Physical Sciences and Mathematics Commons^™

The Xmm-Newton Epic X-Ray Light Curve Analysis Of Wr 6., Richard Ignace, K. Gayley, W.-R. Hamann, D. Huenemoerder, L. Oskinova, A. Pollock, M. Mcfall

ETSU Faculty Works

We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 d period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for "event clustering" in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays …

Associations Of Smoking Status And Serious Psychological Distress With Chronic Obstructive Pulmonary Disease, Ke-Sheng Wang, Liang Wang, Shimin Zheng, Long-Yang Wu

ETSU Faculty Works

Background: Chronic obstructive pulmonary disease (COPD) has been a major public health problem due to its high prevalence, morbidity, and mortality. Smoking is a major risk factor for COPD, while serious psychological distress (SPD) is prevalent among COPD patients. However, no study focusing on the effect of SPD on COPD has been so far conducted, while few studies have focused on the associations of SPD and behavioral factors with COPD by smoking status.

Objectives: This study aimed to examine the associations of SPD and behavioral factors (such as smoking and physical activity) with COPD.

Materials and Methods: Weighted logistic regression …

Self-Assessment And Student Improvement In An Introductory Computer Course At The Community College Level, Jama Spicer-Sutton, James Lampley, Donald W. Good

ETSU Faculty Works

Excerpt:The purpose of this study was to determine a student’s computer knowledge upon course entry and if there was a difference in college students’ improvement scores as measured by the difference in pretest and post‐test scores of new or novice users, moderate users, and expert users at the end of a college level introductory computing class.

Faraday Rotation Distributions From Stellar Magnetism In Wind-Blown Bubbles., Richard Ignace, N. Pingel

ETSU Faculty Works

Faraday rotation is a valuable tool for detecting magnetic fields. Here, the technique is considered in relation to wind-blown bubbles. In the context of spherical winds with azimuthal or split monopole stellar magnetic field geometries, we derive maps of the distribution of position angle (P.A.) rotation of linearly polarized radiation across projected bubbles. We show that the morphology of maps for split monopole fields are distinct from those produced by the toroidal field topology; however, the toroidal case is the one most likely to be detectable because of its slower decline in field strength with distance from the star. We …

A Report On The X-Ray Properties Of The Τ Sco Class Of Stars., Richard Ignace, L. Oskinova, D. Massa

ETSU Faculty Works

An increasing number of OB stars have been shown to possess magnetic fields. Although the sample remains small, it is surprising that the magnetic and X-ray properties of these stars appear to be far less correlated than expected. This contradicts model predictions, which generally indicate that the X-rays from magnetic stars are harder and more luminous than their non-magnetic counterparts. Instead, the X-ray properties of magnetic OB stars are quite diverse. τ Sco is one example where the expectations are better met. This bright main-sequence, early B star has been studied extensively in a variety of wavebands. It has a …

Investigating The Spectroscopic, Magnetic And Circumstellar Variability Of The O9 Subgiant Star Hd 57682., J. Grunhut, G. Wade, J. Sundqvist, A. Ud-Doula, C. Neiner, Richard Ignace, W. Marcolino, Th. Rivinius, A. Fullerton, L. Kaper, B. Mauclaire, C. Buil, T. Garrel, J. Ribeiro, S. Ubaud

ETSU Faculty Works

The O9IV star HD 57682, discovered to be magnetic within the context of the Magnetism in Massive Stars (MiMeS) survey in 2009, is one of only eight convincingly detected magnetic O-type stars. Among this select group, it stands out due to its sharp-lined photospheric spectrum. Since its discovery, the MiMeS Collaboration has continued to obtain spectroscopic and magnetic observations in order to refine our knowledge of its magnetic field strength and geometry, rotational period and spectral properties and variability. In this paper we report new Echelle SpectroPolarimetric Device for the Observation of Stars (ESPaDOnS) spectropolarimetric observations of HD 57682, which …

Discovery Of A Magnetic Field In The Rapidly-Rotating O-Type Secondary Of The Colliding-Wind Binary Hd 47129 (Plaskett’S Star)., J. Grunhut, G. Wade, M. Leutenegger, V. Petit, G. Rauw, C. Neiner, F. Martins, D. Cohen, M. Gagné, Richard Ignace, S. Mathis, S. De Mink, A. Moffat, S. Owocki, M. Shultz, J. Sundqvist, Mimes Collaboration

ETSU Faculty Works

We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star) in the context of the Magnetism in Massive Stars survey. Eight independent Stokes V observations were acquired using the Echelle SpectroPolarimetric Device for the Observations of Stars (ESPaDOnS) spectropolarimeter at the Canada–France–Hawaii Telescope and the Narval spectropolarimeter at the Télescope Bernard Lyot. Using least-squares deconvolution we obtain definite detections of signal in Stokes V in three observations. No significant signal is detected in the diagnostic null (N) spectra. The Zeeman signatures are broad and …

Moments Of Matrix Variate Skew Elliptically Contoured Distributions, Shimin Zheng, Jeff Knisley, Chunming Zhang

ETSU Faculty Works

Matrix variate skew elliptically contoured distributions generalize several classes of important distributions. This paper defines and explores matrix variate skew elliptically contoured distributions. In particular, we discuss the first two moments of the matrix variate skew elliptically contoured distributions.

Stochastic Representations Of The Matrix Variate Skew Elliptically Contoured Distributions, Shimin Zheng, Chunming Zhang, Jeff Knisley

ETSU Faculty Works

Matrix variate skew elliptically contoured distributions generalize several classes of important distributions. This paper defines and explores matrix variate skew elliptically contoured distributions. In particular, we discuss two stochastic representations of the matrix variate skew elliptically contoured distributions.

Predictors Of Treatments Acceptable To Patients For Late-Life Depression, Gerald J. Jogerst, Shimin Zheng, Erik Vanderlip

ETSU Faculty Works

Objectives. Describe older patients’ perceptions about depression and characteristics associated with acceptance of treatments. Design. Cross-sectional study. Setting. Three primary care clinics in Iowa. Participants. Consecutive sample of 529 primary care patients. Measurements. Depression screening tool (a 9-item patient health questionnaire [PHQ-9]) and questionnaire including sociodemographic data, patient attitudes about depression, and acceptability of different treatments. Results. Mean age was 71.9 years (range 60–93 years), 314 (59%) female. Among the 529 participants, 93 (17.5%) had history of depression and 60 (11.3%) had PHQ-9 scores of 10 or greater. Participants believed depression is a disease for which they would use medication …

Screening For Elder Mistreatment Among Older Adults Seeking Legal Assistance Services, Sheryl M. Strasser, Megan Smith, Scott Weaver, Shimin Zheng, Yan Cao

ETSU Faculty Works

Introduction: The aging population is a rapidly growing demographic in the United States. Isolation, limited autonomy, and declining physical and mental health render many older adults vulnerable to elder mistreatment (EM). The purpose of this study was to assess the prevalence and correlates of EM among a sample of older adults using legal assistance services in Atlanta, Georgia.

Methods: Researchers administered surveys to consenting older adults (aged 60þ) in 5 metro Atlanta community centers that hosted legal assistance information sessions as part of the Elderly Legal Assistance Program. The surveys screened for risk factors and prevalence of EM risk using …