Rapid odor perception in rat olfactory bulb by microelectrode array

Responses of 302 mitral/tufted (M/T) cells in the olfactory bulb were recorded from 42 anesthetized freely breathing rats using a 16-channel microwire electrode array. Saturated vapors of four pure chemicals, anisole, carvone, citral and isoamyl acetate were applied. After aligning spike trains to the initial phase of the inhalation after odor onset, the responses of M/T cells showed transient temporal features including excitatory and inhibitory patterns. Both odor-evoked patterns indicated that mammals recognize odors within a short respiration cycle after odor stimulus. Due to the small amount of information received from a single cell, we pooled results from all responsive M/T cells to study the ensemble activity. The firing rates of the cell ensembles were computed over 100 ms bins and population vectors were constructed. The high dimension vectors were condensed into three dimensions for visualization using principal component analysis. The trajectories of both excitatory and inhibitory cell ensembles displayed strong dynamics during odor stimulation. The distances among cluster centers were enlarged compared to those of the resting state. Thus, we presumed that pictures of odor information sent to higher brain regions were depicted and odor discrimination was completed within the first breathing cycle.     

嗅觉生理发生机制的探析

嗅细胞的气味受体捕捉气体分子,激活特异性的G蛋白,把气味信号转换成动作电位,沿嗅觉传导通路传输到嗅皮层,最后大脑完成对气味信号的整理和识别作用,形成对气味的感受.一个嗅觉细胞表达一种气味受体,人类约有350个气味受体基因.嗅觉系统采用受体组合的方式对气味分子进行编码,可感受10000种以上彼此不同的气味分子.对复杂的嗅觉系统的研究有助于阐明整个感觉系统的工作原理.     

高校投影仪灯泡再生利用调查与研究

伴随着数字化教学的广泛普及,高校更换下大量的投影仪废旧灯泡,作为可再生利用物品未得到合理的利用与管理,造成严重的市场混乱和管理困扰,因此迫切需求有效的再生利用方案。该研究通过文献法、访谈法、问卷调查法等研究方法调查了浙江省高校投影灯泡的管理现状,基于调查情况设计出高校投影灯泡再生利用模式与平台。     

变温非线性粘弹性理论及其在显像管玻壳模具设计中的应用

指出了热粘弹性材料在变温和恒温下的松弛的差别 .为考虑材料在较高温度下 ,不同的应力增量沿不同的应力松弛曲线松弛的非线性现象 ,建立了一种变温非线性粘弹性理论 (该理论基于作者已建立的变温线性粘弹性理论中的一些概念 ,如材料在恒温下的松弛曲面 ,变温松弛曲线以及终态温度等效松弛曲线等 ) .该变温非线性粘弹性理论已用于模拟显像管玻壳模具的变形 ,结果表明它比基于线性理论的分析有更高精度     

大蒜幼小鳞茎细胞分裂方式的研究

幼嫩大蒜瓣的生长十迅速，是研究细胞分裂的好材料，本文就大蒜鳞茎的细胞分裂时间、方式和特点作了详尽的细致的分析探讨，发现无丝分裂是大蒜鳞茎快速生长时期的主要细胞分鲜明方式。     

Demonstration model of self inductance using relay

Using an electrical component like a relay, the phenomenon of self inductance caneasily be demonstrated to undergraduate students. By wiring simple electrical components like relay, neon bulb and a DC power supply, intermittent back electromotive force (emf) can be generated in the range from 60 to 100 volt. The glowing of neon bulb provides visual evidence for the generation of large back emf due to self inductance.     

PLC在料浆系统中的应用

结合玻壳研磨料浆系统的工作过程、控制特点,介绍了一种基于PLC的料浆控制系统的开发与实现。该系统运行稳定可靠。     

A developmental analysis of early time concepts: the equivalence and additivity of the effect of interfering cues on duration comparisons of young children

Young children compare durations correctly and explain their conclusions logically only when no interfering cues such as distance and speed are introduced. We investigated whether type of cue and additivity of interfering cues affect children's duration comparisons. 4- and 5-year-old children were asked to compare the burning times of pairs of partially synchronous lights differing in intensity, bulb size, or both. Those who erred tended to attribute longer duration to the brighter or larger bulb, brightness having a stronger interfering effect than size. Since brightness might qualify as "work" more than bulb size might, the finding that the former interferes more than the latter supports Piaget's basic claim of children's confusion of time with "work." The fact that bulb size interferes at all, which does not fit into Piaget's framework, may be explained in terms of children's inability to distinguish clearly between time-related and time-unrelated cues and their assumption of direct relations between dimensions. Additivity of interference did not emerge, indicating that the previous finding which suggested its existence--distance plus speed interfering with duration comparisons more than speed alone--should be reassessed in terms of type of interfering cues, that is, distance interferes more than speed with time.     

浅谈大型灯泡贯流机组励磁产品质量控制

本文介绍了大型灯泡贯流机组#1机励磁产品质量控制过程和要点,大型灯泡贯流机组#1机励磁产品已通过调试,证明其制造及质量控制措施是可行的．     

The influence of olfactory context on Pavlovian conditioning and its expression in preweanling (16-day-old) and adult rats

In a series of experiments, we tested the responses of preweanling (16 days postpartum) and adult rats to a specific olfactory context that was present during conditioning and testing of a brightness-location aversion. The first set of experiments established that (1) contrary to previously published effects with other distinctive contexts during conditioning and testing, a novel olfactory context impaired conditioning and its expression in preweanlings; (2) if the preweanlings were previously familiarized with the olfactory context, its presence impaired neither conditioning nor its expression; and (3) although conditioning in the absence of the olfactory context was equivalent for adults and preweanlings, the novel olfactory context had no effect on conditioning or its expression in adults. In the next set of experiments, we tested whether a conditioned aversion had been formed to the olfactory context. It was determined that although preweanlings acquired a substantial aversion to the olfactory context, whether novel or familiar, adults gave no indication of conditioning to the novel olfactory context. A final set of experiments established that preweanlings acquired an association between (or unitized) the CS + and the context. These results add to previous indications that preweanlings may be especially sensitive to redundant or irrelevant features of the conditioning episode.     

扫描电镜＋能谱系统在彩色显像管玻壳生产中的应用

本文描述了一种在现代玻壳制造技术中对玻壳玻璃缺陷进行判断和分析的有效方法。将扫描电镜技术与能谱技术有机地结合起来,对玻璃缺陷形貌和成分的双重分析,使玻璃缺陷分析更为有效、快速、准确。并列出了部分实例,有力地证明了该方法的实用性。     

百合摘顶处理对鳞茎发育的影响

顶技术处理百合，不仅使鳞茎周径增大、鲜重明显增加，而且顶以后植株地上茎增粗，叶片变大变厚．实验结果表明，百合植株从显现花蕾至花蕾5cm长这段时间顶对增加百合鳞茎的大小和重量效果好，过早或过迟顶效果均不佳．     

Hamsters remember spatial information derived from olfactory cues

A dishabituation paradigm was used to study hamsters’ memory for the spatial arrangement of olfactory cues. In Experiment 1, the animals dishabituated to a change in the positions of two different olfactory cues, but this experience did not reveal whether the response was based on egocentric (body-centered) or allocentric (body-independent) spatial information. In Experiment 2, the same dishabituation resulted when the experimental procedure required the animals to use spatial information that was independent of body position. Thus, hamsters remember the locations of olfactory cues with reference to a stable spatial framework. The dishabituation paradigm used here is a valuable tool for the study of animal spatial cognition, since it requires no explicit training and allows each animal to be tested in a relatively short experimental session.     

Prospective elementary teachers' prior knowledge about light

This article reports on a study that was designed to describe prospective elementary teachers' prior verbal and diagrammatic knowledge about various aspects of light, seeing, shadows, and mirror images. Data were collected through individual interviews using simple apparatus (light bulb, objects, screen, and plane mirror). Included are some inferences about how students' ideas may have emerged from their interpretations of everyday experiences. The article concludes with a section that provides an example of a conceptual change instructional strategy that was based on the research results reported here.     

Conditioned cardiac and behavioral response topography to an olfactory CS dissociates with age

Conditioned cardiac and behavioral responses to an olfactory stimulus (CS) paired with electric shock (US) were studied in 16-, 23-, and 75-day-old rats. Heart rate and behavior were recorded during a single 15-trial training session in which a 10-sec olfactory stimulus (amyl acetate) was either paired or explicitly unpaired with the US. In the preweanling rats, the conditioned cardiac response consisted of anincrease in heart rate (tachycardia) and a slight increase in investigatory behaviors. In contrast, the conditioned cardiac response in the adult rats consisted of adecrease in heart rate (bradycardia) and a striking increase in behavioral immobility (freezing). The 23-day-old rats showed a dichotomous pattern of responding; some showed preweanling-like conditioned responses and some showed adultlike responses. Developmental changes in neural organization and degree of learning are discussed as possible determinants of the transition from infant to adult modes of responding.     

基于人的知觉环境研讨医院环境人性化设计

医学模式的变化,引起了医院建筑功能的改变.重视医疗环境质量已成为现代医院的重要特征.文章以人对环境的知觉感受为依据,从医院的视觉环境、听觉环境和嗅觉环境等方面,探析了医院环境人性化的设计.     

Attractiveness of lactating females' breast odors to neonates

A series of experiments investigated the responses of human infants to olfactory cues produced by lactating females. 2-week-old bottle-feeding girls oriented preferentially to the breast odor (odorized pad) of a nursing woman when paired with such odors from either a nonparturient female or axillary odors from the same lactating female. Responses to axillary odor from a lactating female did not differ from those to a clean (nonodorized) pad. These data indicate that breast odors from lactating females are especially attractive to female infants who are unfamiliar with the stimulus woman and who have had no prior breast-feeding experience.     

Retention of conditioned autonomic and behavioral responses in preweanling rats: Forgetting and reinstatement

Preweanling rats, 16 days of age, responded to an olfactory conditioned stimulus (CS) paired with a shock unconditioned stimulus (US) with increases in heart rate and behavioral activation. In two experiments this finding was replicated and, in addition, it was found that the form of these conditioned responses (CRs) changed after a retention interval. When tested 24 h after CS-US pairings, the subjects displayed a decrease in heart rate accompanied by CS-elicited freezing. Giving two unsignaled shocks prior to the delayed test effectively reinstated the tachycardia and behavioral arousal CRs. The results are discussed in terms of contextual influences on the form of the CR and how changes in the magnitude of context fear may alter responding to an olfactory CS.     

大千世界

电灯泡的发明者托马斯·爱迪生是怕黑的。在1796年之前,美国有一个州叫富兰克林。它就是我们今天所熟知的田纳西州。被鳄鱼咬住时．想要逃脱的话,用拇指戳它的跟球——他就会立即松口。世界上三分之二的茄子生长在新泽西州。