Refimprove date December 2009 Annual cycle refers to the set of changes or events that uniformly, or consistently, take place at the same time of year. In biology , the annual cycle for plants and animals details behaviorial and chemical changes that take place as the seasons advance. ref McNamara, John M. and Houston, Alasdair I. 2008 Introduction Adaptation to the annual cycle Philosophical Transactions of the Royal Society of London B Biological Sciences 363 1490 pp. 209&ndash 210 ref In religion , the annual cycle refers to the various celebrations or memorials that occur in the same sequence from year to year. For example, Christianity has two annual cycles, the temporal cycle that tracks the events in the life of Christ , and the sanctoral cycle which tracks the various saint s days. Some Christian churches only observe the temporal cycle . ref Flesher, Paul http uwacadweb.uwyo.edu religionet er christ ctime.htm Christian Time and Worship Exploring Religions University of Wyoming ref In climatology , an annual cycle is the part of a measured quantity s fluctuation that is attributed to Earth s changing position in orbit over the course of the year. Such quantities might be influenced directly e.g. incoming solar radiation at a point at the surface or indirectly e.g. stratosphere stratospheric westerlies and polar easterlies easterlies over the winter and summer hemispheres, respectively by orbital position. Mathematically, the climatological annual cycle is commonly estimated from observational data or model output by taking the average of all Januaries, all Februaries, and so forth. If the observational record is long enough and conditions are stationary i.e. there is no significant long term trend , a meaningful annual cycle will result that can be used to calculate an anomaly time series . Notes Reflist DEFAULTSORT Annual Cycle Category Earth sciences biology stub reli stub climate stub zh ... more details
The Greek astronomer Hipparchus introduced two cycles that have been named after him in later literature. The first is described in Ptolemy s Almagest IV.2. Hipparchus constructed a cycle by multiplying by 17 a cycle due to the Chaldea n astronomer Kidinnu , so as to closely match an integer number of synodic month s 4267 , anomalistic month s 4573 , years 345 , and days 126007 about 1 hour it is also close to a half integer number of draconic month s 4630.53... , so it is an eclipse cycle . By comparing his own eclipse observations with Babylonian records from 345 years earlier, he could verify the accuracy of the various periods that the Chaldean astronomers used. The second is a calendar cycle Hipparchus proposed a correction to the Calippic cycle of 76 years , which itself was proposed as a correction to the Metonic cycle of 19 years . He may have published it in the book Peri eniaus ou meg thous On the Length of the Year , which is lost. From solstice observations, Hipparchus found that the tropical year is about 1 300 of a day shorter than the 365 1 4 days that Calippus used see Almagest III.1 . So he proposed to make a 1 day correction after 4 Calippic cycles, such that 304 years 3760 lunations 111035 days. This is a very decent approximation for an integer number of lunations in an integer number of days error only 0.014 days . But it is in fact 1.37 days longer than 304 tropical years the mean tropical year is actually about 1 128 day 11 minutes 15 seconds shorter than the Julian year calendar Julian calendar year of 365.25 days. These differences cannot be corrected with any cycle that is a multiple of the 19 year cycle of 235 lunations it is an accumulation of the mismatch between years and months in the basic Metonic cycle, and the lunar months need to be shifted systematically by a day with respect to the solar year i.e. the Metonic cycle itself needs to be corrected after every 228 years. Greek astronomy DEFAULTSORT Hipparchic Cycle Category Ancient Gr ... more details
Unreferenced date October 2008 Merge from The Tomb novel The Touch Wilson novel Reprisal novel date November 2010 The Adversary Cycle is a series of six novel s written by United States American author F. Paul Wilson . Originally known as The Nightworld Cycle this name is even printed in the front of some early editions of Nightworld , John Clute , in his section on F. Paul Wilson s work in The Encyclopedia of Science Fiction , kept referring to the Adversary. The author liked that better and so renamed the cycle Citation needed date October 2008 . Novels in the Cycle The six novels that comprise The Adversary Cycle are in chronological order The Keep F. Paul Wilson novel The Keep , August 1981, ISBN 0688006264 The Tomb novel The Tomb , November 1984, ISBN 0918372127 The Touch Wilson novel The Touch , June 1986, ISBN 0 399 13144 2 Reborn novel Reborn , March 1990, ISBN 0 913165 52 2 Reprisal novel Reprisal , July 1991, ISBN 0 913165 59 X Nightworld novel Nightworld , May 1992, ISBN 0 450 53665 3 Interestingly, The Tomb and The Touch were initially written as stand alone novels it is only in Nightworld that they were retroactively made part of the Cycle as their respective protagonists all come together to fight the final battle against the Otherness. Although these six books make up the core of The Adversary Cycle , many more novels and short stories tie into the series. For example The Tomb is also the start of the Repairman Jack series of novels, which quickly became deeply entwined in the Adversary Cycle. They take place in the last three years before Nightworld and include some of the main characters from the original Adversary Cycle. This is all part of the Grand Unification theme of Wilson s work. The Adversary Cycle series DEFAULTSORT Adversary Cycle, The Category Novel series Horror novel stub ... more details
In astronomy and calendar studies, the Callippic cycle or Calippic is a particular approximate Least common multiple common multiple of the year specifically the tropical year and the Month Synodic month synodic month , that was proposed by Callippus in 330 BC . It is a period of 76 years, as an improvement on the 19 year Metonic cycle . A century before Callippus, Meton discovered the cycle of 19 ... day 365d 6h 00m 00s , so he multiplied the 19 year cycle by 4 to reach an integer number of days, and then dropped 1 day from the last 19 year cycle. Thus he constructed a cycle of 76 years that contains 940 lunations and 27,759 days, and has been called the Callippic after him. Although the cycle ..., in other words the cycle drifts another day late per 130 10 11 years, which is considerably worse than the drift of the unrounded Metonic cycle . If the Callippic cycle is considered as closer to its ... as the unrounded Metonic cycle within a few seconds per year . If it is taken as 940 lunations less ... it grossly too short, and it will also grossly drift ahead with respect to the mean lunar cycle at the rate of 1 940 of a day 1 minute 31 seconds per lunar month. If the cycle length is truncated to 27,758 ... per year, and it will drift ahead of the mean lunar cycle by about 3 4 940 day 1 minute 9 seconds per lunar month. Altogether, the purported accuracy of this cycle is not impressive, but it is of historical interest. The first year of the first Callippic cycle began at the summer solstice of 330 BC ... of the first Callippic cycle 283 BC , when on the eighth of Anthesterion , the Pleiades star cluster Pleiades were Occultation occulted by the Moon . ref name Evans Evans, James. The Callippic Cycle ... calendar . Also Hipparchus invented his own Hipparchic cycle Hipparchic calendar cycle as an improvement upon the Callippic cycle. Ptolemy s Almagest provided some conversions between the Callippic ... Callippic calendar converter as used in Ptolemy s Almagest Greek astronomy DEFAULTSORT Callippic Cycle ... more details
The Cheng Cycle is a patented technology for converting new and existing simple cycle gas turbines to highly ... off shore need for such technology in new and exisitng power plants . The Cheng Cycle combines the Brayton cycle of the gas turbine with the Rankine steam cycle in a parallel process, dual fluid flow path ref http www.chengcycle.com ref . The Cheng Cycle incorporates full heat recovery massive ... patents US6644011 ref . The Cheng Cycle has a small plant footprint area, produces very low emissions ... Cycle at high temperatures and altitudes, and the Cheng Cycle offers higher part load efficiency, which ... Cycle File Figure 1 Cheng Cycle.png thumb Basic Arrangement & Flow Paths of the Cheng Cycle Figure 1 shows the basic arrangement and flow paths of the Cheng Cycle . The waste energy from the gas turbine cycle is used as the heat source to generate steam to be injected into the gas turbine combustion ..., boosting the power output and efficiency of the plant. The Cheng Cycle offers efficiencies equaling and capacities exceeding those of the combined cycle plant for the underlying simple cycle engine type ... and auxiliaries of the combined cycle plant ref http www.sciencedirect.com science article pii S019689049600204X ref . When coupled with a multiple effect distillation plant, the Cheng Cycle is the most ... coastal areas. The Cheng cycle has been well documented and are in widespread use. Since 1983, about 100 variants of the original Cheng cycle engines have been installed at more than 60 sites around ... Cycle plant, the GE 7LM2500 ACS operated by the Kaua i Island Utility Cooperative at the Kapaia Power ... inlet temperature for the Cheng Cycle maximizes the thermal efficiency of the system at any given load ... graph is the operating line of the Cheng Cycle control system ref http alexandria.tue.nl repository books 438893.pdf ref . It is important to note that the Cheng Cycle observes the original equipment ..., shaft torque and firing or turbine inlet temperatures. Thus, the Cheng Cycle does not impose unacceptable ... more details
thermodynamics cTopic Processes and Cycles A transcritical cycle is a thermodynamic cycle where the working fluid goes through both subcritical and Supercritical fluid supercritical states. This is often the case when carbon dioxide , CO sub 2 sub , is the refrigerant . The modern transcritical cycle was developed in 1988 1991 by the Norwegian professor Gustav Lorentzen scientist Gustav Lorentzen 1915 1995 and his team. ref Shecco Synergies, Hydro, Oslo 2003. www.shecco.com ref See also EcoCute References references Thermodynamic cycles Category Thermodynamics Category Condensed matter physics Category Phases of matter chem stub fr Cycle transcritique it Ciclo transcritico ... more details
Orphan date February 2009 Wikify date April 2010 Information cycle is the progression of events over time as being processed by media. For example, a story event goes through a series of stages as it evolves by media presented first by the Web, TV, Radio, newspapers, magazines, scholarly journals, and eventually comes into books. Just to stub. Please, clean up See also Information Research Publication cycle External links http www.libraries.psu.edu content dam psul up lls audiovideo infocycle 2008.swf Information cycle http www.lib.washington.edu uwill research101 Research 101 http www.lib.utah.edu instruction leap infocycleprimer.htm Primer on the Information Cycle Category Research Category Information culture stub ... more details
In graph theory , a peripheral cycle in a graph G is a cycle that is Glossary of graph theory Subgraphs induced and non separating ref cite book last Diestel first Reinhard title Graph Theory year 2010 publisher Springer Verlag isbn 978 3 642 14278 9 url http diestel graph theory.com ref . That is, it is a cycle C such that no two vertices in C are connected by an edge not in C and the graph G &minus C we are deleting vertices of C and all incident edges is connected. Properties In a Connectivity graph theory 3 connected planar graph , boundaries of faces are precisely the peripheral cycles. The cycle space of a 3 connected graph is generated by the peripheral cycles a result of Tutte, 1963 . References reflist Category Graph theory ... more details
A diurnal cycle is any pattern that recurs every 24 hours as a result of one full rotation of the Earth . ref http en.mimi.hu meteorology diurnal cycle.html ref In climatology , the diurnal cycle is one of the most basic forms of climate pattern s. The most familiar such pattern is the diurnal temperature variation . Such a cycle may be approximately sinusoidal , or include components of a Truncated distribution Definition truncated sinusoid due to the sun s rising and setting . Practical Example In telecommunications, the daily temperature cycle from the sun warming the earth causes a diurnal sinusoidal phase shift as the fiber optics or wire cabling expands and contracts. See also Circadian rhythm Diel vertical migration References Reflist Climate oscillations Category Climate patterns climate stub de Tagesgang nl Dagelijkse gang ... more details
Image Cycle button example.png frame right A cycle button A cycle button is a graphical user interface elements of graphical user interfaces element that allows the user to choose one from a predefined set of options ref name uf cite web url http www.usabilityfirst.com glossary cycle button title Cycle button work Usability Glossary publisher Usability First accessdate 2011 06 25 ref . It is used as a button computing button ref name uf the content of which changes with each point and click click ref name uf and cycles between two or more values ref name uf the currently displayed value is the user s choice. A cycle button s advantage over radio button s or a list box is that it takes less screen space ref name uf its advantage over a drop down list is that a single mouse click is enough to switch between the two options. However, a disadvantage is that, if the button has a lot of options, a lot of clicks are needed to switch to the desired one. This is why some GUI environments have the ability to display the same element as a cycle button or a drop down list, depending on the number of options. References reflist GUI widgets Category GUI widgets GUI stub ... more details
Image Cori & Alanine Cycle edited by wrekodara.svg right thumb 500px Alanine & Cori cycles Image L alanine skeletal.svg thumb alanine Image Pyruvic acid 2D skeletal.png thumb pyruvate Image Beta D Glucose.svg thumb glucose The alanine cycle is quite similar to the Cori cycle . When muscles produce lactic acid lactate during times of decreased oxygen, they also produce alanine . This alanine is shuttled to the liver where it is used to make glucose . The alanine cycle is less productive than the Cori Cycle, which uses lactate, since a byproduct of energy production from alanine is production of urea . Removal of the urea is energy dependent,requiring four high energy phosphate bonds 3 ATP hydrolyzed to 2 ADP and one AMP , thus the net ATP produced is less than that found in the Cori Cycle. However, unlike in the Cori Cycle, NADH is conserved because lactate is not formed. This allows for it to be oxidized via the electron transport chain . This pathway requires the presence of alanine aminotransferase , which is restricted to tissues such as muscle , liver , and the intestine . Therefore, this pathway is used instead of the Cori Cycle only when an aminotransferase is present and when there is a need to transfer ammonia to the liver. Alanine cycle also serves other purposes Recycles carbon skeletons between muscle and liver Transports ammonium to the liver and is converted into urea. External links http www.colorado.edu intphys Class IPHY3430 200 image figure14m.jpg Diagram at colorado.edu http themedicalbiochemistrypage.org amino acid metabolism.html alaninecycle at indstate.edu Unreferenced date April 2007 Glycolysis enzymes DEFAULTSORT Alanine Cycle Category Metabolic pathways biochemistry stub cs Alaninov cyklus de Cori Zyklus Glukose Alanin Zyklus es Ciclo de Cahill id Lintasan alanina ja pl Cykl glukozowo alaninowy pt Ciclo da glicose alanina sv Alanincykeln vi Chu tr nh Alanine zh ... more details
A cycle count is an inventory auditing procedure, which falls under inventory management, where a small subset of inventory, in a specific location, is counted on a specified day. Cycle counts contrast with traditional physical inventory in that a full physical inventory may stop operation at a facility while all items are counted at one time. Cycle counts are less disruptive to daily operations, provide an ongoing measure of inventory accuracy and procedure execution, and can be tailored to focus on items with higher value, higher movement volume, or that are critical to business processes. Cycle counting should only be performed in facilities with a high degree of inventory accuracy greater than 95 . The purpose of cycle counting is to verify the inventory accuracy and is not an adequate procedure to be used to correct inventory errors. ABC analysis Most cycle counting applications use ... principle , is to cycle count inventory by percentage of inventory value cost multiplied by usage ... to halt while a minor component is re ordered. Cycle counting by usage only Cycle counting by usage ... to satisfy accounting requirements. Hybrid Most cycle counting frequencies are determined first by Pareto ... efficient and accurate cycle counts, many organizations use some form of software to implement ..., these selections are daily but many companies choose to generate cycle count items weekly. Many companies perform mini physical inventories and call it cycle counts. Instead of using random or system ... alternative to true cycle counting where a company may not have the sophistication to utilize cycle counting software. Dangers Cycle counts can introduce inventory errors if the cycle count process ... each contribute to these error. This error is mitigate with correct cycle count procedures that specify not only the part number to be counted but also the location it should be in. Cycle counting ... accuracy. References references DEFAULTSORT Cycle Count Category Distribution, retailing, and wholesaling ... more details
thermodynamics cTopic Processes and Cycles Image Cyclic process.PNG thumb 300px left A general thermodynamic cycle A Scuderi cycle is a thermodynamic cycle is constructed out of the following series of thermodynamic process es ref cite web url http www.greencarcongress.com 2009 09 scuderi iaa 20090908.html title Scuderi Group Will Present Results from Split Cycle Prototype Testing at IAA publisher Green Car Congress date 2009 09 08 accessdate 2010 09 22 ref A B and C D TOP and BOTTOM of the loop a pair of quasi parallel adiabatic process es D A LEFT side of the loop a positively sloped, increasing pressure, increasing volume process B C RIGHT side of the loop an isochoric process The adiabatic processes are impermeable to heat heat flows rapidly into the loop through the left expanding process resulting in increasing pressure while volume is increasing some of it flows back out through the right depressurizing process the heat that remains does the work. clear References reflist Thermodynamic cycles DEFAULTSORT Scuderi Cycle Category Thermodynamics Category Thermodynamic cycles ... more details
Infobox comics elements Wikipedia WikiProject Comics name Super Cycle image filename format only imagesize default 250 caption publisher DC Comics debut Forever People 1 creators Jack Kirby vehicle supports Forever People , Young Justice subcat DC Comics sortkey Super Cycle The Super Cycle is a fictional device from DC Comics , created by Jack Kirby for his Jack Kirby s Fourth World Fourth World series The Forever People . Decades after, it was appeared another Super Cycle in 1990 s Young Justice series. History The Super Cycle is a piece of quasi living New Genesis technology it resembles a small three wheeled car, rather than a motorcycle, and can carry several passengers. Despite having an open top, it can travel at supersonic speeds on the ground or by flying without harm to its passengers using electrons it can also turn itself and its passengers intangible. Another Super Cycle was discovered by Young Justice ref Young Justice 1, September 1998 ref and was used as their mode of transportation for a time. The two cycles act irrationally at the same time. The Young Justice s one flees on its own, while the Forever People s one has a transforming fit and almost kills Beautiful Dreamer. It is revealed that their erratic behavior was the result of a mating cycle. The two cycles have their own equivalent of sex, which immediately results in the creation of a baby cycle named Kirby , in obvious honor of Jack Kirby. The Young Justice Super Cycle returns to Earth with the team, while the Forever People s Cycle and the baby remain on New Genesis. It is seen in the mini series, Death of the New Gods 4 2008 outside the Forever People s headquarters. Superman , Orion , and Mister ... People had been slain many weeks ago. In other media Television The Super Cycle makes its first animated ... www.comicvine.com super cycle 29 70704 Super Cycle on ComicVine http dc.wikia.com wiki Super Cycle Super Cycle on DC Database Wiki http www.dcuguide.com who.php?name supercycle Super Cycle on DCU ... more details
About broader pattern of violence and intergenerational cycle of violence the social cycle theory within one couple s pattern of abuse Cycle of abuse The term cycle of violence refers to repeated and dangerous ... abuse types signs causes effects.htm cycle The cycle of violence. Domestic Violence and Abuse ... date November 2011 The pattern, or cycle, repeats and can happen many times during a relationship. ref ... and then repeated as an adult, therefore continuing on in a perceived cycle. ref Fagan, A. A. 2005 . The Relationship ... Cycle of Violence. Journal of Family Violence. 20 5 279 290. ref Cycle of violence within a relationship A cycle of abuse generally follows the following pattern ref name HELP Abuse &ndash ... November 20, 2011. ref A general, intricate and complicated cycle of traumatic violence and healing ..., 2011. ref Intergenerational cycles of violence Intergenerational cycle of violence &ndash violence ... 1 11.htm Intergenerational Cycle Of Abuse AbusiveLove.com. Retrieved November 21, 2011. ref Children ... and or physically. Thirty to 50 of dating relationships can exhibit the same cycle of escalating violence ... begets violence References Reflist Further reading Books Beverly Engel Engel, Beverly Breaking the Cycle ..., Latifah Suffering In Silence Breaking the Cycle of Abuse 2006 Hegstrom, Paul Angry Men and the Women Who Love Them Breaking the Cycle of Physical and Emotional Abuse 2004 Herbruck, Christine Comstock Breaking the cycle of child abuse 1979 Marecek, Mary Breaking Free from Partner Abuse Voices of Battered Women Caught in the Cycle of Domestic Violence 1999 Mills, Linda G. Violent Partners A Breakthrough Plan for Ending the Cycle of Abuse 2008 Ney, Philip G. & Peters, Anna Ending the Cycle of Abuse ... 1995 Pugh, Roxanne Deliverance from the Vicious Cycle of Abuse 2007 Quinn, Phil E. Spare the Rod Breaking the Cycle of Child Abuse Parenting Social Concerns and Issues 1988 Smullens, SaraKay Setting Yourself Free Breaking the Cycle of Emtional Abuse in Family, Friendships, Work and Love 2002 Waldfogel ... more details
thermodynamics cTopic Processes and Cycles This article is about the adiabatic Stirling cycle . For the idealized Stirling cycle , see the Stirling engine The Stirling cycle Stirling engine article. The Stirling cycle is a thermodynamic cycle that describes the general class of Stirling devices. This includes ... publisher L.A. Mair year 1999 isbn 0 9526417 0 4 ref The cycle is reversible, meaning that if supplied ... for cryogenic cooling. The cycle is defined as a closed cycle regenerator regenerative cycle with a gas eous working fluid. Closed cycle means the working fluid is permanently contained within the thermodynamic ... regenerator which increases the device s thermal efficiency . The cycle is the same as most other ... Stirling cycle thermodynamics Image Stirling Cycle color.png thumb A Pressure volume diagram pressure volume graph of the idealized Stirling cycle. In real applications of the Stirling cycles e.g. Stirling engines this cycle is quasi elliptical. The idealized Stirling cycle consists of four ... for use in the next cycle. li Isothermal Gas compression Compression . The compression space ... of topic The Stirling cycle is a highly advanced subject that has defied analysis by many experts for over 190 years. Highly advanced thermodynamics are required to describe the cycle. Professor Israel Urieli writes ...the various ideal cycles such as the Schmidt cycle are neither physically realizable nor representative of the Stirling cycle ref Organ, The Regenerator and the Stirling Engine ... in the Stirling cycle is judged by Jakob to rank nowiki nowiki among the most difficult and involved ... Stirling cycle Most thermodynamic textbooks use a highly simplified form of a Stirling cycle consisting of 4 processes. This is known as an ideal Stirling cycle , because it is an idealized model, and not necessarily an optimized cycle. Theoretically, the ideal cycle does have high net work output per cycle. However, it is rarely used for practical reasons, in part because other cycles are simpler ... more details
Refimprove date December 2009 During World War II , Operation Cycle was the evacuation of Allies of World War II Allied troops from Le Havre , France at the end of the Battle of France . From 10 to 13 June 1940, 11,059 British and Allied forces were evacuated. As the line on the Somme was breached, the 1st Armoured Division United Kingdom British 1st Armoured and the 51st Highland Infantry Division s, along with French units tried to fall back to the coast. Part of these groups made it, and despite the loss of the personnel ship HMS Bruges were evacuated by British destroyers and other craft. As part of Cycle, an attempt to rescue the remaining men along a line from St. Valery en Caux to Veules was conducted on 10 11 June. It was only partially successful, since thick fog hampered operations. A total of 2137 British and 1184 French soldiers were removed, but the remainder, including over 6000 men of the Highland Division, were captured. ref cite web url http www.historyofwar.org articles operation cycle.html title Operation Cycle, the evacuation from Havre, 10 13 June 1940 publisher Historyofwar.org date accessdate 2011 08 18 ref Cycle was preceded by the better known Operation Dynamo , the rescue of 338,226 British and French soldiers from Dunkirk from 26 May to 4 June, and followed by Operation Ariel , over 215,000 soldiers embarking from Cherbourg , St. Malo , and other ports between June 14 and 25. References Reflist coord missing DEFAULTSORT Cycle Category Battle of France Category Evacuations es Operaci n Cycle fr Op ration Cycle nl Operatie Cycle ja fi Operaatio Cycle ... more details
Image Water cycle.png thumb 320px right A commonly cited example is the water cycle . In geography and Earth science , a biogeochemical cycle or substance turnover or cycling of substances is a pathway ... , atmosphere , and hydrosphere compartments of Earth . A cycle is a series of change which comes back ... and physical world are known as biogeochemical cycle. In effect, the element is recycled, although ... through the water cycle, as shown in the diagram. The water undergoes evaporation , condensation ... as a part of the system, for example the water cycle, the carbon cycle, the nitrogen cycle, etc ... a part of living organisms, these chemical elements also cycle through abiotic factors of ecosystems ... tube worm . In the sulfur cycle , sulfur can be forever recycled as a source of energy ... idls carboncycle.htm Biogeochemical Cycles Carbon Cycle. ref When chemicals are held for only short ... the carbon cycle , the nitrogen cycle , the oxygen cycle , the phosphorus cycle , the sulfur cycle , and the water cycle . There are many biogeochemical cycles that are currently being studied ... the mercury cycle ref http wi.water.usgs.gov mercury mercury cycling.html Mercury Cycling in the Environment. USGS. October 17, 2008. ref , and the human caused cycle of atrazine , which may affect certain ..., the study of these is inherently multidiciplinary. The carbon cycle may be related to research in ecology ... 180 lines 2 Image Nitrogen Cycle.jpg alt1 Diagram of the nitrogen cycle Nitrogen cycle Image Water cycle.png alt2 Diagram of the water cycle Water cycle Image Carbon cycle cute diagram.svg alt3 Diagram of the carbon cycle Carbon cycle Image Oxygen cycle.svg alt4 Diagram of the oxygen cycle Oxygen cycle Image phoscycle EPA.jpg alt5 Diagram of the phosphorus cycle Phosphorus cycle See also Portal ... Ecology Ecosystem Natural environment Nature Recycling ecological Sulfur Cycle References Reflist Biogeochemical cycle state expamded modelling ecosystems DEFAULTSORT Biogeochemical Cycle Category Biogeochemical ... more details
. Category Theban Cycle Category Lost poems ca Cicle teb de Thebanischer Zyklus el es Ciclo tebano fr Cycle th bain id Siklus Thebes it Ciclo Tebano ja ... more details
Unreferenced stub auto yes date December 2009 Orphan date December 2009 The glucose cycle also known as the hepatic futile cycle occurs primarily in the liver and is the dynamic equilibrium between glucose and glucose 6 phosphate . This is important for maintaining a constant concentration of glucose in the blood stream . Function The glucose cycle is required for one of the liver functions the homeostasis of glucose in the blood stream. When blood glucose levels are in excess, glucose can be stored in the liver as glycogen . When glucose levels in the blood stream are low the glycogen can be catabolism catabolised and glucose may re enter the blood stream. The catabolic process occurs at the nonreducing end of glycogen. A phosphate group breaks the bond between C 1 of a glucose ring and the O that connects it to the next phosphorolysis . One glucose unit is thus split off. Glycogen with n glucose units is converted into G 1 P a PO sub 4 sub group now attaches to C1 where O used to and glycogen with n 1 glucose units by enzyme glycogen phosphorylase. G 1 P is then converted into G 6 P by enzyme phosphoglucomutase. A water molecule hydrolyses G 6 P to glucose, the enzyme is glucose 6 phosphatase. Cell specificity When glucose enters a cell it is rapidly changed to glucose 6 phosphate, by hexokinase or glucokinase . The glucose cycle can occur in liver cells due to a liver specific enzyme glucose 6 phosphatase , which catalyse the dephosphorylation of glucose 6 phosphate back to glucose. Glucose 6 phosphate is the product of glycogenolysis or gluconeogenesis , where the goal is to increase .... Regulation of glucose cycle Flux through the glucose cycle is regulated by several hormones ... 6 phosphatase. Diseases associated with glucose cycle A deficiency in glucose 6 phosphatase that disrupts the liver glucose cycle, can lead to Glycogen storage disease type I von Gierke s disease . DEFAULTSORT Glucose Cycle Category Metabolic pathways Biochem stub ... more details
The Humphrey cycle is a thermodynamic cycle similar to the pulse detonation engine cycle. It may be considered to be a modification of the Brayton cycle in which the constant pressure heat addition process of the Brayton cycle is replaced by a constant volume heat addition process. ref name Heiser Heiser, W. H. and Pratt D. T. Thermodynamic Cycle Analysis of Pulse Detonation Engines, Journal of Propulsion and Power, Vol. 18, No. 1, January February 2002 ref Hence, the ideal Humphrey cycle consists of 4 processes Reversible, adiabatic isentropic compression of the incoming gas. During this step incoming gas is compressed, usually by turbomachinery , in such a way that no losses of stagnation pressure or heat occur. The pressure and density of the gas increase. Constant volume heat addition. In this step, heat is added while the gas is kept at constant volume. In most cases, Humphrey cycle engines are considered open cycles meaning that air flows through continuously , so this means that the specific volume or density remains constant throughout the heat addition process. Heat is usually added by combustion. Reversible, adiabatic isentropic expansion of the gas. During this step incoming gas is expanded, usually by turbomachinery , in such a way that no losses of stagnation pressure or heat occur. The pressure and density of the gas decrease. Constant pressure heat rejection. In this step, heat is removed from the working fluid while the fluid remains at constant pressure. In open cycle engines this process usually represents expulsion of the gas from the engine, where it quickly equalizes to ambient pressure and slowly loses heat to the atmosphere, which is considered to be an infinitely large reservoir for heat storage, with constant pressure and temperature. References reflist Thermodynamic cycles Category Thermodynamic cycles ... more details
File Limit cycle Poincare map.svg thumb 250px right Attracting limit cycle and its Poincar map In mathematics , in the area of dynamical systems , a limit cycle on a plane or a two dimensional manifold the original definition is not valid in 3D, since the periodic orbit could be neutrally stable and non isolated along the 3d direction is a closed trajectory in phase space having the property that at least one other trajectory spirals into it either as time approaches infinity or as time approaches negative infinity. Such behavior is exhibited in some nonlinear systems . In the case where all the neighbouring trajectories approach the limit cycle as time approaches infinity, it is called a stable manifold stable or attractive limit cycle limit cycle . If instead all neighbouring trajectories approach it as time approaches negative infinity, it is an unstable or non attractive limit cycle limit cycle . Stable limit cycles imply self sustained oscillations . Any small perturbation from the closed trajectory would cause the system to return to the limit cycle, making the system stick to the limit cycle. Image VanDerPolPhaseSpace.png right 250px thumb Stable limit cycle for the Van der Pol oscillator As seen in the figure, trajectories for various initial states of this system converge to the limit cycle. Hence, this system exhibits self sustained oscillations. The number of limit cycles of a polynomial differential equation is the main object of the second part of Hilbert s sixteenth problem . Bendixson Dulac theorem Bendixson s theorem and the Poincar Bendixson theorem predict the absence or existence, respectively, of limit cycles of two dimensional nonlinear dynamical systems. See also Periodic point Stable manifold Hyperbolic set References planetmath reference id 6722 title limit cycle Steven H. Strogatz, Nonlinear Dynamics and Chaos , Addison Wesley publishing ... Limit sets ar fr Cycle limite it Ciclo limite nl Limietcykel ja pl Cykl ... more details
A duty cycle is the time that an entity spends in an active state as a fraction of the total time under consideration. ref http www.its.bldrdoc.gov fs 1037 dir 013 1849.htm Definition duty cycle , Institute ... potentials by neurons . In an electrical device, a 60 duty cycle means the power is on 60 of the time and off 40 of the time. The on time for a 60 duty cycle could be a fraction of a second or for say ... of time it takes for the device to go through a complete on off cycle. The term duty cycle has no agreed meaning for aperiodic devices. Citation needed date January 2012 Definition Image PWM duty cycle with label.gif thumb 350px The duty cycle D is defined as the ratio between the pulse duration math tau math and the period math Tau math of a rectangular waveform In a periodic event, duty cycle is the ratio of the duration of the event to the total period of a signal. duty cycle math D frac tau ... pulses , the duty cycle is the pulse duration divided by the pulse period . ref http www.aubraux.com jitter meas clock positive duty cycle.php Clock Positive Duty Cycle , Aubrax, accessed 2011 ... has a duty cycle of 25 . The pulse duration is normally calculated for positive pulses unless negative duty cycle is specified. The duty cycle of a non rectangular waveform, such as a sine or triangle ..., or 1 100 of the time, and therefore its duty cycle is 1 100, or 1 percent. ref http www.electricmotors.machinedesign.com ... 2011 03 23 ref In electronic music, music synthesizers vary the duty cycle of their audio frequency ... modulation PWM . In the printer copier industry, the duty cycle specification refers to the rated ... cycle is defined as the percentage of time in a 10 minute period that it can be operated continuously before overheating. ref http www.zena.net htdocs FAQ dutycycle.shtml What does the term duty cycle ... to describe the activity of neurons and muscle fibers . In a neural network for example, a duty cycle specifically refers to the proportion of a cycle period in which a neuron remains active. ref name ... more details
In differential geometry , a Hodge cycle or Hodge class is a particular kind of homology class defined on a complex number complex algebraic variety V , or more generally on a K hler manifold . A homology class x in a homology group H sub k sub V , C H where V is a non singular complex algebraic variety or K hler manifold is a Hodge cycle , provided it satisfies two conditions. Firstly, k is an even integer 2 p , and in the direct sum of modules direct sum decomposition of H shown to exist in Hodge theory , x is purely of type p , p . Secondly, x is a rational class, in the sense that it lies in the image of the abelian group homomorphism H sub k sub V , Q &rarr H defined in algebraic topology as a special case of the universal coefficient theorem . The conventional term Hodge cycle therefore is slightly inaccurate, in that x is considered as a class Modulo jargon modulo boundaries but this is normal usage. The importance of Hodge cycles lies primarily in the Hodge conjecture , to the effect that Hodge cycles should always be algebraic cycle s, for V a complete algebraic variety . This is an unsolved problem, as of 2010 lc on it is known that being a Hodge cycle is a necessary condition to be an algebraic cycle that is rational, and numerous particular cases of the conjecture are known. References Springer id h h047460 title Hodge conjecture Category Hodge theory ... more details
The learning cycle is a research supported method for education , particularly in science ref http www.coe.ilstu.edu scienceed lorsbach 257lrcy.htm The Learning Cycle as a Tool for Planning Science Instruction ref . The learning cycle has five overlapping phases Engage in which a student s interest is captured and the topic is established. Explore in which the student is allowed to construct knowledge in the topic through facilitated questioning and observation. Explain in which students are asked to explain what they have discovered, and the instructor leads a discussion of the topic to refine the students understanding. Extend in which students are asked to apply what they have learned in different but similar situations, and the instructor guides the students toward the next discussion topic. Evaluate in which the instructor observes each student s knowledge and understanding, and leads students to assess whether what they have learned is true. Evaluation should take place throughout the cycle, not within its own set phase. Methods of implementing the learning cycle Engage Use of anecdotes that relate to subject. Explore Allow discussion that students discover answers instead of just hearing answers. Explain Students are required to reword what they have learned to demonstrate their knowledge. Extend Take the principles taught and have students apply the knowledge in another area or facet of the subject. Evaluate Observe and correct each student individually to perfect their working knowledge of the subject. References references DEFAULTSORT Learning Cycle Category Learning Edu stub ... more details
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