5,996 research outputs found

    Li I and K I Scatter in Cool Pleiades Dwarfs

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    We utilize high-resolution (R~60,000), high S/N (~100) spectroscopy of 17 cool Pleiades dwarfs to examine the confounding star-to-star scatter in the 6707 Li I line strengths in this young cluster. Our Pleiads, selected for their small projected rotational velocity and modest chromospheric emission, evince substantial scatter in the linestrengths of 6707 Li I feature that is absent in the 7699 K I resonance line. The Li I scatter is not correlated with that in the high-excitation 7774 O I feature, and the magnitude of the former is greater than the latter despite the larger temperature sensitivity of the O I feature. These results suggest that systematic errors in linestrength measurements due to blending, color (or color-based T_eff) errors, or line formation effects related to an overlying chromosphere are not the principal source of Li I scatter in our stars. There do exist analytic spot models that can produce the observed Li scatter without introducing scatter in the K I line strengths or the color-magnitude diagram. However, these models predict factor of >3 differences in abundances derived from the subordinate 6104 and resonance 6707 Li I features; we find no difference in the abundances determined from these two features. These analytic spot models also predict CN line strengths significantly larger than we observe in our spectra. The simplest explanation of the Li, K, CN, and photometric data is that there must be a real abundance component to the Pleiades Li dispersion. We suggest that this real abundance component is the manifestation of relic differences in erstwhile pre-main-sequence Li burning caused by effects of surface activity on stellar structure. We discuss observational predictions of these effects.Comment: 35 pages, 7 figures; accepted by Ap

    Measurement invariance across chronic conditions: a systematic review and an empirical investigation of the Health Education Impact Questionnaire (heiQ™).

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    To examine whether lack of measurement invariance (MI) influences mean comparisons among different disease groups, this paper provides (1) a systematic review of MI in generic constructs across chronic conditions and (2) an empirical analysis of MI in the Health Education Impact Questionnaire (heiQ™)

    A co-design approach to service improvement resulted in teams exhibiting characteristics that support innovation

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    This paper analyzes a subset of data from a project that sought to transfer knowledge and skills around design led approaches for service improvement to teams working in Health and Social Care in the United Kingdom. Through this analysis the authors sought to understand the range of responses that individual participants had to undertaking service improvement work in a design led project. This was a qualitative study using interviews to gain reflections from participants. These interview transcripts were analyzed using framework analysis. Participants were recruited from three disparate organizations, a public health team of a local authority, a mental health charity and a UK National Health Service mental health initiative. Six main themes were identified, namely; design practice, collaborative working, creating an environment for innovation, team skills and attitudes and transfer of knowledge. The findings suggest that the design approach can contribute to a range of factors that have been identified as valuable for innovative teams. The paper adds to the evidence base and supports further exploration of the use of design in Service improvement and wider innovation endeavours

    Movement of transgenic plant-expressed Bt Cry1Ac proteins through high trophic levels

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    The movement of Bacillus thuringiensis (Berliner) (Bt) Cry1Ac endotoxin through high trophic levels was assessed to help elucidate the effects of Bt toxin on non-target insects. The diamondback moth (Plutella xylostella L., Lepidoptera: Plutellidae), the parasitic wasp (Cotesia vestalis Haliday, Hymenoptera: Braconidae) and the predatory green lacewing Chrysoperla carnea (Stephen) (Neuroptera: Chrysopidae) were used as a model system in this laboratory study. Bt-resistant P. xylostella larvae fed Cry1Ac-expressing transgenic oilseed rape (OSR, Brassica napus L., Cruciferae), before and after parasitization by C. vestalis, consumed Cry1Ac with the ingested plant material but only a proportion of Cry1Ac consumed was recovered from the bodies and faeces of P. xylostella larvae. Cry1Ac was not detected in newly emerged parasitoid larvae. In contrast, Cry1Ac was detected in C. carnea larvae fed on resistant P. xylostella larvae reared on Bt OSR. However, no Cry1Ac could be detected in C. carnea larvae when the lacewings were transferred to P. xylostella larvae reared on conventional OSR and tested 24-48 h. The metabolizing ability of Cry1Ac is discussed for the larvae of P. xylostella and C. carnea

    Lightweight Bulldozer Attachment for Construction and Excavation on the Lunar Surface

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    A lightweight bulldozer blade prototype has been designed and built to be used as an excavation implement in conjunction with the NASA Chariot lunar mobility platform prototype. The combined system was then used in a variety of field tests in order to characterize structural loads, excavation performance and learn about the operational behavior of lunar excavation in geotechnical lunar simulants. The purpose of this effort was to evaluate the feasibility of lunar excavation for site preparation at a planned NASA lunar outpost. Once the feasibility has been determined then the technology will become available as a candidate element in the NASA Lunar Surface Systems Architecture. In addition to NASA experimental testing of the LANCE blade, NASA engineers completed analytical work on the expected draft forces using classical soil mechanics methods. The Colorado School of Mines (CSM) team utilized finite element analysis (FEA) to study the interaction between the cutting edge of the LANCE blade and the surface of soil. FEA was also used to examine various load cases and their effect on the lightweight structure of the LANCE blade. Overall it has been determined that a lunar bulldozer blade is a viable technology for lunar outpost site preparation, but further work is required to characterize the behavior in 1/6th G and actual lunar regolith in a vacuum lunar environment

    Investigating the microbial community of Cacopsylla spp. as potential factor in vector competence of phytoplasma

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    Phytoplasmas are obligatory intracellular bacteria that colonize the phloem of many plant species and cause hundreds of plant diseases worldwide. In nature, phytoplasmas are primarily transmitted by hemipteran vectors. While all phloem-feeding insects could in principle transmit phytoplasmas, only a limited number of species have been confirmed as vectors. Knowledge about factors that might determine the vector capacity is currently scarce. Here, we characterized the microbiomes of vector and non-vector species of apple proliferation (AP) phytoplasma ‘Candidatus Phytoplasma mali’ to investigate their potential role in the vector capacity of the host. We performed high-throughput 16S rRNA metabarcoding of the two principal AP-vectors Cacopsylla picta and Cacopsylla melanoneura and eight Cacopsylla species, which are not AP-vectors but co-occur in apple orchards. The microbiomes of all species are dominated by Carsonella, the primary endosymbiont of psyllids and a second uncharacterized Enterobacteriaceae endosymbiont. Each Cacopsylla species harboured a speciesspecific phylotype of both symbionts. Moreover, we investigated differences between the microbiomes of AP-vector versus non-vector species and identified the predominant endosymbionts but also Wolbachia and several minor taxa as potential indicator species. Our study highlights the importance of considering the microbiome in future investigations of potential factors influencing host vector competence. We investigated the potential role of symbiotic bacteria in the acquisition and transmission of phytoplasma. By comparing the two main psyillid vector species of Apple proliferation (AP) phytoplasma and eight co-occurring species, which are not able to vector AP-phytoplasma, we found differences in the microbial communities of AP-vector and non-vector species, which appear to be driven by the predominant symbionts in both vector species and Wolbachia and several minor taxa in the non-vector species. In contrast, infection with APphytoplasma did not affect microbiome composition in both vector species. Our study provides new insights into the endosymbiont diversity of Cacopsylla spp. and highlights the importance of considering the microbiome when investigating potential factors influencing host vector competenc

    Assessing health status over time:Impact of recall period and anchor question on the minimal clinically important difference of copd health status tools

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    BACKGROUND: The Minimal Clinically Important Difference (MCID) assesses what change on a measurement tool can be considered minimal clinically relevant. Although the recall period can influence questionnaire scores, it is unclear if it influences the MCID. This study is the first to examine longitudinally the impact of the recall period of an anchor question and its design on the MCID of COPD health status tools using the COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) and the St. George's Respiratory Questionnaire (SGRQ). METHODS: Moderate to very severe COPD patients without respiratory co-morbidities were recruited during 3-week Pulmonary Rehabilitation (PR). CAT, CCQ and SGRQ were completed at baseline, discharge, 3, 6, 9 and 12 months. A 15-point Global Rating of Change scale (GRC) was completed at each follow-up. A five-point GRC was used as second anchor at 12 months. Mean change scores of a subset of patients indicating a minimal improvement on each of the anchor questions were considered the MCID. The MCID estimates over different time periods were compared with one another by evaluating the degree of overlap of Confidence Intervals (CI) adjusted for dependency. RESULTS: In total 451 patients were included (57.9 ± 6.6 years, 65% male, 50/39/11% GOLD II/III/IV), of which 309 completed follow-up. Baseline health status scores were 20.2 ± 7.3 (CAT), 2.9 ± 1.2 (CCQ) and 50.7 ± 17.3 (SGRQ). MCID estimates for improvement ranged - 3.1 to - 1.4 for CAT, - 0.6 to - 0.3 for CCQ, and - 10.3 to - 7.6 for SGRQ. Absolute higher - though not significant - MCIDs were observed for CAT and CCQ directly after PR. Significantly absolute lower MCID estimates were observed for CAT (difference - 1.4: CI -2.3 to - 0.5) and CCQ (difference - 0.2: CI -0.3 to -0.1) using a five-point GRC. CONCLUSIONS: The recall period of a 15-point anchor question seemed to have limited impact on the MCID for improvement of CAT, CCQ and SGRQ during PR; although a 3-week MCID estimate directly after PR might lead to absolute higher values. However, the design of the anchor question was likely to influence the MCID of CAT and CCQ. TRIAL REGISTRATION: RIMTCORE trial # DRKS00004609 and #12107 (Ethik-Kommission der Bayerischen Landesärztekammer)

    Soft Contributions to Hard Pion Photoproduction

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    Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We estimate the soft contributions to this process, with an eye toward delineating the region where perturbatively calculable processes dominate. Our soft process estimate is based on vector meson dominance and data based parameterizations of semiexclusive hadronic cross sections. We find that soft processes dominate in single pion photoproduction somewhat past 2 GeV transverse momentum at a few times 10 GeV incoming energy. The recent polarization asymmetry data is consistent with the perturbative asymmetry being diluted by polarization insensitive soft processes. Determining the polarized gluon distribution using hard pion photoproduction appears feasible with a few hundred GeV incoming energy (in the target rest frame).Comment: 6 pages, 5 figure

    Nuclear Magnetic Resonance and Hyperfine Structure

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    Contains research objectives and reports on six research objectives
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