Masses, Oxygen and Carbon abundances in CHEPS dwarf stars

Reproduced with permission from Astronomy & Astrophysics. © 2019 ESOContext. We report the results from the determination of stellar masses, carbon, and oxygen abundances in the atmospheres of 107 stars from the Calan-Hertfordshire Extrasolar Planet Search (CHEPS) programme. Our stars are drawn from a population with a significantly super-solar metallicity. At least 10 of these stars are known to host orbiting planets. Aims. In this work, we set out to understand the behaviour of carbon and oxygen abundance in stars with different spectral classes, metallicities, and V sin i within the metal-rich stellar population. Methods. Masses of these stars were determined using data from Gaia DR2. Oxygen and carbon abundances were determined by fitting the absorption lines. We determined oxygen abundances with fits to the 6300.304 Å O I line, and we used 3 lines of the C I atom and 12 lines of the C 2 molecule for the determination of carbon abundances. Results. We determine masses and abundances of 107 CHEPS stars. There is no evidence that the [C/O] ratio depends on V sin i or the mass of the star within our constrained range of masses, i.e. 0.82 5 km s -1) are massive stars.Peer reviewedFinal Published versio

Asthma in Vermont Dairy Farmers

Introduction. Although 5.4% of the Vermont population participates in agriculture as an occupation, little data exists on the prevalence of asthma in Vermont dairy farmers, due to inadequate sample sizes. Previous studies have shown dairy farmers are at risk of respiratory illness due to unique exposures intrinsic to their occupation. We conducted a study to assess the prevalence of asthma in dairy farmers in Vermont, to understand rates among this population and potential occupational risks.Methods. We distributed a paper survey modeled after previously-validated surveys, such as the BRFSS, to farmers at Vermont Farmer Bureau meetings, farmers markets, and individual farmers through Cabot Creamery. Out of 309 distributed surveys, we received 176 completed surveys for a response rate of 57%.Results. Self-reported asthma rate in dairy farmers was 21% (22% in dairy only farmers), with 90% of these cases reported as confirmed by a doctor. Of non-dairy farmers, 11% self-reported experiencing asthma. Farming activities associated with exacerbation of asthma symptoms were milking, prepping or cleaning bedding, and haying. 31% of dairy-only farmers reported symptom exacerbations due to these occupational triggers.Conclusions. The prevalence of asthma in Vermont dairy farmers is one of the highest reported rates in any Vermont occupation. Our data suggest that certain occupational exposures may increase risk of asthma and warrant further study; certain farming practices were associated with exacerbation of respiratory symptoms in farmers diagnosed with asthma. These findings and further research can assist in development of health care and preventive health measures for farmers.https://scholarworks.uvm.edu/comphp_gallery/1238/thumbnail.jp

Extended Kalman Filter for Photographic Data from Impact Acceleration Tests

This paper presents the development of an Extended Kalman Filter (EKF) that optimally processes photographic data collected during short-duration impact acceleration tests. The system is modeled by a non-linear state-space representation using quaternions for rotational kinematics. Three cameras are used to photograph up to 14 fiducials mounted on a plate attached to the subject\u27s mouth. The filter yields the history of the rotational and translational kinematics of the origin of the mouth plate. Results from the EKF and analysis of the estimation error are presented

Acoustical Boundary Location through Texture Analysis of Multibeam Bathymetric Sonar Data

Texture analysis is performed on multibeam sonar signal returns discriminated angularity by beamforming. A collection of fourteen texture features are computed via co-occurrence matrices and data reduction is then performed using a principal components transformation. Acoustical boundaries (boundaries between regions with homogeneous acoustical properties) are evident from the features. Results indicate that seafloor bottom characteristics can be extracted from these texture features

Quantitative analysis of the V838 Monocerotis spectrum

We present the determination of the effective temperature, iron abundance, and microturbulent velocities for the pseudophotosphere of V838 Mon observed on February 25, March 2 and 26, 2002. Physical parameters of the line forming region were obtained in the framework of a self-consistent approach using fits of synthetic spectra to observed spectra in the wavelength range 5500–6700 Å. We obtained the values of Teff 5330±150 K, 5540±150 K, and 4960±150 K for February 25, March 2, and March 26, 2002, respectively. The iron abundance logN(Fe) = −4.7 does not appear to change in the atmosphere of V838 Mon from February 25 to March 26, 2002