source stringlengths 31 227 | text stringlengths 9 2k |
|---|---|
https://en.wikipedia.org/wiki/Dyadics | In mathematics, specifically multilinear algebra, a dyadic or dyadic tensor is a second order tensor, written in a notation that fits in with vector algebra.
There are numerous ways to multiply two Euclidean vectors. The dot product takes in two vectors and returns a scalar, while the cross product returns a pseudovector. Both of these have various significant geometric interpretations and are widely used in mathematics, physics, and engineering. The dyadic product takes in two vectors and returns a second order tensor called a dyadic in this context. A dyadic can be used to contain physical or geometric information, although in general there is no direct way of geometrically interpreting it.
The dyadic product is distributive over vector addition, and associative with scalar multiplication. Therefore, the dyadic product is linear in both of its operands. In general, two dyadics can be added to get another dyadic, and multiplied by numbers to scale the dyadic. However, the product is not commutative; changing the order of the vectors results in a different dyadic.
The formalism of dyadic algebra is an extension of vector algebra to include the dyadic product of vectors. The dyadic product is also associative with the dot and cross products with other vectors, which allows the dot, cross, and dyadic products to be combined to obtain other scalars, vectors, or dyadics.
It also has some aspects of matrix algebra, as the numerical components of vectors can be arranged into row and column vectors, and those of second order tensors in square matrices. Also, the dot, cross, and dyadic products can all be expressed in matrix form. Dyadic expressions may closely resemble the matrix equivalents.
The dot product of a dyadic with a vector gives another vector, and taking the dot product of this result gives a scalar derived from the dyadic. The effect that a given dyadic has on other vectors can provide indirect physical or geometric interpretations.
Dyadic notation was f |
https://en.wikipedia.org/wiki/Coccyx | The coccyx (: coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horses. In tailless primates (e.g. humans and other great apes) since Nacholapithecus (a Miocene hominoid), the coccyx is the remnant of a vestigial tail. In animals with bony tails, it is known as tailhead or dock, in bird anatomy as tailfan. It comprises three to five separate or fused coccygeal vertebrae below the sacrum, attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the coccyx.
Structure
The coccyx is formed of three, four or five rudimentary vertebrae. It articulates superiorly with the sacrum. In each of the first three segments may be traced a rudimentary body and articular and transverse processes; the last piece (sometimes the third) is a mere nodule of bone. The transverse processes are most prominent and noticeable on the first coccygeal segment. All the segments lack pedicles, laminae and spinous processes. The first segment is the largest; it resembles the lowest sacral vertebra, and often exists as a separate piece; the remaining ones diminish in size rostrally.
Most anatomy books incorrectly state that the coccyx is normally fused in adults. It has been shown that the coccyx may, in some people, consist of up to five separate bony segments, the most common configuration being two or three segments.
Surfaces
The anterior surface is slightly concave and marked with three transverse grooves which indicate the junctions of the different segments. It gives attachment to the anterior sacrococcygeal ligament and the levatores ani and supports part of the rectum. The posterior surface is convex, marked by transverse grooves similar to those on the anterior surface, and presents on either side a linear row of tubercles – the undeveloped articular processes of the coccygeal ve |
https://en.wikipedia.org/wiki/Urbilaterian | The urbilaterian (from German ur- 'original') is the hypothetical last common ancestor of the bilaterian clade, i.e., all animals having a bilateral symmetry.
Appearance
Its appearance is a matter of debate, for no representative has been (or may or may not ever be) identified in the fossil record. Two reconstructed urbilaterian morphologies can be considered: first, the less complex ancestral form forming the common ancestor to Xenacoelomorpha and Nephrozoa; and second, the more complex (coelomate) urbilaterian ancestral to both protostomes and deuterostomes, sometimes referred to as the "urnephrozoan". Since most protostomes and deuterostomes share features — e.g. nephridia (and the derived kidneys), through guts, blood vessels and nerve ganglia— that are useful only in relatively large (macroscopic) organisms, their common ancestor ought also to have been macroscopic. However, such large animals should have left traces in the sediment in which they moved, and evidence of such traces first appear relatively late in the fossil record — long after the urbilaterian would have lived. This leads to suggestions of a small urbilaterian (around 1 mm) which is the supposed state of the ancestor of protostomes, deuterostomes and acoelomorphs.
Dating the urbilaterian
The first evidence of bilateria in the fossil record comes from trace fossils in sediments towards the end of the Ediacaran period (about ), and the first fully accepted fossil of a bilaterian organism is Kimberella, dating to . There are earlier, controversial fossils: Vernanimalcula has been interpreted as a bilaterian, but may simply represent a fortuitously infilled bubble. Fossil embryos are known from around the time of Vernanimalcula (), but none of these have bilaterian affinities. This may reflect a genuine absence of bilateria, however it is likely this is the case as bilateria may not have laid their eggs in sediment, where they would be likely to fossilise.
Molecular techniques can generate e |
https://en.wikipedia.org/wiki/Scalable%20Cluster%20Environment | OpenSCE (Open Scalable Cluster Environment) is an Open-source beowulf-clustering software suite led by Kasetsart University, Thailand. It started from a small system monitoring for cluster, called SCMS (Scalable Cluster Monitoring System) and extend from its base to many sub-project. Currently OpenSCE has the following components
Components
SCEBase - Core system library and command line
SCMS (Scalable Cluster Monitoring System) - Cluster monitoring. Including some command line tools for cluster management
SCMSWeb - Grid & Cluster web-base monitoring system
MPITH - A thin layer of MPI that focus on light & robust implementation
MPView - A visual profiling and debugger for parallel program
OpenSCE Roll - A bundled of components to install in a NPACI Rocks cluster distribution.
Currently, OpenSCE project has been moved into umbrella of Thai National Grid Project, led by Thai National Grid Center.
Some components of OpenSCE, especially SCMSWeb, has been used to monitor many Grid computing researches. Such as PRAGMA, APGrid, and also Thai National Grid.
External links
OpenSCE Project
Thai National Grid Project
Internet Protocol based network software
Parallel computing
Grid computing |
https://en.wikipedia.org/wiki/Spiral%20hashing | Spiral hashing, also known as Spiral Storage is an extensible
hashing algorithm. As in all hashing schemes, spiral hashing stores records in a varying number of buckets, using a record key for addressing. In an expanding Linear hashing file, buckets are split in a predefined order. This results in adding a new bucket at the end of the file. While this allows gradual reorganization of the file, the expected number of records in the newly created bucket and the bucket from what it splits falls to half the previous number. Several attempts were made to alleviate this sudden drop in space utilization. Martin's spiral storage uses a different approach. The file consists of a number of continuously numbered buckets. The lower-numbered (left) buckets have a higher expected number of records. When the file expands, the left-most bucket is replaced by two buckets on the right. Some variants of this idea exist.
Spiral hashing requires a uniform hash function of the keys of the records into the unit interval . If the hash file starts at bucket , the key is mapped into a real number . The final address is then computed as where is the "extension factor". When is incremented, approximately new buckets are created on the right. Larson conducted experiments that showed that Linear hashing still had superior performance over Spiral Hashing.
See also
Extendible hashing
Linear hashing |
https://en.wikipedia.org/wiki/Green%20Fire%20%28novel%29 | Green Fire is a science fiction novel by American writer John Taine (pseudonym of Eric Temple Bell). It was first published in 1928 by E. P. Dutton. The novel was adapted and produced as a play.
Plot introduction
The novel concerns two corporations competing to develop the power of atomic energy. Independent Laboratories is working for the advancement of mankind, and Consolidated Power is working for personal gain. Nature goes berserk, and James Ferguson, the leader of Independent, discovers that Jevic, the Director of Consolidated, has achieved his goal. Nebulae in space are marked with a greenish glow and then are obliterated. MacRobert, who has previously refused offers from either corporation, is placed in charge of Independent. He disposes of Jevic in time to end the destruction.
Reception
Basil Davenport, reviewing the novel for The New York Times, faulted the story's "psychological crudities," but noted that Green Fire was also marked by "some striking concepts, and a duel of powers with real suspense."
Everett F. Bleiler faulted the novel for defects including "poor exposition," noted that Jevic was modeled on Nikola Tesla, and found the fictionalized account of his early life "fascinating." |
https://en.wikipedia.org/wiki/Mathematical%20Olympiad%20Program | The Mathematical Olympiad Program (abbreviated MOP; formerly called the Mathematical Olympiad Summer Program, abbreviated MOSP) is an intensive summer program held at Carnegie Mellon University. The main purpose of MOP, held since 1974, is to select and train the six members of the U.S. team for the International Mathematical Olympiad (IMO).
Selection Process
Students qualify for the program by taking the United States of America Mathematical Olympiad (USAMO). The top twelve American scorers from all grades form the "black" group. The approximately eighteen next highest American scorers among students from 11th grade and under form the "blue" group.
In 2004, the program was expanded to include approximately thirty of the highest-scoring American freshmen and sophomores each year, the "red" group; this was later split into two, forming the "green" group, which consists of approximately fifteen of the highest-scoring freshmen and sophomores who have qualified through the USAMO, and the "red" group, which consists of those who have qualified through the USAJMO. The colorful designations of these groups were adapted from Karate. Also, with the new system the black group includes more or less only the IMO team, which is not necessarily all USAMO winners.
Until 2011, only black group MOPpers were eligible for the selection to the USA IMO team, determined by combining USAMO results with results of a similar competition called the Team Selection Test (TST). From 2011, a new competition called the Team Selection Test Selection Test (TSTST) was established; this competition is open for any of the participants of MOP, and along with results from the USAMO, determines the students who take the TSTs. This ultimately, along with the USAMO and MOP competitions, determines the IMO team.
Canadians are allowed to take the USAMO, but are not allowed to participate in MOP unless they are U.S. residents. Occasionally, when Canadians are amongst the USAMO winners, top scoring honora |
https://en.wikipedia.org/wiki/375-line%20television%20system | 375-line corresponds to two different electronic television systems, both using 375 scan lines. One system (monochrome, 50 fields per second, interlaced) was used in Germany after 1936 along with the 180-line system, being replaced in a few years by the superior 441-line system. It was also tested in Italy around the same time.
In the United States a completely different system (field sequential color, 120 fields per second, interlaced) was used for early color television broadcasts
Germany
375-line (50 fps, interlaced) television was demonstrated in 1936 on the Berlin Funkausstellung. The system used electronic cameras for live exterior broadcasts.
The system was also used on experimental transmissions of the 1936 Summer Olympics (along with the 180-line system), using the Telefunken Iconoscope camera. A transmitter was setup in Berlin-Witzleben, broadcasting at 42.9 MHz. The Reichspost distributed the signal to major cities across Germany using cables.
After the Games transmissions continued to viewing rooms installed on post offices. Philips presented a radio/TV combo receiver for the system at the 1937 Berlin Funkausstellung, and Loewe also had a receiver available.
In the same year Telefunken demonstrated the 375-line system at the Paris Exposition Internationale des Arts et Techniques dans la Vie Moderne, displaying images taken from the exhibition's pavilion terrace.
Italy
In Italy 375-line television transmissions were undertaken by Arturo Castellani in 1937, with daily broadcasts from Rome, between 6pm and 9:30pm on 6.9 meters (43.45 MHz) with a power of 2 kW.
United States
In the spring of 1940, CBS staff engineer Peter Goldmark devised a system for color television, hoping to gain advantage regarding NBC and its black-and-white RCA system. The new system proposed by CBS was based on field sequential color and incompatible with existing sets but "gave brilliant and stable colors", while NBC developed a black and white compatible color TV system |
https://en.wikipedia.org/wiki/Caribbean%20Knowledge%20and%20Learning%20Network | The Caribbean Knowledge and Learning Network (CKLN) is an inter-governmental agency of the Caribbean Community, CARICOM, responsible for developing and managing a high capacity, broadband fiber optic network called C@ribNET, connecting all CARICOM member states.
The Caribbean Knowledge Learning Network Agency was first proposed in 2002 at a meeting where the 7 Prime Ministers of Eastern Caribbean States and Barbados met with the president of the World Bank. It was established in 2004 as an institution of the CARICOM, under the authority of Article 21 of the Revised Treaty of Chaguaramas.
Academic computer network organizations |
https://en.wikipedia.org/wiki/Stem%20Cell%20Therapeutic%20and%20Research%20Act%20of%202005 | The Stem Cell Therapeutic and Research Act of 2005 () is a United States federal law that assigns the United States Secretary of Health and Human Services to create a national stockpile of cord blood stem cells, and rewrites provisions within the Public Health Service Act to account for cord blood and bone marrow donors.
Legislative history
The House bill (HR-2520) was introduced on May 23, 2005, by Rep. Chris Smith of New Jersey. On December 20, 2005, the bill was signed by the President after passing through both chambers with unanimous consent. |
https://en.wikipedia.org/wiki/IEEE%20Transactions%20on%20Magnetics | IEEE Transactions on Magnetics is a monthly peer-reviewed scientific journal that covers the basic physics of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage. The editor-in-chief is Amr Adly (Cairo University, Egypt).
Abstracting and indexing
The journal is abstracted and indexed in the Science Citation Index, Current Contents/Physical, Chemical & Earth Sciences, Scopus, CSA databases, and EBSCOhost. According to the Journal Citation Reports, the journal has a recent impact factor of 2.1. |
https://en.wikipedia.org/wiki/LumenVox | LumenVox is a privately held speech recognition software company based in San Diego, California. LumenVox has been described as one of the market leaders in the speech recognition software industry.
History
LumenVox was founded in 2001 as subsidiary of Progressive Computing. According to LumenVox CEO Edward Miller, when Progressive had initially looked to add speech recognition to its own phone system, it found the existing offerings too expensive and recognized a niche in the market for a more affordable speech recognition product. This led to the development of LumenVox with an aim to bring speech recognition to small-to-midsized businesses.
LumenVox is one of the major providers of automatic speech recognition for telephone systems, and as of 2006, became the second largest provider of speech recognition software.
Products
The primary LumenVox product is the LumenVox Speech Engine. It is a speaker-independent automatic speech recognizer that uses the Speech Recognition Grammar Specification for building and defining grammars. It has been integrated with several of the major voice platforms, including Avaya Voice Portal/Interactive Response, Aculab, and BroadSoft's BroadWorks. The Speech Engine was originally derived from CMU Sphinx, but LumenVox has added considerable development effort to make it a commercial-ready product.
LumenVox also offers a product called the Speech Tuner, which provides a graphical means of testing and troubleshooting speech recognition applications.
Open source support
LumenVox was recognized as one of the top VoIP companies in 2008 for its work in providing its offerings to the open source community, an effort by the company that began in 2006 when it partnered with Digium. At that time, Digium, maintainer of the open source Asterisk PBX, integrated the LumenVox Speech Engine into Asterisk. This made LumenVox the first commercially available speech recognition engine for Asterisk.
As one of the earlier commercial software integ |
https://en.wikipedia.org/wiki/Primary%20bone | Primary bone is the first bone tissue that appears in embryonic development and in fracture repair. It is characterized by its random position of collagen fibers. In most places in adults this tissue is replaced by secondary bone tissue except, for example, near the sutures of calvara or tooth sockets. The secondary bones have lower amounts of osteocytes so primary bone is much more easily penetrated by x-ray.
Clinical significance
Primary bone or the primary ossification center is the beginning of the bone building process during the first trimester. Calcificed cartilage is basophilic and new bone being made is more acidophilic.
The primary ossification occurs in the diaphysis. In contrast, secondary ossification centers appear later at the epiphyses of the cartilage and develop similarly to the diaphysis.
Cancer
Primary bone cancer is a type of sarcoma, a cancer that originates in bone, muscle, fibrous tissue, blood vessels, fat tissue, as well as some other tissues. Primary bone cancer can arise in any of the 206 bones in the body but is mostly seen to originate the arms and the legs. The most common cases are observed in children and young adults. The following list includes types of primary bone cancer:
Osteosarcoma
Chondrosarcoma
Ewing's Sarcoma
Adamantinomas
Chordomas
See also
Somite
Somitogenesis |
https://en.wikipedia.org/wiki/Superior%20parietal%20lobule | The superior parietal lobule is bounded in front by the upper part of the postcentral sulcus, but is usually connected with the postcentral gyrus above the end of the sulcus. The superior parietal lobule contains Brodmann's areas 5 and 7.
Behind it is the lateral part of the parietooccipital fissure, around the end of which it is joined to the occipital lobe by a curved gyrus, the arcus parietooccipitalis. Below, it is separated from the inferior parietal lobule by the horizontal portion of the intraparietal sulcus.
The superior parietal lobule is involved with spatial orientation, and receives a great deal of visual input as well as sensory input from one's hand. In addition to spatial cognition and visual perception, it has also been associated with reasoning, working memory, and attention.
It is also involved with other functions of the parietal lobe in general.
There are major white matter pathway connections with the superior parietal lobule such as the Cingulum, SLF I, superior parietal lobule connections of the Medial longitudinal fasciculus and other newly described superior parietal white matter connections.
Damage to the superior parietal lobule can cause contralateral astereognosis and hemispatial neglect. It is also associated with deficits on tests involving the manipulation and rearrangement of information in working memory, but not on working memory tests requiring only rehearsal and retrieval processes.
Additional images |
https://en.wikipedia.org/wiki/Storm%20spotting | Storm spotting is a form of weather spotting in which observers watch for the approach of severe weather, monitor its development and progression, and actively relay their findings to local authorities.
History
Storm spotting developed in the United States during the early 1940s. A joint project between the military and the weather bureau saw the deployment of trained military and aviation lightning spotters in areas where ammunitions for the war were manufactured. During 1942, a serious tornado struck a key operations center in Oklahoma and another tornado on May 15, 1943 destroyed parts of the Fort Riley military base located in Kansas. After these two events and a string of other tornado outbreaks, spotter networks became commonplace, and it is estimated that there were over 200 networks by 1945. Their mandate had also changed to include reporting all types of active or severe weather; this included giving snow depth and other reports during the winter as well as fire reports in the summer, along with the more typical severe weather reports associated with thunderstorms. However, spotting was still mainly carried out by trained individuals in either the military, aviation, or law enforcement fields of service. It was not until 1947 that volunteer spotting, as it exists today, was born.
After a series of vicious tornado outbreaks hit the state of Texas in 1947, the state placed special emphasis on volunteer spotting, and the local weather offices began to offer basic training classes to the general public. Spotting required the delivery of timely information so that warnings could be issued as quickly as possible, thus civilian landline phone calls and amateur radio operators provided the most efficient and fastest means of communication. While phone lines were reliable to a degree, a common problem was the loss of service when an approaching storm damaged phone lines in its path. This eventually led to amateur radio becoming the predominant means of communicat |
https://en.wikipedia.org/wiki/IEEE%20802.19 | IEEE 802.19 is the Wireless Coexistence Working Group (WG) within the IEEE 802 LAN/MAN Standards Committee. The WG deals with coexistence between unlicensed wireless networks. Many of the IEEE 802 wireless standards use unlicensed spectrum and hence need to address the issue of coexistence. These unlicensed wireless devices may operate in the same unlicensed frequency band in the same location. This can lead to interference between these two wireless networks.
Background
Multiple unlicensed wireless networks are said to coexist if they can operate in the same location. Positive coexistence occurs when multiple wireless networks coexist without causing significant performance degradation to one another. One of the first examples of wireless coexistence addressed within the IEEE 802 LAN/MAN Standards Committee was between IEEE 802.11 and Bluetooth, both operating in the 2.4 GHz ISM frequency band. Achieving positive coexistence between these two wireless networks was addressed by the IEEE 802.15 Task Group 2, which produced a Recommended Practice on Coexistence of IEEE 802.11 and Bluetooth.
Overview
Currently the 802.19 WG addresses coexistence between wireless standards under development within IEEE 802. There are a number of IEEE 802 wireless standards which may use unlicensed spectrum and for which coexistence must be considered by the Working Groups developing standards. These include
IEEE 802.11 Wireless Local Area Networks (WLAN)
IEEE 802.15 Wireless Personal Area Networks (WPAN)
IEEE 802.16 Wireless Metropolitan Area Networks (WMAN)
IEEE 802.22 Wireless Regional Area Networks (WRAN)
Not that the IEEE 802.16 and IEEE 802.22 Working Groups have been merged into the IEEE 802.15 Working Group.
When a new standard (or amendment to a standard) for an unlicensed wireless network is being developed the working group may develop a Coexistence Assessment (CA) document that is reviewed the IEEE 802.19 WG. In addition to evaluating CA documents, The IEEE 802 |
https://en.wikipedia.org/wiki/Disintegrin | Disintegrins are a family of small proteins (45–84 amino acids in length) from viper venoms that function as potent inhibitors of both platelet aggregation and integrin-dependent cell adhesion.
Operation
Disintegrins work by countering the blood clotting steps, inhibiting the clumping of platelets. They interact with the beta-1 and -3 families of integrins receptors. Integrins are cell receptors involved in cell–cell and cell–extracellular matrix interactions, serving as the final common pathway leading to aggregation via formation of platelet–platelet bridges, which are essential in thrombosis and haemostasis. Disintegrins contain an RGD (Arg-Gly-Asp) or KGD (Lys-Gly-Asp) sequence motif that binds specifically to integrin IIb-IIIa receptors on the platelet surface, thereby blocking the binding of fibrinogen to the receptor–glycoprotein complex of activated platelets. Disintegrins act as receptor antagonists, inhibiting aggregation induced by ADP, thrombin, platelet-activating factor and collagen. The role of disintegrin in preventing blood coagulation renders it of medical interest, particularly with regard to its use as an anti-coagulant.
Types of disintegrin
Disintegrins from different snake species have been characterised: albolabrin, applagin, barbourin, batroxostatin, bitistatin, obtustatin, schistatin, echistatin, elegantin, eristicophin, flavoridin, halysin, kistrin, mojastin (Crotalus scutulatus), rubistatin (Crotalus ruber), tergeminin, salmosin, tzabcanin (Crotalus simus tzabcan) and triflavin.
Disintegrins are split into 5 classes: small, medium, large, dimeric, and snake venom metalloproteinases.
Small Disintegrins: 49-51 amino acids, 4 disulfide bonds
Medium Disintegrins: 70 amino acids, 6 disulfide bonds
Large Disintegrins: 84 amino acids, 7 disulfide bonds
Dimeric Disintegrins: 67 amino acids, 4 intra-chain disulfide bonds
Snake Venom Metalloproteinases: 100 amino acids, 8 disulfide bond
Evolution of disintegrin family
Disintegrins evolved via g |
https://en.wikipedia.org/wiki/Magnetic%20circular%20dichroism | Magnetic circular dichroism (MCD) is the differential absorption of left and right circularly polarized (LCP and RCP) light, induced in a sample by a strong magnetic field oriented parallel to the direction of light propagation. MCD measurements can detect transitions which are too weak to be seen in conventional optical absorption spectra, and it can be used to distinguish between overlapping transitions. Paramagnetic systems are common analytes, as their near-degenerate magnetic sublevels provide strong MCD intensity that varies with both field strength and sample temperature. The MCD signal also provides insight into the symmetry of the electronic levels of the studied systems, such as metal ion sites.
History
It was first shown by Faraday that optical activity (the Faraday effect) could be induced in matter by a longitudinal magnetic field (a field in the direction of light propagation). The development of MCD really began in the 1930s when a quantum mechanical theory of MOR (magnetic optical rotatory dispersion) in regions outside absorption bands was formulated. The expansion of the theory to include MCD and MOR effects in the region of absorptions, which were referred to as “anomalous dispersions” was developed soon thereafter. There was, however, little effort made to refine MCD as a modern spectroscopic technique until the early 1960s. Since that time there have been numerous studies of MCD spectra for a very large variety of samples, including stable molecules in solutions, in isotropic solids, and in the gas phase, as well as unstable molecules entrapped in noble gas matrices. More recently, MCD has found useful application in the study of biologically important systems including metalloenzymes and proteins containing metal centers.
Differences between CD and MCD
In natural optical activity, the difference between the LCP light and the RCP light is caused by the asymmetry of the molecules (i.e. chiral molecules). Because of the handedness of the molecu |
https://en.wikipedia.org/wiki/RAF%20Ash | Royal Air Force Ash or more simply RAF Ash (formerly RAF Sandwich) was a Royal Air Force underground control centre and radar station situated near the village of Woodnesborough, Kent, England.
History
RAF Sandwich
RAF Sandwich was originally a Ground Controlled Interception (GCI) site situated in Ash Road, Sandwich. However, after the Second World War the area was chosen for one of a chain of ROTOR air defence radar stations and the site was relocated to an underground bunker 1.5 miles to the southwest in Marshborough Road, Ash. The site later closed on 1 October 1958 and was sold on 22 March 1965.
RAF Ash
In 1980 the site was re-acquired by the RAF for the development of Improved UK Air Defence Ground Environment (IUKADGE) and became operational as RAF Ash on 6 January 1986. It closed as an RAF station in 1995. The Ministry of Defence sold the site on 24 July 1998.
Post-closure
The site is now used as a secure data centre by The Bunker, an Internet hosting company. |
https://en.wikipedia.org/wiki/International%20Clinical%20Research%20Center | International Clinical Research Center Brno (ICRC) is a conceptually novel project in biomedical research and clinical patient care which is being developed by the Czech Republic and the Mayo Clinic in Rochester, Minnesota. The goal of ICRC consists of creating a research platform to allow cutting edge clinical research being conducted in the central Europe, particularly in Brno, Czech Republic.
Origins of the ICRC Project
At the beginning of the ICRC concept was a close and fruitful collaboration between physicians and researchers in the Cardiology Department of St. Anne’s Hospital in Brno, Czech Republic, and their counterparts at the Division of Cardiovascular Diseases at the Mayo Clinic, Rochester, Minnesota. Particularly the stay of MUDr. Tomas Kara, Ph.D. in the laboratory of Dr. Virend Somers at the Mayo clinic in early 2000 established the high yield of such cooperation, and led to the origins of the idea that a new and globally competitive scientific facility would be needed in Brno, Czech Republic, to support the increasing depth and complexity of research projects being conducted by Mayo and St. Anne’s Hospital. The team led by Dr. Kara ultimately recommended building of a new facility (ICRC) in St. Anne’s Hospital in Brno, Czech Republic which would be sufficiently equipped to support an ongoing global cooperation with the world-wide leader in translational biomedical research, the Mayo Clinic.
Building of ICRC Brno
The ICRC project was supported by both the Mayo Clinic, and by the government of the Czech Republic in a Memorandum of Understanding, and this ultimately led to the beginning of construction of the ICRC scientific facility. The foundation stone was laid on October 7, 2008 in Brno, Czech Republic with the presence of the Prime Minister of the Czech Republic, the Ambassador of the United States to the Czech Republic, the leadership of the ICRC project, and the local government and community leaders from the South Moravia region.
Results |
https://en.wikipedia.org/wiki/Huntingdon%20Life%20Sciences | Huntingdon Life Sciences (HLS) was a contract research organisation (CRO) founded in 1951 in Cambridgeshire, England. It had two laboratories in the United Kingdom and one in the United States. With over 1,600 staff, it was until 2015 the largest non-clinical CRO in Europe. In September 2015, Huntingdon Life Sciences, Harlan Laboratories, GFA, NDA Analytics and LSR associates merged into Envigo, which later sold off the CRO part.
In 2009, HLS was bought outright and is now in private ownership. Prior to this, the latest annual report (2008) showed that the company had revenues of $US242.4m and an operating profit of 14.8%.
HLS is the third-largest non-clinical CRO in the world, and gained substantial attention for a high-profile animal rights campaign organized in response to its operations.
Locations
HLS has two facilities in the UK (Huntingdon, Cambridgeshire and Eye, Suffolk), one in the USA (East Millstone, New Jersey) and an office in Japan (Tokyo).
History
Huntingdon Life Sciences was founded in the UK in 1951 as Nutrition Research Co. Ltd., a commercial organisation that initially focused on nutrition, veterinary, and biochemical research. The original facilities were split over two locations; the main offices were within Cromwell House in the town of Huntingdon, Cambs, UK; and the main laboratories were at the Hartford Field Station (just over a mile away). It then became involved with pharmaceuticals, food additives, and industrial and consumer chemicals. In 1959 it changed its name to Nutritional Research Unit Ltd. The company benefited in the early 1960s from increased government regulatory testing requirements, especially in the pharmaceutical industry. In 1964 it was acquired by the U.S. medical supply firm of Becton Dickinson.
In April 1983, Becton Dickinson created Huntingdon Research Centre PLC. It then offered four million American depositary receipts (ADRs) for sale at $15 each, representing the company's entire interest in Huntingdon. In 1985 |
https://en.wikipedia.org/wiki/University%20Marine%20Biological%20Station%20Millport | The University Marine Biological Station Millport (UMBSM) was a higher education institution located on the island of Great Cumbrae in the Firth of Clyde, Scotland, and run by the university of London (of which it was a central academic body). It closed in 2013 and is now Millport Field Centre, run by the Field Studies Council.
Located just outside the town, it had an extensive curriculum and research programme, with an influx of students throughout the academic year. A Museum and Aquarium (named after the founder, David Robertson) were open to visitors. In May 2003, the station took delivery of the Macduff-built, 22-metre marine research vessel RV Aora. The station also functioned as a Meteorological Office Weather Station and Admiralty Tide Monitor.
History
The Ark, an lighter, was fitted out as a floating laboratory by the father of modern oceanography, Sir John Murray. She formed the Scottish Marine Station for 12 years from 1884. In 1885 she was moved from Granton and drawn up on the shore at Port Loy, Cumbrae. She attracted a stream of distinguished scientists, drawn by the richness of the fauna and flora of the Firth of Clyde, but closed in 1903.
In Millport, an amateur naturalist, David Robertson, was encouraged by meeting Anton Dohrn and by the wealth of findings from the Challenger expedition. In 1894 he formed a committee to build a marine station in Millport and took over The Ark. Millport Marine Biological Station was opened in 1897 by Sir John Murray. The Ark was totally destroyed by a great storm on the night of 20 January 1900.
On 21 July 1904 Scotia, the ship of Dr William Speirs Bruce's Scottish National Antarctic Expedition, returned to her first Scottish landing site, on the Isle of Cumbrae.
From this beginning the station was gradually built up to its present size. The original building proved too small for the purpose and an architectural copy was built alongside. From 1966 to 1987 the station ran under the Directorship of Ronald Ian Cur |
https://en.wikipedia.org/wiki/Mating%20bridge | A mating bridge, also known as a conjugation or population bridge, is a connection between two bacterial cells that provides a passageway for DNA in bacterial conjugation.
A mating bridge is different from a sex pilus, which is a structure made by an F+ strain bacterium in bacterial conjugation. The pili (plural) act as attachment sites that promote the binding of bacteria to each other. In this way, an F+ strain makes physical contact with an F− strain. Once contact is made, the pili shorten and thereby draw the donor and recipient cells closer together. A conjugation bridge is then formed between the two cells, which provides a passageway for DNA transfer. |
https://en.wikipedia.org/wiki/Gideon%20Schechtman | Gideon Schechtman (; born 14 February 1947) is an Israeli mathematician and professor of mathematics at the Weizmann Institute of Science.
Academic career
Schechtman received his Ph.D. in mathematics from the Hebrew University of Jerusalem in 1976 and was a postdoctoral fellow at Ohio State University.
Since 1980 he has been affiliated with the Weizmann Institute, where he became emeritus professor in 2017. His research focuses predominantly on functional analysis and the geometry of Banach spaces. Schechtman is an editor of the Israel Journal of Mathematics. |
https://en.wikipedia.org/wiki/DTE%20%28direct%20to%20edit%29 | DTE (direct to edit) is a digital video direct-to-disk recording method (and also refers to the associated equipment) used to streamline the post-production video editing workflow of raw video files into a non-linear editing system (NLE). Recent developments have added solid-state memory recording units with removable modules or flash-cards, to avoid potential hard-drive problems.
See also
Computer file
Data storage device
Digital video recorder (DVR)
Flash memory
Hard disk drive (HDD)
Non-linear editing system (NLE)
Professional video camera
Tapeless camcorder
Video editing software
Video server |
https://en.wikipedia.org/wiki/Lipoexpediency | Lipoexpediency refers to the beneficial effects of lipids in a cell or a tissue, primarily lipid-mediated signal transmission events, that may occur even in the setting of excess fatty acids. The term was coined as an antonym to lipotoxicity.
See also
Lipotoxicity |
https://en.wikipedia.org/wiki/Forbidden%20graph%20characterization | In graph theory, a branch of mathematics, many important families of graphs can be described by a finite set of individual graphs that do not belong to the family and further exclude all graphs from the family which contain any of these forbidden graphs as (induced) subgraph or minor.
A prototypical example of this phenomenon is Kuratowski's theorem, which states that a graph is planar (can be drawn without crossings in the plane) if and only if it does not contain either of two forbidden graphs, the complete graph and the complete bipartite graph . For Kuratowski's theorem, the notion of containment is that of graph homeomorphism, in which a subdivision of one graph appears as a subgraph of the other. Thus, every graph either has a planar drawing (in which case it belongs to the family of planar graphs) or it has a subdivision of at least one of these two graphs as a subgraph (in which case it does not belong to the planar graphs).
Definition
More generally, a forbidden graph characterization is a method of specifying a family of graph, or hypergraph, structures, by specifying substructures that are forbidden to exist within any graph in the family. Different families vary in the nature of what is forbidden. In general, a structure G is a member of a family if and only if a forbidden substructure is not contained in G. The forbidden substructure might be one of:
subgraphs, smaller graphs obtained from subsets of the vertices and edges of a larger graph,
induced subgraphs, smaller graphs obtained by selecting a subset of the vertices and using all edges with both endpoints in that subset,
homeomorphic subgraphs (also called topological minors), smaller graphs obtained from subgraphs by collapsing paths of degree-two vertices to single edges, or
graph minors, smaller graphs obtained from subgraphs by arbitrary edge contractions.
The set of structures that are forbidden from belonging to a given graph family can also be called an obstruction set for that fa |
https://en.wikipedia.org/wiki/Oscar%20Hertwig | Oscar Hertwig (21 April 1849 in Friedberg – 25 October 1922 in Berlin) was a German embryologist and zoologist known for his research in developmental biology and evolution. Hertwig is credited as the first man to observe sexual reproduction by looking at the cells of sea urchins under the microscope.
Biography
Hertwig was the elder brother of zoologist-professor Richard Hertwig (1850–1937). The Hertwig brothers were the most eminent scholars of Ernst Haeckel (and Carl Gegenbaur) from the University of Jena. They were independent of Haeckel's philosophical speculations but took his ideas in a positive way to widen their concepts in zoology. Initially, between 1879 and 1883, they performed embryological studies, especially on the theory of the coelom (1881), the fluid-filled body cavity. These problems were based on the phylogenetic theorems of Haeckel, i.e. the biogenic theory (German = biogenetisches Grundgesetz), and the "gastraea theory".
Within 10 years, the two brothers moved apart to the north and south of Germany.
Oscar Hertwig later became a professor of anatomy in 1888 in Berlin; however, Richard Hertwig had moved 3 years prior, becoming a professor of zoology in Munich from 1885 to 1925, at Ludwig Maximilian University, where he served the last 40 years of his 50-year career as a professor at 4 universities.
Hertwig was a leader in the field of comparative and causal animal-developmental history. He also wrote a leading textbook. By studying sea urchins he proved that fertilization occurs due to the fusion of a sperm and egg cell. He recognized the role of the cell nucleus during inheritance and chromosome reduction during meiosis: in 1876, he published his findings that fertilization includes the penetration of a spermatozoon into an egg cell. Hermann Fol also observed this in the same year.
Hertwig's experiments with frog eggs revealed the 'long axis rule', or Hertwig rule. According to this rule, cell divides along its long axis.
In 1885 Hertwig w |
https://en.wikipedia.org/wiki/Mahler%20polynomial | In mathematics, the Mahler polynomials gn(x) are polynomials introduced by in his work on the zeros of the incomplete gamma function.
Mahler polynomials are given by the generating function
Which is close to the generating function of the Touchard polynomials.
The first few examples are |
https://en.wikipedia.org/wiki/Geometry%20of%20binary%20search%20trees | In computer science, one approach to the dynamic optimality problem on online algorithms for binary search trees involves reformulating the problem geometrically, in terms of augmenting a set of points in the plane with as few additional points as possible in order to avoid rectangles with only two points on their boundary.
Access sequences and competitive ratio
As typically formulated, the online binary search tree problem involves search trees defined over a fixed key set . An access sequence is a sequence ... where each access belongs to the key set.
Any particular algorithm for maintaining binary search trees (such as the splay tree algorithm or Iacono's working set structure) has a cost for each access sequence that models the amount of time it would take to use the structure to search for each of the keys in the access sequence in turn. The cost of a search is modeled by assuming that the search tree algorithm has a single pointer into a binary search tree, which at the start of each search points to the root of the tree. The algorithm may then perform any sequence of the following operations:
Move the pointer to its left child.
Move the pointer to its right child.
Move the pointer to its parent.
Perform a single tree rotation on the pointer and its parent.
The search is required, at some point within this sequence of operations to move the pointer to a node containing the key, and the cost of the search is the number of operations that are performed in the sequence. The total cost costA(X) for algorithm A on access sequence X is the sum of the costs of the searches for each successive key in the sequence.
As is standard in competitive analysis, the competitive ratio of an algorithm A is defined to be the maximum, over all access sequences, of the ratio of the cost for A to the best cost that any algorithm could achieve:
The dynamic optimality conjecture states that splay trees have constant competitive ratio, but this remains unproven. The geometric |
https://en.wikipedia.org/wiki/Piphilology | Piphilology comprises the creation and use of mnemonic techniques to remember many digits of the mathematical constant . The word is a play on the word "pi" itself and of the linguistic field of philology.
There are many ways to memorize , including the use of piems (a portmanteau, formed by combining pi and poem), which are poems that represent in a way such that the length of each word (in letters) represents a digit. Here is an example of a piem: "Now I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics." Notice how the first word has three letters, the second word has one, the third has four, the fourth has one, the fifth has five, and so on. In longer examples, 10-letter words are used to represent the digit zero, and this rule is extended to handle repeated digits in so-called Pilish writing. The short story "Cadaeic Cadenza" records the first 3,834 digits of in this manner, and a 10,000-word novel, Not A Wake, has been written accordingly.
However, poems prove to be inefficient for large memorizations of . Other methods include remembering patterns in the numbers (for instance, the year 1971 appears in the first fifty digits of ) and the method of loci (which has been used to memorize to 67,890 digits).
History
Until the 20th century, the number of digits of pi which mathematicians had the stamina to calculate by hand remained in the hundreds, so that memorization of all known digits at the time was possible. In 1949 a computer was used to calculate π to 2,000 places, presenting one of the earliest opportunities for a more difficult challenge.
Later computers calculated pi to extraordinary numbers of digits (2.7 trillion as of August 2010), and people began memorizing more and more of the output. The world record for the number of digits memorized has exploded since the mid-1990s, and it stood at 100,000 as of October 2006. The previous record (83,431) was set by the same person (Akira Haraguchi) on July 2, 2005 |
https://en.wikipedia.org/wiki/Non-Internet%20email%20address | A wide variety of non-Internet email address formats were used in early email systems before the ubiquity of the john.smith@example.com form used by Internet mail systems since the 1980s - and a few are still used in specialised contexts.
Single system
The earliest email addresses simply had to identify one user from another on one homogenous system, often a single host minicomputer or mainframe. They were therefore typically the user's login name on that system.
Examples of this style include:
ATS: 123
CompuServe: 432654,6564
MCI Mail: 373-1994
AOL: Steve Case
At a host
As computer systems became networked email addresses needed to be able to identify not only the user, but also which host or mail system they were on. Addresses of this type were used in a number of early email systems, including:
ARPANET: jim@washington
IBM Network Job Entry (NJE)
TSO/E TRANSMIT: user_id, node.user_id, node/user_id, nickname, distribution list name, (addressee,...)
VM SENDFILE: userid, userid AT YOURNODE, userid AT node, nickname
PROFS: userid@node
DECnet: host::user (e.g. DECWRL::WRL-TECHREPORTS)
cc:Mail: John Alexopoulos at MicroCircuits
MHS: Barry@MICROSOFT
Delivery path
Some email address schemes described the path through multiple hosts needed to deliver email. This worked well only if the first host given in the path was sufficiently well known for the sender's system to be able to contact it.
UUCP "bang path": reed!percival!bucket!lisag (example on a business card)
Hierarchical
Hierarchical addressing schemes are naturally able to expand. The modern Internet email address (e.g. john.smith@example.com), is of this type - but it was also used by a number of early systems, including:
Banyan VINES: Ed Hirsch@Faculty@Univ
Grey Book: USERID@UK.AC.CAM.ENG
FidoNET: lenz @ 2:331/113.1
Lotus Notes: Tyler Hamilton/Sales@Europe
Directory systems
In this type of system, there is no one unique address for a specific user, but instead a series of attributes, |
https://en.wikipedia.org/wiki/Emilio%20Gagliardo | Emilio Gagliardo (5 November 1930, Genoa – 15 August 2008, Genoa) was an Italian mathematician working in the field of Analysis.
Life
He did his PhD in Algebraic Geometry at the University of Genoa with Eugenio Togliatti and graduated in 1953.He then became an assistant of Guido Stampacchia and started to study partial differential equations. In 1959 he got his Habilitation and spend some time abroad with Nachman Aronszajn at the University of Kansas and with Jacques-Louis Lions in Nancy. In 1961 he became Professor in Genoa. From 1968 to 1975 he was at the University of Oregon and since 1975 at the University of Padua.
His main contributions are to the field of parabolic partial differential equations, interpolation in Banach spaces, and Sobolev spaces.
1964 was awarded the Caccioppoli Prize.
Selected works
Ulteriori proprietà di alcune classi di funzioni in più variabili, Ricerche Mat., 8, 1959, 24–52
Caratterizzazioni delle tracce sulla frontiera relative ad alcune classi di funzioni in n variabili, Rend. Sem. Mat. Univ. Padova, 27, 1957, 284–305
with Nachman Aronszajn: Interpolation spaces and interpolation methods, Ann. Mat. Pura Appl., 68, 1965, 51–117 |
https://en.wikipedia.org/wiki/Loewner%27s%20torus%20inequality | In differential geometry, Loewner's torus inequality is an inequality due to Charles Loewner. It relates the systole and the area of an arbitrary Riemannian metric on the 2-torus.
Statement
In 1949 Charles Loewner proved that every metric on the 2-torus satisfies the optimal inequality
where "sys" is its systole, i.e. least length of a noncontractible loop. The constant appearing on the right hand side is the Hermite constant in dimension 2, so that Loewner's torus inequality can be rewritten as
The inequality was first mentioned in the literature in .
Case of equality
The boundary case of equality is attained if and only if the metric is flat and homothetic to the so-called equilateral torus, i.e. torus whose group of deck transformations is precisely the hexagonal lattice spanned by the cube roots of unity in .
Alternative formulation
Given a doubly periodic metric on (e.g. an imbedding in which is invariant by a isometric action), there is a nonzero element and a point such that , where is a fundamental domain for the action, while is the Riemannian distance, namely least length of a path joining and .
Proof of Loewner's torus inequality
Loewner's torus inequality can be proved most easily by using the computational formula for the variance,
Namely, the formula is applied to the probability measure defined by the measure of the unit area flat torus in the conformal class of the given torus. For the random variable X, one takes the conformal factor of the given metric with respect to the flat one. Then the expected value E(X 2) of X 2 expresses the total area of the given metric. Meanwhile, the expected value E(X) of X can be related to the systole by using Fubini's theorem. The variance of X can then be thought of as the isosystolic defect, analogous to the isoperimetric defect of Bonnesen's inequality. This approach therefore produces the following version of Loewner's torus inequality with isosystolic defect:
where ƒ is the conform |
https://en.wikipedia.org/wiki/Lant | Lant is aged urine. The term comes from Old English , which referred to urine. Collected urine was put aside to ferment until used for its chemical content in many pre-industrial processes, such as cleaning and production.
History
Because of its ammonium content, lant was most commonly used for floor cleaning and laundry. According to early housekeeping guides, bedpans would be collected by one of the younger male servants and put away to ferment to a mild caustic before use.
In larger cottage industries, lant was used in wool-processing and as a source of saltpeter for gunpowder. In times of urgent need and in districts where these were the chief industries, the whole town was expected to contribute to its supply.
See also
Ammonia
Urine
Home remedies
Nitrogen |
https://en.wikipedia.org/wiki/The%20Geometry%20of%20Musical%20Rhythm | The Geometry of Musical Rhythm: What Makes a "Good" Rhythm Good? is a book on the mathematics of rhythms and drum beats. It was written by Godfried Toussaint, and published by Chapman & Hall/CRC in 2013 and in an expanded second edition in 2020. The Basic Library List Committee of the Mathematical Association of America has suggested its inclusion in undergraduate mathematics libraries.
Author
Godfried Toussaint (1944–2019) was a Belgian–Canadian computer scientist who worked as a professor of computer science for McGill University and New York University. His main professional expertise was in computational geometry, but he was also a jazz drummer, held a long-term interest in the mathematics of music and musical rhythm, and since 2005 held an affiliation as a researcher in the Centre for Interdisciplinary Research in Music Media and Technology in the Schulich School of Music at McGill. In 2009 he visited Harvard University as a Radcliffe Fellow in advancement of his research in musical rhythm.
Topics
In order to study rhythms mathematically, Toussaint abstracts away many of their features that are important musically, involving the sounds or strengths of the individual beats, the phasing of the beats, hierarchically-structured rhythms, or the possibility of music that changes from one rhythm to another. The information that remains describes the beats of each bar (an evenly-spaced cyclic sequence of times) as being either on-beats (times at which a beat is emphasized in the musical performance) or off-beats (times at which it is skipped or performed only weakly). This can be represented combinatorially as a necklace, an equivalence class of binary sequences under rotations, with true binary values representing on-beats and false representing off-beats. Alternatively, Toussaint uses a geometric representation as a convex polygon, the convex hull of a subset of the vertices of a regular polygon, where the vertices of the hull represent times when a beat is perform |
https://en.wikipedia.org/wiki/2-Acetyl-1-pyrroline | 2-Acetyl-1-pyrroline (2AP) is an aroma compound and flavor that gives freshly baked bread, jasmine rice and basmati rice, the herb pandan (Pandanus amaryllifolius), and bread flowers (Vallaris glabra) their customary smell. Many observers describe the smell as similar to "hot, buttered popcorn", and it is credited for lending this odor to the scent of binturong (bearcat) urine. Fresh marking fluid (MF) and urine of the tiger (Indian, Amur or Siberian) and Indian leopard also have a strong aroma due to 2AP.
2AP and its structural homolog, 6-acetyl-2,3,4,5-tetrahydropyridine of similar smell, can be formed by Maillard reactions during heating of food such as the baking of bread dough. Both compounds have odor thresholds below 0.06 ng/L.
Structure and properties
2AP is a substituted pyrroline and a cyclic imine as well as a ketone. |
https://en.wikipedia.org/wiki/Dini%20continuity | In mathematical analysis, Dini continuity is a refinement of continuity. Every Dini continuous function is continuous. Every Lipschitz continuous function is Dini continuous.
Definition
Let be a compact subset of a metric space (such as ), and let be a function from into itself. The modulus of continuity of is
The function is called Dini-continuous if
An equivalent condition is that, for any ,
where is the diameter of .
See also
Dini test — a condition similar to local Dini continuity implies convergence of a Fourier transform. |
https://en.wikipedia.org/wiki/Poincar%C3%A9%E2%80%93Birkhoff%20theorem | In symplectic topology and dynamical systems, Poincaré–Birkhoff theorem (also known as Poincaré–Birkhoff fixed point theorem and Poincaré's last geometric theorem) states that every area-preserving, orientation-preserving homeomorphism of an annulus that rotates the two boundaries in opposite directions has at least two fixed points.
History
The Poincaré–Birkhoff theorem was discovered by Henri Poincaré, who published it in a 1912 paper titled "Sur un théorème de géométrie", and proved it for some special cases. The general case was proved by George D. Birkhoff in his 1913 paper titled "Proof of Poincaré's geometric theorem". |
https://en.wikipedia.org/wiki/Girth%20%28geometry%29 | In three-dimensional geometry, the girth of a geometric object, in a certain direction, is the perimeter of its parallel projection in that direction. For instance, the girth of a unit cube in a direction parallel to one of the three coordinate axes is four: it projects to a unit square, which has four as its perimeter.
Surfaces of constant girth
The girth of a sphere in any direction equals the circumference of its equator, or of any of its great circles. More generally,
if is a surface of constant width , then every projection of is a curve of constant width, with the same width . All curves of constant width have the same perimeter, the same value as the circumference of a circle with that width (this is Barbier's theorem). Therefore, every surface of constant width is also a surface of constant girth: its girth in all directions is the same number . Hermann Minkowski proved, conversely, that every convex surface of constant girth is also a surface of constant width.
Projection versus cross-section
For a prism or cylinder, its projection in the direction parallel to its axis is the same as its cross section, so in these cases the girth also equals the perimeter of the cross section. In some application areas such as shipbuilding this alternative meaning, the perimeter of a cross section, is taken as the definition of girth.
Application
Girth is sometimes used by postal services and delivery companies as a basis for pricing. For example, Canada Post requires that an item's length plus girth not exceed a maximum allowed value. For a rectangular box, the girth is 2 * (height + width), i.e. the perimeter of a projection or cross section perpendicular to its length. |
https://en.wikipedia.org/wiki/Quadratic%20pseudo-Boolean%20optimization | Quadratic pseudo-Boolean optimisation (QPBO) is a combinatorial optimization method for quadratic pseudo-Boolean functions in the form
in the binary variables , with . If is submodular then QPBO produces a global optimum equivalently to graph cut optimization, while if contains non-submodular terms then the algorithm produces a partial solution with specific optimality properties, in both cases in polynomial time.
QPBO is a useful tool for inference on Markov random fields and conditional random fields, and has applications in computer vision problems such as image segmentation and stereo matching.
Optimization of non-submodular functions
If the coefficients of the quadratic terms satisfy the submodularity condition
then the function can be efficiently optimised with graph cut optimization. It is indeed possible to represent it with a non-negative weighted graph, and the global minimum can be found in polynomial time by computing a minimum cut of the graph, which can be computed with algorithms such as Ford–Fulkerson, Edmonds–Karp, and Boykov–Kolmogorov's.
If the function is not submodular, then the problem is NP-hard in the general case and it is not always possible to solve it exactly in polynomial time. It is possible to replace the target function with a similar but submodular approximation, e.g. by removing all non-submodular terms or replacing them with submodular approximations, but such approach is generally sub-optimal and it produces satisfying results only if the number of non-submodular terms is relatively small.
QPBO builds an extended graph, introducing a set of auxiliary variables ideally equivalent to the negation of the variables in the problem. If the nodes in the graph associated to a variable (representing the variable itself and its negation) are separated by the minimum cut of the graph in two different connected components, then the optimal value for such variable is well defined, otherwise it is not possible to infer it. Such metho |
https://en.wikipedia.org/wiki/Bohm%20diffusion | The diffusion of plasma across a magnetic field was conjectured to follow the Bohm diffusion scaling as indicated from the early plasma experiments of very lossy machines. This predicted that the rate of diffusion was linear with temperature and inversely linear with the strength of the confining magnetic field.
The rate predicted by Bohm diffusion is much higher than the rate predicted by classical diffusion, which develops from a random walk within the plasma. The classical model scaled inversely with the square of the magnetic field. If the classical model is correct, small increases in the field lead to much longer confinement times. If the Bohm model is correct, magnetically confined fusion would not be practical.
Early fusion energy machines appeared to behave according to Bohm's model, and by the 1960s there was a significant stagnation within the field. The introduction of the tokamak in 1968 was the first evidence that the Bohm model did not hold for all machines. Bohm predicts rates that are too fast for these machines, and classical too slow; studying these machines has led to the neoclassical diffusion concept.
Description
Bohm diffusion is characterized by a diffusion coefficient equal to
where B is the magnetic field strength, T is the electron gas temperature, e is the elementary charge, kB is the Boltzmann constant.
History
It was first observed in 1949 by David Bohm, E. H. S. Burhop, and Harrie Massey while studying magnetic arcs for use in isotope separation. It has since been observed that many other plasmas follow this law. Fortunately there are exceptions where the diffusion rate is lower, otherwise there would be no hope of achieving practical fusion energy. In Bohm's original work he notes that the fraction 1/16 is not exact; in particular "the exact value of [the diffusion coefficient] is uncertain within a factor of 2 or 3." Lyman Spitzer considered this fraction as a factor related to plasma instability.
Approximate derivation
Gene |
https://en.wikipedia.org/wiki/Sage%20oil | Sage oils are essential oils that come in several varieties:
Dalmatian sage oil
Also called English, Garden, and True sage oil. Made by steam distillation of Salvia officinalis partially dried leaves. Yields range from 0.5 to 1.0%. A colorless to yellow liquid with a warm camphoraceous, thujone-like odor and sharp and bitter taste. The main components of the oil are thujone (50%), camphor, pinene, and cineol.
Clary sage oil
Sometimes called muscatel. Made by steam or water distillation of Salvia sclarea flowering tops and foliage. Yields range from 0.7 to 1.5%. A pale yellow to yellow liquid with a herbaceous odor and a winelike bouquet. Produced in large quantities in France, Russia and Morocco. The oil contains linalyl acetate, linalool and other terpene alcohols (sclareol), as well as their acetates.
Spanish sage oil
Made by steam distillation of Salvia lavandulifolia leaves and twigs. A colorless to pale yellow liquid with the characteristic camphoraceous odor. Unlike Dalmatian sage oil, Spanish sage oil contains no or only traces of thujone; camphor and eucalyptol are the major components.
Greek sage oil
Made by steam distillation of Salvia triloba leaves. Grows in Greece and Turkey. Yields range from 0.25% to 4%. The oil contains camphor, thujone, and pinene, the dominant component being eucalyptol.
Judaean sage oil
Made by steam distillation of Salvia judaica leaves. The oil contains mainly cubebene and ledol. |
https://en.wikipedia.org/wiki/SENS%20Research%20Foundation | The SENS Research Foundation is a non-profit organization that does research programs and public relations work for the application of regenerative medicine to aging. It was founded in 2009, located in Mountain View, California, USA. The organization publishes its reports annually.
History
Before the foundation was founded in March 2009, the SENS research program was mainly pursued by the Methuselah Foundation, co-founded by Aubrey de Grey and David Gobel.
When the SENS rejuvenation approach was announced in the 2000s, while some biogerontologists supported the SENS program, many contended that the ultimate goals of de Grey's programme were too speculative given the state of technology and referred to it as "fantasy rather than science". By the mid-2010s, the rejuvenation approach gained traction with multiple startup companies created from SENS research findings. In 2021 Michael Greve pledged another €300 million for rejuvenation biotechnology startup companies. In 2021, Underdog Pharmaceuticals, a startup company spun out from a research program at SENS Research Foundation, was awarded an Innovation Passport from the United Kingdom Medicines and Healthcare products Regulatory Agency, which intends to streamline the approval program of promising therapies. In August 2021, Aubrey de Grey was suspended from the foundation. The CEO of the SENS Research Foundation, Jim O’Neill left in the preceding July, at the same time de Grey was suspended.
Goals
According to the organization site, its goal is to "help build the industry that will cure the diseases of aging". It funds research and uses outreach and education in order to expedite the various regenerative medicine research programs that go together to make the SENS project. The foundation also conducts its own student program SRF Education.
Research
Research programs
The SENS Research Foundation (SRF) pursues research projects that correspond to the seven categories of cellular damage due to aging:
Research c |
https://en.wikipedia.org/wiki/Packet%20over%20SONET/SDH | Packet over SONET/SDH, abbreviated POS, is a communications protocol for transmitting packets in the form of the Point to Point Protocol (PPP) over SDH or SONET, which are both standard protocols for communicating digital information using lasers or light emitting diodes (LEDs) over optical fibre at high line rates. POS is defined by RFC 2615 as PPP over SONET/SDH. PPP is the Point to Point Protocol that was designed as a standard method of communicating over point-to-point links. Since SONET/SDH uses point-to-point circuits, PPP is well suited for use over these links. Scrambling is performed during insertion of the PPP packets into the SONET/SDH frame to solve various security attacks including denial-of-service attacks and the imitation of SONET/SDH alarms. This modification was justified as cost-effective because the scrambling algorithm was already used by the standard used to transport ATM cells over SONET/SDH. However, scrambling can optionally be disabled to allow a node to be compatible with another node that uses the now obsoleted RFC 1619 version of Packet over SONET/SDH which lacks the scrambler.
Applications of POS
The most important application of POS is to support sending of IP packets across wide area networks. Large amounts of traffic on the Internet are carried over POS links.
POS is also one of the link layers used by the Resilient Packet Ring standard known as IEEE 802.17.
History of POS
Cisco was involved in making POS an important wide area network protocol. PMC-Sierra produced an important series of early semiconductor devices which
implemented POS.
Details about the name "POS"
POS (packet over SONET) is a double-nested abbreviation. The S represents "SONET/SDH", which itself stands for "Synchronous Optical Network/Synchronous Digital Hierarchy".
Given this information, POS technically stands for "Packet over Synchronous Optical Network/Synchronous Digital Hierarchy".
Complementary Interfaces
The System Packet Interface series of stand |
https://en.wikipedia.org/wiki/Emphasis%20mark | The emphasis mark or emphasis dot is a typographic marking used in some East Asian languages to indicate emphasis. The markings takes in many forms like, a dot or a bullet, a circle, or a triangle. It was used more traditionally, but nowadays, with technology, quotations or changing of font style prevails.
In Chinese
In China and Hong Kong, the emphasis mark () is used in textbooks and teaching materials. It is centred under each character highlighted in the horizontal texts, and centred to the right of each character in the vertical texts.
In Japanese
In Japan, the emphasis mark ( or ) is usually a dot or a sesame dot and is centred above each character in the horizontal texts and to the right of each character in the vertical texts.
It is not unusual for kenten and ruby to concur on the same side of the main text (usually above or to the right), but this feature has not been possible with CSS.
In Korean
In South Korea, the emphasis mark ( ) usually rules as a dot or circle centred above the characters in the horizontal texts and to the right of the characters in the vertical texts.
Examples:
using the CSS property:
한글의 본 이름은 훈민정음이다.
중요한 것은 왜 사느냐가 아니라 어떻게 사느냐 하는 문제이다.
using positioned characters: :
한글의 본 이름은 •훈•민•정•음이다.
중요한 것은 ◦왜 ◦사◦느◦냐◦가 아니라 ◦어◦떻◦게 ◦사◦느◦냐 하는 문제이다.
Characters
Apart from any single character, the following characters are used as emphasis marks in some implementations.
See also
Chinese punctuation
Japanese punctuation
Korean punctuation |
https://en.wikipedia.org/wiki/Bredt%27s%20rule | In organic chemistry, Bredt's rule is an empirical observation that states that a double bond cannot be placed at the bridgehead of a bridged ring system, unless the rings are large enough. The rule is named after Julius Bredt, who first discussed it in 1902 and codified it in 1924. It primarily relates to bridgeheads with carbon-carbon and carbon-nitrogen double bonds.
For example, two of the following isomers of norbornene violate Bredt's rule, which makes them too unstable to prepare:
In the figure, the bridgehead atoms involved in Bredt's rule violation are highlighted in red.
Bredt's rule is a consequence of the fact that having a double bond on a bridgehead, carbons from which three bonds radiate and which the rings share a single covalent bond, would be equivalent to having a trans double bond on a ring, which is not stable for small rings (fewer than eight atoms) due to a combination of ring strain, and angle strain (nonplanar alkene). The p orbitals of the bridgehead atom and adjacent atoms are orthogonal and thus are not aligned properly for the formation of pi bonds. Fawcett quantified the rule by defining S as the number of non-bridgehead atoms in a ring system, and postulated that stability required S ≥ 9 in bicyclic systems and S ≥ 11 in tricyclic systems. There has been an active research program to seek compounds inconsistent with the rule, and for bicyclic systems a limit of S ≥ 7 is now established with several such compounds having been prepared. The above norbornene system has S = 5 and so they are not preparable.
Bredt's rule can be useful for predicting which isomer is obtained from an elimination reaction in a bridged ring system. It can also be applied to reaction mechanisms that go via carbocations and, to a lesser degree, via free radicals, because these intermediates, like carbon atoms involved in a double bond, prefer to have a planar geometry with 120 degree angles and sp2 hybridization. The rule also allows the rationalisation |
https://en.wikipedia.org/wiki/Pseudomonas%20virus%2042 | Pseudomonas virus 42, formerly Pseudomonas phage 42, is a bacteriophage known to infect Pseudomonas bacteria. |
https://en.wikipedia.org/wiki/DNA%20re-replication | DNA re-replication (or simply rereplication) is an undesirable and possibly fatal occurrence in eukaryotic cells in which the genome is replicated more than once per cell cycle. Rereplication is believed to lead to genomic instability and has been implicated in the pathologies of a variety of human cancers. To prevent rereplication, eukaryotic cells have evolved multiple, overlapping mechanisms to inhibit chromosomal DNA from being partially or fully rereplicated in a given cell cycle. These control mechanisms rely on cyclin-dependent kinase (CDK) activity. DNA replication control mechanisms cooperate to prevent the relicensing of replication origins and to activate cell cycle and DNA damage checkpoints. DNA rereplication must be strictly regulated to ensure that genomic information is faithfully transmitted through successive generations.
Initiating replication at origins
Replication of DNA always begins at an origin of replication. In yeast, the origins contain autonomously replicating sequences (ARS), distributed throughout the chromosome about 30 kb from each other. They allow replication of DNA wherever they are placed. Each one is 100-200 bp long, and the A element is one of the most conserved stretches. Along with other conserved B elements, they form the section where the ORCs assemble to begin replication. The repetition of these sequences may be the most important to origin recognition.
In animal cells, replication origins may seem to be randomly placed throughout the chromosome, sometimes even acting as ARSs, but local chromatin structure plays a large role in determining where replication will occur. The replication origins are not distributed evenly throughout the chromosome. Replicon clusters, containing 20-80 origins per cluster, are activated at the same time during S phase. Although they are all activated during S phase, heterochromatin tends to be replicated in late S phase, as they are more difficult to access than euchromatin. Epigenetic fac |
https://en.wikipedia.org/wiki/REG1 | REG1 is an anticoagulation system cosisting of two drugs: pegnivacogin, a single-stranded 31-nucleotide aptamer that binds and inhibits Factor IXa, and anivamersen, a complementary sequence reversal 15-nucleotide control agent. REG1 mechanism of action It involves inhibition of Factor IXa.
REG1 is being developed for use in patients undergoing percutaneous coronary intervention and the treatment of acute coronary syndrome. REG1 is associated with severe allergic reactions. In the phase 2b RADAR trial, 12 allergic-like reactions occurred shortly after administration of pegnivacogin in three patients with histories of allergy.
In one clinical trial, it was found that there was no evidence that REG1 reduced ischaemic events or bleeding compared with bivalirudin. |
https://en.wikipedia.org/wiki/Clinical%20biophysics | Clinical biophysics is that branch of medical science that studies the action process and the effects of non-ionising physical energies utilised for therapeutic purposes.
Physical energy can be applied for diagnostic or therapeutic aims.
The principle on which clinical biophysics is based are represented by the recognizability and the specificity of the physical signal applied:
recognizability: the capacity of the biological target to recognise the presence of the physical energy: this aspect becomes more important with the lowering of the energy applied.
specificity: the capacity of the physical agent applied to the biological target to obtain a response depending on its physical characteristics: frequency, length, energy, etc. The effects do not necessarily depend on the quantity of energy applied to the biological target.
Definition
Several papers show that the response of a biological system when exposed to non-ionizing physical stimuli is not necessarily dependent on the amount of energy applied.
Specific combinations of amplitude, frequency and waveform may trigger the most intense response. For example, cell proliferation or activation of metabolic pathways.
This has been demonstrated for:
a) mechanical strains directly applied to the cells or tissue;
b) mechanical energy applied by ultrasound;
c) electromagnetic field exposure;
d) electric field exposure.
Several pre-clinical experiences have laid the foundation to identify exposure conditions that may be used in humans to treat diseases or to promote tissue healing.
The identification of the best parameters to apply in any particular circumstance is the current goal of research activities in the field.
Medical applications
Orthopaedics
PEMF
LIPUS
CCEF
Direct current
Neurology
Plastic surgery
Oncology |
https://en.wikipedia.org/wiki/Fish%20doorbell | A fish doorbell (Dutch: visdeurbel) is a system that allows fish to pass through a closed sluice gate through crowdsourced input when fish are present. The Utrecht Visdeurbel uses a livestreamed underwater camera that allows users to press a doorbell button to notify the lock operator that there are fish swimming in the gracht, and that the lock should be opened. It is designed to aid in seasonal fish migration, as an alternative to a physical fish ladder.
Usage
It was deployed for the first time in Utrecht in March 2021, at the Weerdsluis on the Oudegracht. In the first two weeks, it was used 23,000 times. It was disabled in June, but has since been reinstated at visdeurbel.nl. |
https://en.wikipedia.org/wiki/Virtually%20Live | Virtually Live is a patented media method and system that uses visualization technology and telemetry to enable a fan experience of virtually attending live events and interact with them across multiple devices and platforms, creating an immersive and socially interactive experience.
Features
The Virtually Live media method and system allows for the real time visualization of live data for the purpose of producing a live CGI stream with very low latency. The inventors’ concept was to recreate live sporting and entertainment events in hyper-realistic scenery and allow users to participate in real time rather than just passively watch. Virtually Live is compatible with HTC Vive and Oculus Rift.
Development and patents
Jamil El-Imad and Jesús Hormigo Cebolla conceived the Virtually Live method and system in 2008. Their idea was to create a media method that would take all the active elements of an event and transpose it in real time to a platform whereby people could feel a ‘sense of presence’ in the event. The media method would “capture all the telemetry and motion of an event, place it in a simulator, then bring the fans in to experience it.” Their technology was invented and patented globally from 2009 onwards.
In 2010, the European Patent Office granted patents across 38 designated states: Albania, Austria, Belgium, Bosnia & Herzegovina, Bulgaria, Switzerland/Liechtenstein, Cyprus, Czech Republic, Germany, Denmark, Estonia, Spain, Finland, France, the United Kingdom, Greece, Croatia, Hungary, Ireland, Iceland, Italy, Lithuania, Luxembourg, Latvia, Monaco, Macedonia, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Sweden, Slovenia, Slovakia, and Turkey. In 2011, the patent was granted in South Africa. In 2012, patents were granted in Singapore and the USA.
Applications in sports
In 2016, the first proof of concept was with the Scottish Professional Football League which used the platform to test a live football broadcast in virtual reality at |
https://en.wikipedia.org/wiki/Joseph%20Lipman | Joseph Lipman (born June 15, 1938) is a Canadian-American mathematician, working in algebraic geometry.
Lipman graduated from the University of Toronto with a Bachelor's degree in 1960 and then went to Harvard University, receiving his master's degree in 1961. He then earned a Ph.D. there in 1965 under the supervision of Oscar Zariski. In 1965 he was an assistant professor at Queen's University in Kingston and in 1966 was an assistant professor at the Purdue University, where he became professor in 1971. From 1987 to 1992, there, he was head of the mathematics department. He was a member of the MSRI and visiting scholar at the University of Cambridge and the University of Nice and a visiting professor at the Columbia University and Harvard University.
He specializes in singularity theory in algebraic geometry.
In 1958, while studying at the University of Toronto, he became a Putnam Fellow both in the spring and fall William Lowell Putnam Mathematical Competitions. In 1982 he received the Jeffery–Williams Prize. He is a fellow of the American Mathematical Society.
Writings
Collected Papers of Joseph Lipman. Queen's Papers in Pure and Applied Mathematics, vol. 117, Queen's University Press, Kingston, Ontario, 2000.
Editor with Herwig Hauser, Frans Oort, Adolfo Quirós: Resolution of singularities. A research textbook in tribute to Oscar Zariski. Birkhäuser, Basel 2000, . (Progress in Mathematics. volume 181.) |
https://en.wikipedia.org/wiki/Chile%20ayuda%20a%20Chile | Chile ayuda a Chile (Chile helps Chile) was a charity telethon being held from March 5 to March 6, 2010. The event was broadcast from Teatro Teletón in Santiago, Chile.
The telethon's aim was to raise money to help those affected by the 2010 Chile earthquake that struck the central-southern Chile on 27 February of that year. The event was organized by the Telethon Foundation and the Government of Chile, in coordination with Hogar de Cristo, Un Techo para Chile, the Fundación para la Superación de la Pobreza and Caritas, and was broadcast by all television stations affiliated with National Association of Television (Anatel) on national TV. The goal of the charity was to raise $15,000,000,000 for the construction of 30,000 emergency homes ("mediaguas") in the disaster area. Donations were to be deposited in account N° 2702 at Banco de Chile and Banco Santander.
During the event, over 46 billion pesos (90 million US dollars) were collected, and on March 9, 2010, Mario Kreutzberger said the event raised in total cash and goods over $50,000,000,000 (96.5 million dollars), thus surpassing the money raised by the Hope for Haiti Now event held in the United States in relief of the also earthquake-struck Caribbean country earlier that year.
Background
TV host Mario Kreutzberger, better known as Don Francisco, has hosted a series of television campaigns since 1978, when he organized the first version of the Telethon. In 1985, during the earthquake that hit Chile on 3 March that year, Kreutzberger organized a campaign, broadcast on Canal 13 called Chile helps Chile, which, after 30 hours of non-stop broadcasting, managed to fund hundreds of trucks with supplies for victims. The event was repeated in later years, after other natural disasters such as flash floods, earthquakes, volcanic eruptions and others.
On February 27, 2010, the earthquake devastated central and southern Chile, with its epicentre in Cobquecura, Biobío Region, with a magnitude of 8.8 MW. The earthquake |
https://en.wikipedia.org/wiki/List%20of%20PlayStation%20applications | This is a list of PlayStation applications currently planned or released via the PlayStation Network.
Applications
Mobile & PC
Entertainment services
Assorted
Virtual Reality
Archaic
License regions |
https://en.wikipedia.org/wiki/Active%20chromatin%20sequence | An active chromatin sequence (ACS) is a region of DNA in a eukaryotic chromosome in which histone modifications such as acetylation lead to exposure of the DNA sequence thus allowing binding of transcription factors and transcription to take place. Active chromatin may also be called euchromatin. ACSs may occur in non-expressed gene regions which are assumed to be "poised" for transcription. The sequence once exposed often contains a promoter to begin transcription. At this site acetylation or methylation can take place causing a conformational change to the chromatin. At the active chromatin sequence site deacetylation can caused the gene to be repressed if not being expressed.
See also
Chromatin |
https://en.wikipedia.org/wiki/UKFast | UKFast.Net Limited (trading as UKFast) is a business-to-business internet hosting company based in Manchester, UK. It is principally known for managed hosting, cloud services, and co-location. The business owns and operates its data centre complex in Trafford Park, Manchester.
As of 2019 the company employs more than 365 people and in 2018 it achieved revenues of £53.9m.
It provides services to more than 5,000 clients including the NHS, the Ministry of Defence and the Cabinet Office.
As of June 2022, UKFast.Net Limited and ANS Group Limited which are both controlled by private equity group Inflexion have merged.
Company history
UKFast was founded in September 1999 by Welsh businessman Lawrence Jones and his wife Gail Jones.
In 2007, the company moved its head office to the 28th floor of City Tower, Manchester. It acquired further space on the 16th floor, before moving in 2013 to a campus at 1 Archway in the Birley Fields area of Hulme, Manchester.
In 2013 the firm launched eCloud, a range of cloud hosting services whose hardware infrastructure reportedly cost £12 million to build. In that year, the business turned over £23.4m.
For the year ending 31 December 2014, UKFast reported a 24 per cent turnover increase from £23.4m to £28.9m. Between 2011 and 2015, UKFast invested more than £25m into capital expenditure projects including the development of four data centres and the flagship UKFast Campus.
In 2013 UKFast opened an office in Glasgow and in 2015 opened a further office in London.
In 2014, Founder Lawrence Jones rejected a reported £200m takeover bid amidst a trend of web hosting consolidation, citing that the business was still growing.
In 2016, UKFast doubled the size of its HQ by securing a further 40,000 sq. ft. space at 3 Archway, Birley Fields, adjacent to its existing building.
In 2018 a 30% stake of UKFast was sold to private equity firm Inflexion for around £120 million
On 31 October 2019, CRN reported "Lawrence Jones quits UKFast followin |
https://en.wikipedia.org/wiki/Frequency-locked%20loop | A frequency-lock, or frequency-locked loop (FLL), is an electronic control system that generates a signal that is locked to the frequency of an input or "reference" signal. This circuit compares the frequency of a controlled oscillator to the reference, automatically raising or lowering the frequency of the oscillator until its frequency (but not necessarily its phase) is matched to that of the reference.
A frequency-locked loop is an example of a control system using negative feedback. Frequency-lock loops are used in radio, telecommunications, computers and other electronic applications to generate stable frequencies, or to recover a signal from a noisy communication channel.
See also
Phase-locked loop |
https://en.wikipedia.org/wiki/Meissel%E2%80%93Mertens%20constant | The Meissel–Mertens constant (named after Ernst Meissel and Franz Mertens), also referred to as Mertens constant, Kronecker's constant, Hadamard–de la Vallée-Poussin constant or the prime reciprocal constant, is a mathematical constant in number theory, defined as the limiting difference between the harmonic series summed only over the primes and the natural logarithm of the natural logarithm:
Here γ is the Euler–Mascheroni constant, which has an analogous definition involving a sum over all integers (not just the primes).
The value of M is approximately
M ≈ 0.2614972128476427837554268386086958590516... .
Mertens' second theorem establishes that the limit exists.
The fact that there are two logarithms (log of a log) in the limit for the Meissel–Mertens constant may be thought of as a consequence of the combination of the prime number theorem and the limit of the Euler–Mascheroni constant.
In popular culture
The Meissel-Mertens constant was used by Google when bidding in the Nortel patent auction. Google posted three bids based on mathematical numbers: $1,902,160,540 (Brun's constant), $2,614,972,128 (Meissel–Mertens constant), and $3.14159 billion (π).
See also
Divergence of the sum of the reciprocals of the primes
Prime zeta function |
https://en.wikipedia.org/wiki/Bathypelagic%20zone | The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above and the abyssopelagic below. The bathypelagic is also known as the midnight zone because of the lack of sunlight; this feature does not allow for photosynthesis-driven primary production, preventing growth of phytoplankton or aquatic plants. Although larger by volume than the photic zone, human knowledge of the bathypelagic zone remains limited by ability to explore the deep ocean.
Physical characteristics
The bathypelagic zone is characterized by a nearly constant temperature of approximately and a salinity range of 33-35 g/kg. This region has little to no light because sunlight does not reach this deep in the ocean and bioluminescence is limited. The hydrostatic pressure in this zone ranges from 100-400 atmospheres (atm) due to the increase of 1 atm for every 10 m depth. It is believed that these conditions have been consistent for the past 8000 years.
This ocean depth spans from the edge of the continental shelf down to the top of the abyssal zone, and along continental slope depths. The bathymetry of the bathypelagic zone consists of limited areas where the seafloor is in this depth range along the deepest parts of the continental margins, as well as seamounts and mid-ocean ridges. The continental slopes are mostly made up of accumulated sediment, while seamounts and mid-ocean ridges contain large areas of hard substrate that provide habitats for bathypelagic fishes and benthic invertebrates. Although currents at these depths are very slow, the topography of seamounts interrupts the currents and creates eddies that retain plankton in the seamount region, thus increasing fauna nearby as well
Hydrothermal vents are also a common feature in some areas of the bathypelagic zone and are primarily formed from the spreading of Earth's tectonic plates at mid-ocean ridges. A |
https://en.wikipedia.org/wiki/National%20Agency%20for%20Food%20and%20Drug%20Administration%20and%20Control | The National Agency for Food and Drug Administration and Control (NAFDAC) is a Nigerian federal agency under the Federal Ministry of Health that is responsible for regulating and controlling the manufacture, importation, exportation, advertisement, distribution, sale, and use of food, drugs, cosmetics, medical devices, chemicals, and packaged water.
The agency is headed by Dr. Monica Eimunjeze in an acting capacity on November 12, 2022, according to an internal memo dated November 17, 2022, signed by Oboli A.U and copied to all Directors at the agency, following the expiration of Prof Mojisola Adeyeye. She was appointed on 12 November 2022 by the President of the Federal Republic of Nigeria as the acting Director-General of the National Agency for Food and Drug Administration and Control (NAFDAC).
Formation
The organization was established to counter illicit and counterfeit products in Nigeria in 1993 under the country's health and safety law.
Adulterated and counterfeit drugs are a problem in Nigeria. In one 1989 incident, over 150 children died as a result of paracetamol syrup containing diethylene glycol. The problem of fake drugs was so severe that neighboring countries such as Ghana and Sierra Leone officially banned the sale of drugs, foods, and beverages products made in Nigeria.
Such problems led to the establishment of NAFDAC, with the goal of eliminating counterfeit pharmaceuticals, foods, and beverages products that are not manufactured in Nigeria and ensuring that available medications are safe and effective.
The formation of NAFDAC was inspired by a 1988 World Health Assembly resolution requesting countries' help in combating the global health threat posed by counterfeit pharmaceuticals.
In December 1992, NAFDAC's first governing council was formed. The council was chaired by Tanimu Saulawa. In January 1993, supporting legislation was approved as Legislative Decree No. 15 of 1993. On January 1, 1994, NAFDAC was officially established as a “parast |
https://en.wikipedia.org/wiki/Chemical%20potential | In thermodynamics, the chemical potential of a species is the energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition. The chemical potential of a species in a mixture is defined as the rate of change of free energy of a thermodynamic system with respect to the change in the number of atoms or molecules of the species that are added to the system. Thus, it is the partial derivative of the free energy with respect to the amount of the species, all other species' concentrations in the mixture remaining constant. When both temperature and pressure are held constant, and the number of particles is expressed in moles, the chemical potential is the partial molar Gibbs free energy. At chemical equilibrium or in phase equilibrium, the total sum of the product of chemical potentials and stoichiometric coefficients is zero, as the free energy is at a minimum. In a system in diffusion equilibrium, the chemical potential of any chemical species is uniformly the same everywhere throughout the system.
In semiconductor physics, the chemical potential of a system of electrons at zero absolute temperature is known as the Fermi level.
Overview
Particles tend to move from higher chemical potential to lower chemical potential because this reduces the free energy. In this way, chemical potential is a generalization of "potentials" in physics such as gravitational potential. When a ball rolls down a hill, it is moving from a higher gravitational potential (higher internal energy thus higher potential for work) to a lower gravitational potential (lower internal energy). In the same way, as molecules move, react, dissolve, melt, etc., they will always tend naturally to go from a higher chemical potential to a lower one, changing the particle number, which is the conjugate variable to chemical potential.
A simple example is a system of dilute molecules diffusing in a homogeneous environment. In |
https://en.wikipedia.org/wiki/3D%20Virtual%20Creature%20Evolution | 3D Virtual Creature Evolution, abbreviated to 3DVCE, is an artificial evolution simulation program created by Lee Graham. Its purpose is to visualize and research common themes in body plans and strategies to achieve a fitness function of the artificial organisms generated and maintained by the system in their given environment. The program was inspired by Karl Sims’ 1994 artificial evolution program, Evolved Virtual Creatures. The program is run through volunteers who download the program from the home website and return information from completed simulations. As of March 4, 2013, it is available to download on Windows, MacOS, and in some cases Linux.
Settings
3DVCE uses evolutionary algorithms to simulate evolution. The user sets the body plan restrictions (maximum number of segment types, branching segments’ length and depth limits, and size limits) and whether fitness score is scaled in relation to size. Limb interpenetration is also an option. Reproduction / population settings include the size of each population and their run time (how long each individual has to attain a fitness score), percentage of individuals who get to reproduce (tournament size), what percentage sexually or asexually reproduce, and selection type is then determined. Crossover rate determines what percentage of an individual is created via crossover of parents and mutation. Mutation rate in body and brain is then determined. Specific mathematical operations and values can be attributed to the creature’s brain as well.
Fitness function is then determined. Artificial organisms’ fitness score is determined by how well they achieve their fitness goal within their evaluation time. Fitness functions include distance traveled, maximum height, average height, “TOG” (determined by amount of time creature is in contact with ground), and “Sphere” (determined by creature’s ability to catch and hold spheres). These goals are not individualized and can be set to specific strengths (from zero, as not |
https://en.wikipedia.org/wiki/Great%20Filter | The Great Filter is the idea that in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. The Great Filter is one possible resolution of the Fermi paradox.
The concept originates in Robin Hanson's argument that the failure to find any extraterrestrial civilizations in the observable universe implies that something is wrong with one or more of the arguments (from various scientific disciplines) that the appearance of advanced intelligent life is probable; this observation is conceptualized in terms of a "Great Filter" which acts to reduce the great number of sites where intelligent life might arise to the tiny number of intelligent species with advanced civilizations actually observed (currently just one: human). This probability threshold, which could lie in the past or following human extinction, might work as a barrier to the evolution of intelligent life, or as a high probability of self-destruction. The main conclusion of this argument is that the easier it was for life to evolve to the present stage, the bleaker the future chances of humanity probably are.
The idea was first proposed in an online essay titled "The Great Filter – Are We Almost Past It?", written by economist Robin Hanson. The first version was written in August 1996 and the article . Hanson's formulation has received recognition in several published sources discussing the Fermi paradox and its implications.
Main argument
Fermi paradox
There is no reliable evidence that aliens have visited Earth; we have observed no intelligent extraterrestrial life with current technology, nor has SETI found any transmissions from other civilizations. The Universe, apart from the Earth, seems "dead"; Hanson states:
Our planet and solar system, however, don't look substantially colonized by advanced competitive life from the stars, a |
https://en.wikipedia.org/wiki/Per%20sign | The per sign is a rare symbol used to indicate a ratio. In English, it can replace the word "per" in phrases such as miles per hour ("miles ⅌ hour").
Unicode
The Unicode code point is . The symbol does not appear in the ASCII set.
See also
Wiktionary's entry on the symbol |
https://en.wikipedia.org/wiki/Associated%20bundle | In mathematics, the theory of fiber bundles with a structure group (a topological group) allows an operation of creating an associated bundle, in which the typical fiber of a bundle changes from to , which are both topological spaces with a group action of . For a fiber bundle F with structure group G, the transition functions of the fiber (i.e., the cocycle) in an overlap of two coordinate systems Uα and Uβ are given as a G-valued function gαβ on Uα∩Uβ. One may then construct a fiber bundle F′ as a new fiber bundle having the same transition functions, but possibly a different fiber.
An example
A simple case comes with the Möbius strip, for which is the cyclic group of order 2, . We can take as any of: the real number line , the interval , the real number line less the point 0, or the two-point set . The action of on these (the non-identity element acting as in each case) is comparable, in an intuitive sense. We could say that more formally in terms of gluing two rectangles and together: what we really need is the data to identify to itself directly at one end, and with the twist over at the other end. This data can be written down as a patching function, with values in G. The associated bundle construction is just the observation that this data does just as well for as for .
Construction
In general it is enough to explain the transition from a bundle with fiber , on which acts, to the associated principal bundle (namely the bundle where the fiber is , considered to act by translation on itself). For then we can go from to , via the principal bundle. Details in terms of data for an open covering are given as a case of descent.
This section is organized as follows. We first introduce the general procedure for producing an associated bundle, with specified fibre, from a given fibre bundle. This then specializes to the case when the specified fibre is a principal homogeneous space for the left action of the group on itself, yielding the associated |
https://en.wikipedia.org/wiki/Count-distinct%20problem | In computer science, the count-distinct problem
(also known in applied mathematics as the cardinality estimation problem) is the problem of finding the number of distinct elements in a data stream with repeated elements.
This is a well-known problem with numerous applications. The elements might represent IP addresses of packets passing through a router, unique visitors to a web site, elements in a large database, motifs in a DNA sequence, or elements of RFID/sensor networks.
Formal definition
Instance: Consider a stream of elements with repetitions, and an integer . Let denote the number of distinct elements in the stream, represented as , where .
Objective: Find an estimate of using only storage units, where .
An example of an instance for the cardinality estimation problem is the stream: . For this instance, .
Naive solution
The naive solution to the problem is as follows:
Initialize a counter, , to zero,
Initialize an efficient dictionary data structure, , such as hash table or search tree in which insertion and membership can be performed quickly.
, a membership query is issued.
Increase by one,
Otherwise do nothing.
As long as the number of distinct elements is not too big, fits in main memory and an exact answer can be retrieved.
However, this approach does not scale for bounded storage, or if the computation performed for each element should be minimized. In such a case, several streaming algorithms have been proposed that use a fixed number of storage units.
HyperLogLog algorithm
Streaming algorithms
To handle the bounded storage constraint, streaming algorithms use a randomization to produce a non-exact estimation of the distinct number of elements, .
State-of-the-art estimators hash every element into a low-dimensional data sketch using a hash function, .
The different techniques can be classified according to the data sketches they store.
Min/max sketches
Min/max sketches store only |
https://en.wikipedia.org/wiki/Consumer%20Product%20Information%20Database | The Consumer Product Information Database (CPID), former Household Products Database, is a collection of information about chemical ingredients in a variety of household products marketed in the United States.
Description
The Consumer Health Product Database is a web-based application that allows the public to search for specific products or specific chemical ingredients. It is a collection of publicly available information, mostly from product labels and Safety Data Sheets (former MSDS) provided by the product's manufacturer. It does not cover products whose ingredients are proprietary.
As of 2021, the collection includes more than 23,000 products. The preponderance of these products are marketed for home use in the United States, although some are for commercial settings and some are for customers in European countries. It does not cover food or medicines. It is maintained by DeLima Associates and receives funding from the National Institute of Environmental Health Sciences, part of the United States National Institutes of Health.
History
The Consumer Product Information Database was initiated by DeLima Associates in 1994. By 2010, it was publicly available on DeLima's web site.
The Household Products Database, or Household Products Safety Database (HPD) for several years provided access to the CPID. The HPD was hosted on the National Library of Medicine's web site and the content was licensed from DeLima Associates. It was initially compiled in 1995, although some sources describe it as being launched in 2003. The National Library of Medicine announced the Household Products Database would be retired in December 2019, and instead directed users to the CPID web site.
See also
Environmental Working Group, which maintains a database of ingredients of cosmetics
DailyMed, drug labels in the USA |
https://en.wikipedia.org/wiki/Ascomycota | Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus" (), a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens (loosely termed "ascolichens") such as Cladonia belong to the Ascomycota.
Ascomycota is a monophyletic group (it contains all descendants of one common ancestor). Previously placed in the Deuteromycota along with asexual species from other fungal taxa, asexual (or anamorphic) ascomycetes are now identified and classified based on morphological or physiological similarities to ascus-bearing taxa, and by phylogenetic analyses of DNA sequences.
The ascomycetes are of particular use to humans as sources of medicinally important compounds, such as antibiotics, for fermenting bread, alcoholic beverages and cheese. Penicillium species on cheeses and those producing antibiotics for treating bacterial infectious diseases are examples of ascomycetes.
Many ascomycetes are pathogens, both of animals, including humans, and of plants. Examples of ascomycetes that can cause infections in humans include Candida albicans, Aspergillus niger and several tens of species that cause skin infections. The many plant-pathogenic ascomycetes include apple scab, rice blast, the ergot fungi, black knot, and the powdery mildews. Another pathogenic ascomycete is Cordyceps. Cordyceps are parasites of insects and other arthropods. They are entomopathogenic fungi, which means the fungi kills or severely injures the |
https://en.wikipedia.org/wiki/International%20Society%20for%20Cerebral%20Blood%20Flow%20%26%20Metabolism | The International Society for Cerebral Blood Flow & Metabolism is a professional society based in Rockville, Maryland for physicians and scientists focused on cerebrovascular function.
History
Technical improvements in the study of cerebral blood flow pioneered by Niels Lassen and David Ingvar in the mid-twentieth century drove demand for meetings dedicated to the discipline. In 1965, the first regional Cerebral Blood Flow (rCBF) symposium was held in Lund, Sweden. In March 1980, following discussions between Bo K. Siesjö and Louis Sokoloff, a steering committee society was formed, including Sokoloff, Siesjö, Konstantin A. Hossman, Igor Klatzo, Eric Mackenzie, Marcus Raichle, MartinReivich, and Fred Plum. The International Society for Cerebral Blood Flow & Metabolism was first announced at the 2021 rCBF meeting in St. Louis, Missouri.
Annual meeting
ISCBFM holds an annual meeting called Brain & Brain Pet. The biannual meeting is held in cities throughout the world, with the 2022 meeting taking place in Glasgow.
Publishing
The Journal of Cerebral Blood Flow & Metabolism has been an important element of the ISCFBM since the organization's founding. Additionally, ISCFBM has published a newsletter titled The Organ since 1990. |
https://en.wikipedia.org/wiki/Metallomesogen | Metallomesogens are metal complexes that exhibit liquid crystalline behavior. Thus, they adopt ordered structures in the molten phase, e.g. smectic and nematic phases. The dominant interactions responsible for their phase behavior are the nonbonding contacts between organic substituents. Two early classes of such materials are based on substituted ferrocenes and dithiolene complexes; more recent work shows that alkoxystilbazoles have similar utility. |
https://en.wikipedia.org/wiki/Quantum%20groupoid | In mathematics, a quantum groupoid is any of a number of notions in noncommutative geometry analogous to the notion of groupoid. In usual geometry, the information of a groupoid can be contained in its monoidal category of representations (by a version of Tannaka–Krein duality), in its groupoid algebra or in the commutative Hopf algebroid of functions on the groupoid. Thus formalisms trying to capture quantum groupoids include certain classes of (autonomous) monoidal categories, Hopf algebroids etc. |
https://en.wikipedia.org/wiki/Pseudolocalization | Pseudolocalization (or pseudo-localization) is a software testing method used for testing internationalization aspects of software. Instead of translating the text of the software into a foreign language, as in the process of localization, the textual elements of an application are replaced with an altered version of the original language. For example, instead of "Account Settings", the text may be altered to display as "!!! Àççôûñţ Šéţţîñĝš !!!".
These specific alterations make the original words appear readable, but include the most problematic characteristics of the world's languages: varying length of text or characters, language direction, fit into the interface and so on.
Localization process
Traditionally, localization of software is independent of the software development process. In a typical scenario, software would be built and tested in one base language (such as English), with any localizable elements being extracted into external resources. Those resources are handed off to a localization team for translation into different target languages. The problem with this approach is that many subtle software bugs may be found during the process of localization, when it is too late (or more likely, too expensive) to fix them.
The types of problems that can arise during localization involve differences in how written text appears in different languages. These problems include:
Translated text that is significantly longer than the source language, and does not fit within the UI constraints, or which causes text breaks at awkward positions.
Font glyphs that are significantly larger than, or possess diacritic marks not found in, the source language, and which may be cut off vertically.
Languages for which the reading order is not left-to-right, which is especially problematic for user input.
Application code that assumes all characters fit into a limited character set, such as ASCII or ANSI, which can produce actual logic bugs if left uncaught.
In addit |
https://en.wikipedia.org/wiki/Kolmogorov%20structure%20function | In 1973, Andrey Kolmogorov proposed a non-probabilistic approach to statistics and model selection. Let each datum be a finite binary string and a model be a finite set of binary strings. Consider model classes consisting of models of given maximal Kolmogorov complexity.
The Kolmogorov structure function of an individual data string expresses the relation between the complexity level constraint on a model class and the least log-cardinality of a model in the class containing the data. The structure function determines all stochastic properties of the individual data string: for every constrained model class it determines the individual best-fitting model in the class irrespective of whether the true model is in the model class considered or not. In the classical case we talk about a set of data with a probability distribution, and the properties are those of the expectations. In contrast, here we deal with individual data strings and the properties of the individual string focused on. In this setting, a property holds with certainty rather than with high probability as in the classical case. The Kolmogorov structure function precisely quantifies the goodness-of-fit of an individual model with respect to individual data.
The Kolmogorov structure function is used in the algorithmic information theory, also known as the theory of Kolmogorov complexity, for describing the structure of a string by use of models of increasing complexity.
Kolmogorov's definition
The structure function was originally proposed by Kolmogorov in 1973 at a Soviet Information Theory symposium in Tallinn, but these results were not published p. 182. But the results were announced in in 1974, the only written record by Kolmogorov himself. One of his last scientific statements is (translated from the original Russian by L.A. Levin):
Contemporary definition
It is discussed in Cover and Thomas. It is extensively studied in Vereshchagin and Vitányi where also the main properties are resolved.
The |
https://en.wikipedia.org/wiki/Shunamitism | Shunamitism (also referred to as gerocomy) is the practice of an old man sleeping with, but not necessarily having sex with, a young virgin to preserve his youth. It is considered an esoteric youth-enhancing method. The rationale was that the heat and moisture of the young woman would transfer to the old man and revitalize him.
The term is based on the biblical story of King David and Abishag. The young woman, who was from Shunem, was also referred to as a Shunammite. When King David was old and could not stay warm, his servants found Abishag to sleep with him, though he had no intimate relations with her: therefore, she was still a virgin.
Among scientific physicians, Thomas Sydenham (17th century) prescribed shunamitism for his patients. The Dutch Herman Boerhaave (18th century) also recommended this method to an old Burgomaster, citing it can restore strength and spirits.
Similar East Asian traditions
The practice is known by the name Shaoyintongqin (少陰同寢).
China
In the 16th century Chinese medical book Bencao Gangmu by Li Shizhen, it records that "For old man, or humans who lack the energy, sleep with a girl who is before 14, as there is no better medicine than receiving the qi that is present in a young girl", however it advises not to do any sexual acts and just sleep when performing the practice, as it would have a reverse effect if you do. The book also notes the relatively new variant during the time called "contact for supplementation", which lets the girl send the qi to enter the nose orifices, navel, and essence(sperm) gate, so as to reach their cinnabar fields. It also advises to perform it during the nighttime instead of daytime.
Su Nü Jing states how sleeping with a virgin would make diseases disappear.
Korea
The young girl that was used for the practice was called "witbangagi" (윗방아기) and was usually of slave origin or from a poor economic background and was usually used by the Yangban class. The practice continued until the early 20th century. |
https://en.wikipedia.org/wiki/Project%20Cyclops | Project Cyclops is a 1971 NASA project that investigated how SETI should be conducted. As a NASA product the report is in the public domain. The project team created a design for coordinating large numbers of radio telescopes to search for Earth-like radio signals at a distance of up to 1,000 light-years to find intelligent life. The proposed design involving between 1,000 and 2,500 steerable dishes of 100m diameter each was shelved due to costs. However, the report became the basis for much of the SETI work to follow.
Original conclusions
The main conclusions, taken verbatim from the report. The italics are in the original, as is the flowery language (see for example conclusion 12):
1. It is vastly less expensive to look for and to send signals than to attempt contact by spaceship or by probes. This conclusion is based not on the present state of our technological prowess but on our present knowledge of physical law.
2. The order-of-magnitude uncertainty in the average distance between communicative civilizations in the galaxy strongly argues for an expandable search system. The search can be begun with the minimum system that would be effective for nearby stars. The system is then expanded and the search carried farther into space until success is achieved or a new search strategy is initiated.
3. Of all the communication means at our disposal, microwaves are the best. They are also the best for other races and for the same reasons. The energy required at these wavelengths is least and the necessary stabilities and collecting areas are fundamentally easier to realize and cheaper than at shorter wavelengths.
4. The best part of the microwave region is the low frequency end of the "microwave window"- frequencies from about 1 to 2 or 3 GHz. Again, this is because greater absolute frequency stability is possible there, the Doppler rates are lower, beamwidths are broader for a given gain, and collecting area is cheaper than at the high end of the window.
5. Na |
https://en.wikipedia.org/wiki/List%20of%20East%20Timorese%20flags |
National flag
Military flags
Historical flags
Political flags
Municipal flags
See also
Flag of East Timor
Coat of arms of East Timor |
https://en.wikipedia.org/wiki/Hadamard%20test | In quantum computation, the Hadamard test is a method used to create a random variable whose expected value is the expected real part , where is a quantum state and is a unitary gate acting on the space of . The Hadamard test produces a random variable whose image is in and whose expected value is exactly . It is possible to modify the circuit to produce a random variable whose expected value is .
Description of the circuit
To perform the Hadamard test we first calculate the state . We then apply the unitary operator on conditioned on the first qubit to obtain the state . We then apply the Hadamard gate to the first qubit, yielding .
Measuring the first qubit, the result is with probability , in which case we output . The result is with probability , in which case we output . The expected value of the output will then be the difference between the two probabilities, which is
To obtain a random variable whose expectation is follow exactly the same procedure but start with .
The Hadamard test has many applications in quantum algorithms such as the Aharonov-Jones-Landau algorithm.
Via a very simple modification it can be used to compute inner product between two states and : instead of starting from a state it suffice to start from the ground state , and perform two controlled operations on the ancilla qubit. Controlled on the ancilla register being , we apply the unitary that produces in the second register, and controlled on the ancilla register being in the state , we create in the second register. The expected value of the measurements of the ancilla qubits leads to an estimate of . The number of samples needed to estimate the expected value with absolute error is , because of a Chernoff bound. This value can be improved to using amplitude estimation techniques. |
https://en.wikipedia.org/wiki/Gauss%E2%80%93Kuzmin%E2%80%93Wirsing%20operator | In mathematics, the Gauss–Kuzmin–Wirsing operator is the transfer operator of the Gauss map that takes a positive number to the fractional part of its reciprocal. (This is not the same as the Gauss map in differential geometry.) It is named after Carl Gauss, Rodion Kuzmin, and Eduard Wirsing. It occurs in the study of continued fractions; it is also related to the Riemann zeta function.
Relationship to the maps and continued fractions
The Gauss map
The Gauss function (map) h is :
where denotes the floor function.
It has an infinite number of jump discontinuities at x = 1/n, for positive integers n. It is hard to approximate it by a single smooth polynomial.
Operator on the maps
The Gauss–Kuzmin–Wirsing operator acts on functions as
Eigenvalues of the operator
The first eigenfunction of this operator is
which corresponds to an eigenvalue of λ1 = 1. This eigenfunction gives the probability of the occurrence of a given integer in a continued fraction expansion, and is known as the Gauss–Kuzmin distribution. This follows in part because the Gauss map acts as a truncating shift operator for the continued fractions: if
is the continued fraction representation of a number 0 < x < 1, then
Because is conjugate to a Bernoulli shift, the eigenvalue is simple, and since the operator leaves invariant the Gauss–Kuzmin measure, the operator is ergodic with respect to the measure. This fact allows a short proof of the existence of Khinchin's constant.
Additional eigenvalues can be computed numerically; the next eigenvalue is λ2 = −0.3036630029...
and its absolute value is known as the Gauss–Kuzmin–Wirsing constant. Analytic forms for additional eigenfunctions are not known. It is not known if the eigenvalues are irrational.
Let us arrange the eigenvalues of the Gauss–Kuzmin–Wirsing operator according to an absolute value:
It was conjectured in 1995 by Philippe Flajolet and Brigitte Vallée that
In 2018, Giedrius Alkauskas gave a convincing argument th |
https://en.wikipedia.org/wiki/Password%20psychology | Living in the intersection of cryptography and psychology, password psychology is the study of what makes passwords or cryptographic keys easy to remember or guess.
In order for a password to work successfully and provide security to its user, it must be kept secret and un-guessable; this also requires the user to memorize their password. The psychology behind choosing a password is a unique balance between memorization, security and convenience. Password security involves many psychological and social issues including; whether or not to share a password, the feeling of security, and the eventual choice of whether or not to change a password. Passwords may also be reflective of personality. Those who are more uptight or security-oriented may choose longer or more complicated passwords. Those who are lax or who feel more secure in their everyday lives may never change their password. The most common password is Password1, which may point to convenience over security as the main concern for internet users.
History
The use and memorization of both nonsense and meaningful alphanumeric material has had a long history in psychology beginning with Hermann Ebbinghaus. Since then, numerous studies have established that not only are both meaningful and nonsense “words” easily forgotten, but that both their forgetting curves are exponential with time. Chomsky advocates meaning as arising from semantic features, leading to the idea of “concept formation” in the 1930s.
Current research
Research is being done to find new ways of enhancing and creating new techniques for cognitive ability and memorization when it comes to password selection. A study from 2004 indicates that the typical college student creates about 4 different passwords for use with about 8 different items, such as computers, cell phones, and email accounts, and the typical password is used for about two items. Information about the type of passwords points to an approximate even split between linguistic and nu |
https://en.wikipedia.org/wiki/Common%20misunderstandings%20of%20genetics | During the latter half of the 20th century, the fields of genetics and molecular biology matured greatly, significantly increasing understanding of biological heredity. As with other complex and evolving fields of knowledge, the public awareness of these advances has primarily been through the mass media, and a number of common misunderstandings of genetics have arisen.
Genetic determinism
It is a popular misconception that all patterns of an animal's behaviour, and more generally its phenotype, are rigidly determined by its genes. Although many examples of animals exist that display certain well-defined behaviour that is genetically programmed, these examples cannot be extrapolated to all animal behaviour. There is good evidence that some basic aspects of human behaviour, such as circadian rhythms are genetically based, but it is clear that many other aspects are not.
In the first place, much phenotypic variability does not stem from genes themselves. For example:
Epigenetic inheritance. In the widest definition this includes all biological inheritance mechanisms that do not change the DNA sequence of the genome. In a narrower definition it excludes biological phenomena such as the effects of prions and maternal antibodies which are also inherited and have clear survival implications.
Learning from experience. This feature is obviously important for humans, but there is considerable evidence of learned behaviour in other animal species (vertebrates and invertebrates). There are even reports of learned behaviour in Drosophila larvae.
A gene for X
In the early years of genetics it was suggested that there might be "a gene for" a wide range of particular characteristics. This was partly because the examples studied from Mendel onwards inevitably focused on genes whose effects could be readily identified; partly that it was easier to teach science that way; and partly because the mathematics of evolutionary dynamics is simpler if there is a simple mapping between |
https://en.wikipedia.org/wiki/Radio-86RK | The Radio-86RK () is a build-it-yourself home computer designed in the Soviet Union. It was featured in the popular Radio () magazine for radio hams and electronics hobbyists in 1986. The letters RK in the title stands for the words Radio ham's Computer (). Design of the computer was published in a series of articles describing its logical structure, electrical circuitry, drawings of printed circuit boards and firmware. The computer could be built entirely out of standard off-the-shelf parts. Later it was also available in a kit form as well as fully assembled form.
Predecessors
The Radio-86RK is the successor of earlier build-it-yourself computer of the same designers, the Micro-80, and has limited compatibility with it. Its description was also published in a series of articles in the Radio magazine in the early 1980s. But its complex design, consisting of several modules and containing about 200 chips, lack of printed circuit board drawings and most importantly lack of chips on sale made the assembly of the computer hard to accomplish. Micro-80 computers were assembled by only a few enthusiasts.
Assembly process
To assemble the computer, it was required to acquire the necessary electronic components, to make two printed circuit boards and mount all components on them. It was mostly a single board computer, as the second board served only as the base to mount the keyboard keys. The main board used a single large connector for power, keyboard, tape recorder and even video output. Hence it was easy to disconnect the board and work on both sides of it outside the case.
Next, the firmware has to be written in two erasable ROM chips using a chip programmer. Also a power supply unit, a keyboard and a computer case were to be made. The computer used a normal domestic TV set connected to a composite video input as a display. As most Soviet TVs of the time did not have video inputs, it was necessary to install a special module or modify the TV's electronics to impleme |
https://en.wikipedia.org/wiki/Netsniff-ng | netsniff-ng is a free Linux network analyzer and networking toolkit originally written by Daniel Borkmann. Its gain of performance is reached by zero-copy mechanisms for network packets (RX_RING, TX_RING), so that the Linux kernel does not need to copy packets from kernel space to user space via system calls such as recvmsg(). libpcap, starting with release 1.0.0, also supports the zero-copy mechanism on Linux for capturing (RX_RING), so programs using libpcap also use that mechanism on Linux.
Overview
netsniff-ng was initially created as a network sniffer with support of the Linux kernel packet-mmap interface for network packets, but later on, more tools have been added to make it a useful toolkit such as the iproute2 suite, for instance. Through the kernel's zero-copy interface, efficient packet processing can be reached even on commodity hardware. For instance, Gigabit Ethernet wire-speed has been reached with netsniff-ng's trafgen. The netsniff-ng toolkit does not depend on the libpcap library. Moreover, no special operating system patches are needed to run the toolkit. netsniff-ng is free software and has been released under the terms of the GNU General Public License version 2.
The toolkit currently consists of a network analyzer, packet capturer and replayer, a wire-rate traffic generator, an encrypted multiuser IP tunnel, a Berkeley Packet Filter compiler, networking statistic tools, an autonomous system trace route and more:
netsniff-ng, a zero-copy analyzer, packet capturer and replayer, itself supporting the pcap file format
trafgen, a zero-copy wire-rate traffic generator
mausezahn, a packet generator and analyzer for HW/SW appliances with a Cisco-CLI
bpfc, a Berkeley Packet Filter compiler
ifpps, a top-like kernel networking statistics tool
flowtop, a top-like netfilter connection tracking tool with Geo-IP information
curvetun, a lightweight multiuser IP tunnel based on elliptic-curve cryptography
astraceroute, an autonomous system trace rou |
https://en.wikipedia.org/wiki/Vadym%20Slyusar | Vadym Slyusar (born 15 October 1964, vil. Kolotii, Reshetylivka Raion, Poltava region, Ukraine) – Soviet and Ukrainian scientist, Professor, Doctor of Technical Sciences, Honored Scientist and Technician of Ukraine, founder of tensor-matrix theory of digital antenna arrays (DAAs), N-OFDM and other theories in fields of radar systems, smart antennas for wireless communications and digital beamforming.
Scientific results
N-OFDM theory
In 1992 Vadym Slyusar patented the 1st optimal demodulation method for N-OFDM signals after Fast Fourier transform (FFT).
From this patent was started the history of N-OFDM signals theory. In this regard, W. Kozek and A. F. Molisch wrote in 1998 about N-OFDM signals with the sub-carrier spacing , that "it is not possible to recover the information from the received signal, even in the case of an ideal channel." But in 2001 Vadym Slyusar proposed such Non-orthogonal frequency digital modulation (N-OFDM) as an alternative of OFDM for communications systems.
The next publication of V. Slysuar about this method has priority in July 2002 before the conference paper of I. Darwazeh and M.R.D. Rodrigues (September, 2003) regarding SEFDM.
The description of the method of optimal processing for N-OFDM signals without FFT of ADC samples was transferred to publication by V. Slyusar in October 2003.
The theory N-OFDM of V. Slyusar inspired numerous investigations in this area of other scientists.
Tensor-matrix theory of digital antenna array
In 1996 V. Slyusar proposed the column-wise Khatri–Rao product to estimate four coordinates of signals sources at a digital antenna array. The alternative concept of the matrix product, which uses row-wise splitting of matrices with a given quantity of rows (Face-splitting product), was proposed by V. Slyusar in 1996 as well.
After these results the tensor-matrix theory of digital antenna arrays and new matrix operations was evolved (such as the Block Face-splitting product, Generalized Face-splitting pr |
https://en.wikipedia.org/wiki/Comet%20Encke | Comet Encke , or Encke's Comet (official designation: 2P/Encke), is a periodic comet that completes an orbit of the Sun once every 3.3 years. (This is the shortest period of a reasonably bright comet; the faint main-belt comet 311P/PanSTARRS has a period of 3.2 years.) Encke was first recorded by Pierre Méchain on 17 January 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke. Like Halley's Comet, it is unusual in its being named after the calculator of its orbit rather than its discoverer. Like most comets, it has a very low albedo, reflecting only 4.6% of the light its nucleus receives, although comets generate a large coma and tail that can make them much more visible during their perihelion (closest approach to the Sun). The diameter of the nucleus of Encke's Comet is 4.8 km.
Discovery
As its official designation implies, Encke's Comet was the first periodic comet discovered after Halley's Comet (designated 1P/Halley). It was independently observed by several astronomers, the first two being Pierre Méchain and Charles Messier in 1786. It was next observed by Caroline Herschel in 1795 and was "discovered" for a third time by Jean-Louis Pons in 1818. Its orbit was calculated by Johann Franz Encke, who through laborious calculations was able to link observations of comets in 1786 (designated 2P/1786 B1), 1795 (2P/1795 V1), 1805 (2P/1805 U1) and 1818 (2P/1818 W1) to the same object. In 1819 he published his conclusions in the journal Correspondance astronomique, and predicted correctly its return in 1822 (2P/1822 L1). It was recovered by Carl Ludwig Christian Rümker at Parramatta Observatory on 2 June 1822.
Orbit
Comets are in unstable orbits that evolve over time due to perturbations and outgassing. Given Encke's low orbital inclination near the ecliptic and brief orbital period of 3 years, the orbit of Encke is frequently perturbed by the inner planets. Encke is currently close to a 7:2 mean motion r |
https://en.wikipedia.org/wiki/Hyperon | In particle physics, a hyperon is any baryon containing one or more strange quarks, but no charm, bottom, or top quark. This form of matter may exist in a stable form within the core of some neutron stars. Hyperons are sometimes generically represented by the symbol Y.
History and research
The first research into hyperons happened in the 1950s and spurred physicists on to the creation of an organized classification of particles.
The term was coined by French physicist Louis Leprince-Ringuet in 1953, and announced for the first time at the cosmic ray conference at Bagnères de Bigorre in July of that year, agreed upon by Leprince-Ringuet, Bruno Rossi, C.F. Powell, William B. Fretter and Bernard Peters.
Today, research in this area is carried out on data taken at many facilities around the world, including CERN, Fermilab, SLAC, JLAB, Brookhaven National Laboratory, KEK, GSI and others. Physics topics include searches for CP violation, measurements of spin, studies of excited states (commonly referred to as spectroscopy), and hunts for exotic forms such as pentaquarks and dibaryons.
Properties and behavior
Being baryons, all hyperons are fermions. That is, they have half-integer spin and obey Fermi–Dirac statistics. Hyperons all interact via the strong nuclear force, making them types of hadron. They are composed of three light quarks, at least one of which is a strange quark, which makes them strange baryons.
Excited hyperon resonances and ground-state hyperons with a '*' included in their notation decay via the strong interaction. For Ω⁻ as well as the lighter hyperons this decay mode is not possible given the particle masses and the conservation of flavor and isospin necessary in strong interactions. Instead, these decay weakly with non-conserved parity. An exception to this is the Σ⁰ which decays electromagnetically into Λ on account of carrying the same flavor quantum numbers. The type of interaction through which these decays occur determine the average li |
https://en.wikipedia.org/wiki/Neolentinus%20ponderosus | Neolentinus ponderosus, commonly known as the giant sawgill, or ponderous lentinus, is a species of fungus in the family Gloeophyllaceae. Found in western North America, it was originally described in 1965 as a species of Lentinus by American mycologist Orson K. Miller.
Taxonomy
The fungus was first described as Lentinellus montanus by Orson K. Miller, based on collections that he had made in Idaho. In 1985 it was transferred to Neolentinus, a segregate genus created for Lentinus-type fungi that cause a brown rot in wood. The specific epithet ponderosa derives from the Latin word for "heavy".
Description
The fruit bodies have convex to flattened caps ranging from in diameter. The caps have small cinnamon-brown scales (squamules) on the surface and a margin that is usually curved inward initially. The narrow gills have an adnate attachment to the stipe and are closely spaced, with intervening lamellulae (short gills) that extend about two-thirds of the distance to the stipe. The gill edges are serrated (notched like a saw), a feature that inspired the mushroom's common name. Gills are initially whitish before aging to light buff to light orange. The stipe measures long by thick. Its reddish-brown surface is made of small scales that are less dense in the upper half, where it has a more whitish or buff color.
Fruit bodies produce a dull white to buff spore print. Microscopically, the spores are somewhat spindle-shaped when viewed from the side, and elliptical viewed from the front; they measure 8–10.5 by 3.5–4.4 μm and are inamyloid. The basidia (spore-bearing cells) are thin-walled and club-shaped, four-spored, and measure 26–36 by 5–8.8 μm. The cystidia on both the faces and edges of the gills are thin-walled, hyaline (translucent), narrowly club-shaped, and measure 26–36 by 5–8.8 μm. The cap cuticle comprises threadlike hyphae with a diameter of 4.4–8 μm, while the cap flesh is made of interwoven hyphae (both thick- and thin-walled) measuring 2.5–6 μm. Clamp |
https://en.wikipedia.org/wiki/96th%20meridian%20east | The meridian 96° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.
The 96th meridian east forms a great circle with the 84th meridian west.
From Pole to Pole
Starting at the North Pole and heading south to the South Pole, the 85th meridian east passes through:
{| class="wikitable plainrowheaders"
! scope="col" width="120" | Co-ordinates
! scope="col" | Country, territory or sea
! scope="col" | Notes
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Arctic Ocean
| style="background:#b0e0e6;" |
|-valign="top"
|
! scope="row" | Russia
| Krasnoyarsk Krai — Komsomolets Island and October Revolution Island, Severnaya Zemlya
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Kara Sea
| style="background:#b0e0e6;" |
|-valign="top"
|
! scope="row" | Russia
| Krasnoyarsk Krai — The Nordenskiöld Archipelago and the mainland Irkutsk Oblast — from Krasnoyarsk Krai — from Tuva Republic — from
|-
|
! scope="row" | Mongolia
|
|-valign="top"
|
! scope="row" | China
| Xinjiang Gansu — from Qinghai — from Tibet — from
|-valign="top"
|
! scope="row" | India
| Arunachal Pradesh — partly claimed by China
|-
|
! scope="row" | Myanmar (Burma)
|
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Indian Ocean
| style="background:#b0e0e6;" | Andaman Sea
|-
|
! scope="row" | Indonesia
| Island of Sumatra
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Indian Ocean
| style="background:#b0e0e6;" |
|-
|
! scope="row" | Indonesia
| Island of Simeulue
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Indian Ocean
| style="background:#b0e0e6;" |
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Southern Ocean
| style="background:#b0e0e6;" |
|-
|
! scope="row" | Antarctica
| Austral |
https://en.wikipedia.org/wiki/Dancing%20mania | Dancing mania (also known as dancing plague, choreomania, St. John's Dance, tarantism and St. Vitus' Dance) was a social phenomenon that occurred primarily in mainland Europe between the 14th and 17th centuries. It involved groups of people dancing erratically, sometimes thousands at a time. The mania affected adults and children who danced until they collapsed from exhaustion and injuries. One of the first major outbreaks was in Aachen, in the Holy Roman Empire (in modern-day Germany), in 1374, and it quickly spread throughout Europe; one particularly notable outbreak occurred in Strasbourg in 1518 in Alsace, also in the Holy Roman Empire (now in modern-day France).
Affecting thousands of people across several centuries, dancing mania was not an isolated event, and was well documented in contemporary reports. It was nevertheless poorly understood, and remedies were based on guesswork. Often musicians accompanied dancers, due to a belief that music would treat the mania, but this tactic sometimes backfired by encouraging more to join in. There is no consensus among modern-day scholars as to the cause of dancing mania.
The several theories proposed range from religious cults being behind the processions to people dancing to relieve themselves of stress and put the poverty of the period out of their minds. It is speculated to have been a mass psychogenic illness, in which physical symptoms with no known physical cause are observed to affect a group of people, as a form of social influence.
Definition
"Dancing mania" is derived from the term "choreomania", from the Greek choros (dance) and mania (madness), and is also known as "dancing plague". The term was coined by Paracelsus, and the condition was initially considered a curse sent by a saint, usually St. John the Baptist or St. Vitus, and was therefore known as "St. Vitus' Dance" or "St. John's Dance". Victims of dancing mania often ended their processions at places dedicated to that saint, who was prayed to in a |
https://en.wikipedia.org/wiki/Quantum%20healing | Quantum healing is a pseudoscientific mixture of ideas which purportedly draws from quantum mechanics, psychology, philosophy, and neurophysiology. Advocates of quantum healing assert that quantum phenomena govern health and wellbeing. There are different versions, which allude to various quantum ideas including wave particle duality and virtual particles, and more generally to "energy" and to vibrations. Quantum healing is a form of alternative medicine.
Deepak Chopra coined the term "quantum healing" when he published the first edition of his book with that title in 1989. His discussions of quantum healing have been characterised as technobabble - "incoherent babbling strewn with scientific terms" which drives those who actually understand physics "crazy" and as "redefining Wrong".
Quantum healing has a number of vocal followers, but the scientific community widely regards it as nonsensical. The main criticism revolves around its systematic misinterpretation of modern physics, especially of the fact that macroscopic objects (such as the human body or individual cells) are much too large to exhibit inherently quantum properties like interference and wave function collapse.
Physicist and science communicator Brian Cox argues that misuse of the word "quantum", such as its use in the phrase quantum healing, has a negative effect on society as it undermines genuine science and discourages people from engaging with conventional medicine. He states that "for some scientists, the unfortunate distortion and misappropriation of scientific ideas that often accompanies their integration into popular culture is an unacceptable price to pay."
See also
List of esoteric healing articles
Quantum mysticism
Quantum mind |
https://en.wikipedia.org/wiki/Journal%20of%20Spatial%20Science | The Journal of Spatial Science is an academic journal about spatial sciences published by Taylor & Francis on behalf of the Mapping Sciences Institute (Australia) and the Surveying and Spatial Sciences Institute.
It covers cartography, geodesy, geographic information science, hydrography, digital image analysis and photogrammetry, remote sensing, surveying and related areas.
Its editor-in-chief is Graeme Wright;
its 2018 impact factor is 1.711.
It started in 2004 as a continuation of both Cartography (1954-2003) and Australian Surveyor (1928-2003).
It also absorbed Geomatics Research Australasia (1995-2004), a continuation of the Australian Journal of Geodesy, Photogrammetry, and Surveying (1979-1994). |
https://en.wikipedia.org/wiki/Denisyuk%20polynomials | In mathematics, Denisyuk polynomials Den(x) or Mn(x) are generalizations of the Laguerre polynomials introduced by given by the generating function
Notes |
https://en.wikipedia.org/wiki/Quantum%20pendulum | The quantum pendulum is fundamental in understanding hindered internal rotations in chemistry, quantum features of scattering atoms, as well as numerous other quantum phenomena. Though a pendulum not subject to the small-angle approximation has an inherent nonlinearity, the Schrödinger equation for the quantized system can be solved relatively easily.
Schrödinger equation
Using Lagrangian mechanics from classical mechanics, one can develop a Hamiltonian for the system. A simple pendulum has one generalized coordinate (the angular displacement ) and two constraints (the length of the string and the plane of motion). The kinetic and potential energies of the system can be found to be
This results in the Hamiltonian
The time-dependent Schrödinger equation for the system is
One must solve the time-independent Schrödinger equation to find the energy levels and corresponding eigenstates. This is best accomplished by changing the independent variable as follows:
This is simply Mathieu's differential equation
whose solutions are Mathieu functions.
Solutions
Energies
Given , for countably many special values of , called characteristic values, the Mathieu equation admits solutions that are periodic with period . The characteristic values of the Mathieu cosine, sine functions respectively are written , where is a natural number. The periodic special cases of the Mathieu cosine and sine functions are often written respectively, although they are traditionally given a different normalization (namely, that their norm equals ).
The boundary conditions in the quantum pendulum imply that are as follows for a given :
The energies of the system, for even/odd solutions respectively, are quantized based on the characteristic values found by solving the Mathieu equation.
The effective potential depth can be defined as
A deep potential yields the dynamics of a particle in an independent potential. In contrast, in a shallow potential, Bloch waves, as well as quant |
https://en.wikipedia.org/wiki/Modified%20Harvard%20architecture | A modified Harvard architecture is a variation of the Harvard computer architecture that, unlike the pure Harvard architecture, allows memory that contains instructions to be accessed as data. Most modern computers that are documented as Harvard architecture are, in fact, modified Harvard architecture.
Harvard architecture
The original Harvard architecture computer, the Harvard Mark I, employed entirely separate memory systems to store instructions and data. The CPU fetched the next instruction and loaded or stored data simultaneously and independently. This is in contrast to a von Neumann architecture computer, in which both instructions and data are stored in the same memory system and (without the complexity of a CPU cache) must be accessed in turn.
The physical separation of instruction and data memory is sometimes held to be the distinguishing feature of modern Harvard architecture computers. With microcontrollers (entire computer systems integrated onto single chips), the use of different memory technologies for instructions (e.g. flash memory) and data (typically read/write memory) in von Neumann machines is becoming popular. The true distinction of a Harvard machine is that instruction and data memory occupy different address spaces. In other words, a memory address does not uniquely identify a storage location (as it does in a von Neumann machine); it is also necessary to know the memory space (instruction or data) to which the address belongs.
Von Neumann architecture
A computer with a von Neumann architecture has the advantage over Harvard machines as described above in that code can also be accessed and treated the same as data, and vice versa. This allows, for example, data to be read from disk storage into memory and then executed as code, or self-optimizing software systems using technologies such as just-in-time compilation to write machine code into their own memory and then later execute it. Another example is self-modifying code, which all |
https://en.wikipedia.org/wiki/Teen%20Age%20Message | The Teen Age Message (TAM) was a series of interstellar radio transmissions sent from the Yevpatoria Planetary Radar to six solar-type stars during August–September 2001. The structure of the TAM was suggested by Alexander Zaitsev, Chief Scientist at Russia's Institute of Radio-engineering and Electronics. The message's content and target stars were selected by a group of teens from four Russian cities, who collaborated in person and via the Internet. Each transmission comprised three sections: a sounding, a live theremin concert, and digital data including images and text. TAM was humanity's fourth Active SETI broadcast and the first musical interstellar radio message.
Overview
Zaitsev's proposal for a musical message – the "First Theremin Concert for Extraterrestrials" – was submitted to the Arecibo Observatory in July 2000. It was rejected amid concerns over the dangers posed by advertising the presence of humanity to unknown and possibly highly advanced civilizations. After another unsuccessful attempt to garner support, the project was backed by the Yevpatoria RT-70 radio telescope with funding from the Education Department of Moscow. Unlike the previous digital-only messages Arecibo-1974 and Cosmic Call 1, TAM had a three-part structure, each containing different forms of information. Such structure was suggested by Alexander Zaitsev, and was intended to make the message easier to detect and interpret. The three elements of each transmission were:
A coherent sounding signal with slow Doppler wavelength tuning to imitate transmission from the Sun's center. This signal was transmitted in order to help extraterrestrials detect the TAM and diagnose the radio propagation effect of the interstellar medium.
Analog sound output from a theremin. This electric musical instrument produces a quasi-sinusoidal signal which is easily extracted from background noise. There were seven musical compositions in the "First Theremin Concert for Extraterrestrials".
Binary digit |
https://en.wikipedia.org/wiki/Cahiers%20de%20Topologie%20et%20G%C3%A9om%C3%A9trie%20Diff%C3%A9rentielle%20Cat%C3%A9goriques | The Cahiers de Topologie et Géométrie Différentielle Catégoriques (French: Notebooks of categorical topology and categorical differential geometry) is a French mathematical scientific journal established by Charles Ehresmann in 1957. It concentrates on category theory "and its applications, [e]specially in topology and differential geometry". Its older papers (two years or more after publication) are freely available on the internet through the French NUMDAM service.
It was originally published by the Institut Henri Poincaré under the name Cahiers de Topologie; after the first volume, Ehresmann changed the publisher to the Institut Henri Poincaré and later Dunod/Bordas. In the eighth volume he changed the name to Cahiers de Topologie et Géométrie Différentielle. After Ehresmann's death in 1979 the editorship passed to his wife Andrée Ehresmann; in 1984, at the suggestion of René Guitart, the name was changed again, to add "Catégoriques". |
https://en.wikipedia.org/wiki/Lactarius%20resimus | Lactarius resimus is a species of mushrooms in the genus Lactarius, which is considered a delicacy in Russia and some other countries of Eastern Europe when pickled in salt. There it is considered one of three tastiest edible mushrooms, along with Boletus edulis and Lactarius deliciosus, though it is not held in high esteem elsewhere. The mushroom forms a mycorrhizal relationship with birch and with conifers too (pine).
The cap ranges from 4 to 15 cm in diameter. The stalk ranges from 2 to 6 cm in length and 1 to 3 cm in width. The mushroom is generally white, but stains yellow to orange. The spores are white-yellow, elliptical and bumpy.
Similar species include Lactarius pubescens var. betulae and Lactarius torminosus.
See also
List of Lactarius species |
https://en.wikipedia.org/wiki/Leptocylindrus | Leptocylindrus is a genus of diatoms belonging to the family Leptocylindraceae. They are long, cylindrical diatoms that are made up of multiple cells in a line (described as a chain). These cells have chloroplast to allow it to produce energy through photosynthesis by taking in sunlight and carbon dioxide to create sugars. the cells are attached at the cell walls called valves, the cell wall is slightly concave on one side and convex on the other so that the other cell wall attached will fit together.
Reproduction
Leptocylindrus reproduction is both asexual and (in some species) sexual. For the specific species Leptocylindrus danicus, it goes through sexual reproduction when its cells are between 3 and 8 micrometers in width (cells above this width go through asexual reproduction). It begins with Leptoclindrus cells splitting into two uneven gametangia. The female gametangia are longer and more brightly colored cell than the male gametangia. Then the process of meiosis occurs, where gametes are produced in the gametangia, the male gametangium (also known as the spermatogonangium) burst to release quadriflagellate spermia, which divide into biflagellate sperma and again into unflagellate sperm (or just sperm), this process takes about twelve hours to complete. After meiosis the female gametangium (or egg) bends at an angle so that the sperm can attach and enter the egg. the site of entry by the sperm starts to swell as the cytoplasm is sent to the area. after fertilization the auxospore forms at this site, the cytoplasm then contracts and valves (distinct halves of the cell wall) form to create the resting spore. these resting spores finally separate from the parent cell and can remain dormant for long periods because of their thick walls. The whole process in total takes about 36 hours to complete. The resting spores under good conditions well then germinate and then well shed there old valves to form a chain with a maximum width of 14 micrometers, and will reprodu |
https://en.wikipedia.org/wiki/Photopea | Photopea ( ) is a web-based photo and graphics editor. It is used for image editing, making illustrations, web design or converting between different image formats. Photopea is advertising-supported software. It is compatible with all modern web browsers, including Opera, Edge, Chrome, and Firefox. The app is compatible with raster and vector graphics, such as Photoshop's PSD as well as JPEG, PNG, DNG, GIF, SVG, PDF and other image file formats. While browser-based, Photopea stores all files locally, and does not upload any data to a server.
Features
Photopea has various image editing tools including spot healing, a clone stamp healing brush, and a patch tool. The software supports layers, layer masks, channels, selections, paths, smart objects, layer styles, text layers, filters and vector shapes.
Reception
Photopea has received positive coverage due to its similarities to Adobe Photoshop in design and workflow, making it an easier program for those trained in Photoshop to use, compared to other free raster image editors such as GIMP.
See also
Comparison of raster graphics editors
Pixelmator
Adobe Photoshop
SumoPaint
Procreate
GIMP |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.