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341.
This study was aimed at evaluating the effects of gasoline-ethanol blends on the exhaust emissions in a catalyst-equipped four-stroke moped engine. The ethanol was blended with unleaded gasoline in at percentages (10, 15, and 20% v/v). The regulated pollutants and the particulate matter emissions were evaluated over the European ECE R47 driving cycle on the chassis dynamometer bench. Particulate matter was characterized in terms of total mass collected on filters and total number ofparticles in the range 7 nm-10 microm measured by electrical low-pressure impactor (ELPI). In addition, particle-phase polycyclic aromatic hydrocarbons (PAHs) emissions were evaluated to assess the health impact of the emitted particulate. Finally, an accurate morphological analysis was performed on the particulate by high-resolution transmission electron microscope (TEM) equipped with a digital image-processing/data-acquisition system. In general, CO emission reductions of 60-70% were obtained with 15 and 20% v/v ethanol blends, while the ethanol use did not reduce hydrocarbon (HC) and NOx emissions. No evident effect of ethanol on the particulate mass emissions and associated PAHs emissions was observed. Twenty-one PAHs were quantified in the particulate phase with emissions ranging from 26 to 35 microg/km and benzo[a]pyrene equivalent (BaPeq) emission factors from 2.2 to 4.1 microg/km. Both particulate matter and associated PAHs with higher carcinogenic risk were mainly emitted in the submicrometer size range (<0.1 microm). On the basis of the TEM observations, no relevant effect of the ethanol use on the particulate morphology was evidenced, showing aggregates composed ofprimary particles with mean diameters in the range 17.5-32.5 nm.  相似文献   
342.
Potentials for the prevention of municipal solid waste   总被引:1,自引:0,他引:1  
Waste prevention has been assigned the highest priority under European waste management law. However, the initiatives which have been taken so far have not reduced the regular annual increase in total waste arising across Europe. The purpose of this paper is to quantify and analyze in depth the prevention potential for selected case studies (advertising material, beverage packaging, diapers, food waste, waste from events). Only such measures are considered, which do not require a reduction of consumption. The prevention potentials for household waste in theory are exemplified for the city of Vienna, also with a view to barriers that may reduce the achievable prevention potential. The results show that the prevention potentials for the analyzed individual measures can reach an order of magnitude of some 10% of the relevant waste stream (e.g., advertising material, beverage packaging), or rather 1-3% of municipal solid waste. The prevention potentials appear to be relatively small in relation to the total municipal waste quantities. Methodological shortcomings, such as the missing availability of basic data, make it difficult to exactly estimate the impact of waste prevention measures on waste quantities, which is only one of the effects of waste prevention among other ecological, social and economic aspects.  相似文献   
343.
Synergistic combinations of climatic and land use changes have the potential to produce the most dramatic impacts on land cover. Although this is widely accepted, empirical examples, particularly involving deforestation in Latin America, are still very few. The geographic extent and causes of deforestation in subtropical seasonally dry forests of the world have received very little attention. This is especially true for the Chaco forests in South America, which are being lost at an alarming rate, sometimes higher than those reported for tropical forests. On this basis, the aims of this study were to analyze the changes in land cover that have occurred during the last three decades of the 20th century in the Chaco forests of central Argentina, and to explain the factors that have driven those changes. Results show major land cover changes. Approximately 80% of the area that was originally undisturbed forest is now occupied by crops, pastures, and secondary scrub. The main proximate cause of deforestation has been agricultural expansion, soybean cultivation in particular. This appears as the result of the synergistic convergence of climatic, technological, and socioeconomic factors, supporting the hypothesis of a multiple-factor explanation for forest loss, while providing one of the very few existing analyses of changes in subtropical forests of the world.  相似文献   
344.
Compost and digestate are important recycling fertilizers and have beneficial effects on soil parameters. However, they can contain significant amounts of organic pollutants. Here, the first comprehensive data set on dibenzo-p-dioxins and -furans (PCDD/F), dioxin-like polychlorinated biphenyls (DL-PCB), brominated flame retardants, perfluorinated alkyl substances (PFAS), pesticides, phthalates, nonylphenol and chlorinated paraffins (CP) in source-separated compost and digestate from Switzerland is presented (n = 3-18). The median summation 17PCDD/F and summation 12DL-PCB concentrations were at 3.2 ng I-TEQ kg(-1)dry weight (dw) and 3.0 ng WHO-TEQ kg(-1)dw, respectively. Brominated diphenyl ether 209 (BDE 209) accounted for 72% of the total polyBDE content (10 microg kg(-1)dw). Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) levels were at 100 and 0.51 microg kg(-1)dw, respectively. PFAS were identified for the first time in compost and digestate (median concentration 6.3 microg kg(-1)dw, summation 21compounds). Out of 269 pesticides analysed, 30 fungicides, 14 herbicides, eight insecticides and one acaricide were detected. Di-(2-ethylhexyl)phthalate (DEHP) median concentration accounted for 280 microg kg(-1)dw and nonylphenol was below the detection limit of 1 mg kg(-1)dw. The sum of short and medium chain CP was between 90 and 390 microg kg(-1)dw. The concentrations observed were at or above the levels found in background soils, which are the main recipient of compost and digestate. Where actually applied, compost can contribute considerably to the total input of organic pollutants to the soil. However, on a total Swiss agricultural area base, inputs seem to be limited.  相似文献   
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Phylogenetic analysis of extinction threat is an emerging tool in the field of conservation. However, there are problems with the methods and data as commonly used. Phylogenetic sampling usually extends to the level of family or genus, but International Union for Conservation of Nature (IUCN) rankings are available only for individual species, and, although different species within a taxonomic group may have the same IUCN rank, the species may have been ranked as such for different reasons. Therefore, IUCN rank may not reflect evolutionary history and thus may not be appropriate for use in a phylogenetic context. To be used appropriately, threat‐risk data should reflect the cause of extinction threat rather than the IUCN threat ranking. In a case study of the toad genus Incilius, with phylogenetic sampling at the species level (so that the resolution of the phylogeny matches character data from the IUCN Red List), we analyzed causes of decline and IUCN threat rankings by calculating metrics of phylogenetic signal (such as Fritz and Purvis’ D). We also analyzed the extent to which cause of decline and threat ranking overlap by calculating phylogenetic correlation between these 2 types of character data. Incilius species varied greatly in both threat ranking and cause of decline; this variability would be lost at a coarser taxonomic resolution. We found far more phylogenetic signal, likely correlated with evolutionary history, for causes of decline than for IUCN threat ranking. Individual causes of decline and IUCN threat rankings were largely uncorrelated on the phylogeny. Our results demonstrate the importance of character selection and taxonomic resolution when extinction threat is analyzed in a phylogenetic context.  相似文献   
348.
In our introduction to this special issue, we explain why understanding the social and situational context around workplace mistreatment is important. We then provide summaries of the six articles in this special issue and conclude by identifying three key themes—social interpretation, recursive nature of mistreatment, and beyond the dyad—and some important directions for future research.  相似文献   
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Human–wildlife conflicts are commonly addressed by excluding, relocating, or lethally controlling animals with the goal of preserving public health and safety, protecting property, or conserving other valued wildlife. However, declining wildlife populations, a lack of efficacy of control methods in achieving desired outcomes, and changes in how people value animals have triggered widespread acknowledgment of the need for ethical and evidence‐based approaches to managing such conflicts. We explored international perspectives on and experiences with human–wildlife conflicts to develop principles for ethical wildlife control. A diverse panel of 20 experts convened at a 2‐day workshop and developed the principles through a facilitated engagement process and discussion. They determined that efforts to control wildlife should begin wherever possible by altering the human practices that cause human–wildlife conflict and by developing a culture of coexistence; be justified by evidence that significant harms are being caused to people, property, livelihoods, ecosystems, and/or other animals; have measurable outcome‐based objectives that are clear, achievable, monitored, and adaptive; predictably minimize animal welfare harms to the fewest number of animals; be informed by community values as well as scientific, technical, and practical information; be integrated into plans for systematic long‐term management; and be based on the specifics of the situation rather than negative labels (pest, overabundant) applied to the target species. We recommend that these principles guide development of international, national, and local standards and control decisions and implementation.  相似文献   
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