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271.
Simon Coghlan 《Journal of Agricultural and Environmental Ethics》2018,31(3):349-367
This essay examines the fundamental role of veterinarians in companion animal practice by developing the idea of veterinarians as strong advocates for their nonhuman animal patients. While the practitioner-patient relationship has been explored extensively in medical ethics, the relation between practitioner and animal patient has received relatively less attention in the expanding but still young field of veterinary ethics. Over recent decades, social and professional ethical perspectives on human-animal relationships have undergone major change. Today, the essential role of veterinarians is not entirely clear. Furthermore, veterinarians routinely face pressure, often insidious, to refrain from pursuing their patients’ vital interests. In exploring the concept of strong patient advocacy, this essay investigates the increasingly common suggestion that veterinarians have ‘primary obligation’ and ‘first allegiance’ to their animal patients rather than to other parties, such as their clients or employers. The related concept of a fiduciary duty, which is sometimes encountered in medical ethics, is similarly explored as it applies to companion animal practice. The resultant idea of a strong patient advocate places companion animal veterinarians conceptually and ethically close to human health professionals, not least pediatricians. 相似文献
272.
Edward?A.?RoualdesEmail authorView authors OrcID profile
return OK on get Simon?J.?Bonner Thomas?D.?Whitney James?D.?Harwood 《Environmental and Ecological Statistics》2016,23(2):317-336
The literature on modelling a predator’s prey selection describes many intuitive indices, few of which have both reasonable statistical justification and tractable asymptotic properties. Here, we provide a simple model that meets both of these criteria, while extending previous work to include an array of data from multiple species and time points. Further, we apply the expectation–maximisation algorithm to compute estimates if exact counts of the number of prey species eaten in a particular time period are not observed. We conduct a simulation study to demonstrate the accuracy of our method, and illustrate the utility of the approach for field analysis of predation using a real data set, collected on wolf spiders using molecular gut-content analysis. 相似文献
273.
Simon McCarthy Sylvia Tunstall Dennis Parker Hazel Faulkner Joe Howe 《Environmental Hazards》2013,12(3):179-192
Risk communication in flood incident management can be improved through developing hydrometeorological and engineering models used as tools for communicating risk between scientists and emergency management professionals. A range of such models and tools was evaluated by participating flood emergency managers during a 4-day, real-time simulation of an extreme event in the Thamesmead area in the Thames estuary close to London, England. Emergency managers have different communication needs and value new tools differently, but the indications are that a range of new tools could be beneficial in flood incident management. Provided they are communicated large model uncertainties are not necessarily unwelcome among flood emergency managers. Even so they are cautious about sharing the ownership of weather and flood modelling uncertainties. 相似文献
274.
Alla L. Alpatova Melissa J. Baumann Simon H. Davies Susan J. Masten 《Environmental Chemistry Letters》2013,11(3):309-313
This article reports for the first time that fullerene (nC60) can form chlorinated disinfection by-products in aqueous systems at ambient temperature. The ability of nC60 to form colloidal suspensions in aqueous media increases the chance that these particles will migrate in the environment and then in drinking water supply systems. Since nC60 is not completely removed by conventional water treatment, any residual nC60 is likely to be oxidized during disinfection process. While the ozonation of nC60 has been studied, little is known about the reaction between nC60 and chlorine. To address this issue, we subjected aqueous nC60 suspensions to chlorination and sequential ozonation/chlorination at ozone dosages of 4.5, 10, 15 and 24 mg O3/mg nC60. The morphology and physicochemical properties of oxidized nC60 aggregates were evaluated by scanning electron microscopy, transmission electron microscopy, UV–visible absorption spectroscopy and X-ray photoelectron spectroscopy (XPS). We found that while the particles in the as-prepared nC60 were predominantly spheres, the ozonation of nC60 resulted in the formation of irregularly shaped aggregates. The concentration of atomic carbon found by XPS in the nC60 samples decreased from 92 % for the as-prepared nC60 to 50 % for the aggregates ozonated at 24 mg O3/mg nC60 and then chlorinated at 68 mg Cl2/L and allowed to react for 100 min. The presence of Cl atoms covalently bonded to C atoms was confirmed by XPS peaks corresponding to a binding energy (E b) of 200.1–202.4 eV. This demonstrates the need to better assess and monitor the formation of potentially toxic chlorinated disinfection by-products from carbon nanomaterials during water treatment. 相似文献
275.
Philippe Lucas‐Picher Simon Lachance‐Cloutier Richard Arsenault Annie Poulin Simon Ricard Richard Turcotte Franois Brissette 《Journal of the American Water Resources Association》2021,57(1):32-56
In spring 2011, an unprecedented flood hit the complex eastern United States (U.S.)–Canada transboundary Lake Champlain–Richelieu River (LCRR) Basin, destructing properties and inducing negative impacts on agriculture and fish habitats. The damages, covered by the Governments of Canada and the U.S., were estimated to C$90M. This natural disaster motivated the study of mitigation measures to prevent such disasters from reoccurring. When evaluating flood risks, long‐term evolving climate change should be taken into account to adopt mitigation measures that will remain relevant in the future. To assess the impacts of climate change on flood risks of the LCRR basin, three bias‐corrected multi‐resolution ensembles of climate projections for two greenhouse gas concentration scenarios were used to force a state‐of‐the‐art, high‐resolution, distributed hydrological model. The analysis of the hydrological simulations indicates that the 20‐year return period flood (corresponding to a medium flood) should decrease between 8% and 35% for the end of the 21st Century (2070–2099) time horizon and for the high‐emission scenario representative concentration pathway (RCP) 8.5. The reduction in flood risks is explained by a decrease in snow accumulation and an increase in evapotranspiration expected with the future warming of the region. Nevertheless, due to the large climate inter‐annual variability, short‐term flood probabilities should remain similar to those experienced in the recent past. 相似文献
276.
Jette Reeg Simon Heine Christine Mihan Sean McGee Thomas G. Preuss Florian Jeltsch 《Environmental Sciences Europe》2018,30(1):44
Background
Semi-natural plant communities such as field boundaries play an important ecological role in agricultural landscapes, e.g., provision of refuge for plant and other species, food web support or habitat connectivity. To prevent undesired effects of herbicide applications on these communities and their structure, the registration and application are regulated by risk assessment schemes in many industrialized countries. Standardized individual-level greenhouse experiments are conducted on a selection of crop and wild plant species to characterize the effects of herbicide loads potentially reaching off-field areas on non-target plants. Uncertainties regarding the protectiveness of such approaches to risk assessment might be addressed by assessment factors that are often under discussion. As an alternative approach, plant community models can be used to predict potential effects on plant communities of interest based on extrapolation of the individual-level effects measured in the standardized greenhouse experiments. In this study, we analyzed the reliability and adequacy of the plant community model IBC-grass (individual-based plant community model for grasslands) by comparing model predictions with empirically measured effects at the plant community level.Results
We showed that the effects predicted by the model IBC-grass were in accordance with the empirical data. Based on the species-specific dose responses (calculated from empirical effects in monocultures measured 4 weeks after application), the model was able to realistically predict short-term herbicide impacts on communities when compared to empirical data.Conclusion
The results presented in this study demonstrate an approach how the current standard greenhouse experiments—measuring herbicide impacts on individual-level—can be coupled with the model IBC-grass to estimate effects on plant community level. In this way, it can be used as a tool in ecological risk assessment.277.
Glenn Lurman Till Blaser Miles Lamare Koh-Siang Tan Hans Poertner Lloyd S. Peck Simon A. Morley 《Marine Biology》2010,157(8):1705-1712
Temperature and mitochondrial plasticity are well studied in fishes, but little is known about this relationship in invertebrates.
The effects of habitat temperature on mitochondrial ultrastructure were examined in three con-familial limpets from the Antarctic
(Nacella concinna), New Zealand (Cellana ornata), and Singapore (Cellana radiata). The effects of seasonal changes in temperature were also examined in winter and summer C. ornata. Stereological methods showed that limpet pedal myocytes were 1–2 orders of magnitude smaller in diameter (≈3.5 μm) than
in vertebrates, and that the diameter did not vary as a function of temperature. Mitochondrial volume density (Vv(mt,f)) was approximately 2–4 times higher in N. concinna (0.024) than in the other species (0.01 and 0.006), which were not significantly different from each other. Mitochondrial
cristae surface density (Sv(im,mt)) was significantly lower in summer C. ornata (24.1 ± 0.50 μm2 μm−3) than both winter C. ornata (32.3 ± 0.95 μm2 μm−3) and N. concinna (34.3 ± 4.43 μm2 μm−3). The surface area of mitochondrial cristae per unit fibre volume was significantly higher in N. concinna, due largely to the greater mitochondrial volume density. These results and previous studies indicate that mitochondrial
proliferation in the cold is a common, but not universal response by different species from different thermal habitats. Seasonal
temperature decreases on the other hand, leading preferentially to an increase in cristae surface density. Stereological measures
also showed that energetic reserves, i.e. lipid droplets and glycogen in the pedal muscle changed greatly with season and
species. This was most likely related to gametogenesis and spawning. 相似文献
278.
Samuel C. Nicol Iadine Chadès Simon Linke Hugh P. Possingham 《Ecological modelling》2010,221(21):2531-2536
When looking for the best course of management decisions to efficiently conserve metapopulation systems, a classic approach in the ecology literature is to model the optimisation problem as a Markov decision process and find an optimal control policy using exact stochastic dynamic programming techniques. Stochastic dynamic programming is an iterative procedure that seeks to optimise a value function at each timestep by evaluating the benefits of each of the actions in each state of the system defined in the Markov decision process.Although stochastic dynamic programming methods provide an optimal solution to conservation management questions in a stochastic world, their applicability in metapopulation problems has always been limited by the so-called curse of dimensionality. The curse of dimensionality is the problem that adding new state variables inevitably results in much larger (often exponential) increases in the size of the state space, which can make solving superficially small problems impossible. The high computational requirements of stochastic dynamic programming methods mean that only simple metapopulation management problems can be analysed. In this paper we overcome the complexity burden of exact stochastic dynamic programming methods and present the benefits of an on-line sparse sampling algorithm proposed by Kearns, Mansour and Ng (2002). The algorithm is particularly attractive for problems with large state spaces as the running time is independent of the size of the state space of the problem. This appealing improvement is achieved at a cost: the solutions found are no longer guaranteed to be optimal.We apply the algorithm of Kearns et al. (2002) to a hypothetical fish metapopulation problem where the management objective is to maximise the number of occupied patches over the management time horizon. Our model has multiple management options to combat the threats of water abstraction and waterhole sedimentation. We compare the performance of the optimal solution to the results of the on-line sparse sampling algorithm for a simple 3-waterhole case. We find that three look-ahead steps minimises the error between the optimal solution and the approximation algorithm. This paper introduces a new algorithm to conservation management that provides a way to avoid the effects of the curse of dimensionality. The work has the potential to allow us to approximate solutions to much more complex metapopulation management problems in the future. 相似文献
279.
Simon L. Axelsen Alan Shapiro Evgeni Fedorovich Han van Dop 《Environmental Fluid Mechanics》2010,10(4):387-414
An analytical model for katabatic flow induced by cold strip of finite width in the cross-slope direction but of infinite
extent in the downslope direction is presented. The fluid is assumed to have a constant (eddy) viscosity, and the Coriolis
force is neglected. A numerical simulation has been used to verify the model, which is shown to revert to the classical Prandtl
model if the strip width goes to infinity. The effects of the strip width and slope angle on the katabatic flow are studied.
The buoyancy and downslope velocity reach maximum values at the centre of the strip, and spread outwards in the cross-slope
direction. The downslope wind maximum weakens for narrow strips and shallow slopes. In contrast to the Prandtl solution, which
shows a counter flow above the wind maximum, our model predicts the counter flow to occur outside the strip. The cross-slope
variation in the surface forcing induces cross-slope and slope-normal velocities, which are manifested in vortices at the
strip edges. Below the wind maximum, the fluid above the cooling surface descends and moves toward the strip edge where it
is detrained from the strip region. Replenishment of fluid into the strip region takes place above the wind maximum. 相似文献
280.
The challenges faced by coastal protected areas in both promoting highly attractive sites and preserving the natural attributes of these sites have been given a new dimension with the opportunities presented by ecotourism. Realising the market potential of a protected area and, at the same time, conserving the unique features of an area is a difficult task. This paper explores the possibilities that backpacker tourism may offer the Quarantine Station in Sydney Harbour National Park, in Australia. The Quarantine Station is a significant cultural heritage site that is located in a sensitive coastal national park within Sydney's metropolitan area. 相似文献