Showing papers by "University of North Carolina at Charlotte published in 2004"

Target Article: "Posttraumatic Growth: Conceptual Foundations and Empirical Evidence".

Abstract: This article describes the concept of posttraumatic growth, its conceptual foundations, and supporting empirical evidence. Posttraumatic growth is the experience of positive change that occurs as a result of the struggle with highly challenging life crises. It is manifested in a variety of ways, including an increased appreciation for life in general, more meaningful interpersonal relationships, an increased sense of personal strength, changed priorities, and a richer existential and spiritual life. Although the term is new, the idea that great good can come from great suffering is ancient. We propose a model for understanding the process of posttraumatic growth in which individual characteristics, support and disclosure, and more centrally, significant cognitive processing involving cognitive structures threatened or nullified by the traumatic events, play an important role. It is also suggested that posttraumatic growth mutually interacts with life wisdom and the development of the life narrative, and t...

How to Solve It: Modern Heuristics

Abstract: I What Are the Ages of My Three Sons?.- 1 Why Are Some Problems Difficult to Solve?.- II How Important Is a Model?.- 2 Basic Concepts.- III What Are the Prices in 7-11?.- 3 Traditional Methods - Part 1.- IV What Are the Numbers?.- 4 Traditional Methods - Part 2.- V What's the Color of the Bear?.- 5 Escaping Local Optima.- VI How Good Is Your Intuition?.- 6 An Evolutionary Approach.- VII One of These Things Is Not Like the Others.- 7 Designing Evolutionary Algorithms.- VIII What Is the Shortest Way?.- 8 The Traveling Salesman Problem.- IX Who Owns the Zebra?.- 9 Constraint-Handling Techniques.- X Can You Tune to the Problem?.- 10 Tuning the Algorithm to the Problem.- XI Can You Mate in Two Moves?.- 11 Time-Varying Environments and Noise.- XII Day of the Week of January 1st.- 12 Neural Networks.- XIII What Was the Length of the Rope?.- 13 Fuzzy Systems.- XIV Everything Depends on Something Else.- 14 Coevolutionary Systems.- XV Who's Taller?.- 15 Multicriteria Decision-Making.- XVI Do You Like Simple Solutions?.- 16 Hybrid Systems.- 17 Summary.- Appendix A: Probability and Statistics.- A.1 Basic concepts of probability.- A.2 Random variables.- A.2.1 Discrete random variables.- A.2.2 Continuous random variables.- A.3 Descriptive statistics of random variables.- A.4 Limit theorems and inequalities.- A.5 Adding random variables.- A.6 Generating random numbers on a computer.- A.7 Estimation.- A.8 Statistical hypothesis testing.- A.9 Linear regression.- A.10 Summary.- Appendix B: Problems and Projects.- B.1 Trying some practical problems.- B.2 Reporting computational experiments with heuristic methods.- References.

Cognitive enhancers as adjuncts to psychotherapy: use of D-cycloserine in phobic individuals to facilitate extinction of fear.

Abstract: Background Traditional pharmacological approaches to treating psychiatric disorders focus on correcting presumed biochemical abnormalities. However, some disorders, particularly the anxiety-related disorders exemplified by specific phobia, have an emotional learning component to them that can be facilitated with psychotherapy. Objective To determine whether D-cycloserine (DCS), a partial agonist at theN-methyl-D-aspartate receptor that has previously been shown to improve extinction of fear in rodents, will also improve extinction of fear in human phobic patients undergoing behavioral exposure therapy. Design Randomized, double-blind, placebo-controlled trial examining DCS vs placebo treatment in combination with a precisely controlled exposure paradigm. Setting Participants were recruited from the general community to a research clinic. Participants Twenty-eight subjects with acrophobia diagnosed by the Structured Clinical Interview forDSM-IVwere enrolled. Interventions After we obtained pretreatment measures of fear, subjects were treated with 2 sessions of behavioral exposure therapy using virtual reality exposure to heights within a virtual glass elevator. Single doses of placebo or DCS were taken prior to each of the 2 sessions of virtual reality exposure therapy. Subjects, therapists, and assessors were blind to the treatment condition. Subjects returned at 1 week and 3 months posttreatment for measures to determine the presence and severity of acrophobia symptoms. Main Outcome Measures Included were measures of acrophobia within the virtual environment, measures of acrophobia in the real world, and general measures of overall improvement. An objective measure of fear, electrodermal skin fluctuation, was also included during the virtual exposure to heights. Symptoms were assessed by self-report and by independent assessors at approximately 1 week and 3 months posttreatment. Results Exposure therapy combined with DCS resulted in significantly larger reductions of acrophobia symptoms on all main outcome measures. Subjects receiving DCS had significantly more improvement compared with subjects receiving placebo within the virtual environment (1 week after treatment,P≤.001; 3 months later,P≤.05). Subjects receiving DCS also showed significantly greater decreases in posttreatment skin conductance fluctuations during the virtual exposure (P≤.05). Additionally, subjects receiving DCS had significantly greater improvement compared with subjects receiving placebo on general measures of real-world acrophobia symptoms (acrophobia avoidance [P≤.02], acrophobia anxiety [P≤.01], attitudes toward heights [P≤.04], clinical global improvement [P≤.01], and number of self-exposures to real-world heights [P≤.01]); the improvement was evident early in treatment and was maintained at 3 months. Conclusion These pilot data provide initial support for the use of acute dosing of DCS as an adjunct to exposure-based psychotherapy to accelerate the associative learning processes that contribute to correcting psychopathology.

The experienced "sense" of a virtual community: characteristics and processes

Abstract: E-commerce strategists advise companies to create virtual communities for their customers. But what does this involve? Research on face-to-face communities identifies the concept of "sense of community:" a characteristic of successful communities distinguished by members' helping behaviors and members' emotional attachment to the community and other members. Does a sense of virtual community exist in online settings, and what does it consist of? Answering these questions is key, if we are to provide guidance to businesses attempting to create virtual communities.The paper explores the concept of sense of virtual community in a newsgroup we call Multiple Sports Newsgroup (MSN). We first demonstrate that MSN does indeed have a sense of virtual community, but that the dimensions of the sense of community in MSN differ somewhat from those reported for physical communities. The nature of these differences is plausibly related to the differences between electronic and face-to-face communication. We next describe the behavioral processes that contribute to the sense of virtual community at MSN-exchanging support, creating identities and making identifications, and the production of trust. Again, these processes are similar to those found in non-virtual communities, but they are related to the challenges of electronic communication. Lastly, we consider the question of how sense of community may come about and discuss the implications for electronic business.

A Values Framework for Measuring the Impact of Workplace Spirituality on Organizational Performance

Abstract: Growing interest in workplace spirituality has led to the development of a new paradigm in organizational science Theoretical assumptions abound as to how workplace spirituality might enhance organizational performance, most postulating a significant positive impact Here, that body of research has been reviewed and analyzed, and a resultant values framework for workplace spirituality is introduced, providing the groundwork for empirical testing A discussion of the factors and assumptions involved for future research are outlined

Moderators of the relationships between coworkers' organizational citizenship behavior and fellow employees' attitudes.

Abstract: The authors developed and tested the prediction that the relationship hetween coworkers' organizational citizenship behaviors (OCBs) and fellow employees' attitudes depends on the supervisors' abusiveness. Results of a longitudinal study using data collected from 173 supervised employees at 2 points in time (separated by 7 months) suggested that coworkers' OCB was positively related to fellow employees' job satisfaction and affective commitment when abusive supervision was low. However, when abusive supervision was high, coworkers' OCB was negatively related to job satisfaction and was unrelated to organizational commitment. The results of a 2nd study were consistent with the idea that the attributions employees make for their coworkers' OCB explains the moderating effect of abusive supervision on the relationship between coworkers' OCB and job satisfaction.

The Role of Work Context in Work Motivation: A Public Sector Application of Goal and Social Cognitive Theories

Abstract: The present study represents a test of a conceptual model predicting how the organization’s work context might influence work motivation. Using the framework provided by goal and social cognitive theories, this model of work motivation assesses whether aspects of the organizational work context, such as greater goal conflict, procedural constraints, and goal ambiguity, may have a detrimental effect on work motivation through their influence on three important antecedents of work motivation: job goal specificity, job difficulty, and self-efficacy. Although the findings of a covariance (LISREL) analysis of state government employee survey data suggested a few minor modifications to this model, the results indicated that the theoretical framework can identify specific leverage points that can increase work motivation and, therefore, productivity in the public sector.

Neutralizing job stressors: political skill as an antidote to the dysfunctional consequences of role conflict

Abstract: We examined the neutralizing effects of political skill on relationships between perceived role conflict and strain. Strain was measured as psychological anxiety, somatic complaints, and physiologi...

Multicultural Issues in Autism

Abstract: The professional literature provides ample evidence that individuals with autism exhibit a myriad of unusual social, communication, and behavioral patterns of interactions that present challenges to their families and service providers. However, there is a dearth of quality works on multicultural issues regarding autistic spectrum disorders. In this article, we explore issues surrounding autism and multiculturalism, with the intent not to provide answers but to raise questions for further examination. We focus our discussions on two primary issues: autism within cultural groups and multicultural family adaptation based on the framework of pluralistic societies in which some cultural groups are a minority within the dominant culture. We found differences in prevalence rates across races for autism and little information regarding how multicultural families adapt to raising a child with autism. Further, students with multicultural backgrounds and autism are challenged on at least four dimensions: communication, social skills, behavioral repertoires, and culture. Future research in these areas is clearly warranted.

Parental Socialization and Community Context: A Longitudinal Analysis of the Structural Sources of Low Self-Control

Abstract: Several empirical studies have attempted to estimate the effect of low self-control on criminal and “analogous” behaviors. Most of these studies have shown that low self-control is an important feature of the cause(s) of crime. Although research is beginning to emerge that targets more specifically the “roots” of self-control via parental socialization (the most salient factor in the development of self-control according to Hirschi and Gottfredson), researchers have yet to explore the degree to which the structural characteristics of communities may influence patterns of parental socialization and, in turn, individual levels of self-control. To address this question, the authors employ longitudinal data from the National Longitudinal Survey of Youth (NLSY) to examine community-level influences on parental socialization and self-control. The results indicate (1) self-control was predicted both cross-sectionally and longitudinally by both parental socialization and adverse neighborhood conditions, (2) the t...

Integration and Modularity of Quantitative Trait Locus Effects on Geometric Shape in the Mouse Mandible

Abstract: The mouse mandible has long served as a model system for complex morphological structures. Here we use new methodology based on geometric morphometrics to test the hypothesis that the mandible consists of two main modules, the alveolar region and the ascending ramus, and that this modularity is reflected in the effects of quantitative trait loci (QTL). The shape of each mandible was analyzed by the positions of 16 morphological landmarks and these data were analyzed using Procrustes analysis. Interval mapping in the F(2) generation from intercrosses of the LG/J and SM/J strains revealed 33 QTL affecting mandible shape. The QTL effects corresponded to a variety of shape changes, but ordination or a parametric bootstrap test of clustering did not reveal any distinct groups of QTL that would affect primarily one module or the other. The correlations of landmark positions between the two modules tended to be lower than the correlations between arbitrary subsets of landmarks, indicating that the modules were relatively independent of each other and confirming the hypothesized location of the boundary between them. While these results are in agreement with the hypothesis of modularity, they also underscore that modularity is a question of the relative degrees to which QTL contribute to different traits, rather than a question of discrete sets of QTL contributing to discrete sets of traits.

Genetic influence on daily wheel running activity level

Abstract: This project was designed to determine the genetic (between-strain) and environmental (within-strain) variance in daily running wheel activity level in inbred mice. Five male and five female mice, ...

A dynamic trust model for mobile ad hoc networks

Abstract: This paper introduces a trust model for mobile ad hoc networks. Initially each node is assigned a trust level. Then we use several approaches to dynamically update trust levels by using reports from threat detection tools, such as intrusion detection systems (IDS), located on all nodes in the network. The nodes neighboring to a node exhibiting suspicious behavior initiate trust reports. These trust reports are propagated through the network using one of our proposed methods. A source node can use the trust levels it establishes for other nodes to evaluate the security of routes to destination nodes. Using these trust levels as a guide, the source node can then select a route that meets the security requirements of the message to be transmitted. This paper demonstrates important concepts for establishing a collaborative, dynamic trust model and for using this model as an example to enhance the security of message routing in mobile ad hoc networks.

AUTHORS' RESPONSE: "The Foundations of Posttraumatic Growth: New Considerations"

Abstract: In response to comments on our model of posttraumatic growth, we consider the validity of reports of posttraumatic growth, appropriate methodology to use to assess posttraumatic growth, and its relation with other variables that appear to bear a resemblance to posttraumatic growth (e.g., well-being and psychological adjustment). The potentially important role of proximate and distal cultural factors is also addressed. Clinicians are encouraged to use interventions that facilitate posttraumatic growth with care, so as not to create expectations for posttraumatic growth in all trauma survivors, and to instead promote a respect for the difficulty of trauma recovery while allowing for the exploration of possibilities for various kinds of growth even in those who have suffered greatly.

Frontal lobe damage and tests of executive processing: a meta-analysis of the category test, stroop test, and trail-making test.

Abstract: The Category Test, Trails B, and the interference task of the Stroop Test are among the most commonly administered measures of frontal lobe functioning and are thought to tap different cognitive functions mediated by these brain regions. Two meta-analyses were conducted on these tests to determine their sensitivity to frontal and lateralized frontal brain damage. Study 1 compared participants with frontal lobe damage to those with damage to posterior brain regions, whereas Study 2 compared participants with left and right frontal lobe damage. For each study, effect sizes based on performance differences between the above groups were calculated for the Category Test, Trail-Making Test Parts A and B, and the Stroop Test, including Word, Color, and Color-Word subtests. In Study 1 significant differences between groups were found for Trails A and all Stroop tasks, but in Study 2 the only difference between left and right frontal participants was on the Stroop Color-Word task. Potential reasons why Trails A and the Stroop Test are sensitive to frontal lobe damage are discussed, such as novelty and processing speed, as are clinical implications of these findings. The challenges of research on assessment of frontal lobe functioning are discussed and new developments in this area are highlighted.

Service Climate Effects on Customer Attitudes: An Examination of Boundary Conditions

Abstract: Our aim in this study was to extend theory on service climate by examining two boundary conditions for the effects of service climate on customer attitudes. We hypothesized that (1) the more proxim...

THE AFRICAN HONEY BEE: Factors Contributing to a Successful Biological Invasion*

Abstract: The African honey bee subspecies Apis mellifera scutellata has colonized much of the Americas in less than 50 years and has largely replaced European bees throughout its range in the New World. The African bee therefore provides an excellent opportunity to examine the factors that influence invasion success. We provide a synthesis of recent research on the African bee, concentrating on its ability to displace European honey bees. Specifically, we consider (a) the genetic composition of the expanding population and the symmetry of gene flow between African and European bees, (b) the mechanisms that favor the preservation of the African genome, and (c) the possible range and impact of the African bee in the United States.

Participation’s Influence on Job Satisfaction The Importance of Job Characteristics

Abstract: A structural equationmodel was proposed to analyze the impact of employee participation and job characteristics on job satisfaction. The current study found that participative decision making has a significant positive effect on performance feedback, task significance, and career development support. Performance feedback was positively related to job specificity and career development support. Task significance and career development support were, in turn, positively related to job satisfaction. These findings suggest that participation has an important, albeit indirect, effect on employee job satisfaction through its influence on job characteristics. The implications of these findings for public management are discussed.

Student Involvement in Individualized Education Program Meetings

Abstract: We conducted a review of the literature to investigate interventions designed to increase students' involvement in their individualized education program (IEP) process. Sixteen studies were identified and analyzed in terms of six variables: purpose, participants/setting, design, dependent variables, independent variable, and results. Our findings suggest that students with widely varying disabilities can be actively involved in the IEP process. Our results also indicate that both published curricula designed to teach students skills to enhance their participation prior to IEP meetings and person-centered planning strategies are effective in increasing students' involvement in their IEP meetings, as substantiated through direct observation; scores on measures of self-determination; and/or feedback from participants, parents, and teachers. We discuss the results in terms of implications for practice and research, the need for future studies to assess the impact of student participation on students' daily li...

A Framework for Assessing the Business Value of Information Technology Infrastructures

Abstract: Information technology (IT) infrastructure investments are an extremely important part of e-business and constitute a major portion of IT investments in many organizations. IT infrastructure investments include investments in connectivity, systems integration, and data storage that may be used by multiple applications. Prior research has recognized the importance of a flexible IT infrastructure as a source of competitive advantage. Evidence regarding the value of IT infrastructures is anecdotal, and there is a realization that large investments in IT infrastructures are often difficult to justify. This paper expands on the idea that the value of an IT infrastructure depends on its use in an organizational context, and presents a relatively simple approach to understanding and assessing the value of IT infrastructure investments. This approach is based on the asset valuation literature in finance. An example is provided to illustrate the proposed approach, and managerial implications are discussed.

Cadmium-induced apoptosis in oyster hemocytes involves disturbance of cellular energy balance but no mitochondrial permeability transition.

Abstract: SUMMARY Exposure to environmentally prevalent heavy metals such as cadmium can have detrimental effects on a variety of commercially and ecologically important species such as oysters. Since Cd 2+ is known to induce apoptosis in immune cells of vertebrates, we have investigated the effects of this metal on isolated oyster hemocytes, the main cellular immune defense in mollusks. Enhanced apoptosis of these cells could conceivably create immunosuppressed conditions in these organisms and result in reduced disease resistance and increased opportunistic infection, resulting in decline of their populations. Cd 2+ exposure induced apoptosis in oyster hemocytes in a dose-dependent manner in the range of 10-100 μmol l -1 , as indicated by the translocation of phosphatidylserine to the outer leaflet of the plasma membrane. At higher concentrations (200-1000 μmol l -1 ), there was no further increase in apoptosis but a significant increase in the level of necrosis. In stark contrast to vertebrate immune cells, there was no decrease in the mitochondrial membrane potential or activation of caspases in response to Cd 2+ in the apoptotic range. Surprisingly, Cd 2+ exposure in this range did cause a significant decrease in intracellular ATP levels, indicating a severe disturbance of energy metabolism. Similarly, Cd 2+ exposure of isolated mitochondria resulted in partial uncoupling of mitochondria but no difference in mitochondrial membrane potential. The results demonstrate that the important environmental pollutant Cd 2+ induces apoptosis in oyster immune cells and does so through a mitochondria/caspase-independent pathway, suggesting that a novel, perhaps ancient, apoptotic pathway is active in these cells. Furthermore, it appears that the observed decrease in ATP production during apoptosis is not due to the loss of the mitochondrial proton-motive force but is more likely to be due to inhibition of the F 0 /F 1 -ATPase and/or mitochondrial ADP/ATP or substrate transport.

A Comparison of Verbal and Written Descriptions of Students' Problem Solving Processes.

Abstract: The purpose of this exploratory study was to investigate the impact of writing during mathematical problem solving. The study involved an analysis of ninth grade algebra students' written and verbal descriptions of their mathematical problem solving processes. Through this comparison, a better understanding of the connection between problem solving and writing is realized. The written and verbal data show a relationship between the number of problem solving strategies tried by students and their success. The majority of problem solving behaviors involve execution actions such as carrying out goals and performing calculations. Students who construct global plans are more successful problem solvers. Students engage in verification behaviors at various stages of problem solving though the majority of students do not verify their final answers. While both oral and written descriptions serve as a tool for understanding students' thinking processes, a comparison of the two modes of reporting, using a metacognitive framework as the lens of analysis, reveals some important variations. Students who wrote descriptions of their thinking were significantly more successful in the problem solving tasks (p< 0.05) than students who verbalized their thinking. Differences in metacognitive behaviors also support the premise that writing can be an effective tool in supporting metacognitive behaviors.

Identity-Based Threshold Decryption

Abstract: In this paper, we examine issues related to the construction of identity-based threshold decryption schemes and argue that it is important in practice to design an identity-based threshold decryption scheme in which a private key associated with an identity is shared. A major contribution of this paper is to construct the first identity-based threshold decryption scheme secure against chosen-ciphertext attack. A formal proof of security of the scheme is provided in the random oracle model, assuming the Bilinear Diffie-Hellman problem is computationally hard. Another contribution of this paper is, by extending the proposed identity-based threshold decryption scheme, to construct a mediated identity-based encryption scheme secure against more powerful attacks than those considered previously.

Oil price volatility and the asymmetric response of gasoline prices to oil price increases and decreases

Abstract: This paper analyzes the effect of volatility in oil prices on the degree of asymmetry in the response of gasoline prices to oil price increases and decreases. Several time series measures of the asymmetry between the responses of gasoline prices to oil price increases and decreases and several measures of the oil price volatility are constructed. In all models, the degree of asymmetry in gasoline prices declines with an increase in oil price volatility. The results support the oligopolistic coordination theory as a likely explanation of the observed asymmetry and are not consistent with the standard search theory and the search theory with Bayesian updating.

Cadmium effects on mitochondrial function are enhanced by elevated temperatures in a marine poikilotherm, Crassostrea virginica Gmelin (Bivalvia: Ostreidae).

Abstract: SUMMARY Marine intertidal mollusks, such as oysters, are exposed to multiple stressors in estuaries, including varying environmental temperature and levels of trace metals, which may interactively affect their physiology. In order to understand the combined effects of cadmium and elevated temperature on mitochondrial bioenergetics of marine mollusks, respiration rates and mitochondrial volume changes were studied in response to different cadmium levels (0–1000 μmol l –1 ) and temperatures (15, 25 and 35°C) in isolated mitochondria from the eastern oyster Crassostrea virginica acclimated at 15°C. It was found that both cadmium and temperature significantly affect mitochondrial function in oysters. Elevated temperature had a rate-enhancing effect on state 3 (ADP-stimulated) and states 4 and 4+ (representative of proton leak) respiration, and the rate of temperature-dependent increase was higher for states 4 and 4+ than for state 3 respiration. Exposure of oyster mitochondria to 35°C resulted in a decreased respiratory control and phosphorylation efficiency (P/O ratio) compared to that of the acclimation temperature (15°C), while an intermediate temperature (25°C) had no effect. Cadmium exposure did not lead to a significant volume change in oyster mitochondria in vitro . Low levels of cadmium (1–5 μmol l –1 ) stimulated the rate of proton leak in oyster mitochondria, while not affecting ADP-stimulated state 3 respiration. In contrast, higher cadmium levels (10–50 μmol l –1 ) had little or no effect on proton leak, but significantly inhibited state 3 respiration by 40–80% of the control rates. Elevated temperature increased sensitivity of oyster mitochondria to cadmium leading to an early inhibition of ADP-stimulated respiration and an onset of complete mitochondrial uncoupling at progressively lower cadmium concentrations with increasing temperature. Enhancement of cadmium effects by elevated temperatures suggests that oyster populations subjected to elevated temperatures due to seasonal warming or global climate change may become more susceptible to trace metal pollution, and vice versa .

ClassView: hierarchical video shot classification, indexing, and accessing

Abstract: Recent advances in digital video compression and networks have made video more accessible than ever. However, the existing content-based video retrieval systems still suffer from the following problems. 1) Semantics-sensitive video classification problem because of the semantic gap between low-level visual features and high-level semantic visual concepts; 2) Integrated video access problem because of the lack of efficient video database indexing, automatic video annotation, and concept-oriented summary organization techniques. In this paper, we have proposed a novel framework, called ClassView, to make some advances toward more efficient video database indexing and access. 1) A hierarchical semantics-sensitive video classifier is proposed to shorten the semantic gap. The hierarchical tree structure of the semantics-sensitive video classifier is derived from the domain-dependent concept hierarchy of video contents in a database. Relevance analysis is used for selecting the discriminating visual features with suitable importances. The Expectation-Maximization (EM) algorithm is also used to determine the classification rule for each visual concept node in the classifier. 2) A hierarchical video database indexing and summary presentation technique is proposed to support more effective video access over a large-scale database. The hierarchical tree structure of our video database indexing scheme is determined by the domain-dependent concept hierarchy which is also used for video classification. The presentation of visual summary is also integrated with the inherent hierarchical video database indexing tree structure. Integrating video access with efficient database indexing tree structure has provided great opportunity for supporting more powerful video search engines.