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101.
Whether the radial thickness (RT) of the chloragogenous tissue and intestinal epithelium of earthworms (Lumbricus terrestris) reflects the bioavailability of metals in soils was investigated in two areas, one with active volcanism (Furnas) and another with no volcanic activity since 3 million years ago (Santa Maria), in the Azores. Metal contents in soil samples and earthworms from the two areas were analyzed. Autometallography and measurements of the RT were performed in the chloragogenous tissue and intestinal epithelium. Earthworms from the active volcanic area demonstrated lower RT of chloragogenous tissue and intestinal epithelium as well as higher levels of bioavailable metals, especially Zn and Cd. Comparison of bioavailable metal contents between both areas suggests a higher risk for uptake of potentially toxic metals in the active volcanic area than in the non-active volcanic area, which is reflected by the lower RT of the chloragogenous tissue and intestinal epithelium in the former.  相似文献   
102.
The biodegradability of poly--hydroxybutyrate and poly--caprolactone in soil compostage before and after irradiation of the polymers for 192, 425, and 600 h in a Weather-Ometer was examined. The biodegradability tests were done in soil compostage at pH 7.0, 9.0, and 11.0 to assess the influence of this parameter on degradation. The rate of degradation was directly proportional to the soil alkalinity. Poly--hydroxybutyrate showed the greatest weight loss and aging in a Weather-Ometer did not significantly increase the biodegradation, except when the polymer was aged for 425 h and buried in soil compostage of pH 11.0.  相似文献   
103.
Environment, Development and Sustainability - The objective of this work was to analyse the relations between innovation management and organisational sustainability in a Brazilian higher education...  相似文献   
104.
Conspicuousness of courtship signals in animals likely evolved to maximize mate attraction while minimizing predator detection. It is assumed, though largely unknown, that environmental and luminosity conditions affect the detectability of ornaments and motor displays and could thus strongly influence behavior. We combined visual models and behavioral observations to test whether the multimodal display of the blue-black grassquit (Volatinia jacarina) is influenced by environmental conditions, predicting that males should display more often in moments with high sunlight incidence upon their bodies. By displaying in such a context-dependent fashion, males would be able to maximize conspicuousness of their iridescent blue-black plumage and avoid displaying continuously, since the latter would involve higher energetic investment. We recorded the rates of both complete displays (leap with singing) as well as incomplete ones (singing while perched) for males during repeated 30-min focal observations in varying environmental situations in the field. We found that when bathed directly in sunlight, males increased their rates of displays, tending to exhibit more complete rather than incomplete displays in this condition and suggesting a potential trade-off between display types. Our results suggest that animals may adjust the timing and precise location of signal activity to improve the efficiency or likelihood of detection of some signal elements.  相似文献   
105.
Iron electrodes were used for electrocoagulation (EC) treatment of wastewater from a dairy plant. Electrolysis time, pH, current density and distance between electrodes were considered to assess the removal efficiency of chemical oxygen demand (COD), total solids (TS) and their fractions and turbidity. Samples were collected from the effluent of a dairy plant using a sampling methodology proportional to the flow. The treatments were applied according to design factorial of half fraction with two levels of treatments and three repetitions at the central point. The optimization of parameters for treating dairy industry effluent by electrocoagulation using iron electrodes showed that electric current application for 15 minutes, an initial sample pH close to neutral (pH 7.0) and a current density of 50 A (.)(m-2) resulted in a significant reduction in COD by 58 %; removal of turbidity, suspended solids and volatile suspended solids by 95 %; and a final treated effluent pH of approximately 9.5. Negative consequences of the type of electrode used were the emergence of an undesirable color and an increase in the proportion of dissolved solids in the treated effluent.  相似文献   
106.
Prosopis juliflora, which is an alien tree species in Ethiopia, has invaded over 360,500 ha of land in the Afar region of the country and is threatening pastoral livelihoods. We conducted a contingent valuation study to assess rural households’ willingness to contribute in cash and labor to mitigate P. juliflora invasion in three districts of Afar. Results show that about 84% of the respondents prefer an intervention involving complete eradication of P. juliflora. The lower and upper bound median willingness to contribute to this intervention were 9.97 and 13.42 USD/household/year in cash and 30 and 43 days/household/year in labor. Off-farm income and P. juliflora invasion levels on pasturelands are among the factors affecting willingness to contribute to the mitigation of P. juliflora invasion. Incentives to local people and having a proper institutional setup that involves local culture and institutions are important for mobilizing people on a voluntary basis for mitigation of P. juliflora invasion.  相似文献   
107.
108.
Open-top chambers (OTCs) were used to evaluate the effects of moderately elevated O3 (40-50 ppb) and CO2 (+100 ppm) and their combination on N2O, CH4 and CO2 fluxes from ground-planted meadow mesocosms. Bimonthly measurements in 2002-2004 showed that the daily fluxes of N2O, CH4 and CO2 reacted mainly to elevated O3, while the fluxes of CO2 also responded to elevated CO2. However, the fluxes did not show any marked response when elevated O3 and CO2 were combined. N2O and CO2 emissions were best explained by soil water content and air and soil temperatures, and they were not clearly associated with potential nitrification and denitrification. Our results suggest that the increasing O3 and/or CO2 concentrations may affect the N2O, CH4 and CO2 fluxes from the soil, but longer study periods are needed to verify the actual consequences of climate change for greenhouse gas emissions.  相似文献   
109.
This work presents a liquid disposal monitoring originated from uranium enrichment process at Aramar Experimental Center from 1990 to 1998. Assessment of uranium, fluorides, ammoniacal nitrogen, chemical oxygen demand, and pH measurements were made in water samples and compared with results achieved in other countries, as North America and India. The liquid disposal evaluation, generated by uranium enrichment process, showed low levels, considering most parameters established by Federal and State Legislation, aiming environmental pollution control. However, uranium levels were above the limits established by Conselho Nacional do Meio Ambiente, Environment Protection Agency and mainly by the World Health Organization.  相似文献   
110.
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