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811.
Far-from-equillibrium oscillating chemical reactions are among the simplest systems showing complex behaviors and emergent properties. This class of reactions is often employed to mimic and understand the mechanisms of a great variety of biological processes. In this context, pattern formation due to the coupling between reaction and transport phenomena represent an active and promising research area. In this paper, we present results coming from experiments where we tried to blend the structural properties of self-assembled matrixes (sodium dodecyl sulphate micelles and phospholipid bilayers) together with the evolutive peculiarities of the Belousov–Zhabotinsky reaction. A series of interesting dynamical behaviors, like spatio-temporal chaos, stationary patterns and segmented waves, were found in reaction–diffusion and reaction–diffusion–convection experiments. 相似文献
812.
Air quality and related health effects are not only affected by policies directly addressed at air pollution but also by other environmental strategies such as climate mitigation. This study addresses how different climate policy pathways indirectly bear upon air pollution in terms of improved human health in Europe. To this end, we put in perspective mitigation costs and monetised health benefits of reducing PM2.5 (particles less than 2.5 μm in diameter) and ozone concentrations.Air quality in Europe and related health impacts were assessed using a comprehensive modelling chain, based on global and regional climate and chemistry-transport models together with a health impact assessment tool. This allows capturing both the impact of climate policy on emissions of air pollutants and the geophysical impact of climate change on air quality.Results are presented for projections at the 2050 horizon, for a set of consistent air pollution and climate policy scenarios, combined with population data from the UN's World Population Prospects, and are expressed in terms of morbidity and mortality impacts of PM2.5 and ozone pollution and their monetised damage equivalent.The analysis shows that enforcement of current European air quality policies would effectively reduce health impacts from PM2.5 in Europe even in the absence of climate policies (life years lost from the exposure to PM2.5 decrease by 78% between 2005 and 2050 in the reference scenario), while impacts for ozone depend on the ambition level of international climate policies. A move towards stringent climate policies on a global scale, in addition to limiting global warming, creates co-benefits in terms of reduced health impacts (68% decrease in life years lost from the exposure to PM2.5 and 85% decrease in premature deaths from ozone in 2050 in the mitigation scenario relative to the reference scenario) and air pollution cost savings (77%) in Europe. These co-benefits are found to offset at least 85% of the additional cost of climate policy in this region. 相似文献
813.
Water quality modelling is an effective tool to investigate, describe and predict the ecological state of an aquatic ecosystem. Various environmental variables may simultaneously affect water quality. Appropriate selection of a limited number of key-variables facilitates cost-effective management of water resources. This paper aims to determine (and analyse the effect of) the major environmental variables predicting ecological water quality through the application of fuzzy models. In this study, a fuzzy logic methodology, previously applied to predict species distributions, was extended to model environmental effects on a whole community. In a second step, the developed models were applied in a more general water management context to support decision and policy making. A hill-climbing optimisation algorithm was applied to relate ecological water quality and environmental variables to the community indicator. The optimal model was selected based on the predictive performance (Cohen’s Kappa), ecological relevance and model’s interpretability. Moreover, a sensitivity analysis was performed as an extra element to analyse and evaluate the optimal model. The optimal model included the variables land use, chlorophyll and flow velocity. The variable selection method and sensitivity analysis indicated that land use influences ecological water quality the most and that it affects the effect of other variables on water quality to a high extent. The model outcome can support spatial planning related to land use in river basins and policy making related to flows and water quality standards. Fuzzy models are transparent to a wide range of users and therefore may stimulate communication between modellers, river managers, policy makers and stakeholders. 相似文献
814.
In 2011, a legal settlement required the U.S. Fish and Wildlife Service (USFWS) to develop a series of work plans to assess a backlog of candidate species for protection under the U.S. Endangered Species Act. Using the resulting USFWS Fiscal Year 2013–2018 work plan, which included 261 candidate species, we identified and analyzed pre-listing candidate conservation plans (PLCP) to determine their characteristics and evaluate the use of market-based mechanisms. Among the 34 PLCPs identified, we found that species-based conservation plans were more common than habitat-based plans, and market-based conservation approaches were infrequently implemented. Inconsistencies in plan documentation were present throughout the USFWS’s online portal, and not all documentation was publicly accessible. Lastly, we found that many states had implemented their own endangered species programs or initiated conservation plans through a state agency. Our work informs the recently-adopted USFWS pre-listing conservation policy and highlights needed improvements in tracking large numbers of at-risk species as they become the subject of regulations. Increased transparency and consistency in conservation plan databases, coupled with increased accessibility, will improve future at-risk species planning. 相似文献
815.
How does the resilience concept of nested relationships (panarchy) contribute to sustainability science and policy? Resilience at a particular level of organization, the community level in our case, is influenced by internal processes at that level. But it is also impacted by actions at lower levels of organization (individuals, households), and by drivers of change originating at higher levels (national level policies, globalized market forces). We focus on community level social-ecological systems, looking upwards and downwards from there. Our objective is to explore the connections of the community to other levels, the ways in which community resilience is impacted, and the implications of this for sustainability. Conventional disciplines specialize at different levels, a barrier to investigating multi-level interactions. Use of the panarchy concept helps contribute to the interdisciplinary understanding of resilience at the community (and other levels) by drawing attention to cross-scale relationships. From the effect of individual leadership to the implication of pandemics that move swiftly across levels, examples illustrate a diversity of ways in which community resilience is shaped in a multi-level world. 相似文献
816.
Colin D. Brown Wendy van Beinum 《Environmental pollution (Barking, Essex : 1987)》2009,157(12):3314-3324
Transport of pesticides from point of application via sub-surface drains can contribute significantly to contamination of surface waters. Results of 23 field drainage experiments undertaken at sites across Europe were collated and analysed by residual maximum likelihood. Both maximum concentration of pesticide in drainflow (n = 167) and seasonal loss of pesticide to drains (n = 97) were significantly related to strength of pesticide sorption to soil, half-life of the pesticide in soil, the interval between application and first drainflow and the clay content of the soil. The statistical models accounted for 71% of the variability in both maximum concentration and seasonal load. Next, the dataset was used to evaluate the current methodology for assessment of aquatic exposure used in pesticide registration in Europe. Simulations for seven compounds with contrasting properties showed a good correspondence with field measurements. Finally, the review examines management approaches to reduce pesticide transport via sub-surface drains. Despite a large amount of work in this area, there are few dependable mitigation options other than to change application rate or timing or to restrict use of a compound in the most vulnerable situations. 相似文献
817.
E. G. Kolomyts 《Russian Journal of Ecology》2006,37(6):391-401
On the basis of the GISS prognostic climatic model, landscape-ecological scenarios concerning the immediate future of the region are considered in the forms of cartographic and analytical models. These scenarios predict a growing thermoarid bioclimatic trend accompanied by a general northward displacement of zonal boundaries, with corresponding acceleration of the biological cycle and increase in the productivity of boreal forests. 相似文献
818.
Operational sex ratio versus gender density as determinants of copulation duration in the walnut fly,Rhagoletis juglandis (Diptera: Tephritidae) 总被引:5,自引:0,他引:5
In laboratory and field studies of the walnut fly, Rhagoletis juglandis Cresson (Diptera: Tephritidae), we assessed the effect of operational sex ratio on copulation duration and partitioned the
sex ratio effect into component effects due to male density and female density. In our first laboratory experiment, results
were clearly consistent with theoretical expectation: increases in male density were associated with significant increases
in copulation duration while increases in female density were associated with significant decreases in copulation duration.
These component effects yielded a striking composite effect of operational sex ratio (OSR) on copulation duration in which
male-biased ratios were associated with low frequencies of short copulations and female-biased ratios were associated with
high frequencies of short copulations. Consistent with a priori expectations concerning costs of territorial behavior, the
effect of male density on copulation duration was stronger than that of female density. There was no significant interaction
between the effects of gender density on copulation duration: each gender density contributed additively to the composite
OSR effect on copulation duration. In contrast to the effect of OSR, overall density had little effect. Field data corroborated
these findings fully and showed additionally that OSR in the vicinity of fruit tended in nature to be male-biased. In a second
laboratory experiment, we measured copulation duration for individuals exposed alternately to male-biased and female-biased
ratios. Individual flies consistently copulated for longer in male-biased environments than in female-biased ones. We propose
that this plasticity permits individuals to track changes in local sex ratio over space and time and respond appropriately.
Received: 15 November 1995/Accepted after revision: 27 April 1996 相似文献
819.
Managing climate change risks in New York City’s water system: assessment and adaptation planning 总被引:4,自引:0,他引:4
Cynthia Rosenzweig David C. Major Kate Demong Christina Stanton Radley Horton Melissa Stults 《Mitigation and Adaptation Strategies for Global Change》2007,12(8):1391-1409
Managing risk by adapting long-lived infrastructure to the effects of climate change must become a regular part of planning
for water supply, sewer, wastewater treatment, and other urban infrastructure during this century. The New York City Department
of Environmental Protection (NYCDEP), the agency responsible for managing New York City’s (NYC) water supply, sewer, and wastewater
treatment systems, has developed a climate risk management framework through its Climate Change Task Force, a government-university
collaborative effort. Its purpose is to ensure that NYCDEP’s strategic and capital planning take into account the potential
risks of climate change—sea-level rise, higher temperature, increases in extreme events, changes in drought and flood frequency
and intensity, and changing precipitation patterns—on NYC’s water systems. This approach will enable NYCDEP and other agencies
to incorporate adaptations to the risks of climate change into their management, investment, and policy decisions over the
long term as a regular part of their planning activities. The framework includes a 9-step Adaptation Assessment procedure.
Potential climate change adaptations are divided into management, infrastructure, and policy categories, and are assessed
by their relevance in terms of climate change time-frame (immediate, medium, and long term), the capital cycle, costs, and
other risks. The approach focuses on the water supply, sewer, and wastewater treatment systems of NYC, but has wide application
for other urban areas, especially those in coastal locations. 相似文献
820.
HENRY LEE II DEBORAH A. REUSSER† JULIAN D. OLDEN‡ SCOTT S. SMITH† JIM GRAHAM§ VIRGINIA BURKETT JEFFREY S. DUKES†† ROBERT J. PIORKOWSKI‡‡ JOHN MCPHEDRAN§§ 《Conservation biology》2008,22(3):575-584
Abstract: Changes in temperature, precipitation, and other climatic drivers and sea-level rise will affect populations of existing native and non-native aquatic species and the vulnerability of aquatic environments to new invasions. Monitoring surveys provide the foundation for assessing the combined effects of climate change and invasions by providing baseline biotic and environmental conditions, although the utility of a survey depends on whether the results are quantitative or qualitative, and other design considerations. The results from a variety of monitoring programs in the United States are available in integrated biological information systems, although many include only non-native species, not native species. Besides including natives, we suggest these systems could be improved through the development of standardized methods that capture habitat and physiological requirements and link regional and national biological databases into distributed Web portals that allow drawing information from multiple sources. Combining the outputs from these biological information systems with environmental data would allow the development of ecological-niche models that predict the potential distribution or abundance of native and non-native species on the basis of current environmental conditions. Environmental projections from climate models can be used in these niche models to project changes in species distributions or abundances under altered climatic conditions and to identify potential high-risk invaders. There are, however, a number of challenges, such as uncertainties associated with projections from climate and niche models and difficulty in integrating data with different temporal and spatial granularity. Even with these uncertainties, integration of biological and environmental information systems, niche models, and climate projections would improve management of aquatic ecosystems under the dual threats of biotic invasions and climate change. 相似文献