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121.
Plantation forests not only impact carbon and water cycles, but also affect biodiversity, livelihoods, and shape regional
economies. Each of these impacts differs across varying scales of analysis. This paper illustrates how forest, climate change
and hydrology debates play out in the context of the forest plantations of Australian black wattle (Acacia mearnsii) in the upper Palni hills of southern India. We outline the contradictory perspectives of different local groups regarding
the impact of plantations on catchment hydrology and water availability, and examine these in relation to changes in the regional
economy and rainfall patterns. Our analysis indicates that changes in these two factors have played a more significant role
than existing wattle plantations in affecting local and regional water availability. We suggest that ongoing debates regarding
forest plantation–hydrology–climate change relationships need to broaden their scope to include changes in regional rainfall
patterns and shifts in regional economic activity. This approach is likely to provide a more realistic assessment of plantation
forests in a dynamic regional context, and offer more resilient strategies for regional landscape and catchment management
under conditions of high variability in rainfall patterns. 相似文献
122.
123.
Alexander Goetz Ph.D. Rudolf F. Pueschel M.S. 《Journal of the Air & Waste Management Association (1995)》2013,63(3):90-95
The role of nucleating particulates in the formation of photochemical aerosols has been studied in a steady, laminar flow of ultrafiltered air containing NO2 and octene-1 in the concentration range of (30 to 170 ppm) when subjected to intense irradiation under isothermal conditions. The particulates consisted of monodisperse polystyrene latex (d = 0.36 μ.) in concentrations similar to those in the atmosphere (6 × 101 to 3 × 103 cm–3); the irradiation intensity varied between (6 to 40 × 103 lumen/liter) and the mean exposure duration between 30 and 180 sec. Samples of the flow prior to and after its photoactivation were withdrawn either by an Aerosol Spectrometer (AS) or by a Royco Aerosol Photometer (PH). While these indications refer thus to the same system, they differ, because the photometric data include all colloidal components in the airborne state, whereas the counts obtained from the AS deposits refer only to the nucleated latex particles. The following pattern becomes evident: The photochemical reaction yields fractional products (less than three percent) which have the tendency to agglomerate (or polymerize) due to their relatively low volatility—independent of the presence or absence of nucleating particulates. In their presence, this reaction becomes kinetically more probable and thus faster, hence the accumulant formation occurs preferably on the nuclei and causes their growth such that, e.g., a 10-fold higher nuclei concentration will produce under the same conditions 10 times the accumulant mass while autonucleation is suppressed. The growth process appears thus principally different from that of fog formation by H2O-condensation, whereas for identical super saturation it is inversely proportional to the nuclear concentration. In the absence of nuclei autonucleation, i.e., self-agglomeration, occurs at a much lesser reaction rate and higher photon demand. The growth rate of the nuclei, when present, depends on the concentration of the oxidation catalyst (NO2), its interaction with the nuclei surface is indicated. Under identical conditions the mass of nuclear accumulant is directly proportional to the concentration of the reactive hydrocarbon, while the growth rate depends on the light intensity and the exposure duration. The findings indicate that density and nature of particulate matter present in an air mass prior or during photo-activation are—aside from the chemical reactant levels—of major significance in aerosol formation. 相似文献
124.
125.
Biodegradable chelate enhances the phytoextraction of copper by Oenothera picensis grown in copper-contaminated acid soils 总被引:2,自引:0,他引:2
Oenothera picensis plants (Fragrant Evening Primrose) grow in the acid soils contaminated by copper smelting in the coastal region of central Chile. We evaluated the effects of the biodegradable chelate MGDA (methylglycinediacetic acid) on copper extraction by O. picensis and on leaching of copper through the soil profile, using an ex situ experiment with soil columns of varying heights. MGDA was applied in four rates: 0 (control), 2, 6 and 10 mmol plant−1. MGDA application significantly increased biomass production and foliar concentration, permitting an effective increase in copper extraction, from 0.09 mg plant−1 in the control, to 1.3 mg plant−1 in the 6 and 10 mmol plant−1 treatments. With 10 mmol plant−1 rate of MGDA, the copper concentration in the leachate from the 30 cm columns was 20 times higher than in the control. For the 60 cm columns, copper concentration was 2 times higher than the control. It can be concluded that at increased soil depths, copper leaching would be minimal and that MGDA applications at the studied rates would not pose a high risk for leaching into groundwater. It can thus be stated that applications of MGDA are an effective and environmentally safe way to improve copper extraction by O. picensis in these soils. 相似文献
126.
Novel catalytic nano-sized materials based on LaCoO(x) perovskite nanoparticles incapsulated in the mesoporous matrix of zirconia were prepared, characterized by physicochemical methods and tested in complete methanol oxidation. LaCoO(x) nanoparticles were prepared inside the mesopores of ZrO(2) by decomposition of bimetallic La-Co glycine precursor complexes. The catalysts have been studied by diffuse-reflectance FTIR-spectroscopy using such probe molecules as CO, CD(3)CN and CDCl(3) to test low-coordinated metal ions. At low temperatures of decomposition of complexes (up to 400°C), low-coordinated Co(3+) ions predominate in the LaCoO(x) nanoparticles, whereas basically Co(2+) ions are found upon increasing the decomposition temperature to 600°C. The novel nano-sized perovskite catalysts exhibit a very high catalytic activity in the abatement of volatile organic compounds present in air, like methanol and light hydrocarbons. 相似文献
127.
Result-oriented approaches to the management of drinking water catchments in agricultural landscapes
Alexander Wezel Maria Zipfer Christine Aubry Fabienne Barataud Alois Heißenhuber 《Journal of Environmental Planning and Management》2016,59(2):183-202
Management of water quality in drinking water catchments is of ongoing, high importance as nitrate concentrations are often still very high. We analysed the Augsburg catchment in Germany, a unique example where a result-oriented approach has been implemented. We investigated the historical evolution of the water protection programme, the result-oriented payment contracts with farmers, and farmer satisfaction with the contracts, based on interviews with the water utility and farmers as well as an analysis of the literature. Today, the water protection programme has been successfully implemented, and a significant reduction of nitrate concentration was achieved due to the following factors: (1) investment of non-negligible amounts of money for high compensation and remuneration payments, (2) different contract options, (3) farmers’ participation in the negotiation process for result-oriented payment contracts, (4) involvement of “outside” people and institutions in negotiation processes, (5) anticipation of starting a programme when nitrate levels were still far below legislative thresholds, and (6) a political and legislative framework allowing direct decisions by a water supplier. 相似文献
128.
While methodological choices are critical for solution-oriented adaptation research, the current debate on these is underdeveloped and characterized by simple dichotomies such as bottom-up and top-down as well as vaguely defined concepts such as vulnerability. Adaptation challenges and approaches for addressing them are more diverse than these labels suggest. This paper addresses this deficit by developing a diagnostic framework that helps to identify approaches suitable for addressing a given adaptation challenge. The framework was developed out of the necessity to discuss diverse approaches from natural science, social science and practice in a set of adaptation case studies conducted within the European funded MEDIATION project. Based on these case studies complemented by the literature, we iteratively abstracted typical adaptation challenges researched, typical approaches taken, and empirical, theoretical and normative criteria applied for choosing a particular approach. Our results refine the methodological debate by distinguishing between the three general adaptation challenges of identifying adaptation needs, identifying adaptation measures and appraising adaptation options. Adaptation challenges are further classified according to private and public interest involved, individual or various types of collective action involved, data/model availability, decision-making time horizon, etc. For each type of challenge and approach, we give examples and discuss salient issues. Our results point to the opportunity to apply institutional and behavioural research to support the identification of measures and possibly avoiding barriers in practice. The diagnostic framework also serves as the basis for the forthcoming guidance for assessing vulnerability, impacts and adaptation to be published by the UNEP programme of research on climate change vulnerability, impacts and adaptation. 相似文献
129.
Chester W. Spicer Michael W. Holdren Kenneth A. Cowen Darrell W. Joseph Jan Satola Bradley Goodwin Howard Mayfield Alexander Laskin M. Lizabeth Alexander John V. Ortega Matthew Newburn Robert Kagann Ram Hashmonay 《Atmospheric environment (Oxford, England : 1994)》2009,43(16):2612-2622
Aircraft emissions affect air quality on scales from local to global. More than 20% of the jet fuel used in the U.S. is consumed by military aircraft, and emissions from this source are facing increasingly stringent environmental regulations, so improved methods for quickly and accurately determining emissions from existing and new engines are needed. This paper reports results of a study to advance the methods used for detailed characterization of military aircraft emissions, and provides emission factors for two aircraft: the F-15 fighter and the C-130 cargo plane. The measurements involved outdoor ground-level sampling downstream behind operational military aircraft. This permits rapid change-out of the aircraft so that engines can be tested quickly on operational aircraft. Measurements were made at throttle settings from idle to afterburner using a simple extractive probe in the dilute exhaust. Emission factors determined using this approach agree very well with those from the traditional method of extractive sampling at the exhaust exit. Emission factors are reported for CO2, CO, NO, NOx, and more than 60 hazardous and/or reactive organic gases. Particle size, mass and composition also were measured and are being reported separately. Comparison of the emissions of nine hazardous air pollutants from these two engines with emissions from nine other aircraft engines is discussed. 相似文献
130.
A soil sampling intercomparison exercise for the ALMERA network 总被引:1,自引:0,他引:1
Maria Belli Paolo de Zorzi Umberto Sansone Abduhlghani Shakhashiro Adelaide Gondin da Fonseca Alexander Trinkl Thomas Benesch 《Journal of environmental radioactivity》2009
Soil sampling and analysis for radionuclides after an accidental or routine release is a key factor for the dose calculation to members of the public, and for the establishment of possible countermeasures. The IAEA organized for selected laboratories of the ALMERA (Analytical Laboratories for the Measurement of Environmental Radioactivity) network a Soil Sampling Intercomparison Exercise (IAEA/SIE/01) with the objective of comparing soil sampling procedures used by different laboratories. The ALMERA network is a world-wide network of analytical laboratories located in IAEA member states capable of providing reliable and timely analysis of environmental samples in the event of an accidental or intentional release of radioactivity. Ten ALMERA laboratories were selected to participate in the sampling exercise. The soil sampling intercomparison exercise took place in November 2005 in an agricultural area qualified as a “reference site”, aimed at assessing the uncertainties associated with soil sampling in agricultural, semi-natural, urban and contaminated environments and suitable for performing sampling intercomparison. In this paper, the laboratories sampling performance were evaluated. 相似文献