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81.
The disruption of endocrine systems due to environmental contaminants potentially impacts on the developmental, behavioural, regulatory and reproductive systems of animals. A major source of exposure of animals (terrestrial and aquatic) to endocrine-disrupting compounds is through contact with contaminated surface waters contaminated with sewage effluent and/or stormwater discharge. We studied the response to endocrine-disrupting compounds of Gambusia holbrooki mosquito fish resident of wetlands that were used for the storage of either treated sewage effluent or stormwater runoff. We found that fish from wetlands that received polluted waters directly from the source (treated sewage effluent or stormwater runoff) demonstrated a morphological response consistent with endocrine disruption. In contrast, fish in the second in the series of wetlands that housed treated sewage effluent did not show evidence of such response. However, those from the second in the series of stormwater receiving wetlands did display a morphological response, although it could be considered milder than was observed in fish from the first in this effluent stream. Fish were also smaller in the wetland that received sewage effluent directly from the sewage treatment plant than elsewhere. Although the differences were not statistically significant, the average size of fish in the first in the series of stormwater wetlands were also small and second only to those in the first sewage effluent wetland.  相似文献   
82.
A purebred female Beagle dog that had received 2,000 R of protracted wholebody gamma-irradiation from 60Co when 14 months old had hematologic changes consistent with a myeloproliferative disorder 3 years after the termination of radiation exposure. Peripheral blood and bone marrow findings during the 7-month period before death showed progressive anemia with increased numbers of platelets; immature granulocytes, monocytes and promonocytes. A period of partial remission occurred during which time the peripheral blood was aleukemic, although there was marked thrombocytosis and abnormal erythropoiesis which was evidenced by bizarre circulating nucleated red cells, anisocytosis, poikilocytosis and Howell-Jolly bodies. The dog had a terminal crisis with marked leukocytosis, most cells in the peripheral blood being bizarre monocytes and promonocytes. Tissues obtained at necropsy showed diffuse as well as focal infiltration of the spleen, liver, lymph nodes, heart, kidney and gastrointestinal wall with immature neoplastic cells resembling monocytes and monocytic precursors. The monocytic differentiation of the invasive cell population was confirmed by morphological, cytochemical, histological, ultrastructural and in vitro cell culture studies.  相似文献   
83.
The discovery of abundant autotrophic macrophytes living below 200 meters indicates their importance to primary productivity, food webs, sedimentary processes, and as reef builders in clear oceanic waters. Estimates concerning minimum light levels for macroalgal photosynthesis and macrophytic contributions to the biology and geology of tropical insular and continental borderlands must now be revised.  相似文献   
84.
The Sardinian mountain newt Euproctus platycephalus, endemic to the island of Sardinia, (Italy), is considered a rare and threatened species and is classed as critically endangered by IUCN. It inhabits streams, small lakes and pools on the main mountain systems of the island. Threats from climatic and anthropogenic factors have raised concerns for the long-term survival of newt populations on the island. MtDNA sequencing was used to investigate the genetic population structure and phylogeography of this endemic species. Patterns of genetic variation were assessed by sequencing the complete Dloop region and part of the 12SrRNA, from 74 individuals representing four different populations. Analyses of molecular variance suggest that populations are significantly differentiated, and the distribution of haplotypes across the island shows strong geographical structuring. However, phylogenetic analyses also suggest that the Sardinian population consists of two distinct mtDNA groups, which may reflect ancient isolation and expansion events. Population structure, evolutionary history of the species and implications for the conservation of newt populations are discussed.  相似文献   
85.
86.
A retrospective cohort study was conducted to determine the risk of bovine tuberculosis (TB) among animals sold out from herds that were free to trade animals during the year 2005 according to their bovine TB testing history during the year 2005. The present study sample comprised of 338,960 animals, of which 124,360 animals were sold out from herds that were restricted from trading at some stage during 2005 (bovine TB 'exposed') and 214,600 animals that were sold from herds which did not have their trading status withdrawn in 2005 (bovine TB 'non-exposed'). The overall risk of a diagnosis of bovine TB during the two-year period after the animals were sold out was 0.69 per cent. The odds of bovine TB were 1.91 higher for animals sold out from bovine TB 'exposed' herds compared with animals sold out from bovine TB 'non-exposed' herds (OR 95 per cent CI: 1.76 to 2.07, P<0.0001). Ten per cent of animals identified during field surveillance with bovine TB did so less than two months after being sold out in 2005, and similarly, 10 per cent of the animals classified as bovine TB positive by finding a bovine TB lesion at slaughter did so within 25 days (or less) of being sold out in 2005.  相似文献   
87.
The effects of feed removal for 6, 8, or 10 h during the day from 8 to 28 days of age followed by ad libitum feeding to market age on the growth performance of two strains of broiler chickens, Ross 308 and Hubbard, were studied over 7 weeks. Ross 308 was superior to Hubbard in weight gain and final body weight but consumed more feed and deposited more abdominal fat. Overall, daily feed removal reduced feed intake and improved feed efficiency in all feed-restricted birds, and the longer the period of feed removal the better the efficiency of utilization, but it had no significant effect on weight gain and market weight. It is suggested that for broiler production in the tropics, Ross 308 could be used on a 10-h daily feed removal program from 8 to 28 days of age.  相似文献   
88.
OBJECTIVE: To report on the variety and total number of food items recorded by a true longitudinal group of urban black South African children (n = 143) from the Birth-to-Twenty Study at five interceptions at the ages of 5 (1995), 7 (1997), 9 (1999), 10 (2000) and 13 (2003) years, respectively. METHODS: Dietary intake was assessed using a semi-quantitative food-frequency questionnaire. Frequencies were calculated per week, for each interception and for all five interceptions combined, using SAS. RESULTS: Five hundred and forty-six different individual food items were recorded 23 480 times for all five interceptions combined. The highest of 124 items was recorded in 1999 contributing 23% of the 546 items recorded. Each of the top 10 items (rice, stiff maize-meal porridge, chicken, sugar, sweets, tea, eggs, full-cream milk, carbonated beverages and oil) contributed between 2.5% and 3% and these items were recorded almost 600 times or more for all interceptions combined (n = 23 840). Rice and stiff maize-meal porridge were the top items recorded 684 and 676 times, both contributing 2.87% and 2.84%, respectively. The variety of food items and the ratio of the food groups to the total number of foods recorded in the present study were not significantly different but the denominators decreased over the five interceptions. CONCLUSION: The variety of food items recorded did not vary between 1995 and 2003 - the fact that new items were not added to the questionnaire as the children grew older could have contributed to this phenomenon. However, there was a difference in the ranking of these items that may suggest a change in eating patterns.  相似文献   
89.
Genetic diversity between three farmed and four wild populations of Atlantic salmon from Ireland and Norway were analysed using 15 microsatellite markers. High levels of polymorphism were observed over all populations with the average number of alleles and average heterozygosity at 17.8 and 0.70, respectively. Farmed salmon showed less genetic variability than wild salmon in terms of allelic diversity but not necessarily in terms of overall heterozygosity. Between farmed populations significant differences were observed in expected heterozygosity suggesting that more intensive breeding practices may have resulted in a further erosion of genetic variability. Phylogenetic analysis using either populations or individuals as nodes show a clustering of populations into two groups, farmed and wild. This suggests that founder effects and subsequent selection have had more effect on the genetic differentiation between these strains than geographical separation. This technology has great potential for use in aquaculture situation where levels of genetic variation could be monitored and inbreeding controlled in a commercial breeding progra.  相似文献   
90.
The calcium carbonate in freshwater clam shells is simlilar in purity to that designated reagent grade. A simple reprecipitation of the shell extract results in a product having less Sr and Mg than reagent grade CaCO(3). Clams are harvested commercially, and discarded shells are a high-quality raw material for the production of CaCO(3).  相似文献   
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