3,545 research outputs found

    Majorana neutrinos production at LHeC in an effective approach

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    We investigate the possibility of detecting Majorana neutrinos at the Large Hadron-electron Collider (LHeC), an electron-proton collision mode at CERN. We study the lj++3jetsl_j^{+} + 3 jets (lje,μ,τl_j\equiv e ,\mu ,\tau) final states which are, due to leptonic number violation, a clear signature for intermediate Majorana neutrino contributions. Such signals are not possible if the heavy neutrinos have Dirac nature. The interactions between Majorana neutrinos and the Standard Model (SM) particles are obtained from an effective lagrangian approach. We present our results for the total cross section as a function of the neutrino mass, the effective couplings and the new physics scale. We also show the discovery region as a function of the Majorana neutrino mass and the effective couplings. Our results show that the LHeC may be able to discover Majorana neutrinos with masses lower than 700700 GeV and 13001300 GeV for electron beams settings of Ee=50E_e=50 GeV and Ee=150E_e=150 GeV, respectively.Comment: 15 pages, 11 pdf figures. arXiv admin note: text overlap with arXiv:1110.095

    Inverse Low Gain Avalanche Detectors (iLGADs) for precise tracking and timing applications

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    Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 mm2mm^2; and a good timing resolution, around 20-30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100%{\%} fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented.Comment: Conference Proceedings of VCI2019, 15th Vienna Conference of Instrumentation, February 18-22, 2019, Vienna, Austri

    Medida de autocontrol motor en tiradores de esgrima mediante el Tapping Test

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    El Tapping Test es una prueba neurológica habitual en las evaluaciones de los equipos nacionales de Cuba. Nuestro objetivo fue medir el autocontrol motor con esta prueba y su respuesta psicofisiológica en deportistas de la selección nacional de esgrima de Cuba. Comparando dos versiones del Tapping Test: modo 1 (habitual de lápiz-papel) y modo 2 (versión propuesta ejecutando acción técnica con el arma). Fueron 12 participantes (Medad = 22.19 años, DE = 3.50 años). Se utilizó un equipo de registro psicofisiológico inalámbrico (Biofeedback 2000). Los resultados, indican un autocontrol motor, siendo el modo 1 significativo F(1,10) = 44.29, p < .001; ya que la cantidad de toques o golpes fueron coherentes de acuerdo al ritmo de ejecución. El modo 2 tuvo una motilidad o aceleración significativa en las diferentes fases de la prueba F(1.58,15.8) = 8.14, p = .006, además mostró un mayor nivel de activación psicofisiológica. Este grupo de esgrimistas de alto nivel a pesar del incremento en la activación mostraron un autocontrol motor, ya que controlaron su movimiento de acuerdo al ritmo que se pedía (modo 1).The Tapping Test is a common neurological means of evaluating Cuba's national teams. Our objective was to assess self-control of motor abilities and the athletes' psychophysiological response by comparing two versions of the tapping test: mode 1 (normal pencil and paper) and mode 2 (technical action with the épée). The participants were made up of 12 athletes from the Cuban National Fencing Team (Mage = 22.19 years, SD = 3.50 years). We used wireless psychophysiological recording equipment (Biofeedback 2000). The results show self-control of motor abilities, mode 1 being significant F(1,10) = 44.29, p < .001 as the number of touches or hits was consistent with the execution rate. Mode 2 showed a motility or significant acceleration in the different phases of the test F(1.586, 15.85) = 8146, p = .006, plus a higher level of psychophysiological activation. This high-ranking group of fencers demonstrated self-control of their motor abilities despite increased activation, controlling their movements to match the requested pace (mode 1)

    development of measures of polyneuropathy impairment in hattr amyloidosis from nis to mnis 7

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    Abstract Hereditary transthyretin-mediated amyloidosis (hATTR amyloidosis) is a rare, life-threatening disease, caused by point mutations in the transthyretin gene. It is a heterogeneous, multisystem disease with rapidly progressing polyneuropathy (including sensory, motor, and autonomic impairments) and cardiac dysfunction. Measures used to assess polyneuropathy in other diseases have been tested as endpoints in hATTR amyloidosis clinical trials (i.e. Neuropathy Impairment Score [NIS], NIS-lower limb, and NIS + 7), yet the unique nature of the polyneuropathy in this disease has necessitated modifications to these scales. In particular, the heterogeneous impairment and the aggressive disease course have been key drivers in developing scales that better capture the disease burden and progression of polyneuropathy in hATTR amyloidosis. The modified NIS + 7 (mNIS + 7) scale was specifically designed to assess polyneuropathy impairment in patients with hATTR amyloidosis, and has been the primary endpoint in two recent, phase III studies in this disease. The mNIS + 7 uses highly standardized, quantitative, and referenced assessments to quantify decreased muscle weakness, muscle stretch reflexes, sensory loss, and autonomic impairment. Physicians using this scale in clinical trials should be specifically trained and monitored to minimize variability. This article discusses the different scales that have been/are being used to assess polyneuropathy in patients with hATTR amyloidosis, their correlation with other disease assessments, and reflects on how and why scales have evolved to the latest iteration of mNIS + 7

    Carbon nanotubes gathered onto silica particles lose their biomimetic properties with the cytoskeleton becoming biocompatible

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    Carbon nanotubes (CNTs) are likely to transform the therapeutic and diagnostic fields in biomedicine during the coming years. However, the fragmented vision of their side effects and toxicity in humans has proscribed their use as nanomedicines. Most studies agree that biocompatibility depends on the state of aggregation/dispersion of CNTs under physiological conditions, but conclusions are confusing so far. This study designs an experimental setup to investigate the cytotoxic effect of individualized multiwalled CNTs compared to that of identical nanotubes assembled on submicrometric structures. Our results demonstrate how CNT cytotoxicity is directly dependent on the nanotube dispersion at a given dosage. When CNTs are gathered onto silica templates, they do not interfere with cell proliferation or survival becoming highly compatible. These results support the hypothesis that CNT cytotoxicity is due to the biomimetics of these nanomaterials with the intracellular nanofilaments. These findings provide major clues for the development of innocuous CNT-containing nanodevices and nanomedicines.Acknowledgments: This work was supported by the Spanish MINECO Project (references PI13/01074, PI16/00496 and CTM2014–58481-R, IDIVAL INNVAL15/15), Xunta de Galicia (Centro Singular de Investigación de Galicia-Accreditation 2016–2019 and EM2014/035), European Regional Development Fund – ERDF and Fundación Tatiana Pérez de Guzmán El Bueno

    Genetic and oceanographic tools reveal high population connectivity and diversity in the endangered pen shell Pinna nobilis

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    For marine meta-populations with source-sink dynamics knowledge about genetic connectivity is important to conserve biodiversity and design marine protected areas (MPAs). We evaluate connectivity of a Mediterranean sessile species, Pinna nobilis. To address a large geographical scale, partial sequences of cytochrome oxidase I (COI, 590 bp) were used to evaluate phylogeographical patterns in the Western Mediterranean, and in the whole basin using overlapping sequences from the literature (243 bp). Additionally, we combined (1) larval trajectories based on oceanographic currents and early life-history traits and (2) 10 highly polymorphic microsatellite loci collected in the Western Mediterranean. COI results provided evidence for high diversity and low inter-population differentiation. Microsatellite genotypes showed increasing genetic differentiation with oceanographic transport time (isolation by oceanographic distance (IBD) set by marine currents). Genetic differentiation was detected between Banyuls and Murcia and between Murcia and Mallorca. However, no genetic break was detected between the Balearic populations and the mainland. Migration rates together with numerical Lagrangian simulations showed that (i) the Ebro Delta is a larval source for the Balearic populations (ii) Alicante is a sink population, accumulating allelic diversity from nearby populations. The inferred connectivity can be applied in the development of MPA networks in the Western MediterraneanProject MEDEICG funded by the Spanish Ministry of Economy and Competitiveness (CTM2009-07013)IEH was supported by Ramon y Cajal Fellowship RYC2014-14970Spanish Ministry of Economy, Industry and Competitiveness IFCT Investigator Programme-Career Development (IF/00998/2014)MGW and AHE was supported by FCT fellowships SFRH/BPD/63703/2009 and SFRH/BPD/107878/2015National Science Foundation (OCE-1419450)CCMAR team via excellence research line EXCL/AAG-GLO/0661/2012Ciencias del Ma

    The dependence of oxygen and nitrogen abundances on stellar mass from the CALIFA survey

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    We analysed the optical spectra of HII regions extracted from a sample of 350 galaxies of the CALIFA survey. We calculated total O/H abundances and, for the first time, N/O ratios using the semi-empirical routine HII-CHI-mistry, which, according to P\'erez-Montero (2014), is consistent with the direct method and reduces the uncertainty in the O/H derivation using [NII] lines owing to the dispersion in the O/H-N/O relation. Then we performed linear fittings to the abundances as a function of the de-projected galactocentric distances. The analysis of the radial distribution both for O/H and N/O in the non-interacting galaxies reveals that both average slopes are negative, but a non-negligible fraction of objects have a flat or even a positive gradient (at least 10\% for O/H and 4\% for N/O). The slopes normalised to the effective radius appear to have a slight dependence on the total stellar mass and the morphological type, as late low-mass objects tend to have flatter slopes. No clear relation is found, however, to explain the presence of inverted gradients in this sample, and there is no dependence between the average slopes and the presence of a bar. The relation between the resulting O/H and N/O linear fittings at the effective radius is much tighter (correlation coefficient ρs\rho_s = 0.80) than between O/H and N/O slopes (ρs\rho_s = 0.39) or for O/H and N/O in the individual \hii\ regions (ρs\rho_s = 0.37). These O/H and N/O values at the effective radius also correlate very tightly (less than 0.03 dex of dispersion) with total luminosity and stellar mass. The relation with other integrated properties, such as star formation rate, colour, or morphology, can be understood only in light of the found relation with mass.Comment: Accepted for publication in A&A. 20 pages, 19 figure

    Aperture effects on the oxygen abundance determinations from CALIFA data

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    This paper aims at providing aperture corrections for emission lines in a sample of spiral galaxies from the Calar Alto Legacy Integral Field Area Survey (CALIFA) database. In particular, we explore the behavior of the log([OIII]5007/Hbeta)/([NII]6583/Halpha) (O3N2) and log[NII]6583/Halpha (N2) flux ratios since they are closely connected to different empirical calibrations of the oxygen abundances in star forming galaxies. We compute median growth curves of Halpha, Halpha/Hbeta, O3N2 and N2 up to 2.5R_50 and 1.5 disk R_eff. The growth curves simulate the effect of observing galaxies through apertures of varying radii. The median growth curve of the Halpha/Hbeta ratio monotonically decreases from the center towards larger radii, showing for small apertures a maximum value of ~10% larger than the integrated one. The median growth curve of N2 shows a similar behavior, decreasing from the center towards larger radii. No strong dependence is seen with the inclination, morphological type and stellar mass for these growth curves. Finally, the median growth curve of O3N2 increases monotonically with radius. However, at small radii it shows systematically higher values for galaxies of earlier morphological types and for high stellar mass galaxies. Applying our aperture corrections to a sample of galaxies from the SDSS survey at 0.02<=z<=0.3 shows that the average difference between fiber-based and aperture corrected oxygen abundances, for different galaxy stellar mass and redshift ranges, reaches typically to ~11%, depending on the abundance calibration used. This average difference is found to be systematically biased, though still within the typical uncertainties of oxygen abundances derived from empirical calibrations. Caution must be exercised when using observations of galaxies for small radii (e.g. below 0.5R_eff) given the high dispersion shown around the median growth curves.Comment: Accepted for publication in Ap
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