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51.
Efforts to exclude disease organisms from farms growing irrigated lettuce and leafy vegetables on California's central coast are conflicting with traditionally accepted strategies to protect surface water quality. To begin resolving this dilemma, over 100 officials, researchers, and industry representatives gathered in April 2007 to set research priorities that could lead to effective co-management of both food safety and water quality. Following the meeting, research priorities were refined and ordered by way of a Delphi process completed by 35 meeting participants. Although water quality and food safety experts conceptualized the issues differently, there were no deep disagreements with respect to research needs. Top priority was given to investigating the fate of pathogens potentially present on farms. Intermediate priorities included characterizing the influence of specific farm management practices on food safety and improving our understanding of vector processes. A scientific subdiscipline focusing on competing risks is needed to characterize and resolve conflicts between human and environmental health.  相似文献   
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Bacterial counts, carried out bi-mouthly over 2 years, at diverse localities on the Provence shores (France), revealed that the bottom-water microflora is not dependent on chemical and biological characteristics of the upper sediment layer. Freshwater inflow, polluted or non-polluted, and high concentrations of suspended particulate matter usually induce the highest bacterial counts. The concentration of microflora in marine muds and sands is connected with their organic content. There is no apparent correlation with water microflora concentration or macrobenthos density. The area of highest bacterial concentration is restricted to a narrow, thin belt of littoral sediment. Bacterial transformation is probably more important in the water mass as a whole than in marine deposits. The annual range of variations in microflora distribution is higher than the range which was encountered when testing the validity of the bacterial count method with the sampling technique employed. Certain bacterial concentrations, appearing simultaneously in different sediment layers and at different stations seem to be related to ecological factors. Such variations seem to realize a true annual cycle. The highest counts occur during the warm season, unlike the phytoplankter populations. Bacterial proliferation in water masses usually succeeds to phytoplankton blooms.  相似文献   
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Based on the concentration of Malathion used in the field, we evaluated the genotoxic potential of low concentrations of this insecticide on meristematic and F1 cells of Allium cepa and on rat hepatoma tissue culture (HTC cells). In the A. cepa, chromosomal aberrations (CAs), micronuclei (MN), and mitotic index (MI) were evaluated by exposing the cells at 1.5, 0.75, 0.37, and 0.18 mg/mL of Malathion for 24 and 48 hr of exposure and 48 hr of recovery time. The results showed that all concentrations were genotoxic to A. cepa cells. However, the analysis of the MI has showed non-relevant effects. Chromosomal bridges were the CA more frequently induced, indicating the clastogenic action of Malathion. After the recovery period, the higher concentrations continued to induce genotoxic effects, unlike the observed for the lowest concentrations tested. In HTC cells, the genotoxicity of Malathion was evaluated by the MN test and the comet assay by exposing the cells at 0.09, 0.009, and 0.0009 mg/5 mL culture medium, for 24 hr of exposure. In the comet assay, all the concentrations induced genotoxicity in the HTC cells. In the MN test, no significant induction of MN was observed. The genotoxicity induced by the low concentrations of Malathion presented in this work highlights the importance of studying the effects of low concentrations of this pesticide and demonstrates the efficiency of these two test systems for the detection of genetic damage promoted by Malathion.  相似文献   
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Ninety five sediment samples were extracted from 16 cores collected at depths from 283 to 4,350 m in the Eastern Mediterranean Sea. Generally, the microbial population of superficial layers is lower than 105 bacteria/g sediment. At depths below 1,000 m this population is lower than 104. Bacterial counts at different levels of the sediment show that the microbial population is only important in the superficial layer. Below the surface, bacterial counts are generally between 102 to 103 cells/ml. Some levels appear to be sterile; none of the 12 culture media gave rise to development with the sediment samples. Studies of some physiological groups of bacteria show scarcity of chitinoclastic and agarolytic bacteria and absence of cellulolytic and sulphate reducers. On the other hand, amylolytic, gelatinolytic, lypolytic and nitrate-reducing bacteria are widely distributed among the microbial population of marine sediments. This population of deep sediments includes a few auxotrophic bacteria.  相似文献   
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Environmental Science and Pollution Research - Due to its peculiarity to accumulate environmental contaminants, the osprey Pandion haliaetus is a sentinel species for the biomonitoring of...  相似文献   
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In its successful annual cycle of controversies and debates, the International Society of Prenatal Diagnosis and Therapy once again addressed non-invasive prenatal testing (NIPT) by following up on the 2013 controversy, ‘Should non-invasive DNA testing be the standard screening test for Down syndrome in all pregnant women’? with the proposition, ‘NIPT for chromosomel abnormalities should be offered to women with low a priori risk’. © 2014 John Wiley & Sons, Ltd.  相似文献   
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