851 research outputs found

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

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    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 Role of Human Resource Practices in Petro-Chemical Refinery Performance

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    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

    Membrane interactions of the synthetic N-terminal peptide of HIV-1 gp41 and its structural analogs

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    AbstractStructural and functional studies assessed the membrane actions of the N terminus of HIV-1 glycoprotein 41 000 (gp41). Earlier site-directed mutagenesis has shown that key amino acid changes in this gp41 domain inhibit viral infection and syncytia formation. Here, a synthetic peptide corresponding to the N terminus of gp41 (FP; 23 residues, 519–541), and also FP analogs (FP520V/E with Val→Glu at residue 520; FP527L/R with Leu→Arg at 527; FP529F/Y with Phe→Tyr at 529; and FPCLP1 with FP truncated at 525) incorporating these modifications were prepared. When added to human erythrocytes at physiologic pH, the lytic and aggregating activities of the FP analogs were much reduced over those with the wild-type FP. With resealed human erythrocyte ghosts, the lipid-mixing activities of the FP analogs were also substantially depressed over that with the wild-type FP. Combined with results from earlier studies, theoretical calculations using hydrophobic moment plot analysis and physical experiments using circular dichroism and Fourier transform infrared spectroscopy indicate that the diminished lysis and fusion noted for FP analogs may be due to altered peptide-membrane lipid interactions. These data confirm that the N-terminal gp41 domain plays critical roles in the cytolysis and fusion underlying HIV-cell infection

    JME 4110 Senior Design Project - C.H.E.T.

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    C.H.E.T. is designed to be a educational tool for children of ages 6-12 that are interested in mechanical equipment and mechanical concepts. C.H.E.T. provides a simple hydraulic system that incorporates linkages, cylinders, springs, pins and other mechanical features to operate the excavator assembly. We wanted to design and build an educational toy that is fun, reliable. educational, hands-on and yet still affordable for typical families

    The ACS Virgo Cluster Survey IV: Data Reduction Procedures for Surface Brightness Fluctuation Measurements with the Advanced Camera for Surveys

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    The Advanced Camera for Surveys (ACS) Virgo Cluster Survey is a large program to image 100 early-type Virgo galaxies using the F475W and F850LP bandpasses of the Wide Field Channel of the ACS instrument on the Hubble Space Telescope (HST). The scientific goals of this survey include an exploration of the three-dimensional structure of the Virgo Cluster and a critical examination of the usefulness of the globular cluster luminosity function as a distance indicator. Both of these issues require accurate distances for the full sample of 100 program galaxies. In this paper, we describe our data reduction procedures and examine the feasibility of accurate distance measurements using the method of surface brightness fluctuations (SBF) applied to the ACS Virgo Cluster Survey F850LP imaging. The ACS exhibits significant geometrical distortions due to its off-axis location in the HST focal plane; correcting for these distortions by resampling the pixel values onto an undistorted frame results in pixel correlations that depend on the nature of the interpolation kernel used for the resampling. This poses a major challenge for the SBF technique, which normally assumes a flat power spectrum for the noise. We investigate a number of different interpolation kernels and show through an analysis of simulated galaxy images having realistic noise properties that it is possible, depending on the kernel, to measure SBF distances using distortion-corrected ACS images without introducing significant additional error from the resampling. We conclude by showing examples of real image power spectra from our survey.Comment: ApJS, in press, complete version of the paper at the link: http://www.physics.rutgers.edu/~pcote/acs/publications.htm

    Presence of Juvenile Blackfin Snapper, Lutjanus buccanella, and Snowy Grouper, Epinephelus niveatus, on Shallow-water Artificial Reefs

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    The inshore environment of Broward County, Florida consists of three reef tracts, each separated by sand substrate, running parallel to the coastline in sequentially deeper water. A wide variety of artificial reef designs have been deployed in Broward County, many lying in sand flats between the reeftracts. From 1995 through 2002, over 1,100 visual fish censuses (predominantly point-counts) were completed on the three natural reeftracts in water depths from 3 m to 30 m and over 1,100 censuses were done on artificial reefs at depths of 7 m to 23 m. Curiously, the juvenile stages of two deeper-water species of the snapper/grouper complex, the blackfin snapper (Lutjanus buccanella) and the snowy grouper (Epinephelus niveatus), appear to prefer artificial reefs located in the sand flat separating the second and third reeftracts to nearby natural reef areas. Five hundred and forty blackfin snapper have been recorded in 64 visual censuses and nine snowy grouper have been observed in seven counts on artificial reefs. Despite the large volume of visual census data collected thus far, these two species have never been recorded on nearby natural reef tracts. The reasons for this unanticipated observation is unclear but it provides an excellent launch-point for an examination of juvenile habitat requirements, natural availability of these requirements, and the potential for artificial substrate to be used in managing these species

    Earthworm effects on the incorporation of litter C and N into soil organic matter in a sugar maple forest

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    To examine the mechanisms of earthworm effects on forest soil C and N, we double-labeled leaf litter with C-13 and N-15, applied it to sugar maple forest plots with and without earthworms, and traced isotopes into soil pools. The experimental design included forest plots with different earthworm community composition (dominated by Lumbricus terrestris or L. rubellus). Soil carbon pools were 37% lower in earthworm-invaded plots largely because of the elimination of the forest floor horizons, and mineral soil C:N was lower in earthworm plots despite the mixing of high C:N organic matter into soil by earthworms. Litter disappearance over the first winter-spring was highest in the L. terrestris (T) plots, but during the warm season, rapid loss of litter was observed in both L. rubellus (R) and T plots. After two years, 22.0% +/- 5.4% of C-13 released from litter was recovered in soil with no significant differences among plots. Total recovery of added C-13 (decaying litter plus soil) was much higher in no-worm (NW) plots (61-68%) than in R and T plots (20-29%) as much of the litter remained in the former whereas it had disappeared in the latter. Much higher percentage recovery of N-15 than C-13 was observed, with significantly lower values for T than R and NW plots. Higher overwinter earthworm activity in T plots contributed to lower soil N recovery. In earthworm-invaded plots isotope enrichment was highest in macroaggregates and microaggregates whereas in NW plots silt plus clay fractions were most enriched. The net effect of litter mixing and priming of recalcitrant soil organic matter (SOM), stabilization of SOM in soil aggregates, and alteration of the soil microbial community by earthworm activity results in loss of SOM and lowering of the C:N ratio. We suggest that earthworm stoichiometry plays a fundamental role in regulating C and N dynamics of forest SOM

    Divergent expression patterns of pituitary gonadotropin subunit and GnRH receptor genes to continuous GnRH in vitro and in vivo.

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    Continuous, as opposed to pulsatile, delivery of hypothalamic gonadotropin-releasing hormone (GnRH) leads to a marked decrease in secretion of pituitary gonadotropins LH and FSH and impairment of reproductive function. Here we studied the expression profile of gonadotropin subunit and GnRH receptor genes in rat pituitary in vitro and in vivo to clarify their expression profiles in the absence and continuous presence of GnRH. Culturing of pituitary cells in GnRH-free conditions downregulated Fshb, Cga, and Gnrhr expression, whereas continuous treatment with GnRH agonists upregulated Cga expression progressively and Gnrhr and Fshb expression transiently, accompanied by a prolonged blockade of Fshb but not Gnrhr expression. In contrast, Lhb expression was relatively insensitive to loss of endogenous GnRH and continuous treatment with GnRH, probably reflecting the status of Egr1 and Nr5a1 expression. Similar patterns of responses were observed in vivo after administration of a GnRH agonist. However, continuous treatment with GnRH stimulated LH secretion in vitro and in vivo, leading to decrease in LH cell content despite high basal Lhb expression. These data suggest that blockade of Fshb expression and depletion of the LH secretory pool are two major factors accounting for weakening of the gonadotroph secretory function during continuous GnRH treatment

    Efficacy of acupuncture for chronic low back pain: protocol for a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Chronic back pain is a major public health problem and the primary reason patients seek acupuncture treatment. Therefore, an objective assessment of acupuncture efficacy is critical for making informed decisions about its appropriate role for patients with this common condition. This study addresses methodological shortcomings that have plagued previous studies evaluating acupuncture for chronic low back pain.</p> <p>Methods and Design</p> <p>A total of 640 participants (160 in each of four arms) between the ages of 18 and 70 years of age who have low back pain lasting at least 3 months will be recruited from integrated health care delivery systems in Seattle and Oakland. They will be randomized to one of two forms of Traditional Chinese Medical (TCM) acupuncture needling (individualized or standardized), a "control" group (simulated acupuncture), or to continued usual medical care. Ten treatments will be provided over 7 weeks. Study participants and the "Diagnostician" acupuncturists who evaluate participants and propose individualized treatments will be masked to the acupuncture treatment actually assigned each participant. The "Therapist" acupuncturists providing the treatments will not be masked but will have limited verbal interaction with participants. The primary outcomes, standard measures of dysfunction and bothersomeness of low back pain, will be assessed at baseline, and after 8, 26, and 52 weeks by telephone interviewers masked to treatment assignment. General health status, satisfaction with back care, days of back-related disability, and use and costs of healthcare services for back pain will also be measured. The primary analysis comparing outcomes by randomized treatment assignment will be analysis of covariance adjusted for baseline value. For both primary outcome measures, this trial will have 99% power to detect the presence of a minimal clinically significant difference among all four treatment groups and over 80% power for most pairwise comparisons. Secondary analyses will compare the proportions of participants in each group that improve by a clinically meaningful amount.</p> <p>Conclusion</p> <p>Results of this trial will help clarify the value of acupuncture needling as a treatment for chronic low back pain.</p> <p>Trial registration</p> <p>Clinical Trials.gov NCT00065585.</p
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