17 research outputs found

    Probing the Inner Jet of the Quasar PKS 1510-089 with Multi-waveband Monitoring during Strong Gamma-ray Activity

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    We present results from monitoring the multi-waveband flux, linear polarization, and parsec-scale structure of the quasar PKS 1510-089, concentrating on eight major gamma-ray flares that occurred during the interval 2009.0-2009.5. The gamma-ray peaks were essentially simultaneous with maxima at optical wavelengths, although the flux ratio of the two wavebands varied by an order of magnitude. The optical polarization vector rotated by 720 degrees during a 5-day period encompassing six of these flares. This culminated in a very bright, roughly 1 day, optical and gamma-ray flare as a bright knot of emission passed through the highest-intensity, stationary feature (the "core") seen in 43 GHz Very Long Baseline Array images. The knot continued to propagate down the jet at an apparent speed of 22c and emit strongly at gamma-ray energies as a months-long X-ray/radio outburst intensified. We interpret these events as the result of the knot following a spiral path through a mainly toroidal magnetic field pattern in the acceleration and collimation zone of the jet, after which it passes through a standing shock in the 43 GHz core and then continues downstream. In this picture, the rapid gamma-ray flares result from scattering of infrared seed photons from a relatively slow sheath of the jet as well as from optical synchrotron radiation in the faster spine. The 2006-2009.7 radio and X-ray flux variations are correlated at very high significance; we conclude that the X-rays are mainly from inverse Compton scattering of infrared seed photons by 20-40 MeV electrons.Comment: 10 pages of text + 5 figures, to be published in Astrophysical Journal Letters in 201

    On the Location of the Gamma-ray Emission in the 2008 Outburst in the BL Lacertae Object AO 0235+164 through Observations across the Electromagnetic Spectrum

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    We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array (VLBA) images at 7mm with 0.15 milliarcsecond resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte-Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary "core" and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight by light-travel time delays, that passes through a standing recollimation shock in the core and propagates down the jet to create the superluminal knot. The multi-wavelength light curves vary together on long time-scales (months/years), but the correspondence is poorer on shorter time-scales. This, as well as the variability of the polarization and the dual location of the outburst, agrees with the expectations of a multi-zone emission model in which turbulence plays a major role in modulating the synchrotron and inverse Compton fluxes.Comment: Accepted for Publication in the Astrophysical Journal Letters. 7 pages (including 5 figures). Minor corrections with regard to previous version, as proposed by the refere

    Flaring Behavior of the Quasar 3C~454.3 across the Electromagnetic Spectrum

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    We analyze the behavior of the parsec-scale jet of the quasar 3C~454.3 during pronounced flaring activity in 2005-2008. Three major disturbances propagated down the jet along different trajectories with Lorentz factors Γ>\Gamma>10. The disturbances show a clear connection with millimeter-wave outbursts, in 2005 May/June, 2007 July, and 2007 December. High-amplitude optical events in the RR-band light curve precede peaks of the millimeter-wave outbursts by 15-50 days. Each optical outburst is accompanied by an increase in X-ray activity. We associate the optical outbursts with propagation of the superluminal knots and derive the location of sites of energy dissipation in the form of radiation. The most prominent and long-lasting of these, in 2005 May, occurred closer to the black hole, while the outbursts with a shorter duration in 2005 Autumn and in 2007 might be connected with the passage of a disturbance through the millimeter-wave core of the jet. The optical outbursts, which coincide with the passage of superluminal radio knots through the core, are accompanied by systematic rotation of the position angle of optical linear polarization. Such rotation appears to be a common feature during the early stages of flares in blazars. We find correlations between optical variations and those at X-ray and γ\gamma-ray energies. We conclude that the emergence of a superluminal knot from the core yields a series of optical and high-energy outbursts, and that the mm-wave core lies at the end of the jet's acceleration and collimation zone.Comment: 57 pages, 23 figures, 8 tables (submitted to ApJ

    Alfabetización para la salud: Propuestas e Ideas para cuidar y cuidarnos. MOOC abierto al debate en Twitter bajo el hashtag #alfabeSaludUOC.

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    Informe del diseño y desarrollo del MOOC Alfabetización para la salud: propuestas e ideas para cuidar y cuidarnos, promovido por el eHealth Center de la UOC. Incluye las aportaciones de todos los participantes en Twitter durante el período en que el curso estuvo dinamizado; proyectos, ideas y debates.Informe del disseny i desenvolupament del MOOC Alfabetización para la salud, para la salud: propuestas e ideas para cuidar y cuidarnos, promogut per l¿eHealth Center de la UOC. Inclou les aportacions de tots els participants a Twitter durant el període en què el curs va estar dinamitzat; projectes, idees i debats.Report on the design and development of the MOOC Alfabetización para la salud, para la salud: propuestas e ideas para cuidar y cuidarnos [Health Literacy: proposals and ideas for caring and looking after ourselves], promoted by the UOC's eHealth Center. It includes the contributions of all the participants on Twitter during the period in which the course was actively run; projects, ideas and debates

    The efficiency of telemedicine to optimize metabolic control in patients with type 1 diabetes mellitus: Telemed study

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    Objective: This study evaluated the impact of an Internet-based telematic system on the economic and clinical management of patients with type 1 diabetes mellitus. Research Design and Methods: This 6-month prospective, randomized, comparative, open, multicenter study included patients with type 1 diabetes >18 years old treated with multiple insulin doses and with a glycated hemoglobin (HbA1c) level of >8%. We compared an intervention group (IG) (two face-to-face and five telematic appointments) with a control group (CG) (seven face-to-face appointments). The variables studied were (1) patient and healthcare team costs, (2) metabolic control, (3) knowledge of diabetes, (4) quality of life, and (5) self-care treatment adherence. Results: Of the 154 patients included, 118 (76.6%) completed the study (IG, 54; CG, 64). The time used by the CG to follow the program was 823±645 min versus 353±222 min in the IG (P<0.0001). Compared with the CG, the IG required less healthcare time from the professionals (288±105 min vs. 232±89 min; P<0.001). HbA1c improved in both groups (IG, 9.2±1.5% [77.0±17.0 mmol/mol] vs. 8.7±1.5% [71.6±17.0 mmol/mol] [P<0.001]; CG, 9.2±0.9% [77.0±10.0 mmol/mol] vs. 8.6±0.9% [70.5±10.0 mmol/mol] [P<0.001], as did knowledge and self-care treatment adherence. Conclusions: The use of interactive telematic appointments in subjects with type 1 diabetes and inadequate metabolic control is an efficient strategy, providing results comparable to those of face-to-face appointments in relation to improvement in glycemic control, knowledge acquisition, and self-care treatment adherence, with a significant reduction in the time used, especially by patients

    The future of European universities

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    This ESIR Focus Paper provides a ‘deeper dive’ into the role of European Universities in achieving systemic change in the post-pandemic economy and society. It builds on and complements ESIR’s second Policy Brief, which offers guidance on how a ‘protect-prepare-transform’ approach in the post-pandemic Europe can ensure fast learning from innovation by relying on smart and coherent policies, collaborative efforts across levels of government and decentralisation of governance, and most importantly the courage to direct research and innovation at the transformations Europe is facing

    Prevalence and risk factors of infections by multiresistant bacteria in cirrhosis: A prospective study

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    Epidemiology, risk factors, and clinical effect of infections by multiresistant bacteria in cirrhosis are poorly known. This work was a prospective evaluation in two series of cirrhotic patients admitted with infection or developing infection during hospitalization. The first series was studied between 2005 and 2007 (507 bacterial infections in 223 patients) and the second between 2010 and 2011 (162 bacterial infections in 110 patients). In the first series, 32% of infections were community acquired (CA), 32% healthcare associated (HCA), and 36% nosocomial. Multiresistant bacteria (92 infections; 18%) were isolated in 4%, 14%, and 35% of these infections, respectively (P < 0.001). Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E; n = 43) was the main multiresistant organism identified, followed by Pseudomonas aeruginosa (n = 17), methicillin-resistant Staphylococcus aureus (n = 14), and Enterococcus faecium (n = 14). The efficacy of currently recommended empirical antibiotic therapy was very low in nosocomial infections (40%), compared to HCA and CA episodes (73% and 83%, respectively; P < 0.0001), particularly in spontaneous bacterial peritonitis, urinary tract infection, and pneumonia (26%, 29%, and 44%, respectively). Septic shock (26% versus 10%; P < 0.0001) and mortality rate (25% versus 12%; P = 0.001) were significantly higher in infections caused by multiresistant strains. Nosocomial origin of infection (hazard ratio [HR], 4.43), long-term norfloxacin prophylaxis (HR, 2.69), recent infection by multiresistant bacteria (HR, 2.45), and recent use of β-lactams (HR, 2.39) were independently associated with the development of multiresistant infections. Results in the second series were similar to those observed in the first series. Conclusions: Multiresistant bacteria, especially ESBL-producing Enterobacteriaceae, are frequently isolated in nosocomial and, to a lesser extent, HCA infections in cirrhosis, rendering third-generation cephalosporins clinically ineffective. New antibiotic strategies tailored according to the local epidemiological patterns are needed for the empirical treatment of nosocomial infections in cirrhosis. © 2011 American Association for the Study of Liver Diseases

    Mobilising innovation for people, planet and prosperity

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    Publication metadata ESIR is a high-level expert group that provides evidence-based policy advice to the European Commission on how to develop a forward-looking and transformative research and innovation policy. This will help drive Europe's transition to full sustainability. In this publication, ESIR offers guidance on how a ‘protect-prepare-transform’ approach can ensure fast learning from innovation by relying on smart and coherent policies, collaborative efforts across levels of government and decentralisation of governance, and most importantly the courage to direct research and innovation at the transformations Europe is facing
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