FEEDBACK ON ROWERS’ MECHANICAL POWER OUTPUT IMPROVES COMPLIANCE TO INTENDED ON-WATER TRAINING INTENSITY

In rowing, mechanical power output (MPO) is a defining characteristic of training intensity and may be used to control on-water training intensity. However, rowers’ behavioural response to real-time feedback on MPO need to be examined first. The aim of this study was to test whether rowers are able to comply with MPO targets when they receive realtime feedback on MPO. Eighteen rowers performed training sessions in which they rowed at different intensities while receiving traditional feedback or additional real-time feedback on MPO. Rowers reduced the difference between target MPO and delivered MPO during all intensity intervals, while between-strokes fluctuations in MPO were only diminished during the medium-high intensity intervals when real-time feedback on MPO was provided. We conclude that rowers adjust their behaviour based on real-time feedback on MPO. Therefore, it has the potential to improve control of training intensity in on-water rowing

Early Dark Energy Cosmologies

We propose a novel parameterization of the dark energy density. It is particularly well suited to describe a non-negligible contribution of dark energy at early times and contains only three parameters, which are all physically meaningful: the fractional dark energy density today, the equation of state today and the fractional dark energy density at early times. As we parameterize Omega_d(a) directly instead of the equation of state, we can give analytic expressions for the Hubble parameter, the conformal horizon today and at last scattering, the sound horizon at last scattering, the acoustic scale as well as the luminosity distance. For an equation of state today w_0 < -1, our model crosses the cosmological constant boundary. We perform numerical studies to constrain the parameters of our model by using Cosmic Microwave Background, Large Scale Structure and Supernovae Ia data. At 95% confidence, we find that the fractional dark energy density at early times Omega_early < 0.06. This bound tightens considerably to Omega_early < 0.04 when the latest Boomerang data is included. We find that both the gold sample of Riess et. al. and the SNLS data by Astier et. al. when combined with CMB and LSS data mildly prefer w_0 < -1, but are well compatible with a cosmological constant.Comment: 6 pages, 3 figures; references added, matches published versio

Averaging Robertson-Walker Cosmologies

The cosmological backreaction arises when one directly averages the Einstein equations to recover an effective Robertson-Walker cosmology, rather than assuming a background a priori. While usually discussed in the context of dark energy, strictly speaking any cosmological model should be recovered from such a procedure. We apply the Buchert averaging formalism to linear Robertson-Walker universes containing matter, radiation and dark energy and evaluate numerically the discrepancies between the assumed and the averaged behaviour, finding the largest deviations for an Einstein-de Sitter universe, increasing rapidly with Hubble rate to a 0.01% effect for h=0.701. For the LCDM concordance model, the backreaction is of the order of Omega_eff~4x10^-6, with those for dark energy models being within a factor of two or three. The impacts at recombination are of the order of 10^-8 and those in deep radiation domination asymptote to a constant value. While the effective equations of state of the backreactions in Einstein-de Sitter, concordance and quintessence models are generally dust-like, a backreaction with an equation of state w_eff<-1/3 can be found for strongly phantom models.Comment: 18 pages, 11 figures, ReVTeX. Updated to version accepted by JCA

Intra-observer and interobserver variability of biventricular function, volumes and mass in patients with congenital heart disease measured by CMR imaging

Cardiovascular magnetic resonance (CMR) imaging provides highly accurate measurements of biventricular volumes and mass and is frequently used in the follow-up of patients with acquired and congenital heart disease (CHD). Data on reproducibility are limited in patients with CHD, while measurements should be reproducible, since CMR imaging has a main contribution to decision making and timing of (re)interventions. The aim of this study was to assess intra-observer and interobserver variability of biventricular function, volumes and mass in a heterogeneous group of patients with CHD using CMR imaging. Thirty-five patients with CHD (7–62 years) were included in this study. A short axis set was acquired using a steady-state free precession pulse sequence. Intra-observer and interobserver variability was assessed for left ventricular (LV) and right ventricular (RV) volumes, function and mass by calculating the coefficient of variability. Intra-observer variability was between 2.9 and 6.8% and interobserver variability was between 3.9 and 10.2%. Overall, variations were smallest for biventricular end-diastolic volume and highest for biventricular end-systolic volume. Intra-observer and interobserver variability of biventricular parameters assessed by CMR imaging is good for a heterogeneous group of patients with CHD. CMR imaging is an accurate and reproducible method and should allow adequate assessment of changes in ventricular size and global ventricular function

Multicentre reference values for cardiac magnetic resonance imaging derived ventricular size and function for children aged 0-18 years

AIMS: Cardiovascular magnetic resonance (CMR) imaging is an important tool in the assessment of paediatric cardiac disease. Reported reference values of ventricular volumes and masses in the paediatric population are based on small cohorts and several methodologic differences between studies exist. We sought to create steady-state free precession (SSFP) CMR reference values for biventricular volumes and mass by combining data of previously published studies and re-analysing these data in a standardized manner. METHODS AND RESULTS: A total of 141 healthy children (68 boys) from three European centres underwent cine-SSFP CMR imaging. Cardiac structures were manually contoured for end-diastolic and end-systolic phases in the short-axis orientation according to current standardized CMR post-processing guidelines. Volumes and masses were derived from these contours. Age-related reference curves were constructed using the lambda mu sigma method. Median age was 12.7 years (range 0.6-18.5). We report biventricular volumes and masses, unindexed and indexed for body surface area, stratified by age groups. In general, boys had approximately 15% higher biventricular volumes and masses compared with girls. Only in children aged <6 years old no gender differences could be observed. Left ventricle ejection fraction was slightly higher in boys in this study population (median 67% vs. 65%, P = 0.016). Age-related reference curves showed non-linear relations between age and cardiac parameters. CONCLUSION: We report volumetric SSFP CMR imaging reference values for children aged 0-18 years old in a relatively large multi-centre cohort. These references can be used in the follow-up of paedi

Cosmological Backreaction from Perturbations

We reformulate the averaged Einstein equations in a form suitable for use with Newtonian gauge linear perturbation theory and track the size of the modifications to standard Robertson-Walker evolution on the largest scales as a function of redshift for both Einstein de-Sitter and Lambda CDM cosmologies. In both cases the effective energy density arising from linear perturbations is of the order of 10^-5 the matter density, as would be expected, with an effective equation of state w ~ -1/19. Employing a modified Halofit code to extend our results to quasilinear scales, we find that, while larger, the deviations from Robertson-Walker behaviour remain of the order of 10^-5.Comment: 15 pages, 8 figures; replaced by version accepted by JCA

Usability, acceptability, and feasibility of the World Health Organization Labour Care Guide: A mixed-methods, multicountry evaluation.

Introduction The World Health Organization’s (WHO) Labour Care Guide (LCG) is a “next-generation” partograph based on WHO’s latest intrapartum care recommendations. It aims to optimize clinical care provided to women and their experience of care. We evaluated the LCG’s usability, feasibility, and acceptability among maternity care practitioners in clinical settings. Methods Mixed-methods evaluation with doctors, midwives, and nurses in 12 health facilities across Argentina, India, Kenya, Malawi, Nigeria, and Tanzania. Purposively sampled and trained practitioners applied the LCG in low-risk women during labor and rated experiences, satisfaction, and usability. Practitioners were invited to focus group discussions (FGDs) to share experiences and perceptions of the LCG, which were subjected to framework analysis. Results One hundred and thirty-six practitioners applied the LCG in managing labor and birth of 1,226 low-risk women. The majority of women had a spontaneous vaginal birth (91.6%); two cases of intrapartum stillbirths (1.63 per 1000 births) occurred. Practitioner satisfaction with the LCG was high, and median usability score was 67.5%. Practitioners described the LCG as supporting precise and meticulous monitoring during labor, encouraging critical thinking in labor management, and improving the provision of woman-centered care. Conclusions The LCG is feasible and acceptable to use across different clinical settings and can promote woman-centered care, though some design improvements would benefit usability. Implementing the LCG needs to be accompanied by training and supportive supervision, and strategies to promote an enabling environment (including updated policies on supportive care interventions, and ensuring essential equipment is available)

Identification of patients at risk of sudden cardiac death in congenital heart disease:The PRospEctiVE study on implaNTable cardlOverter defibrillator therapy and suddeN cardiac death in Adults with Congenital Heart Disease (PREVENTION-ACHD)

BACKGROUND Sudden cardiac death (SCD) is the main preventable cause of death in patients with adult congenital heart disease (ACHD). Since robust risk stratification methods are lacking, we developed a risk score model to predict SCD in patients with ACHD: the PRospEctiVE study on implaNTable cardlOverter defibrillator therapy and suddeN cardiac death in Adults with Congenital Heart Disease (PREVENTION-ACHD) risk score model. OBJECTIVE The purpose of this study was to prospectively study predicted SCD risk using the PREVENTION-ACHD risk score model and actual SCD and sustained ventricular tachycardia/ventricular fibrillation (VT/VF) rates in patients with ACHD. METHODS The PREVENTION-ACHD risk score model assigns 1 point each to coronary artery disease, New York Heart Association class II/III heart failure, supraventricular tachycardia, systemic ejection fraction = 120 ms, and QT dispersion >= 70 ms. SCD risk was calculated for each patient. An annual predicted risk of >= 3% constituted high risk. The primary outcome was SCD or VT/VF after 2 years. The secondary outcome was SCD. RESULTS The study included 783 consecutive patients with ACHD (n=239 (31%) left-sided lesions; n=138 (18%) tetralogy of Fallot; n=108 (14%) dosed atrial septal defect; median age 36 years; interquartile range 28-47 years; n=401 (51%) men). The PREVENTION-ACHD risk score modelidentified 58 high-risk patients. Eight patients (4 at high risk) experienced the primary outcome. The Kaplan-Meier estimates were 7% (95% confidence interval [CI] 0.1%-13.3%) in the high-risk group and 0.6% (95% CI 0.0%-1.1%) in the low-risk group (hazard ratio 12.5; 95% CI 3.1-50.9; P < .001). The risk score model's sensitivity was 0.5 and specificity 93, resulting in a C-statistic of 0.75 (95% CI 0.57-0.90). The hazard ratio for SCD was 12.4 (95% CI 1.8-88.1) (P = .01); the sensitivity and specificity were 0.5 and 0.92, and the C-statistic was 0.81 (95% CI 0.67-0.95). CONCLUSION The PREVENTION-ACHD risk score model provides greater accuracy in SCD or VT/VF risk stratification as compared with current guideline indications and identifies patients with ACHD who may benefit from preventive implantable cardioverterdefibrillator implantation

The rs1990760 polymorphism within the IFIH1 locus is not associated with Graves' disease, Hashimoto's thyroiditis and Addison's disease

Background: Three genes have been confirmed as major joint susceptibility genes for endocrine autoimmune disease:human leukocyte antigen class II, cytotoxic T-lymphocyte antigen 4 and protein tyrosine phosphatase non-receptor type 22. Recent studies showed that a genetic variation within the interferon induced helicase domain 1 (IFIH1) locus (rs1990760 polymorphism) is an additional risk factor in type 1 diabetes and Graves' disease (GD). Methods: The aim of the present study was to investigate the role of the rs1990760 polymorphism within the IFIH1 gene in German patients with GD (n=258), Hashimoto's thyroiditis (HT,n=106), Addison's disease (AD,n=195) and healthy controls (HC,n=227) as well as in 55 GD families (165 individuals, German) and 100 HT families (300 individuals, Italian). Furthermore, the interaction between rs1990760 polymorphism with human leukocyte antigen (HLA) risk haplotype DQ2(DQA*0501-DQB*0201), the risk haplotypes DQ2/DQ8 (DQA*0301-DQB*0302) and the status of thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb) and TSH receptor antibody (TRAb) in patients and families were analysed. Results:No significant differences were found between the allele and genotype frequencies for rs1990760 IFIH1 polymorphism in patients with GD, HT, AD and HC. Also no differences were observed when stratifying the IFIH1 rs1990760 polymorphism for gender, presence or absence of thyroid antibodies (GD:TRAb and HT:TPOAb/TgAb) and HLA risk haplotypes (DQ2:for GD and HT, DQ2/DQ8:for AD). Furthermore the transmission analysis in GD and HT families revealed no differences in alleles transmission for rs1990760 IFIH1 from parents with or without HLA risk haplotype DQ2 to the affected offspring. In contrast, by dividing the HT parents according to the presence or absence of thyroid Ab titers, mothers and fathers both positive for TPOAb/TgAb overtransmitted the allele A of IFIH1 rs1990760 to their HT affected offspring (61.8% vs 38.2%;p=0.05;corrected p [pc]=0.1). However, these associations did not remain statistically significant after correction of the p-values. Conclusion: In conclusion, our data suggest, no contribution from IFIH1 rs1990760 polymorphism to the pathogenesis of either Graves' disease, Hashimoto's thyroiditis or Addison's disease in our study populations. However, in order to exclude a possible influence of the studied polymorphism in specified subgroups within patients with autoimmune thyroid disease, further investigations in larger populations are needed