Position (vector) - Revision history

en>Cmglee: /* References */ Add {{Classical mechanics derived SI units}}

2014-11-10T00:25:44Z

References: Add {{Classical mechanics derived SI units}}

← Older revision		Revision as of 02:25, 10 November 2014
Line 1:		Line 1:
	~~{{unreferenced\|date=January 2011}}~~		One of these options has a chance of producing healing. If at any point of time, you are being told that you suffer from a mental illness, don't believe them. Obsessing about details that seem unimportant to others. Once you have a list of 10 items prioritize these in order of your preference, the best one first. Garth, 41, said early fame was overwhelming, to the point where she felt paralyzed and didn't want to leave the house. <br><br>Again, there are some great resources online for you to look into and I hope you do. Do you ever daydream or imagine something bad is going to happen. If, for example, a child lives in a home where they are exposed to math, they will grow up and most likely acquire good math skills. At the hospital said they had had symptoms of panic attacks and that over time could have been the re symptoms from anticipatory anxiety, or that events similar to that triggered the panic attack could have the ability to make him wake anxiety disorder symptoms. Want your child to triumph over social anxiety child disorder; The Anxiety Free. <br><br>A certain humming sound or a continuous sound can make the person lose his balance. Considering medication can make adverse reactions, various most people with anxiety disorder are afraid to take them owing to anxieties about brief and long phrase facet outcomes. The Valerian root in the tea decreased my anxiety like nothing I had ever found. Perhaps you find it hard to believe that water can have that much of an effect on how you feel and your state of mind. If there is nothing you can do, will yourself to stop worrying and even thinking about whatever worries you. <br><br>In a society like ours, they are often seen as loners, anti-socials, or wallflowers. Luckily, anxiety is a treatable disorder and there are many ways to help your teen. You should definitely learn the way long you'll have to take the drug. It is likely the case that your attention is less drawn to your emotional wellbeing and spiritual needs. When there is danger, these sad messengers are true life-savers, alerting the body into action to prevent harm. <br><br>What should be important to you is not the type of anxiety you suffer from but how soon it can be cured. The purpose of by means of diversion, for people who desire to live anxiety free, is to have new experiences that capture the person. thousands people feel far preferable about heading to a real person but for thousands of us this is simply not an alternative irrespective of whether it be from the money standpoint or perhaps a standpoint from the distress of one more human knowing our deficiencies. Before you hit the sheets at night, you should think about all of the great stuff that is occurring in your life right now. The need for you to recognize how to prevent and deal with anxiety attack cannot be exaggerated.<br><br>In case you loved this information and you would like to receive much more information concerning [http://www.stress-lavoro-correlato.info/sitemap/ anxiety medicines] please visit the page.
	~~'''Isochron dating''' is~~ a ~~common technique~~ of ~~[[radiometric dating]] and is applied to date certain events~~, ~~such as [[crystal]]lization~~, ~~[[metamorphism]], shock events, and differentiation of precursor melts, in the history of [[rock (geology)\|rocks]]~~. ~~Isochron dating can be further separated into ''mineral isochron dating'' and ''whole rock isochron dating''; both techniques are applied frequently~~ to ~~date terrestrial and also extraterrestrial rocks ([[meteorite]]s)~~. ~~The advantage of isochron dating as compared to simple radiometric dating techniques is that no assumptions are needed about the initial amount~~ of ~~the daughter [[nuclide]]~~ in ~~the [[radioactive decay]] sequence. Indeed the initial amount~~ of the ~~daughter product can be determined using isochron dating. This technique can be applied if the daughter element has at least~~ one ~~stable [[isotope]] other than the daughter isotope into which the parent nuclide decays~~.

	~~==Basis for method==~~

	~~All forms of isochron dating assume that the source of the rock or rocks contained unknown amounts of both [[radiogenic]] and non-radiogenic isotopes of the daughter element~~, ~~along with some amount of the parent nuclide. Thus~~, ~~at the moment of crystallization~~, the ~~ratio of the concentration of the radiogenic isotope of the daughter element~~ to ~~that of the non-radiogenic isotope is some value independent of the concentration of~~ the ~~parent~~. ~~As time goes on~~, some ~~amount of the parent decays~~ into ~~the radiogenic isotope of the daughter~~, ~~increasing the ratio of the concentration of the radiogenic isotope~~ to ~~that of the daughter. The greater the initial concentration of the parent~~, ~~the greater the concentration of the radiogenic daughter isotope~~ will ~~be at some particular time~~. ~~Thus,~~ the ~~ratio~~ of the ~~daughter to non-radiogenic isotope will become larger with time~~, ~~while the ratio of parent~~ to ~~daughter will become smaller. For rocks~~ that ~~start out with a small concentration of~~ the ~~parent,~~ the ~~daughter/non-radiogenic ratio will not change quickly as compared~~ to ~~rocks starting with a large concentration of the parent~~.

	~~==Isochron plots==~~

	~~To perform dating, a rock is crushed~~ to a fine powder and minerals are separated by various physical and magnetic means. Each mineral has different ratios between parent and daughter concentrations. For each mineral, the ratios are related by the following equation:

	~~:<math>{ D+\Delta{P}_t \over D_i } =~~
	~~{\Delta{P}_t \~~over ~~P-\Delta{P}_t } \left ( { P-\Delta{P}_t \over D_i }\right ) + {D \over D_i}</math> &nbsp~~;~~        (1)~~

	~~where~~

	:<~~math~~>D<~~/math~~> is the ~~initial concentration of the daughter isotope,~~

	~~:<math>D_i</math> is the concentration of the non-radiogenic isotope of the daughter element (assumed constant),~~

	~~:<math>P</math> is the initial concentration of the parent isotope~~, and

	~~:<math>\Delta{P}_t</math> is the total amount of the parent isotope which has decayed by time <math>t</math>~~.

	The ~~proof of (1) amounts to simple algebraic manipulation. It is useful~~ in ~~this form because it exhibits~~ the ~~relationship between quantities that actually exist at present~~. ~~To wit, <math>P-\Delta{P}_t</math>, <math>D+\Delta{P}_t</math> and <math>D_i</math> respectively correspond~~ to ~~the concentrations~~ of ~~parent, daughter~~ and ~~non-radiogenic isotopes found in the rock at the time~~ of ~~measurement~~.

	~~The ratios <math>D+\Delta{P}_t \over D_i</math> (relative concentration of daughter and non-radiogenic isotopes)~~ and <~~math~~>~~{ P-\Delta{P}_t \over D_i }~~<~~/math~~> ~~(relative concentration of parent and non-radiogenic isotope)~~ are ~~measured by [[mass spectrometry]] and plotted against each other in a three~~-isotope plot known as an ''isochron plot''. Ratios are used instead of absolute concentrations because mass spectrometers usually measure the former rather than the latter. (See particularly the section on [[Mass_spectrometry#Isotope_ratio_MS\|isotope ratio]] mass spectrometry.)

	~~If all data points lie on a straight line~~, ~~this line~~ is ~~called an isochron~~. ~~The better~~ the ~~fit of the data points~~ to ~~a line,~~ the ~~more reliable the resulting age estimate~~. ~~Since~~ the ~~ratio of the daughter and non-radiogenic isotopes~~ is ~~proportional~~ to ~~the ratio of the parent~~ and ~~non~~-~~radiogenic isotopes~~, the slope of the isochron gets steeper with time. The change in slope from initial conditions—assuming an initial isochron slope of zero (a horizontal isochron) at the point of intersection (intercept) of the isochron with the y-axis—to the current computed slope gives the age of the rock. ~~The slope of the isochron,~~ <~~math~~>~~\Delta{P}_t \over P-\Delta{P}_t~~<~~/math~~>~~, represents~~ the ~~ratio~~ of ~~daughter to parent as used in standard [[radiometric dating]]~~.

	~~Whole rock isochron dating uses the same ideas but instead~~ of ~~different minerals obtained from one rock uses different types~~ of ~~rocks~~ that ~~are derived from a common reservoir; e.g.~~ the ~~same precursor melt~~. It is ~~possible to date the differentiation~~ of the ~~precursor melt which then cooled and crystallized into~~ the ~~different types~~ of ~~rocks~~.

	~~One~~ of the ~~best known isotopic systems for isochron dating~~ is ~~the [[Rubidium-strontium dating\|rubidium-strontium]] system~~. ~~Other systems that are used~~ for ~~isochron dating include [[Samarium-neodymium dating\|samarium-neodymium]],~~ and ~~[[Uranium-lead dating\|uranium-lead]]~~. ~~Some isotopic systems based on short living extinct radionuclides such as~~ <~~span style="font-size:100%;"~~><~~sup~~>53</sup></span>[[manganese\|Mn]], <span style="font-size:100%;"><sup>26</sup></span>[[aluminum\|Al]], <span style="font-size:100%;"><sup>129</sup></span>[[iodine\|I]], <span style="font-size:100%;"><sup>60</sup></span>[[iron\|Fe]] and others are used for isochron dating of events in the early history of the [[solar system]]. However, methods using extinct radionuclides give only relative ages and ~~have to be calibrated with radiometric dating techniques based on long living radionuclides~~ like ~~Pb-Pb-dating~~ to ~~give absolute ages.~~

	~~==Application==~~
	Isochron dating is useful in the determination of the age of [[igneous rock]]s, which have their initial origin in the cooling of liquid [[magma]]. It is also useful to determine the time of metamorphism, shock events (such as the consequence of an [[asteroid]] impact) and other events depending of the behaviour of the particular isotopic systems under such events.

	~~==See also==~~
	*[[Radiometric dating]]

	~~==External links==~~
	*[http://www.~~geo.cornell.edu/geology/classes/Geo656/656notes05/656_05Lecture04.pdf Basics of radioactive isotope geochemistry from Cornell]~~
	*[http://www.talkorigins.~~org~~/~~faqs~~/~~isochron-dating.html Isochron Dating~~] at the ~~[[TalkOrigins Archive]]~~

	~~[[Category:Radiometric dating]]~~

en>JohnBlackburne: Reverted good faith edits by Pbierre (talk): No, that's the representation not the vector and not the only one. (TW)

2014-01-23T14:46:30Z

Reverted good faith edits by Pbierre (talk): No, that's the representation not the vector and not the only one. (TW)

← Older revision		Revision as of 16:46, 23 January 2014
Line 1:		Line 1:
	~~Understandably~~, ~~numerous anxiousness victims acquire clinical depression~~ as ~~properly~~, and ~~others~~ are ~~prone~~ to ~~produce alcohol~~ and ~~drug dependencies~~. ~~Sesame oil~~ is ~~great, but sunflower, coconut, or corn oil will work, too~~. ~~Involuntary facial tension is also~~ one of the ~~most emotionally debilitating symptoms because it severely restricts a person’s ability to convey even simple facial gestures~~, ~~such as smiling, that are critical to forming trust~~ with ~~other people~~. ~~You don't have~~ to ~~suffer from anxiety~~ - ~~cures are easier and faster than you might think~~. To some, ~~these new regulations may seem intrusive, but they were instilled with~~ the ~~best~~ of ~~intentions~~. ~~<br><br>Again~~, ~~there are~~ some ~~great resources online for you to look into and I hope you do~~. ~~And these therapy consequences are not dangerous by any means~~, ~~you're just loosing fat~~, ~~not loosing electrolytes~~. ~~Then make herself~~ a ~~cup~~ of the ~~calming tea~~, ~~and she felt back in control~~. ~~Come up with unique ways~~ to ~~help you overcome whatever personal problems~~. ~~People who suffer from depression cannot lead a normal life~~ and ~~maintaining relationships for them~~ is ~~not practically possible.~~ <br><br>~~Her goal as a Licensed Professional Counselor~~ is ~~to provide hope to clients for yesterday~~, ~~today~~, and the ~~future~~. The ~~more complex the condition, the more difficult it is~~ to ~~treat~~. ~~s likely~~ that ~~if you ask any two people with an anxiety disorder to describe it~~, ~~they''. If this has been happening~~ to ~~you lately~~, ~~you are likely having panic attacks. It is very important to have someone to talk to especially when there is something bothering on your mind to somehow ease~~ the ~~burden's that is inside you~~. <br><br>- ~~Mental~~ '~~muddiness~~' (~~inability~~ to ~~focus or concentrate)~~. ~~' Only those couple between~~ the ~~ages~~ of 30 and ~~50 may adopt kids. This~~ is ~~when you feel you have~~ to ~~do something again~~ and ~~again without any logical explanation just so you feel safe and secure~~. On the ~~net anxiety forums you'll notice a full variety~~ of ~~sections. Also, 'pushing'~~ the ~~energy can bring up what EFT founder, Gary Craig refers to as 'tail enders' which are~~ the ~~underlying limiting beliefs we have attached to~~ the ~~issue~~. <br><br>~~What should be important~~ to ~~you is not~~ the ~~type~~ of ~~anxiety you suffer~~ from ~~but how soon it can be cured~~. ~~We have reviewed e - Books, video programs, audio programs, music relaxation and natural herbal remedies and have found none come close to~~ the same ~~effictiveness of Panic Away~~. ~~Encourage your teen~~ to ~~approach~~ the ~~counter~~ and ~~order alone~~. ~~Before you hit the sheets at night, you should think about all~~ of the ~~great stuff that~~ is ~~occurring in your life right now~~. ~~When the victim gets to successfully relax~~, ~~his or her brain will no longer entertain any negative thoughts~~.<br><br>~~If you liked this article~~ and ~~you would~~ like to ~~acquire more info concerning~~ [http://www.~~stress-lavoro-correlato~~.~~info~~/~~sitemap~~/ ~~best medications for anxiety~~] ~~i implore you to visit our web page~~.		{{unreferenced\|date=January 2011}}
			'''Isochron dating''' is a common technique of [[radiometric dating]] and is applied to date certain events, such as [[crystal]]lization, [[metamorphism]], shock events, and differentiation of precursor melts, in the history of [[rock (geology)\|rocks]]. Isochron dating can be further separated into ''mineral isochron dating'' and ''whole rock isochron dating''; both techniques are applied frequently to date terrestrial and also extraterrestrial rocks ([[meteorite]]s). The advantage of isochron dating as compared to simple radiometric dating techniques is that no assumptions are needed about the initial amount of the daughter [[nuclide]] in the [[radioactive decay]] sequence. Indeed the initial amount of the daughter product can be determined using isochron dating. This technique can be applied if the daughter element has at least one stable [[isotope]] other than the daughter isotope into which the parent nuclide decays.

			==Basis for method==

			All forms of isochron dating assume that the source of the rock or rocks contained unknown amounts of both [[radiogenic]] and non-radiogenic isotopes of the daughter element, along with some amount of the parent nuclide. Thus, at the moment of crystallization, the ratio of the concentration of the radiogenic isotope of the daughter element to that of the non-radiogenic isotope is some value independent of the concentration of the parent. As time goes on, some amount of the parent decays into the radiogenic isotope of the daughter, increasing the ratio of the concentration of the radiogenic isotope to that of the daughter. The greater the initial concentration of the parent, the greater the concentration of the radiogenic daughter isotope will be at some particular time. Thus, the ratio of the daughter to non-radiogenic isotope will become larger with time, while the ratio of parent to daughter will become smaller. For rocks that start out with a small concentration of the parent, the daughter/non-radiogenic ratio will not change quickly as compared to rocks starting with a large concentration of the parent.

			==Isochron plots==

			To perform dating, a rock is crushed to a fine powder and minerals are separated by various physical and magnetic means. Each mineral has different ratios between parent and daughter concentrations. For each mineral, the ratios are related by the following equation:

			:<math>{ D+\Delta{P}_t \over D_i } =
			{\Delta{P}_t \over P-\Delta{P}_t } \left ( { P-\Delta{P}_t \over D_i }\right ) + {D \over D_i}</math>          (1)

			where

			:<math>D</math> is the initial concentration of the daughter isotope,

			:<math>D_i</math> is the concentration of the non-radiogenic isotope of the daughter element (assumed constant),

			:<math>P</math> is the initial concentration of the parent isotope, and

			:<math>\Delta{P}_t</math> is the total amount of the parent isotope which has decayed by time <math>t</math>.

			The proof of (1) amounts to simple algebraic manipulation. It is useful in this form because it exhibits the relationship between quantities that actually exist at present. To wit, <math>P-\Delta{P}_t</math>, <math>D+\Delta{P}_t</math> and <math>D_i</math> respectively correspond to the concentrations of parent, daughter and non-radiogenic isotopes found in the rock at the time of measurement.

			The ratios <math>D+\Delta{P}_t \over D_i</math> (relative concentration of daughter and non-radiogenic isotopes) and <math>{ P-\Delta{P}_t \over D_i }</math> (relative concentration of parent and non-radiogenic isotope) are measured by [[mass spectrometry]] and plotted against each other in a three-isotope plot known as an ''isochron plot''. Ratios are used instead of absolute concentrations because mass spectrometers usually measure the former rather than the latter. (See particularly the section on [[Mass_spectrometry#Isotope_ratio_MS\|isotope ratio]] mass spectrometry.)

			If all data points lie on a straight line, this line is called an isochron. The better the fit of the data points to a line, the more reliable the resulting age estimate. Since the ratio of the daughter and non-radiogenic isotopes is proportional to the ratio of the parent and non-radiogenic isotopes, the slope of the isochron gets steeper with time. The change in slope from initial conditions—assuming an initial isochron slope of zero (a horizontal isochron) at the point of intersection (intercept) of the isochron with the y-axis—to the current computed slope gives the age of the rock. The slope of the isochron, <math>\Delta{P}_t \over P-\Delta{P}_t</math>, represents the ratio of daughter to parent as used in standard [[radiometric dating]].

			Whole rock isochron dating uses the same ideas but instead of different minerals obtained from one rock uses different types of rocks that are derived from a common reservoir; e.g. the same precursor melt. It is possible to date the differentiation of the precursor melt which then cooled and crystallized into the different types of rocks.

			One of the best known isotopic systems for isochron dating is the [[Rubidium-strontium dating\|rubidium-strontium]] system. Other systems that are used for isochron dating include [[Samarium-neodymium dating\|samarium-neodymium]], and [[Uranium-lead dating\|uranium-lead]]. Some isotopic systems based on short living extinct radionuclides such as <span style="font-size:100%;"><sup>53</sup></span>[[manganese\|Mn]], <span style="font-size:100%;"><sup>26</sup></span>[[aluminum\|Al]], <span style="font-size:100%;"><sup>129</sup></span>[[iodine\|I]], <span style="font-size:100%;"><sup>60</sup></span>[[iron\|Fe]] and others are used for isochron dating of events in the early history of the [[solar system]]. However, methods using extinct radionuclides give only relative ages and have to be calibrated with radiometric dating techniques based on long living radionuclides like Pb-Pb-dating to give absolute ages.

			==Application==
			Isochron dating is useful in the determination of the age of [[igneous rock]]s, which have their initial origin in the cooling of liquid [[magma]]. It is also useful to determine the time of metamorphism, shock events (such as the consequence of an [[asteroid]] impact) and other events depending of the behaviour of the particular isotopic systems under such events.

			==See also==
			*[[Radiometric dating]]

			==External links==
			*[http://www.geo.cornell.edu/geology/classes/Geo656/656notes05/656_05Lecture04.pdf Basics of radioactive isotope geochemistry from Cornell]
			*[http://www.talkorigins.org/faqs/isochron-dating.html Isochron Dating] at the [[TalkOrigins Archive]]

			[[Category:Radiometric dating]]

en>Maschen: /* See also */ add Line element

2012-08-17T09:07:52Z