422 research outputs found

    The INTEGRAL-OMC Scientific Archive

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    The Optical Monitoring Camera (OMC) on-board the INTEGRAL satellite has, as one of its scientific goals, the observation of a large number of variable sources previously selected. After almost 6 years of operations, OMC has monitored more than 100 000 sources of scientific interest. In this contribution we present the OMC Scientific Archive (http://sdc.laeff.inta.es/omc/) which has been developed to provide the astronomical community with a quick access to the light curves generated by this instrument.We describe the main characteristics of this archive, as well as important aspects for the users: object types, temporal sampling of light curves and photometric accuracy.Comment: 4 pages, 5 figures. "Highlights of Spanish Astrophysics V" Proceedings of the VIII Scientific Meeting of the Spanish Astronomical Society (SEA) held in Santander, July 7-11, 200

    HIMMO - A lightweight collusion-resistant key predistribution scheme

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    In this paper we introduce HIMMO as a truly practical and lightweight collusion-resistant key predistribution scheme. The scheme is reminiscent ofBlundo et al\u27s elegant key predistribution scheme, in which the master key is a symmetric bivariate polynomial over a finite field, and a unique common key is defined for every pair of nodes as the evaluation of the polynomial at the finite field elements associated with the nodes. Unlike Blundo et al\u27s scheme, however, which completely breaks down once the number of colluding nodes exceeds the degree of the polynomial, the new scheme is designed to tolerateany number of colluding nodes. Key establishment in HIMMO amounts to the evaluation of a single low-degree univariate polynomial involving reasonably sized numbers, thus exhibiting excellent performance even for constrained devices such as 8-bit CPUs, as we demonstrate. On top of this, the scheme is very versatile, as it not only supports implicit authentication of the nodes like any key predistribution scheme, but also supports identity-based key predistribution in a natural and efficient way. The latter property derives from the fact that HIMMO supports long node identifiers at a reasonable cost, allowing outputs of a collision-resistant hash function to be used as node identifiers. Moreover, HIMMO allows for a transparent way to split the master key between multiple parties. The new scheme is superior to any of the existing alternatives due to the intricate way it combines the use of multiple symmetric bivariate polynomials evaluated over ``different\u27\u27 finite rings. We have extensively analyzed the security of HIMMO against two attacks. For these attacks, we have identified the Hiding Information (HI) problem and the Mixing Modular Operations (MMO) problem as the underlying problems. These problems are closely related to some well-defined lattice problems, and therefore the best attacks on HIMMO are dependent on lattice-basis reduction. Based on these connections, we propose concrete values for all relevant parameters, for which we conjecture that the scheme is secure

    Effect of amount of doping agent on sintering, microstructure and optical properties of Zr- and La-doped alumina sintered by SPS

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    SPS-produced α-alumina samples are prepared from powders doped with different amounts of Zr4+ and La3+ cations. Zr4+ cations segregate at grain boundaries. m-ZrO2 particles are formed at 570 but not at 280 cat ppm. A ÎČ-alumina LaAl11O18 structure is found at 310 cat ppm when the lanthanum grain boundary solubility limit is exceeded (∌200 cat ppm). 100 cat ppm La is sufficient to block the diffusion path across grain boundaries and inhibit grain growth. Both doping cations disturb the grain boundary diffusion whatever their amount. They delay the densification at higher temperatures while limiting grain growth. The real in-line transmittance (RIT) of α-alumina is improved due to the reduced grain size. Nevertheless, increasing the cation amount leads to an increase in porosity or even the formation of secondary phase particles, both detrimental for optical properties. Finally, optimised amounts of cation of 200 and 150 cat ppm are found for La- and Zr-doped alumina, respectively

    Attacks and parameter choices in HIMMO

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    The HIMMO scheme has been introduced as a lightweight collusion-resistant key pre-distribution scheme, with excellent efficiency in terms of bandwidth, energy consumption and computation time. As its cryptanalysis relies on lattice techniques, HIMMO is also an interesting quantum-safe candidate. Unlike the schemes by Blom, by Matsumoto and Imai, and by Blundo {\em et al}, which break down once the number of colluding nodes exceeds a given threshold, it aims at tolerating any number of colluding nodes. In 2015, a contest for the verification of the scheme was held. During the contest, a method was developed to guess a key by finding an approximate solution of one of the problems underlying the scheme. This attack involves finding a short vector in a lattice of dimension linear in a system parameter α\alpha and allowed key recovery for several challenges. Thwarting this attack by increasing α\alpha would lead to a significant performance degradation, as CPU and memory requirements for the implementation of the scheme scale quadratically in α\alpha. This paper describes a generalization of HIMMO parameters that allows configuring the scheme such that both its performance and the dimension of the lattice involved in the attack grow linearly in α\alpha. Two attacks inspired by the one developed in the contest are described, and the impact of those attacks for different parameter choices is discussed. Parameters choices are described that thwart existing attacks while enabling high performance implementations of the scheme

    Impact of pre- and/or post-autologous stem cell transplantation exposure to brentuximab vedotin on survival outcomes in patients with high-risk Hodgkin lymphoma

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    The AETHERA trial demonstrated that brentuximab vedotin (BV) consolidation after autologous stem cell transplantation (ASCT) in patients with Hodgkin lymphoma (HL) at high risk of relapse/progression increases progression-free survival (PFS). Patients previously exposed to BV were excluded from that trial. However, BV alone or in combination with chemotherapy is frequently used as front-line treatment and/or pre-ASCT salvage therapy. We analyzed data from 156 patients with high-risk HL who underwent ASCT with (BV-CON, n?=?62) or without (non-BV, n?=?94) BV consolidation. Fifty-seven patients received BV-based salvage regimens before ASCT. The 3-year overall survival and PFS for all patients were 91.6% and 70.0%, respectively. Multivariate analysis showed that BV-CON was associated with better PFS (HR 0.39, p?=?0.01), whereas positive PET at transplant leaded to worse PFS (HR 2.71, p?=?0.001). BV-CON improved PFS in PET-positive patients (72.2% vs. 43.0%, p?=?0.05), with a beneficial trend observed in PET negative (88.8% vs. 75.2%, p?=?0.09). BV-CON patients with or without BV exposure pre-ASCT had a significantly better PFS than non-BV with or without BV pretransplant treatment (HR 0.36, p?=?0.004). The efficacy of real-life BV consolidation therapy was similar to that in the AETHERA trial. This therapeutic strategy improves survival independently of BV exposure prior to ASCT.© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature

    Differential body composition effects of protease inhibitors recommended for initial treatment of HIV infection: A randomized clinical trial

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    This article has been accepted for publication in Clinical Infectious Diseases ©2014 The Authors .Published by Oxford University Press on Clinical Infectious Disease 60.5. DOI: 10.1093/cid/ciu898Background. It is unclear whether metabolic or body composition effects may differ between protease inhibitor-based regimens recommended for initial treatment of HIV infection. Methods. ATADAR is a phase IV, open-label, multicenter randomized clinical trial. Stable antiretroviral-naive HIV-infected adults were randomly assigned to atazanavir/ritonavir 300/100 mg or darunavir/ritonavir 800/100 mg in combination with tenofovir/emtricitabine daily. Pre-defined end-points were treatment or virological failure, drug discontinuation due to adverse effects, and laboratory and body composition changes at 96 weeks. Results. At 96 weeks, 56 (62%) atazanavir/ritonavir and 62 (71%) darunavir/ritonavir patients remained free of treatment failure (estimated difference 8.2%; 95%CI -0.6 to 21.6); and 71 (79%) atazanavir/ritonavir and 75 (85%) darunavir/ritonavir patients remained free of virological failure (estimated difference 6.3%; 95%CI -0.5 to 17.6). Seven vs. five patients discontinued atazanavir/ritonavir or darunavir/ritonavir due to adverse effects. Total and HDL cholesterol similarly increased in both arms, but triglycerides increased more in atazanavir/ritonavir arm. At 96 weeks, body fat (estimated difference 2862.2 gr; 95%CI 726.7 to 4997.7; P=0.0090), limb fat (estimated difference 1403.3 gr; 95%CI 388.4 to 2418.2; P=0.0071), and subcutaneous abdominal adipose tissue (estimated difference 28.4 cm2; 95%CI 1.9 to 55.0; P=0.0362) increased more in atazanavir/ritonavir than in darunavir/ritonavir arm. Body fat changes in atazanavir/ritonavir arm were associated with higher insulin resistance. Conclusions. We found no major differences between atazanavir/ritonavir and darunavir/ritonavir in efficacy, clinically-relevant side effects, or plasma cholesterol fractions. However, atazanavir/ritonavir led to higher triglycerides and total and subcutaneous fat than darunavir/ritonavir and fat gains with atazanavir/ritonavir were associated with insulin resistanceThis is an Investigator Sponsored Research study. It was supported in part by research grants from Bristol‐Myers Squibb and Janssen‐Cilag; Instituto de Salud Carlos III (PI12/01217) and Red TemĂĄtica Cooperativa de InvestigaciĂłn en SIDA G03/173 (RIS‐EST11), Ministerio de Ciencia e InnovaciĂłn, Spain. (Registration number: NCT01274780; registry name: ATADAR; EUDRACT; 2010‐021002‐38)

    X chromosome inactivation does not necessarily determine the severity of the phenotype in Rett syndrome patients

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    Rett syndrome (RTT) is a severe neurological disorder usually caused by mutations in the MECP2 gene. Since the MECP2 gene is located on the X chromosome, X chromosome inactivation (XCI) could play a role in the wide range of phenotypic variation of RTT patients; however, classical methylation-based protocols to evaluate XCI could not determine whether the preferentially inactivated X chromosome carried the mutant or the wild-type allele. Therefore, we developed an allele-specific methylation-based assay to evaluate methylation at the loci of several recurrent MECP2 mutations. We analyzed the XCI patterns in the blood of 174 RTT patients, but we did not find a clear correlation between XCI and the clinical presentation. We also compared XCI in blood and brain cortex samples of two patients and found differences between XCI patterns in these tissues. However, RTT mainly being a neurological disease complicates the establishment of a correlation between the XCI in blood and the clinical presentation of the patients. Furthermore, we analyzed MECP2 transcript levels and found differences from the expected levels according to XCI. Many factors other than XCI could affect the RTT phenotype, which in combination could influence the clinical presentation of RTT patients to a greater extent than slight variations in the XCI pattern

    Opposite-side flavour tagging of B mesons at the LHCb experiment

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    The calibration and performance of the oppositeside flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B + →J/ψK +, B0 →J/ψK ∗0 and B0 →D ∗− ÎŒ + ΜΌ decay modes with 0.37 fb−1 of data collected in pp collisions at √ s = 7 TeV during the 2011 physics run. The oppositeside tagging power is determined in the B + → J/ψK + channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty is statistical and the second is systematic
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