Spatiotemporal programs and genetics of orientation

Summary A number of migratory bird species have endogenous annual rhythms that regulate the entire annual cycle including the migratory portion. Moreover, captive migrants display inherited migratory activity; this could theoretically also be used by free-living migrants as a time-program for migration. Finally, this heritable migratory activity is oriented in a seasonally appropriate direction even in naive birds. These, characteristics should enable inexperienced migrants isolated from contact with experienced conspecifics to utilize a heritable vector-navigation program to migrate from the breeding grounds to the winter quarters. That is, migrants should reach goal areas they have never experienced by migrating in programmed directions, for as long a period as the genetically fixed time-program for migratory activity induces them to do so. The time-course of migration as established by trapping stations, theoretical influences of environmental variables on migratory programs, and also compensatory behavior and migratory backup measures, are discussed. The present evidence supports the view that a large number of migrants are essentially brought to their wintering areas by vector-navigation systems.     

Interpreting animal wall-following behavior

Summary Using computer simulations and behavioral experiments with the American cockroach, we found that active vs passive (barrier-directed) wall-following can be readily distinguished and quantified by incorporating a range of convex curves into test arenas. Although previously considered strongly thigmotactic, more than 50% of running American cockroaches depart convex curves with diameters, less than 1 m. A new framework for evaluating wall-following behaviors is presented.     

Wind and orientation of migrating birds: A review

Summary Migratory flights are strongly affected by wind, and birds have developed many adaptations to cope with wind effects. By day, overland migrants at high altitudes may often allow crosswinds to drift their tracks laterally from the preferred heading. In contrast, many birds at low altitude adjust their headings to compensate for drift, and may overcompensate to allow for previous drift. The relative motion of landscape features is probably used to sense drift, at least by day. By night, some overland migrants compensate fully for drift but others do not; no pattern is obvious. Over the sea, compensation is rarely if ever total; wave patterns may allow partial compensation. Other adaptations can include reduction of drift by flying at times and/or altitudes without strong crosswinds. Some birds recognize the need to change course to allow for previous wind displacement, and reorient at least roughly toward the original route or destination. Some juveniles en route to previously-unvisited wintering grounds seem to have this ability, but corroboration is needed. Such reorientation may not require a true navigation ability. However, some birds have unexplained abilities to sense the wind while aloft.     

浅议现代平面设计色彩观的价值取向

从现代与传统之间的关系来看,现代平面设计色彩观的价值取向应该是关怀大众的生活质量的提高,以让观众更快、更直接地获取设计中所要表达的主要信息为目的;现代平面设计是追求人文精神和社会责任感的设计。     

不幸爱情与尴尬亲情中的伦理道德取向——评《枉费心机》中的阿尔克利芙小姐

《枉费心机》围绕着女主人公塞西利亚与男主人公爱德华的爱情遭遇展示了小说中的主要人物在处理亲情、友情、爱情与婚姻关系中所表现出来的伦理道德取向。作为主要人物之一的阿尔克利芙小姐在处理爱情与亲情关系的过程中面临着伦理道德的考验。通过所作出的伦理道德选择，她获得了对自己、对塞西利亚、对曼斯顿以及对社会伦理道德更清醒的认识，从而在道德上进一步成熟。     

聚丙烯纤维水泥稳定碎石断裂能试验研究

为了研究聚丙烯纤维对水泥稳定碎石断裂韧性的影响，通过对84个尺寸为100 mm × 100 mm × 515 mm的聚丙烯纤维水泥稳定碎石和普通水泥稳定碎石三点弯曲试件断裂试验，测得了试件的断裂能(GF)、裂缝嘴张开位移(CMOD)和裂缝尖端张开位移(CTOD)，并探讨了试验龄期、聚丙烯纤维体积掺量以及水泥掺量对聚丙烯纤维水泥稳定碎石断裂能的影响，对聚丙烯纤维水泥稳定碎石的经济性和施工和易性进行了简要分析，给出了聚丙烯纤维体积掺量合适的建议范围为0.6‰ ～ 0.8‰。试验结果表明：聚丙烯纤维的掺入可以明显提高水泥稳定碎石的断裂能、极限裂缝嘴张开位移(CMODmax)和极限裂缝尖端张开位移(CTODmax)；随着试验龄期的增长，无论聚丙烯纤维掺入与否，水泥稳定碎石断裂能均呈增大趋势，但聚丙烯纤维水泥稳定碎石断裂能增大的速率较大；随着纤维体积掺量的增加，水泥稳定碎石断裂能、CMODmax和CTODmax逐渐增大，尤其是当纤维体积掺量大于0.6‰时，GF增大的效果更为明显；随水泥掺量的增加，聚丙烯纤维水泥稳定碎石试件的极限荷载逐渐增加，但断裂能却逐渐减小。     

有关北京学的几点思考

建立北京学是客观需要，分别研究北京的方方面面，都不称其为北京学，真正的北京学应当是在这些分别研究的基础上升华形成的能够揭示有关北京各方面更深层次奥秘的科学理论体系。加强北京学的基础理论研究，广泛深入地开展北京学的应用研究，重视对北京学的宣传工作和加强北京联合大学北京学研究所科研条件和科研队伍的建设，是今后北京学发展的主要方向和任务。     

论高校思想政治工作与人本回归

高校思想政治工作存在偏离人本的现象,忽视大学生的主体性、个性发展、自身需要和价值,必须回归到"以人为本"的教育理念上来,科学理解把握高校思政工作"以人为本"的内涵要求,以大学生的需要为出发点,以大学生的发展完善为目的,转变思想观念,将服务主体与教育主体有机统一起来,建立个性化培养制度,引导学生全面发展.     

高职教育的人才培养目标定位研究

要：高职院校培养的人才是否受到社会的欢迎，决定于诸多因素，而更重要的，则决定于学校对培养目标的界定是否准确、专业设置是否优化并反映时代特征。因此我们应当准确把握社会发展方向，以社会需要为依据，对人才进行合理定位，努力培养出社会真正需要的高等职业技术人才。     

波分复用和频分复用光纤通信技术研究

波分复用(WDM)和频分复用(FDM)技术可用来充分开发光纤的宽频带特性,实现超大容量信息传输。在“八五”期间科研成果基础上,完成了4×2.488Gbit/s双向154km无中继波分复用光纤通信系统,并已安装于京九九光缆干线广州-深圳段通信线路上作现场试验和试运行。该系统工作稳定可靠,在5个多月试运行中未发现误码。同时,完成4×155Mbit/s频分复用光纤通信实验系统的研制。该系统频道间距为0.1nm,传输距离为18km。系统实现了模块化结构,具有良好的稳定性,实测24小时无误码。这一成果为FDM的应用打下了基础。