翻訳と辞書 Words near each other ・ Relative contact homology ・ Relative currency strength ・ Relative dating ・ Relative Dementias ・ Relative density ・ Relative dentin abrasivity ・ Relative deprivation ・ Relative deprivation thesis ・ Relative dimension ・ Relative Dimensions ・ Relative direction ・ Relative effectiveness factor ・ Relative Fear ・ Relative fluorescence units ・ Relative gain (international relations) ・ Relative growth rate ・ Relative Heroes ・ Relative homology ・ Relative humidity ・ Relative identifier ・ Relative income hypothesis ・ Relative index of inequality ・ Relative Insight ・ Relative intensity noise ・ Relative interior ・ Relative key ・ Relative locality ・ Relative luminance ・ Relative market share ・ Relative Merits Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Relative growth rate ： ウィキペディア英語版 Relative growth rate Relative growth rate (RGR) is the growth rate relative to the size of the population. It is also called the exponential growth rate, or the continuous growth rate. In terms of differential equations, if $P$ is the population, and $\backslash frac$ its growth rate, then its relative growth rate is $\backslash frac\backslash frac$. If the relative growth rate is constant, i.e., $\backslash frac\backslash frac\; =\; k$, it is not difficult to verify that the solution to this equation is $P(t)\; =\; \backslash exp(kt)$. When calculating or discussing relative growth rate, it is important to pay attention to the units of time being considered. For example, if an initial population of $P\_0$ bacteria doubles every twenty minutes, then at time $t$ it is given by the equation $P(t)\; =\; P\_0\; 2^t\; =\; P\_0\; \backslash exp(\backslash ln(2)t)$ where $t$ is the number of twenty-minute intervals that have passed. However, we usually prefer to measure time in hours or minutes, and it is not difficult to change the units of time. For example, since 1 hour is 3, twenty-minute intervals, the population in one hour is $P(3)=P\_0\; 2^3$. The hourly growth factor is 8, which means that for every 1 at the beginning of the hour, there are 8 by the end. Indeed, $P(T)\; =\; P\_0\; 8^T\; =\; P\_0\; \backslash exp(\backslash ln(8)T)$ where $T$ is measured in hours, and the relative growth rate may be expressed as $\backslash ln(2)$ or approximately 69% per twenty minutes, and as $\backslash ln(8)$ or approximately 208% per hour.〔 In plant physiology, RGR is a measure used to quantify the speed of plant growth. It is measured as the mass increase per aboveground biomass per day, for example as g g−1 d−1. It is considered to be the most widely used way of estimating plant growth, but has been criticised as calculations typically involve the destructive harvest of plants. Another problem is that RGR nearly always decreases over time as the biomass of a plant increases, but traditionally this has been ignored when modelling plant growth. The RGR decreases for several reasons - non-photosynthetic biomass (roots and stems) increases, the top leaves of a plant begin to shade lower leaves and soil nutrients can become limiting. Overall, respiration scales with total biomass, but photosynthesis only scales with photosynthetic biomass and as a result biomass accumulates more slowly as total biomass increases. The RGR of trees in particular slow with increasing size due in part to the large allocation to structural material of the trunk required to hold photosynthetic material up in the canopy. A novel approach to separate size effects from intrinsic growth differences is implemented and described in detail in Philipson ''et al.'' (2012).〔Christopher D. Philipson, Philippe Saner, Toby R. Marthews, Reuben Nilus, Glen Reynolds, Lindsay A. Turnbull, Andy Hector (2012) Light-based regeneration niches: evidence from 21 dipterocarp species using size-specific RGRs. Biotropica. doi:10.1111/j.1744-7429.2011.00833.x http://onlinelibrary.wiley.com/doi/10.1111/j.1744-7429.2011.00833.x/abstract;jsessionid=49E8727AE3DD4F0E2A0BD887E972B84F.d03t03〕 RGR is calculated using the following equation:〔 $RGR\; =\; (\backslash ln\; W\_2\; -\; \backslash ln\; W\_1)/(t\_2-t\_1)$ Where: $\backslash ln$ = natural logarithm $t\_1$ = time one (in days) $t\_2$ = time two (in days) $W\_1$ = Dry weight of plant at time one (in grams) $W\_2$ = Dry weight of plant at time two (in grams) ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Relative growth rate」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.