UV observations of blue stragglers and population 2 K dwarfs

Blue stragglers are stars, found usually in either open or globular clusters, that appear to lie on the main sequence, but are brighter and bluer than the cluster turn-off. Currently, two rival models are invoked to explain this apparently pathological behavior: internal mixing (so that fresh fuel is brought into the stellar core); and mass transfer (by which a normal main sequence star acquires mass from an evolving nearby companion and so moves up the main sequence). The latter model predicts that in the absence of complete mass transfer (i.e., coalescence), blue stragglers should be binary systems with the fainter star in a post-main sequence evolutionary state. It is important to ascertain the cause of this phenomenon since stellar evolution models of main sequence stars play such a vital role in astronomy. If mass transfer is involved, one may easily exclude binaries from age determinations of clusters, but if mixing is the cause, our age determinations will be much less accurate unless we can determine whether all stars or only some mix, and what causes the mixing to occur at all

The effects of an evening structured problem-solving procedure in undergraduate college students with insomnia

Worry is often reported as interfering with sleep onset and sleep maintenance, and pre-sleep cognitive arousal can persist after successful behavioral treatment of insomnia. The present investigation will examine the effects of a constructive worry procedure in an undergraduate population with impaired sleep. Thirty-three undergraduate students who reported three or more nights per week in the last month of sleep onset and/or sleep maintenance problems, either recorded worries and possible solutions (experimental CW group) or recorded worries and completed worry questionnaires (control Worry group) for five nights. As hypothesized, the CW group had decreased pre-sleep cognitive and overall arousal relative to the Worry group and relative to baseline scores. Although the CW group reported decreased cognitive arousal, there were no significant effects on somatic arousal, anxiety, Sleep Diary or actigraphy sleep variables. Suggestions for future investigations, and potential implications for the treatment of insomnia are discussed

Reevaluating the Pension System: The Struggles of Black Widows Following the Civil War

Following the Civil War, the United States government invested heavily in the U.S. Pension Bureau: a government agency that distributed monetary aid to wounded veterans. This paper discusses the impact of race and gender with regards to pensions in black communities, as evidenced by the pension files of the 34th Regiment of the South Carolina United States Colored Troops. In particular, it addresses the lack of education and documentation amongst black widows which was largely due to their enslavement, in concert with the inherent racist and sexist prejudice of white Special Examiners hired by the Pension Bureau. This combination of circumstances made it significantly more difficult for those widows to receive pensions, which were invaluable to single mothers with no other means of support. Blacks had significantly greater difficulty in attaining pensions than their black counterparts. This disparity underwrote one of the first post-emancipation means of government assistance available for African Americans. Their general disqualification from this aid through the complications of their enslavement and racism is one lost opportunity in American history to limit the race-based wealth disparity problems that still haunt the black community today

A rapid genome-wide response to Drosophila melanogaster social interactions

<p>Abstract</p> <p>Background</p> <p>The actions and reactions integral to mate recognition and reproduction are examples of multifaceted behaviors for which we are only beginning to comprehend the underlying genetic and molecular complexity. I hypothesized that social interactions, such as those involved in reproductive behaviors, would lead to immediate and assayable changes in gene expression. Such changes may have important effects on individual reproductive success and fitness through alterations in physiology or via short-term or long-term changes in nervous system function.</p> <p>Results</p> <p>I used Affymetrix <it>Drosophila</it> Genome arrays to identify genes whose expression profiles would change rapidly due to the social interactions occurring during <it>Drosophila melanogaster </it>courtship. I identified 43 loci with significant expression profile changes during a 5-min exposure period. These results indicate that social interactions can lead to extremely rapid changes in mRNA abundance.</p> <p>Conclusion</p> <p>The known functions of the up-regulated genes identified in this study include nervous system signaling and spermatogenesis, while the majority of down-regulated loci are implicated in immune signaling. Expression of two of the up-regulated genes, <it>Odorant-binding protein 99b (Obp99b) </it>and <it>female-specific independent of transformer (fit)</it>, is controlled by the <it>Drosophila</it> sex-determination gene hierarchy, which regulates male and female mating behaviors and somatic differentiation. Therefore, additional identified loci may represent other long-elusive targets of <it>Drosophila</it> sex-determination genes.</p

Space Trajectory Error Analysis Program (STEAP) for halo orbit missions. Volume 2: Programmer's manual

The six month effort was responsible for the development, test, conversion, and documentation of computer software for the mission analysis of missions to halo orbits about libration points in the earth-sun system. The software consisting of two programs called NOMNAL and ERRAN is part of the Space Trajectories Error Analysis Programs. The program NOMNAL targets a transfer trajectory from earth on a given launch date to a specified halo orbit on a required arrival date. Either impulsive or finite thrust insertion maneuvers into halo orbit are permitted by the program. The transfer trajectory is consistent with a realistic launch profile input by the user. The second program ERRAN conducts error analyses of the targeted transfer trajectory. Measurements including range, doppler, star-planet angles, and apparent planet diameter are processed in a Kalman-Schmidt filter to determine the trajectory knowledge uncertainty

Depression as a risk factor for adverse outcomes in coronary heart disease

BACKGROUND: Depression is firmly established as an independent predictor of mortality and cardiac morbidity in patients with coronary heart disease (CHD). However, it has been difficult to determine whether it is a causal risk factor, and whether treatment of depression can improve cardiac outcomes. In addition, research on biobehavioral mechanisms has not yet produced a definitive causal model of the relationship between depression and cardiac outcomes. DISCUSSION: Key challenges in this line of research concern the measurement of depression, the definition and relevance of certain subtypes of depression, the temporal relationship between depression and CHD, underlying biobehavioral mechanisms, and depression treatment efficacy. SUMMARY: This article examines some of the methodological challenges that will have to be overcome in order to determine whether depression should be regarded as a key target of secondary prevention in CHD

Child Anxiety Sensitivity in Juvenile Adolescent Twins

Child Anxiety Sensitivity in Juvenile Adolescent Twins. Researched by Laura Hazlett from the VCU Psychology Department. Help from faculty mentors Dr. John Hettema, Psychiatry and Dr. Roxann Roberson-Nay, Psychology. Anxiety sensitivity (AS) is a dispositional trait where one is fearful of anxiety symptoms, and is distinguishable from the trait of anxiety itself. (Eke & McNally, 1996). These fears of anxiety-related sensations are an important factor in predicting the emergence and severity of panic symptoms (McNally, 2002). The Child Anxiety Sensitivity Index (CASI) is the child version of an 18-item self-report questionnaire commonly used to measure anxiety sensitivity. Zinbarg et al. (1997) demonstrated that the ASI has three first-order factors: Physical Concerns (i.e. “It scares me when my heart beats fast “), Mental Incapacitation Concerns (i.e. “When I am afraid, I worry that I might be crazy”), and Social Concerns (i.e. “Other kids can tell when I feel shaky “). The aim of the current study is to examine the relationship between scores on the CASI and responses during a low-dose carbon dioxide breathing task designed to induce panic-related sensations. The participants in our study were monozygotic and dizygotic twin pairs ranging from ages nine to thirteen. Twins’ responses throughout the task were measured using the Subjective Units of Distress Scale (SUDS) and the Diagnostic Symptom Questionnaire (DSQ), which measures cognitive and physical panic symptoms. We hypothesize that there is a positive relationship between the CASI and anxious responding during the carbon dioxide breathing task, such that as CASI scores increase, so do scores on the DSQ and SUDS. The results support the hypothesis and show significant evidence of a relationship between the CASI and subjectively experienced distress and panic symptoms. So, the more fearful an individual is of panic symptoms, the more severely they experience those symptoms, which in turn causes greater subjective distress. This study contributes to identifying the overall relationship between the CASI, DSQ, and SUDS scores when looking at physical, mental, and social concerns that contribute to the fear of experiencing subjective anxious symptoms.https://scholarscompass.vcu.edu/uresposters/1058/thumbnail.jp

Classifying the embedded young stellar population in Perseus and Taurus & the LOMASS database

Context. The classification of young stellar objects (YSOs) is typically done using the infrared spectral slope or bolometric temperature, but either can result in contamination of samples. More accurate methods to determine the evolutionary stage of YSOs will improve the reliability of statistics for the embedded YSO population and provide more robust stage lifetimes. Aims. We aim to separate the truly embedded YSOs from more evolved sources. Methods. Maps of HCO+ J=4-3 and C18O J=3-2 were observed with HARP on the James Clerk Maxwell Telescope (JCMT) for a sample of 56 candidate YSOs in Perseus and Taurus in order to characterize emission from high (column) density gas. These are supplemented with archival dust continuum maps observed with SCUBA on the JCMT and Herschel PACS to compare the morphology of the gas and dust in the protostellar envelopes. The spatial concentration of HCO+ J=4-3 and 850 micron dust emission are used to classify the embedded nature of YSOs. Results. Approximately 30% of Class 0+I sources in Perseus and Taurus are not Stage I, but are likely to be more evolved Stage II pre-main sequence (PMS) stars with disks. An additional 16% are confused sources with an uncertain evolutionary stage. Conclusions. Separating classifications by cloud reveals that a high percentage of the Class 0+I sources in the Perseus star forming region are truly embedded Stage I sources (71%), while the Taurus cloud hosts a majority of evolved PMS stars with disks (68%). The concentration factor method is useful to correct misidentified embedded YSOs, yielding higher accuracy for YSO population statistics and Stage timescales. Current estimates (0.54 Myr) may overpredict the Stage I lifetime on the order of 30%, resulting in timescales of 0.38 Myr for the embedded phase.Comment: 33 pages, 21 figures, 6 tables, Accepted to be published in A&