932 resultados para beauty in nature


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The natural environment and green spaces are settings that may facilitate physical activity and, as a result, combat childhood obesity and benefit children's physical health. A systematic review was conducted to assess the effect of children's engagement in outdoor activity on children's physical activity levels. A total of 169 articles were initially identified, of which 11 were eligible for inclusion in the systematic review. Studies were heterogeneous: cross-sectional, RCT, cohort, and direct observation. Study participants were between the ages of 3-15 years, and physical activity was measured by accelerometers, pedometers, direct observation or surveys. A majority of the studies (9/11) found a positive association between time spent outdoors and physical activity in children and adolescents. Of these 9 studies, 5 found this association specifically between time spent outdoors in greenspace and physical activity. Despite limitations, the findings of this review support the positive association between time spent outdoors and physical activity in children and adolescents, and the notion that children and adolescents who spend more time outdoors are more physically active. This demonstrates the need to use outdoor environments as settings for children's and adolescents' physical activity.^

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Predicting the impacts of ocean acidification on coastal ecosystems requires an understanding of the effects on macroalgae and their grazers, as these underpin the ecology of rocky shores. Whilst calcified coralline algae (Rhodophyta) appear to be especially vulnerable to ocean acidification, there is a lack of information concerning calcified brown algae (Phaeophyta), which are not obligate calcifiers but are still important producers of calcium carbonate and organic matter in shallow coastal waters. Here, we compare ecological shifts in subtidal rocky shore systems along CO2 gradients created by volcanic seeps in the Mediterranean and Papua New Guinea, focussing on abundant macroalgae and grazing sea urchins. In both the temperate and tropical systems the abundances of grazing sea urchins declined dramatically along CO2 gradients. Temperate and tropical species of the calcifying macroalgal genus Padina (Dictyoaceae, Phaeophyta) showed reductions in CaCO3 content with CO2 enrichment. In contrast to other studies of calcified macroalgae, however, we observed an increase in the abundance of Padina spp. in acidified conditions. Reduced sea urchin grazing pressure and significant increases in photosynthetic rates may explain the unexpected success of decalcified Padina spp. at elevated levels of CO2. This is the first study to provide a comparison of ecological changes along CO2 gradients between temperate and tropical rocky shores. The similarities we found in the responses of Padina spp. and sea urchin abundance at several vent systems increases confidence in predictions of the ecological impacts of ocean acidification over a large geographical range.

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Cannibalism is widespread in natural populations of fishes, where the stomachs of adults frequently contain conspecific juveniles. Furthermore, field observations suggest that guardian males routinely eat offspring from their own nests. However, recent genetic paternity analyses have shown that fish nests often contain embryos not sired by the nest-tending male (because of cuckoldry events, egg thievery, or nest piracy). Such findings, coupled with the fact that several fish species have known capabilities for distinguishing kin from nonkin, raise the possibility that cannibalism by guardian males is directed primarily or exclusively toward unrelated embryos in their nests. Here, we test this hypothesis by collecting freshly cannibalized embryos from the stomachs of several nest-tending darter and sunfish males in nature and determining their genetic parentage by using polymorphic microsatellite markers. Our molecular results clearly indicate that guardian males do indeed consume their own genetic offspring, even when unrelated (foster) embryos are present within the nest. These data provide genetic documentation of filial cannibalism in nature. Furthermore, they suggest that the phenomenon may result, at least in part, from an inability of guardians to differentiate between kin and nonkin within their own nests.

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Previous research has shown that amphibians have differential sensitivity to ultraviolet-B (UV-B) radiation. In some species, ambient levels of UV-B radiation cause embryonic mortality in nature. The detrimental effects of UV-B alone or with other agents may ultimately affect amphibians at the population level. Here, we experimentally demonstrate a synergistic effect between UV-B radiation and a pathogenic fungus in the field that increases the mortality of amphibian embryos compared with either factor alone. Studies investigating single factors for causes of amphibian egg mortality or population declines may not reveal the complex factors involved in declines.

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Mode of access: Internet.

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Mode of access: Internet.

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v. 1 Epicosmology.--v. 2. Outlines of ontology. Eternal forces, laws, and principles.--v. 3. Outlines of biology. Body, soul, mind, spirit.--v. 4. Collective biology and sociology.

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Frontispiece and 10 plates are mounted India proofs of etchings.

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Illustrations consist of color chips.

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Mode of access: Internet.