Binary Slowly Pulsating B Stars

AbstractThe satellite Hipparcos led to the discovery of 267 new variable B-type stars. Some 100 of them were classified as candidate slowly pulsating B stars (SPBs) by Waelkens et al. (1998). Twelve of the brightest southern candidate SPBs were selected together with 5 confirmed SPBs to start a long-term follow-up study (Aerts et al. 1999). From 1996 up to 1998, numerous high-resolution, high signal-to-noise spectra were taken with the CAT/CES combination at La Silla in order to study the line profile variations of the Si II-doublet centered at 4130 Å.We report our finding that at least 8 of 17 targets turn out to be spectroscopic binaries. We have found a large variety in the obtained orbits. HD 123515 and HD 140873 were known as single-lined spectroscopic binaries, but both turn out to be double-lined. All the others binaries are single-lined. For HD 140873 and HD 177863, we find orbits with large eccentricities of respectively e = 0.731 α 0.006 and e = 0.603 α 0.007. HD 69144, HD 92287 and HD 169978 are three binaries with circular orbits and very short orbital periods (a few days). Since their photometric measurements are dominated by (close to) sinusoidal variations with twice the orbital frequency, these stars are ellipsoidal variables. Their orbital periods are of the same order of magnitude as the expected periods of pulsation.After removing the orbit, we find the same first frequency in the residual radial velocities as in the gathered photometric measurements for 6 stars. For HD 69144 and HD 169978 we did not yet succeed in deriving an intrinsic period, although HD 69144 has prominent line profile variations. For HD 169978, we have serious doubts about the SPB nature.For a detailed description, we refer to De Cat et al. (1999).

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Long-Term Photometric and Spectroscopic Monitoring of Slowly Pulsating B Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100058188 ◽

2000 ◽

Vol 176 ◽

pp. 394-400

Author(s):

C. Aerts ◽

P. De Cat ◽

J. De Ridder ◽

K. Kolenberg ◽

C. Waelkens ◽

...

Keyword(s):

Current Data ◽

Spectroscopic Binaries ◽

Current Status ◽

Pulsation Period ◽

B Stars ◽

Spectroscopic Monitoring ◽

Long Term Follow Up ◽

Order Of Magnitude ◽

Almost All

AbstractWe review the current status of our long-term monitoring project on slowly pulsating B stars that we started in the course of 1996 and that was recently completed as far as the first part of our plan is concerned. In total, we have selected 17 southern and 8 northern stars. The idea is to fully exploit our current data in the near future and to select the most interesting targets for further very-long-term follow-up monitoring. A first conclusion is that half of the southern targets turn out to be spectroscopic binaries. Some of these have circular orbits and periods of the same order of magnitude as the intrinsic pulsation period(s) of the primary. The eccentric binaries have periods ranging from 12 to 460 d. For most stars the photometric behaviour is dominated by the same frequency as the intrinsic spectroscopic variability. Multiperiodicity in the expected frequency range is found for almost all stars. Two objects, however, turn out to have only one dominant pulsation mode.

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Arterial spin labeling perfusion-weighted MRI for long-term follow-up of a cerebral arteriovenous malformation after stereotactic radiosurgery

Acta Radiologica Short Reports ◽

10.1177/2047981613510160 ◽

2014 ◽

Vol 3 (1) ◽

pp. 204798161351016 ◽

Cited By ~ 3

Author(s):

Kazuhiro Shimizu ◽

Nobuyuki Kosaka ◽

Tatsuya Yamamoto ◽

Hiroki Shioura ◽

Toshiaki Kodera ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Arterial Spin Labeling ◽

Spin Labeling ◽

High Signal ◽

Non Invasive ◽

Signal Abnormality ◽

Complete Obliteration ◽

Long Term Follow Up

We present a longitudinal series of arterial spin-labeling magnetic resonance imaging (ASL-MRI) in a patient with cerebral arteriovenous malformations (AVMs) treated by stereotactic radiosurgery (SRS). Pretreatment ASL-MRI showed high signal intensity in both the nidus and draining veins, and the latter signal abnormality gradually moved proximally by 14 months after SRS. At 24 months, the signal abnormalities finally disappeared, indicating complete obliteration of the nidus. The hemodynamic changes in the AVM were clearly visualized in the longitudinal ASL-MRI series, thus this non-invasive MR method may be useful not only for detecting AVMs but also for assessment of their response after SRS.

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Spectroscopic binaries RV Tauri and DF Cygni

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834956 ◽

2019 ◽

Vol 628 ◽

pp. A40 ◽

Cited By ~ 2

Author(s):

Rajeev Manick ◽

Devika Kamath ◽

Hans Van Winckel ◽

Alain Jorissen ◽

Sanjay Sekaran ◽

...

Keyword(s):

Orbital Period ◽

Asymptotic Giant Branch ◽

Spectroscopic Binaries ◽

Spectral Energy ◽

Pulsation Frequency ◽

Photometric Variability ◽

Orbital Inclination ◽

Orbital Periods ◽

The Impact

Context. Some RV Tauri stars show a long-term photometric variability in their mean magnitudes. DF Cygni (DF Cyg), the only RV Tauri star in the original Kepler field, and the prototype RV Tauri (RV Tau) are two such stars. Aims. The focus of this paper is on two famous but still poorly understood RV Tauri stars: RV Tau and DF Cyg. We aim to confirm their suspected binary nature and derive their orbital elements to investigate the impact of their orbits on the evolution of these systems. This research is embedded in a wider endeavour to study binary evolution of low- and intermediate-mass stars. Methods. The high amplitude pulsations were cleaned from the radial-velocity data to better constrain the orbital motion, allowing us to obtain accurate orbital parameters. We also analysed the photometric time series of both stars using a Lomb-Scargle periodogram. We used Gaia Data Release 2 (DR2) parallaxes in combination with the spectral energy distributions (SEDs) to compute their luminosities. These luminosities were complemented with the ones we computed using a period-luminosity-colour (PLC) relation for RV Tauri stars. The ratio of the circumstellar infrared (IR) flux to the photospheric flux obtained from the SEDs was used to estimate the orbital inclination of each system. Results. DF Cyg and RV Tau are binaries with spectroscopic orbital periods of 784 ± 16 days and 1198 ± 17 days, respectively. These orbital periods are found to be similar to the long-term periodic variability in the photometry, indicating that binarity indeed explains the long-term photometric variability. The SEDs of these systems indicate the presence of a circumbinary disc. Our line of sight grazes the dusty disc, which causes the photometric flux from the star to extinct periodically with the orbital period. Our derived orbital inclinations enabled us to obtain accurate companion masses for DF Cyg and RV Tau, and these were found to be 0.6 ± 0.1 M⊙ and 0.7 ± 0.1 M⊙, respectively. The derived luminosities suggest that RV Tau is a post asymptotic giant branch (post-AGB) binary, while DF Cyg is likely a post red giant branch (post-RGB) binary. Analysis of the Kepler photometry of DF Cyg revealed a power spectrum with side lobes around the fundamental pulsation frequency. This modulation corresponds to the spectroscopic orbital period and hence to the long-term photometric period. Finally we report on the evidence of high velocity absorption features related to the Hα profile in both objects, indicating outflows launched from around the companion.

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Double stars: a synergy between amateur and professional astronomers

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311003528 ◽

2009 ◽

Vol 5 (S260) ◽

Author(s):

Jean-Louis Agati ◽

Daniel Bonneau ◽

Sébastien Caille ◽

Paul Couteau ◽

André Debackère ◽

...

Keyword(s):

Double Stars ◽

Visual Double Stars ◽

Long Term Follow Up ◽

Orbital Periods

AbstractIn the field of visual double stars, a long term follow-up is required, since their orbital periods may reach several centuries. Created in 1981 within the Société Astronomique de France (SAF) with the support of the late Paul Muller (1910-2000), the Commission des Etoiles Doubles provides the framework for the necessary collaboration between professional and amateur astronomers, through generations. The late Dr. Paul Baize (1901-1995) was a model for its members. Several professional astronomers became scientific advisors of the Commission and have guided many works made by amateurs.

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Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

Behavioral and Brain Sciences ◽

10.1017/s0140525x1800105x ◽

2019 ◽

Vol 42 ◽

Cited By ~ 2

Author(s):

John P. A. Ioannidis

Keyword(s):

Mental Health ◽

Mental Disease ◽

Brain Disorders ◽

Social Stressors ◽

Labor Education ◽

Mental Diseases ◽

Long Term Follow Up ◽

Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

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Continuous Positive Airway Pressure (CPAP) Therapy for the Treatment of Hypernasality: A Single Case Study

Perspectives on Speech Science and Orofacial Disorders ◽

10.1044/ssod24.2.48 ◽

2014 ◽

Vol 24 (2) ◽

pp. 48-58 ◽

Cited By ~ 3

Author(s):

Lakshmi Kollara ◽

Graham Schenck ◽

Jamie Perry

Keyword(s):

Continuous Positive Airway Pressure ◽

Airway Pressure ◽

Positive Airway Pressure ◽

Single Case ◽

Treatment Method ◽

Post Treatment ◽

Subjective Perception ◽

Cpap Therapy ◽

Long Term Follow Up

Studies have investigated the applications of Continuous Positive Airway Pressure (CPAP) therapy in the treatment of hypernasality due to velopharyngeal dysfunction (VPD; Cahill et al., 2004; Kuehn, 1991; Kuehn, Moon, & Folkins, 1993; Kuehn et al., 2002). The purpose of this study was to examine the effectiveness of CPAP therapy to reduce hypernasality in a female subject, post-traumatic brain injury (TBI) and pharyngeal flap, who presented with signs of VPD including persistent hypernasality. Improvements in mean velopharyngeal orifice size, subjective perception of hypernasality, and overall intelligibility were observed from the baseline to 8-week post-treatment assessment intervals. Additional long-term assessments completed at 2, 3, and 4 months post-treatment indicated decreases in immediate post-treatment improvements. Results from the present study suggest that CPAP is a safe, non-invasive, and relatively conservative treatment method for reduction of hypernasality in selected patients with TBI. More stringent long-term follow up may indicate the need for repeated CPAP treatment to maintain results.

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