Acoustic evaluation of the vertical distribution of dwarf ayu Plecoglossus altivelis altivelis in Lake Biwa

SUMMARY: The vertical distribution of dwarf ayu Plecoglossus altivelis altivelis in the pelagic waters of Lake Biwa was evaluated from June to September in 1995–97 from eight acoustic surveys using a quantitative echosounder. In each survey, echoes from a depth range of 3 m to the sea bottom were collected at a station every 2.7 s for 24 h together with measurements of vertical profiles of water temperature and chlorophyll-a. The ayu's echoes were identified using an underwater video camera. The ayu were observed near the maximum chlorophyll-a depth and above the thermocline. Their density was highest at depths of 4–11 m with 2–4 individuals/m ³ and was almost zero below 20 m. Echo signs were recorded as having a frequent duration of more than 1 h at night, whereas were of a shorter duration in the day. The fish stay in the epilimnion during the day without any clear vertical migration, but are distributed more uniformly at night. The advantages of remaining in the epilimnion are discussed in terms of food availability and predator avoidance.     

An evaluation of the Olsen test as a measure of plant-available phosphorus in grassland soils derived from basalt parent material

Abstract. Anecdotal and circumstantial evidence have suggested that the Olsen test underestimates plant-available phosphorus (P) in basaltic soils in Northern Ireland. Therefore, the ability of this test to predict plant-available P in basaltic (and non-basaltic) soils was investigated by regressing Olsen-P data against herbage P indices calculated from plant tissue test data using the diagnosis and recommendation integrated system. The average Olsen-P concentration for a range of fields situated on basaltic soils was considerably lower than the average Olsen-P concentration for a range of fields situated on non-basaltic soils, and yet mean sward P status, as given by the herbage P indices, was similar for both groups of fields. Herbage P indices were also much better correlated with Olsen-P measurements in non-basaltic soils than in basaltic soils. Furthermore, at low Olsen-P values (≶9mgPL⁻¹) some swards on basaltic soils were genuinely deficient in P, while others were sufficient or even in surplus for this nutrient. The results confirm that Olsen-P is inadequate as a predictor of plant-available P in basaltic soils. It is concluded that an alternative soil test is needed to provide a reliable assessment of plant-available P in basaltic soils, to prevent overuse of fertilizer and manure P and to minimize the amounts of P entering local watercourses.     

运用模糊数学和灰色系统理论分析评价夏播花生区试品种

运用模糊数学和灰色系统理论，对2007年河南省夏播花生区试品种进行了多因素综合评价和分析，结果表明：周花4号评价指标是0．7089，综合表现最优；其次是W9847—1—3—4—1，其综合评价指标是0．6352；豫花6号评价指标是0．3630，综合表现最差。此结果与试验地实际表现基本相一致。     

祁连山水源涵养林综合效能的计量研究

以马克思级差地租理论,建立了祁连山水源涵养林综合效能的评价模型:E=E_d+E_e+E_s;以E与生产投资I的比值为计量水源林的效能指数T,T=E/I。并以祁连山寺大隆森林生态定位研究站实测资料和社会调查数据为计量评价参数,确定其经济评价指标体系和计量系统。结果表明:祁连山水源涵养林综合效能指标为11.93;其中生态效能和社会效能分别是直接经济效能的4.51倍和6.05倍。说明祁连山水源涵养林现行的保护、发展和综合利用的经营方针是正确的。建议河西各受益部门应按水资源效能总收入的0.5％缴作水源林再生产费,以确保国民经济建设的长远发展。     

不确定度评定方法在汽车事故再现中的应用

介绍了不确定度理论及其评定方法，结合车辆碰撞事故的具体特点，给出了基于能量守恒的车速计算表达式．通过选择适当的输入参数作为不确定因子，分别计算各分量等效速度标准不确定度．考虑不确定度累积和传播，得到车速输出结果的合成标准不确定度和展伸不确定度，以此检验事故再现结果的准确程度．通过具体事故案例的分析计算和计算机检验，验证该方法的适用性．     

模糊评分法在高羊茅品种综合评价中的应用

1999--2001年对引进和培育的高羊茅新品种(系)在喀斯特生态区进行品种比较试验。观测记裁各参试品种的性状表现，对春、夏、秋、冬4个季节的观测结果，用模糊评分法Ⅲ进行分析比较，并按综合评价值的大小排序a结果高羊茅“98--1”的综合评价值最大，排第一名，依次是猎狗5号、矮星2号、凌志(对照)，其余参试品种排名次后。认为用模糊评分法对高羊茅品种进行分析评价是可行的。     

提高阅卷与试题分析速度的有效方法探讨

分析了核对、打孔、光照透明、光电机器阅读和扫描等几种快速手工和自动阅卷评分方法。采用我校目前广泛使用的“成绩记载”中的浮动“阅卷面板”鼠标点击，以及自动阅读机与“成绩记载”间的“数据转换”程序，可大大提高成绩录入、成绩分析和试题分析速度。     

高产抗病柱花草新品种选育 II高产抗病柱花草品种比较

于 1998 - 2 0 0 0年选择 12个柱花草Stylosanthesguianensis新种质进行品种比较 ,结果表明 :Mineirao柱花草、GC15 81柱花草年干草产量分别为 116 5 0 0kg/hm2 和 114 2 0 0kg/hm2 ,高于热研 5号柱花草 (9831 1kg/hm2 ) 18 5 0 %和 16 16 % ;抗旱性强 ,在冬春低温干旱季节的干质量占年产量的 2 9 2 5 %和 2 9 15 % ;较抗柱花草炭疽病 ,试验期内平均病级分别为 1 6 7,1 74 ;植株越冬存活率分别为 30 83%和 4 1 6 8% ,耐寒性强 ;茎叶比为 1 0 3和 1 0 7,营养价值丰富 ,营养生长期粗蛋白含量分别为 15 36 2 %和 11 5 5 0 % ,是优良的柱花草新品种。     

区域证券市场发展潜力评价模型的建立及实证分析

建立了评价区域证券市场发展潜力的数学模型－定权聚类评估模型，并对河南各地区证券发展潜力进行了实证研究。     

评价适合选育加工型马铃薯品种的杂交组合

中国马铃薯的种植面积和产量均占世界首位,随着人们生活水平的提高和饮食结构的改善,以及外资企业在中国的纷纷建厂,对食品加工型马铃薯品种的市场需求日益增加,食品加工型马铃薯品种的培育已成为当务之急。本文根据食品加工型马铃薯品种的6项选育指标(炸制品质、薯形、产量、大中薯率、抗病性、熟期),对14个马铃薯杂交组合进行单个指标的评价和组合的级别评价,最终确定组合F81109×B5141-6、B5141-6×F58050、F67128×F61101、F49013×F61101、F71002×F59103可作为选育食品加工型马铃薯品种比较有前景的杂交组合。