农业院校学生农村就业的利与弊

在当今社会竞争如此激烈的大环境下,高校毕业生的规模又如此的庞大,就业的压力越来越大,有一种呼声:农业院校的毕业生到农村就业是唯一途径,这种声音普遍受到社会和人们的关注。其实现在的农业院校并非以前仅仅是农业专业,因经济全球化的快速发展让农业院校在专业方向的建设上也开始多元化。再且,由于现在的毕业生都是80后、90后,去农村就业有利有弊,所以农村并不是农业院校毕业生的唯一出路。     

生态旅游社区从事旅游业者的行为特征研究——以芦芽山自然保护区为例

生态旅游社区从事旅游业不仅是保护自然资源的坚强力量，而且是支持旅游业的主力军，他们是旅游影响的直接主要的承受，本采用问卷调查的方式，对芦芽山自然保护区从事旅游业的行为特征进行了调查，结果表明，社区人们对自然保护的支持率较高，但却认为可以私自利用其资源，他们对于旅游的各种影响反映良好。     

Handling of Environmental and Biological Samples via Pre-Column Technologies

Abstract

Sample handling is still a weak point in chromatography and in analytical chemisty in general. One consideration is the automation potential of new procedures. Solid-liquid extraction techniques in combination with pre-column technology are particularly promising in this regards. The construction and geometry of pre-columns both for conventional and narrow-bore HPLC are of major importance, since band broadening should be kept at a minimum for an optimal functioning of the analytical system. The various operations that can be carried out with such a pre-column are trace-enrichment, clean-up of the sample which depends on the type of adsorbents used in the precolumn, i.e., polar or apolar materials, ion exchangers or metal covered surfaces, etc., protection of the analytical column, field sampling and storage of samples and as a substrate for on-column chemical derivatizations. These various operations are demonstrated with practical examples from the fields of environmental and biological analysis. The selectivity can be further enhanced by coupling precolumn technology with selective detection modes such as diode array UV, electrochemical or fluorescence detection. This enables the construction of optimal and integrated analysis sytems which are fully automated and microprocessor controlled. They can also be made compatible with miniaturized LC-technology.     

对“四舍六入五留双”修约规则的商榷*

数值修约是分析化学教学的重要内容。目前,主流分析化学教材均采用 “四舍六入五留双”数值修约规则。详细剖析了该规则中尾数与进舍条件的关系,指出“四舍六入五留双”修约规则中应采用“尾数的首位”而不是“尾数”设置进舍条件,否则存在逻辑错误。对比分析表明,“四舍六入五留双”以数字4、5和6为比较值设置的修约规则等价于GBT8170—2008国家标准中以数字5为比较值设置的进舍规则,但GBT8170—2008国家标准的进舍规则的逻辑、表述等优于“四舍六入五留双”规则。因此,建议分析化学教材采用GBT8170—2008国家标准规定的数值修约相关内容。     

Inorganic Elements in Mytilus galloprovincialis Shells: Geographic Traceability by Multivariate Analysis of ICP-MS Data

The international seafood trade is based on food safety, quality, sustainability, and traceability. Mussels are bio-accumulative sessile organisms that need regular control to guarantee their safe consumption. However, no well-established and validated methods exist to trace mussel origin, even if several attempts have been made over the years. Recently, an inorganic multi-elemental fingerprint coupled to multivariate statistics has increasingly been applied in food quality control. The mussel shell can be an excellent reservoir of foreign inorganic chemical species, allowing recording long-term environmental changes. The present work investigates the multi-elemental composition of mussel shells, including Al, Cu, Cr, Zn, Mn, Cd, Co, U, Ba, Ni, Pb, Mg, Sr, and Ca, determined by inductively-coupled plasma mass-spectrometry in Mytilus galloprovincialis collected along the Central Adriatic Coast (Marche Region, Italy) at 25 different sampling sites (18 farms and 7 natural banks) located in seven areas. The experimental data, coupled with chemometric approaches (principal components analysis and linear discriminant analysis), were used to create a statistical model able to discriminate samples as a function of their production site. The LDA model is suitable for achieving a correct assignment of >90% of individuals sampled to their respective harvesting locations and for being applied to counteract fraud.     

安徽省全民健身活动现状与发展对策的调查研究

而今在伴随着不同经济角色分化的市场经济时代,健身娱乐活动的服务性,因利益体现和交换的社会化要求而被置换成一种“服务与消费”的产业性行业已是不争的现实.那么,安徽省全民健身活动现状与发展究竟怎样?笔者试对健身娱乐业的产业结构、产品结构、市场份额等做了一定层面的审读,梳理出若干结论并提出了一定的对策建议.     

基于模糊综合评价的基本功能岸段划分方法研究

基本功能岸段划分涉及的因素很多,诸多因素错综复杂.为避免功能岸段划分的主观性,以辽宁省基本功能岸段划分为例,从海岸自然环境特征、海岸开发利用现状、海岸资源社会经济需求和相关的海洋功能区划/规划等方面构建了基本功能岸段综合评价指标体系,建立了以模糊综合评价方法为主体的海岸基本功能综合评价方法,并采用GIS技术实现了评价过...     

河南省体育课程自然地理资源的开发与利用

通过对河南省自然地理资源的分析,结合学校体育课程理论,采用文献资料、问卷调查,数理统计等方法对河南省体育课程和社区体育自然地理资源的开发与利用进行分析.结果表明：虽然河南省地域辽阔,有着千姿百态的地况地貌,气象万千的季节气候,但是,各地政府和学校开发和利用自然地理资源严重不足.因此,各地政府和学校领导人员应该结合本地的实际情况,从实际出发,坚持安全环保原则,确保自然地理资源能够合理有效的开发利用.     

中国东盟国际口岸空间运输优化布局研究

随着区域经济合作与经济全球化的发展,中国加强与东盟经济合作势在必行.以云南省的16个国家口岸为研究对象,深入分析了口岸运输的分布及其交流特征,指出了口岸运输现状中存在的主要问题.运用首位联接强度模型,计算了口岸间的联系度,据此将口岸区域空间组合划分为中缅、中越两大系统,得出了优先发展区域,为云南省"桥头堡"和"沿边开放开发试验区"的建设与实施提供参考.     

基于神经网络方法的湿地生态脆弱性评价

应用BP神经网络模型对扎龙湿地的生态脆弱性进行了评价.采用7-2-4-1结构,以计算得到的各湿地类型样本栅格单元生态脆弱指数EⅥ值作为训练集,通过最大1 000次的误差反向传播训练,获得的最大误差是1.1%,最小误差0,成功实现了扎龙湿地7维评价指标变量到1维变量即扎龙湿地生态脆弱性指数的映射,得到了研究区全部栅格单元...