On inferring standard deviations from path dependent options

Path dependent option prices are employed to derive implied standard deviations of the underlying security price process without recourse to numerical procedures. We empirically illustrate our methodology by inferring the volatility of gold prices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25893/1/0000456.pd

An empirical investigation of the EOE gold options market

On April 2, 1981, the European Option Exchange introduced the first organized exchange trading of options on spot gold. We study this new market for three months at its inception and in a parallel period a year later via various tests of rational boundary conditions. Additionally, we use call-put parity to infer implied risk free rates (IRFR's). Deviations of the IRFR's from the prevailing risk free rate permit the possibility of arbitrage through positions known as forward and reverse conversions. Our tests are modified to allow for transaction costs to more fully address the question of market efficiency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25742/1/0000302.pd

Capturing Debriefing and Enhancing Reflection within Simulated Clinical Learning Environments

This article presents findings from an evaluation of a new A3-size learner notes sheet designed for use by healthcare students engaging in clinical simulation and clinical skills sessions. The notes sheet consists of an adapted form of the SBAR (situation, background, assessment, response) tool, whilst capturing post-simulation oral debriefing provided by a facilitator. Additionally, the Driscoll (2007)model is used to provide students with an opportunity to reflect on their engagement in clinical simulation. Two cohorts of students, who engaged in separate simulation sessions, completed the A3 sheet. The study featured 33 midwifery and 21 operating department practitioner (ODP) students undertaking a simulation. Documentary analysis was undertaken to identify the depth of reflective writing of both groups of students. Midwifery student participants reflected on their experiences of simulation at a slightly deeper level than their ODP counterparts. All students adhered to the structure of the notes sheet when receiving their briefing from the facilitator and when asked to write their reflective accounts. This study has sought to explore an under-researched area of clinical simulation: the extent to which healthcare students can utilise reflection when engaging with a clinical scenario within a simulated learning environment

Airborne electromagnetic imaging of discontinuous permafrost

The evolution of permafrost in cold regions is inextricably connected to hydrogeologic processes, climate, and ecosystems. Permafrost thawing has been linked to changes in wetland and lake areas, alteration of the groundwater contribution to stream flow, carbon release, and increased fire frequency. But detailed knowledge about the dynamic state of permafrost in relation to surface and groundwater systems remains an enigma. Here, we present the results of a pioneering ~1,800 line-kilometer airborne electromagnetic survey that shows sediments deposited over the past ~4 million years and the configuration of permafrost to depths of ~100 meters in the Yukon Flats area near Fort Yukon, Alaska. The Yukon Flats is near the boundary between continuous permafrost to the north and discontinuous permafrost to the south, making it an important location for examining permafrost dynamics. Our results not only provide a detailed snapshot of the present-day configuration of permafrost, but they also expose previously unseen details about potential surface – groundwater connections and the thermal legacy of surface water features that has been recorded in the permafrost over the past 1,000 years. This work will be a critical baseline for future permafrost studies aimed at exploring the connections between hydrogeologic, climatic, and ecological processes, and has significant implications for the stewardship of Arctic environments

Protocol: Personality assessment as a support for referral and case-work in treatment for substance use disorders (PASRC-study)

<p>Abstract</p> <p>Background</p> <p>Assessment of co-morbid personality disorders in substance use disorders may lead to important insights concerning individual patients. However, little is known about the potential value of routine personality disorder assessment in a clinical context.</p> <p>Methods</p> <p>Patients are adults with past-year substance dependence seeking treatment at a centralized intake unit for substance abusers in the City of Copenhagen. A randomized controlled trial of assessment of personality disorders and individual feedback vs. a general life situation interview. Patients are followed at 3 and 6 months post-treatment</p> <p>Discussion</p> <p>If routine personality assessment improves outcomes of substance abuse treatment, the clinical implication is to increase the use of personality disorder assessment in substance abuse treatment settings.</p> <p>Trial registration</p> <p>Current controlled trials ISRCTN39851689</p

Opinion dynamics: models, extensions and external effects

Recently, social phenomena have received a lot of attention not only from social scientists, but also from physicists, mathematicians and computer scientists, in the emerging interdisciplinary field of complex system science. Opinion dynamics is one of the processes studied, since opinions are the drivers of human behaviour, and play a crucial role in many global challenges that our complex world and societies are facing: global financial crises, global pandemics, growth of cities, urbanisation and migration patterns, and last but not least important, climate change and environmental sustainability and protection. Opinion formation is a complex process affected by the interplay of different elements, including the individual predisposition, the influence of positive and negative peer interaction (social networks playing a crucial role in this respect), the information each individual is exposed to, and many others. Several models inspired from those in use in physics have been developed to encompass many of these elements, and to allow for the identification of the mechanisms involved in the opinion formation process and the understanding of their role, with the practical aim of simulating opinion formation and spreading under various conditions. These modelling schemes range from binary simple models such as the voter model, to multi-dimensional continuous approaches. Here, we provide a review of recent methods, focusing on models employing both peer interaction and external information, and emphasising the role that less studied mechanisms, such as disagreement, has in driving the opinion dynamics. [...]Comment: 42 pages, 6 figure

Effect of personal exposure to black carbon on changes in allergic asthma gene methylation measured 5 days later in urban children: importance of allergic sensitization

Background Asthma gene DNA methylation may underlie the effects of air pollution on airway inflammation. However, the temporality and individual susceptibility to environmental epigenetic regulation of asthma has not been fully elucidated. Our objective was to determine the timeline of black carbon (BC) exposure, measured by personal sampling, on DNA methylation of allergic asthma genes 5 days later to capture usual weather variations and differences related to changes in behavior and activities. We also sought to determine how methylation may vary by seroatopy and cockroach sensitization and by elevated fractional exhaled nitric oxide (FeNO). Methods Personal BC levels were measured during two 24-h periods over a 6-day sampling period in 163 New York City children (age 9–14 years), repeated 6 months later. During home visits, buccal cells were collected as noninvasive surrogates for lower airway epithelial cells and FeNO measured as an indicator of airway inflammation. CpG promoter loci of allergic asthma genes (e.g., interleukin 4 (IL4), interferon gamma (IFNγ), inducible nitric oxide synthase (NOS2A)), arginase 2 (ARG2)) were pyrosequenced at the start and end of each sampling period. Results Higher levels of BC were associated with lower methylation of IL4 promoter CpG−48 5 days later. The magnitude of association between BC exposure and demethylation of IL4 CpG−48 and NOS2A CpG+5099 measured 5 days later appeared to be greater among seroatopic children, especially those sensitized to cockroach allergens (RR [95% CI] 0.55 [0.37–0.82] and 0.67 [0.45–0.98] for IL4 CpG−48 and NOS2A CpG+5099, respectively), compared to non-sensitized children (RR [95% CI] 0.87 [0.65–1.17] and 0.95 [0.69–1.33] for IL4 CpG−48 and NOS2A CpG+5099, respectively); however, the difference was not statistically different. In multivariable linear regression models, lower DNA methylation of IL4 CpG−48 and NOS2A CpG+5099 were associated with increased FeNO. Conclusions Our results suggest that exposure to BC may exert asthma proinflammatory gene demethylation 5 days later that in turn may link to airway inflammation. Our results further suggest that seroatopic children, especially those sensitized to cockroach allergens, may be more susceptible to the effect of acute BC exposure on epigenetic changes