4,239 research outputs found

    Wellness Project Implementation Within Houston\u27s Faith and Diabetes initiative: a Mixed Methods Study

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    BACKGROUND: Faith-based health promotion has shown promise for supporting healthy lifestyles, but has limited evidence of reaching scale or sustainability. In one recent such effort, volunteers from a diverse range of faith organizations were trained as peer educators to implement diabetes self-management education (DSME) classes within their communities. The purpose of this study was to identify factors associated with provision of these classes within six months of peer-educator training. METHODS: This study used the Consolidated Framework for Implementation Research (CFIR) to identify patterns from interviews, observations, attendance records, and organizational background information. Two research team members thematically coded interview transcripts and observation memos to identify patterns distinguishing faith organizations that did, versus did not, conduct DSME classes within six months of peer-educator training. Bivariate statistics were also used to identify faith organizational characteristics associated with DSME class completion within this time frame. RESULTS: Volunteers from 24 faith organizations received peer-educator training. Of these, 15 led a DSME class within six months, graduating a total of 132 participants. Thematic analyses yielded two challenges experienced disproportionately by organizations unable to complete DSME within six months: [1] Their peer educators experienced DSME as complex, despite substantial planning efforts at simplification, and [2] the process of engaging peer educators and leadership within their organizations was often more difficult than anticipated, despite initial communication by Faith and Diabetes organizers intended to secure informed commitments by both groups. Many peer educators were overwhelmed by training content, the responsibility required to start and sustain DSME classes, and other time commitments. Other priorities competed for time in participants\u27 lives and on organizational calendars, and scheduling processes could be slow. In an apparent dynamic of crowding out, coordination was particularly difficult in larger organizations, which were less likely than smaller organizations to complete DSME classes despite their more substantial resources. CONCLUSIONS: Initial commitment from faith organizations\u27 leadership and volunteers may not suffice to implement even relatively short and low cost health promotion programs. Faith organizations might benefit from realistic previews about just how challenging it is to make these programs a sufficiently high organizational and individual priority

    Estimating the age of fire in the Cape flora of South Africa from an orchid phylogeny

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    Fire may have been a crucial component in the evolution of the Cape flora of South Africa, a region characterized by outstanding levels of species richness and endemism. However, there is, to date, no critical assessment of the age of the modern fire regime in this biome. Here, we exploit the presence of two obligate post-fire flowering clades in the orchid genus Disa, in conjunction with a robust, well-sampled and dated molecular phylogeny, to estimate the age by which fire must have been present. Our results indicate that summer drought (winter rainfall), the fire regime and the fynbos vegetation are several million years older than currently suggested. Summer drought and the fynbos vegetation are estimated to date back to at least the Early Miocene (ca 19.5 Ma). The current fire regime may have been established during a period of global cooling that followed the mid-Miocene Climatic Optimum (ca 15 Ma), which led to the expansion of open habitats and increased aridification. The first appearance of Disa species in the grassland biome, as well as in the subalpine habitat, is in striking agreement with reliable geological and palaeontological evidence of the age of these ecosystems, thus corroborating the efficacy of our methods. These results change our understanding of the historical mechanisms underlying botanical evolution in southern Africa, and confirm the potential of using molecular phylogenies to date events for which other information is lacking or inconclusive

    Reducing Zero-point Systematics in Dark Energy Supernova Experiments

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    We study the effect of filter zero-point uncertainties on future supernova dark energy missions. Fitting for calibration parameters using simultaneous analysis of all Type Ia supernova standard candles achieves a significant improvement over more traditional fit methods. This conclusion is robust under diverse experimental configurations (number of observed supernovae, maximum survey redshift, inclusion of additional systematics). This approach to supernova fitting considerably eases otherwise stringent mission calibration requirements. As an example we simulate a space-based mission based on the proposed JDEM satellite; however the method and conclusions are general and valid for any future supernova dark energy mission, ground or space-based.Comment: 30 pages,8 figures, 5 table, one reference added, submitted to Astroparticle Physic

    Long-range epidemic spreading with immunization

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    We study the phase transition between survival and extinction in an epidemic process with long-range interactions and immunization. This model can be viewed as the well-known general epidemic process (GEP) in which nearest-neighbor interactions are replaced by Levy flights over distances r which are distributed as P(r) ~ r^(-d-sigma). By extensive numerical simulations we confirm previous field-theoretical results obtained by Janssen et al. [Eur. Phys. J. B7, 137 (1999)].Comment: LaTeX, 14 pages, 4 eps figure

    Reticulation, Data Combination, and Inferring Evolutionary History: An Example from Danthonioideae (Poaceae)

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    We explore the potential impact of conflicting gene trees on inferences of evolutionary history above the species level. When conflict between gene trees is discovered, it is common practice either to analyze the data separately or to combine the data having excluded the conflicting taxa or data partitions for those taxa (which are then recoded as missing). We demonstrate an alternative approach, which involves duplicating conflicting taxa in the matrix, such that each duplicate is represented by one partition only. This allows the combination of all available data in standard phylogenetic analyses, despite reticulations. We show how interpretation of contradictory gene trees can lead to conflicting inferences of both morphological evolution and biogeographic history, using the example of the pampas grasses, Cortaderia. The characteristic morphological syndrome of Cortaderia can be inferred as having arisen multiple times (chloroplast DNA [cpDNA]) or just once (nuclear ribosomal DNA [nrDNA]). The distributions of species of Cortaderia and related genera in Australia/New Guinea, New Zealand, and South America can be explained by few (nrDNA) or several (cpDNA) dispersals between the southern continents. These contradictions can be explained by past hybridization events, which have linked gains of complex morphologies with unrelated chloroplast lineages and have erased evidence of dispersals from the nuclear genome. Given the discrepancies between inferences based on the gene trees individually, we urge the use of approaches such as ours that take multiple gene trees into accoun

    Galaxy Selection and Clustering and Lyman alpha Absorber Identification

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    The effects of galaxy selection on our ability to constrain the nature of weak Ly\alpha absorbers at low redshift are explored. Current observations indicate the existence of a population of gas-rich, low surface brightness (LSB) galaxies, and these galaxies may have large cross sections for Ly\alpha absorption. Absorption arising in LSB galaxies may be attributed to HSB galaxies at larger impact parameters from quasar lines of sight, so that the observed absorption cross sections of galaxies may seem unreasonably large. Thus it is not possible to rule out scenarios where LSB galaxies make substantial contributions to Ly\alpha absorption using direct observations. Less direct tests, where observational selection effects are taken into account using simulations, should make it possible to determine the nature of Ly\alpha absorbers by observing a sample of ~100 galaxies around quasar lines of sight with well-defined selection criteria. Such tests, which involve comparing simulated and observed plots of the unidentified absorber fractions and absorbing galaxy fractions versus impact parameter, can distinguish between scenarios where absorbers arise in particular galaxies and those where absorbers arise in gas tracing the large scale galaxy distribution. Care must be taken to minimize selection effects even when using these tests. Results from such tests are likely to depend upon the limiting neutral hydrogen column density. While not enough data are currently available to make a strong conclusion about the nature of moderately weak absorbers, evidence is seen that such absorbers arise in gas that is around or between galaxies that are often not detected in surveys.Comment: 15 pages, 10 figures, accepted to the Astrophysical Journa

    Quasar Proper Motions and Low-Frequency Gravitational Waves

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    We report observational upper limits on the mass-energy of the cosmological gravitational-wave background, from limits on proper motions of quasars. Gravitational waves with periods longer than the time span of observations produce a simple pattern of apparent proper motions over the sky, composed primarily of second-order transverse vector spherical harmonics. A fit of such harmonics to measured motions yields a 95%-confidence limit on the mass-energy of gravitational waves with frequencies <2e-9 Hz, of <0.11/h*h times the closure density of the universe.Comment: 15 pages, 1 figure. Also available at http://charm.physics.ucsb.edu:80/people/cgwinn/cgwinn_group/index.htm

    Effect of in-plane magnetic field on the photoluminescence spectrum of modulation-doped quantum wells and heterojunctions

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    The photoluminescence (PL) spectrum of modulation-doped GaAs/AlGaAs quantum wells (MDQW) and heterojunctions (HJ) is studied under a magnetic field (BB_{\|}) applied parallel to the two-dimensional electron gas (2DEG) layer. The effect of BB_{\|} strongly depends on the electron-hole separation (dehd_{eh}), and we revealed remarkable BB_{\|}-induced modifications of the PL spectra in both types of heterostructures. A model considering the direct optical transitions between the conduction and valence subband that are shifted in k-space under BB_{\|}, accounts qualitatively for the observed spectral modifications. In the HJs, the PL intensity of the bulk excitons is strongly reduced relatively to that of the 2DEG with increasing BB_{\|}. This means that the distance between the photoholes and the 2DEG decreases with increased BB_{\|}, and that free holes are responsible for the hole-2DEG PL.Comment: 6pages, 5figure
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