A Mock Data and Science Challenge for Detecting an Astrophysical Stochastic Gravitational-Wave Background with Advanced LIGO and Advanced Virgo

The purpose of this mock data and science challenge is to prepare the data analysis and science interpretation for the second generation of gravitational-wave experiments Advanced LIGO-Virgo in the search for a stochastic gravitational-wave background signal of astrophysical origin. Here we present a series of signal and data challenges, with increasing complexity, whose aim is to test the ability of current data analysis pipelines at detecting an astrophysically produced gravitational-wave background, test parameter estimation methods and interpret the results. We introduce the production of these mock data sets that includes a realistic observing scenario data set where we account for different sensitivities of the advanced detectors as they are continuously upgraded toward their design sensitivity. After analysing these with the standard isotropic cross-correlation pipeline we find that we are able to recover the injected gravitational-wave background energy density to within $2\sigma$ for all of the data sets and present the results from the parameter estimation. The results from this mock data and science challenge show that advanced LIGO and Virgo will be ready and able to make a detection of an astrophysical gravitational-wave background within a few years of operations of the advanced detectors, given a high enough rate of compact binary coalescing events

“Sharpening Your Mind, Strengthening Your Body” Parental Perceptions on the Use of Strength and Conditioning in Children and Youth

Although strength and conditioning is beneficial and safe for children to engage in there remain myths and misconceptions form parents regarding its use which prevent its widespread take up. This study explored parents’ attitudes and beliefs about strength and conditioning in their children. Thirty-one parents (21 dads, 10 mums) took part in one of four focus groups exploring the topic. Thematic analysis was used resulting in themes and sub themes centred on: Beliefs; Determinants; Coach Education; Coach Communication; and Relationship to the Game. There were also smaller aspects of the focus groups which touched upon autonomy as a concept related to implementation of strength and conditioning specifically. Overall, parents of children who play grassroots sport hold generally positive perceptions on use of strength and conditioning with their children, considering it beneficial for both physical and mental development. Key factors relating to successful implementation of strength and conditioning for children focus on having a qualified coach in that particular area (rather than a generic sports coach), effective communication between coach and parents, and coach and children in terms of the benefits of engaging with strength and conditioning

Modelling outburst floods from moraine-dammed glacial lakes

In response to climatic change, the size and number of moraine-dammed supraglacial and proglacial lake systems have increased dramatically in recent decades. Given an appropriate trigger, the natural moraine dams that impound these proglacial lakes are breached, producing catastrophic Glacial Lake Outburst Floods (GLOFs). These floods are highly complex phenomena, with flood characteristics controlled, in the first instance, by the style of breach formation. Downstream, GLOFs typically exhibit transient, often non-Newtonian fluid dynamics as a result of high rates of sediment entrainment from the dam structure and channel boundaries. Combined, these characteristics introduce numerous modelling challenges. In this review, the historical, contemporary and emerging approaches available to model the individual stages, or components, of a GLOF event are introduced and discussed. A number of methods exist to model the stages of a GLOF event. Dam-breach models can be categorised as being empirical, analytical or numerical in nature, with each method having significant advantages and shortcomings. Empirical relationships that produce estimates of peak discharge and time to peak are straightforward to implement, but the applicability of these models is often limited by the nature of the case study data from which they are derived. Furthermore, empirical models neglect the inclusion of basic hydraulic principles that describe the mechanics of breach formation. Analytical or parametric models simulate breach development using simplified versions of the physically based equations that describe breach enlargement, whilst complex, physically-based codes represent the state-of-the-art in numerical dam-breach modelling. To date, few of the latter have been applied to investigate the moraine-dam failure problem. Despite significant advances in the physical complexity and availability of higher-order hydrodynamic solvers, the majority of published accounts that have attempted to reconstruct or predict GLOF characteristics have been limited, often by necessity, to the use of relatively simplistic models. This is in part attributable to the unavailability of terrain models of many high-mountain catchments at the fine spatial resolutions required for the effective application of numerically-sophisticated codes, and their proprietary (and often cost-prohibitive) nature. However, advanced models are experiencing increasing use in the glacial hazards literature. In particular, the suitability of emerging mesh-free, particle-based methods for simulating dam-breach and GLOF routing may represent a solution to many of the challenges associated with modelling this complex phenomenon. Sources of uncertainty in the GLOF modelling chain have been identified by various workers. However, to date their significance for the robustness of reconstructive and predictive modelling efforts have been largely unexplored and quantified in detail. These sources include the geometric and material characterisation of moraine dam complexes, including lake bathymetry and the presence and extent of buried ice, initial conditions (freeboard, precise spillway dimensions), spatial discretisation of the down-valley domain, hydrodynamic model dimensionality and the dynamic coupling of successive components in the GLOF model cascade

Switching chemoselectivity: using mechanochemistry to alter reaction kinetics

A reaction manifold has been discovered in which the chemoselectivity can be altered by switching between neat milling and liquid assisted grinding (LAG) with polar additives. After investigation of the reaction mechanism, it has been established that this switching in reaction pathway is due to the neat mechanochemical conditions exhibiting different kinetics for a key step in the transformation. This proof of concept study demonstrates that mechanochemistry can be used to trap the kinetic product of a reaction. It is envisaged that, if this concept can be successfully applied to other transformations, novel synthetic processes could be discovered and known reaction pathways perturbed or diverted

Association between cardiorespiratory fitness and cardiometabolic risk factors in Brazilian children and adolescents: the mediating role of obesity parameters

Background There is a lack of clarity as to which obesity parameters may be more important in the association between cardiorespiratory fitness (CRF) and cardiometabolic risk factors (CMRF). Aim To verify the mediating role of different obesity parameters on the association between CRF and CMRF in normal weight and overweight/obese children and adolescents. Methods This cross-sectional study comprised 999 children and adolescents (534 boys) aged 7–14 years from the south of Brazil. Body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR) and percentage of body fat were assessed. Participants were classified as normal weight, overweight and obese according to BMI. CRF was evaluated by the 6-minute run/walk test. . A continuous CMRF score was calculated by summing the Z-scores of the following variables: systolic and diastolic blood pressure, glucose, total cholesterol, high-density lipoprotein cholesterol and triglycerides. Data analysis was performed using partial correlation and linear regression models. Results BMI, WC, WHtR and percentage of body fat mediated the relationship between CRF and CMRF in overweight/obese boys and girls but not those of normal weight. Additionally, the percentage of the influence of each obesity parameter was 20% for BMI and WC, 16% for percentage of body fat and 18% for WHtR in girls. For boys, the mediation effect was 25% for BMI, 26% for WC, 28% for percentage of body fat and 25% for WHtR. Conclusion Adiposity plays a central role in CMRF; therefore, maintaining an adequate weight status should be an important objective of health-promoting programmes in early age

School-Time Movement Behaviors and Fundamental Movement Skills in Preschoolers:An Isotemporal Reallocation Analysis

Little is known of how reallocations of time spent in different movement behaviors during preschool might relate to preschoolers’ fundamental movement skills (FMS), a key predictor of later physical activity (PA). Thus, the aim of this study was to examine (a) whether preschoolers’ school-time movement was associated with their FMS and (b) the effects on FMS of reallocating time between PA and sedentary behavior (SB). This was a cross-sectional study, using intervention data with Brazilian low-income preschoolers. We observed Brazilian preschoolers of both sexes (Mage¼ 4.5, SD¼ 0.8 years-old; 101boys) over 10 hours of school-time and objectively assessed their PA and SB with Actigraph wGT3X and their FMS with the Test of Gross Motor Development – Second Edition. We explored the associations between schooltime movement behaviors and FMS and between reallocated school-time movement behaviors and FES using compositional analysis in R (version 1.40-1), robCompositions (version 0.92-7), and lmtest (version 0.9-35) packages. This isotemporal reallocation showed that, for manipulative skills, reallocating time (5, 10, and 15 minutes, respectively) from light PA to SB was associated with increasing skill (0.14, 0.28, and 0.42 FMS units), raising questions as to whether fine motor activity occurred during SB. Thus, school-time movement significantly predicted FMS, with a modest increase in SB, at the expense of light PA eliciting improved manipulative skills

Sleep as a Priority:24-Hour Movement Guidelines and Mental Health of Chinese College Students during the COVID-19 Pandemic

Research on the combined role of 24-hour movement behaviors (sleep, sedentary behavior [SB], and physical activity) in adult mental health, though important, is in its infancy. In the context of Canadian 24-hour movement guidelines integrating quantitative recommendations for sleep, SB, and moderate-to-vigorous physical activity (MVPA), this study aimed to examine the associations between meeting guidelines and mental health among college students. The study used a cross-sectional sample of 1846 Chinese college students surveyed online in August 2020. Through network analysis and multivariate analysis of covariance, the individual and combined associations between meeting 24-hour movement guidelines and the levels of depression and anxiety after adjusting sociodemographic factors were analyzed. Results indicated that meeting the sleep guideline had stronger associations with depression and anxiety than meeting the SB or MVPA guideline. Specifically, compared to meeting no guidelines, meeting the sleep guideline (alone or in combination with other guidelines) was associated with significantly lower levels of depression and anxiety; meeting both SB and MVPA guidelines was also associated with a significantly lower level of depression. Hence, meeting more guidelines, especially adhering to a healthy sleep routine, may play an important role in promoting the mental health of young adults

Single-Molecule Imaging Reveals Aβ42:Aβ40 Ratio-Dependent Oligomer Growth on Neuronal Processes

AbstractSoluble oligomers of the amyloid-β peptide have been implicated as proximal neurotoxins in Alzheimer’s disease. However, the identity of the neurotoxic aggregate(s) and the mechanisms by which these species induce neuronal dysfunction remain uncertain. Physiologically relevant experimentation is hindered by the low endogenous concentrations of the peptide, the metastability of Aβ oligomers, and the wide range of observed interactions between Aβ and biological membranes. Single-molecule microscopy represents one avenue for overcoming these challenges. Using this technique, we find that Aβ binds to primary rat hippocampal neurons at physiological concentrations. Although amyloid-β(1–40) as well as amyloid-β(1–42) initially form larger oligomers on neurites than on glass slides, a 1:1 mix of the two peptides result in smaller neurite-bound oligomers than those detected on-slide or for either peptide alone. With 1 nM peptide in solution, Aβ40 oligomers do not grow over the course of 48 h, Aβ42 oligomers grow slightly, and oligomers of a 1:1 mix grow substantially. Evidently, small Aβ oligomers are capable of binding to neurons at physiological concentrations and grow at rates dependent on local Aβ42:Aβ40 ratios. These results are intriguing in light of the increased Aβ42:Aβ40 ratios shown to correlate with familial Alzheimer’s disease mutations

Associations of cigarette smoking with subclinical inflammation and atherosclerosis : ELSA-Brasil (The Brazilian Longitudinal Study of Adult Health)

Background-—There is a need to identify sensitive biomarkers of early tobacco-related cardiovascular disease. We examined the association of smoking status, burden, time since quitting, and intensity, with markers of inflammation and subclinical atherosclerosis. Methods and Results-—We studied 14 103 participants without clinical cardiovascular disease in ELSA-Brasil (Brazilian Longitudinal Study of Adult Health). We evaluated baseline cross-sectional associations between smoking parameters and inflammation (highsensitivity C-reactive protein [hsCRP]) and measures of subclinical atherosclerosis (carotid intima–media thickness, ankle-brachial index, and coronary artery calcium [CAC]). The cohort included 1844 current smokers, 4121 former smokers, and 8138 never smokers. Mean age was 51.7 8.9 years; 44.8% were male. After multivariable adjustment, compared with never smokers, current smokers had significantly higher levels of hsCRP (b=0.24, 0.19–0.29 mg/L; P0 (odds ratio: 1.83; 95% confidence interval, 1.46–2.30; P0 were lower with increasing time since quitting (P0 (P=0.03) after adjusting for duration of smoking. Conclusions-—Strong associations were observed between smoking status, burden, and intensity with inflammation (hsCRP) and subclinical atherosclerosis (carotid intima–media thickness, ankle-brachial index, CAC). These markers of early cardiovascular disease injury may be used for the further study and regulation of traditional and novel tobacco products

24- hour movement behaviors and fitness in preschoolers: acompositional and isotemporal reallocation analysis

This study analyzed the associations between the 24-hour movement behaviors composition and fitness in preschoolers and investigated predicted changes in fitness when time in active behaviors is reallocated. This cross-sectional study was carried out with 270 preschoolers (132 boys; 3.97 ± 0.80 years-old). Light and moderate-to-vigorous physical activity (LPA and MVPA), and sedentary behavior (SB) were verified using an accelerometer. Sleep time was obtained through interviews with parents. Components of physical fitness (cardiorespiratory fitness—CRF, speed-agility, and lower-body muscular strength) were assessed using the PREFIT Battery. To verify the association between 24-hour movement behaviors and physical fitness, the compositional analysis was used, and for the time reallocation, the compositional isotemporal substitution analysis was used for active behaviors (LPA and MVPA). The daily composition, adjusted for body mass index, sex, and age, was significantly associated with CRF (P = .007; r2 = 0.29), speed-agility (P < .001; r2 = 0.14), and lower-body muscular strength (P = .01; r2 = 0.07). For CRF, the addition of MVPA, at the expense of any other behavior, was associated with significant improvements. For speed-agility and lower-body muscular strength, only reallocations between sleep and LPA yielded significant associations. The variation in CRF, speed-agility, and lower-body muscular strength was associated with the 24 hours movement composition, and reallocating 5, 10 or 15 minutes of SB or sleep for MVPA was significantly positive for CRF (P < .05). The present findings highlight the relevance of decreasing SB and increasing physical activity practice, particularly at high intensities, to promote a better CRF profile for preschoolers