X-ray burst induced spectral variability in 4U 1728-34

Aims. INTEGRAL has been monitoring the Galactic center region for more than a decade. Over this time INTEGRAL has detected hundreds of type-I X-ray bursts from the neutron star low-mass X-ray binary 4U 1728-34, a.k.a. "the slow burster". Our aim is to study the connection between the persistent X-ray spectra and the X-ray burst spectra in a broad spectral range. Methods. We performed spectral modeling of the persistent emission and the X-ray burst emission of 4U 1728-34 using data from the INTEGRAL JEM-X and IBIS/ISGRI instruments. Results. We constructed a hardness intensity diagram to track spectral state variations. In the soft state the energy spectra are characterized by two thermal components - likely from the accretion disc and the boundary/spreading layer - together with a weak hard X-ray tail that we detect in 4U 1728-34 for the first time in the 40 to 80 keV range. In the hard state the source is detected up to 200 keV and the spectrum can be described by a thermal Comptonization model plus an additional component: either a powerlaw tail or reflection. By stacking 123 X-ray bursts in the hard state, we detect emission up to 80 keV during the X-ray bursts. We find that during the bursts the emission above 40 keV decreases by a factor of about three with respect to the persistent emission level. Conclusions. Our results suggest that the enhanced X-ray burst emission changes the spectral properties of the accretion disc in the hard state. The likely cause is an X-ray burst induced cooling of the electrons in the inner hot flow near the neutron star.Comment: 7 pages, 5 figures, Accepted for publication in A&

Natural origin products as a source of new antiviral molecules

Motivation: Human adenovirus (HAdV) is a DNA virus that can cause a wide range of diseases, including respiratory and gastrointestinal infections, or conjunctivitis, that in immunocompetent individuals are ausually mild and self-limited. However, in immunosuppresed people and especially in pediatric units, HAdV infections present high morbidity and mortality. Currently there is no specific treatment approved against HAdV. The aim of this work was to characterize the anti-HAdV activity of 18 compounds that were previously selected after high-troughput screening (HTP) of a library of 1340 compounds, coming from our collaboration with the European initiative COSTACTION CM 1407Methods: We had evaluated the anti-HAdV activity of the compounds performing in vitro assays: plaque assays to calculate the IC50 value, citotoxicity assays to calculate the CC50 value, yield reduction assays and qPCR in real time to evaluate the inhibitory effect, and nucleocitoplasm assays to evaluate their mechanism of action.Results: It has been proven that 2 compounds, BBN75 and GSAED772E-1S2R have a safe selectivity index, a great inhibitory effect and they may act in steps subsequent to the arrival of the viral genome at the nucleus of the host cell.Conclusions: The results indicates that BBN75 and GSAED772E-1S2R are promising anti-HAdV drugs to be evaluated at in vivo assays

ITQMM: a new model for IT processes

Information Technology (IT) Governance and IT Service and Processes Management (ITSM) are one of the priorities in organizations. Although many organizations are aware of the importance of using well-defined quality IT processes, they face the problem of how to use and improve them in practice. One of the final objectives of any ITSM policy must be to guarantee an adequate IT quality. In this sense, the use of action frameworks as Information Technology Infrastructure Library (ITIL) is essential. However, several quality models and maturity models have been developed, but they are not focused on how to measure the IT quality. As they do not include the appropriate mechanisms, it is necessary to complement them with other quality frameworks, e.g. European Foundation for Quality Management (EFQM). This paper proposes a maturity model for IT quality improvement based mainly on ITIL and EFQM

Robust symmetric multiplication for programmable analog VLSI array processing

This paper presents an electrically programmable analog multiplier. The circuit performs the multiplication between an input variable and an electrically selectable scaling factor. The multiplier is divided in several blocks: a linearized transconductor, binary weighted current mirrors and a differential to single-ended current adder. This paper shows the advantages introduced using a linearized OTA-based multiplier. The circuit presented renders higher linearity and symmetry in the output current than a previously reported single-transistor multiplier. Its inclusion in an array processor based on CNN allows for a more accurate implementation of the processing model and a more robust weight distribution scheme than those found in previous designs.Office of Naval Research (USA) N-00014- 02-1-0884Ministerio de Ciencia y Tecnología TIC2003-09817-C02-0