Microbial control of diamondback moth, Plutella xylostella L.(Lepidoptera: Yponomeutidae) using bacteria (Xenorhabdus nematophila) and its metabolites from the entomopathogenic nematode Steinernema carpocapsae     

MAHAR Ali Nawaz  MUNIR Muhammad  ELAWAD Sami  GOWEN Simon Richard  HAGUE Nigel Graham Meckenzi 《Journal of Zhejiang University. Science. B》2004,(10)

Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X. nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.  相似文献   

Learning strategies in an 'ideal' computer-based learning environment     

Nigel Ford  Rosalind Ford 《British journal of educational technology : journal of the Council for Educational Technology》1992,23(3):195-211

An experiment was conducted with 30 postgraduate students to discover how they might go about learning from an 'ideal' computer-based environment. A system was created which preserved the appearance of a computer-based interaction, yet which freed itself from the constraints of current technology. The students, although not aware of this at the time, were in fact interacting with two human experts, backed up with appropriate documentation and computer files, via a computer screen. The results suggest a number of different learning strategies linked to relatively successful and less successful learning. Implications for the design of computer-based learning materials are discussed.  相似文献   

Avoidance,classical, and pseudoconditioning as a function of species-specific defense reactions in high- and low-avoider rat strains     

Nigel W. Bond 《Learning & behavior》1984,12(3):323-331

Rats of the Australian High Avoider (AHA) and Australian Low Avoider (ALA) strains and their reciprocal crosses were exposed to 50 trials of one of three shuttlebox procedures. The avoidance group received pairings of a tone and shock. If the animals shuttled during the tone, they avoided the shock. If they waited until the shock came on, they could then escape it. The classical group received pairings of the tone and a brief inescapable shock. If they shuttled during the tone, the tone ceased and they immediately received the shock. If they did not shuttle, they received the brief shock at the termination of the tone. The pseudoconditioning group received the tone and the shock explicitly unpaired. If they shuttled during either the tone or the shock, the stimulus was terminated. There was no acquisition of anticipatory responding under the pseudoconditioning procedure. All groups evidenced an increase in anticipatory responding over trials under the classical procedure. The AHAs acquired the response faster and reached a higher asymptote than did the ALAs. Performance of the two reciprocal crosses fell in between. A similar pattern was observed under the avoidance procedure, albeit at slightly higher response levels. Subsequent studies established that the AHAs acquired a one-way avoidance response quickly, but were impaired on a passive avoidance task, whereas the reverse was the case for the ALAs. The reciprocal crosses were proficient at both tasks. These results suggest that shuttlebox avoidance is largely accounted for by classical conditioning of the predominant defensive response. When that response is compatible with performance on the task, acquisition is rapid (AHAs), and when it is not, acquisition is slow (ALAs).  相似文献   

天然白桦种苗光合作用日进程   总被引：6，自引：0，他引：6  

王爱民  刘志学  祖元刚 《上海大学学报(英文版)》2000,(Z1)

本研究采用最先进的光合作用测定系统ＬＩ－６４００测定多功能树种白桦种苗的光合作用．天然白桦种苗光合速率日进程表现为单峰曲线,在下午１４： ００时达到最高峰（１０．５３μｍｏｌＣＯ２ｍ－２ｓ－１）,．其光合作用不存在“午休现象”．在１４：００时,白桦的气孔限制值（０.３１７２）和水分饱和亏缺（２．４６ｋＰａ）分别达到最大值,此时其水分利用效率较高,在中午１２：００时水分利用率达到最大值（２．９７ ｕｍｏｌＣＯ２ｍ－２ｓ－１ｍｍＨ２Ｏｍ－２ｓ－１）．在早上８：００,白桦获得一天中最大的表观量子效率;其蒸腾速率在下午１４： ００时最大（４．８２ｍｍＨ２Ｏｍ－２ｓ－１）．在光合速率的日进程中,白桦高光合速率值持续至少 ４个小时．这使得白桦的光合作用量得以有效累积,进而为其生长创造了有利条件．  相似文献   

Talking to children about science is harder than we think: characteristics and metacognitive judgments of explanations provided to children and adults     

Haley A. Vlach  Nigel Noll 《Metacognition and Learning》2016,11(3):317-338

Adults modify the way they speak to children to support children’s learning across several domains. However, no previous research has studied whether adults change their language when explaining science to children. The current study examined if and how adults change the manner in which they talk about science when providing explanations to children vs. providing explanations to other adults. Participants (N = 81) were video recorded while explaining basic science concepts to children and adults. Recordings were later analyzed to determine if and how participants changed the quality and content of their explanations. The results confirmed that adults did change their explanations when talking to children about science by providing more potentially beneficial, but also disadvantageous, information. Participants perceived that they provided more accurate explanations to children, but appeared to be making metacognitive judgments largely based upon the changes made that could be beneficial to learning. Taken together, this work suggests that science may be a domain in which adults are not well equipped to modify and monitor their language to children.  相似文献   

BOOK REVIEWS     

Dr Mikel Burley  Peter Doble  Revd Janina Ainsworth  Nigel Fancourt  Joyce Miller  Dr Julian Stern 《British Journal of Religious Education》2007,29(2):189-209

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Temporal patterning of competitive emotions: A critical review     

Ester Cerin  Attila Szabo  Nigel Hunt  Clive Williams 《Journal of sports sciences》2013,31(8):605-626

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The extent and causes of home advantage: Some recent insights     

Alan Nevill  Nigel Balmer  Sandy Wolfson 《Journal of sports sciences》2013,31(4):335-336

The effect of strategy instruction on response time in a sequential keypressing task was compared during acquisition and retention. Specifically, this study determined the influence of: (1) an awareness strategy, (2) a non‐awareness strategy, (3) a Five‐Step Approach strategy and (4) a control condition. Sixty‐four subjects completed 250 trials of nine sequential keypresses, and 50 trials of a dual task (keypresses and verbal report). Faster response times were found for the Five‐Step Approach and non‐awareness strategies during both acquisition and retention. Introducing beginners to strategies that are used by highly skilled performers facilitated response times.  相似文献   

Sports nutritionists’ perspectives on enablers and barriers to nutritional adherence in high performance sport: A qualitative analysis informed by the COM-B model and theoretical domains framework     

Meghan RN Bentley  Nigel Mitchell  Louise Sutton 《Journal of sports sciences》2013,31(18):2075-2085

ABSTRACT

Athlete adherence to nutritional guidance is critical for optimal health and performance, yet little is known about the barriers and enablers to athletes’ dietary behaviours within high-performance sport. To advance understanding, we applied a theoretical lens derived from the Capability, Opportunity, Motivation – Behaviour (COM-B) model and the Theoretical Domains Framework (TDF) to explore the qualitative accounts of sports nutritionists. Five focus groups comprising sports nutritionists working in Olympic and Paralympic sport (n = 14), professional sport (n = 6), or both (n = 6) were undertaken. Thematic analysis was conducted and the interpretations of the findings were guided by COM-B and the TDF. To achieve nutritional adherence, the behavioural analysis identified the need to intervene across all three COM-B components and at least five associated TDF domains (e.g., decision-making processes, reinforcement, social influences, behavioural regulation and environmental context and resource). For the first time, the findings illustrate the complex interplay of the training setting with the capabilities, opportunities, and motivation of the practitioners, athletes and coaches. By applying established behavioural science theories to sports nutrition, the foundations for the development of targeted and multifaceted behavioural interventions addressing athlete dietary adherence in high-performance sport have been laid.  相似文献   

Neighborhood Physical Activity Opportunity: A Multilevel Contextual Model     

Susan C. Duncan  Terry E. Duncan  Lisa A. Strycker  Nigel R. Chaumeton 《Research quarterly for exercise and sport》2013,84(4):457-463

Purpose: The aims of this study were to analyze the intensity of emotions (positive, negative, or ambiguous) produced when players took part in traditional games with a different social structure and to examine the explanations given by those participants for these emotional experiences. Method: Participants (N = 556) were recruited from 4 Spanish universities. After taking part in each of the games, they were asked to complete the Games and Emotions Questionnaire to indicate the intensity of their emotional experiences and to explain what, in their view, had led to the strongest emotion felt. Results: The application of a mixed-methods approach identified statistically significant differences in relation to 3 variables. These were (a) the type of emotion, (b) motor domain, and (c) type of result (win, loss, and noncompetitive). The intensity of positive emotions was higher in cooperative games and lower in individual games. Comments referring to negative emotions were more frequent as the social structure of games became more complex (minimal presence of individual games and predominance of cooperation-opposition games). Winning was associated with the highest intensity ratings of positive and ambiguous emotions, whereas being defeated produced the highest values for negative emotions. The intensity ratings for negative emotions were lower in noncompetitive games than in games where players lost. Conclusion: The results confirm that traditional games can play a key role in relation to the emotional facets of physical education.  相似文献