钢质渔船的腐蚀研究

本文根据对实船测厚数据的统计分析,阐述了钢质渔船船体外板的腐蚀特点,分析了造成腐蚀的原因,并对渔船易腐部位的防护提出了建议。     

乌骨鸡蛋形指数对孵化率的影响研究

将乌骨鸡种蛋按蛋形指数分为Ａ（≤７２．０％）、Ｂ（７２．１％－７４．０％）、Ｃ（７４．１％－７６．０％）、Ｄ（７６．１％－７８．０％）、Ｅ（≥７８．１％）五组进行孵化,结果表明：五组包骨 受精蛋孵化率分别为８２．６％、８６．１％、９０．２％、８７．２％、８２．５％、Ｃ组显著高于Ａ、Ｂ、Ｄ、Ｅ各组（Ｐ〈０．０５）,并极显著地高于Ａ组和Ｅ组（Ｐ〈０．０１）,蛋形指数为７４．１％－７６．０％的乌骨鸡种蛋孵化效果最佳。     

内蒙古典型草原草畜系统适宜放牧率的研究Ⅰ.以绵羊增重及经济效益为管理目标

(1)绵羊个体增重与放牧率呈线性负相关,个体最大增重临界放牧率,因季节不同而变化,随着个体增重与放牧率回归系数b绝对值的增大而降低,以始、终放牧期间所得临界放牧率最小,(2.04羊/hm²)。(2)公顷增重与放牧率的关系符合二次曲线,在达到公顷最大增重以前,随着放牧率的增大而增大,之后则随着放牧率的增大而下降,平均543羊/hm²。(3)公顷最大增重并不一定获取公顷最大利润,主要视买卖价格及其差值而定。(4)以冷蒿小禾草为主的退化草原,宜以个体最大增重的适宜放牧率作为管理标准,以使该类草原在利用中得以恢复。     

品种及初生重对仔猪死亡率和21日龄个体重的影响

试验对2 319头仔猪的初生重与21日龄个体重和死亡率进行分析。结果表明:大约克仔猪哺乳期死亡率最低,21日龄体重最高;随着初生重的增加,仔猪死亡率降低,21日龄个体重增加。     

Can supplemental food increase winter survival of a threatened cottontail rabbit?

Populations of New England cottontails (Sylvilagus transitionalis) have declined substantially in recent decades in response to habitat loss and fragmentation. Among some remnant populations, cottontails occupy small patches of thicket habitat where they experience high mortality rates as a consequence of limited food during winter. This limitation causes rabbits to forage away from cover where they are exposed to predators. Although conservation efforts are emerging to reverse the decline of New England cottontails, most are directed toward improving long-term viability by increasing the abundance of suitable habitats. Such efforts do little to improve the short-term survival of remaining cottontails. To address this immediate need, we evaluated the use of supplemental food as an approach to improve overwinter survival rates. We speculated that by positioning feeders in close proximity to escape cover, rabbits would be less vulnerable to predators. We evaluated this approach using eastern cottontails (Sylvilagus floridanus) as a research surrogate because this species is readily available and has similar habitat requirements to New England cottontails. Transmitter-equipped eastern cottontails were randomly assigned to either a fed or unfed group. Remotely-triggered cameras were also used to gauge use of feeders by cottontails and visits by other species. Winter survival rates were substantially greater for fed rabbits (70%) than for unfed rabbits (32%). Cameras revealed that rabbits were the most frequent consumer and that there was only limited carnivore activity near feeders. We conclude that supplemental feeding may improve survival of remaining New England cottontails as efforts to increase habitat availability continue to develop.     

植保无人飞机对4种棉花喷施脱叶催熟剂的效果研究

目的 研究棉花收获前植保无人飞机喷施脱叶催熟剂的效果。方法 使用植保无人飞机以22.5 L·hm^-2的施药液量喷施采收前30 d的棉花‘金棉18#’、‘北泉9#’、‘植金13#’和‘合信47#’,以人工机械喷雾(施药液量450 L·hm^-2)为对照,测试4种棉花冠层中的雾滴覆盖率;于药后4、7、14和21 d分别进行脱叶和吐絮效果调查,计算不同棉花品种的脱叶率和吐絮率;检测4种棉花的纤维品质和产量构成因子(铃质量、衣分)。结果 雾滴覆盖率在4种棉花品种中均呈现出上部冠层显著高于中下部冠层的规律,且植株越高,中下部冠层的雾滴覆盖率越低;除‘合信47#’人工喷雾处理的吐絮率没有达到机采棉采收标准外,其余处理的脱叶率和吐絮率均达到了机采棉的采收标准;4种棉花品种的纤维品质和产量构成因子(铃质量、衣分)均不受施药器械的影响。结论 植保无人飞机可作为棉花采收前喷施脱叶催熟剂的施药器械。     

不同来源绿僵菌对油桐鹰尺蠖幼虫的致病力比较

油桐鹰尺蠖Biston suppressaria (Guenée) 是一种杂食性食叶害虫,近年来在速生桉树林分中大 面积发生,造成较大的损失。文中研究了不同来源金龟子绿僵菌Metarhizium anisopliae 菌株生长与产孢 特性及对油桐鹰尺蠖幼虫的致病力,旨在筛选出高效防治该虫的生物资源。试验结果表明：不同来源的 绿僵菌菌株间菌落生长速度和产孢量差异显著,MaZPTR-01 菌株15 d 的菌落直径为6.5 cm,显著较其它 菌株大;MaFZ-13 和MaZPTR-01 菌株培养15 d 产孢量最高,分别为1.33×108 孢子· cm-2 和1.28×108 孢 子· cm-2。致病力测定结果表明：不同菌株对油桐鹰尺蠖幼虫的致病力存在显著差异,其中接种MaFZ-13 和MaZPTR-01 菌株的幼虫校正死亡率、僵虫率均较其它菌株高,接种后15 d 幼虫校正死亡率分别达到 94.5%、92.7%,僵虫率分别为75%、61.7%;这2 个菌株的致死中时（LT50）显著比其它菌株短,分别为 4.34 和4.52 d。绿僵菌MaFZ-13 和MaZPTR-01 菌株对油桐鹰尺蠖幼虫的致病力强,且具有良好的生产性 状,可作为该虫的生物防治资源进一步开发应用。     

大豆油不同添加水平对瘤胃体外发酵和产气的影响

本试验通过体外培养,研究在精粗比为30:70(偏粗型)日粮类型条件下,不同大豆油添加水平对产气量、甲烷产量、pH值和纤维降解率的影响.结果表明:随着大豆油添加水平的提高,产气量和甲烷产量逐渐降低,且各添加组显著低于对照组;pH值随着培养时间的延长,各添加水平在不同培养时间点与对照组相比均上升,其中添加量为4%和6%与对照组相比差异显著(P<0.05),添加量为8%时,与对照组相比差异极显著(P<0.01);培养24 h后.纤维降解率的抑制潜力8%水平最大,与对照组相比差异极显著(P<0.01),其次是6%的添加水平.与对照组相比差异显著(P<0.05).而2%和4%添加水平对纤维降解率的抑制程度与对照组相比差异不显著(P>0.05).通过产气量、pH值和纤维降解率综合考察大豆油对瘤胃体外发酵和产气的影响,本试验得出大豆油的最适添加量为4%.     

提高烤烟C4F收购等级合格率的途径

烤烟C4F是中部烟叶相对其他等级价廉物美的一个等级,其配伍性强,工业企业需求量大。近年来,由于烟叶收购站点的收购人员、预检人员和烟农对C4F的标准把握不准确,造成C4F及其相邻等级收购等级合格率偏低。因此,通过研究提高C4F等级合格率的途径,对提高烟草等级的合格率具有重要的意义。     

Detection of cigarettes and other tobacco products by giant African pouched rats (Cricetomys gambianus)

If the illicit tobacco trade were eliminated, governments could gain at least $31.3 billion a year, and more than 164,000 premature deaths a year could be avoided after 2030 (Joossens, Merriman, Ross, and Raw, 2009). Dogs have been used successfully in tobacco control programs, and there is a good chance that rats could also play an important role. In the present experiment, giant African pouched rats were trained to respond to filters that had been stored together with cigarettes (i.e., soaked) and to not respond to filters that had been soaked with noncigarette items. Generalization to untrained types of tobacco was then tested. The sensitivity of 4 rats trained on filters soaked with 1 of 7 types of cigarettes ranged from 86% to 100% (mean, 95%). There was very little evidence of generalization when the rats were tested on tobacco leaves and snuff but good evidence of generalization when the rats were tested on cigarettes that had been soaked with strong-smelling additives. These findings suggest that rats may be a valuable asset in the global effort to control illicit cigarette trade.