A test of the conservation model for autoshaped leverpressing and polydipsia in the rat

This study examined a conservation model (Allison & Mack, 1982) that predicts a linear relation between the weighted sum of two responses, autoshaped leverpressing and polydipsia, and the amount of food delivered on a variable-time schedule. Fifteen rats were assigned randomly to one of three groups. The rats in Group 1 were maintained at 80% of their free-feeding body weights. Those in Group 2 began at 100% but were allowed to lose weight during the experiment. The rats in Group 3 also began at 100% of their free-feeding weights and were maintained at this level. Each group was exposed to five conditions that delivered less food than that consumed during baseline and to one condition that delivered more food. The results did not support the conservation model. Contrary to the model, the decreasing linear relation between the individual responses, or the weighted sum of the responses, and the amount of food delivered was not found for all rats, and some rats responded more when an excessive amount of food was presented than during baseline.     

Systematic manipulation of CS-US pairings in negative CS-US correlation procedures in rats

Male albino rats were exposed to negative correlations of tone CSs and shock USs. When the number of CSs and unpaired USs was held constant, the ability of the CS to resist subsequent excitatory conditioning declined as a function of the number or proportion of CSs paired with USs; so, too, did the ability of the CS to disrupt excitation to a second CS. In one treatment, in which the rate of USs in CS presence approached that in CS absence, the CS significantly enhanced excitation to a second CS. It is concluded that the rate of USs in CS presence need not be zero for a negative correlation to produce inhibitory effects. Also discussed is the possibility that positive and negative correlation procedures may have asymmetrical effects, at least preasymptotically.     

Within- and between-subjects partial reinforcement effects with an autoshaped response using Japanese quail (Coturnix coturnix japonica)

Animals exposed to schedules of partial reinforcement are typically more resistant to extinction than are animals trained with continuous reinforcement. This is the partial reinforcement effect (PRE). Animals experienced with both partial and continuous schedules are often more persistent on the continuous schedule, yielding a reversed PRE. Both conventional and reversed PREs have been elusive with classical conditioning paradigms. The present experiment attempted to demonstrate between- and within-subject PREs using 50% and 100% autoshaping schedules. Presence or absence of a PRE depended on the behavioral measures used. Marked terminal group differences in acquisition produced a between-subjects PRE with absolute response levels but not with rate-of-change measures. Within subjects, only choice trial comparisons were sensitive enough to differentiate the two schedules. Acquisition data were inconsistent with most of the classical conditioning PRE literature, but consistent with results reported in the autoshaping literature. These discrepancies may reflect the operant-classical interaction in autoshaping.     

Blocking in landmark-based search in honeybees

Two experiments tested blocking in landmark-based search in honeybees. Honeybees in the experimental group were trained in Phase 1 with a single landmark in a constant spatial relation to the target (sugar water). In the compound training second phase, the landmark used in Phase 1 (blocking landmark) and a new landmark (blocked landmark) were presented at constant spatial relations to the target. The blocking and blocked landmarks differed from each other in color and position, and the blocking landmark retained the same spatial relationship to the target as in Phase 1. In Experiment 1, the control group experienced only Phase 2 training with two landmarks. In Experiment 2, the control group was trained with a different landmark in a different position in Phase 1. Blocking was found in both cases.     

Blocking with serial and simultaneous compounds in a trace conditioning procedure

Blocking of conditioned suppression in rats was studied in three experiments using serial and simultaneous compounds in Pavlovian trace conditioning procedures. Experimental groups were first given trace conditioning trials with a 2-sec stimulus (A) presented at least 60 sec before an electric grid shock US. Next, both experimental and control groups received reinforced trials with a compound stimulus (AB). Both A and B were 2 sec in duration and were presented at least 60 sec before the US. For some groups during AB training, the A stimulus preceded the B stimulus; for others, B preceded A; for still others, A and B occurred simultaneously. Conditioning was subsequently assessed separately to both A and B. The results were as follows: First, varying the interval between the onset of A and the US during A training appeared to produce significantly different levels of conditioning to A but did not detectably affect A’s ability to block conditioning to B. Second, blocking was observed in both simultaneous and serial procedures. Third, in the serial procedure, A blocked conditioning to B whether it preceded B or followed B in the AB compound. Fourth, in tests given after AB conditioning, the experimental and control groups suppressed similarly to A. The relevance of these results to the conditioning model of Rescorla and Wagner (1972) and to Mackintosh’s (1975b) theory of attention are discussed.     

含过程程序的单子切片

为解决含过程程序的单子切片问题,提出基于回填待定标号的两阶段单子切片算法．算法第1阶段用给定标号初始化子过程的形参切片表,并通过分析调用语句捕获被调者对调用者的影响．算法第2阶段主要是通过回填切片表中相应的待定标号来捕获施调者对被调者的影响．待定标号的引入使得所提切片算法可捕获类似基于系统依赖图（SDG）切片算法中的概要信息,且也可避免上下文调用问题．借助于切片单子转换器,所提单子切片算法将具有较高的模块性和适应性,且其复杂度不劣于基于SDG的切片算法．     

Blocking despite changes in reinforcer identity

Rats were trained on a discriminated operant barpressing task according to a standard blocking design. In some conditions, the reinforcer was changed between the pretraining and compound conditioning phases; for other conditions, the reinforcer remained the same across phases. In three separate experiments using both between- and within-subject designs, strong blocking effects occurred regardless of the change in the reinforcer. In a fourth experiment, a multiple schedule of reinforcement was used in which response-independent reinforcers were superimposed on the schedule of response-contingent reinforcers. The degree of response suppression caused by the free reinforcer was greater when the free reinforcers were the same as the response-contingent reinforcers than when they were different. The role played by the reinforcer identity in contingency experiments thus appears to be different from the role it plays in blocking experiments.     

Blocking of conditioned suppression with 1 or 10 compound trials

It is generally agreed that the Kamin blocking effect provides a differential test of the model of classical conditioning proposed by Rescorla and Wagner (1972), on the one hand, and the models proposed by Mackintosh (1975) and Pearce and Hall (1980), on the other. Specifically, if the blocking effect occurs with 1 compound trial, Rescorla and Wagner are supported. Experiment 1 showed that prior training with one element of a simultaneous compound stimulus prevented the added element from becoming conditioned with 10 compound trials when compared with a nonpretrained (Kamin) control. A pseudoconditioning control, which received no compound training, showed substantial suppression only on the first trial. A contextual conditioning control, which received unsignaled shock prior to compound training, was suppressed, suggesting a failure of conditioning to contextual cues. Experiment 2 demonstrated 1-compound-trial blocking using a simultaneous presentation of the compound elements. The importance of this support for the Rescorla-Wagner model is discussed in the light of other supportive studies and those which support alternative models of classical conditioning.     

Blocking student performance in high school?

Block schedules have been used in several different high schools in various areas of the United States. Reasons for their use vary from better preparing students for college work to fewer disruptions of the school day. Several studies have examined the impact of changing from a semester system to a block system on the academic performance in specific areas with varying results. This paper examines the impact of a change of schedule on overall academic performance as measured by a student’s Grade Point Average. This study indicates that for the specific case studied, the change in systems did have a positive effect on performance.     

Ad hoc网络中带有DoS阻断功能的密钥管理策略

在Ad hoc网络中密钥的安全问题已经成为研究热点,本文首先对存在的安全隐患进行了分析描述,然后从节点间信任角度出发,结合Ad hoc网络自身特点,提出了一种带DoS入侵阻断功能的分布式密钥管理策略,用于保证整个网络的安全性,提高了网络性能。     

Blocking of first- and second-order autoshaping in pigeons

In Experiment 1, the development of autoshaped pecking to a keylight signaling food was blocked if the keylight was presented only in conjunction with another stimulus already established as a signal for food, even though the blocking stimulus (either an overhead light or a train of clicks) never elicited pecking itself. In Experiment 2, pigeons came to peck a white keylight which signaled the presentation of a red keylight which had earlier been established as a first-order signal for food, but this second-order autoshaping was blocked if the white keylight was presented only in conjunction with the houselight or clicker which had previously signaled the presentation of the first-order stimulus. Second-order autoshaping was thus blocked in the same way as was first-order autoshaping.     

Excitatory and inhibitory consequences of explicitly unpaired and truly random conditioning procedures on heart rate in rats

A comparison was made of heart-rate (HR) responses of restrained rats to CSs that were part of an explicitly unpaired or a truly random control procedure. Subsequent to these procedures, an assessment was made of the relative capacities of these CSs to affect an established HR CR in a combined-cue paradigm and to impede the development of a HR CR in a reversal-conditioning situation. The principal findings were (1) that the explicitly unpaired and truly random CSs generated HR responses of opposite direction, i.e., HR acceleration vs. HR deceleration, respectively, and (2) that conditioning of a decelerative HR CR to the CS that had earlier been employed in the explicitly unpaired procedure was retarded compared to what was obtained to the truly random CS. The two CSs did not have reliably different effects in the combined-cue test. It was suggested that the truly random CS may have produced both associative and nonassociative influences on HR. It was hypothesized further than the explicitly unpaired CS may have acquired the capacity to function as a conditioned inhibiting stimulus.     

专业设置、课程体系模块化与跨专业学习

在专业的设置上 ,一直存在两种观点 :一种主张专业应分得较粗略 ,涵盖面要宽些 ;一种则主张专业应分得细些。所谓专业应分得较粗略 ,首先是反映在专业名称上 ,即专业名称在含义上要更宽泛、外延更大一些 ,如机械工程专业、电气工程专业 ,等等。其次是在课程体系设置上 ,尽量把专业基础课的分量加大 ,减少或淡化专业课的含量。持这种观点的人士认为 ,粗略处理能使学生更好地适应社会的要求 ,对学生的就业、工作机会的把握有好处。所谓专业应分得较细 ,首先也是反映在其专业名称上 ,如 ,冶金机械专业、矿山机械专业、农业机械专业、焊接专业 ,…     

热水采暖系统堵塞现象的分析

采暖系统中，异物堵塞是常见的系统不热故障之一，它分为气堵与物堵两种，处理不好，将影响整个系统的采暖效果和正常使用，关系到千家万户的生活。     

Investigation of learning measures as screening procedures with kindergartners

Four repeated measures approaches to assessment were tested for their relationship to intelligence test scores, teacher ratings, and two criterion-referenced measures. One hundred and eighteen kindergarteners were tested, using one of the four procedures. Simple correlational analysis indicated that although last-day scores generally improved predictability over first-day scores, this improvement was not statistically significant. The educational usefulness of these procedures was questioned, due to relatively low correlations.     

试论争夺防守篮板球中的抢位与挡人技术

在篮球比赛中篮板球控制的好坏,是影响胜负的关键,若进攻时抢篮板球占优势,就能增加进攻次数和篮下得分机会,增强外线中投的信心和勇气,从而减少对方发动快攻的机会.防守时抢篮板球占优势,不仅可以中断对方的连续进攻,造成对方外线中投的心理障碍,亦能为本队组织快攻创造先决条件.     

篮板球抢位挡人技术分析与训练

抢篮板球在篮球比赛中是非常重要的技术,篮板球控制的好坏,对比赛胜负起着很大的作用。篮球比赛中如果进攻时抢篮板球占优势,不仅可以增加进攻次数和篮下得分的机会,而且可以增强外线中投的顾虑,而且还能为本对发动快攻创造有利的条件。