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251.
Gerald S. Wilkinson 《Behavioral ecology and sociobiology》1985,17(2):111-121
Summary At a site in Costa Rica, three groups of 8–12 adult female vampire bats, Desmodus rotundus, utilize group-specific sets of hollow trees as day roosts. Long-term nonrandom associations between pairs of females, as measured by the proportion of time one bat spends roosting in the same tree with another bat over a 3 year period, occur even when preferences for particular trees are removed. Significant associations exist between both related and unrelated adult females. Adult male bats, however, show few associations with females or other males. By observing bats within trees and while foraging, and by monitoring feeding flights with radiotelemetry, the following potential benefits of association could be tested. Females roost together to (1) share a suitable microclimate, (2) avoid predators, (3) avoid ectoparasite infestations, (4) minimize travel to mobile prey animals, (5) respond to coercive males, (6) feed simultaneously from a bite, (7) remove ectoparasites by allogrooming, and (8) share food by regurgitating blood to other bats within roosts. The data do not indicate that any of the first five hypotheses provide significant benefits for long-term associations although predators and ectoparasite levels may cause occasional changes in roost sites. Simultaneous feeding was uncommon and apparently confined to females and their recent offspring. Allogrooming, although common, occurred independently of the presence of ectoparasites. Food sharing, however, occurred between both related and unrelated adult females with high levels of association and provides at least one selective advantage for maintaining cohesive female groups. 相似文献
252.
Several methods (cosolvents, surfactants, and cyclodextrins) were compared for improving desorption of a high explosive, RDX, from granular activated carbon (GAC). In batch desorption tests, 3% of the adsorbed RDX (initially 71.1 mg RDX/g GAC) was desorbed by water over 11 days, compared to 92.6% desorption by 100% ethanol. Solutions of ethanol or methanol in water also effectively desorbed RDX, although methanol was somewhat less effective than ethanol. Sodium dodecyl sulfate desorbed as much as 70% of the adsorbed RDX, while the non-ionic surfactants Tween 80, Triton X-100, and Brij 30 desorbed as much as 42 to 51% of the RDX. In continuous flow column tests, GAC was partially regenerated. One-half of the adsorbed RDX was desorbed by 2100 bed volumes (BV) of 10% ethanol, compared to the 22 500 BV of buffered water. Column modeling indicated that competitive adsorption and altered equilibrium conditions combined to enhance RDX desorption. 相似文献
253.
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255.
Gerald J. Kauffman Martha B. Corrozi Kevin J. Vonck 《Journal of the American Water Resources Association》2006,42(3):603-615
ABSTRACT: The New Castle County Resource Protection Area Technical Advisory Committee (RPATAC) requested that the University of Delaware utilize impervious cover estimates to evaluate the performance of the Water Resource Protection Area (WRPA) ordinance. This 1991 ordinance was the first in Delaware to protect the quantity and quality of drinking water supplies by limiting new development in WRPAs ‐ such as areas of ground water recharge, wellhead protection, drainage above reservoirs (reservoir watersheds), and limestone aquifers ‐ to a maximum 20 percent impervious cover. The research used geographic information system (GIS) techniques to evaluate the effectiveness of the ordinance in attaining its objective. The analysis indicated that 138 new developments were proposed in WRPAs since the ordinance was approved in 1991. The composite impervious cover of the 231 square kilometers of WRPAs in New Castle County is 15 percent, less than the 20 percent code requirement, ranging from 7 percent in recharge areas to 41 percent in several wellhead protection areas. To further protect drinking water supplies, the study results indicate, New Castle County should discourage code variances for applications in the more developed WRPAs, those where impervious cover already exceeds 20 percent, and should acquire parks and open space to protect the healthier WRPAs where impervious cover is currently less than 20 percent. 相似文献
256.
The present research examined the influence of negative affectivity (NA) on the form of the felt accountability–job tension relationship. It was hypothesized that the nonlinear relationship between felt accountability and job tension would surface only for individuals low in NA, whereas the association between these constructs would be positive and linear for individuals high in NA. Data from two studies (N = 198; N = 118) provided support for the hypothesis. These results have important implications for science and practice. Conceptually, this study contributes to the stress, accountability, and personality literatures by demonstrating that accountability can positively or negatively predict tension, and that this association is dependent upon affective disposition. Practically, managers need to be cognizant of the fact that increases in accountability are not always associated with favorable attitudes when managing employees. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
257.
Shui-Yan?Tang Pansy?Honying?Li Gerald?E.?Fryxell Carlos?Wing-Hung?LoEmail author 《Environmental management》2015,56(3):777-790
This study examines the effects of internal motivations and external pressures on the integration of environmental management (EM) practices within manufacturing operations in China. The moderating role of perceptions toward the regulatory process is also considered along with comparisons between wholly Chinese-owned and foreign-owned enterprises. From a sample of 131 manufacturing companies in the Guangzhou area, it was found that the salience of fees and fines has a strong positive influence on perceptions toward the regulator (the local Environmental Protection Bureau, EPB). This also has a positive effect on perceptions toward regulations themselves for foreign-owned enterprises. Business-case motivations for EM positively shape enterprise perceptions toward regulations, whereas risk-reduction motivations have a negative effect on perceptions toward regulations in foreign-owned enterprises. Enterprise perceptions toward the regulatory process have direct effects on the integration of EM practices in wholly Chinese-owned enterprises, but in opposite directions. While positive perceptions toward regulations have positive influence, positive perceptions toward regulators (i.e., the EPB) negatively affect it. Overall, these results indicated that promoting the adoption of EM practices depends on convincing business leaders that EM practices contribute to profit making. The regulatory process can potentially promote these practices, but measures need to be taken to ensure that the regulator is not co-opted by the regulated, especially in wholly Chinese-owned enterprises. 相似文献
258.
Gerald Taylor Aiken 《Local Environment》2015,20(7):764-781
This article addresses the narrowing interpretation of community when governmentalised: that of community's elision with local. First it surveys five broad academic and policy interpretations of the community implied in low carbon transitions. These demonstrate the persistence of community's broad and open-ended polysemy today. Second it looks more closely at the role community plays in UK environmental governance today, including specific evidence from two such government-funded community initiatives used to meet global environmental challenges: Transition Towns and Carbon Conversations. Third it provides a critique of community governance-beyond-the-state. It argues that community used to “jump scales” in response to global challenges like climate change, is often at its most narrow: local and governmentalised. Doing so helps contextualise the governmentalisation of (local-) community in UK environmental governance. Often it is localised in order to delegate (perceived) agency and responsibility onto individual actors at a local level. 相似文献
259.
Mayr G 《Die Naturwissenschaften》2007,94(8):681-685
Remains of fossil birds with numerous bony tubercles on the cervical vertebrae are reported from the Middle Eocene of Messel
in Germany and the Late Eocene of the Quercy fissure fillings in France. These structures, which are unknown from extant birds
and other vertebrates, were previously described for an avian skeleton from Messel but considered a singular feature of this
specimen. The new fossils are from a different species of uncertain phylogenetic affinities and show that tuberculated vertebrae
have a wider taxonomic, temporal, and geographic distribution. In contrast to previous assumptions, they are no ontogenetic
feature and arise from the vertebral surface. It is concluded that they are most likely of pathologic origin and the first
record of a Paleogene avian disease. Their regular and symmetrical arrangement over most of the external vertebral surface
indicates a systemic disorder caused by factors that do not affect extant birds, such as especially high-dosed phytohormones
or extinct pathogens. 相似文献
260.