Spatiotemporal characteristics of serial CSs and their relation to search modes and response form

In four experiments, we examined how the spatiotemporal proximity to food of the two elements of a serial conditioned stimulus (CS) influenced the pattern of CS-directed versus food-site-directed behavior in rats. Experiment 1 showed that only temporal proximity affected responding when the serial CS consisted of two successive 4-sec presentations of either a spatially near or a spatially far lever (NN or FF). However, Experiment 2 showed that behavior depended markedly on whether rats received a near followed by a far lever (NF) or a far followed by a near lever (FN). Experiment 3 showed that the effects of Experiment 2 could be changed by increasing the duration of the second CS element, and Experiment 4 showed that these changes were not related to previous training. We concluded that behavior produced by the spatiotemporal qualities of the lever elements can be attributed to a mapping between the temporal qualities of the CS elements and an underlying sequence of search modes related to finding food.     

Blocking and enhancement of fear conditioning by appetitive CSs

Prior research on Pavlovian-to-instrumental transfer has shown that when a CS previously associated with shock (AvCS+) is presented contingent upon a choice response to a discriminative stimulus for food reinforcement, it facilitates discrimination learning. Conversely, a response-contingent CS previously associated with the absence of shock (AvCS?) retards discrimination learning. To evaluate whether these findings reflect across-reinforcement blocking and enhancement effects, two experiments investigated the effects of appetitively conditioned stimuli on fear conditioning to a novel stimulus that was serially compounded with the appetitive CS during conditioned-emotional-response (CER) training. Although there were no differential effects of the appetitive CSs in CER acquisition, Experiment 1, using a relatively weak shock US, showed that a CS previously associated with food (ApCS+) retarded CER extinction to the novel stimulus, in evidence of enhanced fear conditioning to that stimulus. In addition, Experiment 2, using a stronger shock US, showed that a CS previously associated with the absence of food (ApCS?) facilitated CER extinction to the novel stimulus, in evidence of weaker fear conditioning to that stimulus. These results parallel traditional blocking effects and indicate not only that an ApCS+ and an ApCS? are functionally similar to AvCSs of opposite sign, but that their functional similarity is mediated by common central emotional states.     

用初等方法求一个无穷级数和

文中用初等数学方法求得一个无穷级数的和。     

一类幂级数求和方法及其应用

文章给出一类幂级数求和的方法,并用此解决了此类级数求和的问题。     

总结历史经验加强新时期思想政治工作

认真总结党在思想政治工作中的历史经验对今天搞好思想政治工作有着重要的借鉴价值.我们应正确估价思想政治工作的地位和作用,防止出现教育内容与群众实际相脱节,在思想政治工作中做到平等、沟通、理解、信任,注重思想政治工作形式和手段的创新.     

A behavior systems view of responding to probe stimuli during an interfood clock

Two experiments used a behavior systems approach to relate the form of responses during an interfood clock to the temporal distance of the individual clock stimuli to food. Stimuli proximate to food should better control a focal search mode and related responses, whereas stimuli temporally distant from food should better control a general search mode and related responses. Experiment 1 conditioned two groups of rats with a sequence of four equal-length 12-sec clock stimuli that terminated with food and then tested for the conditioning of a general search mode by presenting an unconditioned moving probe stimulus (either a rolling ball bearing or a rotating mechanical door) during each of the clock stimuli. Consistent with a behavior systems view, contact with the ball bearing was markedly greater during a clock stimulus distant from food. The absence of similar differential contact of the door across the clock stimuli showed that the effect was specific to the ball bearing rather than a general response to stimulus dimensions of movement and sound. Experiment 2 showed that the general search mode was controlled by the clock stimulus rather than the passage of time.     

朱载堉十二平均律求方积辨析——《密率求方积第四》释解

文章通过对朱载靖《律学新说》“密率求方积第四”前言的释解,以现代数学的方法解诠释了各律之间的体积运算,诠释了朱载靖圆周率和祖冲之圆周率的数据比值,并将朱π和祖π进行了误差演算比较,从而求证了黄钟体积运算和相邻二律之间体积之比值数据,详细地诠释了。朱载靖求方积的密率之法。     

Identifying and responding to needs in education

Do educators know what children need? Most of the school curriculum is supported by the assumption that educators and policymakers do indeed know what children need, and the curriculum is designed to satisfy these inferred needs. In trying to meet inferred needs, however, we often neglect the expressed needs of our students. Sometimes, of course, we rightly fear that expressed needs are mere momentary desires and that they should be curbed and replaced by the important needs we have already identified. But often, by ignoring expressed needs, we sacrifice opportunities to develop individual talents, intrinsic motivation, and the joys of learning. In this article, I explore the nature of needs and ways in which schools might better identify and respond to them. I start with a brief discussion of care ethics because it, in contrast to the dominant ethics of justice, gives attention to needs before moving on to matters of justice.     

湖南农业应对WTO之策略

本文对中国加入WTO后,湖南农业存在的问题进行剖析,指出入世给湖南农业带来的压力和相应机遇,提出了湖南农业走出困境、冲出湖南、走向世界的对策与措施。     

Students' conceptions of learning in an engineering context

Research on student learning in higher education has highlighted the central role that students' conceptions of learning play in influencing their approaches to learning. This article reports on a study of conceptions of learning among engineering students on a one-year foundation course. Students were interviewed about their conceptions of learning at three intervals during their academic year. The data was analysed using a phenomenographic perspective and from the data five qualitatively different conceptions of learning were identified. The resulting characterisation of these conceptions of learning is presented using excerpts from the interviews and some implications for student learning are discussed.     

The effects of Pavlovian CSs on two food-reinforced baselines— with and without noncontingent shock

Two experiments explored the effects of Pavlovian (tone-shock) CS+, CS?, and truly random control (TRC) contingencies on two different food-reinforced instrumental baselines. One food-reinforced baseline contained noncontingent shock, while the other did not. In the first experiment, a TRC contingency was shown to produce suppression of food-reinforced responding, while a CS? contingency did not. When noncontingent shock was added to the baseline, however, the TRC stimuli failed to produce suppression, and the CS? contingency increased response rates over baseline level. In a second experiment, the effects of TRC and CS+ contingencies were compared on these same two baselines. While the CS+ produced suppression on both shock and no-shock baselines, the TRC contingency again produced suppression on only the no-shock baseline.     

考研数学中的幂级数求和一题多解

幂级数求和是考研数学中的一个重要内容,也是学生学习中普遍感觉比较困难的知识点。文章以近几年数学考研试题中的幂级数求和问题为例,采用一题多解的形式,介绍了求幂级数和函数的三种常用方法。     

语境对翻译的制约与操控

语境(context)这一术语最初是由英国人类学家Bronislaw Malinowski(B.马里诺夫斯基)在1923年提出的。从语境研究的历史现状来看,各门不同的学科以及不同的学术流派关于语境的定义及其基本内容并不完全相同。本文拟从"语言性语境"和"非语言性语境"两大方面阐释其对翻译的制约和操控作用。其中非语言性语境是侧重点,主要包括三方面——社会背景,文化背景,意识形态。     

Sorcery and SSCEP: the cultural context of an educational innovation

The paper highlights the relative neglect by educational planners of a socio‐cullural analysis of the context surrounding the implementation of educational reforms designed to promote rural development in Third World countries. An examination of the sociological and anthropological literature pertaining to both village culture and rural development in Papua New Guinea suggests that there are powerful cultural constraints on schools leavers applying practical skills learned in school on their return to the village. These are exemplified by a discussion of the role of sorcery, the subordinate position of youth, and the divergence between planners’ and villagers’ priorities, and are illustrated with reference to the Secondary Schools Community Extension Project (SSCEP).     

Tutor learning: the role of explaining and responding to questions

Previous research on peer tutoring has found that students sometimes benefit academically from tutoring other students. In this study we combined quantitative and qualitative analyses to explore how untrained peer tutors learned via explaining and responding to tutee questions in a non-reciprocal tutoring setting. In support of our hypotheses, we found that tutors learned most effectively when their instructional activities incorporated reflective knowledge-building in which they monitored their own understanding, generated inferences to repair misunderstandings, and elaborated upon the source materials. However, tutors seemed to adopt a knowledge-telling bias in which they primarily summarized the source materials with little elaboration. Tutors’ reflective knowledge-building activities, when they occurred, were more frequently elicited by interactions with their tutee. In particular, when tutees asked questions that contained an inference or required an inferential answer, tutors’ responses were more likely to be elaborative and metacognitive. Directions for future research are also discussed.     

A test of anxiety/uncertainty management theory: The intercultural adaptation context

Anxiety/Uncertainty Management theory, as formulated by Gudykunst and Hammer (1987a), proposes that intercultural adaptation outcomes are based on the two mediating dimensions of uncertainty reduction and anxiety reduction and sixteen secondary variables that systematically influence uncertainty and anxiety reduction. In this paper, the sixteen variables originally identified are categorized into four “fundamental factors”; (interpersonal saliencies, intergroup saliencies, communication message exchange, and host contact conditions). The present study examines this revised Anxiety/Uncertainty Management (AUM) theory of intercultural adaptation. A total of 291 international students at two universities in the United States participated in the study. The study found overall fit of the revised AUM theory vis‐a‐vis the two mediating factors of uncertainty and anxiety reduction, the importance of interpersonal saliencies for uncertainty reduction, and the importance of host contact conditions for facilitating feelings of comfort and reducing anxiety. Intergroup saliencies were significantly related to uncertainty reduction but not, contrary to expectation, to anxiety reduction. Communication message exchange (which consists of information gathering strategies and second language proficiency) was, again contrary to expectation, not significantly related to either uncertainty or anxiety reduction. Finally, cultural identity showed a small though significant negative relationship to intergroup saliencies, suggesting a stronger, ingroup identity was associated with increased uncertainty. The paper concludes by proffering explanations for the findings and suggestions for future research.     

The use of Lawson's test of formal reasoning in the Israeli science education context

Lawson's test of formal reasoning was used in the Israeli educational context in order to investigate the relationship between students' achievement in science and in mathematics, to compare the performance of boys and girls, and to compare the performance of Israeli and U.S. populations. It was found that, in general, boys outperform girls; there is only a small correlation between achievement in science and math and Lawson test; and that the Israeli population achieved significantly higher than the U.S. population on the Piagetian skills measured by the test: It was concluded that the future use of Lawson's test by the high school teacher is doubtful.