Effect of propellant morphology on the acoustics of the BATES motor

This study shows the results of three-dimensional simulations of the chamber flow within the BATES (Ballistic Test and Evaluation System) 15 pound motor. The injection boundary conditions for the motor are defined by the velocity-temperature temporal correlations. Three different propellant morphologies are modeled and tested along with a random white noise model that represents the current surrogate for propellant modeling. The data gained from each of these simulations is compared using contour plots of the chamber flow characteristics and by performing FFT analysis on the head-end pressure histories. The study is then expanded to include analysis of the 70 pound version of the BATES motor. The analysis of one of the propellant morphologies used in the study of the smaller motor and the white noise surrogate confirm the results of the 15 pound motor. Analysis of the acoustics and the characteristics of the chamber flow correspond with what was previously found. The results from these comparisons show that propellant morphology has a significant effect on the internal chamber flow dynamics

Does the Brief Self-Control Scale Assess Relatively Stable Individual Differences in Self-Control Among Endurance Athletes?

Endurance athletes are a population where self-control in the form of following training plans, race plans, and pacing schedules is key to performing successfully. A valid and stable measure of self-control has theoretical and applied value through the ability to identify athletes who might be susceptible to poor self-control. The present study reports the test-retest stability of the Brief Self-Control Scale (BSCS). 132 endurance athletes (18-65 years) completed the 13-item BSCS on two occasions, separated by two weeks. Stability was measured by calculating the test-retest differences for each questionnaire item, with a stable item showing 90% of respondents’ test-retest differences within a reference value of ±1. Analyses revealed seven items to be stable with the question, Q11 = “I am able to work effectively toward long-term goals”, demonstrating greatest stability (96.3%). In contrast, six items showed relatively poor stability with test-retest difference scores ranging from 83.4-89.4%. Chi-square tests of independence revealed no associations with categorical levels of age, gender, sport, and training habits. In the context of the current findings, we argue that the six unstable items do not represent dispositional self-control behaviours among endurance athletes. Future researchers are encouraged to assess the stability of individual items rather than favoring a summary statistic, particularly when developing trait measures

Long-term quality of life postacute kidney injury in cardiac surgery patients.

Acute renal failure after cardiac surgery is known to be associated with significant short-term morbidity and mortality. There have as yet been no major reports on long-term quality of life (QOL). This study assessed the impact of acute kidney injury (AKI) and renal replacement therapy (RRT) on long-term survival and QOL after cardiac surgery. The need for long-term RRT is also assessed

Test-retest stability of the Task and Ego Orientation Questionnaire.

Establishing stability, defined as observing minimal measurement error in a test-retest assessment, is vital to validating psychometric tools. Correlational methods, such as Pearson product-moment, intraclass, and kappa are tests of association or consistency, whereas stability or reproducibility (regarded here as synonymous) assesses the agreement between test-retest scores. Indexes of reproducibility using the Task and Ego Orientation in Sport Questionnaire (TEOSQ; Duda & Nicholls, 1992) were investigated using correlational (Pearson product-moment, intraclass, and kappa) methods, repeated measures multivariate analysis of variance, and calculating the proportion of agreement within a referent value of +/-1 as suggested by Nevill, Lane, Kilgour, Bowes, and Whyte (2001). Two hundred thirteen soccer players completed the TEOSQ on two occasions, 1 week apart. Correlation analyses indicated a stronger test-retest correlation for the Ego subscale than the Task subscale. Multivariate analysis of variance indicated stability for ego items but with significant increases in four task items. The proportion of test-retest agreement scores indicated that all ego items reported relatively poor stability statistics with test-retest scores within a range of +/-1, ranging from 82.7-86.9%. By contrast, all task items showed test-retest difference scores ranging from 92.5-99%, although further analysis indicated that four task subscale items increased significantly. Findings illustrated that correlational methods (Pearson product-moment, intraclass, and kappa) are influenced by the range in scores, and calculating the proportion of agreement of test-retest differences with a referent value of +/-1 could provide additional insight into the stability of the questionnaire. It is suggested that the item-by-item proportion of agreement method proposed by Nevill et al. (2001) should be used to supplement existing methods and could be especially helpful in identifying rogue items in the initial stages of psychometric questionnaire validation

Motor coordination among Greek children : from assessment to intervention

Background: Developmental Coordination Disorder (DCD) describes children with a difficulty to acquire age-specific motor skills. Although there is a significant body of literature addressing developmental and cognitive issues in children with DCD, few studies have actually examined the associations between DCD, physical activity and physical fitness. Therefore, the aim of the present research work was to assess these associations in a series of four successive studies which were set: a) (study 1) to estimate DCD prevalence rates in Greek children and investigate whether these children exhibit different obesity and cardiorespiratory fitness levels than an overseas sample, b) (study 2) to provide evidence on the association between DCD and physical fitness levels, c) (study 3) examine whether a motor skills and exercise training intervention programme affects motor proficiency in a cohort of elementary school children with and without DCD, and d) (study 4) to test the hypothesis that DCD is associated with CVD risk, identify modes of physical activity that mediate such an association and to evaluate the CSAPPA scale as a potential tool for identifying Greek children for DCD. Methods: The total of 574 Greek (Age: 11.46 ± 1.54 years; BMI: 19.96 ± 3.53) children were assessed for anthropometry, physical fitness (flexibility, hand strength, leg explosive power, speed and cardiorespiratory fitness), motor competence (i.e., short form of the Bruininks-Oseretsky Test of Motor Profiency- BOTMP-sf) and subjected to two self assessments for: i) perception of adequacy for physical activity (CSAPPA scale), and ii) children’s participation in physical activity (Participation Questionnaire - PQ). Results: Study 1: Greek children demonstrated significantly higher DCD prevalence rates (p<0.05), higher body fat (p<0.05) and were inferior in both cardiorespiratory fitness (p<0.05) and motor competence (p<0.05) compared to an overseas sample. Study 2: Greek children with DCD demonstrated significantly higher BMI values (p<0.01) and lower leg explosive power (p<0.01), speed (p<0.01) and hand strength (p<0.01) than those without DCD. Study 3: Results showed a significant main effect of time [F(14, 115) = 3.79, p< 0.001; η2 = 0.32] for motor competence (p<0.001) between children with and without DCD. Significant main effects of group (i.e intervention and control groups) [F(42, 351) = 4.01, p< 0.001; η2 = 0.33] were observed for BMI (p<0.01), motor competence (p<0.01), cardiorespiratory fitness (p<0.01), hand strength (p<0.05), leg explosive power (p<0.05), speed (p<0.01), and free time play activities (p<0.05). Study 4: Chi-square comparisons and ANOVA, revealed significantly increased body mass (p<0.05), BMI (p<0.05) and inactivity (p<0.05), as well as significantly decreased cardiorespiratory fitness (p<0.05), motor competence (p<0.05), CSAPPA indices, and participation in free play (p<0.05) in children with DCD. Furthermore, BMI and cardiorespiratory fitness were significantly associated with motor competence (p<0.05) with inactivity as the mediating factor (p<0.05). ROC curve analyses for CSAPPA indicated an optimal cut-off at 62 points. Conclusions: 1) the relatively high DCD and obesity prevalence rates together with the low cardiorespiratory fitness suggest greater health risk for Greek children with the studied condition, 2) children with DCD tend to perform worse in selected physical fitness parameters compared to their normal peers, 3) motor skills and exercise training interventions for children with DCD may improve health and skills related fitness, and 4) inactivity mediates the relationship between DCD and CVD risk in children with DCD. Finally, the CSAPPA scale may serve as a practical and a cost-effective proxy assessment for identifying Greek children with DCD, however as this is not a standardised test for use with children, its use should be treated with caution until further validation work.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Acute effects of Vitamin D3 supplementation on muscle strength in Judoka athletes: a randomized placebo-controlled, double-blind trial

Objective: Indoor athletes have been shown to be prone to vitamin D3 deficiency. The aim of the study was to examine the acute effects of vitamin D supplementation on muscle function using isokinetic dynamometry. Design: Randomized placebo-controlled, double-blind study. Setting: Institutional. Participants: Adult male white national level judoka athletes (n = 22) who were involved in full-time training. Exclusion criteria were vitamin supplementation, overseas travel to sunny climes, and/or an injury incurred during the last 3 months before testing. Interventions: Subjects were randomly allocated to the treatment (150 000IU vitamin D3) or placebo and given blinded supplements by an independent researcher. Participants were tested twice, 8 days apart, on a Monday morning before the start of judo training and after 2 days of rest. A 5 to 7 mL of blood sample was collected followed by isokinetic concentric quadriceps and hamstring muscle function assessments on the right leg at 30 and 200°·s. Main outcome measures: Repeated-measures analysis of variance was used to analyze isokinetic muscle force and serum 25(OH)D3. Regression to the mean was used to examine changes in 25(OH)D3 levels over the study period. Results: The treatment group demonstrated a significant increase in serum 25(OH)D levels (34%, P ≤ 0.001) and muscle strength (13%, P = 0.01) between days 1 and 8. No significant differences were found for the placebo group for the same period. Conclusions: A single bolus of 150 000IU vitamin D3 had a significant positive effect on serum 25(OH)D levels and muscle function in vitamin D insufficient elite indoor athletes. Clinical relevance: Serum 25(OH)D3 levels of indoor athletes should be monitored throughout the year and especially during winter months. Beneficial responses, in muscle strength and serum 25(OH)D3, to 1 dose of vitamin D3 supplementation can be observed within 1 week of ingestion. Muscle strength is linked to serum 25(OH)D levels. Acute Effects of Vitamin D3 Supplementation on Muscle Strength in Judoka Athletes: A Randomized Placebo-Controlled, Double-Blind Trial (PDF Download Available). Available from: https://www.researchgate.net/publication/283499805_Acute_Effects_of_Vitamin_D3_Supplementation_on_Muscle_Strength_in_Judoka_Athletes_A_Randomized_Placebo-Controlled_Double-Blind_Trial [accessed May 10, 2016]

Can we trust “Magnitude-based inference”?

Editoria

Evidence that Differences in Fructosamine-3-Kinase Activity May be Associated with the Glycation Gap in Human Diabetes

The phenomenon of a discrepancy between glycated haemoglobin levels and other indicators of average glycaemia may be due to many factors but can be measured as the glycation gap (GGap). This GGap is associated with differences in complications in patients with diabetes and may possibly be explained by dissimilarities in deglycation in turn leading to altered production of Advanced Glycation End (AGE) products. We hypothesised that variations in the level of the deglycating enzyme Fructosamine-3-kinase (FN3K) might be associated with the GGap. We measured erythrocyte FN3K concentrations and enzyme activity in a population dichotomised for a large positive or negative GGap. FN3K protein was higher and we found a striking 3-fold greater activity (323%) at any given FN3K protein level in the erythrocytes of the negative compared with positive GGap groups. This was associated with lower AGE levels in the negative GGap group (79%), lower pro-inflammatory adipokines (Leptin/Adiponectin ratio) (73%) and much lower pro-thrombotic PAI-1 levels (19%). We conclude that FN3K may play a key role in the GGap and thus diabetes complications such that FN3K may be potential predictor of the risk of diabetes complications. Pharmacological modifications of its activity may provide a novel approach to their prevention

Advancing DNA barcoding and metabarcoding applications for plants requires systematic analysis of herbarium collections-an Australian perspective

Building DNA barcode databases for plants has historically been ad hoc, and often with a relatively narrow taxonomic focus. To realize the full potential of DNA barcoding for plants, and particularly its application to metabarcoding for mixed-species environmental samples, systematic sequencing of reference collections is required using an augmented set of DNA barcode loci, applied according to agreed data generation and analysis standards. The largest and most complete reference collections of plants are held in herbaria. Australia has a globally significant flora that is well sampled and expertly curated by its herbaria, coordinated through the Council of Heads of Australasian Herbaria. There exists a tremendous opportunity to provide a comprehensive and taxonomically robust reference database for plant DNA barcoding applications by undertaking coordinated and systematic sequencing of the entire flora of Australia utilizing existing herbarium material. In this paper, we review the development of DNA barcoding and metabarcoding and consider the requirements for a robust and comprehensive system. We analyzed the current availability of DNA barcode reference data for Australian plants, recommend priority taxa for database inclusion, and highlight future applications of a comprehensive metabarcoding system. We urge that large-scale and coordinated analysis of herbarium collections be undertaken to realize the promise of DNA barcoding and metabarcoding, and propose that the generation and curation of reference data should become a national investment priority

A grammar-based distance metric enables fast and accurate clustering of large sets of 16S sequences

Background: We propose a sequence clustering algorithm and compare the partition quality and execution time of the proposed algorithm with those of a popular existing algorithm. The proposed clustering algorithm uses a grammar-based distance metric to determine partitioning for a set of biological sequences. The algorithm performs clustering in which new sequences are compared with cluster-representative sequences to determine membership. If comparison fails to identify a suitable cluster, a new cluster is created. Results: The performance of the proposed algorithm is validated via comparison to the popular DNA/RNA sequence clustering approach, CD-HIT-EST, and to the recently developed algorithm, UCLUST, using two different sets of 16S rDNA sequences from 2,255 genera. The proposed algorithm maintains a comparable CPU execution time with that of CD-HIT-EST which is much slower than UCLUST, and has successfully generated clusters with higher statistical accuracy than both CD-HIT-EST and UCLUST. The validation results are especially striking for large datasets. Conclusions: We introduce a fast and accurate clustering algorithm that relies on a grammar-based sequence distance. Its statistical clustering quality is validated by clustering large datasets containing 16S rDNA sequences