The analysis of brain signal variability is a promising approach to understand pathological brain function related to chronic pain. This study investigates whether blood-oxygen-level–dependent signal ...variability (BOLDSV) in specific frequency bands is altered in temporomandibular disorder (TMD) and correlated to its clinical features. Twelve patients with chronic myofascial TMD and 24 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging. The BOLDSV was measured as the standard deviation of the BOLD time series at each voxel and compared between groups. We also examined the potential relationship between the BOLDSV and the catechol-O-methyltransferase (COMT) Val158Met polymorphism. We assessed sensory-discriminative pain in the craniofacial region, pain sensitivity to sustained masseteric pain challenge, and TMD pain frequency for clinical correlation. Patients displayed reduced BOLDSV in the dorsolateral prefrontal cortex (dlPFC) as compared with HC in all frequency bands. In the slow-3 band, patients also showed reduced BOLDSV in the medial dorsal thalamus, primary motor cortex (M1), and primary somatosensory cortex (S1) and heightened BOLDSV in the temporal pole. Notably, we found a significant correlation between lower BOLDSV (slow-3) in the orofacial M1/S1 regions and higher clinical pain (intensity/area) and higher sensitivity of the masseter muscle pain. Moreover, lower BOLDSV (slow-3) in the dlPFC and ventrolateral PFC was associated with a higher TMD pain frequency. Participants who had the COMT 158Met substitution exhibited lower BOLDSV in the dlPFC and higher BOLDSV in the temporal pole as compared with participants without the COMT 158Met substitution. An increasing number of Met alleles was associated with lower dlPFC and greater temporal pole BOLDSV in both HC and TMD groups. Together, we demonstrated that chronic TMD patients exhibit aberrant BOLDSV in the top-down pain modulatory and sensorimotor circuits associated with their pain frequency and severity. COMT Val158Met polymorphism might affect clinical symptoms in association with regional brain signal variability, specifically involved in cognitive and emotional regulation of pain.
Context. Binaries in double-lined spectroscopic systems (SB2) provide a homogeneous set of stars. Differences of parameters, such as age or initial conditions, which otherwise would have strong ...impact on the stellar evolution, can be neglected. The observed differences are determined by the difference in stellar mass between the two components. The mass ratio can be determined with much higher accuracy than the actual stellar mass. Aim. In this work, we aim to study the eccentric binary system KIC 9163796, whose two components are very close in mass and both are low-luminosity red-giant stars. Methods. We analysed four years of Kepler space photometry and we obtained high-resolution spectroscopy with the Hermes instrument. The orbital elements and the spectra of both components were determined using spectral disentangling methods. The effective temperatures, and metallicities were extracted from disentangled spectra of the two stars. Mass and radius of the primary were determined through asteroseismology. The surface rotation period of the primary is determined from the Kepler light curve. From representative theoretical models of the star, we derived the internal rotational gradient, while for a grid of models, the measured lithium abundance is compared with theoretical predictions. Results. From seismology the primary of KIC 9163796 is a star of 1.39 ± 0.06M⊙, while the spectroscopic mass ratio between both components can be determined with much higher precision by spectral disentangling to be 1.015 ± 0.005. With such mass and a difference in effective temperature of 600 K from spectroscopy, the secondary and primary are, respectively, in the early and advanced stage of the first dredge-up event on the red-giant branch. The period of the primary’s surface rotation resembles the orbital period within ten days. The radial rotational gradient between the surface and core in KIC 9163796 is found to be $6.9^{+2.0}_{-1.0}$ 6.9−1.0+2.0 6.9−1.0+2.0 . This is a low value but not exceptional if compared to the sample of typical single field stars. The seismic average of the envelope’s rotation agrees with the surface rotation rate. The lithium’abundance is in agreement with quasi rigidly rotating models. Conclusions. The agreement between the surface rotation with the seismic result indicates that the full convective envelope is rotating quasi-rigidly. The models of the lithium abundance are compatible with a rigid rotation in the radiative zone during the main sequence. Because of the many constraints offered by oscillating stars in binary systems, such objects are important test beds of stellar evolution.
Context.
Brown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass ...measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint for a spectroscopic follow-up.
Aims.
Microlensing provides an alternative tool for the discovery and investigation of such faint systems. Here, we present an analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is caused by a binary system composed of a brown dwarf orbiting a red dwarf.
Methods.
Thanks to extensive ground observations and the availability of space observations from
Spitzer,
it has been possible to obtain accurate estimates of all microlensing parameters, including the parallax, source radius, and orbital motion of the binary lens.
Results.
Following an accurate modeling process, we found that the lens is composed of a red dwarf with a mass of
M
1
= 0.149 ± 0.010
M
⊙
and a brown dwarf with a mass of
M
2
= 0.0463 ± 0.0031
M
⊙
at a projected separation of
a
⊥
= 0.585 au. The system has a peculiar velocity that is typical of old metal-poor populations in the thick disk. A percent-level precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become more common in the future thanks to the
Roman
space telescope.
Solar twins have been a focus of attention for more than a decade, because their structure is extremely close to that of the Sun. Today, thanks to high-precision spectrometers, it is possible to use ...asteroseismology to probe their interiors. Our goal is to use time series obtained from the HARPS spectrometer to extract the oscillation frequencies of 18 Sco, the brightest solar twin. We used the tools of spectral analysis to estimate these quantities. We estimate 52 frequencies using an MCMC algorithm. After examination of their probability densities and comparison with results from direct MAP optimization, we obtain a minimal set of 21 reliable modes. The identification of each pulsation mode is straightforwardly accomplished by comparing to the well-established solar pulsation modes. We also derived some basic seismic indicators using these values. These results offer a good basis to start a detailed seismic analysis of 18 Sco using stellar models.
Hepatitis E virus (HEV) genotype 3 is the most prevalent HEV genotype in Europe causing mostly asymptomatic infections in humans, but can also sporadically cause severe acute hepatitis, chronic liver ...disease, chronic hepatitis in immunocompromised patients and extra‐hepatic manifestations. Although much is today known about the swine reservoir, no information is available on the occurrence of HEV from widely distributed deer species in Portugal. Here, we investigated the presence and characterized HEV in free‐living deer in Portugal by screening stools from red deer (Cervus elaphus) (n = 95) and fallow deer (Dama dama) (n = 35) for HEV by a broad‐spectrum nested RT‐PCR, followed by sequencing and phylogenetic analysis. Two red deer females, sampled in central Portugal, showed to be shedding HEV (2.1%; 95% confidence interval: 0.58–7.35). Sequencing and genetic characterization showed that these two deer HEV sequences were 98.96% identical to each other, being both of HEV genotype 3 subgenotype 3e. The increasing numbers and distribution of deer in Portugal and the zoonotic features of the circulating HEV genotype 3 subgenotype 3e highlights the importance of continued surveillance directed to food‐borne diseases, especially those involving wild animals and deer in particular.
Determination of fundamental parameters of stars impacts all fields of astrophysics, from galaxy evolution to constraining the internal structure of exoplanets. This paper presents a detailed ...spectroscopic analysis of Barnard's star that compares an exceptionally high-quality (an average signal-to-noise ratio of \(\sim\)1000 in the entire domain), high-resolution NIR spectrum taken with CFHT/SPIRou to PHOENIX-ACES stellar atmosphere models. The observed spectrum shows thousands of lines not identified in the models with a similar large number of lines present in the model but not in the observed data. We also identify several other caveats such as continuum mismatch, unresolved contamination and spectral lines significantly shifted from their expected wavelengths, all of these can be a source of bias for abundance determination. Out of \(>10^4\) observed lines in the NIR that could be used for chemical spectroscopy, we identify a short list of a few hundred lines that are reliable. We present a novel method for determining the effective temperature and overall metallicity of slowly-rotating M dwarfs that uses several groups of lines as opposed to bulk spectral fitting methods. With this method, we infer \(T_{eff}\) = 3231 \(\pm\) 21 K for Barnard's star, consistent with the value of 3238 \(\pm\) 11 K inferred from the interferometric method. We also provide abundance measurements of 15 different elements for Barnard's star, including the abundances of four elements (K, O, Y, Th) never reported before for this star. This work emphasizes the need to improve current atmosphere models to fully exploit the NIR domain for chemical spectroscopy analysis.
Abstract Objective The aim of the present study was to assess the influence of diet in tooth erosion presence in children and adolescents by meta-analysis and meta-regression. Data Two reviewers ...independently performed the selection process and the quality of studies was assessed. Sources Studies published until May 2014 were identified in electronic databases: Pubmed, EBSHost, Scopus, Science direct, Web of Science and Scielo, using keywords. Study selection Criteria used included: observational studies, tooth erosion and diet, subject age range 8–19 years old, permanent dentition and index. Meta-analysis was performed and in case of heterogeneity a random-effects model was used. Thirteen studies that fulfilled the inclusion criteria were selected. Higher consumption of carbonated drinks ( p = 0.001) or acid snacks/sweets ( p = 0.01 and for acid fruit juices ( p = 0.03)) increased the odds for tooth erosion, while higher intake of milk ( p = 0.028) and yogurt ( p = 0.002) reduced the erosion occurrence. Heterogeneity was observed in soft drinks, confectionary and snacks and acidic fruit juices models. Methodological issues regarding the questionnaires administration and the inclusion of other variables, such as food groups and tooth brushing, explained partially the heterogeneity observed. Conclusions Some dietary components (carbonated drinks, acid snacks/sweets and natural acidic fruits juice) increased erosion occurrence while milk and yogurt had a protective effect. Methods to assess diet could influence the homogeneity of the studies and should be considered during the study design. Clinical significance The method to assess diet should be carefully considered and well conducted as part of the clinical assessment of tooth erosion, since diet could influence the occurrence of tooth erosion.
Context. The object HD 43587Aa is a G0V star observed during the 145-day LRa03 run of the COnvection, ROtation and planetary Transits space mission (CoRoT), for which complementary High Accuracy ...Radial velocity Planet Searcher (HARPS) spectra with S/N > 300 were also obtained. Its visual magnitude is 5.71, and its effective temperature is close to 5950 K. It has a known companion in a highly eccentric orbit and is also coupled with two more distant companions. Aims. We undertake a preliminary investigation of the internal structure of HD 43587Aa. Methods. We carried out a seismic analysis of the star, using maximum likelihood estimators and Markov chain Monte Carlo methods. Results. We established the first table of the eigenmode frequencies, widths, and heights for HD 43587Aa. The star appears to have a mass and a radius slightly larger than the Sun, and is slightly older (5.6 Gyr). Two scenarios are suggested for the geometry of the star: either its inclination angle is very low, or the rotation velocity of the star is very low. Conclusions. A more detailed study of the rotation and of the magnetic and chromospheric activity for this star is needed, and will be the subject of a further study. New high resolution spectrometric observations should be performed for at least several months in duration.
Context. Lithium and beryllium are destroyed at different temperatures in stellar interiors. As such, their relative abundances offer excellent probes of the nature and extent of mixing processes ...within and below the convection zone. Aims. We determine Be abundances for a sample of eight solar twins for which Li abundances have previously been determined. The analyzed solar twins span a very wide range of age, 0.5–8.2 Gyr, which enables us to study secular evolution of Li and Be depletion. Methods. We gathered high-quality UVES/VLT spectra and obtained Be abundances by spectral synthesis of the Be ii 313 nm doublet. Results. The derived beryllium abundances exhibit no significant variation with age. The more fragile Li, however, exhibits a monotonically decreasing abundance with increasing age. Therefore, relatively shallow extra mixing below the convection zone is necessary to simultaneously account for the observed Li and Be behavior in the Sun and solar twins.
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