Protection by iron salts against sporidesmin intoxication in sheep

A number of iron compounds have been shown to protect sheep against the harmful effects of the facial eczema toxin, sporidesmin. Various salts were found to be effective; the oxidation state of the metal was not important although water-solubility did appear to be a prerequisite for prophylactic activity. The effect of iron salts was additive with that of zinc, and it is suggested that the protective action of these compounds results from their ability to inhibit the absorption of copper, consistent with the previously-proposed freeradical mechanism for sporidesmin toxicity.     

Testing genetic determinism in rate of hoof growth in pigs using Bayes Factors

Excessive growth and consequent deformity of hooves is a frequent disorder in some purebred pig populations. A test to detect possible genetic determinism related with this phenomenon was performed using the Bayes Factor (BF). Data were available for females from three purebred selection lines: Landrace (561 records), Pietrain (183) and Large White (225). Animals were scored in four categories, according to the overall growth rate of their hooves. A Bayesian analysis was performed separately for each line using a threshold model with a probit approach, and Bayes Factors between models with and without additive genetic effects were computed. Results from the three lines showed that models exhibiting genetic variability were much more probable than those that did not include a genetic component, with BF values of 312, 35 and 40 (and posterior probabilities of 0.99, 0.97 and 0.98), respectively, for the Landrace, Pietrain and Large White lines. Monte Carlo estimates of posterior means of heritabilities were medium to high (0.25, 0.41 and 0.38, respectively), and the highest posterior density region for heritability at 99% did not include zero in any of the three lines. These results allow us to conclude that genetic determinism has an important influence upon the rate of hoof growth in the pig. A potential genetic response can be achieved in the populations analysed, but further studies are needed to determine the genetic architecture of hoof growth disorders in pigs.     

模糊分类在土地利用/覆盖变更调查中的应用

模糊分类是近年来在遥感影像分类中引入的一种新的研究方法,是一种针对不确定性事物的分析方法。它以模糊集合论作为基础,运用数学模型计算它对于所有集合的隶属度,然后根据隶属度的大小,确定归属。笔者把“模糊分类”方法运用于吉林省白山市八道江区土地利用/覆盖变更调查中,从试验结果发现“模糊分类”在复杂地块影像分类中较传统的贝叶斯分类有更好的分类结果。     

基于Bayes判别分析法的密云县山洪泥石流预报模型

针对密云水库上游密云县境内山洪泥石流灾害多发的特点,首次将Bayes判别分析法原理运用于自然灾害的预测预报.运用系统科学和山洪泥石流预报原理,对密云水库上游密云县境内影响山洪泥石流发生的系统内部要素和系统外部环境条件进行分析,确定用影响山洪泥石流发生的前15 d的实效雨量和当日雨量作为预报模型因子,并建立起一组山洪泥石流预报模型,经自身验证法和交互验证法对模型进行检验,其判断正确率均为82.4%,达到了Bayes判别分析要求的判别模型自身验证正确率>80%的要求,两种方法检验结果一致,模型表现稳定,表明所建立的模型可靠,可以投入使用.研究结果可为该地区的山洪泥石流预测预报提供一种较为简单易行的方法,为密云县山洪泥石流灾害防治提供一定的支撑,以减少山洪泥石流发生所导致的灾害损失.     

民族旅游利益保障制度的伦理学反思——基于三大伦理学派对利益的分析

在民族旅游发展过程中,利益保障制度的缺失或是不合理已成为利益冲突频发却又不能得到合理、彻底解决的根源。全面了解三大伦理学派对利益、利益主体、利益冲突、利益协调的阐释,对于构建和调整民族旅游利益保障制度有深切意义。     

基于物联网的远程温室视觉监控系统设计与实现

在当前智慧农业的大环境下,农作物生长过程的识别与监控问题一直是一项具有挑战性的任务,基于此提出一种基于物联网的远程温室视觉监控系统,系统通过LoRa无线通信技术监测温室内的温湿度、光照强度等环境参数,能够及时监测到农作物的生长状况,并实现自动通风、自动补光等功能。在PC端的Qt上位机实时监测温室内的环境信息并控制环境参数,通过OV9726摄像头对农作物进行监测,所获得的生长状态信息传输到S3C6410集中控制模块进行处理,结合克隆选择算法和朴素贝叶斯分类器对叶片进行识别处理。本系统采用LoRa模块进行自组网来实现环境监测,将Linux操作系统移植到集中控制模块,为视觉系统软硬件平台的搭建做准备工作,所使用的组合算法能够使得农作物叶片识别率达到95.3%,识别时间达到8.4 ms,对于叶片识别精度等方面有着明显的提升,经过实验充分验证本系统所使用的设备与算法的有效性。     

Economic evaluation of forest drainage and fertilization in northern Ontario peatlands with an investment decision model

Drainage and fertilization of an existing peatland black spruce (Picea mariana (Mill.) B.S.P.) stand and 24 possible methods of planting a clear-cut area near Cochrane, Ontario were evaluated by means of a recently developed forestry investment decision model, FIDME.Results indicate that, on the basis of the cost estimates used and assumptions made, drainage of the existing stand is the most economical treatment if it can reduce the rotation age by 30 years or more. Drainage combined with fertilization is the second best alternative if this treatment can reduce the rotation age by 40 years or more. Fertilization of the undrained site ranks a distant third, and then only if it reduces the rotation age by 10 years; otherwise, it will be uneconomical to apply.In the case of the clear-cut area, planting bare-root stock on a mechanically prepared but undrained site without weed control ranked first among the 24 alternatives considered; the same treatment, but with weed control included, ranked second. Planting containerized seedlings on a mechanically prepared but undrained site with weed control ranked third, followed by planting bare-root stock on a mechanically prepared and drained site with weed control. In contrast, planting containerized seedlings on an unprepared site and with no weed control ranked as the least cost-effective method considered.     

非瞬时或突变的马尔可夫链的一种应用方法

介绍对于一种非瞬时或突变的状态转移过程.采用Bayes方法修订马尔可夫过程的状态转移概率矩阵;将先验概率分布修订为后验概率分布;对整个过程的信息加以吸收,得出能够反映整个过程的状态转移概率矩阵,从而达到预测目的.由此还得出一个重要结论:吸收信息的无序性.     

浅析当代大学生的主观幸福感

培养当代大学生的主观幸福感是大学生心理健康教育的重要内容。本文就主观幸福感的概念、影响大学生主观幸福感的因素及培养的方法进行论述。     

基于相关性阈值的NSCT图像去噪方法研究

利用非下采样Contourlet变换（NSCT）平移不变性、多分辨率、多方向的优点,提出一种基于尺度相关与阈值去噪相结合的非下采样 Contourlet变换图像去噪方法。首先对噪声图像进行非下采样Contourlet变换,得到各个尺度各个方向子带的系数,然后采用相关系数归一的方法,结合Bayesian自适应阈值来达到更好的去噪效果。仿真实验表明,该方法在提高去噪后图像的峰值信噪比的同时,有效保留了图像的纹理信息,避免伪吉布斯现象,改善了图像的视觉效果。