George Michaelides

The clinical spectrum of de novo donor-specific antibodies in pediatric renal transplant recipients

The development of donor‐specific HLA antibodies (DSA) is associated with worse renal allograft survival in adult patients. This study assessed the natural history of de novo DSA, and its impact on renal function in pediatric renal transplant recipients (RTR). HLA antibodies were measured prospectively using single‐antigen‐bead assays at 1, 3, 6 and 12 months posttransplant followed by 12‐monthly intervals and during episodes of allograft dysfunction. Of 215 patients with HLA antibody monitoring, 75 (35%) developed DSA at median of 0.25 years posttransplant with a high prevalence of Class II (70%) and HLA‐DQ (45%) DSA. DSA resolved in 35 (47%) patients and was associated with earlier detection (median, inter‐quartile range 0.14, 0.09–0.33 vs. 0.84, 0.15–2.37 years) and lower mean fluorescence intensity (MFI) (2658, 1573–3819 vs. 7820, 5166–11 990). Overall, DSA positive patients had more rapid GFR decline with a 50% reduction in GFR at mean 5.3 (CI: 4.7–5.8) years versus 6.1 (5.7–6.4) years in DSA negative patients (p = 0.02). GFR decreased by a magnitude of 1 mL/min/1.73 m2 per log10 increase in Class II DSA MFI (p < 0.01). Using Cox regression, independent factors predicting poorer renal allograft outcome were older age at transplant (hazard ratio 1.1, CI: 1.0–1.2 per year), tubulitis (1.5, 1.3–1.8) and microvasculature injury (2.9, 1.4–5.7). In conclusion, pediatric RTR with de novo DSA and microvasculature injury were at risk of allograft failure.

Expanding the risk assessment methodology for work-related health: A technique for incorporating multivariate curvilinear effects

Abstract Although there is conceptual and empirical evidence that supports the existence of possible curvilinear relationships between job characteristics and health outcomes, risk assessments usually rely on linear estimation approaches. However, this approach may not be conducive to good risk management practice. Where curvilinear effects exist, it is possible for there to be too much of a beneficial work characteristic, or too little of one that is harmful. If that is the case then there will be an optimum level for health and well-being. This study explores a new risk estimation technique that can accommodate multivariate curvilinear relationships. The partial derivatives technique can provide stronger predictive utility, incorporate synergistic effects of predictors, and is supported by conceptual work and empirical evidence. To illustrate these ideas, a risk assessment was conducted on a sample of 354 police officers in Greece. Multivariate polynomial regression analyses indicated that a number of job characteristics salient to participants’ experiences were related to outcomes curvilinearly. A risk index (Ri) was derived from a range of values that represent the slopes of all possible lines tangential to the curve that describes the relationship between predictor and outcome. This technique may help to refine and extend current models of risk assessment for work-related health and stimulate new interest in research into risk assessment methodology.

The impact of fluctuating workloads on well-being and the mediating role of work-nonwork interference in this relationship.

Heavy workloads have been central to the discussion of well-being. However, fluctuations in workloads have received sparse attention, even though transient and routine levels of workloads may have independent effects on well-being. The article assesses this, particularly focusing on the effort-recovery model of the workload/well-being relationship in which work-nonwork interference mediates this relationship. Using data from a weekly diary study of freelance or portfolio workers, multilevel analyses showed that both routine and transient levels of work to nonwork interference mediated the job demands-calmness relationship. Work to nonwork interference also negatively mediated the hours worked-calmness relationship, but the direct relationship between hours worked and calmness was a positive one so the mediating effect reduced this positive effect. In the case of enthusiasm, which was a second measure of well-being, there were no mediating effects but both routine and nonroutine levels of job demands and transient levels of hours worked were related to it. The study highlights the value of introducing the temporal dimension into the study of the work-nonwork interface, and the diversity of relationships that occur across different dimensions of workload and well-being.

Cyberconflict at the edge of chaos: Cryptohierarchies and self-organisation in the open-source movement

This paper differentiates between different levels of conflict in the open-source movement and discusses the role conflict and self-organisation play in the emergence of structures of leadership emergence and the bifurcation into core and peripheral groups and soft control by cryptohierarchies; in the different levels of group polarisation and conflict between communities negotiating their identity, strategy, coordination and complexity; and lastly, in the dynamic relationships between hierarchies and networks. These dynamics are forcing open-source communities to exist at the edge of chaos, and to constantly engage in lines of flight and resistance from the system of global control, while ignoring current capitalist practices and ‘growing their own’ models of self-organising knowledge creation and exchange.

Workplace design: Conceptualizing and measuring workplace characteristics for motivation

Purpose – Although both job design and its broader context are likely to drive motivation, little is known about the specific workplace characteristics that are important for motivation. The purpose of this paper is to present the Workplace Characteristics Model, which describes the workplace characteristics that can foster motivation, and the corresponding multilevel Workplace Design Questionnaire. Design/methodology/approach – The model is configured as nine workplace attributes describing climate for motivation at two levels, psychological and organizational. The multilevel multi-time questionnaire was validated with data from 4,287 individuals and 212 workplaces and with integrated regulation as the criterion outcome. Findings – Multilevel factor analysis and regression indicated good internal reliability, construct validity, and stability over time, and excellent concurrent and predictive validity of the questionnaire. Practical implications – The model could help to optimize job and workplace design by contextualizing motivation. The questionnaire offers advancement over single-level climate measures as it is validated simultaneously at two levels. Further research can focus on overcoming the low response rate typical for online surveys, on need fulfillment as the mediating variable, and on the joint influence of job and workplace characteristics on organizational behavior. Originality/value – This work responds to calls to incorporate context in research into organizational behavior and job design. An understanding of the workplace is a first step in this direction. This questionnaire is the first to be validated at multiple levels of analysis. Ultimately, workplace design could support job design and the development of inherently motivating workplaces.

Challenge and hindrance stressors and wellbeing-based work–nonwork interference: A diary study of portfolio workers

Stress-based work–nonwork interference, or negative spillover, is associated with transference of negative emotions from the work to the nonwork domain. It is argued that work–nonwork interference resulting from high work demands does not necessarily entail the reproduction of any affective states. First, calmness can result in lower work–nonwork interference and enthusiasm in higher levels. Second, hindrance stressors can be negatively related to enthusiasm and calmness, while challenge stressors are positively associated with them. Hypotheses about the relationship between stressors and interference that reflect this rationality are developed and tested using longitudinal data from a six-month diary study of portfolio workers. The results offer some support for them and indicate that both challenge and hindrance stressors are positively related to interference. However, for hindrance stressors the indirect effect is positive when mediated by calmness and negative for enthusiasm. In contrast, for challenge stressors the indirect effect is negative when mediated by calmness and positive when mediated by enthusiasm. The mediation paths are significant only for transient effects. Thus, there are indications that well-being can both increase or decrease interference depending on the nature of the stressor and whether it is mediated by calmness or enthusiasm.

Everything that you have ever been told about assessment center ratings is confounded.

Despite a substantial research literature on the influence of dimensions and exercises in assessment centers (ACs), the relative impact of these 2 sources of variance continues to raise uncertainties because of confounding. With confounded effects, it is not possible to establish the degree to which any 1 effect, including those related to exercises and dimensions, influences AC ratings. In the current study (N = 698) we used Bayesian generalizability theory to unconfound all of the possible effects contributing to variance in AC ratings. Our results show that ≤1.11% of the variance in AC ratings was directly attributable to behavioral dimensions, suggesting that dimension-related effects have no practical impact on the reliability of ACs. Even when taking aggregation level into consideration, effects related to general performance and exercises accounted for almost all of the reliable variance in AC ratings. The implications of these findings for recent dimension- and exercise-based perspectives on ACs are discussed. (PsycINFO Database Record

Measuring fidelity to extreme programming: a psychometric approach

This study assesses the Shodan survey as an instrument for measuring an individual’s or a team’s adherence to the extreme programming (XP) methodology. Specifically, we hypothesize that the adherence to the XP methodology is not a uni-dimensional construct as presented by the Shodan survey but a multidimensional one reflecting dimensions that are theoretically grounded in the XP literature. Using data from software engineers in the University of Sheffield’s Software Engineering Observatory, two different models were thus tested and compared using confirmatory factor analysis: a uni-dimensional model and a four-dimensional model. We also present an exploratory analysis of how these four dimensions affect students’ grades. The results indicate that the four-dimensional model fits the data better than the uni-dimensional one. Nevertheless, the analysis also uncovered flaws with the Shodan survey in terms of the reliability of the different dimensions. The exploratory analysis revealed that some of the XP dimensions had linear or curvilinear relationship with grades. Through validating the four-dimensional model of the Shodan survey this study highlights how psychometric techniques can be used to develop software engineering metrics of fidelity to agile or other software engineering methods.

Job demands, job control, psychological climate, and job satisfaction: A cognitive dissonance perspective

Purpose: Research into job design and employee outcomes has tended to examine job design in isolation of the wider organizational context, leading to calls to attend to the context in which work is embedded. This study examines the effects of the interaction between job design and psychological climate on job satisfaction. Design/approach: Cognitive Dissonance Theory was used to explore the nature of this relationship and its effect on job satisfaction. We hypothesized that psychological climate (autonomy, competence, relatedness dimensions) augments favourable perceptions of job demands and control when there is consistency between them (augmentation effect) and compensates for unfavourable perceptions when they are inconsistent (compensation effect). Findings: Analysis of data from 3,587 individuals partially supported the hypotheses. Compensation effects were observed for job demands under a high autonomy and competence climate and for job control under a low competence climate. Augmentation effects were observed for job demands under a high relatedness climate. Research implications: Psychological climate has the power to enhance or reduce the effects of job design and this may extend to other outcomes such as performance and commitment. Practical implications: Well-designed and high-quality jobs should take into account the effects of psychological climate on employee outcomes. Originality/value: This study has offered a way to bridge the job design and psychological climate fields and demonstrated that the call for more attention to the context in which jobs are embedded is worth heeding