叶尔羌高原鳅低温下耗氧率和窒息点的研究

试验采用流水呼吸室法和静水呼吸室法测定了叶尔羌高原鳅在低温6.5~7.5℃条件下的耗氧率和窒息点。结果表明,叶尔羌高原鳅耗氧率具有昼夜节律性,耗氧高峰在5:00左右,低谷在15:00左右,其耗氧率和窒息点随体重的增加而增加,随水温的升高而增大。叶尔羌高原鳅适应低温能力较强,适宜生长温度6~29℃,最佳生长温度8~15℃。     

Seasonal Changes in Quality and Fatty Acid Composition of Black Mussel (Mytilus galloprovincialis)

The study was designed to assess the seasonal variations in the quality and lipid profile of mussel meat (Mytilus galloprovincialis) harvested along the Bulgarian coast of the Black Sea. The trial period lasted from June to October, and the sampling was carried out in the area of Varna Bay. Technological quality of the mussels was determined by measuring the water holding capacity (WHC) and cooking and roasting losses. Proximate composition, total aerobic plate count, and fatty acid analysis were carried out. Technological parameters and nutritional quality of the mussel meat were strongly affected by the season. During the summer, the mussels had higher mass, meat content, and meat yield (p < 0.001) compared to the early autumn, which corresponds to the lowest protein content during this season. Lipid profile showed seasonal variations in both individual and total fatty acid amounts (p < 0.001). Saturated fatty acids (SFA) had the highest content in summer, while monounsaturated fatty acids (MUFA) decreased gradually until the autumn. The content of polyunsaturated fatty acids (PUFA) reached its peak in October, contributing to the most favorable values of the nutritional indices of lipids in the early autumn.     

长江中上游圆口铜鱼的种群死亡特征及其物种保护

根据葛洲坝(1998～2007年)、重庆(2006～2007年)和合江江段(1998～2005年)的渔业资源调查资料,对圆口铜鱼的种群死亡特征进行了评估,并利用Beverton-Holt模型的单位补充量渔获量方程,分析和探讨了长江中上游圆口铜鱼资源的合理利用.结果表明:1)3个江段各年间的圆口铜鱼开发率和捕捞死亡系数均远远大于相应年份最大允许的开发率和捕捞标准的基准尺度F0.1,3个江段的圆口铜鱼资源均处于严重过度捕捞状况;2)葛洲坝江段圆口铜鱼的最适开捕年龄为4龄(体长330mm),重庆和合江江段圆口铜鱼的开捕年龄应至少为5龄(体长375 mm).为保护圆口铜鱼的资源,建议葛洲坝江段三层流刺网的网日(2a)应大于75 mm为宜,重庆和合江江段的网目(2a)应不小于90 mm且同时需要控制各种渔具的日均作业次数.     

转基因与野生唐鱼耐温限度及窒息点的比较研究

对转红色荧光蛋白基因唐鱼、野生型唐鱼Ⅰ和野生型唐鱼Ⅱ的耐温和耐氧能力进行比较研究。结果表明,在驯化温度为30 °C,升温速率为1 °C / h时,三种唐鱼的半致死高温分别为：38.53±0.08 °C、38.28±0.29 °C和38.55±0.09 °C。在驯化温度为25 °C,降温速率为2 °C / 24h时,三种唐鱼的半致死低温分别为：1.13±0.40 °C、1.26±0.10 °C和1.21±0.12 °C。恒温25 °C时,测定三种唐鱼的窒息点分别为：0.66±0.02 mg/L、0.74±0.21 mg/L和0.51±0.01 mg/L。差异显著性检验表明,三种唐鱼对温度和溶氧的耐受力无显著性差异。     

真鲷窒息点与耗氧率的初步测定

真鲷(Pagrosomus major T and S)是广东及其他各省市沿海海水网箱养殖的主要鱼类之一。随着真鲷人工繁殖和苗种培育的成功,真鲷养殖业将会有一个更大的发展。夫于鱼类的窒息点与耗氧率的研究早有不少,但是对真鲷除个别学者提及其窒息点外,真正对其窒息点与耗氧率的系统研究尚未见到。为了绘其鲷的人工繁殖、苗种培育、运输和成鱼养殖提供呼吸生理方面的理论依据,笔者于1990年春对真鲷的窒息点和耗氧率进行了初步测定,就不同规格大小的苗种及备种外界条件与窒息点和耗氧率之间的关系进行了初步探讨。     

Phytochemical and antioxidant properties of anthocyanin-rich Morus nigra and Morus rubra fruits

In this study, phytochemical and antioxidant properties of anthocyanin-rich mulberry species of Morus nigra L. (black mulberry) and Morus rubra L. (red mulberry) fruits harvested from across Turkey were investigated. Fruit color, total phenolics (TP), total monomeric anthocyanin (TMA), titratable acidity (TA), and individual sugar and organic acid compositions were determined. Total antioxidant capacity (TAC) of fruits was assessed by both the trolox-equivalent antioxidant capacity (TEAC) and the ferric reducing antioxidant power (FRAP) assays. Black mulberry exhibited higher TP, TMA, TAC and TA when compared to red mulberry. The average TP contents of M. nigra and M. rubra were 2737 and 1603 μg gallic acid equivalent in g fresh weight basis (GAE/g fw), respectively. M. nigra had the richest amount of anthocyanin with an average of 571 μg cy-3-glu/g fw. Overall, TAC averaged 10.5 and 12.0 mmol TE/L by the TEAC and FRAP methods, respectively. We found that FRAP, TEAC, TP and TMA were significantly correlated (r = 0.64–0.99) with each other. Fructose (5.27 g/100 mL) and glucose (5.81 g/100 mL) were determined to be the major sugars in both mulberries. M. nigra displayed a higher TA (2.05 g/100 mL) than M. rubra (0.78 g/100 mL), with citric acid as the major acid.     

黄连、黄芩提取液与二氧化氯复配对结球甘蓝种传黑斑病的抑菌效果研究

采用三元二次回归正交旋转组合设计方法,确立了黄连、黄芩提取液与二氧化氯对甘蓝链格孢菌抑制效果最佳的复配组合:黄连提取液13.48%、黄芩提取液15.56%、二氧化氯0.14%.用此复配剂浸种,芸苔链格孢菌和甘蓝链格孢菌的侵染率分别降低了97.33%和94.85%,且提高了种子发芽势及萌发相关酶活性.     

The significance of meandering channel morphology on the diversity and abundance of macroinvertebrates in a lowland river in Japan

• 1. Many rivers and streams across the world have been channelized for various purposes. Channel cross‐sections of meandering rivers are asymmetrical and have cross‐sectional diversity in their physical environment; cross‐sections of a channelized river are typically trapezoidal and have little cross‐sectional diversity, both in physical and ecological conditions. Several programmes to restore stream meanders have been undertaken to improve river ecosystems degraded by channelization. However, the association between diversification in the physical environment due to meander restoration and the macroinvertebrate community structure is poorly known.
• 2. This study of a lowland river in Japan assessed how the cross‐sectional diversity of the physical environment changed with restoration of a meander in a channelized river, and how the macroinvertebrate communities responded to the changes in physical habitat variation. Comparisons were made between the macroinvertebrate communities of a channelized reach, the restored meandering reach, and a natural meandering reach.
• 3. Natural meandering and restored meandering reaches showed higher cross‐sectional diversity in physical variables and total taxon richness across a reach than did the channelized reach. Almost all taxa observed in the natural and restored meandering reaches were concentrated in the shallowest marginal habitats near the banks. Shear velocity increasing with water depth had a negative association with macroinvertebrate density and richness.
• 4. This study demonstrated that the shallow river bed along the inside of bends formed point bars that provided a highly stable substrate, a suitable habitat for macroinvertebrates in a lowland river. It is concluded that meander restoration could be an effective strategy for in‐stream habitat restoration in lowland meandering rivers.

Copyright © 2007 John Wiley & Sons, Ltd.     

Nitrate leaching in a silage maize field under different irrigation and nitrogen fertilizer rates

Quantification of the interactive effects of nitrogen (N) and water on nitrate (NO₃) loss provides an important insight for more effective N and water management. The goal of this study was to evaluate the effect of different irrigation and nitrogen fertilizer levels on nitrate-nitrogen (NO₃-N) leaching in a silage maize field. The experiment included four irrigation levels (0.7, 0.85, 1.0, and 1.13 of soil moisture depletion, SMD) and three N fertilization levels (0, 142, and 189 kg N ha⁻¹), with three replications. Ceramic suction cups were used to extract soil solution at 30 and 60 cm soil depths for all 36 experimental plots. Soil NO₃-N content of 0-30 and 30-60-cm layers were evaluated at planting and harvest maturity. Total N uptake (NU) by the crop was also determined. Maximum NO₃-N leaching out of the 60-cm soil layer was 8.43 kg N ha⁻¹, for the 142 kg N ha⁻¹ and over irrigation (1.13 SMD) treatment. The minimum and maximum seasonal average NO₃ concentration at the 60 cm depth was 46 and 138 mg l⁻¹, respectively. Based on our findings, it is possible to control NO₃ leaching out of the root zone during the growing season with a proper combination of irrigation and fertilizer management.     

数字化人体模型在车身逆向布置中的应用

以人体参数为依据建立的数字化人体模型能有效的描述人体的形态特性.本文在CATIA人机工程模块中,建立了人群文件,生成自定义的三维数字化人体模型。在此基础上建立了满足不同百分位需求的参数化人体模型。以某汽车为对象,根据SAE标准,综合考虑了踏板行程、汽车视野和上下肢舒适性等因素对驾驶员的影响,最终得到满足各种约束的驾驶员最佳舒适性H点区域。论文研究为针对不同地区人群特性对车型进行逆向开发和逆向布置提供了很好的参考。