The reliability of a 10-test package for patients with prolonged back and neck pain: could an examiner without formal medical education be used without loss of quality? A methodological study

BACKGROUND: In the rehabilitation of patients with prolonged back and neck pain, the physical impairment should be assessed. Previous research has exclusively engaged medically educated examiners, mostly physiotherapists. However, less biased evaluations of efforts at rehabilitation might be achieved by personnel standing outside the treatment work itself. Therefore, if medically untrained examiners could be used without cost to the quality, this might produce a better evaluation at defensible cost and could also be useful in a research context. The aim of this study was to answer the question: given a 10-test package for patients with prolonged back and neck pain, could an examiner without formal medical education be used without loss of quality? Five of the ten tests required the examiner to keep a firm hold against the foundation of those parts of the participant's body that were not supposed to move during the test. METHODS: Examination by an experienced physiotherapist (A) in performing the package was compared with that by a research assistant (B) without formal medical education. The reliability, including inter- and intra-rater reliability, was assessed. In the inter-rater reliability study, 50 participants (30 patients + 20 healthy subjects) were tested once each by A and B. In the intra-rater reliability study, the 20 healthy subjects were tested twice by A or B. One-way ANOVA intra-class-correlation coefficient (ICC) was calculated and its possible systematic error was determined using a t-test. RESULTS: All five tests that required no manual fixation had acceptable reliability (ICC > .60 and no indication of systematic error). Only one of the five tests that required fixation had acceptable reliability. The difference (five vs. one) was significant (p = .01). CONCLUSION: In a 10-test package for patients with prolonged back and neck pain, an examiner without formal medical education could be used without loss of quality, at least for the five tests requiring no manual fixation. To make our results more generalizable and their implications more searching, a similar study should be conducted with two or more examiners with and without formal medical education, and the intra-rater reliability study should also include patients and involve more participants

Supersonic Jet Excitation using Flapping Injection

Supersonic jet noise reduction is important for high speed military aircraft. Lower acoustic levels would reduce structural fatigue leading to longer lifetime of the jet aircraft. It is not solely structural aspects which are of importance, health issues of the pilot and the airfield per- sonnel are also very important, as high acoustic levels may result in severe hearing damage. It remains a major challenge to reduce the overall noise levels of the aircraft, where the supersonic exhaust is the main noise source for near ground operation. Fluidic injection into the supersonic jet at the nozzle exhaust has been shown as a promising method for noise reduction. It has been shown to speed up the mix- ing process of the main jet, hence reducing the kinetic energy level of the jet and the power of the total acoustic radiation. Furthermore, the interaction mechanism between the fluidic injection and the shock structure in the jet exhaust plays a crucial role in the total noise radia- tion. In this study, LES is used to investigate the change in flow struc- tures of a supersonic (M=1.56) jet from a converging-diverging nozzle. Six fluidic actuators, evenly distributed around the nozzle exit, inject air in a radial direction towards the main flow axis with a total mass flow ratio of 3%. Steady injection is compared with flapping injection. With flapping injection turned on, the injection angle of each injector is varied sinusoidally in the nozzle exit plane and the variation is the same for all injectors. This fluid dynamics video is submitted to the APS DFD Gallery of Fluid Motion 2013 at the 66 the Annual Meeting of the American Physical Society, Division of Fluid Dynamics (24-26 November, Pittsburgh, PA, USA).Comment: 3 pages, 2 linked animations/video

Evaluation of Optimized 3-step Global Reaction Mechanism for CFD Simulations on Sandia Flame D

The aim of this paper is to evaluate a new optimized 3-step global reaction mechanism (opt) [1] for a methane-air mixture for industry purpose. The global reaction mechanism consists of three reactions corresponding to the fuel oxidation into CO and H2O, and the CO–CO2 equilibrium reaction. Correction functions that are dependent on the local equivalence ratio are introduced into the global mechanism. The optimized 3-step global reaction scheme is adapted into the Computational Fluid Dynamics (CFD) analysis of a partially-premixed piloted methane jet flame. The burner consists of a central nozzle (for premixed fuel/air), surrounded by a premixed pilot flame, and an annular co-flow stream. Both steady-state RANS (Reynolds Averaged Navier Stokes) and time-averaged hybrid URANS/LES (Unsteady RANS/Large Eddy Simulation) results have been computed and compared with experimental results obtained from the Sydney burner at Sandia National Laboratories, Sandia Flame D [2]. The CFD results with the optimized 3-step global reaction mechanism show reasonable agreement with the experimental data based on emission, velocity and temperature profiles, while the 2-step Westbrook Dryer (WD2) [3] global reaction mechanism shows poor agreement with the emission profiles. ©2011 American Institute of Physic

Nonlinear Rotor Wake/Stator Interaction Computations

Rotor wake interactions with stators is an important aspect in turbomachinery noise generation. This paper deals with the time lagged periodic boundary condition (chorochronic periodicity) used in time domain Navier-Stokes equations solvers. The time lag periodic b.c. is used to solve the nonlinear three dimensional N-S equations using realizable k-epsilon turbulence model and time dependent wake defined at the inlet, with only a limited number of blade passages discretized. The time lag periodic b.c. has been validated through a number of 3D test cases. It has been shown that the use of a periodic/temporal damping term is an efficient way to stabilize the time lagged boundary condition without adding any extra spatial dissipation to the computation. The acoustic response from a stator vane with wakes defined at the inlet is presented

Influence of gas compression on flame acceleration in the early stage of burning in tubes

The mechanism of finger flame acceleration at the early stage of burning in tubes was studied experimentally by Clanet and Searby [Combust. Flame 105: 225 (1996)] for slow propane-air flames, and elucidated analytically and computationally by Bychkov et al. [Combust. Flame 150: 263 (2007)] in the limit of incompressible flow. We have now analytically, experimentally and computationally studied the finger flame acceleration for fast burning flames, when the gas compressibility assumes an important role. Specifically, we have first developed a theory through small Mach number expansion up to the first-order terms, demonstrating that gas compression reduces the acceleration rate and the maximum flame tip velocity, and thereby moderates the finger flame acceleration noticeably. This is an important quantitative correction to previous theoretical analysis. We have also conducted experiments for hydrogen-oxygen mixtures with considerable initial values of the Mach number, showing finger flame acceleration with the acceleration rate much smaller than those obtained previously for hydrocarbon flames. Furthermore, we have performed numerical simulations for a wide range of initial laminar flame velocities, with the results substantiating the experiments. It is shown that the theory is in good quantitative agreement with numerical simulations for small gas compression (small initial flame velocities). Similar to previous works, the numerical simulation shows that finger flame acceleration is followed by the formation of the "tulip" flame, which indicates termination of the early acceleration process.Comment: 19 pages, 20 figure

Serotonin Depletion-Induced Maladaptive Aggression Requires the Presence of Androgens

The sex hormone testosterone and the neurotransmitter serotonin exert opposite effects on several aspects of behavior including territorial aggression. It is however not settled if testosterone exerts its pro-aggressive effects by reducing serotonin transmission and/or if the anti-aggressive effect of serotonin requires the presence of the androgen. Using the resident intruder test, we now show that administration of the serotonin synthesis inhibitor parachlorophenylalanine (300 mg/kg x 3 days) increases the total time of attack as well as the percentage amount of social behavior spent on attack but not that spent on threat - i.e. that it induces a pattern of unrestricted, maladaptive aggression - in gonadectomized C57Bl/6 male mice receiving testosterone replacement; in contrast, it failed to reinstate aggression in those not given testosterone. Whereas these results suggest the pro-aggressive effect of testosterone to be independent of serotonin, and not caused by an inhibition of serotonergic activity, the pCPA-induced induction of maladaptive aggression appears to require the presence of the hormone. In line with these findings, pCPA enhanced the total time of attack as well the relative time spent on attacks but not threats also in wild-type gonadally intact male C57Bl/6 mice, but failed to reinstate aggression in mice rendered hypo-aggressive by early knock-out of androgen receptors in the brain (AR(NesDel) mice). We conclude that androgenic deficiency does not dampen aggression by unleashing an anti-aggressive serotonergic influence; instead serotonin seems to modulate aggressive behavior by exerting a parallel-coupled inhibitory role on androgen-driven aggression, which is irrelevant in the absence of the hormone, and the arresting of which leads to enhanced maladaptive aggression

A Realistic Simulation Testbed of A Turbocharged Spark-Ignited Engine System: A Platform for the Evaluation of Fault Diagnosis Algorithms and Strategies

Research on fault diagnosis on highly nonlinear dynamic systems such as the engine of a vehicle have garnered huge interest in recent years, especially with the automotive industry heading towards self-driving technologies. This article presents a novel opensource simulation testbed of a turbocharged spark ignited (TCSI) petrol engine system for testing and evaluation of residuals generation and fault diagnosis methods. Designed and developed using Matlab/Simulink, the user interacts with the testbed using a GUI interface, where the engine can be realistically simulated using industrial-standard driving cycles such as the Worldwide harmonized Light vehicles Test Procedures (WLTP), the New European Driving Cycle (NEDC), the Extra-Urban Driving Cycle (EUDC), and EPA Federal Test Procedure (FTP-75). The engine is modeled using the mean value engine model (MVEM) and is controlled using a proportional-integral (PI)-based boost controller. The GUI interface also allows the user to induce one of the 11 faults of interest, so that their effects on the performance of the engine are better understood. This minimizes the risk of causing permanent damages to the engine and shortening its lifespan, should the tests be conducted onto the actual physical system. This simulation testbed will serve 16 as an excellent platform where researchers can generate critical data to develop and compare current and future research methods for fault diagnosis of automotive engine systems.Comment: 64 pages, 23 figures, To appear in IEEE Control System

Analysis of flame acceleration induced by wall friction in open tubes

Spontaneous flame acceleration leading to explosion triggering in open tubes/channels due to wall friction was analytically and computationally studied. It was first demonstrated that the acceleration is affected when the thermal expansion across the flame exceeds a critical value depending on the combustion configuration. For the axisymmetric flame propagation in cylindrical tubes with both ends open, a theory of the initial (exponential) stage of flame acceleration in the quasi-isobaric limit was developed and substantiated by extensive numerical simulation of the hydrodynamics and combustion with an Arrhenius reaction. The dynamics of the flame shape, velocity, and acceleration rate, as well as the velocity profile ahead and behind the flame, have been determined. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3425646