The Experts below are selected from a list of 337461 Experts worldwide ranked by ideXlab platform

P Ring - One of the best experts on this subject based on the ideXlab platform.

  • relativistic rpa in axial symmetry
    arXiv: Nuclear Theory, 2009
    Co-Authors: Pena D Arteaga, P Ring
    Abstract:

    Covariant density functional theory, in the framework of self-consistent Relativistic Mean Field (RMF) and Relativistic Random Phase approximation (RPA), is for the first time applied to axially deformed nuclei. The fully self-consistent RMF+RRPA equations are posed for the case of axial symmetry and non-linear energy functionals, and solved with the help of a new parallel code. Formal properties of RPA theory are studied and special care is taken in order to validate the proper decoupling of spurious modes and their influence on the physical Response. Sample applications to the magnetic and electric dipole transitions in $^{20}$Ne are presented and analyzed.

  • relativistic random phase approximation in axial symmetry
    Physical Review C, 2008
    Co-Authors: Daniel Pena Arteaga, P Ring
    Abstract:

    Covariant density functional theory, in the framework of self-consistent relativistic mean field (RMF) and relativistic random-phase approximation (RRPA), is for the first time applied to axially deformed nuclei. The fully self-consistent RMF+RRPA equations are posed for the case of axial symmetry and nonlinear energy functionals and solved with the help of a new parallel code. Formal properties of RPA theory are studied and special care is taken to validate the proper decoupling of spurious modes and their influence on the physical Response. Sample applications to the magnetic and electric dipole transitions in $^{20}\mathrm{Ne}$ are presented and analyzed.

Helen Lingard - One of the best experts on this subject based on the ideXlab platform.

  • occupational stress and job demand control and support factors among construction project consultants
    International Journal of Project Management, 2014
    Co-Authors: Peter J Edwards, Helen Lingard
    Abstract:

    Abstract Occupational stress affects the health and wellbeing of people who work, and the construction industry is recognized as a high-stress working environment. The relationship between job demands, job control, workplace support, and experiences of stress in the South African construction context is investigated, using hierarchical regression, factor analysis and structural equation modeling to explore the strength of thirteen factor relationships with perceived stress. Data were gathered from an on-line questionnaire survey Response Sample of 676 architects, civil engineers, quantity surveyors, and project and construction managers. Predictors displaying a significant relationship with occupational stress are the presence of work–life imbalance, the need to ‘prove’ oneself, hours worked per week, working to tight deadlines, and support from line managers in difficult situations at work. Existing theories of occupational stress are confirmed but not completely supported. The construction industry should give attention to how the need to work long hours is justified. Organizations should look to improving managerial and collegial support for construction professionals, but be careful in engaging in socializing and project team-building activities. Further research will need to focus more deeply on construction-specific job demand factors; explore why women professionals appear to experience more stress than men; and aim to develop reliable early-warning detection techniques for construction professionals.

Paul J Rathouz - One of the best experts on this subject based on the ideXlab platform.

  • longitudinal studies of binary Response data following case control and stratified case control sampling design and analysis
    Biometrics, 2010
    Co-Authors: Jonathan S Schildcrout, Paul J Rathouz
    Abstract:

    We discuss design and analysis of longitudinal studies after case-control sampling, wherein interest is in the relationship between a longitudinal binary Response that is related to the sampling (case-control) variable, and a set of covariates. We propose a semiparametric modeling framework based on a marginal longitudinal binary Response model and an ancillary model for subjects' case-control status. In this approach, the analyst must posit the population prevalence of being a case, which is then used to compute an offset term in the ancillary model. Parameter estimates from this model are used to compute offsets for the longitudinal Response model. Examining the impact of population prevalence and ancillary model misspecification, we show that time-invariant covariate parameter estimates, other than the intercept, are reasonably robust, but intercept and time-varying covariate parameter estimates can be sensitive to such misspecification. We study design and analysis issues impacting study efficiency, namely: choice of sampling variable and the strength of its relationship to the Response, Sample stratification, choice of working covariance weighting, and degree of flexibility of the ancillary model. The research is motivated by a longitudinal study following case-control sampling of the time course of attention deficit hyperactivity disorder (ADHD) symptoms.

Peter J Edwards - One of the best experts on this subject based on the ideXlab platform.

  • occupational stress and job demand control and support factors among construction project consultants
    International Journal of Project Management, 2014
    Co-Authors: Peter J Edwards, Helen Lingard
    Abstract:

    Abstract Occupational stress affects the health and wellbeing of people who work, and the construction industry is recognized as a high-stress working environment. The relationship between job demands, job control, workplace support, and experiences of stress in the South African construction context is investigated, using hierarchical regression, factor analysis and structural equation modeling to explore the strength of thirteen factor relationships with perceived stress. Data were gathered from an on-line questionnaire survey Response Sample of 676 architects, civil engineers, quantity surveyors, and project and construction managers. Predictors displaying a significant relationship with occupational stress are the presence of work–life imbalance, the need to ‘prove’ oneself, hours worked per week, working to tight deadlines, and support from line managers in difficult situations at work. Existing theories of occupational stress are confirmed but not completely supported. The construction industry should give attention to how the need to work long hours is justified. Organizations should look to improving managerial and collegial support for construction professionals, but be careful in engaging in socializing and project team-building activities. Further research will need to focus more deeply on construction-specific job demand factors; explore why women professionals appear to experience more stress than men; and aim to develop reliable early-warning detection techniques for construction professionals.

Jonathan S Schildcrout - One of the best experts on this subject based on the ideXlab platform.

  • longitudinal studies of binary Response data following case control and stratified case control sampling design and analysis
    Biometrics, 2010
    Co-Authors: Jonathan S Schildcrout, Paul J Rathouz
    Abstract:

    We discuss design and analysis of longitudinal studies after case-control sampling, wherein interest is in the relationship between a longitudinal binary Response that is related to the sampling (case-control) variable, and a set of covariates. We propose a semiparametric modeling framework based on a marginal longitudinal binary Response model and an ancillary model for subjects' case-control status. In this approach, the analyst must posit the population prevalence of being a case, which is then used to compute an offset term in the ancillary model. Parameter estimates from this model are used to compute offsets for the longitudinal Response model. Examining the impact of population prevalence and ancillary model misspecification, we show that time-invariant covariate parameter estimates, other than the intercept, are reasonably robust, but intercept and time-varying covariate parameter estimates can be sensitive to such misspecification. We study design and analysis issues impacting study efficiency, namely: choice of sampling variable and the strength of its relationship to the Response, Sample stratification, choice of working covariance weighting, and degree of flexibility of the ancillary model. The research is motivated by a longitudinal study following case-control sampling of the time course of attention deficit hyperactivity disorder (ADHD) symptoms.