THE EFFECT OF EXHAUSTIVE RUNNING ON POSTURAL DYNAMICS

Recently, researchers have begun to use nonlinear measures such as the Lyapunovexponent (LyE) and Approximate Entropy (ApEn) to examine temporal structure in the continuous behavior of biological systems. When using these measures a higher score indicates lesser periodicity and greater chaotic behavior. A decrease in LyE and ApEn values have been shown in some cases to indicate pathological conditions. Studies of postural control have found that after a cerebral concussion, an athlete’s center of pressure oscillations measured by ApEn are significantly decreased even up to 96 hours post-injury as compared with their preseason ApEn scores, even when the athlete appears steady (Cavanaugh, 2006). In regards to walking gate, local dynamic stability showed decreased variability when assessed amongst ACL reconstruction patients (Stergiou, 2004). The purpose of the current experiment ıs to use ApEn versus a set of traditional postural measure to evaluate a postural sway during upright stance prior to and following a bout of exhaustive running. In published balance studies only about 50% report significant improvements, possibly because traditional measures aren’t capturing the improvements in postural control. Promising results from the above cited studies indicate that nonlinear measures may be measuring elements that the traditional measures don’t detect

BALANCE TRAINING ALTERS POSTURAL DYNAMICS UNIQUELY FOR STANCE ON COMPLIANT VS. NON-COMPLIANT SURFACES

Balance training is a common clinical modality used for improving postural control and preventing injury during sports training and participation. However, a number of empirical studies have failed to support the efficacy of balance training. One factor that may have limited the previous empirical studies is a lack of sensitivity with regard to the traditional descriptive statistics used to characterize postural control. Recent developments in non-linear dynamic analyses have led researchers to revaluate the way in which postural control is measured and understood. The advantage of nonlinear analyses for assessing postural behavior is their sensitivity to changes in the time-dependent structures of continuous postural sway. Lyapunov Exponent (LyE) is defined as the slope of the average logarithmic divergence of neighboring trajectories in a state space (Wolf, 1985). The purpose of this study was to evaluate the effects of balance training on postural control in a healthy population using both a traditional (position variability; as measured by standard deviation) and non-linear (Lyapunov Exponent; LyE) measure of postural sway variability

EFFECT OF RESPIRATION DYNAMICS ON POSTURAL CONTROL FOLLOWING A 5K RUN

Research has shown postural control during upright stance can be diminished for up to twenty minutes following aerobic exercise of different types, intensities, and durations (Lepers et al., 1997; Nagy et al., 2002). Researchers have posited that this is caused by neuromuscular changes associated with aerobic exercise and fatigue such as the reduced excitability and central drive to peripheral muscles (Lepers et al., 2002), vestibular desensitization (Lepers et al., 1997), and peripheral somatosensory desensitization (Lepers et al., 1997). However, no research has measured or attempted to control for the influence that changes in respiration dynamics (e.g., rate and volume) alone might have on postural sway. The aim of the current study was to examine these effects in order decipher whether changes to postural control following intense aerobic exercise (a 5-kilometer run performed with maximal effort) can be attributed to effects of exercise and fatigue or simply changes in respiration

Bounds on Quantum Correlations in Bell Inequality Experiments

Bell inequality violation is one of the most widely known manifestations of entanglement in quantum mechanics; indicating that experiments on physically separated quantum mechanical systems cannot be given a local realistic description. However, despite the importance of Bell inequalities, it is not known in general how to determine whether a given entangled state will violate a Bell inequality. This is because one can choose to make many different measurements on a quantum system to test any given Bell inequality and the optimization over measurements is a high-dimensional variational problem. In order to better understand this problem we present algorithms that provide, for a given quantum state, both a lower bound and an upper bound on the maximal expectation value of a Bell operator. Both bounds apply techniques from convex optimization and the methodology for creating upper bounds allows them to be systematically improved. In many cases these bounds determine measurements that would demonstrate violation of the Bell inequality or provide a bound that rules out the possibility of a violation. Examples are given to illustrate how these algorithms can be used to conclude definitively if some quantum states violate a given Bell inequality.Comment: 13 pages, 1 table, 2 figures. Updated version as published in PR

TRAINING FOR THE BIKE TO RUN TRANSITION IN TRIATHLON

The purpose of this study was to examine the effect of a practice regimen that targets the bike-to-run transition for triathlons; known as brick workouts. The principle of specificity suggests that since this skill is a critical transition in a triathlon, having further impact on the subsequent running section, practicing this skill is vital for success. Moreover, the identification of performance parameters that quantify a successful transition will serve to maximize practice efficiency. Subjects (N=12) performed either brick workouts or single event training, to examine their effects on the bike-run transition. Our results indicate that the brick workouts had a positive effect by eliciting an increased adaptability in knee behavior in response to the transition from cycling to running. Quicker adoption of efficient running mechanics may ensue, leading to less fatigue and greater performance

What Provides Justification for Cheating:Producing or Observing Counterfactuals?

When people can profit financially by lying, they do so to the extent to which they can justify their lies. One type of justification is the observation and production of desirable counterfactual information. Here, we disentangle observing and producing of desired counterfactuals and test whether the mere observation is sufficient or whether one actually needs to produce the information in order to justify lying. By employing a modified version of the Die-Under-Cup task, we ask participants to privately roll a die three times and to report the outcome of the first die roll (with higher values corresponding to higher payoffs). In all three conditions, participants produce (roll the die) and observe the first die roll, which is relevant for pay. We manipulate whether participants produce and observe versus only observe the second and third die roll outcomes, which are both irrelevant for pay. Results reveal that people lie to the same extent—when producing and observing the counterfactuals, and when merely observing them. It seems that merely observing counterfactual information is sufficient to allow people to use this information to justify their lies. We further test whether creativity and moral disengagement are associated with dishonesty and replicate the finding showing that unethical behavior increases with creativity

Symbolic-Numeric Algorithms for Computer Analysis of Spheroidal Quantum Dot Models

A computation scheme for solving elliptic boundary value problems with axially symmetric confining potentials using different sets of one-parameter basis functions is presented. The efficiency of the proposed symbolic-numerical algorithms implemented in Maple is shown by examples of spheroidal quantum dot models, for which energy spectra and eigenfunctions versus the spheroid aspect ratio were calculated within the conventional effective mass approximation. Critical values of the aspect ratio, at which the discrete spectrum of models with finite-wall potentials is transformed into a continuous one in strong dimensional quantization regime, were revealed using the exact and adiabatic classifications.Comment: 6 figures, Submitted to Proc. of The 12th International Workshop on Computer Algebra in Scientific Computing (CASC 2010) Tsakhkadzor, Armenia, September 5 - 12, 201

Mirror formation control in the vicinity of an asteroid

Two strategies are presented for the positioning and control of a spacecraft formation designed to focus sunlight onto a point on the surface of asteroid, thereby sublimating the material and ejecting debris creating thrust. In the first approach, the formation is located at artficial equilibrium points around the asteroid and controlled using the force from the solar radiation pressure. The second approach determines the optimal periodic formation orbits, subject to the gravitational perturbations from the asteroid, the solar radiation pressure and the control acceleration derived from a control law

Incidence and treatment costs of severe bacterial infections among people who inject heroin: A cohort study in South London, England.

BACKGROUND: People who inject drugs often get bacterial infections. Few longitudinal studies have reported the incidence and treatment costs of these infections. METHODS: For a cohort of 2335 people who inject heroin entering treatment for drug dependence between 2006 and 2017 in London, England, we reported the rates of hospitalisation or death with primary causes of cutaneous abscess, cellulitis, phlebitis, septicaemia, osteomyelitis, septic arthritis, endocarditis, or necrotising fasciitis. We compared these rates to the general population. We also used NHS reference costs to calculate the cost of admissions. RESULTS: During a median of 8.0 years of follow-up, 24 % of patients (570/2335) had a severe bacterial infection, most commonly presenting with cutaneous abscesses or cellulitis. Bacterial infections accounted for 13 % of all hospital admissions. The rate was 73 per 1000 person-years (95 % CI 69-77); 50 times the general population, and the rate remained high throughout follow-up. The rate of severe bacterial infections for women was 1.50 (95 % CI 1.32-1.69) times the rate for men. The mean cost per admission was £4980, and we estimate that the annual cost of hospital treatment for people who inject heroin in London is £4.5 million. CONCLUSIONS: People who inject heroin have extreme and long-term risk of severe bacterial infections