Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of... 相似文献
Poly(butylene succinate) (PBS) was melt blended with glycerol based polyesters (PGS) synthesized from pure and technical glycerol aiming to improve the impact strength of PBS. It was found that after addition of 30 wt% PGS to PBS its impact strength was significantly increased by 344% (from 31.9 to 110 J/m) and its elongation at break was maintained at 220%. Infrared spectra of the blends showed the presence of hydroxyl groups from the PGS phase suggesting that hydrogen bonding between the phases could be responsible for a good stress transfer and an efficient toughening in the PBS/PGS blends. Scanning electron microscopy imaging showed a good dispersion of PGS phase into PBS with a PGS particle size of 10 μm and less and no agglomeration. Addition of PGS to PBS was shown to be an effective strategy for improvement of PBS impact resistance without serious detrimental effects on its thermal and rheological properties. 相似文献
The degree of individual or gender variation when exploiting food resources is an important aspect in the study of foraging
ecology within a population. Previous information on non-breeding skimmers obtained through conventional methodologies suggested
sex-related differences in prey species. In this study, stable isotope techniques were used to investigate the intraspecific
segregation in diet and foraging habits of the Black Skimmer (Rynchops niger intercedens) at Mar Chiquita Coastal Lagoon (37°40′S, 57°22′W), Argentina. These results were compared with contemporary data on the
trophic composition obtained by conventional methodologies. Blood samples were taken from birds captured with mist-nets during
their non-breeding season. The isotopic signatures of skimmers showed a diet mainly composed of marine prey with some degree
of estuarine fish intake. When comparing diet between sexes, males showed enrichment in 15N compared to females, while no differences were observed in 13C. The use of mixing models revealed differences in the relative composition of prey in the diet of male and female skimmers.
This study highlights stable isotope analysis as a valuable tool to test inter-individual differences and sexual segregation
in trophic ecology of Black Skimmers as compared to conventional methodologies. The results show a trophic segregation in
the Black Skimmer during the non-breeding season that can be explained by differences in prey species and larger prey sizes
of male skimmers. Our findings have significant implications for conservation since any environmental change occurring at
wintering areas might have profound effects on several avian life-history traits, and could be different for males and females
due to trophic segregation. 相似文献
This text describes two different experiences of co-operation between unionists and researchers that resulted in writing of a book. We emphasize their similarities and differences and discuss the importance of these experiences in the dynamics of research and training in Ergonomics. 相似文献
To evaluate the possible influence of air pollutants on the incidence of respiratory tract neoplasm we studied 12 S?o Paulo City districts where air pollution is observed. We collected data on pollutants from 1981-1990 and correlated it with the incidence of larynx and lung neoplasms in 1997. Ozone was the pollutant that best correlated with the incidence of neoplasm. The correlation coefficients were 0.7234 (p=0.277) and 0.9929 (p=0.007) for lung and larynx cancer, respectively. There may be a relationship between air pollution and the incidence of respiratory tract neoplasm. This study, however, does not allow us to conclude that there is a causal relationship. 相似文献
The Framework Directive (FWD) and the proposed Daughter Directives are the newest legislative instruments concerning a new political strategy and air quality management approach for Europe. Additionally, the member countries of the United Nations Economic Commission for Europe have included the concepts of critical load and level for planning air pollution abatement strategies and as a base of international agreements concerning limitation of the emissions of air pollutants. These concepts imply an accurate knowledge about pollutants deposition fluxes. The paper describes the main needs and the tools available to define a strategy of air quality management in Portugal. Two study cases are presented: (1) extensive monitoring plan to assess the impact of an urban incinerator plant; and (2) contribution to a methodology to estimate critical levels for a coastal region in Portugal. These different approaches allowed illustrating the complexity of the implementation of an air pollution management strategy. 相似文献
The accumulation of heavy metals in the environment may have a wide range of health effects on animals and humans. Thus, in this study, the concentrations of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in the blood and tissues (liver and kidney) of Portuguese common buzzards (Buteo buteo) were determined by inductively coupled plasma-mass spectrometer (ICP-MS) in order to monitor environmental pollution to these elements. In general, Hg and As were the elements which appeared in the highest and lowest concentrations, respectively. A highest percentage of non-detected concentration was found for blood Cd (94.6 %) but, in turn, it was the only metal that was detected in all kidney samples. The kidney was the analyzed sample which showed the highest concentrations of each element evaluated. Statistically, significant differences among blood, liver, and kidney samples were observed for As and Cd (P?0.05). Cd concentrations in kidney and liver varied significantly with age: Adults showed higher hepatic and renal Cd concentrations than juveniles. Blood Pb concentration seems to show an association with the hunting season. Although raptors are at the top of the food chain and are thus potentially exposed to any biomagnification processes that may occur in a food web, the individuals evaluated in this study generally had low levels of heavy metals in blood and tissues. However, chronic exposure to these metals was verified. The results presented here lend weight to arguments in favor of continuous biomonitoring of metals and metalloids, since heavy metals may accumulate to levels that will pose a risk to both human health and the environment. 相似文献
Human-induced urban growth and sprawl have implications for greenhouse gas (GHG) emissions that may not be included in conventional GHG accounting methods. Improved understanding of this issue requires use of interactive, spatial-explicit social–ecological systems modeling. This paper develops a comprehensive approach to modeling GHG emissions from urban developments, considering Stockholm County, Sweden as a case study. GHG projections to 2040 with a social–ecological system model yield overall greater emissions than simple extrapolations in official climate action planning. The most pronounced difference in emissions (39% higher) from energy use single-residence buildings resulting from urban sprawl. And this difference is not accounted for in the simple extrapolations. Scenario results indicate that a zoning policy, restricting urban development in certain areas, can mitigate 72% of the total emission effects of the model-projected urban sprawl. The study outcomes include a decision support interface for communicating results and policy implications with policymakers.