4,854 research outputs found

    Separated Fringe Packet Observations with the CHARA Array III. The Very High Eccentricity Binary HR 7345

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    After an eleven year observing campaign, we present the combined visual{spectroscopic orbit of the formerly unremarkable bright star HR 7345 (HD 181655, HIP 94981, GJ 754.2). Using the Separated Fringe Packet (SFP) method with the CHARA Array, we were able to determine a difficult to complete orbital period of 331.609 +/- 0.004 days. The 11 month period causes the system to be hidden from interferometric view behind the Sun for 3 years at a time. Due to the high eccentricity orbit of about 90% of a year, after 2018 January the periastron phase will not be observable again until late 2021. Hindered by its extremely high eccentricity of 0.9322 +/- 0.0001, the double-lined spectroscopic phase of HR 7345 is observable for 15 days. Such a high eccentricity for HR 7345 places it among the most eccentric systems in catalogs of both visual and spectroscopic orbits. For this system we determine nearly identical component masses of 0.941 +/- 0.076 Msun and 0.926 +/- 0.075 Msun as well as an orbital parallax of 41.08 +/- 0.77 mas.Comment: 20 pages, 3 figures, 4 table

    Dietary Patterns and Cognitive Function among Older Community-Dwelling Adults.

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    Diet may be an important modifiable risk factor for maintenance of cognitive health in later life. This study aimed at examining associations between common dietary indices and dietary patterns defined by factor analysis and cognitive function in older community-dwelling adults. Dietary information for 1499 participants from the Rancho Bernardo Study was collected in 1988⁻1992 and used to calculate the alternate Mediterranean diet score, Alternate Healthy Eating Index (AHEI)-2010 score and factor scores derived from factor analysis of nutrients. Global cognitive function, executive function, verbal fluency and episodic memory were assessed at approximate four-year intervals from 1988⁻2016. Linear mixed models were used to examine associations between dietary patterns and cognitive trajectories. Estimates for the highest vs. lowest tertile in models adjusting for age, sex, education, energy intake, lifestyle variables and retest effect showed greater adherence to the Mediterranean score was associated with better baseline global cognitive function (β (95% CI) = 0.33 (0.11, 0.55)). The AHEI-2010 score was not significantly associated with cognitive performance. Higher loading on a plant polyunsaturated fatty acid (PUFA)/vitamin E factor was associated with better baseline global cognitive function and executive function (β = 0.22 (0.02, 0.42) and β = -7.85 (-13.20, -2.47)). A sugar/low protein factor was associated with poorer baseline cognitive function across multiple domains. Dietary patterns were not associated with cognitive decline over time. Adherence to a healthy diet with foods high in PUFA and vitamin E and a low sugar to protein ratio, as typified by a Mediterranean diet, may be beneficial for cognitive health in late life

    Hydrogenation of CO on a silica surface: an embedded cluster approach

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    The sequential addition of H atoms to CO adsorbed on a siliceous edingtonite surface is studied with an embedded cluster approach, using density functional theory for the quantum mechanical (QM) cluster and a molecular force field for the molecular mechanical (MM) cluster. With this setup, calculated QM/MM adsorption energies are in agreement with previous calculations employing periodic boundary conditions. The catalytic effect of the siliceous edingtonite (100) surface on CO hydrogenation is assessed because of its relevance to astrochemistry. While adsorption of CO on a silanol group on the hydroxylated surface did not reduce the activation energy for the reaction with a H atom, a negatively charged defect on the surface is found to reduce the gas phase barriers for the hydrogenation of both CO and H2C = O. The embedded cluster approach is shown to be a useful and flexible tool for studying reactions on (semi-)ionic surfaces and specific defects thereon. The methodology presented here could easily be applied to study reactions on silica surfaces that are of relevance to other scientific areas, such as biotoxicity of silica dust and geochemistry

    Spectral Signatures of Immature \u3cem\u3eLucilia sericata\u3c/em\u3e (Meigen) (Diptera: Calliphoridae)

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    Hyperspectral remote sensing is an innovative technology with applications in many sciences and is a non-destructive method that may offer more precise aging within development stages. Hyperspectral reflectance measurements from the anterior, midsection, and posterior of Lucilia sericata (Meigen) larvae and pupae were conducted daily from samples of the developing insects beginning at second instar. Only midsection measurements were conducted on second instar larvae due to their size, to ensure that the measurement was not of reflective surroundings. Once measured, all insects were washed with deionized water, blotted with filter paper, and re-measured. Daily age prediction during the post-feeding stage was not impacted by the unwashed insect measurements and was best predicted based on posterior measurements. The second and third instar larvae, which move about their food source, had different contributing coefficients to the functional regression model for the hyperspectral measurements of the washed compared with unwashed specimens. Although washing did not affect the daily prediction within these stages, it is still encouraged in order to decrease the effect of food source on spectral reflectance. Days within the intra-puparial period were best predicted based on anterior measurements and were not well distinguished from one another in the first few days based on midsection and posterior measurements

    Hyperspectral measurements of immature \u3cem\u3eLucilia sericata\u3c/em\u3e (Meigen) (Diptera: Calliphoridae) raised on different food substrates

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    Immature Lucilia sericata (Meigen) raised on beef liver, beef heart, pork liver and pork heart at a mean temperature of 20.6°C took a minimum of 20 days to complete development. Minimum development time differences within stages were observed between the meat types (pork/beef), but not the organ types (liver/heart). Daily hyperspectral measurements were conducted and a functional regression was completed to examine the main effects of meat and organ type on daily spectral measurements. The model examined post feeding larval spectral measurements of insects raised on beef liver alone, the effect of those raised on pork compared with those raised on beef, the effect of those raised on heart compared with those raised on liver and the interactional effect of those raised on pork heart compared with those raised on beef liver. The analyses indicated that the spectral measurements of post feeding L. sericata raised on pork and beef organs (liver and heart) are affected by the meat and organ type

    Infrared Spectroscopic Study of a Selection of AGB and Post-AGB Stars

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    We present here near-infrared spectroscopy in the H and K bands of a selection of nearly 80 stars that belong to various AGB types, namely S type, M type and SR type. This sample also includes 16 Post-AGB (PAGB) stars. From these spectra, we seek correlations between the equivalent widths of some important spectral signatures and the infrared colors that are indicative of mass loss. Repeated spectroscopic observations were made on some PAGB stars to look for spectral variations. We also analyse archival SPITZER mid-infrared spectra on a few PAGB stars to identify spectral features due to PAH molecules providing confirmation of the advanced stage of their evolution. Further, we model the SEDs of the stars (compiled from archival data) and compare circumstellar dust parameters and mass loss rates in different types. Our near-infrared spectra show that in the case of M and S type stars, the equivalent widths of the CO(3-0) band are moderately correlated with infrared colors, suggesting a possible relationship with mass loss processes. A few PAGB stars revealed short term variability in their spectra, indicating episodic mass loss: the cooler stars showed in CO first overtone bands and the hotter ones showed in HI Brackett lines. Our spectra on IRAS 19399+2312 suggest that it is a transition object. From the SPITZER spectra, there seems to be a dependence between the spectral type of the PAGB stars and the strength of the PAH features. Modelling of SEDs showed among the M and PAGB stars that the higher the mass loss rates, the higher the [K-12] colour in our sample.Comment: 14 pages; accepted in MNRAS, 200

    The UK quality and outcomes framework pay-for-performance scheme and spirometry: rewarding quality or just quantity? A cross-sectional study in Rotherham, UK

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    Background: Accurate spirometry is important in the management of COPD. The UK Quality and Outcomes Framework pay-for-performance scheme for general practitioners includes spirometry related indicators within its COPD domain. It is not known whether high achievement against QOF spirometry indicators is associated with spirometry to BTS standards. Methods: Data were obtained from the records of 3,217 patients randomly sampled from 5,649 patients with COPD in 38 general practices in Rotherham, UK. Severity of airflow obstruction was categorised by FEV1 (% predicted) according to NICE guidelines. This was compared with clinician recorded COPD severity. The proportion of patients whose spirometry met BTS standards was calculated in each practice using a random sub-sample of 761 patients. The Spearman rank correlation between practice level QOF spirometry achievement and performance against BTS spirometry standards was calculated. Results: Spirometry as assessed by clinical records was to BTS standards in 31% of cases (range at practice level 0% to 74%). The categorisation of airflow obstruction according to the most recent spirometry results did not agree well with the clinical categorisation of COPD recorded in the notes (Cohen's kappa = 0.34, 0.30 - 0.38). 12% of patients on COPD registers had FEV1 (% predicted) results recorded that did not support the diagnosis of COPD. There was no association between quality, as measured by adherence to BTS spirometry standards, and either QOF COPD9 achievement (Spearman's rho = -0.11), or QOF COPD10 achievement (rho = 0.01). Conclusion: The UK Quality and Outcomes Framework currently assesses the quantity, but not the quality of spirometry

    The axial N to Delta transition form factors from Lattice QCD

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    We evaluate the N to Delta axial transition form factors in lattice QCD in the quenched theory, with two degenerate flavors of dynamical Wilson fermions and using domain wall valence fermions with staggered sea quark configurations. We predict the ratio C5A(q2)/C3V(q2)C_5^A(q^2)/C_3^V(q^2) relevant to the parity violating asymmetry and check the validity of the off-diagonal Goldberger-Treiman relation.Comment: Version as accepted for publication, Fig.2 replaced, Normalization factor corrected in Fig.4; 4 pages, 5 figure

    Protein Expression in Cold Acclimating and Freezing Tolerant Grape Cane Tissues

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    The continental climate in Iowa is important when selecting grape cultivars that are tolerant of low-temperature stresses. Many coldregulated (COR) proteins respond to freezing stress, and are able to protect cellular membranes from cold-induced dehydration damage. It is unknown which proteins are important for cultivars to withstand extreme temperature fluctuations and low temperatures that can injure over-wintering canes. The objective of this investigation is to observe the ability of two grape cultivars to survive extreme temperature fluctuations during coldacclimation, mid winter, and deacclimation. Experiments will be conducted to determine and compare changes in proteins during cold acclimation and deacclimation in canes for Frontenac and Seyval blanc grape cultivars
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