Exercise-based injury prevention for community-level adolescent pace bowlers

Sporting injuries are on the rise and wide-scale injury prevention strategies are needed in community-level sport. Research indicates that community-level adolescent pace bowlers could benefit from exercise-based injury prevention programs (IPPs), however, a specific program for this group has not been developed. The primary aim of this thesis was to therefore develop a specific IPP for community-level adolescent pace bowlers and investigate if this program could modify risk factors for injury in this population. The Translating Research into Injury Prevention Practice (TRIPP) framework guided the progression of studies in this thesis. In Chapter 2, risk factors for injury in adolescent pace bowlers were systematically reviewed. The review included all experimental and observational studies that reported risk factors for non-contact injuries in pace bowlers aged 12-19 years. The Newcastle-Ottawa Quality Assessment Scale was used to assess risk of bias. In Chapter 3 the various barriers and facilitators to program implementation at the community-level were identified and used to guide the development of an IPP that was appropriate for community-level adolescent pace bowlers. In Chapters 4 and 5 a cluster-randomised controlled trial was employed to examine the efficacy of this IPP to modify neuromuscular risk factors and alter bowling kinematics. Eligible pace bowlers from eight cricket organisations (clusters) were recruited and then randomised into either an intervention group or control group. The intervention group completed an eight-week IPP while the control continued their normal cricket activity. Either side of the eight-week intervention period all participants attend a baseline and follow-up session where measures of muscle strength, muscle endurance, dynamic neuromuscular control and bowling kinematics were assessed. The treatment effect of the IPP was estimated with linear mixed models. Chapter 2 identified several potentially modifiable risk factors for injury in adolescent pace bowlers and these included; excessive lateral trunk flexion while bowling, kinematics of pelvis and hip while bowling, reduced trunk endurance, and poor lumbo-pelvic-hip movement control. There were conflicting results amongst the studies which investigated the mixed technique, bowling workload, and quadratus lumborum asymmetry. Among the five cross-sectional studies, risk of bias was high and very high. Of the 11 cohort studies, three were rated as low risk of bias and eight as high risk of bias. With the information gathered in Chapter 2, an exercise program to modify risk factors was developed in Chapter 3. The program included exercises to improve; eccentric strength of the external shoulder rotators, hip adductor strength, eccentric hamstring strength, dynamic neuromuscular control of the lumbo-pelvic region and lower-limbs, and trunk extensor endurance. Chapter 3 also considered the various facilitators to program implementation at the community-level, and therefore included exercises that were; simple to learn, non-reliant on expensive equipment, and time-efficient. In Chapter 4 the efficacy of this newly developed IPP to modify neuromuscular risk factors was assessed. There were significant treatment effects (estimated marginal mean with 95% confidence intervals) favouring the intervention group for; isokinetic shoulder strength (90°/s) (0.05 Newton meters per kilogram (N.m/kg); 0.02 to 0.09), isokinetic hamstring strength (60°/s) (0.32 N.m/kg; 0.13 to 0.50), hip adductor strength dominant side (0.40 N.m/kg; 0.26 to 0.55) and non-dominant side (0.33 N.m/kg; 0.20 to 0.47), Star Excursion Balance Test reach distance dominant side (3.80 percent of leg length (%LL); 1.63 to 6.04) and non-dominant side (3.60 %LL; 1.43 to 5.78), and back endurance (20.4 seconds; 4.80 to 36.0). No differences were observed for isokinetic shoulder strength (180°/s) (p=0.09), isokinetic hamstring strength (180°/s) (p=0.07), lumbo-pelvic stability (p=0.90), and single leg squat knee valgus angle (dominant p=0.06, non-dominant p=0.15). In Chapter 5 there were significant treatment effects favouring the intervention group for shoulder counter-rotation (-3.75°; -7.19 to -0.32) and lateral trunk flexion relative to pelvis (-2.24°; -3.97 to -0.52). There were however, no significant between-group differences for; global angles of lateral trunk flexion at front foot contact (FFC) (1.2°; -2.5 to 4.8), global angles of lateral trunk flexion ball release (BR) (-0.5°; -3.0 to 2.0), pelvis rotation FFC (0.9°; -4.0 to 2.2), pelvis rotation BR (-1.1°; -5.7 to 3.6), front hip angle FFC (1.6°; -3.6 to 6.7), front hip angle BR (-1.6°; -5.0 to 1.9), front knee angle FFC (-1.1°; -4.5 to 2.3), front knee angle BR (1.7°; -5.6 to 9.1), or ball velocity (1.1 km/h; -7.5 to 9.7). This thesis demonstrates that the TRIPP framework can used to successfully guide the process of injury prevention in community-level adolescent pace bowlers. The IPP in this thesis was also able to modify several neuromuscular and biomechanical risk factors, however a number of measures were not altered. Future research is needed to refine the current IPP and investigate if it can reduce injury risk in a real-world setting

2dF QSO Redshift Survey

With approximately 6000 QSO redshifts,the 2dF QSO redshift survey is already the biggest complete QSO survey. The aim for the survey is to have 25000 QSO redshifts, providing an order of magnitude increase in QSO clustering statistics. We first describe the observational parameters of the 2dF QSO survey. We then describe several highlights of the survey so far, including new estimates of the QSO luminosity function and its evolution. We also review the current status of QSO clustering analyses from the 2dF data. Finally, we discuss how the complete QSO survey will be able to constrain the value of Omega_o by measuring the evolution of QSO clustering, place limits on the cosmological constant via a direct geometrical test and determine the form of the fluctuation power-spectrum out to the approximately 1000 Mpc scales only previously probed by COBE.Comment: 6 pages; to be published in Clustering at High Redshift, Marseille, June 1999, eds. A. Mazure, O. LeFevre, V. Lebru

A deep Giant Metre-wave Radio Telescope 610-MHz survey of the 1^HXMM–Newton/Chandra survey field

We present the results of a deep 610-MHz survey of the 1^HXMM–Newton/Chandra survey area with the Giant Metre-wave Radio Telescope. The resulting maps have a resolution of ~7 arcsec and an rms noise limit of 60 μJy. To a 5σ detection limit of 300 μJy, we detect 223 sources within a survey area of 64 arcmin in diameter. We compute the 610-MHz source counts and compare them to those measured at other radio wavelengths. The well-known flattening of the Euclidean-normalized 1.4-GHz source counts below ~2 mJy, usually explained by a population of starburst galaxies undergoing luminosity evolution, is seen at 610 MHz. The 610-MHz source counts can be modelled by the same populations that explain the 1.4-GHz source counts, assuming a spectral index of −0.7 for the starburst galaxies and the steep spectrum active galactic nucleus (AGN) population. We find a similar dependence of luminosity evolution on redshift for the starburst galaxies at 610 MHz as is found at 1.4 GHz (i.e. 'Q'= 2.45^(+0.3)_(−0.4))

The ecological genetics of Daphnia species.

Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1982 .L637. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.Sc.)--University of Windsor (Canada), 1982

The 2dF QSO Redshift Survey

We present preliminary results from the 2-degree Field (2dF) QSO Redshift Survey currently under way at the Anglo-Australian Telescope. This survey aims to determine the redshifts of >25000 QSOs over a redshift range of 0.3<z<3.0 with the primary goal of investigating large-scale structure in the Universe to high redshift and at very large scales (~1000h-1Mpc). We describe the photometric procedure used to select QSO candidates for spectroscopic observation. We then describe results from our first 2dF observations, which have so far measured the redshifts for over 1000 QSOs. We already find a significant detection of clustering and have also found one close pair of QSOs (separation 17'') which are gravitational lens candidates. To keep up to date with the current progress of the survey see: http://msowww.anu.edu.au/~rsmith/QSO_Survey/qso_surv.htmlComment: 5 pages Latex including 6 figures, To appear in the proceedings of "Evolution of Large Scale Structure: From Recombination to Garching", held August 199

Clustering in the 2dF QSO Redshift Survey

We present clustering results from the 2dF QSO Redshift Survey (2QZ) which currently contains over 20,000 QSOs at z<3. The two-point correlation function of QSOs averaged over the entire survey (~1.5) is found to be similar to that of local galaxies. When sub-dividing the sample as a function of redshift, we find that for an Einstein-de Sitter universe QSO clustering is constant (in comoving coordinates) over the entire redshift range probed by the 2QZ, while in a universe with Omega_0=0.3 and Lambda_0=0.7 there is a marginal increase in clustering with redshift. Sub-dividing the 2QZ on the basis of apparent magnitude we find only a slight difference between the clustering of QSOs of different apparent brightness, with the brightest QSOs having marginally stronger clustering. We have made a first measurement of the redshift space distortion of QSO clustering, with the goal of determining the value of cosmological parameters (in partcular Lambda_0) from geometric distortions. The current data do not allow us to discriminate between models, however, in combination with constraints from the evolution of mass clustering we find Omega_0=1-Lambda_0=0.23 +0.44-0.13 and beta(z~1.4)=0.39 +0.18-0.17. The full 2QZ data set will provide further cosmological constraints.Comment: 5 pages, 7 figures. Contributed to the 'Where's the Matter' conference in Marseille 25-29 June 200

Constraints on the distribution of absorption in the X-ray selected AGN population found in the 13H XMM-Newton/Chandra deep field

We present an analysis of the X-ray properties of sources detected in the 13H XMM-Newton deep (200ks) field. In order to constrain the absorbed AGN population, we use extensive Monte Carlo simulations to directly compare the X-ray colours of observed sources with those predicted by several model distributions. We have tested the simplest form of the AGN unified scheme, whereby the intrinsic XLF of absorbed AGN is set to be the same as that of their unabsorbed brethren, coupled with various model distributions of absorption. The best fitting of these models sets the fraction of AGN with absorbing column NH, proportional to (logNH)^8. We have also tested two extensions to the unified scheme: an evolving absorption scenario, and a luminosity dependent model distribution. Both of these provide poorer matches to the observed X-ray colour distributions than the best fitting simple unified model. We find that a luminosity dependent density evolution XLF reproduces poorly the 0.5-2 keV source counts seen in the 13H field. Field to field variations could be the cause of this disparity. Computing the simulated X-ray colours with a simple absorbed power-law + reflection spectral model is found to over-predict, by a factor of two, the fraction of hard sources that are completely absorbed below 0.5 keV, implying that an additional source of soft-band flux must be present for a number of the absorbed sources. Finally, we show that around 40% of the 13H sample are expected to be AGN with NH>10^22 cm^-2.Comment: 13 pages, 9 figures, Accepted for publication in MNRA

The polar ring galaxy AM1934-563 revisited

We report long-slit spectroscopic observations of the dust-lane polar-ring galaxy AM1934-563 obtained with the Southern African Large Telescope (SALT) during its performance-verification phase. The observations target the spectral region of the Ha, [NII] and [SII] emission-lines, but show also deep NaI stellar absorption lines that we interpret as produced by stars in the galaxy. We derive rotation curves along the major axis of the galaxy that extend out to about 8 kpc from the center for both the gaseous and the stellar components, using the emission and absorption lines. We derive similar rotation curves along the major axis of the polar ring and point out differences between these and the ones of the main galaxy. We identify a small diffuse object visible only in Ha emission and with a low velocity dispersion as a dwarf HII galaxy and argue that it is probably metal-poor. Its velocity indicates that it is a fourth member of the galaxy group in which AM1934-563 belongs. We discuss the observations in the context of the proposal that the object is the result of a major merger and point out some observational discrepancies from this explanation. We argue that an alternative scenario that could better fit the observations may be the slow accretion of cold intergalactic gas, focused by a dense filament of galaxies in which this object is embedded (abridged).Comment: 19 pages, 13 figures, submitted to MNRAS. Some figures were bitmapped to reduce the size. Full resolution version is available from http://www.saao.ac.za/~akniazev/pub/AM1934_563.pd

The 2dF QSO Redshift Survey - 10K@2K!

With ~10000 QSO redshifts, the 2dF QSO Redshift Survey (2QZ) is already the biggest individual QSO survey. The aim for the survey is to have ~25000 QSO redshifts, providing an order of magnitude increase in QSO clustering statistics. We first describe the observational parameters of the 2dF QSO survey. We then describe several highlights of the survey so far; we present new estimates of the QSO luminosity function and the QSO correlation function. We also present the first estimate of the QSO power spectrum from the 2QZ catalogue, probing the form of the fluctuation power-spectrum out to the \~1000h-1Mpc scales only previously probed by COBE. We find a power spectrum which is steeper than the prediction of standard CDM and more consistent with the prediction of Lambda-CDM. The best-fit value for the power spectrum shape parameter for a range of cosmologies is Gamma=0.1+-0.1. Finally, we discuss how the complete QSO survey will be able to constrain the value of Omega_Lambda by combining results from the evolution of QSO clustering and from a geometric test of clustering isotropy.Comment: 11 pages, 6 figures, latex, eso and springer sty files included. To appear in the proceedings of the MPA/ESO/MPA conference "Mining the Sky", Garching, July 31 - August 4 2000, eds. A.J. Banday et a