The Relationship Between Heart Rate Variability and Skeletal Muscle Damage in Female Collegiate Athletes

Heart rate variability (HRV) is an accurate indicator of sympathetic and parasympathetic nervous system activity. With athletes, HRV analysis can be a useful tool in analyzing the readiness to train, recovery status, and chronic adaptations to training, and overtraining. Skeletal muscle damage, which can be an outcome of overtraining, may be assessed using biomarkers in the blood, including creatine kinase (CK). The relationship between skeletal muscle damage and measures of HRV with regards to performance is not known. PURPOSE: The purpose of this study was to determine the relationships between HRV measures and serum CK concentrations. A secondary purpose of this study was to determine what lifestyle factors, other than physical activity levels, may affect HRV measures and serum CK concentrations in the same population. METHODS: Six Female NCAA Division II Volleyball athletes completed the 14-day study. Participants recorded HRV with the use of the Cardiomood smartphone application daily, upon waking, throughout the study. Time domain (i.e., RMSSD) and frequency domain (i.e., low, high, total power) variables were recorded to characterize HRV. Blood samples were collected in an unfasted state at 7 time points throughout the study and analyzed for total CK level (U/L). In addition, a wellness questionnaire completed daily included questions pertaining to fatigue (F), mood (M), stress (ST), soreness (MS), sleep duration (S), sleep quality (SQ), and hydration (H). During structured practice and workout sessions, energy expenditure (EE) was measured using a chest worn monitor. A Pearson product-moment correlation was performed to investigate the relationships among variables with significance set at 0.05. RESULTS: Total CK levels were found to have a significant negative relationship with RMSSD (p = 0.035), and a positive relationship with EE (p \u3c 0.01) and MS (p \u3c 0.01). A significant negative relationship with RMSD and SQ (p = 0.01), and a significant positive relationship with RMSSD and M (p = 0.008) was also found. Within the wellness questionnaire, MS and H had a significant negative relationship (p = 0.021) and M had a significant positive relationship with S (p = 0.038). CONCLUSION: The use of HRV may serve as an accurate monitor of total circulating CK levels in the blood. With regards to the wellness questionnaire, it was found that sleep quality had the largest influence on HRV, reinforcing the importance of sleep and recovery. These results could prove beneficial for coaches in assessing an athlete’s readiness to train and recovery status

Estimation of trace gas fluxes with objectively determined basis functions using reversible-jump Markov chain Monte Carlo

Atmospheric trace gas inversions often attempt to attribute fluxes to a high-dimensional grid using observations. To make this problem computationally feasible, and to reduce the degree of under-determination, some form of dimension reduction is usually performed. Here, we present an objective method for reducing the spatial dimension of the parameter space in atmospheric trace gas inversions. In addition to solving for a set of unknowns that govern emissions of a trace gas, we set out a framework that considers the number of unknowns to itself be an unknown. We rely on the well-established reversible-jump Markov chain Monte Carlo algorithm to use the data to determine the dimension of the parameter space. This framework provides a single-step process that solves for both the resolution of the inversion grid, as well as the magnitude of fluxes from this grid. Therefore, the uncertainty that surrounds the choice of aggregation is accounted for in the posterior parameter distribution. The posterior distribution of this transdimensional Markov chain provides a naturally smoothed solution, formed from an ensemble of coarser partitions of the spatial domain. We describe the form of the reversible-jump algorithm and how it may be applied to trace gas inversions. We build the system into a hierarchical Bayesian framework in which other unknown factors, such as the magnitude of the model uncertainty, can also be explored. A pseudo-data example is used to show the usefulness of this approach when compared to a subjectively chosen partitioning of a spatial domain. An inversion using real data is also shown to illustrate the scales at which the data allow for methane emissions over north-west Europe to be resolved

The Relationship of Physiological and Fitness Variables to Performance in CrossFit®-based Exercise: Preliminary Findings

CrossFit® is a rapidly expanding exercise program as well as an emerging competitive sport. Little is known regarding the correlation of physical fitness measures and performance in CrossFit®-based events. PURPOSE: The purpose of this study was to determine the relationship between various physiological and fitness variables and performance in a typical CrossFit®-based workout. METHODS: Nine male participants (age = 32.2 ± 3.6 yrs; height = 173.1 ± 9.8 cm; weight = 86.1 ± 11.6 kg; BMI = 28.6 ± 1.2 kg/m2) who had performed CrossFit® as their primary exercise program at least 3 days/week for the past 12 months were recruited. Participants performed a test of maximal aerobic fitness (VO2max), a Wingate test, a DEXA scan, a 1RM Clean and Jerk, and a series of exercises that would typically be included in a CrossFit®-based workout. More specifically, participants performed 15 Wall Ball exercises (20 lbs.), 15 Box Jumps (24 in.), 10 Burpees over a barbell, and 10 Kipping Pullups. If all exercises were completed, the participants repeated the exercises in the same order. The participants were asked to stop after 12 min, and the total number of repetitions completed was recorded. Questions regarding the participants’ exercise history and dietary habits were asked. Spearman’s correlation was used to identify relationships between the variables and performance (number of repetitions completed) during the CrossFit®-based workout. Participants were also grouped into “high” (≥ median) or “low” (\u3c median) groups, and independent samples t-tests were used to compare how each group performed during the CrossFit®-based workout. Statistical significance was set at .05. RESULTS: Performance during the CrossFit®-based workout had strong, positive relationships with strength-to-body weight ratio (r = .686; p = .041), 1RM Clean and Jerk (r = .915; p = .001), and years of experience (r = .869; p = .002). Participants with higher strength-to-body weight ratios (p = .036), lower fatigue index (p = .022), lower body fat percentage (p = .022), higher weight lifted during the 1RM Clean and Jerk (p = .017), and more years of experience (p = .027) completed more repetitions during the CrossFit®-based workout. Significance was not found with any other variable. CONCLUSION: Based on these early findings, anaerobic fatigue resistance, body fat percentage, muscular power, and exercise history appear to be significant predictors of performance in CrossFit®-based workouts

Astronomy below the survey threshold in the SKA era

Astronomy at or below the 'survey threshold' has expanded significantly since the publication of the original 'Science with the Square Kilometer Array' in 1999 and its update in 2004. The techniques in this regime may be broadly (but far from exclusively) defined as 'confusion' or 'P(D)' analyses (analyses of one-point statistics), and 'stacking', accounting for the flux-density distribution of noise-limited images co-added at the positions of objects detected/isolated in a different waveband. Here we discuss the relevant issues, present some examples of recent analyses, and consider some of the consequences for the design and use of surveys with the SKA and its pathfinders

Abrupt reversal in emissions and atmospheric abundance of HCFC-133a (CF3CH2Cl)

Hydrochlorofluorocarbon HCFC-133a (CF3CH2Cl) is an anthropogenic compound whose consumption for emissive use is restricted under the Montreal Protocol. A recent study showed rapidly increasing atmospheric abundances and emissions. We report that, following this rise, the at- mospheric abundance and emissions have declined sharply in the past three years. We find a Northern Hemisphere HCFC-133a increase from 0.13 ppt (dry air mole fraction in parts-per-trillion) in 2000 to 0.50 ppt in 2012–mid-2013 followed by an abrupt reversal to 0.44 ppt by early 2015. Global emissions derived from these observations peaked at 3.1 kt in 2011, followed by a rapid decline of 0.5 kt yr−2 to 1.5 kt yr−1 in 2014. Sporadic HCFC-133a pollution events are detected in Europe from our high-resolution HCFC-133a records at three European stations, and in Asia from sam- ples collected in Taiwan. European emissions are estimated to be <0.1 kt yr−1 although emission hotspots were identi- fied in France

Association of severity of primary open-angle glaucoma with serum vitamin D levels in patients of African descent.

PurposeTo study the relationship between primary open-angle glaucoma (POAG) in a cohort of patients of African descent (AD) and serum vitamin D levels.MethodsA subset of the AD and glaucoma evaluation study III (ADAGES III) cohort, consisting of 357 patients with a diagnosis of POAG and 178 normal controls of self-reported AD, were included in this analysis. Demographic information, family history, and blood samples were collected from all the participants. All the subjects underwent clinical evaluation, including visual field (VF) mean deviation (MD), central cornea thickness (CCT), intraocular pressure (IOP), and height and weight measurements. POAG patients were classified into early and advanced phenotypes based on the severity of their visual field damage, and they were matched for age, gender, and history of hypertension and diabetes. Serum 25-Hydroxy (25-OH) vitamin D levels were measured by enzyme-linked immunosorbent assay (ELISA). The association of serum vitamin D levels with the development and severity of POAG was tested by analysis of variance (ANOVA) and the paired t-test.ResultsThe 178 early POAG subjects had a visual field MD of better than -4.0 dB, and the 179 advanced glaucoma subjects had a visual field MD of worse than -10 dB. The mean (95% confidence interval [CI]) levels of vitamin D of the subjects in the control (8.02 ± 6.19 pg/ml) and early phenotype (7.56 ± 5.74 pg/ml) groups were significantly or marginally significantly different from the levels observed in subjects with the advanced phenotype (6.35 ± 4.76 pg/ml; p = 0.0117 and 0.0543, respectively). In contrast, the mean serum vitamin D level in controls was not significantly different from that of the subjects with the early glaucoma phenotype (p = 0.8508).ConclusionsIn this AD cohort, patients with advanced glaucoma had lower serum levels of vitamin D compared with early glaucoma and normal subjects

The Link Between the Hidden Broad Line Region and the Accretion Rate in Seyfert 2 Galaxies

In the past few years more and more pieces of evidence have been presented for a revision of the widely accepted Unified Model of Active Galactic Nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In the following, we will present evidence that accretion rate is also a key parameter for the presence of Hidden Broad Line Regions in Seyfert 2 galaxies. Our sample consists of 21 sources with polarized Hidden Broad Lines and 18 sources without Hidden Broad Lines. We use stellar velocity dispersions from several studies on the CaII and Mg b triplets in Seyfert 2 galaxies, to estimate the mass of the central black holes via the Mbh-{\sigma}\ast relation. The ratio between the bolometric luminosity, derived from the intrinsic (i.e. unabsorbed) X-ray luminosity, and the Eddington luminosity is a measure of the rate at which matter accretes onto the central supermassive black hole. A separation between Compton-thin HBLR and non-HBLR sources is clear, both in accretion rate (log Lbol/LEdd = -1.9) and in luminosity (log Lbol = 43.90). When, properly luminosity-corrected, Compton-thick sources are included, the separation between HBLR and non-HBLR is less sharp but no HBLR source falls below the Eddington ratio threshold. We speculate that non-HBLR Compton-thick sources with accretion rate higher than the threshold, do possess a BLR, but something, probably related to their heavy absorption, is preventing us from observing it even in polarized light. Our results for Compton-thin sources support theoretical expectations. In a model presented by Nicastro (2000), the presence of broad emission lines is intrinsically connected with disk instabilities occuring in proximity of a transition radius, which is a function of the accretion rate, becoming smaller than the innermost stable orbit for very low accretion rates and therefore luminosities.Comment: 23 pages, 4 figure