A VLA Survey For Faint Compact Radio Sources in the Orion Nebula Cluster

We present Karl G. Janksy Very Large Array (VLA) 1.3 cm, 3.6 cm, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster. We mosaicked 34 square arcminutes at 1.3 cm, 70 square arcminutes at 3.6 cm and 109 square arcminutes at 6 cm, containing 778 near-infrared detected YSOs and 190 HST-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source we fit a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from sub-millimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3 cm data, to search for and quantify variability of our sources.Comment: 13 pages, 6 figures, 4 tables, ApJ, in pres

Hierarchical Modeling Techniques to Analyze Contextual Effects: What Happened to the Aptitude by Treatment Design?

This article contrasts two analytical methods for making cross-level inferences between individual-level factors and group-level factors in school-effectiveness research, the aptitude by treatment interaction design and hierarchical linear modeling. Although the aptitude by treatment interaction method is suitable for making cross-level inferences when the intraclass correlations are low, partitioning the interaction into within-and between-contexts components is recommended to discern if the interaction is due to confounding contextual effects

The fact and the fiction: A prospective study of internet forum discussions on vaginal breech birth

© 2016 Australian College of Midwives Background Women with a breech baby late in pregnancy may use the internet to gather information to assist in decision-making for birth. The aim of this study was to examine how women use English language internet discussion forums to find out information about vaginal breech birth and to increase understanding of how vaginal breech birth is perceived among women. Method A descriptive qualitative study of internet discussion forums was undertaken. Google alerts were created with the search terms “breech birth” and “breech”. Alerts were collected for a one-year period (January 2013–December 2013). The content of forum discussions was analysed using thematic analysis. Results A total of 50 forum discussions containing 382 comments were collected. Themes that arose from the data were: Testing the waters—which way should I go?; Losing hope for the chance of a normal birth; Seeking support for options—who will listen to me?; Considering vaginal breech birth—a risky choice?; Staying on the ‘safe side’—caesarean section as a guarantee; Exploring the positive potential for vaginal breech birth. Conclusion Women search online for information about vaginal breech birth in an attempt to come to a place in their decision-making where they feel comfortable with their birth plan. This study highlights the need for clinicians to provide comprehensive, unbiased information on the risks and benefits of all options for breech birth to facilitate informed decision-making for the woman. This will contribute to improving the woman's confidence in distinguishing between “the fact and the fiction” of breech birth discussions online

Does Basic Skills Education Work? Some Evidence from the National Adult Literacy Survey

No Abstract available

Periodic Optical Variability of Radio Detected Ultracool Dwarfs

A fraction of very low mass stars and brown dwarfs are known to be radio active, in some cases producing periodic pulses. Extensive studies of two such objects have also revealed optical periodic variability and the nature of this variability remains unclear. Here we report on multi-epoch optical photometric monitoring of six radio detected dwarfs, spanning the $\sim$M8 - L3.5 spectral range, conducted to investigate the ubiquity of periodic optical variability in radio detected ultracool dwarfs. This survey is the most sensitive ground-based study carried out to date in search of periodic optical variability from late-type dwarfs, where we obtained 250 hours of monitoring, delivering photometric precision as low as $\sim$0.15%. Five of the six targets exhibit clear periodicity, in all cases likely associated with the rotation period of the dwarf, with a marginal detection found for the sixth. Our data points to a likely association between radio and optical periodic variability in late-M/early-L dwarfs, although the underlying physical cause of this correlation remains unclear. In one case, we have multiple epochs of monitoring of the archetype of pulsing radio dwarfs, the M9 TVLM 513-46546, spanning a period of 5 years, which is sufficiently stable in phase to allow us to establish a period of 1.95958 $\pm$ 0.00005 hours. This phase stability may be associated with a large-scale stable magnetic field, further strengthening the correlation between radio activity and periodic optical variability. Finally, we find a tentative spin-orbit alignment of one component of the very low mass binary LP 349-25.Comment: Accepted to The Astrophysical Journal; 22 pages; 12 figure

The role of planets in shaping planetary nebulae

In 1997 Soker laid out a framework for understanding the formation and shaping of planetary nebulae (PN). Starting from the assumption that non-spherical PN cannot be formed by single stars, he linked PN morphologies to the binary mechanisms that may have formed them, basing these connections almost entirely on observational arguments. In light of the last decade of discovery in the field of PN, we revise this framework, which, although simplistic, can still serve as a benchmark against which to test theories of PN origin and shaping. Within the framework, we revisit the role of planets in shaping PN. Soker invoked a planetary role in shaping PN because there are not enough close binaries to shape the large fraction of non-spherical PN. In this paper we adopt a model whereby only ~20% of all 1-8 solar mass stars make a PN. This reduces the need for planetary shaping. Through a propagation of percentages argument, and starting from the assumption that planets can only shape mildly elliptical PN, we conclude, like in Soker, that ~20% of all PN were shaped via planetary and other substellar interactions but we add that this corresponds to only ~5% of all 1-8 solar mass stars. This may be in line with findings of planets around main sequence stars. PN shaping by planets is made plausible by the recent discovery of planets that have survived interactions with red giant branch (RGB) stars. Finally, we conclude that of the ~80% of 1-8 solar mass stars that do not make a PN, about one quarter do not even ascend the AGB due to interactions with stellar and substellar companions, while three quarters ascend the AGB but do not make a PN. Once these stars leave the AGB they evolve normally and can be confused with post-RGB, extreme horizontal branch stars. We propose tests to identify them.Comment: 23 pages, accepted by PAS

Summary Judgment: Let the Movant Beware.

Abstract Forthcoming

How do social discourses of risk impact on women’s choices for vaginal breech birth? A qualitative study of women’s experiences

© 2016 Informa UK Limited, trading as Taylor & Francis Group. In this article, we aim to explore the impact of social discourses of risk around childbirth on the decisions made for birth by women who planned to have a breech baby late in pregnancy. This article uses data from a qualitative descriptive study in New South Wales, Australia in 2013. In the study, we talked to 22 women about their decision-making process for planned a vaginal breech birth and the impact of social discourses of risk on this decision. In total, 12 of these women had a vaginal birth and the other 10 had a Caesarean section. In this article, we note that the mothers talked about their option for birth in a social setting in which the dominant discourse focused on the riskiness of breech birth and the vulnerability of female bodies that required medical surveillance, supervision and intervention to ensure a safe birth. Thus, for these mothers their pregnancy was seen through the societal lens of risk and medicalisation, with surgical intervention through a Caesarean section seen by society as the optimum choice. Women could resist this dominant discourse but such resistance required both justification and action, for example, the women who wanted a vaginal birth often had to resist the pressure from their families to have a Caesarean section. We identified four related strands in women’s talk about resisting the dominate discourse: acknowledgment that they would be considered irrational for wanting a vaginal birth; having confidence in and believing that their body could give birth vaginally; convincing significant others that a vaginal birth was possible and desirable and looking for sources of support, for example, from new online social networks