About contraction in the grammar of modern languages, which involves elision contraction in Ancient Greek ... grammar , contraction can denote the formation of a new word from one word or a group of words, for example ... parlance. ref name harts Contraction is also distinguished from clipping morphology clipping , where beginnings and endings are omitted. English English grammar An informal type of contraction occurs ... , Common English contractions. DEFAULTSORT ContractionGrammar Category Abbreviations Category ... vowels together Synaeresis A contraction is a shortened version of the written and spoken forms ... contraction of two words that does not fall into either of the above categories is let s , a contraction ... other languages. It is almost always acceptable to write out or say all of the words of a contraction ... form its has no apostrophe, while the contraction of it is or it has does have an apostrophe it s . The same is true of the possessive form of you your with its contraction you re for you are . See .... class wikitable Full Form ref name pulleyblank cite book title Outline of Classical Chinese Grammar ... search containing William H. Baxter s reconstructions. ref Contraction ref name pulleyblank ... can also be contraction for . can be used on its own with the meaning of all, the class ... for le , aux for les , du for de le , and des for de les . However, the contraction of cela demonstrative ... and the article grammar article for example, von dem becomes vom , zu dem becomes zum , or an das ... the influence of French language French , built contraction patterns involving long phrases and entire ... unwilling do not want which was formed by a contraction of ne volo volo meaning I want . Similarly ... Form Transliteration Contraction Transliteration lang ja etc. te iru te ita te imasu ... s tivaldu , with the two words forming a contraction and the p lenition leniting into a v or w . Or date ... misconceptions Poetic contraction Portmanteau word Relaxed pronunciation Synalepha Syncope phonetics ... more details
wiktionary Contraction may refer to In physiology Muscle contraction , one that occurs when a muscle fiber lengthens or shortens Uterine contraction , contraction of the uterus , such as during childbirth Wound healing ContractionContraction , a stage in wound healing In linguistics Synalepha , merging of two syllables of adjacent words Elision , the loss of a sound Syncope phonetics , the loss of sounds inside a word Contractiongrammar , the shortening of a word or words by loss of a sound or sounds Synaeresis , the pronunciation of two vowels as a diphthong Crasis , contraction of two vowels into one monophthong In science Lanthanoid contraction , the decrease in size of the ionic radius of lanthanide elements with their growing atomic number series of Rare Earth Elements REE in the Mendeleev Table The reverse of thermal expansion In mathematics Contraction mapping , in mathematics, a type of function on a metric space Contraction operator theory Edge contraction or vertex contraction, graph operations used in graph theory Tensor contraction in tensor theory Conditional independence Rules of conditional independence Contraction Conditional Independence , in probability, one of the rules of Conditional Independence Other Economic contraction or recession , a reversal of economic growth the opposite of economic expansion A structural rule in proof theory see idempotency of entailment In sports, the sometimes forced elimination of a team. The opposite of Expansion team expansion . Example the elimination of several teams after the Canadian Football League Canadian Football League s CFL USA failed attempt to expand into the United States in the early 1990s. disambig cs Kontrakce de Kontraktion es Contracci n fr Contraction nl Contractie pl Kontrakcja sv Kontraktion ... more details
Unreferenced stub auto yes date December 2009 Orphan date November 2006 A poetic contraction is a contractiongrammarcontraction used primarily in poetry . An example is o er . These are different from contractions such as can t , in that they are primarily used for a certain sound and are uncommon in modern speech and writing. DEFAULTSORT Poetic Contraction Category Writing Poetry stub ... more details
In mathematics , contraction principle may refer to the Banach fixed point theorem , also known as the contraction mapping theorem principle the Contraction principle large deviations theory contraction principle in large deviations theory mathdab ... more details
Unreferenced stub auto yes date December 2009 Orphan date November 2006 Nebular contraction is the fragmentation and densitation of matter and gasses in a nebular cloud related to the creation of Solar objects theorized as the Solar Nebular theory . DEFAULTSORT Nebular Contraction Category Nebulae Astronomy stub Nebula stub ... more details
Image Wiggers Diagram.png thumb 350px Wiggers diagram of the cardiac cycle , with isovolumetric contraction marked at upper left. Isovolumetric contraction is a term used in cardiac physiology to refer to an event occurring in early systole medicine systole , during which the ventricles contract with no corresponding volume change. Description In a healthy young adult, blood from the venous return enters the atrium heart atria and flows to the ventricle heart ventricle s via the opened tricuspid and mitral valves. Atrial contraction rapidly follows, actively pumping about 20 of the returning blood. As diastole ends, the ventricles start depolarizing and, while ventricular pressure starts to rise due to contraction, the atrioventricular valves close, so as to prevent back flow to the atria. At this stage, which corresponds to the R peak or the QRS complex seen on an ECG , the aortic and pulmonary valves are also closed . The net result of this situation is that, while contraction causes ventricular pressure to rise sharply, there is no overall change in volume because of the closed valves. The isovolumetric contraction lasts for about 0.03 s, but this short period of time is enough to build up a sufficiently high pressure that will eventually overcome that of the aorta and the pulmonary trunk upon opening of the semilunar valves, therefore allowing the correct unidirectional flow of blood. Etymology The word contains the suffix iso , derived from the Ancient Greek sos , meaning equal . Therefore, an isovolumetric contraction is one in which the volume of fluid remains constant. See also Heart Cardiac cycle Blood pressure Wiggers diagram References Pocock, J., and Richards ... Contraction on cvphysiology.com http medical dictionary.thefreedictionary.com isovolumic contraction Isovolumetric Contraction on medical dictionary.com Cardiovascular physiology DEFAULTSORT Isovolumetric Contraction Category Blood pressure Category Cardiovascular physiology bs Dijastola cs Diastola ... more details
Unreferenced date December 2009 Myogenic contraction refers to a Muscle contractioncontraction initiated by the myocyte cell itself instead of an outside occurrence or stimulus such as nerve innervation. Mechanisms Unstable Membrane Potentials Many cell biology cells have resting membrane potential s that are unstable. This instability is usually due to ion channels in the cell membrane that spontaneously open and close e.g. Funny current I sub f sub channels in cardiac pacemaker cells . When the membrane potential reaches Action potential Threshold and initiation depolarization threshold an action potential AP is fired, excitation contraction coupling initiates and the myocyte contracts. Slow wave potentials Slow wave potential are unstable resting membrane potential s that continuously cycle through depolarization and repolarization phases. However, not every cycle reaches Action potential Threshold and initiation depolarization threshold and thus an action potential AP will not always fire. Owing to temporal summation depolarization potentials spaced closely together in time so that they summate , however, cell membrane depolarization will periodically reach Action potential Threshold and initiation depolarization threshold and an action potential will fire, triggering contraction of the myocyte . Pacemaker potentials Pacemaker potential s are unstable resting membrane potential cell membrane potentials that reach Action potential Threshold and initiation depolarization threshold with every depolarization repolarization cycle. This results in action potential AP s being fired according to a set rhythm. Cardiac pacemaker cells, a type of cardiac myocyte in the SA node of heart ... of Ca sup 2 sup ions lead to the initiation of excitation contraction coupling and thus Muscle contractioncontraction of the myocyte. See also Membrane potential br Action potential br Excitation contraction coupling br Myogenic mechanism Myogenic reflex br Category Animal physiology ... more details
Nofootnotes article date June 2011 Vaginal contraction is a muscle contractioncontraction of the pelvic muscles surrounding the vagina , which are most commonly associated with sexual intercourse and orgasm . Although these are generally an involuntary muscular response, some women can control the muscles of the vagina to perform vaginal contractions at will, providing a pleasurable sensation for both parties during sexual intercourse. Involuntary spasm of the muscles around the vagina, usually caused by anxiety, can result in vaginismus . Vaginal contractions should not be confused with uterine contraction s. See also Pelvic floor muscles Muscle tone External links cite journal pmid 8174183 year 1994 last1 Kratochv l first1 S title Vaginal contractions in female orgasm volume 90 issue 1 pages 28 33 journal Ceskoslovenska psychiatrie cite journal doi 10.1097 01.AOG.0000141441.41178.6b title Botulinum Toxin in the Treatment of Refractory Vaginismus year 2004 last1 Ghazizadeh first1 Shirin last2 Nikzad first2 Masoomeh journal Obstetrics & Gynecology volume 104 issue 5, Part 1 pages 922 925 DEFAULTSORT Vaginal Contraction Category Gynaecology sex stub med stub ... more details
Contraction alkalosis refers to the increase in blood pH that occurs as a result of fluid losses volume contraction . The change in pH is especially pronounced with acidic fluid losses caused by problems like vomiting . Pathophysiology Volume contraction ECF volume contraction Extracellular fluid ECF volume contraction is associated with decreased blood volume and decreased renal perfusion pressure. Three compensation mechanisms engage as a result renin secretion is increased, production of angiotensin II is increased, and secretion of aldosterone is increased. Increases in angiotensin II cause increased Na sup sup H sup sup exchange in the proximal tubule and increased HCO sub 3 sub sup sup bicarbonate reabsorption in the proximal tubule due to increased luminal H sup sup . Increased aldosterone secretion stimulates the H ATPase of alpha intercalated cells of the collecting duct, which causes 1 increased distal tubule H sup sup secretion, worsening the metabolic alkalosis, and 2 increased generation of new bicarbonate within these same cells, which will be reabsorbed. Additionally, increased aldosterone secretion causes increased distal tubule K sup sup secretion, in turn causing the hypokalemia seen with contraction alkalosis. Alkalosis also induces H sup sup efflux from cells through the K sup sup H sup sup exchanger, leading to hypokalemia. Treatment Treatment consists of Sodium chloride NaCl infusion to correct ECF volume contraction and administration of K sup sup to replace urinary losses. References http www.nature.com ki journal v54 n6 full 4490448a.html Water electrolyte imbalance and acid base imbalance Category Electrolyte disturbances pt Alcalose de contra o ... more details
to x in G . Vertex identification Vertex identification sometimes called vertex contraction removes the restriction that the contraction must occur over vertices sharing an incident edge. Thus, edge contraction is a special case of vertex identification. The operation may occur on any pair ... contraction Path contraction occurs upon a the set of edges in a Path graph theory path that contract ... Both edge and vertex contraction techniques are valuable in proof by induction on the number .... Edge contraction is used in 3D modelling packages either manually, or through some feature of the modelling ... Mathworld Edge Contraction Category Graph operations ... more details
In applied mathematics, the method of contraction hierarchies is a technique to simplify shortest path routing by first creating precomputed contracted versions of the connection graph . It can be regarded as a special case of highway node routing . ref cite web url http algo2.iti.kit.edu documents routeplanning geisberger dipl.pdf title Contraction Hierarchies Faster and Simpler Hierarchical Routing in Road Networks author Robert Geisberger publisher Institut f r Theoretische Informatik Universit t Karlsruhe date 1 July 2008 accessdate 2010 12 27 ref Contraction hierarchies can be used to generate shortest path routes much more efficiently than Dijkstra s algorithm or previous highway node routing approaches, fact date December 2010 and are used in the OpenTripPlanner software. ref cite web url http opentripplanner.com learn title Learn OpenTripPlanner accessdate 2010 12 27 ref References reflist algorithm stub Category Network theory Category Graph algorithms ... more details
Refimprove date December 2008 The Great Contraction is Milton Friedman s term for the recession which led to the Great Depression . ref name Friedman 1 http www.scribd.com doc 8228118 The Great Contraction by Milton Friedman source 1 , New Preface page ix ref The term served as the title for the relevant chapter in Friedman and Anna J. Schwartz Schwartz s 1963 work A Monetary History of the United States . The chapter was later published as a stand alone paperback entitled The Great Contraction, 1929 33 in 1965. ref cite web title The Great Contraction, 1929 1933 New Edition publisher Princeton University Press url http press.princeton.edu titles 8754.html accessdate 2011 10 28 ref Friedman labelled it thus because he believed that the depression lasted so long due to the Federal Reserve s mismanagement. He argued that the Reserve contracted the monetary supply dramatically, prolonging the Depression, which Friedman claims could have been over by 1931. ref name Friedman 2 http www.thefreemanonline.org featured the great depression according to milton friedman source 2 , Dangers of Centralized Power ref Economists such as Paul Krugman refer to the similarly named and sometimes confused with Great Compression as a period during which economic equality rose due to the progressive tax policies instituted during the years of WWII and the policies of the Roosevelt Administration. References Reflist Category Great Depression econ stub ... more details
A tetanic contraction or tetanized state occurs when a motor unit has been maximally stimulated by its motor neuron . This occurs when a muscle s motor unit is stimulated at a sufficiently high frequency of multiple impulses. Each stimulus causes a twitch. If stimuli are delivered slow enough, the tension in the muscle will relax between successive twitches. If stimuli is delivered at high frequency, then the twitches will add up, resulting in tetanic contraction. When tetanized, the contracting tension in the muscle remains constant in a steady state . This is the maximal contraction. Tetanic contraction may also occur as part of an extrapyramidal adverse drug reaction of some typical antipsychotic drugs, specifically the opisthotonos effect of acute dystonic reaction in which tetanic heightening of entire body, head and belly up occurs. Tetanic contraction may be observed following the use of a device intended to apply transcutaneous electrical muscle stimulation EMS through skin contact electrodes for the purpose of improving abdominal muscle tone. Diseases Tetanic contractions are a symptom of hypoparathyroidism , due to an underdeveloped parathyroid, or injury to the Parathyroid gland parathyroid . ref cite book last Shier first David first2 Jackie last2 Butler first3 Ricki last3 Lewis title Hole s essentials of Human Anatomy & Physiology location Boston publisher McGraw Hill Higher Education page 301 edition Tenth year 2009 isbn 9780072965636 ref See also Muscle contraction Muscle fatigue Tetanus Tetanospasmin References reflist Category Electrophysiology Category Symptoms and signs Nervous and musculoskeletal systems symptom stub it Contrazione tetanica ja ... more details
In multilinear algebra , a tensor contraction is an operation on one or more tensor s that arises from ... to each other in an expression. The contraction of a single mixed tensor occurs when a pair of literal ... tensor with Tensor Tensor rank rank or order reduced by 2. Tensor contraction can be seen as a generalization ... mathematics field k . The core of the contraction operation, and the simplest case, is the natural ... the contraction operation on a tensor of type 1,1 , which is an element of math V otimes V math ... th V sup sup factor, and using the identity on all other factors, defines the k , l contraction ... &minus 1 . ref name fulton harris By analogy with the 1,1 case, the general contraction operation is sometimes called the trace. Contraction in index notation In abstract index notation , the basic contraction of a vector and a dual vector is denoted by math tilde f vec v f gamma v gamma math ... T T i j mathbf e i e j math be a mixed dyadic tensor. Then its contraction is math T i j mathbf e i cdot mathbf e j T i j delta i j T j j T 1 1 cdots T n n math . A general contraction is denoted ... is 2. Metric contraction As in the previous example, contraction on a pair of indices that are either ... to raise or lower one of the indices, as needed, and then one uses the usual operation of contraction. The combined operation is known as metric contraction . ref name o neill Barrett O Neill ... to tensor fields Contraction is often applied to tensor fields over spaces e.g. Euclidean space , manifold s, or scheme mathematics schemes . Since contraction is a purely algebraic operation, it can ... coordinates, its contraction a scalar field U at a point x is given by math U x sum i T i i ... to the theory. For example, the Ricci tensor is a non metric contraction of the Riemann curvature tensor , and the scalar curvature is the unique metric contraction of the Ricci tensor. One can also view contraction of a tensor field in the context of modules over an appropriate ring of functions on the manifold ... more details
Contraction and Convergence C&C is a proposed global framework for reducing greenhouse gas emissions to combat climate change . Conceived by the Global Commons Institute GCI in the early 1990s, the Contraction and Convergence strategy consists of reducing overall emissions of greenhouse gases to a safe level contraction , resulting from every country bringing its emissions per capita to a level which ... to stabilize carbon levels at any level. Advocates of Contraction and Convergence stress ... The contraction part of Contraction and Convergence model calculates the total amount of carbon being put into the atmosphere as a path integral or a total contraction event . Future global emissions ... countries entitlements would continue to fall, subject to the contraction event required to by UNFCCC ... concept of Contraction and Convergence and the specific formulas that the Global Commons Institute ... an acceptable level of risk. However, supporters of Contraction and Convergence believe that a safe ... calculating model Contraction and Convergence C&C was developed over a period of three years in response ... begins with a full term contraction budget for global emissions consistent with stabilising atmospheric ... negotiators at the UNFCCC negotiations internationally share this emissions contraction budget ... contraction rate. This can be on year anywhere between immediate and end of term with or without ... consumers is closed but within the agreed contraction budget. Support C&C has wide support as shown ... contraction and convergence slide 9 ref name COP 9 http www.gci.org.uk UNFCCC C&C Janos Pasztor UNFCCC.pdf ... Global Commons Institute Contraction and Convergence http www.gci.org.uk endorsements.html Global ... GCI EAC.pdf http climatechangeaction.blogspot.com 2007 01 contraction and convergence short video.html Video explaining Contraction and Convergence DEFAULTSORT Contraction And Convergence Category Climate change policy Category Carbon finance de Kontraktion und Konvergenz fr Contraction et convergence ... more details
Merge to Recession discuss Talk Recession Merger proposal date October 2011 Multiple issues wikify December 2010 refimprove January 2009 orphan January 2009 A contraction is a period of economic decline marked by falling real GDP. ref cite book last Sullivan first arthur authorlink Arthur O Sullivan coauthors Steven M. Sheffrin title Economics Principles in action publisher Pearson Prentice Hall year 2003 location Upper Saddle River, New Jersey 07458 pages 548 url http www.pearsonschool.com index.cfm?locator PSZ3R9&PMDbSiteId 2781&PMDbSolutionId 6724&PMDbCategoryId &PMDbProgramId 12881&level 4 doi id isbn 0 13 063085 3 ref See Recession . During the 1870s and 1880s, the recalling of paperbacks, due to pressure by hardmoney Republicans caused a contraction reducing the amount of money per capita by 5 cents. References Reflist DEFAULTSORT Contraction Economics Category Economic problems econ problem stub ... more details
In mathematics , a contraction mapping , or contraction , on a metric space M,d is a function mathematics function f from M to itself, with the property that there is some nonnegative real number math k 1 math such that for all x and y in M , math d f x ,f y leq k ,d x,y . math The smallest such value of k is called the Lipschitz constant of f . Contractive maps are sometimes called Lipschitzian maps . If the above condition is instead satisfied for k &le 1, then the mapping is said to be a non expansive map . More generally, the idea of a contractive mapping can be defined for maps between metric spaces. Thus, if M , d and N , d are two metric spaces, and math f M mapsto N math , then there is a constant k such that math d f x ,f y leq k ,d x,y math for all x and y in M . Every contraction mapping is Lipschitz continuous and hence uniformly continuous for a Lipschitz continuous function, the constant k is no longer necessarily less than 1 . A contraction mapping has at most one fixed point mathematics fixed point . Moreover, the Banach fixed point theorem states that every contraction mapping on a nonempty completeness topology complete metric space has a unique fixed point, and that for any x in M the iterated function sequence x , f x , f f x , f f f x , ... converges to the fixed point. This concept is very useful for iterated function systems where contraction mappings are often used. Banach s fixed point theorem is also applied in proving the existence of solutions of ordinary differential equations, and is used in one proof of the inverse function theorem . ref name shifrin Theodore Shifrin, Multivariable Mathematics , Wiley, 2005, ISBN 0 471 52638 X, pp. 244 260. ref Firmly non expansive mapping A non expansive mapping with math k 1 math can be strengthened ... also Short map Contraction operator theory Note reflist References Vasile I. Istratescu, Fixed ... , Kluwer Academic, London ISBN 0 7923 7073 2 DEFAULTSORT Contraction Mapping Category Metric geometry ... more details
and myosin cross bridge cycling. While under tension, the muscle may Eccentric contraction lengthen , Concentric contraction shorten , or Isometric contraction remain the same . Although the term contraction implies shortening, when referring to the muscular system, it means muscle fibers generating tension with the help of motor neuron s the terms twitch tension , twitch force , and fiber contraction are also used . Voluntary muscle contraction is controlled by the central nervous system. The brain ... type Unreferenced section date August 2009 For voluntary muscles, contraction occurs as a result of conscious ... the intensity of overall muscle contraction. This can be achieved in two ways ref cite journal first ... units are activated, the force of muscle contraction becomes progressively stronger. A concept known as the size principle allows for a gradation of muscle force during weak contraction to occur in small ... synchronously, and, during a contraction, some fraction of the fibers in the muscle will be firing ... organ s and Renshaw cell s . This low level of contraction is a protective mechanism to prevent avulsion fracture avulsion of the tendon&mdash the force generated by a 95 contraction of all fibers ... filament model see also Excitation contraction coupling An action potential originating in the CNS ... filaments and contraction ceases. Classification of voluntary muscular contractions Skeletal muscle contractions can be broadly separated into twitch and tetanic contractions . In a twitch contraction ... contraction can give information about the relative rates of calcium release and re uptake from ... at this level, resulting in a tetanic contraction. If the stimulation is not intense enough, force ... contraction concentric contraction , the force generated is sufficient to overcome the resistance, and the muscle shortens as it contracts. This is what most people think of as a muscle contraction. In Eccentric contraction eccentric contraction , the force generated is insufficient to overcome ... more details
A uterine contraction is a muscle contraction of the uterine smooth muscle . Throughout menstrual cycle The uterus frequently contracts throughout the entire menstrual cycle , and these contractions have been termed endometrial waves or contractile waves . ref name aguilar2010 cite doi 10.1093 humupd dmq016 ref These appear to involve only the sub endometrial layer of the myometrium . ref name aguilar2010 In the early follicular phase , these contractions occur once or twice per minute and last 10 15 seconds with a low amplitude of usually 30 mmHg. ref name aguilar2010 The frequency increases to 3 4 per minute towards ovulation . During the luteal phase , the frequency and amplitude decrease, possibly to facilitate any Implantation human embryo implantation . If implantation does not occur, the frequency remains low, but the amplitude increases dramatically to between 50 and 200 mmHg producing labor like contractions at the time of menstruation . ref name aguilar2010 These contractions are sometimes termed menstrual cramps , ref name medicinenet http www.medicinenet.com menstrual cramps page3.htm medicinenet.com Menstrual Cramps Retrieved January 2011 ref although that term is often used for menstrual pain in general. These contractions may be uncomfortable or even painful, but they are generally significantly less painful than contractions during labour. A hot water bottle or exercising has been found to help. A shift in the myosin expression of the uterine smooth muscle has been hypothesized to avail for changes in the directions of uterine contractions that are seen during the menstrual cycle. ref name aguilar2010 In childbirth In obstetrics , a contraction may refer specifically to the motion of the uterus ref MeshName Uterine Contraction ref as part of the process of childbirth . Contractions, and labour in general, is one condition that releases the hormone oxytocin ... ca Contracci uterina de Wehe fr Contraction ut rine ru uk ... more details
Volume contraction is a decrease in body fluid volume, also including any concomitant loss of osmolyte s. The loss of the water component of body fluid is specifically termed dehydration . ref http www.medterms.com script main art.asp?articlekey 2933 MedicineNet Definition of Dehydration Retrieved on July 2, 2009 ref By body fluid compartment Volume contraction is more or less a loss of extracellular fluid ECF and or intracellular fluid ICF . ECF volume contraction Main Hypovolemia Volume contraction of extracellular fluid is directly coupled to and almost proportional to volume contraction of blood plasma , which is termed hypovolemia . ref http www.medterms.com script main art.asp?articlekey 3871 MedicineNet Definition of Hypovolemia Retrieved on July 2, 2009 ref ref http medical dictionary.thefreedictionary.com hypovolemia TheFreeDictionary.com hypovolemia Citing Saunders Comprehensive Veterinary Dictionary, 3 ed. Retrieved on July 2, 2009 ref Thus, it primarily affects the circulatory system , potentially causing hypovolemic shock . ECF volume contraction or hypovolemia is usually the type of volume contraction of primary concern in emergency, since ECF is approximately half the volume of ICF and is the first to be affected in e.g. bleeding . Volume contraction is sometimes even used synonymously with hypovolemia. ICF volume contraction Volume contraction of intracellular fluid may occur after substantial fluid loss, since it is much larger than ECF volume, or loss of potassium K sup sup see section below . ICF volume contraction may cause disturbances in various organs throughout the body. Dependence on lost solutes Na sup sup loss approximately correlates with fluid loss from ECF, since Na sup sup has a much higher concentration in ECF than ICF. In contrast, K sup sup has a much higher concentration in ICF than ECF, and therefore its loss rather correlates with fluid ... fluid loss See also Contraction alkalosis , the increase in blood pH that occurs as a result References ... more details
In physics , length contraction according to Hendrik Lorentz is the physical phenomenon of a decrease .... This contraction more formally called Lorentz contraction or Lorentz George FitzGerald Fitzgerald contraction is usually only noticeable at a substantial fraction of the speed of light the contraction ... History of special relativity Length contraction was postulated by George Francis FitzGerald 1889 and Hendrik ... the hypothesis of the stationary aether Lorentz ether theory Length contraction Lorentz FitzGerald contraction hypothesis . Although both FitzGerald and Lorentz alluded to the fact that electrostatic ... as of electromagnetic origin, and length contraction appeared to be a direct consequence of this model ... a dynamical explanation for length contraction. But this model was subject to the same problem as the original hypotheses Length contraction and the non electromagnetic forces were only invented ... that length contraction was no dynamical effect in the aether, but rather a kinematic effect due ... meaning of all relativistic effects in spacetime . So length contraction is not of Kinetics physics ... of the moving object. File Lorentzkontraktion.png thumb 300px right Symmetry of Lorentz contraction ... inertial frame is shorter than the proper length. This contraction only occurs in the line of motion ... the laws of nature must assume the same form in all inertial reference frames , length contraction ... in S and its length is contracted in S . Derivation Length contraction can simply be derived from the Lorentz ... length contraction.svg thumb left Minkowski diagram and length contraction. In S all events parallel ..., that length contraction can be regarded as a trigonometric phenomenon, with analogy to parallel slices ... See also Tests of special relativity Since the occurrence of length contraction depends on the inertial ... confirmations of Lorentz contraction are hard to achieve, because at the current sate of technology ... small to allow a direct measurement of contraction. However, there are indirect confirmations ... more details
Lanthanide contraction is a term used in chemistry to describe the decrease in ionic radius ionic radii of the chemical element elements in the lanthanide series from atomic number 58, Cerium to 71, Lutetium , which results in smaller than otherwise expected ionic radii for the subsequent elements starting with 72, Hafnium . ref name Housecroft Housecroft2nd pages 536, 649, 743 ref ref name Cotton Cotton&Wilkinson5th pages 776, 955 ref ref name Jolly Jolly, William L. Modern Inorganic Chemistry , McGraw Hill 1984, p.22 ref The term was coined by the Norwegian geochemist Victor Goldschmidt in his famous series Geochemische Verteilungsgesetze Der Elemente . ref name Goldschmidt Goldschmidt, Victor M. Geochemische Verteilungsgesetze Der Elemente , Part V Isomorphie Und Polymorphie Der Sesquioxyde. Die Lanthaniden Kontraktion Und Ihre Konsequenzen , Oslo, 1925 ref class wikitable Element Cerium Ce praseodymium Pr neodymium Nd promethium Pm samarium Sm europium Eu gadolinium Gd terbium Tb dysprosium Dy holmium Ho erbium Er thulium Tm ytterbium Yb lutetium Lu Atomic electron configuration br small all begin with Xe small 4f sup 1 sup 5d sup 1 sup 6s sup 2 sup 4f sup 3 sup 6s sup 2 sup 4f ... to lanthanide contraction . The ionic radius drops from 102 pm for cerium III to 86.1 pm for lutetium III . About 10 of the lanthanide contraction has been attributed to relativistic ... contraction, a chemical Separation process separation of lanthanides would be extremely difficult. However, this contraction makes the chemical separation of period 5 and period 6 transition metals of the same ... are influenced by the lanthanide contraction. The radii of the period 6 transition metals are smaller ... offset by the lanthanide contraction. ref name Cotton For example, the atomic radii of the metal ... discovered in 1789 . See also d block contraction or scandide contraction References references ... Category Lanthanides de Lanthanoidenkontraktion fr Contraction des lanthanides ko it Contrazione ... more details
About the rules of the English language English grammar the topic in mathematics, logic, and theoretical computer science Formal grammar linguistics In linguistics , grammar is the set of structural rules ... . Use of the term The term grammar is often used by non linguists with a very broad meaning indeed as Jeremy Butterfield puts it Grammar is often a generic way of referring to any aspect of English ... theory , for example, talks in terms of constraints , while Construction grammar , Cognitive grammar ... for using that language. This is a grammar, and&mdash at least in the case of one s native language&mdash ... Contemporary Linguistics ref The term grammar can also be used to describe the rules that govern the linguistic behaviour of a group of speakers. The term English grammar , therefore, may have several ... well defined variety of English such as Standard English . An English grammar is a specific description, study or analysis of such rules. A reference book describing the grammar of a language is called a reference grammar or simply a grammar. A fully explicit grammar that exhaustively describes the grammaticality grammatical constructions of a language is called a descriptive grammar. Linguistic ... the approaches is the traditional grammar which is traditionally taught in schools. The standard framework of generative grammar is the transformational grammar model developed in various ways by Noam Chomsky and his associates from the 1950s onwards. Etymology See grapheme The word grammar derives ..., to write . ref Citation last Harper first Douglas authorlink Douglas Harper title Grammar work Online Etymological Dictionary url http www.etymonline.com index.php?term grammar accessdate 8 April 2010 ... 2nd c. BC . In the West, grammar emerged as a discipline in Hellenism neoclassicism Hellenism ... extant work being the Art of Grammar lang grc , attributed to Dionysius Thrax ca. 100 BC . Latin grammar developed by following Greek models from the 1st century BC, due to the work ... more details
The collagen gel contraction assay is a type of wound healing wound contraction . It is performed using the dermal equivalent model, which consists of dermal fibroblast s seeded into a collagen gel. ref http www.springerlink.com content g518380278431706 Macrophages restrain contraction of an in vitro wound healing model ref References reflist DEFAULTSORT Collagen Gel Contraction Assay Category Skin physiology medicine stub ... more details
In chemistry, ring expansion and ring contraction are chemical reactions that increase or decrease, respectively, the number of atoms in a ring of a cyclic compound . Ring expansion reactions Examples of ring expansion reactions are the Beckmann rearrangement the Dowd Beckwith ring expansion reaction . the Tiffeneau Demjanov rearrangement the vinylcyclopropane cyclopentene rearrangement the Buchner ring expansion Ring contraction reactions Examples of ring contraction reactions are the Favorskii rearrangement the Demjanov rearrangement Ring contractions of cyclic ketone s and cycloalkene s brought about by hypervalent iodine ref Hypervalent Iodine Mediated Ring Contraction Reactions Luiz F. Silva, Jr Molecules journal Molecules 2006 , 11, 421 434 http www.mdpi.org molecules papers 11060421.pdf Online article ref for example the reaction of cyclohexene with iodosobenzene and boron trifluoride to cyclopentanecarbaldehyde Image HypervalentiodineRingContraction.png 300px Ring contraction initiated by hypervalent iodine References references Category Rearrangement reactions ... more details
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