470 research outputs found
On the origin of \gamma-ray emission in \eta\ Carina
\eta\ Car is the only colliding-wind binary for which high-energy \gamma\
rays are detected. Although the physical conditions in the shock region change
on timescales of hours to days, the variability seen at GeV energies is weak
and on significantly longer timescales. The \gamma-ray spectrum exhibits two
features that can be interpreted as emission from the shocks on either side of
the contact discontinuity. Here we report on the first time-dependent modelling
of the non-thermal emission in \eta\ Car. We find that emission from primary
electrons is likely not responsible for the \gamma-ray emission, but
accelerated protons interacting with the dense wind material can explain the
observations. In our model, efficient acceleration is required at both shocks,
with the primary side acting as a hadron calorimeter, whilst on the companion
side acceleration is limited by the flow time out of the system, resulting in
changing acceleration conditions. The system therefore represents a unique
laboratory for the exploration of hadronic particle acceleration in
non-relativistic shocks.Comment: 5 pages, 4 figures, 1 table, accepted for publication in MNRAS
Letter
Contenido polínico anual de la atmósfera de Pamplona y su relación con las variables climatológicas diarias
Este trabaJo es un estudio del polen prosente en l a atmósfera de Pamplona, recogido di ar1amente durante un año comprend1do c nt.re e l 1 de abril de 1901 y el JO de marzo de 1982. Se estudia también la :-elac16n en tre el cont enido polinice y las vanables climatológicasThe at~ospherical pollcn of Pamplona is studied in l h1s work. The pollen was collected everyday durbg onc year , from l Apr il 1981 un'til 30 March 1962 . The r e l ation bet••een pollen amount and the climaUc va!'iabl es is al so s tudie
Estudio del polen atmosférico primaveral de la ciudad de Pamplona
El presente trabajo es un estudio del polen presente en la atmósfera de Pamplona, recogido diariamente durante los meses de marzo, abril, mayo, junio de 1978. Abstract: The spring atmospherical pollen of Pamplona is studied in this work. The pollen has been collected everyday during spring´s months of March, April, May, June in 1978
Hyperspectral imaging based detection of PVC during Sellafield repackaging procedures.
Traditionally, Special Nuclear Material (SNM) at Sellafield has been stored in multi-layered packages, consisting of metallic cans and an over-layer of plasticized Polyvinyl Chloride (PVC) as an intermediate layer when transitioning between areas of different radiological classification. However, it has been found that plasticized PVC can break down in the presence of both radiation and heat, releasing hydrochloric acid which can corrode these metallic containers. Therefore, internal repackaging procedures at Sellafield have focused recently on the removal of these PVC films from containers, where as much degraded and often adhered PVC as possible is manually removed based on visual inspection. This manual operation is time-consuming and it is possible that residual fragments of PVC could remain, leading to corrosion-related issues in future. In this work, Hyperspectral Imaging (HSI) was evaluated as a new tool for detecting PVC on metallic surfaces. Samples of stainless steel type 1.4404 – also known as 316L, the same as is used to construct SNM cans – and PVC were imaged in our experiments, and Support Vector Machine (SVM) classification models were used to generate detection maps. In these maps, pixels were classified into either PVC or 316L based on their spectral responses in the range 954-1700nm of the electromagnetic spectrum. Results suggest that HSI could be used for an effective automated detection and quantification of PVC during repackaging procedures, detection and quantification that could be extended to other similar applications
EFICACIA DEL LAVADO DE MANOS CON SOLUCIÓN DE BASE ALCOHÓLICA VERSUS EL LAVADO DE MANOS ESTÁNDAR CON JABÓN ANTISÉPTICO: ENSAYO CLÍNICO CONTROLADO Y ALEATORIZADO.
El síndrome facetar lumbar: Tratamiento mediante infiltraciones facetarias con fenol
Se presenta una serie de 125 pacientes afectos de cuadro de lumbociatalgia atípica, diagnosticados de síndrome facetario y tratados con infiltraciones de solución fenolada en las articulaciones interapofisarias posteriores afectadas, seguidas de un programa de rehabilitación protocolizado tras las infiltraciones. A propósito de los mismos y tras una análisis estadístico de los datos obtenidos del estudio, se establecen algunos criterios para el tratamiento de pacientes aquejados de este tipo de patología.The authors present a series of 125 patients afflicted with an atypical sciatic low-back pain, who were diagnosed of "facet joint syndrome" and treated with injections of phenol solution in the affected lumbar zygapophysial joints. The patients followed a protocolized rehabilitation program. After an statistical analysis of the data obtained from the study, some criteria are stabilized for the treatment of patients suffering this pathology
Candidate counterparts to the soft gamma-ray flare in the direction of LS i +61 303
Context. A short duration burst reminiscent of a soft gamma-ray repeater/anomalous X-ray pulsar behaviour was detected in the direction of LS I +61 303 by the Swift satellite. While the association with this well known gamma-ray binary is likely, a different origin cannot be excluded.
Aims. We explore the error box of this unexpected flaring event and establish the radio, near-infrared and X-ray sources in our search for any peculiar alternative counterpart.
Methods. We carried out a combined analysis of archive Very Large Array radio data of LS I +61 303 sensitive to both compact and extended emission. We also reanalysed previous near infrared observations with the 3.5 m telescope of the Centro Astronómico Hispano Alemn and X-ray observations with the Chandra satellite.
Results. Our deep radio maps of the LS I +61 303 environment represent a significant advancement on previous work and 16 compact radio sources in the LS I +61 303 vicinity are detected. For some detections, we also identify near infrared and X-ray counterparts. Extended emission features in the field are also detected and confirmed. The possible connection of some of these sources with the observed flaring event is considered. Based on these data, we are unable to claim a clear association between the Swift-BAT flare and any of the sources reported here. However, this study represents the most sophisticated attempt to determine possible alternative counterparts other than LS I +61 303.Facultad de Ciencias Astronómicas y Geofísica
Candidate counterparts to the soft gamma-ray flare in the direction of LS i +61 303
Context. A short duration burst reminiscent of a soft gamma-ray repeater/anomalous X-ray pulsar behaviour was detected in the direction of LS I +61 303 by the Swift satellite. While the association with this well known gamma-ray binary is likely, a different origin cannot be excluded.
Aims. We explore the error box of this unexpected flaring event and establish the radio, near-infrared and X-ray sources in our search for any peculiar alternative counterpart.
Methods. We carried out a combined analysis of archive Very Large Array radio data of LS I +61 303 sensitive to both compact and extended emission. We also reanalysed previous near infrared observations with the 3.5 m telescope of the Centro Astronómico Hispano Alemn and X-ray observations with the Chandra satellite.
Results. Our deep radio maps of the LS I +61 303 environment represent a significant advancement on previous work and 16 compact radio sources in the LS I +61 303 vicinity are detected. For some detections, we also identify near infrared and X-ray counterparts. Extended emission features in the field are also detected and confirmed. The possible connection of some of these sources with the observed flaring event is considered. Based on these data, we are unable to claim a clear association between the Swift-BAT flare and any of the sources reported here. However, this study represents the most sophisticated attempt to determine possible alternative counterparts other than LS I +61 303.Facultad de Ciencias Astronómicas y Geofísica
SK channels contribution to ventricular electrophysiology in heart failure patients
Heart failure (HF) is characterized by deterioration of the electrical and contractile function of the heart due to structural and functional remodelling, leading to development of arrhythmias and increased sudden cardiac death risk. SK channels are a type of calcium-activated potassium channels that do not play a relevant role in normal ventricular electrophysiology. However, it has been hypothesized that these channels become more relevant in pathologies such as HF. Nontheless, their role in human ventricular electrophysiology is not fully characterized
Radio continuum and near-infrared study of the MGRO J2019+37 region
(abridged) MGRO J2019+37 is an unidentified extended source of VHE gamma-rays
originally reported by the Milagro Collaboration as the brightest TeV source in
the Cygnus region. Its extended emission could be powered by either a single or
several sources. The GeV pulsar AGL J2020.5+3653, discovered by AGILE and
associated with PSR J2021+3651, could contribute to the emission from MGRO
J2019+37, although extrapolation of the GeV spectrum does not explain the
detected multi-TeV flux. Our aim is to identify radio and NIR sources in the
field of the extended TeV source MGRO J2019+37, and study potential
counterparts that could contribute to its emission. We surveyed a region of
about 6 square degrees with the Giant Metrewave Radio Telescope (GMRT) at the
frequency 610 MHz. We also observed the central square degree of this survey in
the NIR Ks-band using the 3.5 m telescope in Calar Alto. Archival X-ray
observations of some specific fields are included. VLBI observations of an
interesting radio source were performed. We explored possible scenarios to
produce the multi-TeV emission from MGRO J2019+37 and studied which of the
sources could be the main particle accelerator. We present a catalogue of 362
radio sources detected with the GMRT in the field of MGRO J2019+37, and the
results of a cross-correlation of this catalog with one obtained at NIR
wavelengths, as well as with available X-ray observations of the region. Some
peculiar sources inside the ~1 degree uncertainty region of the TeV emission
from MGRO J2019+37 are discussed in detail, including the pulsar PSR J2021+3651
and its pulsar wind nebula PWN G75.2+0.1, two new radio-jet sources, the HII
region Sh 2-104 containing two star clusters, and the radio source NVSS
J202032+363158.Comment: 10 pages, 6 figures, 2 tables, accepted for publication in Astronomy
and Astrophysic
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