Double-outlet right ventricle in a 10-month-old Friesian filly

A 10-month-old Friesian filly had a presentation that was consistent with chronic left- and right-sided congestive heart failure. Clinical pathology findings included abnormal haematological and biochemical variables, abnormal blood gas values and increased serum concentration of cardiac troponin I. Echocardiography revealed cardiac chamber dilation and dextropositioning of the aorta. Radiography revealed a generally enlarged heart and pulmonary interstitial infiltration. These findings were supported at necropsy and the diagnosis of double-outlet right ventricle was confirmed. The pathological changes and physiological responses subsequent to double-outlet right ventricle have not previously been described in detail in horses. Clinical progression closely resembles that seen in humans, in whom antemortem diagnosis relies on echocardiography. In horses, complex cardiac disease presents a diagnostic challenge to the clinician. Appropriate therapy must be based on an accurate diagnosis.     

世界稀土资源现状分析与我国稀土资源可持续发展对策

稀土资源已成为21世纪全球现代工业化建设中不可或缺的因素,有着重要的战略价值。研究我国稀土现状,采取战略性的稀土保护策略对未来国内稀土产业健康发展具重要意义。本文介绍了世界稀土的现状和我国稀土资源概况,对比美、日、英、德等国的稀土战略政策,概括我国稀土资源管理中存在的问题及产生的原因,提出我国稀土战略可持续发展对策,并建议将稀土资源保护提高到国家战略的层次。     

右心下缘膨凸及帆状阴影诊断三尖瓣下移畸形的价值(附14例报告)

本文报道的14例三尖瓣下移畸形,表明右心下缘膨凸及帆状阴影是诊断该畸形的重要依据,并讨论了该诊断依据形成的机理。     

Limits to genetic rescue by outcross in pedigree dogs

Outcrossing should reduce inbreeding levels and associated negative effects in highly inbred populations. In this study, we investigated the effectiveness of different outcrossing schemes using computer simulations. The inbreeding rate estimated for a 25‐year period of 2.1% per generation in a highly inbred dog breed reduced to 1.8% when a single litter was produced by an outcross without backcrosses. To reduce the inbreeding rate below 1%, more than eight of the 14 litters born yearly in the recipient breed had to be outcrossed. However, outcrossing in pedigree dogs is usually followed by backcrossing and generally involves one or a few litters. Backcrossing reduced the effect of outcrossing considerably. When two litters were produced by an outcross followed by one generation of backcross, the inbreeding rate was 2.0% per generation. Continuously outcrossing was more effective than a single or a few outcrosses. When each newborn litter during 25 years had a 5% chance of being produced by an outcross, the inbreeding rate reduced to ?0.2%. To investigate the possibility that new alleles were introduced from the donor population into the recipient population, the fate of different type of alleles (varying from completely lethal to beneficial) before and after an outcross was investigated by first simulating 80 years of natural selection prior to the outcross and then different types of outcross. Because natural selection reduced the frequency of lethal alleles before outcrossing, the introduction of a lethal allele that was segregating in the donor breed but not in the recipient breed occurred rarely. Introduction of slightly detrimental alleles or neutral alleles occurred more frequently. In conclusion, outcrossing only had a limited short‐term effect unless repeated continuously. Nevertheless, it may help to buy time in which the population structure can be changed so that the effective population size increases.     

木板智能涂腻设备关键技术

为了实现木板表面缺陷的自动检测与修复,设计了一种可以自动控制的涂腻头结构和基于OPC的控制系统,构建了针对涂腻设备的计算机视觉系统。基于视觉系统获得的三维缺陷信息,研究了板材表面缺陷图像数据的提取和处理方法。介绍了如何将图像处理程序内置在VB编写的上位机控制程序中。分析了板材表面分区涂抹腻子的修复工艺。     

吉林省民营企业制度创新研究

分析了吉林省民营经济发展现状,归纳了其发展中存在差距和问题,探讨了其发展滞后的影响因素,提出了吉林省民营企业发展的制度创新思路。     

基于机器视觉的胡萝卜表面缺陷识别方法研究

胡萝卜在生长与收获运输过程中,不可避免会出现一些外观缺陷,缺陷胡萝卜的剔除是胡萝卜上市销售前的重要环节。目前缺陷胡萝卜主要依靠人工分选,具有分选标准不稳定、劳动强度大、成本高等缺点。为了快速、准确、无损地检测缺陷胡萝卜,将机器视觉技术引入到胡萝卜分选过程中,以提高分选准确率和效率。胡萝卜表面缺陷包括青头、弯曲、断裂、分叉和开裂等,缺陷特征互不相同,所以不同缺陷需要不同的检测算法。青头检测利用胡萝卜正常区域与青头区域的颜色差异实现,胡萝卜图像在HSV颜色空间下,利用统计方法确定青头区域H、S和V的判别阈值;弯曲、断裂和分叉识别是根据正常胡萝卜与缺陷胡萝卜之间的形状差异实现,凸壳算法、Hu不变矩和Harris角点检测算法分别用来检测胡萝卜弯曲、断裂和分叉缺陷;开裂检测则是利用胡萝卜正常与开裂区域的纹理差异实现,Sobel水平边缘检测算子、Canny边缘检测算子结合形态学操作实现胡萝卜开裂区域提取。结果表明青头、弯曲、断裂、分叉和开裂的识别准确率分别为100%、91.14%、90.57%、94.57%和95.45%,总体识别准确率达94.91%,满足胡萝卜在线分选精度要求。     

基于二维阈值向量的木材表面缺陷分割方法

根据木材表面缺陷图像的自身特点,提出了基于灰度—梯度二维阈值向量的缺陷区域分割方法。该方法以灰度—梯度共生矩阵为模型,通过计算基于灰度—梯度共生矩阵的二维熵并使边缘区域的熵最大化来选择二维阈值向量。该方法不仅利用了图像的灰度信息,也利用了图像的梯度信息。采用形态学运算对分割后的二值图像进行分割后处理,试验表明,分割效果良好。     

城市排水管道结构性缺陷及应对策略

指出了城市排水管道普遍存在各种病害和缺陷问题,直接影响了排水系统功能的正常发挥,对管网的检测与修复是管网运维管理的重要工作。以武汉市南湖汇水区排水管网结构性缺陷为例,对缺陷的主要成因归纳为施工质量、管材质量和资产维护管理3方面,提出了应对策略,具体为严控施工质量和验收环节、采用智慧水务技术、运用排水管道非开挖修复新技术、加大排水管道新产品研发力度、变被动管理为主动管理这5个方面。以供参考。     

基于分水岭算法的木材缺陷边缘检测

获取边缘图像的一种典型方法是利用梯度算法作用于图像,然后对得到的梯度图像做阈值处理,从而得到二值边缘图像.这种方法的缺点是很难选取适当的阈值.如果阈值选得太低,不但会产生假的边缘,而且得到的边缘很厚,必须做细化处理,而细化后的边缘位置往往不是很精确;如果阈值取得太高,许多边缘可能检测不到,或边缘出现过多的断裂部分.