نتایج جستجو برای: fitness factor
تعداد نتایج: 893732 فیلتر نتایج به سال:
A class of variable fitness Genetic Algorithms is studied as a technique for use on constrained optimization problems. Fitness is taken as the product of the objective with an “attenuation” factor which is 1 for feasible solutions but some variable fraction of 1 for infeasible ones. It is shown that this technique leads to algorithms which converge in probability to globally optimal, feasible s...
Adaptation to climate, evolving over contemporary time scales, could facilitate rapid range expansion across environmental gradients. Here, we examine local adaptation along a climatic gradient in the North American invasive plant Lythrum salicaria. We show that the evolution of earlier flowering is adaptive at the northern invasion front where it increases fitness as much as, or more than, the...
It is widely believed that the slowest dispersal strategy is selected in the evolutional if the environment is temporally invariant but spatially heterogeneous. Authors claim in this paper that this belief is true only if random dispersals with constant motility are considered. However, if a dispersal strategy with fitness property is included, the size of the dispersal is not such a crucial fa...
Fluoroquinolones (FQ) are the recommended antimicrobial treatment for typhoid, a severe systemic infection caused by the bacterium Salmonella enterica serovar Typhi. FQ-resistance mutations in S. Typhi have become common, hindering treatment and control efforts. Using in vitro competition experiments, we assayed the fitness of eleven isogenic S. Typhi strains with resistance mutations in the FQ...
Background & aim: Background & aim: Physical fitness is essential for maintaining optimal health and can be achieved and improved by doing physical activities. Maximal oxygen consumption (VO2 max) has been used as a measure of physical fitness. This study aimed to determine the effect of jogging program on midwives' physical fitness. Methods:In this randomized controlled trial two large healthc...
Physical exercise is proposed as a highly effective means of treating and preventing the main causes of morbidity and mortality--most of which are associated with aging--in industrialized countries. Low physical fitness is an important risk factor for cardiovascular and all-causes morbidity and mortality; indeed, it is even a predictor of these problems. When properly measured, the assessment o...
Classical evolutionary theory predicts the existence of genes with antagonistic effects on longevity and various components of early-life fitness. Quantitative genetic studies have provided convincing evidence that such genes exist. However, antagonistic pleiotropic effects have rarely been attributed to individual loci. We examine several classes of longevity-assurance genes: those involved in...
Firefighting is a hazardous and physically demanding activity. The demanding nature of the tasks involved in firefighting requires a high level of fitness both for the safety of the firefighting personnel as well as for the adequate performance of their tasks. Here, the characteristics (body weight, lung function, etc.) of a small group of refinery firefighters were investigated using explorato...
The emergence of multi- and extensively drug-resistant tuberculosis (MDR-TB and XDR-TB, respectively) has intensified the critical public health implications of this global disease. The fitness of Mycobacterium tuberculosis (M.tb.) strains exhibiting MDR and XDR phenotypes is of fundamental importance in predicting whether the MDR-/XDR-TB epidemic will be sustained across the human population. ...
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