Geographical Environment for the Safe Production of Food

Food is essential for human survival, but harmful, toxic substances in food damage and threaten human health. Food production is inseparable from the place where the food is produced; that is, from the geographical environment that consists of natural and human environments, two parts of a unified whole. China’s territory is vast and its geographical environment is complex and diverse. Food production patterns in different parts of the country vary significantly, as do local socio-economic and cultural conditions. Such differences have an enormous impact on food safety. Based on the geographical area where food is produced in China, this paper reveals the main environmental problems arising from industrial and agricultural production activities, and related risks for food safety and health. In concluding, we make some recommendations for countermeasures. The main food safety related environmental problems include the excessive application of chemical fertilizers and pesticides; high background levels of heavy metals; discharge of wastewater and heavy metals; and excessive use of additives and antibiotics in livestock and poultry breeding and aquatic products. All these issues can lead to huge risks for food safety and thus health. These are not simply scientific issues, but also political, economic and legal issues, as well as social problems that differ from region to region. Therefore, comprehensive studies are needed to identify risks to food safety and health hazards in different areas. Systematic and comprehensive risk assessments of health problems caused by changing ecosystems, environmental pollution, nutrition problems and lifestyle, and especially comprehensive risk assessments of regional environmental changes and health risks are needed. Measures based on an understanding of local conditions must be put forward to protect food safety and health, to strengthen multi-sectoral management, and to improve environmental quality     

Modeling the Warming Impact of Urban Land Expansion on Hot Weather Using the Weather Research and Forecasting Model: A Case Study of Beijing,China

The impacts of three periods of urban land expansion during 1990–2010 on near-surface air temperature in summer in Beijing were simulated in this study, and then the interrelation between heat waves and urban warming was assessed. We ran the sensitivity tests using the mesoscale Weather Research and Forecasting model coupled with a single urban canopy model,as well as high-resolution land cover data. The warming area expanded approximately at the same scale as the urban land expansion. The average regional warming induced by urban expansion increased but the warming speed declined slightly during 2000–2010. The smallest warming occurred at noon and then increased gradually in the afternoon before peaking at around 2000 LST—the time of sunset. In the daytime, urban warming was primarily caused by the decrease in latent heat flux at the urban surface. Urbanization led to more ground heat flux during the day and then more release at night, which resulted in nocturnal warming. Urban warming at night was higher than that in the day, although the nighttime increment in sensible heat flux was smaller. This was because the shallower planetary boundary layer at night reduced the release efficiency of near-surface heat. The simulated results also suggested that heat waves or high temperature weather enhanced urban warming intensity at night. Heat waves caused more heat to be stored in the surface during the day, greater heat released at night, and thus higher nighttime warming. Our results demonstrate a positive feedback effect between urban warming and heat waves in urban areas.     

ENSO与西北太平洋强TC相关关系年代际变化研究

利用美国联合台风警报中心(Joint Typhoon Warning Center,JTWC),中国气象局(China Meteorological Administration,CMA)上海台风所,日本气象厅(Japan Meteorological Agency,JMA)的台风最佳路径资料以及美国NCAR/NCEP再分析资料等,深入研究厄尔尼诺—南方涛动(El Ni1o-Southern Oscillation,ENSO)与西北太平洋强热带气旋(Tropical Cyclone,TC),即1 min最大风速大于等于114 kn相关关系的变化。结果表明,ENSO与热带西北太平洋(Western North Pacific,WNP)强TC频数之间的相关关系存在明显年代际变化。在1960—1971年期间(前一阶段),强TC年频数与Ni1o3. 4(11月—次年1月平均)相关性较弱;而在1983—2014年期间(后一阶段)两者的相关性则为强的正相关。并且强TC的年频数、生命史以及生成位置在后一阶段El Ni1o和La Ni1a年之间的差异相比前一阶段都有明显的增大。进一步分析发现:热带太平洋海温异常(Sea Surface Temperature Anomaly,SSTA)的西移是造成后一阶段Ni1o3. 4指数与强TC年频数相关性提高的关键因素。在后一阶段的El Ni1o(La Ni1a)年,SSTA的西移使得WNP东南象限的相对湿度明显增加(减少),从而有利于(不利于) TC在此象限生成。又因为位于东南象限的TC比较容易发展成强TC,因此导致后一阶段的El Ni1o(La Ni1a)年有更多(更少)的强TC在西北太平洋的东南象限生成。     

甲壳动物中的酚氧化酶原激活系统研究评价

依据８０－９０年代国际关于甲壳动物免疫机制的资料,对甲壳动物中的酚氧化酶原激活系统的研究进展予以综合评价,目的在于为中国科技工作者防治虾蟹类疾病提供参考。现有的研究表明,甲壳动物中的酚氧化酶原激活系统可被微生物多糖激尖,在激活过程中产生一系列活性物质,通过多种形式参与宿主防御反应。在甲壳动物中,与ｐｒｏＰＯ系统有关的因子正在被逐步纯化出来;ｐｒｏＰＯ可由内源蛋白酶转化成活性形式,存在调节因子调节ｐ     

pH胁迫对菲律宾蛤仔(Ruditapes philippinarum)耗氧率、排氨率、免疫和抗氧化酶活性以及组织形态的影响

随着人类工业迅速发展, CO2大量排放,引起了海洋的酸化效应,不仅导致了全球气候变暖,也严重危害了海洋生物的生态健康。以菲律宾蛤仔(Ruditapes philippinarum)为研究对象,研究pH变化对菲律宾蛤仔耗氧率、排氨率、鳃组织结构以及鳃和内脏团的免疫、抗氧化酶活性的影响。将菲律宾蛤仔置于酸化海水(pH 6.4、7.1和7.7)中,以自然海水(pH 8.1)为对照。结果表明:耗氧率和排氨率随着pH的升高或降低而降低,在pH=8时达到最大值; 6.4酸化组蛤仔鳃组织结构损伤严重,鳃丝间距扩大,纤毛黏合;鳃组织碱性磷酸酶(AKP)第42天所有酸化组活性显著高于对照组(P<0.05),所有酸化组溶菌酶(LZM)和酸性磷酸酶(ACP)活性显著低于对照组(P<0.05), 7.7酸化组超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活性和总抗氧化能力(T-AOC)显著高于对照组(P<0.05),所有酸化组丙二醛(MDA)含量显著低于对照组(P<0.05);内脏团7.1和7.7酸化组LZM活性显著高于对照组(P<0.05),...     

巢湖四条入湖河流硝态氮污染来源的氮稳定同位素解析

采用氮稳定同位素技术对巢湖四条主要污染输入河流(南淝河、十五里河、派河和双桥河)的氮污染状况和硝态氮来源进行研究.结果表明,巢湖四条入湖河流氮污染最严重的是十五里河,其次是南淝河和派河,双桥河的污染相对较轻.硝态氮的稳定同位素分析结果表明,巢湖四条入湖河流的硝态氮污染物在季节上受到不同因子的影响.十五里河和南淝河的硝态氮污染主要来源于城市生活污水和工业废水;派河的硝态氮污染在冬季主要来源于工业废水,春季来源于农业面源,而在夏季主要受到雨水的影响;双桥河的硝态氮污染冬、春季主要来源于农业面源,夏季主要受雨水的影响.此外本研究结果还表明巢湖四条主要入湖河流的氮污染源主要为铵态氮,因此今后要对铵态氮的来源进行同位素示踪.     

海面水包油乳化液溢油量等效估算方法研究

激光诱导荧光(LIF)是一种主动光学探测技术,该技术已在海面未乳化溢油油种鉴别及油膜厚度评估方面取得了一定的研究成果,但乳化溢油的监测理论基础和探测方法尚未成熟。溢油乳化物的量化会直接影响溢油污染的应急处理和灾害评估,但目前对溢油乳化液溢油量的计算尚未有研究报道。本文以水包油乳化液为研究对象,基于等效思想,根据油量相等建立了水包油乳化液与油膜的荧光检测等效模型,并依据光的辐射传输机理推导出等效油膜厚度的估算公式,最后采用仿真实例对估算方法的适用性和有效性进行了验证。实验结果表明,当水包油乳化液含油率小于12×10^-6,厚度小于5.98 cm时,利用所提出的等效方法能有效计算出水包油实际溢油厚度。该方法可为海面乳化溢油量的估算提供一种创新性的方法,具有良好的借鉴意义和实际应用价值。     

湖北长湖水生植物多样性及群落演替

在2011年的调查基础上,结合已有资料,研究长湖水生植物多样性、群落特征、水生植被分布现状及水生植物多样性的动态变化和群落演替规律,探讨驱动水生植物群落演替的主导因素.结果显示长湖现有水生植物95种,水生植物优势群落12个.与1985年相比,长湖水生植物无论是在优势种还是优势群落上均发生了巨大变化,从原来以沉水植物为主的优势群落逐步演替为以挺水植物+漂浮浮叶植物为优势的水生植物群落.同时水生植被分布面积急剧缩小,生物量显著下降,2011年全湖水生植被覆盖率仅为4.2%,单位面积平均生物量只有2001年的10%,全湖生物总量相比于2006年下降了88.5%.分析表明,大规模围网养殖等人为干扰活动及水体富营养化是致使长湖水生植物多样性显著下降和群落发生逆向演替的主要原因.     

利用重复地震研究盖州震群地区介质变化

盖州震群自2012年2月2日开始活动,截至2016年12月已活动了近5年的时间,其中持续活动的青石岭序列精定位后的空间展布在5km以内,深度也较为集中,可作为重复地震进行研究。通过计算盖州地区2012年2月—2016年12月M_L≥2.0重复地震序列经射线追踪法校正后的P波走时差,得到了盖州震群区域至岫岩台、辽阳台、高升台、瓦房店台四象限的介质变化情况,结果介质短期的变化受震群本身显著事件活动影响较为明显。中强地震前后周边地区介质变化显著。     

基于奇异谱分析的静态相对重力观测重力固体潮提取

针对相对重力测量数据中存在的重力固体潮信号,本文提出将奇异谱分析方法（Singular Spectrum Analysis,SSA）应用到相对重力测量数据处理中,在不需要测站坐标等先验信息的条件下从相对重力数据中提取重力固体潮,提供了一种获取重力固体潮的新思路.采用模拟的相对重力数据进行实验,利用SSA方法和小波变换方法分别从模拟信号中提取重力固体潮并进行结果对比,SSA获取的重力固体潮与理论值残差RMS为0.3 μGal,小波方法获取的残差RMS为1.6 μGal.利用CG-5相对重力仪实测数据进行实验,提出一种利用SSA外推时间序列来削弱边界效应的新思路,实验结果显示采用这种方法后重力固体潮值与理论值残差序列的RMS和STD均有所减小.通过实验发现削弱边界效应后SSA提取的重力固体潮与采用Tamura潮波表计算的重力固体潮理论值残差RMS值为2.2 μGal.利用SSA提取的零点漂移值与最小二乘拟合得到的结果基本一致,十天内的差值小于0.4 μGal/d.