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At least 847 records · Page 47Linked to original sources
PubMed2004

Inclusive fitness for traits affecting metapopulation demography.

Defining computable analytical measures of the effects of selection in populations with demographic and environmental stochasticity is a long-standing problem. We derive an analytical measure which takes in account all consequences of the discrete nature of deme size. Expressions of this measure are detailed for infinite island models of population structure. As an illustration we consider the evolution of dispersal in populations made of small demes with environmental and demographic stochasticity. We confirm some results obtained from the analysis of models based on deterministic approximations. In particular, when there is an Allee effect, we show that evolution of the dispersal rate may lead the metapopulation to extinction. Thus, selection on the dispersal rate could restrict the distribution of species subject to Allee effects. This selection-driven extinction is prevented by kin selection when the environmental extinction rate is small.

Alleles↗
PubMed1998

QTL mapping of genotype-environment interaction for fitness in Drosophila melanogaster.

A fundamental assumption of models for the maintenance of genetic variation by environmental heterogeneity is that selection favours alternative alleles in different environments. It is not clear, however, whether such antagonistic pleiotropy is common. We mapped quantitative trait loci (QTLs) causing variation for reproductive performance in each of three environmental treatments among a set of 98 recombinant inbred (RI) lines derived from a cross between two D. melanogaster laboratory strains. The three treatments were standard medium at 25 degrees C, ethanol-supplemented medium at 25 degrees C, and standard medium at 18 degrees C. The RI lines showed highly significant genotype-environment interaction for the fitness measure. Of six QTLs with significant effects on fitness in at least one of the environments, five had significantly different effects at the different temperatures. In each case, the QTL by temperature interaction arose because the QTL had stronger effects at one temperature than at the other. No evidence for QTLs with opposite fitness effects in different environments was found. These results, together with those of recent studies of crop plants, suggest that antagonistic pleiotropy is a relatively uncommon form of genotype-environment interaction for fitness, but additional studies of natural populations are needed to confirm this conclusion.

Animals↗
PubMedDate not supplied

[Ecologo-hygienic evaluation of the use of petroleum-refining waste for road construction in the lower Volga region].

A scheme has been developed for sanitary assessment of the safety of road building materials containing oil slurry waste. It includes 2 units: 1) sanitary and chemical studies and 2) ecological and toxicological ones. The sanitary and chemical unit consists of a preliminary stage, wherein priority waste-specific substances are selected, and two experimental studies air- and water migration ones that evaluate the environmental effects of the substances selected. The ecological and toxicological unit includes microbiological, phytotoxic, hydrobiological, and toxicological studies. This scheme of ecological and sanitary studies of road building composite materials containing oil slurry waste allows their ecological and toxicological safety to be comprehensively evaluated.

Environmental Pollutants↗
PubMed1997

Environmental monitoring and banking of marine pollutants by using common mussels.

Since 1985 the common mussel Mytulis edulis has been collected, characterized and stored within the framework of the German Environmental Specimen Bank program. Selected results about the determination of various pollutants such as heavy metals, polycyclic aromatic hydrocarbons and chlorinated hydrocarbons are presented. Particular emphasis is given to the comparison of seasonal variations with respect to different environmental contaminants and their correlations depending on sampling location and time.

Animals↗
PubMed1988

Environmental variables differentially affect ethanol-stimulated activity in selectively bred mouse lines.

Low doses of ethanol (EtOH) stimulate activity in an open field in many strains of laboratory mice. We are selectively breeding two lines of mice to exhibit a large (FAST) response on this test, and two other lines to exhibit a small (SLOW) response (Crabbe et al. 1987). The lines initially diverged in response to EtOH, but despite continued selection pressure, the difference between each pair of FAST and SLOW lines has not increased over generations as much as expected. Our practice has been to test animals on the 1st day after saline injection, and repeat the test after EtOH injection 24 h later. Lister (1987) recently demonstrated that the order in which an animal was exposed to EtOH and saline influenced the magnitude of the response to EtOH, with animals tested initially after EtOH having greater stimulation. Middaugh et al. (1987) recently demonstrated that the magnitude of EtOH stimulation was greater under conditions of relatively bright light than under dim light. Using non-selected Swiss mice, the current experiments essentially confirmed Lister's findings. Using FAST and SLOW mice, the predictions of both groups were tested. Both hypotheses were confirmed. Additionally, these experiments demonstrated that the magnitude of the difference between FAST and SLOW mice was greater under bright light than under dim light. The line difference was also greater when tested in the EtOH-Saline order. In experiments with Swiss mice, the possible role of peritoneal irritation in the EtOH effect was eliminated, and the optimal dose and time for demonstrating the effect was determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Does the selection of ISO 14001 registrars matter? Registrar reputation and environmental policy statements in China.

This study investigates the relationship between characteristics of environmental policy statements and the reputations of ISO 14001 registrars who had performed certification audits of firms operating in mainland China. Three characteristics of environmental policy statements were examined: (1) The conformance of the policy to strict interpretations of the international standard; (2) The policy statement's adherence to the good practice guidelines specified in ISO 14004; and, (3) Self-reported evaluations of the policy statement's effectiveness as implemented. Data from 106 facilities in Beijing, Shanghai and Guangzhou reveal that registrar quality has a relatively weak, positive relationship with conformance to both ISO 14001 standards and to ISO 14004 guidelines, but no relationship was observed with the self-reported data. Additional findings are that the use of foreign registrars is significantly associated with the adoption of ISO 14004 guidelines and that conformance with ISO 14001 standards is somewhat higher for international joint ventures and foreign-owned firms than for state-owned enterprises.

Certification↗
PubMed2002

Dissociable effects of isolation rearing and environmental enrichment on exploration, spatial learning and HPA activity in adult rats.

Male Lister hooded rats were reared from weaning either singly or in groups of three in either barren or enriched cages (n=9 each) to study effects of isolation rearing and environmental enrichment on open-field activity, object exploration, activity in the Light/Dark box (L/D box), spatial learning and memory in the Morris water maze, and hypothalamic-pituitary-adrenal (HPA) activity in response to restraint stress. Regardless of inanimate background, isolation rearing mainly enhanced activity under several conditions of environmental novelty. By contrast, environmental enrichment, regardless of social background, primarily accelerated habituation to novelty and improved spatial learning and memory. None of the treatments significantly altered basal and response levels of plasma ACTH and corticosterone. Furthermore, rats reared singly in barren cages showed persistent activity in the L/D box, indicating an interaction between isolation-induced hyperactivity and reduced habituation due to barren caging. These results show that isolation rearing and environmental enrichment affect behaviour selectively, while at the same time revealing biologically relevant interactions between social and inanimate stimulation. It is concluded that systematic variation of social and inanimate stimulation can help distinguish between effects that generalise across variation in environmental background and effects that are idiosyncratic to a specific environmental background.

Adrenocorticotropic Hormone↗
PubMed2006

Selective attention, memory bias, and symptom perception in idiopathic environmental intolerance and somatoform disorders.

Idiopathic environmental intolerance (IEI) refers to a polysymptomatic condition, similar to somatoform disorders. Various processes seem to contribute to its yet unknown etiology. Attention and memory for somatic symptom and IEI-trigger words was compared among participants with IEI (n = 54), somatoform disorders (SFD; n = 44) and control participants (n = 54). Groups did not differ in a dot-probe task. However, in an emotional Stroop task, attention was biased in IEI and SFD groups toward symptom words but not toward IEI-trigger words. Only the IEI group rated trigger words as more unpleasant and more arousing, and participants remembered them better in a recognition task. These implicit and explicit cognitive abnormalities in IEI and SFD may maintain processes of somatosensory amplification.

Adolescent↗
PubMed1985

Effect of adding sodium taurocholate to selective media on the recovery of Clostridium difficile from environmental surfaces.

The recovery of Clostridium difficile on a medium containing cefoxitin, cycloserine, fructose, and egg yolk was compared with that on media containing one of three preparations of sodium taurocholate. In aerobic environments contaminated with C. difficile, media containing either crude taurocholate from Mann Research Laboratories, New York, N.Y., or pure taurocholate from Sigma Chemical Co., St. Louis, Mo., recovered organisms significantly more often than did cefoxitin-cycloserine-fructose-egg yolk agar.

Clostridium↗
PubMed2002

Environmental uncertainty and collaboration among California nonprofit hospitals.

Meeting the health needs of a community involves developing relationships with a wide range of partners. The purpose of this study was to determine the effect of environmental uncertainty on the level of interorganizational relations among nonprofit hospitals with the intent of providing community benefit. Findings indicate that nonprofit hospitals in California are collaborating to provide community benefit. Significant relationships were found between select hospital characteristics, perceived environmental uncertainty, and components of interorganizational relations.

California↗