793 research outputs found
Practice parameters for the treatment of colonic diverticular disease: Italian Society of Colon and Rectal Surgery (SICCR) guidelines
The mission of the Italian Society of Colorectal Surgery (SICCR) is to optimize patient care. Providing evidence-based practice guidelines is therefore of key importance. About the present report it concernes the SICCR practice guidelines for the diagnosis and treatment of diverticular disease of the colon. The guidelines are not intended to define the sole standard of care but to provide evidence-based recommendations regarding the available therapeutic options
TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and WASP-1b
We present four new light curves of transiting exoplanets WASP-1b and
HAT-P-20b, observed within the TASTE (The Asiago Search for Transit timing
variations of Exoplanets) project. We re-analyzed light curves from the
literature in a homogeneous way, calculating a refined ephemeris and
orbital-physical parameters for both objects. WASP-1b does not show any
significant Transit Timing Variation signal at the 120 s-level. As for
HAT-P-20b, we detected a deviation from our re-estimated linear ephemeris that
could be ascribed to the presence of a perturber or, more probably, to a
previously unnoticed high level of stellar activity. The rotational period of
HAT-P-20 A we obtained from archival data (P_rot ~ 14.5 days), combined with
its optical variability and strong emission of CaII H&K lines, is consistent
with a young stellar age (< 1 Gyr) and support the hypothesis that stellar
activity may be responsible of the measured deviations of the transit times.Comment: 7 pages, 4 figures, 3 tables, accepted to Astronomische Nachrichte
High-precision astrometry with VVV. I. An independent reduction pipeline for VIRCAM@VISTA
We present a new reduction pipeline for the VIRCAM@VISTA detector and
describe the method developed to obtain high-precision astrometry with the
VISTA Variables in the V\'ia L\'actea (VVV) data set. We derive an accurate
geometric-distortion correction using as calibration field the globular cluster
NGC 5139, and showed that we are able to reach a relative astrometric precision
of about 8 mas per coordinate per exposure for well-measured stars over a field
of view of more than 1 square degree. This geometric-distortion correction is
made available to the community. As a test bed, we chose a field centered
around the globular cluster NGC 6656 from the VVV archive and computed proper
motions for the stars within. With 45 epochs spread over four years, we show
that we are able to achieve a precision of 1.4 mas/yr and to isolate each
population observed in the field (cluster, Bulge and Disk) using proper
motions. We used proper-motion-selected field stars to measure the motion
difference between Galactic disk and bulge stars. Our proper-motion
measurements are consistent with UCAC4 and PPMXL, though our errors are much
smaller. Models have still difficulties in reproducing the observations in this
highly-reddened Galactic regions.Comment: 11 pages, 10 figures (some in low res), 1 table. Accepted for
publication in MNRAS on March 25, 2015. The FORTRAN routine will be soon made
available at http://groups.dfa.unipd.it/ESPG/ , and via email request to the
first autho
TASTE. III. A homogeneous study of transit time variations in WASP-3b
The TASTE project is searching for low-mass planets with the Transit Timing
Variation (TTV) technique, by gathering high-precision, short-cadence light
curves for a selected sample of transiting exoplanets. It has been claimed that
the "hot Jupiter" WASP-3b could be perturbed by a second planet. Presenting
eleven new light curves (secured at the IAC80 and UDEM telescopes) and
re-analyzing thirty-eight archival light curves in a homogeneous way, we show
that new data do not confirm the previously claimed TTV signal. However, we
bring evidence that measurements are not consistent with a constant orbital
period, though no significant periodicity can be detected. Additional dynamical
modeling and follow-up observations are planned to constrain the properties of
the perturber or to put upper limits to it. We provide a refined ephemeris for
WASP-3b and improved orbital/physical parameters. A contact eclipsing binary,
serendipitously discovered among field stars, is reported here for the first
time.Comment: 10 pages, 6 figures, 4 tables; accepted for publication in A&
Normative EMG activation patterns of school-age children during gait
Gait analysis is widely used in clinics to study walking abnormalities for surgery planning, definition of rehabilitation protocols, and objective evaluation of clinical outcomes. Surface electromyography allows the study of muscle activity non-invasively and the evaluation of the timing of muscle activation during movement. The aim of this study was to present a normative dataset of muscle activation patterns obtained from a large number of strides in a population of 100 healthy children aged 6-11 years. The activity of Tibialis Anterior, Lateral head of Gastrocnemius, Vastus Medialis, Rectus Femoris and Lateral Hamstrings on both lower limbs was analyzed during a 2.5-min walk at free speed. More than 120 consecutive strides were analyzed for each child, resulting in approximately 28,000 strides. Onset and offset instants were reported for each observed muscle. The analysis of a high number of strides for each participant allowed us to obtain the most recurrent patterns of activation during gait, demonstrating that a subject uses a specific muscle with different activation modalities even in the same walk. The knowledge of the various activation patterns and of their statistics will be of help in clinical gait analysis and will serve as reference in the design of future gait studies
The M4 Core Project with HST --- I. Overview and First-Epoch
We present an overview of the ongoing Hubble Space Telescope large program
GO-12911. The program is focused on the core of M4, the nearest Galactic
globular cluster, and the observations are designed to constrain the number of
binaries with massive companions (black holes, neutron stars, or white dwarfs)
by measuring the ``wobble'' of the luminous (main-sequence) companion around
the center of mass of the pair, with an astrometric precision of ~50
micro-arcseconds. The high spatial resolution and stable medium-band PSFs of
WFC3/UVIS will make these measurements possible. In this work we describe: (i)
the motivation behind this study, (ii) our observing strategy, (iii) the many
other investigations enabled by this unique data set, and which of those our
team is conducting, and (iv) a preliminary reduction of the first-epoch
data-set collected on October 10, 2012.Comment: 25 pages, 14 figures (9 at low resolution), 3 tables. Published in:
Astronomische Nachrichten, Volume 334, Issue 10, pages 1062-1085, December
2013. http://onlinelibrary.wiley.com/doi/10.1002/asna.201311911/abstrac
M4 Core Project with HST - III. Search for variable stars in the primary field
We present the results of a photometric search for variable stars in the core
of the Galactic globular cluster M4. The input data are a large and
unprecedented set of deep Hubble Space Telescope WFC3 images (large program
GO-12911; 120 orbits allocated), primarily aimed at probing binaries with
massive companions by detecting their astrometric wobbles. Though these data
were not optimised to carry out a time-resolved photometric survey, their
exquisite precision, spatial resolution and dynamic range enabled us to firmly
detect 38 variable stars, of which 20 were previously unpublished. They include
19 cluster-member eclipsing binaries (confirming the large binary fraction of
M4), RR Lyrae, and objects with known X-ray counterparts. We improved and
revised the parameters of some among published variables.Comment: 11 pages, 5 figures, 2 tables. Accepted for publication in MNRA
Normative EMG activation patterns of school-age children during gait
Gait analysis is widely used in clinics to study walking abnormalities for surgery planning, definition of rehabilitation protocols, and objective evaluation of clinical outcomes. Surface electromyography allows the study of muscle activity non-invasively and the evaluation of the timing of muscle activation during movement. The aim of this study was to present a normative dataset of muscle activation patterns obtained from a large number of strides in a population of 100 healthy children aged 6-11 years. The activity of Tibialis Anterior, Lateral head of Gastrocnemius, Vastus Medialis, Rectus Femoris and Lateral Hamstrings on both lower limbs was analyzed during a 2.5-min walk at free speed. More than 120 consecutive strides were analyzed for each child, resulting in approximately 28,000 strides. Onset and offset instants were reported for each observed muscle. The analysis of a high number of strides for each participant allowed us to obtain the most recurrent patterns of activation during gait, demonstrating that a subject uses a specific muscle with different activation modalities even in the same walk. The knowledge of the various activation patterns and of their statistics will be of help in clinical gait analysis and will serve as reference in the design of future gait studie
A possibly inflated planet around the bright, young star DS Tuc A
The origin of the observed diversity of planetary system architectures is one
of the main topic of the exoplanetary research. The detection of a
statistically significant sample of planets around young stars allows us to
study the early stages of planet formation and evolution, but only a handful of
them is known so far. In this regard, a considerable contribution is expected
from the NASA TESS satellite, which is now performing a survey of
of the sky to search for short-period transiting planets In its first month of
operations, TESS found a planet candidate with an orbital period of 8.14 days
around a member of the Tuc-Hor young association ( 40 Myr), the G6V main
component of the binary system DS\,Tuc. If confirmed, it would be the first
transiting planet around a young star suitable for radial velocity and/or
atmospheric characterization. We aim to validate the planetary nature of this
companion and to measure its orbital and physical parameters. We obtain
accurate planet parameters by coupling an independent reprocessing of the TESS
light curve with improved stellar parameters and the dilution caused by the
binary companion; we analyse high precision archival radial velocities to
impose an upper limit of about 0.1 M on the planet mass; we finally
rule out the presence of external companions beyond 40 au with adaptive optics
images. We confirm the presence of a young, giant ( R) planet having a not negligible possibility to be inflated (theoretical
mass M) around DS\,Tuc~A. We discuss the feasibility
of mass determination, Rossiter-McLaughlin analysis and atmosphere
characterization, allowed by the brightness of the star.Comment: 12 pages, 11 figures. Accepted for publication in A&
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