科创中国

Satellite-tracking technology has allowed scientists to make a quantum leap in the field of migration ecology. Nowadays, the basic description of migratory routes of many species of birds has been reported. However, the investigation of bird migration at individual level (i.e. repeatability in migratory routes and timing) still remains seldom explored. Here, we investigated repeated migratory trips of a trans-Saharan endangered migratory raptor, the Egyptian Vulture Neophron percnopterus, tracked by GPS satellite telemetry. We compared between- and within-individual variation in migratory routes and timing in order to assess the degree of repeatability (or conversely, the flexibility) in migration. To this end, we analysed a dataset of 48 trips (23 springs and 25 autumns) recorded for six adult birds during 2007-2013. Our results showed consistent migration timing at the individual level, both in spring and autumn. Interestingly, there was a high degree of flexibility in the routes followed by the same individual in different years, probably due to variations in meteorological conditions. Contrary to expectations of a faster migration in spring than in autumn owing to a time-minimization strategy for breeding, birds spent less time in autumn migration (13 ± 2 days, range = 9-18 d) than in spring migration (19 ± 3 days, range = 13-26 d), which can be explained by differences in environmental con- ditions en route. Egyptian vultures showed a consistent clockwise loop migration through western Africa, following more easterly routes in autumn than in spring. Finally, our results provide supporting evidence of low phenotypic plasticity in timing of migration (i.e. strong endogenous control of migration) and high flexibility in routes [Current Zoology 60 (5): 642-652, 2014].

英语和法语同属于印欧语系,在语音、词汇和句法和时态上有很多相似之处.英语对法语的学习同时具有正迁移和负迁移.是回避还是直面语言迁移?其实,回避是回避不了的.直面迁移,明晰英语和法语的相似点和相异点,有助于强化其正迁移和克服负迁移.因此,英法互译可以成为法语教学的重要手段.

汽车行驶速度是公路设计指标的重要依据,更是道路交通安全的重要因素.然而.近年来随着我国高速公路通车里程的增加,公路设计人员的实践经验逐渐年积累,意识到现行路线设计规范采用的计算行车速度方法已不能真实反映我国交通的实际运行特性,无法保证线形标准的协调一致性,存在一定的安全隐患.为进一步保障和提高我国公路的行车安全,交通部颁发了《公路项目安全性评价指南》,初步提出了对我国公路安全性评价的内容、方法和标准,从行车安全性的角度要求高速公路和一级公路需进行公路安全性评价,以达到减少交通事故,降低交通事故危害的目的.本文正是基于这一条件,针对公路线形连续是保证汽车安全行驶的基本要素,结合某高速公路初步设计阶段,应用《公路项目安全性评价指南》中的运行速度协调性与设计速度与运行速度协调性,分析计算高速公路初步设计阶段的平、纵面线形设计的运行速度,对其整体线形的一致性进行分析评价.以求为下一阶段平、纵面指标的优化调整提供参考意见.

综述了纳米复合食品包装材料中纳米成分检测与迁移的国内外研究进展,重点就纳米复合包装材料中纳米成分检测的前处理方法、形貌检测和含量检测方法以及迁移研究进展进行了总结,为进一步的理论和实验研究提供参考.

By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants' flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while mi- grating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated [Current Zoology 60 (5): 660-669, 2014].

高达数十倍疯狂暴利,蒙蔽了商人的良心,欧美等发达国家的"洋垃圾"经中转走私进入大陆,涉及欧美、中转地和大陆三地的黑色链条就这样被搭建起来.近日,一起经"荷兰-台湾-大陆"的"洋垃圾"跨境走私路线图浮出水面.

我们经常遇到这样的情况,学生在学习物理知识时轻松、愉快,学习兴趣浓厚,可在解决实际问题时,往往一筹莫展,束手无策.究其原因是,在教学中重知识轻能力、学不致用.这种反差现象使我意识到:学生仅仅是懂得了物理知识还不足够,还要培养学生应用知识解决实际问题的能力,特别是知识迁移的能力.学生在学习过程中通过举一反三、触类旁通,把学到的某些物理原理、物理知识应用到学习新的知识或解决问题的活动中去,这就实现了知识的迁移.

利用2010年第六次人口普查数据,对我国人口迁移的特征及其影响因素进行研究.首先分析了包括年龄、性别、受教育程度和职业分布等在内的迁移人群的社会经济特征,继而从迁移原因、迁移人口的城乡分布、迁移时间、迁移类型与属性的交叉分析等方面探讨了人口迁移的类型学特征.引入就业可达性概念,分析了人口迁移率的空间格局、就业可达性与人口迁移率的空间匹配关系以及人口迁移流的空间格局,发现通过就业可达性格局可以很好地解释人口迁移率的分布.最后,采取多元线性回归技术研究了人口迁移的影响因素,结果表明,迁入地城镇居民收入与迁移率呈正相关关系,而迁出地城镇收入、迁入地的科技文化水平、迁移距离和迁入地农村收入则与迁移率呈负相关关系.

类比是将一类事物的某些方面进行比较,常以某一事物的正确或谬误证明这一事物的正确或谬误.类比法属于平行式思维方式,因此经类比后的推理也叫平行式推理.类比法的作用是由此及彼,因而类比法的特点是:先比后推.迁移是一个多角度、多方位的动词,这里所讲的迁移是知识点的迁移,有时我们还讲学习的迁移,它是学习活动中的一种方法,即把已获得的知识、情感和态度对后

动脉粥样硬化是血管慢性增殖性炎症过程,也是对血管损伤的反应和修复过程.高迁移率蛋白l作为一种重要的晚期炎症介质,参与多种炎性疾病的发生发展.Toll样受体是最重要的先天免疫系统的模式识别受体识别微生物的病原相关分子模式.高迁移率蛋白1可能通过Toll样受体激活炎性反应,参与动脉粥样硬化的发生和发展.