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721.
Barrington-Leigh Christopher Behzadnejad Fatemeh 《Environmental Economics and Policy Studies》2017,19(2):269-298
Environmental Economics and Policy Studies - To estimate the impact of air pollution on well-being, we combine a set of repeated cross-sectional surveys of individuals with high-resolution... 相似文献
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Background level of risk determines the intensity of predator neophobia in juvenile convict cichlids
Grant E. Brown Douglas P. Chivers Chris K. Elvidge Christopher D. Jackson Maud C. O. Ferrari 《Behavioral ecology and sociobiology》2014,68(1):127-133
Behavioural ecology is rife with examples of prey animals that are able to adjust the intensity of their anti-predator response to match background risk levels. Often, preys need experience with predators before they will invest in costly anti-predator responses. This means that prey animals often fail to respond to predators during their first encounter. Recently, we have shown that prey raised under high-risk conditions may exhibit avoidance of potential predation cues independent of experience (neophobia). Such phenotypically plastic neophobic predator responses may reduce the initial costs of learning ecologically relevant threats while maintaining sufficient behavioural plasticity to respond to variation in local conditions. Here, we test if induced neophobia results in threat-sensitive behavioural trade-offs in response to a novel chemosensory cue. Our first experiment shows that while juvenile convict cichlids (Amatitlania nigrofasciata) pre-exposed to high (but not low) risk conditions exhibited predator avoidance to a novel odour (rainbow trout, Oncorhynchus mykiss), the response intensity was not influenced by the concentration of trout odour detected. Our second experiment demonstrated that the intensity of anti-predator response towards a novel predator cue was dependent upon the level of background risk. Convict cichlids pre-exposed to high-risk conditions showed stronger responses than those pre-exposed to low-risk conditions, while cichlids pre-exposed to intermediate-risk conditions exhibited intermediate response intensities. Together, these data demonstrate that background levels of risk and not the concentration of novel cues detected shape the induced neophobic response pattern of juvenile convict cichlids. 相似文献
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Robert D. Gibbons Jeremy W.F. Morris Christopher P. Prucha Michael D. Caldwell Bryan F. Staley 《Waste management (New York, N.Y.)》2014,34(9):1674-1682
Landfill functional stability provides a target that supports no environmental threat at the relevant point of exposure in the absence of active control systems. With respect to leachate management, this study investigates “gateway” indicators for functional stability in terms of the predictability of leachate characteristics, and thus potential threat to water quality posed by leachate emissions. Historical studies conducted on changes in municipal solid waste (MSW) leachate concentrations over time (longitudinal analysis) have concentrated on indicator compounds, primarily chemical oxygen demand (COD) and biochemical oxygen demand (BOD). However, validation of these studies using an expanded database and larger constituent sets has not been performed. This study evaluated leachate data using a mixed-effects regression model to determine the extent to which leachate constituent degradation can be predicted based on waste age or operational practices. The final dataset analyzed consisted of a total of 1402 samples from 101 MSW landfills. Results from the study indicated that all leachate constituents exhibit a decreasing trend with time in the post-closure period, with 16 of the 25 target analytes and aggregate classes exhibiting a statistically significant trend consistent with well-studied indicators such as BOD. Decreasing trends in BOD concentration after landfill closure can thus be considered representative of trends for many leachate constituents of concern. 相似文献
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Christopher R. Friesen Amelia R. Kerns Robert T. Mason 《Behavioral ecology and sociobiology》2014,68(9):1419-1430
In some species, sperm is stored within the female reproductive tract for months to years, and yet remains viable to fertilize eggs and produce offspring. Female red-sided garter snakes store sperm for over 7 months of winter dormancy. In previous work, we demonstrated that these stored sperm account for an average of 25 % paternity of a litter when the female mates with a male at spring emergence. Here, we tested whether last-male sperm precedence was prevalent when a female mates with two males during the spring. On average, paternity was shared equally among the first (P1 proportion of paternity of the first male to mate) and second males (P2) to mate in the spring, and stored sperm (Pss), but the variance in paternity was high. Thus, last male sperm precedence may diminish when a female has more than two mates. Male size did not affect paternity, but, as the interval between matings increased, P1 increased at the expense of Pss. Interestingly, as the second spring male’s copulation duration increased, P1 also increased at the expense of P2. This result suggests that female influence over sperm and/or copulatory plug transfer during matings may also affect which male fathers her offspring in response to coercive matings as we assisted females to mate for their second mating. Finally, all females were spring “virgins”; consequently, sperm stored from autumn matings (and/or previous spring matings) remain competitive even when faced with two rivals in sperm competition and is likely the driver of the evolution of sperm longevity. 相似文献
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Paul C. Kusnierz Christopher M. Holbrook David L. Feldman 《Environmental monitoring and assessment》2015,187(8):511
Managers of aquatic resources benefit from indices of habitat quality that are reproducible and easy to measure, demonstrate a link between habitat quality and biota health, and differ between human-impacted (i.e., managed) and reference (i.e., nonimpacted or minimally impacted) conditions. The instability index (ISI) is an easily measured index that describes the instability of a streambed by relating the tractive force of a stream at bankfull discharge to the median substrate size. Previous studies have linked ISI to biological condition but have been limited to comparisons of sites within a single stream or among a small number of streams. We tested ISI as an indicator of human impact to habitat and biota in mountain streams of the northwestern USA. Among 1428 sites in six northwestern states, ISI was correlated with other habitat measures (e.g., residual pool depth, percent fine sediment) and indices of biotic health (e.g., number of intolerant macroinvertebrate taxa, fine sediment biotic index) and differed between managed and reference sites across a range of stream types and ecoregions. While ISI could be useful in mountain streams throughout the world, this index may be of particular interest to aquatic resource managers in the northwestern USA where a large dataset, from which ISI can be calculated, exists. 相似文献
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Christopher Mayes 《Journal of Agricultural and Environmental Ethics》2014,27(2):265-286
This paper explores the influence and use of agrarian thought on collective understandings of food practices as sources of ethical and communal value in urban contexts. A primary proponent of agrarian thought that this paper engages is Paul Thompson and his exceptional book, The Agrarian Vision. Thompson aims to use agrarian ideals of agriculture and communal life to rethink current issues of sustainability and environmental ethics. However, Thompson perceives the current cultural mood as hostile to agrarian virtue. There are two related claims of this paper. The first argues that contrary to Thompson’s perception of hostility, agrarian thought is popularly and commercially mobilized among urban populations. To establish this claim I extend Charles Taylor’s notion of a social imaginary and suggest that urban agriculture can be theorized as an agrarian imaginary. Entwined with the first claim is the second, that proponents selectively use agrarian history to overemphasis a narrative of virtue while ignoring or marginalizing historical practices of agrarian violence, exclusion and dispossession. I do not discount or deny the significance of agrarian virtue. By situating agrarian thought within a clearer virtue ethics framework and acknowledging potential manifestation of agrarian vice, I suggest that the idea of agrarian virtue is strengthened. 相似文献