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71.
The development of new communication technologies and their applications has opened a broad spectrum of options to promote learning, of which a significant one is CMC – Computer-Mediated Communication. Yet, students use this medium to a relatively small extent. Our premise is that the use of these technologies depends on the level of skills and expertise of the individuals using them. The purpose of this study is to determine whether taking a Computer Literacy and Applications course (CLA) before taking CMC courses has an impact on students' participation in CMC courses and on the effective use of various CMC tools. The sample consisted of 153 students enrolled in CMC courses in the Social Sciences in the Spring 2001/2 and Fall 2002/3 semesters. Participants were divided into two groups: 80 students who had taken CLA, and 73 students who had not. A questionnaire to assess the impact of CLA on participation in CMC courses was administered to the two groups. The results of the study indicate that participation in CMC courses is more intensive in the group that had taken CLA. Based on these findings, we recommend mandating a CLA course, like the one developed at the Open University of Israel (OUI), before taking CMC courses. 相似文献
72.
Effects of 3-pentanone and eight low molecular weight aliphatic alcohols and aldehydes identifed in the mixtures of volatiles released byAmaranthus palmeri S. Wats. (AMAPA) residues were determined on germination of onion, carrot, AMAPA, and tomato seeds. Three-day exposures to these volatiles significantly inhibited germination of these assay seeds, and the inhibition was dependent upon exposure time and concentration. Based on the degree of inhibition observed in both time- and concentration-dependent assays, the following activity series was obtained: 2-heptanol > 3-methyl-1-butanol, 1-hexanol > hexanal, 1-pentanol, 3-pentanone, acetaldehyde > ethanol, 2-methyl-1-propanol. The activities of this group of compounds with that of 2-heptanone appear to be additive and related to test compound volatility and hydrophilicity. 2-Heptanol and 2-heptanone also significantly inhibited the germination of other species, including shepherdspurse, soybean, lettuce, alfalfa, common purslane, oats, and lovegrass.Name of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned. 相似文献
73.
Dynamic control of polymorphic transformation in triglycerides by surfactants: The button syndrome 总被引:2,自引:2,他引:0
Judith Schlichter Aronhime Sara Sarig Nissim Garti 《Journal of the American Oil Chemists' Society》1988,65(7):1144-1150
The kinetics of polymorphic transformations in monoacid saturated triglycerides and the influence caused by the presence of
certain solid surfactants were investigated. Selected emulsifiers can be incorporated at the level of 10 wt% within the triglyceride,
without changing the crystal lattice; on the other hand, their presence affects the heat capacity of the triglyceride and
the NMR relaxation time T1. Following the polymorphic transformation both during aging and during heating in the DSC, it was observed that both the
mechanism and rate of transformation of the triglyceride strongly depend on the kinetic conditions and on its own chemical
structure. In conjunction with these results it also was observed that the effect of the emulsifier is strongly dependent
on the transformation conditions. The kinetic effect of the additive on the solid-solid transformation has been found to be
strictly associated with its hydrophilic moiety structure; a model of molecular incorporation has been proposed which describes
the arrangement of the surfactant molecules parallel to the triglyceride chains and formation of vacancies. The selectivity
of the additive concerning its effect of dynamic controller of polymorphic transformations has been explained by its capacity
to create hydrogen bonds with the neighboring triglycerides, which was called the “Button Syndrome.” The wide range of different
additives and triglycerides used supplied a better understanding of the factors which determine the polymorphic and crystallization
behavior in triglycerides. 相似文献
74.
Do parents have any important long-term effects on the development of their child's personality? This article examines the evidence and concludes that the answer is no. A new theory of development is proposed: that socialization is context-specific and that outside-the-home socialization takes place in the peer groups of childhood and adolescence. Intra- and intergroup processes, not dyadic relationships, are responsible for the transmission of culture and for environmental modification of children's personality characteristics. The universality of children's groups explains why development is not derailed by the wide variations in parental behavior found within and between societies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
75.
Habit and intention in everyday life: The multiple processes by which past behavior predicts future behavior. 总被引:8,自引:0,他引:8
Past behavior guides future responses through 2 processes. Well-practiced behaviors in constant contexts recur because the processing that initiates and controls their performance becomes automatic. Frequency of past behavior then reflects habit strength and has a direct effect on future performance. Alternately, when behaviors are not well learned or when they are performed in unstable or difficult contexts, conscious decision making is likely to be necessary to initiate and carry out the behavior. Under these conditions, past behavior (along with attitudes and subjective norms) may contribute to intentions, and behavior is guided by intentions. These relations between past behavior and future behavior are substantiated in a meta-analytic synthesis of prior research on behavior prediction and in a primary research investigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
Women's work roles have changed enormously. This article describes the long-term and short-term changes in women's paid employment. It also introduces a set of Public Forum articles that discuss the consequences of these changes for women's health and for their families and delineate the government's responses to women's changing work roles. The impetus for this Public Forum section came from a workshop conducted under the auspices of the John D. and Catherine T. MacArthur Foundation Network on the Determinants and Consequences of Health-Promoting and Health-Damaging Behaviors. Therefore, the article also discusses the mission of the Network and why multidisciplinary, collaborative research on the effects of women's employment is vital. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
77.
Reports an abrupt downturn in the market for psychologists as shown in a series of spring placement services studies. The number of positions advertised in the base-line year of 1969 was over twice the number advertised in 1971. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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80.
SEM and X-ray microprobe analysis were combined with clean lab technology atomic absorption spectroscopy to observe the deposition of aerosols on undisturbed pine needle surfaces, to obtain physical and chemical information from the observed particles and to chemically remove these particles for analysis. Comparisons were made among sites with traffic densities of 100, 1000, 10000 cars per day. Correlations were made with periods of heavy rainfall. The results show that the particle size distribution, shape and surface chemistry are possibly characteristic of automotive exhausts, that both the chemical washing procedure and rainfall efficiently remove most particles from the surface, including those bearing lead, and that the rate of deposition is constant between rainfalls and partly a function of traffic density. Deposition rates of 0.3 ng Pb cm?2 day?1 were observed at 100 cars per day, 2–3 ng Pb cm?2 day?1 for 1000 and 10000 cars per day. 相似文献