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101.
Summary. Although terrestrial turtles have served as a model for studies of olfactory neurophysiology, little is known about how they use chemical information in an ecological sense. We tested whether box turtles (Terrapene carolina) use chemical information to distinguish between predatory and nonpredatory mammals. Box turtles in our study exhibited more escape behavior when exposed to urine from a predator (coyote, Canis latrans) than when exposed to urine from a nonpredator (white-tailed deer, Odocoileus virginianus) or a blank control. Escape behavior is consistent with an antipredator response. In addition, the turtles decreased their handling time for food when in the presence of urine from either species of mammal in comparison to the blank, indicating that chemical cues from mammals in general may result in increased vigilance by terrestrial turtles. Examination of a variety of response variables may be important for adequate assessment of the ecological role of chemosensory behavior.  相似文献   
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Grout formulations have been investigated in Nevada Nuclear Waste Storage Investigations Project, for possible nuclear waste repository sealing applications focused in the Yucca Mountain Area (in welded tuff). A shrinkage compensated cement was chemically modified with siliceous reactants to enhance the chemical compatibility with a siliceous tuff. Fluids in contact with the grouts were measured at 150 °C and 200 °C, and the solids were characterized. Well-crystallized Al-substituted tobermorite and truscottite were observed, and sometimes xonotlite as dominant cementitious phases. Comparisons of solid phases and solution phases are made with a second grout incorporating siliceous modifiers in a Class H cement. Exposures to 150 °C hydrothermal conditions have not produced significant detrimental mechanical behavior of the seal material. The thermal decomposition of ettringite, an expansive calcium sulfate aluminate hydrate, resulted in a small increase in the porosity of the grout, but on a very small fine scale.  相似文献   
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In this paper we estimate a flexible form cost function of the aluminium industry in the USA and use our estimates to obtain derived demand curves for aluminium inputs such as electricity and bauxite. We then calculate the welfare gains arising from decreased energy use when the level of secondary recycling is increased. The process is repeated for several model specifications. All of our tests, however, yield similar results and indicate that substitution of scrap for only 5% of the bauxite presently used in US aluminium manufacturing would result in annual savings of close to a quarter of a billion dollars.  相似文献   
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Chromium-induced membrane damage: protective role of ascorbic acid   总被引:1,自引:0,他引:1  
IntroductionThechromiumplaysdualroleinnature .Thechromium (Ⅲ )isessentialforglucoseandlipidmetabolism(Chorvatovicova ,1993) .Ontheotherhand ,excessiveintakeofchromium (Ⅵ )compoundsarepotenttoxicandcarcinogenictothebody (DeFlora ,1990 ) .Hepaticandrenaltoxicityisthemo…  相似文献   
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