The effect of a period of intense exercise on the marker approach to detect growth hormone doping in sports.

The major objective of this study was to investigate the effects of several days of intense exercise on the growth hormone marker approach to detect doping with human growth hormone (hGH). In addition we investigated the effect of changes in plasma volume on the test. Fifteen male athletes performed a simulated nine-day cycling stage race. Blood samples were collected twice daily over a period of 15 days (stage race + three days before and after). Plasma volumes were estimated by the optimized CO Rebreathing method. IGF-1 and P-III-NP were analyzed by Siemens Immulite and Cisbio Assays, respectively. All measured GH 2000 scores were far below the published decision limits for an adverse analytical finding. The period of exercise did not increase the GH-scores; however the accompanying effect of the increase in Plasma Volume yielded in essentially lower GH-scores. We could demonstrate that a period of heavy, long-term exercise with changes in plasma volume does not interfere with the decision limits for an adverse analytical finding. Copyright © 2014 John Wiley & Sons, Ltd.

Mean first-passage time of continuous non-Markovian processes driven by colored noise

An equation for mean first-passage times of non-Markovian processes driven by colored noise is derived through an appropriate backward integro-differential equation. The equation is solved in a Bourret-like approximation. In a weak-noise bistable situation, non-Markovian effects are taken into account by an effective diffusion coefficient. In this situation, our results compare satisfactorily with other approaches and experimental data.

Coherence and anticoherence resonance tunned by noise

We present numerical evidence and a theoretical analysis of the appearance of anticoherence resonance induced by noise, not predicted in former analysis of coherence resonance. We have found that this phenomenon occurs for very small values of the intensity of the noise acting on an excitable system, and we claim that this is a universal signature of a nonmonotonous relaxational behavior near its oscillatory regime. Moreover, we demonstrate that this new phenomenon is totally compatible with the standard situation of coherence resonance appearing at intermediate values of noise intensity.

Excitability transitions and wave dynamics under spatiotemporal structured noise

We present an analytic and numerical study of the effects of external fluctuations in active media. Our analytical methodology transforms the initial stochastic partial differential equations into an effective set of deterministic reaction-diffusion equations. As a result we are able to explain and make quantitative predictions on the systematic and constructive effects of the noise, for example, target patterns created out of noise and traveling or spiral waves sustained by noise. Our study includes the case of realistic noises with temporal and spatial structures.

Suppression of scroll wave turbulence by noise

Rotating scroll waves are dynamical spatiotemporal structures characteristic of three-dimensional active media. It is well known that, under low excitability conditions, scroll waves develop an intrinsically unstable dynamical regime that leads to a highly disorganized pattern of wave propagation. Such a ¿turbulent¿ state bears some resemblance to fibrillation states in cardiac tissue. We show here that this unstable regime can be controlled by using a spatially distributed random forcing superimposed on a control parameter of the system. Our results are obtained from numerical simulations but an explicit analytical argument that rationalizes our observations is also presented.

Noise-enhanced excitability in bistable activator-inhibitor media

We show that external fluctuations induce excitable behavior in a bistable spatially extended system with activator-inhibitor dynamics of the FitzHugh-Nagumo type. This can be understood as a mechanism for sustained signal propagation in bistable media. The phase diagram of the stochastic system is analytically obtained and numerically verified. For small-noise intensities, front propagation becomes unstable, and excitable pulses arise as the only possible spatiotemporal behavior of the system. For large-noise intensities, on the other hand, the system enters an effective regime of oscillatory behavior, where it exhibits spontaneous nucleation of pulses and synchronized firing.

Dynamics of sweeping through an instability: Passage-time statistics for colored noise

A calculation of passage-time statistics is reported for the laser switch-on problem, under the influence of colored noise, when the net gain is continuously swept from below to above threshold. Cases of fast and slow sweeping are considered. In the weak-noise limit, asymptotic results are given for small and large correlation times of the noise. The mean first passage time increases with the correlation time of the noise. This effect is more important for fast sweeping than for slow sweeping.

Noise-induced Brownian motion of spiral waves

We study the erratic displacement of spiral waves forced to move in a medium with random spatiotemporal excitability. Analytical work and numerical simulations are performed in relation to a kinematic scheme, assumed to describe the autowave dynamics for weakly excitable systems. Under such an approach, the Brownian character of this motion is proved and the corresponding dispersion coefficient is evaluated. This quantity shows a nontrivial dependence on the temporal and spatial correlation parameters of the external fluctuations. In particular, a resonantlike behavior is neatly evidenced in terms of the noise correlation time for the particular situation of spatially uniform fluctuations. Actually, this case turns out to be, to a large extent, exactly solvable, whereas a pair of dispersion mechanisms are discussed qualitatively and quantitatively to explain the results for the more general scenario of spatiotemporal disorder.

Multiplicative noise effects on relaxations from marginal states

Relaxational processes in bistable potentials close to marginal conditions are studied under the combined effect of additive and multiplicative fluctuations. Characteristic time scales associated with the first-passage-time-distribution are analytically obtained. Multiplicative noise introduces large effects on the characteristic decay times, which is particularly significant when relaxations are mediated by fluctuations, i.e., below marginality and for small noise intensity. The relevance of our approach with respect to realistic chemical bistable systems experimentally operated under external noise influences is mentioned.

Regular wave propagation out of noise in chemical active media

A pacemaker, regularly emitting chemical waves, is created out of noise when an excitable photosensitive Belousov-Zhabotinsky medium, strictly unable to autonomously initiate autowaves, is forced with a spatiotemporal patterned random illumination. These experimental observations are also reproduced numerically by using a set of reaction-diffusion equations for an activator-inhibitor model, and further analytically interpreted in terms of genuine coupling effects arising from parametric fluctuations. Within the same framework we also address situations of noise-sustained propagation in subexcitable media.

Spatiotemporal order out of noise

Experimental observations of self-organized behavior arising out of noise are also described, and details on the numerical algorithms needed in the computer simulation of these problems are given.

How to Reduce Tire-Pavement Noise: Better Practices for Constructing and Texturing Concrete Pavement Surfaces, TPF-5(139), 2012

Concrete pavements can be designed and constructed to be as quiet as any other conventional pavement type in use today. This report provides an overview of how this can be done—and done consistently. In order to construct a quieter concrete pavement, the texture must have certain fundamental characteristics. While innovative equipment and techniques have shown promise for constructing quieter pavements in the future, quieter concrete pavements are routinely built today all across the United States using the following standard nominal concrete pavement textures: drag, longitudinal tining, diamond grinding, and even, to limited extent, transverse tining. This document is intended to serve as a guide that describes better practices for designing, constructing, and texturing quieter concrete pavements.

Effectiveness of Parallel Noise Barriers - An Iowa Study, HR-540, 1987

Traffic noise monitoring using FHWA's Demonstration Projects Division Mobile Noise Laboratory at free field, single wall and parallel barrier site on I-380 in Evansdale, Iowa is described. Access to I-380 prior to its being open to traffic afforded a controlled pass-by monitoring phase involving different vehicle types. A subsequent second phase entailed identical measurement methodology to monitor "real world" I-380 traffic noise. Phase I data indicated increases in noise were significant under the parallel barrier conditions for light duty vehicles operating in the far lane. Phase II results showed that the actual I-380 traffic mix largely offset the earlier observed effect, but minor increases in traffic noise under the parallel system were noted. These differences in noise barrier system effectiveness are judged to be insignificant at this particular study location.