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Christopher Essex 《Planetary and Space Science》1984,32(8):1035-1043
Even though irreversible thermodynamics is meant to be a universal theory for nonequilibrium processes, that theory has not taken nonequilibrium radiation processes, which can normally be ignored, into account; thus it is primarily a theory for matter. When the simple bilinear entropy production rate of irreversible thermodynamics is modified, to account for the entropy production due to radiation while preserving local equilibrium for matter, the simple bilinear form of that rate, on which the current theory depends, is lost. Despite substantial compromises, generalized definitions for forces and fluxes cannot restore that simple homogeneous bilinear form, nor do they succeed in generating even generalized bilinearity in the entropy production rates for some problems concerning radiation. The possibility of a broader nonequilibrium theory is suggested by radiation problems, characterized by an example due to Planck, where those generalizations fail and the entropy production rate is a minimum in the steady state. 相似文献
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Jamey E. Redding Roxanna L. Myers-Miller David M. Baker Marilyn Fogel Laurie J. Raymundo Kiho Kim 《Marine pollution bulletin》2013
The goals of this study were to evaluate the contribution of sewage-derived N to reef flat communities in Guam and to assess the impact of N inputs on coral disease. We used stable isotope analysis of macroalgae and a soft coral, sampled bimonthly, as a proxy for N dynamics, and surveyed Porites spp., a dominant coral taxon on Guam’s reefs, for white syndrome disease severity. Results showed a strong influence of sewage-derived N in nearshore waters, with δ15N values varying as a function of species sampled, site, and sampling date. Increases in sewage-derived N correlated significantly with increases in the severity of disease among Porites spp., with δ15N values accounting for more than 48% of the variation in changes in disease severity. The anticipated military realignment and related population increase in Guam are expected to lead to increased white syndrome infections and other coral diseases. 相似文献
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Intensively managed coniferous afforestation schemes cause profound changes to the components of an ecosystem. This paper reviews the ecological effects of afforestation around Burrator Reservoir, Dartmoor (1916–1990). The human management decisions concerning the development of the plantations are considered, together with the ecological consequences. This research shows that the less intensive management regime for the forests at Burrator has resulted in a woodland ecosystem with a more complicated structure than might have been expected from a more intensively managed scheme. An assessment of the potential changes to forest management following water privatization is also made, together with a consideration of the possible ecological impacts. 相似文献
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Jacquez Geoffrey M. Essex Aleksander Curtis Andrew Kohler Betsy Sherman Recinda El Emam Khaled Shi Chen Kaufmann Andy Beale Linda Cusick Thomas Goldberg Daniel Goovaerts Pierre 《Journal of Geographical Systems》2017,19(3):197-220
Journal of Geographical Systems - As the volume, accuracy and precision of digital geographic information have increased, concerns regarding individual privacy and confidentiality have come to the... 相似文献
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Problems of sustainability of water supply in tourist resorts are becoming an increasingly common and important issue in applied geography and environmental management. This paper examines the relationships between tourism and water supply on the Mediterranean island of Mallorca, discussing both the scale of the problem and recent measures to find a solution, particularly the proposed Hydrological Plan for the Balearic Islands (published in 1998/9). Since Mallorca lies in an area likely to be seriously affected by future climate change, its potential effects are discussed and evaluated. One of the most critical problems relates to the coarse spatial resolution of general circulation models for predicting precipitation in an area where precipitation regimes grade steeply from semi-arid to humid temperate. However, it is likely that a continuation of the marked inter-annual and decadal-scale variability in precipitation seen during the recent past probably poses a greater threat to Mallorca’s water supply than the more gradual, progressive change typically predicted to accompany future global warming. Similarly, continued over-exploitation of coastal aquifers will be more critical to water quality issues than the direct impacts of any future sea level rise, although the latter would undoubtedly exacerbate these effects. The conclusion discusses the controversial new ecotasa (‘ecotax’), due to be imposed on Mallorca’s tourist industry in 2002, which is likely to represent only a partial solution to the long-term water supply problem. As the physical, cultural and economic environments of Mallorca are typical of much of the Mediterranean region, the implications of this issue extend well beyond the island’s shores. 相似文献
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Christopher Essex 《Pure and Applied Geophysics》1991,135(1):125-133
It has become widely accepted that an increase in the infrared optical depth of the atmosphere must lead to an increase in the global surface temperature. It is demonstrated here that this need not be so, implying a limited predictive capability for modern climate models. 相似文献
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Allan Kolker Mark A. Engle William H. Orem Joseph E. Bunnell Harry E. Lerch David P. Krabbenhoft Mark L Olson Jamey D. McCord 《Geostandards and Geoanalytical Research》2008,32(3):279-293
Compliance with U.S. air quality regulatory standards for atmospheric fine particulate matter (PM2.5) is based on meeting average 24 hour (35 μ m?3) and yearly (15 μg m?3) mass‐per‐unit‐volume limits, regardless of PM2.5 composition. Whereas this presents a workable regulatory framework, information on particle composition is needed to assess the fate and transport of PM2.5 and determine potential environmental/human health impacts. To address these important non‐regulatory issues an integrated approach is generally used that includes (1) field sampling of atmospheric particulate matter on filter media, using a size‐limiting cyclone, or with no particle‐size limitation; and (2) chemical extraction of exposed filters and analysis of separate particulate‐bound fractions for total mercury, trace elements and organic constituents, utilising different USGS laboratories optimised for quantitative analysis of these substances. This combination of sampling and analysis allowed for a more detailed interpretation of PM2.5 sources and potential effects, compared to measurements of PM2.5 abundance alone. Results obtained using this combined approach are presented for a 2006 air sampling campaign in Shenandoah National Park (Virginia, USA) to assess sources of atmospheric contaminants and their potential impact on air quality in the Park. PM2.5 was collected at two sampling sites (Big Meadows and Pinnacles) separated by 13.6 km. At both sites, element concentrations in PM25 were low, consistent with remote or rural locations. However, element/Zr crustal abundance enrichment factors greater than 10, indicating anthropogenic input, were found for Hg, Se, S, Sb, Cd, Pb, Mo, Zn and Cu, listed in decreasing order of enrichment. Principal component analysis showed that four element associations accounted for 84% of the PM2.5 trace element variation; these associations are interpreted to represent: (1) crustal sources (Al, REE); (2) coal combustion (Se, Sb), (3) metal production and/or mobile sources (Mo, Cd, Pb, Cu, Zn) and (4) a transient marine source (Sr, Mg). Concentrations of Hg in PM2.5 at background levels in the single pg m?3 were shown by collection and analysis of PM2.5 on filters and by an automated speciation analyser set up at the Big Meadows air quality site. The speciation unit revealed periodic elevation of reactive gaseous mercury (RGM) that co‐occurred with peaks in SO2, indicating an anthropogenic source. GC/MS total ion current chromatograms for the two sites were quite similar indicating that organic signatures were regional in extent and/or that the same compounds were present locally at each site. Calculated carbon preference index values for n‐alkanes indicated that plant waxes rather than anthropogenic sources, were the dominant alkane source. Polycyclic aromatic hydrocarbons (PAHs) were detected, with a predominance of non‐alkylated, and higher molecular weight PAHs in this fraction, suggestive of a combustion source (fossil fuel or forest fires). 相似文献
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Jamey Essex 《Geoforum》2008,39(4):1625-1636
The institutions, practices, and discourses of US development policy and foreign assistance are undergoing profound changes. Central to these has been the creation of a new framework for foreign aid, built around a complex taxonomy of developing states and governance issue areas, with geographic and governance categories predicated on notions of state stability and fragility, strategic geopolitical position, and development progress. Given its long-standing position as the primary federal agency responsible for development and foreign aid, the US Agency for International Development (USAID) has played an important role in these policy changes, even as its political status and standing have suffered in recent years. The new framework is beset by contradictions, stemming both from the problematic relationship between development, security, and liberalization in agency rhetoric and strategies, and from intensive restructuring processes affecting USAID’s internal character and external relations. This paper investigates the new framework for foreign aid, linking internal restructuring at USAID to broader trends in state development strategies. I argue that shifts in US development and aid policy - toward emphases on “transformational development” abroad and centralization over strategic decision making domestically, crystallized in the new framework - are based in contradictory understandings of aid deservedness that stem from the tensions between economic and geopolitical aims within the current security-focused US state project of neoliberalization. These contradictions and tensions are displaced onto USAID via the Foreign Assistance Framework. 相似文献
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