Spitzer observations of Bow Shocks and Outflows in RCW 38

We report Spitzer observations of five newly identified bow shocks in the massive star-forming region RCW 38. Four are visible at IRAC wavelengths, the fifth is visible only at 24 microns. Chandra X-ray emission indicates that winds from the central O5.5 binary, IRS~2, have caused an outflow to the NE and SW of the central subcluster. The southern lobe of hot ionised gas is detected in X-rays; shocked gas and heated dust from the shock-front are detected with Spitzer at 4.5 and 24 microns. The northern outflow may have initiated the present generation of star formation, based on the filamentary distribution of the protostars in the central subcluster. Further, the bow-shock driving star, YSO 129, is photo-evaporating a pillar of gas and dust. No point sources are identified within this pillar at near- to mid-IR wavelengths. We also report on IRAC 3.6 & 5.8 micron observations of the cluster DBS2003-124, NE of RCW 38, where 33 candidate YSOs are identified. One star associated with the cluster drives a parsec-scale jet. Two candidate HH objects associated with the jet are visible at IRAC and MIPS wavelengths. The jet extends over a distance of ~3 pc. Assuming a velocity of 100 km/s for the jet material gives an age of about 30,000 years, indicating that the star (and cluster) are likely to be very young, with a similar or possibly younger age than RCW 38, and that star formation is ongoing in the extended RCW 38 region.Comment: 27 pages, 6 figures, accepted to Ap

Detection of magnetic field in the B2 star ρ\rho Oph A with ESO FORS2

Circumstantial evidence suggests that magnetism and enhanced X-ray emission are likely correlated in early B-type stars: similar fractions of them ($\sim$ 10 %) are strong and hard X-ray sources and possess strong magnetic fields. It is also known that some B-type stars have spots on their surface. Yet up to now no X-ray activity associated with spots on early-type stars was detected. In this Letter we report the detection of a magnetic field on the B2V star $\rho$ Oph A. Previously, we assessed that the X-ray activity of this star is associated with a surface spot, herewith we establish its magnetic origin. We analyzed FORS2 ESO VLT spectra of $\rho$ Oph A taken at two epochs and detected a longitudinal component of the magnetic field of order of $\sim500$ G in one of the datasets. The detection of the magnetic field only at one epoch can be explained by stellar rotation which is also invoked to explain observed periodic X-ray activity. From archival HARPS ESO VLT high resolution spectra we derived the fundamental stellar parameters of $\rho$ Oph A and further constrained its age. We conclude that $\rho$ Oph A provides strong evidence for the presence of active X-ray emitting regions on young magnetized early type stars.Comment: 4 pages, 1 figure, 2 tables, accepted as a "Letter to the Editor" to Astronomy & Astrophysic

Book Review - Social Security after Fifty: Successes and Failures by Edward D. Berkowitz

In many ways, this compact little book is a celebration. It is a celebration of the cornerstone of the American social welfare system, the Social Security Act of 1935. It is a celebration of the flexibility of an American political economic system that adjusts, somewhat reluctantly, to the vagaries of a capitalist system. Mainly, it is a celebration of the personality and work of three people instrumental in the development, implementation, and maintenance of an American institution; Wilbur Cohen, Robert Myers, and Robert Ball

In the Case of Manipulation

This article reports on the findings of research into the manipulative tendencies of 289 professional social workers in Michigan. Utilizing the Machiavellian scale and comparing the results with other studies, the author concludes that social workers, contrary to the conventional wisdom, have strong manipulative tendencies. Additionally, the more manipulative social workers are not isolated in any specific field or area of practice, but are scattered throughout the profession. Rather than be alarmed by this recognition, the author feels the profession must accept this reality and acknowledge that these manipulative tendencies are mitigated by a compassionate, humanistic value system

The Structure of the Star-forming Cluster RCW 38

We present a study of the structure of the high mass star-forming region RCW~38 and the spatial distribution of its young stellar population. Spitzer IRAC photometry 3-8um are combined with 2MASS near-IR data to identify young stellar objects by IR-excess emission from their circumstellar material. Chandra X-ray data are used to identify class III pre-main sequence stars lacking circumstellar material. We identify 624 YSOs: 23 class 0/I and 90 flat spectrum protostars, 437 Class II stars, and 74 Class III stars. We also identify 29 (27 new) O star candidates over the IRAC field. Seventy-two stars exhibit IR-variability, including seven class 0/I and 12 flat spectrum YSOs. A further 177 tentative candidates are identified by their location in the IRAC [3.6] vs. [3.6]-[5.8] cmd. We find strong evidence of subclustering in the region. Three subclusters were identified surrounding the central cluster, with massive and variable stars in each subcluster. The central region shows evidence of distinct spatial distributions of the protostars and pre-main sequence stars. A previously detected IR cluster, DB2001_Obj36, has been established as a subcluster of RCW 38. This suggests that star formation in RCW 38 occurs over a more extended area than previously thought. The gas to dust ratio is examined using the X-ray derived hydrogen column density, N_H and the K-band extinction, and found to be consistent with the diffuse ISM, in contrast with Serpens & NGC1333. We posit that the high photoionising flux of massive stars in RCW 38 affects the agglomeration of the dust grains.Comment: 98 pages, 15 figure

Fast Quasi-Threshold Editing

We introduce Quasi-Threshold Mover (QTM), an algorithm to solve the quasi-threshold (also called trivially perfect) graph editing problem with edge insertion and deletion. Given a graph it computes a quasi-threshold graph which is close in terms of edit count. This edit problem is NP-hard. We present an extensive experimental study, in which we show that QTM is the first algorithm that is able to scale to large real-world graphs in practice. As a side result we further present a simple linear-time algorithm for the quasi-threshold recognition problem.Comment: 26 pages, 4 figures, submitted to ESA 201

The construction of a social studies vocabulary test for teachers in training.

Thesis (Ed.M.)--Boston Universit

Differential Perception And Adolescent Drinking In The United States: Preliminary Considerations

This paper addresses adolescent drinking from a perspective very similar to Sutherland\u27s differential association theory. Drinking occurs when positive perceptions of drinking outweigh or outnumber negative ones. Our research focuses on images of drinking communicated by rationalized sources organized specifically to shape perceptions of drinking. We call these organizations agencies and assess their impact on perceptions of drinking. It is our contention that the political economic context of the United States in which these agencies function is such that positive images of drinking outnumber and outweigh negative ones, and that this is an important factor contributing to adolescent drinking

Alcohol Intake and Mortality among Women with Invasive Breast Cancer

Background: Alcohol intake has consistently been associated with increased breast cancer incidence in epidemiological studies. However, the relation between alcohol and survival after breast cancer diagnosis is less clear. Methods: We investigated whether alcohol intake was associated with survival among 3146 women diagnosed with invasive breast cancer in the Swedish Mammography Cohort. Alcohol consumption was estimated using a food frequency questionnaire. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs). Results: From 1987 to 2008 there were 385 breast cancer-specific deaths and 860 total deaths. No significant association was observed between alcohol intake and breast cancer-specific survival. Women who consumed 10 g per day (corresponding to approximately 0.75 to 1 drinks) or more of alcohol had an adjusted HR (95% CI) of breast cancer-specific death of 1.36 (0.82–2.26;p$_{trend}$=0.47) compared with non-drinkers. A significant inverse association was observed between alcohol and non-breast cancer deaths. Those who consumed 3.4–9.9 g per day of alcohol had a 33% lower risk of death compared with non-drinkers (95% CI 0.50–0.90;p$_{trend}$=0.04). Conclusion: Our findings suggest that alcohol intake up to approximately one small drink per day does not negatively impact breast cancer-specific survival and a half drink per day is associated with a decreased risk of mortality from other causes