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Even Tjørve 《Journal of Biogeography》2009,36(8):1435-1445
This paper has extended and updated my earlier list and analysis of candidate models used in theoretical modelling and empirical examination of species–area relationships (SARs). I have also reviewed trivariate models that can be applied to include a second independent variable (in addition to area) and discussed extensively the justifications for fitting curves to SARs and the choice of model. There is also a summary of the characteristics of several new candidate models, especially extended power models, logarithmic models and parameterizations of the negative-exponential family and the logistic family. I have, moreover, examined the characteristics and shapes of trivariate linear, logarithmic and power models, including combination variables and interaction terms. The choice of models according to best fit may conflict with problems of non-normality or heteroscedasticity. The need to compare parameter estimates between data sets should also affect model choice. With few data points and large scatter, models with few parameters are often preferable. With narrow-scale windows, even inflexible models such as the power model and the logarithmic model may produce good fits, whereas with wider-scale windows where inflexible models do not fit well, more flexible models such as the second persistence (P2) model and the cumulative Weibull distribution may be preferable. When extrapolations and expected shapes are important, one should consider models with expected shapes, e.g. the power model for sample area curves and the P2 model for isolate curves. The choice of trivariate models poses special challenges, which one can more effectively evaluate by inspecting graphical plots. 相似文献
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Olav Hungnes Knut Jønsrud Enok Tjøtta Bjørn Grinde 《Journal of molecular evolution》1993,37(2):198-203
The large number of sequenced clones of HIV-1 and related viruses made it possible to indicate conserved elements with potential
regulatory or structural functions. Such analysis was combined with directed mutagenesis in order to investigate the importance
of elements that may influence the initiation of plus-strand DNA synthesis. The main site for plus-strand initiation is a
polypurine tract near the 3′ end of the viral RNA (the 3′ PPT). An exact copy of this PPT is located in the middle of the
genome (the internal PPT). Upstream from the internal PPT there is an inverted repeat. Mutants designed to upset the internal
PPT (i.e., purine to pyrimidine changes), as well as mutants designed to abolish the potential stem-loop formation (changes
around the internal PPT or in the upstream inverted repeat) both resulted in viruses with a reduced ability to replicate.
Upsetting the stem-loop formation was, however, less harmful than changing the polypurine nature of the PPT. Changing a conserved
T on the 3′ side of the PPT to a C did not affect the phenotype.
Presented at the NATO Advanced Research Workshop onGenome Organization and Evolution, Spetsai, Greece, 16–22 September 1992 相似文献
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P. Denys A. Even Schneider J. M. Soler D. Ben Smail E. Chartier-Kastler 《Andrologie》2001,11(4):240-242
The majority of spinal cord injured males cannot procreate naturally due to anejaculation as well as abnormal sperm characteristics. Treatment of this impaired fertility must be associated with treatment of neurogenic urinary tract disorders, bowel dysfunction and spasticity. The level of the spinal lesion and the spinal cord injury syndrome influence the possibility of inducing reflex ejaculation by penile vibratory stimulation and sperm quality. 相似文献
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History and Philosophy of the Life Sciences - This is an introduction to the topical collection Microbes, Networks, Knowledge: Disease Ecology in the twentieth Century, based on a workshop held at... 相似文献
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Stina K. Lien Håvard Sletta Trond E. Ellingsen Svein Valla Elon Correa Royston Goodacre Kai Vernstad Sven Even Finborud Borgos Per Bruheim 《Metabolomics : Official journal of the Metabolomic Society》2013,9(2):403-417
Metabolic profiling of Pseudomonas fluorescens SBW25 and various mutants derived thereof was performed to explore how the bacterium adapt to changes in carbon source and upon induction of alginate synthesis. The experiments were performed at steady-state conditions in nitrogen-limited chemostats using either fructose or glycerol as carbon source. Carbon source consumption was up-regulated in the alginate producing mutant with inactivated anti-sigma factor MucA. The mucA- mutants (also non-alginate producing mucA- control strains) had a higher dry weight yield on carbon source implying a change in carbon and energy metabolism due to the inactivation of the anti-sigma factor MucA. Both LC–MS/MS and GC–MS methods were used for quantitative metabolic profiling, and major reorganization of primary metabolite pools in both an alginate producing and a carbon source dependent manner was observed. Generally, larger changes were observed among the phosphorylated glycolytic metabolites, the pentose phosphate pathway metabolites and the nucleotide pool than among amino acids and citric acid cycle compounds. The most significant observation at the metabolite level was the significantly reduced energy charge of the mucA- mutants (both alginate producing and non-producing control strains) compared to the wild type strain. This reduction was caused more by a strong increase in the AMP pool than changes in the ATP and ADP pools. The alginate-producing mucA- mutant had a slightly increased GTP pool, while the GDP and GMP pools were strongly increased compared to non-producing mucA- strains and to the wild type. Thus, whilst changes in the adenosine phosphate nucleotide pool are attributed to the mucA inactivation, adjustments in the guanosine phosphate nucleotide pool are consequences of the GTP-dependent alginate production induced by the mucA inactivation. This metabolic profiling study provides new insight into carbon and energy metabolism of the alginate producer P. fluorescens. 相似文献
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Anne-Marie Lundsgaard Jacob B. Holm Kim A. Sjøberg Kirstine N. Bojsen-Møller Lene S. Myrmel Even Fjære Benjamin A.H. Jensen Trine S. Nicolaisen Janne R. Hingst Sine L. Hansen Sophia Doll Philip E. Geyer Atul S. Deshmukh Jens J. Holst Lise Madsen Karsten Kristiansen Jørgen F.P. Wojtaszewski Erik A. Richter Bente Kiens 《Cell metabolism》2019,29(1):50-63.e4
10.
Andersen Julie Høgsgaard Tjørnhøj-Thomsen Tine Reventlow Susanne Davidsen Annette Sofie 《Culture, medicine and psychiatry》2019,43(3):425-441
Culture, Medicine, and Psychiatry - An increasing number of young adults in Denmark experience difficulties in completing their education and holding down a job. Many of these young adults have... 相似文献