Idioms about animals

英语中表动物名称的名词大多数都有其习语用法,现珠海拾贝,让大家体验其丰富的词汇意义和文化内涵。     

丹尼斯女士主题单元教学法的实施

本文详细介绍美国优秀幼儿教师丹尼斯女士主题单元教学法具体实施过程，分析其教学特点，并对我国课程改革提出一些思考与建议。     

献县单桥栏板动植物装饰图案的民间艺术精神

从献县单桥的建造、栏板中动植物图案的选择及特点,说明单桥作为民间艺术,表现出宽和、仁爱、正直、坚韧、淳朴的精神,堪称优秀民间艺术的代表。     

Why search committees must be wary of ex-cavalry officers,Condorcet's paradox,and dictators

Given the current emphasis placed on affirmative action, it should come as a shock to many participants on selection committees to find that the most used balloting rule employed to determine the will of the committee is seriously flawed. The procedure, whereby candidates are assigned points based upon each voter's ranking, can frequently lead to a winner who is not the choice of the majority—a violation of the most central democratic concept. More surprising is the fact that the unsuitability of such weighted balloting has been known for over 200 years and that a Nobel Prize was awarded as recently as 1972 for research closely related to this problem. This paper traces the history of the research for a perfect, logical, democratic balloting rule, taking the reader through the paradox discovered by the Marquis Condorcet and Arrow's dictator theorem. A detailed exposition of approval voting explains why this new approach is gaining in popularity as perhaps the most reasonable replacement for the various voting rules now in effect.     

由一次区高中化学教师基本功竞赛触发的隐忧

从区高中化学教师基本功竞赛出现的问题,进行反思,并提出必须重视年轻化学教师的专业素质.     

人造纳米材料的环境风险

随着纳米技术的发展和纳米材料的人量开发生产及使用,纳米颗粒排放到环境可能产生的健康和环境风险开始引起广泛的关注,已经成为当前环境领域研究的热点。纳米颗粒的风险不仅来自它们的生物毒性,也与它们在环境中的浓度、形态、迁移转化过程及环境的复杂条件密切相关。自从发现纳米颗粒的生物毒性至今已十年,大量的相关研究工作已经促进了对纳米颗粒风险的了解,但距离全面掌控和准确评价它们的风险尚存在很大的距离。研究瓶颈如缺乏有效的研究技术手段、研究结果的不确定性、研究结果自相矛盾等普遍存在,是当前研究的挑战。本专辑收集了在该研究领域具有影响力的研究人员的最新研究成果和思考,介绍该领域的最新研究进展,希望能帮助读者了解相关研究工作并促进研究人员开展讨论,进一步推进该研究领域和纳米技术的持续发展。     

动物变态发育知多少

大自然中,动物个体发育的方式多种多样。许多动物的受精卵不直接发育为成体,而是先发育为有独立生活能力的幼体,再由幼体发育为成体。如果成体与幼体的形态结构、生活习性差别很大,这种个体发育方式称为变态发育（也叫间接发育）。相反,成体与幼体形态结构、生活习性没有差别,则叫做直接发育。动物变态发育种类繁多,最熟知的是昆虫和蛙的变态发育,简述如下。     

珍稀的透明动物及其人工培育和应用

本文介绍了几种珍稀的透明动物以及人工培育透明动物的研究进展和应用前景。     

基于当地材料制备高延性水泥基复合材料的研究(英文)

为了降低高性能聚乙烯醇(polyvinyl alcohol,PVA)纤维增强水泥基复合材料ECC(engineered cemen-titious composites)的成本,用国产PVA纤维和其他本地原材料如粉煤灰、水泥和细砂等研制了高延性ECC材料.采用四点弯曲试验和光学显微镜研究了ECC的弯曲变形能力、裂缝宽度及裂缝自愈合现象,并对其进行了经济性分析.实验结果表明:利用国产原料制备的ECC均表现出大变形能力,平均裂缝宽度能控制在60μm左右;开裂的试件经过干湿循环养护之后,裂缝中出现了自愈合现象;经济性分析表明利用国产PVA纤维可以极大地降低ECC成本.利用国产PVA纤维等材料制备高性价比的ECC是可行的.     

动物体内的酶与激素

酶与激素是生物体内活细胞所产生的2类重要的生物活性物质。酶是新陈代谢中的各种生化反应不可缺少的生物催化剂,激素则是调节新陈代谢等生命活动的重要微量有机物。本文从不同的角度对动物体内的酶和激素进行了比较,以阐明两者的关系。     

Identifying teaching in wild animals

After a long period of neglect, the study of teaching in nonhuman animals is beginning to take a more prominent role in research on social learning. Unlike other forms of social learning, teaching requires knowledgeable individuals to play an active role in facilitating learning by the naive. Casting aside anthropocentric requirements for cognitive mechanisms assumed to underpin teaching in our own species, researchers are now beginning to discover evidence for teaching across a wide range of taxa. Nevertheless, unequivocal evidence for teaching remains scarce, with convincing experimental data limited to meerkats, pied babblers, and tandem-running ants. In this review, our aim is to stimulate further research in different species and contexts by providing conceptual and methodological guidelines for identifying teaching, with a focus on natural populations. We begin by highlighting the fact that teaching is a form of cooperative behavior that functions to promote learning in others and show that consideration of these key characteristics is critical in helping to identify suitable targets for future research. We then go on to discuss potential observational, experimental, and statistical techniques that may assist researchers in providing evidence that the criteria that make up the accepted operational definition of teaching have been met. Supplemental materials for this article may be downloaded from http://lb.psychonomic-journals.org/content/supplemental.