522 research outputs found

    Migraine-specific quality of life questionnaire and relapse on medication overuse headache

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    Background: The management of Medication overuse headache (MOH) represents a difficult challenge for clinicians and headache experts, particularly for the responder rate after a successful withdrawal treatment. The purpose of this study was to investigate the role of demographic and clinical characteristics as well as the score of Migraine-Specific Quality of Life Questionnaire (MSQ), Migraine Disability Questionnaire and Leeds Dependence Questionnaire in predicting a response after a successful withdrawal treatment in patients with MOH. Methods: This ancillary study is part of a randomized trial that demonstrated the safety and the efficacy of a 3-month treatment with sodium valproate (VPA) (800 mg/day vs placebo) in MOH. Demographic and clinical characteristics and questionnaire results were obtained from the entire sample. Results: A significant correlation was found only between MOH relapse and the total MSQ score, the Role Preventive sub-scale and the Emotional Function sub-scale, suggesting a poorer quality of life in non responders. Conclusion: A high MSQ score could be associated with a poor short-term outcome in MOH patients after a successful treatment with detoxification followed by a new treatment

    Discovery of CH and OH in the -513 km s-1 Ejecta of Eta Carinae

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    The very massive star, Eta Carinae, is enshrouded in an unusual complex of stellar ejecta, which is highly depleted in C and O, and enriched in He and N. This circumstellar gas gives rise to distinct absorption components corresponding to at least 20 different velocities along the line-of-sight. The velocity component at -513 kms-1 exhibits very low ionization with predominantly neutral species of iron-peak elements. Our statistical equilibrium/photoionization modeling indicates that the low temperature (T = 760 K) and high density (n_H=10^7 cm^-3) of the -513 kms-1 component is conducive to molecule formation including those with the elements C and O. Examination of echelle spectra obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the confirms the model's predictions. The molecules, H_2, CH, and most likely OH, have been identified in the -513 kms-1 absorption spectrum. This paper presents the analysis of the HST/STIS spectra with the deduced column densities for CH, OH and C I, and upper limit for CO. It is quite extraordinary to see molecular species in a cool environment at such a high velocity. The sharp molecular and ionic absorptions in this extensively CNO- processed material offers us a unique environment for studying the chemistry, dust formation processes, and nucleosynthesis in the ejected layers of a highly evolved massive star.Comment: tentatively scheduled for the ApJ 1 September 2005, v630, 1 issu

    Bardeen-Petterson effect and the disk structure of the Seyfert galaxy NGC 1068

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    VLBA high spatial resolution observations of the disk structure of the active galactic nucleus NGC 1068 has recently revealed that the kinematics and geometry of this AGN is well characterized by an outer disk of H2O maser emission having a compact milliarcsecond (parsec) scale structure, which is encircling a thin rotating inner disk surrounding a ~10^7 M_\sun compact mass, likely a black hole. A curious feature in this source is the occurrence of a misalignment between the inner and outer parts of the disk, with the galaxy's radio jet being orthogonal to the inner disk. We interpret this peculiar configuration as due to the Bardeen-Petterson effect, a general relativistic effect that warps an initially inclined (to the black hole equator) viscous disk, and drives the angular momentum vector of its inner part into alignment with the rotating black hole spin. We estimate the time-scale for both angular momenta to get aligned as a function the spin parameter of the Kerr black hole. We also reproduce the shape of the parsec and kiloparsec scale jets, assuming a model in which the jet is precessing with a period and aperture angle that decrease exponentially with time, as expected from the Bardeen-Petterson effect.Comment: 12 pages, 3 figures, accepted for publication in The Astrophysical Journa

    Self-gravitating warped discs around supermassive black holes

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    We consider warped equilibrium configurations for stellar and gaseous disks in the Keplerian force-field of a supermassive black hole, assuming that the self-gravity of the disk provides the only acting torques. Modeling the disk as a collection of concentric circular rings, and computing the torques in the non-linear regime, we show that stable, strongly warped precessing equilibria are possible. These solutions exist for a wide range of disk-to-black hole mass ratios Md/MbhM_d/M_{bh}, can span large warp angles of up to ±∌120deg⁥\pm\sim 120\deg, have inner and outer boundaries, and extend over a radial range of a factor of typically two to four. These equilibrium configurations obey a scaling relation such that in good approximation \phidot/\Omega\propto M_d/M_{bh} where \phidot is the (retrograde) precession frequency and Ω\Omega is a characteristic orbital frequency in the disk. Stability was determined using linear perturbation theory and, in a few cases, confirmed by numerical integration of the equations of motion. Most of the precessing equilibria are found to be stable, but some are unstable. The main result of this study is that highly warped disks near black holes can persist for long times without any persistent forcing other than by their self-gravity. The possible relevance of this to galactic nuclei is briefly discussed.Comment: 13 pages, 21 figures, published in MNRA

    Newly described clinical and immunopathological feature of dermatitis herpetiformis.

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    Dermatitis herpetiformis (DH) is an inflammatory cutaneous disease with typical histopathological and immunopathological findings clinically characterized by intensely pruritic polymorphic lesions with a chronic-relapsing course. In addition to classic clinical manifestations of DH, atypical variants are more and more frequently reported and histological and immunological are added to them, whereas the impact on quality of life of patients with DH is increasingly important to a certain diagnosis. The aim of this paper is to describe all the possible clinical, histological, and immunological variants of DH in order to facilitate the diagnosis of a rare disease and, therefore, little known

    Gravitational radiation from precessing accretion disks in gamma-ray bursts

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    We study the precession of accretion disks in the context of gamma-ray burst inner engines. Our aim is to quantitatively estimate the characteristics of gravitational waves produced by the precession of the transient accretion disk in gamma-ray bursts. We evaluate the possible periods of disk precession caused by the Lense-Thirring effect using an accretion disk model that allows for neutrino cooling. Assuming jet ejection perpendicular to the disk plane and a typical intrinsic time-dependence for the burst, we find gamma-ray light curves that have a temporal microstructure similar to that observed in some reported events. The parameters obtained for the precession are then used to evaluate the production of gravitational waves. We find that the precession of accretion disks of outer radius smaller than 10810^8 cm and accretion rates above 1 solar mass per second could be detected by Advanced LIGO if they occur at distances of less than 100 Mpc. We conclude that the precession of a neutrino-cooled accretion disk in long gamma-ray bursts can be probed by gravitational wave astronomy. Precession of the disks in short gamma-ray events is undetectable with the current technology.Comment: 5 pages, 5 figures, accepted for publication in A&

    Quebra de dormĂȘncia em diĂĄsporos de teca (Tectona grandis L.f.).

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    Tectona grandis L.f. Ă© uma essĂȘncia florestal exĂłtica de importĂąncia econĂŽmica e social para o Brasil. As mudas dessa espĂ©cie sĂŁo produzidas atravĂ©s de diĂĄsporos constituĂ­dos dos frutos com endocarpo e mesocarpo rĂ­gidos. O objetivo do presente trabalho foi avaliar o efeito de mĂ©todos de quebra de dormĂȘncia na germinação das sementes desta espĂ©cie. Para superar a dormĂȘncia do endocarpo e mesocarpo, os diĂĄsporos de teca foram submetidos Ă  imersĂŁo em ĂĄgua quente, imersĂŁo em ĂĄcido sulfĂșrico (33,5%) e imersĂŁo em ĂĄgua corrente. Os diĂĄsporos foram distribuĂ­dos em substrato constituĂ­do de areia, e o teste de germinação foi realizado em cĂąmara de germinação com temperatura de 30 ÂșC, sob luz branca durante oito horas por dia. As avaliaçÔes foram feitas diariamente, durante 60 dias. O mĂ©todo de imersĂŁo dos diĂĄsporos em ĂĄcido sulfĂșrico por trĂȘs minutos, foi o tratamento mais eficiente, apresentando 73% das sementes germinadas
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