Disease at the wildlife-livestock interface: Acaricide use on domestic cattle does not prevent transmission of a tick-borne pathogen with multiple hosts

Several prominent and economically important diseases of livestock in East Africa are caused by multi-host pathogens that also infect wildlife species, but management strategies are generally livestock focused and models of these diseases tend to ignore the role of wildlife. We investigate the dynamics of a multi-host tick-borne disease in order to assess the efficacy of tick control from an ecological perspective. We examined the efficacy of a widespread measure of tick control and developed a model to explore how changes in the population of ticks due to control measures on cattle impact dynamics of Theileria parva infection in a system with two primary host species, cattle and Cape buffalo (Syncerus caffer). We show that the frequency of acaricide application has a significant impact on the tick population both on the host and in the environment, which can greatly reduce the pathogen load in cattle. We also demonstrate that reducing the tick population through cattle-related control measures is not sufficient to diminish disease transmission in buffalo. Our results suggest that under current control strategies, which target ticks on cattle only, T. parva is likely to remain a significant problem in East Africa, and require the continued use of acaricides, which has significant economic and ecological consequences.     

能源与农业价格传递分析

运用协整分析、向量自回归、误差修正模型和脉冲响应的方法,详细研究中国从2000年1月至2004年10月新的一轮原油价格上涨之后,月度原油现货价格和生产资料以及生活资料各部分(包括食品、服装、一般日用品、耐用消费品等)尤其是农副食品链之间的价格传导关系。研究结果表明,我国原油价格的传递在上游生产资料产品中显著且滞后期较短,在中游和下游生活资料的传递不畅通且影响的滞后期比较长。     

Prediction and Analyses of Residual Chlorine Based on Support Vector Regression in Urban Water Distribution System

Support vector regression(SVR) algorithm is an application of structural risk minimization principle in function regression.In this paper,a residual chlorine prediction model based on SVR is established by using the data of manual sampling residual chlorine of water distribution system in a certain city in the north of China.SVR model is compared with the artificial neural network and multivariate linear regression.The result shows that SVR model has better generalization ability for small samples,the predicted average relative error of all monitoring points is 1.80%~8.73%,and can achieve unique and globally optimal solutions.It is practical and can solve the problem for small samples of residual chlorine when the fit precision of model is good but the predicted effect is worse.     

基于高光谱遥感数据的森林优势树种组识别1）

本文利用HJ－1A星HSI2级产品数据对大兴安岭塔河地区的森林优势树种组进行识别研究。通过对影像数据进行一阶微分变换、对数变换、对数变换后的导数变换、二阶微分变换、三阶微分变换以后,分别对原始数据和5种变换后数据进行MNF（最小噪声分离变换）变换。用SVM（支持向量机）分类器分别对6种数据监督分类后,进行精度的验证及评价。结果表明：影像数据经过5种变换后,分类总精度均高于未经变换的原始数据,精度提高幅度为1．5％～4．8％,二阶微分变换分类精度最高（精度为89．5％,Kappa系数为0．802）;二阶微分变换下的4个优势树种组各自的制图精度和用户精度均高于其他变换方法,平均精度分别为90．4％和90．7％,总平均精度为90．5％。     

猪白细胞介素-2基因的克隆及其重组禽痘病毒载体的构建

采用RT-PCR技术自豫南黑猪脾淋巴细胞中扩增猪IL-2基因(pIL-2),RT-PCR产物进行T-A克隆并测序,获得了猪IL-2基因序列.将BamH Ⅰ酶切的猪IL-2基因非定向克隆到BamH Ⅰ酶切并去磷酸化的pSY538载体上,通过PCR、酶切和测序鉴定,筛选正向插入的重组质粒pSY538/pIL-2.NotⅠ酶...     

板栗疫病菌绿色荧光与红色荧光蛋白共定位载体的构建

低毒病毒-板栗疫病菌组合是研究病毒与宿主相互作用的一个优秀的模式系统。我们构建了含绿色荧光蛋白基因gfp的载体pCPXHY2GFP与含红色荧光蛋白基因rfp的载体pCPXG418RFP,并用于转化野生型菌株EP155,获得了以潮霉素为筛选标记、表达绿色荧光蛋白的转化株pCPXHY2GFP/EP155和以G418为筛选标记、表达红色荧光蛋白的转化株pCPXG418RFP/EP155。将载体pCPXG418RFP转化pCPXHY2GFP/EP155,获得的转化株能观察到绿色荧光蛋白与红色荧光蛋白共定位的现象。板栗疫病菌绿色荧光与红色荧光共定位载体pCPXHY2GFP与pCPXG418RFP的构建,为深入研究病毒与宿主相互作用的分子机制提供了强有力的研究材料。     

主因素分析方法及其实例

主因素分析方法是多元统计方法的一个新支,它在多种学科如气象学、经济学等都有成功应用的实例,但应用于栽培学,却遇到了困难,因为不好作出明确的生物学解释。近年来,有一些解决这一难题的方法,但只限于很特殊的情况。本文应用动态分析的方法,给出了一个在一般情况下都能应用的方法,并给出了一个说明性的实例。     

中国对虾（Penaeus chinensis）精子做载体将生长激素基因导入受精卵的研究

本实验采用卡介苗注射器将羊生长激素基因溶液注射到亲虾纳精囊中，以精子为载体，携带基因导入对虾受精卵，而达到转基因对虾的目的。经ＰＣＲ检测表明：１．经ＳＴＥ（ｐＨ８．０）第一次洗涤精子的洗涤液呈阳性信号；第２－４次的洗涤液呈阴性；２．多次洗涤后的精子抽提的ＤＮＡ呈阳性；３．检测 １０个样品１００尾仔虾中有一个样品呈阳性结果，转基因比率在 １％以上。同时斑点杂交结果也印证了上述结果。     

芸薹属DFR基因家族RNA干扰载体的构建

二氢黄酮醇-4-还原酶(dihydroflavonol-4-reductase,DFR)是类黄酮途径的一个关键酶,对种皮色泽和花色的形成具有重要作用。本研究从甘蓝型油菜克隆了600 bp(不计人工酶切位点)的芸薹属DFR基因家族的RNA干扰片段BDFRI,将其反义片段和正义片段分别插入到本课题组新近改造的植物RNAi平台载体pFGC5941M的启动子与间隔区之间、间隔区与终止子之间,构建了11 400 bp的RNAi干扰载体pFGC5941M-BDFRI,通过多重PCR鉴定证实载体构建成功,并转化到根癌农杆菌菌株LBA4404中形成了工程菌株。此载体的构建为进一步研究DFR基因参与决定芸薹属种皮色素和茎叶彩色性状的分子机理和代谢调控奠定了基础。     

基于支持向量机的重叠大豆颗粒计数

为了提高大豆千粒重的测定效率和精度,提出一种基于机器视觉的有效分割多层重叠颗粒和记数方法.将由摄像机采集的大豆颗粒图像经预处理后,提取所有的颗粒块区域;寻找颗粒块区域的拓扑形状特征欧拉数和形状特征向量:颗粒块轮廓边缘上凹点、颗粒块类圆近似核心;采用支持向量机分类法智能识别颗粒叠加类型,将其分为串重叠、多个并粘连和两层并重叠,最后实现自动分割.结果表明:该方法能有效解决两层重叠或深度粘连类圆大豆颗粒的准确计数.