143 research outputs found

    A Determination of the Relative Efficacy of Different Techniques for Employee Benefit Communication

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    This study used 103 employees from a large electronics firm as subjects in examining relative efficacy of 3 methods of benefit communication. Use of ANOVA revealed significant differences in benefit knowledge between experimental and control groups at the posttests. There was little relation ship found between benefit knowledge and benefit satisfaction. Implica tions of these findings for practitioners and researchers are discussed.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Morphology Transformation of Foldamer Assemblies Triggered by Single Oxygen Atom on Critical Residue Switch

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    The synthesis of morphologically well-defined peptidic materials via self-assembly is challenging but demanding for biocompatible functional materials. Moreover, switching morphology from a given shape to other predictable forms by molecular modification of the identical building block is an even more complicated subject because the self-assembly of flexible peptides is prone to diverge upon subtle structural change. To accomplish controllable morphology transformation, systematic self-assembly studies are performed using congener short β-peptide foldamers to find a minimal structural change that alters the self-assembled morphology. Introduction of oxygen-containing β-amino acid (ATFC) for subtle electronic perturbation on hydrophobic foldamer induces a previously inaccessible solid-state conformational split to generate the most susceptible modification site for morphology transformation of the foldamer assemblies. The site-dependent morphological switching power of ATFC is further demonstrated by dual substitution experiments and proven by crystallographic analyses. Stepwise morphology transformation is shown by modifying an identical foldamer scaffold. This study will guide in designing peptidic molecules from scratch to create complex and biofunctional assemblies with nonspherical shapes

    The Hubble Space Telescope Wide Field Camera 3 Early Release Science data: Panchromatic Faint Object Counts for 0.2-2 microns wavelength

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    We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early Release Science (ERS) observations in the Great Observatories Origins Deep Survey (GOODS) South field. The new WFC3 ERS data provide calibrated, drizzled mosaics in the UV filters F225W, F275W, and F336W, as well as in the near-IR filters F098M (Ys), F125W (J), and F160W (H) with 1-2 HST orbits per filter. Together with the existing HST Advanced Camera for Surveys (ACS) GOODS-South mosaics in the BViz filters, these panchromatic 10-band ERS data cover 40-50 square arcmin at 0.2-1.7 {\mu}m in wavelength at 0.07-0.15" FWHM resolution and 0.090" Multidrizzled pixels to depths of AB\simeq 26.0-27.0 mag (5-{\sigma}) for point sources, and AB\simeq 25.5-26.5 mag for compact galaxies. In this paper, we describe: a) the scientific rationale, and the data taking plus reduction procedures of the panchromatic 10-band ERS mosaics; b) the procedure of generating object catalogs across the 10 different ERS filters, and the specific star-galaxy separation techniques used; and c) the reliability and completeness of the object catalogs from the WFC3 ERS mosaics. The excellent 0.07-0.15" FWHM resolution of HST/WFC3 and ACS makes star- galaxy separation straightforward over a factor of 10 in wavelength to AB\simeq 25-26 mag from the UV to the near-IR, respectively.Comment: 51 pages, 71 figures Accepted to ApJS 2011.01.2

    Comparative Îą-Helicity of Cyclic Pentapeptides in Water

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    Helix-constrained polypeptides have attracted great interest for modulating protein-protein interactions (PPI). It is not known which are the most effective helix-inducing strategies for designing PPI agonists/antagonists. Cyclization linkers (X-1-X-5) were compared here, using circular dichroism and 2D NMR spectroscopy, for a-helix induction in simple model pentapeptides, Ac-cyclo(1,5)-[X-1-Ala-Ala-Ala-X-5]-NH2, in water. In this very stringent test of helix induction, a Lys1 -> Asp5 lactam linker conferred greatest alpha-helicity, hydrocarbon and triazole linkers induced a mix of alpha- and 3(10)-helicity, while thio-and dithioether linkers produced less helicity. The lactam-linked cyclic pentapeptide was also the most effective a-helix nucleator attached to a 13-residue model peptide

    JWST NIRCam Photometry: A Study of Globular Clusters Surrounding Bright Elliptical Galaxy VV 191a at z=0.0513

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    James Webb Space Telescope NIRCam images have revealed 443 globular cluster (GC) candidates around the z=0.0513z=0.0513 elliptical galaxy VV 191a. NIRCam broadband observations are made at 0.9-4.5 μ\mum using filters F090W, F150W, F356W, and F444W. Using photometry, the data is analyzed to present color-magnitude diagrams (CMDs) that suggest a fairly uniform population of GCs. Color histograms show a unimodal color distribution that is well fit by a single Gaussian, using color to primarily trace the metallicity. The findings show the sample's globular cluster luminosity function (GCLF) does not reach the turnover value and is, therefore, more luminous than what is typically expected, with an absolute AB magnitude, MF090W=−8.70M_{F090W} = -8.70 mag, reaching within nearly one magnitude of the classical turnover value. We attribute this to the completeness in the sample. Models show that the mass estimate of the GCs detected tends to be more massive, reaching upward of ≃107M⊙\simeq 10^7 M_{\odot}. However, the results show that current GC models do not quite align with the data. We find that the models appear to be bluer than the JWST data in the reddest (F356W-F444W) filters and redder than the data in the bluest (F090W-F150W) filters and may need to be revised to improve the modeling of near-IR colors of old, metal-poor stellar populations.Comment: 11 pages, 7 figure

    Direct momentum imaging of charge transfer following site-selective ionization

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    We study ultrafast charge rearrangement in dissociating 2-iodopropane (2−C3H7I) using site-selective core ionization at the iodine atom. Clear signatures of electron transfer between the neutral propyl fragment and multiply charged iodine ions are observed in the recorded delay-dependent ion momentum distributions. The detected charge-transfer pathway is only favorable within a small (few angstroms), charge-state-dependent spatial window located at C-I distances longer than that of the neutral ground-state molecule. These results offer insights into the physics underpinning charge transfer in isolated molecules and pave the way for a different class of time-resolved studies

    Magellanic System Stars Identified in the SMACS J0723.3-7327 JWST ERO Images

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    We identify 68 distant stars in JWST/NIRCam ERO images of the field of galaxy cluster SMACS J0723.3-7327 (SMACS 0723). Given the relatively small (∼\sim10∘10^{\circ}) angular separation between SMACS 0723 and the Large Magellanic Cloud, it is likely that these stars are associated with the LMC outskirts or Leading Arm. This is further bolstered by a spectral energy distribution analysis, which suggests an excess of stars at a physical distance of 40−10040-100 kpc, consistent with being associated with or located behind the Magellanic system. In particular, we find that the overall surface density of stars brighter than 27.0 mag in the field of SMACS 0723 is ∼\sim2.3 times that of stars in a blank field with similar galactic latitude (the North Ecliptic Pole Time Domain Field), and that the density of stars in the SMACS 0723 field with SED-derived distances consistent with the Magellanic system is ∼\sim7.3 times larger than that of the blank field. The candidate stars at these distances are consistent with a stellar population at the same distance modulus with [Fe/H] =−1.0= -1.0 and an age of ∼\sim5.05.0 Gyr. On the assumption that all of the 68 stars are associated with the LMC, then the stellar density of the LMC at the location of the SMACS 0723 field is ∼\sim710710 stars kpc−3^{-3}, which helps trace the density of stars in the LMC outskirts.Comment: Submitted to ApJ, comments welcom

    PEARLS: A Potentially Isolated Quiescent Dwarf Galaxy with a TRGB Distance of 31 Mpc

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    A wealth of observations have long suggested that the vast majority of isolated classical dwarf galaxies (M∗=107M_*=10^7-10910^9 M⊙_\odot) are currently star-forming. However, recent observations of the large abundance of "Ultra-Diffuse Galaxies" beyond the reach of previous large spectroscopic surveys suggest that our understanding of the dwarf galaxy population may be incomplete. Here we report the serendipitous discovery of an isolated quiescent dwarf galaxy in the nearby Universe, which was imaged as part of the PEARLS GTO program. Remarkably, individual red-giant branch stars are visible in this near-IR imaging, suggesting a distance of 3131 Mpc, and a wealth of archival photometry point to an sSFR of 2×10−122\times10^{-12} yr−1^{-1}. Spectra obtained with the Lowell Discovery Telescope find a recessional velocity consistent with the Hubble Flow and >1500{>}1500 km/s separated from the nearest massive galaxy in SDSS, suggesting that this galaxy was either quenched from internal mechanisms or had a very high-velocity interaction with a nearby massive galaxy in the past. This analysis highlights the possibility that many nearby quiescent dwarf galaxies are waiting to be discovered and that JWST has the potential to identify them.Comment: Submitted to ApJ Letters. Comments welcome
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