Are hedgerows effective corridors between fragments of woodland habitat? An evidence-based approach

Anthropogenic modification of the countryside has resulted in much of the landscape consisting of fragments of once continuous habitat. Increasing habitat connectivity at the landscape-scale has a vital role to play in the conservation of species restricted to such remnant patches, especially as species may attempt to track zones of habitat that satisfy their niche requirements as the climate changes. Conservation policies and management strategies frequently advocate corridor creation as one approach to restore connectivity and to facilitate species movements through the landscape. Here we examine the utility of hedgerows as corridors between woodland habitat patches using rigorous systematic review methodology. Systematic searching yielded 26 studies which satisfied the review inclusion criteria. The empirical evidence currently available is insufficient to evaluate the effectiveness of hedgerow corridors as a conservation tool to promote the population viability of woodland fauna. However, the studies did provide anecdotal evidence of positive local population effects and indicated that some species use hedgerows as movement conduits. More replicated and controlled field investigations or long-term monitoring are required in order to allow practitioners and policy makers to make better informed decisions about hedgerow corridor creation and preservation. The benefits of such corridors in regard to increasing habitat connectivity remain equivocal, and the role of corridors in mitigating the effects of climate change at the landscape-scale is even less well understood.     

基于烧失量指数评估滨海沉积物中有机质特征

Understanding organic matter characteristics(e.g., amount and state) of sediments is necessary for evaluating both the sediment and water environments; however, methods that have been proposed to investigate these characteristics are relatively expensive. This study attempted to evaluate the organic matter characteristics of littoral sediments by employing solely the loss on ignition(LOI)method, which is the most economical and accessible method in developing countries. Different types of sediments were first oven dried at 100℃ and then continuously burned at 200, 300, 400, 500, and 600℃ for 4 h at each temperature. The mass LOI at each temperature was calculated and compared with the 100℃ oven-dried weight. Our results suggested that the mass LOI across the temperature range of 200–300℃(LOI_(200-300)):mass LOI at 600℃(LOI_(600)) ratio(LOI_(200-300)/LOI_(600)) could represent different types of sediments as well as the organic matter:organic C ratio. Compared with the sediments unaffected by wastewater, the sediments that were more influenced by the inflow of domestic wastewater had a higher LOI_(200-300)/LOI_(600). Interestingly, LOI_(200-300)/LOI_(600) could also represent changes in the organic matter characteristics as a function of organic matter decomposition in sediments. In conclusion, the organic matter characteristics of littoral sediments could be evaluated using solely the LOI method, particularly with LOI_(200-300)/LOI_(600).     

猪粪干、湿法厌氧发酵过程中碳、氮的流失

试验以新鲜猪粪为发酵原料,研究湿法和干法两种不同厌氧发酵过程的碳、氮排放量。湿发酵和干发酵组发酵料液的总固体(TS)含量分别为8%和20%,发酵液pH为6.8~7.4,发酵温度为35℃,体积为1.2 L,周期为21 d。试验期间每天测产气量,每4天取发酵样,测其全氮含量和TS降解率。结果表明,湿法和干法发酵组的CH4总产气量分别为9114 mL和12537 mL;CO2的总产气量分别为251.90 mmol和343.67 mmol;TS降解率分别为52.5%和29%。湿发酵的碳流失率和全氮流失率极显著高于干发酵(P<0.05)。     

日粮中添加不同水平的维生素E对小白牛肉贮存期间滴水损失率和TBA值的影响

本试验考察了饲料中添加维生素E(VE)对小白牛肉(中国荷斯坦公犊牛)贮存期间滴水损失率和TBA值的影响。试验选取16头小白牛,按体重随机分为4组,每组4头。在屠宰前30d每天添加不同水平的VE,添加水平分别为0mg/d、500mg/d、800mg/d和2 000mg/d。屠宰后将牛肉贮存14d。贮存期间选取滴水损失率和TBA值作为肉品质的考察依据。结果表明:随着贮存时间的延长,各组牛肉滴水损失率增加,而不同添加水平间差异不显著(P>0.05)。TBA值随时间延长而升高,从第4天开始,VE0组和VE500组,与VE800组和VE2000组之间差异显著(P>0.05),VE0组与VE500组,VE800与VE2000组之间差异均不显著(P>0.05)。表明饲料中添加VE800mg/d可使小白牛肉有很好的抗氧化效果。     

The effect ofDendrolimus superans breakout on growth of trees

The effect ofDendrolimus superans on growth of trees was investigated after the breakout in Shibazhan forest area in 1990. Stem analysis was conducted for determining the tree increment loss. The result showed that the current annual increment for extreme heavily damaged, heavily damaged, moderately damaged and lightly damaged stands is 14%, 39.8%, 64% and 82% of that of the control forest respectively. (Responsible Editor: Chai Ruihai)     

分叉角与回转半径对双向流道灌水器水力性能影响模拟研究

为研究双向流道灌水器水力性能，将其结构单元作为研究对象，以分叉角和回转半径两个结构参数为影响因素，采用正交试验设计16种结构参数组合方案，利用计算流体动力学软件Ansysfluent对流道内部流体的流动状态进行数值模拟，通过量纲分析建立流道结构参数与流道单元局部水头损失的回归模型。结果表明：双向流道单元局部水头损失与分叉角、回转半径和流道流速有关，分叉角与局部水头损失呈负相关关系，回转半径和速度与局部水头损失呈正相关关系；当入口流速为固定值时，分叉角为32.4°、回转半径为1.72 mm，流道单元局部水头损失最大；当设置10个流道单元时，交叉排列方式组合的灌水器流态指数较优。     

Thermoregulatory capacity of the Thoroughbred racehorse and its relationship to the pathogenesis of exertional heat illness

When racehorses fail to thermoregulate effectively, whether due to intrinsic or extrinsic factors, a condition called exertional heat illness (EHI) may occur, which can be life-threatening and represents a significant welfare issue. Horses usually become affected in the recovery phase soon after racing, so that a knowledge of the ‘normal’ thermoregulatory processes which operate at this time and their variations is essential to enable early detection of EHI. Racing in hot or warm and humid weather conditions represents the upper extreme of thermoregulatory variations, and observations on how horses normally recover at the racetrack may provide a clearer perspective on the physiology of that process for all sports horses. This review focuses on the post-exercise thermoregulatory capacity of the Thoroughbred racehorse, with a view to understanding the physiological mechanisms that should efficiently dissipate excess heat. The clinical manifestations of exertional heat illness are due to inadequate or harmful physiological responses, and if recognised and treated early can be effectively curtailed.     

气流干燥管计算中的几个问题

气流干燥装置已广泛地应用于鱼类饲料生产的烘干过程,气流干燥管是该类干燥装置中的主要干燥部件。干燥管的设计计算目前尚无一定的方法,不同学者各有已见。国内应用较多的有费道洛夫()法、桐荣良三法,南京化工学院和天津大学也有各自的计算方法。作者自1985年以来先后主持设计或改进设计了路程可调式通用有机物料气流干燥装置、0.5t/h和1t/h复合氨基酸饲料气流干燥装置等多套该类装置,根据设计计算过程中的经验和认识,对干燥管计算中的若干问题进行     

露天石矿开采工程水土保持研究

结合露天石矿开采建设的实例,对露天石矿开采项目建设会产生的水土流失进行预测及危害分析,并确定了总体防治目标及防治措施布设,分析了水土流失监测重点及水土保持措施功能,总结了露天石矿开采建设项目水土保持工作中的重点。