六价铬对黄颡鱼仔鱼和稚鱼的急性毒性效应研究

利用静水式鱼类急性毒性测试法,分别以黄颡鱼（Pelteobagrus fulvidraco）仔鱼和稚鱼为受试对象,通过六价铬的急性毒性试验,获得24、48、72、96 h相应的半数致死浓度LC50值,比较了六价铬对黄颡鱼仔鱼和稚鱼的致毒敏感性,计算了六价铬对黄颡鱼的安全质量浓度并对六价铬对于黄颡鱼急性毒性等级进行了评价。旨在通过开展我国本土水生生物的急性毒性效应的研究,获得相应的毒理学数据,为推导符合我国生态分区特点的水质基准提供基础信息。结果表明,在水温为（23±2）℃条件下,六价铬对黄颡鱼仔鱼24、48、72、96 h的半数致死浓度LC50分别为28.32、21.99、17.70、15.79 mg.L-1,而对黄颡鱼稚鱼24、48、72、96 h的LC50分别为138.5、88.36、68.55、57.98 mg.L^-1,说明黄颡鱼仔鱼对于六价铬毒性的敏感性明显高于稚鱼。六价铬对黄颡鱼仔鱼和稚鱼的安全浓度分别为1.579、5.798 mg.L^-1,依据急性毒性结果和鱼类急性毒性分级标准,六价铬对于黄颡鱼毒性等级属于中等毒性。     

Responses to Selection against Clinical Mastitis in the Norwegian Cattle Population

The genetic trend for clinical mastitis was estimated for Norwegian Cattle, a population in which mastitis resistance has been included in the breeding programme since 1978. More than 1.2 million first-lactation daughters, with clinical mastitis records registered from 1978 to 1995, bred by 2043 sires, were analysed with a linear sire model. For bulls born from 1974 to 1990 a flat genetic trend for clinical mastitis was found. However, bull sires born from 1983 onwards, selected on a breeding goal with increased weight on mastitis relative to milk production, showed consistently larger and favourable selection differentials for mastitis relative to bull sires born earlier, which had an average selection differential of approximately zero. This will influence genetic trend in the population through their sons, which were born from 1990 onwards.     

Prevalence of clinical findings at examinations of young Swedish warmblood riding horses

Background

Soundness of an individual horse is important for animal welfare and owner economy. However, knowledge of health status in normal horse populations is limited due to lack of systematic health recordings. The aim of the investigation was to study the prevalence of veterinary clinical findings in 4-5-year-old Swedish warmblood riding horses, and their influence on overall health scores, where associations to future longevity has been indicated.

Results

The prevalence of clinical findings in 8,281 horses examined during 1983–2005 was studied according to a standardised protocol and related to overall health scores in linear statistical models. Effects of sex, age, examination event and changes over time were included. In total, 49% of the horses had clinical findings of medical health (MED), 42% in hooves (HOOF) and 74% of palpatory orthopaedic health (PALP). However, only 6%, 3% and 24% had moderate or severe findings, of MED, HOOF and PALP, respectively. Flexion test reactions were reported in 21% of the horses (5% moderate/severe), heavily influencing the overall score (H2). One fifth of these horses also had findings of unprovoked lameness while 83% had PALP findings (44% with moderate/severe findings). Acute clinical signs, i.e. heat or soreness, had a large influence on the H2 score but were rare, whereas more common clinical findings had smaller effects on overall health. Large variations in recorded health results were observed among events. A decrease in findings has occurred since 1983, in particular for PALP findings.

Conclusions

Results of occurrence and relevance of evaluated clinical findings could be used for advice on preventive actions to keep horses sound, and possibly for benchmarking, and genetic evaluation of health traits. The distinct effect of event on recorded clinical findings emphasises that further harmonisation of veterinary examinations are desirable.     

百两金药学研究概况

在广泛文献检索基础上,对百两金的种属、成分、药理和临床应用的研究进展进行综述,为进一步开发利用提供资料。     

山蚂蝗属植物药学研究概况

在广泛文献检索的基础上,对山蚂蝗属植物的成分、药理、临床应用及生态价值等进行概述,为进一步研究和开发提供科学资料。     

27个木槿品种的数量分类和主成分分析

通过观测27个木槿品种的17个数量和质量性状,探究了木槿品种分类的等级和标准,便于为木槿品种的选育与资源研究等提供参考依据。首先对17个性状指标进行R型聚类分析和主成分分析,根据分析结果再对27个木槿品种进行Q型聚类分析。R型聚类分析结果表明,各性状选取是合理的;主成分分析结果表明,17个性状可综合为6个主成分,其累计贡献率达88.096%。Q型聚类结果表明,27个木槿品种根据有无丹心、花型、丹心基部形状、花瓣指数、花径、叶形、丹心线与丹心的关系可被分为2大类、3大类或8大类。16个性状对木槿品种的划分贡献较大。综合而言,有无丹心、花型、花瓣指数、丹心线与丹心的关系是木槿品种分类的主要标准和依据。     

富士和嘎啦苹果叶片面积估算模型构建

【目的】建立准确、无损的适宜于苹果不同品种和枝梢类型的叶面积估算模型。【方法】以富士及嘎啦不同长度的营养枝梢和果台枝梢叶片为试材,采用数字扫描仪获取叶片长度(LL)、宽度(LW)和叶面积(LA)等叶片形态参数,并采用决定系数(R²)、均方根误差(RMSE)、赤池信息准则(AIC)对建立的17个有常数项和无常数项叶面积模型精度进行筛选和适宜性评价。【结果】共获得5 207枚叶片形态参数,其中叶面积变异系数最大,达51.59%。叶片形态受品种及枝梢类型的显著影响,其中长枝梢叶片长、宽和叶面积显著大于同类型短枝梢叶片,而营养枝梢叶片长、宽和叶面积显著大于同长度果台枝梢,嘎啦叶片相比富士更为细长。以LL和LW复合变量为自变量的模型5:LA=a(LL×LW)、模型6:LA=a(LL+LW)²、模型9:LA=aLL²+bLW²、模型16:LA=a(LL×LW)^b、模型17:LA=(LL×LW)^b的精度可满足富士和嘎啦各类枝梢叶面积的估算,但需针对各品种和枝梢类型单独建...