Showing papers by "University of Western Ontario published in 2006"

Job satisfaction, organizational commitment, turnover intention, and turnover: Path analyses based on meta-analytic findings.

Abstract: Cross-study differences in the contributions of work attitudes to the turnover process led us to (a) estimate the six relations among job satisfaction, organizational commitment, turnover intention/withdrawal cognitions, and turnover using meta-analysis; (b) assess the effects of several psychometric moderators on those relations; and (c) compare the influences of satisfaction and commitment in the turnover process by applying path analysis to the meta-analytic correlations. Based on aggregations involving a total of 178 independent samples from 155 studies, results showed that (a) satisfaction and commitment each contribute independently to the prediction of intention/cognitions; (b) intention/cognitions are predicted more strongly by satisfaction than by commitment; (c) intention/cognitions mediate nearly all of the attitu-dinal linkage with turnover; and (d) attitudinal contributions to the turnover process vary with the use of single- versus multi-item scales, the 9- versus 15-item version of the Organizational Commitment Questionnaire, and turnover intention versus withdrawal cognition scales.

Associative and propositional processes in evaluation: An integrative review of implicit and explicit attitude change.

Abstract: A central theme in recent research on attitudes is the distinction between deliberate, "explicit" attitudes and automatic, "implicit" attitudes. The present article provides an integrative review of the available evidence on implicit and explicit attitude change that is guided by a distinction between associative and propositional processes. Whereas associative processes are characterized by mere activation independent of subjective truth or falsity, propositional reasoning is concerned with the validation of evaluations and beliefs. The proposed associative-propositional evaluation (APE) model makes specific assumptions about the mutual interplay of the 2 processes, implying several mechanisms that lead to symmetric or asymmetric changes in implicit and explicit attitudes. The model integrates a broad range of empirical evidence and implies several new predictions for implicit and explicit attitude change.

Graph Cuts and Efficient N-D Image Segmentation

Abstract: Combinatorial graph cut algorithms have been successfully applied to a wide range of problems in vision and graphics. This paper focusses on possibly the simplest application of graph-cuts: segmentation of objects in image data. Despite its simplicity, this application epitomizes the best features of combinatorial graph cuts methods in vision: global optima, practical efficiency, numerical robustness, ability to fuse a wide range of visual cues and constraints, unrestricted topological properties of segments, and applicability to N-D problems. Graph cuts based approaches to object extraction have also been shown to have interesting connections with earlier segmentation methods such as snakes, geodesic active contours, and level-sets. The segmentation energies optimized by graph cuts combine boundary regularization with region-based properties in the same fashion as Mumford-Shah style functionals. We present motivation and detailed technical description of the basic combinatorial optimization framework for image segmentation via s/t graph cuts. After the general concept of using binary graph cut algorithms for object segmentation was first proposed and tested in Boykov and Jolly (2001), this idea was widely studied in computer vision and graphics communities. We provide links to a large number of known extensions based on iterative parameter re-estimation and learning, multi-scale or hierarchical approaches, narrow bands, and other techniques for demanding photo, video, and medical applications.

GIS‐based multicriteria decision analysis: a survey of the literature

Abstract: The integration of GIS and multicriteria decision analysis has attracted significant interest over the last 15 years or so This paper surveys the GIS‐based multicriteria decision analysis (GIS‐MCDA) approaches using a literature review and classification of articles from 1990 to 2004 An electronic search indicated that over 300 articles appeared in refereed journals The paper provides taxonomy of those articles and identifies trends and developments in GIS‐MCDA

Personality measures as predictors of job performance: a meta‐analytic review

Abstract: The purpose of this study was to investigate conflicting findings in previous research on personality and job performance. Meta-analysis was used to (a) assess the overall validity of personality measures as predictors of job performance, (b) investigate the moderating effects of several study characteristics on personality scale validity, and (c) appraise the predictability of job performance as a function of eight distinct categories of personality content, including the “Big Five” personality factors. Based on review of 494 studies, usable results were identified for 97 independent samples (total N= 13,521). Consistent with predictions, studies using confirmatory research strategies produced a corrected mean personality scale validity (.29) that was more than twice as high as that based on studies adopting exploratory strategies (.12). An even higher mean validity (.38) was obtained based on studies using job analysis explicitly in the selection of personality measures. Validities were also found to be higher in longer tenured samples and in published articles versus dissertations. Corrected mean validities for the “Big Five” factors ranged from .16 for Extroversion to .33 for Agreeableness. Weaknesses in the reporting of validation study characteristics are noted, and recommendations for future research in this area are provided. Contrary to conclusions of certain past reviews, the present findings provide some grounds for optimism concerning the use of personality measures in employee selection.

National Institute of Neurological Disorders and Stroke–Canadian Stroke Network Vascular Cognitive Impairment Harmonization Standards

Abstract: Background and Purpose—One in 3 individuals will experience a stroke, dementia or both. Moreover, twice as many individuals will have cognitive impairment short of dementia as either stroke or dementia. The commonly used stroke scales do not measure cognition, while dementia criteria focus on the late stages of cognitive impairment, and are heavily biased toward the diagnosis of Alzheimer disease. No commonly agreed standards exist for identifying and describing individuals with cognitive impairment, particularly in the early stages, and especially with cognitive impairment related to vascular factors, or vascular cognitive impairment. Methods—The National Institute for Neurological Disorders and Stroke (NINDS) and the Canadian Stroke Network (CSN) convened researchers in clinical diagnosis, epidemiology, neuropsychology, brain imaging, neuropathology, experimental models, biomarkers, genetics, and clinical trials to recommend minimum, common, clinical and research standards for the description and study of vascular cognitive impairment. Results—The results of these discussions are reported herein. Conclusions—The development of common standards represents a first step in a process of use, validation and refinement. Using the same standards will help identify individuals in the early stages of cognitive impairment, will make studies comparable, and by integrating knowledge, will accelerate the pace of progress. (Stroke. 2006;37:2220-2241.)

The Psychology of Humor: An Integrative Approach

Abstract: Preliminary TOC Chapter 1 Introduction to the Psychology of Humor Chapter 2 Theories and Early Research I: Psychoanalytic and Superiority Theories Chapter 3 Theories and Early Research II: Arousal, Incongruity, and Reversal Theories Chapter 4 The Cognitive Psychology of Humor Chapter 5 The Social Psychology of Humor Chapter 6 The Psychobiology of Humor and Laughter Chapter 7 Personality Approaches to Sense of Humor Chapter 8 The Developmental Psychology of Humor Chapter 9 Humor and Mental Health Chapter 10 Humor, Laughter, and Physical Health Chapter 11 Applications of Humor to Psychotherapy, Education, and the Workplace

Extending green practices across the supply chain: the impact of upstream and downstream integration

Abstract: Purpose – This research aims to extend the “collaborative paradigm” proposed by others in prior research beyond a supply chain's core operations. To date, this paradigm has generated relatively little empirical research on peripheral, non‐core areas such the natural environment. Antecedents (both plant‐level and supply chain characteristics) of green supply chain practices (GSCP) are examined. Among possible antecedents, prior research pointed to supply chain integration – both logistical (tactical level) and technological (strategic level) – as a potentially important determinant of green practices.Design/methodology/approach – Green practices are defined along the two dimensions of environmental collaboration and monitoring. The empirical analysis used data from 84 plants in North America surveyed in 2002. Validity and reliability of scales for new and existing constructs were assessed through factor analysis. Hierarchical linear regression was used to test the hypotheses for the antecedents of GSCP.Fin...

Attitude stabilization of a VTOL quadrotor aircraft

Abstract: In this paper, we propose a new quaternion-based feedback control scheme for exponential attitude stabilization of a four-rotor vertical takeoff and landing aerial robot known as a quadrotor aircraft. The proposed controller is based upon the compensation of the Coriolis and gyroscopic torques and the use of a PD/sup 2/ feedback structure, where the proportional action is in terms of the vector quaternion and the two derivative actions are in terms of the airframe angular velocity and the vector quaternion velocity. We also show that the model-independent PD controller, where the proportional action is in terms of the vector-quaternion and the derivative action is in terms of the airframe angular velocity, without compensation of the Coriolis and gyroscopic torques, provides asymptotic stability for our problem. The proposed controller as well as some other controllers have been tested experimentally on a small-scale quadrotor aircraft.

Mortality in systemic lupus erythematosus.

Abstract: Objective. To examine mortality rates in the largest systemic lupus erythematosus (SLE) cohort ever assembled. Methods. Our sample was a multisite international SLE cohort (23 centers, 9,547 patients). Deaths were ascertained by vital statistics registry linkage. Standardized mortality ratio (SMR; ratio of deaths observed to deaths expected) estimates were calculated for-all deaths and by cause. The effects of sex, age, SLE duration, race, and calendar-year periods were determined. Results. The overall SMR was 2.4 (95% confidence interval 2.3-2.5). Particularly high mortality was seen for circulatory disease, infections, renal disease, non-Hodgkin's lymphoma, and lung cancer. The highest SMR estimates were seen in patient groups characterized by female sex, younger age, SLE duration < 1 year, or black/African American race. There was a dramatic decrease in total SMR estimates across calendar-year periods, which was demonstrable for specific causes including death due to infections and death due to renal disorders. However, the SMR due to circulatory diseases tended to increase slightly from the 1970s to the year 2001. Conclusion. Our data from a very large multicenter international cohort emphasize what has been demonstrated previously in smaller samples. These results highlight the increased mortality rate in SLE patients compared with the general population, and they suggest particular risk associated with female sex, younger age, shorter SLE duration, and black/African American race. The risk for certain types of deaths, primarily related to lupus activity (such as renal disease), has decreased over time, while the risk for deaths due to circulatory disease does not appear to have diminished. (Less)

Adjuvant radiotherapy for pathologically advanced prostate cancer: a randomized clinical trial.

Abstract: ContextDespite a stage-shift to earlier cancer stages and lower tumor volumes for prostate cancer, pathologically advanced disease is detected at radical prostatectomy in 38% to 52% of patients. However, the optimal management of these patients after radical prostatectomy is unknown.ObjectiveTo determine whether adjuvant radiotherapy improves metastasis-free survival in patients with stage pT3 N0 M0 prostate cancer.Design, Setting, and PatientsRandomized, prospective, multi-institutional, US clinical trial with enrollment between August 15, 1988, and January 1, 1997 (with database frozen for statistical analysis on September 21, 2005). Patients were 425 men with pathologically advanced prostate cancer who had undergone radical prostatectomy.InterventionMen were randomly assigned to receive 60 to 64 Gy of external beam radiotherapy delivered to the prostatic fossa (n = 214) or usual care plus observation (n = 211).Main Outcome MeasuresPrimary outcome was metastasis-free survival, defined as time to first occurrence of metastatic disease or death due to any cause. Secondary outcomes included prostate-specific antigen (PSA) relapse, recurrence-free survival, overall survival, freedom from hormonal therapy, and postoperative complications.ResultsAmong the 425 men, median follow-up was 10.6 years (interquartile range, 9.2-12.7 years). For metastasis-free survival, 76 (35.5%) of 214 men in the adjuvant radiotherapy group were diagnosed with metastatic disease or died (median metastasis-free estimate, 14.7 years), compared with 91 (43.1%) of 211 (median metastasis-free estimate, 13.2 years) of those in the observation group (hazard ratio [HR], 0.75; 95% CI, 0.55-1.02; P = .06). There were no significant between-group differences for overall survival (71 deaths, median survival of 14.7 years for radiotherapy vs 83 deaths, median survival of 13.8 years for observation; HR, 0.80; 95% CI, 0.58-1.09; P = .16). PSA relapse (median PSA relapse–free survival, 10.3 years for radiotherapy vs 3.1 years for observation; HR, 0.43; 95% CI, 0.31-0.58; P<.001) and disease recurrence (median recurrence-free survival, 13.8 years for radiotherapy vs 9.9 years for observation; HR, 0.62; 95% CI, 0.46-0.82; P = .001) were both significantly reduced with radiotherapy. Adverse effects were more common with radiotherapy vs observation (23.8% vs 11.9%), including rectal complications (3.3% vs 0%), urethral strictures (17.8% vs 9.5%), and total urinary incontinence (6.5% vs 2.8%).ConclusionsIn men who had undergone radical prostatectomy for pathologically advanced prostate cancer, adjuvant radiotherapy resulted in significantly reduced risk of PSA relapse and disease recurrence, although the improvements in metastasis-free survival and overall survival were not statistically significant.Trial Registrationclinicaltrials.gov Identifier: NCT00394511

Life cycle of connexins in health and disease

Abstract: Evaluation of the human genome suggests that all members of the connexin family of gap-junction proteins have now been successfully identified. This large and diverse family of proteins facilitates a number of vital cellular functions coupled with their roles, which range from the intercellular propagation of electrical signals to the selective intercellular passage of small regulatory molecules. Importantly, the extent of gap-junctional intercellular communication is under the direct control of regulatory events associated with channel assembly and turnover, as the vast majority of connexins have remarkably short half-lives of only a few hours. Since most cell types express multiple members of the connexin family, compensatory mechanisms exist to salvage tissue function in cases when one connexin is mutated or lost. However, numerous studies of the last decade have revealed that mutations in connexin genes can also lead to severe and debilitating diseases. In many cases, single point mutations lead to dramatic effects on connexin trafficking, assembly and channel function. This review will assess the current understanding of wild-type and selected disease-linked mutant connexin transport through the secretory pathway, gap-junction assembly at the cell surface, internalization and degradation.

The impact of nursing work environments on patient safety outcomes: the mediating role of burnout/engagement.

Abstract: Objective:To test a theoretical model of professional nurse work environments linking conditions for professional nursing practice to burnout and, subsequently, patient safety outcomes.Background:The 2004 Institute of Medicine report raised serious concerns about the impact of hospital restructuring

Regulation of cancer cell migration and bone metastasis by RANKL

Abstract: Bone metastases are a frequent complication of many cancers that result in severe disease burden and pain. Since the late nineteenth century, it has been thought that the microenvironment of the local host tissue actively participates in the propensity of certain cancers to metastasize to specific organs, and that bone provides an especially fertile 'soil'. In the case of breast cancers, the local chemokine milieu is now emerging as an explanation for why these tumours preferentially metastasize to certain organs. However, as the inhibition of chemokine receptors in vivo only partially blocks metastatic behaviour, other factors must exist that regulate the preferential metastasis of breast cancer cells. Here we show that the cytokine RANKL (receptor activator of NF-kappaB ligand) triggers migration of human epithelial cancer cells and melanoma cells that express the receptor RANK. RANK is expressed on cancer cell lines and breast cancer cells in patients. In a mouse model of melanoma metastasis, in vivo neutralization of RANKL by osteoprotegerin results in complete protection from paralysis and a marked reduction in tumour burden in bones but not in other organs. Our data show that local differentiation factors such as RANKL have an important role in cell migration and the tissue-specific metastatic behaviour of cancer cells.

Greenwash: Corporate Environmental Disclosure Under Threat of Audit

Abstract: We develop an economic model of greenwash, in which a firm strategically discloses environmental information and a non-governmental organization (NGO) may audit and penalize the firm for failing to fully disclose its environmental impacts. We identify conditions under which NGO punishment of greenwash backfires, inducing the firm to become less rather than more forthcoming about its environmental performance. We show that complementarities with NGO auditing may justify public policies encouraging firms to adopt environmental management systems. Mandatory disclosure rules offer the potential for better performance than NGO auditing, but the necessary penalties may be so large as to be politically unpalatable. If so, a mix of mandatory disclosure rules, NGO auditing and environmental management systems may be needed to induce full environmental disclosure.

Crossing an Apparent Chasm: Bridging Mindful and Less-Mindful Perspectives on Organizational Learning

Abstract: An important new stream of organizational research has emerged in recent years that draws on the notion of mindfulness. At the same time, there is a long-standing body of work in the organizations literature that emphasizes the role of routine-driven, or less-mindful, behavior. We attempt to connect these two seemingly disparate literatures arguing that, at a performative level, important elements of less-mindful processes are necessary elements underlying mindfulness. In particular, we note the role of established action repertories that facilitate the response to novel stimuli and how routines and established role structures enable mindfulness to be sustained across time and the span of the organization. Similarly, we note important elements of mindfulness that underlie less-mindful behavior, highlighting in particular the role of mindfulness in interpreting one's context so as to identify what constitutes appropriate action in a given circumstance and in interpreting outcomes that form the basis for processes of reinforcement learning. Although we emphasize the complementarity between the two perspectives, we also note points of tension regarding the opportunity costs of mindfulness and the theories' implied normative claims.

Being good while being bad: social responsibility and the international diversification of US firms

Abstract: This paper contributes to the discussion on international diversification and corporate social responsibility (CSR) by suggesting that firms can be simultaneously socially responsible and socially irresponsible. To test our assertions, we analyze data from 222 publicly traded US firms from 1993 to 2003. The findings support our hypotheses, and have significant implications for the way in which we conceptualize CSR.

All in the CCN family: essential matricellular signaling modulators emerge from the bunker.

Abstract: The CCN family is a group of six secreted proteins that specifically associate with the extracellular matrix. Structurally, CCN proteins are modular, containing up to four distinct functional domains. CCN family members are induced by growth factors and cytokines such as TGFβ and endothelin 1 and cellular stress such as hypoxia, and are overexpressed in pathological conditions that affect connective tissues, including scarring, fibrosis and cancer. Although CCN family members were discovered over a decade ago, the precise biological role, mechanism of action and physiological function of these proteins has remained elusive until recently, when several key mechanistic insights into the CCN family emerged. The CCNs have been shown to have key roles as matricellular proteins, serving as adaptor molecules connecting the cell surface and extracellular matrix (ECM). Although they appear not to have specific high-affinity receptors, they signal through integrins and proteoglycans. Furthermore, in addition to having inherent adhesive abilities that modulate focal adhesions and control cell attachment and migration, they execute their functions by modulating the activity of a variety of different growth factors, such as TGFβ. CCN proteins not only regulate crucial biological processes including cell differentiation, proliferation, adhesion, migration, apoptosis, ECM production, chondrogenesis and angiogenesis, but also have more sinister roles promoting conditions such as fibrogenesis.

Oral appliances for snoring and obstructive sleep apnea: a review.

Abstract: We conducted an evidence-based review of literature regarding use of oral appliances (OAs) in the treatment of snoring and obstructive sleep apnea syndrome (OSA) from 1995 until the present. Our structured search revealed 141 articles for systematic scrutiny, of which 87 were suit- able for inclusion in the evidence base, including 15 Level I to II random- ized controlled trials and 5 of these trials with placebo-controlled treat- ment. The efficacy of OAs was established for controlling OSA in some but not all patients with success (defined as no more than 10 apneas or hypopneas per hour of sleep) achieved in an average of 52% of treated patients. Effects on sleepiness and quality of life were also demonstrated, but improvements in other neurocognitive outcomes were not consistent. The mechanism of OA therapy is related to opening of the upper airway as demonstrated by imaging and physiologic monitoring. Treatment ad- herence is variable with patients reporting using the appliance a median of 77% of nights at 1 year. Minor adverse effects were frequent whereas major adverse effects were uncommon. Minor tooth movement and small changes in the occlusion developed in some patients after prolonged use, but the long-term dental significance of this is uncertain. In comparison to continuous positive airway pressure (CPAP), OAs are less efficacious in reducing the apnea hypopnea index (AHI), but OAs appear to be used more (at least by self report), and in many studies were preferred over CPAP when the treatments were compared. OAs have also been com- pared favorably to surgical modification of the upper airway (uvulopalato- pharyngoplasty, UPPP). Comparisons between OAs of different designs have produced variable findings. The literature of OA therapy for OSA now provides better evidence for the efficacy of this treatment modality and considerable guidance regarding the frequency of adverse effects and the indications for use in comparison to CPAP and UPPP. Citation: Ferguson KA; Cartwright R; Rogers R et al. Oral Appliances for Snoring and Obstructive Sleep Apnea: A Review. SLEEP 2006;29(2): 244-262.

An information-motivation-behavioral skills model of adherence to antiretroviral therapy

Abstract: HIV-positive persons who do not maintain consistently high levels of adherence to often complex and toxic highly active antiretroviral therapy (HAART) regimens may experience therapeutic failure and deterioration of health status and may develop multidrug-resistant HIV that can be transmitted to uninfected others The current analysis conceptualizes social and psychological determinants of adherence to HAART among HIV-positive individuals The authors propose an information-motivation-behavioral skills (IMB) model of HAART adherence that assumes that adherence-related information, motivation, and behavioral skills are fundamental determinants of adherence to HAART According to the model, adherence-related information and motivation work through adherence-related behavioral skills to affect adherence to HAART Empirical support for the IMB model of adherence is presented, and its application in adherence-promotion intervention efforts is discussed

Extending the Horizons: Environmental Excellence as Key to Improving Operations

Abstract: The view that adopting an environmental perspective on operations can lead to improved operations is in itself not novel; phrases such as lean is green are increasingly commonplace. The implication is that any operational system that has minimized inefficiencies is also more environmentally sustainable. However, in this paper we argue that the underlying mechanism is one of extending the horizons of analysis and that this applies to both theory and practice of operations management. We illustrate this through two principal areas of lean operations, where we identify how successive extensions of the prevailing research horizon in each area have led to major advances in theory and practice. First, in quality management, the initial emphasis on statistical quality control of individual operations was extended through total quality management to include a broader process encompassing customer requirements and suppliers operations. More recently, the environmental perspective extended the definition of customers to stakeholders and defects to any form of waste. Second, in supply chain management, the horizon first expanded from the initial focus on optimizing inventory control with a single planner to including multiple organizations with conflicting objectives and private information. The environmental perspective draws attention to aspects such as reverse flows and end-of-life product disposal, again potentially improving the performance of the overall supply chain. In both cases, these developments were initially driven by practice, where many of the benefits of adopting an environmental perspective were unexpected. Given that these unexpected side benefits seem to recur so frequently, we refer to this phenomenon as the law of the expected unexpected side benefits. We conclude by extrapolating from the developmental paths of total quality management and supply chain management to speculate about the future of environmental research in operations management.

Calcium-dependent and -independent interactions of the S100 protein family

Abstract: The S100 proteins comprise at least 25 members, forming the largest group of EF-hand signalling proteins in humans. Although the proteins are expressed in many tissues, each S100 protein has generally been shown to have a preference for expression in one particular tissue or cell type. Three-dimensional structures of several S100 family members have shown that the proteins assume a dimeric structure consisting of two EF-hand motifs per monomer. Calcium binding to these S100 proteins, with the exception of S100A10, results in an approx. 40° alteration in the position of helix III, exposing a broad hydrophobic surface that enables the S100 proteins to interact with a variety of target proteins. More than 90 potential target proteins have been documented for the S100 proteins, including the cytoskeletal proteins tubulin, glial fibrillary acidic protein and F-actin, which have been identified mostly from in vitro experiments. In the last 5 years, efforts have concentrated on quantifying the protein interactions of the S100 proteins, identifying in vivo protein partners and understanding the molecular specificity for target protein interactions. Furthermore, the S100 proteins are the only EF-hand proteins that are known to form both homo- and hetero-dimers, and efforts are underway to determine the stabilities of these complexes and structural rationales for their formation and potential differences in their biological roles. This review highlights both the calcium-dependent and -independent interactions of the S100 proteins, with a focus on the structures of the complexes, differences and similarities in the strengths of the interactions, and preferences for homo- compared with hetero-dimeric S100 protein assembly.