id int64 580 79M | url stringlengths 31 175 | text stringlengths 9 245k | source stringlengths 1 109 | categories stringclasses 160
values | token_count int64 3 51.8k |
|---|---|---|---|---|---|
12,098,689 | https://en.wikipedia.org/wiki/Systems%20analyst | A systems analyst, also known as business technology analyst, is an information technology (IT) professional who specializes in analyzing, designing and implementing information systems. Systems analysts assess the suitability of information systems in terms of their intended outcomes and liaise with end users, software vendors and programmers in order to achieve these outcomes. A systems analyst is a person who uses analysis and design techniques to solve business problems using information technology. Systems analysts may serve as change agents who identify the organizational improvements needed, design systems to implement those changes, and train and motivate others to use the systems.
Industry
, the sectors employing the greatest numbers of computer systems analysts were state government, insurance, computer system design, professional and commercial equipment, and company and enterprise management. The number of jobs in this field is projected to grow from 487,000 as of 2009 to 650,000 by 2016. According to the U.S. Bureau of Labor Statistics (BLS), Occupational Outlook predicts the need for Computer Systems Analysts as growing 25% in 2012 to 2022 and gradually decreasing their estimates and now predict the years 2022 to 2032 as only 10% growth. Saying "Many of those openings are expected to result from the need to replace workers who transfer to different occupations or exit the labor force, such as to retire."
This job ranked third best in a 2010 survey, fifth best in the 2011 survey, 9th best in the 2012 survey and the 10th best in the 2013 survey.
See also
Business analyst
Change management analyst
Data analyst
Software analyst
References
External links
Computer Systems Analysts in the Occupational Outlook Handbook from the Bureau of Labor Statistics, a unit of the United States Department of Labor
Systems analysis
Business occupations
Computer occupations
de:Systemanalyse#Informatik | Systems analyst | Technology | 351 |
1,409,766 | https://en.wikipedia.org/wiki/United%20States%20Exploring%20Expedition | The United States Exploring Expedition of 1838–1842 was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States. The original appointed commanding officer was Commodore Thomas ap Catesby Jones. Funding for the original expedition was requested by President John Quincy Adams in 1828; however, Congress would not implement funding until eight years later. In May 1836, the oceanic exploration voyage was finally authorized by Congress and created by President Andrew Jackson.
The expedition is sometimes called the U.S. Ex. Ex. for short, or the Wilkes Expedition in honor of its next appointed commanding officer, United States Navy Lieutenant Charles Wilkes. The expedition was of major importance to the growth of science in the United States, in particular the then-young field of oceanography. During the event, armed conflict between Pacific islanders and the expedition was common and dozens of natives were killed in action, as well as a few Americans.
Preparations
Through the lobbying efforts of Jeremiah N. Reynolds, the United States House of Representatives passed a resolution on May 21, 1828, requesting President John Quincy Adams to send a ship to explore the Pacific. Adams was keen on the resolution and ordered his Secretary of the Navy to ready a ship, the Peacock. The House voted an appropriation in December but the bill stalled in the US Senate in February 1829. Then, under President Andrew Jackson, Congress passed legislation in 1836 approving the exploration mission. Again, the effort stalled under Secretary of the Navy Mahlon Dickerson until President Martin Van Buren assumed office and pushed the effort forward.
Originally, the expedition was under the command Commodore Jones, but he resigned in November 1837, frustrated with all of the procrastination. Secretary of War Joel Roberts Poinsett, in April 1838, then assigned command to Wilkes, after more senior officers refused the command. Wilkes had a reputation for hydrography, geodesy, and magnetism. Additionally, Wilkes had received mathematics training from Nathaniel Bowditch, triangulation methods from Ferdinand Hassler, and geomagnetism from James Renwick.
Personnel included naturalists, botanists, a mineralogist, a taxidermist, and a philologist. They were carried aboard the sloops-of-war (780 tons), and (650 tons), the brig (230 tons), the full-rigged ship Relief, which served as a store-ship, and two schooners, Sea Gull (110 tons) and (96 tons), which served as tenders.
On August 18, 1838, the vessels left the naval port of Hampton Roads, Virginia. The fleet then headed to Madeira, taking advantage of the prevailing winds.
Ships and personnel
The expedition consisted of nearly 350 men, many of whom were not assigned to any specific vessel. Others served on more than one vessel.
Ships
– sloop-of-war, 780 tons, 18 guns, flagship
– sloop-of-war, 650 tons, 22 guns
– full-rigged ship, 468 tons, 7 guns
– brig, 230 tons, 10 guns
– schooner, 110 tons, 2 guns
– schooner, 96 tons, 2 guns
– brig, 250 tons, 2 guns
Command
Charles Wilkes – Expedition commander and commandant of Vincennes
Cadwalader Ringgold – Lieutenant commandant of Porpoise
Andrew K. Long – Lieutenant commandant of Relief
William L. Hudson – Commandant of Peacock
Samuel R. Knox – Commandant of Flying Fish
James W. E. Reid – Commandant of Sea Gull
Naval officers
James Alden – Lieutenant
Daniel Ammen - Passed midshipman
Thomas A. Budd – Lieutenant and cartographer
Simon F. Blunt – Passed midshipman
Augustus Case – Lieutenant
George Colvocoresses – Midshipman
Edwin De Haven – Acting Master
Henry Eld – Midshipman
George F. Emmons – Lieutenant
Charles Guillou – Assistant surgeon
William L. Maury – Lieutenant
William Reynolds – Passed midshipman
Richard R. Waldron – Purser
Thomas W. Waldron – Captain's clerk
Scientific corps
Alfred T. Agate – Artist
Joseph Drayton – Artist
William Brackenridge – Assistant botanist
Joseph P. Couthouy – Conchologist
James D. Dana – Mineralogist and geologist
Horatio Hale – Philologist
Titian Peale – Naturalist
Charles Pickering – Naturalist
William Rich – Botanist
History
Expedition
First part
Wilkes was to search in the Atlantic for various vigias or shoals, such as those reported by John Purdy, but failed to corroborate those claims for the locations given. The squadron arrived in the Madeira Islands on September 16, 1838, and Porto Praya on October 6. The Peacock arrived at Rio de Janeiro on November 21, and the Vincennes with brigs and schooners on November 24. However, the Relief did not arrive until the November 27, setting a record for slowness, 100 days. While there, they used Enxados Island in Guanabara Bay for an observatory and naval yard for repair and refitting.
The Squadron did not leave Rio de Janeiro until January 6, 1839, arriving at the mouth of the Río Negro on January 25. On February 19, the squadron joined the Relief, Flying Fish, and Sea Gull in Orange Harbor, Hoste Island, after passing through Le Maire Strait. While there, the expedition came in contact with the Fuegians. Wilkes sent an expedition south in an attempt to exceed Captain Cook's farthest point south, 71°10'.
The Flying Fish reached 70° on March 22, in the area about north of Thurston Island, and what is now called Cape Flying Fish, and the Walker Mountains. The squadron joined the Peacock in Valparaiso on May 10, but the Sea Gull was reported missing. On June 6, the squadron arrived at San Lorenzo, off Callao for repair and provisioning, while Wilkes dispatched the Relief homewards on June 21. Leaving South America on July 12, the expedition reached Reao of the Tuamotu Group on August 13, and Tahiti on September 11. They departed Tahiti on October 10.
The expedition then visited Samoa and New South Wales, Australia. In December 1839, the expedition sailed from Sydney into the Antarctic Ocean and reported the discovery of the Antarctic continent on January 16, 1840, when Henry Eld and William Reynolds aboard the Peacock sighted Eld Peak and Reynolds Peak along the George V Coast. On the January 19, Reynolds spotted Cape Hudson. On January 25, the Vincennes sighted the mountains behind the Cook Ice Shelf, similar peaks at Piner Bay on January 30, and had covered of coastline by February 12, from 140° 30' E. to 112° 16' 12"E., when Wilkes acknowledged they had "discovered the Antarctic Continent." Named Wilkes Land, it includes Claire Land, Banzare Land, Sabrina Land, Budd Land, and Knox Land. They charted of Antarctic coastline to a westward goal of 105° E., the edge of Queen Mary Land, before departing to the north again on February 21.
The Porpoise came across the French expedition of Jules Dumont d'Urville on January 30. However, due to a misunderstanding of each other's intentions, the Porpoise and Astrolabe were unable to communicate. In February 1840, some of the expedition were present at the initial signing of the Treaty of Waitangi in New Zealand. Some of the squadron then proceeded back to Sydney for repairs, while the rest visited the Bay of Islands, before arriving in Tonga in April. At Nuku'alofa they met King Josiah (Aleamotu'a), and the George (Taufa'ahau), chief of Ha'apai, before proceeding onwards to Fiji on May 4. The Porpoise surveyed the Low Archipelago, while the Vincennes and Peacock proceeded onwards to Ovalau, where they signed a commercial treaty with Tanoa Visawaqa in Levuka. Edward Belcher's visited Ovalau at the same time. Hudson was able to capture Vendovi, after holding his brothers Cocanauto, Qaraniqio, and Tui Dreketi (Roko Tui Dreketi or King of Rewa Province) hostage. Vendovi was deemed responsible for the attack against US sailors on Ono Island in 1836. Vendovi was taken back to the US, but died shortly after his arrival in New York. His skull was then added to the expedition collections and put on display in the Patent Office building in Washington, D.C.
In July 1840, two members of the party, Lieutenant Underwood and Wilkes' nephew, Midshipman Wilkes Henry, were killed while bartering for food in western Fiji's Malolo Island. The cause of this event remains equivocal. Immediately prior to their deaths, the son of the local chief, who was being held as a hostage by the Americans, escaped by jumping out of the boat and running through the shallow water for shore. The Americans fired over his head. According to members of the expedition party on the boat, his escape was intended as a prearranged signal by the Fijians to attack. According to those on shore, the shooting actually precipitated the attack on the ground. The Americans landed sixty sailors to attack the hostile natives. Close to eighty Fijians were killed in the resulting American reprisal and two villages were burned to the ground.
Return route
On August 9, after three months of surveying, the squadron met off Macuata. The Vincennes and Peacock proceeded onwards to the Sandwich Islands, with the Flying Fish and Porpoise to meet them in Oahu by October. Along the way, Wilkes named the Phoenix Group and made a stop at the Palmyra Atoll, making their group the first scientific expedition in history to visit Palmyra. While in Hawaii, the officers were welcomed by Governor Kekūanaōʻa, King Kamehameha III, his aide William Richards, and the journalist James Jackson Jarves. The expedition surveyed Kauai, Oahu, Hawaii, and the peak of Mauna Loa. The Porpoise was dispatched in November to survey several of the Tuamotus, including Aratika, Kauehi, Raraka, and Katiu, and then proceeded to Penrhyn before returning to Oahu on 24 March.
On April 5, 1841, the squadron departed Honolulu, the Porpoise and Vincennes for the Pacific Northwest, the Peacock and Flying Fish to resurvey Samoa, before rejoining the squadron. Along the way, the Peacock and Flying Fish surveyed Jarvis Island, Enderbury Island, the Tokelau Islands, and Fakaofo. The Peacock followed this with surveys of the Tuvalu islands of Nukufetau, Vaitupu, and Nanumanga in March. In April, the Peacock surveyed the Gilbert Islands of Tabiteuea, Nonouti, Aranuka, Maiana, Abemama, Kuria, Tarawa, Marakei, Butaritari, and Makin, before returning to Oahu on June 13. The Peacock and Flying Fish then left for the Columbia River on June 21.
In April 1841, USS Peacock, under Lieutenant William L. Hudson, and USS Flying Fish, surveyed Drummond's Island, which was named for an American of the expedition. Lieutenant Hudson heard from a member of his crew that a ship had wrecked off the island and her crew massacred by the Gilbertese. A woman and her child were said to be the only survivors, so Hudson decided to land a small force of marines and sailors, under William M. Walker, to search the island. Initially, the natives were peaceful and the Americans were able to explore the island, without results. It was when the party was returning to their ship that Hudson noticed a member of his crew was missing.
After making another search, the man was not found and the natives began arming themselves. Lieutenant Walker returned his force to the ship, to converse with Hudson, who ordered Walker to return to shore and demand the return of the sailor. Walker then reboarded his boats with his landing party and headed to shore. Walker shouted his demand and the natives charged for him, forcing the boats to turn back to the ships. It was decided on the next day that the Americans would bombard the hostiles and land again. While doing this, a force of around 700 Gilbertese warriors opposed the American assault, but were defeated after a long battle. No Americans were hurt, but twelve natives were killed and others were wounded, and two villages were also destroyed. A similar episode occurred two months before in February when the Peacock and the Flying Fish briefly bombarded the island of Upolu, Samoa following the death of an American merchant sailor on the island.
The Vincennes and Porpoise reached Cape Disappointment on April 28, 1841, but then headed north to the Strait of Juan de Fuca, Port Discovery, and Fort Nisqually, where they were welcomed by William Henry McNeill and Alexander Caulfield Anderson. The Porpoise surveyed the Admiralty Inlet, while boats from the Vincennes surveyed Hood Canal, and the coast northwards to the Fraser River. Wilkes visited Fort Clatsop, John McLoughlin at Fort Vancouver, and William Cannon on the Willamette River, while he sent Lt. Johnson on an expedition to Fort Okanogan, Fort Colvile and Fort Nez Perces, where they met Marcus Whitman. Like his predecessor, British explorer George Vancouver, Wilkes spent a good deal of time near Bainbridge Island. He noted the bird-like shape of the harbor at Winslow and named it Eagle Harbor. Continuing his fascination with bird names, he named Bill Point and Wing Point. Port Madison, Washington and Points Monroe and Jefferson were named in honor of former United States presidents. Port Ludlow was assigned to honor Lieutenant Augustus Ludlow, who lost his life during the War of 1812.
The Peacock and Flying Fish arrived off Cape Disappointment on July 17. However, the Peacock went aground while attempting to enter the Columbia River and was soon lost, though with no loss of life. The crew was able to lower six boats and get everyone into Baker's Bay, along with their journals, surveys, the chronometers, and some of Agate's sketches. A one-eyed Indian named George then guided the Flying Fish into the same bay.
There, the crew set up "Peacockville", assisted by James Birnie of the Hudson's Bay Company, and the American Methodist Mission at Point Adams. They also traded with the local Clatsop and Chinookan Indians over the next three weeks, while surveying the channel, before journeying to Fort George and a reunion with the rest of the squadron. This prompted Wilkes to send the Vincennes to San Francisco Bay, while he continued to survey Grays Harbor.
From the area of modern-day Portland, Wilkes sent an overland party of 39 southwards, led by Emmons, but guided by Joseph Meek. The group included Agate, Eld, Colvocoresses, Brackenridge, Rich, Peale, Stearns, and Dana, and proceeded along an inland route to Fort Umpqua, Mount Shasta, the Sacramento River, John Sutter's New Helvetia, and then onwards to San Francisco Bay. They departed September 7, and arrived aboard the Vincennes in Sausalito on October 23, having traveled along the Siskiyou Trail.
Wilkes arrived with the Porpoise and Oregon, while the Flying Fish was to rendezvous with the squadron in Honolulu. The squadron surveyed San Francisco and its tributaries, and later produced a map of "Upper California". The expedition then headed back out on October 31, arriving Honolulu on November 17, and departing on November 28. They included a visit to Wake Island, and returned by way of the Philippines, Borneo, Singapore, Polynesia, and the Cape of Good Hope, reaching New York on June 10, 1842.
The expedition was plagued by poor relationships between Wilkes and his subordinate officers throughout. Wilkes' self-proclaimed status as captain and commodore, accompanied by the flying of the requisite pennant and the wearing of a captain's uniform while being commissioned only as a Lieutenant, rankled heavily with other members of the expedition of similar real rank. His apparent mistreatment of many of his subordinates, and indulgence in punishments such as "flogging round the fleet" resulted in a major controversy on his return to America. Wilkes was court-martialled on his return, but was acquitted on all charges except that of illegally punishing men in his squadron.
Significance
The Wilkes Expedition played a major role in the development of 19th-century science, particularly in the growth of the American scientific establishment. Many of the species and other items found by the expedition helped form the basis of collections at the new Smithsonian Institution.
With the help of the expedition's scientists, derisively called "clam diggers" and "bug catchers" by navy crew members, 280 islands, mostly in the Pacific, were explored, and over of Oregon were mapped. Of no less importance, over 60,000 plant and bird specimens were collected. A staggering amount of data and specimens were collected during the expedition, including the seeds of 648 species, which were later traded, planted, and sent throughout the country. Dried specimens were sent to the National Herbarium, now a part of the Smithsonian Institution. There were also 254 live plants, which mostly came from the home stretch of the journey, that were placed in a newly constructed greenhouse in 1850, which later became the United States Botanic Garden.
Alfred Thomas Agate, an engraver and illustrator, created an enduring record of traditional cultures such as the illustrations made of the dress and tattoo patterns of natives in the Ellice Islands in present-day Tuvalu.
A collection of artifacts from the expedition also went to the National Institute for the Promotion of Science, a precursor of the Smithsonian Institution. These joined artifacts from American history as the first artifacts in the Smithsonian collection.
Published works
For a short time Wilkes was attached to the Office of Coast Survey, but from 1844 to 1861 he was chiefly engaged in preparing the expedition report. Twenty-eight volumes were planned, but only nineteen were published. Of these, Wilkes wrote the multi-volume Narrative of the United States exploring expedition, during 1838, 1839, 1840, 1841, 1842, Hydrography, and Meteorology.
The Narrative concerns the customs, political and economic conditions of many places then little-known. Other contributions were three reports by James Dwight Dana on Zoophytes, Geology, and Crustacea. In addition to shorter articles and reports, Wilkes published Western America, including California and Oregon, and Theory of the Winds. The Smithsonian Institution digitized the five volume narrative and the accompanying scientific volumes. The mismanagement that plagued the expedition prior to its departure continued after its completion. By June 1848, many of the specimens had been lost or damaged and many remained unidentified. In 1848 Asa Gray was hired to work on the botanical specimens, and published the first volume of the report on botany in 1854, but Wilkes was unable to secure the funding for the second volume.
See also
European and American voyages of scientific exploration
Notes
References
Bibliography
External links
Alfred Agate Collection at Naval History and Heritage Command
US Exploring Expedition – at Smithsonian Institution Libraries Digital Collections
Video of Dr. Adrienne Kaeppler discussing the Smithsonian Institution Anthropology collections from the expedition
Charles L. Erskine's Panorama Lecture at Dartmouth College Library
1838 in the United States
1839 in Antarctica
Collection of the Smithsonian Institution
Circumnavigations
Exploration of North America
Explorers of the United States
Global expeditions
History of science and technology in the United States
Military expeditions of the United States
Oceanography
Pacific expeditions
Pacific Ocean
United States Navy in the 19th century | United States Exploring Expedition | Physics,Environmental_science | 4,041 |
59,680,063 | https://en.wikipedia.org/wiki/Human%20satellite%20II | Human satellite II is an exceptionally high-copy but unexplored sequence of the human genome thought of as junk DNA has a surprising ability to impact master regulators of our genome, and it goes awry in 50 percent of tumors.
Because HSAT-II DNA is normally methylated (a form of gene regulation), it remains dormant in healthy cells. For this reason, the HSAT-II hasn't been extensively studied and has not been thought to have a function. Due to its similarities to Human Satellite 3, the primary sequence component of the traditional human satellite fraction II (also known as Human Satellite 2 or HSat2) is sometimes incorrectly marked by RepeatMasker. In RepeatMasker annotations, both repeats frequently appear as a mixed pattern of "HSATII" and "(CATTC)n simple repeats." Based on this problem, Oxford Nanopore Technologies researcher used their own characterization of these sequences inside the CHM13 genome To further classify each HSat2 array into its previously identified subfamilies.
In fact, standard genomic experiments intentionally screen HSAT-II out of the results. Both herpes viruses and cancer manipulate this same pathway causing genetic instability and disease.
References
DNA
Gene expression
Non-coding DNA | Human satellite II | Chemistry,Biology | 255 |
14,878,999 | https://en.wikipedia.org/wiki/NOL3 | Nucleolar protein 3 is a protein that in humans is encoded by the NOL3 gene.
Nol3 has been shown to be induced in multiple cancer types and acts as a repressor of apoptosis leading to resistance and proliferation. Paradoxically, loss of Nol3 also leads to hematological disruption in mice resulting in a myeloproliferative neoplasm resembling primary myelofibrosis (PMF), and its deletion has also been detected in patient samples of PMF.
Interactions
NOL3 has been shown to interact with SFRS9 and Caspase 8.
References
Further reading | NOL3 | Chemistry | 131 |
13,485,805 | https://en.wikipedia.org/wiki/Radio-frequency%20engineering | Radio-frequency (RF) engineering is a subset of electrical engineering involving the application of transmission line, waveguide, antenna, radar, and electromagnetic field principles to the design and application of devices that produce or use signals within the radio band, the frequency range of about 20 kHz up to 300 GHz.
It is incorporated into almost everything that transmits or receives a radio wave, which includes, but is not limited to, mobile phones, radios, Wi-Fi, and two-way radios.
RF engineering is a highly specialized field that typically includes the following areas of expertise:
Design of antenna systems to provide radiative coverage of a specified geographical area by an electromagnetic field or to provide specified sensitivity to an electromagnetic field impinging on the antenna.
Design of coupling and transmission line structures to transport RF energy without radiation.
Application of circuit elements and transmission line structures in the design of oscillators, amplifiers, mixers, detectors, combiners, filters, impedance transforming networks and other devices.
Verification and measurement of performance of radio frequency devices and systems.
To produce quality results, the RF engineer needs to have an in-depth knowledge of mathematics, physics and general electronics theory as well as specialized training in areas such as wave propagation, impedance transformations, filters and microstrip printed circuit board design.
Radio electronics
Radio electronics is concerned with electronic circuits which receive or transmit radio signals.
Typically, such circuits must operate at radio frequency and power levels, which imposes special constraints on their design. These constraints increase in their importance with higher frequencies. At microwave frequencies, the reactance of signal traces becomes a crucial part of the physical layout of the circuit.
List of radio electronics topics:
RF oscillators: Phase-locked loop, voltage-controlled oscillator
Transmitters, transmission lines, transmission line tuners, RF connectors
Antennas, antenna theory
Receivers, tuners
Amplifiers
Modulators, demodulators, detectors
RF filters
RF shielding, ground plane
Direct-sequence spread spectrum (DSSS), noise power
Digital radio
RF power amplifiers
Metal–oxide–semiconductor field-effect transistor (MOSFET)s: Power MOSFET, Laterally-diffused metal-oxide semiconductor (LDMOS)
Bipolar junction transistors
Baseband processors (Complementary metal–oxide–semiconductor (CMOS))
RF CMOS (mixed-signal integrated circuits)
Duties
Radio-frequency engineers are specialists in their respective field and can take on many different roles, such as design, installation, and maintenance. Radio-frequency engineers require many years of extensive experience in the area of study. This type of engineer has experience with transmission systems, device design, and placement of antennas for optimum performance.
The RF engineer job description at a broadcast facility can include maintenance of the station's high-power broadcast transmitters and associated systems. This includes transmitter site emergency power, remote control, main transmission line and antenna adjustments, microwave radio relay STL/TSL links, and more.
In addition, a radio-frequency design engineer must be able to understand electronic hardware design, circuit board material, antenna radiation, and the effect of interfering frequencies that prevent optimum performance within the piece of equipment being developed.
Mathematics
There are many applications of electromagnetic theory to radio-frequency engineering, using conceptual tools such as vector calculus and complex analysis. Topics studied in this area include waveguides and transmission lines, the behavior of radio antennas, and the propagation of radio waves through the Earth's atmosphere. Historically, the subject played a significant role in the development of nonlinear dynamics.
See also
Broadcast engineering
Information theory
Microwave engineering
Overlap zone
Radar engineering
Radio resource management
Radio-frequency current
SPLAT! (software)
List of textbooks in electromagnetism
References
External links
Practical Guide to Radio-Frequency Analysis and Design
Radio spectrum
Radio waves
Radio waves
Electromagnetic spectrum
Broadcast engineering
Electrical engineering
Electronic engineering
Broadcasting occupations
Engineering occupations
MOSFETs
Telecommunications techniques | Radio-frequency engineering | Physics,Technology,Engineering | 786 |
43,825,969 | https://en.wikipedia.org/wiki/Total%20set | In functional analysis, a total set (also called a complete set) in a vector space is a set of linear functionals with the property that if a vector satisfies for all then is the zero vector.
In a more general setting, a subset of a topological vector space is a total set or fundamental set if the linear span of is dense in
See also
References
Linear algebra
Topological vector spaces | Total set | Mathematics | 81 |
2,226,665 | https://en.wikipedia.org/wiki/Outside%20broadcasting | Outside broadcasting (OB) is the electronic field production (EFP) of television or radio programmes (typically to cover television news and sports television events) from a mobile remote broadcast television studio. Professional video camera and microphone signals come into the production truck for processing, recording and possibly transmission.
Some outside broadcasts use a mobile production control room (PCR) inside a production truck.
History
Outside radio broadcasts have been taking place since the early 1920s and television ones since the late 1920s. The first outside broadcast by the British Broadcasting Company was of the British National Opera Company production of The Magic Flute from the Royal Opera House, Covent Garden on 8 January, 1923. The first large-scale outside broadcast was the televising of the Coronation of George VI and Elizabeth in May 1937, done by the BBC's first Outside Broadcast truck, MCR 1 (short for Mobile Control Room).
After the Second World War, the first notable outside broadcast was of the 1948 Summer Olympics. The Coronation of Elizabeth II followed in 1953, with 21 cameras being used to cover the event.
In December 1963 instant replays were used for the first time. Director Tony Verna used the technique on the Army-Navy game which aired on CBS Sports on December 7, 1963.
The 1968 Summer Olympics was the first with competitions televised in colour. The 1972 Olympic Games were the first where all competitions were captured by outside broadcast cameras.
During the 1970s, ITV franchise holder Southern Television was unique in having an outside broadcast boat, named Southener.
The wedding of Prince Charles and Lady Diana Spencer in July 1981 was the biggest outside broadcast at the time, with an estimated 750 million viewers.
New technology
In 2008, the first 3D outside broadcast took place with the transmission of a Calcutta Cup rugby match, but only to an audience of industry professionals who had been invited by BBC Sport.
In March 2010, the first public 3D outside broadcast took place with an NHL game between the New York Rangers and New York Islanders.
The first commercial ultra-high definition outside broadcast was a Premier League game between Stoke City v West Ham, televised by Sky Sports in August 2013.
Tests in 8K resolution outside broadcasts began to take place during the 2010s, including tests by NHK and BT Sport. The first public 8K outside broadcast in the UK took place in February 2020.
Modern applications
Modern outside broadcasts now use specially designed OB vehicles, many of which are now built based around IP technology rather than relying on coaxial cable.
There has been an increasing rise in the use of flyaway or flypack Portable Production Units, which allow for an increased level of customisation and can be rigged in a larger variety of venues.
In the past many outside broadcasting applications have relied on using satellite uplinks to broadcast live audio and video back to the studio. While this has its advantages such as the ability to set up anywhere covered by the respective geostationary satellite, satellite uplinking is relatively expensive and the round trip latency is in the range of 240 to 280 milliseconds.
As more venues install fiber optic cable, this is increasingly used. For news gathering, contribution over public internet is also now used. Modern applications such as hardware and software IP codecs have allowed the use of public 3G/4G networks to broadcast video and audio. The latency of 3G is around 100–500 ms, while 4G is less than 100 ms.
Gallery
See also
Production truck
Satellite truck
Electronic news-gathering (ENG)
References
External links
Recreation of a full 1970s BBC Outside Broadcast production
Technical planning stage of a 1970s Outside Broadcast production
Demonstration of the 'lining up' process for EMI 2001 OB camera from the 1970s
Discussion and demonstration of the microphone and communications set up for a sports OB
BBC Outside Broadcast crew reflect on their careers in OB production
TV Outside Broadcast History Website
Broadcast engineering
Television terminology
fr:Régie (spectacle)#Télévision | Outside broadcasting | Engineering | 779 |
47,198,640 | https://en.wikipedia.org/wiki/Crowther%20criterion | The conventional method to evaluate the resolution of a tomography reconstruction is determined by the Crowther criterion.
The minimum number of views, m, to reconstruct a particle of diameter D to a resolution of d (=1/R) is given by
References
Condensed matter physics
Electron microscopy
Medical imaging
Geometric measurement
X-ray computed tomography
Multidimensional signal processing | Crowther criterion | Physics,Chemistry,Materials_science,Mathematics,Engineering | 75 |
25,068,575 | https://en.wikipedia.org/wiki/Wellcome%E2%80%93MRC%20Cambridge%20Stem%20Cell%20Institute | The Cambridge Stem Cell Institute at the University of Cambridge is a research centre for the nature and potential medical uses of stem cells. It is located on the Cambridge Biomedical Campus in Cambridge, England and was originally funded by the Wellcome Trust and the Medical Research Council.
The main areas of study include pluripotent and neural stem cells, as well as epidermal stem cells. Key advances in stem cell science at the centre include the elucidation of the role of the nanog protein in pluripotency and work on inhibiting cellular differentiation. It also conducts human embryo work as approved by the Human Fertilisation and Embryology Authority.
References
External links
Cambridge Stem Cell Institute
Health in Cambridgeshire
Stem Cell Institute, Cambridge
Medical research institutes in the United Kingdom
Research institutes in Cambridge
Science and technology in Cambridgeshire
Stem cell research
Wellcome Trust | Wellcome–MRC Cambridge Stem Cell Institute | Chemistry,Biology | 173 |
37,900,823 | https://en.wikipedia.org/wiki/Domino%20Sugar%20Refinery | The Domino Sugar Refinery is a mixed-use development and former sugar refinery in the neighborhood of Williamsburg in Brooklyn, New York City, along the East River. When active as a refinery, it was operated by the Havemeyer family's American Sugar Refining Company, which produced Domino brand sugar and was one of several sugar factories on the East River in northern Brooklyn.
The family's first refinery in Williamsburg opened in 1856 and was operated by Frederick C. Havemeyer Jr., the son of American Sugar's founder. After a fire destroyed the original structures, the current complex was built in 1882 by Theodore A. Havemeyer, Thomas Winslow, and J. E. James. The American Sugar Refining Company grew to control most of the sugar industry in the United States by the late 19th century, with the Brooklyn refinery as its largest plant. Many different types of sugar were refined at the facility, and it employed up to 4,500 workers at its peak in 1919. Demand started to decline in the 1920s with advances in sugar refining and the construction of other facilities, but the refinery continued to operate until 2004.
In the early 21st century, the refinery was redeveloped as office space, residential towers, and parkland. The complex's filter, pan, and finishing house was made a New York City designated landmark in 2007, because of its historical significance as one of several industrial concerns on Brooklyn's waterfront. After the failure of an initial redevelopment proposal by CPC Resources, SHoP Architects proposed another design in 2013, which was approved the next year. Demolition of the non-landmark structures in the refinery began shortly afterward, and the first new tower in the development project opened in 2017. , the refinery redevelopment consists of four completed towers; the Filter, Pan, and Finishing House; and a waterside park called Domino Park.
Refinery
The industrial waterfront of Brooklyn was developed in the 19th century with the construction of major shipping hubs such as Red Hook's Atlantic Basin, the Brooklyn Navy Yard, and Industry City. The village of Williamsburgh in northern Brooklyn was incorporated on the bank of the East River in 1827, with most of the commercial enterprises located on the waterfront, and after becoming a part of the city of Brooklyn in 1855, Williamsburg grew quickly.
German-born cousins Frederick C. Havemeyer and William Havemeyer, of the Havemeyer family, had established their first sugar refinery on Vandam Street in modern-day Hudson Square, Manhattan, in 1807. The original refinery occupied a lot of , but by the 1840s it had expanded to ten stories and occupied the whole city block. Frederick C. Havemeyer Jr. (1807–1891), who joined the Havemeyer family business in 1823, helped the operation grow into a large sugar-refining corporation.
Original facility
The Havemeyer family's sugar-refining operations had outgrown its Manhattan plant by the mid-19th century. The first member of the Havemeyer family to open a facility in Williamsburg was John C. Havemeyer, Frederick Jr.'s nephew. At the end of 1856, John C. Havemeyer and Charles E. Bertrand co-founded Havemeyer & Bertrand at the intersection of modern-day Kent Avenue and South 3rd Street. The firm assumed the name Havemeyer, Townsend & Company in 1858, then Havemeyers & Elder in 1863. The refinery employed several Havemeyer family members, including Theodore, Henry, Hector, and Charles, the latter two of whom later formed their own refinery. The Havemeyers & Elder refinery, also called the Yellow Sugar House, was the largest of the Havemeyer family plants. According to sketches, the complex included a five-story building, two single-story buildings, and a standalone chimney. During 1863 and 1865, the Havemeyers bought two lots between South 2nd and South 4th streets for expansion of the facility.
Several other refineries were subsequently built in Williamsburg, making it into the world's largest sugar-refining center at that time. By 1870, the neighborhood produced a majority of sugar used within the United States, and by 1881, the Havemeyer refinery processed about three-fourths of all refined sugar in the nation. Because of the depth of the East River in the vicinity of the refinery, shipments of raw sugar from overseas could be loaded directly into the facility. In February 1881, Havemeyers & Elder received a permit from the City of Brooklyn's Bureau of Buildings to add three stories to an existing six-story building on Kent Avenue between South 4th and South 5th streets. That November, Havemeyers & Elder acquired an adjacent parcel, which had previously been leased to rival refiners Wintjen, Dick and Harms. The same month, Theodore Havemeyer submitted plans for a ten-story brick structure, likely a new filter house, to the Bureau of Buildings.
Reconstruction
Construction on the new filter house was underway when the original refinery burned down on January 8, 1882, destroying the structures between South 3rd and South 4th streets. The fire destroyed several warehouses as well as the building that contained the refinery and finishing house. It caused an estimated $1.5 million in damage, though insurance policies covered about half of the losses, and resulted in the elimination of 1,200 to 2,000 jobs. Its destruction resulted in an increase in sugar prices nationwide.
In February 1882, Theodore Havemeyer purchased a refinery in Red Hook, Brooklyn, so that operations could restart while the new refinery was being erected. The next month, Havemeyers & Elder submitted plans for a new fireproof pan and finishing house measuring to the Bureau of Buildings. According to the Brooklyn Daily Eagle, Theodore Havemeyer supervised the new structures' construction. Two people were variously cited as being the contractor: a building application in November 1881 mentions Thomas Winslow and J. E. James as the builders, while a subsequent application in March 1882 states that Havemeyer and James were co-architects. The rebuilding was funded in part by insurance money and the sale of assets. The reconstruction was reported to be completed by July 1883. In total, work cost $7 million (equal to $ million in ).
Operations
The new refinery structure gave the Havemeyer family a large competitive advantage due to its size, and by 1884, the rebuilt plant employed 1,000 men who made 5,000 barrels of sugar daily. The family created the Sugar Refineries Company or Sugar Trust in late 1887. The Sugar Trust was reorganized into the American Sugar Refining Company in 1891 after the previous year's passage of the Sherman Antitrust Act; prior to reorganization, the trust had controlled 98% of the United States' sugar production. An account of the plant's operation in 1894 stated that the plant was "the largest of its kind in the world" with seven buildings on of land; the refinery employed 3,000 workers and utilized of coal a day, producing 13,000 barrels of sugar daily. In 1896, American Sugar became one of the original twelve companies in the Dow Jones Industrial Average. The company continued to prosper despite further antitrust legislation, and Frederick's son Henry O. Havemeyer renamed the company "Domino's Sugar" in the early 1900s.
Many different types of sugar were refined at the facility. Raw sugar was shipped from forty countries and from Florida. Raw sugar was first unloaded from piers along the East River, and mixed with water within the filter house. Then, the mixture was strained, pumped to the thirteenth floor, and placed into , circular vats called "blow-ups". Fifty pipes transported the mixture upward. Afterward, the mixture was filtered through "bone black" and canvas layers into circular tanks that measured tall and across. The solution then went into the pan house, where it was boiled at in vacuum pans that measured tall and across. Subsequently, the mixture was sent through centrifuges, where it was separated into sugar and molasses. The sugar grains were then taken to the finishing house, where they were separated in granulating machines and then roasted and dried. The roasting and drying process produced either retail-ready products such as cubes, tablets, and syrups, or individual grains that could be used as ingredients in other processes. The sugar products were packed into barrels, which were stored in the warehouses nearby.
The work conditions at the refinery were described as onerous, and the workers were poorly paid, despite working shifts of at least ten hours per day. When the refinery was founded, almost all of the workers were German immigrants, while Irish immigrants were hired as outdoor laborers. Later immigrants came from eastern, northern, and southern Europe, as well as the West Indies. Workers were paid a starting salary of between $1.12 and $1.50 per day (equivalent to between $ and $ in ), with 5- or 10-cent pay increases according to tenure. The highest-paid workers at the plant earned between $100 and $150 a month (equivalent to between $ and $ in ). According to a 1900 Brooklyn Daily Eagle article, workers were employed for at least eight years on average, and many workers either lived near Kent Avenue or took trolley lines to the refinery. Most laborers at that time lived in boarding houses, though the refinery did have lockers and showers in its basement. Workers were prone to being fired at times of job insecurity, although conditions improved in the early 20th century, when wages were increased and some workers received pensions. Most employees were men, but by 1920, about one of ten workers were women.
Later usage
Early 20th century
American Sugar established the East River Terminal Railroad in 1907 to transport sugar between the refinery and the Brooklyn Eastern District Terminal, immediately to the north of the sugar refinery. American Sugar believed the refinery to be so fireproof that it did not need insurance. In 1917, during World War I, an explosion destroyed part of the plant, killing between six and twelve workers. A crowd of more than 15,000 people gathered to watch the plant burn. Initially, there was serious concern that the explosion was the work of German agents, because the Germans were the United States' adversary in the war, but the ultimate cause was found to be the ignition of sugar grains in the refinery's machinery.
By 1919, the refinery had over 4,500 paid employees. The company took ownership of a pier at the end of Grand Street, one block north of the refinery, the same year. American Sugar also proposed closing the five short dead-end streets between Grand and South Fifth streets, in order to have full control of the land that comprised the refinery, but withdrew its application following local opposition. American Sugar proposed closing the five streets again in 1923, but this was also opposed by the local population. The company then threatened to move to New Jersey in 1924 over the failure to close the dead-end streets. At the time, the plant had an annual payroll of $3.5 million and manufactured of sugar per year. The New York City government allowed the company to close streets in front of the refinery.
In 1926, American Sugar commenced a large renovation of the plant. As part of the project, the dock was replaced with a bulkhead, and a new boiler house was erected, as well as a warehouse that could store of sugar. The renovation was completed in 1927. The upgrades had cost $3 million and resulted in increased efficiency in the refinery's operations. Around this time, a large sign with yellow letters spelling "Domino Sugar" was erected on one of the refinery's buildings, facing the East River. By American Sugar's 50th anniversary in 1941, the refinery produced 60 grades of sugars and was a significant source of income to the municipal governments and surrounding community. It was estimated that from 1912 to 1941, the factory paid $156 million in wages, $4 million in taxes, and $2 million for water; accepted sugar from 2,252 ships; and used of coal and 17,537 barrels of oil. The Brooklyn Citizen said in 1941 that the refinery made Brooklyn the center of sugar refining in the United States, similar to how Detroit manufactured cars and Pittsburgh manufactured steel.
Decline
As early as the 1920s, industry-wide changes were resulting in a reduction of utilization of the Brooklyn plant. After American Sugar completed a plant in Baltimore in 1922, refining operations in Brooklyn were reduced. The company also assumed space at 120 Wall Street in Manhattan's Financial District in 1930, using that space for its offices. The refinery's cooperage closed in 1946 after the industry stopped using wood barrels to ship sugar. Employment at the plant fell after the end of World War II in 1945; the company had 1,500 workers in 1959. Research and development activities were relocated in 1958 to American Sugar's Philadelphia facility. Despite this, the company spent $16 million on expanding the facility in the 1960s. American Sugar was renamed Amstar in 1970, and its New York City office was relocated to 1251 Avenue of the Americas in 1971. By the late 1970s, the Amstar refinery was the only remaining sugar refinery on the Williamsburg waterfront.
The Amstar brand was purchased by British firm Tate & Lyle in 1988. Three years later, Amstar became known as Domino Sugar, after its primary trademark. Employment at the Domino Sugar Refinery continued to decrease, and by 1996 the plant had only 450 workers. After union workers' contracts expired in late 1998, Tate & Lyle announced upgrades to the refinery that would eliminate 100 jobs and weaken union guarantees. As a result, 284 workers went on strike in June 1999. When the strike started, Domino reduced operations at the refinery, performing much of the refining at its Baltimore plant before shipping it to Brooklyn for finishing. The strike ended in February 2001, making it one of the longest-ever in the city's history. Although over a hundred workers defected and returned to work, the remaining striking workers agreed to Tate & Lyle's plan to eliminate 110 positions. American Sugar Refining bought the brand and plant from Tate & Lyle the same year.
Though the complex was able to process of sugar a year, it was only processing half that amount by 2002. The next year, American Sugar Refining announced that the Domino Sugar plant would be shuttered due to a lack of demand. The refinery stopped operating in 2004. More than 220 workers were laid off at the end of January 2004, and two dozen workers were retained for packing operations that shuttered by the end of the year.
Redevelopment plans
CPC proposal
The site was purchased by CPC Resources, the for-profit arm of the Community Preservation Corporation, and Brooklyn developer Isaac Katan in July 2004 for $55.8 million. Following a wide-ranging rezoning of the north Brooklyn waterfront the next year, preservationists lobbied to save the Domino Sugar Refinery and other industrial structures on the waterfront. The Landmarks Preservation Commission (LPC) designated the Pan, Filter, and Finishing House as an official city landmark in 2007. Though the yellow "Domino Sugar" sign facing the East River was not part of the designation, the developer proposed keeping the sign by displaying it on top of the Pan, Filter, and Finishing House.
CPC's original plan for the site, designed by Rafael Viñoly, included up to nine buildings, four of which would be over tall. The plan called for 2,200 apartments, 660 of which would be set aside or designated as affordable housing, as well as a school; the "Domino Sugar" sign on the refinery would be preserved. The CPC plan received support from the New York City Council in 2010. However, it faced opposition from local residents, who objected to the scale of the proposed development. In 2012, CPC defaulted on its development project for the Domino Sugar Factory. Development company Two Trees Management expressed interest for the site that June and purchased it for $185 million that October.
SHoP proposal
Two Trees submitted a new design plan for the site in 2013, designed by SHoP Architects. The new plan called for 60% more public open space on a new street grid, allowed mixed-use zoning, and was designed to connect the existing neighborhood to the new waterfront. Two Trees' plan would still set aside 660 out of the 2,200 apartments for affordable housing, but it would also include buildings of up to 50 stories, which would be some of Brooklyn's tallest buildings. Though some neighborhood residents opposed the redevelopment, this opposition was more limited after Two Trees agreed to add more affordable housing and parkland. One of the proposed buildings was replaced within a plaza. The revised plan faced objection from New York City mayor Bill de Blasio, who wanted even more affordable housing on the site. In response, David Walentas indicated that he was willing to revert to the older plan.
In March 2014, the City Planning Commission approved the new plans, which would have cost $1.5 billion, after Two Trees Management agreed to include more affordable housing units. That deal required Two Trees to include 700 below-market-rate units, which was 40 more than what was originally offered and 260 more than what the CPC wanted. In exchange, Two Trees was allowed to build its towers of up to 55 stories. Three floors would be built on top of the existing factory building.
Redevelopment progress
In 2014, photographer David Allee explored the abandoned portions of the refinery, stating that it smelled of "creme brulee mixed with mold and rot". The same year, from May through July, artist Kara Walker exhibited her piece A Subtlety at the refinery's Syrup Shed. After the closure of the exhibition, the non-landmarked portions of the refinery were to be demolished, as had been planned before the show. In mid-2014, demolition of the structures commenced; demolition was mostly complete by December 2014. Excavation for the first building in the complex, 325 Kent Avenue, started in May 2015. Two Trees also cleaned out the Pan, Filter, and Finishing House, which still contained its old sugar-refining machinery. In February 2017, the developers of the redevelopment project opened a housing lottery for the 104 affordable-housing apartments at 325 Kent Avenue, which attracted 87,000 applicants, or about 837 for every apartment. 325 Kent Avenue opened in July 2017, and the first residents moved into the building the next month.
A second residential building, 260 Kent Avenue, started construction in early 2018. The LPC approved a redesign for the landmarked portion of the refinery complex in November 2017. Domino Park, a public park along the East River waterfront, opened in June 2018. A modification to the landmarked Pan, Filter, and Finishing House was approved in August 2019. The interconnected towers at One South First and Ten Grand opened shortly afterward. One South First opened in September 2019, followed by Ten Grand that November. The first office tenant at Ten Grand signed a lease in December 2019. No other office tenants had signed leases at Ten Grand before the onset of the COVID-19 pandemic in New York City in early 2020, which caused demand for physical office space to decline significantly. During the pandemic, Two Trees leased space at Ten Grand to numerous local companies. According to a 2022 analysis by Curbed, "85 percent of the founders and principals" of the companies at Ten Grand lived in either Williamsburg or the adjacent neighborhoods of Greenpoint and Bushwick.
By early 2021, the Pan, Filter, and Finishing House, which had been renamed the Refinery, was being renovated. Two Trees opened an affordable-housing lottery for One South First's 89 affordable units in early 2022. That August, M&T Bank gave Two Trees an $80 million construction loan to fund the completion of the development. Around the same time, Two Trees began leasing out of office space in the Refinery building. Work on 346 Kent Avenue (later known as One Domino Square), a pair of towers at the southern end of the development, began in November 2022. To finance the construction of 346 Kent Avenue, Two Trees received a $365 million loan from JPMorgan Chase at the end of that year. In addition, the Refinery building's barrel-vaulted roof was being completed by late 2022, and an LED replica of the old "Domino Sugar" sign was installed on the building that December.
The Refinery building reopened September 27, 2023. Two Trees offered tax breaks to companies that relocated from Manhattan to the Refinery building. Sales at One Domino Square began in April 2024, and the building formally opened in June of that year. The Domino Square plaza opened at the Domino Sugar Refinery site in September 2024. Between 15 and 20 percent of One Domino Square's condos had been sold by late 2024, but only 25% of the Refinery building's space had been leased out.
Buildings
The Domino Sugar Refinery site spans on the East River north of the Williamsburg Bridge. When the redevelopment is complete, it will include of community and commercial space; of office space; 2,800 apartments, of which 700 will be affordable; and of parkland on the waterfront, which is part of Domino Park. The entire complex will eventually contain five residential buildings and cost $3 billion.
Residential and commercial towers
325 Kent Avenue
325 Kent Avenue, a 16-story, tower designed by SHoP Architects, is located on the east side of Kent Avenue. The building contains 522 residential units, 105 of which are affordable-housing apartments, and the units range from studio apartments to two-bedroom apartments. 325 Kent Avenue has of residential space and of ground-floor retail space. The building contains amenities such as a rooftop deck, a fitness center, a residents' lounge, and a courtyard on the fourth floor.
The lower portion of the facade is made of copper, while the upper portion consists of zinc. The massing of the structure consists of two stepped towers on the north and south, which step down gradually from west to east. The tops of the two wings are connected on the western side of the building, creating a rectangular hole on the western facade and giving it a "doughnut" shape.
One South First and Ten Grand
The 45-story One South First tower (also known as 260 Kent Avenue) and the 24-story Ten Grand tower are located between South 1st and South 2nd streets, north of the Pan, Filter, and Finishing House on the western side of Kent Avenue. The structures were designed by Cookfox. One South First contains 330 residential units, 66 of which are affordable-housing apartments; the units range from studios to two-bedroom apartments. Ten Grand contains of retail space and of office space. The combined structure's amenities include a rooftop deck with cabanas, a fitness center, a residents' lounge, a swimming pool, and spaces for coworking.
The buildings comprise a single structure; the massing is designed so that the upper stories of One South First are carried over the top of Ten Grand upon a glass-clad structure. The facade is made of precast concrete, which the architects stated is based on sugar crystals' molecular structure. The panels for One South First generally measure , while the panels for Ten Grand and the shared base measure .
One Domino Square
One Domino Square, at 5 South Fifth Street, is composed of two towers rising from a shared base. It was designed by Annabelle Selldorf and includes 160 condominiums and about 400 rental apartments. About 120 of the rental apartments are affordable housing units and are reserved for low-income residents. The condo tower is 39 stories tall and is the Domino Sugar Refinery complex's only condo tower, while the rental tower is 55 stories tall. The facade of both towers is made of iridescent porcelain tiles.
The two towers combined have over of space. The podium includes retail on the ground story. There are of amenity space on five additional floors, including terraces, a fitness center, coworking space, and a spa. An elliptical staircase connects three of the amenity floors. The condos range from one to three bedrooms and contain features such as movable windows, rooms with high ceilings, and smart devices in the kitchens and bathrooms.
Parks
Domino Park runs along the East River waterfront, west of Kent Avenue. Designed by the architectural firm of James Corner, the public park includes pieces of machinery from the factory, as well as gardens, a play area for children, and various fields. An elevated walkway runs along the length of the park. River Street runs parallel to the park for the entire length of the development.
Just south of the refinery building, and next to Domino Park, is Domino Square, a public plaza. It was designed by Field Operations and Studio Cadena, with Lisa Switkin as the landscape architect. Domino Square is shaped like an oval bowl, which, at its widest point, measures across. There are 120 plantings, as well as several levels of seating. The plantings include pines, oaks, redbud trees, and flowers within steel planters; Switkin said these plantings were meant to allude to a forest in the northeastern United States. The plaza itself is paved in asphalt, and there is a reclaimed water system underneath the plaza, which treats recycled water from the complex's buildings. The interior of the bowl can be used as a theater in the round, an event space, or a wintertime ice rink. Around the plaza are retail spaces.
Refinery
When the refinery was rebuilt in 1882–1883, it was composed of several structures on the west side of Kent Avenue between South 2nd and South 6th streets. It was described upon its completion as being the largest sugar refinery in the Americas. The Pan, Filter, and Finishing House is located between South 2nd and South 3rd streets. Immediately adjacent, between South 3rd and South 4th streets, was a 6-story storehouse and a machine shop. The block between South 4th and South 5th streets was a 7-story refinery building, while the block to the south was a single-story detached storehouse. Only the Pan, Filter, and Finishing House remains of the refinery complex.
Pan, Filter, and Finishing House
The extant structure of the refinery consists of the Pan, Filter, and Finishing House (also known as the Refinery building), a New York City designated landmark designed by Theodore Havemeyer, Thomas Winslow, and J. E. James. The building is at 292 Kent Avenue between South 2nd and South 3rd streets.
Form and facade
The 10-story pan house and Finishing House sections are tall, while the 13-story filter house section is tall, including a chimney. These structures are interconnected and measured north–south by west–east. The Pan, Filter, and Finishing House was one of the tallest buildings in Brooklyn when finished, rivaling the heights of early skyscrapers in Lower Manhattan's Financial District.
The Pan, Filter, and Finishing House is made mostly of reddish brick, which are thick on the lower stories and thick on the upper stories. The massing has no setbacks, though the facade has decorative elements on the upper stories. On the eastern facade, along Kent Avenue, there are vertical brick pilasters. On the western facade, facing the East River, the facade contains bricks that are recessed to form patterns such as chevrons and polygons. In some places, bluestone was used in belt courses and keystones. Most of the windows have brick arches. The building was fueled by coal, which required a chimney to ventilate safely. The chimney was among the region's tallest when the Pan, Filter, and Finishing House was built. The top section of the chimney was expanded in the 1920s using curved brick. To deliver coal to the refinery, American Sugar used ten coal barges, each with a capacity of between .
Vishaan Chakrabarti of Practice for Architecture and Urbanism designed a conversion of the building in 2017. The plans include adding a new glass facade with a barrel vault behind the existing, landmarked walls of the Pan, Filter, and Finishing House. The glass roof was originally proposed to be high, but plans for the structure were modified in 2019, calling for a glass roof tall. The new structure rises 15 stories to the barrel vault, and a penthouse measuring tall is placed immediately below the vault. The shape of the roof was inspired by the arched window openings that are placed throughout the original facade. A reviewer for the Financial Times wrote in 2023 that the Refinery building was "an object from another age, a time when Brooklyn was a place of production rather than consumption".
Interior
The interior was outfitted with brick floors atop brick flat-topped arches, which were supported by iron beams and 66 cast-iron columns. Fire escapes, fire extinguishers, and electric lights were also present in the Pan, Filter, and Finishing House. The interior of the building was converted to of office space in the 2020s.
As part of the interior renovation, the ceiling heights of floors 1–4, 14, and 15 were increased, while floor 16 was eliminated. The ground floor is used for retail and also contains restrooms for Domino Park visitors. The building also has a fitness club with a gym and swimming pool. Floors 2–13 are used as office space, and floor 14 has a double-height event space with a catering kitchen and service areas. Each story covers . Above the first story, the glass office structure is recessed from the landmarked facade, and each story is high. The structure's staircases are between the landmarked facade and the glass structure. A wall garden is also placed between the new office structure and the landmarked facade. There is no usable space between the old and new facades, except at ground level where the window sills of the new facade reach the floor.
Former buildings
The former buildings at the refinery include the Syrup Shed, the Wash House, the Turbine Room, the Power House, and the Pump House. Several gantry cranes were situated on the waterfront, unloading sugar. The cranes ran on tracks that were long.
The complex also contained a "bin structure" in which sugar grains were categorized by size, as well as conveyor bridges leading down to the refinery building. A yellow "Domino Sugar" sign, dating from the 1920s, was hung on one of the buildings facing the waterfront. In December 2022, a replica of the old sign was installed on the Pan, Filter, and Finishing House. In contrast to the original neon sign, the replica contains letters illuminated by LEDs.
A two-story boiler house was located along the East River, west of the refinery building. A warehouse was located adjacent to the boiler house. Five large pumps drew in of saltwater from the East River, which was used for the condensers and then pumped back out. The refinery also used large amounts of fresh water: in 1903, it was estimated that the refinery alone used two percent of Brooklyn's water supply.
See also
History of sugar
List of New York City Designated Landmarks in Brooklyn
References
Informational notes
Citations
Bibliography
External links
1882 establishments in New York (state)
Sugar industry of the United States
Buildings and structures in Brooklyn
Historic American Engineering Record in New York City
Industrial buildings and structures in New York City
Industrial buildings completed in 1882
Mill architecture
New York City Designated Landmarks in Brooklyn
Redevelopment projects in the United States
Sugar refineries in the United States
Williamsburg, Brooklyn | Domino Sugar Refinery | Engineering | 6,322 |
11,823,468 | https://en.wikipedia.org/wiki/Paracoccidioides%20brasiliensis | Paracoccidioides brasiliensis is a dimorphic fungus and one of the two species that cause paracoccidioidomycosis (the other being Paracoccidioides lutzii). The fungus has been affiliated with the family Ajellomycetaceae (division Ascomycota) although a sexual state or teleomorph has not yet been found.
History
Paracoccidioides brasiliensis was first discovered by Adolfo Lutz in 1908 in Brazil. Although Lutz did not suggest a name for the disease caused by this fungus, he made note of structures he called "pseudococcidica" together with mycelium in cultures grown at 25 °C. In 1912, Alfonse Splendore proposed the name Zymonema brasiliense and described the features of the fungus in culture. Finally in 1930, Floriano de Almeida created the genus Paracoccidioides to accommodate the species, noting its distinction from Coccidioides immitis.
Physiology
Paracoccidioides brasiliensis is a nonphotosynthetic eukaryote with a rigid cell wall and organelles very similar to those of higher eukaryotes. Being a dimorphic fungus, it has the ability to grow an oval yeast-like form at 37 °C and an elongated mycelial form produced at room temperature. The mycelial and yeast phases differ in their morphology, biochemistry, and ultrastructure. The yeast form contains large amounts of α-(1,3)-linked glucan. The chitin content of the mycelial form is greater than that of the yeast form, but the lipid content of both phases is comparable.
The yeast reproduces by asexual budding, where daughter cells are borne asynchronously at multiple, random positions across the cell surface. Buds begin by layers of cell wall increasing in optical density at a point that eventually gives rise to the daughter cell. Once the bud has expanded, a cleavage plane develops between the nascent cell and the mother cell. Following dehiscence, the bud scar disappears. In tissue, budding occurs inside the granulomatous center of the disease lesion, as visualized by hematoxylin and eosin (H&E) staining of histologic sections. Nonbudding cells measure 5–15 μm in diameter, whereas those with multiple spherical buds measure from 10–20 μm in diameter. In electron microscopy, cells with multiple buds have been found to have peripherally located nuclei and cytoplasm surrounding a large central vacuole. In the tissue form of P. brasiliensis, yeast cells are larger with thinner walls and a narrower bud base than those of the related dimorphic fungus, Blastomyces dermatitidis. The yeast-like form of P. brasiliensis contains multiple nuclei, a porous two-layered nuclear membrane, and a thick cell wall rich in fibers, whereas the mycelial phase has thinner cell walls with a thin, electron-dense outer layer.
Dimorphism
The mycelial form of P. brasiliensis can be converted to the yeast form in vitro by growth on brain heart infusion agar or blood-glucose-cysteine agar when incubated for 10–20 days at 37 °C. Under these conditions, hyphal cells either die or convert to transitional forms measuring 6–30 μm in diameter, which ultimately detach or remain on the hyphal cells, yielding buds. New buds develop mesosomes and become multinucleated. In contrast, yeast-like cultures can be converted to the mycelial form by reducing the incubation temperature from 37 to 25 °C. Initially, nutritional requirements of both the yeast and mycelial phases of P. brasiliensis were thought to be identical; however, later studies demonstrated the yeast form to be auxotrophic, requiring exogenous sulfur-containing amino acids including cysteine and methionine for growth.
Ecology
Although the habitat of P. brasiliensis remains unknown, it is commonly associated with soils in which coffee is cultivated. It has also been associated with the nine-banded armadillo, Dasypus novemcinctus. The disease caused by P. brasiliensis is mostly geographically restricted to Latin American countries such as Brazil, Colombia, and Venezuela, with the greatest number of cases seen in Brazil. The endemic areas are characterized by hot, humid summers, dry temperate winters, average annual temperatures between 17 and 23 °C, and annual rainfall between 500 and 800 mm. However, the precise ecology regularities of the fungus remain elusive, and P. brasiliensis has rarely been encountered in nature outside the human host. One such rare example of environmental isolation was reported in 1971 by Maria B.de Albornoz and colleagues who isolated P. brasiliensis from samples of rural soil collected in Paracotos in the state of Miranda, Venezuela. In in vitro studies, the fungus has been shown to grow when inoculated into soil and sterile horse or cow excrement. The mycelial phase has also been shown to survive longer than the yeast phase in acidic soil. Despite a sexual state not having been documented, molecular investigations suggest the existence of recombining populations of P. brasiliensis, potentially by means of an undiscovered sexual state.
The existence of a sexual cycle in P. brasiliensis, is supported by both molecular and morphological data. A comparative genome analysis with other well-studied fungi demonstrated the presence of sex-related genes in both the yeast and mycelial phases of P. brasiliensis. Also crosses of isolates of different mating types led to the formation of young ascocarps (sexual structures) with constricted coiled hyphae related to the initial stage of mating.
Epidemiology
Paracoccidioides brasiliensis causes a disease known as paracoccidioidomycosis characterized by slow, progressive granulomatous changes in the head mucosa, notably the nose and sinuses or the skin. Uncommonly, the disease affects the lymphatic system, the central nervous system, the gastrointestinal tract, or the skeletal system. Due to the high proportion of cases affecting the oral mucosa, these tissues were originally thought to be the primary route of entry of fungus. However, strong evidence now indicates the respiratory tract is the chief point of entry and P. brasiliensis lung lesions occur in nearly a third of progressive cases. The disease is not contagious.
Paracoccidioidomycosis is more frequently seen in adult males than females. The hormone estrogen is thought to inhibit the transformation of the mycelial to the yeast form, as supported by in vitro experimental data, and this factor may account for the relative resistance of women to infection.
Detection and surveillance
A number of serologic tests have been employed for the diagnosis of paracoccidioidomycosis. Double diffusion in agar gel and complement fixation test, are amongst the most commonly used tests in serodiagnosis. Culture extracts of the yeast or mycelia are exploited to produce effective, quick, and reproducible antigens. A study reported detection of 43 kD antigen in pooled sera of affected individuals, which might provide a basis for the development of a diagnostic test. Tests targeting the presence of serum antibodies to P. brasiliensis simultaneously detect both active and historical infections and cannot discriminate active infection. The evaluation of populations in endemic zones has shown roughly equal rates of seroconversion between men and women, suggesting equal rates of exposure, despite the strong male predominance shown by the clinical disease.
Clinical manifestations
Paracoccidioides brasiliensis causes mucous membrane ulceration of the mouth and nose with spread through the lymphatic system. A hypothesized portal of entry for the fungus to the body is through the periodontal membrane. The route of infection is assumed to be inhalation following which the infective propagule gives rise to the distinctive multipolar budding yeast forms in the lung resembling a "ship's wheel" seen in histological sections. Both immunologically normal and compromised people are at risk for infection.
The lungs, lymph nodes, and mucous membrane of the mouth are the most frequently infected tissues. The pathological features of paracoccidioidomycosis are similar to those seen in coccidioidomycosis and blastomycosis. However, in the former, the lesions first appear in the lymphoid tissue and then extend to mucous membranes, producing localized to diffusive tissue necrosis of the lymph nodes. The typically extensive involvement of lymphoid tissue and the limited occurrence of the gastrointestinal tract, bone and prostate set the clinical picture of paracoccidioidomycosis apart from that of blastomycosis.
References
External links
Fungi described in 1912
Onygenales
Fungal pathogens of humans
Fungus species | Paracoccidioides brasiliensis | Biology | 1,860 |
2,447,580 | https://en.wikipedia.org/wiki/Markush%20structure | A Markush structure, Markush group, or a Markush claim is a representation of alternatively useable members. Markush structures are frequently used with chemical structures to indicate a group of related chemical compounds. They are commonly used in chemistry texts and in patent claims. Markush structures are depicted with multiple independently variable groups, such as R groups in which a side chain can have varying structure. This more general depiction of the molecule, versus detailing every atom in the molecule, is used to protect intellectual property. The company which applies for a patent makes a general claim for the usage of the molecule without revealing to their competitors the exact molecule for which they are declaring a useful application.
History
Markush structures are named after Eugene A. Markush, founder of the Pharma Chemical Corporation in New Jersey. He was involved in a legal case that set a precedent for generic chemical structure patent filing, Ex parte Markush, 1925 Dec. Comm'r Pat. 126, 127 (1924). The patent filing was US Application 611,637, filed January 9, 1923. Markush was awarded a patent from the US Patent Office for “Pyrazolone Dye and Process of Making the Same” on August 26, 1924.
Use in patents
In describing a chemical, a Markush structure allows the patent-holder to list several active/effective structural formulas.
United States
In the United States, Markush structures are frequently used to claim alternative components. The correct format for a Markush structure is "closed." In other words, the claim language defined by the Markush structure requires selection from a closed group. One way of claiming a Markush structure follows the format: “a chemical selected from the group consisting of A, B, and C” where A, B, and C are alternative chemicals.
A claimed Markush structure may be improper if (1) the members of the Markush structure do not share a "single structural similarity," or (2) if the members of the Markush structure do not share a common use.
See also
Molecule editor
Chemical file format
References
External links
Chemical structures | Markush structure | Chemistry | 427 |
186,630 | https://en.wikipedia.org/wiki/Cosmic%20Background%20Explorer | The Cosmic Background Explorer (COBE ), also referred to as Explorer 66, was a NASA satellite dedicated to cosmology, which operated from 1989 to 1993. Its goals were to investigate the cosmic microwave background radiation (CMB or CMBR) of the universe and provide measurements that would help shape the understanding of the cosmos.
COBE's measurements provided two key pieces of evidence that supported the Big Bang theory of the universe: that the CMB has a near-perfect black-body spectrum, and that it has very faint anisotropies. Two of COBE's principal investigators, George F. Smoot III and John C. Mather, received the Nobel Prize in Physics in 2006 for their work on the project. According to the Nobel Prize committee, "the COBE project can also be regarded as the starting point for cosmology as a precision science".
COBE was the second cosmic microwave background satellite, following RELIKT-1, and was followed by two more advanced spacecraft: the Wilkinson Microwave Anisotropy Probe (WMAP) operated from 2001 to 2010 and the Planck spacecraft from 2009 to 2013.
Mission
The purpose of the Cosmic Background Explorer (COBE) mission was to take precise measurements of the diffuse radiation between 1 micrometre and over the whole celestial sphere. The following quantities were measured: (1) the spectrum of the 3 K radiation over the range 100 micrometres to (2) the anisotropy of this radiation from 3 to ; and, (3) the spectrum and angular distribution of diffuse infrared background radiation at wavelengths from 1 to 300 micrometres.
History
In 1974, NASA issued an Announcement of Opportunity for astronomical missions that would use a small- or medium-sized Explorer spacecraft. Out of the 121 proposals received, three dealt with studying the cosmological background radiation. Though these proposals lost out to the Infrared Astronomical Satellite (IRAS), their strength made NASA further explore the idea. In 1976, NASA formed a committee of members from each of 1974's three proposal teams to put together their ideas for such a satellite. A year later, this committee suggested a polar-orbiting satellite called COBE to be launched by either a Delta 5920-8 launch vehicle or the Space Shuttle. It would contain the following instruments:
NASA accepted the proposal provided that the costs be kept under US$30 million, excluding launcher and data analysis. Due to cost overruns in the Explorer program due to IRAS, work on constructing the satellite at Goddard Space Flight Center (GSFC) did not begin until 1981. To save costs, the infrared detectors and liquid helium dewar on COBE would be similar to those used on Infrared Astronomical Satellite (IRAS).
COBE was originally planned to be launched on a Space Shuttle mission STS-82-B in 1988 from Vandenberg Air Force Base, but the Challenger explosion delayed this plan when the Shuttles were grounded. NASA prevented COBE's engineers from going to other space companies to launch COBE, and eventually a redesigned COBE was placed into Sun-synchronous orbit on 18 November 1989 aboard a Delta launch vehicle.
On 23 April 1992, COBE scientists announced at the APS April Meeting in Washington, D.C. the finding of the "primordial seeds" (CMBE anisotropy) in data from the DMR instrument; until then the other instruments were "unable to see the template." The following day The New York Times ran the story on the front page, explaining the finding as "the first evidence revealing how an initially smooth cosmos evolved into today's panorama of stars, galaxies and gigantic clusters of galaxies."
The Nobel Prize in Physics for 2006 was jointly awarded to John C. Mather, NASA Goddard Space Flight Center, and George F. Smoot III, University of California, Berkeley, "for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation".
Spacecraft
COBE was an Explorer class satellite, with technology borrowed heavily from IRAS, but with some unique characteristics.
The need to control and measure all the sources of systematic errors required a rigorous and integrated design. COBE would have to operate for a minimum of 6 months and constrain the amount of radio interference from the ground, COBE and other satellites as well as radiative interference from the Earth, Sun and Moon. The instruments required temperature stability and to maintain gain, and a high level of cleanliness to reduce entry of stray light and thermal emission from particulates.
The need to control systematic error in the measurement of the CMB anisotropy and measuring the zodiacal cloud at different elongation angles for subsequent modeling required that the satellite rotate at a 0.8 rpm spin rate. The spin axis is also tilted back from the orbital velocity vector as a precaution against possible deposits of residual atmospheric gas on the optics as well against the infrared glow that would result from fast neutral particles hitting its surfaces at extremely high speed.
In order to meet the twin demands of slow rotation and three-axis attitude control, a sophisticated pair of yaw angular momentum wheels were employed with their axis oriented along the spin axis . These wheels were used to carry an angular momentum opposite that of the entire spacecraft in order to create a zero net angular momentum system.
The orbit would prove to be determined based on the specifics of the spacecraft's mission. The overriding considerations were the need for full sky coverage, the need to eliminate stray radiation from the instruments and the need to maintain thermal stability of the dewar and the instruments. A circular Sun-synchronous orbit satisfied all these requirements. A altitude orbit with a 99° inclination was chosen as it fit within the capabilities of either a Space Shuttle (with an auxiliary propulsion on COBE) or a Delta launch vehicle. This altitude was a good compromise between Earth's radiation and the charged particles in Earth's radiation belts at higher altitudes. An ascending node at 18:00 was chosen to allow COBE to follow the boundary between sunlight and darkness on Earth throughout the year.
The orbit combined with the spin axis made it possible to keep the Earth and the Sun continually below the plane of the shield, allowing a full sky scan every six months.
The last two important parts pertaining to the COBE mission were the dewar and Sun-Earth shield. The dewar was a superfluid helium cryostat designed to keep the FIRAS and DIRBE instruments cooled during the duration of the mission. It was based on the same design as one used on IRAS and was able to vent helium along the spin axis near the communication arrays. The conical Sun-Earth shield protected the instruments from direct solar and Earth-based radiation as well as radio interference from Earth and the COBE's transmitting antenna. Its multilayer insulating blankets provided thermal isolation for the dewar.
In January 1994, engineering operations concluded and the operation of the spacecraft was transferred to Wallops Flight Facility (WFF) for use as a test satellite.
Instruments
Differential Microwave Radiometers (DMR)
The Differential Microwave Radiometer (DMR) investigation uses three differential radiometers to map the sky at 31.4, 53, and 90 GHz. The radiometers are distributed around the outer surface of the cryostat. Each radiometer employs a pair of horn antennas viewing at 30° from the spin axis of the spacecraft, measuring the differential temperature between points in the sky separated by 60°. At each frequency, there are two channels for dual-polarization measurements for improved sensitivity and for reliability. Each radiometer is a microwave receiver whose input is switched rapidly between the two horn antennas, obtaining the difference in brightness of two fields of view 7° in diameter located 60° apart and 30° from the axis of the spacecraft. High sensitivity is achieved by temperature stabilization (at 300 K for 31.4 GHz and at 140 K for 53 and 90 GHz), by spacecraft spin, and by the ability to integrate over the entire year. Sensitivity to large-scale anisotropies is about 3E-5 K. The instrument weighs , uses 114 watts, and has a data rate of 500 bit/s.
Diffuse Infrared Background Experiment (DIRBE)
The Diffuse Infrared Background Experiment (DIRBE) consists of a cryogenically cooled (to 2 K) multiband radiometer used to investigate diffuse infrared radiation from 1 to 300 micrometres. The instrument measures the absolute flux in 10 wavelength bands with a 1° field of view pointed 30° off the spin axis. Detectors (photoconductors) and filters for the 8 to 100 micrometre channels are the same as for the IRAS mission. Bolometers are used for the longest wavelength channel (120 to 300 micrometres). The telescope is a well baffled, off-axis, Gregorian flux collector with re-imaging. The instrument weighs approximately , uses 100 W and has a data rate of 1700 bit/s.
Far Infrared Absolute Spectrophotometer (FIRAS)
The Far Infrared Absolute Spectrophotometer (FIRAS) is a cryogenically cooled polarizing Michelson interferometer used as a Fourier transform spectrometer. The instrument points along the spin axis and has a 7° field of view. This device measures the spectrum to a precision of 1/1000 of the peak flux at for each 7° field of view on the sky (over the range 0.1 to ). The FIRAS uses a special flared trumpet horn flux collector having very low sidelobe levels and an external calibrator covering the entire beam; precise temperature regulation and calibration are required. The instrument has a differential input to compare the sky with an internal reference at 3 K. This feature provides immunity from systematic errors in the spectrometer and contributes significantly to the ability to detect small deviations from a blackbody spectrum. The instrument weighs , uses 84 watts and has a data rate of 1200 bit/s.
Scientific findings
The science mission was conducted by the three instruments detailed previously: DIRBE, FIRAS and DMR. The instruments overlapped in wavelength coverage, providing consistency check on measurements in the regions of spectral overlap and assistance in discriminating signals from our galaxy, Solar System and CMB.
COBE's instruments would fulfill each of their objectives as well as making observations that would have implications outside COBE's initial scope.
Black-body curve of CMB
During the 15-year-long period between the proposal and launch of COBE, there were two significant astronomical developments:
First, in 1981, two teams of astronomers, one led by David Wilkinson of Princeton University and the other by Francesco Melchiorri of the University of Florence, simultaneously announced that they detected a quadrupole distribution of CMB using balloon-borne instruments. This finding would have been the detection of the black-body distribution of CMB that FIRAS on COBE was to measure. In particular, the Florence group claimed a detection of intermediate angular scale anisotropies at the level 100 microkelvins in agreement with later measurements made by the BOOMERanG experiment. However, a number of other experiments attempted to duplicate their results and were unable to do so.
Second, in 1987 a Japanese-American team led by Andrew E. Lange and Paul Richards of University of California, Berkeley and Toshio Matsumoto of Nagoya University made an announcement that CMB was not that of a true black body. In a sounding rocket experiment, they detected an excess brightness at 0.5 and wavelengths.
With these developments serving as a backdrop to COBE's mission, scientists eagerly awaited results from FIRAS. The results of FIRAS were startling in that they showed a perfect fit of the CMB and the theoretical curve for a black body at a temperature of 2.7 K, in contrast to the Berkeley-Nagoya results.
FIRAS measurements were made by measuring the spectral difference between a 7° patch of the sky against an internal black body. The interferometer in FIRAS covered between 2- and 95-cm−1 in two bands separated at 20-cm−1. There are two scan lengths (short and long) and two scan speeds (fast and slow) for a total of four different scan modes. The data were collected over a ten-month period.
Intrinsic anisotropy of CMB
The DMR was able to spend four years mapping the detectable anisotropy of cosmic background radiation as it was the only instrument not dependent on the dewar's supply of helium to keep it cooled. This operation was able to create full sky maps of the CMB by subtracting out galactic emissions and dipole at various frequencies. The cosmic microwave background fluctuations are extremely faint, only one part in 100,000 compared to the 2.73 K average temperature of the radiation field. The cosmic microwave background radiation is a remnant of the Big Bang and the fluctuations are the imprint of density contrast in the early universe. The density ripples are believed to have produced structure formation as observed in the universe today: clusters of galaxies and vast regions devoid of galaxies.
Detecting early galaxies
DIRBE also detected 10 new far-IR emitting galaxies in the region not surveyed by IRAS as well as nine other candidates in the weak far-IR that may be spiral galaxies. Galaxies that were detected at the 140 and 240 μm were also able to provide information on very cold dust (VCD). At these wavelengths, the mass and temperature of VCD can be derived. When these data were joined with 60 and 100 μm data taken from IRAS, it was found that the far-infrared luminosity arises from cold (≈17–22 K) dust associated with diffuse H I region cirrus clouds, 15-30% from cold (≈19 K) dust associated with molecular gas, and less than 10% from warm (≈29 K) dust in the extended low-density H II regions.
DIRBE
On top of the findings DIRBE had on galaxies, it also made two other significant contributions to science. The DIRBE instrument was able to conduct studies on interplanetary dust (IPD) and determine if its origin was from asteroid or cometary particles. The DIRBE data collected at 12, 25, 50 and 100 μm were able to conclude that grains of asteroidal origin populate the IPD bands and the smooth IPD cloud.
The second contribution DIRBE made was a model of the Galactic disk as seen edge-on from our position. According to the model, if the Sun is 8.6 kpc from the Galactic Center, then it is 15.6% above the midplane of the disk, which has a radial and vertical scale lengths of 2.64 and 0.333 kpc, respectively, and is warped in a way consistent with the HI layer. There is also no indication of a thick disk.
To create this model, the IPD had to be subtracted out of the DIRBE data. It was found that this cloud, which as seen from Earth is Zodiacal light, was not centered on the Sun, as previously thought, but on a place in space a few million kilometers away. This is due to the gravitation influence of Saturn and Jupiter.
Cosmological implications
In addition to the science results detailed in the last section, there are numerous cosmological questions left unanswered by COBE's results. A direct measurement of the extragalactic background light (EBL) can also provide important constraints on the integrated cosmological history of star formation, metal and dust production, and the conversion of starlight into infrared emissions by dust.
By looking at the results from DIRBE and FIRAS in the 140 to 5000 μm we can detect that the integrated EBL intensity is ≈16 nW/(m2·sr). This is consistent with the energy released during nucleosynthesis and constitutes about 20–50% of the total energy released in the formation of helium and metals throughout the history of the universe. Attributed only to nuclear sources, this intensity implies that more than 5–15% of the baryonic mass density implied by Big Bang nucleosynthesis analysis has been processed in stars to helium and heavier elements.
There were also significant implications into star formation. COBE observations provide important constraints on the cosmic star formation rate and help us calculate the EBL spectrum for various star formation histories. Observation made by COBE require that star formation rate at redshifts of z ≈ 1.5 to be larger than that inferred from UV-optical observations by a factor of 2. This excess stellar energy must be mainly generated by massive stars in yet - undetected dust enshrouded galaxies or extremely dusty star-forming regions in observed galaxies. The exact star formation history cannot unambiguously be resolved by COBE and further observations must be made in the future.
On 30 June 2001, NASA launched a follow-up mission to COBE led by DMR Deputy Principal Investigator Charles L. Bennett. The Wilkinson Microwave Anisotropy Probe has clarified and expanded upon COBE's accomplishments. Following WMAP, the European Space Agency's probe, Planck has continued to increase the resolution at which the background has been mapped.
See also
9997 COBE, a minor planet named after the experiment.
S150 Galactic X-Ray Mapping
Wilkinson Microwave Anisotropy Probe
References
Sources
Further reading
WMAP
External links
NASA's website on COBE
NASA informational video prior to COBE launch
COBE Mission Profile by NASA's Solar System Exploration
APOD picture of the COBE dipole, showing the 600 km/s motion of the Earth relative to the cosmic background radiation
Cosmic Background Explorer article from Scholarpedia
Satellites orbiting Earth
Cosmic microwave background experiments
Explorers Program
NASA satellites
Space telescopes
Spacecraft launched in 1989
Spacecraft launched by Delta rockets
1989 in California | Cosmic Background Explorer | Astronomy | 3,644 |
3,054,516 | https://en.wikipedia.org/wiki/Acquired%20situational%20narcissism | Acquired situational narcissism (ASN) is a form of narcissism that develops in late adolescence or adulthood, brought on by wealth, fame and the other trappings of celebrity. It was coined by Robert B. Millman, professor of psychiatry at the Weill Cornell Medical College of Cornell University.
ASN differs from conventional narcissism in that it develops after childhood and is triggered and supported by the celebrity-obsessed society: fans, assistants and tabloid media all play into the idea that the person really is vastly more important than other people, triggering a narcissistic problem that might have been only a tendency, or latent, and helping it to become a full-blown personality disorder. "Millman says that what happens to celebrities is that they get so used to people looking at them that they stop looking back at other people."
In its presentation and symptoms, it is indistinguishable from narcissistic personality disorder, differing only in its late onset and its support by large numbers of others. "The lack of social norms, controls, and of people telling them how life really is, also makes these people believe they're invulnerable," so that the person with ASN may suffer from unstable relationships, substance abuse and erratic behaviour.
A famous fictional character with ASN is Norma Desmond, the main character of Sunset Boulevard.
References
Narcissism | Acquired situational narcissism | Biology | 291 |
45,116,490 | https://en.wikipedia.org/wiki/User%20activity%20monitoring | In the field of information security, user activity monitoring (UAM) or user activity analysis (UAA) is the monitoring and recording of user actions. UAM captures user actions, including the use of applications, windows opened, system commands executed, checkboxes clicked, text entered/edited, URLs visited and nearly every other on-screen event to protect data by ensuring that employees and contractors are staying within their assigned tasks, and posing no risk to the organization.
User activity monitoring software can deliver video-like playback of user activity and process the videos into user activity logs that keep step-by-step records of user actions that can be searched and analyzed to investigate any out-of-scope activities.
Background
The need for UAM rose due to the increase in security incidents that directly or indirectly involve user credentials, exposing company information or sensitive files. In 2014, there were 761 data breaches in the United States, resulting in over 83 million exposed customer and employee records. With 76% of these breaches resulting from weak or exploited user credentials, UAM has become a significant component of IT infrastructure. The main populations of users that UAM aims to mitigate risks with are:
Contractors
Contractors are used in organizations to complete information technology operational tasks. Remote vendors that have access to company data are risks. Even with no malicious intent, an external user like a contractor is a major security liability.
Users
70% of regular business users admitted to having access to more data than necessary. Generalized accounts give regular business users access to classified company data. This makes insider threats a reality for any business that uses generalized accounts.
IT users
Administrator accounts are heavily monitored due to the high-profile nature of their access. However, current log tools can generate “log fatigue” on these admin accounts. Log fatigue is the overwhelming sensation of trying to handle a vast amount of logs on an account as a result of too many user actions. Harmful user actions can easily be overlooked with thousands of user actions being compiled every day.
Overall risk
According to the Verizon Data Breach Incident Report, “The first step in protecting your data is in knowing where it is and who has access to it.” In today's IT environment, “there is a lack of oversight and control over how and who among employees has access to confidential, sensitive information.” This apparent gap is one of many factors that have resulted in a major number of security issues for companies.
Components
Most companies that use UAM usually separate the necessary aspects of UAM into three major components.
Visual forensics
Visual forensics involves creating a visual summary of potentially hazardous user activity. Each user action is logged, and recorded. Once a user session is completed, UAM has created both a written record and a visual record, whether it be screen captures or video of exactly what a user has done. This written record differs from that of a SIEM or logging tool, because it captures data at a user-level not at a system level –providing plain English logs rather than SysLogs (originally created for debugging purposes). These textual logs are paired with the corresponding screen-captures or video summaries. Using these corresponding logs and images, the visual forensics component of UAM allows for organizations to search for exact user actions in case of a security incident.
In the case of a security threat, i.e. a data breach, Visual forensics are used to show exactly what a user did, and everything leading up to the incident. Visual Forensics can also be used to provide evidence to any law enforcement that investigate the intrusion.
User activity alerting
User activity alerting serves the purpose of notifying whoever operates the UAM solution to a mishap or misstep concerning company information. Real-time alerting enables the console administrator to be notified the moment an error or intrusion occurs. Alerts are aggregated for each user to provide a user risk profile and threat ranking. Alerting is customizable based on combinations of users, actions, time, location, and access method. Alerts can be triggered simply such as opening an application, or entering a certain keyword or web address. Alerts can also be customized based on user actions within an application, such as deleting or creating a user and executing specific commands.
User behavior analytics
User behavior analytics add an additional layer of protection that will help security professionals keep an eye on the weakest link in the chain. By monitoring user behavior, with the help of dedicated software that analyzes exactly what the user does during their session, security professionals can attach a risk factor to the specific users and/or groups, and immediately be alerted with a red flag warning when a high-risk user does something that can be interpreted as a high-risk action such as exporting confidential customer information, performing large database queries that are out of the scope of their role, accessing resources that they shouldn't be accessing and so forth.
Features
Capturing activity
UAM collects user data by recording activity by every user on applications, web pages and internal systems and databases. UAM spans all access levels and access strategies (RDP, SSH, Telnet, ICA, direct console login, etc.). Some UAM solutions pair with Citrix and VMware environments.
User activity logs
UAM solutions transcribe all documented activities into user activity logs. UAM logs match up with video-playbacks of concurrent actions. Some examples of items logged are names of applications run, titles of pages opened, URLs, text (typed, edited, copied/pasted), commands, and scripts.
Video-like playback
UAM uses screen recording technology that captures individual user actions. Each video-like playback is saved and accompanied by a user activity log. Playbacks differ from traditional video playback to screen scraping, which is the compiling of sequential screen shots into a video-like replay. The user activity logs combined with the video-like playback provides a searchable summary of all user actions. This enables companies to not only read, but also view exactly what a particular user did on company systems.
Privacy
Whether user activity monitoring would jeopardize one's privacy depends on how privacy is defined under different theories. While in "control theory", privacy is defined as the levels of control that an individual has over his or her personal information, the "unrestricted access theory" defines privacy as the accessibility of one's personal data to others. Using the control theory, some argues that the monitoring system decreased people's control over information, and therefore, regardless of what whether the system is actually put into use, will lead to a loss of privacy.
Audit and compliance
Many regulations require a certain level of UAM while others only require logs of activity for audit purposes. UAM meets a variety of regulatory compliance requirements (HIPAA, ISO 27001, SOX, PCI, and others). UAM is typically implemented for the purpose of audits and compliance, to serve as a way for companies to make their audits easier and more efficient. An audit information request for information on user activity can be met with UAM. Unlike normal log or SIEM tools, UAM can help speed up an audit process by building the controls necessary to navigate an increasingly complex regulatory environment. The ability to replay user actions provides support for determining the impact on regulated information during security incident response.
Appliance vs. software
UAM has two deployment models. Appliance-based monitoring approaches that use dedicated hardware to conduct monitoring by looking at network traffic. Software-based monitoring approaches that use software agents installed on the nodes accessed by users.
More commonly, software requires the installation of an agent on systems (servers, desktops, VDI servers, terminal servers) across which users you want to monitor. These agents capture user activity and reports information back to a central console for storage and analysis. These solutions may be quickly deployed in a phased manner by targeting high-risk users and systems with sensitive information first, allowing the organization to get up and running quickly and expand to new user populations as the business requires.
See also
References
Data security
Crime prevention
National security
Online analytical processing
Regulatory compliance
Secure communication
Social information processing | User activity monitoring | Engineering | 1,661 |
377,975 | https://en.wikipedia.org/wiki/Lead%28II%29%20sulfate | Lead(II) sulfate (PbSO4) is a white solid, which appears white in microcrystalline form. It is also known as fast white, milk white, sulfuric acid lead salt or anglesite.
It is often seen in the plates/electrodes of car batteries, as it is formed when the battery is discharged (when the battery is recharged, then the lead sulfate is transformed back to metallic lead and sulfuric acid on the negative terminal or lead dioxide and sulfuric acid on the positive terminal). Lead sulfate is poorly soluble in water.
Structure
Anglesite (lead(II) sulfate, ) adopts the same orthorhombic crystal structure as celestite (strontium sulfate, ) and barite (barium sulfate, ). All three minerals' structures are in the space group Pbnm (number 62). Each lead(II) ion is surrounded by 12 oxygen atoms from 7 sulfate ions, forming a PbO12 polyhedron. The lead–oxygen distances range from 2.612 Å to 3.267 Å and the average distance is 2.865 Å.
Manufacturing
Lead(II) sulfate is prepared by treating lead oxide, hydroxide or carbonate with warm sulfuric acid or by treating a soluble lead salt with sulfuric acid.
Alternatively, it can be made by the interaction of solutions of lead nitrate and sodium sulfate.
Toxicology
Lead sulfate is toxic by inhalation, ingestion and skin contact. It is a cumulative poison, and repeated exposure may lead to anemia, kidney damage, eyesight damage or damage to the central nervous system (especially in children). It is also corrosive - contact with the eyes can lead to severe irritation or burns. Typical threshold limit value is 0.15 mg/m3.
Mineral
The naturally occurring mineral anglesite, PbSO4, occurs as an oxidation product of primary lead sulfide ore,
Basic and hydrogen lead sulfates
A number of lead basic sulfates are known: PbSO4·PbO; PbSO4·2PbO; PbSO4·3PbO; PbSO4·4PbO. They are used in manufacturing of active paste for lead–acid batteries. A related mineral is leadhillite, 2PbCO3·PbSO4·Pb(OH)2.
At high concentration of sulfuric acid (>80%), lead hydrogensulfate, Pb(HSO4)2, forms.
Chemical properties
Lead(II) sulfate can be dissolved in concentrated HNO3, HCl, H2SO4 producing acidic salts or complex compounds, and in concentrated alkali giving soluble tetrahydroxidoplumbate(II) [Pb(OH)4]2− complexes.
Lead(II) sulfate decomposes when heated above 1000 °C:
Applications
Lead-acid storage batteries
Paint pigments
Laboratory reagent
See also
Lead paint
References
External links
Case Studies in Environmental Medicine (CSEM): Lead Toxicity
ToxFAQs: Lead
National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
Sulfates
Lead(II) compounds | Lead(II) sulfate | Chemistry | 640 |
47,919,116 | https://en.wikipedia.org/wiki/Turhan%20Nejat%20Veziro%C4%9Flu | Turhan Nejat Veziroğlu (24 January 1924 – 5 September 2024), sometimes referred to as TN Veziroglu, was a professor emeritus at the University of Miami, and during the 1970s chaired its mechanical engineering department and was its associate dean for research. He was the President of the International Association for Hydrogen Energy and founding editor of the International Journal of Hydrogen Energy. A research center at the University of Niğde, Turkey carries his name.
Early life and education
Veziroğlu was born and raised in Turkey, where he attended elementary and middle school in Izmir, then attended Pertevniyal High School in Istanbul. After attending Istanbul Technical University for one and a half years, he became a student in England during World War II, receiving a B.Sc. from University of London in 1946, along with an A.C.G.I. in mechanical engineering in London that same year. In 1947, he received the D.I.C. in engineering and technology from the Imperial College of Science and Technology in London. In 1951, Veziroğlu wrote his Ph.D. dissertation at the University of London.
Veziroğlu returned to Turkey after graduating, joining the Turkish military for compulsory military service, in the ordnance section, inventions examiner, from 1952 to 1953. He worked as an engineer and scientific advisor for the Office of Soil Products in Ankara from 1954 to 1956, including as Deputy Director of Steel Silos. He spent a summer working on nuclear engineering at the Electric Power Research Institute in Ankara during 1956. He was an engineering consultant in Istanbul during 1957 and 1958, then worked in his family's business, Veziroğlu Construction Company, as technical director from 1959 to 1961.
Work
In 1962, Veziroğlu became an associate professor at the University of Miami in Coral Gables, Florida, becoming full professor of mechanical engineering there in 1966, retaining that title through 2009, when he became professor emeritus. He was made a full member of their research faculty in 1969, serving as Director of Graduate Studies from 1965 to 1971, and as chairman of the department of Mechanical Engineering from 1971 through 1975.
Veziroğlu created the first engineering Ph.D program at the university, and in 1974 was organizer of an early conference on hydrogen energy.
He then accepted a visiting professorship to the Middle East Technical University. In 1973, shortly after the energy crisis, Veziroğlu established the Clean Energy Research Institute within the university, and was its director from 1974 onward. He organized a conference on hydrogen energy in 1974. He became Associate Dean for Research in 1975, and maintained that role through 1979. He was a visiting lecturer at Xi'an Jiatong University during the summer of 1980, and a visiting lecturer at the Atomic Research Laboratories in Argentina during the summer of 1985.
As a researcher in hydrogen energy and two-phase flows, Veziroğlu has co-authored over 300 scientific papers, and was a founding editor of the International Journal of Hydrogen Energy. Veziroğlu was also named honorary editor-in-chief of Engineering Science and Technology, The International Journal of Sciences and Engineering: Research and Applications, and International Scientific Journal for Alternative Energy and Ecology.
In his seventies, Veziroğlu took a leave of absence from the University of Miami, becoming founding director of International Centre for Hydrogen Energy Technologies. He returned to his professorship in 2007, and on May 15, 2009 became professor emeritus. In 2010, the 10th International Conference on Clean Energy was dedicated to his work.
He was founding editor of the International Journal of Hydrogen Energy and founder of Hydrogen Energy Publications LLC. He was president of the International Association for Hydrogen Energy, initiator of the World Hydrogen Energy Conference, and initiator of the World Hydrogen Technology Convention.
Honors
Chair, commission on energy, World Constitution and Parliament Association (WCPA)
Turkish Presidential Science Award, 1975
Medal of the City of Paris, Paris, France, 1977
Kurchatov Medal from the Kurchatov Institute of Atomic Energy, Moscow, USSR, 1982.
1995 science award, Academy of Television Arts & Sciences, January 1995
Honorary degrees
Honorary doctorate from Anadolu University in Eskişehir, Turkey, October 1998.
Honorary doctorate from the Donetsk State Technical University in the Ukraine, March 2001.
Honorary professorship, Ministry of Education, People's Republic of China, 1981.
Personal life
Married since 2006 to Ayfer Kale; the couple has one daughter, Lili Ferruh. Veziroğlu was Vice President and Advisor of Hydrogen Development for Fuel Cells at Apollo Energy Systems. Veziroğlu has been a board member of the Learning Disabilities Foundation since 1970. In 2013, Veziroğlu and his family donated money to the University of Miami to establish a named professorship.
Selected publications
1996, "Performance analysis of photovoltaic thermal air heaters," Yigit, Liu, Kakac, Veziroglu & etc., Elsevier.
2001, "From hydrogen economy to hydrogen civilization," VA Goltsov, TN Veziroglu, International Journal of Hydrogen Energy.
2002, "Current status of hydrogen energy," M Momirlan, TN Veziroglu, Renewable and Sustainable Energy Reviews, Elsevier.
2004, "A review of hydrogen storage systems based on boron and its compounds," E Fakioğlu, Y Yürüm, TN Veziroğlu, Elsevier.
2005, "Wind energy and the hydrogen economy — review of the technology,"' SA Sherif, F Barbir, TN Veziroglu, Solar Energy, Vol. 78, No. 5, pp. 647–660.
2008, "Advances in biological hydrogen production processes," D Das, TN Veziroglu, International Journal of Hydrogen Energy.
References
Notes
Year of birth missing (living people)
2024 deaths
20th-century Turkish engineers
Academic staff of Middle East Technical University
Turkish emigrants to the United States
Alumni of the University of London
University of Miami faculty
Mechanical engineers
Recipients of TÜBİTAK Science Award
Alumni of Imperial College London
20th-century American engineers
Turkish men centenarians | Turhan Nejat Veziroğlu | Engineering | 1,269 |
1,156,934 | https://en.wikipedia.org/wiki/Ammonium%20carbonate | Ammonium carbonate is a chemical compound with the chemical formula . It is an ammonium salt of carbonic acid. It is composed of ammonium cations and carbonate anions . Since ammonium carbonate readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a leavening agent and also as smelling salt. It is also known as baker's ammonia and is a predecessor to the more modern leavening agents baking soda and baking powder. It is a component of what was formerly known as sal volatile and salt of hartshorn, and produces a pungent smell when baked. It comes in the form of a white powder or block, with a molar mass of 96.09 g/mol and a density of 1.50 g/cm3. It is a strong electrolyte.
Production
Ammonium carbonate is produced by combining carbon dioxide and aqueous ammonia. About 80,000 tons/year were produced as of 1997.
An orthorhombic ammonium carbonate monohydrate is known (). It crystallizes in an ammonia solution exposed in a carbon dioxide-rich atmosphere.
Decomposition
Ammonium carbonate slowly decomposes at standard temperature and pressure through two pathways. Thus any initially pure sample of ammonium carbonate will soon become a mixture including various byproducts.
Ammonium carbonate can spontaneously decompose into ammonium bicarbonate and ammonia:
Which further decomposes to carbon dioxide, water and another molecule of ammonia:
Uses
Leavening agent
Ammonium carbonate may be used as a leavening agent in traditional recipes, particularly those from northern Europe and Scandinavia (e.g. Amerikaner, Speculoos, Tunnbröd or Lebkuchen). It was the precursor to today's more commonly used baking powder.
Originally made from ground deer horn and called hartshorn, today it is called baker's ammonia. It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard, white or translucent mass. It acts as a heat activated leavening agent and breaks down into carbon dioxide (leavening), ammonia (which needs to dissipate) and water. It is sometimes combined with sodium bicarbonate double acting baking powder and to help mask any ammonia smell not baked out.
It also serves as an acidity regulator and has the E number E503. It can be replaced with baking powder, but this may affect both the taste and texture of the finished product. Baker's ammonia should be used to create thin dry baked goods like crackers and cookies. This allows the strong ammonia smell to bake out. It should not be used to make moist baked items like cake since ammonia is hydrophilic and will leave a strong bitter taste.
Its use as a leavening agent, with associated controversy, goes back centuries:
Other uses
Ammonium carbonate is the main component of smelling salts, although the commercial scale of their production is small. Buckley's cough syrup from Canada today uses ammonium carbonate as an active ingredient intended to help relieve symptoms of bronchitis. It is also used as an emetic. It is also found in smokeless tobacco products, such as Skoal, and it is used in aqueous solution as a photographic lens cleaning agent, such as Eastman Kodak's "Kodak Lens Cleaner."
It is also used for luring of apple maggots in Washington State, to monitor the spread of the infestation and adjust the borders of the Apple Maggot Quarantine Area.
See also
Ammonium bicarbonate
Ammonium nitrate
Sal ammoniac, the mineralogical form of ammonium chloride
References
Carbonates
Ammonium compounds
Leavening agents | Ammonium carbonate | Chemistry | 763 |
11,180,183 | https://en.wikipedia.org/wiki/OMNIS | OMNIS (Office des Mines Nationales et des Industries Stratégiques, formerly known as Office Militaire National pour les Industries Stratégiques) is the Malagasy government organisation, operating under the auspices of the Ministry of Energy, responsible for:
Hydrocarbons:
– Putting in place and updating the legal framework for upstream oil and gas activities in Madagascar
– Acquisition of technical exploration data (geological, geophysical and drilling)
– Promotion of potentially hydrocarbon-bearing areas
– Management of existing and newly acquired exploration data
– Laboratory analysis of samples (rock, oil and gas)
Mining:
– Promotion of the Malagasy mining sector
– Development of basic sectoral infrastructure relevant to various minerals
– Undertaking of minerals research including energy minerals (radioactive minerals, fossil fuels, etc.)
– Development of and feasibility studies for mining projects, minerals production, etc.
– Assistance and support to national and international mining sector companies
– Promotion of partnership contracts
The acting Director General of OMNIS is Mr. Joeli Valerien Lalaharisaina, who was formerly its Deputy Director General.
References
https://web.archive.org/web/20070614182924/http://www.energy.gov.mg/
Google Earth Map of Petroleum Licenses in Madagascar
Energy in Madagascar
Energy organizations | OMNIS | Engineering | 262 |
2,863,567 | https://en.wikipedia.org/wiki/The%20Iron%20Bridge | The Iron Bridge is a cast iron arch bridge that crosses the River Severn in Shropshire, England. Opened in 1781, it was the first major bridge in the world to be made of cast iron. Its success inspired the widespread use of cast iron as a structural material, and today the bridge is celebrated as a symbol of the Industrial Revolution.
The geography of the deep Ironbridge Gorge, formed by glacial action during the last ice age, meant that there are industrially useful deposits of coal, iron ore, limestone and fire clay present near the surface where they are readily mined, but also that it was difficult to build a bridge across the river at this location. To cope with the instability of the banks and the need to maintain a navigable channel in the river, a single span iron bridge was proposed by Thomas Farnolls Pritchard. After initial uncertainty about the use of iron, construction took place over 2 years, with Abraham Darby III responsible for the ironwork. The bridge crosses the Ironbridge Gorge with a main span of , allowing sufficient clearance for boats to pass underneath.
In 1934 it was designated a scheduled monument and closed to vehicular traffic. Tolls for pedestrians were collected until 1950, when the bridge was transferred into public ownership. After being in a poor state of repair for much of its life, extensive restoration works in the latter half of the 20th century have protected the bridge. The bridge, the adjacent settlement of Ironbridge and the Ironbridge Gorge form the UNESCO Ironbridge Gorge World Heritage Site.
History
Background
The Ironbridge Gorge was formed at the end of the last ice age by the overflowing of Lake Lapworth, which resulted in the exposure of useful deposits of resources such as coal, iron ore, fire clay and limestone near the surface where they were readily mined. With the river providing a means of transport, the local area was an important centre of the emerging Industrial Revolution.
Abraham Darby I first smelted local iron ore with coke made from Coalbrookdale coal in 1709, and in the coming decades Shropshire became a centre for industry due to the low price of fuel from local mines. The River Severn was used as a key trading route, but it was also a barrier to travel around the deep Ironbridge Gorge, especially between the then important industrial parishes of Broseley and Madeley, the nearest bridge being at Buildwas away. The Iron Bridge was therefore proposed to link the industrial town of Broseley with the smaller mining town of Madeley and the industrial centre of Coalbrookdale. The use of the river by boat traffic and the steep sides of the gorge meant that any bridge should ideally be of a single span, and sufficiently high to allow tall ships to pass underneath. The steepness and instability of the banks was problematic for building a bridge, and there was no point where roads on opposite sides of the river converged.
The Iron Bridge was the first of its kind to be constructed, although not the first to be considered nor the first iron bridge of any kind. An iron bridge was partly constructed at Lyons in 1755, but was abandoned for reasons of cost, and a span wrought iron footbridge over an ornamental waterway was erected in Kirklees, Yorkshire, in 1769.
Proposal
In 1773, architect Thomas Farnolls Pritchard wrote to his 'iron mad' friend and local ironmaster, John Wilkinson of Broseley, to suggest building a bridge out of cast iron. Although he specialised in the design of chimneypieces and other items of interior decoration, and in funerary monuments, he had also previously designed both wooden and stone bridges.
During the winter of 1773–74, local newspapers advertised a proposal to petition Parliament for leave to construct an iron bridge with a single span. In 1775, a subscription raised funds of between £3000 and £4000 (equivalent to £ to £ in 2016), and Abraham Darby III, the grandson of Abraham Darby I and an ironmaster working at Coalbrookdale, was appointed treasurer to the project.
In March 1776, the Act to build a bridge received Royal assent. It had been drafted by Thomas Addenbrooke, secretary of the trustees, and John Harries, a London barrister, then presented to the House of Commons by Charles Baldwyn, MP for Shropshire. Abraham Darby III was commissioned to cast and build the bridge. In May 1776, the trustees withdrew Darby's commission, and instead advertised for plans for a single arch bridge to be built in "stone, brick or timber". No satisfactory proposal was made, and the trustees agreed to proceed with Pritchard's design, but there was continued uncertainty about the use of iron, and conditions were set on the cost and duration of the construction. In July 1777 the span of the bridge was decreased to , and then increased again to , possibly in order to accommodate a towpath.
Construction
The site, adjacent to where a ferry had run between Madeley and Benthall, was chosen for its high approaches on each side and the relative solidity of the ground. The Act of Parliament described how the bridge was to be built from a point in Benthall parish near the house of Samuel Barnett to a point on the opposite shore near the house of Thomas Crumpton. Pritchard died on 21 December 1777 in his towerhouse at Eyton on Severn, only a month after work had begun, having been ill for over a year.
The bridge is built from five sectional cast-iron ribs that give a span of . The construction of the bridge used of iron, and there are almost 1,700 individual components, the heaviest weighing . Components were cast individually to fit with each other, rather than being of standard sizes, with discrepancies of up to several centimetres between 'identical' components in different locations.
The masonry and abutments were constructed between 1777 and 1778, and the ribs were lifted into place in the summer of 1779. The bridge first spanned the river on 2 July 1779, and it was opened to traffic on 1 January 1781.
In 1997, a watercolour by Elias Martin was discovered in a Stockholm museum, which showed the bridge under construction in 1779. The painting shows a moveable wooden scaffold consisting of derrick poles standing in the river bed being used as a crane to position the half-ribs of the bridge, which had been taken to the site by boat from Darby's foundry downstream. Using the approach depicted in the painting, a half-size replica of the main section of the bridge was built in 2001 as part of the research for the BBC's Timewatch programme, which was shown the following year.
Design
The bridge is to a carpenters' design typically used for wood structures, built from five sectional cast-iron ribs that give a span of . The interlocking rings between the arches make this a truss arch. Exactly of iron was used in the construction of the bridge, and there are almost 1,700 individual components, the heaviest weighing . Components were cast individually to fit with each other, rather than being of standard sizes, with discrepancies of up to several centimetres between 'identical' components in different locations.
Decorative rings and ogees between the structural ribs of the bridge suggest that the final design was Pritchard's, as the same elements appear in a gazebo he rebuilt. A foreman at the foundry, Thomas Gregory, drew the detailed designs for the members, resulting in the use of carpentry jointing details such as mortise and tenon joints and dovetails.
The two outer ribs are engraved with the words: "This bridge was cast at Coalbrook-Dale and erected in the year MDCCLXXIX" (Roman numerals for 1779).
Two supplemental arches, of similar cast iron construction, carry a towpath on the southern bank and also act as flood arches. A stone arch with a brick vault carries a small path on the northern (town side) bank.
Material
The Iron Bridge is made of cast iron. This is immensely strong in compression, but performs less well than steel and wrought iron when subjected to tension or bending moments, because of its brittleness and lower tensile strength. Analysis of an arch and a strut from the Iron Bridge revealed the following elemental compositions:
The presence of 0.1% sulphur in cast iron is at the upper limit of what is acceptable, but the presence of sufficient manganese leads to the formation of harmless manganese sulphide.
Puddled wrought iron was a much better structural material than cast iron but not widely available until after 1800, eventually becoming the preferred material for bridges, rails, ships and buildings until new steel making processes such as the Bessemer process were developed in the late 19th century.
Cost
Darby had agreed to construct the bridge with a budget of £3,250 (equivalent to £426,353 in 2023) and this was raised by subscribers to the project, mostly from Broseley. While the actual cost of the bridge is unknown, contemporary records suggest it was as high as £6,000 (£787,113 in 2023), and Darby, who was already indebted from other ventures, agreed to cover the excess. However, by the mid-1790s the bridge was highly profitable, and tolls were giving the shareholders an annual dividend of 8 per cent.
Later history
The opening of the bridge resulted in changes in the pattern of settlement in the gorge, and roads around the bridge were improved in the years after its construction. The town of Ironbridge, taking its name from the bridge, developed at the northern end. The trustees, as well as local hotel keepers and coach operators, promoted interest in the bridge among members of high society.
Repairs
In July 1783, a wall was built in order to prevent the north bank from slipping into the river. Cracks were found in the stone land arch on the south side in December 1784, and the neighbouring abutment showed signs of movement. The Gorge is very prone to landslides, and over 20 are recorded in the British Geological Survey's National Landslide Database in the area. It was suspected that the sides of the gorge were moving towards the river, forcing the feet of the arch towards each other, and consequently repairs were carried out in 1784, 1791 and 1792.
It was the only bridge on the River Severn to survive the flood of February 1795 undamaged, due to its strength and small profile against the floodwaters. The medieval bridge at Buildwas was replaced with a cast iron bridge by Thomas Telford, which, by virtue of superior design, required half the quantity of iron despite a longer span of . The Buildwas Bridge survived until 1906. Contrary to a common misconception, Telford was not responsible for the construction of the bridge itself.
In 1800 the trustees commissioned repairs which lasted for several years, which involved the replacement of the stone land arches with wooden ones to relieve pressure on the main span. A proposal to build a rigid support between the abutments to keep them apart was found to be impossible with the available technology, but was achieved during the later restoration of the bridge in the 1970s. In 1812, its construction was described as "very bad" by Charles Hutton, and he predicted that it would not last for long, "though not from any deficiency in the iron-work", but due to cracks that had appeared in the stonework. The timber arches were replaced with cast iron ones in December 1820, and further repairs were necessary throughout the remainder of the 19th century.
Around 1870, "Sir B. Baker stated that it had required patching for ninety years, because the arch and the high side arches would not work together. Expansion and contraction broke the high arch and the connexions between the arches. When it broke they fished it. Then the bolts sheared or the ironwork broke in a new place. He advised that there was nothing unsafe; it was perfectly strong and the stress in vital parts moderate. All that needed to be done was to fish the fractured ribs of the high arches, put oval holes in the fishes, and not screw up the bolts too tight."
On 24 August 1902, a length of parapet collapsed into the river, and a section of deck plate weighing around fell from the bridge in July 1903. The opening of a toll-free concrete bridge in 1909 caused concern among the trustees, but it continued to be used by vehicles and pedestrians.
Closure to vehicles
A 1923 report by engineering consultants Mott, Hay and Anderson suggested that other than the paintwork, the main span of the bridge was in good condition. It was suggested that the metal deck of the bridge was dangerously heavy, and that after removing the dead weight the bridge should be reopened to vehicles no heavier than 2 tons and restricted to the centre of the roadway. A weight limit of 4 tons was imposed, but the housing boom of the 1930s meant that drivers distributing tiles produced at Jackfield were insistent that they should be allowed to use the bridge, so the trustees took the decision to close it to vehicular traffic with effect from 18 June 1934. Tolls for pedestrians were collected until 1950, when ownership of the bridge was transferred to Shropshire County Council. The tolls collected only marginally covered the cost of collection, leaving no budget for conservation, and the bridge had not been cleaned or painted for many years. Due to its poor condition, between the 1940s and 1970s a number of suggestions were made to scrap and replace the bridge, or move it to a different location. In 1956 the County Council made a proposal to demolish the bridge and replace it with a new one, but this plan did not come to fruition. The Ironbridge Gorge Museum Trust was set up in 1967 with the aim of protecting industrial heritage in the Ironbridge Gorge, and was able to secure funding from the council to carry out repairs.
Restoration
With funding from Shropshire County Council, the Historic Buildings Council for England, and the nascent Ironbridge Gorge Museum Trust, a programme of repairs took place on the foundations of the bridge at a cost of £147,000 between 1972 and 1975. The consulting engineers Sandford, Fawcett, Wilton and Bell decided to place a ferro-concrete inverted arch under the river to counter inward movement of the bridge abutments. The arch was built by the Tarmac Construction Company, starting in the spring of 1973, but unusually high summer floods washed over the cofferdam, frustrating hopes that the work could be done in a single summer. Filling material was removed from the south abutment to reduce its weight, and the arch through it was reinforced with concrete. The road surface was replaced with a lighter tarmac, the stone of the abutments was renewed and the toll-house was restored as an information centre. In 1980, the structure was painted for the first time in the 20th century, and the work was complete for the bicentenary of the opening, which was celebrated on 1 January 1981.
Between 1999 and 2000, the bridge was scaffolded to allow examination by English Heritage. The bridge was also repainted and minor repairs were carried out. In January 2017 English Heritage announced a £1.2 million restoration project on the Iron Bridge, starting in September 2017, the "biggest ever conservation project" undertaken by English Heritage. The cost was quoted in 2018 at £3.6 million, with English Heritage describing it as "an ambitious conservation of its ribs and arches, its stonework and decking." The project was created after extensive surveys of the area revealed that the historic structure was under threat due to stresses in the ironwork dating from the original construction, ground movement over the centuries, and an earthquake in the 19th century. Apart from the structural restoration, the bridge was also reverted from blue-grey to its original red-brown colour after forensic analysis revealed this was how the bridge looked when it was first erected.
The project was partly funded through the use of crowdfunding in which £47,545 was raised. It also received a €1,000,000 donation from the Hermann Reemtsma Foundation, a German foundation which mainly promotes cultural and social projects in northern Germany. This would also be the foundation's first funding in the United Kingdom. Following the works the bridge was reopened on 6 December 2018.
Recognition
The bridge, the adjacent settlement of Ironbridge and the Ironbridge Gorge form the UNESCO Ironbridge Gorge World Heritage Site, which was created in 1986. The bridge is a Grade I listed building, and is owned by Telford and Wrekin Council.
In 1934 it was designated a Scheduled Ancient Monument, and in 1979, the bridge was recognised by the American Society of Civil Engineers as an International Civil Engineering Landmark.
In 2020 the conservation and restoration work on the bridge was honoured in the European Heritage Awards/Europa Nostra Awards, which includes up to 30 of the most outstanding heritage projects from all parts of Europe within the EU and EEA.
Influence on bridge design
The bridge, as the first bridge of significant size built of metal, had "considerable influence on developments in the fields of technology and architecture".
The successful use of cast iron in 1781 pioneered the choice of that material for many subsequent bridges, and cast iron arches of considerable span were constructed late in the 18th and early in the 19th century.
In 1786, the revolutionary author and polymath Thomas Paine had models built to demonstrate the use of cast iron for bridges, and promoted these to the Academy of Sciences at Paris, and to the Royal Society in England. He went on to have manufactured and erected "a complete rib of 90 feet span, and 5 feet of height from the chord line to the center of the arch", weighing three tons. This was followed by a complete bridge of five ribs and span which he had erected in a field in Paddington, but without buttresses it was merely for display and was dismantled after a year.
In 1793–96, the Wearmouth Bridge was built with a span of , constructed from cast iron in the form of cast voussoirs, somewhat like the voussoirs of a masonry bridge. The bridge used some of the iron from Paine's bridge, which had been returned to the foundry in Rotherham.
In 1795, a large flood in the Severn swept away all the bridges in the vicinity, except the Iron Bridge, where the open structure allowed the floodwaters to pass through. Thomas Telford was Surveyor of Public Works in Shropshire at the time. His design for the replacement bridge at Buildwas incorporated a high arch like the Iron Bridge, but it had a span wider and used less than half the amount of iron. Telford went on to design a series of cast iron bridges, the oldest of which to survive is the Craigellachie Bridge.
In 1799, the Coalport Bridge was rebuilt after the flood as a single span with three cast iron ribs. This 1799 version was re-modelled in 1818 with two additional ribs, and survives to the present day.
Artistic depictions
Over fifty painters and engravers came to the area around Coalbrookdale between 1750 and 1830 to witness and record the rise of industry and changing landscape. One of the first artists to depict the bridge was William Williams, who was paid 10 guineas () in October 1780 by Darby for a drawing of the bridge. An engraving by Michael Angelo Rooker proved popular, and a copy was purchased by Thomas Jefferson where it was displayed in the dining room of Monticello.
In 1979, the Royal Academy of Arts held an exhibition entitled "A View from the Iron Bridge" to commemorate the bicentenary of the bridge.
See also
List of crossings of the River Severn
Listed buildings in The Gorge
Notes
References
Citations
Sources
External links
Iron Bridge & Tollhouse – Ironbridge Gorge Museums Trust
The Iron Bridge on the English Heritage website
Virtual tour, from the BBC (VRML plugin required, then use PgUp/PgDn to move between viewpoints)
A geological assessment of the landslides in the Ironbridge Gorge, Shropshire (Report)
Archaeological sites in Shropshire
Bridges across the River Severn
Bridges in Shropshire
Cast-iron arch bridges in England
English Heritage sites in Shropshire
Grade I listed buildings in Shropshire
Historic Civil Engineering Landmarks
Industrial Revolution in England
Telford and Wrekin
Scheduled monuments in Shropshire
Bridges completed in 1779
Museums in Shropshire
Ironbridge Gorge
Technology museums in the United Kingdom
Ironbridge Gorge Museum Trust
Former toll bridges in England
Grade I listed bridges
1779 establishments in England
Ironbridge
Coalbrookdale | The Iron Bridge | Engineering | 4,128 |
24,812,935 | https://en.wikipedia.org/wiki/Technomimetics | Technomimetics are molecular systems that can mimic man-made devices. The term was first introduced in 1997. The current set of technomimetic molecules includes motors, rotors, gears, gyroscopes, tweezers, and other molecular devices. Technomimetics can be considered as the essential components of molecular machines and have the primary use in molecular nanotechnology.
See also
Molecular tweezers
References
Nanotechnology
Molecular machines | Technomimetics | Physics,Chemistry,Materials_science,Technology,Engineering | 94 |
52,570,425 | https://en.wikipedia.org/wiki/Zeitschrift%20f%C3%BCr%20Kristallographie%20%E2%80%93%20Crystalline%20Materials | Zeitschrift für Kristallographie – Crystalline Materials is a monthly peer-reviewed scientific journal published in English. The journal publishes theoretical and experimental studies in crystallography of both organic and inorganic substances. The editor-in-chief of the journal is from the University of Münster. The journal was founded in 1877 under the title Zeitschrift für Krystallographie und Mineralogie by crystallographer and mineralogist Paul Heinrich von Groth, who served as the editor for 44 years. It has used several titles over its history, with the present title having been adopted in 2010. The journal is indexed in a variety of databases and has a 2020 impact factor of 1.616.
History
The journal was established in 1877 by Paul von Groth as a German-language publication under the title Zeitschrift für Krystallographie und Mineralogie, and he served as its editor until the end of 1920. Groth was appointed as the inaugural Professor of Mineralogy at the University of Strasbourg in 1872 and made great contributions to the disciplines of mineralogy and crystallography both there and, from 1883, as the curator at the Deutsches Museum in Munich. Groth was the first to classify minerals according to their chemical composition and contributed to the understanding of isomorphism and morphotropy in crystalline systems. Using the data from 55 volumes of the journal covering 39 years of publications (1877–1915) plus other sources, Groth produced the five volume work Chemische Krystallographie between 1906 and 1919. This work catalogued the chemical and physical properties of the between 9,000 and 10,000 crystalline substances known at the time.
It has used a series of names over its history (see table below), finally becoming Zeitschrift für Kristallographie – Crystalline Materials in 2010, a name distinguishing it from the 1987 spin-off journal Zeitschrift für Kristallographie – New Crystal Structures.
Special issues
Beginning in December 2002, the journal has produced special issues with articles grouped around a single theme. Topics covered include the analysis of complex materials using pair distribution function methods, borates (double issue), hydrogen storage, in situ crystallisation, mathematical crystallography, mineral structures, nanocrystallography, phononic crystals, photocrystallography, the application of precession electron diffraction methods, twinned crystals, and zeolites (double issue). On four occasions, one or two issues of the journal have been dedicated to the memory of a crystallographer or mineralogist, usually with a theme associated with the individual's work and a description of their contribution to the field. These are summarised in the table below:
Abstracting and indexing
The journal is abstracted and indexed in:
Chemical Abstracts Service
Current Contents/Physical, Chemical and Earth Sciences
EBSCO databases
Inspec
Science Citation Index Expanded
Scopus
According to the Journal Citation Reports, the journal has a 2015 impact factor of 2.560, and it is ranked 8th amongst the 26 crystallography journals.
References
External links
Chemistry journals
Crystallography journals
Monthly journals
Publications established in 1877
Multilingual journals
De Gruyter academic journals
1877 establishments in Germany | Zeitschrift für Kristallographie – Crystalline Materials | Chemistry,Materials_science | 666 |
24,377,704 | https://en.wikipedia.org/wiki/HD%20204313%20b | HD 204313 b is an extrasolar planet which orbits the G-type main sequence star HD 204313, located approximately 155 light years away in the constellation Capricorn. This planet orbits the star at a distance of 3.082 astronomical units and takes 1931 days or 5.29 years to revolve around the star. It has a minimum mass four times that of Jupiter. However the radius is not known since this planet was not detected by the transit method or direct imaging. Instead, this planet was detected by the radial velocity method using the CORALIE Echelle spectrograph mounted on the 1.2 meter Euler Swiss Telescope located at La Silla Observatory in Atacama Desert, Chile on August 11, 2009.
The planet's existence was independently confirmed in 2015, and in 2022 its inclination and true mass were measured via astrometry.
References
Exoplanets discovered in 2009
Giant planets
Capricornus
Exoplanets detected by radial velocity
Exoplanets detected by astrometry | HD 204313 b | Astronomy | 209 |
21,471,974 | https://en.wikipedia.org/wiki/Barth%C3%A9l%C3%A9my%20Bisengimana | Barthélémy Bisengimana Rwema (born 12 May 1935) was a Zairean official who served as head of the Bureau of the President under Mobutu Sese Seko from May 1969 to February 1977. Bisengimana was a member of the Tutsi ethnic group whose rise to prominence was largely the result of the complete dependence of the Banyarwanda upon the central government for power, which made them reliable supporters. A native of Cyangugu Province in Rwanda, in 1961 Bisengimana was the first graduate with a degree in electrical engineering from Lovanium University in Kinshasa.
Bisengima's aided many Congolese Tutsis in North and South Kivu to acquire land and start lucrative businesses. Andre Kalinda, a chief of the Hunde and territorial administrator of Masisi, became the most powerful chief due to his connections with both Bisengimana and the Acogenoki. At his height in 1972, Bisengimana managed to get the Political Bureau of the ruling Mouvement Populaire de la Révolution (MPR) to pass a citizenship decree in which everyone originating from "Ruanda-Urundi" and residing in then-Belgian Congo on or before January 1950 was automatically granted citizenship. This Law 72-002 amended the MPR's statutes and became referred to as "Article 15". When the law, which further allowed the new citizens to claim land rights, went into effect in 1973, a number of Tutsi refugees legally received plantations and ranches that had been previously owned by Belgian settlers. Among these was Bisengimana, who claimed the Osso concession, which contained the largest number of cattle owned by white settlers in Masisi.
Bisengimana was dismissed in 1977, followed allegations of getting kickbacks from a textile plant in Kisangani. Following his removal, there was increasing pressure to reverse Article 15, resulting in the passing of Law 81-002 on 29 June 1981.
Footnotes
References
1935 births
Living people
People from Western Province, Rwanda
Tutsi people
Rwandan exiles
Rwandan refugees
Electrical engineers
Popular Movement of the Revolution politicians
Lovanium University alumni
Democratic Republic of the Congo people of Rwandan descent
Rwandan emigrants to the Democratic Republic of the Congo
21st-century Democratic Republic of the Congo people | Barthélémy Bisengimana | Engineering | 477 |
21,802,302 | https://en.wikipedia.org/wiki/Dexlansoprazole | Dexlansoprazole, is a medication which reduces stomach acid. It is used to treat gastroesophageal reflux disease. Effectiveness is similar to other proton pump inhibitors (PPIs). It is taken by mouth.
Common side effects include diarrhea, abdominal pain, and nausea. Serious side effects may include osteoporosis, low blood magnesium, Clostridioides difficile infection, anaphylaxis, and pneumonia. Use in pregnancy and breastfeeding is of unclear safety. It works by blocking H+/K+-ATPase in the parietal cells of the stomach.
Dexlansoprazole was approved for medical use in the United States in 2009. In Canada in 2016, it was the most expensive Proton-pump inhibitor (PPI) available. In 2022, it was the 186th most commonly prescribed medication in the United States, with more than 2million prescriptions.
Medical use
Dexlansoprazole is used to heal and maintain healing of erosive esophagitis and to treat heartburn associated with gastroesophageal reflux disease (GERD). It lasts longer than lansoprazole, to which it is chemically related, and needs to be taken less often. There is no good evidence that it works better than other PPIs.
Adverse effects
The most significant adverse reactions (≥2%) reported in clinical trials were diarrhea, abdominal pain, bloating, nausea, upper respiratory tract infection, vomiting, and flatulence.
Mechanism of action
Like lansoprazole, dexlansoprazole permanently binds to the proton pump and blocks it, preventing the formation of gastric acid.
Chemistry
Dexlansoprazole is the (R)-(+)-enantiomer of lansoprazole, which is a racemic mixture of its (R)-(+) and (S)-(−)-enantiomers. The Takeda drug has a dual release pharmaceutical formulation, with two types of granules of dexlansoprazole, each with a coating that dissolves at a different pH level.
Pharmacokinetics
Dexlansoprazole ((R)-(+)-lansoprazole) has the same binding affinity to the proton pump as the (S)-enantiomer, but is associated with a three- to five-fold greater area under the plasma drug concentration time curve (AUC) compared with (S)-lansoprazole. With its dual release pharmaceutical formulation, the first quick release produces a plasma peak concentration about one hour after application, with a second delayed release producing another peak about four hours later.
History
Dexlansoprazole was approved in the United States in 2009, in Canada in 2010, and in Mexico in 2011.
Society and culture
Since Kapidex was approved in 2009, there have been reports of dispensing errors because of confusion with the drugs Casodex (bicalutamide) and Kadian (morphine), which have very different uses from Kapidex and from each other. In 2010, the FDA approved a name change for Kapidex to avoid confusion with the two other medications and Takeda began marketing it under the new name Dexilant.
References
Proton-pump inhibitors
Benzimidazoles
Sulfoxides
Pyridines
Enantiopure drugs
Aromatic ethers
Trifluoromethyl compounds
Drugs developed by Takeda Pharmaceutical Company
Wikipedia medicine articles ready to translate | Dexlansoprazole | Chemistry | 730 |
70,173,577 | https://en.wikipedia.org/wiki/Animal%20Locomotion | Animal Locomotion: An Electro-photographic Investigation of Consecutive Phases of Animal Movements is a series of scientific photographs by Eadweard Muybridge made in 1884 and 1885 at the University of Pennsylvania, to study motion in animals (including humans). Published in July 9, 1887, the chronophotographic series comprised 781 collotype plates, each containing up to 36 pictures of the different phases of a specific motion of one subject (over 20,000 images in total).
Following motion studies in California and his lectures with the zoopraxiscope, Muybridge was commissioned by the University of Pennsylvania to oversee the photographic aspects of a scientific study of animal movement. The body of work is celebrated for its contribution to both the art of photography and to science.
History
In 1878, Muybridge published his first series of chronophotographic pictures as 6 cabinet cards entitled The Horse in Motion, from the recordings made as an assignment from industrialist and horse breeder Leland Stanford. The revolutionary images gained worldwide attention and inspired Muybridge to change his career from "photographic view artist" to scientific photographer and lecturer.
In 1879, Muybridge created the zoöpraxiscope (animal action viewer), a projection device that created cyclical animations of animal movement, incorporating technologies from photography, the magic lantern and the zoetrope. The photographer created painted sequences on the glass zoöpraxiscope discs that were based on his motion-study photographs to produce an early form of animation. Muybridge used these to illustrate his lectures that were presented to audiences in the U.S. and Europe, marking his contribution to photography and film in relation to the "experience of time within modernity."
In a 1885 news report, the photographer stated that his interest in animal movement was inspired by observing an eagle flying in the Yosemite Valley in California some years prior. Muybridge described the bird as making "numerous flaps with its wings, but in flying across a valley to another peak it went for a distance of over a mile with but one flap of the wings. I was convinced that individual feather movements upheld and propelled the bird, and I can prove by the negative plates of the eagle whose flight we photographed last Thursday that my conclusion was correct." These earlier photographs in California formed the basis for his later work with the University of Pennsylvania.
Commission
The Animal Locomotion project was a collaborative endeavor between the photographer and the institutional commissioning committee at the University of Pennsylvania. In 1883, Muybridge met with William Pepper and J.B. Lippincott to discuss a plan for a scientific study focused on the analysis of animal and human movement. The university contributed $5,000, seeing the proposed project as important research that would benefit anthropology, physiology, medicine and sports. The commission was appointed in March 1884 and included the University's professors Pepper, Joseph Leidy, George Frederick Barker, Lewis M. Haupt and emeritus Harrison Allen, as well as Thomas Eakins and Edward Hornor Coates of the Pennsylvania Academy of the Fine Arts. The project would eventually last more than three years, and costs rose to almost $30,000, but the University believed the unexpected amount of time and money to be well spent. The huge body of work was thought to be of everlasting importance to science and art and it would take years to examine all the material critically.
From spring 1884 to autumn 1885, Muybridge and his team produced over 100,000 images, mostly at an outdoor studio on the University grounds' northeast corner of 36th and Pine, recording the motions of animals from the veterinary hospital, and from humans: University professors, students, athletes, Blockley Almshouse patients, and local residents. Thomas Eakins worked with him briefly, although the painter preferred working with multiple exposures on a single negative, whereas Muybridge preferred capturing motion through the use of multiple cameras.
Muybridge spent three weeks of August and September 1884, and another three weeks of August 1885, at the Philadelphia Zoo photographing all kinds of animals. Published plates with exotic species include Capybara Walking depicting the world's largest rodent, Ostrich Running (also printed as a cyanotype) and American Bison Cantering,
The pictures of thoroughbred horses were made at the Gentlemen's Driving Park in Philadelphia.
Technology
At the outdoor studio, Muybridge's team used a array of twenty-four 4 by 5 inch cameras, placed 15 centimeters (6 inches) apart at 15 metres (49 feet) from the track. An improved electro-magnetic shutter system with variable rubber bands regulated the exposures. Muybridge had two additional arrays of smaller, portable cameras made; this allowed more flexible placements and quicker operation. The two arrays of 12 cameras each were usually placed at the front and the back of the track, for views of subjects approaching and receding in addition to the lateral views of the 24-camera set. Many of the published series contain 36 pictures, with moving subjects recorded from two or three angles. Muybridge also made studies of foreshortenings with 6 cameras placed at different angles at the same time (comparable to the later bullet time effect).
The trip-wires caused irregular sequences when subjects didn't maintain a constant gait. Muybridge therefore developed a circuit-breaker for making the successive electrical contacts automatically and at equal intervals, long or short, as desired. Each shutter was connected to a chronographic clock that recorded the exposures. Muybridge carried a telegraphic key with him, which was connected to the clockwork and allowed him to fire the whole series of cameras by a touch.
While working in California, Muybridge had used the wet-plate collodion process in making his albumen-print photographs. Once he arrived in Philadelphia, he began to employ a standardized dry-plate process, involving quicker exposure times; these were printed using the collotype photomechanical process.
Content and publication
The published portfolio contained 19 by 24 inch plates in 36 by 36-inch frames, numbered from 1 to 781 in an order mostly based on types of movement (starting with "Walking" followed by "Walking and turning around", "Starting for a run", "Running", et cetera). The plates came in eleven categorized volumes with title pages: Vol. I. & II. Males (nude)., Vol. III. & IV. Females (nude)., Vol. V. Males (pelvis cloth)., Vol. VI. Females (semi-nude and transparent drapery) and Children., Vol. VII. Males and Females (draped) and Miscellaneous Subjects., Vol. VIII. Abnormal Movements. Men and Women (nude and semi-nude)., Vol. IX. Horses., Vol. X. Domestic Animals., and Vol. XI. Wild Animals and Birds. The classification and order of the subjects suggests a hierarchy from nude human males down to chickens, following the Christian concept of the Great chain of being.
Subscribers had the option of selecting 100 plates of their choosing from the portfolio's prospectus and complete catalog for $100. Complete sets were offered for $600, but sold very poorly; reportedly only 37 proper versions were produced.
Contrary to the animal focus suggested by the title of the collection, there were 514 plates of men and women in motion, 27 plates of abnormal male and female movement, 16 of children, 5 of adult male hand movement, and only 221 with animal subjects. Many of the animal plates featured horses, partially a consequence of Muybridge's offering private owners to photograph their horses in exchange for a contribution to the cost of the study. Animals were typically photographed crossing a short distance, human subjects were also portrayed performing activities ranging from typical daily tasks to competitive athletics.
Muybridge classified his adult male human models according to their profession, adult female models ("chosen from all classes of society") to their marital status, age and built. He described himself (model 95) as "an ex-athlete, aged about sixty".
In many cases the human images featured nude or partially-nude men or women, directly confronting a local controversy over the use of nude models in art.
Reception
Muybridge's Animal Locomotion project received attention in the news, who reported on his unusual character and eccentricities as well as the photographic project. The collection's portrayal of nude subjects has been the focus of a directed scholarly study.
Although conceived and initially received as a scientific study, historians note that many of the plates of Animal Locomotion seem to have little to do with science. While most of the male subjects engage in sports or physical labor, most of the movements of female subjects were accessorized with props to create a more imaginative setting, relating to the gendered traditions of 19th century culture. Many of the plates aren't the objective records that were suggested by the use of a chronograph and a background grid; Muybridge was more concerned with esthetics and thus cropped the images, freely omitted elements of a sequence, or combined pictures from different takes.
Legacy
Historians and theoreticians have proposed that Muybridge's work on animal locomotion influenced a number of other artists, photographers and filmmakers, including Marcel Duchamp, Thomas Eakins, Walt Disney, among others.
The composer Philip Glass created a three-part chamber opera titled The Photographer in 1982 that featured a slide show of the motion studies in the second act.
The conceptual artist, Sol LeWitt was inspired by the serial nature of the Animal Locomotion studies, and produced works that directly refers to it.
Poet and legendary singer Jim Morrison wrote about the project in his bundle The Lords and New Creatures (1970): "Muybridge derived his animal subjects from the Philadelphia Zoological Garden, male performers from the University. The women were professional artists’ models, also actresses and dancers, parading nude before the 48 cameras."
In 1992, the Addison Gallery of American Art produced the exhibition, Motion and Document–Sequence and Time: Eadweard Muybridge and Contemporary American Photography, pairing Muybridge's animal motion studies with the work of 42 artists and photographers among them Vito Acconci and Sarah Charlesworth. The show later traveled to the Long Beach Museum of Art.
An animation of one of the Animal Locomotion horse plates was used for a Google doodle on April 9, 2012, to commemorate the 182nd anniversary of Muybridge's birthday.
An animation of Muybridge's pictures of galloping horse Annie G. (plate 626) was featured in Jordan Peele's 2022 science fiction horror film Nope. In the film, Keke Palmer's character Emerald "Em" Haywood claims that she, her brother OJ Haywood (Daniel Kaluuya) and their father are direct descendants of the rider in the photographs. The animation was also featured briefly in Back to the Future: The Game, made by Telltale.
Collections
The University of Pennsylvania houses the Muybridge Collection, which contains 740 of the 781 plates, along with some of his photographic equipment. Images from the series are held in numerous permanent collections including the Royal Academy of Arts, Pennsylvania Academy of Fine Arts, the Metropolitan Museum, the Brooklyn Museum, the Museum of Modern Art and others.
Gallery
References
Further reading
Hendricks, G. Eadweard Muybridge: The Father of the Motion Picture (London: Secker and Warburg, 1975)
Muybridge, Eadweard. Muybridge's Complete Human and Animal Locomotion, Vol. I: All 781 Plates from the 1887 "Animal Locomotion" (1979) Dover Publications
Muybridge, Eadweard. Descriptive Zoopraxography, or the Science of Animal Locomotion Made Popular (1893) Library of Alexandria.
Solnit, Rebecca. Motion Studies: Time, Space and Eadweard Muybridge (London: Bloomsbury, 2004)
External links
Animal locomotion : an electro-photographic investigation of consecutive phases of animal movements Prospectus and Catalog of Plates
Animals in motion: an electro-photographic investigation of consecutive phases of animal progressive movements, 1899 Digital copy by Mart museum, Italy
Eadweard Muybridge Collection, at the University of Pennsylvania
1887 films
1887 works
1887 in film
1880s photographs
1887 short films
History of photography
Photographic collections
1880s in American cinema
Animal locomotion
Stop motion
1880s in animation
Films directed by Eadweard Muybridge
Surviving American silent films | Animal Locomotion | Physics,Biology | 2,562 |
1,456,863 | https://en.wikipedia.org/wiki/Setpoint%20%28control%20system%29 | In cybernetics and control theory, a setpoint (SP; also set point) is the desired or target value for an essential variable, or process value (PV) of a control system, which may differ from the actual measured value of the variable. Departure of such a variable from its setpoint is one basis for error-controlled regulation using negative feedback for automatic control. A setpoint can be any physical quantity or parameter that a control system seeks to regulate, such as temperature, pressure, flow rate, position, speed, or any other measurable attribute.
In the context of PID controller, the setpoint represents the reference or goal for the controlled process variable. It serves as the benchmark against which the actual process variable (PV) is continuously compared. The PID controller calculates an error signal by taking the difference between the setpoint and the current value of the process variable. Mathematically, this error is expressed as:
where is the error at a given time , is the setpoint, is the process variable at time .
The PID controller uses this error signal to determine how to adjust the control output to bring the process variable as close as possible to the setpoint while maintaining stability and minimizing overshoot.
Examples
Cruise control
The error can be used to return a system to its norm. An everyday example is the cruise control on a road vehicle; where external influences such as gradients cause speed changes (PV), and the driver also alters the desired set speed (SP). The automatic control algorithm restores the actual speed to the desired speed in the optimum way, without delay or overshoot, by altering the power output of the vehicle's engine. In this way the error is used to control the PV so that it equals the SP. A widespread of error is classically used in the PID controller.
Industrial applications
Special consideration must be given for engineering applications. In industrial systems, physical or process restraints may limit the determined set point. For example, a reactor which operates more efficiently at higher temperatures may be rated to withstand 500°C. However, for safety reasons, the set point for the reactor temperature control loop would be well below this limit, even if this means the reactor is running less efficiently.
See also
Process control
Proportional–integral–derivative controller
References
Classical control theory
Control devices
Control engineering
Control loop theory
Cybernetics
Process engineering | Setpoint (control system) | Engineering | 483 |
14,428,201 | https://en.wikipedia.org/wiki/GPR143 | G-protein coupled receptor 143, also known as Ocular albinism type 1 (OA1) in humans, is a conserved integral membrane protein with seven transmembrane domains and similarities with G protein-coupled receptors (GPCRs) that is expressed in the eye and epidermal melanocytes. This protein encoded by the GPR143 gene, whose variants can lead to Ocular albinism type 1.
The GPR143 gene is regulated by the Microphthalmia-associated transcription factor.
L-DOPA is an endogenous ligand for OA1.
Interactions
GPR143 has been shown to interact with GNAI1.
References
Further reading
External links
GeneReviews/NCBI/NIH/UW entry on Ocular Albinism, X-Linked
G protein-coupled receptors | GPR143 | Chemistry | 172 |
24,445,978 | https://en.wikipedia.org/wiki/AV.link | AV.link, also known under the trade names nexTViewLink, SmartLink, Q-Link, EasyLink, etc., is a protocol to carry control information between audio-visual devices connected via the SCART (EIA Multiport) connector.
It is standardised as CENELEC EN 50157-1.
The Consumer Electronics Control (CEC) communication channel in HDMI and PDMI is based on AV.link.
Electrical characteristics
AV.Link uses a single wire in an open collector configuration. It is passively pulled up to 3 or 3.3 V, and may be pulled down by any device on the bus. Total bus capacitance is a maximum of 7300 pF (ten devices at 100 pF each, plus nine cables at 700 pF), and signal transitions are correspondingly slow: 333 bit/s, with 50 μs fall time and 250 μs rise time.
Each bit transferred begins with a falling edge. The duration of the low period determines the value.
Data bits are 2.4±0.35 ms long, with 1 bits having a low period of 0.6±0.2 ms, and 0 bits having a low period of 1.5±0.2 ms. Receivers observe the data line at 1.05±0.2 ms after the falling edge to determine the bit's value.
Every message begins with a special start bit, 4.5±0.2 ms long, with a low period of 3.7±0.2 ms.
A transmitter must listen to the bus as it transmits; the receiver may hold it low, turning a transmitted 1 bit into a 0 bit. This is done, for example, to acknowledge a transmission.
If a receiver detects an error in the received data, it holds the bus low for 3.6±0.24 ms; this causes the transmitter to abort the message and retry from the beginning.
A message consists of a start bit, followed by a series of data bytes. Each byte is actually transmitted as 10 bits:
8 data bits, most significant bit first,
An end-of-message bit is 0 to indicate that more bytes are being transmitted, or 1 to indicate not, and
An acknowledge bit is transmitted as 1, but overwritten to a 0 bit by the receiver to acknowledge receipt.
For broadcast messages, the acknowledge bit is inverted: it is overwritten to 0 if any receiver rejects the message.
Each message begins with an address byte specifying the 4-bit initiator and recipient addresses. If two initiators begin transmitting at the same time, one of them will transmit a 0 bit while the other transmits a 1 bit, and the latter will observe the conflict and cease transmitting until the bus is idle again. (Note that it must be prepared for the case that the incoming message is addressed to it.)
An address byte sent with EOM=1 is a simple "ping" to check if the addressed device exists and is powered on. Otherwise, it is followed by an opcode byte, and parameters as required by the opcode.
When a device is powered on, it chooses an address and sends a ping to see if that address is claimed by another device. If no acknowledge is received, the address is free and may be kept. Otherwise, the device tries another address.
See also
Consumer Electronics Control
References
Designing CEC into your next HDMI Product
HDMI Specification Version 1.3a, Supplement 1: Consumer Electronics Control (CEC)
Audiovisual connectors
Television technology | AV.link | Technology | 725 |
58,982,979 | https://en.wikipedia.org/wiki/Strand%20sort | Strand sort is a recursive sorting algorithm that sorts items of a list into increasing order. It has worst-case time complexity, which occurs when the input list is reverse sorted. It has a best-case time complexity of , which occurs when the input is already sorted.
The algorithm first moves the first element of a list into a sub-list. It then compares the last element in the sub-list to each subsequent element in the original list. Once there is an element in the original list that is greater than the last element in the sub-list, the element is removed from the original list and added to the sub-list. This process continues until the last element in the sub-list is compared to the remaining elements in the original list. The sub-list is then merged into a new list. Repeat this process and merge all sub-lists until all elements are sorted. This algorithm is called strand sort because there are strands of sorted elements within the unsorted elements that are removed one at a time. This algorithm is also used in J Sort for fewer than 40 elements.
Example
This example is based on the description of the algorithm provided in the book IT Enabled Practices and Emerging Management Paradigms.
Step 1: Start with a list of numbers: {5, 1, 4, 2, 0, 9, 6, 3, 8, 7}.
Step 2: Next, move the first element of the list into a new sub-list: sub-list contains {5}.
Step 3: Then, iterate through the original list and compare each number to 5 until there is a number greater than 5.
1 < 5, so 1 is not added to the sub-list.
4 < 5, so 4 is not added to the sub-list.
2 < 5, so 2 is not added to the sub-list.
0 < 5, so 0 is not added to the sub-list.
9 > 5, so 9 is added to the sub-list and removed from the original list.
Step 4: Now compare 9 with the remaining elements in the original list until there is a number greater than 9.
6 < 9, so 6 is not added to the sub-list.
3 < 9, so 3 is not added to the sub-list.
8 < 9, so 8 is not added to the sub-list.
7 < 9, so 7 is not added to the sub-list.
Step 5: Now there are no more elements to compare 9 to, so merge the sub-list into a new list, called solution-list.
After step 5, the original list contains {1, 4, 2, 0, 6, 3, 8, 7}.
The sub-list is empty, and the solution list contains {5, 9}.
Step 6: Move the first element of the original list into sub-list: sub-list contains {1}.
Step 7: Iterate through the original list and compare each number to 1 until there is a number greater than 1.
4 > 1, so 4 is added to the sub-list and 4 is removed from the original list.
Step 8: Now compare 4 with the remaining elements in the original list until there is a number greater than 4.
2 < 4, so 2 is not added to the sub-list.
0 < 4, so 0 is not added to the sub-list.
6 > 4, so 6 is added to the sub-list and is removed from the original list.
Step 9: Now compare 6 with the remaining elements in the original list until there is a number greater than 6.
3 < 6, so 3 is not added to the sub-list.
8 > 6, so 8 is added to the sub-list and is removed from the original list.
Step 10: Now compare 8 with the remaining elements in the original list until there is a number greater than 8.
7 < 8, so 7 is not added to the sub-list.
Step 11: Since there are no more elements in the original list to compare {8} to, the sub-list is merged with the solution list. Now the original list contains {2, 0, 3, 7}, the sub-list is empty, and the solution-list contains {1, 4, 5, 6, 8, 9}.
Step 12: Move the first element of the original list into sub-list. Sub-list contains {2}.
Step 13: Iterate through the original list and compare each number to 2 until there is a number greater than 2.
0 < 2, so 0 is not added to the sub-list.
3 > 2, so 3 is added to the sub-list and is removed from the original list.
Step 14: Now compare 3 with the remaining elements in the original list until there is a number greater than 3.
7 > 3, so 7 is added to the sub-list and is removed from the original list.
Step 15: Since there are no more elements in the original list to compare {7} to, the sub-list is merged with the solution list. The original list now contains {0}, the sub-list is empty, and solution list contains {1, 2, 3, 4, 5, 6, 7, 8, 9}.
Step 16: Move the first element of the original list into sub-list. Sub-list contains {0}.
Step 17: Since the original list is now empty, the sub-list is merged with the solution list. The solution list now contains {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}. There are now no more elements in the original list, and all of the elements in the solution list have successfully been sorted into increasing numerical order.
Implementation
Since Strand Sort requires many insertions and deletions, it is best to use a linked list when implementing the algorithm. Linked lists require constant time for both insertions and removals of elements using iterators. The time to traverse through the linked list is directly related to the input size of the list. The following implementation is done in Java 8 and is based on the description of the algorithm from the book IT Enabled Practices and Emerging Management Paradigms.package strandSort;
import java.util.*;
public class strandSort {
static LinkedList<Integer> solList = new LinkedList<Integer>();
static int k = 0;
/**
* This is a recursive Strand Sort method. It takes in a linked list of
* integers as its parameter. It first checks the base case to see if the
* linked list is empty. Then proceeds to the Strand sort algorithm until
* the linked list is empty.
*
* @param origList:
* a linked list of integers
*/
public static void strandSortIterative(LinkedList<Integer> origList) {
// Base Case
if (origList.isEmpty()) {
return;
}
else {
// Create the subList and add the first element of
// The original linked list to the sublist.
// Then remove the first element from the original list.
LinkedList<Integer> subList = new LinkedList<Integer>();
subList.add(origList.getFirst());
origList.removeFirst();
// Iterate through the original list, checking if any elements are
// Greater than the element in the sub list.
int index = 0;
for (int j = 0; j < origList.size(); j++) {
if (origList.get(j) > subList.get(index)) {
subList.add(origList.get(j));
origList.remove(j);
j = j - 1;
index = index + 1;
}
}
// Merge sub-list into solution list.
// There are two cases for this step/
// Case 1: The first recursive call, add all of the elements to the
// solution list in sequential order
if (k == 0) {
for (int i = 0; i < subList.size(); i++) {
solList.add(subList.get(i));
k = k + 1;
}
}
// Case 2: After the first recursive call,
// merge the sub-list with the solution list.
// This works by comparing the greatest element in the sublist (which is always the last element)
// with the first element in the solution list.
else {
int subEnd = subList.size() - 1;
int solStart = 0;
while (!subList.isEmpty()) {
if (subList.get(subEnd) > solList.get(solStart)) {
solStart++;
} else {
solList.add(solStart, subList.get(subEnd));
subList.remove(subEnd);
subEnd--;
solStart = 0;
}
}
}
strandSortIterative(origList);
}
}
public static void main(String[] args) {
// Create a new linked list of Integers
LinkedList<Integer> origList = new LinkedList<Integer>();
// Add the following integers to the linked list: {5, 1, 4, 2, 0, 9, 6, 3, 8, 7}
origList.add(5);
origList.add(1);
origList.add(4);
origList.add(2);
origList.add(0);
origList.add(9);
origList.add(6);
origList.add(3);
origList.add(8);
origList.add(7);
strandSortIterative(origList);
// Print out the solution list
for (int i = 0; i < solList.size(); i++) {
System.out.println(solList.get(i));
}
}
}
References
Sorting algorithms | Strand sort | Mathematics | 2,118 |
1,095,275 | https://en.wikipedia.org/wiki/Cyanogen%20chloride | Cyanogen chloride is a highly toxic chemical compound with the formula CNCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide, a room-temperature solid that is widely used in biochemical analysis and preparation.
Synthesis, basic properties, structure
Cyanogen chloride is a molecule with the connectivity . Carbon and chlorine are linked by a single bond, and carbon and nitrogen by a triple bond. It is a linear molecule, as are the related cyanogen halides (NCF, NCBr, NCI). Cyanogen chloride is produced by the oxidation of sodium cyanide with chlorine. This reaction proceeds via the intermediate cyanogen ().
NaCN + Cl2 -> ClCN + NaCl
The compound trimerizes in the presence of acid to the heterocycle called cyanuric chloride.
Cyanogen chloride is slowly hydrolyzed by water at neutral pH to release cyanate and chloride ions:
ClCN + H2O -> NCO- + Cl- + 2H+
Applications in synthesis
Cyanogen chloride is a precursor to the sulfonyl cyanides and chlorosulfonyl isocyanate, a useful reagent in organic synthesis.
Further chlorination gives the isocyanide dichloride.
Safety
Also known as CK, cyanogen chloride is a highly toxic blood agent, and was once proposed for use in chemical warfare. It causes immediate injury upon contact with the eyes or respiratory organs. Symptoms of exposure may include drowsiness, rhinorrhea (runny nose), sore throat, coughing, confusion, nausea, vomiting, edema, loss of consciousness, convulsions, paralysis, and death. It is especially dangerous because it is capable of penetrating the filters in gas masks, according to United States analysts. CK is unstable due to polymerization, sometimes with explosive violence.
Chemical weapon
Cyanogen chloride is listed in schedule 3 of the Chemical Weapons Convention: all production must be reported to the OPCW.
By 1945, the U.S. Army's Chemical Warfare Service developed chemical warfare rockets intended for the new M9 and M9A1 Bazookas. An M26 Gas Rocket was adapted to fire cyanogen chloride-filled warheads for these rocket launchers. As it was capable of penetrating the protective filter barriers in some gas masks, it was seen as an effective agent against Japanese forces (particularly those hiding in caves or bunkers) because their standard issue gas masks lacked the barriers that would provide protection against cyanogen chloride. The US added the weapon to its arsenal, and considered using it, along with hydrogen cyanide, as part of Operation Downfall, the planned invasion of Japan, but President Harry Truman decided against it, instead using the atomic bombs developed by the secret Manhattan Project. The CK rocket was never deployed or issued to combat personnel.
References
External links
Chlorine compounds
Triatomic molecules
Cyano compounds
Nonmetal halides
Blood agents
Pseudohalogens | Cyanogen chloride | Physics,Chemistry | 642 |
8,903,910 | https://en.wikipedia.org/wiki/Green%20cleaning | Green cleaning refers to using cleaning methods and products with environmentally friendly ingredients and procedures which are designed to preserve human health and environmental quality. Green cleaning techniques and products avoid the use of products which contain toxic chemicals, some of which emit volatile organic compounds causing respiratory, dermatological and other conditions. Green cleaning can also describe the way residential and industrial cleaning products are manufactured, packaged and distributed. If the manufacturing process is environmentally friendly and the products are biodegradable, then the term "green" or "eco-friendly" may apply.
Product labeling programs
Among the product-labeling programs is the United States Environmental Protection Agency's (EPA) Design for the Environment program which labels products that meet the EPA's criteria for chemicals. These products are allowed to carry the Design for the Environment (DfE) label, renamed EPA Safer Choice in 2015. Generally, products which are labelled 'low' or 'zero' VOC are safer for human and animal health in the home as well as the environment. In addition, the EPA's Toxic Substances Control Act addresses chemicals in the environment and makes regulatory rules to maximize human health. There are also independent product labeling programs for cleaning products and cleaning services offered by nonprofit organizations like Green Seal.
On October 15, 2017, California Governor Jerry Brown signed into law Senate Bill 258, the Cleaning Product Right to Know Act. The bill was brought to the floor by Senator Ricardo Lara and supported by some of the oldest green cleaning manufacturers, such as Kelly Vlahakis-Hanks of Earth Friendly Products and board member of the American Sustainable Business Council, as well as mainstream companies who are entering into the green cleaning space such as SC Johnson who recently purchased Mrs. Meyers and Method. The Cleaning Product Right to Know Act makes California the first state to require ingredient labeling both on product labels and online for cleaning products. Unlike retail packaged food, no federal requirements exist for disclosing ingredients on cleaning products. The Cleaning Product Right to Know Act will require known hazardous chemicals in cleaning products to be listed on both product labels and online by 2020. The legislation lists 34 chemicals found in cleaning products that have been shown to cause cancer, birth defects, asthma and other serious health effects:
1,4-Dioxane
1,1-Dichloroethane
Acrylic acid
Benzene
Benzidine
1,3-Butadiene
Carbon tetrachloride
Chloroform
Ethylene oxide
Nitrilotriacetic acid
Butyl benzyl phthalate
Butyl decyl phthalate
Di(2-ethylhexyl) phthalate
Diethyl phthalate
Diisobutyl phthalate
Di(n-octyl) phthalate
Diisononyl phthalate
Dioctyl phthalate
Butylparaben
Ethylparaben
Isobutylparaben
Methylparaben
Propylparaben
Formaldehyde
DMDM hydantoin
Diazolidinyl urea
Glyoxal
Imidazolidinyl urea
Polyoxymethylene urea
Sodium hydroxymethylglycinate
2-Bromo-2-nitropropane-1,3-diol
N-Nitrosodimethylamine
N-Nitrosodiethylamine
1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride
In the announcement made by the California State Senate said the bill was in "response to consumers' demand for transparency."
See also
Green Seal
Cleaning agent
Environmental impact of cleaning agents
Design for the Environment
United States Environmental Protection Agency
Greenwashing
References
External links
Epa.gov
Cleaning products
Cleaning and the environment
Cleaning methods | Green cleaning | Chemistry | 759 |
41,031,824 | https://en.wikipedia.org/wiki/Numerical%20methods%20in%20fluid%20mechanics | Fluid motion is governed by the Navier–Stokes equations, a set of coupled and nonlinear
partial differential equations derived from the basic laws of conservation of mass, momentum
and energy. The unknowns are usually the flow velocity, the pressure and density and temperature. The analytical solution of this equation is impossible hence scientists resort to laboratory experiments in such situations. The answers delivered are, however, usually qualitatively different since dynamical and geometric similitude are difficult to enforce simultaneously between the lab experiment and the prototype. Furthermore, the design and construction of these experiments can be difficult (and costly), particularly for stratified rotating flows. Computational fluid dynamics (CFD) is an additional tool in the arsenal of scientists. In its early days CFD was often controversial, as it involved additional approximation to the governing equations and raised additional (legitimate) issues. Nowadays CFD is an established discipline alongside theoretical and experimental methods. This position is in large part due to the exponential growth of computer power which has allowed us to tackle ever larger and more complex problems.
Discretization
The central process in CFD is the process of discretization, i.e. the process of taking differential equations with an infinite number of degrees of freedom, and reducing it to a system of finite degrees of freedom. Hence, instead of determining the solution everywhere and for all times, we will be satisfied with its calculation at a finite number of locations and at specified time intervals. The partial differential equations are then reduced to a system of algebraic equations that can be solved on a computer. Errors creep in during the discretization process. The nature and characteristics of the errors must be controlled in order to ensure that:
we are solving the correct equations (consistency property)
that the error can be decreased as we increase the number of degrees of freedom (stability and convergence).
Once these two criteria are established, the power of computing machines can be leveraged to solve the problem in a numerically reliable fashion. Various discretization schemes have been developed to cope with a variety of issues. The most notable for our purposes are: finite difference methods, finite volume methods, finite element methods, and spectral methods.
Finite difference method
Finite difference replace the infinitesimal limiting process of derivative calculation:
with a finite limiting process, i.e.
The term gives an indication of the magnitude of the error as a function of the mesh spacing. In this instance, the error is halved if the grid spacing, _x is halved, and we say that this is a first order method. Most FDM used in practice are at least second order accurate except in very special circumstances. Finite Difference method is still the most popular numerical method for solution of PDEs because of their simplicity, efficiency and low computational cost. Their major drawback is in their geometric inflexibility which complicates their applications to general complex domains. These can be alleviated by the use of either mapping techniques and/or masking to fit the computational mesh to the computational domain.
Finite element method
The finite element method was designed to deal with problem with complicated computational regions. The PDE is first recast into a variational form which essentially forces the mean error to be small everywhere. The discretization step proceeds by dividing the computational domain into elements of triangular or rectangular shape. The solution within each element is interpolated with a polynomial of usually low order. Again, the unknowns are the solution at the collocation points. The CFD community adopted the FEM in the 1980s when reliable methods for dealing with advection dominated problems were devised.
Spectral method
Both finite element and finite difference methods are low order methods, usually of 2nd − 4th order, and have local approximation property. By local we mean that a particular collocation point is affected by a limited number of points around it. In contrast, spectral method have global approximation property. The interpolation functions, either polynomials or trigonomic functions are global in nature. Their main benefits is in the rate of convergence which depends on the smoothness of the solution (i.e. how many continuous derivatives does it admit). For infinitely smooth solution, the error decreases exponentially, i.e. faster than algebraic. Spectral methods are mostly used in the computations of homogeneous turbulence, and require relatively simple geometries. Atmospheric model have also adopted spectral methods because of their convergence properties and the regular spherical shape of their computational domain.
Finite volume method
Finite volume methods are primarily used in aerodynamics applications where strong shocks and discontinuities in the solution occur. Finite volume method solves an integral form of the governing equations so that local continuity property do not have to hold.
Computational cost
The CPU time to solve the system of equations differs substantially from method to method. Finite differences are usually the cheapest on a per grid point basis followed by the finite element method and spectral method. However, a per grid point basis comparison is a little like comparing apple and oranges. Spectral methods deliver more accuracy on a per grid point basis than either FEM or FDM. The comparison is more meaningful if the question is recast as ”what is the computational cost to achieve a given error tolerance?”. The problem becomes one of defining the error measure which is a complicated task in general situations.
Forward Euler approximation
Equation is an explicit approximation to the original differential equation since no information about the unknown function at the future time (n + 1)t has been used on the right hand side of the equation. In order to derive the error committed in the approximation we rely again on Taylor series.
Backward difference
This is an example of an implicit method since the unknown u(n + 1) has been used in evaluating the slope of the solution on the right hand side; this is not a problem to solve for u(n + 1) in this scalar and linear case. For more complicated situations like a nonlinear right hand side or a system of equations, a nonlinear system of equations may have to be inverted.
References
Sources
Zalesak, S. T., 2005. The design of flux-corrected transport algorithms for structured grids. In: Kuzmin, D., Löhner, R., Turek, S. (Eds.), Flux-Corrected Transport. Springer
Zalesak, S. T., 1979. Fully multidimensional flux-corrected transport algorithms for fluids. Journal of Computational Physics.
Leonard, B. P., MacVean, M. K., Lock, A. P., 1995. The flux integral method for multi-dimensional convection and diffusion. Applied Mathematical Modelling.
Shchepetkin, A. F., McWilliams, J. C., 1998. Quasi-monotone advection schemes based on explicit locally adaptive dissipation. Monthly Weather Review
Jiang, C.-S., Shu, C.-W., 1996. Efficient implementation of weighed eno schemes. Journal of Computational Physics
Finlayson, B. A., 1972. The Method of Weighed Residuals and Variational Principles. Academic Press.
Durran, D. R., 1999. Numerical Methods for Wave Equations in Geophysical Fluid Dynamics. Springer, New York.
Dukowicz, J. K., 1995. Mesh effects for rossby waves. Journal of Computational Physics
Canuto, C., Hussaini, M. Y., Quarteroni, A., Zang, T. A., 1988. Spectral Methods in Fluid Dynamics. Springer Series in Computational Physics. Springer-Verlag, New York.
Butcher, J. C., 1987. The Numerical Analysis of Ordinary Differential Equations. John Wiley and Sons Inc., NY.
Boris, J. P., Book, D. L., 1973. Flux corrected transport, i: Shasta, a fluid transport algorithm that works. Journal of Computational Physics
Citations
Computational fluid dynamics
Numerical analysis
Functional analysis | Numerical methods in fluid mechanics | Physics,Chemistry,Mathematics | 1,608 |
73,384,654 | https://en.wikipedia.org/wiki/Chessboard%20complex | A chessboard complex is a particular kind of abstract simplicial complex, which has various applications in topological graph theory and algebraic topology. Informally, the (m, n)-chessboard complex contains all sets of positions on an m-by-n chessboard, where rooks can be placed without attacking each other. Equivalently, it is the matching complex of the (m, n)-complete bipartite graph, or the independence complex of the m-by-n rook's graph.
Definitions
For any two positive integers m and n, the (m, n)-chessboard complex is the abstract simplicial complex with vertex set that contains all subsets S such that, if and are two distinct elements of S, then both and . The vertex set can be viewed as a two-dimensional grid (a "chessboard"), and the complex contains all subsets S that do not contain two cells in the same row or in the same column. In other words, all subset S such that rooks can be placed on them without taking each other.
The chessboard complex can also be defined succinctly using deleted join. Let Dm be a set of m discrete points. Then the chessboard complex is the n-fold 2-wise deleted join of Dm, denoted by .
Another definition is the set of all matchings in the complete bipartite graph .
Examples
In any (m,n)-chessboard complex, the neighborhood of each vertex has the structure of a (m − 1,n − 1)-chessboard complex. In terms of chess rooks, placing one rook on the board eliminates the remaining squares in the same row and column, leaving a smaller set of rows and columns where additional rooks can be placed. This allows the topological structure of a chessboard to be studied hierarchically, based on its lower-dimensional structures. An example of this occurs with the (4,5)-chessboard complex, and the (3,4)- and (2,3)-chessboard complexes within it:
The (2,3)-chessboard complex is a hexagon, consisting of six vertices (the six squares of the chessboard) connected by six edges (pairs of non-attacking squares).
The (3,4)-chessboard complex is a triangulation of a torus, with 24 triangles (triples of non-attacking squares), 36 edges, and 12 vertices. Six triangles meet at each vertex, in the same hexagonal pattern as the (2,3)-chessboard complex.
The (4,5)-chessboard complex forms a three-dimensional pseudomanifold: in the neighborhood of each vertex, 24 tetrahedra meet, in the pattern of a torus, instead of the spherical pattern that would be required of a manifold. If the vertices are removed from this space, the result can be given a geometric structure as a cusped hyperbolic 3-manifold, topologically equivalent to the link complement of a 20-component link.
Properties
Every facet of contains elements. Therefore, the dimension of is .
The homotopical connectivity of the chessboard complex is at least (so ).
The Betti numbers of chessboard complexes are zero if and only if . The eigenvalues of the combinatorial Laplacians of the chessboard complex are integers.
The chessboard complex is -connected, where . The homology group is a 3-group of exponent at most 9, and is known to be exactly the cyclic group on 3 elements when .
The -skeleton of chessboard complex is vertex decomposable in the sense of Provan and Billera (and thus shellable), and the entire complex is vertex decomposable if . As a corollary, any position of k rooks on a m-by-n chessboard, where , can be transformed into any other position using at most single-rook moves (where each intermediate position is also not rook-taking).
Generalizations
The complex is a "chessboard complex" defined for a k-dimensional chessboard. Equivalently, it is the set of matchings in a complete k-partite hypergraph. This complex is at least -connected, for
References
Topological graph theory | Chessboard complex | Mathematics | 887 |
63,239,548 | https://en.wikipedia.org/wiki/IBM%20ThinkPad%20570 | The IBM ThinkPad 570 is a notebook series from the ThinkPad line by IBM.
Models
Comparison
References
External links
Thinkwiki.de - 570
ThinkPad 570
570
Computer-related introductions in 1999 | IBM ThinkPad 570 | Technology | 41 |
17,344,326 | https://en.wikipedia.org/wiki/Omar%20M.%20Yaghi | Omar M. Yaghi (; born February 9, 1965) is the James and Neeltje Tretter Chair Professor of Chemistry at the University of California, Berkeley, an affiliate scientist at Lawrence Berkeley National Laboratory, the founding director of the Berkeley Global Science Institute, and an elected member of the US National Academy of Sciences as well as the German National Academy of Sciences Leopoldina.
Early life and education
Yaghi was born in Amman, Jordan, in 1965, to a refugee family originally from Mandatory Palestine. He grew up in a household with many children, had limited access to clean water and without electricity. At the age of 15, he moved to the United States at the encouragement of his father. Although he knew little English, he began classes at Hudson Valley Community College, and later transferred to the University at Albany, SUNY, to finish his college degree. He began his graduate studies at University of Illinois, Urbana-Champaign, and received his PhD in 1990 under the guidance of Walter G. Klemperer. He was a National Science Foundation postdoctoral fellow at Harvard University (1990–1992) with Richard H. Holm. In 2021, Yaghi was granted Saudi citizenship.
Academic career
He was on the faculties of Arizona State University (1992–1998) as an assistant professor, the University of Michigan (1999–2006) as the Robert W. Parry Professor of Chemistry, and the University of California, Los Angeles (2007–2012) as the Christopher S. Foote Professor of Chemistry as well as holding the Irving and Jean Stone Chair in Physical Sciences.
In 2012, he moved to the University of California, Berkeley, where he is now the James and Neeltje Tretter Professor of Chemistry. He was the director of the Molecular Foundry at Lawrence Berkeley National Laboratory from 2012 through 2013. He is the Founding Director of the Berkeley Global Science Institute. He is also a co-director of the Kavli Energy NanoSciences Institute of the University of California, Berkeley, and the Lawrence Berkeley National Laboratory, the California Research Alliance by BASF, as well as the Bakar Institute of Digital Materials for the Planet.
Research
Reticular chemistry
Yaghi pioneered reticular chemistry, a new field of chemistry concerned with stitching molecular building blocks together by strong bonds to make open frameworks. As stated by the International Balzan Prize Foundation, Omar Yaghi suggested the idea of using molecular building blocks and strong bonds to form crystalline materials in the early 1990s. At the time, the scientific community considered this idea chemically unfeasible, as the synthesis of strong bonding between molecular components usually led to poorly defined, amorphous solids. However, in 1995, Yaghi successfully crystallized metal-organic structures where metal ions are joined by charged organic linkers as exemplified by carboxylates to form strong bonds. This discovery paved the way for the development of a new class of materials: Metal-Organic Frameworks (MOFs), and thus it marked the start of reticular chemistry.
Metal-organic frameworks
His most recognizable work is in the design, synthesis, application, and popularisation of metal-organic frameworks (MOFs). By IUPAC recommendation, MOF is considered a subclass of the coordination polymers first reported in 1959 by Yoshihiko Saito and colleagues. This is followed by E. A. Tomic in 1965 when he published a report titled "Thermal stability of coordination polymers" where he synthesized and characterized many coordination polymers constructed with different ligands and various metal ions. Hans-Peter Werner and colleagues in 1986 published a coordination polymer 2,5-Dimethyl-N,N′-dicyanoquinonediimine and evaluated its electrical conductivity, and in 1989 Bernard Hoskins and Richard Robson reported a coordination polymer consisting of three dimensionally linked rod-like segments. In general, coordination polymers are frail disordered structures with poorly defined properties.
In the 1990s, Omar M. Yaghi made three breakthroughs that transformed the traditional coordination polymers into architecturally robust and permanently porous MOFs which are being widely used today: (1) crystallization of metal-organic structures where metal ions are joined by charged organic linkers as exemplified by carboxylates to form strong bonds (published in 1995); (2) introduction of metal-carboxylate clusters as secondary building units (SBUs), which was the key to building architecturally robust frameworks exhibiting permanent porosity as he proved by measuring for the first time their gas adsorption isotherms (published in 1998); (3) realization of ultra-high porosity with MOF-5 (published in 1999). In essence, the strong bonds holding the MOFs allow for their structural robustness, ultra-high porosity, and longevity in industrial applications.
Covalent organic frameworks
Omar M. Yaghi published the first paper of covalent organic frameworks (COFs) in 2005, reporting a series of 2D COFs. He reported the design and successful synthesis of COFs by condensation reactions of phenyl diboronic acid (C6H4[B(OH)2]2) and hexahydroxytriphenylene (C18H6(OH)6). Powder X-ray diffraction studies of the highly crystalline products having empirical formulas (C3H2BO)6·(C9H12)1 (COF-1) and C9H4BO2 (COF-5) revealed 2-dimensional expanded porous graphitic layers that have either staggered conformation (COF-1) or eclipsed conformation (COF-5). Their crystal structures are entirely held by strong bonds between B, C, and O atoms to form rigid porous architectures with pore sizes ranging from 7 to 27 angstroms. COF-1 and COF-5 exhibit high thermal stability (to temperatures up to 500 to 600 °C), permanent porosity, and high surface areas (711 and 1590 square meters per gram, respectively). The synthesis of 3D COFs has been hindered by longstanding practical and conceptual challenges until it was first achieved in 2007 by Omar M. Yaghi.
Yaghi is also known for the design and production of a new class of compounds known as zeolitic imidazolate frameworks (ZIFs). MOFs, COFs, ZIFs are noted for their extremely high surface areas ( for MOF-177) and very low crystalline densities ( for COF-108).
Molecular weaving
Yaghi also pioneered molecular weaving, and synthesized the world's first material woven at the atomic and molecular levels (COF-505).
He has been leading the effort in applying these materials in clean energy technologies including hydrogen and methane storage, carbon dioxide capture and storage, as well as harvesting water from desert air.
According to a Thomson Reuters analysis, Yaghi was the second most cited chemist in the world from 2000 to 2010.
Entrepreneurship
In 2020, Yaghi founded Atoco, a California-based startup, aiming to commercialize the latest advancements and discoveries by Yaghi in MOFs and COFs technologies in the field of carbon capture and atmospheric water harvesting.
In 2021, Yaghi co-founded another startup called H2MOF, dedicated to solving the challenges associated with hydrogen storage by utilizing the latest discoveries by Yaghi in the field of reticular chemistry.
Honors and awards
Yaghi has received several global awards and medals throughout his career, including the Albert Einstein World Award of Science in 2017; the Wolf Prize in Chemistry in 2018; the Gregory Aminoff Prize in 2019; the VinFuture Prize in 2022, and the Science for the Future Ernest Solvay Prize in 2024. The following are among the key awards, medals and recognitions Yaghi received:
1998 Solid State Chemistry Award of the American Chemical Society and Exxon Co. for his accomplishments in the design and synthesis of new materials
2004 Sacconi Medal of the Italian Chemical Society
2007 US Department of Energy Hydrogen Program Award for his work on hydrogen storage
2007 Materials Research Society Medal for his work in the theory, design, synthesis and applications of metal-organic frameworks
2007 Newcomb Cleveland Prize of the American Association for the Advancement of Science for the best paper published in Science
2009 American Chemical Society Chemistry of Materials Award
2009 Izatt-Christensen International Award
2010 Royal Society of Chemistry Centenary Prize
2013 China Nano Award
2015 King Faisal International Prize in Chemistry
2015 Mustafa Prize in Nanoscience and Nanotechnology
2016 TÜBA Academy Prize in Basic and Engineering Sciences for establishing Reticular Chemistry
2017 Spiers Memorial Award from the Royal Society of Chemistry
2017 Medal of Excellence of the First Order bestowed by King Abdullah II
2017 Japan Society of Coordination Chemistry International Award
2017 Bailar Medal in Inorganic Chemistry
2017 Kuwait Prize in Fundamental Sciences
2017 Albert Einstein World Award of Science conferred by the World Cultural Council
2018 BBVA Foundation Frontiers of Knowledge Award in Basic Sciences for pioneering Reticular Chemistry
2018 Wolf Prize in Chemistry for pioneering reticular chemistry via metal-organic frameworks and covalent organic frameworks
2018 his work on water harvesting from desert air using metal-organic frameworks showcased by the World Economic Forum in Switzerland as one of the top 10 emerging technologies
2018 Prince Sultan bin Abdulaziz International Prize for Water
2018 Eni Award in recognition of his work in applying framework chemistry to clean energy solutions including methane storage, carbon dioxide capture and conversion, and water harvesting from desert air
2019 Gregori Aminoff Prize by the Royal Swedish Academy of Sciences for the development of reticular chemistry
2019 MBR Medal for Scientific Excellence of the United Arab Emirates
2019 Nano Research Award
2020 August-Wilhelm-von-Hofmann-Denkmünze gold medal of the German Chemical Society for his contribution to reticular chemistry and for pioneering MOFs, COFs, and molecular weaving
2020 Royal Society of Chemistry Sustainable Water Award for his impactful development of water harvesting from desert air using metal–organic frameworks
2021 Belgium's International Solvay Chair in Chemistry
2021 Ertl Lecture Award by the Fritz Haber Institute of the Max Planck Society and Berlin universities
2022 VinFuture Prize for Outstanding Achievements in Emerging Fields in recognition of his pioneering Reticular Chemistry
2023 Wilhelm Exner Medal of Austria for his direct impact on business and industry through his scientific achievements
2024 Science for the Future Ernest Solvay Prize of Belgium in recognition of his pioneering work in reticular chemistry
2024 Tang Prize in sustainable development for his work in reticular chemistry
2024 Ullyot Public Affairs Lecture and Award of the Science History Institute
2024 Balzan Prize for Nanoporous Materials for Environmental Applications for his pioneering MOFs and COFs
2025 The Great Arab Minds Award
References
External links
The Yaghi Group website.
Yaghi CV
Omar M. Yaghi – Google Scholar Citations.
MOFs are the most beautiful compounds ever made
Omar M. Yaghi Lecture – Reticular Chemistry
Omar M. Yaghi Lecture – Harvesting water from desert air
1965 births
Living people
Albert Einstein World Award of Science Laureates
Jordanian people of Palestinian descent
American people of Palestinian descent
Inorganic chemists
Jordanian chemists
21st-century American chemists
People from Amman
UC Berkeley College of Chemistry faculty
University of Illinois Urbana-Champaign alumni
University at Albany, SUNY alumni
Arizona State University faculty
University of Michigan faculty
Wolf Prize in Chemistry laureates
Jordanian emigrants to the United States
Solid state chemists | Omar M. Yaghi | Chemistry | 2,319 |
9,032 | https://en.wikipedia.org/wiki/Drosophila | Drosophila () is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly.
One species of Drosophila in particular, Drosophila melanogaster, has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "Drosophila" are often used synonymously with D. melanogaster in modern biological literature. The entire genus, however, contains more than 1,500 species and is very diverse in appearance, behavior, and breeding habitat.
Etymology
The term "Drosophila", meaning "dew-loving", is a modern scientific Latin adaptation from Greek words , , "dew", and , , "lover".
Morphology
Drosophila species are small flies, typically pale yellow to reddish brown to black, with red eyes. When the eyes (essentially a film of lenses) are removed, the brain is revealed. Drosophila brain structure and function develop and age significantly from larval to adult stage. Developing brain structures make these flies a prime candidate for neuro-genetic research. According to a study published in Nature in October 2024, by the scientists examining the brain of an adult female Drosophila, the shape and location of each of its 130,000 neurons and 50 million synapsis were identified. In this study, the most detailed analysis ever conducted on the brain of an adult animal is represented. Many species, including the noted Hawaiian picture-wings, have distinct black patterns on the wings. The plumose (feathery) arista, bristling of the head and thorax, and wing venation are characters used to diagnose the family. Most are small, about long, but some, especially many of the Hawaiian species, are larger than a house fly.
Evolution
Detoxification mechanisms
Environmental challenge by natural toxins helped to prepare Drosophilae to detox DDT, by shaping the glutathione S-transferase mechanism that metabolizes both.
Selection
The Drosophila genome is subject to a high degree of selection, especially unusually widespread negative selection compared to other taxa. A majority of the genome is under selection of some sort, and a supermajority of this is occurring in non-coding DNA.
Effective population size has been credibly suggested to positively correlate with the effect size of both negative and positive selection. Recombination is likely to be a significant source of diversity. There is evidence that crossover is positively correlated with polymorphism in D. populations.
Biology
Habitat
Drosophila species are found all around the world, with more species in the tropical regions. Drosophila made their way to the Hawaiian Islands and radiated into over 800 species. They can be found in deserts, tropical rainforest, cities, swamps, and alpine zones. Some northern species hibernate. The northern species D. montana is the best cold-adapted, and is primarily found at high altitudes. Most species breed in various kinds of decaying plant and fungal material, including fruit, bark, slime fluxes, flowers, and mushrooms. Drosophila species that are fruit-breeding are attracted to various products of fermentation, especially ethanol and methanol. Fruits exploited by Drosophila species include those with a high pectin concentration, which is an indicator of how much alcohol will be produced during fermentation. Citrus, morinda, apples, pears, plums, and apricots belong into this category.
The larvae of at least one species, D. suzukii, can also feed in fresh fruit and can sometimes be a pest. A few species have switched to being parasites or predators. Many species can be attracted to baits of fermented bananas or mushrooms, but others are not attracted to any kind of baits. Males may congregate at patches of suitable breeding substrate to compete for the females, or form leks, conducting courtship in an area separate from breeding sites.
Several Drosophila species, including Drosophila melanogaster, D. immigrans, and D. simulans, are closely associated with humans, and are often referred to as domestic species. These and other species (D. subobscura, and from a related genus Zaprionus indianus) have been accidentally introduced around the world by human activities such as fruit transports.
Reproduction
Males of this genus are known to have the longest sperm cells of any studied organism on Earth, including one species, Drosophila bifurca, that has sperm cells that are long. The cells mostly consist of a long, thread-like tail, and are delivered to the females in tangled coils. The other members of the genus Drosophila also make relatively few giant sperm cells, with that of D. bifurca being the longest. D. melanogaster sperm cells are a more modest 1.8 mm long, although this is still about 35 times longer than a human sperm. Several species in the D. melanogaster species group are known to mate by traumatic insemination.
Drosophila species vary widely in their reproductive capacity. Those such as D. melanogaster that breed in large, relatively rare resources have ovaries that mature 10–20 eggs at a time, so that they can be laid together on one site. Others that breed in more-abundant but less nutritious substrates, such as leaves, may only lay one egg per day. The eggs have one or more respiratory filaments near the anterior end; the tips of these extend above the surface and allow oxygen to reach the embryo. Larvae feed not on the vegetable matter itself, but on the yeasts and microorganisms present on the decaying breeding substrate. Development time varies widely between species (between 7 and more than 60 days) and depends on the environmental factors such as temperature, breeding substrate, and crowding.
Fruit flies lay eggs in response to environmental cycles. Eggs laid at a time (e.g., night) during which likelihood of survival is greater than in eggs laid at other times (e.g., day) yield more larvae than eggs that were laid at those times. Ceteris paribus, the habit of laying eggs at this 'advantageous' time would yield more surviving offspring, and more grandchildren, than the habit of laying eggs during other times. This differential reproductive success would cause D. melanogaster to adapt to environmental cycles, because this behavior has a major reproductive advantage.
Their median lifespan is 35–45 days.
Aging
DNA damage accumulates in Drosophila intestinal stem cells with age. Deficiencies in the Drosophila DNA damage response, including deficiencies in expression of genes involved in DNA damage repair, accelerates intestinal stem cell (enterocyte) aging. Sharpless and Depinho reviewed evidence that stem cells undergo intrinsic aging and speculated that stem cells grow old, in part, as a result of DNA damage.
Mating systems
Courtship behavior
The following section is based on the following Drosophila species: Drosophila simulans and Drosophila melanogaster.
Courtship behavior of male Drosophila is an attractive behaviour. Females respond via their perception of the behavior portrayed by the male. Male and female Drosophila use a variety of sensory cues to initiate and assess courtship readiness of a potential mate. The cues include the following behaviours: positioning, pheromone secretion, following females, making tapping sounds with legs, singing, wing spreading, creating wing vibrations, genitalia licking, bending the stomach, attempt to copulate, and the copulatory act itself. The songs of Drosophila melanogaster and Drosophila simulans have been studied extensively. These luring songs are sinusoidal in nature and varies within and between species.
The courtship behavior of Drosophila melanogaster has also been assessed for sex-related genes, which have been implicated in courtship behavior in both the male and female. Recent experiments explore the role of fruitless (fru) and doublesex (dsx), a group of sex-behaviour linked genes.
The fruitless (fru) gene in Drosophila helps regulate the network for male courtship behavior; when a mutation to this gene occurs altered same sex sexual behavior in males is observed. Male Drosophila with the fru mutation direct their courtship towards other males as opposed to typical courtship, which would be directed towards females. Loss of the fru mutation leads back to the typical courtship behavior.
Pheromones
A novel class of pheromones was found to be conserved across the subgenus Drosophila in 11 desert dwelling species. These pheromones are triacylglycerides that are secreted exclusively by males from their ejaculatory bulb and transferred to females during mating. The function of the pheromones is to make the females unattractive to subsequent suitors and thus inhibit courtship by other males.
Polyandry
The following section is based on the following Drosophila species: Drosophila serrata, Drosophila pseudoobscura, Drosophila melanogaster, and Drosophila neotestacea. Polyandry is a prominent mating system among Drosophila. Females mating with multiple sex partners has been a beneficial mating strategy for Drosophila. The benefits include both pre and post copulatory mating. Pre-copulatory strategies are the behaviours associated with mate choice and the genetic contributions, such as production of gametes, that are exhibited by both male and female Drosophila regarding mate choice. Post copulatory strategies include sperm competition, mating frequency, and sex-ratio meiotic drive.
These lists are not inclusive. Polyandry among the Drosophila pseudoobscura in North America vary in their number of mating partners. There is a connection between the number of time females choose to mate and chromosomal variants of the third chromosome. It is believed that the presence of the inverted polymorphism is why re-mating by females occurs. The stability of these polymorphisms may be related to the sex-ratio meiotic drive.
However, for Drosophila subobscura, the main mating system is monandry, not normally seen in Drosophila.
Sperm competition
The following section is based on the following Drosophila species: Drosophila melanogaster, Drosophila simulans, and Drosophila mauritiana. Sperm competition is a process that polyandrous Drosophila females use to increase the fitness of their offspring. The female Drosophila has two sperm storage organs, the spermathecae and seminal receptacle, that allows her to choose the sperm that will be used to inseminate her eggs. However, some species of Drosophila have evolved to only use one or the other. Females have little control when it comes to cryptic female choice. Female Drosophila through cryptic choice, one of several post-copulatory mechanisms, which allows for the detection and expelling of sperm that reduces inbreeding possibilities. Manier et al. 2013 has categorized the post copulatory sexual selection of Drosophila melanogaster, Drosophila simulans, and Drosophila mauritiana into the following three stages: insemination, sperm storage, and fertilizable sperm. Among the preceding species there are variations at each stage that play a role in the natural selection process. This sperm competition has been found to be a driving force in the establishment of reproductive isolation during speciation.
Parthenogenesis and gynogenesis
Parthenogenesis does not occur in D. melanogaster, but in the gyn-f9 mutant, gynogenesis occurs at low frequency. The natural populations of D. mangebeirai are entirely female, making it the only obligate parthenogenetic species of Drosophila. Parthenogenesis is facultative in parthenogenetica and mercatorum.
Laboratory-cultured animals
D. melanogaster is a popular experimental animal because it is easily cultured en masse out of the wild, has a short generation time, and mutant animals are readily obtainable. In 1906, Thomas Hunt Morgan began his work on D. melanogaster and reported his first finding of a white eyed mutant in 1910 to the academic community. He was in search of a model organism to study genetic heredity and required a species that could randomly acquire genetic mutation that would visibly manifest as morphological changes in the adult animal. His work on Drosophila earned him the 1933 Nobel Prize in Medicine for identifying chromosomes as the vector of inheritance for genes. This and other Drosophila species are widely used in studies of genetics, embryogenesis, chronobiology, speciation, neurobiology, and other areas.
However, some species of Drosophila are difficult to culture in the laboratory, often because they breed on a single specific host in the wild. For some, it can be done with particular recipes for rearing media, or by introducing chemicals such as sterols that are found in the natural host; for others, it is (so far) impossible. In some cases, the larvae can develop on normal Drosophila lab medium, but the female will not lay eggs; for these it is often simply a matter of putting in a small piece of the natural host to receive the eggs.
The Drosophila Species Stock Center located at Cornell University in Ithaca, New York, maintains cultures of hundreds of species for researchers.
Use in genetic research
Drosophila is considered one of the most valuable genetic model organisms; both adults and embryos are experimental models. Drosophila is a prime candidate for genetic research because the relationship between human and fruit fly genes is very close. Human and fruit fly genes are so similar, that disease-producing genes in humans can be linked to those in flies. The fly has approximately 15,500 genes on its four chromosomes, whereas humans have about 22,000 genes among their 23 chromosomes. Thus the density of genes per chromosome in Drosophila is higher than the human genome. Low and manageable number of chromosomes make Drosophila species easier to study. These flies also carry genetic information and pass down traits throughout generations, much like their human counterparts. The traits can then be studied through different Drosophila lineages and the findings can be applied to deduce genetic trends in humans. Research conducted on Drosophila help determine the ground rules for transmission of genes in many organisms. Drosophila is a useful in vivo tool to analyze Alzheimer's disease. Rhomboid proteases were first detected in Drosophila but then found to be highly conserved across eukaryotes, mitochondria, and bacteria. Melanin's ability to protect DNA against ionizing radiation has been most extensively demonstrated in Drosophila, including in the formative study by Hopwood et al. 1985.
Microbiome
Like other animals, Drosophila is associated with various bacteria in its gut. The fly gut microbiota or microbiome seems to have a central influence on Drosophila fitness and life history characteristics. The microbiota in the gut of Drosophila represents an active current research field.
Drosophila species also harbour vertically transmitted endosymbionts, such as Wolbachia and Spiroplasma. These endosymbionts can act as reproductive manipulators, such as cytoplasmic incompatibility induced by Wolbachia or male-killing induced by the D. melanogaster Spiroplasma poulsonii (named MSRO). The male-killing factor of the D. melanogaster MSRO strain was discovered in 2018, solving a decades-old mystery of the cause of male-killing. This represents the first bacterial factor that affects eukaryotic cells in a sex-specific fashion, and is the first mechanism identified for male-killing phenotypes. Alternatively, they may protect theirs hosts from infection. Drosophila Wolbachia can reduce viral loads upon infection, and is explored as a mechanism of controlling viral diseases (e.g. Dengue fever) by transferring these Wolbachia to disease-vector mosquitoes. The S. poulsonii strain of Drosophila neotestacea protects its host from parasitic wasps and nematodes using toxins that preferentially attack the parasites instead of the host.
Since the Drosophila species is one of the most used model organisms, it was vastly used in genetics. However, the effect abiotic factors, such as temperature, has on the microbiome on Drosophila species has recently been of great interest. Certain variations in temperature have an impact on the microbiome. It was observed that higher temperatures (31 °C) lead to an increase of Acetobacter populations in the gut microbiome of Drosophila melanogaster as compared to lower temperatures (13 °C). In low temperatures (13 °C), the flies were more cold resistant and also had the highest concentration of Wolbachia.
The microbiome in the gut can also be transplanted among organisms. It was found that Drosophila melanogaster became more cold-tolerant when the gut microbiota from Drosophila melanogaster that were reared at low temperatures. This depicted that the gut microbiome is correlated to physiological processes.
Moreover, the microbiome plays a role in aggression, immunity, egg-laying preferences, locomotion and metabolism. As for aggression, it plays a role to a certain degree during courtship. It was observed that germ-free flies were not as competitive compared to the wild-type males. Microbiome of the Drosophila species is also known to promote aggression by octopamine OA signalling. The microbiome has been shown to impact these fruit flies' social interactions, specifically aggressive behaviour that is seen during courtship and mating.
Predators
Drosophila species are prey for many generalist predators, such as robber flies. In Hawaii, the introduction of yellowjackets from mainland United States has led to the decline of many of the larger species. The larvae are preyed on by other fly larvae, staphylinid beetles, and ants.
Neurochemistry
Fruit flies use several fast-acting neurotransmitters, similar to those found in humans, which allow neurons to communicate and coordinate behavior. Acetylcholine, glutamate, gamma-aminobutyric acid (GABA), dopamine, serotonin, and histamine are all neurotransmitters that can be found in humans, but Drosophila also have another neurotransmitter, octopamine, the analog of norepinephrine. Acetylcholine is the primary excitatory neurotransmitter and GABA is the primary inhibitory neurotransmitter utilized in the drosophila central nervous system. In Drosophila, the effects of many neurotransmitters can vary depending on the receptors and signaling pathways involved, allowing them to act as excitatory or inhibitory signals under different contexts. This versatility enables complex neural processing and behavioral flexibility.
Glutamate can serve as an excitatory neurotransmitter, specifically at the neuromuscular junction in fruit flies. This differs from vertebrates, where acetylcholine is used at these junctions.
In Drosophila, histamine primarily functions as a neurotransmitter in the visual system. It is released by photoreceptor cells to transmit visual information from the eye to the brain, making it essential for vision.
As with many Eukaryotes, this genus is known to express SNAREs, and as with several others the components of the SNARE complex are known to be somewhat substitutable: Although the loss of SNAP-25 - a component of neuronal SNAREs - is lethal, SNAP-24 can fully replace it. For another example, an R-SNARE not normally found in synapses can substitute for synaptobrevin.
Immunity
The Spätzle protein is a ligand of Toll. In addition to melanin's more commonly known roles in the endoskeleton and in neurochemistry, melanization is one step in the immune responses to some pathogens. Dudzic et al. 2019 additionally find a large number of shared serine protease messengers between Spätzle/Toll and melanization and a large amount of crosstalk between these pathways.
Systematics
The genus Drosophila as currently defined is paraphyletic (see below) and contains 1,450 described species, while the total number of species is estimated at thousands. The majority of the species are members of two subgenera: Drosophila (about 1,100 species) and Sophophora (including D. (S.) melanogaster; around 330 species).
The Hawaiian species of Drosophila (estimated to be more than 500, with roughly 380 species described) are sometimes recognized as a separate genus or subgenus, Idiomyia, but this is not widely accepted. About 250 species are part of the genus Scaptomyza, which arose from the Hawaiian Drosophila and later recolonized continental areas.
Evidence from phylogenetic studies suggests these genera arose from within the genus Drosophila:
Liodrosophila Duda, 1922
Mycodrosophila Oldenburg, 1914
Samoaia Malloch, 1934
Scaptomyza Hardy, 1849
Zaprionus Coquillett, 1901
Zygothrica Wiedemann, 1830
Hirtodrosophila Duda, 1923 (position uncertain)
Several of the subgeneric and generic names are based on anagrams of Drosophila, including Dorsilopha, Lordiphosa, Siphlodora, Phloridosa, and Psilodorha.
Genetics
Drosophila species are extensively used as model organisms in genetics (including population genetics), cell biology, biochemistry, and especially developmental biology. Therefore, extensive efforts are made to sequence drosophilid genomes. The genomes of these species have been fully sequenced:
Drosophila (Sophophora) melanogaster
Drosophila (Sophophora) simulans
Drosophila (Sophophora) sechellia
Drosophila (Sophophora) yakuba
Drosophila (Sophophora) erecta
Drosophila (Sophophora) ananassae
Drosophila (Sophophora) pseudoobscura
Drosophila (Sophophora) persimilis
Drosophila (Sophophora) willistoni
Drosophila (Drosophila) mojavensis
Drosophila (Drosophila) virilis
Drosophila (Drosophila) grimshawi
The data have been used for many purposes, including evolutionary genome comparisons. D. simulans and D. sechellia are sister species, and provide viable offspring when crossed, while D. melanogaster and D. simulans produce infertile hybrid offspring. The Drosophila genome is often compared with the genomes of more distantly related species such as the honeybee Apis mellifera or the mosquito Anopheles gambiae.
The Drosophila modEncode project conducted extensive work to annotate Drosophila genomes, profile transcripts, histone modifications, transcription factors, regulatory networks, and other aspects of Drosophila genetics, and make predictions about gene expression among others.
FlyBase serves as a centralized database of curated genomic data on Drosophila.
The has presented ten new genomes and combines those with previously released genomes for D. melanogaster and D. pseudoobscura to analyse the evolutionary history and common genomic structure of the genus. This includes the discovery of transposable elements (TEs) and illumination of their evolutionary history. Bartolomé et al. 2009 find at least of the TEs in D. melanogaster, D. simulans and D. yakuba have been acquired by horizontal transfer. They find an average rate of 0.035 horizontal transfer events per TE family per million years. Bartolomé also finds horizontal transfer of TEs follows other relatedness metrics, with transfer events between D. melanogaster and D. simulans being twice as common as either of them with D. yakuba.
See also
Drosophila hybrid sterility
Laboratory experiments of speciation
List of Drosophila species
Caenorhabditis 'Drosophilae' species supergroup, a group of species generally found on rotten fruits and transported by Drosophila flies
References
External links
FlyBase is a comprehensive database for information on the genetics and molecular biology of Drosophila. It includes data from the Drosophila Genome Projects and data curated from the literature.
is an integrated database of genomic, expression and protein data for Drosophila
University of California, Santa Cruz
breeds hundreds of species and supplies them to researchers
Lawrence Berkeley National Laboratory
is library of Drosophila on the web
– In India microinjection service for the generation of transgenic lines, Screening Platforms, Drosophila strain development
Drosophilidae genera
Taxa named by Carl Fredrik Fallén
Animal models | Drosophila | Biology | 5,354 |
31,712,282 | https://en.wikipedia.org/wiki/OStatus | OStatus is an open standard for decentralized social networking, allowing users on one service to send and receive status updates with users from another. The standard describes how a suite of various standards, including Atom, Activity Streams, WebSub, Salmon, and WebFinger, can be used together, which enables different microblogging server implementations to communicate status updates between their users back-and-forth, in near real-time.
History
OStatus federation was first possible between servers running StatusNet, such as Status.net and Identi.ca, although Identi.ca later switched to pump.io. As of June 2013, a number of other microblogging applications and content management systems had announced that they intended to implement the standard. That same month, it was announced StatusNet would be merged into the GNU social project along with Free Social, a similar application itself forked from StatusNet.
Following the first official release of GNU Social, a number of microblogging sites running StatusNet and Free Social began to transition to it to receive new updates to the software. But frustrations with the technology underpinning GNU Social and its complexity led a number of new server packages that aimed to be compatible with GNU Social using OStatus to shift focus to ActivityPub, including Mastodon, Pleroma and postActiv, a fork of GNU social.
Standards work
In January 2012, a W3C Community Group was opened to maintain and further develop the OStatus standard. However, this was eclipsed by the work of the W3C Federated Social Web Working Group, launched in July 2014. This working group focused on creating a newer standard, called ActivityPub, which expanded on the protocols and design used in pump.io, which has since been standardized as a successor to OStatus.
Projects using OStatus
Current
GNU social (formerly StatusNet)
Former
Friendica
Mastodon
Pleroma
See also
OpenMicroBlogging – older federated microblogging specification, to be superseded by OStatus.
Comparison of software and protocols for distributed social networking
Comparison of microblogging and similar services
References
External links
OStatus Wiki
Microblogging software
Communications protocols
Software that federates via OStatus | OStatus | Technology | 466 |
19,278,728 | https://en.wikipedia.org/wiki/Architectural%20engineering | Architectural engineering or architecture engineering, also known as building engineering, is a discipline that deals with the engineering and construction of buildings, such as environmental, structural, mechanical, electrical, computational, embeddable, and other research domains. It is related to Architecture, Mechatronics Engineering, Computer Engineering, Aerospace Engineering, and Civil Engineering, but distinguished from Interior Design and Architectural Design as an art and science of designing infrastructure through these various engineering disciplines, from which properly align with many related surrounding engineering advancements.
From reduction of greenhouse gas emissions to the construction of resilient buildings, architectural engineers are at the forefront of addressing several major challenges of the 21st century. They apply the latest scientific knowledge and technologies to the design of buildings. Architectural engineering as a relatively new licensed profession emerged in the 20th century as a result of the rapid technological developments. Architectural engineers are at the forefront of two major historical opportunities that today's world is immersed in: (1) that of rapidly advancing computer-technology, and (2) the parallel revolution of environmental sustainability.
Architects and architectural engineers both play crucial roles in building design and construction, but they focus on different aspects. Architectural engineers specialize in the technical and structural aspects, ensuring buildings are safe, efficient, and sustainable. Their education blends architecture with engineering, focusing on structural integrity, mechanical systems, and energy efficiency. They design and analyze building systems, conduct feasibility studies, and collaborate with architects to integrate technical requirements into the overall design. Architects, on the other hand, emphasize the aesthetic, functional, and spatial elements, developing design concepts and detailed plans to meet client needs and comply with regulations. Their education focuses on design theory, history, and artistic aspects, and they oversee the construction process to ensure the design is correctly implemented.
Subdisciplines of architectural engineering
Mechanical, electrical, and plumbing (MEP)
Mechanical engineering and electrical engineering engineers are specialists when engaged in the building design fields. This is known as mechanical, electrical, and plumbing (MEP) throughout the United States, or building services engineering in the United Kingdom, Canada, and Australia. Mechanical engineers often design and oversee the heating, ventilation and air conditioning (HVAC), plumbing, and rainwater systems. Plumbing designers often include design specifications for simple active fire protection systems, but for more complicated projects, fire protection engineers are often separately retained. Electrical engineers are responsible for the building's power distribution, telecommunication, fire alarm, signalization, lightning protection and control systems, as well as lighting systems.
Structural Engineering
Structural engineering involves the analysis and design of the built environment (buildings, bridges, equipment supports, towers and walls). Those concentrating on buildings are sometimes informally referred to as "building engineers". Structural engineers require expertise in strength of materials, structural analysis, and in predicting structural load such as from weight of the building, occupants and contents, and extreme events such as wind, rain, ice, and seismic design of structures which is referred to as earthquake engineering. Architectural engineers sometimes incorporate structural as one aspect of their designs; the structural discipline when practiced as a specialty works closely with architects and other engineering specialists.
Sustainable Engineering
Sustainable engineering involves designing or operating systems to use energy and resources in a way that maintains environmental balance and ensures that future generations can meet their own needs without compromising the natural environment. Architectural engineers are influenced by sustainable engineering principles in their education, training, and practice, integrating sustainable design strategies to create buildings and structures that minimize environmental impact and enhance energy efficiency.
Building Envelope Engineering
Building enclosure and façade engineering involves the design and management of the outer shell of a building, which acts as a barrier between the interior and exterior environments. This includes walls, roofs, windows, doors, and other components that collectively ensure the building is protected from external elements such as air, water, heat, light, and noise.
The building envelope plays a crucial role in maintaining indoor comfort by controlling temperature, humidity, and airflow. It also contributes to the building's energy efficiency by minimizing heat loss in the winter and heat gain in the summer. Engineers in this field work on making sure the envelope is structurally sound, aesthetically pleasing, and performs effectively to meet various functional requirements.
Fire Protection Engineering
Fire protection engineering is a subfield of building engineering focused on the design and application of systems and practices that prevent, control, and mitigate the impact of fires. This discipline aims to protect people, property, and the environment from the destructive effects of fire through a combination of preventive measures, detection systems, and response strategies.
Fire protection engineers use their expertise to analyze potential fire scenarios, model the spread of fire and smoke, and design systems that effectively protect lives and property. They collaborate with architects, builders, and safety officials to integrate fire protection measures into the overall design and operation of buildings and facilities.
Acoustical Engineering
Acoustical or acoustics engineering in building design focuses on controlling sound within and around buildings to create a comfortable and functional auditory environment. This discipline involves the study and application of principles to manage noise levels, improve sound quality, and ensure effective sound insulation.
Acoustical engineers work closely with architects, builders, and other engineers to integrate sound control measures into the overall design of a building. They use advanced modeling and simulation tools to predict how sound will behave in different spaces and employ various materials and techniques to achieve the desired acoustic performance. Their goal is to create environments that are acoustically comfortable, meeting the specific needs of the building's occupants and its intended use.
The architectural engineer (PE) in the United States
In many jurisdictions of the United States, the architectural engineer is a licensed engineering professional. Usually a graduate of an EAC/ABET-accredited architectural engineering university program preparing students to perform whole-building design in competition with architect-engineer teams; or for practice in one of structural, mechanical or electrical fields of building design, but with an appreciation of integrated architectural requirements. Although some states require a BS degree from an EAC/ABET-accredited engineering program, with no exceptions, about two thirds of the states accept BS degrees from ETAC/ABET-accredited architectural engineering technology programs to become licensed engineering professionals. Architectural engineering technology graduates, with applied engineering skills, often gain further learning with an MS degree in engineering and/or NAAB-accredited Masters of Architecture to become licensed as both an engineer and architect. This path requires the individual to pass state licensing exams in both disciplines. States handle this situation differently on experienced gained working under a licensed engineer and/or registered architect prior to taking the examinations. This education model is more in line with the educational system in the United Kingdom where an accredited MEng or MS degree in engineering for further learning is required by the Engineering Council to be registered as a Chartered Engineer. The National Council of Architectural Registration Boards (NCARB) facilitate the licensure and credentialing of architects but requirements for registration often vary between states. In the state of New Jersey, a registered architect is allowed to sit for the PE exam and a professional engineer is allowed to take the design portions of the Architectural Registration Exam (ARE), to become a registered architect.
Formal architectural engineering education, following the engineering model of earlier disciplines, developed in the late 19th century, and became widespread in the United States by the mid-20th century. With the establishment of a specific "architectural engineering" NCEES Professional Engineering registration examination in the 1990s, and first offering in April 2003, architectural engineering became recognized as a distinct engineering discipline in the United States. Up to date NCEES account allows engineers to apply to other states PE license "by comity".
In most license-regulated jurisdictions, architectural engineers are not entitled to practice architecture unless they are also licensed as architects. Practice of structural engineering in high-risk locations, e.g., due to strong earthquakes, or on specific types of higher importance buildings such as hospitals, may require separate licensing as well. Regulations and customary practice vary widely by state or city.
The architect as architectural engineer
In some countries, the practice of architecture includes planning, designing and overseeing the building's construction, and architecture, as a profession providing architectural services, is referred to as "architectural engineering". In Japan, a "first-class architect" plays the dual role of architect and building engineer, although the services of a licensed "structural design first-class architect"(構造設計一級建築士) are required for buildings over a certain scale.
In some languages, such as Korean and Arabic, "architect" is literally translated as "architectural engineer". In some countries, an "architectural engineer" (such as the ingegnere edile in Italy) is entitled to practice architecture and is often referred to as an architect. These individuals are often also structural engineers. In other countries, such as Germany, Austria, Iran, and most of the Arab countries, architecture graduates receive an engineering degree (Dipl.-Ing. – Diplom-Ingenieur).
In Spain, an "architect" has a technical university education and legal powers to carry out building structure and facility projects.
In Brazil, architects and engineers used to share the same accreditation process (Conselho Federal de Engenheiros, Arquitetos e Agrônomos (CONFEA) – Federal Council of Engineering, Architecture and Agronomy). Now the Brazilian architects and urbanists have their own accreditation process (CAU – Architecture and Urbanism Council). Besides traditional architecture design training, Brazilian architecture courses also offer complementary training in engineering disciplines such as structural, electrical, hydraulic and mechanical engineering. After graduation, architects focus in architectural planning, yet they can be responsible to the whole building, when it concerns to small buildings (except in electric wiring, where the architect autonomy is limited to systems up to 30kVA, and it has to be done by an Electrical Engineer), applied to buildings, urban environment, built cultural heritage, landscape planning, interiorscape planning and regional planning.
In Greece licensed architectural engineers are graduates from architecture faculties that belong to the Polytechnic University, obtaining an "Engineering Diploma". They graduate after 5 years of studies and are fully entitled architects once they become members of the Technical Chamber of Greece (TEE – Τεχνικό Επιμελητήριο Ελλάδος). The Technical Chamber of Greece has more than 100,000 members encompassing all the engineering disciplines as well as architecture. A prerequisite for being a member is to be licensed as a qualified engineer or architect and to be a graduate of an engineering and architecture schools of a Greek university, or of an equivalent school from abroad. The Technical Chamber of Greece is the authorized body to provide work licenses to engineers of all disciplines as well as architects, graduated in Greece or abroad. The license is awarded after examinations. The examinations take place three to four times a year. The Engineering Diploma equals a master's degree in ECTS units (300) according to the Bologna Accords.
Education
The architectural, structural, mechanical and electrical engineering branches each have well established educational requirements that are usually fulfilled by completion of a university program.
In Canada, a CEAB-accredited engineer degree is the minimum academic requirement for registration as a P.Eng (professional engineer) anywhere in Canada and the standard against which all other engineering academic qualifications are measured. A graduate of a non-CEAB-accredited program must demonstrate that his or her education is at least equivalent to that of a graduate of a CEAB-accredited program.
In Vietnam, the engineer's degree is called Bằng kỹ sư, the first degree after five years of study. The Ministry of Education of Vietnam has also issued separate regulations for the naming of degrees not in accordance with international regulation.
Architectural engineering as a single integrated field of study
Its multi-disciplinary engineering approach is what differentiates architectural engineering from architecture (the field of the architect): which is an integrated, separate and single, field of study when compared to other engineering disciplines.
Through training in and appreciation of architecture, the field seeks integration of building systems within its overall building design. Architectural engineering includes the design of building systems including heating, ventilation and air conditioning (HVAC), plumbing, fire protection, electrical, lighting, architectural acoustics, and structural systems. In some university programs, students are required to concentrate on one of the systems; in others, they can receive a generalist architectural or building engineering degree.
See also
Architectural drawing
Architectural technologist
Architectural technology
Building engineer
Building officials
Civil engineering
Construction engineering
Contour crafting
DIN 276
History of architectural engineering
International Building Code
Fire protection engineering
Mechanical, electrical, and plumbing
Outline of architecture
Storm hardening
Associations
Architectural Engineering Institute (AEI) of American Society of Civil Engineers (ASCE)
American Institute of Architects (AIA)
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
American Society of Plumbing Engineers (ASPE)
Associated General Contractors (AGC)
Illuminating Engineering Society (IES)
Institute of Electrical and Electronics Engineers (IEEE)
National Fire Protection Association (NFPA)
National Society of Professional Engineers (NPSE)
Society of Fire Protection Engineers (SFPE)
U.S. Green Building Council (USGBC)
References
Building engineering
Engineering occupations
Architecture occupations
Architectural design
Engineering disciplines | Architectural engineering | Engineering | 2,686 |
43,167,851 | https://en.wikipedia.org/wiki/Penicillium%20argentinense | Penicillium argentinense is a fungus species of the genus of Penicillium.
See also
List of Penicillium species
References
argentinense
Fungi described in 2011
Fungus species | Penicillium argentinense | Biology | 39 |
52,019,383 | https://en.wikipedia.org/wiki/NGC%20294 | NGC 294 is an open cluster located in the Small Magellanic Cloud in the constellation Tucana. It was discovered on April 11, 1834, by John Herschel, although it was possibly observed on September 5, 1826, by James Dunlop.
References
External links
0294
18340411
18260905
Tucana
Discoveries by James Dunlop
Small Magellanic Cloud
Open clusters | NGC 294 | Astronomy | 78 |
69,086,923 | https://en.wikipedia.org/wiki/Taurob%20Inspector | Taurob Inspector is an ATEX certified mobile robot, developed and manufactured by the Austrian company Taurob GmbH. The Inspector was developed from the Taurob Tracker as part of the OGRIP (Offshore Ground Robotics Industrial Pilot) project.
History
Project inception
With Taurob's victory in the ARGOS challenge, the commercially available Taurob Tracker in addition to the ARGOS robot were evaluated for operational use within an Oil & Gas environment. From this evaluation the foundation specification for the Taurob Inspector was created with the first prototypes being developed in early 2018.
First deployments
Taurob inspects are currently being operated on a 12 month deployment on Total Energies' Shetland Gas Plant.
World first offshore deployment
The first ever offshore deployment of an ATEX certified robot in 2020 on Total Energies' K5 gas field 110km off the coast of the Netherlands.
Production centre
In 2021 Taurob opened a subsidiary for the serial manufacture of robots - "Taurob Services S.A.S" with partner Dietsmann Smart Labs, a 100% subsidiary of Dietsmann NV. The subsidiary is based in Salies-du-Salat, France and is housed within Dietsmann's 24,000m² engineering and construction site. The inspector is the first robot to be produced by this venture, with the first robots leaving the production line in Q3 2021.
Technical specification
References
External links
Official Website (English)
Science and technology in Austria
Robots | Taurob Inspector | Physics,Technology | 298 |
46,519,707 | https://en.wikipedia.org/wiki/Low%20power%20flip-flop | Low power flip-flops are flip-flops that are designed for low-power electronics, such as smartphones and notebooks. A flip-flop, or latch, is a circuit that has two stable states and can be used to store state information.
Motivation
In most VLSI devices, a large portion of power dissipation is due to the clock network and clocked sequential elements, which can account for anywhere between 25% - 40% of the total power in a design. Sequential elements, latches, and flip-flops dissipate power when there is switching in their internal capacitance. This may happen with every clock transition/pulse into the sequential element. Sometimes the sequential elements need to change their state, but sometimes they retain their state and their output remains the same, before and after the clock pulse. This leads to unnecessary dissipation of power due to clock transition. If flip-flops are designed in such a way that they are able to gate the clock with respect to their own internal data path, power dissipation can be brought down.
Techniques
Conditional clocking
Conditional pre-charging
This technique is used for controlling the internal node in the pre charging path in a sequential element. In the above circuit, the D input is connected to the first NMOS in the PDN network (CMOS). When this input is high, the output should also be high. The clk input to the PMOS will charge the output node to high when clk is low. If the D input is already high, there is no need to charge the output to high again. Thus, if one can control this behaviour there can be a power reduction in the flip-flop. To control the internal node in the precharge path, a control switch is used as shown in Fig 1. Only a transition that is going to change the state of the output is allowed. As one of the input to flops is the clock, considering the clock (Clock signal) is the element that makes the most transition in a system, a technique such as conditional precharging can significantly help reduce power.
Conditional capture
This technique looks to prevent any necessary internal node transition by looking at the input and output and checking to see if there is a need to switch states. In this circuit, there is a control signal that is applied to control the switching of the internal nodes. We can see the clock is supplied to two NMOS in series. The discharge path will not be complete until the control signal allows the last NMOS to be on. This control signal could be generated by a simple circuit, with its inputs being the present output, input and the state of the clock (high or low). If the output of the flip-flop is low, and a high clock pulse is applied with the input being a low pulse, then there is no need for a state transition. The extra computation to sample the inputs cause an increase in setup time of the flip-flop; this is a disadvantage of this technique.
Data transition look-ahead
In Fig3, the circuit shows how the data transition technique can be beneficial for power saving. The XNOR logical function is performed on the input of the D flip-flop and the output Q. When Q and D are equal, output of the logical XNOR will be zero, generating no internal clock. The circuit can be broken down into 3 parts: data-transition look ahead, pulse generator, and clock generator. The pulse generator output is fed into the clock generator which is used to clock the D flip-flop. Based on the input and output signals, if there is a need to change the state of the D flip-flop, then the clock is allowed to switch to cause a transition; else, the clock is not allowed to transition. When the clock does not make a transition, some time has been already spent in computing the logic, and data from the D input may make it through the first stage of the flip-flop, consuming some power. This power consumption is still less than what an ordinary flipflop would have consumed with a clock transition and no change in output.
Clock on demand
Fig4 shows the clock on demand technique. The clock generator and pulse generator are combined in this implementation. The advantage of this is that there is reduction in area, improving energy efficiency. If the XNOR output is zero, then the pulse generator will not generate any internal signal from the external clock. If the output Q and input D do not match then the pulse generator will generate an internal clock to trigger a state transition.
References
Digital electronics | Low power flip-flop | Engineering | 937 |
52,744,529 | https://en.wikipedia.org/wiki/Grossman-Stiglitz%20Paradox | The Grossman-Stiglitz Paradox is a paradox introduced by Sanford J. Grossman and Joseph Stiglitz in a joint publication in American Economic Review in 1980 that argues perfectly informationally efficient markets are an impossibility since, if prices perfectly reflected available information, there is no profit to gathering information, in which case there would be little reason to trade and markets would eventually collapse.
Rational efficient markets formulation
The rational efficient markets formulation recognizes that investors will not rationally incur the expenses of gathering information unless they expect to be rewarded by higher gross returns compared with the free alternative of accepting the market price. Furthermore, modern theorists recognize that when intrinsic value is difficult to determine, as is the case of common stock, and when trading costs exist, even further room exists for price to diverge from value.
A corollary is that investors who purchase index funds or ETFs are benefitting at the expense of investors who pay for the services of financial advisors, either directly or indirectly through the purchase of actively managed funds.
References
External links
Information economics
Asymmetric information
Management cybernetics
1980 in economic history | Grossman-Stiglitz Paradox | Physics | 224 |
78,116,473 | https://en.wikipedia.org/wiki/Kwagalana%20Group | Kwagalana Group is a members only group of richest businessmen and women in Uganda. Together, the group led by Godfrey Kirumira was estimated to be worth over UGX1,000 billion/USD272 million in 2009. The group was started in 2002 by a group of rich men, but the membership has since grown to include several businessmen like Sudhir Ruparelia of Ruparelia Group Joseph Magandaazi Yiga Hamis Kiggundu among several other rich Ugandans.
Philanthropy
The Kwagalana Group is known for its work of philanthropy by its members. The members of the group have been known to contribute to the communities and the country's development through business and charity. Sudhir Ruparelia in particular has a foundation has benefited several children and women.
During the COVID-19 Pandemic, the Kwagalana Group donated a pickup truck to the health ministry to help transport materials to different health facilities. This followed a call for donations from Yoweri Museveni Members also made individual contributions to the same cause.
Business
Members of Kwagalana Group own several businesses in Uganda, including hotels, Fuel Companies, Schools, Real Estate Companies mong others. These include; Kirumira's Bargary Company Limited deals in fuel, and Sudhir's hotels, apartments, schools etc. Other members of Kwagalana Group include Joseph Magandaazi Yiga the proprietor Steel and Tube Industries Dr Sarah Nkonge, who owns several arcades in Kampala and Jinja. She was also the first woman to be appointed Kampala City Mayor. Mr Ben Kavuya, the Proprietor Legacy Group and Hamis Kiggundu the proprietor Ham Enterprises, among other members.
References
Business organisations based in Uganda
Philanthropy | Kwagalana Group | Biology | 358 |
1,140,453 | https://en.wikipedia.org/wiki/Tremella%20fuciformis | Tremella fuciformis is a species of fungus; it produces white, frond-like, gelatinous basidiocarps (fruiting bodies). It is widespread, especially in the tropics, where it can be found on the dead branches of broadleaf trees. This fungus is commercially cultivated and is one of the most popular fungi in the cuisine and medicine of China. T. fuciformis is commonly known as snow fungus, snow ear, silver ear fungus, white jelly mushroom, and white cloud ears.
T. fuciformis is a parasitic yeast, and grows as a slimy, mucus-like film until it encounters its preferred hosts, various species of Annulohypoxylon (or possibly Hypoxylon) fungi, whereupon it then invades, triggering the aggressive mycelial growth required to form the fruiting bodies.
Description
Fruit bodies are gelatinous, watery white, up to across (larger in cultivated specimens), and composed of thin but erect, seaweed-like, branching fronds, often crisped at the edges. Microscopically, the hyphae are clamped and occur in a dense gelatinous matrix. Haustorial cells arise on the hyphae, producing filaments that attach to and penetrate the hyphae of the host. The basidia are tremelloid (ellipsoid, with oblique to vertical septa), 10–13 μm × 6.5–10 μm, sometimes stalked. The spores are ellipsoid, smooth, 5–8 μm × 4–6 μm, and germinate by hyphal tube or by yeast cells.
Similar species
Ductifera pululahuana is more opaque, as is Sebacina sparassoidea, which grows on the ground.
Taxonomy
Tremella fuciformis was first described in 1856 by English mycologist Miles Joseph Berkeley, based on collections made in Brazil by botanist and explorer Richard Spruce. In 1939, Japanese mycologist Yosio Kobayasi described Nakaiomyces nipponicus, a similar-looking fungus that differed by having scattered, dark spines on its surface. Later research, however, showed that the fruit bodies were those of Tremella fuciformis parasitized by an ascomycete, Ceratocystis epigloeum, that formed the dark spines. Nakaiomyces nipponicus is therefore a synonym of T. fuciformis.
In Mandarin Chinese, it is called 银耳 (pinyin: yín ěr; literally "silver ear"), 雪耳 (pinyin: xuě ěr; literally "snow ear"); or 白木耳 (pinyin: bái mù ěr, literally "white wood ear"), and in Japanese it is called shiro kikurage (シロキクラゲ, lit. "white tree jellyfish"). In Vietnam, it is called nấm tuyết or ngân nhĩ.
According to Paul Stamets, common names for T. fuciformis include: white jelly mushroom, yin er, white jelly fungus, white jelly leaf ("shirokikurage"), silver ear mushroom, snow mushroom, and chrysanthemum mushroom.
Distribution and habitat
Tremella fuciformis is known to be a parasite of Hypoxylon species. Many of these species were reassigned to a new genus, Annulohypoxylon, in 2005 including its preferred host, Annulohypoxylon archeri, the species routinely used in commercial cultivation. Following its host, fruit bodies are typically found on dead, attached or recently fallen branches of broadleaf trees.
The species is mainly tropical and subtropical, but extends into temperate areas in Asia and North America. It is known throughout South and Central America, the Caribbean, parts of North America, sub-Saharan Africa, southern and eastern Asia, Australia, New Zealand (although this may be an NZ indigenous species), and the Pacific Islands.
Uses
Tremella fuciformis has been cultivated in China since at least the nineteenth century. Initially, suitable wooden poles were prepared and then treated in various ways in the hope that they would be colonized by the fungus. This haphazard method of cultivation was improved when poles were inoculated with spores or mycelium. Modern production only began, however, with the realization that both the Tremella and its host species needed to be inoculated into the substrate to ensure success. The "dual culture" method, now used commercially, employs a sawdust mix inoculated with both fungal species and kept under optimal conditions. The most popular species to pair with T. fuciformis is its preferred host, Annulohypoxylon archeri. Estimated production in China in 1997 was 130,000 tonnes. T. fuciformis is also cultivated in other East Asian countries, with some limited cultivation elsewhere.
In Chinese cuisine, T. fuciformis is traditionally used in sweet dishes. While tasteless, it is valued for its gelatinous texture as well as its supposed medicinal benefits. Most commonly, it is used to make a dessert soup called luk mei () in Cantonese, often in combination with jujubes, dried longans, and other ingredients. It is also used as a component of a drink and as an ice cream. Since cultivation has made it less expensive, it is now additionally used in some savoury dishes.
In Vietnamese cuisine, it is often used in Chè (Vietnamese pronunciation: [cɛ̂]), a Vietnamese term that refers to any traditional Vietnamese sweet beverage, dessert soup or pudding.
Cosmetics
T. fuciformis extract is used in women's beauty products from China, Korea, and Japan. The fungus reportedly increases moisture retention in the skin and prevents senile degradation of micro-blood vessels in the skin, reducing wrinkles and smoothing fine lines. Other anti-aging effects come from increasing the presence of superoxide dismutase in the brain and liver; it is an enzyme that acts as a potent antioxidant throughout the body, particularly in the skin. It can also be used for anti-inflammatory purposes. The medical benefits that come from this organism are vast, ranging from boosting immune health to lowering heart disease. T. fuciformis is also known in Chinese medicine for nourishing the lungs.
See also
References
External links
fuciformis
Edible fungi
Fungi in cultivation
Fungi of Africa
Fungi of Asia
Fungi of Australia
Fungi of Central America
Fungi of New Zealand
Fungi of North America
Fungi of the Caribbean
Fungi of South America
Fungi described in 1856
Taxa named by Miles Joseph Berkeley
Fungus species | Tremella fuciformis | Biology | 1,375 |
27,287,411 | https://en.wikipedia.org/wiki/CIT%20Program%20Tumor%20Identity%20Cards | The "Cartes d'Identité des Tumeurs (CIT)" program, launched and funded by the French charity "Ligue Nationale contre le Cancer," aims to improve or develop better targeted therapeutic approaches by refining molecular knowledge of multiple types of tumors. The CIT program mainly relies on the large-scale and systematic profiling of large cohorts of tumors at various molecular levels including at least the genome, the epigenome, and the transcriptome.
See also
Precision medicine
Oncology
Cancer Research
Bioinformatics
Computational genomics
Oncogenomics
Genomics
Transcriptome
Gene expression profiling
References
External links
Official web site
List of main scientific publications
Evidence-based medicine
Medical diagnosis
Bioinformatics
Biostatistics
Cancer research | CIT Program Tumor Identity Cards | Engineering,Biology | 153 |
27,109,167 | https://en.wikipedia.org/wiki/Fluotracen | Fluotracen (SKF-28,175) is a tricyclic drug which has both antidepressant and antipsychotic activity. This profile of effects is similar to that of related agents like amoxapine, loxapine, and trimipramine which may also be used in the treatment of both depression and psychosis. It was believed that such duality would be advantageous in the treatment of schizophrenia, as depression is often comorbid with the disorder and usual antipsychotics often worsen such symptoms. In any case, however, fluotracen was never marketed.
See also
Litracen
Melitracen
References
Dimethylamino compounds
Anthracenes
Antipsychotics
Tricyclic antidepressants
Trifluoromethyl compounds
Abandoned drugs | Fluotracen | Chemistry | 169 |
354,977 | https://en.wikipedia.org/wiki/Urban%20planning%20in%20communist%20countries | Urban planning in the Soviet Bloc countries during the Cold War era was dictated by ideological, political, social as well as economic motives. Unlike the urban development in the Western countries, Soviet-style planning often called for the complete redesigning of cities.
This thinking was reflected in the urban design of all communist countries. Most socialist systems exercised a form of centrally controlled development and simplified methods of construction already outlined in the Soviet guidelines at the end of the Stalinist period. The communist planning resulted in the virtually identical city blocks being erected across many nations, even if there were differences in the specifics between each country.
Soviet-style cities are often traced to Modernist ideas in architecture such as those of Le Corbusier and his plans for Paris. The housing developments generally feature tower blocks in park-like settings, standardized and mass-produced using structural insulated panels within a short period of time.
Beginnings of urban planning in communist countries
Many eastern European countries had suffered physical damage during World War II and their economies were in a very poor state. There was a need to reconstruct cities which had been severely damaged due to the war. For example, Warsaw, Poland, had been practically razed to the ground under the planned destruction of Warsaw by German forces after the 1944 Warsaw Uprising. The centre of Dresden, Germany, had been totally destroyed by the 1945 Allied bombardment. Stalingrad had been largely destroyed and only a small number of structures were left standing.
The financial resources of eastern European countries, after nationalization of industry and land, were under total government control. All development and investment had to be financed by the state. In line with their commitment to communism, the first priority was building industry.
Therefore, for the first ten to fifteen years, most resources were directed towards the development of industry and the reconstruction of destroyed cities. In most cases, this reconstruction was executed without any urban planning for several reasons. Firstly, reconstruction had to start immediately as there was not enough time to develop a detailed plan. Secondly, the man-power and expertise for developing urban plans in great numbers were not available.
Oftentimes, destroyed cites were not rebuilt as they were before. Rather, entirely new cities were constructed along the principles of Soviet Socialism. However, the historically significant structures in some large cities were rebuilt. Experts worked to make the restoration resemble the original as much as possible. For example, the old city centre in Warsaw, the Zwinger in Dresden, and many historic buildings in Budapest were restored to their pre-war beauty.
A notable exception is the building of the National Theatre of Bucharest, Romania, which was damaged by bombing in August 1944. Though part of the building was still standing, after taking complete power in 1947, the communist authorities decided to tear down the remains of the building.
In the late 1940s, the USSR developed a new type of high-rise. The first such buildings were built in Moscow: Moscow State University, Kotelnicheskaya Embankment Building, Kudrinskaya Square Building, Hilton Moscow Leningradskaya Hotel, Hotel Ukraina, Ministry of Foreign Affairs, Ministry of Heavy Industry. These were duplicated in some other countries, the main examples being the Palace of Culture and Science in Warsaw and the House of the Free Press in Bucharest. The Stalin Allee (subsequently named Karl-Marx-Allee) in East Berlin was also flanked by buildings having the same Stalinist style, though their concept was different from the Moscow high-rises. These buildings are mainly examples of a new architectural style, but did not involve urban planning to a significant extent, and there is no visible conceptual link between these buildings and their neighborhood.
Construction of these buildings required the demolition of the structures which were located on their sites. The most notorious was the demolition of the Cathedral of Christ the Saviour, erected in Moscow as a memorial of Napoleon's defeat. The site was required for the Palace of the Soviets, which was never built. The demolition of historic buildings, especially churches, to make way for the new communist structures was a general trait of communist urbanism. A more recent example was the Demolition of historical parts of Bucharest by Nicolae Ceauşescu who aimed to rebuild the capital in a socialist realist style.
In other cases, the Soviets preserved historic structures and attempted to erase their non-Soviet significance; instead, they focused on aesthetics and perceived beauty. For example, the Vilnius Cathedral was repurposed as an art museum after the Soviet Union retook Lithuania in 1944. Additionally, the names of streets in Vilnius were changed to more closely reflect Soviet values. Over time, the city began to expand, and in the 1978 Master Plan for Vilnius, new districts were proposed, most of which were residential. New private housing was prohibited from the city center and the old town.
Industrialization brought more people from rural areas to the cities. As few new housing units were built immediately after the war, an already severe housing shortages became worse. Eventually, chronic housing shortages and overcrowding required an extensive program of new construction. As a result, most communist countries adopted the solution used in the USSR which included strict limits on the living space to which each person was entitled. Generally, each person was entitled to about 9-10 square meters (100 square feet). Often, more than one person had to share the same room. Two or more generations of the same family would often share an apartment originally built for only one nuclear family. There was no space allocated to separate living and dining areas. After the mid-1950s, new housing policies aimed at the mass construction of larger individual apartments.
First attempts of socialist city planning in Eastern Europe
In the process of socialist industrialization, industrial facilities were built not only near existing cities but also in areas where only small rural communities had existed. In such cases, new urban communities emerged in the vicinity of the industrial plants to accommodate the workers. This is the case of Nowa Huta (1949) in Poland, Dunaújváros (1950) in Hungary, and Oneşti (1952) in Romania.
After World War II, dam construction accelerated due to an abundance of new technology. The relocation of people caused by storage reservoirs on large rivers created the need for new communities. Many river-based traditional villages were demolished and their inhabitants relocated. For instance, in Romania, the construction of the Izvorul Muntelui dam on the Bistriţa river required the relocation of several villages with a population of several thousand people.
These trends of the early post-war years were just a sign of what was to follow in the next decades when the constraints of the reconstruction had been overcome and development was undertaken on a much greater scale. However, the first projects highlighted the need for urban planning in the new localities. This also included the design of the entire infrastructure system such as roads, water supply and power supply and also social impact studies, as in many cases the life-style of the population was severely affected. For example, often farmers whose land had been claimed for development would not get replacement farmland or compensation.
Urban development in the 1960s and 1970s
In the big cities few new housing units were constructed and the existing units were overcrowded. Around 1960, the USSR changed its policy and began an extensive program of construction of new apartment buildings, with the introduction of Khrushchevka and the subsequent introduction of Brezhnevka. This trend was immediately followed by all communist countries in Eastern Europe. The development of new neighborhoods in order to extend the housing capacity of cities required an extensive urban planning effort. In most cities, new development took place on the outskirts of the existing cities, incorporating suburbs or undeveloped land into the city. Also, in cities in which slums existed, the slums were redeveloped with modern housing units.
While the actual design and construction of the apartment buildings is not part of the urban planning exercise, the height and type of the buildings, the density of the buildings and other general characteristics were fixed by the planning exercise. Besides, the entire development of the infrastructure had to be planned. This included the transportation system and the roads, water supply, sewerage, power supply, shopping centers, schools and other infrastructure. Flood control was also a concern for cities located in flood prone areas. The planning also covered the industrial zones where new industries were to be located.
In some parts, urban problems were raised also due to other infrastructure, mainly to the development of waterways. The construction of reservoirs on big rivers in the proximity of cities created new waterfronts which had to be developed. This happened mainly in the Soviet Union, but also in other countries. Also some urban planning was required in the downtown districts where new official buildings were constructed. An example is the development of the area of the congress hall attached to the previous royal palace in the center of Bucharest.
Planning of rural localities
The standardization of living (i.e. hot and cold running water, electricity, access to medicine and education, etc.) between the workers in the urban-cityscape and those in the rural-farming lands was an important piece of foundational Marxism–Leninism in the Soviet Union. But by the early 1970s it became clear that the gradual evolution towards equal standards of living between urban and rural workers, as prescribed by Marxism–Leninism, was lagging. Even more disparaging, significant developments in the quality of life for the villages of the European west greatly surpassed those in the communist east (the majority of which only had electricity). Consequently, the USSR found it necessary to enact policy to improve the lives of villagers and advance its own villages to be more comparable to those in the west.
In the Soviet Union, this policy came about through the systematic construction of urban types of residences, mainly multi-story modern apartment blocks, built on the idea that these buildings could provide a degree of comfort that which the older peasant houses could not. As part of this plan, smaller villages (typically those with populations under 1,000) were deemed irrational or inefficient and a variety of remedies could befall them. The mildest consequence was the village could be slated for reduction of services, given a timely notice of demolition, or the workers were asked voluntarily to leave.
Romania
In time, large-scale demolitions and enormous reconstruction projects of villages, towns, and cities, in whole or in part, began to take shape. One of the largest and most ambitious of these developments began in 1974 with the goal of turning Romania into a "multilaterally developed socialist society". Urban planning, in Romania, began early on as displaced rural Romanians started flocking to the cities. With a "blank canvas" of land, the communist regime hoped to create hundreds of urban industrial centers via investment in schools, medical clinics, housing, and industry.
Although the systematization plan extended, in theory, to the entire country, initial work centered in Moldavia. It also affected such locales as Ceauşescu's own native village of Scorniceşti in Olt County: there, the Ceauşescu family home was the only older building left standing. The initial phase of systematization largely petered out by 1980, at which point only about 10 percent of new housing was being built in historically rural areas.
Given the lack of budget, in many regions systematization did not constitute an effective plan, good or bad, for development. Instead, it constituted a barrier against organic regional growth. New buildings had to be at least two stories high, so peasants could not build small houses. Yards were restricted to 250 square meters and private agricultural plots were banned from within the villages. Despite the obvious negative impact of such a scheme on subsistence agriculture, after 1981 villages were mandated to be agriculturally self-sufficient.
In the mid-1980s the concept of systematization found new life, applied primarily to the area of the nation's capital, Bucharest. Nearby villages were demolished, often in service of large-scale projects such as a canal from Bucharest to the Danube – projects which were later abandoned by Romania's post-communist government. Most dramatically, eight square kilometers in the historic center of Bucharest were leveled. The demolition campaign erased many monuments including 3 monasteries, 20 churches, 3 synagogues, 3 hospitals, 2 theaters and a noted Art Deco sports stadium. This also involved evicting 40,000 people with only a single day's notice and relocating them to new homes, in order to make way for the grandiose Centrul Civic and the immense Palace of the People, a building second in size only to the Pentagon.
Urban planning, especially the destruction of historic churches and monasteries, was protested by several nations, especially Hungary and West Germany, each concerned for their national minorities in Transylvania. Despite these protests, Ceauşescu remained in the relatively good graces of the United States and other Western powers almost to the last, largely because his relatively independent political line rendered him a useful counter to the Soviet Union in Cold War politics.
North Korea
Pyongyang, the capital of North Korea, has a downtown consisting of hundreds of high-rise apartments. North Korean citizens are provided housing by the government, and the quality of said housing is dependent on social status and household size. The city also has several extraordinarily expansive public spaces that are usually built around colossal monuments depicting Juche ideologies and/or monuments relating to Kim Jong-il and Kim Il Sung.
Car ownership rates in Pyongyang are low, and thus public transportation is vital to the city. A two-line subway system serves the city, with a network of elaborate stations, many with high ceilings and murals on their walls. Additionally, an expansive tram network covers the city. There are no suburbs in Pyongyang as the government's city planning policies substitute lower density suburban expansion for high rise residential development in central areas.
People's Republic of China
The development of urban planning in the People's Republic of China (PRC) demonstrates a unique approach with Chinese characteristics. It started after communist takeover in the early 1950s. Through implementing new national urban policies, communist planners first introduced urban planning by applying centralised economic planning and industrialisation, especially in heavy industry.
Phase 1 (1949–1960)
In September 1952, there were two significant policies promulgated at an urban development conference: "construction of key cities in co-ordination with the national economic development programme" and "establishment of urban planning structure to strengthen city development". These policies influenced China's urban planning significantly and at the same time were clearly defined by the main direction of the state – centralised economic and industrial development. During the First Five-year Plan (1953–58), the nation determined to develop 156 national key projects and 8 key industrial based cities. In this period, vast physical development projects such as industrial bases, community facilities and housing for workers were established to achieve national needs and goals. All of these projects were carried out with the aid of the experts from the Soviet Union, particularly in terms of urban economic development and physical urban design. Urban planning at that time was mainly based on Soviet planning principles and the model of the post-war Soviet planning practice. Soviet-style communist planning concentrated on "formalistic street patterns and grand design for public buildings and monuments, huge public squares, and the predominance of master plans". The role of communist planners during this period was to focus on location selection of factories and industrial plants, arrangement of service facilities, design of the layout of industrial towns, functional division of urban land use zones and development of residential districts. Historic preservation was not a priority during this period of development. For example, Mao Zedong allowed Beijing's city walls to be demolished despite their historical significance in order to make room for other uses. The bricks from the walls were used in new development projects ranging from homes to a subway system. By the end of 1959, there were 180 cities, 1400 towns and more than 2,000 suburban residential settlements that had been project plans prepared under communist planning.
Phase 2 (1961–1976)
From 1960 to 1976, due to the political climate changing, the development of urban planning in communist China had suffered severe catastrophes: planning institutions had to cease, planners were assigned to support development in rural areas and planning documents were destroyed or discarded. During the Great Leap Forward in the early 1960s, the utopian socialist planning development which particularly overemphasized large-scale urban development was seen as superior to Western-style planning. However, due to the severe limitations of fiscal and labor resources, the first priority of urban planning was given to utopian socialist principles and then the second place to people's livelihood. Thus, giving little attention to the establishment of residential amenities and facilities, there were significant social and physical imbalances resulting in urban development. For instance, in the historic hutong neighborhoods in Beijing, courtyards were routinely replaced with new residential structures in order to accommodate more residents. By the end of this phase, about 30% of these courtyards had residential structures placed on them. Additionally, some anti-urban movements, a typical example being the People's Commune Movement, took place in communist China during this period. The purpose of setting up a commune, seen as a sub-community within cities, was to spread industrial values from urban to rural areas so that eventually the urban-rural gap would be eliminated.
Phase 3 (1977–1984)
In December 1978, a new era of economic and political reform had begun and accelerated. The major concern of urban planning in communist China shifted to the recognition of the function of cities. Consequently, a nationwide effective force to restore urban master plans was started. By the end of 1984, 241 cities and 1,071 counties throughout the nation as a whole completed their master plans. Although these master plans might not technically fulfill the needs of urban development, they at least acted as guidelines to lead to planned and organised urban construction. In addition, some concepts of mega-metropolitan areas were established during this period.
Phase 4 (1985–present)
Contemporary urban planning in China is undergoing rapid, unprecedented urbanization and industrialization. In fact, China's urbanization rate was almost 50% by the year 2010, a stark contrast from previous decades. Based upon the current Chinese Urban and Rural Planning Act, two tiers – master plan and detailed plan – make up the Chinese urban planning system. Reviewing the history of urban planning in China, the contemporary planning norm is neither simply following Soviet-style planning nor prohibiting advanced Western viewpoints of urban development. Urban renewal and redevelopment are common themes in contemporary Chinese planning. Large swathes of major cities are sometimes torn down at once to allow for new uses. In some cases, residents simply refuse to move out and developers have to adjust their plans accordingly. These residents have been dubbed "nail houses" or "dingzi hu", and there have been many famous cases of these holdouts in Chinese media.
Socialist Federal Republic of Yugoslavia
Post-WWII SFR Yugoslavia followed in line with the earlier urbanist experiments of the Soviet Union, and often delved in urban planning projects.
The best known example would be the Novi Zagreb (eng. "New Zagreb") urban development scheme of the Zagreb city – the capital of the Socialist republic of Croatia.
The district is mostly residential, consisting of blocks of flats and tower blocks that were built during the Socialist era (1945–1990). Although it is not as prestigious as downtown Zagreb, it has been praised for its good road network, public transportation connections and abundance of parks.
The project was started by the mayor of Zagreb, Većeslav Holjevac, as there was a large expanse of empty and undeveloped land south of the Sava river. The land was seized from the Captol church administration following the victory of the communist partisans in World War II. The mayor, seeing the opportunity to set in motion the building of a completely new and modern city under the socialist administration, promptly organized a team of urbanist designers and city planners.
The first complete solution for habitation with public and commercial contents was made for the neighborhood Trnsko by urbanists Zdenko Kolacio, Mirko Maretić and Josip Uhlik with horticulturist Mira Wenzler-Halambek in 1959–1960. It was followed by plans for neighborhood Zapruđe in 1962–1963, also made by Josip Uhlik.
The project was lauded as a great success, the district being known for its large amounts of foliage and recreational areas, including parks, museums and sports fields. A lot of care also went into building a modernized and efficient system of transportation and mass transit, such as tram and bus lines which were built by 1979. Lauding a typical Eastern bloc architectural style, it was designed to house a large capacity of residents, as the construction of the area was in part driven by the need for workforce to fuel the Zagreb industrialization projects recently put in motion. It also has examples of brutalist architecture, rare for the late period the area was constructed in.
See also
Eastern Bloc economies
Sotsgorod: Cities for Utopia
Soviet urban planning ideologies of the 1920s
Urban planning
Large panel system building
Eastern bloc housing:
Panelák (Czechoslovakia)
Panelház (Hungary)
Plattenbau (East Germany)
Ugsarmal bair (Mongolian People's Republic)
Systematization (Romania)
Khrushchevka (Soviet Union)
References
Anania, Lidia; Luminea, Cecilia; Melinte, Livia; Prosan, Ana-Nina; Stoica, Lucia; and Ionescu-Ghinea, Neculai, Bisericile osândite de Ceauşescu. București 1977–1989 (1995). Editura Anastasia, Bucharest, . In Romanian. Title means "Churches doomed by Ceauşescu". This is very much focused on churches, but along the way provides many details about systematization, especially the demolition to make way for Centrul Civic.
Bucica, Cristina. Legitimating Power in Capital Cities: Bucharest – Continuity Through Radical Change? (PDF), 2000.
Chen, Xiaoyan: Monitoring and Evaluation in China's Urban Planning System: A Case Study of Xuzhou, (PDF), 2009.
Ilchenko M. Utopian spaces: Symbolic transformation of the "Socialist Cities" under post-Soviet conditions //Re-Imagining the city: Municipality and Urbanity Today from a Sociological Perspective", Ed. by M. Smagacz-Poziemska, K. Frysztacki, A. Bukowski. Jagiellonian University Press, 2017. P. 32-52
Ilchenko M. “Socialist cities” under post-Soviet conditions: symbolic changes and new ways of representation // EUROPA REGIONAL, 25. 2017 (2018), 2, pp. 30–44
Kirkby, R J. R. Urbanization in China: Town and Country in a Developing Economy, 1949-2000 A.d. New York: Columbia University Press, 1985. Print.
Tang, Wing-Shing; Chinese Urban Planning at Fifty: An Assessment of the Planning Theory Literature Journal of Planning Literature 2000 14: 347-66
Xie, Yichun and Costa F.J.: in: Cities, Volume 10, Issue 2, May 1993, Pages 103-114
Communist states
Eastern Bloc | Urban planning in communist countries | Engineering | 4,742 |
3,011,538 | https://en.wikipedia.org/wiki/Entropy%20of%20vaporization | In thermodynamics, the entropy of vaporization is the increase in entropy upon vaporization of a liquid. This is always positive, since the degree of disorder increases in the transition from a liquid in a relatively small volume to a vapor or gas occupying a much larger space. At standard pressure , the value is denoted as and normally expressed in joules per mole-kelvin, J/(mol·K).
For a phase transition such as vaporization or fusion (melting), both phases may coexist in equilibrium at constant temperature and pressure, in which case the difference in Gibbs free energy is equal to zero:
where is the heat or enthalpy of vaporization. Since this is a thermodynamic equation, the symbol refers to the absolute thermodynamic temperature, measured in kelvins (K). The entropy of vaporization is then equal to the heat of vaporization divided by the boiling point:
According to Trouton's rule, the entropy of vaporization (at standard pressure) of most liquids has similar values. The typical value is variously given as 85 J/(mol·K), 88 J/(mol·K) and 90 J/(mol·K). Hydrogen-bonded liquids have somewhat higher values of
See also
Entropy of fusion
References
Thermodynamic entropy
Thermodynamic properties | Entropy of vaporization | Physics,Chemistry,Mathematics | 283 |
12,750,368 | https://en.wikipedia.org/wiki/Lymph%20heart | A lymph heart is an organ which pumps lymph in lungfishes, amphibians, reptiles, and flightless birds back into the circulatory system. In some amphibian species, lymph hearts are in pairs, and may number as many as 200 in one animal the size of a worm, while newts and salamanders have as many as 16 to 23 pairs of lymph hearts.
Lymph hearts are thought to have evolved in Rhipidistia. Mammals have lost the lymph heart as a centralized organ, instead having the lymph vessel themselves contract to pump lymph.
and other amphibians
The lymphatic system of a frog consists of lymph, lymph vessels, lymph heart, lymph spaces and spleen.
Lymphatics and lymph
As lymph is a filtrate of blood, it closely resembles the plasma in its water content. Lymph also contains a small amount of metabolic waste and a much smaller amount of protein than that of blood. Lymph vessels carry the lymph and, in the frog, open into the four lymph hearts. These lymph hearts are located on the dorsal side of frog's body. The front pair is situated below the shoulder blades. The posterior pair is on either side of a long, rod-like bone called a urostyle, formed by the fusion of the last few vertebrae. The anterior pair opens into the subclavian vein and the posterior pair into the femoral vein. The pair near the third vertebra pumps lymph into the jugular vein. The other pair at the end of the vertebral column pump lymph into the iliac vein in the legs.
The position of mammalian jugular lymph sacs coincide with that of amphibian anterior lymph hearts.
Mechanism of the lymph hearts
The lymph hearts rhythmically and slowly pump to drive the lymph into the veins. It is possible to see the lymph hearts beat by looking on the dorsal surface on either side of the urostyle. In the toad, the normal lymph heart rate is about 50 beats per minute. Thus the lymph emerging out of blood ultimately merges into the blood. It returns the proteins back to blood.
Amphibian lymph hearts are made up from three tissue layers analogous to the three layers of blood vessels. There are the tunica interna intima made up of endothelial cells, tunica media made up of muscle, and the tunica externa for anchor to organs. The MyoD-expressing muscle is developmentally more similar to skeletal muscle than to heart muscle.
In fish
There was great debate as to whether teleost fish have a lymphatic system. Current evidence shows that they likely have a "primitive" version. They do not seem to have lymph hearts, instead using blood pressure to move lymph.
Lungfish, which are more related to tetrapods, use many "micropumps" to move lymph around, reaching densities as high as 100 per cubic millimeter in the fins of South American lungfish.
In reptiles and birds
Lymph heart size and pump rate
These hearts vary in size from microscopic in lungfish to an estimated 20-liter capacity in some of the largest dinosaurs. In newts, frogs and turtles they pump at rates higher than the blood heart and the volumes pumped are quite remarkable. In toads and frogs, this volume can amount to about 1/50 the output of blood from the heart. In amphibians, lymph hearts lie at vein junctions. Frogs and salamanders have 10 to 20 lymph hearts, while caecilians have more than 100. Conversely, reptiles have a single pair of lymph hearts in the pelvic area. In flightless (ratite) birds, the lymph heart function is less clear and the two almond-sized hearts located near the spinal column close to the hip joint are thought to be involved in inflating and deflating the phallus with lymph, which is of a significant size in both sexes of emus and ostriches.
References
Animal physiology | Lymph heart | Biology | 887 |
67,254,496 | https://en.wikipedia.org/wiki/Locomotive%20syndrome | Locomotive syndrome is a medical condition of decreased mobility due to disorders of the locomotor system. The locomotor system comprises bones, joints, muscles and nerves. It is a concept put forward by three professional medical societies in Japan: the Japanese Society for Musculoskeletal Medicine, the Japanese Orthopaedic Association, and the Japanese Clinical Orthopaedic Association. Locomotive syndrome is generally found in the ageing population as locomotor functions deteriorate with age. Symptoms of locomotive syndrome include limitations in joint mobility, pain, balance disorder, malalignment and gait abnormality. Locomotive syndrome is commonly caused by chronic locomotive organ diseases. Diagnosis and assessment of locomotive syndrome is done using several tests such as the stand-up and two-step tests. The risk of having locomotive syndrome can be decreased via adequate nutrition, attainment of an exercise habit and being active.
History
In 2000, the Government of Japan established the insurance system Long-term Care Insurance to resolve the issue of the drastic increase of Japanese elderly people in need of nursing care, which imposed a heavy financial burden on the Japanese society. Locomotive system disorders took up approximately a quarter of the need for long-term nursing care in Japan.
Subsequently, three professional Japanese medical societies, the Japanese Society for Musculoskeletal Medicine, the Japanese Orthopaedic Association, and the Japanese Clinical Orthopaedic Association, put forward the idea of locomotive syndrome in 2007 with the aim of enhancing public awareness of locomotive syndrome and calling for plans for its management.
Epidemiology
Globally, locomotive syndrome prevalence is estimated to be approximately 10%.
Researchers have tried to determine whether there are variations in locomotive syndrome prevalence between sexes. Two surveys in Japan showed that locomotive syndrome prevalence in men was lower than that in women. A 2010 nationwide survey with participation of 4500 subjects in Japan showed the estimated locomotive syndrome prevalence for men and women to be 7.9% and 12.3% respectively. Moreover, another nationwide survey with 5162 subjects in 2014 showed the prevalence for men and women to be 10.8% and 12.9% respectively. Contrarily, a different study in Japan with participation of 963 subjects indicated that the difference in locomotive syndrome prevalence between men and women was not significant.
The prevalence of locomotive syndrome increases as people become older, with the highest in those aged 70 or above at 16%. Locomotive syndrome prevalence in people with chronic pain was eight times higher than that of the general population. In addition, the number of orthopaedic surgery treatments in need of hospitalisation drastically rises after age 50 and reaches a peak after the age of 70.
Signs and symptoms
The main components in the locomotive system include intervertebral disks, joints, bones, nervous and muscular system. The deterioration of locomotive components leads to symptoms such as pain, limitation in joint mobility, malalignment, balance disorder and gait abnormality. Syndrome progression leads to reduced ability to perform activities of daily living independently and eventually results in decreased quality of life and necessity of nursing care. People with locomotive syndrome may not be able to accomplish everyday tasks such as putting socks on while standing on one leg, doing moderately intensive house chores, carrying home 5 pounds of shopping and walking nonstop for 15 minutes. They may also slip around or trip up the house and need to hold on to handrails for support whilst climbing up the stairs.
Degenerative changes in the main components of the locomotive system begin before middle age. Generally in the initial stages, the progression is slow and asymptomatic. The symptoms only become obvious when pathological degeneration changes become advanced.
Causes and mechanism
Locomotive syndrome is generally caused by decreased strength of muscles and balance related to ageing and locomotive conditions such as osteoarthritis, osteoporosis and spondylosis. Muscle degeneration becomes more common in people aged 50 or above. On average, they lose 3% of their muscle strength annually. This hinders their ability to undertake several physical routine activities. Elderly people with osteoporosis and frailty have a higher risk of hip, vertebra, distal radius and humerus fractures. These fractures can cause pain at the fracture site. For osteoarthritis, which is a medical condition of the synovial joints, the abrasion and breakdown of hyaline cartilage and underlying bone can cause joint pain and thus limit movement. For spondylosis, pressure on the spine wears out the intervertebral discs and disfigures the bone, which causes serious pain and leads to restriction of motion.
Specifically in women, locomotive syndrome may be caused by reduced levels of bone density and physical activity that usually happen after menopause. Bone density level decreases as the level of oestrogen, a hormone essential for healthy bones, drops after menopause. This causes more bone resorption than formation. Additionally, women tend to have smaller bones and lower bone mass than men, which further increases the risk of locomotive syndrome. They may also suffer from insufficient nutrition due to dieting in order to be thin, which further contributes to weak bones.
Diagnosis and assessment
The diagnosis and assessment of locomotive syndrome are done using the short test battery for locomotive syndrome (STBLS) established by the JOA. STBLS consists of the stand-up test, the two-step test and the 25-question Geriatric Locomotive Function Scale (GLFS-25). Results from STBL serve as a guide to assess the risk, presence and degree of locomotive syndrome. There are two stages of locomotive syndrome. Stage 1 indicates the beginning of mobility function decline and stage 2 indicates a progression of mobility function decline. Individuals with locomotive syndrome are categorised into one of the two stages depending on the scores of the three tests.
Stand-up test
The stand-up test examines and measures the vertical movement ability of the body and the muscle strength of the lower extremities. The test evaluates the ability to stand with one or both legs from stools of heights 10, 20, 30 and 40 cm. The difficulty level increases in order of decreasing stool height and when using one leg instead of two. The test is usually performed in increasing order of difficulty starting from standing up using both legs from a 40 cm high stool. The trial is successful if the individual can stand and hold their position for more than three seconds. The inability to stand up from a 40 cm tall stool using one leg is an indicator of stage 1 locomotive syndrome while the inability to stand up from a 20 cm tall stool using both legs is an indicator of stage 2 locomotive syndrome.
Two-step test
The two-step test evaluates balance and walking ability by assessing gait speed and maximal step length. The test involves individuals taking two steps forward at maximum stride without losing balance and then standing still on both feet for more than three seconds. The distance covered by the two steps is measured and divided by the individual's height to obtain the two-step value which correlates with walking speed. The test is done twice and the highest value is noted. A score of less than 1.3 signifies stage 1 locomotive syndrome and a score of less than 1.1 signifies stage 2 locomotive syndrome.
GLFS-25
The GLFS-25 is a self-administered questionnaire that evaluates pain, movement-related difficulty, social activity, cognitive status and daily activities of the middle-aged and elderly population. The scale consists of 25 questions referring to experiences in the preceding month that addresses four areas. This includes 4 questions about pain, 16 questions about pain during activities of daily living, 3 questions about social functions and 2 questions about mental health status. Each question is scored on a 5-point scale from 0 which indicates no impairment to 4 which indicates severe impairment. The total score which ranges from 0 to 100 serves as a quantitative evaluation of the difficulties and disabilities in activities of daily living related to the locomotor system. A GLFS-25 score of 7 or more is indicative of stage 1 locomotive syndrome and a score of 16 or more is indicative of stage 2 locomotive syndrome.
Prevention and management
Strategies for preventing the onset and progression of locomotive syndrome include regular exercise and appropriate nutritional intake.
As exercise has been proven to significantly improve motor function and limit the decline of functional capacity, habitual exercise is the main method for locomotive syndrome prevention and improvement. The JOA proposed a set of exercises called locomotion training or locotra aimed for the improvement of physical function in the middle-aged and elderly population. Locotra consists of single-leg standing with eyes open, squats, heel raises and front lunges. These exercises help improve balance and muscle strength of the lower extremities which are vital for activities of daily living.
Single-leg standing
Single-leg standing with eyes open is an exercise that effectively improves balance and prevents falls. Individuals are required to raise one foot by 5–10 cm with their eyes open for 1 minute. The exercise is to be done near a stable surface such as a desk to prevent falling. Three repetitions for each leg daily is recommended.
Squatting
Squatting has been proven to improve strength and balance of the lower body and independence of activities of daily living. Squatting involves lowering the torso from standing position and returning to the upright position. The proper squatting technique requires individuals to maintain the position of knees over the toes and the knee flexion angle below 90°. Three sets of 5-6 repetitions are recommended daily.
Heel raises
Heel raises involve raising and lowering the heels while standing on the balls of the feet. This exercise strengthens the triceps muscles of the lower extremities associated with gait speed and fall risk. Two or three sets of 10-20 repetitions are recommended daily.
Front lunges
Front lunges are performed by lowering the upper body slowly and bringing the body back up while keeping one foot forward in line with the back foot. Front lunges improve muscle strength, balance and flexibility of the lower extremities as most of the lower limb muscles are activated during the exercise. Two or three sets of 5-10 repetitions daily are recommended.
Nutrition
In addition to exercise, nutritional improvement helps in the improvement and sustainment of motor function. Maintaining a well-balanced diet and healthy body weight help keep the musculoskeletal system healthy. Overnutrition increases the risk of locomotive syndrome as extra body weight puts added strain on the back and knees. Oppositely, undernutrition reduces bone and muscle mass, leading to osteoporosis and sarcopenia. The JOA recommends eating three proper meals a day to obtain a balanced mix of the five major nutrients: carbohydrates, fat, protein, vitamins and minerals. These nutrients are essential for the proper maintenance of the locomotor system. A steady supply of calcium, protein, vitamin D and vitamin K are required for the constant regeneration of bones. 700–800 mg of calcium per day is recommended to prevent osteoporosis. Protein supplementation has been shown to have additive effects to exercise intervention. Vitamin D enhances calcium absorption in the gut and vitamin K plays a role in the formation of bones and the maintenance of bone quality. Other important nutrients involved in bone formation include magnesium, folic acid, vitamin B6 and vitamin B12. On the other hand, overconsumption of sodium, phosphate and caffeine hinders calcium absorption.
Protein and vitamin B6 also help in the formation and maintenance of muscles.
References
Musculoskeletal system
Syndromes affecting bones | Locomotive syndrome | Biology | 2,367 |
74,977,871 | https://en.wikipedia.org/wiki/Nessum | Nessum, previously HD-PLC (short for 'High Definition Power Line Communication'), is a communication technology standardized by the Institute of Electrical and Electronics Engineers (IEEE). It is standardized as IEEE 1901-2020.
The standard is to be used to communicate data over wired and wireless media using high frequencies between ~500kHz and ~56 MHz bands. The Nessum Alliance is the certifying body for compatibility between Nessum-based communication devices.
Overview
Nessum offers two types of communication: wired (Nessum WIRE) and wireless (Nessum AIR).
Wired communication
Nessum WIRE can be used for various types of wires such as power lines, twisted pair wiring, coaxial cables, and telephone lines. The communication distance can range between tens of meters to several kilometers depending on the use case. In addition, when an automatic relay function called multi-hop (ITU-T G.9905) is utilized, a maximum of 10 stages of relay is possible to extend the range, and support various network topologies (Ring, Star, Bus, MESH). With a maximum physical speed of 1 Gbps and effective throughput ranging from several Mbps to several hundred Mbps, this technology is used to reduce network construction costs and complexity by utilizing the existing lines or dedicated lines.
Wireless communication
Nessum wireless communication is called Nessum AIR. It uses magnetic field communication for short range communication. The communication distance can be controlled in the range of a few centimeters to 100 centimeters. Maximum physical speed is 1 Gbps, with an effective speed of 100 Mbps.
Technical overview
Physical layer (PHY)
The physical layer uses Wavelet OFDM (Wavelet Orthogonal Frequency Division Multiplexing), while a guard interval is required in ordinary OFDM systems. The Wavelet OFDM system eliminates the guard interval and increases the occupancy rate of the data portion, thereby achieving high efficiency. In addition, due to the bandwidth limitation of each subcarrier, the level of sidelobes is set low, which facilitates the formation of spectral notches. This minimizes interference with existing systems and allows for flexible compliance with frequency utilization regulations. Furthermore, Pulse-Amplitude Modulation (PAM) is used for each subcarrier, and the optimal number of modulation multi-levels is set according to the conditions of the transmission path, thereby improving transmission efficiency. The frequency band used can be selected from among standardized patterns.
Data link layer (MAC)
The data link layer manages quality of service and other control functions using control frames "beacons" broadcast periodically by the parent to all terminals in the network. The basic media access methods are Carrier-Sense Multiple Access with Collision Avoidance (CSMA/CA) and Dynamic Virtual Token Passing (DVTP), which dynamically assign transmission rights to terminals in the network and avoid collisions, The system uses a collision avoidance mechanism.
Specification and features
There are essentially two different types of HD-PLC: HD-PLC Complete and HD-PLC Multi-hop. They are incompatible.
HD-PLC Complete
Source:
This is for high speed applications such as TV, AV, and surveillance cameras.
The major technical features include:
IEEE 1901 full compliant
QoS by the priority control
CSMA/CA and DVTP(Dynamic Virtual Token Passing) supported
Concurrent multi-AV stream, VoIP, and file transfer and file transfer supported using IP packet classification
Multi-network access at priority CSMA/CA with network synchronization
HD-PLC Multi-hop
Source:
This is for long-distance applications such as smart meter, building network, factory, energy management, and IoT devices.
The major technical features include:
ITU-T G.9905 multihop technology
Common features
Source:
Uplinking/downlinking through 432 of 26 MHz (between 1.8 MHz and 28 MHz) bandwidth subcarriers with Wavelet OFDM
Maximum 240 Mbit/s PHY rate
Multilevel modulation for each subcarrier which suits the properties of the power line transmission channel and allows for the best transmission speed
Subcarrier masking with the arbitrary number which can comply with the rules in each country
Forward error correction (FEC) which enables effective frame transmission
Channel estimation launch system with change detector for cycle and transmission channel
HD-PLC network bridging compatible to Ethernet address system
Advanced encryption with 128 bit AES
4th-generation HD-PLC (HD-PLC Quatro Core technology)
Source:
We now come to communication speed issues like high-definition video images (4K/8K) or in some cases multi hop technology is not enough to reach an isolated and distant PLC terminal. HD-PLC Quatro Core has been designed to solve these problems. This technology is an improvement on the conventional HD-PLC in both communication distance and speed. It achieves to double conventional HD-PLC's communication distance by adopting a communication band of 1/2 or 1/4 of conventional HD-PLC band and achieves to offer a maximum physical line transmission rate of 1 Gbit/s by using an expanded communication band 2 or 4 times the conventional HD-PLC band.
This evolution of the standard therefore offers either an extended range in a larger building, at the cost of a lower data rate, or a higher data rate, but achievable over shorter distances than in the previous version of the standard.
Use cases
There are a few strengths of using HD-PLC technology on existing wires.
Expectable higher speed performance
Cost reduction on network construction by existed infrastructure
Support the area where the radio waves is difficult to be reached
Wire saving by sharing power lines and communication lines
Typical use case include:
HVAC systems
Building Automation
Photovoltaic (solar) panel communications
Smart metering
Meter to grid communications
Smart street lighting
Surveillance camera systems
Video entry systems
Communications in tunnels
Robot wiring optimisation
Nessum Alliance
Nessum Alliance was established in September 2007 as a voluntary association, originally under the name of "HD-PLC Alliance". In October 2023, the HD-PLC Alliance was renamed the Nessum Alliance.
Nessum Alliance is a certifying body for compatibility between communication devices that comply with the international standard IEEE 1901-2020. Associated organisations are the Japanese Telecommunication Technology Committee (TTC) The Taiwanese Industrial Technology Research Institute and the IEEE Standards Association.
At the outset of 2025 the Nessum Alliance listed 37 member companies and organisations.
History
This technology is based on HD-PLC, a type of power line communication developed by Panasonic in the early 2000s. HD-PLC was developed for room-to-room transmission of audio and video data at the time, but later began to be used not only for power lines but also for coaxial lines and twisted pair lines, and even for wireless communication. The name "power line communication" did not match the reality of the situation. In September 2023, Panasonic Holdings Corporation changed the name of HD-PLC to Nessum.
See also
BACnet
Power line communication
HomePlug
G.hn
HomePNA
IEEE 1901
KNX
LonWorks
References
External links
Nessum Alliance
Computer networking | Nessum | Technology,Engineering | 1,443 |
5,684,961 | https://en.wikipedia.org/wiki/Mothers%20against%20decapentaplegic%20homolog%206 | SMAD family member 6, also known as SMAD6, is a protein that in humans is encoded by the SMAD6 gene.
SMAD6 is a protein that, as its name describes, is a homolog of the Drosophila gene "mothers against decapentaplegic". It belongs to the SMAD family of proteins, which belong to the TGFβ superfamily of modulators. Like many other TGFβ family members SMAD6 is involved in cell signalling. It acts as a regulator of TGFβ family (such as bone morphogenetic proteins) activity by competing with SMAD4 and preventing the transcription of SMAD4's gene products. There are two known isoforms of this protein.
Nomenclature
The SMAD proteins are homologs of both the drosophila protein, mothers against decapentaplegic (MAD) and the C. elegans protein SMA. The name is a combination of the two. During Drosophila research, it was found that a mutation in the gene MAD in the mother repressed the gene decapentaplegic in the embryo. The phrase "Mothers against" was added as a humorous take-off on organizations opposing various issues e.g., Mothers Against Drunk Driving, or MADD; and based on a tradition of such unusual naming within the gene research community.
Disease associations
Heterozygous, damaging mutations in SMAD6 are the most frequent genetic cause of non-syndromic craniosynostosis identified to date.
Interactions
Mothers against decapentaplegic homolog 6 has been shown to interact with:
HOXC8,
MAP3K7,
Mothers against decapentaplegic homolog 7,
PIAS4, and
STRAP.
References
Further reading
Transcription factors
Developmental genes and proteins
MH1 domain
MH2 domain
Human proteins | Mothers against decapentaplegic homolog 6 | Chemistry,Biology | 381 |
151,488 | https://en.wikipedia.org/wiki/Michael%20Dell | Michael Saul Dell (born February 23, 1965) is an American billionaire businessman and investor. He is the founder, chairman, and CEO of Dell Technologies, one of the world's largest technology infrastructure companies.
He is the 10th-richest person in the world as of December 2024, according to Forbes Bloomberg Billionaires Index, with a net worth of $130 billion. As of October 2023, according to Forbes, approximately $50 billion of his net worth was derived from his 50% stake in Dell and 40% stake in VMware, with the rest being held by his family office DFO Management.
In January 2013 it was announced that he had bid to take Dell Inc. private for $24.4 billion in the biggest management buyout since the Great Recession. Dell Inc. officially went private in October 2013. The company once again went public in December 2018.
Early life and education
Dell was born in 1965 in Houston to a Jewish family. His parents were Lorraine Charlotte (née Langfan), a stockbroker, and Alexander Dell, an orthodontist. Michael attended Herod Elementary School in Houston. In a bid to enter business early, he applied to take a high school equivalency exam at age eight. In his early teens, he invested his earnings from part-time jobs in stocks and precious metals.
Dell purchased his first calculator at age seven and encountered an early teletype terminal in junior high. At age 15, after playing with computers at Radio Shack, he got his first computer, an Apple II, which he promptly disassembled to see how it worked. Dell attended Memorial High School in Houston, selling subscriptions to the Houston Post in the summer. Dell's parents wanted him to be a doctor and in order to please them, he took up pre-med at the University of Texas in 1983. Dell continued learning to target specific populations for newspaper subscriptions rather than just making cold calls. He discovered that people who were most likely to get a subscription were newlyweds and people moving to a new home. After collecting the contact information of this population from public records, he sent direct mail appeals and earned $18,000 in one year. He hired several employees, and after earning a gross profit of nearly $200,000 in his first year of business, Dell dropped out of the University of Texas at age 19.
Business career
While a freshman pre-med student at the University of Texas, Dell started an informal business putting together and selling upgrade kits for personal computers in Room 2713 of the Dobie Center residential building. He then applied for a vendor license to bid on contracts for the State of Texas, winning bids by not having the overhead of a computer store.
In January 1984, Dell believed that the potential cost savings of a manufacturer selling PCs directly had enormous advantages over the conventional indirect retail channel. In January 1984, Dell registered his company as "PC's Limited". Dell’s strategy was to sell directly to customers by manufacturing computers only after they were ordered. Operating out of a condominium, the business sold between $50,000 and $80,000 worth of PC upgrades, kits, and add-on components. In May, Dell incorporated the company as "Dell Computer Corporation" and relocated to a business center in North Austin. The company employed a few people as order takers, a few more to fill the orders, and, as Dell recalled, a manufacturing staff consisting of "three guys with screwdrivers sitting at six-foot tables". The venture's capitalization cost was $1,000. During the formative years of Dell Computer, Dell was mentored by Morton Meyerson.
In 1992, aged 27, he became the youngest CEO of a company ranked in Fortune magazine's list of the top 500 corporations. In 1996, Dell started selling computers over the Web, the same year his company launched its first servers. By March 1997, Dell Inc. reported about $1 million in sales per day from dell.com. In the first quarter of 2001, Dell Inc. reached a world market share of 12.8 percent, surpassing Compaq to become the world's largest PC maker. The metric marked the first time the rankings had shifted over the previous seven years. The company's combined shipments of desktops, notebooks and servers grew 34.3 percent worldwide and 30.7 percent in the United States at a time when competitors' sales were shrinking.
On March 4, 2004, Dell stepped down as CEO, but stayed as chairman of Dell Inc.'s board, while Kevin Rollins, then president and COO, became president and CEO. On January 31, 2007, Dell returned as CEO at the request of the board, succeeding Rollins.
In 2013, Michael Dell with the help of Silver Lake Partners, Microsoft, and a consortium of lenders took Dell, Inc. private. The deal was reportedly worth $25 billion and faced difficulties during its execution. Notable resistance came from Carl Icahn, but after several months he stepped aside. Michael Dell received a 75% stake in the company.
On October 12, 2015, Dell Inc. announced its intent to acquire the enterprise software and storage company EMC Corporation. At $67 billion, it has been labeled the "highest-valued tech acquisition in history". The acquisition was finalized September 7, 2016.
Penalty
In July 2010 Dell Inc. agreed to pay a $100 million penalty to settle SEC charges of disclosure and accounting fraud in relation to undisclosed payments from Intel Corporation. Michael Dell and former CEO Kevin Rollins agreed to pay $4 million each and former CFO James Schneider agreed to pay $3 million to settle the charges.
Accolades
Accolades for Dell include "Entrepreneur of the Year" (at age 24) from Inc. magazine; "Top CEO in American Business" from Worth magazine; "CEO of the Year" from Financial World, IndustryWeek and Chief Executive magazines. Dell also received the 1998 Golden Plate Award of the American Academy of Achievement and the 2013 Franklin Institute's Bower Award for Business Leadership.
Affiliations
Dell serves on the Foundation Board of the World Economic Forum, the executive committee of the International Business Council, the U.S. Business Council. He previously served as a member of the U.S. President's Council of Advisors on Science and Technology.
In April 2020, Governor Greg Abbott named Dell to the Strike Force to Open Texas – a group "tasked with finding safe and effective ways to slowly reopen the state" during the COVID-19 pandemic. He also serves as an advisor on the COVID-19 Technology Task Force, a technology industry coalition founded in March 2020 collaborating on solutions to respond to and recover from the COVID-19 pandemic.
Writings
Dell's 1999 book, Direct from Dell: Strategies That Revolutionized an Industry (by HarperBusiness), is an account of his early life, his company's founding, growth and missteps, as well as lessons learned. The book was written in collaboration with Catherine Fredman.
Dell's second book, Play Nice But Win: A CEO's Journey from Founder to Leader (by Portfolio), is a story of inside battles that defined him as a leader. The book was written in collaboration with James Kaplan.
Personal life
Dell married Susan Lieberman on October 28, 1989, in Austin, Texas; the couple reside there with their four children.
Wealth and philanthropy
In 1998, Dell founded MSD Capital L.P., later renamed DFO Management, to manage his family's investments. Michael and Susan Dell established the Michael & Susan Dell Foundation in 1999, which focuses on causes related to health and education.
References
Further reading
Koehn, Nancy F. Brand New: How Entrepreneurs Earned Consumers' Trust from Wedgwood to Dell (2001) pp 257–306.
Magretta, Joan. "The power of virtual integration: An interview with Dell Computer's Michael Dell." Harvard Business Review (1998): pp-73+. online
External links
1965 births
Living people
20th-century American businesspeople
21st-century American businesspeople
21st-century American Jews
American billionaires
American business writers
American chief executives of manufacturing companies
American commodities traders
American computer businesspeople
American financiers
American investors
American male non-fiction writers
American nonprofit businesspeople
American people of German-Jewish descent
American philanthropists
American political fundraisers
American businesspeople in real estate
American stock traders
American technology chief executives
American technology company founders
American technology writers
Businesspeople from Texas
Dell people
Jewish American non-fiction writers
Memorial High School (Hedwig Village, Texas) alumni
Private equity and venture capital investors
Texas Republicans
University of Texas at Austin alumni
Writers from Texas
Benjamin Franklin Medal (Franklin Institute) laureates | Michael Dell | Technology | 1,782 |
58,622,753 | https://en.wikipedia.org/wiki/Aspergillus%20asperescens | Aspergillus asperescens is a species of fungus in the genus Aspergillus. It is from the Nidulantes section. The species was first described in 1954. It has been isolated from soil from a cave in England.
Growth and morphology
A. asperescens has been cultivated on both Czapek yeast extract agar (CYA) plates and Malt Extract Agar Oxoid® (MEAOX) plates. The growth morphology of the colonies can be seen in the pictures below.
References
asperescens
Fungi described in 1954
Fungus species | Aspergillus asperescens | Biology | 121 |
26,747,160 | https://en.wikipedia.org/wiki/Bihari%E2%80%93LaSalle%20inequality | The Bihari–LaSalle inequality was proved by the American mathematician
Joseph P. LaSalle (1916–1983) in 1949 and by the Hungarian mathematician
Imre Bihari (1915–1998) in 1956. It is the following nonlinear generalization of Grönwall's lemma.
Let u and ƒ be non-negative continuous functions defined on the half-infinite ray [0, ∞), and let w be a continuous non-decreasing function defined on [0, ∞) and w(u) > 0 on (0, ∞). If u satisfies the following integral inequality,
where α is a non-negative constant, then
where the function G is defined by
and G−1 is the inverse function of G and T is chosen so that
References
Differential equations
Inequalities | Bihari–LaSalle inequality | Mathematics | 163 |
70,197,345 | https://en.wikipedia.org/wiki/Christoph%20Weder | Christoph Weder is the former director of the Adolphe Merkle Institute (AMI) at the University of Fribourg, Switzerland, and a professor of polymer chemistry and materials. He is best known for his work on stimuli-responsive polymers, polymeric materials that change one or more of their properties when exposed to external cues. His research is focused on the development, investigation, and application of functional materials, in particular stimuli-responsive and bio-inspired polymers.
Education and career
Christoph Weder was born on July 30, 1966. He began elementary school in Mülheim a. Main, Germany, in 1972 before moving to Thalwil, Switzerland, in 1974, where he completed elementary and secondary school. He then attended the high school Kantonsschule Enge in Zurich, from which he graduated in 1985. Following in the footsteps of his father, who was also a polymer chemist, Weder studied chemistry at the Swiss Federal Institute of Technology (ETH Zurich) in Zurich, where he received his diploma in chemistry in 1990. He then joined the research group of Professor Ulrich W. Suter as a doctoral student and in 1994 was awarded the degree of Doctor of Natural Sciences for his dissertation “New Polyamides with Stable Nonlinear Optical Properties.” While at ETH, Weder was also trained as a chemistry teacher and received his teaching certification in 1992. With a fellowship from the Swiss National Science Foundation, Weder then spent one year as a postdoctoral research fellow in the Department of Chemistry at the Massachusetts Institute of Technology, where he worked under the guidance of then-provost Mark S. Wrighton.
Weder returned to the Department of Materials of ETH Zurich in 1995, where he joined the group of Professor Paul Smith and continued to work on photofunctional polymers. Based on his habilitation thesis entitled “Polarizing Light with Polymers,” Weder received his habilitation and, bestowed with the venia legendi, became an independent lecturer in 1999. In 2001, Weder left ETH and joined Case Western Reserve University in Cleveland, Ohio, as an associate professor in the Department of Macromolecular Science and Engineering. He was promoted to professor in 2007, and in 2008 was named the F. Alex Nason Professor.
In 2009, Weder returned to Switzerland and joined the Adolphe Merkle Institute (AMI) as Professor of Polymer Chemistry and Materials. AMI, which was founded in 2008 thanks to a gift from Adolphe Merkle, is an interdisciplinary research center that focuses on fundamental and application-oriented research in soft nano- and materials sciences. In January 2010, Weder was appointed as the institute’s director, serving until April 2022.
Weder led a team that was awarded a grant from the Swiss National Science Foundation (SNSF) to establish the National Competence Center in Research (NCCR) Bio-Inspired Materials. He served as the center’s director from its launch in 2014 until 2020. The NCCRs are a research instrument of the Swiss National Science Foundation (SNSF) that aim to strengthen research in areas of strategic importance for the future of Swiss science, business and society.
Weder remains an adjunct professor at CWRU and has served as a visiting professor at Chulalongkorn University in Bangkok, Thailand since 2003. He serves as an Associate Editor of ACS Macro Letters and was a co-editor of the RSC Book Series Polymer Chemistry from 202-2021.
Weder has co-authored more than 300 peer-reviewed articles in scientific journals and over twenty book chapters. He also edited two books. As of March 2022, Weder has an h-index of 87 and his works have been cited more than 27,000 times.
Weder is a co-inventor of more than twenty patent families that protect technologies such as light-polarizing security features, mechanochromic materials, sea-cucumber inspired dynamic mechanical polymer nanocomposites, stimuli-responsive supramolecular polymers, materials for optical upconversion, shape memory polymers, and optical data storage systems. He was a co-founding board member of the ETH-spinoff company Omlidon Technologies, LLC (1999–2002), and served on the board of directors of Gel Instrumente AG (1994–2006).
Weder is the recipient of a 3M Non-Tenured Faculty Award, a DuPont Young Professor Award, an NSF Special Creativity Award, and the Case School of Engineering Award. He was awarded a prestigious European Research Council (ERC) Advanced Grant, and is a Fellow of the American Chemical Society’s Division of Polymer Chemistry. In 2017, he was nominated as a member of the Swiss Academy of Technical Sciences "in recognition of his pioneering work in the development of nanomaterials through combination of fundamental research and practical applications as well as his contribution to the successful establishment of the Adolphe Merkle Institute".
Weder is married and has three children.
Research
Weder’s early research activities in the 1990s focused on polymers with special optical properties. This involved the development of nonlinear optical polymers and investigations of the structure-property relationships of photoluminescent poly(p-phenylene ethynylene)s. He demonstrated the usefulness of these semiconducting polymers as the active layer in polymer-based light-emitting diodes. His group also exploited the possibility to orient such rod-like molecules to create fluorescent materials that display linearly polarized absorption and emission. Such materials formed the basis of security features that Weder’s group developed, which were used as an anti-counterfeiting element in security paper. His team also discovered a light-polarizing energy transfer effect that can be used to produce highly efficient fluorescent polarizers. Such elements are useful in display and other applications.
Weder’s research focus turned to stimuli-responsive polymers shortly after he moved to CWRU in 2001. In 2002, Weder’s research lab developed a novel method to create polymeric materials that change their fluorescence color upon deformation. Recognizing the potential for practical applications this effect had, Weder established a research program to develop polymers that translate mechanical forces into optical signals, which is still active today, and shortly thereafter, mechanochromic polymers began to attract widespread interest. Most of the mechanochrochromic materials reported by Weder’s group in the following two decades operate on the basis of the same general transduction principle, which involves changing the interactions among optically active motifs in response to mechanical deformation. Recent discoveries include the development of new mechanically responsive motifs or “mechanophores” based on rotaxanes and loop-forming dye pairs.
Controlling the interactions between molecular or nanoscale building blocks through an external stimulus has become one of Weder’s main design tools for the creation of stimuli-responsive polymers. In 2008, in collaboration with his colleague Stuart Rowan, Weder introduced stimuli-responsive mechanically adaptive polymer nanocomposites whose architecture and function was inspired by sea cucumbers. The mechanical properties of these materials, which were made by incorporating nanocellulose crystals as a reinforcing filler into polymer matrices, depend on the interactions among the cellulose nanocrystals (CNCs), and can be regulated by an external stimulus. The approach was initially used to create mechanically morphing implant materials, which soften upon exposure to physiological conditions. This work led to sustained research efforts in Weder’s group on bio-inspired mechanically morphing polymers, the development of protocols for the processing of CNC/polymer nanocomposites, and the development of new cellulose-based nanocomposites. Adaptive polymers that show such mechanical morphing upon exposure to physiological conditions were reported to increase the functionality of cortical implants.
The possibility to heal defects in polymeric materials can increase the reliability and durability of polymer products. In 2011, also in collaboration with Rowan, Weder demonstrated that the UV-light induced temporary disassembly of metallosupramolecular polymers can be used to heal defects in these materials. Expanding on this concept, Weder’s team introduced light healable nanocomposites, and modified the structure to include different binding motifs and architectures, for example glassy hydrogen-bonded supramolecular polymer networks. His group also used this approach to develop adhesives with the capability to bond or debond on demand. Weder’s group sought to push the mechanical properties of supramolecular polymers towards those of conventional thermoplastics. In 2019, his team demonstrated that it is possible to toughen stiff but brittle glassy supramolecular polymer networks by forming blends with a rubbery component. More recent versions of such materials were shown to be healable and to display property combinations that are comparable to some conventional plastics.
References
1966 births
Living people
21st-century Swiss chemists
Massachusetts Institute of Technology alumni
20th-century Swiss chemists
Polymer chemistry
Polymer scientists and engineers
ETH Zurich alumni
Christoph Weder | Christoph Weder | Chemistry,Materials_science,Engineering | 1,856 |
5,203,398 | https://en.wikipedia.org/wiki/Crossed%20ladders%20problem | The crossed ladders problem is a puzzle of unknown origin that has appeared in various publications and regularly reappears in Web pages and Usenet discussions.
The problem
Two ladders of lengths a and b lie oppositely across an alley, as shown in the figure. The ladders cross at a height of h above the alley floor. What is the width of the alley?
Martin Gardner presents and discusses the problem in his book of mathematical puzzles published in 1979 and cites references to it as early as 1895. The crossed ladders problem may appear in various forms, with variations in name, using various lengths and heights, or requesting unusual solutions such as cases where all values are integers. Its charm has been attributed to a seeming simplicity which can quickly devolve into an "algebraic mess" (characterization attributed by Gardner to D. F. Church).
Solution
The problem description implies that that and , that and that where A and B are the heights of the walls where sides of lengths b and a respectively lean (as in the above graph).
Both solution methods below rely on the property that , , and satisfy the optic equation, i.e. , which can be seen as follows:
Divide the baseline into two parts at the point where it meets , and call the left and right parts and respectively. The angle where meets is common to two similar triangles with bases and respectively. The angle where meets is common to two similar triangles with bases and respectively. This tells us that
which we can then re-arrange (using ) to get
First method
Two statements of the Pythagorean theorem (see figure above)
and
can be subtracted one from the other to eliminate w, and the result can be combined with with alternately A or B solved out to yield the quartic equations
These can be solved algebraically or numerically for the wall heights A and B, and the Pythagorean theorem on one of the triangles can be used to solve for the width w.
Second method
The problem may be reduced to the quartic equation , which can be solved by approximation methods, as suggested by Gardner, or the quartic may be solved in closed form by Ferrari's method. Once x is obtained, the width of the alley is readily calculated. A derivation of the quartic is given below, along with the desired width in terms of the quartic solution. Note that the requested unknown w does not appear directly in most of the derivation.
From we get
Using the Pythagorean theorem, we can see that
and
By isolating on both equations, we see that
which can be rearranged and factored into
Square (Eq. 2) and combine with (Eq. 1):
Rearrange to get
Then
Now, combine with (Eq. 1):
Finally,
Let
Then
(same as Eq. 3 with the sides reversed)
The above fourth-power equation can be solved for x using any available method. The width of the alley is then found by using the value found for x: The identity
can be used to find A, and w can finally be found by
A quartic equation has four solutions, and only one solution for this equation matches the problem as presented. Another solution is for a case where one ladder (and wall) is below ground level and the other above ground level. In this case the ladders do not actually cross, but their extensions do so at the specified height. The other two solutions are a pair of conjugate complex numbers. The equation does not have the ladder lengths explicitly defined, only the difference of their squares, so one could take the length as any value that makes them cross, and the wall spacing would be defined as between where the ladders intersect the walls.
As the wall separation approaches zero, the height of the crossing approaches This is because (proven at the start) implies and as w goes to zero, b goes to A and a goes to B according to the top diagram.
As the solutions to the equation involve square roots, negative roots are equally valid. They can be interpreted as both ladders and walls being below ground level and with them in opposing sense, they can be interchanged.
The complex solutions can be interpreted as wall A leaning to the left or right and wall B below ground, so the intersection is between extensions to the ladders as shown for the case The ladders a and b and are not as specified. The base w is a function of A, B, and h, and the complex values of A and B can be found from the alternative quartic
with D being for one wall and for the other (±5 in the example). Note that the imaginary solutions are horizontal and the real ones are vertical. The value D is found in the solution as the real part of the difference in the squares of the complex coordinates of the two walls. The imaginary part = 2XaYa = 2XbYb (walls a and b). The short ladder in the complex solution in the 3, 2, 1 case appears to be tilted at 45 degrees, but actually slightly less with a tangent of 0.993. Other combinations of ladder lengths and crossover height have comparable complex solutions. With combination 105, 87, 35 the short ladder tangent is approximately 0.75.
Integer solutions
There are solutions in which all parameters are integers. For example, (a, b, A, B, w1, w2, w, h) = (119, 70, 42, 105, 16, 40, 56, 30). Such solutions involve Pythagorean triples for the two right triangles with sides (A, w, b) and (B, w, a) and integer solutions of the optic equation
Application to paper folding
The optic equation of the crossed ladders problem can be applied to folding rectangular paper into three equal parts:
+ = ∴ 2 + 1 = ∴ h = =
One side (left in the illustration) is partially folded in half and pinched to leave a mark. The intersection of a line from this mark to an opposite corner (red) with a diagonal (blue) is exactly one third from the bottom edge. The top edge can then be folded down to meet the intersection.
It is also exactly one third horizontally from the left edge; folding the right edge to meet the intersection lets the paper be folded into thirds lengthwise.
Similarly, folding the left side twice to get quarters lets one fold the sheet into five equal parts:
+ = ∴ 4 + 1 = ∴ h′ = =
and folding it thrice to get eights lets one fold the sheet into nine equal parts, etc.:
+ = ∴ 8 + 1 = ∴ h″ = =
Extended crossed ladders theorem
The crossed ladders theorem was extended to crossed ladders within a triangle. In 2002, Harold Joseph Stengel (1947–2007), an American secondary school teacher of mathematics, proved the extended theorem.
Let AC be the base of a triangle ABC. Let ladder (line) AD have its foot at A and intersect BC at D; likewise, let ladder CE have its foot at C and intersect AB at E. Let AD intersect CE at F. Extend parallel lines from the points E, B, F, and D, intersecting AC at the points I, G, J, and H, respectively. Then
+ = +
whence it follows that
+ = + .
See also
Right trapezoid, the quadrilateral with vertices at the tops and bottoms of the two ladders
References
External links
Crossed Ladders Theorem by Jay Warendorff, the Wolfram Demonstrations Project.
Solving the crossing ladders puzzle (with Python, GNU GSL, Octave, Maxima and Sage).
Puzzles
Elementary geometry | Crossed ladders problem | Mathematics | 1,573 |
3,502,530 | https://en.wikipedia.org/wiki/Trona%20Railway | The Trona Railway is a short-line railroad owned by Searles Valley Minerals. The TRC interchanges with the Lone Pine Subdivision of the Union Pacific Railroad (former Southern Pacific Transportation Company) at Searles, California.
History
The railroad was built by the American Trona Company in 1914, to bring the mining company's potash to an interchange with the Southern Pacific Railroad. The company and its Trona Railway has had various subsequent owners, including American Potash & Chemical Corporation, Kerr-McGee Corporation, IMC Global, Sun Capital, LLC, before the current ownership of Searles Valley Minerals, Inc. On Dec. 27 2007, Karnavati Holdings, a subsidiary of Nirma Limited, acquired all of Searles Valley Minerals, Inc.
In the 1920s, the Epsom Salts Monorail delivered epsomite to the Trona Railway at Magnesium Siding, about south of Trona. This unique system extended eastwards into the Owlshead Mountains, was in use from 1924 to 1926, and was dismantled in the late 1930s.
Construction
The idea of building a standard gauge railroad to replace mule-drawn wagons came from Stafford W. Austin, the receiver of the American Trona Corporation. The railroad would connect Searles Valley with a lower cost connection to the markets within the United States and to ocean ports for exports. On 27 September 1913 the wife of Joseph Hutchinson broke ground with an old fashioned plow, to start the construction of Trona Railroad. The work force of 400 included American, Chinese, Greek, Hindu, Mexican, Irish, Norwegian and Swedish workers. They finished the task within 6 months despite battling occasional sandstorms. The construction was event-free, apart from one runaway tank car down the track from Searles Station. This struck the construction train and derailed several cars without causing injuries. The construction of the track was completed by end of March 1914, and the first excursion was conducted in May 1914.
Steam locomotives
The operation began with two new oil-fired Baldwin 2-8-0 steam locomotives. The locomotives weighed 104 tonnes each and their boilers produced steam at 200 pounds pressure. When they were coupled together, they had a combined pulling capacity of 500 tons.
Passenger service
In addition to carrying inbound fuel oil and outbound fertilizer and chemical products from the new chemical plants in Searles Valley, the Trona Railway also carried passengers to and from Trona. Regular passenger services continued until 1937. A self-propelled coach for pupils of Westend, South Trona and Borosolvay to attend the school in Trona ran up to 1941. This coach was sold in 1941 to the California Western Railroad as their number M-200 for the Skunk Train from Willits, California, to Fort Bragg, California. It was sold to the Niles Canyon Railway in 1975.
World War I
In 1914 Searles Lake was one of only two known potash deposits outside of Germany. By 1916 potash was transported via the Trona Railway to farmers, who needed fertilizer, to feed the nation during World War I.
Three Elephant Route
The name Three Elephant Route was created, because many of the railroad's employees were British and did not understand why the company should hold on to its heritage of 20 mule teams. As the story goes, they felt that three elephants could have done the job as well, if not better, than a herd of mules. The slogan was used as a brand and logo, which adorned Trona Railway equipment into the late 1940s.
Diesel locomotives
In April 1949 the Trona Railway purchased two new Baldwin DT-6-6-2000 locomotives (numbered 50 and 51) to replace the three steam locomotives that were operating at the time. These weighed 180 tons each and had 2000 hp motors. These locomotives were unique in that they had center cabs, not the traditional cabs in the front. Locomotive No 52 was a smaller Baldwin AS 616 that only developed 1,600 hp. Eventually, two more AS 616 locomotives were added to the fleet to bring the total to five. A small diesel-electric locomotive called Dinky was used for switching in the rail yards. A crew car was used for safety inspections of the rail track and to bring employees to the site of track maintenance.
The Baldwins were sold in late 1992, replaced with six leased EMD SD45-2's, all painted in red and silver similar to the earlier Baldwins. These in turn were replaced in 2004 by the current fleet (as of February 2021) of seven EMD SD40-2 and EMD SD40T-2 locomotives, all of which remain in the faded color schemes of their former owners, Union Pacific and Southern Pacific. At least one EMD SW1200 switcher is also on the roster.
Operations
The main line runs from Trona to the interchange with the Union Pacific's Lone Pine Subdivision at Searles, a distance of . It has a maximum grade of 1.9% and has gentle curves, which permit a maximum speed of .
The railroad handles 18,000 cars annually (1996 estimate). Commodities hauled include:
Sulfuric acid
Soda ash
Potash
Salt cake
Borax
Coal
Minerals
Material for the U.S. Naval Air Weapons Station China Lake
See also
United States Potash Railroad: a potash railroad in New Mexico
References
Bibliography
California railroads
Mining in California
Mining railways in the United States
Mojave Desert
Searles Valley
Transportation in San Bernardino County, California
Railway companies established in 1914
1914 establishments in California
Potash | Trona Railway | Chemistry | 1,122 |
73,742,916 | https://en.wikipedia.org/wiki/Luisa%20Verdoliva | Annalisa (Luisa) Verdoliva (born 1972) is an Italian engineer whose research concerns image processing and digital forensics of multimedia data, including the detection of deepfakes and other AI-generated imagery. She is a professor in the Department of Industrial Engineering at the University of Naples Federico II, where she directs the Multimedia Forensics Lab.
Verdoliva was born in 1972, and earned a laurea in telecommunications engineering from the University of Naples Federico II. She chaired the IEEE Information Forensics and Security Technical Committee from 2021 to 2022, and was named to a government task force on fake news in 2020.
She was named an IEEE Fellow, in the 2021 class of fellows, "for contribution to multimedia forensics".
References
External links
Home page
1972 births
Living people
Italian engineers
Italian women engineers
Telecommunications engineers
University of Naples Federico II alumni
Academic staff of the University of Naples Federico II
Fellows of the IEEE | Luisa Verdoliva | Engineering | 188 |
52,584,751 | https://en.wikipedia.org/wiki/Candid%20%28app%29 | Candid was a mobile app for anonymous discussions. It used machine learning to create personalized newsfeeds of opinions and real conversations, and also for moderation and filtering. Users posted under pseudonyms such as "HyperMantis", "SincereGiraffe", "GroundedTurtle" and "ExuberantRaptor", that are unique for each thread.
Founder and CEO Bindu Reddy said that she needed "a place to express myself and engage in discussions where ideas can be debated on their own merits instead of being used to attack me as a person", which Candid tried to solve by redirecting off-topic comments to their appropriate groups, removing spam and flagging negative posts. They used natural language processing to identify hate speech, slander and threats, and removed them accordingly with human intervention. Candid software analyzed topics and tried to flag rumors and lies as such. Users could flag problematic posts and a team of ten contractors would review them individually. With time the system analyzed a user's interactions and give them labels, such as socializer, explorer, positive, influencer, hater, gossip, etc.
In June 2017, Candid announced that it would be shut down because its parent company, Post Intelligence, was being acquired. The app was forecast to close on June 23, 2017, but didn't actually close until June 25, 2017.
Notes
References
Mobile applications
IOS software
Anonymous social media | Candid (app) | Technology | 295 |
36,088,304 | https://en.wikipedia.org/wiki/Too%20Big%20to%20Know | Too Big to Know: Rethinking Knowledge Now That the Facts Aren't the Facts, Experts Are Everywhere, and the Smartest Person in the Room Is the Room is a non-fiction book by the American technology writer David Weinberger published in 2012 by Basic Books.
Overview
It describes the World Wide Web-enabled shift in the production, transmission, reception, and storage of knowledge in the early 21st century. Weinberger discusses topics such as expertise, echo chambers, open government, the WELL, Debian, the U.S. Army's Center for the Advancement of Leader Development and Organizational Learning; and the writing of Charles Darwin (On the Origin of Species) and Nicholas G. Carr ("Is Google Making Us Stoopid?"). He argues that "networked knowledge brings us closer to the truth about knowledge."
See also
Knowledge ecosystem
References
Further reading
External links
Official website
Basic Books webpage for Too Big to Know
Books about the Internet
Networks
2012 non-fiction books
Books about books
American non-fiction books
Web 2.0
Works about information
Basic Books books | Too Big to Know | Technology | 221 |
4,044,299 | https://en.wikipedia.org/wiki/Spin%E2%80%93charge%20separation | In condensed matter physics, spin–charge separation is an unusual behavior of electrons in some materials in which they 'split' into three independent particles, the spinon, the orbiton and the holon (or chargon). The electron can always be theoretically considered as a bound state of the three, with the spinon carrying the spin of the electron, the orbiton carrying the orbital degree of freedom and the chargon carrying the charge, but in certain conditions they can behave as independent quasiparticles.
The theory of spin–charge separation originates with the work of Sin-Itiro Tomonaga who developed an approximate method for treating one-dimensional interacting quantum systems in 1950. This was then developed by Joaquin Mazdak Luttinger in 1963 with an exactly solvable model which demonstrated spin–charge separation. In 1981 F. Duncan M. Haldane generalized Luttinger's model to the Tomonaga–Luttinger liquid concept whereby the physics of Luttinger's model was shown theoretically to be a general feature of all one-dimensional metallic systems. Although Haldane treated spinless fermions, the extension to spin-½ fermions and associated spin–charge separation was so clear that the promised follow-up paper did not appear.
Spin–charge separation is one of the most unusual manifestations of the concept of quasiparticles. This property is counterintuitive, because neither the spinon, with zero charge and spin half, nor the chargon, with charge minus one and zero spin, can be constructed as combinations of the electrons, holes, phonons and photons that are the constituents of the system. It is an example of fractionalization, the phenomenon in which the quantum numbers of the quasiparticles are not multiples of those of the elementary particles, but fractions.
The same theoretical ideas have been applied in the framework of ultracold atoms. In a two-component Bose gas in 1D, strong interactions can produce a maximal form of spin–charge separation.
Observation
Building on physicist F. Duncan M. Haldane's 1981 theory, experts from the Universities of Cambridge and Birmingham proved experimentally in 2009 that a mass of electrons artificially confined in a small space together will split into spinons and holons due to the intensity of their mutual repulsion (from having the same charge). A team of researchers working at the Advanced Light Source (ALS) of the U.S. Department of Energy's Lawrence Berkeley National Laboratory observed the peak spectral structures of spin–charge separation three years prior.
References
External links
Observation of Spin-Charge Separation in One-Dimensional SrCuO2
Distinct spinon and holon dispersions in photoemission spectral functions from one-dimensional SrCuO2 : Abstract
Quasiparticles
Condensed matter physics | Spin–charge separation | Physics,Chemistry,Materials_science,Engineering | 577 |
56,296,491 | https://en.wikipedia.org/wiki/Silkhenge | Silkhenge structures are a means of spider reproduction used by one or more currently-unknown species of spider. It typically consists of a central "spire" constructed of spider silk, containing one to two eggs, surrounded by a sort of fence of silk in a circle.
Discovery
In August 2013, Georgia Tech student Troy Alexander was visiting Tambopata National Reserve in Peru. He found, under a tarpaulin, a tiny bit of silk in a circular pattern approximately one inch in diameter. Upon further investigation of the area, Alexander found three additional similar structures. He posted a picture on Reddit asking for help identifying it. No information was forthcoming, as this turned out to be a completely unknown phenomenon. His discovery acquired the name "silkhenge" because of its similarity to Stonehenge.
At the end of that year, an eight-day expedition led by Phil Torres found dozens more examples of this phenomenon, generally on the trunks of bamboo and cecropia trees. Spiderlings hatching from the structures were documented, but like many baby arthropods they lacked the features typically used to identify adults, and none lived to adulthood. DNA tests were also inconclusive, so the species creating these structures remained unidentified. A video was posted on YouTube of spiderlings hatching.
One hypothesized purpose of the fence is that it serves to trap mites and other small arthropods known to share the same habitat. This could, in turn, secure a food source that would be easily accessible to the spiderlings upon hatching. It has also been proposed that it protects the eggs and spiderlings from possible predators such as ants.
References
Spiders
Silk
Invertebrates of Peru
Shelters built or used by animals
Eggs
2013 in biology | Silkhenge | Biology | 354 |
17,862,638 | https://en.wikipedia.org/wiki/Metribolone | Metribolone (developmental code R1881, also known as methyltrienolone) is a synthetic and orally active anabolic–androgenic steroid (AAS) and a 17α-alkylated nandrolone (19-nortestosterone) derivative which was never marketed for medical use but has been widely used in scientific research as a hot ligand in androgen receptor (AR) ligand binding assays (LBAs) and as a photoaffinity label for the AR. More precisely, metribolone is the 17α-methylated derivative of trenbolone. It was investigated briefly for the treatment of advanced breast cancer in women in the late 1960s and early 1970s, but was found to produce signs of severe hepatotoxicity at very low dosages, and its development was subsequently discontinued.
Medical uses
Metribolone was never approved for medical use, a situation unlikely to change given its liver toxicity even at low doses. It was studied for the potential treatment of advanced breast cancer in women but development was abandoned.
Side effects
Side effects of metribolone include virilization and hepatotoxicity among others.
Pharmacology
Pharmacodynamics
Metribolone is an AAS, or an agonist of the AR, with both anabolic and androgenic activity. It is one of the most potent AAS to have ever been synthesized, with 120 to 300 times the oral anabolic potency and 60 to 70 times the androgenic potency of the reference AAS methyltestosterone in castrated male rats, although the same level of potency has not been observed in studies in humans. In addition to the AR, metribolone has high affinity for the progesterone receptor (PR), and binds to the glucocorticoid receptor (GR) as well. The drug was also identified in 2007 as a potent antimineralocorticoid, with similar affinity for the mineralocorticoid receptor as aldosterone and spironolactone. In addition, metribolone was identified in 2010 as a potent inhibitor of 3β-hydroxysteroid dehydrogenase (3β-HSD) 1 and 2 (IC50 = 0.02 and 0.16 μM, respectively). On the basis of this finding, it has been said that metribolone should be used very cautiously in scientific research, taking into account 3β-HSD inhibition to avoid erroneous interpretation.
Metribolone has a high potential for hepatotoxicity, similarly to other 17α-alkylated AAS. However, the hepatotoxic potential of metribolone appears to be exceptionally high, likely in relation to its very high potency and metabolic stability; in a study of treatment with the drug for advanced breast cancer, severe hepatic dysfunction was observed at very low dosages.
Pharmacokinetics
Metribolone has very low affinity for human serum sex hormone-binding globulin (SHBG), less than 5% of that of testosterone and less than 1% of that of dihydrotestosterone (DHT).
Chemistry
Metribolone, also known as 17α-methyltrenbolone, as well as 17α-methyl-δ9,11-19-nortestosterone or 17α-methylestra-4,9,11-trien-17β-ol-3-one, is a synthetic estrane steroid and a 17α-alkylated derivative of nandrolone (19-nortestosterone). It is the C17α methylated derivative of trenbolone (δ9,11-19-nortestosterone) and the C9- and C11-dehydrogenated (δ9,11) analogue of normethandrone (17α-methyl-19-nortestosterone). Other close relatives and derivatives of metribolone include mibolerone (7α,17α-dimethyl-19-nortestosterone) and dimethyltrienolone (RU-2420; 7α,17α-dimethyl-δ9,11-19-nortestosterone). In addition to AAS, trimethyltrienolone (R2956; 2α,2β,17α-trimethyl-δ9,11-19-nortestosterone), a highly potent antiandrogen, has been derived from metribolone.
History
Metribolone was first described in the literature in 1965. It was studied clinically in the late 1960s and early 1970s, most notably in the treatment of advanced breast cancer. The drug was found to be effective and showed weak androgenicity, but also produced severe signs of hepatotoxicity, and was ultimately never marketed. By the mid-1970s, metribolone was becoming an accepted standard as a ligand and agonist of the AR in scientific research. It remains in wide use for this purpose today. Aside from scientific research, metribolone has also been encountered as an AAS in non-medical contexts, for instance in doping in sports and bodybuilding.
Society and culture
Generic names
Metribolone is the generic name of metribolone and its . It is also known by the name methyltrienolone and its developmental code names R1881, R-1881, RU-1881, and RU1881, and is very commonly referred to by these other names rather than as metribolone in the scientific literature.
Doping in sports
Prior to the 2008 Beijing Olympic Games, 11 members of the Greek national weightlifting team and 4 Greek track and field athletes tested positive for metribolone.
References
External links
Methyltrienolone - William Llewellyn's Anabolic.org
3β-Hydroxysteroid dehydrogenase inhibitors
Tertiary alcohols
Anabolic–androgenic steroids
Antimineralocorticoids
Estranes
Glucocorticoids
Hepatotoxins
Enones
Progestogens
Abandoned drugs | Metribolone | Chemistry | 1,286 |
37,255,406 | https://en.wikipedia.org/wiki/61%20Leonis | 61 Leonis is a possible binary star system in the zodiac constellation of Leo. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.73. The star is moving closer to the Sun with a heliocentric radial velocity of −12.7 km/s. It is located roughly 580 light-years from the Sun, as determined from its annual parallax shift of .
This is an evolved red giant star with a stellar classification of M0 III that Eggen (1992) listed as being on the asymptotic giant branch (AGB). It is a marginal barium star, showing an enhanced abundance of s-process elements in its outer atmosphere. This material may have been acquired during a previous mass transfer from a now white dwarf companion, or self-enriched by a dredge-up during the AGB process. The measured angular diameter after correctly for limb darkening is , which, at the estimated distance of this system yields a physical size of about 74.5 times the radius of the Sun.
61 Leonis is a suspected variable star with apparent magnitude changing between 4.69 and 4.79. The variability was reported in a 1966 photometric survey, but has not been confirmed by more recent photometry.
References
M-type giants
Suspected variables
Barium stars
Leo (constellation)
Leo, p2
Durchmusterung objects
Leonis, 61
095578
053907
4299 | 61 Leonis | Astronomy | 295 |
25,061,776 | https://en.wikipedia.org/wiki/Simon%E2%80%93Glatzel%20equation | The Simon–Glatzel equation is an empirical correlation describing the pressure dependence of the melting temperature of a solid. The pressure dependence of the melting temperature is small for small pressure changes because the volume change during fusion or melting is rather small. However, at very high pressures higher melting temperatures are generally observed as the liquid usually occupies a larger volume than the solid making melting more thermodynamically unfavorable at elevated pressure. If the liquid has a smaller volume than the solid (as for ice and liquid water) a higher pressure leads to a lower melting point.
The equation and its variations
and are normally the temperature and the pressure of the triple point, but the normal melting temperature at atmospheric pressure are also commonly used as reference point because the normal melting point is much more easily accessible. Typically is then set to 0. and are component-specific parameters.
The Simon–Glatzel equation can be viewed as a combination of the Murnaghan equation of state and the Lindemann law, and an alternative form was proposed by J. J. Gilvarry (1956):
where is general at , is pressure derivative at , is Grüneisen ratio, and is the coefficient in Morse potential.
Example parameters
For methanol the following parameters can be obtained:
The reference temperature has been Tref = 174.61 K and the reference pressure Pref has been set to 0 kPa.
Methanol is a component where the Simon–Glatzel works well in the given validity range.
Extensions and generalizations
The Simon–Glatzel equation is a monotonically increasing function. It can only describe the melting curves that rise indefinitely with increasing pressure. It may fail to describe the melting curves with a negative pressure dependence or local maximums. A damping term that asymptotically slopes down under pressure, (c is another component-specific parameter), is introduced by Vladimir V. Kechin to extend the Simon–Glatzel equation so that all melting curves, rising, falling, and flattening, as well as curves with a maximum, can be described by a unified equation:
where is the Simon–Glatzel equation (rising) and is the damping term (falling or flattening).
The unified equation may be rewritten as:
This form predicts that all solids have a maximum melting temperature at a positive or (fictitious) negative pressure.
References
Phase transitions
Equations
Thermodynamics | Simon–Glatzel equation | Physics,Chemistry,Mathematics | 496 |
5,507,641 | https://en.wikipedia.org/wiki/Context-sensitive%20half-life | Context-sensitive half-life or context sensitive half-time is defined as the time taken for blood plasma concentration of a drug to decline by one half after an infusion designed to maintain a steady state (i.e. a constant plasma concentration) has been stopped. The "context" is the duration of infusion.
When a drug which has a multicompartmental pharmacokinetic model is given by intravenous infusion it initially will distribute to the central compartment and then move out of this compartment into one or two peripheral compartments. Once this infusion is discontinued, drug continues to move into the peripheral compartments until an equilibrium is reached. At this time, the only way drug may leave plasma is by metabolism or excretion. As the plasma concentration falls, the concentration gradient of drug reverses and drug moves from peripheral compartments back into plasma, maintaining the plasma concentration of the drug, often prolonging the pharmacological effect. If an infusion has reached steady state then the context-sensitive half-life is equal to the terminal plasma half-life of the drug. Otherwise it will be shorter than the terminal elimination half-life.
Remifentanil is relatively context insensitive whilst fentanyl and thiopentone are examples of drugs which have significant context-sensitive changes in their half-life.
The Context-Sensitive Half-Time describes the time required for the plasma drug concentration to decline by 50% after terminating an infusion of a particular duration.
Definition
It is the time required for drug plasma concentration to decrease by 50% after stopping administration. The drug is administered continuously.
Pharmacokinetics
Many drugs follow the multi-compartment model. In other words, a drug may have a preference for a particular body compartment which will result in the majority of that drug to ultimately settle in that particular compartment.
For highly polar drugs very little will be in the tissues of the body
For highly lipophilic drugs majority of drug will be located in body tissues
Initially, because the drug is given intravenously, the drug will distribute to the central compartment (i.e. circulation system). The drug (e.g. lipophilic drug) will move out of the central compartment and move into the peripheral compartments
The movement from one compartment to another is influenced by passive diffusion (Moves from an area of high concentration to one with low concentration)
A drug like fentanyl is very fat soluble. Initial doses ‘wear off’ relatively quickly because the drug redistributes to adipose tissue. However, if the infusion is ongoing then the peripheral compartment (body tissue) will have a large store of fentanyl
The duration of infusion determines whether or not steady state was reached
Once a drug enters the body, elimination and distribution begins. Initially the drug present in central compartment (i.e. circulation system) is being distributed into the tissues, and being eliminated
At steady state, the concentration of free drug in the central compartment (i.e. circulation system) is equal to the concentration of free drug in the peripheral compartment (i.e. body tissues)
If steady state is reached, context-sensitive half-life is equal to elimination half-life
Only free drug that is in the plasma is metabolised
Metabolism results in the concentration of free drug in the peripheral compartment to decrease
Due to passive diffusion, free drug will leave the peripheral compartment (i.e. tissues) and enter the central compartment, replenishing any drug that was metabolised from the plasma
If steady state is not reached, context-sensitive half-life is shorter than elimination half-life
Only free drug that is in the plasma is metabolised
Overall the entire body has less lipophilic drug. The infusion was stopped earlier. Not as much drug was able to enter the peripheral compartment.
Because steady state is not reached, the peripheral compartment (i.e. tissues) has less free drug than the central compartment
The drug continues to move into the peripheral compartment until equilibrium is reached. Remember the drug moves due to passive diffusion. It moves into the peripheral compartment because it has less free drug
Once equilibrium is reached, the only other way the drug is able to leave the plasma is by elimination. This causes the free drug concentration in the central compartment to fall
As the plasma concentration falls, the concentration gradient of drug reverses and drug moves from peripheral compartment (i.e. tissues) back into plasma, maintaining the plasma concentration of the drug
Remifentanil is relatively context insensitive. Fentanyl and thiopental are examples of drugs which have significant context-sensitive changes in their half-life.
References
Pharmacokinetics | Context-sensitive half-life | Chemistry | 956 |
1,343,120 | https://en.wikipedia.org/wiki/Tokyo%20Designers%20Block | Tokyo Designers Block (TDB) is one of Tokyo's main recurring design events. It is a 5-day exhibition showcasing hundreds of international and domestic designers of all backgrounds. Works are displayed all through Tokyo's fashionable districts, in shop windows, exhibition spaces and galleries.
TDB is the brainchild of Teruo Kurosaki, president of Aoyama design shop Idée, who got the idea following a visit to London's designersblock. "TDB is not a design event nor a trade show of product designs; we are willing to make fun of design and try the best how design can do to the society in Tokyo."
History
2000 (12-15 October) "Form follows your mind"
2001 (10-14 October) "Design makes cities"
2002 (10-14 October) "Design has no boundaries"
2003 (9-13 October) "Anything goes design flows 2003"
2004 (7-11 October) "1968 revolutions"
2006 (31 October-5 November) "100% design tokyo"
External links
Designersblock
Design institutions
Events in Tokyo | Tokyo Designers Block | Engineering | 220 |
24,920,134 | https://en.wikipedia.org/wiki/Rank%20factorization | In mathematics, given a field , non-negative integers , and a matrix , a rank decomposition or rank factorization of is a factorization of of the form , where and , where is the rank of .
Existence
Every finite-dimensional matrix has a rank decomposition: Let be an matrix whose column rank is . Therefore, there are linearly independent columns in ; equivalently, the dimension of the column space of is . Let be any basis for the column space of and place them as column vectors to form the matrix . Therefore, every column vector of is a linear combination of the columns of . To be precise, if is an matrix with as the -th column, then
where 's are the scalar coefficients of in terms of the basis . This implies that , where is the -th element of .
Non-uniqueness
If is a rank factorization, taking and
gives another rank factorization for any invertible matrix of compatible dimensions.
Conversely, if are two rank factorizations of , then there exists an invertible matrix such that and .
Construction
Rank factorization from reduced row echelon forms
In practice, we can construct one specific rank factorization as follows: we can compute , the reduced row echelon form of . Then is obtained by removing from all non-pivot columns (which can be determined by looking for columns in which do not contain a pivot), and is obtained by eliminating any all-zero rows of .
Note: For a full-rank square matrix (i.e. when ), this procedure will yield the trivial result and (the identity matrix).
Example
Consider the matrix
is in reduced echelon form.
Then is obtained by removing the third column of , the only one which is not a pivot column, and by getting rid of the last row of zeroes from , so
It is straightforward to check that
Proof
Let be an permutation matrix such that in block partitioned form, where the columns of are the pivot columns of . Every column of is a linear combination of the columns of , so there is a matrix such that , where the columns of contain the coefficients of each of those linear combinations. So , being the identity matrix. We will show now that .
Transforming into its reduced row echelon form amounts to left-multiplying by a matrix which is a product of elementary matrices, so , where . We then can write , which allows us to identify , i.e. the nonzero rows of the reduced echelon form, with the same permutation on the columns as we did for . We thus have , and since is invertible this implies , and the proof is complete.
Singular value decomposition
If then one can also construct a full-rank factorization of via a singular value decomposition
Since is a full-column-rank matrix and is a full-row-rank matrix, we can take and .
Consequences
rank(A) = rank(AT)
An immediate consequence of rank factorization is that the rank of is equal to the rank of its transpose . Since the columns of are the rows of , the column rank of equals its row rank.
Proof: To see why this is true, let us first define rank to mean column rank. Since , it follows that . From the definition of matrix multiplication, this means that each column of is a linear combination of the columns of . Therefore, the column space of is contained within the column space of and, hence, .
Now, is , so there are columns in and, hence, . This proves that .
Now apply the result to to obtain the reverse inequality: since , we can write . This proves .
We have, therefore, proved and , so .
Notes
References
Matrix decompositions
Linear algebra | Rank factorization | Mathematics | 760 |
13,806,294 | https://en.wikipedia.org/wiki/Runaway%20train | A runaway train is a type of railroad incident in which unattended rolling stock is accidentally allowed to roll onto the main line, a moving train loses enough braking power to be unable to stop in safety, or a train operates at unsafe speeds due to loss of operator control. If the uncontrolled rolling stock derails or hits another train, it will result in a train wreck.
A deadman's control, if the brakes are working, can prevent unattended rolling stock from moving.
A railway air brake can fail if valves on the pipe between each wagon are accidentally closed; the 1953 Pennsylvania Railroad train wreck and the 1988 Gare de Lyon train accident were results of a valve accidentally closed by the crew, reducing braking power.
A parked train or cut off cars may also run away if not properly tied down with a sufficient number of hand brakes.
Incidents
Accidents and incidents involving defective or improperly-set railway brakes include:
See also
Dark territory
Positive train control
Railroad Safety Appliance Act
:Category:Runaway train disasters
References
*
Railway accidents and incidents | Runaway train | Technology | 216 |
33,815,178 | https://en.wikipedia.org/wiki/Metadata%20repository | A metadata repository is a database created to store metadata. Metadata is information about the structures that contain the actual data. Metadata is often said to be "data about data", but this is misleading. Data profiles are an example of actual "data about data". Metadata adds one layer of abstraction to this definition– it is data about the structures that contain data. Metadata may describe the structure of any data, of any subject, stored in any format.
A well-designed metadata repository typically contains data far beyond simple definitions of the various data structures. Typical repositories store dozens to hundreds of separate pieces of information about each data structure.
Comparing the metadata of a couple data items - one digital and one physical - clarify what metadata is:
First, digital: For data stored in a database one may have a table called "Patient" with many columns, each containing data which describes a different attribute of each patient. One of these columns may be named "Patient_Last_Name". What is some of the metadata about the column that contains the actual surnames of patients in the database? We have already used two items: the name of the column that contains the data (Patient_Last_Name) and the name of the table that contains the column (Patient). Other metadata might include the maximum length of last name that may be entered, whether or not last name is required (can we have a patient without Patient_Last_Name?), and whether the database converts any surnames entered in lower case to upper case. Metadata of a security nature may show the restrictions which limit who may view these names.
Second, physical: For data stored in a brick and mortar library, one have many volumes and may have various media, including books. Metadata about books would include ISBN, Binding_Type, Page_Count, Author, etc. Within Binding_Type, metadata would include possible bindings, material, etc.
This contextual information of business data include meaning and content, policies that govern, technical attributes, specifications that transform, and programs that manipulate.
Definition
The metadata repository is responsible for physically storing and cataloging metadata. Data in a metadata repository should be generic, integrated, current, and historical:
Generic Meta model should store the metadata by generic terms instead of storing it by an applications-specific defined way, so that if your data base standard changes from one product to another the physical meta model of the metadata repository would not need to change.
Integration of the metadata repository allows all business areas' metadata to be in an integrated fashion: Covering all domains and subject areas of the organization.
current and historicalThe metadata repository should have accessible current and historical metadata. Metadata repositories used to be referred to as a data dictionary.
With the transition of needs for the metadata usage for business intelligence has increased so is the scope of the metadata repository increased. Earlier data dictionaries are the closest place to interact technology with business. Data dictionaries are the universe of metadata repository in the initial stages but as the scope increased Business glossary and their tags to variety of status flags emerged in the business side while consumption of the technology metadata, their lineage and linkages made the repository, the source for valuable reports to bring business and technology together and helped data management decisions easier as well as assess the cost of the changes.
Metadata repository explores the enterprise wide data governance, data quality and master data management (includes master data and reference data) and integrates this wealth of information with integrated metadata across the organization to provide decision support system for data structures, even though it only reflects the structures consumed from various systems.
Repository vs. registry
Repository has additional functionalities compared with registry. Metadata repository not only stores metadata like Metadata registry but also adds relationships with related metadata types. Metadata when related in a flow from its point of entry into organization up to the deliverables is considered as the lineage of that data point. Metadata when related across other related metadata types is called linkages. By providing the relationships to all the metadata points across the organization and maintaining its integrity with an architecture to handle the changes, metadata repository provides the basic material for understanding the complete data flow and their definitions and their impact. Also the important feature is to maintain the version control though this statement for contrasting is open for discussion. These definitions are still evolving, so the accuracy of the definitions needs refinement.
The purpose of registry is to define the metadata element and maintained across the organization. And data models and other data management teams refer to the registry for any changes to follow. While Metadata repository sources metadata from various metadata systems in the organizations and reflects what is in the upstream. Repository never acts as an upstream while registry is used as an upstream for metadata changes.
Reason for use
Metadata repository enables all the structure of the organizations data containers to one integrated place. This opens plethora of resourceful information for making calculated business decisions. This tool uses one generic form of data model to integrate all the models thus brings all the applications and programs of the organization into one format. And on top of it applying the business definitions and business processes brings the business and technology closer that will help organizations make reliable roadmaps with definite goals. With one stop information, business will have more control on the changes, and can do impact analysis of the tool. Usually business spends much time and money to make decisions based on discovery and research on impacts to make changes or to add new data structures or remove structures in data management of the organization. With a structured and well maintained repository, moving the product from ideation to delivery takes the least amount of time (considering other variables are constant).
To sum it up:
Integration of the metadata across the organization
Build relationship between various metadata types
Build relationship between various disparate systems
Define business golden copy of definitions
Version control of the changes at structure level
Interaction with Reference data
Link view to master data
Automatic synchronization with various authorized metadata source systems
More control to business decisions
Validate the structures by overlapping the models
Discovering discrepancies, gaps, lineage, metrics at data structure level
Each database management system (DBMS) and database tools have their own language for the metadata components within. Database applications already have their own repositories or registries that are expected to provide all of the necessary functionality to access the data stored within. Vendors do not want other companies to be capable of easily migrating data away from their products and into competitors products, so they are proprietary with the way they handle metadata. CASE tools, DBMS dictionaries, ETL tools, data cleansing tools, OLAP tools, and data mining tools all handle and store metadata differently. Only a metadata repository can be designed to store the metadata components from all of these tools.
Design
Metadata repositories should store metadata in four classifications: ownership, descriptive characteristics, rules and policies, and physical characteristics. Ownership, showing the data owner and the application owner. The descriptive characteristics, define the names, types and lengths, and definitions describing business data or business processes. Rules and policies, will define security, data cleanliness, timelines for data, and relationships. Physical characteristics define the origin or source, and physical location. Like building a logical data model for creating a database, a logical meta model can help identify the metadata requirements for business data. The metadata repository will be centralized, decentralized, or distributed. A centralized design means that there is one database for the metadata repository that stores metadata for all applications business wide. A centralized metadata repository has the same advantages and disadvantages of a centralized database. Easier to manage because all the data is in one database, but the disadvantage is that bottlenecks may occur.
A decentralized metadata repository stores metadata in multiple databases, either separated by location and or departments of the business. This makes management of the repository more involved than a centralized metadata repository, but the advantage is that the metadata can be broken down into individual departments.
A distributed metadata repository uses a decentralized method, but unlike a decentralized metadata repository the metadata remains in its original application. An XML gateway is created that acts as a directory for accessing the metadata within each different application. The advantages and disadvantages for a distributed metadata repository mirror that of a distributed database.
Design of information model should include various layers of metadata types to be overlapped to create an integrated view of the data. Various metadata types should be stitched with related metadata elements in a top down model linking to business glossary.
Layers of Metadata:
Business Glossary: contains recursive relationship to Business terms.
Business tags: Contains various affiliation to that term or terms.
Data Dictionary: contains information from data model tools for the definition of metadata elements and their technical definitions provided by data or enterprise architecture.
Conceptual data models:
Logical data models
Physical data models
Databases
validation rules and data quality rules
ETL, business rules and their relationship to attributes and entities
Reports
Source to target mapping artifacts (relationships)
Reporting requirements (relationships)
business processes and their relationship to technology
people hierarchy and their relationship
owner relationship
Entity-Relationship/Object-Oriented
Metadata repositories can be designed as either an Entity-relationship model, or an Object-oriented design.
See also
References
Data modeling
Databases
Metadata
Metadata registry | Metadata repository | Technology,Engineering | 1,861 |
21,235,839 | https://en.wikipedia.org/wiki/Cemented%20carbide | Cemented carbides are a class of hard materials used extensively for cutting tools, as well as in other industrial applications. It consists of fine particles of carbide cemented into a composite by a binder metal. Cemented carbides commonly use tungsten carbide (WC), titanium carbide (TiC), or tantalum carbide (TaC) as the aggregate. Mentions of "carbide" or "tungsten carbide" in industrial contexts usually refer to these cemented composites.
Most of the time, carbide cutters will leave a better surface finish on a part and allow for faster machining than high-speed steel or other tool steels. Carbide tools can withstand higher temperatures at the cutter-workpiece interface than standard high-speed steel tools (which is a principal reason enabling the faster machining). Carbide is usually superior for the cutting of tough materials such as carbon steel or stainless steel, as well as in situations where other cutting tools would wear away faster, such as high-quantity production runs. In situations where carbide tooling is not required, high-speed steel is preferred for its lower cost.
Construction
Cemented carbides are metal matrix composites where carbide particles act as the aggregate and a metallic binder serves as the matrix (analogous to concrete, where a gravel aggregate is suspended in a cement matrix). The structure of cemented carbide is conceptually similar to that of a grinding wheel, but the abrasive particles are much smaller; macroscopically, the material of a carbide cutter appears homogeneous.
The process of combining the carbide particles with the binder is referred to as sintering or hot isostatic pressing (HIP). During this process, the material is heated until the binder enters a liquid phase while the carbide grains (which have a much higher melting point) remain solid. At this elevated temperature and pressure, the carbide grains rearrange themselves and compact together, forming a porous matrix. The ductility of the metal binder serves to offset the brittleness of the carbide ceramic, resulting in the composite's high overall toughness and durability. By controlling various parameters, including grain size, cobalt content, dotation (e.g., alloy carbides) and carbon content, a carbide manufacturer can tailor the carbide's performance to specific applications.
The first cemented carbide developed was tungsten carbide (introduced in 1927) which uses tungsten carbide particles held together by a cobalt metal binder. Since then, other cemented carbides have been developed, such as titanium carbide, which is better suited for cutting steel, and tantalum carbide, which is tougher than tungsten carbide.
Physical properties
The coefficient of thermal expansion of cemented tungsten carbide is found to vary with the amount of cobalt used as a metal binder. For 5.9% cobalt samples, a coefficient of 4.4 μm/m·K was measured, whereas 13% cobalt samples have a coefficient of around 5.0 μm/m·K. Both values are only valid from to due to non-linearity in the thermal expansion process.
Applications
Inserts for metal cutting
Carbide is more expensive per unit than other typical tool materials, and it is more brittle, making it susceptible to chipping and breaking. To offset these problems, the carbide cutting tip itself is often in the form of a small insert for a larger tipped tool whose shank is made of another material, usually carbon tool steel. This gives the benefit of using carbide at the cutting interface without the high cost and brittleness of making the entire tool out of carbide. Most modern face mills use carbide inserts, as well as many lathe tools and endmills. In recent decades, though, solid-carbide endmills have also become more commonly used, wherever the application's characteristics make the pros (such as shorter cycle times) outweigh the cons (mentioned above). As well, modern turning (lathe) tooling may use a carbide insert on a carbide tool such as a boring bar, which are more rigid than steel insert holders and therefor less prone to vibration, which is of particular importance with boring or threading bars that may need to reach into a part to a depth many times the tool diameter.
Insert coatings
To increase the life of carbide tools, they are sometimes coated. Five such coatings are TiN (titanium nitride), TiC (titanium carbide), Ti(C)N (titanium carbide-nitride), TiAlN (titanium aluminium nitride) and AlTiN (aluminium titanium nitride). (Newer coatings, known as DLC (diamond-like carbon) are beginning to surface, enabling the cutting power of diamond without the unwanted chemical reaction between real diamond and iron.) Most coatings generally increase a tool's hardness and/or lubricity. A coating allows the cutting edge of a tool to cleanly pass through the material without having the material gall (stick) to it. The coating also helps to decrease the temperature associated with the cutting process and increase the life of the tool. The coating is usually deposited via thermal chemical vapor deposition (CVD) and, for certain applications, with the mechanical physical vapor deposition (PVD) method. However, if the deposition is performed at too high temperature, an eta phase of a Co6W6C tertiary carbide forms at the interface between the carbide and the cobalt phase, which may lead to adhesion failure of the coating.
Inserts for mining tools
Mining and tunneling cutting tools are most often fitted with cemented carbide tips, the so-called "button bits". Artificial diamond can replace the cemented carbide buttons only when conditions are ideal, but as rock drilling is a tough job cemented carbide button bits remain the most used type throughout the world.
Rolls for hot-roll and cold-roll applications
Since the mid-1960s, steel mills around the world have applied cemented carbide to the rolls of their rolling mills for both hot and cold rolling of tubes, bars, and flats.
Other industrial applications
This category contains a countless number of applications, but can be split into three main areas:
Engineered components
Wear parts
Tools and tool blanks
Some key areas where cemented carbide components are used:
Automotive components
Canning tools for deep drawing of two-piece cans
Rotary cutters for high-speed cutting of artificial fibres
Metal forming tools for wire drawing and stamping applications, such as drawing dies.
Rings and bushings typically for bump and seal applications
Woodworking, e.g., for sawing and planing applications
Pump pistons for high-performance pumps (e.g., in nuclear installations)
Nozzles, e.g., high-performance nozzles for oil drilling applications
Roof and tail tools and components for high wear resistance
Balls for ball bearings and ballpoint pens
Non-industrial uses
Jewellery
Tungsten carbide has become a popular material in the bridal jewellery industry, due to its extreme hardness and high resistance to scratching. Given its brittleness, it is prone to chip, crack, or shatter in jewellery applications. Once fractured, it cannot be repaired.
History
The initial development of cemented and sintered carbides occurred in Germany in the 1920s. ThyssenKrupp says [in historical present tense], "Sintered tungsten carbide was developed by the 'Osram study society for electrical lighting' to replace diamonds as a material for machining metal. Not having the equipment to exploit this material on an industrial scale, Osram sells the license to Krupp at the end of 1925. In 1926 Krupp brings sintered carbide onto the market under the name WIDIA (acronym for = like diamond)." Machinery's Handbook gives the date of carbide tools' commercial introduction as 1927. Burghardt and Axelrod give the date of their commercial introduction in the United States as 1928. Subsequent development occurred in various countries.
Although the marketing pitch was slightly hyperbolic (carbides being not entirely equal to diamond), carbide tooling offered an improvement in cutting speeds and feeds so remarkable that, like high-speed steel had done two decades earlier, it forced machine tool designers to rethink every aspect of existing designs, with an eye toward yet more rigidity and yet better spindle bearings.
During World War II there was a tungsten shortage in Germany. It was found that tungsten in carbide cuts metal more efficiently than tungsten in high-speed steel, so to economise on the use of tungsten, carbides were used for metal cutting as much as possible.
The name became a genericized trademark in various countries and languages, including English (widia, ), although the genericized sense was never especially widespread in English ("carbide" is the normal generic term). Since 2009, the name has been revived as a brand name by Kennametal, and the brand subsumes numerous popular brands of cutting tools.
Uncoated tips brazed to their shanks were the first form. Clamped indexable inserts and today's wide variety of coatings are advances made in the decades since. With every passing decade, the use of carbide has become less "special" and more ubiquitous.
Regarding fine-grained hardmetal, an attempt has been made to follow the scientific and technological steps associated with its production; this task is not easy, though, because of the restrictions placed by commercial, and in some cases research, organisations, in not publicising relevant information until long after the date of the initial work. Thus, placing data in an historical, chronological order is somewhat difficult. However, it has been possible to establish that as far back as 1929, approximately 6 years after the first patent was granted, Krupp/Osram workers had identified the positive aspects of tungsten carbide grain refinement. By 1939, they had also discovered the beneficial effects of adding a small amount of vanadium and tantalum carbide. This effectively controlled discontinuous grain growth.
What was considered 'fine' in one decade was considered not so fine in the next. Thus, a grain size in the range 0.5–3.0 μm was considered fine in the early years, but by the 1990s, the era of the nano-crystalline material had arrived, with a grain size of 20–50 nm.
Pobedit
Pobedit () is a sintered carbide alloy of about 90% tungsten carbide as a hard phase, and about 10% cobalt (Co) as a binder phase, with a small amount of additional carbon. Developed in the Soviet Union in 1929, it is described as a material from which cutting tools are made. Later a number of similar alloys based on tungsten and cobalt were developed, and the name of 'pobedit' was retained for them as well.
Pobedit is usually produced by powder metallurgy in the form of plates of different shapes and sizes. The manufacturing process is as follows: a fine powder of tungsten carbide (or other refractory carbide) and a fine powder of binder material such as cobalt or nickel both get intermixed and then pressed into the appropriate forms. Pressed plates are sintered at a temperature close to the melting point of the binder metal, which yields a very tight and solid substance.
The plates of this superhard composite are applied to manufacturing of metal-cutting and drilling tools; they are usually soldered on the cutting tool tips. Heat post-treatment is not required. The pobedit inserts at the tips of drill bits are still very widespread in Russia.
See also
Carbide saw
References
Bibliography
Further reading
External links
Carbides
Superhard materials
Tungsten compounds
Metalworking tools | Cemented carbide | Physics | 2,505 |
78,055,989 | https://en.wikipedia.org/wiki/IRAS%2007598%2B6508 | IRAS 07598+6508 known as IRAS F07599+6508, is a quasar located in the constellation of Camelopardalis. It is located 2.37 billion light years from Earth and is classified as both an ultraluminous infrared galaxy and a Seyfert galaxy.
Characteristics
IRAS 07598+6508 is categorized an advanced galaxy merger. It shows several tidal features according to ground-based optical images. A patchy emission is found having a low-surface brightness of around 22 R magnitude arcsec−2 ,based on Hubble Space Telescope (HST) imaging on the host galaxy. This emission is suggestive of tidal debris created by a recent galaxy-to-galaxy interaction. A deep R-band image reveals the presence of an extended tidal tail from north to east direction. It has a dynamical age of ~ 160 Myr and is curving towards south of the nucleus by ~ 50 kiloparsecs (kpc). Since one tidal tail is clearly seen, the merger was probably caused from the interaction of a spiral and elliptical galaxy.
In addition, IRAS 07598+6508 has several star clusters located both west and south, based on a HST optical image. The galaxy is infrared bright with a source having an estimated luminosity of L2-10keV = 1.12 x 1042 erg s−1.
IRAS 07598+6508 is a low-redshift broad absorption line quasar according to Sebastian Lipari and by ROSAT. It shows abnormally large blueshifts by 3000 km s−1 to a Balmer line as well as sodium (Na I) λ5892 at emission peaks. When looking at both Hα and Hβ intensity ratios, a broad emission line in IRAS 07598+6508 is found reddening by E(B-V) ~ 0.45 with a reddening of a spectral energy distribution of E(B-V) ~ 0.12.
IRAS 07598+6508 is also known to be a strong ferrous (Fe II) emitter although X-ray quiet with a value of αox = 2.45. It has a spectrum being influenced by its tapered broad line region with a full width at half maximum measurement of 1780 km s−1. Besides iron, IRAS 07598+6508 emits spectral lines of titanium (Ti II) and chromium (Cr II). Given its strong Fe II emission, the emission likely derived from a superbubble or was caused by ejected material from a type II supernovae.
Optical HST imaging found two emission clumps, located ~ 7" southeast and south from IRAS 07598+6508. This presence of clumps indicates the emission originates from OB associations and is the key to signs of recent star formation in the galaxy. A NICMOS image of IRAS 07598+6508, finds electromagnetic radiation is controlled by a source of light from the nucleus although low-level emission is also visible right up to ~ 2" radius.
References
External links
IRAS 07598+6508 on SIMBAD
Quasars
Camelopardalis
Galaxy mergers
Seyfert galaxies
097524
F07599+6508
Luminous infrared galaxies | IRAS 07598+6508 | Astronomy | 688 |
3,265,205 | https://en.wikipedia.org/wiki/Directional%20symmetry%20%28time%20series%29 | In statistical analysis of time series and in signal processing, directional symmetry is a statistical measure of a model's performance in predicting the direction of change, positive or negative, of a time series from one time period to the next.
Definition
Given a time series with values at times and a model that makes predictions for those values , then the directional symmetry (DS) statistic is defined as
Interpretation
The DS statistic gives the percentage of occurrences in which the sign of the change in value from one time period to the next is the same for both the actual and predicted time series. The DS statistic is a measure of the performance of a model in predicting the direction of value changes. The case would indicate that a model perfectly predicts the direction of change of a time series from one time period to the next.
See also
Statistical finance
Notes and references
Drossu, Radu, and Zoran Obradovic. "INFFC data analysis: lower bounds and testbed design recommendations." Computational Intelligence for Financial Engineering (CIFEr), 1997., Proceedings of the IEEE/IAFE 1997. IEEE, 1997.
Lawrance, A. J., "Directionality and Reversibility in Time Series", International Statistical Review, 59 (1991), 67–79.
Tay, Francis EH, and Lijuan Cao. "Application of support vector machines in financial time series forecasting." Omega 29.4 (2001): 309–317.
Xiong, Tao, Yukun Bao, and Zhongyi Hu. "Beyond one-step-ahead forecasting: Evaluation of alternative multi-step-ahead forecasting models for crude oil prices." Energy Economics 40 (2013): 405–415.
Symmetry
Signal processing | Directional symmetry (time series) | Physics,Mathematics,Technology,Engineering | 354 |
9,797,914 | https://en.wikipedia.org/wiki/Canadian%20Land%20Surface%20Scheme | The Canadian Land Surface Scheme (CLASS) is a land surface parametrization scheme for use in large scale climate models. It is a state-of-the-art model, using physically based equations to simulate the energy and water balances of vegetation, snow and soil. CLASS is being developed in a research project led by D. Verseghy at the Canadian Atmospheric Environment Service.
See also
CCCma - CLASS is used in CGCM3.1
References
D. L. Verseghy, "The Canadian Land Surface Scheme (CLASS): its history and future," Atmosphere-Ocean, vol. 38, no. 1, pp. 1-13, 2000.
D. L. Verseghy, "CLASS--A Canadian Land Surface Scheme for GCMS: I. Soil Model," International Journal of Climatology IJCLEU, vol. p 111-133, p. 44, 1991.
D. L. Verseghy, N. A. McFarlane, and M. Lazare, "CLASS-A Canadian land surface scheme for GCMS, II. Vegetation model and coupled runs," Int. J. Climatol., vol. 13, no. 4, pp. 347-370, 1993.
External links
CLASS
Land Surface Processes
Numerical climate and weather models
Hydrology models | Canadian Land Surface Scheme | Biology,Environmental_science | 277 |
20,158,495 | https://en.wikipedia.org/wiki/Diheterospora%20zeaspora | Diheterospora zeaspora (also known as Rotiferophthora zeaspora) is a rare species of fungus. It parasitizes animals known as rotifers.
References
External links
Catalogue of Life 2011 Annual Checklist
Diheterospora zeaspora at Mycobank
Hypocreales
Animal fungal diseases
Fungus species | Diheterospora zeaspora | Biology | 76 |
27,271,259 | https://en.wikipedia.org/wiki/Space%20mirror | Solar mirrors in space can be used to change the amount of sunlight that reaches the Earth. The concept was first theorised in 1923 by physicist Hermann Oberth and later developed in the 1980s by other scientists. Space mirrors can be used to increase or decrease the amount of solar energy that reaches a specific point of the earth for various purposes.
There have been several proposed implementations of the space mirror concept but none have been implemented thus far other than the Znamya experiment by Russia, due to logistical concerns and challenges of deployment. Znamya successfully tested reflecting more sunlight to Earth.
They were theorised as a method of climate engineering through shading the Earth by creating a space sunshade to deflect sunlight and counter global warming.
History
The concept of constructing space mirrors as a method of climate engineering dates to the years 1923, 1929, 1957 and 1978 by the physicist Hermann Oberth and the 1980s by other scientists. In 1923, Hermann Oberth first described his space mirrors with a diameter of 100 to 300 km in his book Die Rakete zu den Planetenräumen, which are said to consist of a grid network of individually adjustible facets.
Space mirrors in orbit around the Earth, as designed by Hermann Oberth, are intended to focus sunlight on individual regions of the earth's surface or deflect it into space.
It is therefore not a question of the weakening of the solar radiation on the entire exposed surface of the Earth, as would be the case when considering the establishment of shading areas at Lagrange point between the Sun and the Earth. These giant mirrors in orbit could be used to illuminate individual cities, as a means of protection against natural disasters, to control weather and climate, to create additional living space for tens of billions of people, Hermann Oberth writes. The fact that this could influence the trajectories of the barometric high and low pressure areas with these spatial mirrors seemed most important to Oberth.
The physicist Hermann Oberth followed his first suggestion in 1923 with further publications, in which he took into account the technical progress achieved up to that point: 1929 „Ways to Spaceflight“, 1957 „Menschen im Weltraum. Neue Projekte für Raketen- und Raumfahrt“ (People in Space. New Projects for Rocket and Space Travel) and 1978 „Der Weltraumspiegel“ (The Space Mirror). For cost reasons, Hermann Oberth's concept envisages that the components should be produced from lunar minerals on the Moon, because its lower gravitational pull requires less energy to launch the components into lunar Orbit. In addition, the earth's atmosphere is not burdened by many rocket launches. From the lunar surface, the components would be launched into the lunar orbit by an electromagnetic lunar slingshot and „stacked“ at a 60° libration point. From there, the components could be transported into orbit with the electric spaceships he had designed with little recoil, and there they would be assembled into mirrors with a diameter of 100 to 300 km. In 1978 he estimated that the realization could be expected between 2018 and 2038.
Other scientists proposed in the 1980s to cool Venus’ climate to provide for a theoretical future where humans occupy other planets. In 1989, James Early, working at the Lawrence Livermore National Laboratory, proposed using a "space shade" in diameter orbiting at Lagrangian Point L1. He estimated the cost at between one and ten trillion US dollars and suggested manufacturing it on the Moon using Moon rock.
Purpose
Space mirrors are designed either to increase or decrease the amount of energy that reaches a planet from the sun with the goal of changing the impact of UV radiation; or, to reflect light onto or deflect light off of a planet in order to change the sun's lighting conditions. Space mirrors are an example of Solar Radiation Management (SRM), which is a "theoretical approach to reducing some of the impacts of climate change by reflecting a small amount of inbound sunlight back out into space." The concept is to reflect enough sunlight to reduce the Earth's temperature thereby balancing out the warming effect of greenhouse gases.
Most past proposals for the development of space mirrors are specifically to slow the progression of global warming on Earth. Deflecting a small amount of the sun's energy from the Earth's atmosphere would reduce the amount of energy entering the ecosystem of the Earth.
Some proposals for the development of space mirrors also focus on the ability to change localized lighting conditions on the surface of the Earth by shading certain sections or reflecting sunlight onto small sections. Doing this could allow for differentiated climates in local areas and potentially additional sunlight for enhanced crop growth. A first practical attempt at reflecting sunlight was made in the 1990s by the Russian Agency project name Znamya.
Scientific theory
Geoengineering research efforts to mitigate or reverse global warming can be separated into two different categories, carbon dioxide removal and solar radiation management. Carbon dioxide is the main source for climate change on Earth as it causes an increase in the atmospheric temperature and acidification of the oceans. Although CO2 removal from the atmosphere would reverse climate changes thus far, removing carbon is a slower and more difficult process compared to solar radiation management.
Solar radiation management works to directly mitigate the effects of atmospheric warming due to the burning of fossil fuels and subsequent release of greenhouse gases. Space mirrors fall under this category of geoengineering as they work to block solar radiation and lower the warming effects from the Sun.
Scientific studies and proposals
There has been a range of proposals to reflect or deflect solar radiation from space, before it even reaches the atmosphere, commonly described as a space sunshade. The most straightforward is to have mirrors orbiting around the Earth—an idea first suggested even before the wider awareness of climate change, with rocketry pioneer Hermann Oberth considering it a way to facilitate terraforming projects in 1923. and this was followed by other books in 1929, 1957 and 1978. By 1992, the U.S. National Academy of Sciences described a plan to suspend 55,000 mirrors with an individual area of 100 square meters in a Low Earth orbit. Another contemporary plan was to use space dust to replicate Rings of Saturn around the equator, although a large number of satellites would have been necessary to prevent it from dissipating. A 2006 variation on this idea suggested relying entirely on a ring of satellites electromagnetically tethered in the same location. In all cases, sunlight exerts pressure which can displace these reflectors from orbit over time, unless stabilized by enough mass. Yet, higher mass immediately drives up launch costs.
In an attempt to deal with this problem, other researchers have proposed Inner lagrangian point between the Earth and the Sun as an alternative to near-Earth orbits, even though this tends to increase manufacturing or delivery costs instead. In 1989, a paper suggested founding a lunar colony, which would produce and deploy diffraction grating made out of a hundred million tonnes of glass. In 1997, a single, very large mesh of aluminium wires "about one millionth of a millimetre thick" was also proposed. Two other proposals from the early 2000s advocated the use of thin metallic disks 50–60 cm in diameter, which would either be launched from the Earth at a rate of once per minute over several decades, or be manufactured from asteroids directly in orbit.
When summarizing these options in 2009, the Royal Society concluded that their deployment times are measured in decades and costs in the trillions of USD, meaning that they are "not realistic potential contributors to short-term, temporary measures for avoiding dangerous climate change", and may only be competitive with the other geoengineering approaches when viewed from a genuinely long (a century or more) perspective, as the long lifetime of L1-based approaches could make them cheaper than the need to continually renew atmospheric-based measures over that timeframe.
In 2021, researchers in Sweden considered building solar sails in the near-Earth orbit, which would then arrive to L1 point over 600 days one by one. Once they all form an array in situ, the combined 1.5 billion sails would have total area of 3.75 million square kilometers, while their combined mass is estimated in a range between 83 million tons (present-day technology) and 34 million tons (optimal advancements). This proposal would cost between five and ten trillion dollars, but only once launch cost has been reduced to US$50/kg, which represents a massive reduction from the present-day costs of $4400–2700/kg for the most widely used launch vehicles.
Research and development proposals
In 2002, the aerospace consulting company STAR Technology and Research proposed a concept which, like Hermann Oberth's concept, uses the near-Earth orbit. Star's experts calculated that a network of steerable space mirrors orbiting Earth's equator, like one of the rings of Saturn, could lower the average air temperature by up to 3 degrees Celsius (5.4 degrees Fahrenheit) while simultaneously generating power from onboard solar panels and beaming it to Earth. But such an approach could generate problems. Report author and Star Technology president Jerome Pearson calculated it would take 5 million spacecraft to achieve the desired result, and even if each individual craft could last 100 years, that means 137 ships would have to be replaced or repaired per day. And the craft would produce "stars" that would be visible from the ground. (Pearson's other hypothetical proposal, a ring of reflective rocks in the same position, would light the night sky with the equivalent of 12 full moons.).
In the 1980s there were more theoretical proposals for space mirrors as scientists attempted to discover a feasible way to partially reflect sunlight and slow down the warming of the Earth's atmosphere using space mirrors. In 1989, engineer James Early proposed a 2,000 km glass shield. The glass shield would need to be constructed on the Moon using moon rock due to its sheer mass. Lowell Wood, a researcher at the Lawrence Livermore National Laboratory, proposed sending a single, massive mirror into orbit at Lagrange point L1, approximately one million miles away from Earth. While orbiting at the Lagrange point 1, the space mirror would be able to remain in orbit without any additional energy supplies and continue to block sunlight. In 2006, Roger Angel, a researcher at the University of Arizona, proposed sending millions of smaller space mirrors as opposed to one large mirror to reduce costs and increase feasibility as a single mirror would need to be approximately 600,000 square miles to block just one percent of sunlight.
Russian space mirror experiments
The Znamya project was a series of orbital mirror experiments in the 1990s that intended to beam solar power to Earth by reflecting sunlight. It consisted of three experiments the Znamya 1, Znamya 2 experiment, and the failed Znamya 2.5. The Znamya 1 was a ground experiment that never was launched. The Znamya 2 was the first successful launch the Znamya project had. It was attached to the unmanned Progress M-15.The deployment resulted in a bright light of a width of 5km and with the intensity of a Full Moon being shined. The Znamya 3 was proposed but never acted upon because of the failure of the Znamya 2.5. The project was abandoned by the Russian Federal Space Agency after the failed deployment of the Znamya 2.5.
Challenges
After the Russian Znamya space mirror experiment in 1993, there has not been any active development of space mirrors due to the sheer challenges involved in their deployment and the potential consequences that follow their operation.
Climate experts have cautioned that geoengineering proposals like space mirrors, while potentially being able to cool the planet, would not provide any benefit for other climate related problems like high acidity levels in the ocean due to the build up of carbon. In the past, many scientists have also resisted the idea of using geoengineering to curb climate change, as the risks of causing adverse effects were too great and they worried it would encourage people to continue to use fossil fuels that contribute to that change.
Policy
In January 2007, The Guardian reported that the US government recommended that research on sunlight deflection, including space mirrors, be continued in line with the next United Nations Report on Climate Change. In addition to the space mirror, suggested sunlight-reducing techniques included launching thousands of highly reflective balloons and pumping sulphate droplets into the upper atmosphere to emulate volcanic emissions.
Andrew Yang, a Democratic US presidential candidate in 2020, revived the space mirror movement with his expandable space mirror initiative. According to Yang's proposal, US researchers need to create satellites, similar to those already in orbit, equipped with retractable space mirrors with the ability to deploy and retract quickly and easily in case of an emergency.
Deployment logistics
The deployment and maintenance of a fleet of small space mirrors that can create a shade of around 100,000 kilometers in space would include necessary factors such as energy, construction, transportation, and ground support operations. Overall, the estimated cost of constructing and sending a fleet of space mirrors to space is around 750 billion dollars. If the space mirrors are able to achieve a 50-year lifetime, the annual maintenance cost estimates to around 100 billion dollars. Furthermore, if any individual satellite needed to be replaced at the end of their lifetime, the costs of the entire operation would amount to 5 trillion dollars.
The deployment of either one large space mirror or a fleet of smaller mirror will also have to take into consideration of the millions of space debris within the Earth's orbit. Most debris is small, weighing around 1 gram. However, depending on their speed, such debris can be catastrophic for satellites if they were to collide. Therefore, orbital satellites would need to maneuver out of the path of tracked space debris from the space mirror. Additionally, if one very large space mirror were to be deployed, its massive surface area will be a very large target for space debris. Therefore, maneuvering hundreds of space mirrors or one very large space mirror will prove to be very difficult due to the space debris and the potential size of the space mirror.
Unintended climate change
The direct reflection of solar radiation away from the Earth may have certain adverse effects on the climate. As the Earth is exposed to less solar radiation, the planet will cool down, but this might result in unpredictable weather patterns. An overall drop in global temperature may affect the hydrological cycle and could increase the intensity of droughts and floods. Furthermore, the change of temperature and climate may also negatively impact the cultivation of crops. As a result, the reflection of solar radiation could adversely affect around 65% of the global population.
See also
Planetary engineering
Space-based solar power
Sun gun
References
Climate change mitigation
Climate engineering
Satellites
Mirrors
1923 in science | Space mirror | Astronomy,Engineering | 3,009 |
58,070,834 | https://en.wikipedia.org/wiki/Non%20functional%20pad | A non-functional pad is a pad in a printed circuit board that is not connected to a track on the layer it is on.
Removal
Non-functional pads can be removed at any phase of the design process. Some software allows precise control during the design process, and also removes the non-functional pads during output file creation. Furthermore, some board manufacturers remove non-functional pads during data preparations.
Occasionally, this process of non-functional pad removal is also called unused pad suppression.
The benefits of removing the non-functional pads are limited. Electrically, it creates needless extra capacitance in certain designs, which needs to be removed. Removing non-functional pads can improve the drilling process, as it lessens drill wear.
Non-functional pad removal can influence the reliability. (e.g. barrel cracking failure mode). Removal can increase or decrease reliability. Depending on design parameters, removing the non-functional pads can free up routing space.
Non-functional pads naturally also affect thermal characteristics.
Sometimes, non-functional pads (or their removal) are used for copper balancing, which affects etching, bow and twist and other effects.
Bibliography
Non-functional Pads: Should They Stay or Should They Go
Pads/Nopads
Printed circuit board manufacturing | Non functional pad | Engineering | 256 |
170,375 | https://en.wikipedia.org/wiki/Chengdu | Chengdu is the capital city of the Chinese province of Sichuan. With a population of 20,937,757 at the 2020 census, it is the fourth most populous city in China, and it is the only city with a population of over 20 million apart from direct-administered municipalities. It is traditionally the hub of Western China.
Chengdu is in central Sichuan. The surrounding Chengdu Plain is known as the "Country of Heaven" and the "Land of Abundance". Its prehistoric settlers included the Sanxingdui culture. The site of Dujiangyan, an ancient irrigation system, is designated as a World Heritage Site. The Jin River flows through the city. Chengdu's culture reflects that of its province, Sichuan; in 2011, it was recognized by UNESCO as a city of gastronomy. It is associated with the giant panda, a Chinese national symbol that inhabits the area of Sichuan; the city is home to the Chengdu Research Base of Giant Panda Breeding.
Founded by the Kingdom of Shu in the 4th century BC, Chengdu is unique as the only major Chinese settlement that has maintained its name unchanged throughout the imperial, republican, and communist eras for more than two thousand years. It was the capital of Liu Bei's Shu Han Empire during the Three Kingdoms Era, as well as several other local kingdoms during the Middle Ages. During World War II, refugees from eastern China fleeing from the Japanese settled in Chengdu. After the war, Chengdu was briefly the capital of the Nationalist republican government until it withdrew to Taipei on the island of Taiwan. Under the PRC, Chengdu's importance as a link between Eastern China and Western China expanded, with railways built to Chongqing in 1952, and Kunming and Tibet afterward. In the 1960s, Chengdu became an important defense industry hub.
Chengdu is now one of the most important economic, financial, commercial, cultural, transportation, research, and communication centers in China. Its economy is diverse, characterized by the machinery, automobile, medicine, food, and information technology industries. Chengdu is a leading financial hub, ranking 35th globally on the 2021 Global Financial Centres Index. Chengdu also hosts many international companies; more than 300 Fortune 500 companies have established branches in Chengdu. Chengdu is the third Chinese city with two international airports after Beijing and Shanghai. Chengdu Shuangliu International Airport, and the newly built Tianfu International Airport, a hub of Air China and Sichuan Airlines, is one of the 30 busiest airports in the world, and the Chengdu railway station is one of the six biggest in China. Chengdu is considered a "Beta + (global second-tier)" city classification (along with Barcelona and Washington, D.C.) according to the GaWC. As of 2023, the city also hosts 23 foreign consulates, the fourth most in China behind Beijing, Shanghai, and Guangzhou. Chengdu is the seat of the Western Theater Command region of the People's Liberation Army. In 2023, Chengdu became the third Chinese city to host the 31st FISU Summer World University Games, after Beijing 2001 and Shenzhen 2011. The city will also host the 2025 World Games. It is considered one of the best cities in China to live in, and also a national central city of China.
Chengdu is one of the world's top 25 cities by scientific research output. The city is home to the greatest number of universities and research institutes in Western China. Notably, these include: Sichuan University, University of Electronic Science and Technology of China, Southwestern University of Finance and Economics, Southwest Jiaotong University, Chengdu University of Technology, Sichuan Normal University, and Xihua University.
Name
The name Chengdu is attested in sources dating back to the Warring States period. It has been called the only major city in China to have remained at an unchanged location with an unchanged name throughout the imperial, republican, and communist eras. However, it also had other names; for example, it was briefly known as "Xijing" (Western Capital) in the 17th century. Etymology of the name is unclear. The earliest and most widely known explanation, although not generally accepted by modern scholars, is provided in the 10th-century geographical work Universal Geography of the Taiping Era, which states that the ninth king of Shu's Kaiming dynasty named his new capital Chengdu after a statement by King Tai of Zhou that a settlement needed "one year to become a town, two to become a city, and three to become a metropolis." (The character for cheng may mean "turned into" while du can mean either a metropolis or a capital).
The present spelling is based on pinyin romanization; its Postal Map romanization was "Chengtu". Its former status as the seat of the Chengdu Prefecture prompted Marco Polo's spellings "Sindafu", "Sin-din-fu", &c. and the Protestant missionaries' romanization "Ching-too Foo".
Although the official name of the city has remained (almost) constant, the surrounding area has sometimes taken other names, including "Yizhou". Chinese nicknames for the city include the , variously derived from the old city walls' shape on a map or a legend that Zhang Yi had planned their course by following a turtle's tracks; the (see Sichuan brocade), a contraction of the earlier "City of the Brocade Official", after an imperial office established under the Western Han; the (Rongcheng, 蓉城), from the hibiscus which King Meng Chang of the Later Shu ordered planted upon the city wall during the 10th century.
According to Étienne de la Vaissière, "Baghshūr" () may be the Sogdian name for the region of Chengdu. This toponym is attested near Merv, but
not far from Chengdu are found the large salt water wells of the Yangtze basin.
Logo
The city logo adopted in 2011 is inspired by the Golden Sun Bird, an ancient relic unearthed in 2001 from the Jinsha Site.
History
Early history
Archaeological discoveries at the Sanxingdui and Jinsha Site have established that the area surrounding Chengdu was inhabited over four thousand years ago, in the 18th–10th centuryBC. At the time of China's Xia, Shang, and Zhou dynasties, it represented a separate ancient bronze-wielding culture that, following its partial sinification, became known to the Chinese as Shu. Shu was conquered by Qin in 316BC, and the settlement was re-founded by Qin general Zhang Yi.
Pre-Qin to Qin and Han dynasties
In the early stage of the Xia dynasty or even earlier, the ancient Shu Kingdom located on the Chengdu Plain has formed a relatively developed bronze civilization, becoming an important source of Chinese civilization and one of the birthplaces of the Chinese nation. According to records, there were five dynasties in the ancient Shu Kingdom, and their capitals were Qushang (now Wenjiang District, Chengdu), Piyi (now Pidu District), Xindu, and Guangdu. At the end of the Spring and Autumn period (around the 4th century BC), the fifth King Kaiming moved the capital to Chengdu. According to "Taiping Huanyu Ji", the name of the city is borrowed from the history of the establishment of the capital in the Western Zhou dynasty. The allusions of Zhou Wang Qianqi's "one year, he lived in a cluster, two years became a city, and three years Chengdu," because of the name Chengdu, it has been used to this day. Therefore, Chengdu has become a rare city in China and the world that has not changed its name since its establishment. Some people think that Chengdu is a transliteration of ancient Shu place names. There is a saying that "Guangdu, Xindu and Chengdu" are collectively referred to as the "Three Capitals of Ancient Shu". Nowadays, there are many cultural relics of ancient Shu Kingdom in Chengdu Plain, such as Sanxingdui Ruins, Jinsha Ruins, Yufu Ancient City Ruins, Wangcong Temple, etc. Jinsha Ruins located in the urban area of Chengdu is a peak of the development of ancient Shu culture.
The Golden Mask of the Shang and Zhou dynasties at the Jinsha Site.
The ancient state of Shu was the first target to be conquered by the Qin state in the process of unifying the world. King Huiwen of Qin had prepared for this for many years, and opened up the Shiniu Road (that is, the Jinniu Road) from Qin to Shu. In 316 BC, King Huiwen of Qin took advantage of the mutual attack between Ba and Shu and sent Sima Cuo to lead his army into Shu along the Shiniu Road, capturing the land in a few months. After that, the king of Qin established three abolitions of Shu Hou, and finally established Shu County, and the county seat of Chengdu County was established in Chengdu, the former capital of Shu. In 311 BC, Zhang Yi of the Qin dynasty built the Chengdu city wall according to the system of the capital Xianyang, building a large city and a small city. In 256 BC, King Zhao of Qin appointed Li Bing as the governor of Shu County. During his tenure, he presided over the construction of the world-famous Dujiangyan Water Conservancy Project. The Chengdu Plain has been fertile and wild for thousands of miles since then. After decades of operation, Chengdu replaced Guanzhong Plain in the late Qin dynasty and was called the "Land of Abundance", and this reputation has continued to this day.
During the Han dynasty, the Chengdu economy, especially its brocade industry, prospered, becoming an important source of tribute to the court. The imperial court invested in Chengdu and specially set up Jinguan management and built "Jinguan City" in the southwest of Chengdu, "Jinguan City" and "Jincheng" becoming nicknames for Chengdu. In the second year of Emperor Ping of the Yuan dynasty, the population of Chengdu reached 76,000 households, or about 354,000 people, making it one of the most populous cities at that time. Towards the six major cities. In the third year of the reign of Emperor Jing of the Han dynasty (141 BC), the Wen Dang, the prefect of Shu County, established the world's earliest local government-run school, "Wenweng Shishi", in Chengdu. In the Han dynasty, Chengdu's literature and art also reached a high level. All the most famous literary masters in the Han dynasty were from Chengdu, including Sima Xiangru, Yang Xiong, and Wang Bao.
In the former Han dynasty, the whole country was divided into 14 prefectural governors' departments, among which the Yizhou governor was established in Luoxian (now Guanghan City, Sichuan), and the governor later moved to Chengdu. In the first year of Emperor Guangwu's reign (25 years) in the Eastern Han dynasty, Gongsun Shu established himself as the emperor in Chengdu, and the country's name was "married family". In the twelfth year of Jianwu in the Later Han dynasty (36 years), the Great Sima Wuhan of the Eastern Han dynasty finally captured Chengdu after five years of war, and his family perished. In the fifth year of Zhongping (188), Emperor Ling of Han, the court accepted Liu Yan's suggestion and changed the provincial governors to state shepherds with actual recruitment and command power. In the fifth year of Chuping (194), it moved to Chengdu. At that time, the Yizhou Provincial Governor's Department was the place where the Hu people in the Western Regions were operating.
Imperial era
Under the Han, the brocade produced in Chengdu became fashionable and was exported throughout China. A "Brocade Official" () was established to oversee its production and transaction. After the fall of the Eastern Han, Liu Bei ruled Shu Han, the southwestern of the Three Kingdoms, from Chengdu. His minister Zhuge Liang called the area the "Land of Abundance". Under the Tang, Chengdu was considered the second most prosperous city in China after Yangzhou. Both Li Bai and Du Fu lived in the city. Li Bai praised it as "lying above the empyrean." The city's present Caotang ("Grass Hall") was constructed in 1078 in honor of an earlier, more humble structure of that name erected by Du Fu in 760, the second year of his 4-year stay. The Taoist Qingyang Gong ("Green Goat Temple") was built in the 9th century.
Chengdu was the capital of Wang Jian's Former Shu from 907 to 925, when it was conquered by the Later Tang. The Later Shu was founded by Meng Zhixiang in 934, with its capital at Chengdu. Its second and last king, Meng Chang beautified the city by ordering hibiscus to be planted upon the city walls.
The Song conquered the city in 965, introducing the first widely used paper money in the world. Su Shi praised it as "the southwestern metropolis". At the fall of the Song, a rebel leader set up a short-lived kingdom known as Great Shu (, Dàshǔ). Allegedly the Mongols called for the death of a million people in the city but the city's population had less than 30,000 residents (not Chengdu prefecture). The aged males who had not fled were killed while in typical fashion, the women, children and artisans were enslaved and deported. During the Yuan dynasty, most of Sichuan's residents were deported to Hunan during the insurgency of the western ethnic tribes of western Sichuan. Marco Polo visited Chengdu and wrote about the Anshun Bridge or an earlier version of it.
At the fall of the Ming, the rebel Zhang Xianzhong established his Great Western Kingdom () with its capital at Chengdu; it lasted only from 1643 to 1646. Zhang was said to have massacred a large number of people in Chengdu and throughout Sichuan. In any case, Chengdu was said to have become a virtual ghost town frequented by tigers and the depopulation of Sichuan necessitated the resettlement of millions of people from other provinces during the Qing dynasty. Following the Columbian Exchange, the Chengdu Plain became one of China's principal sources of tobacco. Pi County was considered to have the highest quality in Sichuan, which was the center of the country's cigar and cigarette production, the rest of the country long continuing to consume snuff instead.
Modern era
In 1911, Chengdu's branch of the Railway Protection Movement helped trigger the Wuchang Uprising, which led to the Xinhai Revolution that overthrew the Qing dynasty.
During World War II, the capital city of China was forced to move inland from Nanjing to Wuhan in 1937 and from Wuhan to Chengdu, then from Chengdu to Chongqing in 1938, as the Kuomintang (KMT) government under Generalissimo Chiang Kai-shek ultimately retreated to Sichuan to escape from the invading Japanese forces. They brought with them into Sichuan business people, workers, and academics who founded many of the industries and cultural institutions which continue to make Chengdu an important cultural and commercial production center.
Chengdu became a military center for the KMT to regroup in the War of Resistance. Chengdu was beyond the reach of the Imperial Japanese ground forces and escort fighter planes. However, the Japanese frequently flew in the then-highly advanced twin-engine long-ranged G3M "Nell" medium bombers to conduct massive aerial bombardments of both civilian and military targets in Chongqing and Chengdu. The massed formation of the G3M bombers provided heavy firepower against Chinese fighter planes assigned to the defense of Chongqing and Chengdu, which continued to cause problems for the Japanese attacks.
Slow and vulnerable obsolescent Chinese fighter aircraft burning low-grade fuel were still sufficiently dangerous in the hands of capable pilots against the Japanese schnellbomber-terror bombing raiders; on 4 November 1939 for instance, Capt. Cen Zeliu (Wade-Giles: Shen Tse-Liu) led his 17th Fighter Squadron, 5th Fighter Group of seven cannon-equipped Dewoitine D.510 fighters in a level head-on attack against an incoming coming raid of 72 IJANF G3M bombers (Capt. Cen chose this tactic knowing that the operation of the Hispano-Suiza HS.404 20mm autocannon in his D.510 is likely to fail under the g-loads of a high-deflection diving attack), with Capt. Cen pummeling the lead G3M of the IJN's 13th Kōkūtai's CO Captain Kikushi Okuda with cannon fire, sending the G3M crashing down in flames over Chengdu, along with three other G3M bombers destroyed in the Chengdu raid that day. With the death of Captain Okuda in the air battle over Chengdu, the IJN became the highest-ranking IJN Air officer to be killed-in-action in the War of Resistance/World War II thus far.
In mid-late 1940, unknown to the Americans and European allies, the Imperial Japanese appeared in the skies over Chongqing and Chengdu with the world's most advanced fighter plane at the time: the A6M "Zero" fighter that dominated the skies over China against the increasingly obsolete Russian-made Polikarpov I-15/I-153s and I-16s that were the principal fighter planes of the Chinese Nationalist Air Force. This would later prove to be a rude awakening for the Allied forces in the Pacific War following the attack on Pearl Harbor. One of the first American ace fighter pilots of the war and original volunteer fighter pilot for the Chinese Nationalist Air Force, Major Huang Xinrui (nicknamed "Buffalo" by his comrades) died as a result of battling the Zero fighters along with his squadronmates Cen Zeliu and Lin Heng (younger brother of renowned architect Lin Huiyin) defending Chengdu on 14 March 1941.
Following the attack on Pearl Harbor at the end of 1941, the United States began setting up stations at airbases in China. In 1944, the American XX Bomber Command launched Operation Matterhorn, an ambitious plan to base B-29 Superfortresses in Chengdu and strategically bomb the Japanese Home Islands. The operating base was located in Xinjin Airport in the southwestern part of the Chengdu metropolitan area. Because the operation required a massive airlift of fuel and supplies over the Himalayas, it was not a significant military success, but it did earn Chengdu the distinction of launching the first serious retaliation against the Japanese homeland.
During the Chinese Civil War, Chengdu was the last city on the Chinese mainland to be held by the Kuomintang. President Chiang Kai-shek and his son Chiang Ching-kuo directed the defense of the city from the Chengdu Central Military Academy () until 1949, when Communist forces took the city on 27 December. The People's Liberation Army took the city without any resistance after a deal was negotiated between the People's Liberation Army and the commander of the KMT Army guarding the city. On 10 December the remnants of the Nationalist Chinese government evacuated to Taiwan.
The Chengdu Tianfu New Area is a sustainable planned city that will be outside of Central Chengdu. The city is also planned to be self-sustaining, with every residence being a two-minute walk from a park.
The Great City
In 2019, Chengdu overtook Shenzhen, China's technology hub, as the best-performing Chinese economy. The city has surged in population in the last two decades. Investments into a Europe-Chengdu Express Railway have been made, providing even more opportunity for the city to grow. As a way to preserve farmland and accommodate the growing population of Chengdu, China is building a hyper-dense satellite city centered around a central mass-transit hub called the Great City where any destination within the city is within a 15-minute walk. This proto-type city is intended to provide affordable, high-quality lifestyle, which provides people-oriented spaces that does not require a car to navigate.
Their current urban-planning focus in the city of Chengdu is to make the city 'a city within a park' rather than creating parks within a city. The Great City falls in line with the Chengdu 'park city' initiative, prioritizing the environment, public space and quality of life. It will consist of 15% park and green space and be situated on a area. Although 25% of the space will be dedicated to roads, one half of the roads will be pedestrian-oriented. This transit system provides direct transport to Chengdu itself. It is expected that the city will consume 48% less energy than cities of similar size.
The goal of the 'park city' project is to allow a city like Chengdu to compete with Beijing and Shanghai without stripping the city of its character. The city of Chengdu is already known for its focus on quality of life, which includes affordable housing, good public schools, trees and bike lanes.
Geography
The vast plain on which Chengdu is located has an elevation ranging from .
Northwest Chengdu is bordered by the high and steep Longmen Mountains in the north-west and in the west by the Qionglai Mountains, the elevation of which exceeds and includes Miao Jiling () and Xiling Snow Mountain (). The western mountainous area is also home to a large primitive forest with abundant biological resources and a giant panda habitat. East of Chengdu stands the low Longquan Mountains and the west bordering area of the hilly land of middle reaches of Min River, an area noted by several converging rivers. Since ancient times, Chengdu has been known as "the Abundant Land" owing to its fertile soil, favorable climate, and novel Dujiangyan Irrigation System.
Chengdu is located at the western edge of the Sichuan Basin and sits on the Chengdu Plain; the dominating terrain is plains. The prefecture ranges in latitude from 30° 05' to 31° 26' N, while its longitude ranges from 102° 54' to 104° 53' E, stretching for from east to west and south to north, administering of land. Neighboring prefectures are Deyang (NE), Ziyang (SE), Meishan (S), Ya'an (SW), and the Ngawa Tibetan and Qiang Autonomous Prefecture (N). The urban area, with an elevation of , features a few rivers, three of them being the Jin, Fu, and Sha Rivers. Outside of the immediate urban area, the topography becomes more complex: to the east lies the Longquan Mountains () and the Penzhong Hills (); to the west lie the Qionglai Mountains, which rise to in Dayi County. The highest point in Chengdu is Daxuetang (also known as Miaojiling) in Xiling Snow Mountain in Dayi County, with an altitude of 5,364 meters. The lowest point is the river bank at the exit of Tuojiang River in Jianyang City, with an altitude of 359 meters.
Climate
Chengdu has a monsoon-influenced humid subtropical climate (Köppen Cwa) and is largely warm with high relative humidity all year. It has four distinct seasons, with moderate rainfall concentrated mainly in the warmer months, and relieved from both sweltering summers and freezing winters. The Qin Mountains (Qinling) to the far north help shield the city from cold Siberian winds in the winter; because of this, the short winter is milder than in the Lower Yangtze. The 24-hour daily mean temperature in January is , and snow is rare but there are a few periods of frost each winter. The summer is hot and humid, but not to the extent of the "Three Furnaces" cities of Chongqing, Wuhan, and Nanjing, all of which lie in the Yangtze basin. The 24-hour daily mean temperature in July and August is around , with afternoon highs sometimes reaching ; sustained heat as found in much of eastern China is rare. Rainfall occurs most frequently and is concentrated in July and August, with very little of it in the cooler months. Chengdu also has one of the lowest annual sunshine totals nationally, with less sunshine annually than much of Northern Europe. With monthly percent possible sunshine ranging from 15 percent in December to 32 percent in August, the city receives 1006 hours of bright sunshine annually. Spring (March–April) tends to be sunnier and warmer in the day than autumn (October–November). The annual mean is , and extremes have ranged from to .
Administrative divisions
Chengdu is a sub-provincial city, serves as the capital of Sichuan. It has direct jurisdiction over 12 districts, 5 county-level cities and 3 counties:
Tianfu New Area
Chengdu Economic and Technological Development Zone
Chengdu Hi-tech Industrial Development Zone
Chengdu Tianfu Software Park
Chengdu Export Processing Zone
Cityscape
As of July 2013, the world's largest building in terms of floor area, the New Century Global Center, is located in the city. The structure is in size with of floor area, housing retail outlets, a movie theaters, offices, hotels, a water park with artificial beach and waves and a Mediterranean-style village comprising a large 5-star hotel, a skating rink and a 15,000-spot parking area.
Demographics
According to the 2020 Chinese census, the municipality had 20,937,757 inhabitants; the metropolitan area itself was home to 16,045,577 inhabitants including those of the 12 urban districts plus Guanghan City (in Deyang). Chengdu is the largest city in Sichuan and the fourth largest in China. 21,192,000 for 2021, adding more residents than any other city in the country.
As of 2015, the OECD (Organization for Economic Cooperation and Development) estimated the Chengdu metropolitan area's population to be 18.1 million.
Culture
In 2006, China Daily named Chengdu China's fourth-most-livable city.
Literature
Some of China's most important literature comes from Chengdu. The city has been home to literary giants, such as Sima Xiangru and Yang Xiong, two masters of Fu, a mixture of descriptive prose and verse during the Tang dynasty; Li Bai and Du Fu, the most eminent poets of the Tang and Song dynasties respectively; Yang Shen'an, a famous scholar of the Ming dynasty; and Guo Moruo and Ba Jin, two well-known modern writers. Chang Qu, a historian of Chengdu during the Jin dynasty, compiled the earliest local historical records, the Record of Hua Yang State. Zhao Chongzuo, a poet in Chengdu during the Later Shu Kingdom, edited Among the Flowers, the first anthology of Ci in China's history. Meng Chang, the king of Later Shu, wrote the first couplet for the Spring Festival, which says, "A harvest year accepts celebrations, good festivals foreshadow long springs."
In 2023, Chengdu hosted the 81st World Science Fiction Convention, having beat out Winnipeg, Canada, in site-selection voting in 2021.
Fine art
During the period of the Five Dynasties, Huang Quan, a painter in Chengdu, initiated the Fine-Brush Flower-and-Bird Painting School with other painters. At that time, "Hanlin Painting Academy" was the earliest royal academy in China.
Religion
Chengdu contains official, Roman Catholic and Protestant congregations, some of which are underground churches.
The Apostolic Vicariate of Szechwan (now known as Roman Catholic Diocese of Chengdu) was established on 15 October 1696. Artus de Lionne, a French missionary of Paris Foreign Missions Society, was appointed as the first Apostolic Vicar.
In 1890, the Canadian Methodist Mission was searching for more stations in Asia. In February 1891, Dr. , who had been Superintendent of the New York Methodist Mission Society of Central China recommended that Chengtu be its first Mission sight. During the meeting, it was proposed he lead this contingency; having built western hospitals, Boy's and Girl's schools at Missions he established on the Yangtze and Gan Rivers from 1866 – 1888. On 9 May 1891 Dr. Virgil Hart arrived in Chengtu and two weeks later bought a home and had it subdivided into living quarters and a dispensary, for the later arriving Missionary staff to move into.
On 24 June 1892, the doors of Chengtu's first Protestant Mission Headquarters were opened with over one thousand people of the community attending. The first Methodist religious service was held the following Sunday with only several attendants. The first western dispensary in Sichuan was opened 3 November 1892 with sixteen patients seeking care. The mission site became so popular that a larger space was secured near Chengtu's East Gate in the spring of 1893. This site is where the city's first Methodist church (Sï-Shen-Tsï Methodist Church) and hospital were built. These were later razed by rioting Chinese in 1895 and the Mission staff retreated to Chongqing and later Shanghai to escape the marauders. Dr. Virgil Hart traveled to Peking to demand redress and full payment of retribution was collected from Sichuan Viceroy Liu Ping Chang. The mission compound was quickly rebuilt only to be destroyed once more in the riots of 1901. These were rebuilt a third time and later missionaries would relocate and expand the Boys' and Girls' Schools just south of the city, dedicating the Divinity College as Hart College in 1914; a part of the West China Union University, that is now Sichuan University and the West China School of Medicine (Huaxiyida). During the Cultural Revolution, the Sï-Shen-Tsï Methodist Church building was no longer in use and the building was entrusted to the nearby Chengdu City Second People's Hospital for management. The hospital used the chapel as a kindergarten and the office of the hospital equipment department. In 1984, the hospital returned the chapel building to the church.
In December 2018 the authorities attempted to close a 500-member underground church, the Early Rain Covenant Church, led by Pastor Wang Yi. Over 100 members of the church were arrested including the pastor and his wife. The church's kindergarten and theological college were raided and the church's media outlets were closed down. Before his arrest, church member Li Yingqiang declared: "Even if we are down to our last five, worship and gatherings will still go on because our faith is real. […] Persecution is a price worth paying for the Lord." Police are said to have told one member that the church had been declared an illegal organisation. Chinese media were banned from reporting the events. Video footage which found its way onto western social media showed arrests and photographs alleged to be of injuries inflicted by the police. From a photo of . Jiang's detention warrant it appears that the authorities have charged the church's leaders with "inciting subversion of state power," which carries a maximum sentence of 15 years.
In 2012, a Chabad Jewish Center was established in Chengdu, after moving five times, a permanent location was secured at Wuhou District.
Theater
The saying "Shu opera towers above all other performances in the world" reflects the achievement of Sichuan opera and Zaju (an ancient form of comedic drama involving dancing, singing, poetry, and miming). In the city, the first named opera "Bullfighting" was written in the Warring States period. The first detailed recorded opera was staged in the royal court of Shu Kingdom during the Three Kingdom period. China's first clearly recorded Zaju was also performed in Chengdu. Tombs of witty Han dynasty poets were excavated in Chengdu. And face-changing masks and fire breathing remain hallmarks of the Sichuan opera.
Language
The native language in Chengdu is Sichuanese, otherwise referred as Sichuan dialect. More precisely, "Chengdu Dialect" () is widely used in lieu of "Sichuanese" due to the largely different accents of Sichuanese speakers residing elsewhere.
Culinary art and tea culture
The distinct characteristic of Sichuan cuisine is the use of spicy chilies and peppercorns. Famous local dishes include Mapo doufu, Chengdu Hot pot, and Dan Dan Mien. Both Mapo Doufu and Dan Dan Mien contain Sichuan peppers. An article by the Los Angeles Times (2006) called Chengdu "China's party city" for its carefree lifestyle. Chengdu has more tea houses and bars than Shanghai despite having less than half the population. In 2023, there were more than 30,000 teahouses in Chengdu, and there were 3,566 legally registered bars, nightclubs, and dance halls in the city. A statistical report in 2019 showed that Chengdu had more bars than Shanghai, becoming the city with the most bars in China. Chengdu's tea culture dates back over a thousand years, including its time as the starting point of the Southern Silk Road.
Chengdu is officially recognized and named by UNESCO as the "City of Gastronomy".
Teahouse
Tea houses are ubiquitous in the city and range from ornate traditional establishments with bamboo furniture to simple modern tea houses. Teas on offer include jasmine, longjing and biluochun tea. Tea houses are popular venues for playing mahjong, getting a massage or one's ears clean. Some larger tea houses offer live entertainment such as Sichuan opera performances.
Hot pot
Chengdu is known for its hot pot. Hot pot is a traditional Sichuanese dish, made by cooking vegetables, fish, and/or meat in boiling spicy broth. A type of food suitable for friends' gathering, hot pot attracts both local people and tourists. Hot pot restaurants can be found at many places in Chengdu.
Mahjong
Mahjong has been an essential part of most local peoples' lives. After daytime work, people gather at home or in the tea houses on the street to play Mahjong. On sunny days, local people like to play Mahjong on the sidewalks to enjoy the sunshine and also the time with friends.
Mahjong is the most popular entertainment choice among locals for several reasons. Chengdu locals have simplified the rules and made it easier to play as compared to Cantonese Mahjong. Also, Mahjong in Chengdu is a way to meet old friends and to strengthen family relationships. In fact, many business people negotiate deals while playing Mahjong.
Rural tourism: Nong Jia Le
Chengdu claims to have first practiced the modern business model of 'Nong Jia Le' (Happy Rural Homes). It refers to the practice of suburban and rural residents converting their houses into restaurants, hotels and entertainment spaces in order to attract city dwellers.
Nong Jia Le features different styles and price levels and have been thriving around Chengdu. They provide gateways for city dwellers to escape the city, offer delicious and affordable home-made dishes, and provide mahjong facilities.
Main sights
World natural and cultural heritage sites
Mount Qingcheng
Mount Qingcheng is amongst the most important Taoism sites in China. It is situated in the suburbs of Dujiangyan City and connected to downtown Chengdu away by the Cheng-Guan Expressway.
With its peak above sea level, Mount Qingcheng enjoys a cool climate, but remains a lush green all year round and surrounded by hills and waterways. Mount Qingcheng's Fujian Temple, Tianshi Cave, and Shizu Hall are some of the existing more well-known Taoist holy sites. Shangqing Temple is noted for an evening phosphorescent glow locally referred to as "holy lights".
Dujiangyan Irrigation System
The Dujiangyan Irrigation System ( away from downtown Chengdu) is the oldest existing irrigation project in the world with a history of over 2000 years diverting water without a dam to distribute water and filter sand with an inflow-quantity control. The system was built by Libing and his son. The irrigation system prevents floods and droughts throughout the Plain of Chengdu.
Sichuan Giant Panda Sanctuaries
Covering a total of over 12 distinct counties and 4 cities, Sichuan Giant Panda Sanctuaries, lie on the transitional alp-canyon belt between the Sichuan Basin and the Qinghai-Tibetan Plateau. It is the largest remaining continuous habitat for giant pandas and home to more than 80 percent of the world's wild giant pandas. Globally speaking, it is also the most abundant temperate zone of greenery. The reserves of the habitat are away from Chengdu.
The Sichuan Giant Panda Sanctuaries are the most well-known of their kind in the world, with Wolong Nature Reserve, generally considered as the "homeland of pandas". It is a core habitat with unique natural conditions, complicated landforms, and a temperate climate with diverse wildlife. Siguniang Mountain, sometimes called the "Oriental Alpine" is approximately away from downtown Chengdu, and is composed of four adjacent peaks of the Traversal Mountain Range. Among the four peaks, the fourth and highest stands above sea level, and is perpetually covered by snow.
Culture of poetry and the Three Kingdoms
Wuhou Shrine
Wuhou Shrine (Temple of Marquis Wu; 武侯祠) is perhaps the most influential museum of Three Kingdoms relics in China. It was built in the Western Jin period (265–316) in the honor of Zhuge Liang, the famous military and political strategist who was Prime Minister of the Shu Han State during the Three Kingdoms period (220–280). The Shrine highlights the Zhuge Liang Memorial Temple and the Hall of Liu Bei (founder of the Shu Han state), along with statues of other historical figures of Shu Han, as well as cultural relics like stone inscriptions and tablets. The Huiling Mausoleum of Liu Bei represents a unique pattern of enshrining both the emperor and his subjects in the same temple, a rarity in China.
Du Fu thatched cottage
Du Fu was one of the most noted Tang dynasty poets; during the Lushan-Shi Siming Rebellion, he left Xi'an (then Chang'an) to take refuge in Chengdu. With the help from his friends, the thatched cottage was built along the Huanhua Stream in the west suburbs of Chengdu, where Du Fu spent four years of his life and produced more than 240 now-famous poems. During the Song dynasty, people started to construct gardens and halls on the site of his thatched cottage to honor his life and memory. Currently, a series of memorial buildings representing Du Fu's humble life stand on the river bank, along with a large collection of relics and various editions of his poems.
Ancient Shu civilization
Jinsha Site
The Jinsha Site are the first significant archeological discovery in China of the 21st century and were selected in 2006 as a "key conservation unit" of the nation. The Jinsha Relics Museum is located in the northwest of Chengdu, about from downtown. As a theme-park-style museum, it is for the protection, research, and display of Jinsha archaeological relics and findings. The museum covers , and houses relics, exhibitions, and a conservation center.
Golden Sun Bird
The Golden Sun Bird was excavated by archaeologists from the Jinsha Ruins on 25 February 2001. In 2005, it was designated as the official logo of Chinese cultural heritage by the China National Relic Bureau.
The round, foil plaque dates back to the ancient Shu area in 210 BC and is 94.2 percent pure gold and extremely thin. It contains four birds flying around the perimeter, representing the four seasons and directions. The sun-shaped cutout in the center contains 12 sunlight beams, representing the 12 months of a year. The exquisite design is remarkable for a 2,200-year-old piece.
Sanxingdui Museum
Situated in the northeast of the state-protected Sanxingdui Site, The original complex of Sanxingdui Museum was founded in August 1992 and opened in 1997. It is the representative work of the master architect Zheng Guoying. The original museum covers an area of 1,000 acres and was rated as the first batch of national first-class museums.
The new complex of Sanxingdui Museum was founded in March 2022. It covers an area of 54,400 square meters, which is about 5 times the size of the old museum. It was built for new cultural relics after major archaeological excavations. It displays more than 2,000 precious cultural relics such as bronze, jade, gold, pottery, and bone, and comprehensively and systematically displays the archaeological excavations and latest research results of Sanxingdui.
The main collection highlights the Ancient City of Chengdu, Shu State & its culture, while displaying thousands of valuable relics including earthenware, jade wares, bone objects, gold wares, and bronzes that have been unearthed from Shang dynasty sacrificial sites.
Buddhist and Taoist culture
Daci Temple
The Daci Temple (大慈寺), a temple in downtown Chengdu was first built during the Wei and Jin dynasties, with its cultural height during the Tang and Song dynasties. Xuanzang, a Tang dynasty monk, was initiated into monkhood and studied for several years here; during this time, he gave frequent sermons in Daci Monastery.
Wenshu Monastery
Also named Xinxiang Monastery, Wenshu Monastery (文殊院) is the best preserved Buddhist temple in Chengdu. Initially built during the Tang dynasty, it has a history dating back 1,300 years. Parts of Xuanzang's skull are held in consecration here (as a relic). The traditional home of scholar Li Wenjing is on the outskirts of the complex.
Baoguang Buddhist Temple
Located in Xindu District, Baoguang Buddhist Temple (宝光寺) enjoys a long history and a rich collection of relics. It is believed that it was constructed during the East Han period and has appeared in written records since the Tang dynasty. It was destroyed during the Ming dynasty in the early 16th century. In 1607, the ninth year of the reign of the Kangxi Emperor of the Qing dynasty, it was rebuilt.
Qingyang Palace
Located in the western part of Chengdu, Qingyang Palace (青羊宫) is not only the largest and oldest Taoist temple in the city, but also the largest Taoist temple in Southwestern China. The only existing copy of the Daozang Jiyao (a collection of classic Taoist scriptures) is preserved in the temple.
According to history, Qingyang Temple was the place where Lao Tzu preached his famous Dao De Jing to his disciple, Ying Xi.
Featured streets and historic towns
Kuanzhaixiangzi Alleys
Kuanzhaixiangzi Alleys (宽窄巷子) were first built during the Qing dynasty for Manchu soldiers. The lanes remained residential until 2003 when the local government turned the area into a mixed-use strip of restaurants, teahouses, bars, avant-garde galleries, and residential houses. Historic architecture has been well preserved in the Wide and Narrow lanes.
Jinli
Nearby Wuhou Shrine, Jinli is a popular commercial and dining area resembling the style of traditional architecture of western Sichuan. "Jinli" () is the name of an old street in Chengdu dating from the Han dynasty and means "making perfection more perfect."
The ancient Jinli Street was one of the oldest and the most commercialized streets in the history of the Shu state and was well known throughout the country during the Qin, Han and Three Kingdoms periods. Many aspects of the urban life of Chengdu are present in the current-day Jinli area: teahouses, restaurants, bars, theaters, handicraft stores, local snack vendors, and specialty shops.
Huanglongxi Historic Town
Facing the Jinjiang River to the east and leaning against Muma Mountain to the north, the ancient town of Huanglongxi is approximately southeast of Chengdu. It was a large military stronghold for the ancient Shu Kingdom. The head of the Shu Han State in the Three Kingdoms period was seated in Huanglongxi, and for some time, the general government offices for Renshou, Pengshan, and Huayang counties were also located here. The ancient town has preserved the Qing dynasty architectural style, as seen in the design of its streets, shops, and buildings.
Chunxi Road
Located in the center of downtown Chengdu, Chunxi Road () is a trendy and bustling commercial strip with a long history. It was built in 1924 and was named after a part of the Tao Te Ching. Today, it is one of the most well-known and popular fashion and shopping centers of Chengdu, lined with shopping malls, luxury brand stores, and boutique shops.
Anren Historic Town
Anren Historic Town is located west of Chengdu. It was the hometown of Liu Wencai, a Qing dynasty warlord, landowner and millionaire. His 27 historic mansions have been well preserved and turned into museums. Three old streets built during the Republic of China period are still being used today by residents. Museums in Anren have a rich collection of more of than 8 million pieces of relics and artifacts. A museum dedicated to the memorial of the 2008 Sichuan earthquake was built in 2010.
Luodai Historic Town
Luodai was built, like many historic structures in the area, during the period of the Three Kingdoms. According to legend, the Shu Han emperor Liu Shan dropped his jade belt into a well when he passed through this small town. Thus, the town was named 'lost belt' (). It later evolved into its current name with the same pronunciation, but a different first character.
Luodai Historic Town is one of the five major Hakka settlements in China. Three or four hundred years ago, a group of Hakka people moved to Luodai from coastal cities. It has since grown into the largest community for Hakka people.
Economy
China's state council has designated Chengdu as the country's western center of logistics, commerce, finance, science and technology, as well as a hub of transportation and communication. It is also an important base for manufacturing and agriculture.
According to the World Bank's 2007 survey report on global investment environments, Chengdu was declared "a benchmark city for investment environment in inland China."
Also based on a research report undertaken by the Nobel economics laureate, Dr. Robert Mundell and the celebrated Chinese economist, Li Yining, published by the State Information Center in 2010, Chengdu has become an "engine" of the Western Development Program, a benchmark city for investment environment in inland China, and a major leader in new urbanization.
In 2010, 12 of the Fortune 500 companies, including ANZ Bank, Nippon Steel Corporation, and Electricité de France, have opened offices, branches, or operation centers in Chengdu, the largest number in recent years. Meanwhile, the Fortune 500 companies that have opened offices in Chengdu, including JP Morgan Chase, Henkel, and GE, increased their investment and upgraded the involvement of their branches in Chengdu. By the end of 2010, over 200 Fortune 500 companies had set up branches in Chengdu, ranking it first in terms of the number of Fortune 500 companies in Central and Western China. Of these, 149 are foreign enterprises and 40 are domestic companies.
According to the 2010 AmCham China White Paper on the State of American Business in China, Chengdu has become a top investment destination in China.
The main industries in Chengdu—including machinery, automobile, medicine, food, and information technology—are supported by numerous large-scale enterprises. In addition, an increasing number of high-tech enterprises from outside Chengdu have also settled down there.
Chengdu is becoming one of the favorite cities for investment in Central and Western China. Among the world's 500 largest companies, 133 multinational enterprises have had subsidiaries or branch offices in Chengdu by October 2009. These MNEs include Intel, Cisco, Sony and Toyota that have assembly and manufacturing bases, as well as Motorola, Ericsson, and Microsoft that have R&D centers in Chengdu. The National Development and Reform Commission has formally approved Chengdu's proposed establishment of a national bio-industry base there. The government of Chengdu had unveiled a plan to create a 90-billion-CNY bio pharmaceutical sector by 2012. China's aviation industries have begun construction of a high-tech industrial park in the city that will feature space and aviation technology. The local government plans to attract overseas and domestic companies for service outsourcing and become a well-known service outsourcing base in China and worldwide.
In the middle of the 2000s, the city expanded urban infrastructure and services to nearby rural communities in an effort to improve rural living conditions.
Electronics and IT industries
Chengdu has long been an established national electronics and IT industry hub. Chengdu's growth accelerated alongside the growth of China's domestic telecom services sector, which along with India's together account for over 70 percent of the world telecommunications market. Several key national electronics R&D institutes are located in Chengdu. Chengdu Hi-tech Industrial Development Zone has attracted a variety of multinationals, at least 30 Fortune 500 companies and 12,000 domestic companies, including Intel, IBM, Cisco, Nokia, Motorola, SAP, Siemens, Canon, HP, Xerox, Microsoft, Tieto, NIIT, MediaTek, and Wipro, as well as domestic powerhouses such as Lenovo. Dell opened its second major China operations center in 2011 in Chengdu as its center in Xiamen expands in 2010.
Intel Capital acquired a strategic stake in Primetel, Chengdu's first foreign technology company in 2001. Intel's Chengdu factory, set up in 2005 is its second in China, after its Shanghai factory, and the first such large-scale foreign investment in the electronics industry in interior mainland China. Intel, the world's largest chipmaker, has invested US$600 million in two assembly and testing facilities in Chengdu. Following the footsteps of Intel, Semiconductor Manufacturing International Corporation (SMIC), the world's third largest foundry, set up an assembly and testing plant in Chengdu in 2006. AMD, Intel's rival, had set up an R&D center in this city in 2008.
In November 2006, IBM signed an agreement with the Chengdu High-Tech Zone to establish a Global Delivery Center, its fourth in China after Dalian, Shanghai and Shenzhen, within the Chengdu Tianfu Software Park. Scheduled to be operational by February 2007, this new center will provide multilingual application development and maintenance services to clients globally in English, Japanese and Chinese, and to the IBM Global Procurement Center, recently located to the southern Chinese city of Shenzhen. On 23 March 2008, IBM announced at the "West China Excellent Enterprises CEO Forum" that the southwest working team of IBM Global Business Services is now formally stationed in Chengdu. On 28 May 2008, Zhou Weikun, president of IBM China disclosed that IBM Chengdu would increase its staff number from the present 600 to nearly 1,000 by the end of the year.
In July 2019, Amazon Web Services, the cloud computing company, signed a deal with the Chengdu High-Tech Zone to establish an innovation center. This project was intended to attract international business and enterprise into the area, promote cloud computing in China, and develop artificial intelligence technologies.
Chengdu is a major base for communication infrastructure, with one of China's nine top level postal centers and one of six national telecom exchanges hub.
In 2009, Chengdu hosted the World Cyber Games Grand Finals (11–15 November). It was the first time China hosted the world's largest computer and video game tournament.
Financial industry
Chengdu is a leading financial hub in the Asia-Pacific region and ranks 35th globally and 6th in China after (Shanghai, Hong Kong, Beijing, Shenzhen and Guangzhou) in the 2021 Global Financial Centres Index. Chengdu has attracted a large number of foreign financial institutions, including Citigroup, HSBC, Standard Chartered Bank, JPMorgan Chase, ANZ and MUFG Bank.
ANZ's data services center, established in 2011 in Chengdu, employs over 800 people, and in March 2019 the bank recruited further staff to support its data analytics and big data efforts. In 2020, ANZ temporarily repurposed its Chengdu data center to an IT helpdesk, as part of the bank's pandemic response.
Historically, Chengdu has marked its name in the history of financial innovation. The world's first paper currency 'Jiao Zi' was seen in Chengdu in the year 1023, during the Song dynasty.
Now, Chengdu is not only the gateway of Western China for foreign financial institutions, but also a booming town for Chinese domestic financial firms. The Chinese monetary authority, People's Bank of China (China's central bank), set its southwestern China headquarters in Chengdu City. In addition, almost all domestic banks and securities brokerage firms located their regional headquarters or branches in Chengdu. At the same time, the local financial firms of Chengdu are strengthening their presences nationally, notably, Huaxi Securities, Sinolink Securities, and Bank of Chengdu. Moreover, on top of banks and brokerage firms, the flourish of local economy lured more and more financial service firms to the city to capitalise on the economic growth. Grant Thornton, KPMG, PWC and Ernst & Young are the four global accountants and business advisers with Western China head offices in the city.
It is expected that by 2012, value-added financial services will make up 14 percent of the added-value service industry and 7 percent of the regional GDP. By 2015, those figures are expected to grow to 18 percent and 9 percent respectively.
Modern logistic industry
Because of its logistic infrastructure, professional network, and resources in science, technology, and communication, Chengdu has become home to 43 foreign-funded logistic enterprises, including UPS, TNT, DHL, and Maersk, as well as a number of well-known domestic logistic enterprises including COSCO, CSCL, SINOTRANS, CRE, Transfar Group, South Logistic Group, YCH, and STO. By 2012, the logistic industry in Chengdu will realize a value added of RMB 50 billion, with an average annual growth exceeding 18 percent. Ten new international direct flights will be in service; five railways for five-scheduled block container trains will be put into operation; and 50 large logistic enterprises are expected to have annual operation revenue exceeding RMB 100 million.
Modern business and trade
Chengdu is the largest trade center in western China with a market covering all of Sichuan province, exerting influence on six provinces, cities, and districts in western China. Chengdu ranks first among cities in western China in terms of the scale of foreign investment in commerce and trade. By 2012, total retail sales of consumer goods in Chengdu reached RMB 331.77 billion, up 16 percent annually on average.
Convention and exhibition industry
Boasting the claim as "China's Famous Exhibition City" and "China's Most Competitive Convention and Exhibition City", Chengdu takes the lead in central and western China for its scale of convention economy. It has been recognized as one of the three largest convention and exhibition cities in China. In 2010, direct revenue from the convention and exhibition industry was RMB 3.21 billion, with a year-on-year growth of 27.8 percent. The growth reached a historical high.
Software and service outsourcing industry
In 2006, Chengdu was listed as one of the first service outsourcing base cities in China by the Ministry of Science and Technology. Among the Top 10 service outsourcing enterprises in the world, Accenture, IBM, and Wipro are based in Chengdu. In addition, 20 international enterprises including Motorola, Ubi Soft Entertainment, and Agilent, have set up internal shared service centers or R&D centers in Chengdu. Maersk Global Document Processing Center and Logistic Processing Sub-center, DHL Chengdu Service Center, Financial Accounting Center for DHL China, and Siemens Global IT Operation Center will be put into operation. In 2010, offshore service outsourcing in Chengdu realized a registered contract value of US$336 million, 99 percent higher than the previous year.
New energy industry
Chengdu was granted the title "National High-Tech Industry Base for New Energy Industry" (新能源产业国家高技术产业基地) by the National Development and Reform Commission. Chengdu ranked first again in the list of China's 15 "Cities with Highest Investment Value for New Energies" released at the beginning of 2011, and Shuangliu County under its jurisdiction entered "2010 China's Top 100 Counties of New Energies". In 2012, Chengdu's new energy industry reached an investment over 20 billion RMB and sales revenue of 50 billion RMB.
Electronics and information industry
Chengdu is home to the most competitive IT industry cluster in western China, an important integrated circuit industry base in China, and one of the five major national software industry bases.
Manufacturing chains are already formed in integrated circuits, optoelectronics displays, digital video & audio, optical communication products, and original-equipment products of electronic terminals, including companies as IBM, Intel, Texas Instruments, Microsoft, Motorola, Nokia, Ericsson, Dell, Lenovo, Foxconn, Compal, and Wistron.
Automobile industry
Chengdu has built a comprehensive automobile industry system, and preliminarily formed a system integrated with trade, exhibitions, entertainment, R&D, and manufacturing of spare parts and whole vehicles (e.g., sedans, coaches, sport utility vehicles, trucks, special vehicles). There are whole vehicle makers, such as Dongfeng-PSA (Peugeot-Citroën), Volvo, FAW-Volkswagen, FAW-Toyota, Yema, and Sinotruk Wangpai, as well as nearly 200 core parts makers covering German, Japanese, and other lines of vehicles.
In 2011, Volvo announced that its first manufacturing base in China with an investment of RMB 5.4 billion was to be built in Chengdu. By 2015, the automobile production capacity of Chengdu's Comprehensive Function Zone of Automobile Industry is expected to reach 700,000 vehicles and 1.25 million in 2020.
Modern agriculture
Chengdu enjoys favorable agricultural conditions and rich natural resources. It is an important base for high-quality agricultural products. A national commercial grain and edible oil production base, the vegetable and food supply base as well as the key agricultural products processing center and the logistics distribution center of western China are located in Chengdu.
Defense industry
Chengdu is home to many defense companies such as the Chengdu Aircraft Company, which produces the recently declassified J-10 Vigorous Dragon combat aircraft as well as the JF-17 Thunder, in a joint collaborative effort with Pakistan Air Force. Chengdu Aircraft Company has also developed the J-20 Mighty Dragon stealth fighter. The company is one of the major manufacturers of Chinese Military aviation technology.
Industrial zones
Chengdu Hi-tech Comprehensive Free Trade Zone
Chengdu Hi-tech Comprehensive Free Trade Zone was established with the approval of the State Council on 18 October 2010 and passed the national acceptance on 25 February 2011. It was officially operated in May 2011. Chengdu High-tech Comprehensive Free Trade Zone is integrated and expanded from the former Chengdu Export Processing Zone and Chengdu Bonded Logistics Center. it is located in the Chengdu West High-tech Industrial Development Zone, with an area of 4.68 square kilometers and divided into three areas A, B and C. The industries focus on notebook computer manufacturing, tablet computer manufacturing, wafer manufacturing and chip packaging testing, electronic components, precision machining, and biopharmaceutical industry. Chengdu Hi-Tech Comprehensive Free Trade Zone has attracted top 500 and multinational enterprises including as Intel, Foxconn, Texas Instruments, Dell, and Morse.
In 2020, the Chengdu Hi-Tech Comprehensive Free Trade Zone achieved a total import and export volume of 549.1 billion yuan (including Shuangliu Sub-zone), accounting for 68% of the province's total foreign trade import and export volume, ranking No.1 in the national comprehensive free trade zones for three consecutive years.
Chengdu Economic and Technological Development Zone
Chengdu Export Processing Zone
Chengdu Hi-Tech Industrial Development Zone
Chengdu National Cross-Strait Technology Industry Development Park
This was established in 1992 as the Chengdu Taiwanese Investment Zone.
Built environments
In 1988, The Implementation Plan for a Gradual Housing System Reform in Cities and Towns marked the beginning of overall housing reform in urban areas of China. More than 20 real estate companies set up in Chengdu, which was the first step for Chengdu's real estate development.
The comprehensive Funan River renovation project in the 1990s had been another step towards promoting Chengdu environmental development. The Funan River Comprehensive Improvement Project won the UN-Habitat Scroll of Honour Award in 1998, as well as winning the "Local Initiative Award" by the International Council for Local Environmental Initiatives in 2000.
Chengdu started the Five Main Roads & One Bridge project in 1997. Three of the roads supported the east part of the city, the other two led to the south. It established the foundation of the Eastern and Southern sub-centers of Chengdu. The two major sub-centers determined people's eastward and southward living trends. Large numbers of buildings appeared around the east and south of the 2nd Ring Road. The Shahe River renovation project together with Jin River project also set off a fashion for people living by the two rivers. It was said that the map of Chengdu should update every three months.
A speculative housing boom occurred in the late 1990s and early 2000s. In 2000, dozens of commercial real estate projects also appeared. While promoting the real estate market, the Chinese government encouraged citizens to buy their own houses by providing considerable subsidies at a certain period. Houses were included in commodities.
Transport
Air
Chengdu is the third Chinese city with two international airports (Shuangliu International Airport and Chengdu Tianfu International Airport) after Beijing and Shanghai. Chengdu Shuangliu International Airport is located in Shuangliu County southwest of downtown. Chengdu Shuangliu International Airport is the busiest airport in Central and Western China and the nation's fourth-busiest airport in 2018, with a total passenger traffic of 53 million in 2018.
Chengdu airports (including Shuangliu International Airport and Tianfu International Airport) is also a 144-hour visa-free transit port for foreigners from 53 countries Besides, Chengdu airports also offer 24-hour visa-free transit for most nationals when having a stopover in Chengdu.
Chengdu Shuangliu International Airport has two runways and is capable of landing the Airbus A-380, currently the largest passenger aircraft in operation. Chengdu is the fourth city in China with two commercial-use runways, after Beijing, Shanghai and Guangzhou. On 26 May 2009, Air China, Chengdu City Government and Sichuan Airport Group signed an agreement to improve the infrastructure of the airport and increase the number of direct international flights to and from Chengdu. The objective is to increase passenger traffic to more than 40 million by 2015, making Chengdu Shuangliu International Airport the fourth-largest international hub in China, after Beijing, Shanghai and Guangzhou, top 30 largest airports in the world. Chengdu Shuangliu Airport ranked the No.1 and No.2 busiest airport in China in 2020 and 2021, respectively.
A second international airport, the Chengdu Tianfu International Airport currently with two main terminals and three runways, opened in June 2021. The new airport is southeast of the city and will have a capacity to handle between 80 and 90 million passengers per year.
Railway
Chengdu is the primary railway hub city and rail administrative center in southwestern China. The China Railway Chengdu Group manages the railway system of Sichuan Province, Chongqing City, and Guizhou Province. Chengdu has four main freight railway stations. Among them, the Chengdu North Marshalling Station is one of the largest marshalling stations in Asia. Since April 2013, companies are able to ship goods three times a week (initially only once a week) to Europe on trains originating from Chengdu Qingbaijiang Station bound for Łódź, Poland. It is the first express cargo train linking China and Europe, taking 12 days to complete the full journey.
There are four major passenger stations servicing Chengdu: Chengdu railway station (commonly referred to as the "North Station"), Chengdu South railway station (ChengduNan Station), Chengdu East railway station (ChengduDong Station), and Chengdu West railway station (ChengduXi Station). Additionally, Chengdu Tianfu Station is under construction.
Chengdu is the terminus of Baoji–Chengdu railway, Chengdu–Chongqing railway, Chengdu–Kunming railway, Chengdu–Dazhou railway, Shanghai–Wuhan–Chengdu high-speed railway, Chengdu-Lanzhou railway, Xi'an-Chengdu high-speed railway, Chengdu-Guiyang high-speed railway, Chengdu-Kunming high-speed railway and Chengdu–Dujiangyan high-speed railway.
The Chengdu–Dujiangyan high-speed railway is a high-speed rail line connecting Chengdu with the satellite city of Dujiangyan and the Mountain Qingcheng World Heritage Site. The line is in length with 15 stations. CRH1 train sets on the line reach a maximum speed of and complete the full trip in 30 minutes. The line was built in 18 months and entered operation on 12 May 2010.
Metropolitan expressways
Chengdu's transport network is well developed, and Chengdu serves as the starting point for many national highways, with major routes going from Sichuan–Shanxi, Sichuan–Tibet, and Sichuan–Yunnan.
Several major road projects have been constructed: a tunnel from Shuangliu Taiping to Jianyang Sancha Lake; alteration of the National Expressway 321, from Jiangyang to Longquanyi. There will also be a road that connects Longquan Town to Longquan Lake; it is connected to the Chengdu–Jianyang Expressway and hence shorten the journey by . By the end of 2008, there are ten expressways, connecting downtown Chengdu to its suburbs. The expressways are Chenglin Expressway, extensions of Guanghua Avenue, Shawan Line, and an expressway from Chengdu to Heilongtan.
The toll-free Chengjin Expressway in the east of Chengdu is long. It takes about half an hour to drive from central Chengdu to Jintang.
The expressway between Chengdu to Heilongtan (Chengdu section), going to the south of the city, is long. It is also toll-free and a journey from downtown Chengdu to Heilongtan will only take half an hour.
The extension of Guanghua Avenue, going towards the west of the city. It make the journey time from Chongzhou City to Sanhuan Road to less than half an hour.
The extension of Shawan Road going north is designed for travel at . After it is connected to the expressways Pixian–Dujiangyan and Pixian–Pengzhou, it will take only 30 minutes to go from Chengdu to Pengzhou.
Coach
There are many major intercity bus stations in Chengdu, and they serve different destinations.
Chadianzi (): Hongyuan, Jiuzhaigou, Rilong Town, Ruo Ergai, Songpan County, Wolong and Langzhong
Xinnanmen (: Daocheng, Emei Shan, Jiǔzhàigōu, Kangding, Garzê Tibetan Autonomous Prefecture, Ya'an and Leshan
Wuguiqiao (): Chongqing
Jinsha (): Qionglai, Pi County and Huayang () Chengdu East railway Station
Highways
National Highway G5 Beijing–Kunming
National Highway G42 Shanghai–Chengdu
National Highway G76 Xiamen–Chengdu
National Highway G93 Chengdu–Chongqing Ring
National Highway G4202 Chengdu Ring
Chengdu Metro
The Chengdu Metro officially opened on 1 October 2010. Line 1 runs from Shengxian Lake to Guangdu (south-north). Line 2 opened in September 2012. Line 3 opened in July 2016. Line 4 opened in December 2015. Line 10 connects to city center and Shuangliu International Airport. Future plans call for more than thirty lines. As of the end of June 2024, Chengdu has 558 km of metro lines in operation.
Bus
Bus transit is an important method of public transit in Chengdu. There are more than 400 bus lines in Chengdu with nearly 12,000 buses in total. In addition, the Chengdu BRT offers services on the Second Ring Road Elevated Road. Bus cards are available that permit free bus transfers for three hours.
River transport
Historically, Jinjiang River (also known as Nanhe River) was used for boat traffic in and out of Chengdu. To ensure that Chengdu's goods have access to Yangtze River efficiently, inland port cities of Yibin and Luzhou—both of which are reachable from Chengdu within hours by expressways—on the Yangtze have commenced large-scale port infrastructure development. As materials and equipment for the rebuilding of northern Sichuan are sent in from the East Coast to Sichuan, these ports will see significant increases in throughput.
Education and research
Wen Weng, administer of Chengdu in the Han dynasty, established the first local public school now named Shishi (literally a stone house) in the world. The school site has not changed for more than 2,000 years, which remains the site of today's Shishi High School. No. 7 High School and Shude High School are also two famous local public schools in Chengdu.
Chengdu is a leading scientific research city, one of the only two cities in the Western China region (alongside Xi'an), ranking in the top 25 cities worldwide by scientific research outputs. It is consistently ranked # 1 as the center of higher education and scientific research in Southwest China. The city is home to more than 58 universities, with the two reputable ones being Sichuan University and the University of Electronic Science and Technology of China, ranking 98 and 101-150 worldwide, respectively.
Higher education
Sichuan University (SCU) (Founded in 1896), including the West China Medical Center of Sichuan University (Founded in 1910)
Southwest Jiaotong University (Founded in 1896)
Southwestern University of Finance and Economics (Founded in 1925)
University of Electronic Science and Technology of China (Founded in 1956)
Chengdu University of Technology (Founded in 1956)
Sichuan Normal University (Founded in 1946)
Chengdu University of Traditional Chinese Medicine (Founded in 1956)
Chengdu Kinesiology University (Founded in 1942)
Southwest University for Nationalities (Founded in 1951)
Sichuan Conservatory of Music (Founded in 1939)
Xihua University (Founded in 1960)
Southwest Petroleum University (Founded in 1958)
Chengdu University of Information Technology (Founded in 1951)
Chengdu University (Founded in 1978)
Chengdu Medical College (Founded in 1947)
Note: Private institutions or institutions without full-time bachelor programs are not listed.
Consulates
The United States Consulate General at Chengdu opened on 16 October 1985. It was the first foreign consulate in west-central China since 1949. The United States Consulate General at Chengdu was closed on 27 July 2020, corresponding to the closure of Chinese Consulate-General, Houston. The Sri Lankan consulate in Chengdu opened in 2009, and was temporarily closed in 2016. Currently, 17 countries have consulates in Chengdu. The Philippines, India, Greece, Brazil and Argentina have been approved to open consulates in Chengdu.
Sports
Soccer
Soccer is a popular sport in Chengdu. Chengdu Tiancheng, Chengdu's soccer team, played in the 42,000-seat Chengdu Sports Stadium in the Chinese League One. The club was founded on 26 February 1996 and was formerly known as Chengdu Five Bulls named after their first sponsor, the Five Bulls Cigarette Company. English professional soccer club Sheffield United F.C., took over the club on 11 December 2005. The club was later promoted into the China Super League until they were embroiled in a match-fixing scandal in 2009. Punished with relegation the owners eventually sold their majority on 9 December 2010 to Hung Fu Enterprise Co., Ltd and Scarborough Development (China) Co., Ltd. On 23 May 2013 the Tiancheng Investment Group announced the acquisition of the club.
Currently, Chengdu Rongcheng F.C. plays in the Chinese Super League.
Longquanyi Stadium was one of the four venues which hosted the 2004 AFC Asian Cup. Chengdu, along with Shanghai, Hangzhou, Tianjin and Wuhan, hosted the 2007 FIFA Women's World Cup.
Tennis
Chengdu is the hometown of Grand Slam champions Zheng Jie and Yan Zi, who won the women's double championships at both the Australian Open and Wimbledon in 2006, and Li Na who won the 2011 French Open and 2014 Australian Open, has led to increased interest in tennis in Chengdu. Over 700 standard tennis courts have been built in the city in the past 10 years (2006–2016), and the registered membership for the Chengdu Tennis Association have grown to over 10,000 from the original 2,000 in the 1980s.
Chengdu is now part of an elite group of cities to host an ATP (Association of Tennis Professionals) Champions Tour tournament, along with London, Zürich, São Paulo and Delray Beach. Chengdu Open, an ATP Championships Tour starting in 2009, have successfully invited star players including Pete Sampras, Marat Safin, Carlos Moya, Tomas Enqvist, and Mark Philippoussis.
Overwatch
Chengdu was represented in the Overwatch League by the Chengdu Hunters, the first major esports team to represent Chengdu. They played as part of the League's Pacific Division from 2019 until 2022.
League of Legends
Chengdu hosted the 2024 Mid-Season Invitational from 1 May to 19 May at the Chengdu Financial City Performing Arts Center. South Korean team Gen.G defeated home favorites Bilibili Gaming 3-1 in a rematch of their upper bracket final match. Prior to the 2024 League of Legends World Championship grand finals, it was also announced that Chengdu would also host the 2025 tournament Final.
Multi-sport events
Chengdu hosted the 2021 Summer World University Games, originally scheduled to take place from 8–19 August 2021, but the delayed Summer Olympics in Tokyo from 2020 to 2021 caused the proposed dates to be moved due to the COVID-19 pandemic. The games would eventually be delayed to 28 July8 August 2023 due to COVID-19 concerns. The city will also host the 2025 World Games.
Major sports venues
The Chengdu Sports Center is located in downtown Chengdu, covering and has 42,000 seats. As one of the landmarks of Chengdu, it is the first large multipurpose venue in Chengdu that can accommodate sports competitions, trainings, social activities, and performances. It is the home stadium of the Chengdu Blades, Chengdu's soccer team. The stadium hosted the 2007 FIFA Women's World Cup.
The Sichuan International Tennis Center, located away from Chengdu's Shuangliu International Airport, covers an area of . It is the largest tennis center in southwest China and the fourth tennis center in China meeting ATP competition standards, after Beijing, Shanghai and Nanjing. This center is equipped with 36 standard tennis courts and 11,000 seats. Since 2016, the Chengdu Open, an ATP Championship Tour tournament, is held here annually.
The Chengdu Goldenport Circuit is a motorsport racetrack that has hosted the A1 Grand Prix, Formula V6 Asia, China Formula 4 Championship and China GT Championship.
Twin towns and sister cities
Chengdu is twinned with:
Agra, Uttar Pradesh, India
Bengaluru, Karnataka, India
Bonn, North Rhine-Westphalia, Germany (10 September 2009)
Cebu City, Central Visayas, Philippines
Chiang Mai, Chiang Mai Province, Thailand
Daegu, South Korea (10 November 2015)
Fingal, Ireland
Flemish Brabant, Flanders, Belgium (27 May 2011)
Gimcheon, North Gyeongsang Province, South Korea
Haifa, Israel
Hamilton, New Zealand (6 May 2015)
Honolulu, Hawaii, United States (14 September 2011)
Horsens, East Jutland, Denmark
Maputo, Mozambique
Kandy, Central Province, Sri Lanka
Kathmandu, Nepal
Knoxville, Tennessee, United States
Kofu, Yamanashi, Japan (27 September 1984)
Lahore, Punjab, Pakistan
Linz, Upper Austria, Austria (1983)
Ljubljana, Slovenia (1981)
Łódź, Łódź Voivodeship, Poland (29 June 2015)
Lviv, Lviv Oblast, Ukraine (2014)
Maastricht, Limburg, Netherlands (13 September 2012)
Mechelen, Belgium (1993)
Medan, North Sumatra, Indonesia (2002)
Melbourne, Victoria, Australia
Montpellier, Languedoc-Roussillon, France (22 June 1981)
Nashville, Tennessee, United States
Palermo, Sicily, Italy
Perth, Western Australia, Australia (September 2012)
Phoenix, Arizona, United States
Sheffield, South Yorkshire, United Kingdom (23 March 2010)
Volgograd, Volgograd Oblast, Russia (27 May 2011)
Winnipeg, Manitoba, Canada (1988)
Zapopan, Jalisco, Mexico
Chengdu also has friendly relationships or partnerships with:
Adelaide, South Australia, Australia
Atlanta, Georgia, United States
Baku, Azerbaijan
Beyoğlu, Istanbul, Turkey
City of Gold Coast, Queensland, Australia
Dalarna, Sweden
Fez, Morocco
Milan, Lombardy, Italy
Saint Petersburg, Russia
Tallinn, Estonia
Valencia, Spain
Notable people
Tang Danhong, filmmaker and poet
Yang Hongying, (born 1962), best-selling author of children's fiction books
Tao Jiali (born 1987), fighter pilot in the People's Liberation Army Air Force
Muni He/Lily He (born 1999), golfer
Shen Xiaoting (Born 1999), singer (Kep1er)
Li Yifeng (born 1987), male actor
Jason Zhang (born 1982), pop singer
Li Yuchun (born 1984), singer and actress
Jane Zhang (born 1984), singer and songwriter
Gong Jun (born 1992), actor
Zhao Lusi (born 1998), actress and singer
Guo Feng (born 1962), songwriter and singer
Xu Deqing (born 1963), general in the People's Liberation Army (PLA) serving as political commissar of the Central Theater Command since January 2022.
Zhi-Ming Ma (born 1948), mathematics professor of Chinese Academy of Sciences, former Vice Chairman of the Executive Committee for International Mathematical Union
Huajian Gao (born 1963), Chinese-American mechanician widely known for his contributions to the field of solid mechanics
See also
List of cities in China by population
List of current and former capitals of subdivisions of China
List of twin towns and sister cities in China
Notes
References
Bibliography
Cheung, Raymond. OSPREY AIRCRAFT OF THE ACES 126: Aces of the Republic of China Air Force. Oxford: Bloomsbury Publishing Plc, 2015. .
Mayhew, Bradley; Miller, Korina; English, Alex, South-West China, Lonely Planet Publications, 1998 (2nd edition 2002). Cf. p. 444 for its article on Chengdu.
Quian, Jack, Chengdu: A City of Paradise, 2006
Further reading
Ling Zhu, "Chengdu, the city of spice and tea" , China Daily, Government of China, Friday, 22 December 2006
Anna Zhang, "City Profile: Chengdu – Land of Abundance," Shanghai Business Review, July 2012.
Stapleton, Kristin. Civilizing Chengdu.
Stapleton, Kristin. Fact in Fiction
External links
Official website of the Chengdu Government
Official website of the Chengdu Government
310s BC establishments
316 BC
National forest cities in China
Populated places established in the 4th century BC
Provincial capitals in China
Webarchive template wayback links
Eutrophication
Prefecture-level divisions of Sichuan
Cities in Sichuan
Sub-provincial cities in the People's Republic of China | Chengdu | Chemistry,Environmental_science | 16,416 |
49,209,954 | https://en.wikipedia.org/wiki/Oil%20constant | The term crude oil constant (Erdölkonstante in German) has been used as an inside joke and pun in the German petroleum industry, pointing out that the reserves-to-production ratio has been observed as roughly constant in the past decades, whereas oil constant (Ölkonstante in German) is a term describing various material properties of (vegetable and mineral) oils.
Reasons for reserve expansion
The so-called crude oil constant refers to the approximately constant estimate of available petroleum reserves to production ratio R/P. The estimated duration until the available petroleum reserves are depleted at current production has remained around 40 years since the late 80s. Prewar and immediately postwar estimates were sometimes lower, in 1919 as low as 9 years (USA) and in 1948 around 20 years (world) and rose up to 35 years until the 1970s. However, since then the duration value of static production T=R/P has been rather constant for decades despite rising oil consumption.
Price elasticity of reserves
One factor contributing to the apparent constancy of the R/P ratio is a neglect or misunderstanding of the fact that the term "proven reserves" does not refer to some absolute quantity of remaining oil that is thought to exist, but rather to the quantity of oil that can be economically extracted given the current price of oil and current oil-extraction technologies. Thus, either an increase in the price of oil or improvements in oil-extraction technologies can lead to an increase in the estimate of "proven reserves" since more-expensive-to-mine deposits such as tight oil become economically viable at a higher oil price, and because newer or more expensive enhanced oil recovery processes such as gas injection, steam injection, and hydraulic fracturing allow continued extraction of oil from fields that would have been considered worth to abandon at a lower price or using older technologies. Thus, it is possible for the "proven reserves of oil" (i.e., economically extractable reserves of oil) to keep pace with or even pull ahead of oil consumption at the current rate.
Unconventional oil
On the other hand, the reserves to production ratio is only one mathematical indicator for the geological inventory. More important than the size of the tank is the production rate (e.g. the size of the spigot of a barrel), and with many capital-intensive technologies for extracting oil from non-conventional sources, also the flow rate is getting smaller. A large expansion of global reserves took place in the 2000s, when Athabasca oil sands (Canada) and the heavy oil of the Orinoco Belt (Venezuela) were reclassified from (physically in place) ressource to (producible) reserve. While the oil reserves are sizeable and in the same range as the reserves of Saudi Arabia, oil production is growing slowly in Canada and declining in Venezuela.
OPEC quota wars
Another contributing factor for the steady P/R-ratio is the large expansion of OPEC reserves, that were booked in the years around 1988. The OPEC quota system had been amended, allowing a production which relates to the reported reserves. Within a few years, OPEC members raised their reserves on paper without reporting any major new discoveries.
SEC reporting rules
Oil companies which were listed at US stock exchanges or elsewhere are obliged to report their reserves on the principle of carefulness. This led to the effect that a new discovery was first reported by its lowest estimate (P90 = high confidence). Later, during production when the reservoir data became more detailed, the most likely estimate (P50) was reported but without backdating this reserve expansion to the year of the discovery. Enhanded oil recovery techniques made it possible to produce the P10 value (10% probability), but again the backdating was forgotten and it seemed as if new discoveries have been made.
Analogous use
A similar pun has been used about the feasibility of fusion power: Since the 1950s, feasible technological means of using fusion for electricity production have constantly been predicted as being 30–40 years ahead, so the "fusion constant" exhibits a similar range to the "oil constant".
References
Petroleum
Pseudoscience
Fusion power | Oil constant | Physics,Chemistry | 837 |
54,021,788 | https://en.wikipedia.org/wiki/Ole%20Holger%20Petersen | Ole Holger Petersen (born 3 March 1943) is a Danish-born research professor at Cardiff University where he studies physiology, especially calcium signalling and the pancreas. He was born in 1943 in Copenhagen, the first son of Joergen Petersen, an officer in the Danish navy, and Elisabeth née Klein, a pianist.
Prior to this he was Symers Professor of Physiology at the University of Dundee, and then George Holt Professor of Physiology at the University of Liverpool.
Petersen was elected a member of the Academia Europaea in 1988. He was elected a Fellow of the Royal Society (FRS) in 2000 "for his major contributions to the understanding of the cell physiology of calcium signalling", and appointed a Commander of the Order of the British Empire (CBE) in the 2008 New Year Honours, "for services to Science".
Petersen was elected a Fellow of the Learned Society of Wales in 2011. He is also a Fellow of the Academy of Medical Sciences (FMedSci).
References
External links
1943 births
Academics of Cardiff University
University of Copenhagen alumni
Commanders of the Order of the British Empire
Fellows of the Academy of Medical Sciences (United Kingdom)
Fellows of the Royal Society
Living people
Members of Academia Europaea
Presidents of The Physiological Society
Fellows of the Learned Society of Wales
Danish emigrants to the United Kingdom
Naturalised citizens of the United Kingdom | Ole Holger Petersen | Chemistry | 271 |
7,604,357 | https://en.wikipedia.org/wiki/Methylidyne%20radical | Methylidyne, or (unsubstituted) carbyne, is an organic compound whose molecule consists of a single hydrogen atom bonded to a carbon atom. It is the parent compound of the carbynes, which can be seen as obtained from it by substitution of other functional groups for the hydrogen.
The carbon atom is left with either one or three unpaired electrons (unsatisfied valence bonds), depending on the molecule's excitation state; making it a radical. Accordingly, the chemical formula can be CH• or CH3• (also written as ⫶CH); each dot representing an unpaired electron. The corresponding systematic names are methylylidene or hydridocarbon(•), and methanetriyl or hydridocarbon(3•). However, the formula is often written simply as CH.
Methylidyne is a highly reactive gas, that is quickly destroyed in ordinary conditions but is abundant in the interstellar medium (and was one of the first molecules to be detected there).
Nomenclature
The trivial name carbyne is the preferred IUPAC name.
Following the substitutive nomenclature, the molecule is viewed as methane with three hydrogen atoms removed, yielding the systematic name "methylidyne".
Following the additive nomenclature, the molecule is viewed as a hydrogen atom bonded to a carbon atom, yielding the name "hydridocarbon".
By default, these names pay no regard to the excitation state of the molecule. When that attribute is considered, the states with one unpaired electron are named "methylylidene" or "hydridocarbon(•)", whereas the excited states with three unpaired electrons are named "methanetriyl" or "hydridocarbon(3•)".
Bonding
As an odd-electron species, CH is a radical. The ground state is a doublet (X2Π). The first two excited states are a quartet (with three unpaired electrons) (a4Σ−) and a doublet (A2Δ). The quartet lies at 71 kJ/mol above the ground state.
Reactions of the doublet radical with non-radical species involves insertion or addition:
[CH]•(X2Π) + → H• + CO (major) or •
whereas reactions of the quartet radical generally involves only abstraction:
[CH]3•(a4Σ−) + → + [HO]•
Methylidyne can bind to metal atoms as tridentate ligand in coordination complexes. An example is methylidynetricobaltnonacarbonyl .
Occurrence and reactivity
Fischer–Tropsch intermediate
Methylidyne-like species are implied intermediates in the Fischer–Tropsch process, the hydrogenation of CO to produce hydrocarbons. Methylidyne entities are assumed to bond to the catalyst's surface. A hypothetical sequence is:
MnCO + H2 → MnCOH
MnCOH + H2 → MnCH + H2O
MnCH + H2 → MnCH2
The MnCH intermediate has a tridentate methylidine ligand. The methylene ligand (H2C) is then poised couple to CO or to another methylene, thereby growing the C–C chain.
Amphotericity
The methylylidyne group can exhibit both Lewis acidic and Lewis basic character. Such behavior is only of theoretical interest since it is not possible to produce methylidyne.
In interstellar space
In October 2016, astronomers reported that the methylidyne radical ⫶CH, the carbon-hydrogen positive ion :CH+, and the carbon ion ⫶C+ are the result of ultraviolet light from stars, rather than in other ways, such as the result of turbulent events related to supernovas and young stars, as thought earlier.
Preparation
Methylidyne can be prepared from bromoform.
See also
Methylene group
Methylene bridge
References
Organometallic chemistry
Free radicals | Methylidyne radical | Chemistry,Biology | 815 |
4,231,780 | https://en.wikipedia.org/wiki/Methacrylate | Methacrylates are derivatives of methacrylic acid. These derivatives are mainly used to make poly(methyl methacrylate) and related polymers.
Monomers
Methyl methacrylate
Ethyl methacrylate
Butyl methacrylate
Hydroxyethyl methacrylate
Glycidyl methacrylate
Carboxylate anions
Monomers
Methacrylate esters | Methacrylate | Chemistry,Materials_science | 93 |
24,318,538 | https://en.wikipedia.org/wiki/C21H24O10 | {{DISPLAYTITLE:C21H24O10}}
The molecular formula C21H24O10 (molar mass: 436.41 g/mol, exact mass: 436.136947 u) may refer to:
Nothofagin, a C-linked phloretin glucoside
Phlorizin, an O-linked phloretin glucoside
Molecular formulas | C21H24O10 | Physics,Chemistry | 88 |
16,286,691 | https://en.wikipedia.org/wiki/AU-rich%20element | Adenylate-uridylate-rich elements (AU-rich elements; AREs) are found in the 3' untranslated region (UTR) of many messenger RNAs (mRNAs) that code for proto-oncogenes, nuclear transcription factors, and cytokines. AREs are one of the most common determinants of RNA stability in mammalian cells. The function of AREs was originally discovered by Shaw and Kamen in 1986.
AREs are defined as a region with frequent adenine and uridine bases in a mRNA. They usually target the mRNA for rapid degradation.
ARE-directed mRNA degradation is influenced by many exogenous factors, including phorbol esters, calcium ionophores, cytokines, and transcription inhibitors. These observations suggest that AREs play a critical role in the regulation of gene transcription during cell growth and differentiation, and the immune response. As evidence of its critical role, deletion of the AREs from the 3'UTR in either the TNF gene or GM-CSF gene in mice leads to over expression of each respective gene product, causing dramatic disease phenotypes.
AREs have been divided into three classes with different sequences. The best characterised adenylate uridylate (AU)-rich Elements have a core sequence of AUUUA within U-rich sequences (for example WWWU(AUUUA)UUUW where W is A or U). This lies within a 50–150 base sequence, repeats of the core AUUUA element are often required for function.
A number of different proteins (e.g. HuA, HuB, HuC, HuD, HuR) bind to these elements and stabilise the mRNA while others (AUF1, TTP, BRF1, TIA-1, TIAR, and KSRP) destabilise the mRNA, miRNAs may also bind to some of them. For example, the human microRNA, miR16, contains an UAAAUAUU sequence that is complementary to the ARE sequence and appears to be required for ARE-mRNA turnover. HuD (also called ELAVL4) binds to AREs and increases the half-life of ARE-bearing mRNAs in neurons during brain development and plasticity.
AREsite—a database for ARE containing genes—has recently been developed with the aim to provide detailed bioinformatic characterization of AU-rich elements.
Classifications
Class I ARE elements, like the c-fos gene, have dispersed AUUUA motifs within or near U-rich regions.
Class II elements, like the GM-CSF gene, have overlapping AUUUA motifs within or near U-rich regions.
Class III elements, like the c-jun gene, are a much less well-defined class—they have a U-rich region but no AUUUA repeats.
No real ARE consensus sequence has been determined yet, and these categories are based neither on the same biological functions, nor on the homologous proteins.
Mechanism of ARE-mediated decay
AREs are recognized by RNA binding proteins such as tristetraprolin (TTP), AUF1, and Hu Antigen R (HuR). Although the exact mechanism is not very well understood, recent publications have attempted to propose the action of some of these proteins. AUF1, also known as hnRNP D, binds AREs through RNA recognition motifs (RRMs). AUF1 is also known to interact with the translation initiation factor eIF4G and with poly(A)-binding protein, indicating that AUF1 senses the translational status of mRNA and decays accordingly through the excision of the poly(A) tail.
TTP's (ZFP36's) expression is rapidly induced by insulin. Immunoprecipitation experiments have shown that TTP co-precipitates with an exosome, suggesting that it helps recruit exosomes to the mRNA containing AREs. Alternatively, HuR proteins have a stabilizing effect—their binding to AREs increases the half-life of mRNAs. Similar to other RNA-binding proteins, this class of proteins contain three RRMs, two of which are specific to ARE elements. A likely mechanism for HuR action relies on the idea that these proteins compete with other proteins that normally have a destabilizing effect on mRNAs. HuRs are involved in genotoxic response—they accumulate in the cytoplasm in response to UV exposure and stabilize mRNAs that encode proteins involved in DNA repair.
Disease
Problems with mRNA stability have been identified in viral genomes, cancer cells, and various diseases. Research shows that many of these problems arise because of faulty ARE function. Deficiency of the ZFP36 family show that ZFP36 ARE binding proteins are critical regulators of T cell homeostasis and autoimmunity. Some of these problems have been listed below:
The c-fos gene produces a transcription factor that is activated in several cancers, the ARE present in c-fos plays a role in its post-transcriptional regulation.
c-myc gene, also responsible for producing transcription factors found in several cancers, the ARE present in c-myc plays a role in its post-transcriptional regulation.
The Cox-2 gene catalyses the production of prostaglandins—it overexpresses in several cancers, and is stabilized by the binding of CUGBP2 RNA-binding protein to ARE
References
External links
Review of original publication discovering AU-rich elements
Pillars link to original 1986 Cell publication discovering AU-rich elements
mRNA Translational blockade by AU-rich elements
Brief introduction to mRNA regulatory elements
ARED: AU-rich element database
Transterm page for AU-Rich Element
AREsite: An online resource for the analysis of AREs
RNA
Gene expression
Cis-regulatory RNA elements | AU-rich element | Chemistry,Biology | 1,189 |
39,847,338 | https://en.wikipedia.org/wiki/Nettenchelys%20taylori | Nettenchelys taylori is an eel in the family Nettastomatidae (duckbill/witch eels). It was described by Alfred William Alcock in 1898. It is a marine, deep-water dwelling eel which is known from a single specimen from India, in the western Indian Ocean. From the specimen it is known to dwell at a depth of , and to reach a total length of .
The species epithet "taylori" refers to Commander A. Dundas Taylor of the Indian Navy, credited by the author as playing a notable role in the revival of the Marine Survey of India in 1874.
References
taylori
Fish described in 1898
Species known from a single specimen | Nettenchelys taylori | Biology | 139 |
12,151,116 | https://en.wikipedia.org/wiki/C-myc%20mRNA | C-myc mRNA is a type of mRNA that serves as a template for the MYC protein which is implicated in the rapid growth of cancer cells. This mRNA is a topic of ongoing research to investigate the viability of preventing cancer growth by cleaving or degrading the c-myc mRNA.
See also
C-myc
References
RNA
Molecular biology | C-myc mRNA | Chemistry,Biology | 75 |
68,889,599 | https://en.wikipedia.org/wiki/Jedi2 | Jedi2 is a chemical compound which acts as an agonist for the mechanosensitive ion channel PIEZO1, and is used in research into the function of touch perception.
See also
Yoda1 and Jedi1
References
Furans
Thiophenes | Jedi2 | Chemistry | 54 |
42,362,242 | https://en.wikipedia.org/wiki/Dwight%20C.%20Olson | Dwight C. Olson was the founder of Data Securities International.
Education
Olson received a bachelor's degree in mathematics and teaching credentials from Augsburg University in Minneapolis, Minnesota.
Accomplishments
Olson began his career in the research and development of supercomputers, parallel processing systems and related application architectures in the 1960s and 1970s.
Olsen founded Data Securities International in 1982, which pioneered technology escrow and is known as the father of technology escrow.
Olson is a former chairman of the Board of Governors of Certified Licensing Professionals, Inc (CLP), a former President of the Licensing Executives Society, USA and Canada, and he has served as chair of LESI IP Valuation committee.
Olson was an associate member of the American Bar Association's Electronic Commerce Law and Information Security Committee working on the ABA's Digital Signature Guidelines.
Olson is the author of Northern Lights: the beauty of the Forgotten Scandinavian Enamel Artisans, published in 2019 ().
Olson is the author of The Long Journey to Software Valuation, published in 2020 ().
References
http://trumanenamels.com/bioDCO.htm
People in information technology
Living people
Year of birth missing (living people) | Dwight C. Olson | Technology | 238 |
26,618,019 | https://en.wikipedia.org/wiki/HD%20212771%20b | HD 212771 b is an extrasolar planet orbiting the G-type star HD 212771 approximately 364 light years away in the constellation Aquarius.
Nomenclature
HD 212771 b is named Victoriapeak. The name was selected in the NameExoWorlds campaign by Hong Kong, during the 100th anniversary of the IAU. It is named after the Victoria Peak, the highest point on Hong Kong Island. The host star HD 212771 is named Lionrock, after the Lion Rock.
Properties
Orbit
HD 212771 b's orbit period and distance are similar to Earth's, with the values being 380 days and 1.19 AU respectively. It orbits in a nearly perfect circular orbit compared to long period gas giants.
Characteristics
Due to the unknown orbital parameters, the planets true mass is not known, with a minimum of 2.39 times Jupiter's mass. HD 212771 b's radius is unknown, so NASA's Eyes on Exoplanets gives an estimate of 1.18 times the radius.
See also
HD 4313 b
HD 181342 b
HD 206610 b
HD 180902 b
HD 136418 b
References
External links
Exoplanets discovered in 2009
Exoplanets detected by radial velocity
Aquarius (constellation)
Giant planets
Exoplanets with proper names | HD 212771 b | Astronomy | 277 |
11,793,494 | https://en.wikipedia.org/wiki/Gloeosporium%20theae-sinensis | Gloeosporium theae-sinensis (syn. Colletotrichum theae-sinensis) is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Dermateaceae
Fungal plant pathogens and diseases
Fungus species | Gloeosporium theae-sinensis | Biology | 54 |
66,192,711 | https://en.wikipedia.org/wiki/GosNIIOKhT | The State Research Institute of Organic Chemistry and Technology () (GosNIIOKhT) is a Russian research institute engaged in the development of chemical technologies for use in the national economy and the production of relevant goods and products.
History
GosNIIOKhT was founded in 1924, during the time of the Soviet Union, to conduct research work in organic synthesis and to be for the Soviet state the umbrella organization for it, below which were arrayed a number of satellite institutes.
From the early 1930s, the research institute was engaged in the development of chemical weapons. Significant numbers of scientists were also assigned to develop anti-crop and anti-animal agents.
GosNIIOKhT employed approximately 6,000 people by the dissolution of the Soviet Union. The employees worked in Novocheboksarsk on nerve agent production, in Volgograd on nerve agent production, in Dzerzinsk on blister agent production, in Shikhany on testing, and in Nukus, Uzbekistan on testing.
The Yeltsin government alarmed the international community by stating that it could not afford to keep the GosNIIOKhT facilities open or personnel employed, as that would mean starving scientists would have incentive to work for nefarious organizations.
By December 1999 the International Science and Technology Center had borne small fruit. In the opinion of one writer, "permitting the ISTC and the other grant programs to sponsor projects that work with Western commercial companies to retool some equipment and kick off the manufacturing of consumer products at these facilities. An advantage to lifting the congressional ban on defense conversion is that the Western commercial partners would have a frequent presence on site—an arrangement likely to foil efforts to produce warfare agents covertly at these facilities. Such an outcome
is far preferable to allowing the skilled labor at these facilities to become increasingly destitute and even desperate... Entire segments of poison gas experts have no contact with the [ISTC] grant programs, especially those within the design bureaus that have specialized skills in the aerosolization of agents and their weaponization."
Currently, its activities include the production of chemical weapons and other hazardous materials. Other areas of work include the development and production of drugs, toxicological research, preclinical testing, chemical technology, and environmental safety.
The Navalny affair
On 15 October 2020, European Union sanctions were imposed on the institute in connection with the poisoning of politician Alexei Navalny. The Council of the European Union's grounds for designation states
US sanctions
On 21 March 2021, invoking its authorities under the Countering America’s Adversaries Through Sanctions Act (CAATSA) Section 231, the United States Department of State added GosNIIOKhT to its List of Specified Persons as persons that are part of, or operate for or on behalf of, the defense or intelligence sectors of the Government of the Russian Federation. The Department describes GosNIIOKhT as "a Russian institute with a longstanding role in researching and developing chemical weapons, and GosNIIOKhT developed Russia’s Novichok chemical weapons. Since 2016, GosNIIOKhT has expanded its research, development, testing, and evaluation capabilities."
In addition, GosNIIOKhT was designated under the authority of the International Emergency Economic Powers Act and , "Blocking Property of Weapons of Mass Destruction Proliferators and Their Supporters."
References
Soviet chemical weapons program
Novichok agents
Research institutes in the Soviet Union
Chemical research institutes
Research institutes established in 1924
1924 establishments in the Soviet Union | GosNIIOKhT | Chemistry | 719 |
5,508,956 | https://en.wikipedia.org/wiki/Ishango%20bone | The Ishango bone, discovered at the "Fisherman Settlement" of Ishango in the Democratic Republic of the Congo, is a bone tool and possible mathematical device that dates to the Upper Paleolithic era. The curved bone is dark brown in color, about 10 centimeters in length, and features a sharp piece of quartz affixed to one end, perhaps for engraving. Because the bone has been narrowed, scraped, polished, and engraved to a certain extent, it is no longer possible to determine what animal the bone belonged to, although it is assumed to have been a mammal.
The ordered engravings have led many to speculate the meaning behind these marks, including interpretations like mathematical significance or astrological relevance. It is thought by some to be a tally stick, as it features a series of what has been interpreted as tally marks carved in three columns running the length of the tool, though it has also been suggested that the scratches might have been to create a better grip on the handle or for some other non-mathematical reason. Others argue that the marks on the object are non-random and that it was likely a kind of counting tool and used to perform simple mathematical procedures. Other speculations include the engravings on the bone serving as a lunar calendar. Dating to 20,000 years before present, it has been described as 'the oldest mathematical tool of humankind', though older engraved bones are also known, such as the approximately 26,000 year-old 'Wolf Bone' from Dolni Vestonice in the Czech Republic, and the approximately 40,000-year-old Lebombo bone from southern Africa.
History
Archaeological discovery
The Ishango bone was found in 1950 by Belgian Jean de Heinzelin de Braucourt while exploring what was then the Belgian Congo. It was discovered in the area of Ishango near the Semliki River. Lake Edward empties into the Semliki which forms part of the headwaters of the Nile River (now on the border between modern-day Uganda and D.R. Congo). Some archaeologists believe the prior inhabitants of Ishango were a "pre-sapiens species". However, the most recent inhabitants, who gave the area its name, have no immediate connections with the primary settlement, which was "buried in a volcanic eruption".
On an excavation, de Heinzelin discovered a bone about the "size of a pencil" amongst human remains and many stone tools in a small community that fished and gathered in this area of Africa. Professor de Heinzelin brought the Ishango bone to Belgium, where it was stored in the treasure room of the Royal Belgian Institute of Natural Sciences in Brussels. Several molds and copies were created from the petrified bone in order to preserve the delicate nature of the fragile artifact while being exported. A written request to the museum was required to see the artifact, as it was no longer on display for the public eye.
Dating
The artifact was first estimated to have originated between 9,000 BCE and 6,500 BCE, with numerous other analyses debating the bone to be as old as 44,000 years. However, the dating of the site where it was discovered was re-evaluated, and it is now believed to be about 20,000 years old (dating from between 18,000 BCE and 20,000 BCE). The dating of this bone is widely debated in the archaeological community as the ratio of Carbon-14 isotopes was upset by nearby volcanic activity.
Interpretations
Mathematical
The 168 etchings on the bone are ordered in three parallel columns along the length of the bone, each marking with a varying orientation and length. The first column, or central column along the most curved side of the bone, is referred to as the M column, from the French word (middle). The left and right columns are respectively referred to as G and D, or (left) and (right) in French. The parallel markings have led to various tantalizing hypotheses, such as that the implement indicates an understanding of decimals or prime numbers. Though these propositions have been questioned, it is considered likely by many scholars that the tool was used for mathematical purposes, perhaps including simple mathematical procedures or to construct a numeral system.
Discoverer of the Ishango bone, de Heinzelin, suggested that the bone was evidence of knowledge of simple arithmetic, or at least that the markings were "deliberately planned". He based his interpretation on archaeological evidence, comparing "Ishango harpoon heads to those found in northern Sudan and ancient Egypt". This comparison led to the suggestion of a link between arithmetic processes conducted at Ishango with the "commencement of mathematics in ancient Egypt." The third column has been interpreted as a "table of prime numbers", as column G appears to illustrate prime numbers between 10 and 20, but this may be a coincidence. Historian of mathematics Peter S. Rudman argues that prime numbers were probably not understood until the early Greek period of about 500 BCE, and were dependent on the concept of division, which he dates to no earlier than 10,000 BCE.
More recently, mathematicians Dirk Huylebrouck and Vladimir Pletser have proposed that the Ishango bone is a counting tool using the base 12 and sub-bases 3 and 4, and involving simple multiplication, somewhat comparable to a primitive slide rule. However, they have concluded that there is not sufficient evidence to confirm an understanding of prime numbers during this time period.
Anthropologist Caleb Everett has also provided insight into interpretations of the bone, explaining that "the quantities evident in the groupings of marks are not random", and are likely evidence of prehistoric numerals. Everett suggests that the first column may reflect some "doubling pattern" and that the tool may have been used for counting and multiplication and also possibly as a "numeric reference table".
Astronomical
Alexander Marshack, an archaeologist from Harvard University, speculated that the Ishango bone represents numeric notation of a six-month lunar calendar after conducting a "detailed microscopic examination" of the bone. This idea arose from the fact that the markings on the first two rows adds up to 60, corresponding with two lunar months, and the sum of the number of carvings on the last row being 48, or a month and a half. Marshack generated a diagram comparing the different sizes and phases of the Moon with the notches of the Ishango bone. There is some circumstantial evidence to support this alternate hypothesis, being that present day African societies utilize bones, strings, and other devices as calendars. However, critics in the field of archaeology have concluded that Marshack's interpretation is flawed, describing that his analysis of the Ishango bone confines itself to a simple search for a pattern, rather than an actual test of his hypothesis.
This has also led Claudia Zaslavsky to suggest that the creator of the tool may have been a woman, tracking the lunar phase in relation to the menstrual cycle.
Other explanations
Mathematician Olivier Keller warns against the urge to project modern culture's perception of numbers onto the Ishango bone. Keller explains that this practice encourages observers to negate and possibly ignore alternative symbolic materials, those which are present in a range of media (on human remains, stones and cave art) from the Upper Paleolithic era and beyond which also deserve equitable investigation.
Dirk Huylebrouck, in a review of the research on the object, favors the idea that the Ishango bone had some advanced mathematical use, stating that "whatever the interpretation, the patterns surely show the bone was more than a simple tally stick." He also remarks that "to credit the computational and astronomical reading simultaneously would be far-fetched", quoting mathematician George Joseph, who stated that "a single bone may well collapse under the heavy weight of conjectures piled onto it." Similarly, George Joseph, in "The Crest of the Peacock: Non-European Roots of Mathematics" also stated that the Ishango bone was "more than a simple tally." Moreover, he states that "certain underlying numerical patterns may be observed within each of the rows marked." But, regarding various speculative theories of its exact mathematical use, concluded that several are plausible but uncertain.
See also
Lebombo bone
History of mathematics
Paleolithic tally sticks
References
Further reading
O. Keller, "The fables of Ishango, or the irresistible temptation of mathematical fiction"
V. Pletser, D. Huylebrouck, "Contradictions and narrowness of views in "The fables of Ishango, or the irresistible temptation of mathematical fiction", answers and updates"
Archaeological discoveries in Africa
History of Africa
History of mathematics
Mathematical tools
Bone carvings
Upper Paleolithic
1950 archaeological discoveries | Ishango bone | Mathematics,Technology | 1,772 |
1,539,785 | https://en.wikipedia.org/wiki/Dark%20matter%20halo | In modern models of physical cosmology, a dark matter halo is a basic unit of cosmological structure. It is a hypothetical region that has decoupled from cosmic expansion and contains gravitationally bound matter.
A single dark matter halo may contain multiple virialized clumps of dark matter bound together by gravity, known as subhalos.
Modern cosmological models, such as ΛCDM, propose that dark matter halos and subhalos may contain galaxies. The dark matter halo of a galaxy envelops the galactic disc and extends well beyond the edge of the visible galaxy. Thought to consist of dark matter, halos have not been observed directly. Their existence is inferred through observations of their effects on the motions of stars and gas in galaxies and gravitational lensing. Dark matter halos play a key role in current models of galaxy formation and evolution. Theories that attempt to explain the nature of dark matter halos with varying degrees of success include cold dark matter (CDM), warm dark matter, and massive compact halo objects (MACHOs).
Rotation curves as evidence of a dark matter halo
The presence of dark matter (DM) in the halo is inferred from its gravitational effect on a spiral galaxy's rotation curve. Without large amounts of mass throughout the (roughly spherical) halo, the rotational velocity of the galaxy would decrease at large distances from the galactic center, just as the orbital speeds of the outer planets decrease with distance from the Sun. However, observations of spiral galaxies, particularly radio observations of line emission from neutral atomic hydrogen (known, in astronomical parlance, as 21 cm Hydrogen line, H one, and H I line), show that the rotation curve of most spiral galaxies flattens out, meaning that rotational velocities do not decrease with distance from the galactic center. The absence of any visible matter to account for these observations implies either that unobserved (dark) matter, first proposed by Ken Freeman in 1970, exist, or that the theory of motion under gravity (general relativity) is incomplete. Freeman noticed that the expected decline in velocity was not present in NGC 300 nor M33, and considered an undetected mass to explain it. The DM Hypothesis has been reinforced by several studies.
Formation and structure of dark matter halos
The formation of dark matter halos is believed to have played a major role in the early formation of galaxies. During initial galactic formation, the temperature of the baryonic matter should have still been much too high for it to form gravitationally self-bound objects, thus requiring the prior formation of dark matter structure to add additional gravitational interactions. The current hypothesis for this is based on cold dark matter (CDM) and its formation into structure early in the universe.
The hypothesis for CDM structure formation begins with density perturbations in the Universe that grow linearly until they reach a critical density, after which they would stop expanding and collapse to form gravitationally bound dark matter halos. The spherical collapse framework analytically models the formation and growth of such halos. These halos would continue to grow in mass (and size), either through accretion of material from their immediate neighborhood, or by merging with other halos. Numerical simulations of CDM structure formation have been found to proceed as follows: A small volume with small perturbations initially expands with the expansion of the Universe. As time proceeds, small-scale perturbations grow and collapse to form small halos. At a later stage, these small halos merge to form a single virialized dark matter halo with an ellipsoidal shape, which reveals some substructure in the form of dark matter sub-halos.
The use of CDM overcomes issues associated with the normal baryonic matter because it removes most of the thermal and radiative pressures that were preventing the collapse of the baryonic matter. The fact that the dark matter is cold compared to the baryonic matter allows the DM to form these initial, gravitationally bound clumps. Once these subhalos formed, their gravitational interaction with baryonic matter is enough to overcome the thermal energy, and allow it to collapse into the first stars and galaxies. Simulations of this early galaxy formation matches the structure observed by galactic surveys as well as observation of the Cosmic Microwave Background.
Density profiles
A commonly used model for galactic dark matter halos is the pseudo-isothermal halo:
where denotes the finite central density and the core radius. This provides a good fit to most rotation curve data. However, it cannot be a complete description, as the enclosed mass fails to converge to a finite value as the radius tends to infinity. The isothermal model is, at best, an approximation. Many effects may cause deviations from the profile predicted by this simple model. For example, (i) collapse may never reach an equilibrium state in the outer region of a dark matter halo, (ii) non-radial motion may be important, and (iii) mergers associated with the (hierarchical) formation of a halo may render the spherical-collapse model invalid.
Numerical simulations of structure formation in an expanding universe lead to the empirical NFW (Navarro–Frenk–White) profile:
where is a scale radius, is a characteristic (dimensionless) density, and = is the critical density for closure. The NFW profile is called 'universal' because it works for a large variety of halo masses, spanning four orders of magnitude, from individual galaxies to the halos of galaxy clusters. This profile has a finite gravitational potential even though the integrated mass still diverges logarithmically. It has become conventional to refer to the mass of a halo at a fiducial point that encloses an overdensity 200 times greater than the critical density of the universe, though mathematically the profile extends beyond this notational point. It was later deduced that the density profile depends on the environment, with the NFW appropriate only for isolated halos. NFW halos generally provide a worse description of galaxy data than does the pseudo-isothermal profile, leading to the cuspy halo problem.
Higher resolution computer simulations are better described by the Einasto profile:
where r is the spatial (i.e., not projected) radius. The term is a function of n such that is the density at the radius that defines a volume containing half of the total mass. While the addition of a third parameter provides a slightly improved description of the results from numerical simulations, it is not observationally distinguishable from the 2 parameter NFW halo, and does nothing to alleviate the cuspy halo problem.
Shape
The collapse of overdensities in the cosmic density field is generally aspherical. So, there is no reason to expect the resulting halos to be spherical. Even the earliest simulations of structure formation in a CDM universe emphasized that the halos are substantially flattened. Subsequent work has shown that halo equidensity surfaces can be described by ellipsoids characterized by the lengths of their axes.
Because of uncertainties in both the data and the model predictions, it is still unclear whether the halo shapes inferred from observations are consistent with the predictions of ΛCDM cosmology.
Halo substructure
Up until the end of the 1990s, numerical simulations of halo formation revealed little substructure. With increasing computing power and better algorithms, it became possible to use greater numbers of particles and obtain better resolution. Substantial amounts of substructure are now expected. When a small halo merges with a significantly larger halo it becomes a subhalo orbiting within the potential well of its host. As it orbits, it is subjected to strong tidal forces from the host, which cause it to lose mass. In addition the orbit itself evolves as the subhalo is subjected to dynamical friction which causes it to lose energy and angular momentum to the dark matter particles of its host. Whether a subhalo survives as a self-bound entity depends on its mass, density profile, and its orbit.
Angular momentum
As originally pointed out by Hoyle and first demonstrated using numerical simulations by Efstathiou & Jones, asymmetric collapse in an expanding universe produces objects with significant angular momentum.
Numerical simulations have shown that the spin parameter distribution for halos formed by dissipation-less hierarchical clustering is well fit by a log-normal distribution, the median and width of which depend only weakly on halo mass, redshift, and cosmology:
with and . At all halo masses, there is a marked tendency for halos with higher spin to be in denser regions and thus to be more strongly clustered.
Milky Way dark matter halo
The visible disk of the Milky Way Galaxy is thought to be embedded in a much larger, roughly spherical halo of dark matter. The dark matter density drops off with distance from the galactic center. It is now believed that about 95% of the galaxy is composed of dark matter, a type of matter that does not seem to interact with the rest of the galaxy's matter and energy in any way except through gravity. The luminous matter makes up approximately solar masses. The dark matter halo is likely to include around to solar masses of dark matter. A 2014 Jeans analysis of stellar motions calculated the dark matter density (at the sun's distance from the galactic centre) = 0.0088 (+0.0024 −0.0018) solar masses/parsec^3.
See also
Press–Schechter formalism – A mathematical model used to predict the number of dark matter halos of a certain mass.
References
Further reading
External links
Rare Blob Unveiled: Evidence For Hydrogen Gas Falling Onto A Dark Matter Clump? European Southern Observatory (ScienceDaily) July 3, 2006
Dark Matter Search Experiment , PICASSO Experiment
Black Holes and Dark matter
Galaxies
Dark matter | Dark matter halo | Physics,Astronomy | 2,015 |
67,030,271 | https://en.wikipedia.org/wiki/Propionylation | Propionylation is a post-translational modification of proteins, in which a propionyl-group is added to a lysine amino acid of a protein. Propionylation participates in crucial biological processes, including metabolic processes and cellular stress response.
Lysine propionylation was first identified on histone proteins, and since has also been identified on other proteins. Histone propionylation is a mark of active chromatin. The substrate for protein propionylation is propionyl-CoA. Propionyl-CoA in the cell is metabolised by the enzyme propionyl-CoA carboxylase. Accumulation of propionyl-CoA leads to increased protein propionylation.
In patients with propionic acidemia, a rare autosomal recessive metabolic disorder, propionyl-CoA levels elevated and increased propionylation, which might contribute to the pathology in these patients.
References
Post-translational modification | Propionylation | Chemistry | 200 |
40,836,939 | https://en.wikipedia.org/wiki/Homocysteic%20acid | Homocysteic acid is the organosulfur compound with the formula . A white solid, it is sulfonic acid-containing non-proteinogenic amino acid. It is aanalog of glutamic acid and is a potent NMDA receptor agonist. It is related to homocysteine, a by-product of methionine metabolism.
Homocysteic acid is prepared by the oxidation of homocystine with aqueous bromine.
References
Alpha-Amino acids
Sulfonic acids
NMDA receptor agonists | Homocysteic acid | Chemistry | 115 |
26,024,577 | https://en.wikipedia.org/wiki/Microcosm%3A%20E.%20coli%20and%20the%20New%20Science%20of%20Life | Microcosm: E. coli and the New Science of Life is a 2008 book by science writer Carl Zimmer. The book presents an overview of genetics research and genetic engineering by telling the story about the Escherichia coli (E. coli) species of bacteria which is omnipresent in the mammalian gastrointestinal tract. The title Microcosm refers to the notion that insights derived from the study of a relatively simple, single-celled organism like E. coli play in describing the fundamental features of all terrestrial life, including humans.
Overview
Microcosm explores the history of E. colis role as a popular organism to study for researchers that has revealed how genes work and are regulated giving insight into evolution, behaviour and ecology. Beginning at its discovery in 1885 by pediatrician and microbiologist Theodor Escherich, through isolation of the strain K12 by Edward Tatum, and leading to the numerous Nobel prize winning research based on the K12 strain and its progeny, the book recounts the large number of scientific discoveries that have relied on this simple organism. The book continues on to reviews of modern and ongoing research leveraging E. coli including details about research exploring cellular nanomachines such as flagella and the composition and utility of microbial biofilms.
Evolution vs. intelligent design
The book makes the case that the flagellum and antibiotic resistance evolved and continue to evolve due to selection pressure. Zimmer devotes considerable attention to phenotypic plasticity and natural selection in E. coli genesis and notes that selection can be powered by humans individually (e.g., by antibiotic administration), collectively (e.g., by large-scale industrial food production), or inadvertently (e.g., by acting as host to a microbial pathogen). The book refutes the notion of intelligent design as the source of novel features of the organism, such as the flagellum that are capable of propelling E. coli, by exploring examples of more primitive, intermediate forms that, while useful, fall short of full utility of propulsion.
Though not a scientist himself, the acknowledgment section suggests that Zimmer’s theses have been vetted by multiple members of current E. coli researchers.
Publication Microcosm: E. coli and the New Science of Life''''' was first published by Pantheon Books on May 6, 2008, in hardcover format. A Reprint edition in softcover was subsequently published in by Vintage Books in 2009.
References
2008 non-fiction books
DNA replication
Popular science books | Microcosm: E. coli and the New Science of Life | Biology | 527 |
36,546,958 | https://en.wikipedia.org/wiki/Misicuni%20Dam | The Misicuni Multiplepurpose Project, better known as the Misicuni Dam, is a concrete-face rock-fill dam constructed on the Misicuni River about northwest of the city of Cochabamba, Bolivia. The dam will divert water from the Misicuni River to the Cochabamba Valley for several purposes to include providing water for irrigation and municipal water uses. In addition, the dam has an associated 120 MW hydroelectric power station, powered by 3 turbines 40 MW each. Construction on the dam began in June 2009 but was halted in November 2013 due to contract disputes. The company finished the construction and is started the operations in September 2017.
Characteristics and costs
The project has three components:
Phase I includes an already completed 20 km tunnel with the capacity to provide 2 cubic meters per second of drinking water and 1 cubic meter per second for irrigation to Cochabamba and the surrounding areas. Its cost was US$84 million.
Phase II includes a 120-meter-high concrete-face rock-fill dam with a 460-hectare reservoir with a storage capacity of 154 million cubic meters, as well as pipelines, pumping stations, a water treatment plant and an irrigation network to irrigate 4,000 hectares (under construction as of 2013). Its cost was also estimated at US$84 million,
Phase III includes a hydropower plant with an installed capacity of 120 MW at an estimated cost of US$200 million (under construction since April 2010). Water will be diverted from the reservoir through a long penstock to the plant.
The dam will be the highest and largest dam in Bolivia. Misicuni project director Ramiro Saniz said in 2009 that the water from the Misicuni river is not sufficient to fill the reservoir and that other sources are needed.
Background and construction progress
The public company in charge of developing the project is Proyecto Misicuni, an entity created by law in 1987. The contractor for the US$90 million dam component is the Consorcio Hidroelectrico Misicuni (CHM). The Misicuni consortium, led with 51 percent ownership by Grandi Lavori Fincosit S.p.A. of Italy, was the sole bidder for the project. Bidding was limited to Italian companies and CHM was the only company to submit a bid. The consortium also includes Bolivian, Colombian and Venezuelan firms.
The dam component was originally expected to be completed in 2014. However, in November 2013 the contract was canceled amid delays because CHM "failed to pay for pension funds, health insurances and other labour benefits and to contract key technical personnel."
Benefits
The tunnel provides 4.5-7.5 million cubic meters of water per year to Cochabamba since 2005, depending on whether the flow of the river is low or high and supplying about 10 percent of the city's drinking water. Once the dam will be completed, the amount of drinking water available will increase tenfold to 63 million cubic meters per year.
Environmental and social impact
1365 people live in the reservoir area that will be flooded and will be relocated. The Tunari National Park will also be affected.
Financing
The dam is partially financed by the Italian government through a 25 million Euro loan and the Development Bank of Latin America and the Caribbean (CAF). Total funding from Italy for Phased II and III is USD 93 million. Bolivia will have to pay back the loan over in 20 years with a 0.10% interest rate.
The construction of the penstock, hydropower plant and power transmission line is funded by a US$101 million loan from the Inter-American Development Bank approved in 2009. These works were expected to be completed by 2015, but were only 30 percent completed as of April 2013.
Climate
References
Dams in Bolivia
Buildings and structures in Cochabamba Department
Concrete-face rock-fill dams
Hydroelectric power stations in Bolivia
Interbasin transfer | Misicuni Dam | Environmental_science | 794 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.