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61.
Brazil hosts the largest expanse of tropical ecosystems within protected areas (PAs), which shelter biodiversity and support traditional human populations. We assessed the vulnerability to climate change of 993 terrestrial and coastal-marine Brazilian PAs by combining indicators of climatic-change hazard with indicators of PA resilience (size, native vegetation cover, and probability of climate-driven vegetation transition). This combination of indicators allows the identification of broad climate-change adaptation pathways. Seventeen PAs (20,611 km2) were highly vulnerable and located mainly in the Atlantic Forest (7 PAs), Cerrado (6), and the Amazon (4). Two hundred fifty-eight PAs (756,569 km2), located primarily in Amazonia, had a medium vulnerability. In the Amazon and western Cerrado, the projected severe climatic change and probability of climate-driven vegetation transition drove vulnerability up, despite the generally good conservation status of PAs. Over 80% of PAs of high or moderate vulnerability are managed by indigenous populations. Hence, besides the potential risks to biodiversity, the traditional knowledge and livelihoods of the people inhabiting these PAs may be threatened. In at least 870 PAs, primarily in the Atlantic Forest and Amazon, adaptation could happen with little or no intervention due to low climate-change hazard, high resilience status, or both. At least 20 PAs in the Atlantic Forest, Cerrado, and Amazonia should be targeted for stronger interventions (e.g., improvement of ecological connectivity), given their low resilience status. Despite being a first attempt to link vulnerability and adaptation in Brazilian PAs, we suggest that some of the PAs identified as highly or moderately vulnerable should be prioritized for testing potential adaptation strategies in the near future.  相似文献   
62.
The genetic population structure of the recently introduced Asian clam, Potamocorbula amurensis, in San Francisco Bay was described using starch gel electrophoresis at eight presumptive loci. Specimens were taken from five environmentally distinct sites located throughout the bay. The population maintains a high degree of genetic variation, with a mean heterozygosity of 0.295, a mean polymorphism of 0.75, and an average of 3.70 alleles per locus. The population is genetically homogeneous, as evidenced from genetic distance values and F-statistics. However, heterogeneity of populations was indicated from a contingency chi-square test. Significant deviations from Hardy-Weinberg equilibrium and heterozygote deficiencies were found at the Lap-1 locus for all populations and at the Lap-2 locus for a single population. High levels of variability could represent a universal characteristic of invading species, the levels of variability in the source population(s), and/or the dynamics of the introduction. Lack of differentiation between subpopulations may be due to the immaturity of the San Francisco Bay population, the general purpose phenotype genetic strategy of the species, high rates of gene flow in the population, and/or the selective neutrality of the loci investigated.  相似文献   
63.
The rapid urbanization of the Earth has led to highly populated cities that act as concentrated centers of anthropogenic stressors on the environment. Much of these stressors originate from nonlinear coupling between man-made urban elements (i.e., networks of engineering and socio-economic infrastructures) and the natural environment. An urban area can be treated as a system of urban elements (or elemental systems), and simple interactions between the latter may lead to complex outcomes, known as emergent properties, in the former. Emergent properties of urban systems play an important role in determining their resilience and sustainability, studies on which require an in-depth knowledge of dynamics, interdependencies and feedbacks of urban elements as well as development of quantitative holistic models to integrate such knowledge to predict the overall system response. To facilitate this demanding effort, it is proposed to initiate a new sub-discipline within the discipline of Earth System Engineering, with the portmanteau of Polimetrics, to deal with quantitative scientific aspects of urban systems. This paper discusses two examples of polimetrics related to urban fluid flows. The first deals with the urban heat island and the other with storm surges in coastal cities.  相似文献   
64.
Pulmonary function of approximately 200 school children in Steubenville, OH was measured before and immediately following air pollution alerts in the fall of 1978 and 1979. TSP concentrations exceeded the National Primary Ambient Air Quality 24 h standards in 1978. SO2 exceeded the standard in 1979. The children were then reexamined in three weekly visits following each alert. Estimated mean Forced Vital Capacity (FVC) was approximately 2% lower following each alert, although the lowest means were observed one to two weeks after the episodes. Forced Expired Volume in 0.75 sec (FEV0.75) did not change during the 1978 study, but was 4% lower immediately following the 1979 alert. The children were measured again in five weekly examinations in the spring and fall of 1980. Air pollution levels did not exceed the standards on either occasion. In the spring of 1980, estimated mean FVC and FEV0.75 showed a decline similar to that observed following the alerts in 1978 and 1979. In the fall of 1980, there were no significant differences in the estimated mean FVC or FEV0.75 between the examinations. A total of 335 children were tested in the four studies, including 194 who participated in more than one study. The evidence for each child from all the studies was combined in a regression analysis of pulmonary function on TSP and SO2 average concentrations in the previous 24 h. The distribution of the individual regression coefficients was centered significantly below zero, implying a decrease in pulmonary function with increasing TSP and SO2 concentrations. The magnitude of the median change was less than 1% of the mean FVC and FEV0.75 over the range of TSP and SO2 concentrations observed.  相似文献   
65.
Windblown dust is known to impede visibility, deteriorate air quality and modify the radiation budget. Arid and semiarid areas with unpaved and unvegetated land cover are particularly prone to windblown dust, which is often attributed to high particulate matter (PM) pollution in such areas. Yet, windblown dust is poorly represented in existing regulatory air quality models. In a study by the authors on modeling episodic high PM events along the US/Mexico border using the state-of-the-art CMAQ/MM5/SMOKE air quality modeling system [Choi, Y.-J., Hyde, P., Fernando, H.J.S., 2006. Modeling of episodic particulate matter events using a 3D air quality model with fine grid: applications to a pair of cities in the US/Mexico border. Atmospheric Environment 40, 5181–5201], some of the observed PM10 NAAQS exceedances were inferred as due to windblown dust, but the modeling system was incapable of dealing with time-dependent episodic dust entrainment during high wind periods. In this paper, a time-dependent entrainment parameterization for windblown dust is implemented in the CMAQ/MM5/SMOKE modeling system with the hope of improving PM predictions. An approach for realizing windblown dust emission flux for each grid cell over the study domain on an hourly basis, which accounts for the influence of factors such as soil moisture content, atmospheric stability and wind speed, is presented in detail. Comparison of model predictions with observational data taken at a pair of US/Mexico border towns shows a clear improvement of model performance upon implementation of the dust emission flux parameterization.  相似文献   
66.
Miranda B  Díaz E  Ordóñez S  Vega A  Díez FV 《Chemosphere》2007,66(9):1706-1715
The performance of bulk chromium oxide is compared with that of a Mn commercial catalyst for the deep oxidation of trichloroethene (1000-2500ppmv, 55h(-1) space velocity) in air, in dry and wet (20000ppm of H(2)O) conditions, in terms of activity, selectivity and stability. Chromium oxide was found to be more active (on a catalyst weight basis), however its activity decreases continuously with time on stream. The presence of water increases its stability, the Mn catalyst showing the opposite behaviour. The effect of water on the Cr catalyst can be explained according to the Deacon equilibrium, as the presence of water tends to decrease the Cl(2) concentration, assumed to be responsible of the catalyst deactivation. Regarding to the selectivity, the Mn catalyst yields C(2)Cl(4), CCl(4) and CHCl(3) as organochlorinated by-products, whereas chromium oxide produces only trace amounts of CCl(4). Simple power-law kinetics expressions (first-order for Mn and zero-order for Cr) provide fairly good fits for the evolution of the conversion with the temperature. Furthermore, the kinetic behaviour of chromium oxide can be represented with a Langmuir-Hinshelwood model taking into account the chlorine inhibitory effect.  相似文献   
67.
From 1992–1996, 3204 artificial roosts of 9 types were placed in woodlots near Indianapolis International Airport in an effort to provide habitat for the federally-endangered Indiana myotis (Myotis sodalis) and to determine the feasibility of using these structures to manage bats in a rapidly developing suburban area. We surveyed these structures at least annually during 1992–1999 and found only northern myotis (Myotis septentrionalis) regularly using the structures. Four other species were occasionally found using structures including big brown bats (Eptesicus fuscus, n = 14 individuals), little brown myotis (Myotis lucifugus, n = 2), Indiana myotis (Myotis sodalis, n = 2), and one silver-haired bat (Lasionycteris noctivagans). Single, triple, and Missouri-style batboxes were almost always used, rather than the six other types of experimental roosts that had been in place. However, after 10 years in place, it appears that Indiana bats are acclimated to boxes, as 6 of them were being used rather regularly by Indiana myotis. Bat boxes can provide roosting habitat for some species under conditions where few suitable roosts exist, but assuring an abundance of natural habitats is usually more desirable for conservation of tree-roosting bats.  相似文献   
68.
Power-line grids are increasingly expanding worldwide, as well as their negative impacts on avifauna, namely the direct mortality through collision and electrocution, the reduction of breeding performance, and the barrier effect. On the other hand, some bird species can apparently benefit from the presence of power lines, for example perching for hunting purposes or nesting on electricity towers. In this perspective essay, we reviewed the scientific literature on both costs and benefits for avifauna coexisting with power lines. Overall, we detected a generalized lack of studies focusing on these costs or benefits at a population level. We suggest that a switch in research approach to a larger spatio-temporal scale would greatly improve our knowledge about the actual effects of power lines on bird populations. This research approach would facilitate suitable landscape planning encompassing both mitigation of costs and promotion of benefits for bird populations coexisting with power lines. For example, the strategic route planning of electricity infrastructures would limit collision risk or barrier effects for threatened bird populations. Concurrently, this strategic route planning would promote the range expansion of threatened populations of other bird species, by providing nesting structures in treeless but potentially suitable landscapes. We suggest establishing a collaborative dialogue among the scientific community, governments, and electricity companies, with the aim to produce a win–win scenario in which both biodiversity conservation and infrastructure development are integrated in a common strategy.  相似文献   
69.
Air inside poultry houses must be removed on a regular basis to prevent excess of heat, particles and noxious gases that can imperil animals. To cope with this issue, natural ventilation could be an effective method when assisted by accurate predictions. This study investigates air discharges caused by natural ventilation of a poultry house by means of a three-dimensional computational fluid dynamics (CFD) model. It solves the governing equations of momentum, heat and mass transport, radiative transfers and animal-generated heat. Wind directions of 0°, 36° and 56° (0° corresponds to a wind blowing perpendicular to the ridgeline) were investigated; the CFD model predictions achieved a RMSE of 1.2 °C and 0.6 g[H2O] kg?1 [dry air] for internal temperature and absolute humidity, respectively, when air blew with an angle of 36°. Air renewal rates (ARR) were 39.5 (±?1.9), 34.9 (±?2.2) and 33.6 (±?1.7) volumes of the building per hour, when air blew at 0°, 36° and 56°, respectively. Such ARR predictions served to know how the gases contained in air would likely spread downstream from the building in order to define regions of potentially high gas concentration that could endanger neighbouring habitable facilities.  相似文献   
70.
A forensic approach was used to evaluate sediments from Portão Stream, including analysis of metals, carbon (C) and nitrogen (N) stable isotopes, and C:N ratios. Samples collected at various points located along the stream were tested in order to investigate a possible illegal leachate input. The studied stream is heavily impacted by sewage and industrial discharges from two cities along its course. Among the metals analyzed, chromium (Cr) was noticeably the main pollutant, showing the highest levels, above regulatory limits, downstream from some potential sources of effluents enriched with this metal. Isotope analyses revealed a general trend of depletion in the heavier isotope along the stream for C and N. The exception was one point near a hazardous waste landfill, where relatively more enriched δ13C and δ15N values were found. The isotope and metal analysis results indicated that this site was affected by a particular source, demonstrating the combination of these parameters could be used for the discrimination of sources in a heavily polluted stream. Nevertheless, further investigations are necessary to provide a comprehensive evaluation of the biogeochemical processes involved in the incorporation of leachate in sediments to use this analysis as evidence for the illegal leachate discharge.  相似文献   
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