808 research outputs found
The LOFT (Large Observatory for X-ray Timing) background simulations
The Large Observatory For X-ray Timing (LOFT) is an innovative medium-class
mission selected for an assessment phase in the framework of the ESA M3 Cosmic
Vision call. LOFT is intended to answer fundamental questions about the
behaviour of matter in the very strong gravitational and magnetic fields around
compact objects. With an effective area of ~10 m^2 LOFT will be able to measure
very fast variability in the X-ray fluxes and spectra. A good knowledge of the
in-orbit background environment is essential to assess the scientific
performance of the mission and to optimize the instrument design. The two main
contributions to the background are cosmic diffuse X-rays and high energy
cosmic rays; also, albedo emission from the Earth is significant. These
contributions to the background for both the Large Area Detector and the Wide
Field Monitor are discussed, on the basis of extensive Geant-4 simulations of a
simplified instrumental mass model.Comment: Proceedings of SPIE, Vol. 8443, Paper No. 8443-209, 201
Caregiver distress in the early phases of cancer
Principal caregivers (PCs) of cancer patients experience high levels of stress that may significantly impact their quality of life (QoL). PCs' QoL during early phases of the disease (when patients were still on chemotherapy) were assessed
Caregiver distress in the early phases of cancer
Principal caregivers (PCs) of cancer patients experience high levels of stress that may significantly impact their quality of life (QoL). PCs' QoL during early phases of the disease (when patients were still on chemotherapy) were assessed
El clima vitĂcola de las regiones productoras de uvas para vinos de Argentina.
El territorio continental americano de la Argentina está situado entre las latitudes 21° 46’ S y 55° 03’ S y longitudes 53° 38’ O y 73° 34’ O (Instituto Geográfico Militar). Los principales tipos de clima de la Argentina son cuatro: cálido, templado, árido y frĂo. En la Figura 1A se observa que la extensiĂłn del territorio y los accidentes del relieve, principalmente la Cordillera de los Andes, determinan la existencia de variaciones climáticas en cada uno de los tipos citados (Servicio MeteorolĂłgico Nacional). En la Argentina, la vitivinicultura orientada a la producciĂłn de vinos finos se desarrolla principalmente en la zona pedemontana de la Cordillera de Los Andes desde los 22° hasta los 42° de latitud Sur
Measurement of the effect of Non Ionising Energy Losses on the leakage current of Silicon Drift Detector prototypes for the LOFT satellite
The silicon drift detectors are at the basis of the instrumentation aboard
the Large Observatory For x-ray Timing (LOFT) satellite mission, which
underwent a three year assessment phase within the "Cosmic Vision 2015 - 2025"
long-term science plan of the European Space Agency. Silicon detectors are
especially sensitive to the displacement damage, produced by the non ionising
energy losses of charged and neutral particles, leading to an increase of the
device leakage current and thus worsening the spectral resolution.
During the LOFT assessment phase, we irradiated two silicon drift detectors
with a proton beam at the Proton Irradiation Facility in the accelerator of the
Paul Scherrer Institute and we measured the increase in leakage current. In
this paper we report the results of the irradiation and we discuss the impact
of the radiation damage on the LOFT scientific performance.Comment: 21 pages, 7 figures, 2 tables. Accepted for publication by Journal of
Instrumentation (JINST
Gamma-ray observations of Cygnus X-1 above 100 MeV in the hard and soft states
We present the results of multi-year gamma-ray observations by the AGILE
satellite of the black hole binary system Cygnus X-1. In a previous
investigation we focused on gamma-ray observations of Cygnus X-1 in the hard
state during the period mid-2007/2009. Here we present the results of the
gamma-ray monitoring of Cygnus X-1 during the period 2010/mid-2012 carried out
for which includes a remarkably prolonged `soft state' phase (June 2010 -- May
2011). Previous 1--10 MeV observations of Cyg X-1 in this state hinted at a
possible existence of a non-thermal particle component with substantial
modifications of the Comptonized emission from the inner accretion disk. Our
AGILE data, averaged over the mid-2010/mid-2011 soft state of Cygnus X-1,
provide a significant upper limit for gamma-ray emission above 100 MeV of
F_soft < 20 x 10^{-8} ph/cm^2/s, excluding the existence of prominent
non-thermal emission above 100 MeV during the soft state of Cygnus X-1. We
discuss theoretical implications of our findings in the context of high-energy
emission models of black hole accretion. We also discuss possible gamma-ray
flares detected by AGILE. In addition to a previously reported episode observed
by AGILE in October 2009 during the hard state, we report a weak but important
candidate for enhanced emission which occurred at the end of June 2010
(2010-06-30 10:00 - 2010-07-02 10:00 UT) exactly in coincidence with a
hard-to-soft state transition and before an anomalous radio flare. An appendix
summarizes all previous high-energy observations and possible detections of
Cygnus X-1 above 1 MeV.Comment: 16 pages, 12 figures, 1 table, accepted for publication in Ap
Simulations of the X-ray imaging capabilities of the Silicon Drift Detectors (SDD) for the LOFT Wide Field Monitor
The Large Observatory For X-ray Timing (LOFT), selected by ESA as one of the
four Cosmic Vision M3 candidate missions to undergo an assessment phase, will
revolutionize the study of compact objects in our galaxy and of the brightest
supermassive black holes in active galactic nuclei. The Large Area Detector
(LAD), carrying an unprecedented effective area of 10 m^2, is complemented by a
coded-mask Wide Field Monitor, in charge of monitoring a large fraction of the
sky potentially accessible to the LAD, to provide the history and context for
the sources observed by LAD and to trigger its observations on their most
interesting and extreme states. In this paper we present detailed simulations
of the imaging capabilities of the Silicon Drift Detectors developed for the
LOFT Wide Field Monitor detection plane. The simulations explore a large
parameter space for both the detector design and the environmental conditions,
allowing us to optimize the detector characteristics and demonstrating the
X-ray imaging performance of the large-area SDDs in the 2-50 keV energy band.Comment: Proceedings of SPIE, Vol. 8443, Paper No. 8443-210, 201
Prognostic value of vascular endothelial growth factor tumor tissue content of colorectal cancer
A longitudinal study was designed to quantify tumor tissue content of vascular endothelial growth factor (VEGF) in patients with colorectal cancer (CRC) and to evaluate its prognostic value in respect to the relapse-free and overall survivals
Fulminant myocarditis parvovirus B19 related in a young woman
We present the case of a 18-year-old female with fulminant lymphocytic myocarditis caused by Parvovirus B19 (PVB19), successfully treated using temporary LVAD. In the literature there is no consensus on the surgical strategy. While some surgeons prefer to use a single device supporting only the LV, others prefer to start immediately with a biventricular supporting. At pre-procedural ultrasound evaluation, her anatomical features were not suitable for a percutaneous device such as the Impella. Thus, a temporary paracorporeal continuous flow LVAD was inserted. The heart recovery allowed LVAD removal 9 days after the implant
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