Longitudinal changing relationships between growth tempo and vertical stiffness in movement across maturation.

PURPOSE: To determine whether average growth tempo influenced longitudinal relationships between maturity status and coordination capability using a 15-s hopping task (Aim 1). To investigate how differences in absolute growth tempo were associated with change in coordination capability within and across peak growth (Aim 2). METHODS: Participants were N1 = 110 (Aim 1) and N2 = 71 (Aim 2) Australian male competitive swimmers, aged 10-15 years, exposed to repeated-measures tracking (2-years, and 12-months respectively) of maturity status, growth tempo and movement coordination capability. Coordination capability was estimated via vertical stiffness (KV) in a hopping task, reflected by participant mean KV and between-jump coefficient of variation (CV). RESULTS: For Aim 1, log-linear mixed model trends identified maturity status and growth tempo were significantly associated with KV mean and KV CV. For a given maturity status, mean KV was 9% lower in the 'High' average growth tempo group than the 'Low' average tempo group. For Aim 2, mixed repeated-measures analyses of variance identified how time points of increased growth tempo were significantly associated with 7-11% reductions in mean KV, with similar mean KV decrements irrespective of growth tempo group. Meanwhile, KVCV only illustrated progressive longitudinal reductions. CONCLUSIONS: Within maturational progression, short-term accelerations in growth tempo corresponded with short-term decreases in KV mean, suggesting temporary disruptions to movement coordination capability. Measuring growth tempo and applying hopping tasks in specific movement contexts could help consistently identify disturbances in motor coordination.

The Longitudinal Mediating Influence of Maturation on the Relationship Between Strength and Performance in Male Youth Swimmers.

PURPOSE: To examine the longitudinal relationships between shoulder internal and external rotation (IR and ER) strength, maturity status, and swim performance (aim 1). To determine whether maturity status mediated (partially/fully) the relationship between shoulder IR/ER strength and performance in age-group swimmers (aim 2). METHODS: Using a repeated-measures design, anthropometrics, maturity status, shoulder IR/ER strength, and 200-m front-crawl velocity were assessed over 3 competition seasons in N = 82 Australian male competitive swimmers (10-15 y). For aim 1, linear mixed models examined longitudinal relationships between assessed variables. For aim 2, causal mediation analyses examined proportional (in)direct contributions of maturity status between shoulder IR strength and swim performance. RESULTS: For aim 1, linear mixed models identified a significant relationship between shoulder IR strength and swim performance over time (F1,341.25 = 16.66, P < .001, marginal R2 = .13, conditional R2 = .91). However, maturity status was influential (ΔAkaike information criterion = -75.8, χ2 = 19.98, P < .001), suggesting removal of the shoulder IR strength-swim velocity relationship (F1,214.1 = 0.02, P = .88). For aim 2, mediation analyses identified maturity status as fully mediating the shoulder IR strength-swim velocity relationship (92.30%, P < .001). CONCLUSIONS: Shoulder IR and ER strength did not account for variance in longitudinal age-group swim performance independent of maturity status. Interindividual differences in maturity status fully explained the relationship between shoulder IR/ER strength and swim performance. For practitioners, findings promote the need to account for maturation status and question the rationale for upper-limb strength assessment during maturational years.

Maturation-based Corrective Adjustment Procedures (Mat-CAPs) in youth swimming: Evidence for restricted age-group application in females.

Inter-individual differences in maturation-associated development can lead to variations in physical performance, resulting in performance (dis)advantages and maturation selection bias within youth sport systems. To address such bias and account for maturational differences, Maturation-based Corrective Adjustment Procedures (Mat-CAPs) could be beneficial. The present study aimed to: (1) determine maturity timing distributions in youth female swimming; (2) quantify the relationship between maturation status and 100-m front-crawl (FC) performance; (3) implement Mat-CAPs to remove maturational influences upon swimming performance. For Aim 1 and 2, participants were 663 female (10-15 years) swimmers who participated in 100-m FC events at Australian regional, state, and national-level competitions between 2016-2020 and underwent anthropometric assessment (mass, height and sitting height) to estimate maturity timing and offset. For Aim 3, participants aged 10-13 years were categorised into maturity timing categories. Maturity timing distributions for Raw ('All', 'Top 50%' and 'Top 25%') and Correctively Adjusted swim times were examined. Chi-square, Cramer's V and Odds Ratios determined the presence of maturation biases, while Mat-CAPs identified whether such biases were removed in targeted age and selection-groups. Results identified that between 10-13 years, a significantly higher frequency of 'early' maturers was apparent, although tapered toward higher frequencies of 'Late-normative' maturers by 14-15 years. A curvilinear relationship between maturity-offset and swim performance was identified (R2 = 0.51, p<0.001) and utilised for Mat-CAPs. Following Mat-CAPs application, maturity timing biases evident in affected age-groups (10-13 years), and which were magnified at higher selection levels ('Top 50%' & '25%' of swim performances) were predominantly removed. Findings highlight how maturation advantages in females occurred until approximately 13 years old, warranting restricted Mat-CAPs application. Mat-CAPS has the potential to improve female swimmer participation experiences and evaluation.

Area level deprivation and monthly COVID-19 cases: The impact of government policy in England.

This paper aims to understand the relationship between area level deprivation and monthly COVID-19 cases in England in response to government policy throughout 2020. The response variable is monthly reported COVID-19 cases at the Middle Super Output Area (MSOA) level by Public Health England, with Index of Multiple Deprivation (IMD), ethnicity (percentage of the population across 5 ethnicity categories) and the percentage of the population older than 70 years old and time as predictors. A GEE population-averaged panel-data model was employed to model trends in monthly COVID-19 cases with the population of each MSOA included as the exposure variable. Area level deprivation is significantly associated with COVID-19 cases from March 2020; however, this relationship is reversed in December 2020. Follow up analysis found that this reversal was maintained when controlling for the novel COVID-19 variant outbreak in the South East of England. This analysis indicates that changes in the role of deprivation and monthly reported COVID-19 over time cases may be linked to two government policies: (1) the premature easing of national restrictions in July 2020 when cases were still high in the most deprived areas in England and (2) the introduction of a regional tiered system in October predominantly in the North of England. The analysis adds to the evidence showing that deprivation is a key driver of COVID-19 outcomes and highlights the unintended negative impact of government policy.

Local Government Approaches to Combating COVID-19 Inequities: A Durham County Department of Public Health Perspective.

When a novel coronavirus disease (COVID-19) made major headlines in 2020, it further exposed an existing public health crisis related to inequities within our communities and health care delivery system. Throughout the COVID-19 pandemic, populations of color had higher infection and mortality rates, and even experienced greater disease severity compared to whites. Populations of color often bear the brunt of COVID-19 and other health inequities, due to the multifaceted relationship between systemic racism and the social determinants of health. As this relationship continues to perpetuate health inequities, the local health department is an agency that has the jurisdiction and responsibility to prevent disease and protect the health of the communities they serve. When equity is integrated into a health department's operational infrastructure as a disease prevention strategy, it can elevate the agency's response to public health emergencies. Collecting, reporting, and tracking demographic data that is necessary to identify inequities becomes a priority to facilitate a more robust public health response. The purpose of this paper is to present strategies of how a local health department operationalized equity in various stages of COVID-19 response and apply these methods to future public health emergencies to better serve vulnerable communities.

Longitudinal Relationships Between Maturation, Technical Efficiency, and Performance in Age-Group Swimmers: Improving Swimmer Evaluation.

PURPOSE: The study aimed to (1) accurately examine longitudinal relationships between maturity status and both technical skill indices and performance in Australian male (N = 64) age-group Front-crawl swimmers (10-15 y) and (2) determine whether individual differences in maturation influenced relationships between technical skill level and swimming performance. METHODS: A repeated-measures design was used to assess maturity status and performance on 200-m Front-crawl trial across 2 competition seasons (2018-2020). Assessments were made on 3 to 5 occasions (median = 3) separated by approximately 4 months. Average horizontal velocity and stroke frequency were used to calculate technical skill indices, specifically stroke index, and arm propelling efficiency. Relationships between variables were assessed using linear mixed models, identifying fixed, and random effect estimates. RESULTS: Curvilinear trends best described significant longitudinal relationships between maturity status with horizontal velocity (F = 10.33 [1, 233.77]; P = .002) and stroke index (F = 5.55 [1, 217.9]; P = .02) during 200-m Front-crawl trials. Maturity status was not significantly related to arm propelling efficiency (P = .08). However, arm propelling efficiency was an independent predictor of Front-crawl velocity (F = 55.89 [1, 210.45]; P < .001). CONCLUSIONS: Maturity status predicted assessment of swimmer technical skill (stroke index) and swimming performance. However, technical skill accessed via arm propelling efficiency was independent of maturation and was predictive of performance. Maturity status influences performance evaluation based on technical skill and velocity. Findings highlight the need to account for maturation and technical skill in age-group swimmers to better inform swimmer evaluation.

Maturity-related developmental inequalities in age-group swimming: The testing of 'Mat-CAPs' for their removal.

OBJECTIVES: To (1) examine the association between maturity timing and performance-based selection levels in (N=708) Australian male 100-m Freestyle swimmers (12-17 years); (2) identify the relationship between maturation status and 100-m Freestyle performance; and (3) determine whether Maturation-based Corrective Adjustment Procedures (Mat-CAPs) could remove maturation-related differences in swimming performance. METHODS: In Part 1, maturity timing category distributions ('Early', 'Early Normative', 'Late Normative' and 'Late') for 'All', 'Top 50%' and '25%' of raw swimming times were examined within and across age-groups. In Part 2, multiple regression analyses quantified the relationship between maturity offset (YPHV) and swimming performance. In Part 3, sample-based maturity timing category distributions were examined based on raw and correctively adjusted swim times for 12-17 year old age-groups. RESULTS: Based on raw swim times, a high prevalence of 'Early-maturing' swimmers, with large effect sizes was identified (e.g., 14 years 'All' - χ2 (3, 151=111.98, p<0.001; 'Early' v 'Late' OR=82.0 95%CI=4.77, 1409.9); while a complete absence of 'Late-maturers' was apparent in the sample (N=708). When maturity categories were re-defined based on sample mean±standard deviation, and when using the expected curvilinear trendline identified in Part 2, Mat-CAPs mitigated maturity timing biases across all age-groups and selection levels, and removed the Freestyle performance advantage afforded by advanced maturity timing and status. CONCLUSIONS: Removing the influence of maturation-related developmental differences could help improve youth swimmer participation experiences and improve the accuracy of identifying genuinely skilled age-group swimmers.

Testing the application of corrective adjustment procedures for removal of relative age effects in female youth swimming.

The purpose of this study was (1) accurately estimate longitudinal relationships between decimal age (i.e., chronological and relative) and performance in Australian female 100 m (N = 765) and 200 m (N = 428) Breaststroke swimmers (10-18 years); and (2) determine whether corrective adjustment procedures could remove Relative Age Effects (RAEs) in an independent sample of age-matched 100 m (N = 2,491) and 200 m (N = 1,698) state/national level Breaststroke swimmers. In Part 1, growth curve modelling quantified longitudinal relationships between decimal age and swimming performance. In Part 2, relative age distributions (Quartile 1-4) for "All", "Top 25%" and "10%" of swimming times were examined based on raw and correctively adjusted swim times for age-groups. Based on raw swim times, finding identified RAE effect sizes increased in magnitude (small-medium) with selection level ("All"-"Top 25%") in 12-14 years age-groups for both events. However, when correctively adjusted swim performances were examined, RAEs were primarily absent across all age-groups and selection levels. Using longitudinal reference data, corrective adjustment procedures removed relative age advantages in female youth Breaststroke performance. Removing the influence of relative age-related differences is predicted to improve the accuracy of identifying genuinely skilled youth swimmers.

Removing relative age effects from youth swimming: The development and testing of corrective adjustment procedures.

OBJECTIVES: (1) Generate accurate estimates of the relationship between decimal age (i.e., chronological and relative) with swimming performance based on longitudinal data. (2) Determine whether corrective adjustment procedures can remove Relative Age Effects (RAEs) from junior/youth swimming. DESIGN: Longitudinal and repeated years of cross-sectional performance data were examined. METHODS: (1) Participants were 553 male 100m Freestyle swimmers (10-18 years) who participated in ≥five annual events between 1999-2017. Growth curve modelling quantified the relationship between age and swimming performance, permitting corrective adjustment calculations. (2) Participants were N=2141 male 100m Freestyle swimmers (13-16 years) who swam at state/national events in 2015-2017. Relative age distributions for 'All', 'Top 50%', '25%' and '10%' of swimming times were examined based on raw and correctively adjusted swim times. Chi-square, Cramer's V and Odds Ratios (OR) determined whether relative age (quartile) inequalities existed according to age-groups, selection level and correctively adjusted swim times. RESULTS: Based on raw swim times, for 'All' swimmers RAEs was evident at 13 and 14 years-old and dissipated thereafter. But, RAE effect sizes substantially increased with selection level, with large-medium effects between 13-15 years-old (e.g., 15 years - Top 50% Q1v Q4 OR=2.28; Top 10%=6.02). However, when correctively adjusted swim times were examined, RAEs were predominantly absent across age-group and selection levels. CONCLUSIONS: With accurate longitudinal reference data, corrective adjustment procedures effectively removed RAEs from 100m Freestyle swimming performance, suggesting the potential to improve swimming participation experience and performance evaluation.

Transient Relative Age Effects across annual age groups in National level Australian Swimming.

OBJECTIVES: To determine the prevalence, magnitude and transient patterning of Relative Age Effects (RAEs) according to sex and stroke event across all age-groups at the Australian National age swimming Championships. DESIGN: Repeated years of cross-sectional participation data were examined. METHODS: Participants were 6014 unique male (3185) and female (2829) swimmers (aged 12-18 years) who participated in Freestyle (50, 400m) and/or Breaststroke (100, 200m) at the National age swimming Championships between 2000-2014 (inclusive). RAE prevalence, magnitude and transience were determined using Chi-square tests and Cramer's V estimates for effect size. Odds Ratios (OR) and 95% Confidence Intervals (CI) examined relative age quartile discrepancies. These steps were applied across age-groups and according to sex and each stroke event. RESULTS: Consistent RAEs with large-medium effect sizes were evident for males at 12-15 years of age respectively, and with large-medium effects for females at 12-14 respectively across all four swimming strokes. RAE magnitude then consistently reduced with age across strokes (e.g., Q1 vs. Q4 OR range 16year old males=0.94-1.20; females=0.68-1.41). With few exceptions, by 15-16 years RAEs had typically dissipated; and by 17-18 years, descriptive and significant inverse RAEs emerged, reflecting overrepresentation of relatively younger swimmers. CONCLUSIONS: Performance advantages associated with relative age (and thereby likely growth and maturation) are transient. Greater consideration of transient performance and participation in athlete development systems is necessary. This may include revising the emphasis of sport programmes according to developmental stages and delaying forms of athlete selection to improve validity.

A comparison of statistical emulation methodologies for multi-wave calibration of environmental models.

Expensive computer codes, particularly those used for simulating environmental or geological processes, such as climate models, require calibration (sometimes called tuning). When calibrating expensive simulators using uncertainty quantification methods, it is usually necessary to use a statistical model called an emulator in place of the computer code when running the calibration algorithm. Though emulators based on Gaussian processes are typically many orders of magnitude faster to evaluate than the simulator they mimic, many applications have sought to speed up the computations by using regression-only emulators within the calculations instead, arguing that the extra sophistication brought using the Gaussian process is not worth the extra computational power. This was the case for the analysis that produced the UK climate projections in 2009. In this paper, we compare the effectiveness of both emulation approaches upon a multi-wave calibration framework that is becoming popular in the climate modeling community called "history matching." We find that Gaussian processes offer significant benefits to the reduction of parametric uncertainty over regression-only approaches. We find that in a multi-wave experiment, a combination of regression-only emulators initially, followed by Gaussian process emulators for refocussing experiments can be nearly as effective as using Gaussian processes throughout for a fraction of the computational cost. We also discover a number of design and emulator-dependent features of the multi-wave history matching approach that can cause apparent, yet premature, convergence of our estimates of parametric uncertainty. We compare these approaches to calibration in idealized examples and apply it to a well-known geological reservoir model.

Molecular determinants of the prothrombogenic phenotype assumed by inflamed colonic venules.

Although platelets have been implicated in the pathogenesis of human inflammatory bowel diseases, little is known about the magnitude of platelet accumulation in the inflamed bowel, what regulates this process, and its relevance to the overall inflammatory response. In this study, intravital video microscopy was used to monitor the trafficking of platelets and leukocytes and vascular permeability in colonic venules during the development of colonic inflammation induced by 3% dextran sodium sulfate (DSS). Blocking antibodies directed against different adhesion molecules as well as P-selectin-deficient mice were used to define the adhesive determinants of DSS-induced platelet recruitment. DSS induced an accumulation of adherent platelets that was temporally correlated with the appearance of adherent leukocytes and with disease severity. Platelet adhesion and, to a lesser extent, leukocyte adhesion were attenuated by immunoblockade of P-selectin and its ligand P-selectin glycoprotein ligand-1 (PSGL-1), with contributions from both platelet- and endothelial cell-associated P-selectin. DSS induced a rapid and sustained increase in vascular permeability that was greatly attenuated in P-selectin-deficient mice. P-selectin bone marrow chimeras revealed that both endothelial cell- and platelet-associated P-selectin contribute to the P-selectin expression detected in the inflamed colonic microvasculature, with endothelial P-selectin making a larger contribution. Our findings indicate that colonic inflammation is associated with the induction of a prothrombogenic phenotype in the colonic microcirculation, with P-selectin and its ligand PSGL-1 playing a major role in the recruitment of platelets.

Contributions of LFA-1 and Mac-1 to brain injury and microvascular dysfunction induced by transient middle cerebral artery occlusion.

Although the beta2-integrins have been implicated in the pathogenesis of cerebral ischemia-reperfusion (I/R) injury, the relative contributions of the alpha-subunits to the pathogenesis of ischemic stroke remains unclear. The objective of this study was to determine whether and how genetic deficiency of either lymphocyte function-associated antigen-1 (LFA-1) or macrophage-1 (Mac-1) alters the blood cell-endothelial cell interactions, tissue injury, and organ dysfunction in the mouse brain exposed to focal I/R. Middle cerebral artery occlusion was induced for 1 h (followed by either 4 or 24 h of reperfusion) in wild-type mice and in mice with null mutations for either LFA-1 or Mac-1. Neurological deficit and infarct volume were monitored for 24 h after reperfusion. Platelet- and leukocyte-vessel wall adhesive interactions were monitored in cortical venules by intravital microscopy. Mice with null mutations for LFA-1 or Mac-1 exhibited significant reductions in infarct volume. This was associated with a significant improvement in the I/R-induced neurological deficit. Leukocyte adhesion in cerebral venules did not differ between wild-type and mutant mice at 4 h after reperfusion. However, after 24 h of reperfusion, leukocyte adhesion was reduced in both LFA-1- and Mac-1-deficient mice compared with their wild-type counterparts. Platelet adhesion was also reduced at both 4 and 24 h after reperfusion in the LFA-1- and Mac-1-deficient mice. These findings indicate that both alpha-subunits of the beta2-integrins contribute to the brain injury and blood cell-vessel wall interactions that are associated with transient focal cerebral ischemia.

Molecular determinants of the prothrombogenic and inflammatory phenotype assumed by the postischemic cerebral microcirculation.

BACKGROUND AND PURPOSE: Circulating blood cells have been implicated in the pathogenesis of cerebral ischemia/reperfusion (I/R) injury and stroke. The objective of this study was to define the magnitude and molecular determinants of the platelet- and leukocyte-endothelial cell adhesive interactions induced by I/R in the mouse brain. METHODS: Bilateral common carotid artery occlusion was induced for 1 hour in C57BL/6 mice, followed by either 40 minutes or 4 hours of reperfusion. Fluorescent platelets were administered intravenously, and the frontal brain surface was observed with intravital fluorescence microscopy. Leukocyte-endothelial cell adhesion was monitored with the use of rhodamine-6G. RESULTS: Ischemia followed by 40 minutes of reperfusion resulted in the rolling (125.1+/-23.6/mm2) and firm adhesion (109.5+/-25.8/mm2) of leukocytes but not platelets in venules. However, with 4 hours of reperfusion, rolling (138.8+/-24.6/mm2) and firm adhesion (153.7+/-22.3/mm2) of platelets were detected, and this was accompanied by a more intense recruitment of rolling (374.5+/-54.6/mm2) and adherent (445.2+/-57.1/mm2) leukocytes. In mice deficient in either P-selectin (P-selectin-/-) or intercellular adhesion molecule-1 (ICAM-1) (ICAM-1-/-), the I/R-induced platelet-endothelial cell (by 80% and 60%, respectively) and leukocyte-endothelial cell (by 84% and 78%, respectively) interactions were significantly blunted compared with those of wild-type mice. CONCLUSIONS: These findings indicate that I/R promotes the adhesion of both platelets and leukocytes in cerebral venules, with the accumulation of adherent leukocytes preceding the recruitment of platelets. Both P-selectin and ICAM-1 contribute to the inflammatory and prothrombogenic state induced by cerebral I/R.

TOWNES-BROCKS SYNDROME: REPORT OF THREE ADDITIONAL PATIENTS WITH PREVIOUSLY UNDESCRIBED RENAL AND CARDIAC ABNORMALITIES.

Cardiac and renal abnormalities have been reported infrequently in Townes-Brocks syndrome. This paper presents three new patients with this syndrome; previously undescribed cardiac and renal abnormalities consisting of truncus arteriosus, ventricular septal defect, unilateral renal agenesis, and renal dysplasia are presented. The spectrum of findings in this syndrome should include cardiac and renal abnormalities.