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Objectives: The purpose of this investigation was to use an excised human larynx to substantiate physical mechanisms of sustained vocal fold oscillation over a variety of phonatory conditions. During sustained, flow-induced oscillation, dynamical data was collected from the medial surface of the vocal fold. The method of Empirical Eigenfunctions was used to analyze the data and to probe physical mechanisms of sustained oscillation.Methods: Thirty microsutures were mounted on the medial margin of a human vocal fold. Across five distinct phonatory conditions, the vocal fold was set into oscillation and imaged with a high-speed digital imaging system. The position coordinates of the sutures were extracted from the images and converted into physical coordinates. Empirical Eigenfunctions were computed from the time-varying physical coordinates, and mechanisms of sustained oscillation were explored.Results: Using the method of Empirical Eigenfunctions, physical mechanisms of sustained vocal fold oscillation were substantiated. In particular, the essential dynamics of vocal fold vibration were captured by two dominant Empirical Eigenfunctions. The largest Eigenfunction primarily captured the alternating convergent/divergent shape of the medial surface of the vocal fold, while the second largest Eigenfunction primarily captured the lateral vibrations of the vocal fold.Conclusions: The hemi-larynx setup yielded a view of the medial surface of the vocal folds, revealing the tissue vibrations which produced sound. Through the use of Empirical Eigenfunctions, the underlying modes of vibration were computed, disclosing physical mechanisms of sustained vocal fold oscillation. The investigation substantiated previous theoretical analyses and yielded significant data to help evaluate and refine computational models of vocal fold vibration. [ABSTRACT FROM AUTHOR] more...

Aims. We investigate the nature of the long-period radial velocity variations in Tau first reported over 20 yr ago. Methods. We analyzed precise stellar radial velocity measurements for Tau spanning over 30 yr. An examination of the H and Ca II λ8662 spectral lines, and Hipparcos photometry was also done to help discern the nature of the long-period radial velocity variations. Results. Our radial velocity data show that the long-period, low amplitude radial velocity variations are long-lived and coherent. Furthermore, H equivalent width measurements and Hipparcos photometry show no significant variations with this period. Another investigation of this star established that there was no variability in the spectral line shapes with the radial velocity period. An orbital solution results in a period of P = 628.96 ± 0.90 d, eccentricity, e = 0:10±0:05, and a radial velocity amplitude, K = 142:1±7:2 ms-1. Evolutionary tracks yield a stellar mass of 1.13 ± 0.11 M, which corresponds to a minimum companion mass of 6.47 ± 0.53 MJup with an orbital semi-major axis of a = 1:46 ± 0:27 AU. After removing the orbital motion of the companion, an additional period of ≈520 d is found in the radial velocity data, but only in some time spans. A similar period is found in the variations in the equivalent width of H and Ca II. Variations at one-third of this period are also found in the spectral line bisector measurements. The 520 d period is interpreted as the rotation modulation by stellar surface structure. Its presence, however, may not be long-lived, and it only appears in epochs of the radial velocity data separated by ∼10 yr. This might be due to an activity cycle. Conclusions. The data presented here provide further evidence of a planetary companion to Tau, as well as activity-related radial velocity variations. [ABSTRACT FROM AUTHOR] more...

We analysed an extended time series of high-resolution spectra of the d Sct star WASP-33 with the aim to determine the effect of its planet WASP-33b. We found ten frequencies in the measured radial velocities. Three of them we can attribute to previously observed photometric oscillations due to non-radial pulsations. One frequency exactly agrees with the orbital period of the planet. The semiamplitude of the corresponding variation is 304 ± 20 ms-1. This finding allows us to give a new estimate of the mass of WASP-33b of 2.1 ± 0.2 Jupiter masses. Its mean density probably is at least 0.6 g cm-3, a value that can be expected for a planet of its mass that orbits an A-type star in 1.22 d. [ABSTRACT FROM AUTHOR] more...

BackgroundThe rising prevalence of nonalcoholic fatty liver disease (NAFLD) and the more aggressive subtype, nonalcoholic steatohepatitis (NASH), is a global public health concern. Left untreated, NAFLD/NASH can lead to cirrhosis, liver failure, and death. The current standard for diagnosing and staging liver disease is a liver biopsy, which is costly, invasive, and carries risk for the patient. Therefore, there is a growing need for a reliable, feasible, and cost-effective, noninvasive diagnostic tool for these conditions. LiverMultiScan is one such promising tool that uses multi-parametric magnetic resonance imaging (mpMRI) to characterize liver tissue and to aid in the diagnosis and monitoring of liver diseases of various etiologies. ObjectiveThe primary objective of this trial (RADIcAL1) is to evaluate the cost-effectiveness of the introduction of LiverMultiScan as a standardized diagnostic test for liver disease in comparison to standard care for NAFLD, in different EU territories. MethodsRADIcAL1 is a multi-center randomized control trial with 2 arms conducted in 4 European territories (13 sites, from across Germany, Netherlands, Portugal, and the United Kingdom). In total, 1072 adult patients with suspected fatty liver disease will be randomized to be treated according to the result of the mpMRI in the intervention arm, so that further diagnostic evaluation is recommended only when values for metrics of liver fat or fibro-inflammation are elevated. Patients in the control arm will be treated as per center guidelines for standard of care. The primary outcome for this trial is to compare the difference in the proportion of patients with suspected NAFLD incurring liver-related hospital consultations or liver biopsies between the study arms, from the date of randomization to the end of the study follow-up. Secondary outcomes include patient feedback from a patient satisfaction questionnaire, at baseline and all follow-up visits to the end of the study, and time, from randomization to diagnosis by the physician, as recorded at the final follow-up visit. ResultsThis trial is currently open for recruitment. The anticipated completion date for the study is December 2020. ConclusionsThis randomized controlled trial will provide the evidence to accelerate decision making regarding the inclusion of mpMRI-based tools in existing NAFLD/NASH clinical care. RADIcAL1 is among the first and largest European health economic studies of imaging technologies for fatty liver disease. Strengths of the trial include a high-quality research design and an in-depth assessment of the implementation of the cost-effectiveness of the mpMRI diagnostic. If effective, the trial may highlight the health economic burden on tertiary-referral hepatology clinics imposed by unnecessary consultations and invasive diagnostic investigations, and demonstrate that including LiverMultiScan as a NAFLD diagnostic test may be cost-effective compared to liver-related hospital consultations or liver biopsies. Trial RegistrationClinicalTrials.gov NCT03289897 https://clinicaltrials.gov/ct2/show/NCT03289897 International Registered Report Identifier (IRRID)DERR1-10.2196/19189 more...

Aims. Our aim is to use precise radial velocity measurements and photometric data to derive the frequency spacing of the p-mode oscillation spectrum of the planet-hosting star β Gem. This spacing along with the interferometric radius for this star can then be used to derive an accurate stellar mass. Methods. We use a long time series of over 60 h of precise stellar radial velocity measurements of β Gem taken with an iodine absorption cell at the echelle spectrograph mounted on the 2 m Alfred Jensch Telescope. We also present complementary photometric data for this star taken with the MOST microsatellite spanning 3.6 d. A Fourier analysis is used to derive the frequencies that are present in each data set. Results. The Fourier analysis of the radial velocity data reveals the presence of up to 17 significant pulsation modes in the frequency interval 10-250 μHz. Most of these fall on a grid of equally-spaced frequencies having a separation of 7.14 ± 0.12 μHz. An analysis of 3.6 days of high precision photometry taken with the MOST space telescopes shows the presence of up to 16 modes, six of which are consistent with modes found in the spectral (radial velocity) data. This frequency spacing is consistent with high overtone radial pulsations; however, until the pulsation modes are identified we cannot be sure if some of these are nonradial modes or even mixed modes. The radial velocity frequency spacing along with angular diameter measurements of β Gem via interferometry results in a stellar mass of M = 1.91 ± 0.09 M⊙. This value confirms the intermediate mass of the star determined using stellar evolutionary tracks. Conclusions.β Gem is confirmed to be an intermediate mass star. Stellar pulsations in giant stars along with interferometric radius measurements can provide accurate determinations of the stellar mass of planet hosting giant stars. These can also be used to calibrate stellar evolutionary tracks. [ABSTRACT FROM AUTHOR] more...

Voice quality is strongly dependent on vocal fold dynamics, which in turn are dependent on lung pressure and vocal fold biomechanics. Numerical and physical models are often used to investigate the interactions of these different subsystems. However, the utility of numerical and physical models is limited unless appropriately validated with data from physiological models. Hence a method that enables analysis of local vocal fold deformations along the entire surface is presented. In static tensile tests, forces are applied to distinctive working points being located in cover and muscle, respectively, so that specific layer properties can be investigated. The forces are directed vertically upward and are applied along or above the vocal fold edge. The resulting deformations are analyzed using multiple perspectives and three-dimensional reconstruction. Deformation characteristics of four human vocal folds were investigated. Preliminary results showed two phases of deformation: a range with a small slope for small deformations fading into a significant nonlinear deformation trend with a high slope. An increase of tissue stiffness from posterior to anterior was detected. This trend is more significant for muscle and in the mid-anterior half of the vocal fold. [ABSTRACT FROM AUTHOR] more...

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In da Silva et al. (2005) is presented the detailed spectroscopic analysis of 60 evolved stars, which were previously studied for accurate radial velocity variations (Setiawan et al. 2003). The observations were made with FEROS and the 1.52m ESO telescope of La Silla, partially in the ESO-Observatório Nacional (Brazil) agreement. The main goal of this study is to determine precise atmospheric fundamental data (Teff, log g, [Fe/H] and micro-turbulence velocity) to derive ages and masses of the stars, trying to link them to the detected radial velocity variabilities. Here, due the short space at our disposal, we discuss only the effective temperature determination, comparing the values obtained from the excitation equilibrium of FeI and from (V-K) index with those from (B-V). [ABSTRACT FROM PUBLISHER] more...