Testing Gravity in the Outer Solar System: Results from Trans-Neptunian Objects

The inverse square law of gravity is poorly probed by experimental tests at distances of ~ 10 AUs. Recent analysis of the trajectory of the Pioneer 10 and 11 spacecraft have shown an unmodeled acceleration directed toward the Sun which was not explained by any obvious spacecraft systematics, and occurred when at distances greater than 20 AUs from the Sun. If this acceleration represents a departure from Newtonian gravity or is indicative of an additional mass distribution in the outer solar system, it should be detectable in the orbits of Trans-Neptunian Objects (TNOs). To place limits on deviations from Newtonian gravity, we have selected a well observed sample of TNOs found orbiting between 20 and 100 AU from the Sun. By examining their orbits with modified orbital fitting software, we place tight limits on the perturbations of gravity that could exist in this region of the solar system.Comment: 20 pages, 4 figures, 2 tables, uses AASTex v5.x macro

Subtypes of Attentional Bias within Social Anxiety Disorder: Evaluating Changes following Cognitive Behavioral Therapy

Prominent theories of social anxiety disorder (SAD) describe the role of attentional bias in the disorder\u27s etiology and maintenance; some models implicate bias toward social threats (e.g., Rapee & Heimberg, 1997) and others implicate bias to avoid them (e.g., Clark & Wells, 1995). The present investigation examined: 1) whether a clinical sample of individuals with SAD comprises two distinct groups based on attention bias for social threat (vigilant, avoidant), and 2) group-specific changes in attention bias following cognitive behavioral therapy (CBT) for SAD. Consistent with predictions, results yielded evidence of two pre-treatment groups (vigilant and avoidant). After eight weeks of treatment, the direction of change in attention bias differed between groups, such that the vigilant group became less vigilant, and the avoidant group became less avoidant, with the avoidant group showing a significant change in attention bias from pre- to post-treatment. These findings provide preliminary support for the hypothesis that SAD comprises subgroups with both threat vigilant and threat avoidant attentional styles and change in different directions following treatment. Implications for how individuals who exhibit one attentional bias or the other may differentially respond to treatment are discussed

Does engagement with exposure yield better outcomes?: Components of presence as a predictor of treatment response for virtual reality exposure therapy for social phobia

Virtual reality exposure (VRE) has been shown to be effective for treating a variety of anxiety disorders, including social phobia. Presence, or the level of connection an individual feels with the virtual environment, is widely discussed as a critical construct both for the experience of anxiety within a virtual environment and for a successful response to VRE. Two published studies show that whereas generalized presence relates to fear ratings during VRE, it does not relate to treatment response. However, presence has been conceptualized as multidimensional, with three primary factors (spatial presence, involvement, and realness). These factors can be linked to other research on the facilitation of fear during exposure, inhibitors of treatment response (e.g., distraction), and more recent theoretical discussions of the mechanisms of exposure therapy, such as Bouton’s (2004) description of expectancy violation. As such, one or more of these components of presence may be more strongly associated with the experience of fear during VRE and treatment response than the overarching construct. The current study (N=41) evaluated relations between three theorized components of presence, fear ratings during VRE, and treatment response for VRE for social phobia. Results suggest that total presence and realness subscale scores were related to in-session peak fear ratings. However, only scores on the involvement subscale significantly predicted treatment response. Implications of these findings are discussed

Analytic approximation and an improved method for computing the stress-energy of quantized scalar fields in Robertson-Walker spacetimes

An improved method is given for the computation of the stress-energy tensor of a quantized scalar field using adiabatic regularization. The method works for fields with arbitrary mass and curvature coupling in Robertson-Walker spacetimes and is particularly useful for spacetimes with compact spatial sections. For massless fields it yields an analytic approximation for the stress-energy tensor that is similar in nature to those obtained previously for massless fields in static spacetimes.Comment: RevTeX, 8 pages, no figure

Semiclassical charged black holes with a quantized massive scalar field

Semiclassical perturbations to the Reissner-Nordstrom metric caused by the presence of a quantized massive scalar field with arbitrary curvature coupling are found to first order in \epsilon = \hbar/M^2. The DeWitt-Schwinger approximation is used to determine the vacuum stress-energy tensor of the massive scalar field. When the semiclassical perturbation are taken into account, we find extreme black holes will have a charge-to-mass ratio that exceeds unity, as measured at infinity. The effects of the perturbations on the black hole temperature (surface gravity) are studied in detail, with particular emphasis on near extreme ``bare'' states that might become precisely zero temperature ``dressed'' semiclassical black hole states. We find that for minimally or conformally coupled scalar fields there are no zero temperature solutions among the perturbed black holes.Comment: 19 pages; 1 figure; ReVTe

Child Maltreatment and Disaster Prevention: Qualitative Study of Community Agency Perspectives

Introduction: Child maltreatment (CM) is a significant public health problem that increases following natural disasters. Ecological approaches have been used to study these complex phenomena, and the current research fits within this perspective by conducting qualitative interviews with disaster response and family-serving community agencies. The purpose of the study was to identify whether or not community agencies identified CM as an issue that is relevant for disaster planning and response and their perspectives on risk and protective factors for CM risk following disaster. Methods: Agencies (n=16) from 2 geographical areas participated - one that recently experienced a natural disaster (Louisiana (LA), n=7) and one that had not (Georgia (GA), n=9). Agency representatives completed semi-structured telephone interviews (n=16) and follow up in person focus groups (n=14). Theory-driven, thematic analyses were completed. Results: Results suggested that community agencies agree that post-disaster environments increase the risk for CM and that CM prevention has a role in disaster response planning. Risk and protective factors were identified according to Bronfenbrenner’ s ecological framework. Conclusion: Study results support the need to include CM prevention efforts within disaster planning and provide guidance for future research to inform such efforts. [West J Emerg Med. 2013;14(4):402–408

The Role of Psychological Flexibility in Mental Health Stigma and Psychological Distress for the Stigmatizer

Although the negative consequences of stigmatization on those with psychological disorders have been well-documented, little is known about the impact of stigmatization on individuals who report having such stigmatizing attitudes. The present set of studies first investigated whether there was a link between stigmatizing attitudes toward people with psychological disorders and one’s own level of psychological distress. In addition, psychological flexibility was explored as a possible facet of this relation. As predicted, results revealed that there was a significant positive correlation between mental health stigma and psychological distress. Furthermore, the results suggested that psychological flexibility may be a shared feature of mental health stigma and psychological distress. Exploring the role of psychological flexibility appears to be a promising construct for conceptualizing and treating mental health stigma

The Role of Psychological Flexibility in Mental Health Stigma and Psychological Distress for the Stigmatizer

Although the negative consequences of stigmatization on those with psychological disorders have been well-documented, little is known about the impact of stigmatization on individuals who report having such stigmatizing attitudes. The present set of studies first investigated whether there was a link between stigmatizing attitudes toward people with psychological disorders and one’s own level of psychological distress. In addition, psychological flexibility was explored as a possible facet of this relation. As predicted, results revealed that there was a significant positive correlation between mental health stigma and psychological distress. Furthermore, the results suggested that psychological flexibility may be a shared feature of mental health stigma and psychological distress. Exploring the role of psychological flexibility appears to be a promising construct for conceptualizing and treating mental health stigma

Quantum Backreaction on ``Classical'' Variables

A mathematically consistent procedure for coupling quasiclassical and quantum variables through coupled Hamilton-Heisenberg equations of motion is derived from a variational principle. During evolution, the quasiclassical variables become entangled with the quantum variables with the result that the value of the quasiclassical variables depends on the quantum state. This provides a formalism to compute the backreaction of any quantum system on a quasiclassical one. In particular, it leads to a natural candidate for a theory of gravity coupled to quantized matter in which the gravitational field is not quantized.Comment: LaTeX, 10 pp. title change, minor improvement of presentatio

Can Minor Planets be Used to Assess Gravity in the Outer Solar System?

The twin Pioneer spacecraft have been tracked for over thirty years as they headed out of the solar system. After passing 20 AU from the Sun, both exhibited a systematic error in their trajectories that can be interpreted as a constant acceleration towards the Sun. This Pioneer Effect is most likely explained by spacecraft systematics, but there have been no convincing arguments that that is the case. The alternative is that the Pioneer Effect represents a real phenomenon and perhaps new physics. What is lacking is a means of measuring the effect, its variation, its potential anisotropies, and its region of influence. We show that minor planets provide an observational vehicle for investigating the gravitational field in the outer solar system, and that a sustained observation campaign against properly chosen minor planets could confirm or refute the existence of the Pioneer Effect. Additionally, even if the Pioneer Effect does not represent a new physical phenomenon, minor planets can be used to probe the gravitational field in the outer Solar System and since there are very few intermediate range tests of gravity at the multiple AU distance scale, this is a worthwhile endeavor in its own right.Comment: Accepted for publication in The Astrophysical Journa