To propose a simplified tool to recognize subjects with a moderate risk to develop type 2 diabetes mellitus (Type 2 DM): this method would take into account only variables from metabolic syndrome ...definitions which are cheaply assessable. A total of 3,003 employees without diabetes in Italy who attended one annual health examination between 2009 and 2012 were enrolled in this cross-sectional study. A questionnaire was administered along with the annual health examination to record personal and familiar anamnesis. To identify Type 2 DM-prone individuals, the diabetes predictive model by Stern MP et al. was used. Then a multiple logistic regression model was developed using the predicted probability 20 %+ of developing Type 2 DM as the outcome variable and a panel of easily measurable continuous baseline characteristics as explanatory variables (waist circumference, WC; body mass index, BMI; and systolic blood pressure, SBP). The optimism-adjusted area under the curve of the proposed model receiver-operating characteristic (ROC) is 0.90. The effects of the explanatory variables on the presumed Type 2 DM risk are summarized by the following adjusted odds ratio values: 2.65 for SBP (
P
< 0.001), 2.01 for WC (
P
= 0.04) and 4.64 for BMI (
P
< 0.001). The satisfactory ROC of the proposed model suggests the importance of simple assessments in the prognostic information on Type 2 DM risk. Such ease of use may be particularly relevant in populations facing the transition from traditional to industrial food who do not have a sophisticated health service yet.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
NICS (the Near Infrared Camera Spectrometer) is a cooled near-infrared camera-spectrometer that has been developed by the Arcetri Infrared Group at the Arcetri Astrophysical Observatory, in ...collaboration with the CAISMI-CNR for the TNG (the Italian National Telescope Galileo at La Palma, Canary Islands, Spain). As NICS is in its scientific commissioning phase, we report its observing capabilities in the near-infrared bands at the TNG, along with the measured performance and the limiting magnitudes. We also describe some technical details of the project, such as cryogenics, mechanics, and the system which executes data acquisition and control, along with the related software.
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The GAPS Programme at TNG Carleo, I.; Malavolta, L.; Lanza, A. F. ...
Astronomy and astrophysics (Berlin),
06/2020, Volume:
638
Journal Article
Peer reviewed
Open access
Context.
The existence of hot Jupiters is still not well understood. Two main channels are thought to be responsible for their current location: a smooth planet migration through the protoplanetary ...disk or the circularization of an initial highly eccentric orbit by tidal dissipation leading to a strong decrease in the semimajor axis. Different formation scenarios result in different observable effects, such as orbital parameters (obliquity and eccentricity) or frequency of planets at different stellar ages.
Aims.
In the context of the GAPS Young Objects project, we are carrying out a radial velocity survey with the aim of searching and characterizing young hot-Jupiter planets. Our purpose is to put constraints on evolutionary models and establish statistical properties, such as the frequency of these planets from a homogeneous sample.
Methods.
Since young stars are in general magnetically very active, we performed multi-band (visible and near-infrared) spectroscopy with simultaneous GIANO-B + HARPS-N (GIARPS) observing mode at TNG. This helps in dealing with stellar activity and distinguishing the nature of radial velocity variations: stellar activity will introduce a wavelength-dependent radial velocity amplitude, whereas a Keplerian signal is achromatic. As a pilot study, we present here the cases of two known hot Jupiters orbiting young stars: HD 285507 b and AD Leo b.
Results.
Our analysis of simultaneous high-precision GIARPS spectroscopic data confirms the Keplerian nature of the variation in the HD 285507 radial velocities and refines the orbital parameters of the hot Jupiter, obtaining an eccentricity consistent with a circular orbit. Instead, our analysis does not confirm the signal previously attributed to a planet orbiting AD Leo. This demonstrates the power of the multi-band spectroscopic technique when observing active stars.
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Context.
Stellar activity is currently challenging the detection of young planets via the radial velocity (RV) technique.
Aims.
We attempt to definitively discriminate the nature of the RV variations ...for the young active K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent results on the existence of a substellar companion.
Methods.
We compare VIS data with high precision RVs in the near-infrared (NIR) range by using the GIANO–B and IGRINS spectrographs. In addition, we present for the first time simultaneous VIS-NIR observations obtained with GIARPS (GIANO–B and HARPS–N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV amplitude does not change at different wavelengths, while stellar activity induces wavelength-dependent RV variations, which are significantly reduced in the NIR range with respect to the VIS.
Results.
The NIR radial velocity measurements from GIANO–B and IGRINS show an average amplitude of about one quarter with respect to previously published VIS data, as expected when the RV jitter is due to stellar activity. Coeval multi-band photometry surprisingly shows larger amplitudes in the NIR range, explainable with a mixture of cool and hot spots in the same active region.
Conclusions.
In this work, the claimed massive planet around BD+20 1790 is ruled out by our data. We exploited the crucial role of multi-wavelength spectroscopy when observing young active stars: thanks to facilities like GIARPS that provide simultaneous observations, this method can reach its maximum potential.
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Aims. Determining the intensity of lines and continuum airglow emission in the H-band is important for the design of faint-object infrared spectrographs. Existing spectra at low or medium resolution ...cannot disentangle the true sky continuum from instrumental effects (e.g. diffuse light in the wings of strong lines). We aim to obtain, for the first time, a high-resolution infrared spectrum that is deep enough to set significant constraints on the continuum emission between the lines in the H-band. Methods. During the second commissioning run of the GIANO high-resolution infrared spectrograph at La Palma Observatory, we pointed the instrument directly at the sky and obtained a deep spectrum that extends from 0.97 to 2.4 μm. Results. The spectrum shows about 1500 emission lines, a factor of two more than in previous works. Of these, 80% are identified as OH transitions; half of these are from highly excited molecules (hot-OH component) that are not included in the OH airglow emission models normally used for astronomical applications. The other lines are attributable to O2 or unidentified. Several of the faint lines are in spectral regions that were previously believed to be free of line emission. The continuum in the H-band is marginally detected at a level of about 300 photons/m2/s/arcsec2/μm, equivalent to 20.1 AB-mag/arcsec2. The observed spectrum and the list of observed sky lines are published at the CDS. Conclusions. Our measurements indicate that the sky continuum in the H-band could be even darker than previously believed. However, the myriad of airglow emission lines severely limits the spectral ranges where very low background can be effectively achieved with low- or medium-resolution spectrographs. We identify a few spectral bands that could still remain quite dark at the resolving power foreseen for VLT-MOONS (R ≃ 6600).
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The GAPS Programme at TNG Scandariato, G.; Borsa, F.; Sicilia, D. ...
Astronomy and astrophysics (Berlin),
02/2021, Volume:
646
Journal Article
Peer reviewed
Open access
Context.
The analysis of exoplanetary atmospheres by means of high-resolution spectroscopy is an expanding research field which provides information on the chemical composition, thermal structure, ...atmospheric dynamics, and orbital velocity of exoplanets.
Aims.
In this work, we aim to detect the light reflected by the exoplanet 51 Peg b by employing optical high-resolution spectroscopy.
Methods.
To detect the light reflected by the planetary dayside, we used optical High Accuracy Radial velocity Planet Searcher and High Accuracy Radial velocity Planet Searcher for the Northern hemisphere spectra taken near the superior conjunction of the planet, when the flux contrast between the planet and the star is maximum. To search for the weak planetary signal, we cross-correlated the observed spectra with a high signal-to-noise ratio stellar spectrum.
Results.
We homogeneously analyze the available datasets and derive a 10
−5
upper limit on the planet-to-star flux contrast in the optical.
Conclusions.
The upper limit on the planet-to-star flux contrast of 10
−5
translates into a low albedo of the planetary atmosphere (
A
g
≲ 0.05−0.15 for an assumed planetary radius in the range of 1.5−0.9
R
Jup
, as estimated from the planet’s mass).
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Aims.In this paper, we present an innovative data reduction method for single-mode interferometry. It has been specifically developed for the AMBER instrument, the three-beam combiner of the Very ...Large Telescope Interferometer, but it can be derived for any single-mode interferometer. Methods.The algorithm is based on a direct modelling of the fringes in the detector plane. As such, it requires a preliminary calibration of the instrument in order to obtain the calibration matrix that builds the linear relationship between the interferogram and the interferometric observable, which is the complex visibility. Once the calibration procedure has been performed, the signal processing appears to be a classical least-square determination of a linear inverse problem. From the estimated complex visibility, we derive the squared visibility, the closure phase, and the spectral differential phase. Results.The data reduction procedures have been gathered into the so-called amdlib software, now available for the community, and are presented in this paper. Furthermore, each step in this original algorithm is illustrated and discussed from various on-sky observations conducted with the VLTI, with a focus on the control of the data quality and the effective execution of the data reduction procedures. We point out the present limited performances of the instrument due to VLTI instrumental vibrations which are difficult to calibrate.
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