12,523 research outputs found

    Up to date on the use of triptans for child and adolescent migraine: “the state of the art”

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    The introduction of triptans, in the early 1990s, has improved the therapy for acute migraine attack, offering a new quality of life for those patients who suffer from this disabling neurological disorder. Epidemiological data point out that about 10% of school–age children suffer from migraine, with a progressive increase in incidence and prevalence up to the threshold of adulthood. The increase in extent and prevalence of migraine from the years of growth stresses the importance of the application and adjustment of ad hoc therapeutic (either pharmacological or not) and diagnostic measures. Indeed, the peculiar neurobiological and psychological aspects which are typical of an “evolving” organism preclude the use, by simple “transposition” or “proportion”, of the knowledge acquired from adult–targeted studies. That requires the implementation of studies to analyze the specific responses of children and adolescents to the triptans. To date, the studies on such issues are absolutely insufficient to draw definitive conclusions and indications for the use of triptans for child and adolescent migraineurs

    The connection between the Galactic halo and ancient Dwarf Satellites

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    We explore the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the Milky Way have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] versus [Fe/H] patterns with the ones observed in Galactic halo stars. Oxygen abundances deviate substantially from the observed abundances in the Galactic halo stars for [Fe/H] values larger than -2 dex, while they overlap for lower metallicities. On the other hand, for the [Ba/Fe] ratio the discrepancy is extended at all [Fe/H] values, suggesting that the majority of stars in the halo are likely to have been formed in situ. Therefore, we suggest that [Ba/Fe] ratios are a better diagnostic than [O/Fe] ratios. Moreover, we show the effects of an enriched infall of gas with the same chemical abundances as the matter ejected and/or stripped from dwarf satellites of the Milky Way on the chemical evolution of the Galactic halo. We find that the resulting chemical abundances of the halo stars depend on the assumed infall time scale, and the presence of a threshold in the gas for star formation.Comment: To appear in Proceeding of Science: Frontier Research in Astrophysics - II 23-28 May 2016 Mondello (Palermo), Ital

    Heavy-Quark Probes of the Quark-Gluon Plasma at RHIC

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    Thermalization and collective flow of charm (c) and bottom (b) quarks in ultra-relativistic heavy-ion collisions are evaluated based on elastic parton rescattering in an expanding quark-gluon plasma (QGP). We show that resonant interactions in a strongly interacting QGP (sQGP), as well as the effects of parton coalescence, can play an essential role in the interpretation of recent data from the Relativistic Heavy-Ion Collider (RHIC), and thus illuminate the nature of the sQGP and its hadronization. Our main assumption, motivated by recent findings in lattice computations of Quantum Chromodynamics, is the existence of D- and B-meson states in the sQGP, providing resonant cross sections for heavy quarks up to temperatures of sim 2 T_c. Pertinent drag and diffusion coefficients are implemented into a relativistic Langevin simulation to compute transverse-momentum spectra and azimuthal asymmetries (v_2) of b- and c-quarks in Au-Au collisions at RHIC. Hadronization into D- and B-mesons is calculated from a combination of coalescence with light quarks and fragmentation, and associated electron-decay spectra and v_2 are compared to recent RHIC data. We also comment on the relative importance of radiative and elastic energy loss of heavy quarks in the QGP.Comment: 4 pages, 3 figures, v2: 1 reference updated, v3: replaced comparison to data to more recent data, references added, contents unchange

    Nonlinear equations involving the square root of the Laplacian

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    In this paper we discuss the existence and non-existence of weak solutions to parametric fractional equations involving the square root of the Laplacian A1/2A_{1/2} in a smooth bounded domain ΩRn\Omega\subset \mathbb{R}^n (n2n\geq 2) and with zero Dirichlet boundary conditions. Namely, our simple model is the following equation \begin{equation*} \left\{ \begin{array}{ll} A_{1/2}u=\lambda f(u) & \mbox{ in } \Omega\\ u=0 & \mbox{ on } \partial\Omega. \end{array}\right. \end{equation*} The existence of at least two non-trivial LL^{\infty}-bounded weak solutions is established for large value of the parameter λ\lambda requiring that the nonlinear term ff is continuous, superlinear at zero and sublinear at infinity. Our approach is based on variational arguments and a suitable variant of the Caffarelli-Silvestre extension method

    Pool temperature stratification analysis in CIRCE-ICE facility with RELAP5-3D© model and comparison with experimental tests

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    In the frame of heavy liquid metal (HLM) technology development, CIRCE pool facility at ENEA/Brasimone Research Center was updated by installing ICE (Integral Circulation Experiments) test section which simulates the thermal behavior of a primary system in a HLM cooled pool reactor. The experimental campaign led to the characterization of mixed convection and thermal stratification in a HLM pool in safety relevant conditions and to the distribution of experimental data for the validation of CFD and system codes. For this purpose, several thermocouples were installed into the pool using 4 vertical supports in different circumferential position for a total of 119 thermocouples [1][2]. The aim of this work is to investigate the capability of the system code RELAP5-3D (c) to simulate mixed convection and thermal stratification phenomena in a HLM pool in steady state conditions by comparing code results with experimental data. The pool has been simulated by a 3D component divided into 1728 volumes, 119 of which are centered in the exact position of the thermocouples. Three dimensional model of the pool is completed with a mono-dimensional nodalization of the primary main flow path. The results obtained by code simulations are compared with a steady state condition carried out in the experimental campaign. Results of axial, radial and azimuthal temperature profile into the pool are in agreement with the available experimental data Furthermore the code is able to well simulate operating conditions into the main flow path of the test section

    Class Attendance and Academic Performance among Spanish Economics Students

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    This paper presents new evidence on the effects of class attendance on academic performance. We analyse survey data collected for an Introductory Econometrics Course at the Facultad de Ciencias Sociales y Jurídicas of Universidad Carlos III de Madrid, matched to administrative data. Using OLS-proxy regressions to control for unobservable student characteristics potentially correlated with attendance, we find a positive and significant effect of attendance on academic performance. However, the fact that instrumental variable regressions may be failing to account for the correlation not captured by the controls calls for further investigation based on panel data
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