Yield stability and population diversity in oats (Avena sp.)

Summary The relationship between yield stability and populations containing various numbers and combinations of diverse homozygous and homogeneous lines was examined in an environment in which considerable variability occurs among and within growing seasons. Two groups (1,2), each containing 15 populations (4 pure lines grown singly and 11 multilines consisting of mechanical mixtures of all possible 2,3 and 4 way combinations of these 4 pure lines) were tested in each of 5 consecutive years. The pure lines in group 1 and 2 were selected on the basis of previous yield and yield variability respectively. In group 1, no significant differences were found among the 5 year means or the deviation mean squares of the 15 populations but highly significant differences among regression coefficients were present. The regression coefficients of the 4 pure lines differed considerably, indicating that this stability parameter was genetically influenced. The regression coefficients of the multilines tended towards unity regardless of the regression coefficients of the pure lines involved. In group 2, highly significant differences were found among the 5 year means, regression coefficients and deviation mean squares of the 15 populations. No consistent, predictable pattern was apparent between the mean and stability values of the pure lines and the multilines in which they were included. Differences between the 2 groups suggest that higher yield and greater stability result in the multilines if relatively high yielding pure lines are selected for inclusion. In general, the results indicated that multilines containing a number of diverse homozygous and homogeneous pure lines have satisfactory yields and enhanced yield stability. However, adequate testing of the pure lines and potential multilines over a broad range of environments is essential to determine desirable combinations.     

猎豹生理生化指标的测定

猎豹 (Ａｃｉｎｏｎｙｘｊｕｂａｔｕｓ )属食肉目、猫科、猎豹属 ,为大型食肉动物 ,原产于非洲草原 ,数量稀少 ,属《濒危野生动植物物种国际贸易公约》 (ＣＩＴＥＳ)附录Ⅰ动物。上海野生动物园于 1997年首次在国内繁殖并人工哺育成功这一珍稀动物 ,繁殖的 11只猎豹全部成活。现已有 2 0只 ,形成一较大的猎豹种群。有关猎豹的生理生化指标报道很少 ,而动物的生理生化指标是反映其机体状况的重要指标 ,也是实验研究的基础资料 ,更可为猎豹的驯养、繁殖及疾病诊治等提供重要的参考资料。为此 ,我们对本园 2 0只猎豹 (其中成年 9只 ,幼年 11只…     

Production costs,economic viability,and risks associated with compost bedded pack,freestall, and drylot systems in dairy farms

The adoption of intensive production systems, such as compost bedded pack (CB) and freestall (FS), has increased recently in tropical regions, mainly replacing the drylot system (DL). Thus, our objectives were to compare production costs, economic outcomes, and risk of dairy operations in CB, FS, and DL systems. We collected data from 2 181 Brazilian farms over 120 consecutive months; 960 farms (144 CB, 133 FS, and 683 DL) met our selection criteria. All costs were modeled for two animal production categories: milking cows and non-milking animals. We used a regression model that included linear and quadratic parameters, and we added the production system as a fixed variable for all parameters tested with this model. Consultant, year, herd, and herd × system interaction were included in the model as random variables. Further, we simulated annual technical and economic indexes per farm. In addition, we developed a risk analysis to measure the probability of negative profit of the farms based on a 14-year historical series of milk prices. All production costs were affected by the system. Feed, medicine, sundry, and labor costs per farm per year were greater in DL farms when milk yield (MY) was greater than 3 500 L/day. The variables such as milk yield, assets per liter, asset turnover rate, return on assets, operational profit, profit per cow, and per liter of milk variables were greater in CB and FS with high MY (>3 000 L/day). Nonetheless, DL had the greatest economic indexes with a lower MY (<3 000 L/day), lower operating costs, and greater economic outcomes. The risk analysis indicated that the probability of negative profit (risk) was reduced for CB and FS as MY increased, but DL had the lowest risk with low MY levels. In conclusion, we suggest DL as the most attractive system for farms with MY between 150 and 3 000 L of milk/day as the DL had the lowest risk and the greatest profit in this production scale. Despite similar outcomes for CB and FS in most of the farms, the profit per cow ($/year), assets turnover rate (%), risk (%) and expected profit ($/L) analysis indicated that CB could be recommended for farms with MY greater than 3 200 L of milk/day, whereas based on risk (%) and expected profit ($/L), FS would be the most profitable system in dairies producing more than 8 000 L of milk/day per farm.     

适应白洋淀湿地健康评价的IBI方法

IBI指数法是美国湿地生态系统健康评价的常用方法之一,在国内应用较少,目前为止只有少数学者尝试了底栖动物完整性指数(B-IBI)和鱼类完整性指数进行河流生态系统健康评价。试图建立适合白洋淀地区的生物完整性指数湿地健康状况评价的方法。在白洋淀的23个淀区进行土壤、水体、植物的实地调查与采样分析。根据已有研究所选择的植物属性,选择了30个植物属性作为备选参数。通过考察备选参数与人类干扰的相关性,最后确定了9个对人类干扰敏感的IBI参数。通过分析,建立了适合白洋淀湿地健康评价的标准:IBI,35-45,好;27-34,一般;19-26,差;＜18,极差。评价结果表明,白洋淀23个淀区中,6个健康状况好,5个一般,7个差,5个很差。     

短途运输应激对Wistar大鼠的影响

目的研究短途运输应激对Wistar大鼠的影响,建立评价啮齿类实验动物短途运输应激的技术指标体系。方法采用Wistar大鼠进行短途运输实验,测定其在运输中及运输后各阶段的代谢、神经内分泌和免疫功能主要指标,与未经历运输的对照组比较,分析短途运输应激的影响。结果Wistar大鼠血糖（GLU）在运输0.5 h和1 h时均升高,而在运输1.5 h时降低,运输结束后24 h时GLU再次升高;血清皮质酮（CORT）亦在运输0.5 h和1h时升高而运输1.5 h时降低,但运输结束24 h起即恢复正常;血清β-内啡肽（-βEP）从运输起至运输结束24 h时均降低,至48 h恢复正常。外周白细胞总数（WBC）自运输起急剧减少,于结束运输后的72 h恢复;免疫球蛋白G（IgG）、白介素2（IL-2）、γ干扰素（IFN-γ）及白介素1（IL-1）的血清水平在运输中及运输结束的即刻均没有显著变化,但在结束运输后的48 h内均不同程度降低,至72 h恢复至正常水平。肝脏hsp72 mRNA的表达随着运输时间的延长而极显著上调,运输结束后逐渐恢复,至72 h恢复至正常水平。结论短途运输应激对Wistar大鼠的代谢、神经内分泌和免疫功能均有不利影响,其经历常规短途运输（1.5 h以内）到达目的地后的健康适应期至少应为72 h;外周血中白细胞总数（WBC）、血糖（GLU）、皮质酮（CORT）、β-内啡肽（-βEP）、白介素2（IL-2）的水平可用于系统评价短途运输应激。     

Evaluation of models capacity to predict size spectra parameters in ecosystems under stress

Size spectra are important indicators of biomass distribution, for fundamental understanding as well as for application in management. While many size spectra models have been developed, it is unclear how response to stress varies across models and in comparison to data. In the present study, we therefor collected papers on empirical size spectra in stressed aquatic ecosystems and compared the results to theoretical models’ predictions from literature. A general decrease of the slope, as suggested by most of the studied models, is supported by the data found. The investigated empirical studies revealed a strong trend for the slope: 40 out of 57 studies reported a decrease with stress. Deviations from the linear model increased in 10 out of 20 cases and the intercept became larger in 25 out of 43 cases. The data concerning specific impact drivers is generally consistent and supportive of current expert opinions. Our results support that an integration of deviation from the linear model and intercept in the size spectra models could provide better coupling between modeling and field surveys for some stressors.     

高级护师综合评价指标体系研究

目的:结合当前我国护理事业发展规划纲要、人事制度改革、岗位评聘的需要,构建科学合理、实用性强的高级护师综合评价指标体系,实现对高级护师科学化的综合评价。方法:运用文献分析法及专家访谈法建立备选评价指标,据此对39名专家仅进行三轮专家咨询。通过德尔菲法对拟定的指标进行筛选和补充,通过层次分析法对指标权重进行明确。结果:经过三轮专家咨询及数理统计分析,构建了一套科学的三级甲等综合性医院高级护师综合评价指标体系。该指标体系包括职业素质、学识水平、业务能力、工作业绩4个一级指标及其延伸的12项二级指标和47项三级指标。结论:本研究构建了科学、实用的高级护师综合评价指标体系,该指标体系层次分明、指标数量适中、指标权重明确,有利于正确反映高级护师实际能力和综合素质,能够对高级护师进行科学的的综合评价。     

Does variation of sex ratio enhance reproductive success of offspring in tawny owls (Strix aluco)

Tawny owls, Strix aluco, laid female-biased clutches on territories with more abundant prey (field voles) in June, the month that chicks fledge. This appeared to enhance the subsequent reproductive success of fledglings, as in 1995 there was a significant correlation between the number of chicks fledged by adult females and the June vole abundance in the territory on which they were reared as chicks. This relationship did not hold for males. Since tawny owls lay eggs in March, these results indicate that owls are able to predict the June vole numbers on their territory, and respond by producing more of the sex most likely to gain a long-term benefit when resources are good.