Effects of landscape pattern on bird species distribution in the Mt. Lofty Ranges,South Australia

We assessed how well landscape metrics at 2, 5, and 10 km scales could explain the distribution of woodland bird species in the Mount Lofty Ranges, South Australia. We considered 31 species that have isolated or partially isolated populations in the region and used the Akaike Information Criterion to select a set of candidate logistic regression models. The 2 km distance was the most appropriate scale for a plurality of the species. While the total amount of area of native vegetation around a site was the most important determining factor, the effect of landscape configuration was also important for many species. Most species responded positively to area-independent fragmentation, but the responses to mean patch isolation and mean patch shape were more variable. Considering a set of candidate models for which there is reasonable support (Akaike weights > 0.10), 12 species responded negatively to landscapes with highly linear and isolated patches. No clear patterns emerged in terms of taxonomy or functional group as to how species respond to landscape configuration. Most of the species had models with relatively good discrimination (12 species had ROC values > 0.70), indicating that landscape pattern alone can explain their distributions reasonably well. For six species there were no models that had strong weight of evidence, based on the AIC and ROC criteria. This analysis shows the utility of the Akaike Information Criterion approach to model selection in landscape ecology. Our results indicate that landscape planners in the Mount Lofty Ranges must consider the spatial configuration of vegetation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of restricting silage feeding prepartum on time of calving,dystocia and stillbirth in Holstein-Friesian cows

A study was carried out to investigate the effect of restricting silage feeding on time of calving and calving performance in Holstein-Friesian cows. In the treatment group (n = 1,248 cows, 12 herds) silage feeding commenced in the evening (17:00 to 20:00 h), after a period of restricted access (2 to 10 h) while in the control group ad-libitum access to silage was provided over the 24 h period (n = 1,193 cows, 12 herds). Daytime and nighttime calvings were defined as calvings occurring between the hours of 06:30 and 00:29 and between 00:30 and 06:29, respectively. Restricting access to silage resulted in less calvings at night compared to cows with ad-libitum access to silage (18 vs 22%, P < 0.05). Cows with restricted access to silage had a higher percentage of difficult calvings (11 vs 7%, P < 0.001) and stillbirths (7 vs 5%, P < 0.05) compared to cows in the control group. The percentage of calvings at night was lower (13%) when access to silage was restricted for 10 h compared to 2, 4 or 6 h (22, 18, 25%, respectively) (P < 0.001). Calf sire breed, calf gender or cow parity did not influence time of calving. In conclusion, offering silage to pregnant Holstein-Friesian cows in the evening, after a period of restricted access, reduced the incidence of nighttime calvings, but increased the incidence of dystocia and stillbirth.     

Vitamin E and Selenium Supplementation Reduces Plasma Cortisol and Oxidative Stress in Dystocia-Affected Buffaloes

The aim of the study was to evaluate oxidative stress around parturition in normally calved and dystocia-affected buffaloes and the clinical efficacy of vitamin E and selenium (Se) in reducing the effects in buffaloes suffering from dystocia. Plasma cortisol concentration, erythrocytic malondialdehyde (MDA) level and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were evaluated in dystocia-affected (supplemented (n = 8) and unsupplemented (n = 5) with vitamin E and Se) and normally calved (unsupplemented; n = 6) buffaloes. The decline in plasma cortisol concentration, MDA level and SOD activity was greater in the group of dystocia-affected buffaloes supplemented with vitamin E and Se (78.62 ± 2.7%, 13.38 ± 9.75% and 28.83 ± 7.72%, respectively) than in the unsupplemented group (54.33 ± 12.62%, 3.48 ± 4.16% and 17.69 ± 12.93%, respectively). These results suggests that supplementation with antioxidants like vitamin E and Se may be beneficial in reducing oxidative stress in dystocia-affected buffaloes in the immediate postpartum period.     

旋转折射式喷头动能分布规律试验

以圆形及平移式喷灌机常用的Nelson R3000型旋转折射式喷头(绿色喷盘,4流道)为研究对象,应用2DVD测试100、150和200 k Pa工作压力下的水滴粒径和速度,计算并分析了水滴直径与单个水滴动能之间的关系,单位体积水滴动能和动能强度沿射程的变化趋势。结果表明:单个水滴动能与水滴直径的3.65次方呈正比关系,随着至喷头距离的增加,测点单个水滴动能最大值、最小值及平均值增大;距喷头相同测点处,测点单个水滴动能最大值和平均值随着压力的增加而减小;单位体积水滴动能随着至喷头距离的增加呈指数关系增大;距喷头相同测点处,单位体积水滴动能随工作压力的增大而减小,并随着至喷头距离的增大差异增大;距喷头0~6 m范围内,3个工作压力下动能强度均小于0.02 W/m2,且差异较小;6 m至喷洒范围末端,3个工作压力下动能强度出现最大值,分别为0.117 2、0.082 7和0.052 2 W/m2,在距喷头距离相同测点处,动能强度随工作压力升高而减小。     

乌龙茶机的特性与使用方法

国内外对乌龙茶消费需求日趋加大,广西乌龙茶种植面积逐渐扩大,但乌龙茶加工在广西尚属起步,乌龙茶的加工机械不同于绿茶,本文介绍了几种常用乌龙茶机的性能及其使用方法,便于生产者选择机型并正确操作使用,以提高产品品质。     

应用型本科高校校内实践教学运行机制及绩效评价研究

高等院校人才培养目标与企业需求严重脱节,高校毕业生不能很好的适应企业岗位需求是现代高等教育面临的一个突出问题。校内实践教学是高校实践教学的重要环节,做好校内实践教学中教学形式课堂化、教学手段科学化、教学内容职业化、教学管理规范化的各项工作,是提高实践教学质量,实现专业培养目标的重要举措。该文以安徽科技学院为例,系统地研究了应用型本科高校校内实践教学运行机制及绩效评价方法,为现代高等教育应用型人才培养提供新思路、新方法。     

关于湛江地区土地整治工作的探讨

土地整治已日渐成为我国推进新农村建设和统筹城乡发展过程中解决土地利用问题的重要举措, 但目前大多数土地整治项目可能跨越农村地区,甚至镇和县,这将不可避免地涉及到多个村集体和农民等。因此,各部门之间必须有统一的领导和运行机制,但现行土地管制制度条件下不能完全保证达到较好的效果。本文阐述了湛江地区土地整治的机制,分析了湛江地区土地整治存在的问题,并提出在项目实操过程的操作模式及创新实践。     

奇台中心团场森林资源现状与经营策略

新疆生产建设兵团农六师奇台中心团场地处准噶尔盆地东南缘,该区森林资源在树种与林龄结构上不尽合理,而且森林质量较低。针对这种情况,提出了该区加强森林保护、积极培育森林、合理经营利用的策略。     

中国农业博物馆管理体制与运行机制研究

本文通过时国内外博物馆管理体制和运行机制的宏观考察,分析中国农业博物馆管理体制和运行机制现状及未来发展趋势,希望找到符合中国农业博物馆运作规律的管理体制和运行机制,促进博物馆事业的发展。     

乡村工业发展支撑体系及其运行机制

应用系统分析方法,探讨乡村工业发展支撑体系及其运行机制。系统描述乡村工业发展的硬投入、支持系统和软环境调控系统,以及系统发展的经济、动力和调控机制。