نتایج جستجو برای: spatial variation

تعداد نتایج: 634391  

Journal: :Ecology 2007
Rose L Andrew Rod Peakall Ian R Wallis William J Foley

Exploring the spatial distribution of variation in plant secondary metabolites is critical for understanding the evolutionary ecology of biochemical diversity in wild organisms. In the present study, concentrations of foliar sideroxylonal, an important and highly heritable defense chemical of Eucalyptus melliodora, displayed strong, fine-scale spatial autocorrelation. The spatial patterns obser...

2012
Ji Luo Youchao Chen Yanhong Wu Peili Shi Jia She Peng Zhou

Soil respiration (SR) is an important process in the global carbon cycle. It is difficult to estimate SR emission accurately because of its temporal and spatial variability. Primary forest succession on Glacier forehead provides the ideal environment for examining the temporal-spatial variation and controlling factors of SR. However, relevant studies on SR are relatively scarce, and variations,...

ستوده, فاطمه, علیجانی, بهلول,

Precipitation is one of the important aspects of the Earth’s climate that has both spatial and temporal variations. Understanding the behavior of this element and analyzing its spatial and temporal variation is importantwhich can lead to a comprehensive and detailed planning for water resource management and agriculture. Geostatistical techniques and spatial autocorrelation analysis are t...

2015
Xiujuan Qiao Qianxi Li Qinghu Jiang Junmeng Lu Scott Franklin Zhiyao Tang Qinggang Wang Jiaxin Zhang Zhijun Lu Dachuan Bao Yili Guo Haibo Liu Yaozhan Xu Mingxi Jiang

Niche and neutral theories emphasize different processes contributing to the maintenance of species diversity. In this study, we calculated the local contribution to beta diversity (LCBD) of every cell, using variation partitioning in combination with spatial distance and environmental variables of the 25-ha Badagongshan plot (BDGS), to determine the contribution of environmentally-related vari...

2013
Ralf Vandam Eva Kaptijn Bram Vanschoenwinkel

The relative importance of deterministic and stochastic processes driving patterns of human settlement remains controversial. A main reason for this is that disentangling the drivers of distributions and geographic clustering at different spatial scales is not straightforward and powerful analytical toolboxes able to deal with this type of data are largely deficient. Here we use a multivariate ...

2011
Guifen Chen Wei Dong Jian Jiang Guowei Wang

Soil fertility is a comprehensive reflection of soil properties, and its variation has been a central issue in the field of soil science. Most of current research on Variation of the soil fertility are most for a single time and place, and using expertise, simple mathematical model approach that can not effectively simulate the temporal and spatial variation of soil nutrients law. Therefore, th...

Quality of life is multifaceted and relative concept. It is being affected by spatial and temporal variation as well as social – individual values. This bears different meaning for different groups. This study tries to measure quality of life based on subjective indices. It further identifies and analyses the major spatial factors responsible for life quality of the rural people. This study is ...

A.A Gholami GH.R Hadarbadi H Ebrahimi H Ghasemi

Of the many climatic events that influence the Earth’s environment, drought is perhaps the one that is most linked with desertification. Drought is the consequence of a natural reduction in the amount of precipitation received over an extended period, usually a season or more in length. Drought monitoring is an essential component of drought risk management. It is normally performed using vario...

Journal: :Physical review letters 2002
P M Singer A W Hunt T Imai

We report experimental evidence for the spatial variation of hole concentration x(hole) in the high T(c) superconductor La2-xSrxCuO4 ( 0.04 < or = x < or = 0.16) via 63Cu NQR using 63Cu isotope enriched samples. We demonstrate that the extent of the spatial variation of the local hole concentration Delta(x)hole is reflected on (63)1/T1 and deduce the temperature dependence. Delta(x)hole increas...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2002
David L Smith Brendan Lucey Lance A Waller James E Childs Leslie A Real

Often as an epidemic spreads, the leading front is irregular, reflecting spatial variation in local transmission rates. We developed a methodology for quantifying spatial variation in rates of disease spread across heterogeneous landscapes. Based on data for epidemic raccoon rabies in Connecticut, we developed a stochastic spatial model of rabies spread through the state's 169 townships. We qua...

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