Mean zonal flows generated by librations of a rotating spherical cavity

Longitudinal librations represent oscillations about the axis of a rotating axisymmetric fluid-filled cavity. An analytical theory is developed for the case of a spherical cavity in the limit when the libration frequency is small in comparison with the rotation rate, but large in comparison with the inverse of the spin-up time. It is shown that longitudinal librations create a steady zonal flow through the nonlinear advection in the Ekman layers. The theory can be applied to laboratory experiments as well as to solid planets and satellites with a liquid core. Copyright © Cambridge University Press 2010.

Zonal flow induced by longitudinal librations of a rotating cylindrical cavity

Longitudinal librations represent oscillations about the axis of a rotating axisymmetric fluid filled cavity. An analytical theory is developed for the case of a cylindrical cavity in the limit when the libration frequency is small in comparison with the rotation rate, but large in comparison with the inverse of the spin-up time. It is shown that through the nonlinear advection in the Ekman layers the librations cause the fluid to rotate more slowly. © 2010 Elsevier B.V. All rights reserved.

Genetic analysis of dyslexia candidate genes in the European cross-linguistic NeuroDys cohort

Dyslexia is one of the most common childhood disorders with a prevalence of around 5-10% in school-age children. Although an important genetic component is known to have a role in the aetiology of dyslexia, we are far from understanding the molecular mechanisms leading to the disorder. Several candidate genes have been implicated in dyslexia, including DYX1C1, DCDC2, KIAA0319, and the MRPL19/C2ORF3 locus, each with reports of both positive and no replications. We generated a European cross-linguistic sample of school-age children-the NeuroDys cohort-that includes more than 900 individuals with dyslexia, sampled with homogenous inclusion criteria across eight European countries, and a comparable number of controls. Here, we describe association analysis of the dyslexia candidate genes/locus in the NeuroDys cohort. We performed both case-control and quantitative association analyses of single markers and haplotypes previously reported to be dyslexia-associated. Although we observed association signals in samples from single countries, we did not find any marker or haplotype that was significantly associated with either case-control status or quantitative measurements of word-reading or spelling in the meta-analysis of all eight countries combined. Like in other neurocognitive disorders, our findings underline the need for larger sample sizes to validate possibly weak genetic effects. © 2014 Macmillan Publishers Limited All rights reserved.

Specification and quantitative analysis of probabilistic cloud deployment patterns

Cloud computing is a new technological paradigm offering computing infrastructure, software and platforms as a pay-as-you-go, subscription-based service. Many potential customers of cloud services require essential cost assessments to be undertaken before transitioning to the cloud. Current assessment techniques are imprecise as they rely on simplified specifications of resource requirements that fail to account for probabilistic variations in usage. In this paper, we address these problems and propose a new probabilistic pattern modelling (PPM) approach to cloud costing and resource usage verification. Our approach is based on a concise expression of probabilistic resource usage patterns translated to Markov decision processes (MDPs). Key costing and usage queries are identified and expressed in a probabilistic variant of temporal logic and calculated to a high degree of precision using quantitative verification techniques. The PPM cost assessment approach has been implemented as a Java library and validated with a case study and scalability experiments. © 2012 Springer-Verlag Berlin Heidelberg.

Employee engagement in the public sector:a narrative evidence synthesis

It has been claimed that employee engagement can harness public service motivation in ways that lead to better improve functioning and positive organizational outcomes, and can help address the increasingly complex challenges associated with public service in an era of austerity. Despite this, there has not yet been a systematic review of the literature that would enable researchers to understand more about the antecedent factors and the outcomes of engagement in the public sector. To address this issue, we undertook a systematic narrative synthesis of the empirical research on engagement that yielded 5111 published studies, of which just 59 were conducted in public sector settings and met our inclusion criteria. Studies generally found that motivational features of jobs (such as autonomy), group (such as social support), management (such as leader consideration), and organizations (such as voice mechanisms) as well as psychological resources were key antecedents of engagement within the public sector; and that engagement was associated with positive employee health/morale and enhanced performance behaviors. The evidence was far from conclusive, suggesting a need for much more rigorous research focused on the specific challenges of public sector settings. We make recommendations for further research on this important topic, particularly with regards to understanding the connection between public service motivation and engagement and the need to examine engagement across different public sector/service contexts.

The meaning, antecedents and outcomes of employee engagement:a narrative synthesis

The claim that high levels of engagement can enhance organizational performance and individual well-being has not previously been tested through a systematic review of the evidence. To bring coherence to the diffuse body of literature on engagement, the authors conducted a systematic synthesis of narrative evidence involving 214 studies focused on the meaning, antecedents and outcomes of engagement. The authors identified six distinct conceptualizations of engagement, with the field dominated by the Utrecht Group's ‘work engagement’ construct and measure, and by the theorization of engagement within the ‘job demands–resources’ framework. Five groups of factors served as antecedents to engagement: psychological states; job design; leadership; organizational and team factors; and organizational interventions. Engagement was found to be positively associated with individual morale, task performance, extra-role performance and organizational performance, and the evidence was most robust in relation to task performance. However, there was an over-reliance on quantitative, cross-sectional and self-report studies within the field, which limited claims of causality. To address controversies over the commonly used measures and concepts in the field and gaps in the evidence-base, the authors set out an agenda for future research that integrates emerging critical sociological perspectives on engagement with the psychological perspectives that currently dominate the field.

The relationship between perceived training and development and employee retention:the mediating role of work attitudes

This paper considers how utilizing a model of job-related affect can be used to explain the processes through which perceived training and development influence employee retention. We applied Russell’s model of core affect to categorize four different forms of work attitude, and positioned these as mediators of the relationship between perceived training and development and intention to stay. Using data from 1,191 employees across seven organizations, multilevel analyses found that job satisfaction, employee engagement, and change-related anxiety were significantly associated with intention to stay, and fully mediated the relationship between perceived training and development and intention to stay. Contrary to our hypotheses, emotional exhaustion was not significantly associated with intention to stay nor acted as a mediator when the other attitudes were included. These findings show the usefulness of Russell’s model of core affect in explaining the link between training and development and employee retention. Moreover, the findings collectively suggest that studies examining employee retention should include a wider range of work attitudes that highlight pleasant forms of affect.