Flour beetles: responses to extracts of their own pupae

Two species of flour beetles, Tribolium confusum and Tribolium castaneum, respond to neutral pith disks impregnated with aqueous extracts of their pupae in such a way that the adults and larvae tend to select the extract of the other species. These findings have implications for the population ecology of Tribolium.     

Propagation of a magnetic domain wall in a submicrometer magnetic wire

The motion of a magnetic domain wall in a submicrometer magnetic wire was detected by use of the giant magnetoresistance effect. Magnetization reversal in a submicrometer magnetic wire takes place by the propagation of a magnetic domain wall, which can be treated as a "particle." The propagation velocity of the magnetic domain wall was determined as a function of the applied magnetic field.     

引导大学生“村官”自主创业思考

选派高校毕业生到村任职,是党中央做出的一项具有长远战略意义的重要决策,实践亦证明,大学生"村官"在社会主义新农村建设中发挥了积极作用。本文通过对苏北地区部分市县大学生"村官"创业经验调查发现,大学生"村官"期满后就地创业大有可为。     

How organic farmers view their own practice: results from the Czech Republic

This paper addresses the development of organic agriculture in the Czech Republic, which is seen as a success story among post-communist countries. The relatively short history of organic farming and specific contextual factors raises questions about the nature and meaning of Czech organic farming. The goal of this study was to find out how farmers view their own practice, interpret its symbolic value, and construct its content. This empirical study uses Q methodology aimed at the identification of the collectively-shared perspectives belonging engaged actors. Data were gathered through semi-standardized interviews with Czech farmers registered in official organic scheme. The analysis emphasized three components, which are considered as three distinct perspectives possessed by organic farmers; that is, (1) organic farming as a way of life, (2) as an occupation, and (3) as a production of food of an alternative quality compared to conventional food. Each viewpoint entails a different understanding of what organic farming means; each then—when considered together—comprises the meaning of organic agriculture in the Czech Republic. The presented classification of the farmers holding the viewpoints contributes to the ongoing theoretical discussion regarding the nature of the current organic sector, its development and potential conventionalization.     

福建省农民工回乡创业的调查与思考

通过对福建省农民工回乡创业的实地调研和问卷调查,分析了福建省农民工回乡创业的现状与特点,以及农民工回乡创业给福建新农村建设带来的经济社会效应,指出了福建省农民工回乡创业过程中所面临的主要困难和问题,最后提出了进一步鼓励、引导和挟持农民工回乡创业的政策建议：（1）各级政府要统一思想认识,高度重视农民工回乡创业这一客观现象;（2）切实为农民工回乡创业提供优质服务,优化创业环境;（3）创新农村金融服务,解决农民工创业融资难题;（4）对回乡创业农民工进行创业指导和创业培训;（5）以县城为中心搞好小城镇发展规划,加强基础设施建设;（6）以情招商,采取多种形式把有创业意愿和创业能力的农民工“请回来”;（7）立足当前,着眼未来,采取多种渠道逐步解决人才问题;（8）大力宣传回乡农民工创业的先进事迹,不断激发创业热情。     

不同土地利用方式下的生物量季节动态研究

[目的]研究不同土地利用方式下的生物量季节动态。[方法]于2008年生长季（5～10月）期间,分别测量了针茅群落、羊草群落和农田3个不同地表覆盖状况下的植物地上生物量和地下生物量。[结果]地上生物量均在8月达到最高值,羊草、针茅和农田的地上生物量分别为287.91、117.05、193.59 g/m2;3个样地植物根系总生物量在7月最高,针茅、羊草和农田样地分别为1 683.9、1 601.9、513.9 g/m2;植物上层根系0～15 cm/植物下层根系15～30 cm的生物量比率最大的是羊草,针茅次之,农田最小。[结论]为生态脆弱地区的生态环境保护提供了理论依据。     

不同土地利用方式下的生物量季节动态研究(摘要)(英文)

[目的]研究不同土地利用方式下的生物量季节动态。[方法]于2008年生长季(5～10月)期间,分别测量了针茅群落、羊草群落和农田3个不同地表覆盖状况下的植物地上生物量和地下生物量。[结果]地上生物量均在8月份达到最高值,羊草、针茅和农田的地上生物量分别为287.91、117.05、193.59g/m2;3个样地植物根系总生物量在7月份最高,针茅、羊草和农田样地分别为1683.9、1601.9、513.9g/m2;植物上层根系0～15cm/植物下层根系15～30cm的生物量比率最大的是羊草,针茅次之,农田最小。[结论]该研究为生态脆弱地区的生态环境保护提供了理论依据。     

Technology of inertia threshing of pulses

A technology of harvesting pulses without damaging the grain is proposed. The threshing-separating machine allows reducing the main parameters of the combine and fuel consumption and broadening the moisture content range up to 30% during harvesting with 100% threshing of grain.     

不同控制条件下土壤中苄嘧磺隆的残留动态初探

采用高效液相色谱法测定了苄嘧磺隆在不同控制条件下土壤中的残留动态,结果表明：pH分别为5、7、9的土壤中,苄嘧磺隆的半衰期分别为13．0、17．9、59．7d;温度为15、25、35℃条件下,苄嘧磺隆的降解半衰期分别30．4、27．7、16．6d;在有机质含量为15、20、35g／kg的土壤中,苄嘧磺隆的降解半衰期分别为58．7、32．7、29．2d。土壤含水量从10％增加到40％和60％时土壤中的苄嘧磺隆降解的半衰期则从27．3d减少到17．9d和15．0d。     

农牧交错区不同耕作措施下莜麦的生长发育规律

为解决农牧交错带长期免耕下作物减产的问题,本研究通过定位试验,对覆盖和不覆盖条件下少免耕与翻耕莜麦的生长发育状况进行对比分析.结果表明1)在无覆盖的条件下,免耕处理出苗率指数大于翻耕处理,且2006 年深松处理出苗率指数(0.084 0)与翻耕处理(O.0705)差异达显著水平;2)免耕与深松无覆盖处理根冠比大于翻耕处理;3)免耕无覆盖处理生物量及产量均显著小于翻耕处理;深松无覆盖处理根系生物量显著大于翻耕处理,但地上部生物量与产量小于翻耕处理,且产量差异显著,2005、2006年分别降低了15.8%和10.0%;免耕与深松无覆盖处理千粒重均大于翻耕处理,但差异不显著,2005年分别为19.7、18.9和17.6 g;4)免耕覆盖处理生长明显改善,但生物量及最终产量仍显著低于翻耕处理,2006年产量与翻耕处理相比降幅达19.7%,免耕覆盖处理对于莜麦产量的影响大于免耕耕作措施本身对莜麦产量的影响;深松覆盖处理生长状况及产量与翻耕处理间均无显著差异.覆盖下的深松(行距50 cm,深度40 cm,隔年进行)是适合农牧交错带的少免耕模式.     

分子动力学模拟高温高压下水的粘度

由于高温高压的极端条件实验室很难实现,因此应用分子动力学方法模拟计算水在高温高压下的粘度成为一种重要的手段。模拟实验基于分子动力学方法,针对水分子的特殊结构,引入Ewald法求长程作用力和四元素法,采用等温等压条件,最终模拟得到不同温度、压强下水的粘度并与实验值进行比较分析。     

黄竹侵入对热带林地土壤养分的影响

通过对黄竹林的入侵、定居和扩散3个演替阶段土壤养分状况的分析，探讨了黄竹林的形成和发展对土壤养分的影响。结果表明：随着黄竹群落演替的进行，土壤有机质和全氮的质量分数逐渐减小。土壤全氮质量分数分布类似于有机质，并呈现正相关性（r＝0．8586，n1＝n2＝51）；随着群落演替的进行，黄竹林地表土层的全磷质量分数和有效性磷的质量分数逐渐增大，有效性磷素的缺乏是植物生长的限制因子之一；黄竹林地土壤钾的质量分数和有效性钾的质量分数以侵入期至定居期下降 的幅度最大，此后到扩散期又稍有回升；土壤有效性钙和镁的质量分数随着演替的进行而增加。     

Chemical Insect Attractants: Insects promote their own destruction in responding to traps baited with specific lures

Many insects depend on odors to lead them to sources that supply their basic needs. Knowledge of these behavioral patterns helps to combat insects of economic importance. For example, attractants in traps offer a remarkably simple means of detecting insects and may even be useful in direct control. They are increasing the efficiency of insecticide applications because treatments need be applied only where insects are caught and only as long as they are caught.