The Role of Human Resource Practices in Petro-Chemical Refinery Performance

This study examined the impact of Human Resource (HR) practices (selection, training, compensation, and appraisal) and participation on the financial performance of U.S. petrochemical refineries. Survey results from HR and Operations respondents indicated that appraisal and training were significantly related to workforce skills and that training and compensation were marginally related to workforce motivation. In addition, only training was significantly related to refinery performance, although the relationship was negative. However, selection, compensation, and appraisal interacted with participation in determining refinery financial performance such that each of these practices were strongly positively related to financial performance only under highly participative systems. Implications are discussed

Strategy, Core Competence and HR Involvement as Determinants of HR Effectiveness and Refinery Performance

This study examined the impact strategy, core competence, and involvement of HR executives in strategic decision making on the refinery managers\u27 evaluation of the effectiveness of HR and refinery performance among 86 U.S. petro-chemical refineries. Survey results indicated that higher involvement of HR in organizational strategy was strongly related to perceptions of HR effectiveness, and that the relationship was strongest to the extent that refineries pursued a product innovation strategy and viewed skilled employees as their core competence. HR involvement was unrelated to refinery performance, but was actually negatively related to the extent that refineries emphasized efficient production as their core competence

The agrin gene codes for a family of basal lamina proteins that differ in function and distribution

We isolated two cDNAs that encode isoforms of agrin, the basal lamina protein that mediates the motor neuron-induced aggregation of acetylcholine receptors on muscle fibers at the neuromuscular junction. Both proteins are the result of alternative splicing of the product of the agrin gene, but, unlike agrin, they are inactive in standard acetylcholine receptor aggregation assays. They lack one (agrin-related protein 1) or two (agrin-related protein 2) regions in agrin that are required for its activity. Expression studies provide evidence that both proteins are present in the nervous system and muscle and that, in muscle, myofibers and Schwann cells synthesize the agrin-related proteins while the axon terminals of motor neurons are the sole source of agrin

A Gamma-frailty proportional hazards model for bivariate interval-censored data

Correlated survival data naturally arise from many clinical and epidemiological studies. For the analysis of such data, the Gamma-frailty proportional hazards (PH) model is a popular choice because the regression parameters have marginal interpretations and the statistical association between the failure times can be explicitly quantified via Kendall’s tau. Despite their popularity, Gamma-frailty PH models for correlated interval-censored data have not received as much attention as analogous models for right-censored data. A Gamma-frailty PH model for bivariate interval-censored data is presented and an easy to implement expectation–maximization (EM) algorithm for model fitting is developed. The proposed model adopts a monotone spline representation for the purposes of approximating the unknown conditional cumulative baseline hazard functions, significantly reducing the number of unknown parameters while retaining modeling flexibility. The EM algorithm was derived from a data augmentation procedure involving latent Poisson random variables. Extensive numerical studies illustrate that the proposed method can provide reliable estimation and valid inference, and is moreover robust to the misspecification of the frailty distribution. To further illustrate its use, the proposed method is used to analyze data from an epidemiological study of sexually transmitted infections

Community Clinic-based Approach to Address Pediatric Obesity among a Predominantly Latino Sample of Youth Enrolled in a State Health Plan

Background and Purpose: Comprehensive weight management interventions with family involvement are effective in reducing obesity among children and youth. This prospective cohort study examined whether youth who participated in a clinic-based, culturally-sensitive pediatric weight management intervention experienced reductions in BMI percentile, percent body fat, and waist circumference, from baseline to the end of the program. Methods: Participants included 240 children and youth (61.3% male) between ages 5 to 18 years (Mean age= 12.8 + 3.7 years), and nearly all of them were of Latino race/ethnicity. All participants were clinically diagnosed as overweight or obese and were referred to participate in the eight-week intervention, which included standard medical consultations, psychological counseling, and physical activity sessions for the youth participants, and nutrition education for their parents. Participants completed baseline and end-of-the-program assessments. Results: Participants experienced significant decreases in BMI percentile and body fat percentage after adjusting for growth in height. Older children were more likely to experience decreases in waist circumference relative to younger children. Conclusion: This study suggests that a clinic-based, culturally sensitive intervention may effectively reduce indicators of obesity among youth in predominantly Latino communities, beyond changes in these indicators due to normal growth

Hubbard-U calculations for Cu from first-principles Wannier functions

We present first-principles calculations of optimally localized Wannier functions for Cu and use these for an ab-initio determination of Hubbard (Coulomb) matrix elements. We use a standard linearized muffin-tin orbital calculation in the atomic-sphere approximation (LMTO-ASA) to calculate Bloch functions, and from these determine maximally localized Wannier functions using a method proposed by Marzari and Vanderbilt. The resulting functions were highly localized, with greater than 89% of the norm of the function within the central site for the occupied Wannier states. Two methods for calculating Coulomb matrix elements from Wannier functions are presented and applied to fcc Cu. For the unscreened on-site Hubbard $U$ for the Cu 3d-bands we have obtained about 25eV. These results are also compared with results obtained from a constrained local-density approximation (LDA) calculation.Comment: 13 pages, 8 figures, 5 table

On the constitution of sodium at higher densities

Using density functional theory the atomic and electronic structure of sodium are predicted to depart substantially from those expected of simple metals for $r_s 130$ GPa). Newly-predicted phases include those with low structural symmetry, semi-metallic electronic properties (including zero-gap semiconducting limiting behavior), unconventional valence charge density distributions, and even those that raise the possibility of superconductivity, all at currently achievable pressures. Important differences emerge between sodium and lithium at high densities, and these are attributable to corresponding differences in their respective cores.Comment: 13 pages; 3 figure

Spectral Properties of delta-Plutonium: Sensitivity to 5f Occupancy

By combining the local density approximation (LDA) with dynamical mean field theory (DMFT), we report a systematic analysis of the spectral properties of $\delta$-plutonium with varying $5f$ occupancy. The LDA Hamiltonian is extracted from a tight-binding (TB) fit to full-potential linearized augmented plane-wave (FP-LAPW) calculations. The DMFT equations are solved by the exact quantum Monte Carlo (QMC) method and the Hubbard-I approximation. We have shown for the first time the strong sensitivity of the spectral properties to the $5f$ occupancy, which suggests using this occupancy as a fitting parameter in addition to the Hubbard $U$. By comparing with PES data, we conclude that the ``open shell'' $5f^{5}$ configuration gives the best agreement, resolving the controversy over $5f$ ``open shell'' versus ``close shell'' atomic configurations in $\delta$-Pu.Comment: 6 pages, 2 embedded color figures, to appear in Physical Review

The Cerium volume collapse: Results from the LDA+DMFT approach

The merger of density-functional theory in the local density approximation (LDA) and many-body dynamical mean field theory (DMFT) allows for an ab initio calculation of Ce including the inherent 4f electronic correlations. We solve the DMFT equations by the quantum Monte Carlo (QMC) technique and calculate the Ce energy, spectrum, and double occupancy as a function of volume. At low temperatures, the correlation energy exhibits an anomalous region of negative curvature which drives the system towards a thermodynamic instability, i.e., the $\gamma$-to-$\alpha$ volume collapse, consistent with experiment. The connection of the energetic with the spectral evolution shows that the physical origin of the energy anomaly and, thus, the volume collapse is the appearance of a quasiparticle resonance in the 4f-spectrum which is accompanied by a rapid growth in the double occupancy.Comment: 4 pages, 3 figure