Bounds on spectral dispersion from fermi-detected gamma ray bursts

Data from four Fermi-detected gamma-ray bursts (GRBs) are used to set limits on spectral dispersion of electromagnetic radiation across the Universe. The analysis focuses on photons recorded above 1 GeV for Fermi-detected GRB 080916C, GRB 090510A, GRB 090902B, and GRB 090926A because these high-energy photons yield the tightest bounds on light dispersion. It is shown that significant photon bunches in GRB 090510A, possibly classic GRB pulses, are remarkably brief, an order of magnitude shorter in duration than any previously claimed temporal feature in this energy range. Although conceivably a\u3e3σ fluctuation, when taken at face value, these pulses lead to an order of magnitude tightening of prior limits on photon dispersion. Bound of Δc/c\u3c6.94×10−21 is thus obtained. Given generic dispersion relations where the time delay is proportional to the photon energy to the first or second power, the most stringent limits on the dispersion strengths were k1\u3c1.61×10−5  sec Gpc−1 GeV−1 and k2\u3c3.57×10−7  sec Gpc−1 GeV−2, respectively. Such limits constrain dispersive effects created, for example, by the spacetime foam of quantum gravity. In the context of quantum gravity, our bounds set M1c2 greater than 525 times the Planck mass, suggesting that spacetime is smooth at energies near and slightly above the Planck mass

Does Body Mass Index Influence the Physiological and Perceptual Demands Associated with Defensive Tactics Training in State Patrol Officers?

International Journal of Exercise Science 11(6): 319-330, 2018. The purpose of this investigation was to determine the physiological and perceptual demands associated with defensive tactics (DEFTAC) training among state patrol officers of different BMI (body mass index) categories. Twenty-four male state patrol officers (n = 24, age 36.00 + 7.86 yrs) voluntarily agreed to participate in data collection during a DEFTAC gauntlet. Anthropometric information (height (HT) 182.19 + 7.43 cm and weight (WT) 96.31 + 17.45 kg), body mass index (BMI), peak and average heart rates, duty weight, BLa, and RPE, were recorded. Officers were then divided into two-groups (Healthy BMI (BMI ≤ 25), n = 12, Overweight (BMI ≥ 25), n = 12). Analyses of covariance (ANCOVAs) were conducted to determine the effect of BMI on the outcome variables. Furthermore, a Pearson’s product-moment correlation coefficient was also conducted to determine if significant relationships between RPE, BLa, and HR existed between groups. Significant mean score differences between healthy and overweight officers were found in measures of age [t(22) 4.12, p\u3c 0.01, R2 = .44], and weight of duty gear [t(21) 3.96, p\u3c0.01, R2 = .33]. When used as a covariate, age also predicted average HR% [ F(1, 21) = 6.19, p \u3c .05, partial η2 = .24]. Significant relationships were found in the healthy group between RPE and DEFTAC time, DEFTAC time and score, as well as score and post BLa. Significant relationships for the overweight group between peak (HR) percentage and post BLa, peak (HR) percentage and RPE, DEFTAC time and duty weight, and between weight and DEFTAC time. The results of this study suggest that overweight officers may have lower DEFTAC scores when compared to their healthy counterparts. Based on the results, it seems reasonable to compare physiological variables from this population to those from combative sports as well as for officers to achieve and maintain a healthy BMI value in order to improve individual DEFTAC performance

INVESTIGATING DRILL CONSTRAINT KINEMATICS IN MALE BASEBALL PITCHERS USING MARKERLESS MOTION CAPTURE

This study investigated the kinematic differences that pitching constraint drills elicit compared to a baseball pitch. 18 male baseball pitchers with average height (183.7 ± 5.2cm), weight (87.4 ± 9.6kg), and skill level (Professional (4), Collegiate (5), High School (9)) were included. Video was recorded using a single camera from the open side. Each pitcher threw 3 maximum effort pitches from a mound. Next, 3 maximum effort throws were recorded for 8 different throwing drills: medicine ball hook’em drill, pivot pickoff drill, foot-up rocker drill, walk-in drill, towel drill, janitor drill, drop-step drill, and long toss. Videos were processed using pitchAITM, a markerless motion capture solution. The medicine ball hook’em drill was the most different to a pitch, and the towel drill was the most similar. This work demonstrates the first collective approach to studying the biomechanics of frequently used baseball pitching constraint drills

The Impact Of External Loads Carried By Police Officers On Vertical Jump Performance

International Journal of Exercise Science 13(6): 1179-1189, 2020. The purpose of this study was to examine the impact that external loads have on vertical jump height and peak anaerobic power output (PAPw) of police officers during a vertical jump (VJ) test. Retrospective data of 47 (mean age 38.79 ± 7.97 years) police officers from a US Law Enforcement Agency (LEA) were used for analysis. VJ heights and body mass were used in the Sayers Peak Power Equation to calculate PAPw. Power-to-weight (P:W) ratios were then calculated by dividing PAPw by the officer’s body mass. VJ height significantly (p \u3c .001) decreased with load (unloaded = 49.49 ± 8.46 cm: loaded = 43.62 ± 7.68 cm). A Pearson’s correlation showed a significant (p \u3c .01) low-moderate (r = .387) relationship between absolute load (9.57 ± .94 kg) and change in PAPw, and a significant (p \u3c .01) strong (r = .794) correlation between relative load and changes in P:W. This study supports previous research that suggests that occupational load carriage has a negative impact on VJ performance in police officers and may influence job performance, and that training programs may mitigate these negative effects

Biochemical Validation of Patient-Reported Symptom Onset Time in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

AbstractObjectivesThis study evaluated a biochemical validation of patient-reported symptom onset time in patients with ST-segment elevation myocardial infarction (STEMI).BackgroundSymptom onset time is an important metric but has never been formally validated.MethodsThe Mayo Clinic Percutaneous Coronary Intervention (PCI) Registry was interrogated to obtain baseline, procedural, and outcome data on 607 STEMI patients undergoing primary PCI. Biochemical onset time was determined by backward extrapolation of serial increasing cardiac troponin T (cTnT) measurements.ResultsThe median patient-reported onset time was 12 min later than the calculated time of first cTnT increase and was therefore estimated to be 4.2 h later than the biochemical onset time (interquartile range: 1.9 to 11.1 h; p < 0.001), assuming a 4-h interval between coronary occlusion and first cTnT increase. Conventional ischemic time showed no association with infarct size (correlation with peak cTnT: r = 0.023; p = 0.61) or 1-year mortality (hazard ratio: 0.97 per doubling; 95% confidence interval: 0.68 to 1.40; p = 0.88). However, after recalculation of ischemic time with biochemical onset time, significant associations with infarct size (r = 0.14; p = 0.001) and 1-year mortality (hazard ratio: 1.70 per doubling; 95% confidence interval: 1.20 to 2.40; p = 0.003) were found. When underestimation of ischemic time by patient-reported onset time increased, so did the risk of mortality.ConclusionsAlthough our point estimate should be interpreted with caution, our study indicates that the actual onset of STEMI is likely to be earlier than the patient-reported onset time. Recalculation of ischemic time with biochemical onset time greatly enhanced its prognostic value. Underestimation of ischemic time by patient-reported onset time occurred more often in high-risk patients

The Impact of Formal Strength and Conditioning on the Fitness of Law Enforcement Recruits: A Retrospective Cohort Study

International Journal of Exercise Science 13(4): 1615-1629, 2020. Research involving law enforcement populations has suggested better fitness could enhance job task performance and reduce injuries. Academy training should lead to improvements in recruit fitness. The aim of this study was to investigate the impact of a strength and conditioning program on fitness among law enforcement recruits. Twenty-six recruits (23 males, three females) completed a 27-week academy, which incorporated 3-4 physical training sessions per week. Fitness assessment occurred during pre- (week 0), mid- (week 14), and post-testing (week 27) time points. The fitness assessments included: vertical jump, one-minute push-ups, one-minute sit-ups, posterior chain strength measured by a leg/back dynamometer, grip strength, and aerobic fitness measured by the 20-m multistage shuttle run (MSR). A repeated measures ANOVA with Bonferroni post hoc tests determined any significant changes in fitness between time points, with alpha set at p \u3c .05. Due to the small sample size of females, statistical analysis was only conducted on male recruits. Overall, significant main effects (p \u3c .001) were observed in all fitness assessments except for grip strength. The results detailed general improvements in fitness. However, push-up and MSR scores decreased from mid- to post-test, while sit-ups did not change. Posterior chain strength and the vertical jump improved from mid- to post-test. The data indicated that the strength and conditioning program positively influenced the fitness of recruits. An increased focus on skill-specific work in the second-half of academy may have contributed to the plateaus in muscular endurance and aerobic fitness, and improvement of lower-body strength and power

Parkinson\u27s disease and the gastrointestinal microbiome

Recently, there has been a surge in awareness of the gastrointestinal microbiome (GM) and its role in health and disease. Of particular note is an association between the GM and Parkinson’s disease (PD) and the realisation that the GM can act via a complex bidirectional communication between the gut and the brain. Compelling evidence suggests that a shift in GM composition may play an important role in the pathogenesis of PD by facilitating the characteristic ascending neurodegenerative spread of α-synuclein aggregates from the enteric nervous system to the brain. Here, we review evidence linking GM changes with PD, highlighting mechanisms supportive of pathological α-synuclein spread and intestinal inflammation in PD. We summarise existing patterns and correlations seen in clinical studies of the GM in PD, together with the impacts of non-motor symptoms, medications, lifestyle, diet and ageing on the GM. Roles of GM modulating therapies including probiotics and faecal microbiota transplantation are discussed. Encouragingly, alterations in the GM have repeatedly been observed in PD, supporting a biological link and highlighting it as a potential therapeutic target

Individual Differences in Reinforcement Learning: Behavioral, Electrophysiological, and Neuroimaging Correlates

During reinforcement learning, phasic modulations of activity in midbrain dopamine neurons are conveyed to the dorsal anterior cingulate Cortex (dACC) and basal ganglia (BG) and serve to guide adaptive responding. While the animal literature supports a role for the dACC in integrating reward history over time, most human electrophysiological Studies of dACC function have focused on responses to single positive and negative outcomes. The present electrophysiological study investigated the role of the dACC in probabilistic reward learning in healthy subjects using a task that required integration of reinforcement history over time. We recorded the feedback-related negativity (FRN) to reward feedback in subjects who developed a response bias toward a more frequently rewarded ("rich") stimulus ("learners") versus subjects who did not ("non-learners"). Compared to non-learners, learners showed more positive (i.e., smaller) FRNs and greater dACC activation upon receiving reward for correct identification of the rich stimulus. In addition, dACC activation and a bias to select the rich Stimulus were positively correlated. The same participants also completed a monetary incentive delay (MID) task administered during functional magnetic resonance imaging. Compared to non-learners, learners displayed stronger BG responses to reward in the MID task. These findings raise the possibility that learners in the probabilistic reinforcement task were characterized by stronger dACC and BG responses to rewarding outcomes. Furthermore, these results highlight the importance of the dACC to probabilistic reward learning in humans.Psycholog