Magnetic fields and radiative feedback in the star formation process

Star formation is a complex process involving the interplay of many physical effects, including gravity, turbulent gas dynamics, magnetic fields and radiation. Our understanding of the process has improved substantially in recent years, primarily as a result of our increased ability to incorporate the relevant physics in numerical calculations of the star formation process. In this contribution we present an overview of our recent studies of star cluster formation in turbulent, magnetised clouds using self-gravitating radiation-magnetohydrodynamics calculations (Price and Bate 2008, 2009). Our incorporation of magnetic fields and radiative transfer into the Smoothed Particle Hydrodynamics method are discussed. We highlight how magnetic fields and radiative heating of the gas around newborn stars can solve several of the key puzzles in star formation, including an explanation for why star formation is such a slow and inefficient process. However, the presence of magnetic fields at observed strengths in collapsing protostellar cores also leads to problems on smaller scales, including a difficulty in forming protostellar discs and binary stars (Price and Bate 2007, Hennebelle and Teyssier 2008), which suggests that our understanding of the role of magnetic fields in star formation is not yet complete.Comment: 14 pages aip conf. format, 5 figures, submitted to AIP conf proc. of "Plasmas in the Laboratory and in the Universe: Interactions, Patterns and Turbulence", Como, Italy 1st-4th Dec 2009, eds. Bertin et al. Relevant movies at http://users.monash.edu.au/~dprice/mclusterRT/index.html#movie

The prompt hypothesis: clarification requests as corrective input for grammatical errors

The potential of clarification questions (CQs) to act as a form of corrective input for young children's grammatical errors was examined. Corrective responses were operationalized as those occasions when child speech shifted from erroneous to correct (E -> C) contingent on a clarification question. It was predicted that E -> C sequences would prevail over shifts in the opposite direction (C -> E), as can occur in the case of nonerror-contingent CQs. This prediction was tested via a standard intervention paradigm, whereby every 60s a sequence of two clarification requests (either specific or general) was introduced into conversation with a total of 45 2- and 4-year-old children. For 10 categories of grammatical structure, E -> C sequences predominated over their C -> E counterparts, with levels of E -> C shifts increasing after two clarification questions. Children were also more reluctant to repeat erroneous forms than their correct counterparts, following the intervention of CQs. The findings provide support for Saxton's prompt hypothesis, which predicts that error-contingent CQs bear the potential to cue recall of previously acquired grammatical forms

The Relation of Presence and Virtual Reality Exposure for Treatment of Flying Phobia

A growing body of literature suggests that Virtual Reality is a successful tool for exposure therapy for anxiety disorders. Virtual Reality (VR) researchers posit the construct of presence, interpreting an artificial stimulus as if it were real, as the mechanism that enables anxiety to be felt during virtual reality exposure therapy (VRE). However, empirical studies on the relation between presence and anxiety in VRE have yielded mixed findings. The current study tested the following hypotheses 1) Presence is related to in session anxiety and treatment outcome; 2) Presence mediates the extent that pre-existing (pre-treatment) anxiety is experienced during exposure with VR; 3) Presence is positively related to the amount of phobic elements included within the virtual environment. Results supported presence as the mechanism by which anxiety is experienced in the virtual environment as well as a relation between presence and the phobic elements, but did not support a relation between presence and treatment outcom

The Effect of Post Event Processing on Response to Exposure Therapy among those with Social Anxiety Disorder

Exposure therapy has received a great deal of support as an effective treatment for social anxiety. However, not all those who undergo exposure therapy improve, and some of those who do respond continue to report significant levels of symptoms. A theorized mechanism of change for exposure therapy is extinction learning. Extinction learning is believed to occur across exposure sessions during which new associations are formed and stored in memory. Individuals with social anxiety are prone to engage in post event processing (PEP), or rumination, after social experiences, which may interfere with extinction learning, and thus attenuate response to treatment. The current study examined whether PEP limits treatment response to two different exposure based treatments, a group based cognitive behavioral intervention and an individually based virtual reality exposure therapy among participants (n = 75) diagnosed with social anxiety disorder. The findings suggested that PEP decreased as a result of treatment and that social anxiety symptoms for those with greater amounts of PEP improved at a slower rate of change than those with lower levels of PEP. Implications for the role of PEP on treatment response are discussed

Improving Nurse Support of Patient Satisfaction Surveys through Team Huddle Education

Problem As a leading cause of death and disability in the US, strokes often require complex, multifaceted care. Often ignored, patient satisfaction is a crucial aspect of this care and is positively linked to key health indicators. Regulatory guidelines underscore the need for stroke-specific patient satisfaction survey (SSPS) utilization in post-stroke care. Context Hospital X is a large Comprehensive Stroke Center in the Bay Area, serving patients with various stroke etiologies and complexities. At present, its Neuro Observational Unit (NOU) does not administer a SSPS. Intervention To address this gap in care, an educational presentation using literature evidence in support of SSPS was presented to nursing staff during the monthly department meeting. Measures The aim of this presentation was to ensure 100% of nurses in the NOU acknowledge SSPS importance by April 18, 2024 to maintain safe, quality care for stroke patients and meet regulatory standards. Successful change in practice was evaluated through a questionnaire administered before and after the education module. It gauged nursing staff attitudes toward SSPS and their likelihood of encouraging patient participation on a Likert scale from 1 to 5. Results The QI team found average pre-intervention scores of 4.4 and 3.6 for significance and likeliness to encourage, respectively, and post-intervention Likert scores of 4.1 and 3.6, respectively. Optional comments from nurses implied confusion about their role in SSPS implementation. Conclusions These results suggest that Hospital X NOU nursing staff are open to implementing a SSPS, but require clarification on their role

Smoothed particle magnetohydrodynamic simulations of protostellar outflows with misaligned magnetic field and rotation axes

We have developed a modified form of the equations of smoothed particle magnetohydrodynamics which are stable in the presence of very steep density gradients. Using this formalism, we have performed simulations of the collapse of magnetised molecular cloud cores to form protostars and drive outflows. Our stable formalism allows for smaller sink particles (< 5 AU) than used previously and the investigation of the effect of varying the angle, {\theta}, between the initial field axis and the rotation axis. The nature of the outflows depends strongly on this angle: jet-like outflows are not produced at all when {\theta} > 30{\deg}, and a collimated outflow is not sustained when {\theta} > 10{\deg}. No substantial outflows of any kind are produced when {\theta} > 60{\deg}. This may place constraints on the geometry of the magnetic field in molecular clouds where bipolar outflows are seen.Comment: Accepted for publication in MNRAS, 13 pages, 14 figures. Animations can be found at http://www.astro.ex.ac.uk/people/blewis/research/outflows_misaligned_fields.htm

Constrained hyperbolic divergence cleaning in smoothed particle magnetohydrodynamics with variable cleaning speeds

We present an updated constrained hyperbolic/parabolic divergence cleaning algorithm for smoothed particle magnetohydrodynamics (SPMHD) that remains conservative with wave cleaning speeds which vary in space and time. This is accomplished by evolving the quantity $\psi / c_h$ instead of $\psi$. Doing so allows each particle to carry an individual wave cleaning speed, $c_h$, that can evolve in time without needing an explicit prescription for how it should evolve, preventing circumstances which we demonstrate could lead to runaway energy growth related to variable wave cleaning speeds. This modification requires only a minor adjustment to the cleaning equations and is trivial to adopt in existing codes. Finally, we demonstrate that our constrained hyperbolic/parabolic divergence cleaning algorithm, run for a large number of iterations, can reduce the divergence of the field to an arbitrarily small value, achieving $\nabla \cdot B=0$ to machine precision.Comment: 23 pages, 16 figures, accepted for publication in Journal of Computational Physic

LISTENING TO THE COMMUNITY: AN APPRECIATIVE CASE STUDY OF SERVICE-LEARNING INITIATIVES WITHIN A HIGHER EDUCATION INSTITUTION

Service-learning has become a prevalent topic of discussion on college and university campuses across the United States. Students engage in internships, service activities, and mission trips to far-away places as well as neighborhoods down the street in order to gain experience and apply what they are learning in a realistic setting. The purpose of this study was to identify ways a higher education institution listens to the voice of the community in which it resides throughout its implementation of service-learning initiatives. The concept of power, as described by Lukes (2005), provided the primary theoretical framework for this case study informed by Appreciative Inquiry. Data were collected through interviews with community partners who had collaborated with the university in service-learning activities, as well as university students, faculty, and members of the senior leadership team. Additional data were collected through observations and review of institutional artifacts. The findings of this study indicated that service is an integral part of the curricular and co-curricular offerings of the institution examined. Using the major classifications of discover, dream, design, and destiny found in Appreciative Inquiry, the overarching themes which emerged from the study included issues of building trust, ameliorating misunderstandings, fulfilling both community and institutional missions, and recognizing that service is a part of a democratic society. Examining community voice in service-learning relationships is important because power and influence exerted by members of the academy could thwart the citizens they purport to serve. The findings of this study illustrated examples of positive town-gown relationships whereby institutional constituents and community partners created collaborative experiential learning which fostered benefits on multiple levels. Issues such as sustainability, applying research to practice, honoring individual and collective strengths, and adaptability to democratic social change were described as tenets of effective service-learning as well as suggested as the ideals adult educators should seek to incorporate into their daily practice