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The transit of the planet orbiting HD209458 has been observed using VLT/UVES, in search for faint signatures of an extended envelope of gas possibly surrounding the planet, called exosphere. Preliminary results are shown and described. They show no evidence so far of exospheric signatures.
Luminous Blue Variables (LBVs or S Dor Variables) are showing characteristic variability of very long timescales of a decade and more. During their expansion and contraction phases, they move across a wide part of the H-R diagram with dramatic changes of their stellar wind characteristics, radius and temperature. We present results of our long-term spectroscopic monitoring campaigns for the galactic star HR Car with optical spectra taken over 13 years and two minimum and maximum phases observed during this time.
The relative abundances of elements in galaxies can provide valuable information on the stellar and chemical evolution of a galaxy. While nebulae can provide abundances for a variety of light elements, stars are the only way to directly determine the abundances of iron-group and s-process and r-process elements in a galaxy. The new 8m and 10m class telescopes and high-efficiency spectrographs now make high-quality spectral observations of bright supergiants possible in dwarf galaxies in the Local Group. We have been concentrating on elemental abundances in the metal-poor dwarf irregular galaxies, NGC 6822, WLM, Sextants A, and GR 8. Comparing abundance ratios to those predicted from their star formation histories, determined from color-magnitude diagrams, and comparing those ratios between these galaxies can give us new insights into the evolution of these dwarf irregular galaxies. Iron-group abundances also allow us to examine the metallicities of the stars in these galaxies directly, which affects their inferred mass loss rates and predicted stellar evolution properties.
We report radial velocity studies of photospheric absorption lines from spectral time series of the late O-type runaway supergiant HD 188209. Radial velocity variations with a quasi-period ∼ 2 days have been detected in high-resolution echelle spectra and most probably indicate that the supergiant is pulsating. Night-to-night variations in the position and strength of the central emission reversal of the Hα profile have been observed. The fundamental parameters of the star have been derived using state-of-the-art plane-parallel and unified non-LTE model atmospheres, these last including the mass-loss rate. The binary nature of this star is not suggested either from Hipparcos photometry or from radial-velocity curves.
We are investigating two long-period WR+O binaries, γ2 Velorum (WC8+O7.5, P = 78.5d) and WR 22 (WN7+abs+O, P = 80.3 d). We derive new orbital elements for both binaries and we give preliminary results of our analysis of the expansion velocity and ionization structure of γ2 Vel.
Extended spectroscopic monitoring programs with high resolution and coverage in wavelength and time have revealed a new picture of the winds and the circumstellar environments of late B- and early A-type supergiants. Dramatic line-profile variations (LPV) of the wind-sensitive Hα line with characteristic cyclical V/R variations indicate the presence of deviations of the envelopes from spherical symmetry. Time-series analysis of these LPVs suggest that the wind variations are caused by rotating surface structures which modulate the lower wind region. Occasionally observed high-velocity absorptions (HVA) indicate the presence of rotating extended and dense streakline or loop structures in the envelopes. The potential use of these circumstellar features to determine the true stellar rotation periods is discussed.
In this contribution the spectral characteristics, physical properties, and the evolutionary status of B-type supergiants is reviewed with respect to the Be phenomenon. Long-term monitoring campaigns in the UV and the optical have recently revealed the distinct variability patterns of the photospheric and the emission-line spectra of this class. The various proposed scenarios for the spatially structured circumstellar envelopes and their rotational modulation are presented. The possibility of generating and maintaining large-scale wind structures by photospheric processes which structure the underlying stellar surfaces is discussed. Some open questions in connection with these hypotheses will be identified.
28 Cygni was observed during two seasons spectroscopically. The radial velocities of more than 15 spectral lines were measured and searched for periodic variability. Two closely spaced periods were found. A two-dimensional analysis of the line profile variability yielded the same periods and provided the power and phase distribution across the line profiles. An outburst covered by our data coincides with the time of constructive interference of both periods. 28 Cyg is the second case for which outbursts seem to be triggered by multi-mode beating.
Spectra of the Be star 28 CMa obtained with the HEROS echelle spectrograph in 1996 and 1997 were used to check the presence of transient periods in commonly measured scalar parameters of absorption and emission lines. Transient periods can be convincingly detected in modes of higher absorption and single peak emission lines of the Balmer series as well as in the V/R ratio of Fell lines. Consequences for the frequency analyses of datasets containing radial velocities derived from different ions are discussed. The significant differences in amplitudes of radial velocities of different ions and in individual seasons were confirmed and a mean ephemeris derived.
This monograph summarizes the proceedings of a roundtable meeting convened to discuss pseudobulbar affect (PBA). Two didactic lectures were presented, followed by a moderated discussion among 11 participants. Post-meeting manuscript development synthesized didactic- and discussion-based content and incorporated additional material from the neuroscience literature. A conceptual framework with which to distinguish between disorders of mood and affect is presented first, and disorders of affect regulation are then reviewed briefly. A detailed description of the most common of these disorders, PBA, is the focus of the remainder of the monograph. The prevalence, putative neuranatomic and neurochemical bases of PBA are reviewed, and current and emerging methods of evaluation and treatment of persons with PBA are discussed. The material presented in this monograph will help clinicians better recognize, diagnose, and treat PBA, and will form a foundation for understanding and interpreting future studies of this condition.
Most patients prefer to die at home, but barely 30% do so. This study examines the variables contributing to dying at home.
The participants were 326 cancer patients, of both genders, with a mean age of 63.25 years, who died from 2000 to 2008 and were treated by the palliative care unit of the Barzilai Hospital. Some 65.7% died at home and 33.4% in a hospital. The data were extracted from patient files. The examined variables were demographic (e.g., age, gender, marital status, ethnic background, number of years in Israel until death), medical (e.g., age at diagnosis, diagnosis, nature of last treatment, patient received nursing care, patient given the care of a social worker, patient had care of a psychologist, family received care of a social worker, patient had a special caregiver), and sociological (e.g., having insurance, having worked in Israel, living alone or with family, living with one's children, living in self-owned or rented house, family members working).
The findings indicate that the chances of dying at home are higher if the patient is non-Ashkenazi, the family got social worker care, the patient lived in a self-owned house, the patient lived with his family, the family members worked, and the patient's stay in Israel since immigration was longer. Logistic regression showed that all the predictors together yielded a significant model accounting for 10.9–12.3% of the variance.
Significance of results:
The findings suggest that dying at home requires maintaining continued care for the patient and family in a community context.
This chapter presents an overview and practical approach to conceptualize manifestations of cerebellar lesions and outlines the principles that govern the cerebellar contribution to cognition and emotion as well as to sensorimotor function. Lesions of the cerebellum have been regarded as producing motor impairments. The cerebellar motor syndrome is characterized by wide-based and unsteady, or ataxic, gait; incoordination, or dysmetria, of the arms and legs; articulation impairment, or dysarthria; and eye movement abnormalities that disturb vision. The cerebellar cognitive affective syndrome (CCAS) results from lesions of the posterior lobe, characterized by clinically relevant deficits in executive function, visual spatial performance, linguistic processing, and dysregulation of affect. The connections of the cerebellum with brain circuits are implicated in psychiatric illness. Applying repetitive transcranial magnetic stimulation (TMS) to the limbic cerebellum in the vermis improves psychiatric disorders such as schizophrenia by upregulating cerebellar modulation of cerebrocerebellar circuits engaged in cognition and emotion.
The earliest cognitive deficits observed in amnestic mild cognitive impairment (aMCI) appear to center on memory tasks that require relational memory (RM), the ability to link or integrate unrelated pieces of information. RM impairments in aMCI likely reflect neural changes in the medial temporal lobe (MTL) and posterior parietal cortex (PPC). We tested the hypothesis that individuals with aMCI, as compared to cognitively normal (CN) controls, would recruit neural regions outside of the MTL and PPC to support relational memory. To this end, we directly compared the neural underpinnings of successful relational retrieval in aMCI and CN groups, using event-related functional magnetic resonance imaging (fMRI), holding constant the stimuli and encoding task. The fMRI data showed that the CN, compared to the aMCI, group activated left precuneus, left angular gyrus, right posterior cingulate, and right parahippocampal cortex during relational retrieval, while the aMCI group, relative to the CN group, activated superior temporal gyrus and supramarginal gyrus for this comparison. Such findings indicate an early shift in the functional neural architecture of relational retrieval in aMCI, and may prove useful in future studies aimed at capitalizing on functionally intact neural regions as targets for treatment and slowing of the disease course. (JINS, 2012, 18, 1–12)