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Explanatory Mechanisms (explanatory + mechanism)
Selected AbstractsThe effect of state extraversion on four types of affectEUROPEAN JOURNAL OF PERSONALITY, Issue 1 2010J. Murray McNiel Abstract The primary purpose of this study was to determine the effect of state extraversion on different types of affect. Ninety six participants were instructed to be extraverted or introverted in a 10-minute dyadic discussion. State extraversion had a strong effect on positive affect and smaller (but still strong) effects on pleasant and activated affect, with these latter two effects almost equal in magnitude. This pattern of findings appears to increase confidence that the effect of state extraversion is genuine rather than the result of construct overlap, in that extraversion's effect on positive affect is not dominated by its effect on activated affect. No support for reward sensitivity as a potential explanatory mechanism was found. Copyright © 2009 John Wiley & Sons, Ltd. [source] Why forgiveness may protect against depression: Hopelessness as an explanatory mechanismPERSONALITY AND MENTAL HEALTH, Issue 2 2008Loren L. Toussaint This study examined associations between multiple dimensions of forgiveness with hopelessness and depression. Further, this study investigated the extent to which hopelessness mediated associations between forgiveness and depression. We used an adapted model and drew on beginning work showing associations between forgiveness, hope/hopelessness and depression. We predicted that forgiveness would be significantly inversely correlated with hopelessness and depression, and that hopelessness would mediate the associations between forgiveness and depression. We controlled for religiousness/spirituality and demographic factors in our analyses, and used data from a nationally representative probability sample of 1,423 adults, ages 18 years and older. Results showed that forgiveness of oneself and others was negatively correlated, and seeking forgiveness was positively correlated with depression. Forgiveness of oneself and others was associated with hopelessness. Mediation analyses revealed that hopelessness partially mediated the associations between forgiveness of oneself and others with depression. The present findings provide support for theoretical and conceptual work connecting forgiveness, hope and mental health, and add to a scant empirical literature on these topics. Copyright © 2008 John Wiley & Sons, Ltd. [source] THE RELATIONS OF DAILY COUNTERPRODUCTIVE WORKPLACE BEHAVIOR WITH EMOTIONS, SITUATIONAL ANTECEDENTS, AND PERSONALITY MODERATORS: A DIARY STUDY IN HONG KONGPERSONNEL PSYCHOLOGY, Issue 2 2009JIXIA YANG In this diary study conducted in Hong Kong, we examined a theoretical model in which negative emotions serve as an explanatory mechanism through which daily stressors impact daily counterproductive work behavior (CWB). We further theorized that personality variables (negative affectivity, Conscientiousness, and Agreeableness) would exert cross-level effects on the within-person relationships. Hierarchical linear modeling results based on a sample of 231 individuals and 5,583 observations across 25 days provide partial support for the mediating role of negative emotions in the within-person stressor,CWB relationships. Specifically, we found that negative emotions (a) partially mediated the within-person relation of perceived ambiguity with CWB directed at the organization, (b) fully mediated the relation of supervisor interpersonal injustice with CWB directed at individuals, and (c) fully mediated the relation of customer interpersonal injustice with CWB directed at the organization. High levels of trait negative affectivity were found to strengthen the within-person relation between daily supervisor interpersonal injustice and daily negative emotions. As expected, high levels of trait Conscientiousness and Agreeableness were found to weaken the within-person relations of daily negative emotions with daily CWB directed at the organization and individuals. [source] Developing a learning progression for scientific modeling: Making scientific modeling accessible and meaningful for learnersJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 6 2009Christina V. Schwarz Abstract Modeling is a core practice in science and a central part of scientific literacy. We present theoretical and empirical motivation for a learning progression for scientific modeling that aims to make the practice accessible and meaningful for learners. We define scientific modeling as including the elements of the practice (constructing, using, evaluating, and revising scientific models) and the metaknowledge that guides and motivates the practice (e.g., understanding the nature and purpose of models). Our learning progression for scientific modeling includes two dimensions that combine metaknowledge and elements of practice,scientific models as tools for predicting and explaining, and models change as understanding improves. We describe levels of progress along these two dimensions of our progression and illustrate them with classroom examples from 5th and 6th graders engaged in modeling. Our illustrations indicate that both groups of learners productively engaged in constructing and revising increasingly accurate models that included powerful explanatory mechanisms, and applied these models to make predictions for closely related phenomena. Furthermore, we show how students engaged in modeling practices move along levels of this progression. In particular, students moved from illustrative to explanatory models, and developed increasingly sophisticated views of the explanatory nature of models, shifting from models as correct or incorrect to models as encompassing explanations for multiple aspects of a target phenomenon. They also developed more nuanced reasons to revise models. Finally, we present challenges for learners in modeling practices,such as understanding how constructing a model can aid their own sensemaking, and seeing model building as a way to generate new knowledge rather than represent what they have already learned. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 632,654, 2009 [source] ON SOCIAL NETWORK ANALYSIS IN A SUPPLY CHAIN CONTEXT,JOURNAL OF SUPPLY CHAIN MANAGEMENT, Issue 2 2009STEPHEN P. BORGATTI The network perspective is rapidly becoming a lingua franca across virtually all of the sciences from anthropology to physics. In this paper, we provide supply chain researchers with an overview of social network analysis, covering both specific concepts (such as structural holes or betweenness centrality) and the generic explanatory mechanisms that network theorists often invoke to relate network variables to outcomes of interest. One reason for discussing mechanisms is to facilitate appropriate translation and context-specific modification of concepts rather than blind copying. We have also taken care to apply network concepts to both "hard" types of ties (e.g., materials and money flows) and "soft" types of ties (e.g., friendships and sharing-of-information), as both are crucial (and mutually embedded) in the supply chain context. Another aim of the review is to point to areas in other fields that we think are particularly suitable for supply chain management (SCM) to draw network concepts from, such as sociology, ecology, input,output research and even the study of romantic networks. We believe the portability of many network concepts provides a potential for unifying many fields, and a consequence of this for SCM may be to decrease the distance between SCM and other branches of management science. [source] Food-web assembly during a classic biogeographic study: species'"trophic breadth" corresponds to colonization orderOIKOS, Issue 5 2008Denise A. Piechnik Ecologists have found many patterns in food-web structure. Some, like the constant connectance hypothesis, lack definitive explanatory mechanisms. In response, we investigated whether community assembly mechanisms could explain why trophic complexity consistently scales with species richness among ecosystems. We analyzed how food-web structure developed during the community assembly recorded in Simberloff and Wilson's classic biogeography experiment. Using their arthropod surveys, we constructed six time series of food-webs from pre- and post-defaunation censuses of six experimental islands, and synthesized trophic information for 250 species from the literature and expert sources. We found that the fraction of specialist species increased and the fraction of generalists decreased during food-web assembly. Directed connectance initially declined over time, despite an increase in species richness, but eventually leveled off as predicted by the constant connectance hypothesis of diversity-complexity scaling. The initial decline was explained by later colonization by trophic specialists, probably due to limited resource availability during early colonization. Late-colonizing super-generalists maintained constant connectance at later dates. This relationship between colonization success and trophic breadth helps explain food-web patterns and corroborates assertions that community assembly is systematically influenced by species' trophic breadths. [source] Does disturbance, competition or resource limitation underlie Hieracium lepidulum invasion in New Zealand?AUSTRAL ECOLOGY, Issue 3 2010Mechanisms of establishment, functional differentiation among invasive, native species, persistence Abstract The processes underlying plant invasions have been the subject of much ecological research. Understanding mechanisms of plant invasions are difficult to elucidate from observations, yet are crucial for ecological management of invasions. Hieracium lepidulum, an asteraceous invader in New Zealand, is a species for which several explanatory mechanisms can be raised. Alternative mechanisms, including competitive dominance, disturbance of resident vegetation allowing competitive release or nutrient resource limitation reducing competition with the invader are raised to explain invasion. We tested these hypotheses in two field experiments which manipulated competitive, disturbance and nutrient environments in pre-invasion and post-invasion vegetation. H. lepidulum and resident responses to environmental treatments were measured to allow interpretation of underlying mechanisms of establishment and persistence. We found that H. lepidulum differed in functional response profile from native species. We also found that other exotic invaders at the sites were functionally different to H. lepidulum in their responses. These data support the hypothesis that different invaders use different invasion mechanisms from one another. These data also suggest that functional differentiation between invaders and native resident vegetation may be an important contributing factor allowing invasion. H. lepidulum appeared to have little direct competitive effect on post-invasion vegetation, suggesting that competition was not a dominant mechanism maintaining its persistence. There was weak support for disturbance allowing initial establishment of H. lepidulum in pre-invasion vegetation, but disturbance did not lead to invader dominance. Strong support for nutrient limitation of resident species was provided by the rapid competitive responses with added nutrients despite presence of H. lepidulum. Rapid competitive suppression of H. lepidulum once nutrient limitation was alleviated suggests that nutrient limitation may be an important process allowing the invader to dominate. Possible roles of historical site degradation and/or invader-induced soil chemical/microbial changes in nutrient availability are discussed. 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