2,283 research outputs found
Dietary Intakes of Elite 14 - 19 Year Old English Academy Rugby Players During a Pre-Season Training Period.
Good nutrition is essential for the physical development of adolescent athletes, however data on dietary intakes of adolescent rugby players are lacking. This study quantified and evaluated dietary intake in 87 elite male English academy rugby league (RL) and rugby union (RU) players by age (under-16 (U16) and under-19 (U19) years old) and code (RL and RU). Relationships of intakes with body mass and composition (sum of 8 skinfolds) were also investigated. Using 4-day diet and physical activity diaries, dietary intake was compared to adolescent sports nutrition recommendations and the UK national food guide. Dietary intake did not differ by code, whereas U19s consumed greater energy (3366 ± 658 vs. 2995 ± 774 kcal.day-1), protein (207 ± 49 vs. 150 ± 53 g.day-1) and fluid (4221 ± 1323 vs. 3137 ± 1015 ml.day-1) than U16s. U19s consumed a better quality diet than U16s (greater intakes of fruit and vegetables; 4.4 ± 1.9 vs. 2.8 ± 1.5 servings.day-1; non-dairy proteins; 3.9 ± 1.1 vs. 2.9 ± 1.1 servings.day-1) and less fats and sugars (2.0 ± 1. vs. 93.6 ± 2.1 servings.day-1). Protein intake vs. body mass was moderate (r = 0.46, p < 0.001), and other relationships were weak. The findings of this study suggest adolescent rugby players consume adequate dietary intakes in relation to current guidelines for energy, macronutrient and fluid intake. Players should improve the quality of their diet by replacing intakes from the fats and sugars food group with healthier choices, while maintaining current energy, and macronutrient intakes
Aiding the design of radiation resistant materials with multiphysics simulations of damage processes
The design of metals and alloys resistant to radiation damage involves the physics of electronic excitations and the creation of defects and microstructure. During irradiation damage of metals by high energy particles, energy is exchanged between ions and electrons. Such non-adiabatic processes violate the Born-Oppenheimer approximation, on which all conservative classical interatomic potentials rest. By treating the electrons of a metal explicitly and quantum mechanically we are able to explore the influence of electronic excitations on the ionic motion during irradiation damage. Simple theories suggest that moving ions should feel a damping force proportional to their velocity and directly opposed to it. In contrast, our simulations of a forced oscillating ion have revealed the full complexity of this force: in reality it is anisotropic and dependent on the ion velocity and local atomic environment. A large set of collision cascade simulations has allowed us to explore the form of the damping force further. We have a means of testing various schemes in the literature for incorporating such a force within molecular dynamics (MD) against our semi-classical evolution with explicitly modelled electrons. We find that a model in which the damping force is dependent upon the local electron density is superior to a simple fixed damping model. We also find that applying a lower kinetic energy cut-off for the damping force results in a worse model. A detailed examination of the nature of the forces reveals that there is much scope for further improving the electronic force models within MD. © 2010 Materials Research Society.Accepted versio
Calcium, vitamin D and iron status of elite rugby union players during a competitive season
Sub-optimal calcium, vitamin D and iron intakes are typical in athletes. However, quantification by dietary intake may be erroneous, with biomarkers providing a more accurate assessment. This study aimed to determine the calcium, vitamin D and iron status of 8 junior (i.e., under-18 [U18]; age 15.5 ± 0.5 years; height 180.4 ± 6.7 cm; body mass 81.6 ± 14.3 kg) and 12 senior (i.e., over-18 [O18]; age 19.7 ± 1.8 years; height 184.9 ± 6.9 cm; body mass 97.4 ± 14.4 kg) male rugby union players, and assess their adequacy against reference values. Fasted serum calcium, 25(OH)D and ferritin concentrations were analysed using Enzyme-Linked Immunosorbent Assay during the in-season period (March-April). U18 had very likely greater calcium concentrations than O18 (2.40 ± 0.08 vs. 2.25 ± 0.19 mmol.l-1). Differences between U18 and O18 were unclear for 25(OH)D (20.21 ± 11.57 vs. 29.02 ± 33.69 nmol.l-1) and ferritin (59.33 ± 34.61 vs. 85.25 ± 73.53 µg.l-1). Compared to reference values, all U18 had adequate serum calcium concentrations, whereas 33% and 67% of O18 were deficient and adequate, respectively. All U18 and 83% of O18 had severely deficient, deficient or inadequate vitamin D concentrations. Adequate (8%) and optimal (8%) concentrations of vitamin D were observed in O18. All U18 and 75% of O18 had adequate ferritin concentrations. Potential toxicity (17%) and deficient (8%) ferritin concentrations were observed in O18. Vitamin D intake should be increased and multiple measures obtained throughout the season. More research is required on the variation of micronutrient statu
Bayesian optimization for materials design
We introduce Bayesian optimization, a technique developed for optimizing
time-consuming engineering simulations and for fitting machine learning models
on large datasets. Bayesian optimization guides the choice of experiments
during materials design and discovery to find good material designs in as few
experiments as possible. We focus on the case when materials designs are
parameterized by a low-dimensional vector. Bayesian optimization is built on a
statistical technique called Gaussian process regression, which allows
predicting the performance of a new design based on previously tested designs.
After providing a detailed introduction to Gaussian process regression, we
introduce two Bayesian optimization methods: expected improvement, for design
problems with noise-free evaluations; and the knowledge-gradient method, which
generalizes expected improvement and may be used in design problems with noisy
evaluations. Both methods are derived using a value-of-information analysis,
and enjoy one-step Bayes-optimality
Comparison of breast and bowel cancer screening uptake patterns in a common cohort of South Asian women in England
Background: Inequalities in uptake of cancer screening by ethnic minority populations are well documented in a
number of international studies. However, most studies to date have explored screening uptake for a single cancer
only. This paper compares breast and bowel cancer screening uptake for a cohort of South Asian women invited to
undertake both, and similarly investigates these women's breast cancer screening behaviour over a period of fifteen
years.
Methods: Screening data for rounds 1, 2 and 5 (1989-2004) of the NHS breast cancer screening programme and for
round 1 of the NHS bowel screening pilot (2000-2002) were obtained for women aged 50-69 resident in the English
bowel screening pilot site, Coventry and Warwickshire, who had been invited to undertake breast and bowel cancer
screening in the period 2000-2002. Breast and bowel cancer screening uptake levels were calculated and compared
using the chi-squared test.
Results: 72,566 women were invited to breast and bowel cancer screening after exclusions. Of these, 3,539 were South
Asian and 69,027 non-Asian; 18,730 had been invited to mammography over the previous fifteen years (rounds 1 to 5).
South Asian women were significantly less likely to undertake both breast and bowel cancer screening; 29.9% (n =
1,057) compared to 59.4% (n = 40,969) for non-Asians (p < 0.001). Women in both groups who consistently chose to
undertake breast cancer screening in rounds 1, 2 and 5 were more likely to complete round 1 bowel cancer screening.
However, the likelihood of completion of bowel cancer screening was still significantly lower for South Asians; 49.5% vs.
82.3% for non-Asians, p < 0.001. South Asian women who undertook breast cancer screening in only one round were
no more likely to complete bowel cancer screening than those who decided against breast cancer screening in all
three rounds. In contrast, similar women in the non-Asian population had an increased likelihood of completing the
new bowel cancer screening test. The likelihood of continued uptake of mammography after undertaking screening in
round 1 differed between South Asian religio-linguistic groups. Noticeably, women in the Muslim population were less
likely to continue to participate in mammography than those in other South Asian groups.
Conclusions: Culturally appropriate targeted interventions are required to reduce observed disparities in cancer
screening uptakes
Estimation of proteinuria as a predictor of complications of pre-eclampsia: a systematic review
Background
Proteinuria is one of the essential criteria for the clinical diagnosis of pre-eclampsia. Increasing levels of proteinuria is considered to be associated with adverse maternal and fetal outcomes. We aim to determine the accuracy with which the amount of proteinuria predicts maternal and fetal complications in women with pre-eclampsia by systematic quantitative review of test accuracy studies.
Methods
We conducted electronic searches in MEDLINE (1951 to 2007), EMBASE (1980 to 2007), the Cochrane Library (2007) and the MEDION database to identify relevant articles and hand-search of selected specialist journals and reference lists of articles. There were no language restrictions for any of these searches. Two reviewers independently selected those articles in which the accuracy of proteinuria estimate was evaluated to predict maternal and fetal complications of pre-eclampsia. Data were extracted on study characteristics, quality and accuracy to construct 2 × 2 tables with maternal and fetal complications as reference standards.
Results
Sixteen primary articles with a total of 6749 women met the selection criteria with levels of proteinuria estimated by urine dipstick, 24-hour urine proteinuria or urine protein:creatinine ratio as a predictor of complications of pre-eclampsia. All 10 studies predicting maternal outcomes showed that proteinuria is a poor predictor of maternal complications in women with pre-eclampsia. Seventeen studies used laboratory analysis and eight studies bedside analysis to assess the accuracy of proteinuria in predicting fetal and neonatal complications. Summary likelihood ratios of positive and negative tests for the threshold level of 5 g/24 h were 2.0 (95% CI 1.5, 2.7) and 0.53 (95% CI 0.27, 1) for stillbirths, 1.5 (95% CI 0.94, 2.4) and 0.73 (95% CI 0.39, 1.4) for neonatal deaths and 1.5 (95% 1, 2) and 0.78 (95% 0.64, 0.95) for Neonatal Intensive Care Unit admission.
Conclusion
Measure of proteinuria is a poor predictor of either maternal or fetal complications in women with pre-eclampsia
Meraculous: De Novo Genome Assembly with Short Paired-End Reads
We describe a new algorithm, meraculous, for whole genome assembly of deep paired-end short reads, and apply it to the assembly of a dataset of paired 75-bp Illumina reads derived from the 15.4 megabase genome of the haploid yeast Pichia stipitis. More than 95% of the genome is recovered, with no errors; half the assembled sequence is in contigs longer than 101 kilobases and in scaffolds longer than 269 kilobases. Incorporating fosmid ends recovers entire chromosomes. Meraculous relies on an efficient and conservative traversal of the subgraph of the k-mer (deBruijn) graph of oligonucleotides with unique high quality extensions in the dataset, avoiding an explicit error correction step as used in other short-read assemblers. A novel memory-efficient hashing scheme is introduced. The resulting contigs are ordered and oriented using paired reads separated by ∼280 bp or ∼3.2 kbp, and many gaps between contigs can be closed using paired-end placements. Practical issues with the dataset are described, and prospects for assembling larger genomes are discussed
Growth characteristics in individuals with osteogenesis imperfecta in North America: results from a multicenter study.
PurposeOsteogenesis imperfecta (OI) predisposes people to recurrent fractures, bone deformities, and short stature. There is a lack of large-scale systematic studies that have investigated growth parameters in OI.MethodsUsing data from the Linked Clinical Research Centers, we compared height, growth velocity, weight, and body mass index (BMI) in 552 individuals with OI. Height, weight, and BMI were plotted on Centers for Disease Control and Prevention normative curves.ResultsIn children, the median z-scores for height in OI types I, III, and IV were -0.66, -6.91, and -2.79, respectively. Growth velocity was diminished in OI types III and IV. The median z-score for weight in children with OI type III was -4.55. The median z-scores for BMI in children with OI types I, III, and IV were 0.10, 0.91, and 0.67, respectively. Generalized linear model analyses demonstrated that the height z-score was positively correlated with the severity of the OI subtype (P < 0.001), age, bisphosphonate use, and rodding (P < 0.05).ConclusionFrom the largest cohort of individuals with OI, we provide median values for height, weight, and BMI z-scores that can aid the evaluation of overall growth in the clinic setting. This study is an important first step in the generation of OI-specific growth curves
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