Conservation genetics of sauger in the upper Missouri River drainage

Hybridization with non-native walleye may play a substantial role in sauger declines throughout the upper Missouri River drainage of Montana and Wyoming. I identified 11 microsatellite loci to detect interspecific hybridization and describe the genetic population structure of sauger. Two major population groupings of sauger were revealed by principal component analysis. The first consisted of samples from the Missouri and lower Yellowstone River drainages, which showed no evidence for genetic divergence among each other. The second major grouping contained samples from the Bighorn River drainage and the upper Yellowstone River. Samples from the upper Bighorn River drainage were genetically distinct from downstream samples. The Bighorn and upper Yellowstone River samples had substantially lower heterozygosity and allelic richness than the lower Yellowstone and Missouri River samples. Analysis of simulated data sets suggested that 100% of sauger and walleye and 100% of first and second generation hybrids could be correctly identified using these 11 loci. This indicates that my analysis method has the power to discriminate sauger and walleye and to detect hybridization and introgression. I detected only eighteen hybrids out of 925 individuals analyzed. Hybridization appeared recent, as nearly 50% of the hybrids showed significant evidence for having a non-hybrid ancestor within two generations. Only one hybrid was detected in the Missouri River. All others were found in the Yellowstone River drainage, despite a substantially higher rate of walleye stocking in the Missouri River drainage. Environmental conditions in the Yellowstone River drainage may be more conducive to hybridization, or hybrid and walleye survival. The rarity of hybrids, despite massive walleye stocking, is unexpected. Introgression of walleye genes into native sauger does not appear to be an immediate threat. Nevertheless, the presence of hybrids could still be harmful because their production represents wasted reproductive effort. Given my results, I recommend that (1) the transfer of genetically distinct stocks of sauger not take place; (2) historical levels of gene flow among populations be restored; and (3) the walleye fishery in the upper Missouri River drainage be replaced with a sauger or sterile walleye fishery

The measurement, levels, and correlates of physical activity in a bi-ethnic population of young children

Background: The first five years of life, called the early years is a period of rapid and vital physical, behavioural, emotional and social development. Physical activity (PA) is one of the behaviours which develop during the early years, and high levels of PA during the early years have been shown to be related to multiple health outcomes. The importance of PA of young children (children during the early years) has been highlighted by a number of national governments. In order to better inform future interventions and public health policies, a greater understanding of the correlates and determinants of young children s PA is vital. Previous research has been limited through measurement inconsistencies, and few studies have been conducted within multi-ethnic communities, where many young children in the United Kingdom are born. Thesis Aims: 1) to systematically review published research in order to establish currently known correlates and determinants of PA in the early years and identify gaps within the literature. 2) Calculate an accelerometer wear-time criteria to reliably measure young children s habitual PA. 3) Investigate the validity and test re-test reliability of a new parental proxy reported PA questionnaire. 4) Investigate the levels and correlates of moderate-to-vigorous PA (MVPA) in toddlers (1-3 year olds) from a predominately bi-ethnic and bi-linguistic population. Methods: Aim 1) nine electronic databases were searched to identify previous research which investigated associations between an exposure/variable, and a quantitative measure of PA. Correlates/determinants of total PA (TPA), MVPA and light-intensity PA (LPA) were reported using an ecologic model. Aim 2) to calculate a wear-time criteria for young children a simple stepped process was used whereby statistical tests were run to determine the minimum length of wear for one day, if there were any differences between weekdays and weekend days, and the presence of reactivity. Intra-class correlation models and the Spearman-Brown prophecy formula were used to calculate wear-time reliability. Aim 3) this study was undertaken by 196 parents completing a proxy report questionnaire on their child s PA and sedentary behaviour after seven days of their young child (mean age 3.2 ,SD: 0.8 years) wearing an accelerometer. A total of 156 (79.6%) questionnaires were completed in English and 40 (20.4%) were completed in transliterated Urdu. Of the 196 parents, 109 parents completed the EY-PAQ a second time seven days apart from the first EY-PAQ completion; this was to assess test re-test reliability of MVPA and sedentary time. Validity analysis used all data and data falling with specific proportion boundaries for MVPA (2%-41%) and sedentary time (30%-94%). Reliability was assessed using intra-class correlations (ICC) and validity by Bland Altman plots and rank correlation coefficients. Aim 4) this study was undertaken by conducting a cross-sectional analysis using 24 month olds and their mothers data collected as part of the Born in Bradford (BiB) birth cohort sub-sample study called BiB1000. The outcome variable was daily minutes of MVPA measured by the EY-PAQ. Numerous independent variables covering the layers of an ecological model were selected. Univariate linear regression models accounting for sex, age, language and season were conducted to examine the differences between White British and South Asian children s daily minutes of MVPA and each of the EY-PAQ s domains, and the proportion of time spent in MVPA within each of the EY-PAQ s domains. A series of univariate linear regression analyses were performed to examine and identify correlates of MVPA (for the whole sample, and separately for White British and South Asian children). Significant variables found in univariate analyses were then included in hierarchical multivariable regression models (based upon the ecological model), in order to examine the percentage of variance accounted for in daily minutes of MVPA. Results: Aim 1) The systematic review identified a large volume of published research. All studies took place in high income countries and few studies (6%) were of high quality. A small number of correlates and determinants of TPA were identified. The only correlate of MVPA was sex and no determinants of MVPA or LPA were found. PA correlates/ determinants were relatively consistent between objective and subjective PA measures and few studies investigated correlates of toddlers or between children with White and South Asian ethnicity. Aim 2) No differences in accelerometer-determined time in TPA, MVPA or sedentary time were observed between weekdays and weekend days within this sample of young children. Similarly, there was no evidence of reactivity to accelerometer use. For young children living in Bradford, an accelerometer wear-time of a minimum of six hours on any three days was shown to provide reliable estimates of accelerometer-determined time in TPA, MVPA, and sedentary time. Aim 3) The test re-test reliability of the EY-PAQ was moderate for sedentary time and fair for MVPA. The EY-PAQ had poor agreement with accelerometry with both sedentary time and MVPA before the application of boundaries. Post application of boundaries the EY-PAQ still had poor agreement with accelerometer-determined sedentary time but good agreement for MVPA. Limits of agreement were wide for all variables and language and ethnicity did not confound results. Aim 4) Bradford toddlers were found to be very active and no difference was observed between proxy-reported time spent in MVPA between White British and South Asian children. However, White British toddlers were found to have spent significantly more time in reported MVPA while walking for transport compared to South Asian toddlers; while South Asian toddlers reportedly spent significantly more time of MVPA in the home compared to White British toddlers. Correlate models were only statistically significant when multi-layers of the ecological model were included; and correlates differed for South Asian and White British children. Conclusions: There is a need for more high-quality studies exploring correlates/determinants across all layers of the ecologic model, and research investigating MVPA correlates/determinants of toddlers and between ethnicities is sparse. The work reported within this thesis has produced a reliable wear-time criterion for use to estimate accelerometer-determined PA and sedentary time in young children living in a bi-ethnic community. This criterion can now be used in future accelerometer studies (validation, observational and intervention) and the stepped-process offers researchers a method to derive sample-specific wear time criteria. The EY-PAQ is a promising habitual population-level measure of young children s MVPA from a bi-ethnic community. In situations when objective methods are not possible for measurement of young children s MVPA, the EY-PAQ may be a suitable alternative. Levels of toddlers MVPA did not differ by ethnicity but the contexts and correlates did. Therefore, future interventions should seek to maintain and maximise high levels of toddlers MVPA and tailor interventions by ethnicity. The research conducted within this thesis will inform the development of surveillance systems, interventions and public health polices to improve young children s PA levels, particularly children living in a bi-ethnic community

A comparison of GOCE and drifter-based estimates of the North Atlantic steady-state surface circulation

Over the last decade, due to the Gravity Recovery And Climate Experiment (GRACE) mission and, more recently, the Gravity and steady state Ocean Circulation Explorer (GOCE) mission, our ability to measure the ocean’s mean dynamic topography (MDT) from space has improved dramatically. Here we use GOCE to measure surface current speeds in the North Atlantic and compare our results with a range of independent estimates that use drifter data to improve small scales. We find that, with filtering, GOCE can recover 70% of the Gulf Steam strength relative to the best drifter-based estimates. In the subpolar gyre the boundary currents obtained from GOCE are close to the drifter-based estimates. Crucial to this result is careful filtering which is required to remove small-scale errors, or noise, in the computed surface. We show that our heuristic noise metric, used to determine the degree of filtering, compares well with the quadratic sum of mean sea surface and formal geoid errors obtained from the error variance–covariance matrix associated with the GOCE gravity model. At a resolution of 100 km the North Atlantic mean GOCE MDT error before filtering is 5 cm with almost all of this coming from the GOCE gravity model

Bayes One-Sample and One-Way Random Effects Analyses for 3-D Orientations with Application to Materials Science

We consider Bayes inference for a class of distributions on orientations in 3 dimensions described by 3×3 rotation matrices. Non-informative priors are identified and Metropolis-Hastings within Gibbs algorithms are used to generate samples from posterior distributions in one-sample and one-way random effects models. A simulation study investigates the performance of Bayes analyses based on non-informative priors in the one-sample case, making comparisons to quasi-likelihood inference. A second simulation study investigates the behavior of posteriors for some informative priors. Bayes one-way random effect analyses of orientation matrix data are then developed and the Bayes methods are illustrated in a materials science application

Objectively-measured sedentary time and physical activity in a bi-ethnic sample of young children : variation by socio-demographic, temporal and perinatal factors

Background: Evidence suggests that South Asian school-aged children and adults are less active compared to the white British population. It is unknown if this generalises to young children. We aimed to describe variability in levels of physical activity and sedentary time in a bi-ethnic sample of young children from a deprived location. Methods: This observational study included 202 South Asian and 140 white British children aged 1.5 to 5y, who provided 3,181 valid days of triaxial accelerometry (Actigraph GT3X+). Variability in sedentary time and physical activity levels were analysed by linear multilevel modelling. Logistic multilevel regression was used to identify factors associated with physical inactivity (failing to perform ≥180 minutes of total physical activity including ≥60 minutes moderate-to-vigorous physical activity (MVPA) per day). Results: There were no significant ethnic differences in the overall levels of behaviours; South Asian and white British children spent half of daily time sedentary, just over 40% in light physical activity, and the remaining 7.5 to 8% of time in MVPA. Sedentary time was lower and physical activity levels were higher in older children, and levels of MVPA and vector magnitude counts per minute (CPM) were higher on weekends compared to weekdays. In South Asian children, sedentary time was lower on weekends. Sedentary time was lower and physical activity levels were higher in spring compared to winter in white British children, and in all seasons compared to winter in South Asian children. South Asian children born at high birth weight performed more MVPA, and in both ethnicities there was some evidence that children with older mothers were more sedentary and less active. Sedentary time was higher and light physical activity was lower in South Asian children in the highest compared to the lowest income families. South Asian girls performed less MVPA, registered fewer vector magnitude CPM, and were 3.5 times more likely to be physically inactive than South Asian boys. Conclusions: Sedentary time and physical activity levels vary by socio-demographic, temporal and perinatal characteristics in young children from a deprived location. South Asian girls have the most to gain from efforts to increase physical activity levels

X-Ray fluorescence analysis of feldspars and silicate glass: effects of melting time on fused bead consistency and volatilisation

Reproducible preparation of lithium tetraborate fused beads for XRF analysis of glass and mineral samples is of paramount importance for analytical repeatability. However, as with all glass melting processes, losses due to volatilization must be taken into account and their effects are not negligible. Here the effects of fused bead melting time have been studied for four Certified Reference Materials (CRM’s-three feldspars, one silicate glass), in terms of their effects on analytical variability and volatilization losses arising from fused bead preparation. At melting temperatures of 1065 °C, and for feldspar samples, fused bead melting times shorter than approximately 25 minutes generally gave rise to greater deviation of XRF-analyzed composition from certified composition. This variation might be due to incomplete fusion and / or fused bead inhomogeneity but further research is needed. In contrast, the shortest fused bead melting time for the silicate glass CRM gave an XRF-analyzed composition closer to the certified values than longer melting times. This may suggest a faster rate of glass-in-glass dissolution and homogenization during fused bead preparation. For all samples, longer melting times gave rise to greater volatilization losses (including sulphates and halides) during fusion. This was demonstrated by a linear relationship between SO3 mass loss and time1/2, as predicted by a simple diffusion-based model. Iodine volatilization displays a more complex relationship, suggestive of diffusion plus additional mechanisms. This conclusion may have implications for vitrification of iodine-bearing radioactive wastes. Our research demonstrates that the nature of the sample material impacts on the most appropriate fusion times. For feldspars no less than ~25 min and no more than ~60 min of fusion at 1065 °C, using Li2B4O7 as the fusion medium and in the context of feldspar samples and the automatic fusion equipment used here, strikes an acceptable (albeit non-ideal) balance between the competing factors of fused bead quality, analytical consistency and mitigating volatilization losses. Conversely, for the silicate glass sample, shorter fusion times of less than ~30 minutes under the same conditions provided more accurate analyses whilst limiting volatile losses

A consistent scalar-tensor cosmology for inflation, dark energy and the Hubble parameter

The authors are grateful for financial support to the Cruickshank Trust (CW), EPSRC/GG-Top (CW, JR), Omani Government (MA), Science Without Borders programme, CNPq, Brazil (DR), and STFC/CfFP (CW, AM, RB, JM). CW and AM acknowledge the hospitality of CERN, where this work was started. The University of Aberdeen and University of Edinburgh are charitable bodies registered in Scotland, with respective registration numbers SC013683 and SC005336.Peer reviewedPostprin