State-dependent retention induced by postacquisition exposure to pentobarbital or shock stress in rats

Although state-dependent retention (SDR) has been the focus of considerable research in recent years, there has been little work demonstrating this phenomenon when the treatment is administeredafter learning. In the present study, the effectiveness of two different treatments, pentobarbital and shock-induced stress, in producing postacquisition SDR in rats was examined. In all experiments, water-deprived rats were exposed to a novel flavor, apple juice, on each of 2 days. Subjects that remember their initial exposure to this substance should show an increase in consumption on their second exposure (i.e., an attenuation of neophobia). It was found that subjects exposed to pentobarbital (Experiment 1) or shock-induced stress (Experiment 2) immediately after their initial exposure did not increase their intake on the subsequent exposure unless they were reexposed to pentobarbital (Experiment 1) or shock-induced stress (Experiment 2b) shortly prior to that exposure. These results clearly show that this “attenuation of neophobia” paradigm can be used to investigate postacquisition SDR.     

The overshadowing of background stimuli by an informative CS in aversive Pavlovian conditioning with rats

Two experiments investigated the capacity of a nominal CS to overshadow background stimuli. Rats received CS-shock pairings in one compartment of a double-compartment apparatus. After training, the shock compartment was re-presented but in the absence of both the CS and shock, and overshadowing was assessed by measuring the rats’ latency to enter the compartment. In the first experiment, predictive values of temporal cues provided by CS onset and CS offset were manipulated. Rats readily entered the shock compartment, provided shock onset had previously been predicted by CS onset or CS offset. This indicates that background cues in the shock compartment had acquired little associative strength during training. In contrast, rats avoided the shock compartment under every condition in which shock onset had not previously been predicted by either CS onset or CS offset. In the second experiment, a precise temporal cue provided by CS onset was dissociated from other factors arising from CS-shock contiguity. It was found that rats’ reactions to the shock compartment after training was governed by both temporal and contiguity factors. The results are relevant to theories which state that conditioning is a function of a competitive relationship between stimuli present in an animal’s environment during training.     

基于行动研究的大学与中小学联合培养教育硕士模式初探

大学与中小学联合培养教育硕士,是一种以标准化的行动研究流程为基础,以大学与中小学合作为核心,以反思为主线的新型教育模式,具有务实性、合作性、创新性等特点,因而有利于打造＂双师型＂指导教师队伍,实现教育硕士培养目标。在实际操作中,参与各方要围绕＂确定问题＂和＂采取行动＂两个重点环节开展工作,教育硕士生应加强理论学习,着力提高发现及分析解决问题的能力,有关单位要精心制定行动计划,尽可能使学员的研修内容和形式互为一体。     

液相色谱-串联质谱/质谱法联用检测鸡蛋与蛋制品中的三聚氰胺

建立了检测鸡蛋中三聚氰胺的超高效液相色谱-串联质谱/质谱法.样品用三氯乙酸溶液提取,经阳离子交换固相萃取柱净化后,用液相色谱-串联质谱/质谱法测定和确证,在电喷雾离子化(ESI+)和多反应监测模式条件下,外标法定量.结果表明:该方法线性好,三聚氰胺的线性范围为10～200 μg/L;线性相关系数分别为0.999 9,检出限为0.01 mg/kg;在3个浓度水平加标,三聚氰胺的回收率在85.4%～98.5%之间,变异系数小于10%.该方法灵敏度高、准确度好,非常适用于鸡蛋与蛋制品中三聚氰胺的检测.     

当代大学生知行取向分析及对策——以"大学生与社会协调发展"课题组调研为例

正确的知行取向是大学生与社会协调发展的基础和表现.文章从大学生认知取向、价值取向、行为表现等3方面对当代大学生知行取向主要特点进行探讨,并就其偏差的成因进行分析,进而提出了大学生如何确立正确的知行取向,促进自身与社会协调发展的对策.