نتایج جستجو برای: ecological groups

تعداد نتایج: 822297  

Journal: :J. Informetrics 2013
Ludo Waltman Nees Jan van Eck

We address the question how citation-based bibliometric indicators can best be normalized to ensure fair comparisons between publications from different scientific fields and different years. In a systematic large-scale empirical analysis, we compare a traditional normalization approach based on a field classification system with three source normalization approaches. We pay special attention t...

Journal: :Marine pollution bulletin 2009
J C Marques A Basset T Brey M Elliott

The ability to achieve ecological sustainability and the sustainable development of marine and estuarine ecosystems constitutes a complex major challenge and depends on many driving forces, often conflicting with each other. In particular, there are three major drivers: (a) the search for human well-being, health and safety, (b) the maintenance of ecological sustainability and environmental equ...

Journal: :J. Symb. Log. 2003
Tomek Bartoszynski Saharon Shelah Boaz Tsaban

In a work of Just, Miller, Scheepers and Szeptycki it was asked whether certain diagonalization properties for sequences of open covers are provably closed under taking finite or countable unions. In a recent work, Scheepers proved that one of the properties in question is closed under taking countable unions. After surveying the known results, we show that none of the remaining classes is prov...

رحیمی, وریا, عادل, محمد نقی, پوربابائی, حسن,

The aim of this study was to investigate the relationship between physical and chemical properties of soils with vegetation distribution in Divan-Darre rangeland as one of the most important rangelands in Kurdistan province. For this purpose, a random systematic 150 m × 200 m gird sampling plan was used to establish 90 sampling plots. In each plot, soil factors and percent cover of each plant s...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده علوم 1375

the thesis has been arranged into five chapters and mainly concerned with the baer-invariant of groups which is the generalization of the schur-multiplier with respect to the variety of groups. chapter one is devoted to collect some notation and background information which are needed in the next chapters. its also contains some important statements which will be generalized in this thesis. cha...

2014
Bridget Freisthler Sharon Lipperman-Kreda Melina Bersamin Paul J. Gruenewald

Prevention researchers have found that drinking in different contexts is related to different alcohol problems. Where and with whom people drink affects the types of alcohol-related problems they experience. Consequently, identifying those contexts that result in the greatest number of problems provides a novel opportunity to target new prevention efforts aimed at those contexts. However, ident...

Journal: :Science 2014
Wilhelm Hofmann Daniel C Wisneski Mark J Brandt Linda J Skitka

The science of morality has drawn heavily on well-controlled but artificial laboratory settings. To study everyday morality, we repeatedly assessed moral or immoral acts and experiences in a large (N = 1252) sample using ecological momentary assessment. Moral experiences were surprisingly frequent and manifold. Liberals and conservatives emphasized somewhat different moral dimensions. Religious...

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