A study of longitudianl oscillations of propellant tanks and wave propagations in feed lines. Part IV - Longitudinal oscillation of a propellant-filled flexible hemispherical tank

Longitudinal oscillation of propellant-filled flexible hemispherical tan

A study of longitudinal oscillations of propellant tanks and wave propagations in feed lines. Part I - One-dimensional wave propagation in a feed line

Longitudinal oscillations of propellant tanks and wave propagations in feed lines with streaming flui

Hamstring strain injuries: incidence, mechanisms, risk factors and training recommendations

Hamstring strain injury (HSI) is one of the most commonly reported sports injuries. This has led to a substantial amount of research aimed at identifying factors that increase the risk of an athlete suffering a HSI. The identification of risk factors allows practitioners to plan intervention programmes with the aim of reducing the rate and severity of HSI. As a multitude of factors contribute to the risk of HSI, interventions should be multifaceted in nature. This review outlines the incidence, mechanisms and risk factors for HSI and provides evidence-based training recommendations to reduce the rate and severity of HSI

Equi-energy sampler with applications in statistical inference and statistical mechanics

We introduce a new sampling algorithm, the equi-energy sampler, for efficient statistical sampling and estimation. Complementary to the widely used temperature-domain methods, the equi-energy sampler, utilizing the temperature--energy duality, targets the energy directly. The focus on the energy function not only facilitates efficient sampling, but also provides a powerful means for statistical estimation, for example, the calculation of the density of states and microcanonical averages in statistical mechanics. The equi-energy sampler is applied to a variety of problems, including exponential regression in statistics, motif sampling in computational biology and protein folding in biophysics.Comment: This paper discussed in: [math.ST/0611217], [math.ST/0611219], [math.ST/0611221], [math.ST/0611222]. Rejoinder in [math.ST/0611224]. Published at http://dx.doi.org/10.1214/009053606000000515 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Bayesian field theoretic reconstruction of bond potential and bond mobility in single molecule force spectroscopy

Quantifying the forces between and within macromolecules is a necessary first step in understanding the mechanics of molecular structure, protein folding, and enzyme function and performance. In such macromolecular settings, dynamic single-molecule force spectroscopy (DFS) has been used to distort bonds. The resulting responses, in the form of rupture forces, work applied, and trajectories of displacements, have been used to reconstruct bond potentials. Such approaches often rely on simple parameterizations of one-dimensional bond potentials, assumptions on equilibrium starting states, and/or large amounts of trajectory data. Parametric approaches typically fail at inferring complex-shaped bond potentials with multiple minima, while piecewise estimation may not guarantee smooth results with the appropriate behavior at large distances. Existing techniques, particularly those based on work theorems, also do not address spatial variations in the diffusivity that may arise from spatially inhomogeneous coupling to other degrees of freedom in the macromolecule, thereby presenting an incomplete picture of the overall bond dynamics. To solve these challenges, we have developed a comprehensive empirical Bayesian approach that incorporates data and regularization terms directly into a path integral. All experiemental and statistical parameters in our method are estimated empirically directly from the data. Upon testing our method on simulated data, our regularized approach requires fewer data and allows simultaneous inference of both complex bond potentials and diffusivity profiles.Comment: In review - Python source code available on github. Abridged abstract on arXi

The importance of strength and power on key performance indicators in elite youth soccer

The purpose of this investigation was to examine the importance of strength and power in relation to key performance indicators (KPI’s) within competitive soccer match play. This was achieved through using an experimental approach where fifteen subjects were recruited from a professional soccer club’s scholarship squad during the 2013/14 season. Following anthropometric measures, power and strength were assessed across a range of tests which included the squat jump (SJ), countermovement jump (CMJ), 20 metre (m) sprint and arrowhead change of direction test. A predicted 1-repetition maximum (RM) was also obtained for strength by performing a 3RM test for both the back squat and bench press and a total score of athleticism (TSA) was provided by summing z-scores for all fitness tests together, providing one complete score for athleticism. Performance analysis data was collected during 16 matches for the following KPIs: passing, shooting, dribbling, tackling and heading. Alongside this, data concerning player ball involvements (touches) was recorded. Results showed that there was a significant correlation (p < 0.05) between CMJ (r = 0.80), SJ (r = 0.79) and TSA (r = 0.64) in relation to heading success. Similarly, a significant correlation (p < 0.05) between predicted 1RM squat strength and tackle success (r = 0.61). These data supports the notion that strength and power training are important to soccer performance, particularly when players are required to win duels of a physical nature. There were no other relationships found between the fitness data and the KPI’s recorded during match play which may indicate that other aspects of player’s development such as technical skill, cognitive function and sensory awareness are more important for soccer-specific performance

Prompting Procedure Skill Acquisition: The Role of Performance Feedback

There is a need for educators to implement evidence-based treatments for children with autism. Effective training of professionals is essential in ensuring treatment is implemented with integrity. Behavioral Skills Training (BST), an efficacious staff training method, identifies feedback as a critical component of training; however, the role of feedback in this process has not been systematically examined. This research evaluates the efficiency at which prompting skills are acquired, the accuracy at which prompting skills are maintained one-week post acquisition, and the acceptability of training experience across individuals who received either performance feedback or general feedback following brief, video BST

Illumination uniformity in endoscopic imaging

Standardised endoscopic digital images were taken and analysed using an image analysis software (National Instruments Vision Assistant version 7.1.1). The luminance plane was extracted and the pixel intensity distribution was determined along a horizontal line at the position of highest average intensity (centroid). The data was exported to MS Excel and the pixel intensity (y-axis) was plotted against pixel position (x-axis). A trendline using a 2nd order polynomial curve was fitted to each data set. The resultant equation for each curve was compared with equations obtained from other images taken under various illumination conditions and settings

Investigation of dynamic stresses in detona- tion technical note no. 7

Axial and hoop stress calculation in blast loaded thin walled cylindrical pressure vessel

The Impact of Oil and Natural Gas Facilities on Rural Residential Property

This paper examines the impact of oil and gas facilities on rural residential property values using data from central Alberta, Canada. The influences are evaluated using two groups of variables characterizing hazard effects and amenity effects. A spatial error model was employed to capture the spatial dependence between neighbouring properties. The results show that property values are negatively correlated with the number of sour gas wells and flaring oil batteries within 4km of the property. Indices reflecting potential health hazards associated with rates of H2 S release (based on information from Emergency Response Plans and Zones) also have a significant negative association with property prices. The findings suggest that oil and sour gas facilities located within 4 km of rural residential properties significantly affect their sale price.sour gas; hedonic prices; property value impacts