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331.
Aromatase activity was determined in brain and gonads of wild bream collected along the river Elbe, Germany, and correlated with other endocrine and reproductive endpoints such as plasma sex steroid concentrations, secondary sex characteristics (STI), plasma vitellogenin, gonad size (GSI), and maturation stages of germ cells (MS) that were reported for the same fish in a previous study. Furthermore, regional patterns of aromatase activity were correlated to a number of environmental factors such as exposure to environmental contaminants and parasitism. While aromatase activity was not detectable in the gonads of male and female fish with the assay used, fish of both genders revealed relatively great brain enzyme activities. As for most of the endocrine and reproductive parameters, with the exception of plasma testosterone (T), aromatase activities were significantly less in fish from a river stretch characterized by elevated exposures to organic contaminants and metals. Brain aromatase activity was positively and significantly correlated with plasma estradiol (E2) and MS in females, and showed a similar trend with plasma 11-ketotestosterone (11KT) and STI in males. No comparable trend occurred for T. This decrease of the reproductively relevant hormones 11KT and E2 may be indicative of a disruption of the last step in sex hormone synthesis, a hypothesis that was supported for E2 by the strong (R2=0.78, p<0.05) linear regression between aromatase activity and E2 in female bream. It is also hypothesized that the effects on brain aromatase activity were likely to be related to the disruption of other reproductive parameters including sexual maturity and expression of secondary sex characteristics. Although a number of factors such as exposure to pollutants and prevalence of the tapeworm Ligula intestinalis correlated with the suppression of aromatase activity, the exact causes for the regional decrease in brain aromatase activity remain unclear due to inconsistencies of these correlations between sampling events or gender.  相似文献   
332.
Ochsenbein U  Zeh M  Berset JD 《Chemosphere》2008,72(6):974-980
Off-line solid phase extraction and direct injection analysis were evaluated for the determination of traces of explosives such as TNT and its mono and diamino metabolites, HMX, RDX, nitroglycerin and PETN in lake water and tributaries applying liquid chromatography-electrospray tandem mass spectrometry. Improved chromatographic separation was achieved on a phenyl based stationary phase with baseline resolution of the mono- and diamino metabolites of TNT. Identification and quantification of the target compounds was performed by multiple reaction monitoring applying electrospray ionization in either the positive mode for the diaminometabolites of TNT or the negative mode for all other compounds. An extensive method validation was performed and limits of quantification were obtained for the explosives in preconcentrated lake water samples from 0.03 to 1 ng l(-1) and 0.1 to 5 ng l(-1) in river water. Direct injection analysis revealed comparable results to preconcentrated water samples for the most persistent explosives. Analysis of lake water samples collected at different depths showed the presence of HMX, RDX and PETN at concentrations from 0.1 to 0.4 ng l(-1). The analysis of main tributaries revealed concentrations from 0.1 to 0.9 ng l(-1) of the same compounds. They seem to be responsible for the contamination of the explosives in the lakes.  相似文献   
333.
Usnic acid controls the acidity tolerance of lichens   总被引:2,自引:0,他引:2  
The hypotheses were tested that, firstly, lichens producing the dibenzofuran usnic acid colonize substrates characterized by specific pH ranges, secondly, this preferred pH is in a range where soluble usnic acid and its corresponding anion occur in similar concentrations, and thirdly, usnic acid makes lichens vulnerable to acidity. Lichens with usnic acid prefer an ambient pH range between 3.5 and 5.5 with an optimum between 4.0 and 4.5. This optimum is close to the pKa1 value of usnic acid of 4.4. Below this optimum pH, dissolved SO2 reduces the chlorophyll fluorescence yield more in lichens with than without their natural content of usnic acid. This suggests that usnic acid influences the acidity tolerance of lichens. The putative mechanism of the limited acidity tolerance of usnic acid-containing lichens is the acidification of the cytosol by molecules of protonated usnic acid shuttling protons through the plasma membrane at an apoplastic pH < pKa1.  相似文献   
334.
The disposal of coal combustion residues (CCR) has led to a significant consumption of land in the West Balkan region. In Tuzla (Bosnia and Herzegovina) we studied previously soil-covered (farmed) and barren CCR landfills including management practises, field ageing of CCR and the transfer of trace elements into crops, wild plants and wastewaters. Soil tillage resulted in mixing of cover soil with CCR. Medicago sativa showed very low Cu:Mo ratios (1.25) which may cause hypocuprosis in ruminants. Total loads of inorganic pollutants in the CCR transport water, but not pH ( approximately 12), were below regulatory limits of most EU countries. Arsenic concentrations in CCR transport water were <2microgl(-1) whereas reductive conditions in an abandoned landfill significantly enhanced concentrations in leachates (44microgl(-1)). The opposite pattern was found for Cr likely due to large initial leaching of CrVI. Public use of landfills, including farming, should be based on a prior risk assessment due to the heterogeneity of CCR.  相似文献   
335.
Air pollution is increasingly recognized as a significant contributor to global health outcomes. A methodological framework for evaluating the global health-related outcomes of outdoor and indoor (household) air pollution is presented and validated for the year 2005. Ambient concentrations of PM2.5 are estimated with a combination of energy and atmospheric models, with detailed representation of urban and rural spatial exposures. Populations dependent on solid fuels are established with household survey data. Health impacts for outdoor and household air pollution are independently calculated using the fractions of disease that can be attributed to ambient air pollution exposure and solid fuel use. Estimated ambient pollution concentrations indicate that more than 80% of the population exceeds the WHO Air Quality Guidelines in 2005. In addition, 3.26?billion people were found to use solid fuel for cooking in three regions of Sub Saharan Africa, South Asia and Pacific Asia in 2005. Outdoor air pollution results in 2.7?million deaths or 23?million disability adjusted life years (DALYs) while household air pollution from solid fuel use and related indoor smoke results in 2.1?million deaths or 41.6?million DALYs. The higher morbidity from household air pollution can be attributed to children below the age of 5 in Sub Saharan Africa and South Asia. The burden of disease from air pollution is found to be significant, thus indicating the importance of policy interventions.  相似文献   
336.
Manado is the largest and most densely populated coastal city in North Sulawesi Province, Indonesia. The city is facing problems of wastewater discharged from various sources. These problems are driven by high population pressure, increasing economic activity, and low household income, in combination with inadequate organizational structure of government institutions for addressing the wastewater problems as well as for law enforcement. There have been no community initiatives to prevent or mitigate wastewater problems. Therefore, a wastewater management plan is urgently needed to prevent and mitigate pollution caused by discharged wastewater. In this paper we analyze the current situation with respect to environmental state, sources and treatment of wastewater, socio-economic and institutional capacities as well as community awareness. Constraints and potentials are discussed to give recommendations for an integrated wastewater management plan for the city of Manado.  相似文献   
337.
The aim of our article is to follow how global policy models affect local policy making. Each city has unique local challenges in promoting development, e.g. economic growth, but also needs to find a balance between these targets and demands for sustainable city solutions. In our empirical study, we follow how ideas of waterfront development – to attract new inhabitants and promote economic growth – and global demands of carbon control were used interactively in a strategic spatial planning process in the city of Tampere, Finland. During the six-year planning process, these two policy targets became interdependent, created a new policy-making domain, and led to a combinatorial development of sustainability elements arising from this domain. These findings demonstrate the serial use of global policy models in the creation of a local urban ‘sustainability fix’. To conclude, the intertwinement of diverse global policy models in a city planning process creates easily a recursive cycle that redefines urban sustainability within cities and intercity networks. This perspective makes local policy narratives and strategic planning highly important in urban sustainability research as promoting urban sustainability becomes an inherently ambivalent practice.  相似文献   
338.
The present study focuses on developing models to predict lichen species richness in a UNESCO Biosphere Reserve of the Swiss Pre-Alps following a gradient of land-use intensity combining remote sensing data and regression models. The predictive power of the models and the obtained r ranging from 0.5 for lichens on soil to 0.8 for lichens on trees can be regarded as satisfactory to good, respectively. The study revealed that a combination of airborne and spaceborne remote sensing data produced a variety of ecological meaningful variables.  相似文献   
339.
We describe the application of quantitative evaluation of mineralogy by scanning electron microscopy in combination with techniques commonly available at hard X-ray microprobes to define the mineralogical environment of a bauxite residue core segment with the more specific aim of determining the speciation of trace metals (e.g., Ti, V, Cr, and Mn) within the mineral matrix. Successful trace metal speciation in heterogeneous matrices, such as those encountered in soils or mineral residues, relies on a combination of techniques including spectroscopy, microscopy, diffraction, and wet chemical and physical experiments. Of substantial interest is the ability to define the mineralogy of a sample to infer redox behavior, pH buffering, and mineral-water interfaces that are likely to interact with trace metals through adsorption, coprecipitation, dissolution, or electron transfer reactions. Quantitative evaluation of mineralogy by scanning electron microscopy coupled with micro-focused X-ray diffraction, micro-X-ray fluorescence, and micro-X-ray absorption near edge structure (mXANES) spectroscopy provided detailed insights into the composition of mineral assemblages and their effect on trace metal speciation during this investigation. In the sample investigated, titanium occurs as poorly ordered ilmenite, as rutile, and is substituted in iron oxides. Manganese's spatial correlation to Ti is closely linked to ilmenite, where it appears to substitute for Fe and Ti in the ilmenite structure based on its mXANES signature. Vanadium is associated with ilmenite and goethite but always assumes the +4 oxidation state, whereas chromium is predominantly in the +3 oxidation state and solely associated with iron oxides (goethite and hematite) and appears to substitute for Fe in the goethite structure.  相似文献   
340.
The use of genetically modified plants in agriculture (GM crops) is controversially discussed in academic publications. Important issues are whether the release of GM crops is beneficial or harmful for the environment and therefore acceptable, and whether the modification of plants is ethically permissible per se. This study provides a comprehensive overview of the moral reasoning on the use of GM crops expressed in academic publications from 1975 to 2008. Environmental ethical aspects in the publications were investigated. Overall, 113 articles from 15 ecology, environmental ethics, and multidisciplinary science journals were systematically reviewed. Three types of moral concerns were used to structure the normative statements, moral notions, and moral issues found in the articles: concerns addressing consequences of the use of GM crops, concerns addressing the act (the technique itself), and concerns addressing the virtues of an actor. Articles addressing consequences (84%) dealt with general ecological and risk concerns or discussed specific ecological issues about the use of GM crops. Articles addressing the act (57%) dealt with the value of naturalness, the value of biotic entities, and conceptual reductionism, whereas articles addressing the actor (43%) dealt with virtues related to the handling of risks and the application of GM crops. The results of this study may help to structure the academic debate and contribute to a better understanding of moral concerns that are associated with the key aspects of the ethical theories of consequentialism, deontology, and virtue ethics.  相似文献   
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