538 research outputs found
Migraine-specific quality of life questionnaire and relapse on medication overuse headache
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
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
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
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 , can span large warp angles of up to ,
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 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.
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
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 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&
- …