8,319 research outputs found
Implicit Bayesian Inference Using Option Prices
A Bayesian approach to option pricing is presented, in which posterior inference about the underlying returns process is conducted implicitly via observed option prices. A range of models allowing for conditional leptokurtosis, skewness and time-varying volatility in returns are considered, with posterior parameter distributions and model probabilities backed out from the option prices. Models are ranked according to several criteria, including out-of-sample fit, predictive and hedging performance. The methodology accommodates heteroscedasticity and autocorrelation in the option pricing errors, as well as regime shifts across contract groups. The method is applied to intraday option price data on the S&P500 stock index for 1995. Whilst the results provide support for models which accommodate leptokurtosis, no one model dominates according to all criteria considered.Bayesian Option Pricing; Leptokurtosis; Skewness; GARCH Option Pricing; Option Price Prediction; Hedging Errors.
Chiral discrimination in optical binding
The laser-induced intermolecular force that exists between two or more particles in the presence of an electromagnetic field is commonly termed “optical binding.” Distinct from the single-particle forces that are at play in optical trapping at the molecular level, the phenomenon of optical binding is a manifestation of the coupling between optically induced dipole moments in neutral particles. In other, more widely known areas of optics, there are many examples of chiral discrimination—signifying the different response a chiral material has to the handedness of an optical input. In the present analysis, extending previous work on chiral discrimination in optical binding, a mechanism is identified using a quantum electrodynamical approach. It is shown that the optical binding force between a pair of chiral molecules can be significantly discriminatory in nature, depending upon both the handedness of the interacting particles and the polarization of the incident light, and it is typically several orders of magnitude larger than previously reported
Validation of chronic obstructive pulmonary disease recording in the Clinical Practice Research Datalink (CPRD-GOLD)
Objectives: The optimal method of identifying people with chronic obstructive pulmonary disease (COPD) from electronic primary care records is not known. We assessed the accuracy of different approaches using the Clinical Practice Research Datalink, a UK electronic health record database. Setting: 951 participants registered with a CPRD practice in the UK between 1 January 2004 and 31 December 2012. Individuals were selected for ≥1 of 8 algorithms to identify people with COPD. General practitioners were sent a brief questionnaire and additional evidence to support a COPD diagnosis was requested. All information received was reviewed independently by two respiratory physicians whose opinion was taken as the gold standard. Primary outcome measure: The primary measure of accuracy was the positive predictive value (PPV), the proportion of people identified by each algorithm for whom COPD was confirmed. Results: 951 questionnaires were sent and 738 (78%) returned. After quality control, 696 (73.2%) patients were included in the final analysis. All four algorithms including a specific COPD diagnostic code performed well. Using a diagnostic code alone, the PPV was 86.5% (77.5-92.3%) while requiring a diagnosis plus spirometry plus specific medication; the PPV was slightly higher at 89.4% (80.7-94.5%) but reduced case numbers by 10%. Algorithms without specific diagnostic codes had low PPVs (range 12.2-44.4%). Conclusions: Patients with COPD can be accurately identified from UK primary care records using specific diagnostic codes. Requiring spirometry or COPD medications only marginally improved accuracy. The high accuracy applies since the introduction of an incentivised disease register for COPD as part of Quality and Outcomes Framework in 2004
Exercise interventions for preventing dementia or delaying cognitive decline in people with mild cognitive impairment
This is the protocol for a review and there is no abstract. The objectives are as follows: To evaluate the effects of exercise interventions for preventing dementia in people with mild cognitive impairment. We refer to Forbes 2015b and Forbes 2015c for the review protocols on exercise interventions for maintaining cognitive function in cognitively healthy people in mid and late life
Exercise interventions for maintaining cognitive function in cognitively healthy people in mid life
This is the protocol for a review and there is no abstract. The objectives are as follows: To evaluate the effects ofexercise interventions on cognitive function in cognitively healthy people in mid life. We refer to Forbes 2015b for the review protocol on Exercise interventions for maintaining cognitive function in cognitively healthy people in late life and to Forbes 2015c for the review protocol on Exercise interventions for prevention of dementia in people with mild cognitive impairment
Matchmaker, Matchmaker, Make me a Match: Does Cognitive Style Make a Difference?
The question of how to better match students’ individual learning capabilities with instructional modalities, with a view to improving student performance, has increasingly attracted researcher and educator attention. Consistent with this trend, a team of faculty from the College of Arts, Sciences and Technology at Franklin University conducted a study that investigated whether differences between instructor and student learning styles may account for performance disparities as well as how students might perform differently as a result of their individual learning preferences. The research sample consisted of 161 college students attending a basic statistics course. Instructor and student learning styles, using the Learning Style Inventory (LSI), as well as students’ course grades, were collected and analyzed over the course of a year.
Study results indicated that there was insufficient evidence to support the hypothesis that students’ performance differs significantly as to whether (or to what degree) their learning styles matches that of their instructors. However, the data did suggest that two different learning style groups do appear to perform differently and that the LSI may be sensitive on select learning dimensions. Information in this poster should support educators who give attention to the feeling and doing dimensions of learning when planning instructional activities.https://fuse.franklin.edu/ss2014/1014/thumbnail.jp
NMR shim coil design utilising a rapid spherical harmonic calculation method
A rapid spherical harmonic calculation method is used for the design of Nuclear Magnetic Resonance shim coils. The aim is to design each shim such that it generates a field described purely by a single spherical harmonic. By applying simulated annealing techniques, coil arrangements are produced through the optimal positioning of current-carrying circular arc conductors of rectangular cross-section. This involves minimizing the undesirable harmonies in relation to a target harmonic. The design method is flexible enough to be applied for the production of coil arrangements that generate fields consisting significantly of either zonal or tesseral harmonics. Results are presented for several coil designs which generate tesseral harmonics of degree one
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