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1.
Abstract: The cedar oak forest of the Middle Atlas in Morocco is not only the last of the large forests in the southern Mediterranean, but it also contains all the surviving forest biodiversity. This forest has been severely affected by drought, overgrazing by mixed herds of goat and sheep, and excessive logging for timber, firewood, and livestock fodder. Recently, cedar bark stripping by Barbary Macaques (    Macaca sylvanus ) has begun to have an effect on the forest. We investigated this behavior by monitoring a 500-km2 mosaic forest of cedar and oak in the Middle Atlas of Morocco between 1994 and 1996. We surveyed the forest 18 times in four different seasons along a 90-km transect. We recorded observations of bark stripping and a variety of quantitative ecological factors that could predict this behavior, such as livestock density, forest quality, undergrowth condition, water availability, and monkey density. The statistical analysis (including rank correlation, regression, and nonparametric variance analysis) strongly suggests that water scarcity and monkey exclusion from previously available permanent water sources are correlated with intense cedar bark-stripping behavior by macaques. The density of cedars and of monkeys appeared to be only secondary factors. As a conservation policy, making water more accessible to wild monkeys might reduce bark-stripping behavior.  相似文献   
2.
The incidence of testicular cancer (TC) has been increasing worldwide during the last decades. The reasons of the increase remains unknown, but recent findings suggest that organochlorine pesticides (OPs) could influence the development of TC. A hospital-based case-control study of 50 cases and 48 controls was conducted to determine whether environmental exposure to OPs is associated with the risk of TC, and by measuring serum concentrations of OPs, including p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) isomer and hexachlorobenzene (HCB) in participants. A significant association was observed between TC and household insecticide use (odds ratio [OR] = 3.01, 95 % CI: 1.11-8.14; OR(adjusted) = 3.23, 95 % CI: 1.15-9.11). Crude and adjusted ORs for TC were also significantly associated with higher serum concentrations of total OPs (OR = 3.15, 95 % CI: 1.00-9.91; OR(adjusted) = 3.34, 95 % CI: 1.09-10.17) in cases compared with controls. These findings give additional support to the results of previous research that suggest that some environmental exposures to OPs may be implicated in the pathogenesis of TC.  相似文献   
3.
PROBLEM: After decreasing to a historic low in 1997, motorcycle crash-related fatalities are increasing. Although causes remain unclear, motorcycle rider education and licensing play key roles in reducing motorcycle crashes and injuries. Yet, little is known about what constitutes effective rider training and licensing. This study develops a model of best practices in motorcycle rider education and licensing and combines primary and secondary data to identify states that most closely adhere to this model. Evidence on the validity of the model is also examined. METHOD: States were rated along three areas of best practices: (a) program administration; (b) rider education; and (c) licensing based on 2001 data collected for a National Highway Traffic Safety Administration (NHTSA)-sponsored study. RESULTS: Results indicate wide variation in states' adherence to best practices; several states meet most, others very few. When the areas of best practices are considered separately, a state tends to behave similarly on all three. Initial evidence supports the validity of the model, with high best practices states having the lowest rates of motorcycle fatalities. IMPACT ON TRAFFIC SAFETY: As motorcycle-related crashes increase and state and federal support for rider education programs diminishes, it is critical that states identify deficiencies in their program and learn from successful states about efficient, cost-effective strategies for increasing best practices in motorcycle rider education and licensing.  相似文献   
4.
Culturable heterotrophic bacterial and phytoplanktonic densities were investigated at four sites in the Southern Adriatic Sea (Brindisi, S. Cataldo, Otranto and S. M. di Leuca) over an annual cycle. The main phytoplankton groups, the bacterial biodiversity, as well as the faecal contamination indicators were determined. Culturable bacterial numbers averaged 4.8 ± 0.2 log CFU ml−1 whereas phytoplankton numbers averaged 2.1 ± 0.4 log cells ml−1. Relationships between culturable bacteria, phytoplankton and the environmental factors were established. Bacterial and phytoplankton densities usually depended significantly on temperature, dissolved oxygen, phosphate and nitrite only in the S. Cataldo transect. In all the examined transects phytoplankton showed a bloom during the January–February period followed by a bacterial peak during the February–March period. Thus we can suppose that the phytoplankton winter bloom is responsible for the availabily of organic matter for bacterial populations in the following months in this oligotrophic ecosystem.  相似文献   
5.
In the present study the interactions between the main constituents of the refuse derived fuel (plastics, paper, and wood) during pyrolysis were studied. Binary mixtures of polyethylene-paper and polyethylene/sawdust have been transformed into pellets and pyrolyzed. Various mixtures with different composition were analyzed and pyrolysis products (tar, gas, and char) were collected. The mixtures of wood/PE and paper/PE have a different behavior. The wood/PE mixtures showed a much reduced interaction of the various compounds because the yields of pyrolysis products of the mixture can be predicted as linear combination of those of the pure components. On the contrary, a strong char yield increase was found at a low heating rate for paper/PE mixtures. In order to explain the results, the ability of wood and paper char to adsorb and convert the products of PE pyrolysis into was studied. Adsorption and desorption tests were performed on the char obtained by paper and wood by using n-hexadecane as a model compound for the heavy products of PE pyrolysis.  相似文献   
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7.
Dioxin-like PCBs (dl-PCBs) are ubiquitous persistent organic pollutants of recognized negative effects on human health. Assessing highly polluted areas should be an important public health issue. This study proposes to use the milk of grazing animals as a bioindicator of dl-PCB contamination in the environment. The hypothesis is that milk concentration of dl-PCBs are related to soil concentrations of these compounds, and that soils are generally reflective of a larger environmental issue of dl-PCB contamination. In this study, we evaluate the possibility of predicting soil concentrations using milk of sheep, cows and buffalos in a spatial model. For this purpose, samples of soil and milk collected in Campania (Italy) were introduced in a GIS platform to perform geostatistical analysis for building a simple predictive model. The ordinary least squares regressions (OLS) showed a statistically significant correlation (< 0.05) between soil and milk contamination. However, this relationship was spatially variable. Thus, a geographically weighted regression (GWR) was performed, obtaining R2 values of 0.91, 0.77 and 0.66 for sheep’s, buffalo’s and cow’s milk respectively. Assessed the mathematical relationships between the variables, new data was introduced to evaluate the performance of the model. Predictions of soil contamination with dl-PCBs using sheep’s, cow’s and buffalo’s milk showed a mean error of 23%, 25% and 36% respectively. According to these results the sheep’s milk can be considered the best bioindicator of dl-PCBs contamination among the three species. The results of this project evidence the potentialities of the proposed approach to assess bioindicator performance in a spatial predictive model.  相似文献   
8.
Food and Environmental Virology - Kinetics of hepatitis A virus (HAV) accumulation and depuration from mussels (Mytilus galloprovincialis) was studied in an experimental depuration system....  相似文献   
9.
Genetic and environmental factors influence insulin sensitivity (IS) during one's lifetime. Actually, uterine environment may affect IS at birth and later in life. In particular, various exogenous toxic substances, coupled to a genetic predisposition, may remarkably influence the regulation of the hypothalamus–hypophysis–adrenal gland axis, and the production or the activity of insulin, cerebral incretins, pro-inflammatory cytokines, and placental hormones. Owing to this reaction against environmental injuries, fetal growth and endocrine system development may be impaired, leading to low or large birth weight, or prematurity. Reduced growth in early life has been related to insulin resistance, which can be silent for years and evident in predisposed adults. The incidence of type 2 diabetes mellitus and obesity associated with sedentary lifestyle patterns and inadequate dieting behaviors in children and adolescents has rapidly increased during the last decade.Recent evidences suggest that the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-? (PPAR-?) gene and the angiotensin converting enzyme (ACE) I/D gene polymorphism combined with environmental factors, such as phthalates interfering with the post receptorial action of insulin, alter insulin-sensible tissues. Therefore, IS, deriving from a complex interaction between genotype and environment, may change during life and depends on previous metabolic control, which is a sort of metabolic memory. The goal for the future is preventing the complications associated with impaired IS through the control of exogenous factors and the use of drugs selectively effective on its pathogenesis.  相似文献   
10.
Ambient air samples were collected in five locations around a polychlorobiphenyl (PCB) production plant in a highly industrialized city in the north of Italy, for the analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) and PCBs.PCDD/F atmospheric concentrations were lower than those generally detected in urban areas, while PCB concentrations were higher than in urban and industrialized areas in other countries, especially in the locations closest to the plant. To identify source emissions responsible for air pollution we used principal component analysis (PCA) to compare the “fingerprint” of the air in Brescia with some source-related experimental and published data. This analysis showed that the PCDD/F fingerprints were more similar to steel plant emission data, while none of the PCB air patterns were comparable to emission profiles, indicating that different sources are responsible for the concentration of these two pollutants. The highest PCB concentrations detected in the areas closest to the chemical plant are indicative of its impact on the surrounding environment.  相似文献   
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