800 research outputs found
First images on the sky from a hyper telescope
We show star images obtained with a miniature ``densified pupil imaging
interferometer'' also called a hyper-telescope. The formation of such images
violates a ``golden rule of imaging interferometers'' which appeared to forbid
the use of interferometric arrangements differing from a Fizeau interferometer.
These produce useless images when the sub-apertures spacing is much wider than
their size, owing to diffraction through the sub-apertures. The hyper-telescope
arrangement solves these problems opening the way towards multi-kilometer
imaging arrays in space. We experimentally obtain an intensity gain of 24 +- 3X
when a densified-pupil interferometer is compared to an equivalent Fizeau-type
interferometer and show images of the double star alpha Gem. The initial
results presented confirm the possibility of directly obtaining high resolution
and high dynamic range images in the recombined focal plane of a large
interferometer if enough elements are used.Comment: 6 pages, LaTeX, standard A&A macros + BibTeX macros. Accepted for
publication in Astronomy and Astrophysics Supplement
Type 2 Diabetes Mellitus: A Review of Multi-Target Drugs
Diabetes Mellitus (DM) is a multi-factorial chronic health condition that affects a large part of population and according to the World Health Organization (WHO) the number of adults living with diabetes is expected to increase. Since type 2 diabetes mellitus (T2DM) is suffered by the majority of diabetic patients (around 90-95%) and often the mono-target therapy fails in managing blood glucose levels and the other comorbidities, this review focuses on the potential drugs acting on multi-targets involved in the treatment of this type of diabetes. In particular, the review considers the main systems directly involved in T2DM or involved in diabetes comorbidities. Agonists acting on incretin, glucagon systems, as well as on peroxisome proliferation activated receptors are considered. Inhibitors which target either aldose reductase and tyrosine phosphatase 1B or sodium glucose transporters 1 and 2 are taken into account. Moreover, with a view at the multi-target approaches for T2DM some phytocomplexes are also discussed
‘Fratelli del mondo’ : il calcio come pratica culturale e linguaggio globale
Alla luce del recente ingresso della Cina nell\u2019arena degli sport globali, Il saggio mira a collocare il gioco del calcio, e la cultura che lo accompagna e se ne nutre, entro la storia degli studi culturali, dimostrando come esso possa servire da prezioso strumento analitico per comprendere aspetti essenziali della contemporaneit\ue0 e accedere a pratiche di mediazione interculturale
CHARA/MIRC observations of two M supergiants in Perseus OB1: temperature, Bayesian modeling, and compressed sensing imaging
Two red supergiants of the Per OB1 association, RS Per and T Per, have been
observed in H band using the MIRC instrument at the CHARA array. The data show
clear evidence of departure from circular symmetry. We present here new
techniques specially developed to analyze such cases, based on state-of-the-art
statistical frameworks. The stellar surfaces are first modeled as limb-darkened
discs based on SATLAS models that fit both MIRC interferometric data and
publicly available spectrophotometric data. Bayesian model selection is then
used to determine the most probable number of spots. The effective surface
temperatures are also determined and give further support to the recently
derived hotter temperature scales of red su- pergiants. The stellar surfaces
are reconstructed by our model-independent imaging code SQUEEZE, making use of
its novel regularizer based on Compressed Sensing theory. We find excellent
agreement between the model-selection results and the reconstructions. Our
results provide evidence for the presence of near-infrared spots representing
about 3-5% of the stellar flux
[Measuring change in rehabilitative cardiology: reliability of a short questionnaire to assess an outcome].
The present Italian health planning demands the use of tools, care and treatments useful for the National Health Service, but with empirical effectiveness scientifically sustained. Aim of the present paper is to verify the validity, the reliability and the responsiveness of the factor "Perception of positive change" (named Schedule C) in cardiovascular rehabilitation. Method. The reliability of the Schedule C of the CBA VE has been examined comparing the mean scores obtained from each item at the entry and just before the discharge through the t-Student for paired sample. To assess the concurrent validity we used the AD Short Scale to measure anxiety and depression. 100 patients who underwent cardiac surgery were enrolled during hospitalization for a Cardiac Rehabilitation Programme. Cronbach's alpha was used to assess internal consistency of each item. Results. Each item of the Schedule C demonstrated good internal consistency (Cronbach Alpha >.88) and elevated correlations item-total for each item. The strong correlation of anxiety and depression scores with the Schedule C points out appropriate concurrent validation. Conclusions. We believe that the Schedule C of the CBA VE is endowed with suitable metric validity and then useful as outcome evaluation in cardiovascular rehabilitation settings
Imaging the Algol Triple System in H Band with the CHARA Interferometer
Algol (Beta Per) is an extensively studied hierarchical triple system whose
inner pair is a prototype semi-detached binary with mass transfer occurring
from the sub-giant secondary to the main-sequence primary. We present here the
results of our Algol observations made between 2006 and 2010 at the CHARA
interferometer with the Michigan Infrared Combiner in the H band. The use of
four telescopes with long baselines allows us to achieve better than 0.5 mas
resolution and to unambiguously resolve the three stars. The inner and outer
orbital elements, as well as the angular sizes and mass ratios for the three
components are determined independently from previous studies. We report a
significantly improved orbit for the inner stellar pair with the consequence of
a 15% change in the primary mass compared to previous studies. We also
determine the mutual inclination of the orbits to be much closer to
perpendicularity than previously established. State-of-the-art image
reconstruction algorithms are used to image the full triple system. In
particular an image sequence of 55 distinct phases of the inner pair orbit is
reconstructed, clearly showing the Roche-lobe-filling secondary revolving
around the primary, with several epochs corresponding to the primary and
secondary eclipses
Multiplicity of Galactic Cepheids from long-baseline interferometry I. CHARA/MIRC detection of the companion of V1334 Cygni
We aim at determining the masses of Cepheids in binary systems, as well as
their geometric distances and the flux contribution of the companions. The
combination of interferometry with spectroscopy will offer a unique and
independent estimate of the Cepheid masses. Using long-baseline interferometry
at visible and infrared wavelengths, it is possible to spatially resolve binary
systems containing a Cepheid down to milliarcsecond separations. Based on the
resulting visual orbit and radial velocities, we can then derive the
fundamental parameters of these systems, particularly the masses of the
components and the geometric distance. We therefore performed interferometric
observations of the first-overtone mode Cepheid V1334 Cyg with the CHARA/MIRC
combiner. We report the first detection of a Cepheid companion using
long-baseline interferometry. We detect the signature of a companion orbiting
V1334 Cyg at two epochs. We measure a flux ratio between the companion and the
Cepheid f = 3.10+/-0.08%, giving an apparent magnitude mH = 8.47+/-0.15mag. The
combination of interferometric and spectroscopic data have enabled the unique
determination of the orbital elements: P = 1938.6+/-1.2 days, Tp = 2 443
616.1+/-7.3, a = 8.54+/-0.51mas, i = 124.7+/-1.8{\deg}, e = 0.190+/-0.013,
{\omega} = 228.7+/-1.6{\deg}, and {\Omega} = 206.3+/-9.4{\deg}. We derive a
minimal distance d ~ 691 pc, a minimum mass for both stars of 3.6 Msol, with a
spectral type earlier than B5.5V for the companion star. Our measured flux
ratio suggests that radial velocity detection of the companion using
spectroscopy is within reach, and would provide an orbital parallax and
model-free masses.Comment: Published in A&
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