Spacetime and orbits of bumpy black holes

Our universe contains a great number of extremely compact and massive objects which are generally accepted to be black holes. Precise observations of orbital motion near candidate black holes have the potential to determine if they have the spacetime structure that general relativity demands. As a means of formulating measurements to test the black hole nature of these objects, Collins and Hughes introduced "bumpy black holes": objects that are almost, but not quite, general relativity's black holes. The spacetimes of these objects have multipoles that deviate slightly from the black hole solution, reducing to black holes when the deviation is zero. In this paper, we extend this work in two ways. First, we show how to introduce bumps which are smoother and lead to better behaved orbits than those in the original presentation. Second, we show how to make bumpy Kerr black holes -- objects which reduce to the Kerr solution when the deviation goes to zero. This greatly extends the astrophysical applicability of bumpy black holes. Using Hamilton-Jacobi techniques, we show how a spacetime's bumps are imprinted on orbital frequencies, and thus can be determined by measurements which coherently track a small orbiting body's orbital phase. We find that weak-field orbits of bumpy black holes are modified exactly as expected from a Newtonian analysis of a body with a prescribed multipolar structure, reproducing well-known results from the celestial mechanics literature. The impact of bumps on strong-field orbits is especially strong, suggesting that this framework will allow observations to set robust limits on the extent to which a spacetime's multipoles deviate from the black hole expectation.Comment: 24 pages, 3 figures, accepted to Phys. Rev. D. This version corrects some typos and incorporates suggested edit

Facilitating goal-oriented behaviour in the Stroop task: when executive control is influenced by automatic processing.

A portion of Stroop interference is thought to arise from a failure to maintain goal-oriented behaviour (or goal neglect). The aim of the present study was to investigate whether goal- relevant primes could enhance goal maintenance and reduce the Stroop interference effect. Here it is shown that primes related to the goal of responding quickly in the Stroop task (e.g. fast, quick, hurry) substantially reduced Stroop interference by reducing reaction times to incongruent trials but increasing reaction times to congruent and neutral trials. No effects of the primes were observed on errors. The effects on incongruent, congruent and neutral trials are explained in terms of the influence of the primes on goal maintenance. The results show that goal priming can facilitate goal-oriented behaviour and indicate that automatic processing can modulate executive control

Influence of built environment and social capital on mental health of residents of assisted living communities in Louisville, KY.

Objectives: Prior research has shown social capital and built environment quality are associated with overall health status and the incidence of mental illness. This study explores the relationship between social capital, built environment, and quality of life specifically for assisted living residents, currently a gap in the literature. Method: A total of 76 assisted living residents were interviewed for the study using researcher-administered questionnaires. In addition, site audits were conducted to quantitatively evaluate the built environment surrounding 12 assisted living communities in the Louisville Metro region. Results: There was a moderate, positive correlation between social capital and mental health, r = .473, p \u3c .001. Built environment quality for the neighborhood immediately surrounding the assisted living community was not significantly correlated with quality of life for assisted living residents. Other population characteristics, including demographic characteristics, self-rated health status, and instrumental activities of daily living were not significantly predictive of mental health scores. Conclusion: This study demonstrates that social capital is associated with happiness and self-rated quality of life. Specifically, increased social capital is associated with increased mental well-being for older adults residing in assisted living communities, with social capital explaining about 20% of the variation in quality of life scores

Adolescent mental health: Challenges with maternal noncompliance

The leading cause of suicide ideation, attempts, and completion in adolescents is persistent and unresolved parental conflict. National statistics show extremely high rates of childhood neglect and abuse are perpetrated most often by single mothers. Psychiatric disorders arising from maternal–child dysfunction are well-documented. However, resources to prevent offspring victimization are lacking. Here, we report maternal neglect of a 15-year-old male brought to the psychiatric emergency room for suicidal ideation. An inpatient treatment plan including pharmacotherapy, family therapy and psychological testing was initiated. The patient’s mother failed to attend clinic appointments or family therapy sessions. Clinician attempts to engage the mother in the treatment plan was met with verbal assaults, aggression, and threatening behavior. The patient decompensated in relation to the mother’s actions. Child Protective Services were contacted and a follow-up assessment with the patient and mother is pending. Psychiatric treatment of the mother may be a necessary intervention and prevention regimen for both the adolescent and the mother. Without consistent Child Protective Services oversight, medical and psychosocial follow-up, the prognosis and quality of life for this adolescent is considered very poor. Stringent mental health law and institutional policies are needed to adequately intercede and protect adolescents with mental illness

Gyroscopes orbiting black holes: A frequency-domain approach to precession and spin-curvature coupling for spinning bodies on generic Kerr orbits

A small body orbiting a black hole follows a trajectory that, at leading order, is a geodesic of the black hole spacetime. Much effort has gone into computing "self-force" corrections to this motion, arising from the small body's own contributions to the system's spacetime. Another correction to the motion arises from coupling of the small body's spin to the black hole's spacetime curvature. Spin-curvature coupling drives a precession of the small body, and introduces a "force" (relative to the geodesic) which shifts the small body's worldline. These effects scale with the small body's spin at leading order. In this paper, we show that the equations which govern spin-curvature coupling can be analyzed with a frequency-domain decomposition, at least to leading order in the small body's spin. We show how to compute the frequency of precession along generic orbits, and how to describe the small body's precession and motion in the frequency domain. We illustrate this approach with a number of examples. This approach is likely to be useful for understanding spin coupling effects in the extreme mass ratio limit, and may provide insight into modeling spin effects in the strong field for nonextreme mass ratios.National Science Foundation (U.S.) (Grant PHY-1403261

Review of Residential Low-Load HVAC Systems

In support of the U.S. Department of Energy’s (DOE’s) Building America Program, Pacific Northwest National Laboratory (PNNL) conducted an investigation to inventory commercially available HVAC technologies that are being installed in low-load homes. The first step in this investigation was to conduct a review of published literature to identify low-load HVAC technologies available in the United States and abroad, and document the findings of existing case studies that have evaluated the performance of the identified technologies. This report presents the findings of the literature review, identifies gaps in the literature or technical understanding that must be addressed before low-load HVAC technologies can be fully evaluated, and introduces PNNL’s planned research and analysis for this project to address identified gaps and potential future work on residential low-load HVAC systems

Clostridium difficile infection in the United States: A national study assessing preventive practices used and perceptions of practice evidence

We surveyed 571 US hospitals about practices used to prevent Clostridium difficile infection (CDI). Most hospitals reported regularly using key CDI prevention practices, and perceived their strength of evidence as high. The largest discrepancy between regular use and perceived evidence strength occurred with antimicrobial stewardship programs.Infect. Control Hosp. Epidemiol. 2015;36(8):969–971</jats:p

Positive emotion enhances association-memory

The influence of emotion on association-memory is often attributed to arousal, but negative stimuli are typically used to test for these effects. While prior studies of negative emotion on association-memory have found impairments, theories suggest that positive emotion may have a distinct effect on memory, and may lead to enhanced association-memory. Here we tested participants’ memory for pairs of positive and neutral words using cued recall, supplemented with a mathematical modeling approach designed to disentangle item- versus association-memory effects that may otherwise confound cued-recall performance. We consistently found enhanced association-memory due to positive emotion. These results provide further evidence that positive information is processed differently than negative and that, when examining association formation, valence as well as arousal must be considered