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Two experiments were performed having in common the use of sucrose concentration and volume as amount of reinforcement variables, and in situations permitting contrast between concentrations. The following conclusions are reached:

1. It is important to distinguish between the case in which separate subjects are exposed to different concentrations or volumes, and the case in which the same subjects receive different concentrations and volumes.

2. A distinction must be drawn between reinforcement contingencies in which force of response is or is not systematically related to concentration received. In nonforce contingent situations, emitted force is inversely related to concentration, when the same subjects are exposed to the different concentrations. In contingent situations, the relationship tends to be direct.

3. Rate and force of response vary inversely with nonforce contingent volume of sucrose reinforcement, when the same subjects are exposed to the different volumes.

4. Regardless of concentration and volume used, and presumably because of within-session satiation effects, there is a general tendency for rate to decline during nonforce contingent sessions.  相似文献   
104.
Past research has attempted to delineate personality differences between insomniacs and good sleepers but has failed to control for type of insomnia or severity of the disorder. The purpose of this study was to compare MMPI scores of mild and severe sleep onset insomniacs with a control group of noninsomniacs. Results demonstrated that sleep onset insomniacs, regardless of degree of severity, differed significantly from noninsomniacs; and that mild and severe insomniacs differed from each other on only one MMPI scale.  相似文献   
105.
We tested the effects of team strategic orientation on team member perceptions, work strategy and information search. In Experiment 1, 80 teams worked on a hidden profile decision-making task. A defensive team strategic orientation increased members’ perceptions of the problem’s scope, leading to a more process-focused work strategy and broader information search compared to an offensive team strategic orientation. When teams needed critical information from the environment, defensive teams outperformed offensive teams; offensive teams performed better when critical information resided within the team. In Experiment 2, these findings were replicated with 92 teams performing a different decision task. When making a second decision, half of the teams were led to change their strategic orientation; teams shifting from offense to defense altered their information search behavior more readily than did teams shifting in the opposite direction, suggesting an asymmetric adaptation effect.  相似文献   
106.
A familiar feature of our moral responsibility practices are pleas: considerations, such as “That was an accident”, or “I didn’t know what else to do”, that attempt to get agents accused of wrongdoing off the hook. But why do these pleas have the normative force they do in fact have? Why does physical constraint excuse one from responsibility, while forgetfulness or laziness does not? I begin by laying out R. Jay Wallace’s (Responsibility and the moral sentiments, 1994) theory of the normative force of excuses and exemptions. For each category of plea, Wallace offers a single governing moral principle that explains their normative force. The principle he identifies as governing excuses is the Principle of No Blameworthiness without Fault: an agent is blameworthy only if he has done something wrong. The principle he identifies as governing exemptions is the Principle of Reasonableness: an agent is morally accountable only if he is normatively competent. I argue that Wallace’s theory of exemptions is sound, but that his account of the normative force of excuses is problematic, in that it fails to explain the full range of excuses we offer in our practices, especially the excuses of addiction and extreme stress. I then develop a novel account of the normative force of excuses, which employs what I call the “Principle of Reasonable Opportunity,” that can explain the full range of excuses we offer and that is deeply unified with Wallace’s theory of the normative force of exemptions. An important implication of the theory I develop is that moral responsibility requires free will.  相似文献   
107.
In this study, we examine when creativity is positively or negatively related to firm performance. Building on the creation–implementation tension theorized in the literature and the attention capacity perspective, we argue that the relationship between creativity and firm performance is contingent on riskiness orientation, firm size, and realized absorptive capacity. Data were collected from 761 core knowledge employees, 148 CEOs, and 148 HR executives from 148 high‐technology firms. The results indicated that core knowledge employee creativity was negatively related to firm performance when riskiness orientation was high. The relationship was positive when realized absorptive capacity was high. Finally, the relationship was more positive in small firms than in large firms. We discuss the implications of our findings for creativity research and managerial practices.  相似文献   
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Abstract

Chaki (1988) has recently proposed a model for diffusion-induced grain boundary migration (DIGM). In his Letter he concluded that the interface energy of a grain boundary and the free energy of mixing are responsible for DIGM and, from the equations he derived, it was claimed that they can explain many DIGM experimental results. However, on examining his model closely there appear to be some fundamental difficulties. The following are comments on his Letter:

(1) In Chaki's calculation of ΔGs he assumed that, after interface 1 had moved a distance δx, the radius of curvature of this interface increased from R to R + δx, which gives a surface energy drop of 2γVm δx/R2. However from many DIGM observations (for example Balluffi and Cahn (1981)) the curvature of a migrating boundary is increased rather then decreased, that is, the surface free- energy term actually prevents a grain boundary from migrating rather than helping it!

(2) Chaki considered ΔGcryst during the migration of interface 2. It is also necessary to consider AGcrys, during the migration of interface 1, since within the migration distance δx the structure is changed from a crystalline structure to a grain boundary core structure. ΔGm should also be considered during the migration of interface 2 since the concentration of the area swept by interface 2 will not be the same as that of a grain boundary core.  相似文献   
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