中国虫草Cordycepssinensis的研究Ⅰ．名称和寄主的订正

结合对中国轮枝孢新种Ｖｅｒｔｉｃｉｌｉｕｍｓｉｎｅｎｓｉｓｓｐｎｏｖ的研究，分析评述了中国虫草Ｃｏｒｄｙｃｅｐｓｓｉｎｅｎｓｉｓ在名称、寄主、菌种和生境等诸方面的问题和研究结果，探讨了中国虫草的生物多样性问题．本文订正“中国虫草”为Ｃｓｉｎｅｎｓｉｓ的正式汉语学名，并在有效发表的４属３８种寄主昆虫中，初步确证其中的２属３１种为迄今涉及中国虫草的寄主昆虫     

冬虫夏草的药理作用研究及临床应用

冬虫夏草ＣｏｒｄｙｃｅｐｓｓｉｎｅｎｓｉｓＳａｃｃ(简称虫草 )是一种名贵强壮滋补中药。为麦角菌科植物冬虫夏草的子座及其寄主蝙蝠蛾科昆虫草蝙蝠蛾的幼虫尸体的复合体[1] 。由于天然虫草生长于高山地带 ,受气温、地理条件的限制 ,来源困难[2 ] 。为解决药源不足 ,现国内已经研究开发了多种人工培养虫草菌丝制剂。研究表明 ,虫草菌丝与天然虫草有相似的化学成分、药理作用和临床效果[3 ] 。本文就近年来对天然虫草及人工培养虫草菌的研究进展加以综述。1　虫草的化学成分1947年汤腾汉初次报道虫草含粗蛋白、脂肪、粗纤维、碳水化物、灰…     

蛹虫草栽培的关键因素及发展趋势

通过对蛹虫草栽培研究现状以及栽培面临的主要问题的分析,探究了蛹虫草栽培中菌种选育、复壮、培养基成分、栽培条件等关键因素,并展望了蛹虫草栽培的发展趋势.     

趣说冬虫夏草

“冬天是虫，夏天是草，冬虫夏草是个宝。”这说的就是一种名贵的药材——冬虫夏草。冬虫夏草简称虫草。关于虫草的生长，人们对其感到很神秘，前人曾有诗云：“冬虫夏草名符实，变化生成一气通。一物竞能兼动植，世间物理信难穷。”其实，虫草是一种昆虫与真菌的结合体，是冬季真菌寄生于虫草蛾幼虫体内，到了夏季发育而成。     

植物保护学--农业危害的"防火墙"

植物保护工作的任务是防治病虫草鼠的危害,确保农业生产的高产和稳产。指导植物保护工作的科学是植物保护学,它是研究植物病虫草鼠害的发生规律和防治理论与技术的科学。人类与植物病虫鼠害害作斗争历史悠久。从古代到现代,农业病虫草鼠害时有发生,给广大劳动人民带来一次又一次巨大的灾难。早在2000多年前,我们的祖先就开始进行植物病虫草鼠害的     

粉被虫草提取物抗癌作用初步研究

研究粉被虫草乙酸乙酯提取物和水提取物的体外抗肿瘤作用．人工发酵培养粉被虫草茵丝体,采用MTT和SRB法观察粉被虫草乙酸乙酯提取物、水提取物对人肝癌细胞株BEL-7402、人结肠癌细胞株COL0205的抑制作用．结果表明：粉被虫草水提取物对人结肠癌细胞COL0205抑制作用不显著,粉被虫草乙酸乙酯提取物对BEL-7402细胞抑制作用不显著．     

磁处理对蛹虫草菌丝生长量的影响

为了明确磁处理对蛹虫草菌丝生长量的影响,为磁处理在蛹虫草菌丝生产中的有效应用提供理论依据和参数.通过设置不同磁感应强度与不同磁处理时间的组合条件对蛹虫草菌丝进行磁处理,并采用菌丝重量法研究磁处理对菌丝生长量的生物学效应.结果表明,不同磁处理条件对蛹虫草菌丝生长量的生物学效应不同.产生正生物学效应的最佳磁处理条件为1.25 T/10 min.     

青海省果洛州冬虫夏草贸易初探

青海省果洛藏族自治州是我国冬虫夏草的主要产地,虫草贸易增加了当地人民的经济收入,改变了牧民的生活面貌。但是在兴盛的虫草贸易背后,也隐藏着许多问题。文章通过研究果洛州的虫草贸易现状,指出其中的几点问题,并提出对策,旨在促进果洛州虫草贸易健康有序地发展,提高当地人民的生活水平。     

人工虫草菌丝多糖含量测定

采用苯酚-硫酸比色法在491nm处优化人工虫草茼丝中多糖含量的测定条件，研究了不同提取条件对其含量的影响．经实验确定测定多糖的最优条件为：在40℃下，用苯酚-硫酸作显色剂，与待测液反应15min．并采用正交实验对人工虫草菌丝粉中的多糖提取条件进行优化．     

学好植物保护科学,当好植物医生

植物保护工作的任务是防治病虫草鼠的危害,确保农业生产高产和稳产。植物保护学是研究植物病虫草鼠害的发生规律和防治理论与技术的科学。     

Girls and computer science: experiences,perceptions, and career aspirations

The purpose of this mixed methods study was to examine ways to promote computer science (CS) among girls by exploring young women’s experiences and perceptions of CS as well as investigating factors affecting their career aspirations. American girls aged 10–16 participated in focus group interviews as well as pre-, post-, and follow-up surveys while attending a CS camp. The analysis of data revealed that although the participants were generally positive about the CS field, they had very limited knowledge of and experience with CS, leading to little aspiration to become computer scientists. The findings also indicated that girls’ affinity for and confidence in CS were critical factors affecting their motivation for pursuing a CS-related career. The study demonstrated that participation in the CS camp motivated a small number of participants to be interested in majoring in CS, but the activity time was too short to make a significant impact. Based on the findings, we suggest that providing CS programming experiences in K-12 classrooms is important in order to boost girls’ confidence and interest in CS.     

Conditioned aversion is promoted by memory of CS−

Five experiments tested the effects of experience with a white compartment not paired with footshock (CS?) on conditioning of an aversion to a black compartment paired with footshock. As previously found with odors as CSs, a single pairing of the CS+ with footshock yielded significant conditioning only if the animal was also exposed to CS?, with greater conditioning when the CS? exposure preceded the CS+ than when the CS+ preceded the CS?. If, however, the CS? preceded CS+ by a 24-h interval, it was ineffective and no CS+ conditioning occurred. For adult rats, the effectiveness of the CS?/CS+ “integration” progressively decreased with increasing length of the interval separating their occurrence, although it was still significant (i.e., some CS+ conditioning occurred) with a 12-h CS? to CS+ delay. For preweanlings (16 days postnatal), no conditioning to CS+ occurred if the interval between CS? and CS+ was 1 h or longer, although significant conditioning to CS+ did occur with a CS? to CS+ interval as long as 40 min. It was as if active memory for the CS? at the time of CS+ exposure was necessary for CS+ conditioning, and forgetting of the CS? memory proceeded more rapidly for preweanling than for adult rats. Collectively, these experiments extend results previously indicating that (1) the CS+ contiguous to the US may or may not be “selected” for conditioning, depending on the rat’s exposure to, or memory for, a CS?, and (2) this stimulus selection might differ for immature and mature rats.     

Temporal encoding in trace conditioning

Conditioned lick suppression in rats was used to explore the role of timing in trace conditioning. In Experiment 1, two groups of rats were exposed to pairings of a CS (CS1) with a US, under conditions in which the interstimulus interval (ISI) that separated CS1 offset and US onset was either 0 or 5 sec. Two additional groups were also exposed to the same CS1→US pairings with either a 0 or a 5-sec ISI, and then received “backward” second-order conditioning in which CS1 was immediately followed by a novel CS2 (i.e., CS1→CS2). A trace conditioning deficit was observed in that the CS1 conditioned with the 5-sec gap supported less excitatory responding than the CS1 conditioned with the 0-sec gap. However, CS2 elicited more conditioned responding in the group trained with the 5-sec CS1-US gap than in the group trained with the 0-sec CS1-US gap. Thus, the CS1-US interval had inverse effects on first- and second-order conditioned responding. Experiment 2 was conducted as a sensory preconditioning analogue to Experiment 1. In Experiment 2, rats received the CS1?CS2 pairings prior to the CS1→US pairings (in which CS1 was again conditioned with either a 0 or a 5-sec ISI). Experiment 2 showed a dissociation between first- and second-order conditioned responding similar to that observed in Experiment 1. These outcomes are not compatible with the view that differences in responding to CSs conditioned with different ISIs are mediated exclusively by differences in associative value. The results are discussed in the framework of the temporal coding hypothesis, according to which temporal relationships between events are encoded in elementary associations.     

Order and duration of stimuli are important determinants of reactivation

Prior cuing treatments intended to alleviate the forgetting of a conditioned avexsion-to an odor were tested with 18-day-old rats. Previous experiments had shown that when such pups were conditioned with the use of a CS?/CS+ procedure, pretest presentation of the CS? or US, but not the CS+, alleviated the forgetting otherwise seen after a 3-h retention interval. In Experiment 1, it was determined that the forgetting was not alleviated if the GS? was either preceded or followed by presentation of the CS+, despite the fact that the CS?/CS+ ordering mimicked that of original conditioning. Experiment 2 was an examination of the balance of extinction and reactivation effects caused by presenting the CS+ for varying durations following the 3-h retention interval. The forgetting over this interval was alleviated if the CS+ was presented for 5 or 15 sec, but not 30 sec. With an increase in duration of exposure from 15 to 30 sec, the consequences of the CS+ as a prior cuing treatment apparently shifted from reactivation to extinction. Experiment 3 was a test of the interaction between the consequences of different lengths of CS+ exposure and the effectiveness of adding CS? to the CS+ as a reactivation treatment. The varied effectiveness of reactivation treatments is discussed interms of a change in stimulus conditions from training to reactivation.     

Women planning to major in computer science: Who are they and what makes them unique?

Despite the current growing popularity of the computer science (CS) major, women remain sorely underrepresented in the field, continuing to earn only 18% of bachelor’s degrees. Understanding women’s low rates of participation in CS is important given that the demand for individuals with CS training has grown sharply in recent years. Attracting and retaining more women to high-paying fields like CS may also help narrow the gender pay gap. Further, it is important that women participate in developing new technology so that technology advances serve the needs of both women and men. This paper explores the background characteristics, career aspirations, and self-perceptions of 1636 female first-year college students in the United States who intend to major in CS and compares them with 4402 male CS aspirants as well as with 26,642 women planning to major in other STEM sub-fields. The findings reveal a unique profile of women who pursue the CS major and notes many significant differences between men and women in CS and between women in CS and those in other STEM fields. For instance, women in CS tend to earn lower high school grades than women in other STEM fields, but earn higher SAT verbal scores. They also rate themselves higher than men in CS and women in other STEM fields on measures of their artistic ability, but rate themselves lower on other self-ratings, including academic and leadership ability. Further, women in CS are more likely to be undecided in their career plans than men in CS and women in other STEM fields. Understanding the unique characteristics of women in CS will help inform policies and recruitment programs designed to address the gender gap in computing.     

Second-order conditioning of the rabbit’s nictitating membrane response as a function of the CS2-CS1 and CS1-US intervals

Three experiments investigated conditioning of the rabbit’s nictitating membrane response (NMR) in a second-order conditioning procedure which intermixed first-order trials (CS1-US) and second-order trials (CS2-CS1) from the outset of training. Experiment 1 provided a controlled demonstration that substantial levels of second-order conditioning can be obtained with the NMR preparation. Experiment 2 showed that the level of CR acquisition to CS2 was an inverse function of the CS2-CS1 interval over the values of 400, 800, and 2,400 msec. Experiment 3 found that CR acquisition to CS2 and CS1 in second-order conditioning varied in a parallel fashion across CS1-US intervals. Similarly, Experiment 3A found that the level of CR acquisition to the two components of a serial compound (CSA-CSB-US) varied in a parallel fashion as a function of the CSB-US interval. The results of the CS2-CS1 and CS1-US interval manipulations were all predictable from the known CS-US interval effects in NMR conditioning with a single CS. The present results are discussed with regard to their implications for accounts of serial compound conditioning and second-order conditioning.     

Effects of expected vs. unexpected proximal US preexposure on taste-aversion learning

Animals were first conditioned to expect lithium treatment following exposure to one taste solution (the CS+) and to expect no drug treatment following exposure to another flavor (the CS?). All subjects then received a saccharin taste-aversion conditioning trial. In Experiment 1, this conditioning trial was preceded 0, 1, 2, 4, or 6 h earlier by exposure to the CS+ flavor for independent groups. The CS+ exposure attenuated saccharin aversion learning if it occurred immediately before the saccharin conditioning trial but not if it occurred 1 h or more before conditioning. In Experiment 2, the saccharin conditioning trial was preceded 3 or 4.5 h earlier by a lithium injection. This proximal US preexposure injection was either unannounced (Li) or preceded by exposure to the CS+ (CS+Li) or the CS? (CS?Li) stimuli. The US preexposure attenuated saccharin aversion learning in all cases. However, the interference effect was less when the preexposure injection was expected (CS+Li) than when it was unexpected (CS?Li). This outcome could not be explained in terms of direct effects of the CS+ and CS? stimuli on the saccharin conditioning trial, and shows that the proximal US preexposure effect is a function of not only the drug dosage and preexposure interval, but also the anticipation of the drug pretreatment.     

语码转换的社会属性及其语用功能

语码转换是一种有趣而又独特的社会语言现象。目前,有关语码转换的研究主要集中在两个方面：1.对语码转换概念的探索以及对这一语言现象的历时性研究;2.大量的关于语码转换的语用及句法结构特征的个案研究。本文探讨了语码转换的社会属性及其语用功能。同时,鉴于以往研究中人们对语码转换这一概念缺乏统一的认识,本文也试图为语码转换提出一个工作定义。     

Two components of responding in Pavlovian lick suppression

The present research examined the temporal distribution of responding in a lick suppression paradigm. In Experiment 1, rats were trained with either a 30- or a 120-s conditioned stimulus (CS), which was followed either by a footshock (unconditioned stimulus [US]) or nothing. Licking during the CS was suppressed only in the former condition. Suppression was more pronounced early in the CS. In Experiment 2, rats were exposed to two 30-s or two 120-s CSs, with delivery of the shock being contingent on CS1 for half of the animals and on CS2 for the other half. For both the paired and the unpaired conditions, suppression at the beginning of CS1 was observed for all the groups. By discounting the possibility of generalization between CS1 and CS2, it appears that this initial suppression was not a conditioned response to the CS, but an unconditioned one due to mere exposure to the shock US.     

The role of temporal variables in inhibition produced through extinction

In two experiments with rats as subjects, the temporal characteristics of inhibition produced through extinction were investigated. Each experiment established two independent signals for unconditioned stimulus presentation, one trace and one delay. Following initial training, either the trace or the delay conditioned stimulus (CS) was massively extinguished. In Experiment 1, a summation test established that an extinguished delay CS (but not a neutral CS) passed a summation test with a delay, but not with a trace, transfer excitor, and an extinguished trace CS (but not a neutral CS) passed a summation test with a trace, but not with a delay, transfer excitor. In Experiment 2, a retardation test showed retarded behavioral control by an extinguished delay CS when the CS was retrained as a delay CS, but not as a trace CS, and by an extinguished trace CS when the CS was retrained as a trace CS, but not as a delay CS. The results are discussed in terms of contemporary theories of extinction.