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931.
932.
933.
Environment as the Stage for Economic Actors 总被引:6,自引:0,他引:6
John E Coulter Shi Lei Samantha Jenkins 《中国人口.资源与环境(英文版)》2007,5(1):3-8
The relative importance of economics and environment in debate may soon be reversed due to the influence of three fac- tors. Firstly, in the global economy it is hard to hide the unwanted products of economic processes. Secondly, huge advances in sci- ence will reduce the imperfect knowledge of markets, making some monitoring and analyzing tools show the design of sensible and equitable livelihood in communities, which is more important than the motivation of maximising profits for some individuals or firms. Thirdly, China, as the last major player on the planet to take on economic growth, comes from traditions fundamentally differ- ent from those economies that have experienced the Industrial Revolution previously. Its challenges with sustainability and en- vironmental conservation predate Western economics by millennia, and it is implementing policies domestically and starting to work on the world stage that acknowledges that the surroundings are the host for any economic and socio-political system. 相似文献
934.
State-specific detection probabilities and disease prevalence. 总被引:2,自引:0,他引:2
Christopher S Jennelle Evan G Cooch Michael J Conroy Juan Carlos Senar 《Ecological applications》2007,17(1):154-167
Investigations of disease dynamics in wild animal populations often use estimated prevalence or incidence as a measure of true disease frequency. Such indices, almost always based solely on raw counts of infected and uninfected individuals, are often used as the basis for analysis of temporal and spatial dynamics of diseases. Generally, such studies do not account for potential differences in observer detection probabilities of host individuals stratified by biotic and/or abiotic factors. We demonstrate the potential effects of heterogeneity in state-specific detection probabilities on estimated disease prevalence using mark-recapture data from previous work in a House Finch (Carpodacus mexicanus) and Mycoplasma gallisepticum system. In this system, detection probabilities of uninfected finches were generally higher than infected individuals. We show that the magnitude and seasonal pattern of variation in estimated prevalence, corrected for differences in detection probabilities, differed markedly from uncorrected (apparent) prevalence. When the detection probability of uninfected individuals is higher than infected individuals (as in our study), apparent prevalence is negatively biased, and vice versa. In situations where state-specific detection probabilities strongly interact over time, we show that the magnitude and pattern of apparent prevalence can change dramatically; in such cases, observed variations in prevalence may be completely spurious artifacts of variation in detection probability, rather than changes in underlying disease dynamics. Accounting for differential detection probabilities in estimates of disease frequency removes a potentially confounding factor in studies seeking to identify biotic and/or abiotic drivers of disease dynamics. Given that detection probabilities of different groups of individuals are likely to change temporally and spatially in most field studies, our results underscore the importance of estimating and incorporating detection probabilities in estimated disease prevalence (specifically), and more generally, any ecological index used to estimate some parameter of interest. While a mark-recapture approach makes it possible to estimate detection probabilities, it is not always practical, especially at large scales. We discuss several alternative approaches and categorize the assumptions under which analysis of uncorrected prevalence may be acceptable. 相似文献
935.
The important role that non-motorised transport plays in urban sustainability is discussed with particular reference to the developing world and to the links between environmental and poverty issues. The significance of non-motorised transport in terms of reduced pollution, income maintenance for the poor and providing transport for vulnerable groups is stressed and placed within the general context of sustainable development. More specifically, evidence is presented for rickshaws in Calcutta, which demonstrates the vital role that non-motorised transport must play if sustainable development objectives are to be met. This evidence indicates that if rickshaws were to disappear from Calcutta's streets there would not only be significant increases in air pollution but also a substantial increase in the numbers of people living in poverty. 相似文献
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938.
We used genotypic data from three highly polymorphic microsatellite loci (two autosomal and one sex-linked) to examine micro-spatial
and temporal arrangements of genetic paternity for more than 1,500 embryos housed along 12 egg-case strings of the knobbed
whelk, Busycon carica. Multiple paternity proved to be the norm in these single-dam families, with genetic contributions of several sires (at least
3.5 on average) being represented among embryos within individual egg capsules as well as along the string. Two strings were
studied in much greater detail; five and seven fathers were identified, none of which was among the several males found in
consort with the female at her time of egg-laying. Each deduced sire had fathered roughly constant proportions of embryos
along most of the string, but those proportions differed consistently among fathers. A few significant paternity shifts at
specifiable positions along an egg-case string were also observed. Although the precise physical mechanisms inside a female
whelk’s reproductive tract remain unknown, our genetic findings indicate that successive fertilization events (and/or depositions
of zygotes into egg capsules) normally occur as near-random draws from a well-but-not-perfectly blended pool of gametes (or
zygotes) stemming from stored ejaculates, perhaps in different titers, of a dam’s several mates. 相似文献
939.
940.