Attribution of human infections with Shiga toxin‐producing Escherichia coli (STEC) to livestock sources and identification of source‐specific risk factors,The Netherlands (2010–2014)

Shiga toxin‐producing Escherichia coli (STEC) is a zoonotic pathogen of public health concern whose sources and transmission routes are difficult to trace. Using a combined source attribution and case–control analysis, we determined the relative contributions of four putative livestock sources (cattle, small ruminants, pigs, poultry) to human STEC infections and their associated dietary, animal contact, temporal and socio‐econo‐demographic risk factors in the Netherlands in 2010/2011–2014. Dutch source data were supplemented with those from other European countries with similar STEC epidemiology. Human STEC infections were attributed to sources using both the modified Dutch model (mDM) and the modified Hald model (mHM) supplied with the same O‐serotyping data. Cattle accounted for 48.6% (mDM) and 53.1% (mHM) of the 1,183 human cases attributed, followed by small ruminants (mDM: 23.5%; mHM: 25.4%), pigs (mDM: 12.5%; mHM: 5.7%) and poultry (mDM: 2.7%; mHM: 3.1%), whereas the sources of the remaining 12.8% of cases could not be attributed. Of the top five O‐serotypes infecting humans, O157, O26, O91 and O103 were mainly attributed to cattle (61%–75%) and O146 to small ruminants (71%–77%). Significant risk factors for human STEC infection as a whole were the consumption of beef, raw/undercooked meat or cured meat/cold cuts. For cattle‐attributed STEC infections, specific risk factors were consuming raw meat spreads and beef. Consuming raw/undercooked or minced meat were risk factors for STEC infections attributed to small ruminants. For STEC infections attributed to pigs, only consuming raw/undercooked meat was significant. Consuming minced meat, raw/undercooked meat or cured meat/cold cuts were associated with poultry‐attributed STEC infections. Consuming raw vegetables was protective for all STEC infections. We concluded that domestic ruminants account for approximately three‐quarters of reported human STEC infections, whereas pigs and poultry play a minor role and that risk factors for human STEC infection vary according to the attributed source.     

Fishing efficiency of competitive largemouth bass tournament anglers has increased since early 21st century

Tournament fishing has risen in popularity over the last half a century. As such, social and financial incentives combined with technological advancements are expected to drive changes in angler's capacity to exploit tournament‐eligible fish stocks, as has been observed in commercial fisheries. The aim of this study was to quantify temporal trends in angler efficiency and their ability to exploit a given fish stock relative to effort in largemouth bass fishing tournaments. A collective analysis across seven Illinois reservoirs comparing change through time in angler catch rates and relative population abundances indicated that angler efficiency has generally improved through time. For the decade from 2005 to 2015, a greater than threefold increase in the efficiency of anglers to exploit a static population of largemouth bass was estimated. Anglers have become more efficient at exploiting populations, which is likely to influence management decisions in the future, particularly in harvest‐orientated fisheries and those reliant upon fishery‐dependent surveys.     

湖北省小型水库设计洪水与防洪复核方法探讨

设计洪水和防洪复核成果是水库除险加固与设计的基本依据,对水库除险加固与设计有着重要影响。针对湖北省小型水库设计洪水与防洪复核的方法,从水库基本资料复核、防洪标准确定、设计洪水推求、设计暴雨推求、设计净雨过程推求、设计洪水推求、水库防洪能力复核、需要注意的几个关键问题等方面进行了探讨,为水库除险加固与设计等类似的工程提供了参考。     

如何在湖泊水库中进行不投饵网箱养殖鲢鳙鱼

从不投饵网箱养殖鲢鳙鱼的优点以及相关的技术2个方面,论述在湖泊水库中进行不投饵鲢鳙鱼的网箱养殖技术方法。     

北美典型储气库的技术发展现状与启示

地下储气库是天然气市场的重要组成部分,在调峰和保障供气安全上具有不可替代的作用.我国储气库的建设近年来发展较快,但与北美地区相比,仍处于起步阶段.通过对北美地区储气库现状、运营管理、技术特点等进行调研,总结了国外储气库在设计、建设和经营管理等方面的经验.对我国储气库的发展提出建议:借鉴北美储气库在日常运营管理方面的模式;强化钻井技术方面的研究力度,通过采用大孔径水平井,提高单井注采能力;加强材料的创新性研究.     

基于协同差分演化算法的梯级水库短期发电优化调度研究

随着我国水电事业不断发展,流域梯级水库群联合调度的新格局已逐渐形成.针对梯级水库发电优化调度问题,在差分演化算法中适应度的进化模式中计及进化成分与外部环境之间的内在联系,借鉴生态学对个体生存环境与种群竞争的关系,提出了协同差分演化算法,并将其引入梯级水库短期发电优化调度中.实例仿真计算结果表明,该算法具有可靠性与合理性,计算速度显著提升,为解决高维复杂、多约束、非线性的梯级水库优化调度问题提供了一条新路径.     

辽宁5座水源地水库底栖动物群落结构特征比较

为探究辽宁省5座水源地水库—观音阁、白石、柴河、清河和汤河水库底栖动物的群落结构特征,并根据底栖动物的现存量估算鱼产潜力,为这5座水库保水渔业的放养捕捞提供科学依据,于2019-2020年开展季节性调查,共检出底栖动物67种,其中,节肢动物52种,以摇蚊幼虫为主,有39种;寡毛类12种,主要为颤蚓和仙女虫;软体动物3种,分别为观音阁和汤河水库检出的椭圆萝卜螺,以及观音阁和白石水库的梨形环棱螺和褶纹冠蚌。检出种类以汤河水库最多,39种,其次为观音阁水库34种,白石水库最少,仅23种。密度以白石水库最高,1 546.89 ind/m²,其次为观音阁水库658.33 ind/m²,汤河水库最低,481.92 ind/m²。生物量以白石水库最高,7.76 g/m²,其次为汤河水库5.68 g/m²,清河水库最低,2.49 g/m²。5座水库密度在春、夏、秋季均可出现峰值,但最低值皆出现在夏季;生物量则以春、冬季较高,夏、秋季较低。各库密度和生物量总体表现为静水区最高,仅观音阁水库密度和生物量、白石水库生物量峰值出现在过渡区。观音阁和柴河水库河流区至坝前密度和生物量总体以寡毛类为主,而入水口以摇蚊幼虫占比最高;清河水库和汤河水库入水口至静水区密度和生物量总体以摇蚊幼虫为主,而坝前均以寡毛类占比最高;白石水库入水口至过渡区主要为摇蚊幼虫,坝前静水区以寡毛类为主。群落聚类与MDS排序结果显示,观音阁、柴河和清河水库群落较为相似,而白石水库和汤河水库群落相似性较低,且与观音阁、柴河和清河水库差异明显。CCA结果显示,水深、总氮、氨氮、DOC、叶绿素a含量是5座水库影响底栖动物密度的关键因子。底栖动物种类组成受总氮、氨氮影响明显,汤河水库总氮、氨氮含量最低,表现为种类最多,摇蚊幼虫优势地位高;白石水库中总氮、氨氮含量最高,表现为种类最少,水丝蚓优势地位高。基于底栖动物估算的鱼产潜力白石水库最高,汤河水库次之,清河水库最低。与以往调查数据相比,5座水库种类数均增加,主要是检测出的摇蚊幼虫种类增加;而密度和生物量表现有所不同,观音阁水库密度和生物量均降低,而清河和汤河水库均增加,白石水库则密度增加而生物量降低,柴河水库则密度降低而生物量增加。以上结果表明,应根据这5座水源地水库底栖动物群落结构特征,针对性地管理底栖动物食性鱼类的放养和捕捞。     

City sanitation and socioeconomics predict rat zoonotic infection across diverse neighbourhoods

Rat‐associated zoonoses transmitted through faeces or urine are of particular concern for public health because environmental exposure in homes and businesses may be frequent and undetected. To identify times and locations with greater public health risks from rats, we investigated whether rat characteristics, environmental features, socioeconomic factors, or season could predict rat infection risk across diverse urban neighbourhoods. In partnership with a pest management company, we sampled rats in 13 community areas along an income gradient in Chicago, a large city where concern about rats has increased in recent years. We collected kidneys for Leptospira spp. testing and colon contents for aerobic bacteria such as Salmonella spp. and Escherichia coli. Of 202 sampled rats, 5% carried Leptospira spp. and 22% carried E. coli. Rats were significantly more likely to carry Leptospira spp. on blocks with more standing water complaints in higher‐income neighbourhoods (OR = 6.74, 95% CI: 1.54–29.39). Rats were significantly more likely to carry E. coli on blocks with more food vendors (OR = 9.94, 2.27–43.50) particularly in low‐income neighbourhoods (OR = 0.26, 0.09–0.82) and in the spring (OR = 15.96, 2.90–88.62). We detected a high diversity of E. coli serovars but none contained major virulence factors. These associations between environmental features related to sanitation and infection risk in rats support transmission through water for Leptospira spp. and faecal–oral transmission for E. coli. We also found opposing relationships between zoonotic infection risk and income for these two pathogens. Thus, our results highlight the importance of sanitation for predicting zoonotic disease risks and including diverse urban areas in pathogen surveillance to mitigate public health risks from rats.     

干旱区平原水库防蒸发节水试验初探

针对干旱区平原水库面积大、水深浅,无效蒸发损失严重这一特点,提出用聚苯乙烯泡沫塑料板覆盖部分库区水面以减少无效蒸发损失量,从而提高水库的有效利用率.以尉犁县塔里木二库为试验对象现场试验,初步探讨干旱区平原水库防蒸发节水的工程措施.     

汕头市中小水库库区水源林调查研究初报

以汕头市的中小水库库区水源涵养林林分为研究对象 ,通过调查几个比较有代表性的水库库区的植物情况、土壤主要理化状况 ,从而探讨不同森林群落植物多样性与涵养水源功能的关系 ,为进一步确定不同立地、不同类型林分的改造树种和造林模式提供科学依据