Financial signal processing: a self calibrating model

Previous work on multifactor term structure models has proposed that the short rate process is a function of some unobserved diffusion process. We consider a model in which the short rate process is a function of a Markov chain which represents the 'state of the world'. This enables us to obtain explicit expressions for the prices of zero-coupon bonds and other securities. Discretizing our model allows the use of signal processing techniques from Hidden Markov Models. This means we can estimate not only the unobserved Markov chain but also the parameters of the model, so the model is self-calibrating. The estimation procedure is tested on a selection of U.S. Treasury bills and bonds.Bonds

Sex Differences in Mechanisms of Recovery after Isometric and Dynamic Fatiguing Tasks

Purpose The purpose of this study was to determine whether supraspinal mechanisms contribute to the sex difference in fatigability during and recovery from a dynamic and isometric fatiguing task with the knee extensors. Methods: Transcranial magnetic stimulation and electrical stimulation were used to determine voluntary activation and contractile properties of the knee extensors in 14 men and 17 women (20.8 ± 1.9 yr) after a 1) 60-s sustained, maximal voluntary isometric contraction (MVIC), and 2) dynamic fatiguing task involving 120 maximal voluntary concentric contractions with a 20% MVIC load. Results: There were no differences between men and women in the reduction of maximal torque during the sustained MVIC (54.4% ± 18.9% vs 55.9% ± 11.2%, P = 0.49) or in the decrease in power during the dynamic fatiguing task (14.7% ± 20.1% vs 14.2% ± 18.5%, P = 0.92). However, MVIC torque recovered more quickly for women than men after the sustained MVIC and the dynamic task (P \u3c 0.05). The transcranial magnetic stimulation–elicited superimposed twitch was larger for men than for women during the sustained MVIC and in recovery (immediately post, R0.1: 4.7% ± 3.3% vs 2.4% ± 1.9% MVIC; P = 0.02), with no sex difference after the dynamic task (P = 0.35). The reduction in resting twitch amplitude was larger for men than for women immediately after the dynamic task (37% ± 22% vs 23% ± 18%; P = 0.016) with no sex difference after the sustained MVIC (64% ± 16% vs 67% ± 11%; P = 0.46). Conclusions: Supraspinal fatigue contributed to fatigability of the knee extensors more for men than for women after a maximal isometric task, whereas contractile mechanisms explained the sex difference in torque recovery after the fast-velocity dynamic task. The mechanisms for the sex difference in fatigability are task dependent

The feminization of the medical work force, implications for Scottish primary care: a survey of Scottish general practitioners

BACKGROUND: The number of women working in general practice internationally has been steadily rising. In Scotland there have been concerns that such a change may lead to increased part-time working and subsequently to a fall in available general practice manpower despite an apparently rising overall number of general practitioners. However, there is very little information on the actual hours worked by men and women general practitioners or on the types of work they are undertaking. METHODS: Anonymous workload questionnaires of all Scottish general practitioner principals and non-principals RESULTS: Response rates for general practice principals and non-principals were 67.2% and 65.2% respectively. Male principals spent on average 18% more time on general medical services (GMS) and 50% more time on non-GMS activities (such as teaching, specialist sessions, administration and research) than women (both p <0.01). This difference was similar for non-principals. In no age group did the hours worked by women doctors approach that of male doctors. CONCLUSION: Women doctors in primary care in Scotland work fewer hours in all age groups than their male counterparts. The rapidly increasing proportion of women in general practice may lead to an increasing shortfall of medical availability in the future if current work patterns are maintained. Further longitudinal research is required to establish this and man-power planning is required now to address this. More worryingly auxiliary activities such as teaching and administrative duties are not being taken up by women. This may have serious implications for the future development of the specialty in Scotland

Bystander intervention among secondary school pupils: testing an augmented Prototype Willingness Model

This study augmented the Prototype Willingness Model (PWM) to assess reactive and deliberative decision-making underpinning bystander intervention in gender-based violence contexts. There were 2079 participants (50% male, 49% female, 1% unreported), aged 11-15-years-old (M = 12.32, SD = 0.91), attending 19 secondary schools across Scotland. Participants self-reported the augmented PWM variables, then their intervention behaviour approximately one month later. Path analyses mostly supported the predicted relationships between positive and negative bidimensional attitudes, subjective norms, prototype perceptions, perceived behavioural control, and self-efficacy on intentions and willingness. Willingness predicted positive (speaking with a teacher) and negative (doing nothing) intervention in less serious violence. Self-efficacy predicted negative intervention in more serious violence. Subjective norms positively moderated the attitudes-intentions relationship. Overall, the results suggested that reactive (willingness) more so than deliberative (intention) decision-making account for intervention when young people witness gender-based violence. Additionally, the findings highlight the complexity of bystander intervention decision-making, where adding control perceptions, bidimensional attitudes, and moderators have independent contributions. Furthermore, self-comparison to the typical bystander who positively intervenes (prototype perceptions) was the strongest predictor of intentions and willingness, highlighting in a novel way the importance of image, and group membership on decision-making

Divergence or convergence? Health inequalities and policy in a devolved Britain

Since the advent of political devolution in the UK, it has been widely reported that markedly different health policies have emerged. However, most of these analyses are based on a comparison of health care policies and, as such, only tell part of a complex and evolving story. This paper considers official responses to a shared public health policy aim, the reduction of health inequalities, through an examination of national policy statements produced in England, Scotland and Wales respectively since 1997. The analysis suggests that the relatively consistent manner in which the ‘policy problem’ of health inequalities has been framed combined with the dominance of a medical model of health have constrained policy responses. Our findings differ from existing analyses, raising some important questions about the actuality of, and scope for, policy divergence since devolution

Interpersonal prosodic correlation in frontotemporal dementia.

Communication accommodation describes how individuals adjust their communicative style to that of their conversational partner. We predicted that interpersonal prosodic correlation related to pitch and timing would be decreased in behavioral variant frontotemporal dementia (bvFTD). We predicted that the interpersonal correlation in a timing measure and a pitch measure would be increased in right temporal FTD (rtFTD) due to sparing of the neural substrate for speech timing and pitch modulation but loss of social semantics. We found no significant effects in bvFTD, but conversations including rtFTD demonstrated higher interpersonal correlations in speech rate than healthy controls

Salt enhanced solvent relaxation and particle surface area determination via rapid spin-lattice NMR

This paper demonstrates the influence of surface charge chemistry on the application of nuclear magnetic relaxation measurements (NMR relaxometry) for the in situ determination of particle surface area, in the presence of high electrolyte concentration. Specifically, dispersions of titania, calcite and silica with and without 1 M KCl were investigated. The addition of salt, showed no significant change to relaxation measurements for titanium dioxide; however, a significant rate enhancement was observed for both calcite and silica systems. These differences were attributed to counterion layers forming as a result of the particles surface charge, leading to an increase in the relaxation rate of bound surface layer water. Further, changes appeared to be more pronounced in the silica systems, due to their larger charge. No enhancement was observed for titania, which was assumed to be due to the particles being at their isoelectric point, with no resulting counterion layer formation. Solvent relaxation was further used to successfully determine the surface area of particles in a dispersion using a silica standard reference material, with results compared to Brunauer-Emmett-Teller (BET) and spherical equivalent estimations. Two different dispersions of titanium dioxide, of different crystal phases, were shown to have NMR surface area measurements in good agreement with BET. Thus showing the technique was able to measure changes in surface charge when surface chemistry remained relatively similar, due to the reference silica material also being an oxide. In contrast, the NMR technique appeared to overestimate the calcite surface areas in reference to BET, which was assumed to occur due to both better dispersion in the liquid state of nanocrystallites and potential ion enhancement from the solubility of the calcite. These results highlight the potential of this technique as a fast, non-destructive and non-invasive method for dispersion analysis, but also show the competition between surface area and surface chemistry interactions on measured relaxation rates

Design of quadrature rules for Müntz and Müntz-logarithmic polynomials using monomial transformation

A method for constructing the exact quadratures for Müntz and Müntz-logarithmic polynomials is presented. The algorithm does permit to anticipate the precision (machine precision) of the numerical integration of Müntz-logarithmic polynomials in terms of the number of Gauss-Legendre (GL) quadrature samples and monomial transformation order. To investigate in depth the properties of classical GL quadrature, we present new optimal asymptotic estimates for the remainder. In boundary element integrals this quadrature rule can be applied to evaluate singular functions with end-point singularity, singular kernel as well as smooth functions. The method is numerically stable, efficient, easy to be implemented. The rule has been fully tested and several numerical examples are included. The proposed quadrature method is more efficient in run-time evaluation than the existing methods for Müntz polynomial