Posttrial effects of presenting vs. omitting expected shock USs in the conditioned suppression procedure: Concurrent measurement of barpress suppression and freezing

Barpress suppression in a 1-min interval following CS trials was investigated using 16 rats in a conditioned suppression procedure with a two-stage design. For one group, each CS co-terminated with a brief shock US in Stage 1; then, in Stage 2, only half the CSs ended with a shock, which in turn was followed 1 min later by a second shock. For a second group, the two stages were reversed. When CSs were followed by single shocks in Stage 1, posttrial suppression weakened across trials; but when, in Stage 2, double shocks followed half the CSs, posttrial suppression grew stronger. When half the trials were followed by double shocks in Stage 1, posttrial suppression was maintained at initial levels but weakened in Stage 2 when single shocks followed each trial. In both stages, posttrial suppression was stronger on nonreinforced than on reinforced trials. Two factors were hypothesized to control posttrial suppression. First, posttrial suppression weakens with training under the single-shock procedure because post-shock temporal stimuli come to inhibit fear unless themselves paired with shock. Second, posttrial suppression is stronger on nonreinforced trials than on reinforced trials because freezing behaviors initiated during the CS are not disrupted by a US and so persist into the posttrial interval.     

One-trial simultaneous and backward excitatory fear conditioning in rats: Lick suppression, freezing, and rearing to CS compounds and their elements

Three experiments with rat subjects sought to enhance one-trial excitatory simultaneous and backward fear conditioning by using a two-element compound conditioned stimulus (CS) instead of only a single element. During conditioning, experimental groups received a 4-sec CS either coextensively with a 1-mA grid-shock unconditioned stimulus (US) or immediately after US termination. In subsequent tests, CSs evoked more lick suppression and freezing in these groups than in various controls. Compound CSs evoked more lick suppression and freezing than did CS elements, but did so equally for experimental and control groups. Therefore, the use of compounds did not enhance conditioning. Unexpectedly, an explicitly unpaired control in which CS followed US termination by 3 min tended to show more CS-evoked suppression and freezing than did a control in which CS preceded US onset by 3 min. This result raises the possibility that associations between the CS and the training context might engender responding to backward-paired CSs.     

One-trial excitatory backward conditioning as assessed by conditioned suppression of licking in rats: Concurrent observations of lick suppression and defensive behaviors

Twenty-eight male albino rats were given a single 4-sec 1-mA electric-grid-shock unconditioned stimulus (US). In the same session they received two 12-sec conditioned stimuli (CSs). One CS (explicitly unpaired) terminated 180 sec before the US began; the other (backward paired) began immediately after the US terminated. The CSs used were a 1000-Hz 85-dB tone and an 84-dB click; their roles were counterbalanced. Over the next 2 days, each CS was presented for 2 min while the rats drank from a water bottle. The backward-paired CS was found to suppress licking more than the explicitly unpaired CS. This suppression was accompanied by an increase in defensive behavior (freezing and freeze/nod) and by a decrease in other activity. The suppression did not seem to be due to a maintained or enhanced CS-orienting response reflex, nor could it be attributed to an adventitiously reinforced interfering operant. The results support the presumption made in previous reports that the lick suppression evoked by a backward CS reflected one-trial backward excitatory fear conditioning.     

CS modality effects in one-trial backward and forward excitatory conditioning as assessed by conditioned suppression of licking in rats

Rats received a single 4-sec 1-mA grid-shock US either preceded or followed by a 4-sec tone or light CS. Conditioning was later assessed by comparing the amount of lick suppression evoked by the forward- or backward-paired CS versus an explicitly unpaired CS. The backward-paired CS produced more suppression than the unpaired CS only when both were tone; the light evoked strong suppression whether paired or not. In the forward procedure, tone produced more suppression when paired and less when unpaired than did light; conditioning thus appeared stronger with the tone. In one experiment, observations showed that rats froze during the forward-paired tone but not during the light. Increasing CS duration from 4 to 12 sec had no effect for the forward-paired light but increased freezing to the forward-paired tone. Another experiment showed similar unconditioned suppression to tone and light but faster habituation to tone. Problems that these results create for interpreting evidence for excitatory backward conditioning in the conditioned suppression procedure are discussed.     

CS and US duration effects in one-trial simultaneous fear conditioning as assessed by conditioned suppression of licking in rats

In three experiments, rats received a single presentation of an auditory conditioned stimulus (CS) beginning simultaneously with an electric grid-shock unconditioned stimulus (US). Later, the CS was presented while the rats licked a drinking tube for water, and CS-elicited suppression of licking was taken as an index of the excitation conditioned to the CS. It was found that conditioning increased as a joint function of the duration of CS-US overlap and US duration. The evidence suggested that weak conditioning due to a brief CS-US overlap could be increased by extending the US beyond CS termination. Extending CS duration beyond US termination, however, did not strengthen conditioning; indeed, extending the CS 60 sec beyond US termination weakened conditioning significantly. It is suggested that these results shed light on a discrepancy in the recent literature on simultaneous conditioning.     

Effect of glycine site/NMDA receptor antagonist MRZ2/576 on the conditioned place preference and locomotor activity induced by morphine in mice

Objective： To study the effect of glycine site/NMDA （N-methyl-D-aspartate） receptor antagonist MRZ2/576 on the conditioned place preference （CPP） and locomotor activity induced by morphine in mice. Methods： Different doses （1.25, 2.5 and 5 mg/kg, i.p.） of MRZ2/576 were used to evaluate the effect of MRZ2/576 on the acquisition and expression of CPP induced by morphine （5 mg/kg） in mice. In addition, we examined the locomotor activity of mice in conditioning and testing phase of CPP paradigm. Results： MRZ2/576 alone could not establish place preference, but a 5 mg/kg dose of MRZ2/576 could block both acquisition and expression of morphine-induced CPP. In testing phase of CPP, there was no statistical difference for locomotor activity between the groups; injection of MRZ2/576 showed a dose-dependent decrease of locomotor activity on both control and morphine-treated mice, especially 5 mg/kg of MRZ2/576 significantly suppressed the locomotor activity of mice. Conclusion： Based on the present results, we assume that MRZ2/576 can antagonize the rewarding effect of morphine, suggesting that this glycine site/NMDA receptor antagonist could be used to treat addictions due to its light side effect profile.     

Investigating the effectiveness of a learning activity supported by a mobile multimedia learning system to enhance autonomous EFL learning in authentic contexts

A learning activity supported by a mobile multimedia learning system (MMLS) was designed in this study. We aimed to test the effectiveness of the learning activity to enhance autonomous language learning in quasi-experimental Study 1 using a pretest/posttest design. Two groups participated in the learning activity: the students in a control group (n = 27) completed the activity using traditional approach whereas the students in an experimental group (n = 26) completed the activity using MMLS. The results of Study 1 showed that the experimental students outperformed their counterparts on the post-test (F = 29.602, p < 0.005, partial eta-squared = 0.372). In a non-experimental Study 2, the experimental students (n = 26) were assigned two learning tasks, the first task was completed individually and the second task in collaboration. We aimed to investigate which learning approach to complete tasks (i.e. individual vs. collaborative) enhances learning performance better by comparing students’ scores on two tasks. In addition, we explored students’ perceptions towards MMLS. The results of Study 2 showed that the students had better learning performance when they completed tasks in collaboration than individually. The results also showed that the students had high perceptions towards MMLS. Based on our results, we make suggestions and provide directions for future research.     

Intentionality as measured in the persistence and elaboration of communication by chimpanzees (Pan troglodytes)

In human infancy, 2 criteria for intentional communication are (a) persistence in and (b) elaboration of communication when initial attempts to communicate fail. Twenty-nine chimpanzees (Pan troglodytes) were presented with both desirable (a banana) and undesirable food (commercial primate chow). Three conditions were administered: (a) the banana was delivered (successful communication), (b) half of the banana was delivered (partially successful communication), and (c) the chow was delivered (failed communication). The chimpanzees exhibited persistence in and elaboration of their communication in every condition except when the banana was delivered. Thus, their communication was about a specific item, demonstrating that both intentionality and nonverbal reference are capacities shared by humans with our nearest living relatives, the great apes.     

Content,format, gender and grade level differences in elementary students' ability to read science materials as measured by the cloze procedure

Present instructional trends in science indicate a need to reexamine a traditional concern in science education: the readability of science textbooks. An area of reading research not well documented is the effect of color, visuals, and page layout on readability of science materials. Using the cloze readability method, the present study explored the relationships between page format, grade level, sex, content, and elementary school students ability to read science material. Significant relationships were found between cloze scores and both grade level and content, and there was a significant interaction effect between grade and sex in favor of older males. No significant relationships could be attributed to page format and sex. In the area of science content, biological materials were most difficult in terms of readability followed by earth science and physical science. Grade level data indicated that grade five materials were more difficult for that level than either grade four or grade six materials were for students at each respective level. In eight of nine cases, the science text materials would be classified at or near the frustration level of readability. The implications for textbook writers and publishers are that science reading materials need to be produced with greater attention to readability and known design principles regarding visual supplements. The implication for teachers is that students need direct instruction in using visual materials to increase their learning from text material. Present visual materials appear to neither help nor hinder the student to gain information from text material.     

Resistance to discrimination and subsequent resistance to extinction as a function of the sequence of partial S+ reward in differential conditioning

The effects of transitions from nonrewarded (N) to rewarded (R) trials (N-R transitions) on discriminative behavior in differential conditioning and subsequent resistance to extinction were investigated in two experiments. In Experiment 1, groups given N-R transitions within S+ were more resistant to discrimination (ran fast in S?) and extinction than were groups given a partial reinforcement (PRF) schedule in S+ devoid of N-R transitions. Experiment 2 indicated that N-R transitions that occur when an N trial in S? is followed by an R trial in S+ are as effective in increasing resistance to discrimination, but not resistance to extinction, as are N-R transitions that occur within S+. The sequential effects obtained here were highly similar to those in conventional PRF and support the view that differential conditioning and PRF are highly interrelated phenomena. The results are discussed in terms of the extension of sequential theory to differential conditioning and the importance of internal reward-produced cues in discrimination learning.     

坚持党管人才原则 做好人才培养工作

一.“党管人才”原则的战略意义当代国家与国家之间的竞争,说到底是综合国力的竞争。综合国力的竞争本质上是人才的竞争。特别是随着上个世纪末知识经济时代的到来,国家与国家之间的人才竞争形势可以说达到了白热化的程度。在这样一种严峻的国际竞争态势下,我们党要全面贯彻“三个代表”重要思想,继往开来,与时俱进,全面建设小康社会,就必须把巨大的人口压力转化为丰富的人力资源,以人才优势赢得全球化竞争的胜利。为了适应这种新的历史形势的要求,2002年5月,党中央、国务院下发了《2002—2005年全国人才队伍建设规划纲要》,着眼于各项事业…     

The role of sex differences in the referral process as measured by the Peabody Picture Vocabulary Test-Revised and the Wechsler Intelligence Scale for Children-Revised

The Peabody Picture Vocabulary Test-Revised (PPVT-R) and the Wechsler Intelligence Scale for Children-Revised (WISC-R) are two tests that are often used in the assessment process for special education referrals. Sex differences apparent in these tests were examined in a sample of Arkansas school children who were first-time referrals for a psychological evaluation. The subjects' PPVT-R standard scores, WISC-R IQ scores, and WISC-R subtest scores were divided into groups according to one-year intervals from ages 6 through 16. A separate 2 × 11 (subjects' sex x subjects' age) analysis of variance was performed for each dependent variable. Results indicated significant sex differences among WISC-R Full Scale, Verbal, and Performance IQs and PPVT-R standard scores (p < .01). Several WISC-R subtests also revealed significant sex differences. Further significant sex differences were indicated at several age groups on each dependent variable, with males consistently scoring higher than females on 87%. of the dependent measures excluding the WISC-R subtest Coding, on which females scored higher. Implications concerning the referral process are discussed.     

益智仁水提取物对脑老化小鼠海马SOD活力及蛋白含量的影响

[目的]观察益智仁水提取物(A lp in ia oxyphylla M iq.fru it,AOF)对脑老化小鼠海马SOD活力及海马蛋白含量的影响.[方法]选用健康成年昆明种小鼠60只,雌雄各半,随机数字表法将其分成5组:对照组、模型组、脑复康组、AOF低剂量组、AOF高剂量组.用D-半乳糖皮下注射诱导小鼠脑老化模型,采用学习记忆行为训练和生化测定结合的方法,观察AOF对小鼠学习记忆能力的影响,测定海马组织超氧化物歧化酶(SOD)和海马蛋白含量.[结果]①AOF对脑老化小鼠学习记忆能力的影响:模型组达标所需训练次数显著高于对照组(p<0.01),AOF低、高剂量组达标所需训练次数显著低于模型组(p<0.01).②AOF对脑老化小鼠海马SOD活力的影响:模型组小鼠海马SOD活力显著低于对照组(p<0.05),AOF低、高剂量组小鼠海马SOD活力显著高于模型组(p<0.05).③AOF对脑老化小鼠海马蛋白含量的影响:与对照组比,模型组小鼠海马蛋白含量显著降低(p<0.01);与模型组相比,AOF低、高剂量组小鼠海马蛋白含量显著增高(p<0.01).[结论]AOF可提高脑老化小鼠海马SOD活力,增加海马蛋白含量,对D-半乳糖诱导脑老化小鼠的学习记忆障碍具有显著的改善作用.     

政府推动市场导向努力把德阳建成中国西部职业教育基地

德阳是全国重大装备制造业基地,拥有中国二重、东方电机和东方汽轮机等一批关系国家经济命脉的重点骨干企业,生产的大型发电设备和轧钢设备占到全国总产量的三分之一.近年来,在四川省委、省政府的有力推动下,我们把职业教育作为推进德阳跨越式发展的重要抓手,坚持政府推动与市场导向相结合,像抓经济工作一样抓职业教育,努力推进西部职业教育基地建设,实现了职业教育与经济发展的和谐互动.     

Might It Be in the Practice that It Fails to Succeed? A Marxist Critique of Claims for Postmodernism and Poststructuralism as Forces for Social Change and Social Justice

In this paper I begin by taking a brief glimpse at the current state of global capitalism. I then look at attempts in Britain and the US to argue the case, within educational theory, that postmodernism and poststructuralism can be forces for social change and social justice. Concentrating on some of the work of Elizabeth Atkinson, Patti Lather and Judith Baxter, I argue that such claims are illusory. I make the case that Marxism remains the only viable option in the pursuit of social change and social justice.     

农科教统筹多部门配合推动乐山百万劳动力转移

乐山市地处川南,总人口347万,辖11个区、市、县,有农村人口267万,其中,18～50岁劳动力150余万.为了加快全市经济结构和产业结构的战略调整,实现地方经济跨越式发展,市委、市政府2003年初就提出"转移农村劳动力100万"的目标.     

扎实开设安全教育课程势在必行——有感于桑枣中学师生在汶川地震中无一伤亡的奇迹

学校是汶川大地震生命损失的重灾户,但桑枣中学2300多名师生无一伤亡。通过对这一典型案例的分析,指出学校安全教育需要强化三个方面内容:校长必须保证加强安全教育的执行力;制订学校安全教育的国家课程标准;扎实开展学校安全教育。