Cricket bowling: A two-segment Lagrangian model

In this study, a Lagrangian forward solution of the bowling arm in cricket is made using a two-segment rigid body model, coupled with projectile equations for the free flight of the ball. For given initial arm positions and constant joint torques, the equations are solved numerically to determine the ball speed and arm angle at release so that the ball can land on a predetermined position on the pitch. The model was driven with kinematic data from video obtained from an elite bowler. The model can be analysed in order to study the biomechanics of the bowling arm as well as to quantify the effects of changing input parameters on the trajectory and speed of the ball

Spatial and temporal variations in the occurrence of low flow events in the UK

International audienceInformation on the magnitude and variability of low river flows at the river reach scale is central to most aspects of water resource and water quality management. Within the UK, river stretches with permanent gauging stations represent less than one percent of the total number of river stretches mapped at a scale of 1:50,000 and fewer that 20% of gauged catchments can be regarded as having natural flow regimes. This has led to the development of simple, multivariate models for predicting average annual natural flow duration statistics through relationships with catchment characteristics. One assumption within these models is that low flows occur at the same time at all points within a catchment, irrespective of the hydrogeological nature and climatic condition of the catchment. This paper discusses the implications of spatial variations in the timing of low flow events for this type of model. Differences in the timing of the mean day of occurrence of the annual Q95 flow in UK catchments can be identified with low flows occurring earlier in the year within impermeable dry catchments and later in the year for wet permeable catchments. However, any differences in the mean day of occurrence between different catchments are generally masked by the magnitude of the inter-year variability in the day of occurrence. From analysis of linear combinations of flow statistics from nearest-neighbour gauged catchments, the paper demonstrates that the assumption of temporal coherence of low flows will generally result in an under-estimate of Q95; these underestimates are more significant for pairs of impermeable catchments than for combinations of permeable catchments and impermeable-permeable catchments

Relativity principles in 1+1 dimensions and differential aging reversal

We study the behavior of clocks in 1+1 spacetime assuming the relativity principle, the principle of constancy of the speed of light and the clock hypothesis. These requirements are satisfied by a class of Finslerian theories parametrized by a real coefficient $\beta$, special relativity being recovered for $\beta=0$. The effect of differential aging is studied for the different values of $\beta$. Below the critical values $|\beta| =1/c$ the differential aging has the usual direction - after a round trip the accelerated observer returns younger than the twin at rest in the inertial frame - while above the critical values the differential aging changes sign. The non-relativistic case is treated by introducing a formal analogy with thermodynamics.Comment: 12 pages, no figures. Previous title "Parity violating terms in clocks' behavior and differential aging reversal". v2: shortened introduction, some sections removed, pointed out the relation with Finsler metrics. Submitted to Found. Phys. Let

An Internet "Value of Health" panel: recruitment, participation and compliance

OBJECTIVES To recruit a panel of members of the public to provide preferences in response to the needs of economic evaluators over the course of a year. METHODS A sample of members of the UK general public was recruited in a stratified random sample from the electoral roll and familiarised with the standard gamble method of preference elicitation using an internet based tool. Recruitment (proportion of people approached who were trained), participation (defined as the proportion of people trained who provided any preferences) and compliance (defined as the proportion of preference tasks which were completed) were described. The influence of covariates on these outcomes were investigated using univariate and multivariate analyses. RESULTS A panel of 112 people was recruited. The eventual panel reflected national demographics to some extent, but recruitment from areas of high socioeconomic deprivation and among ethnic minority communities was low. 23% of people who were approached (n= 5,320) responded to the invitation to take part in the study, and 24% of respondents (n=1,215) were willing to participate. However, eventual recruitment rates, following training, were low (2.1% of those approached), although significantly higher in Exeter than other cities. 18 sets of health state descriptions were presented to the panel over 14 months. 74% of panel members praticipated in at least one valuation task. Socioeconomic and marital status were significantly associated with participation. Compliance varied from 3% to 100%, with the average per set of health state descriptions being 41%. Compliance was higher in retired people but otherwise no significant predictors were identified. CONCLUSIONS It is feasible to recruit and train a panel of members of the general public to express preferences on a wide range of health states using the internet in response to the needs of analysts. In order to provide a sample which reflects the demographics of the general public, and capitalise on the increasing opportunities for the use of the internet in this field, over-sampling in areas of high socioeconomic deprivation and among ethnic minority communities is necessary

An Internet “Value of Health” panel: recruitment, participation and compliance

OBJECTIVES To recruit a panel of members of the public to provide preferences in response to the needs of economic evaluators over the course of a year. METHODS A sample of members of the UK general public was recruited in a stratified random sample from the electoral roll and familiarised with the standard gamble method of preference elicitation using an internet based tool. Recruitment (proportion of people approached who were trained), participation (defined as the proportion of people trained who provided any preferences) and compliance (defined as the proportion of preference tasks which were completed) were described. The influence of covariates on these outcomes was investigated using univariate and multivariate analyses. RESULTS A panel of 112 people was recruited. The eventual panel reflected national demographics to some extent, but recruitment from areas of high socioeconomic deprivation and among ethnic minority communities was low. 23% of people who were approached (n= 5,320) responded to the invitation to take part in the study, and 24% of respondents (n=1,215) were willing to participate. However, eventual recruitment rates, following training, were low (2.1% of those approached), although significantly higher in Exeter than other cities. 18 sets of health state descriptions were presented to the panel over 14 months. 74% of panel members praticipated in at least one valuation task. Socioeconomic and marital status were significantly associated with participation. Compliance varied from 3% to 100%, with the average per set of health state descriptions being 41%. Compliance was higher in retired people but otherwise no significant predictors were identified. CONCLUSIONS It is feasible to recruit and train a panel of members of the general public to express preferences on a wide range of health states using the internet in response to the needs of analysts. In order to provide a sample which reflects the demographics of the general public, and capitalise on the increasing opportunities for the use of the internet in this field, over-sampling in areas of high socioeconomic deprivation and among ethnic minority communities is necessary.utility; Internet; public; survey

Ultra-structural analysis of breast tissue

Previous research has shown that diagnostic information could be obtained from small angle X-ray scattering from breast tissues. The observed differences were attributed to two possible causes, the production of a new type of collagen around tumours and the action of matrix metalloproteinases degrading the collagen around tumours. Using both synchrotron radiation and conventional X-ray sources data was collected to investigate these hypotheses. 225 X-ray scattering profiles were collected from breast tissue samples from 82 individual patients using synchrotron radiation. The differences between normal, malignant and benign tissues were investigated and structural differences in the collagen were determined. The effects of metalloproteinase action on collagen were also investigated and computer modelling was used to simulate the diffraction profiles from collagen with structural alterations. The structural differences in diseased tissues were attributed to a difference in the structure of collagen which was observed as a reduction in peak intensity and increased axial D spacing (0.3 nm increase in D period) compared to normal tissues. The differences between malignant and benign disease were attributed to metalloproteinase action degrading the collagen around tumours. Automatic classification was applied using principal component analysis to tissue samples from up to 6 cm away from the tumour site, approximately 90 % of the tissue samples at 6 cm were classified as cancer using the X-ray scattering profile but which were diagnosed as normal by standard histopathological methods. The results of this research have shown that X-ray scattering profiles contain diagnostic information relating to the structure of collagen. The changes associated with disease may be observed at up to 6 cm from the tumour site and that these differences in the X-ray scattering profile may be measured using a conventional X-ray source.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

3D atomic structure from a single XFEL pulse

X-ray Free Electron Lasers (XFEL) are the most advanced pulsed x-ray sources. Their extraordinary pulse parameters promise unique applications. Indeed, several new methods have been developed at XFEL-s. However, no methods are known, which would allow ab initio atomic level structure determination using only a single XFEL pulse. Here, we present experimental results, demonstrating the determination of the 3D atomic structure from data obtained during a single 25 fs XFEL pulse. Parallel measurement of hundreds of Bragg reflections was done by collecting Kossel line patterns of GaAs and GaP. With these measurements, we reached the ultimate temporal limit of the x-ray structure solution possible today. These measurements open the way for studying non-repeatable fast processes and structural transformations in crystals for example measuring the atomic structure of matter at extremely non-ambient conditions or transient structures formed in irreversible physical, chemical, or biological processes. It would also facilitate time resolved pump-probe structural studies making them significantly shorter than traditional serial crystallography.Comment: 16 pages of manuscript followed by 15 pages of supplementary informatio

Total ankle replacement versus arthrodesis (TARVA): protocol for a multicentre randomised controlled trial.

INTRODUCTION: Total ankle replacement (TAR) or ankle arthrodesis (fusion) is the main surgical treatments for end-stage ankle osteoarthritis (OA). The popularity of ankle replacement is increasing while ankle fusion rates remain static. Both treatments have efficacy but to date all studies comparing the 2 have been observational without randomisation, and there are no published guidelines as to the most appropriate management. The TAR versus arthrodesis (TARVA) trial aims to compare the clinical and cost-effectiveness of TAR against ankle arthrodesis in the treatment of end-stage ankle OA in patients aged 50-85 years. METHODS AND ANALYSIS: TARVA is a multicentre randomised controlled trial that will randomise 328 patients aged 50-85 years with end-stage ankle arthritis. The 2 arms of the study will be TAR or ankle arthrodesis with 164 patients in each group. Up to 16 UK centres will participate. Patients will have clinical assessments and complete questionnaires before their operation and at 6, 12, 26 and 52 weeks after surgery. The primary clinical outcome of the study is a validated patient-reported outcome measure, the Manchester Oxford foot questionnaire, captured preoperatively and 12 months after surgery. Secondary outcomes include quality-of-life scores, complications, revision, reoperation and a health economic analysis. ETHICS AND DISSEMINATION: The protocol has been approved by the National Research Ethics Service Committee (London, Bloomsbury 14/LO/0807). This manuscript is based on V.5.0 of the protocol. The trial findings will be disseminated through peer-reviewed publications and conference presentations. TRIAL REGISTRATION NUMBER: NCT02128555