基于Blackboard平台协助学习活动设计策略研究

网络协助学习活动设计不仅仅关注表现和内容,更注重学习者的学习体验。本研究采用调查法、案例分析法相结合等研究方法,提出了网络协助学习活动设计4项策略,并通过Blackboard平台展开实证研究。研究结果表明：学生的在线学习动力与教师的指导方式呈正相关;以合作引导型为主、个别授导型为辅的方式,才能取得较好的协助学习效果。     

A structural and empirical model of subsistence activity behavior and income

This paper develops a structural and empirical model of subsistence activity behavior and income. Subsistence activity decisions (work participation and hours of work decisions) and income have an important bearing on activity and travel behavior of individuals. The proposed structural model represents an effort to analyze subsistence activity behavior and income earnings to support a better understanding, and reliable forecasting, of individual travel behavior. The empirical model formulates and estimates an integrated model of employment, hours of work and income which takes account of interdependencies among these choices and their structural relationships with other relevant variables. Social factors that inhibit an individual's employment and work hours decision and affect an individual's income are incorporated in the model. A sample of households from the Dutch National Mobility Panel is used in the empirical analysis.     

硫酸镁对哇巴因诱发豚鼠心脏自发电活动的生理效应

本文采用细胞内固定微电极技术观察了硫酸镁对哇巴因所致的豚鼠离体心室乳头肌自发电活动的影响。所得结果如下:(1)2mM～4mM的硫酸镁可对抗0.4μM因哇巴引起的豚鼠心室肌振荡后电位。(2)2mM～4mM的硫酸镁可抑制0.8um哇酸巴因引起的豚鼠心室孔头肌的自发电活动的频率和4相除极化速度。(3).若用硫酸镁和哇巴因同时灌注则不能诱发心室肌的后电位和自发电活动。提示硫酸镁可预防和治疗哇巴因所致的心律失常。     

基于视频的交通事件自动检测技术综述

首先从基于视频的交通事件自动检测技术所涉及的目标提取、车辆跟踪和行为理解等3个步骤中，详细地介绍和比较国际上常用的各种检测算法；其次，从背景建模和车辆阴影两个方面分析了检测算法中存在的技术难点和可能的解决方案；同时，从平均检测时间、检测率和误报率3个方面介绍该技术算法性能的评价方法。最后总结了基于视频的交通事件自动检测的相关技术，展望了该技术的发展前景。     

On the formulation of time-space prisms to model constraints on personal activity-travel engagement

The notion of time-space prisms has often been used in the context of describing activity-travel patterns of individuals. This paper presents a methodology for estimating the temporal vertices of time-space prisms using the stochastic frontier modeling technique. Observed trip starting and ending times are used as dependent variables and socio-economic characteristics and commute characteristics serve as independent variables. The models are found to offer plausible results indicating that temporal vertices of time-space prisms, though unobservable, can be estimated based on temporal characteristics of observed activity-travel patterns. Comparisons of stochastic frontier models of prism vertices and the distributions of prism vertices are presented using two activity data sets collected in the United States – San Francisco and Miami. Differences and similarities in temporal vertex locations are highlighted in the paper.     

肺结核患者红细胞免疫状态的研究

采用酵母菌花环法检测了44例肺结核患者红细胞C_3b受体活性及免疫复合物粘附量,并对其中15例进行了C_3b受体对血清免疫粘附抑制因子及促进因子反应的观察。结果表明,肺结核患者C_3b受体花环率及免疫复合物花环率均明显高于正常对照组(P0.05);与正常对照组相比,肺结核患者C_3b受体对正常人血清中的免疫粘附抑制因子的反应性无明显改变(P>0.05),而对免疫粘附促进因子反应性增强(P<0.01)。     

工程项目经济活动分析存在的问题及对 策简

开展经济活动分析,是施工企业进行经济核算、正确评估施工生产和经营活动的重要工作内容之一,被广泛运用到工程项目管理中。此文针对工程项目部管理的特点,阐述开展项目经济活动分析存在的主要问题。通过分析,提出开展项目经济活动分析的基本原则和方法,应采取的对策和措施。     

神经营养因子-3对大鼠胃肠肌电活动的影响

目的　探讨进行人重组神经营养因子 3(rh NT 3)对大鼠胃肠动力及消化间期移行性复合肌电 (MMC)的影响。方法　在大鼠的胃窦、十二指肠、空肠及结肠处手术埋植银丝电极 5～ 7d后 ,在清醒空腹状态下通过尾静脉注射2 0 μg·kg- 1 的rh NT 3或安慰剂 ,对照分析注射前后各 2h大鼠的胃肠肌电活动变化。结果　rh NT 3对胃窦及小肠处的肌电活动有增强效应 (P <0 .0 5 ) ,但对其MMCs周期无显著影响 ;在横结肠 ,rh NT 3不但可显著增强峰电的频率、振幅及延长峰电周期 ,而且可以使MMCs周期延长 [(2 5± 11)minvs.(19± 6 )min ,P <0 .0 5 ) ];在远端结肠处 ,rh NT 3打断MMC模式 ,引起类似MMCⅢ相的连续的峰电活动 ,持续约 (48± 6 )min。结论　外源性的rh NT 3对大鼠的胃肠肌电活动具有加强作用