56 research outputs found
Pisces, Characiformes, Characidae, Glandulocaudinae, <i>Mimagoniates barberi</i> Regan, 1907: First Argentinean distribution record.
The current note reports the presence of Mimagoniates barberi at northeastern Argentina. This record representsthe southernmost limit for this species and the first country record of the genus
High-precision analysis of binary stars with planets. I. Searching for condensation temperature trends in the HD 106515 system
We explore the probable chemical signature of planet formation in the
remarkable binary system HD 106515. The A star hosts a massive long-period
planet with 9 MJup detected by radial velocity. We also refine stellar and
planetary parameters by using non-solar-scaled opacities when modeling the
stars. Methods. We carried out a simultaneous determination of stellar
parameters and abundances, by applying for the first time non-solar-scaled
opacities in this binary system, in order to reach the highest possible
precision. Results. The stars A and B in the binary system HD 106515 do not
seem to be depleted in refractory elements, which is different when comparing
the Sun with solar-twins. Then, the terrestrial planet formation would have
been less efficient in the stars of this binary system. Together with HD
80606/7, this is the second binary system which does not seem to present a
(terrestrial) signature of planet formation, and hosting both systems an
eccentric giant planet. This is in agreement with numerical simulations, where
the early dynamical evolution of eccentric giant planets clear out most of the
possible terrestrial planets in the inner zone. We refined the stellar mass,
radius and age for both stars and found a notable difference of 78% in R
compared to previous works. We also refined the planet mass to mp sini = 9.08
+/- 0.20 MJup, which differs by 6% compared with literature. In addition, we
showed that the non-solar-scaled solution is not compatible with the classical
solar-scaled method, and some abundance differences are comparable to NLTE or
GCE effects specially when using the Sun as reference. Then, we encourage the
use of non-solar-scaled opacities in high-precision studies such as the
detection of Tc trends.[abridged]Comment: 9 pages, 10 figures, A&A accepted. arXiv admin note: text overlap
with arXiv:1507.0812
KELT-17: a chemically peculiar Am star and a hot-Jupiter planet
Context. The detection of planets orbiting chemically peculiar stars is very
scarcely known in the literature. Aims. To determine the detailed chemical
composition of the remarkable planet host star KELT-17. This object hosts a
hot-Jupiter planet with 1.31 MJup detected by transits, being one of the more
massive and rapidly rotating planet hosts to date. We aimed to derive a
complete chemical pattern for this star, in order to compare it with those of
chemically peculiar stars. Methods. We carried out a detailed abundance
determination in the planet host star KELT-17 via spectral synthesis. Stellar
parameters were estimated iteratively by fitting Balmer line profiles and
imposing the Fe ionization balance, using the program SYNTHE together with
plane-parallel ATLAS12 model atmospheres. Specific opacities for an arbitrary
composition and microturbulence velocity vmicro were calculated through the
Opacity Sampling (OS) method. The abundances were determined iteratively by
fitting synthetic spectra to metallic lines of 16 different chemical species
using the program SYNTHE. The complete chemical pattern of KELT-17 was compared
to the recently published average pattern of Am stars. We estimated the stellar
radius by two methods: a) comparing the synthetic spectral energy distribution
with the available photometric data and the Gaia parallax, and b) using a
Bayesian estimation of stellar parameters using stellar isochrones. Results. We
found overabundances of Ti, Cr, Mn, Fe, Ni, Zn, Sr, Y, Zr, and Ba, together
with subsolar values of Ca and Sc. Notably, the chemical pattern agrees with
those recently published of Am stars, being then KELT-17 the first exoplanet
host whose complete chemical pattern is unambiguously identified with this
class. The stellar radius derived by two different methods agrees to each other
and with those previously obtained in the literature.Comment: 5 pages, 8 figures, 2 tables, A&A accepte
Interplay of glycemic index, glycemic load, and dietary antioxidant capacity with insulin resistance in subjects with a cardiometabolic risk profile
Background: Dietary total antioxidant capacity (TAC), glycemic index (GI), and glycemic
load (GL) are accepted indicators of diet quality, which have an effect on dietâdisease relationships.
The aim of this study was to evaluate potential associations of dietary TAC, GI, and GL with variables
related to nutritive status and insulin resistance (IR) risk in cardiometabolic subjects. Methods: A total
of 112 overweight or obese adults (age: 50.8 ± 9 years old) were included in the trial. Dietary intake
was assessed by a validated 137-item food frequency questionnaire (FFQ), which was also used
to calculate the dietary TAC, GI, and GL. Anthropometrics, blood pressure, body composition by
dual-energy X-ray absorptiometry (DXA), glycemic and lipid profiles, C-reactive protein (CRP),
as well as fatty liver quantification by magnetic resonance imaging (MRI) were assessed. Results:
Subjects with higher values of TAC had significantly lower circulating insulin concentration and
homeostatic model assessment of insulin resistance (HOMA-IR). Participants with higher values of
HOMA-IR showed significantly higher GI and GL. Correlation analyses showed relevant inverse
associations of GI and GL with TAC. A regression model evidenced a relationship of HOMA-IR
with TAC, GI, and GL. Conclusion: This data reinforces the concept that dietary TAC, GI, and GL
are potential markers of diet quality, which have an impact on the susceptible population with a
cardiometabolic risk profile
Predictive value of serum ferritin in combination with alanine aminotransferase and glucose levels for noninvasive assessment of NAFLD: Fatty liver in obesity (FLiO) study
The identification of affordable noninvasive biomarkers for the diagnosis and characterization of nonalcoholic fatty liver disease (NAFLD) is a major challenge for the research community. This study aimed to explore the usefulness of ferritin as a proxy biomarker of NAFLD condition, alone or in combination with other routine biochemical parameters. Subjects with overweight/obesity and ultrasound-confirmed liver steatosis (n = 112) from the Fatty Liver in Obesity (FLiO) study were assessed. The hepatic evaluation considered magnetic resonance imaging, ultrasonography, and credited routine blood liver biomarkers. Anthropometry and body composition, dietary intake (by means of a validated 137-item food frequency questionnaire), and specific biochemical markers were also determined. Serum ferritin levels were analyzed using a chemiluminescent microparticle immunoassay kit. Lower serum ferritin concentrations were associated with general better liver health and nutritional status. The evaluation of ferritin as a surrogate of liver damage by means of quantile regression analyses showed a positive association with alanine aminotransferase (ALT) (ÎČ = 19.21; p †0.001), liver fat content (ÎČ = 8.70; p = 0.008), and hepatic iron (ÎČ = 3.76; p †0.001), after adjusting for potential confounders. In receiver operating characteristic (ROC) analyses, the panel combination of blood ferritin, glucose, and ALT showed the best prediction for liver fat mass (area under the curve (AUC) 0.82). A combination of ferritin and ALT showed the higher predictive ability for estimating liver iron content (AUC 0.73). This investigation demonstrated the association of serum ferritin with liver health as well as with glucose and lipid metabolism markers in subjects with NAFLD. Current findings led to the identification of ferritin as a potential noninvasive predictive biomarker of NAFLD, whose surrogate value increased when combined with other routine biochemical measurements (glucose/ALT)
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