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121.
Journal of Polymers and the Environment - Biodegradability is a key feature for the application of polymeric devices in medicine. This study reports an experimental and theoretical study of the...  相似文献   
122.
The relationships between macrobenthic subtidal community structure and the status of sediment pollution were analysed at 24 sampling stations in the Montevideo coastal zone. In order to judge the status of community perturbation a phylum-level meta-analysis was applied to the production data from the Montevideo coastal zone samples alone and combined with the original training data set from 50 samples collected on the NE European shelf. The community was dominated by the gastropod Heleobia cf. australis. The MDS (multi-dimensional scaling) ordination with abundance data (species-level) and the MDS ordination with production data (phylum level), using only our samples, showed the formation of three groups of stations. Results of the BIO-ENV procedure showed that lead, salinity and polycyclic aromatic hydrocarbons (PAHs) were the variables that best explained the biological pattern observed. However, a clear salinity gradient was observed from the inner stations of Montevideo Bay to the outer coastal stations; the high levels of Pb, PAH and Cr concentrations recorded at stations B, C and D in Montevideo Bay were important in discriminating these locations from the others. The MDS ordination combining the production data from the 24 samples from the Montevideo coastal zone with the original data set showed correct assessment of the pollution status for the 24 samples from Montevideo on a common scale of perturbation. The separation of the Montevideo coastal zone samples seems to be mainly due to the high proportion of molluscs. Our results suggest general applicability of the phylum-level meta-analysis approach, even in such cases as this, with high dominance of only one phylum; however, more studies are still necessary.Communicated by O. Kinne, Oldendorf/Luhe  相似文献   
123.
Wastes with residual heating value, according to the trend of the world legislation, could be thermally reused. The present study is conducted to verify the possibility of thermal valorisation of a waste, denominated fluff, by injection in blast furnace. The fluff, arising from the automobile shredder operations, is a waste characterised by a high organic matrix and is potentially dangerous due to the heavy metals, oils filter and halogenated plastics content. The first step of the work is the chemical, physical and toxicological characterisation of this material. Then the fluff injection in a blast furnace tuyere is theoretically analysed with a mathematical model. Finally, experimental trials are conducted in a pilot plant, simulating the most important part of the blast furnace: the raceway, in order to analyse process and industrial aspects. In view of an industrial application a first economical evaluation is carried out on the basis of model and experimental results.  相似文献   
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In avian species, maternal provisioning to the eggs is predicted to be more valuable for the offspring under adverse environmental conditions and intense sibling competition. However, studies manipulating both the amount of maternal pre-hatching resources and the harshness of post-hatching environment have seldom been performed to date. In this experimental study of Barn Swallow (Hirundo rustica) nestlings, we tested the consequences of a reduction in the albumen content of the eggs for fitness-related offspring traits, while performing an unbalanced partial cross-fostering soon after hatching, either increasing or decreasing brood size by one nestling. By molecular sexing of the chicks, we additionally tested for sex-specific sensitivity of individual nestlings to experimental treatments and to sex ratio variation in nestmates. We predicted that chicks hatching from albumen-deprived eggs should suffer more than control chicks from the harsher rearing conditions of enlarged broods. However, although albumen removal depressed chick body mass, chicks hatching from control eggs did not fare better than those hatching from eggs with reduced albumen content in enlarged vs. reduced broods. Albumen removal had sex-specific effects on immunity, with males, but not females, hatching from eggs with reduced albumen content showing a lower T-cell-mediated immune response than controls, suggesting that the two sexes were differentially susceptible to resource deprivation during early ontogeny. In addition, both immune response and chick body mass at age 7 days, when maximum growth rate is attained, declined with an increasing proportion of male nestmates. The effect of brood size manipulation on chick body mass at age 12 days, when peak body mass is attained, was also found to depend on brood sex composition, in that an increase in the proportion of male nestmates depressed offspring body mass in reduced broods, while the reverse was true in enlarged broods. On the whole, these findings suggest that sex differences may exist in environmental sensitivity and patterns of resource allocation among different body functions, and that brood size variation and sex composition may affect offspring fitness-related traits.  相似文献   
127.
The coastline of the state of Rio Grande do Sul (Brazil) is used annually as a migratory route by a number of seabird species. Thirteen surveys were carried out between July 1997 and July 1998 to obtain information on the diet of Puffinus gravis, Puffinus griseus, and Puffinus puffinus along the coast of Rio Grande do Sul. Sampling efforts focused on dead beach-cast specimens. One hundred twenty-one stomach content analyses were performed on P. gravis from a total of 238 specimens; 17 stomach content analyses were performed on P. griseus from a total of 54 specimens; and 25 stomach content analyses were performed on 25 P. puffinus from a total of 61 dead specimens. Cephalopods were the main prey found in the stomachs of the three species and were present in 96% of the P. gravis stomachs. The following cephalopods were observed: Ommastrephidae, Gonatus antarcticus, Gonatus sp., Lycoteuthis lorigera, Lycoteuthis sp., Histioteuthis sp., Cycloteuthis sp., Loligo plei, Loligo sanpaulensis, Sepiidae, and Argonauta nodosa. The latter was the most abundant species in the three species of Puffinus. The following fish were identified from otoliths: Porichthys porosissimus, Ctenosciaena gracilicirrhus, Paralonchurus brasiliensis, Cynoscion guatucupa, and Trichiurus lepturus. There was also a high incidence of synthetic materials such as plastic, polyethylene and rubber.  相似文献   
128.
The objective of this study was to evaluate pesticide poisonings in the southern region of Brazil between years 1999 and 2014. Data were collected from the database Sinitox. Intoxications and deaths were evaluated according to the distribution by gender (female and male), age group (≤14, 15–59 and ≥60 years), area of occurrence (urban and rural), circumstance (accident, occupational and suicide attempt) and evolution of the cases over time (cure, unconfirmed cure, death and sequelae). In the evaluated period, 21,305 cases of intoxication were registered. The results show that males between the ages of 15 and 59 years are more affected; and there is a greater representativeness in the urban area. These results are related to the application of agrochemicals being carried out by individuals between 15 and 59 years of age. The great correlation of urban area possibly occurs in function of the air currents brought from the field and as a result, population has been more affected and the consumption of contaminated food. It was observed that women handling pesticides more cautiously, in this way the accidents with male gender are more frequent, however, many women use the product intentionally to provoke suicide.  相似文献   
129.
The increasing concern regarding the preservation of soil quality suggests the adoption of quality reference values as a first step in environmental monitoring actions. In this context, the objective of this study was to establish soil quality reference values for Al, Zn, Mn, Cd, Fe, Pb, Ni, Cr, and Cu and to correlate several soil properties with the occurrence of these elements in the hillslope region of Rio de Janeiro State. Sixty-two samples were collected at depths of 0–20 and 20–40 cm and analyzed using the USEPA method 3051A. After clustering analysis, the samples were separated into three groups. Classification functions were obtained based on the variables pH - Mg - Fe - Mn, i.e., the variables that were best related to heavy metal content. We determined to establish the quality reference values for the 75th percentile of the three groups. The relief forms of the area, which facilitate the transport of soil fine-particle fractions and accumulation in lowlands, were revealed to be one of most important factors in understanding the distribution of soil heavy metals.  相似文献   
130.
Objective: Although most research on drugs and driving has focused on the use of alcohol and cannabis, research that has been conducted on cigarette smoking and collisions has found that smokers have an increased collision involvement. Studies dating from 1967 through 2013 have shown a crude relative risk of about 1.5 among smokers compared to nonsmokers. In Canada, the association between smoking and collisions has not been recently investigated. Studies that have examined the association between smoking and collisions often did not control for all confounding factors, such as alcohol use and driving exposure, which have been associated with increased collision rates. Additionally, a number of these studies were examined in countries and at times when prevalence of smoking was much higher than is currently the case in Canada. The purpose of this research is to examine the association between self-reported current smoking and past-year collision involvement, controlling for confounding factors, in a large representative sample of adult drivers in Ontario, Canada, from 2002 and 2014.

Method: Data are based on the Centre for Addiction and Mental Health (CAMH) Monitor, an ongoing, rolling telephone survey of Ontario adults that provides epidemiological surveillance of indicators related to alcohol, tobacco, and other drug use, as well as physical and mental health. The survey uses random-digit-dialing methods via Computer-Assisted Telephone Interview, with response rates over 50%.

Results: Prevalence of self-reported collision involvement within the past year for 2002–2014 was 8.6% among those who currently smoke compared to 6.5% of nonsmokers. Logistic regression analysis, controlling for the potential confounding effects of sociodemographics, driving exposure measures, drinking frequency, and hazardous alcohol use, found that the overall odds for collision involvement in the preceding year among current smokers for 2002–2014 was 1.27 (95% confidence interval [CI], 1.06–1.53) times that of nonsmokers.

Conclusions: These findings indicate that despite a substantial reduction in overall prevalence of smoking in Canada, smokers still have a significantly increased odds of collision involvement, even when controlling for alcohol and exposure. Additionally, the results are consistent with the increased odds/risks of motor vehicle collisions found in other countries.  相似文献   

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