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Search Results: 1 - 10 of 9854 matches for " Pablo Saz "
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Pulsar Results with the Fermi Large Area Telescope
Paul S. Ray,Pablo M. Saz Parkinson
Physics , 2010, DOI: 10.1007/978-3-642-17251-9_3
Abstract: The launch of the Fermi Gamma-ray Space Telescope has heralded a new era in the study of gamma-ray pulsars. The population of confirmed gamma-ray pulsars has gone from 6-7 to more than 60, and the superb sensitivity of the Large Area Telescope (LAT) on Fermi has allowed the detailed study of their spectra and light curves. Twenty-four of these pulsars were discovered in blind searches of the gamma-ray data, and twenty-one of these are, at present, radio quiet, despite deep radio follow-up observations. In addition, millisecond pulsars have been confirmed as a class of gamma-ray emitters, both individually and collectively in globular clusters. Recently, radio searches in the direction of LAT sources with no likely counterparts have been highly productive, leading to the discovery of a large number of new millisecond pulsars. Taken together, these discoveries promise a great improvement in the understanding of the gamma-ray emission properties and Galactic population of pulsars. We summarize some of the results stemming from these newly-detected pulsars and their timing and multi-wavelength follow-up observations.
Fermi-LAT Detection of Gamma-ray Pulsars above 10 GeV
Pablo M. Saz Parkinson,for the LAT Collaboration
Physics , 2012, DOI: 10.1063/1.4772255
Abstract: The Large Area Telescope (LAT) on board the Fermi satellite has detected ~120 pulsars above 100 MeV. While most gamma-ray pulsars have spectra that are well modeled by a power law with an exponential cut-off at around a few GeV, some show significant pulsed high-energy (HE, >10 GeV) emission. I present a study of HE emission from LAT gamma-ray pulsars and discuss prospects for the detection of pulsations at very high energies (VHE, >100 GeV) with ground-based instruments.
Fermi-LAT searches for gamma-ray pulsars
Pablo M. Saz Parkinson,for the Fermi LAT Collaboration
Physics , 2012, DOI: 10.1017/S174392131202323X
Abstract: The Large Area Telescope (LAT) on the Fermi satellite is the first gamma-ray instrument to discover pulsars directly via their gamma-ray emission. Roughly one third of the 117 gamma-ray pulsars detected by the LAT in its first three years were discovered in blind searches of gamma-ray data and most of these are undetectable with current radio telescopes. I review some of the key LAT results and highlight the specific challenges faced in gamma-ray (compared to radio) searches, most of which stem from the long, sparse data sets and the broad, energy-dependent point-spread function (PSF) of the LAT. I discuss some ongoing LAT searches for gamma-ray millisecond pulsars (MSPs) and gamma-ray pulsars around the Galactic Center. Finally, I outline the prospects for future gamma-ray pulsar discoveries as the LAT enters its extended mission phase, including advantages of a possible modification of the LAT observing profile.
Effect of probiotic species on irritable bowel syndrome symptoms: A bring up to date meta-analysis Efecto de los probióticos en los síntomas del síndrome del intestino irritable: un meta-análisis actualizado
María Ortiz-Lucas,Tobias Aurelio,Pablo Saz,Juan José Sebastián
Revista Espa?ola de Enfermedades Digestivas , 2013,
Abstract: Background and objectives: immune system alteration in irritable bowel syndrome (IBS) patients may be modulated by probiotics. We assessed the efficacy of some probiotic species in alleviating characteristic IBS symptoms. Material and methods: a meta-analysis of all identified randomized controlled trials comparing probiotics with placebo in treating IBS symptoms was performed with continuous data summarized using standardized mean differences (SMDs) with 95% confidence intervals (95% CIs), where appropriate. The random-effects model was employed in cases of heterogeneity; otherwise, fixed-effects models were used. Results: meta-analysis was performed with 10 of 24 studies identified as suitable for inclusion. Probiotics improved pain scores if they contained Bifidobacterium breve (SMD, -0.34; 95% CI, -0.66; -0.02), Bifidobacterium longum (SMD, -0.48; 95% CI, -0.91; -0.06), or Lactobacillus acidophilus (SMD, -0.31; 95% CI, -0.61; -0.01) species. Distension scores were improved by probiotics containing B. breve (SMD, -0.45; 95% CI, -0.77; -0.13), Bifidobacterium infantis, Lactobacillus casei, or Lactobacillus plantarum (SMD, -0.53; 95% CI, -1.00; -0.06) species. All probiotic species tested improved flatulence: B. breve (SMD, -0.42; 95% CI, -0.75;-0.10), B. infantis, L. casei, L. plantarum (SMD, -0.60; 95% CI, -1.07; -0.13), B. longum, L. acidophilus, Lactobacillus bulgaricus, and Streptococcus salivarius ssp. thermophilus (SMD, -0.61; 95% CI, -1.01; -0.21). There was not a clear positive effect of probiotics concerning the quality of life. Conclusions: some probiotics are an effective therapeutic option for IBS patients, and the effects on each IBS symptom are likely species-specific. Future studies must focus on the role of probiotics in modulating intestinal microbiota and the immune system while considering individual patient symptom profiles. Antecedentes y objetivos: la alteración del sistema inmune en los pacientes con síndrome del intestino irritable (SII) podría modularse por el efecto de los probióticos. Se evaluó la eficacia de algunas especies de probióticos en el alivio de síntomas característicos del SII. Material y métodos: se realizó un meta-análisis de todos los ensayos clínicos aleatorios identificados donde se comparaba los probióticos con el placebo en el tratamiento de síntomas del SII. El meta-análisis se realizó empleando datos continuos empleando diferencias de medias estandarizadas (DME) con intervalos de confianza del 95% (IC 95%). Se empleó el modelo de efectos aleatorios en casos de heterogeneidad, si no, el modelo de efectos f
The tale of the two tails of the oldish PSR J2055+2539
Martino Marelli,Daniele Pizzocaro,Andrea De Luca,Fabio Gastaldello,Patrizia Caraveo,Pablo Saz Parkinson
Physics , 2015,
Abstract: We analyzed a deep XMM-Newton observations of the radio-quiet gamma-ray PSR J2055+2539. The spectrum of the X-ray counterpart is non-thermal, with a photon index of 2.36$\pm$0.14 (1$\sigma$ confidence). We detected X-ray pulsations with a pulsed fraction of (25$\pm$3)% and a sinusoidal shape. Taking into account considerations on the gamma-ray efficiency of the pulsar and on its X-ray spectrum, we can infer a pulsar distance ranging from 450 pc to 750 pc. We found two different nebular features associated to PSR J2055+2539 and protruding from it. The angle between the two nebular main axes is $\sim$ (162.8$\pm$0.7) degrees. The main, brighter feature is 12'-long and <20"-thick, characterized by an asymmetry with respect to the main axis that evolves with the distance from the pulsar, possibly forming a helical pattern. The secondary feature is 250" x 30". Both nebulae present an almost flat brightness profile with a sudden decrease at the end. The nebulae can be fitted either by a power-law model or a thermal bremsstrahlung model. A plausible interpretation of the brighter nebula is in terms of a collimated ballistic jet. The secondary nebula is most likely a classical synchrotron-emitting tail.
PSR J0357+3205: the tail of the turtle
Martino Marelli,Andrea De Luca,David Salvetti,Nicola Sartore,Angelica Sartori,Patrizia Caraveo,Fabio Pizzolato,Pablo M. Saz Parkinson,Andrea Belfiore
Physics , 2012, DOI: 10.1088/0004-637X/765/1/36
Abstract: Using a new XMM-Newton observation, we have characterized the X-ray properties of the middle-aged radio-quiet gamma-ray pulsar J0357+3205 (named Morla) and its tail. The X-ray emission from the pulsar is consistent with a magnetospheric non-thermal origin plus a thermal emission from a hot spot (or hot spots). The lack of a thermal component from the whole surface makes Morla the coldest neutron star in its age range. We found marginal evidence for a double-peaked modulation of the X-ray emission. The study of the 9'-long tail confirmed the lack of extended emission near the pulsar itself. The tail shows a very asymmetric brightness profile and its spectrum lacks any spatial variation. We found the nebular emission to be inconsistent with a classical bow-shock, ram-pressure dominated pulsar wind nebula. We propose thermal bremsstrahlung as an alternative mechanism for Morla's tail emission. In this scenario, the tail emission comes from the shocked interstellar medium (ISM) material heated up to X-ray temperatures. This can fully explain the peculiar features of the tail, assuming a hot, moderately dense interstellar medium around the pulsar. For a bremsstrahlung-emitting tail, we can estimate the pulsar distance to be between 300 and 900 pc. A pulsar velocity of about 1900 km/s is required - which would make Morla the pulsar with the largest velocity - and high inclination angles (>70 degrees) are preferred. We propose Morla's nebula as the first example of a new "turtle's tail" class of thermally-emitting nebulae associated to high velocity pulsars.
La medicina y el enfermo oncológico
Pilar Espa?a Saz
Política y Sociedad , 2000, DOI: -
Abstract: Sin resumen
PARANEOPLASTIC SENSORY NEUROPATHY: REPORT OF 6 CASES
A CHIT SAZ
Journal of Research in Medical Sciences , 2002,
Abstract: Sometimes before signs of lung tumor, peripheral nerve involvement with sensory neuropathy tell us about lung cancer. This sensory neuropathy often accompany with oat cell carcinoma of lung. The initial symptoms are numbness or paresthesic in a limb and over a period of days or weeks symptoms became bilateral and spread to trunk. Areflexia and autonomic dysfunction as cardiac arrhythmia, gastric atonia, illeus and orthostatic hypotension accured. In CSF there is pleocytic Iyphmphocytes. Electra diagnostic test (NCV) compatible with loss of sensory potentials. In this survey in Alzahra hospitol (1999-2000) affiliated to IUMSHS, 64 patients with neuropathy, were investigated. Chest x-ray and lung CT scan was prepared for them. Bronchoscopy and biopsy of lung was done in indicated ones. On the other hand electrodiagnostic (NCV) and cerebrospinal fluid (CSF) study were done in then. Among 64 patients with neuropathy, six patients had lung tumors with sensory neuropathy. The commonest sign of diseas was limb paresthesia. In 84 percent of patients, tendon reflex in lower limbs was absent. The commonest tumor was out cell carcinoma of lung and 15 percent of patients had muscle pain in early phase of disease. CSF showed pleocytose of Iymphocytes. NCV showed absent of sensory potentials in 100 percent of patients.
Status and Prospects of Fermi LAT Pulsar Blind Searches
P. M. Saz Parkinson
Physics , 2011,
Abstract: Blind Searches of Fermi Large Area Telescope (LAT) data have resulted in the discovery of 24 gamma-ray pulsars in the first year of survey operations, most of which remain undetected in radio, despite deep radio follow-up searches. I summarize the latest Fermi LAT blind search efforts and results, including the discovery of a new Geminga-like pulsar, PSR J0734-1559. Finally, I discuss some of the challenges faced in carrying out these searches into the future, as well as the prospects for finding additional pulsars among the large number of LAT unassociated sources.
The symbol of a function of an operator
Alfonso Gracia-Saz
Mathematics , 2004,
Abstract: We give an explicit formula for the symbol of a function of an operator. Given an operator {\hat A} on L^2(R^N) with symbol A, and a function f, we obtain the symbol of f(\hat A) in terms of A. As an application, Bohr-Sommerfeld quantization rules are explicitely calculated at order 4 in hbar.
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