On The Capacity of Surfaces in Manifolds with Nonnegative Scalar Curvature

Given a surface in an asymptotically flat 3-manifold with nonnegative scalar curvature, we derive an upper bound for the capacity of the surface in terms of the area of the surface and the Willmore functional of the surface. The capacity of a surface is defined to be the energy of the harmonic function which equals 0 on the surface and goes to 1 at infinity. Even in the special case of Euclidean space, this is a new estimate. More generally, equality holds precisely for a spherically symmetric sphere in a spatial Schwarzschild 3-manifold. As applications, we obtain inequalities relating the capacity of the surface to the Hawking mass of the surface and the total mass of the asymptotically flat manifold.Comment: 18 page

Reliability of Observational Assessment Methods for Outcome-based Assessment of Surgical Skill: Systematic Review and Meta-analyses

BACKGROUND: Reliable performance assessment is a necessary prerequisite for outcome-based assessment of surgical technical skill. Numerous observational instruments for technical skill assessment have been developed in recent years. However, methodological shortcomings of reported studies might negatively impinge on the interpretation of inter-rater reliability. OBJECTIVE: To synthesize the evidence about the inter-rater reliability of observational instruments for technical skill assessment for high-stakes decisions. DESIGN: A systematic review and meta-analysis were performed. We searched Scopus (including MEDLINE) and Pubmed, and key publications through December, 2016. This included original studies that evaluated reliability of instruments for the observational assessment of technical skills. Two reviewers independently extracted information on the primary outcome (the reliability statistic), secondary outcomes, and general information. We calculated pooled estimates using multilevel random effects meta-analyses where appropriate. RESULTS: A total of 247 documents met our inclusion criteria and provided 491 inter-rater reliability estimates. Inappropriate inter-rater reliability indices were reported for 40% of the checklists estimates, 50% of the rating scales estimates and 41% of the other types of assessment instruments estimates. Only 14 documents provided sufficient information to be included in the meta-analyses. The pooled Cohen's kappa was.78 (95% CI 0.69-0.89, p < 0.001) and pooled proportion agreement was 0.84 (95% CI 0.71-0.96, p < 0.001). A moderator analysis was performed to explore the influence of type of assessment instrument as a possible source of heterogeneity. CONCLUSIONS AND RELEVANCE: For high-stakes decisions, there was often insufficient information available on which to base conclusions. The use of suboptimal statistical methods and incomplete reporting of reliability estimates does not support the use of observational assessment instruments for technical skill for high-stakes decisions. Interpretations of inter-rater reliability should consider the reliability index and assessment instrument used. Reporting of inter-rater reliability needs to be improved by detailed descriptions of the assessment process

Evaluating sustainable intensification and diversification options for agriculture-based livelihoods within an aquatic biodiversity conservation context in Buxa, West Bengal, India

Potential impacts of sustainable intensification and diversification options for agriculture-based livelihoods in Buxa, West Bengal, India were evaluated using bioeconomic modelling. The baseline scenario involved multiple cropping seasons and a combination of crops on 0.9 ha landholdings, livestock husbandry, and exploitation of common property resources. With capital costs of Rs. 128,180 (US$2293) and annual operating costs of Rs. 37,290 (US$ 667), the net benefit generated (excluding depreciation) was Rs. 70,250 (US$1257) annually. The pay-back period was 1.8 years, and the Internal Rate of Return (IRR) was 53.7$ 1,342) and IRR to 56.5% with minimal added costs and risks. Adopting the system of rice intensification (SRI) for paddy cultivation on 0.35 ha increased the IRR to 61.1%, while reducing agrochemical and inorganic fertiliser use. Including small-scale fish culture in a 0.1 ha pond integrated in the irrigation scheme for SRI cultivation resulted in an IRR of 77.3% and reduced the pay-back period to 1.3 years. Some risks to biodiversity are apparent with each scenario; however, with appropriate safeguards, sustainable agricultural intensification and livelihoods diversification could bolster agrobiodiversity and social-ecological resilience of highland communities, while alleviating pressure on biodiversity

Aquatic and terrestrial invertebrate community responses to drying in chalk streams

Temporary streams are dynamic ecosystems that shift between wet and dry states and include the ‘winterbourne’ chalk streams of south England. Our understanding of temporary stream biodiversity is biased, with most research to date exploring aquatic invertebrate communities in benthic sediments during flowing phases. We surveyed the invertebrate communities of the Candover Brook chalk stream, comparing aquatic (benthic, hyporheic) and terrestrial communities in reaches with different flow permanence regimes. We used kick and Bou–Rouch sampling methods to collect aquatic invertebrates, and compared the terrestrial communities characterised by pitfall traps and ground searches and in different seasons. Although aquatic taxa richness was lower in temporary compared to perennial reaches, the total biodiversity of temporary stream channels was enhanced by contributions from both aquatic and terrestrial species, including several of conservation interest. We recommend that both aquatic and terrestrial communities should be considered in research and monitoring to characterise the biodiversity and ecological quality of temporary streams

Patterns of Suicidal Ideation and Behavior in Northern Ireland and Associations with Conflict Related Trauma

In this study, data from the World Mental Health Survey's Northern Ireland (NI) Study of Health and Stress (NISHS) was used to assess the associations between conflict- and non-conflict-related traumatic events and suicidal behaviour, controlling for age and gender and the effects of mental disorders in NI. DSM mental disorders and suicidal ideation, plans and attempts were assessed using the Composite International Diagnostic Interview (CIDI) in a multi-stage, clustered area probability household sample (N = 4,340, response rate 68.4%). The traumatic event categories were based on event types listed in the PTSD section of the CIDI. Suicidal ideation and attempts were more common in women than men, however, rates of suicide plans were similar for both genders. People with mood, anxiety and substance disorders were significantly more likely than those without to endorse suicidal ideation, plan or attempt. The highest odds ratios for all suicidal behaviors were for people with any mental disorder. However, the odds of seriously considering suicide were significantly higher for people with conflict and non-conflict-related traumatic events compared with people who had not experienced a traumatic event. The odds of having a suicide plan remain significantly higher for people with conflict-related traumatic events compared to those with only non-conflict-related events and no traumatic events. Finally, the odds of suicide attempt were significantly higher for people who have only non-conflict-related traumatic events compared with the other two categories. The results suggest that traumatic events associated with the NI conflict may be associated with suicidal ideation and plans, and this effect appears to be in addition to that explained by the presence of mental disorders. The reduced rates of suicide attempts among people who have had a conflict-related traumatic event may reflect a higher rate of single, fatal suicide attempts in this population

DOE Project 18545, AOP Task 2.0B, CRADA with Reaction Design

We ran 5 FACE fuels and 8 surrogate blends in diesel combustion with detailed particulate and exhaust chemistry measurements to provide data needed to develop and evaluate a kinetic model for particulate formation. Surrogate blends duplicated engine performance of real fuels. We demonstrated that a simple 2 surrogate blend is capable of duplicating the range of engine response for the FACE fuels, but that further tuning and complexity will be needed to reproduce emissions. We assisted in setting up a Jaguar computer user program for bench marking parallel solvers for chemistry in GPU machine environment. This program has just been approved by the Jaguar user facility and will begin in 2012

Uniqueness properties of the Kerr metric

We obtain a geometrical condition on vacuum, stationary, asymptotically flat spacetimes which is necessary and sufficient for the spacetime to be locally isometric to Kerr. Namely, we prove a theorem stating that an asymptotically flat, stationary, vacuum spacetime such that the so-called Killing form is an eigenvector of the self-dual Weyl tensor must be locally isometric to Kerr. Asymptotic flatness is a fundamental hypothesis of the theorem, as we demonstrate by writing down the family of metrics obtained when this requirement is dropped. This result indicates why the Kerr metric plays such an important role in general relativity. It may also be of interest in order to extend the uniqueness theorems of black holes to the non-connected and to the non-analytic case.Comment: 30 pages, LaTeX, submitted to Classical and Quantum Gravit

Uniqueness Theorem for Static Black Hole Solutions of sigma-models in Higher Dimensions

We prove the uniqueness theorem for self-gravitating non-linear sigma-models in higher dimensional spacetime. Applying the positive mass theorem we show that Schwarzschild-Tagherlini spacetime is the only maximally extended, static asymptotically flat solution with non-rotating regular event horizon with a constant mapping.Comment: 5 peges, Revtex, to be published in Class.Quantum Gra

A Mass Bound for Spherically Symmetric Black Hole Spacetimes

Requiring that the matter fields are subject to the dominant energy condition, we establish the lower bound $(4\pi)^{-1} \kappa {\cal A}$ for the total mass $M$ of a static, spherically symmetric black hole spacetime. (${\cal A}$ and $\kappa$ denote the area and the surface gravity of the horizon, respectively.) Together with the fact that the Komar integral provides a simple relation between $M - (4\pi)^{-1} \kappa A$ and the strong energy condition, this enables us to prove that the Schwarzschild metric represents the only static, spherically symmetric black hole solution of a selfgravitating matter model satisfying the dominant, but violating the strong energy condition for the timelike Killing field $K$ at every point, that is, $R(K,K) \leq 0$. Applying this result to scalar fields, we recover the fact that the only black hole configuration of the spherically symmetric Einstein-Higgs model with arbitrary non-negative potential is the Schwarzschild spacetime with constant Higgs field. In the presence of electromagnetic fields, we also derive a stronger bound for the total mass, involving the electromagnetic potentials and charges. Again, this estimate provides a simple tool to prove a ``no-hair'' theorem for matter fields violating the strong energy condition.Comment: 16 pages, LATEX, no figure