转基因食品消费者认知与政府规制问题研究综述

通过对近期相关文献的整理分析,从转基因食品消费者态度及影响因素、转基因食品标识与风险交流等政府规制方面进行综述,以明确国内外研究差距及进一步研究方向。     

A method for calculating the motion angle of linkagesusing magnetometers and accelerators

To describe the motion state of multi joint linkage in series transformation, a method to solve the motion state and attitude position by measuring the magnetic induction density and acceleration is studied. The angle calculation is performed by employing the direction cosine transformation between the geographical coordinate and the basic coordinates of the magnetic and gravitational fields of the earth. The mode of the attitude angle, denoted by the magnetic induction density and acceleration, is obtained. The angle transformation during the coordination transformation is analyzed. The relationship between attitude angle of the linkage and the angle of the linkage in the series transformation is deduced. An example is used to verify the model. This model can solve the transformation problem between attitude angle and real angle, which is the same as the motion expression of the body.     

模拟复杂地形的喷雾靶标激光检测与三维重构

喷雾靶标的检测是精密变量喷雾的重要环节,激光传感器以其精度高、速度快、不受光照干扰等特点被广泛应用于精密变量喷雾研究中。为了消除激光传感器姿态角的偏移对喷雾靶标检测的影响,获取精确的喷雾靶标外形尺寸信息以及三维重构图像,进行了室内模拟复杂地形激光检测矫正研究。该文基于UTM-30LX型激光传感器搭建了室内靶标检测试验平台,模拟复杂路况设计了滚转角、俯仰角和偏航角等姿态角偏移检测试验,提出了采用极坐标值与三角函数重新匹配、检测帧与检测点重新组合和深度值系数矫正等3种姿态角偏移矫正方法。首先对树形雕花板进行单一姿态角偏移检测试验,选取适合的检测距离与行进速度,对每种姿态角的多个偏移角度进行多次重复试验,然后矫正所获取的数据信息,对矫正后的目标尺寸进行误差分析并重构目标三维图像。再以仿真树为试验对象,验证在3种姿态角度同时改变时矫正方法的有效性。试验结果显示树形雕花板高度、宽度、树冠高度等尺寸相对误差均小于5%,仿真树相应参数尺寸相对误差均小于10%,满足变量喷雾检测的精度要求。     

A multidisciplinary approach to determine factors associated with calf rearing practices and calf mortality in dairy herds

In the Netherlands, an increase in ear-tagged calf mortality (3 days to 1 year of age) in dairy farms was observed. The aim was to determine why calf mortality increased and how to reduce calf mortality in herds with structural high rates.     

加强农业科研院所一流作风建设的几点思考

文章探讨了新形势下农业科研院所作风建设的重要性及存在的问题,从思想、发展理念、制度建设和责任意识四个方面分析了原因,并针对问题提出了保障农业科研院所一流作风建设的对策与建议,如强化思想引导与教育,搭建学习平台,形成强大工作合力;推进事业单位分类改革,构建院所创新机制,营造科学高效的创新氛围;加强创新文化建设,实现资源合理配置,创造优质科研工作环境;加快现代院所制度建设,不断健全完善现有制度,构建完善的管理制度体系等。     

高校特困生管理工作之我见

随着我国高等教育招生，收费制度改革的不断深入，家庭经济确有困难的学生能否顺利完成学业，已引起社会各界的普遍关注。对于这一特殊群体，高校应积极采取政策和措施，帮助特困生完成学业，使他们在困境中得以生存和发展。     

双矢量定姿算法提高海参捕捞装置捷联惯导系统粗对准精度

针对传统解析粗对准算法中水平对准精度同时受陀螺仪和加速度计测量误差影响的问题,提出一种双矢量定姿粗对准算法,该算法在选定重力矢量为主参考矢量的前提下,预先对参与姿态解算的矢量作单位正交化处理。理论分析表明,所述算法使得水平对准精度只受加速度计水平测量误差影响,提高了捷联惯导系统粗对准精度;实测数据的试验结果表明,所述粗对准算法的水平误差角的大小不超过1°,方位误差角的大小不超过3°,在粗对准所要求的误差范围之内,为后续利用滤波方法进行精对准提供了有效的初始条件。     

融合激光三维探测与IMU姿态角实时矫正的喷雾靶标检测

基于高精度激光传感器的喷雾靶标特征检测是精准施药变量决策的重要依据。为了改善复杂地形条件对车载激光靶标检测的影响,进行了车载激光喷雾靶标检测与矫正研究。该文基于惯性测量单元(inertial measurement unit,IMU)与UTM-30LX型激光传感器搭建靶标检测试验车,IMU实时获取车体姿态角的偏航角、俯仰角及侧倾角信息,车载激光传感器实时获取目标切面轮廓的极坐标数据。将获取的目标切面轮廓的极坐标数据与试验车姿态角信息相匹配,通过矫正算法获取精确的目标外形尺寸信息并重构目标三维图像。试验设计首先对长方体柜子与仿真树进行车体单一动态俯仰角的检测试验,然后以仿真树为试验目标,进行车体存在复合动态俯仰角与侧倾角的检测试验,最后在未知地形条件下对长方体柜子以及仿真树进行动态姿态角检测与矫正试验。利用MATLAB软件对数据矫正分析,对矫正后的目标尺寸信息进行误差分析并重构目标三维图像。试验结果显示矫正后长方体柜子的高度、宽度最大相对误差分别为8.89%和8.00%,仿真树的高度、宽度以及树冠高度最大相对误差分别为5.63%、10.00%和5.00%,矫正效果良好,验证了矫正算法的有效性。     

Factors influencing hybrid maize farmers' risk attitudes and their perceptions in Punjab Province,Pakistan

Hybrid maize farmers have to face diverse kinds of climate, biological, price and financial risks. Farmers' risk perceptions and risk attitudes are essential elements influencing farm operations and management decisions. However, this important issue has been overlooked in the contemporary studies and therefore there is a dearth of literature on this important issue. The present research is therefore, an attempt to fill this gap. This study aims to quantify hybrid maize farmers' perceptions of disastrous risks, their attitudes towards risk and to explore the impacts of various farm and farm household factors on farmers' risk attitudes and risk perceptions. The present study is conducted in four hybrid maize growing districts of Punjab Province, Pakistan, using cross-sectional data of 400 hybrid maize farmers. Risk matrix and equally likely certainty equivalent (ELCE) method are used to rank farmers' perceptions of four catastrophic risk sources including climate, biological, price and financial risks and to investigate farmers' risk aversion attitudes, respectively. Furthermore, probit regression is used to analyze the determinants affecting farmers' risk attitudes and risk perceptions. The results of the study showed that majority of farmers are risk averse in nature and perceive price, biological and climate to be potential sources of risks to their farm enterprise. In addition, analysis divulges that distance from farm to main market, off-farm income, location dummies for Sahiwal and Okara, age, maize farming experience, access to extension agent, significantly (either negatively or positively) influence farmers' risk attitudes and risk perceptions. The study delivers valuable insights for farmers, agricultural insurance sector, extension services researchers and agricultural policy makers about the local understanding of risks to hybrid maize crop in developing countries, like Pakistan, and have implications for research on farmers' adaptation to exposed risks.