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911.
912.
Management activities such as law enforcement and community outreach are thought to affect conservation outcomes in protected areas, but their importance relative to intrinsic environmental characteristics of the parks and extrinsic human pressures surrounding the parks have not been explored. Furthermore, it is not clear which is more related to conservation outcomes—the management itself or local people's perceptions of the management. We measured objective (reports by park staff) and subjective (reports by local people) levels of community outreach and law enforcement based on responses to 374 questionnaires. We estimated mammal abundance and diversity of 6 protected areas based on data from 115 camera traps in Xishuangbanna, southwest China, a biodiversity hotspot with high hunting and land-conversion pressures. We then examined correlations among them and found that local people's perception of law enforcement was positively related to the local abundance of 2 large, hunted species, wild boar (Sus scrofa) (β = 15.22) and muntjac (Muntiacus vaginalis) (β = 14.82), but not related to the abundance of smaller mammals or to objective levels of enforcement. The subjective frequency of outreach by park staff to local communities (β = 3.42) and park size (β = 3.28) were significantly and positively related to mammal species richness, whereas elevation, human population density, and subjective frequency of law enforcement were not. We could not conclude that community outreach and law enforcement were directly causing increased mammal abundance and diversity. Nevertheless, the patterns we detected are some of the first empirical evidence consistent with the idea that biodiversity in protected areas may be more positively and strongly related to local perceptions of the intensity of park management than to either intrinsic (e.g., elevation, park size) or extrinsic (e.g., human population density) environmental factors.  相似文献   
913.
孕激素是广泛使用的高生物活性药物,其残留广泛存在于水环境中,对水生生物造成潜在威胁。本论文研究孕激素左炔诺孕酮(LNG)长期暴露对雄性斑马鱼的生殖毒性。将斑马鱼胚胎暴露于环境相关浓度的LNG(10, 33, 100 ng·L~(-1))至性成熟(受精后142 d),得到100%的雄性斑马鱼。将得到的雄鱼与未暴露的雌鱼配对,结果发现100 ng·L~(-1) LNG处理组雄鱼使得未暴露雌鱼产卵的数量较对照组雄鱼使得未暴露雌鱼产卵的数量显著减少。33和100 ng·L~(-1)处理组雄鱼与未暴露雌鱼配对所得子代在受精后7 d内的存活率较对照组雄鱼与未暴露雌鱼配对所得子代的存活率显著降低。33 ng·L~(-1) LNG显著升高总活力、活跃精子活力、平均路径速度、直线运动速度、曲线运动速度等精子活力参数,但其他浓度的LNG并不影响精子的活力。LNG在33和100 ng·L~(-1)的浓度下显著降低雄鱼血浆中11-酮基睾酮(11-KT)的含量,且在3个浓度下均显著降低雄鱼血浆中雌二醇(E2)的含量,但对睾酮(T)无明显影响。此外,LNG暴露可干扰雄鱼大脑和精巢中孕激素受体(npr, mprα, mprβ)、雌激素受体(erα, erβ)以及雄激素受体(ar)的转录,可能通过这些受体途径参与生殖调控。研究结果表明环境相关浓度的左炔诺孕酮长期暴露可导致雄性斑马鱼的生殖内分泌干扰效应,并提示:仅雄鱼单独受孕激素暴露影响,也可能对鱼类种群的生殖产生深远影响。  相似文献   
914.
聚磷生物膜的快速启动及微生物特性研究   总被引:2,自引:0,他引:2  
章豪  高碧霄  潘杨  冯鑫 《环境科学学报》2019,39(10):3317-3324
在同步去除并富集磷的基础上,探究采用前期不排泥、后期排泥的挂膜方式对聚磷生物膜反应器的运行效能、微生物特征及群落结构的影响.结果表明,经过驯化运行,聚磷生物膜的蓄磷能力明显提升.在挂膜阶段,生物膜厚度及EPS含量出现一定程度的增长;PN/PS上升至3.12,PN/PS比值增加有利于微生物粘附在填料上.在好氧出水达标的情况下,富集液中磷酸盐浓度提升至89.5 mg·L~(-1),达到了鸟粪石回收标准.高通量测序结果表明,经过富集培养,微生物群落多样性呈下降趋势,群落组成变化明显.优势菌门为变形菌门(Proteobacteria),其丰度从33.6%增长至75.3%;反应器中的聚磷菌属丰度明显增加,从11.8%上升至23.2%,红环菌属(Rhodocyclaceae)、UKL 13-1为反应器中的优势聚磷菌.  相似文献   
915.
This paper discusses the scientific background and content of the ecological assessment of cities, and takes Boda, a new town in Xinjiang province, China, as a case study.  相似文献   
916.
A deterministic linear programming model which optimizes the abatement of each SO2 emission source, is extended into a CCP form by introducing equations of probabilistic constrained through the incorporation of uncertainty in the source-receptor-specific transfer coefficients. Based on the calculation of SO2 and sulfate average residence time for Liuzhou City, a sulfur deposition model has been developed and the distribution of transfer coefficients have been found to be approximately log-normal. Sulfur removal minimization of the model shows that the abatement of emission sources in the city is more effective, while control cost optimization provides the lowest cost programmes for source abatement at each allowable deposition limit under varied environmental risk levels. Finally a practicable programme is recommended.  相似文献   
917.
在Pt/Al_2O_3催化剂上用外循环无梯度反应器研究了异丁醇完全氧化动力学,异丁醇完全氧化动力学方程用异丁醇及氧吸附,CO_2吸附阻碍的L-H模型描述,用正交设计法求出动力学方程中的参数,用脉冲法测定了异丁醇、氧及CO_2的吸附热。  相似文献   
918.
Abstract

The Models-3 Community Multiscale Air Quality (CMAQ) Modeling System and the Particulate Matter Comprehensive Air Quality Model with extensions (PMCAMx) were applied to simulate the period June 29–July 10, 1999, of the Southern Oxidants Study episode with two nested horizontal grid sizes: a coarse resolution of 32 km and a fine resolution of 8 km. The predicted spatial variations of ozone (O3), particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5), and particulate matter with an aerodynamic diameter less than or equal to 10 μm (PM10) by both models are similar in rural areas but differ from one another significantly over some urban/suburban areas in the eastern and southern United States, where PMCAMx tends to predict higher values of O3 and PM than CMAQ. Both models tend to predict O3 values that are higher than those observed. For observed O3 values above 60 ppb, O3 performance meets the U.S. Environmental Protection Agency's criteria for CMAQ with both grids and for PMCAMx with the fine grid only. It becomes unsatisfactory for PMCAMx and marginally satisfactory for CMAQ for observed O3 values above 40 ppb.

Both models predict similar amounts of sulfate (SO4 2?) and organic matter, and both predict SO4 2? to be the largest contributor to PM2.5. PMCAMx generally predicts higher amounts of ammonium (NH4 +), nitrate (NO3 ?), and black carbon (BC) than does CMAQ. PM performance for CMAQ is generally consistent with that of other PM models, whereas PMCAMx predicts higher concentrations of NO3 ?,NH4 +, and BC than observed, which degrades its performance. For PM10 and PM2.5 predictions over the southeastern U.S. domain, the ranges of mean normalized gross errors (MNGEs) and mean normalized bias are 37–43% and –33–4% for CMAQ and 50–59% and 7–30% for PMCAMx. Both models predict the largest MNGEs for NO3 ? (98–104% for CMAQ, 138–338% for PMCAMx). The inaccurate NO3 ? predictions by both models may be caused by the inaccuracies in the ammonia emission inventory and the uncertainties in the gas/particle partitioning under some conditions. In addition to these uncertainties, the significant PM overpredictions by PMCAMx may be attributed to the lack of wet removal for PM and a likely underprediction in the vertical mixing during the daytime.  相似文献   
919.
A heterologous indirect enzyme-linked immunosorbent assay (ELISA) was developed, which was based on monoclonal antibody (Mab) to determine parathion residue in agricultural and environmental samples. Eight Mabs were produced by introducing the heterologous indirect ELISA into the screening procedure. It was shown that these Mabs had more broad-reactivity with twenty competitors than that of 5H7 (Mab produced by homologous screening). So it became much easier using these new Mabs to develop heterologous immunoassays. In addition, all the developed heterologous ELISAs could be used to determine parathion residue in semiquantitative or quantitative level, and their detection limitation (LOD) was around 2 ng/mL. Compared with the previous heterologous ELISA (hapten 11/5H7) with IC50 of 13.3 ng/mL, a better heterologous ELISA (hapten 11/1E1) was obtained with IC50 of 3.8 ng/mL, which improved the sensitivity 3.5 times. Finally, the latter was applied to parathion residue determination in spiked agricultural and environmental samples without extraction or cleanup. The average recoveries of parathion added to water, soil, cucumber, Chinese cabbage and carrot were between 80.4 % and 111.8 %. The LOD for water and soil samples was 5 ng/mL, and the LOD for cucumber, rice and corn samples was 10 ng/mL.  相似文献   
920.
As important members of the zooplankton community and sources of food for fish, rotifers are used extensively in ecotoxicological research to assess the health of the environment and safety of compounds. However, most rotifer toxicity tests are only conducted using rotifer neonates derived from unexposed mothers, thus ignoring the potential transfer of contaminants from mother to offspring. To understand better the mother to offspring exposure, a multigenerational study was conducted using three successive generations (F0, F1 and F2) of the common freshwater rotifer Brachionus calyciflorus to investigate the toxic effects of the widely used organophosphate pesticide, dimethoate (O, O-dimethyl S-methylcarbamoylmethyl phosphorodithioate). When the F0 generation was exposed to five pesticide concentrations, the population growth rate (r) displayed symptoms of hormesis, characterized by the conversion of low-concentration stimulation to high-concentration inhibition. Despite this observation, the exposure to any given concentration of dimethoate reduced the population growth rates of the F1 and F2 generation rotifers. Significant differences existed between the F0, F1 and F2 rotifers for the population growth rate under dimethoate stress: F2 individuals were more sensitive than F1, whereas the F1 individuals were more sensitive than F0. The results indicated that the parental exposure to a given toxic stress could result in increased sensitivity and decreased fitness in the offspring. This study illustrates the utility of multigenerational toxicity tests, which may better reflect and more accurately predict the effects of long-term pesticide exposure to aquatic organisms at the population level.  相似文献   
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