII Media Works manga
Book series introduced in 2004
Dengeki Bunko
Dengeki Daioh
AT-X (TV network) original programming
Fiction books about psychic powers
Funimation
Gangan Comics manga
Fiction about genetic engineering
J.C.Staff
Kadokawa Dwango franchises
Light novels
Muse Communication
NBCUniversal Entertainment Japan
Anime and manga set in schools
Science fantasy anime and manga
Shōnen manga
Square Enix franchises
Television shows based on light novels
Warner Entertainment Japan franchises
Works published under a pseudonym
Yen Press titles | A Certain Magical Index | [
"Engineering",
"Biology"
] | 4,922 | [
"Genetic engineering",
"Fiction about genetic engineering"
] |
11,066,141 | https://en.wikipedia.org/wiki/Acronis%20Secure%20Zone | Acronis Secure Zone is a hard disk partition type created and used by Acronis True Image as a backup storage target.
Overview
Backup applications typically use network storage for storing backup archives, but this can be problematic when such resources are not available. Acronis designed a solution to this problem by carving off part of the local disk as a proprietary partition, which they refer to as Acronis Secure Zone. Since this partition is accessibly only by True Image and Backup & Recovery, it functions as a backup target safe from malware, user files, or other uses or corruption. Acronis True Image can manage only one Acronis Secure Zone per computer but can restore data off others (e.g., when a portable hard drive is connected).
Technical Details
Although the Acronis Secure Zone has its own partition type, it is actually just a rebadged FAT32 partition labeled ACRONIS SZ, with "partition type" code set to . Knowing these requirements, one can manually create and/or manage existing Acronis Secure Zone using any partition manager. Since the Acronis Secure Zone is just a modified FAT32 partition type, it is possible to gain direct access to this partition by changing its partition type code to (FAT32 LBA).
Acronis True Image is designed to self-manage the backup archives stored to the Acronis Secure Zone. As such, all backup files are stored with autogenerated names in the root folder. If there is not enough free space for the next backup file, Acronis True Image will delete the oldest image set (base+incremental/differential files) in order to create space for the new files.
Original Equipment Manufacturer Secure Zone
OEM versions of True Image are designed to use a special "Original Equipment Manufacturer secure zone", which is technically the same as a regular Acronis Secure Zone, but uses a partition type of 0xBB, and typically contains only a single image file with the "factory default" operating system and application configuration set forth by the manufacturer.
References
Computer storage devices
Disk file systems | Acronis Secure Zone | [
"Technology"
] | 429 | [
"Computer storage devices",
"Recording devices"
] |
11,066,595 | https://en.wikipedia.org/wiki/Douglas%20A.%20Melton | Douglas A. Melton is an American medical researcher who is the Xander University Professor at Harvard University, and was an investigator at the Howard Hughes Medical Institute until 2022. Melton serves as the co-director of the Harvard Stem Cell Institute and was the first co-chairman (with David Scadden) of the Harvard University Department of Stem Cell and Regenerative Biology. Melton is the founder of several biotech companies including Gilead Sciences, Ontogeny (now Curis), iPierian (now True North Therapeutics ), and Semma Therapeutics. Melton holds membership in the National Academy of the Sciences, the American Academy of Arts and Sciences, and is a founding member of the International Society for Stem Cell Research.
Early life and education
Melton grew up in Blue Island, Illinois and completed a Bachelor of Science degree in biology at the University of Illinois at Urbana–Champaign in 1975. He was awarded a Marshall Scholarship for study at the University of Cambridge where he received a Bachelor of Arts degree in the history and philosophy of science in 1977 and a PhD under the supervision of John Gurdon.
Career and research
Melton's early work was in general developmental biology, identifying genes important for cell fate determination and body pattern. This led to the finding that the nervous system in vertebrates is formed as a default when early embryonic cells do not receive inductive signals to become mesoderm or endoderm. He also pioneered the technique of in vitro transcription with bacterial SP6 RNA polymerase. This RNA transcription system is now widely used to make large amounts of messenger RNAs in vitro and is, for example, the basis for production of the COVID mRNA vaccines.
In the mid-1990s, work in his lab became centered on the development of the pancreas aiming to find new treatments for diabetes.
In 2001 when President George W. Bush cut federal funding of embryonic stem cell research, Melton used private donations to create 17 published human stem cell lines and distributed them without charge to researchers around the world.
In August 2008, Melton's lab published successful in vivo reprogramming of adult mice exocrine pancreatic cells into insulin secreting cells which closely resembled endogenous islet beta cells of the pancreas in terms of their size, shape, ultrastructure, and essential marker genes. Unlike producing beta cells from conventional embryonic stem cells or the more recently developed induced pluripotent stem cell (iPSC) technique, Melton's method involved direct cell reprogramming of an adult cell type (exocrine cell) into other adult cell type (beta cell) without reversion to a pluripotent stem cell state.
His current research interests include pancreatic developmental biology and the directed differentiation of human embryonic stem cells, particularly in pertinence to type 1 diabetes. In 2014, he reported a method using human pluripotent stem cells to generate virtually unlimited quantities of functional insulin-producing beta cells that respond appropriately to a glucose challenge. This is considered a significant step forward in regenerative medicine for the possible treatment of diabetes, including type I diabetes, which afflicts both his children.
In 2022, Melton left Harvard University and joined Vertex Pharmaceuticals full-time to create diabetes treatments.
Awards and honors
Melton was elected a member of the National Academy of Sciences and the American Academy of Arts and Sciences in 1995. In 2007 and again in 2009, Melton was listed among the Time 100 Most Influential People in the World. In 2016, Melton was awarded the Ogawa-Yamanaka Prize in Stem Cell Biology. In 2023 he received the Abarca Prize for his advances towards a cure for diabetes.
References
External links
1953 births
Living people
American medical researchers
University of Illinois Urbana-Champaign alumni
Richard-Lounsbery Award laureates
Harvard University faculty
Marshall Scholars
Members of the United States National Academy of Sciences
Howard Hughes Medical Investigators
Stem cell researchers
People from Blue Island, Illinois
Members of the National Academy of Medicine
Searle Scholars Program recipients | Douglas A. Melton | [
"Biology"
] | 824 | [
"Stem cell researchers",
"Stem cell research"
] |
11,066,704 | https://en.wikipedia.org/wiki/Electricity%20Directive%202019 | The Electricity Directive 2019 (2019/944) is a Directive in EU law concerning rules for the internal market in electricity.
Background
The first Electricity Directive 96/92/EC on common rules for the internal market in electricity aimed to create an internal market for electricity. Concrete provisions were thought to be needed to ensure a level playing field in generation and to reduce the risks of market dominance and predatory behaviour, ensuring non-discriminatory transmission and distribution tariffs, through access to the network based on third-party access rights and on the basis of tariffs published prior to their entry into force, and ensuring that the rights of small and vulnerable customers are protected and that information on energy sources for electricity generation is disclosed, as well as reference to sources, where available, giving information on their environmental impact.
To ensure efficient and non-discriminatory network access, the updated Directive sought to ensure distribution and transmission systems are operated through legally separate entities where vertically integrated undertakings exist. Independent management structures had to be in place between the distribution system operators, the transmission system operators, and any generation/supply companies. Legal separation does not imply a change of ownership of assets and nothing prevents similar or identical employment conditions applying throughout the whole of the vertically integrated undertakings. However, a non-discriminatory decision-making process should be ensured through organisational measures regarding the independence of the decision-makers responsible.
The 1996 Directive was updated and replaced by the Electricity Directive 2003/54/EC, followed by Directive 2009/72/EC, and then the current Electricity Directive 2019/944.
Contents
Articles 3 to 6 require that different enterprises have rights to access infrastructure of network owners on fair and transparent terms, as a way to ensure different member state networks and supplies can become integrated across the EU.
Article 8 requires that electricity or gas enterprises acquire a licence from member state authorities
Article 35 requires that there is legal separation into different entities of owners of networks from retailers, although they can be owned by the same enterprise, to ensure transparency of accounting.
See also
EU law
Energy policy of the European Union
References
External links
Directive (EU) 2019/944 of 5 June 2019 on common rules for the internal market for electricity on EUR-Lex
EU legislation summary
Electricity in the European Union.
Energy economics
Electric power in the European Union
European Union energy law
Energy policies and initiatives of the European Union
Economy of the European Union
Politics of the European Union
European Union directives
2003 in law
2003 in the European Union | Electricity Directive 2019 | [
"Environmental_science"
] | 497 | [
"Energy economics",
"Environmental social science"
] |
11,066,871 | https://en.wikipedia.org/wiki/Font%20editor | A font editor is a class of application software specifically designed to create or modify font files. Font editors differ greatly depending on if they are designed to edit bitmap fonts or outline fonts. Most modern font editors deal with the outline fonts. Bitmap fonts uses an older technology and are most commonly used in console applications. The bitmap font editors were usually very specialized, as each computing platform had its own font format. One subcategory of bitmap fonts is text mode fonts.
List of font editors
The following editors use outline vector graphics to create font files in common formats.
Website
FontStruct
Free software
Birdfont
FontForge
Inkscape
Proprietary software
FontLab (Mac, Windows)
Fontographer (Mac, Windows)
Ikarus
Glyphs
See also
Typography
Comparison of font editors
References
Editor
Digital typography | Font editor | [
"Technology"
] | 180 | [
"Computing stubs",
"Digital typography stubs"
] |
11,067,444 | https://en.wikipedia.org/wiki/Darboux%20frame | In the differential geometry of surfaces, a Darboux frame is a natural moving frame constructed on a surface. It is the analog of the Frenet–Serret frame as applied to surface geometry. A Darboux frame exists at any non-umbilic point of a surface embedded in Euclidean space. It is named after French mathematician Jean Gaston Darboux.
Darboux frame of an embedded curve
Let S be an oriented surface in three-dimensional Euclidean space E3. The construction of Darboux frames on S first considers frames moving along a curve in S, and then specializes when the curves move in the direction of the principal curvatures.
Definition
At each point of an oriented surface, one may attach a unit normal vector in a unique way, as soon as an orientation has been chosen for the normal at any particular fixed point. If is a curve in , parametrized by arc length, then the Darboux frame of is defined by
(the unit tangent)
(the unit normal)
(the tangent normal)
The triple defines a positively oriented orthonormal basis attached to each point of the curve: a natural moving frame along the embedded curve.
Geodesic curvature, normal curvature, and relative torsion
Note that a Darboux frame for a curve does not yield a natural moving frame on the surface, since it still depends on an initial choice of tangent vector. To obtain a moving frame on the surface, we first compare the Darboux frame of γ with its Frenet–Serret frame. Let
(the unit tangent, as above)
(the Frenet normal vector)
(the Frenet binormal vector).
Since the tangent vectors are the same in both cases, there is a unique angle α such that a rotation in the plane of N and B produces the pair t and u:
Taking a differential, and applying the Frenet–Serret formulas yields
where:
κg is the geodesic curvature of the curve,
κn is the normal curvature of the curve, and
τr is the relative torsion (also called geodesic torsion) of the curve.
Darboux frame on a surface
This section specializes the case of the Darboux frame on a curve to the case when the curve is a principal curve of the surface (a line of curvature). In that case, since the principal curves are canonically associated to a surface at all non-umbilic points, the Darboux frame is a canonical moving frame.
The trihedron
The introduction of the trihedron (or trièdre), an invention of Darboux, allows for a conceptual simplification of the problem of moving frames on curves and surfaces by treating the coordinates of the point on the curve and the frame vectors in a uniform manner. A trihedron consists of a point P in Euclidean space, and three orthonormal vectors e1, e2, and e3 based at the point P. A moving trihedron is a trihedron whose components depend on one or more parameters. For example, a trihedron moves along a curve if the point P depends on a single parameter s, and P(s) traces out the curve. Similarly, if P(s,t) depends on a pair of parameters, then this traces out a surface.
A trihedron is said to be adapted to a surface if P always lies on the surface and e3 is the oriented unit normal to the surface at P. In the case of the Darboux frame along an embedded curve, the quadruple
(P(s) = γ(s), e1(s) = T(s), e2(s) = t(s), e3(s) = u(s))
defines a tetrahedron adapted to the surface into which the curve is embedded.
In terms of this trihedron, the structural equations read
Change of frame
Suppose that any other adapted trihedron
(P, e1, e2, e3)
is given for the embedded curve. Since, by definition, P remains the same point on the curve as for the Darboux trihedron, and e3 = u is the unit normal, this new trihedron is related to the Darboux trihedron by a rotation of the form
where θ = θ(s) is a function of s. Taking a differential and applying the Darboux equation yields
where the (ωi,ωij) are functions of s, satisfying
Structure equations
The Poincaré lemma, applied to each double differential ddP, ddei, yields the following Cartan structure equations. From ddP = 0,
From ddei = 0,
The latter are the Gauss–Codazzi equations for the surface, expressed in the language of differential forms.
Principal curves
Consider the second fundamental form of S. This is the symmetric 2-form on S given by
By the spectral theorem, there is some choice of frame (ei) in which (iiij) is a diagonal matrix. The eigenvalues are the principal curvatures of the surface. A diagonalizing frame a1, a2, a3 consists of the normal vector a3, and two principal directions a1 and a2. This is called a Darboux frame on the surface. The frame is canonically defined (by an ordering on the eigenvalues, for instance) away from the umbilics of the surface.
Moving frames
The Darboux frame is an example of a natural moving frame defined on a surface. With slight modifications, the notion of a moving frame can be generalized to a hypersurface in an n-dimensional Euclidean space, or indeed any embedded submanifold. This generalization is among the many contributions of Élie Cartan to the method of moving frames.
Frames on Euclidean space
A (Euclidean) frame on the Euclidean space En is a higher-dimensional analog of the trihedron. It is defined to be an (n + 1)-tuple of vectors drawn from En, (v; f1, ..., fn), where:
v is a choice of origin of En, and
(f1, ..., fn) is an orthonormal basis of the vector space based at v.
Let F(n) be the ensemble of all Euclidean frames. The Euclidean group acts on F(n) as follows. Let φ ∈ Euc(n) be an element of the Euclidean group decomposing as
where A is an orthogonal transformation and x0 is a translation. Then, on a frame,
Geometrically, the affine group moves the origin in the usual way, and it acts via a rotation on the orthogonal basis vectors since these are "attached" to the particular choice of origin. This is an effective and transitive group action, so F(n) is a principal homogeneous space of Euc(n).
Structure equations
Define the following system of functions F(n) → En:
The projection operator P is of special significance. The inverse image of a point P−1(v) consists of all orthonormal bases with basepoint at v. In particular, P : F(n) → En presents F(n) as a principal bundle whose structure group is the orthogonal group O(n). (In fact this principal bundle is just the tautological bundle of the homogeneous space F(n) → F(n)/O(n) = En.)
The exterior derivative of P (regarded as a vector-valued differential form) decomposes uniquely as
for some system of scalar valued one-forms ωi. Similarly, there is an n × n matrix of one-forms (ωij) such that
Since the ei are orthonormal under the inner product of Euclidean space, the matrix of 1-forms ωij is skew-symmetric. In particular it is determined uniquely by its upper-triangular part (ωji | i < j). The system of n(n + 1)/2 one-forms (ωi, ωji (i<j)) gives an absolute parallelism of F(n), since the coordinate differentials can each be expressed in terms of them. Under the action of the Euclidean group, these forms transform as follows. Let φ be the Euclidean transformation consisting of a translation vi and rotation matrix (Aji). Then the following are readily checked by the invariance of the exterior derivative under pullback:
Furthermore, by the Poincaré lemma, one has the following structure equations
Adapted frames and the Gauss–Codazzi equations
Let φ : M → En be an embedding of a p-dimensional smooth manifold into a Euclidean space. The space of adapted frames on M, denoted here by Fφ(M) is the collection of tuples (x; f1,...,fn) where x ∈ M, and the fi form an orthonormal basis of En such that f1,...,fp are tangent to φ(M) at φ(x).
Several examples of adapted frames have already been considered. The first vector T of the Frenet–Serret frame (T, N, B) is tangent to a curve, and all three vectors are mutually orthonormal. Similarly, the Darboux frame on a surface is an orthonormal frame whose first two vectors are tangent to the surface. Adapted frames are useful because the invariant forms (ωi,ωji) pullback along φ, and the structural equations are preserved under this pullback. Consequently, the resulting system of forms yields structural information about how M is situated inside Euclidean space. In the case of the Frenet–Serret frame, the structural equations are precisely the Frenet–Serret formulas, and these serve to classify curves completely up to Euclidean motions. The general case is analogous: the structural equations for an adapted system of frames classifies arbitrary embedded submanifolds up to a Euclidean motion.
In detail, the projection π : F(M) → M given by π(x; fi) = x gives F(M) the structure of a principal bundle on M (the structure group for the bundle is O(p) × O(n − p).) This principal bundle embeds into the bundle of Euclidean frames F(n) by φ(v;fi) := (φ(v);fi) ∈ F(n). Hence it is possible to define the pullbacks of the invariant forms from F(n):
Since the exterior derivative is equivariant under pullbacks, the following structural equations hold
Furthermore, because some of the frame vectors f1...fp are tangent to M while the others are normal, the structure equations naturally split into their tangential and normal contributions. Let the lowercase Latin indices a,b,c range from 1 to p (i.e., the tangential indices) and the Greek indices μ, γ range from p+1 to n (i.e., the normal indices). The first observation is that
since these forms generate the submanifold φ(M) (in the sense of the Frobenius integration theorem.)
The first set of structural equations now becomes
Of these, the latter implies by Cartan's lemma that
where sμab is symmetric on a and b (the second fundamental forms of φ(M)). Hence, equations (1) are the Gauss formulas (see Gauss–Codazzi equations). In particular, θba is the connection form for the Levi-Civita connection on M.
The second structural equations also split into the following
The first equation is the Gauss equation which expresses the curvature form Ω of M in terms of the second fundamental form. The second is the Codazzi–Mainardi equation which expresses the covariant derivatives of the second fundamental form in terms of the normal connection. The third is the Ricci equation.
See also
Darboux derivative
Maurer–Cartan form
Notes
References
Differential geometry
Differential geometry of surfaces
Curvature (mathematics) | Darboux frame | [
"Physics"
] | 2,486 | [
"Geometric measurement",
"Physical quantities",
"Curvature (mathematics)"
] |
11,067,743 | https://en.wikipedia.org/wiki/Journal%20of%20Computational%20Chemistry | The Journal of Computational Chemistry is a peer-reviewed scientific journal published since 1980 by John Wiley & Sons. It covers research, contemporary developments in theory and methodology, and applications in all areas of computational chemistry, including ab initio quantum chemistry methods and semiempirical methods, density functional theory, molecular mechanics, molecular dynamics, statistical mechanics, cheminformatics, biomolecular structure prediction, molecular design, and bioinformatics.
According to the Journal Citation Reports, the journal has a 2020 impact factor of 3.376, ranking it 80th out of 179 journals in the category "Chemistry, Multidisciplinary".
References
External links
Chemistry journals
Academic journals established in 1980
Wiley (publisher) academic journals
English-language journals
Computational chemistry | Journal of Computational Chemistry | [
"Chemistry"
] | 156 | [
"Theoretical chemistry stubs",
"Theoretical chemistry",
"Computational chemistry",
"Computational chemistry stubs",
"Physical chemistry stubs"
] |
11,068,261 | https://en.wikipedia.org/wiki/Operating%20reserve | In electricity networks, the operating reserve is the generating capacity available to the system operator within a short interval of time to meet demand in case a generator goes down or there is another disruption to the supply. Most power systems are designed so that, under normal conditions, the operating reserve is always at least the capacity of the largest supplier plus a fraction of the peak load.
Types of operating reserve
The operating reserve is made up of the spinning reserve as well as the non-spinning or supplemental reserve:
The spinning reserve is the extra generating capacity that is available by increasing the power output of generators that are already connected to the power system. For most generators, this increase in power output is achieved by increasing the torque applied to the turbine's rotor.
The non-spinning reserve or supplemental reserve is the extra generating capacity that is not currently connected to the system but can be brought online after a short delay. In isolated power systems, this typically equates to the power available from fast-start generators. However, in interconnected power systems, this may include the power available on short notice by importing power from other systems or retracting power that is currently being exported to other systems.
Generators that intend to provide either spinning and non-spinning reserve should be able to reach their promised capacity within roughly ten minutes. Most power system guidelines require a significant fraction of their operating reserve to come from spinning reserve. This is because the spinning reserve is slightly more reliable (it doesn't suffer from start-up issues) and can respond immediately whereas with non-spinning reserve generators there is a delay as the generator starts-up offline.
Centrally controlled air conditioners and thermostats that are used in large residential areas can be used as a fast and considerable curtailment reserve. Advantages of this technology are under studies.
Operating reserve is a crucial concept for ensuring that the day-ahead planning of generators' schedule can withstand the uncertainty due to unforeseen variations in the load profile or equipment (generators, transformers, transmission links) faults.
The California Independent System Operator has an operating reserve at 6% of the metered load. Included in that is a spinning reserve at 3% of the metered load.
Other types of reserve
In addition, there are two other kinds of reserve power that are often discussed in combination with the operating reserve: the frequency-response reserve and the replacement reserve.
The frequency-response reserve (also known as regulating reserve) is provided as an automatic reaction to a loss in supply. It occurs because immediately following a loss of supply, the generators slow down due to the increased load. To combat this slowing, many generators have a governor. By helping the generators to speed up, these governors provide a small boost to both the output frequency and the power of each generator. However, because the frequency-response reserve is often small and not at the discretion of the system operator it is not considered part of the operating reserve.
The replacement reserve (also known as contingency reserve) is reserve power provided by generators that require a longer start-up time (typically thirty to sixty minutes). It is used to relieve the generators providing the spinning or non-spinning reserve and thus restore the operating reserve (confusingly the replacement reserve is sometimes known as the 30 or 60-minute operating reserve).
References
Power engineering | Operating reserve | [
"Engineering"
] | 670 | [
"Power engineering",
"Electrical engineering",
"Energy engineering"
] |
11,068,871 | https://en.wikipedia.org/wiki/Cercospora%20brassicicola | Cercospora brassicicola is a plant pathogen.
References
brassicicola
Fungal plant pathogens and diseases
Fungus species | Cercospora brassicicola | [
"Biology"
] | 26 | [
"Fungi",
"Fungus species"
] |
11,068,873 | https://en.wikipedia.org/wiki/Pseudocercosporella%20capsellae | Pseudocercosporella capsellae is a plant pathogen infecting crucifers (canola, mustard, rapeseed). P. capsellae is the causal pathogen of white leaf spot disease, which is an economically significant disease in global agriculture. P. capsellae has a significant effect on crop yields on agricultural products, such as canola seed and rapeseed. Researchers are working hard to find effective methods of controlling this plant pathogen, using cultural control, genetic resistance, and chemical control practices. Due to its rapidly changing genome, P. capsellae is a rapidly emerging plant pathogen that is beginning to spread globally and affect farmers around the world.
Habitat and Geographical Distribution
Habitat
Pseudocercosporella capsellae is generally found in humid environments. When P. capsellae is found in environments with low humidity, the fungus is unable to germinate and cause disease. This pathogen is not a thermophile, explaining how it is found in temperate climates without extreme heat. After introduction into an area, P. capsellae is found in most neighboring Brassicaceae agricultural fields. In the wild, P. capsellae can be observed in prairie environments containing mustard weed.
Geographical Distribution
P. capsellae has been identified on four of the seven continents of the world: North America, Europe, Asia, and Australia. Specifically, P. capsellae has been found in agricultural fields in China, Japan, Canada, India, Australia, the Pacific Northwest region of the United States, the United Kingdom, France, Poland, and Scandinavian nations.
Morphology and Microscopic Features
P. capsellae is an ascomycete, meaning it produces ascospores housed in asci as means of sexual reproduction. Sexual structures are found in the sexual stage of this fungus, which has been classified as Mycosphaerella capsellae. The ascocarp of M. capsellae is a cleistothecium, meaning asci are shielded from the environment prior to ascospore release. As means of asexual reproduction, P. capsellae produces chains of septate conidia. Conidia range in size between about 42-71μm in length and about 3μm in width. These chains of conidia are attached to a long conidiophore and stipe, connecting these asexual structures to the sterile hyphal network of the fungal body. In culture, P. capsellae appears black and white on potato dextrose agar (PDA). When observed under a microscope, P. capsellae appears a reddish-purple color due to the fungus' production of a purple-pink pigment. P. capsellae also is known to produce a mycotoxin, cercosporin, which increases the virulence of the pathogen.
Disease Signs/Symptoms, Cycle, and Control
Disease Signs and Symptoms
Infected crucifers display white lesions on leaves when infected by P. capsellae. These white lesions oftentimes have nonuniform shapes, and darken as the fungus matures on its host. Lesions on leaves initially can be 1-2mm in diameter, but can grow up to 10mm in diameter as the disease progresses. Leaves can fall off of host plants if infection is severe and widespread throughout a particular host. Gray or tan lesions may also appear on host stems; these lesions oftentimes harbor the sexual stage of P. capsellae, where ascospores are developed and released. Conidia can be found on the underside of leaves, oftentimes in locations corresponding to where lesions are present.
Disease Cycle
Conidia from the asexual structures of P. capsellae germinate at optimal temperatures of 20-24°C. At these temperate conditions and in ample humidity, conidia can be spread to new host plants via wind, water droplet splash, or by improperly sanitized farm equipment. These conidia penetrate new host leaves or stems and create infection. Crucifers, such as canola or rapeseed, are the primary host for this pathogen. In rare cases, cover crops or neighboring species of weeds can act as secondary hosts for the sexual stage of P. capsellae. P. capsellae overwinters as thick-walled mycelium on infected detritus in fields, and germinates again to infect new hosts as conditions become more ideal for spread. P. capsellae is a hemibiotroph, as indicated by its ability to keep host crucifers alive until host leaves fall off during severe infection.
Control Strategies
Many management strategies have been implemented in attempt to control the spread of P. capsellae. One common method of control is the use of fungicides as means of chemical control. The use of fungicides has been discovered to be ineffective at the control of P. capsellae, as this pathogen is resistant to most of the common fungicides utilized by farmers.
Cultural control methods are the most common management strategy that farmers use against P. capsellae. Methods such as crop rotation, proper sanitation of farm equipment, and planting crucifer crops with more space in between crops are effective methods of managing the spread of P. capsellae in fields. Sanitation of farm equipment and crop rotation are methods of reducing initial inoculum of conidia produced by P. capsellae.
Breeding genetic resistance towards P. capsellae is a promising method for disease management of this pathogen. Researchers across the world have been conducting genetic crosses of Brassica crops to find resistance genes that can make crops less susceptible to P. capsellae infection. Although this method of control is promising, P. capsellae has a genome that is rapidly changing, making it difficult for researchers to identify host resistance genes that remain effective against P. capsellae for substantial periods of time.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Canola diseases
Mycosphaerellaceae
Fungi described in 1887
Taxa named by Benjamin Matlack Everhart
Fungus species | Pseudocercosporella capsellae | [
"Biology"
] | 1,249 | [
"Fungi",
"Fungus species"
] |
11,068,876 | https://en.wikipedia.org/wiki/Colletotrichum%20higginsianum | Colletotrichum higginsianum is an ascomycete pathogen that causes anthracnose disease on many plants in the Brassicaceae, including Arabidopsis thaliana and many cultivated forms of Brassica and Raphanus.
Taxonomy and Phylogeny
Colletotrichum higginsianum belongs to the phylum of Ascomycota. The order this fungus is categorized into is Glomerellas. Its genus is Colletotrichum and its species is higginsianum. The genus of Colletrotrichum belongs to a class of fungi that are recognized for being a phytopathogen. There are over 248 different species of Colletotrichum and over 14 species complexes. The genus Colletotrichum was first proposed in 1831 (Jospeh, 1831). Colletotrichum higginsianum was originally discovered in 2012 by Dr. Richard J. O'Connell. He sequenced its genome through the use of short-read data from 454 GSFLX (350 bp) and Illumina GAII (100 bp) sequencing platforms and Sanger reads. Thus, unlocking a whole new realm of research for this interesting species. C. higginsianum forms part of a group of closely-related taxa that also includes C. destructivum, which is a pathogen to tobacco and legume plant species, and C. linicola, a flax pathogen.
Morphology
In order to identify Colletotrichum higginsianum, you would first start off searching for small, dark spots or water-soaked lesions on leaves, stems, or fruits. Reasoning one would look for these identifications is because Colletotrichum higginsianum produces spores in acervuli, which are fungal fruiting structures that break through the surface of the host tissue. While the fruiting structure of this fungus is growing on its host, it causes severe damage to the hosts tissue and cells. To make it even more interesting, Colletotrichum higginsianum additionally goes through multiple stages when infecting its host. In the initial stage, the fungus punctures through the host surface with appressoria. As time progresses, the hyphae inside the host cells will become bulbous biotrophic, which they can then proceed and transition into their final stage. During this final stage, the fungusi fully emerges, absorbing all the nutrients of the plant, essentially killing and destroying the host tissue. This would define its final stage as nectrotrophy (a parasitic process where an organism kills the living cells of its host and then feeds on the dead matter).
Ecology
Colletotrichum higginsianum is a hemibiotrophic fungus. This means that in order for this fungus to obtain energy, it "first establishes a biotrophic interaction by evading the plant’s defense mechanisms and later switches to a necrotrophic phase, in which it kills the host cells and feeds on them. Through research and studies, we have now observed that the role of a terpenoid in manipulating the host defense response was discovered through a forward chemical genetics approach, using Arabidopsis thaliana and C. higginsianum as the plantepathogen pair." Since this species is a pathogenic fungus, it can be found infecting species of the Brassicaceae family, including Arabidopsis thaliana, Brassica, and Raphanus. "Brassicaceae contains some 338 genera and more than 3,700 species of flowering plants distributed throughout the world". Additionally, Colletotrichum higginsianum can be found on multiple parts around the world since they infect common crops found globally. Data has shown us that the fungus does prefer to grow in environments that are tropical or subtropical. Some examples of countries would be Tunisia, China, and Hubei. Additionally, this fungusi is found in various countries in Europe. Another important factor is the temperature that the fungus can survive in. Colletotrichum species, including C. higginsianum, generally survive in temperatures ranging from 20-30 degrees Celsius.Laaslty, since this fungus can be located on a diversity of plant species and geographically, this makes controlling or the regulation of this fungus so much harder.
Overall Biology and Relevance for Humans
Being a fungus that can be found on multiple parts of the globe, Colletotrichum higginsianum is economically important for humans because it can infect thousands of different species of flowering species, such as but not limited to: basket-of-gold (Aurinia saxatilis), cabbage and relatives (genus Brassica), peppergrass (genus Lepidium), wasabi (Eutrema japonicum), and wild radish (Raphanus raphanistrum). This directly affects humans because it causes diseases to plants which results in decreased yield in crops. Additionally, since they are nectrophoic during its final stage, this kills and destroys the host tissue, resulting in more crops dying. In regions where they do not have the ability to expend extra resources on crops or agriculture, one sweep of this pathogenic fungusi could not only be detrimental to the plant species, but significantly decrease the production of food and medicine. It is also important to notate that if crops were to become infected with this fungus, it is very easy to spread to other plant species since this fungus can disperse its spores via wind and or water-splashing (Spores are embedded in a slimy matrix and can be spread to nearby plants by splashing water). This makes it even more of a challenge combating against this fungus and controlling its invasion. Now at this current time, there aren't any direct applications or use for Colletotrichum higginsianum. Thankfully, current studies are being conducted in order to maintain control of the anthracnose disease (group of a fungal diseases that causes dark lesions on leaves, stems, flowers, and fruits of many trees). "By recognizing host physical and chemical cues, C. higginsianum conidia differentiate melanized appressorium, an infection structure, at the tips of conidial germ tubes. Appressorium formation is required for successful infection since the fungus penetrates the cuticle and plant cell wall by utilization of enormous turgor pressure in melanized appressoria for further invasive growth. Thus, inhibition of melanized appressorium formation will facilitate the efficient control of anthracnose disease". This translates into the objective of seizing or preventing the formation of appressorium (a specialized structure that some parasitic fungi use to attach to and penetrate a host plant or animal) in order to maintain control of the fungal disease that infects plant species. Furthermore, lowering the infection rate of fungal pathogens in various plant species.
References
Sources
August Carl Joseph, Corda (1831). Sturm, Jakob (ed.). Deutschlands Flora in Abbildungen nach der Natur mit Beschreibungen (in German). Vol. 3. Nürnberg, Germany. pp. 33–64.
Yan, Y., Yuan, Q., Tang, J., Huang, J., Hsiang, T., Wei, Y., & Zheng, L. (2018). Colletotrichum higginsianum as a model for understanding host–pathogen interactions: A Review. International Journal of Molecular Sciences, 19(7), 2142. https://doi.org/10.3390/ijms19072142
Further reading
External links
higginsianum
Fungal plant pathogens and diseases
Fungi described in 1917
Fungus species | Colletotrichum higginsianum | [
"Biology"
] | 1,588 | [
"Fungi",
"Fungus species"
] |
11,068,880 | https://en.wikipedia.org/wiki/Colletotrichum%20trifolii | Colletotrichum trifolii is a fungal plant pathogen of alfalfa, causing the disease alfafa anthracnose. It is a biotroph, obtaining nutrients from the living plant cells before forming asexual spores. This fungus has two known races Bain and Essary.
Hosts and symptoms
Hosts
Colletotrichum trifolii is a pathogen to many forage crops. These include:
Alfalfa (most common)
Sweet clover
Burr clover
Subterranean clover
Crimson clover
Red clover
There have been no attempts to discover a full host range outside beyond the aforementioned.
Symptoms
This pathogen causes anthracnose in these plants. The visual symptoms include:
Scattered straw colored plants in the field
Yellowing of leaves
Formation of a "shepherds crook"
Greyish brown lesions on lower stem leading to crown rot
Once parts of the plant die parts of the leaves will turn tan making the black fruiting bodies of Colletotrichum trifolii especially visible to the observer.
Environment
Anthracnose from Colletotrichum trifolii most severely affects crops east of the Mississippi River and south of Wisconsin. It is also found in California and southern Arizona and in less severe cases, Colletotrichum trifolii has a moderate pressure across the whole United States except around the Rocky Mountains. It is also found in Europe, South America, and Canada. This pathogen grows the best around 25 °C. Colletotrichum trifolii also needs substantial moisture for a minimum of twelve hours to infect the plant although once infected it can survive on the plant in dry weather.
Management
There are only a couple ways to manage Colletotrichum trifolii. The first way is to start scouting right away in early summer. If this pathogen is found in a field rotate crops in the field away from forage crops for at least two year. Another method of management is planting resistant varieties. It is recommended to plant only varieties with a minimum moderate resistant rating but if Colletotrichum trifolii has been a problem in the past only plant highly resistant varieties. The last management tactic is to delay planting until after Colletotrichum trifolii is normally a problem. This means waiting until late summer, around August, doing this allows the plants to become a good stand during late summer and fall while escaping most of the time when the pathogen is prevalent. This method is not very practical especially with the resistant varieties of today.
References
trifolii
Fungal plant pathogens and diseases
Eudicot diseases
Fungi described in 1906
Fungus species | Colletotrichum trifolii | [
"Biology"
] | 531 | [
"Fungi",
"Fungus species"
] |
11,068,885 | https://en.wikipedia.org/wiki/Coprinopsis%20psychromorbida | Coprinopsis psychromorbida or cottony snow mold is a cause of snow mold. It is a basidiomycete, a psychrophile, and a plant pathogen.
Physiology
C. psychromorbida can thrive at least down to , optimally , and ceases growth at .
Hosts
Grows as a snow mold in wheat, rye, and other grasses (Poaceae) and can also cause storage rotting in apple and pear.
References
Fungi described in 1981
Fungal plant pathogens and diseases
Wheat diseases
Rye diseases
Pear tree diseases
psychromorbida
Fungus species | Coprinopsis psychromorbida | [
"Biology"
] | 124 | [
"Fungi",
"Fungus species"
] |
11,068,891 | https://en.wikipedia.org/wiki/Athelia%20arachnoidea | Athelia arachnoidea is a corticioid fungus in the family Atheliaceae. The species forms thin, white, cobwebby basidiocarps (fruit bodies) and typically occurs saprotrophically on leaf litter and fallen wood. It can, however, also be a facultative parasite of lichens and can additionally be a plant pathogen (typically found in its asexual Fibularhizoctonia carotae state), causing "crater rot" of stored carrots.
References
Fungal plant pathogens and diseases
Eudicot diseases
Atheliales
Fungi described in 1844
Taxa named by Miles Joseph Berkeley
Lichenicolous fungi
Fungus species | Athelia arachnoidea | [
"Biology"
] | 145 | [
"Fungi",
"Fungus species"
] |
11,068,896 | https://en.wikipedia.org/wiki/Scytinostroma%20galactinum | Scytinostroma galactinum is a fungal plant pathogen infecting apples.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Apple tree diseases
Russulales
Fungi described in 1851
Taxa named by Elias Magnus Fries
Fungus species | Scytinostroma galactinum | [
"Biology"
] | 57 | [
"Fungi",
"Fungus species"
] |
11,068,899 | https://en.wikipedia.org/wiki/Ceratobasidium%20ochroleucum | Ceratobasidium ochroleucum is a species of fungus in the family Ceratobasidiaceae. Basidiocarps are effused and web-like and were originally described from Brazil, causing a thread blight of apple and quince trees. The fungus was subsequently reported as a leaf disease on orchard crops in North America, but since descriptions of Ceratobasidium orchroleucum vary considerably and no type specimen exists, its identity remains unclear. Roberts (1999) considered it a "nomen dubium".
Taxonomy
The species was originally described from Brazil in 1898 as Hypochnopsis ochroleuca. American mycologist E.A. Burt subsequently transferred it to Corticium, then used as a catch-all genus for effused corticioid fungi, but the combination in Corticium was illegitimate since Elias Magnus Fries had already described a different Corticium ochroleucum in 1838. Burt accordingly gave the Brazilian species the new name Corticium stevensii. The species was transferred to Ceratobasidium in 1973, but the combination was invalid and should have been based on Noack's original epithet, a mistake eventually corrected in 1993.
References
Fungal plant pathogens and diseases
Cantharellales
Fungi described in 1898
Fungus species | Ceratobasidium ochroleucum | [
"Biology"
] | 273 | [
"Fungi",
"Fungus species"
] |
11,068,905 | https://en.wikipedia.org/wiki/Grovesinia%20pyramidalis | Grovesinia pyramidalis is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Sclerotiniaceae
Fungus species
Fungi described in 1983 | Grovesinia pyramidalis | [
"Biology"
] | 40 | [
"Fungi",
"Fungus species"
] |
11,068,913 | https://en.wikipedia.org/wiki/Neofabraea%20malicorticis | Neofabraea malicorticis is a plant pathogen that causes bull's-eye rot on apple and pear.
References
Fungal tree pathogens and diseases
Apple tree diseases
Pear tree diseases
Dermateaceae
Fungus species
Fungi described in 1913 | Neofabraea malicorticis | [
"Biology"
] | 49 | [
"Fungi",
"Fungus species"
] |
11,068,916 | https://en.wikipedia.org/wiki/Neofabraea%20perennans | Neofabraea perennans is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Dermateaceae
Fungus species | Neofabraea perennans | [
"Biology"
] | 37 | [
"Fungi",
"Fungus species"
] |
11,068,921 | https://en.wikipedia.org/wiki/Nectria%20ramulariae | Nectria ramulariae is a plant pathogenic fungus.
References
Fungal plant pathogens and diseases
ramulariae
Fungi described in 1818
Fungus species | Nectria ramulariae | [
"Biology"
] | 31 | [
"Fungi",
"Fungus species"
] |
11,068,924 | https://en.wikipedia.org/wiki/Neonectria%20ditissima | Neonectria ditissima (syn. Neonectria galligena) is a fungal plant pathogen. It causes cankers that can kill branches of trees by choking them off. Apple and beech trees are two susceptible species.
Host range
Neonectria ditissima host range encompass a variety of hardwood tree species such as, Fagus, Populus, Salix, Betula and Acer species. These tree species population are present in both America and Europe. Phylogenetic studies have revealed genetic divergence among both populations, at specific loci (ß-tubulin, RPB2). However, due to high levels of within-population diversity of the American populations, it has been hypothesized that America is N. ditissima place of origin.
Disease management
Neonectria ditissima is a difficult pathogen to eradicate—but there are many ways to limit its spread and infection rate. Effective control requires a combination of cultural and chemical treatments.
Cultural control
Multiple cultural techniques can manage the spread of N. ditissima. To minimize the number of wounds the pathogen can enter through, select trees that are well adapted to the local climate. In certain areas, trees must be able to resist damage due to environmental stresses such as cold temperatures. If cankers are present, it is important to prune out the damaged tissue in dry conditions. Dry conditions are unfavorable to the pathogen because it prohibits the development of fruiting structures and spore dispersal. It is essential to disinfect the equipment before and after pruning to prevent the spread of the pathogen to uninfected trees. Cankered prunings must be removed from the area and burned to eliminate the risk of continuing spore production. It is crucial to limit the use of high nitrogen, especially in manure, because it encourages and facilitates N. ditissima.
Chemical control
Fungicides that control N. ditissima are limited. Infection by N. ditissima often occurs through wounds in the autumn and spring-summer period, therefore, it's best to apply fungicides at those times. Fungicides prevent or decrease sporulation of existing cankers, which in turn decreases inoculum available to spread the pathogen. Fungicides may also protect trees from N. ditissima through a fungitoxic deposit over favorable infection sites. A mixture of carbendazim and a scab fungicide, such as dithianon, is the suggested treatment in areas with a severe canker problem. In areas with a reduced risk of canker, it is recommended that a scab fungicide be applied in the spring-summer and copper oxychloride applied at leaf-fall to avoid infection. Although scab fungicides are commonly used for managing apple scab, cankers are also controlled when applied at the correct time. Thiophanate-methyl is another fungicide that is highly effective because it protects trees against the pathogen and suppresses sporulation of already infected plants. However, the application of thiophanate-methyl is limited due to its harm on organisms such as mites.
References
Fungal tree pathogens and diseases
Apple tree diseases
Nectriaceae
Fungi described in 1865
Taxa named by Edmond Tulasne
Fungus species | Neonectria ditissima | [
"Biology"
] | 679 | [
"Fungi",
"Fungus species"
] |
11,068,927 | https://en.wikipedia.org/wiki/Cylindrocarpon%20magnusianum | Cylindrocarpon magnusianum is a fungal plant pathogen that causes root rot in alfalfa and red clover.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Eudicot diseases
Nectriaceae
Fungi described in 1928
Fungus species | Cylindrocarpon magnusianum | [
"Biology"
] | 58 | [
"Fungi",
"Fungus species"
] |
11,068,930 | https://en.wikipedia.org/wiki/Sri%20Lanka%20Signals%20Corps | The Sri Lanka Signals Corps (SLSC) (Sinhalese: ශ්රී ලංකා සංඥා බලකාය Shri Lanka Sana Balakaya) is a combat support corps of the Sri Lanka Army, responsible for providing military communications, information technology and electronic warfare support. The corps is made up of a signals brigade, ten regular regiments and one volunteer regiment. It is responsible for installing, maintaining and operating all types of telecommunications equipment and information systems. It is headquartered at the Panagoda Cantonment.
Colonel Commandant of the SL Signals and Chief Signal Officer of the Sri Lanka Army Commander Signals Brigade, operationally in charge of all units and sub-units in the field.
The flag and cap badge feature Mercury, the winged messenger of the gods, who is referred to by members of the corps as "Jimmy".
History
Established on October 19, 1943, as a part of the Ceylon Defence Force it was reformed as a troop of signals February 9, 1950 following the formation of the Ceylon Army in 1949. The initial task of this troop was to provide communications between Army HQ and its branches. In 1949, the Volunteer Signals unit was commanded by Lt Col CR De Silva. By the end of 1950 this troop had 1 Officer and 17 other ranks and their tasks included establishing a signals office at Army HQ, provision of a signal dispatch service, manning a switch board and the construction and maintenance of underground as well as field cables. In May 1951 another Signals Office was established in Diyatalawa to serve the Garrison HQ which was just formed at that time. By October 1, 1951, the troop was raised to a squadron with a strength of 4 officers and 142 other ranks.
In 1951 formal approval was granted to wear the Royal Signals badges with the additional scroll "CEYLON" on it and to adopt the Royal Signals march Begone Dull Care as the regimental march of the Ceylon Signals Corps and in 1959 the 1st Regiment of the Ceylon Signals was formed with Lt Col DV Brohier was appointed as its first Commanding Officer. In 1962 following the attempted military coup the 2nd volunteer signal regiment was disbanded and its remaining personnel transferred to form the National Service Regiment (NSR).
In 1972 with Sri Lanka proclaiming itself a republic, the Corps was renamed as the Sri Lanka Signals Corps. In 1980 a new Volunteer squadron was raised. The Corps has expanded to a level of a Signals Brigade with integral signals units under HQ Chief Signal Officer at the highest level of command in performing the classic role. The Signals Corps provides support to the combat and support arms by providing communications, electronic warfare and information technology support in the battle field and at the rear. All these signal units and sub-units administratively come under the aegis of the Regimental Centre located at Panagoda Cantonment.
Organization
The corps also runs a School of Signals in Kandy, established on 15 July 1991. The school is currently under the command of Col SJKD Jayawardena USP psc, with Major KVA Kodikara psc serving as chief instructor. The Sri Lanka Army established a Directorate of Information Technology under the Signal Corps on 1 March 2010; its current director is Major General P A J Peiris ndu.
Independent Signal Squadron
AHQ Independent Signal Squadron
Independent Composite Signal Squadron
Electronic Warfare Squadron
PA Squadron
LED Squadron
Equipment
Man-portable Surveillance and Target Acquisition Radars (MSTAR)
TRC 274 wideband tactical jammers
Past command staff
Centre Commandants
Colonel Commandants
Notable officers
Lieutenant Colonel Gotabhaya Rajapaksa, RWP, RSP - President of Sri Lanka
Lieutenant Colonel DV Brohier - First Commanding Officer, Ceylon Signals Corps
Brigadier C. T. Caldera - second Commanding Officer, Ceylon Signals Corps
Lieutenant Colonel Basil R. Jesudasan - former Commanding Officer, 2nd Volunteer Signals, Ceylon Signals Corps & accused conspirator in the 1962 coup d'état attempt
Major General Piyal Abeysekera (also known as E.P. de Z. Abeysekera) USP, MSc - former Deputy Chief of Staff of Sri Lanka Army
Major General W.J.T.K. Fernando psc - former CO, 1SLSC
Major General C.J. Abayaratna VSV, USP - 1st Colonel Commandant, SLSC, former Signals Brigade Commander & former CO, 1SLSC
Major General A.M.C.W.B. Senewiratne VSV, USP, psc - 4th Colonel Commandant, SLSC & former CO, 3 SLSC
Major General Y.S.A. de Silva USP - 5th Colonel Commandant, SLSC, former Signals Brigade Commander & former CO 4 SLSC
Major General Tuan Fadyl Meedin RSP, Ldmc - 6th Colonel Commandant, SLSC, 1st Chief Signals Officer (CSO), Chief Innovations Officer (CIO), Signals Brigade Commander, Chief Controller- Centre for Research & Development (MOD), Centre Commandant & former CO- 1 SLSC
Major General K.A.W.S. Ratnayake ndu - 10th Chief Signal Officer - Sri Lanka Army, 16th Regimental Commander and Colonel Commandant - SLSC
Alliances
- Royal Corps of Signals
Order of precedence
Abbreviation
CSO - Chief Signal Officer
PWV- Parama Weera Vibhushanaya
WV - Weerodara Vibhushanaya
WWV - Weera Wickrama Vibhushanaya
RWP - Rana Wickrama Padakkama
RSP - Rana Sura Padakkama
VSV - Vishista Sewa Vibhushanaya
USP -Utthama Seva Padakkama
psc - passed staff college
ndu - national defense university
IT - Information Technology
CS - Cyber Security
CT - Communication Technology
References
External links
Sri Lanka Army
Sri Lanka Signals Corps
Signals Corps
Signals Corps
Military communications
Military units and formations of Ceylon in World War II | Sri Lanka Signals Corps | [
"Engineering"
] | 1,185 | [
"Military communications",
"Telecommunications engineering"
] |
11,068,938 | https://en.wikipedia.org/wiki/Mycosphaerella%20pomi | Mycosphaerella pomi is a fungus in the Mycosphaerellaceae family.
It was first described by Giovanni Passerini in 1878 as Sphaerella pomi, and transferred to the genus, Mycosphaerella, in 1897 by Gustav Lindau. The species epithet, pomi, is the genitive of Latin, pomum ("apple") and refers to the fact that this is a fungus found on apples.
See also
List of Mycosphaerella species
References
Fungal plant pathogens and diseases
pomi
Fungi described in 1897
Fungus species | Mycosphaerella pomi | [
"Biology"
] | 119 | [
"Fungi",
"Fungus species"
] |
11,068,943 | https://en.wikipedia.org/wiki/Cytospora%20personata | Cytospora personata is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Diaporthales
Fungus species
Taxa named by Elias Magnus Fries
Fungi described in 1818 | Cytospora personata | [
"Biology"
] | 47 | [
"Fungi",
"Fungus species"
] |
11,068,950 | https://en.wikipedia.org/wiki/Cytospora%20sacculus | {{Taxobox
| name = Cytospora sacculus
| regnum = Fungi
| phylum = Ascomycota
| classis = Sordariomycetes
| subclassis = Sordariomycetidae
| ordo = Diaporthales
| familia = Valsaceae
| genus = Cytospora| species = C. sacculus| binomial = Cytospora sacculus
| binomial_authority = (Schwein.) Gvrit. (1969)
}}Cytospora sacculus''''' is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Diaporthales
Fungal plant pathogens and diseases
Fungus species
Taxa named by Lewis David de Schweinitz | Cytospora sacculus | [
"Biology"
] | 166 | [
"Fungi",
"Fungus species"
] |
11,068,956 | https://en.wikipedia.org/wiki/Erysiphe%20pisi | Erysiphe pisi is a plant pathogen that causes powdery mildew on several plant species.
References
Fungal plant pathogens and diseases
pisi
Fungi described in 1821
Fungus species | Erysiphe pisi | [
"Biology"
] | 38 | [
"Fungi",
"Fungus species"
] |
11,068,966 | https://en.wikipedia.org/wiki/Erysiphe%20cruciferarum | Erysiphe cruciferarum is a plant pathogen of the family Erysiphaceae, which causes the main powdery mildew of crucifers, including on Brassica crops, such as cauliflower, cabbage, broccoli, and Brussels sprouts. E. cruciferarum is distributed worldwide, and is of particular concentration in continental Europe and the Indian subcontinent. E. cruciferarum is an ascomycete fungus that has both sexual and asexual stages. It is also an obligate parasite that appears to have host specificity; for example, isolates from turnip will not infect Brussels sprout, and vice versa. While being a part of the family Erysiphaceae, it belongs to those members in which the conidia are formed singly and whose haustoria are multilobed.
This species is also being evaluated as a potential biological control for the invasive plant garlic mustard.
Signs and symptoms
Erysiphe cruciferarum exhibits typical powdery mildew characteristics, appearing as small radiating, diffuse colonies of superficial white mycelium on the surface of the leaf; usually both sides of the leaf show white, powdery fungal growth. Additional signs of the pathogen would be that its conidia are singly produced (not in chains) and are ovoid to cylindrical in shape, ranging from 42.5–57 μm × 14.5–20.5 μm in size. Also, E. cruciferarum has rather variable appressoria, differing from lobed to simple, and haustoria that are multilobed. Severe, advanced infections produce a dense white powdery covering of leaves, stems, and seed crop pods. On cauliflower and cabbage, heavily diseased plants show chlorosis, early defoliation, and necrosis of the tips of young leaves. Colonies may be gray and restricted in size on resistant cultivars as the host reaction produces black speckling beneath the colony. On Brussels sprout, gray or purple symptoms occur on the stems, while on the sprouts there may be white colonies or fine black speckling in radiating lines.
Disease diagnosis is determined on the basis of anamorph morphology and host.
Disease cycle
Erysiphe cruciferarum is an obligate parasite. They overwinter as resting spores on plant tissues or in the soil. These resting spores are called Chasmothecia. Chasmothecium are signature of all powdery mildews and can be identified by their appendages. When the environment is favorable——the chasmothecia will release asci which contain ascospores. Ascospores are the sexual spore of the powdery mildew. They are dispersed primarily by wind and germinate on the surface of plant tissue. They infect and feed on the plant via haustoria. Secondary infection is caused by the production and dispersal of conidia (asexual spores). Chasmothecium are then produced on vegetative surface of host in late summer.
Environment
Erysiphe cruciferarum produces well when it is in moderate to high humidity with moderate temperatures. Temperatures between 70–80 °F (22–27 °C) with low relative humidity during the day and high relative humidity at night are favorable ranges. This pathogen has a wide host range. It can infect many wild plants along with cash crops. It has the ability to jump from field weeds to cultivated crops within a single season if the conditions are right. It will reduce photosynthesis and affect yields on cultivated crops. With that, this pathogen can be very troublesome in a greenhouse and protected environment, as these spaces provide ideal growing conditions. Protected growing environments tend to have temperatures and humidity within the pathogen's desired range to reproduce. Wind and rain can also spread the spores of E. cruciferarum. Adding vegetative wind barriers can impede the spores' travel into the cultivated field and possibly lower the chance of infection. High planting densities will decrease the distance and time needed to travel to a new healthy host. Lowering the planting density or adding space between rows can aid in slowing the spores' spread.
Management
BiologicalAQ10 is a hyperparasite of powdery mildew. It is a fungus, Ampelomyces quisqualis, and should be applied preventatively.
CulturalIf resistant varieties are available, they should be used. Other "volunteer" host plants in the area should be eliminated and infected debris should be cleared whenever possible. Crops should be rotated with non-crucifer crops.
ChemicalOils like neem or jojoba can be sprayed on surface of plant to help with mild-moderate mildew infections. Fungicides like azoxystrobin and sulfur can be used to prevent an infection or kill an existing infection.
Importance
Erysiphe cruciferarum is also being studied for its ability to be used as a biological control to curtail garlic mustards whose growth is widely unchecked across the country. E. cruciferarum could provide an effective way to control garlic mustard without human intervention. E. cruciferarum has the ability to reduce the vitality and vigor of host plants by lowering the efficiency of photosynthesis, which in turn will lower the plant's ability to produce seed and survive another generation. This pathogen is somewhat host-specific in that it targets plants in the genus Brassica. This pathogen can also infect Brassica crops so it must be used with caution or must be engineered to only attack garlic mustard.
Pathogenesis
Erysiphe cruciferarum is a fungal pathogen that belongs to the phylum Ascomycota. The pathogen overwinters in survival structures known as ascospores. The powdery mildew initially appears as white, powdery spots formed on leaf surfaces, shoots, and sometimes flowers or fruits. Over time, the spots spread over a larger area of leaves and stems. Eventually, leaves infected with powdery mildew may turn yellow in color and proceed to die or fall off. In some cases, fungal growth causes leaves to twist or distort in shape. Specifically, powdery mildew functions by decreasing the fruit production of plants. The ascospores survive on leaf material and cause it to fall onto the ground. Certain biological fungicides, such as Serenade or sulfur products, can be used on plants to inhibit powdery mildew infection.
References
Fungal plant pathogens and diseases
Vegetable diseases
cruciferaum
Fungi described in 1967
Fungus species | Erysiphe cruciferarum | [
"Biology"
] | 1,363 | [
"Fungi",
"Fungus species"
] |
11,068,969 | https://en.wikipedia.org/wiki/Erysiphe%20betae | Erysiphe betae is a fungal plant pathogen. It is a form of powdery mildew that can affect crops of sugar beet, that could cause up to a 30% yield loss. The fungus occurs worldwide in all regions where sugar beet is grown and it also infects other edible crops, e.g. beetroot.
Identification
This pathogen is a strict obligated parasite, and therefore can only be identified when in planta. Often to properly identify this pathogen, some form of microscopic analysis is needed when it is only found on one type of plant. This can be done through isolation and observation of cleistothecia, which are the product of sexual reproduction.
Disease symptoms
Symptoms appear as dirty white, circular, floury patches on either sides of the leaves.
Under favourable environmental conditions, entire leaves, stems, floral parts and pods are affected.
The whole leaf may be covered with powdery mass.
If persistent, mild chlorosis or necrosis can also occur.
Survival and spread
The pathogen survives overwinter through cleistothecia which are present in crop debris in the field and which contain ascospores (sexual spores). Infection occurs when ascospores or conidia (asexual spores) are able to germinate and penetrate the plant's leaf. After infection, the pathogen, now growing as hyphae within the leaf, begins producing conidia on short conidiophores. Both ascospores and conidia can be the source of a primary inoculum or "first infection". The production of which type of spore is determined by weather conditions and time of year. Conidia can travel long distances through the air.
Favourable conditions
Disease development is favored by high temperatures (15-28 °C) coupled with low humidity (<60% humidity), and low or no rainfall, with wind.
Description
This fungus, like all powdery mildews, has a white powdery appearance. It appears on leaves in the summer time. Infection normally begins on older leaves, typically close to the junction between the lamina and petiole, and it develops on both ab- and adaxial surfaces.
Pathogenicity
This pathogen decreases yields in crops by the reduction of light available for photosynthesis in the leaves of plants. It also causes leaf and shoot deformities. This will affect the yield and the quality of seed crops as well as visual appearance and quality of leaf crops. In the case of Erysiphe betae, entry into the cell involves both mechanical penetration and enzymatic degradation of the cuticle and the cell wall.
Plant defenses
The fungus can produce some cell wall degrading enzymes include pectin lyases and polygalacturonases. Plants can contain an array of specialized inhibitors that counteract the effects of these enzymes.
Methods of control
In the case of control against Erysiphe betae, not much is known about how to totally eradicate this disease once it has taken hold of the crop. It must therefore be assumed that the best method of control is prevention. This can be done using fungicides. Some genes have been identified in wild species.
References
Other sources
Dr. Alan J. Silverside (2002, September). Erysiphe cichoracearum DC. var. cichoracearum. Retrieved November 4, 2007 from, Website: https://web.archive.org/web/20080208144943/http://www-biol.paisley.ac.uk/bioref/Fungi_ascomycetes/Erysiphe_cichoracearum.html
Robin Philippe (n.a.). Powdery mildew. Retrieved November 4, 2007 from, Web site: http://www.inra.fr/hyp3/pathogene/6erybet.htm
Fungal plant pathogens and diseases
Food plant pathogens and diseases
betae
Fungi described in 1903
Fungus species | Erysiphe betae | [
"Biology"
] | 824 | [
"Fungi",
"Fungus species"
] |
11,068,975 | https://en.wikipedia.org/wiki/Gymnosporangium%20clavipes | Gymnosporangium clavipes is a plant pathogen, a fungus that causes cedar-quince rust. Similar to Gymnosporangium juniperi-virginianae and Gymnosporangium globosum, the fungus infects a wide range of Rosaceae, such as apple, hawthorn and quince trees, and also requires an evergreen host such as eastern red cedar or a number of other juniper species to complete its life cycle.
References
External links
Pucciniales
Apple tree diseases
Fruit tree diseases
Fungal tree pathogens and diseases
Galls
Fungi described in 1873
Fungus species | Gymnosporangium clavipes | [
"Biology"
] | 121 | [
"Fungi",
"Fungus species"
] |
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