Sonification supports eyes-free respiratory monitoring and task time-sharing

Three experiments explored the effectiveness of continuous auditory displays, or sonifications, for conveying information about a simulated anesthetized patient's respiration. Experiment 1 established an effective respiratory sonification. Experiment 2 showed an effect of expertise in the use of respiratory sonification and revealed that some apparent differences in sonification effectiveness could be accounted for by response bias. Experiment 3 showed that sonification helps anesthesiologists to maintain high levels of awareness of the simulated patient's state while performing other tasks more effectively than when relying upon visual monitoring of the simulated patient state. Overall, sonification of patient physiology beyond traditional pulse oximetry appears to be a viable and useful adjunct to visual monitors. Actual and potential applications of this research include monitoring in a wide variety of busy critical care contexts.     

Fetal MEG redistribution by projection operators

The fetal magnetoencephalogram (fMEG) is measured in the presence of large interference from the maternal and fetal magnetocardiograms. This interference can be efficiently attenuated by orthogonal projection of the corresponding spatial vectors. However, the projection operators redistribute the fMEG signal among sensors. Although redistribution can be readily accounted for in the forward solution, visual interpretation of the fMEG signal topography is made difficult. We have devised a general, model-independent method for correction of the redistribution effect that utilizes the assumption that we know in which channels the fMEG should be negligible (such channels are distant from the known fetal head position). In a simplified case where the fMEG can be explained by equivalent current dipoles, the correction can also be obtained from fitting the dipoles to the fMEG signal. The corrected fMEG signal topography then corresponds to the dipole forward solution, but without orthogonal projection. We illustrate the redistribution correction on an example of experimentally measured flash evoked fMEG.     

An interior-point sequential approximate optimization methodology

The use of optimization in a simulation-based design environment has become a common trend in industry today. Computer simulation tools are commonplace in many engineering disciplines, providing the designers with tools to evaluate a designs performance without building a physical prototype. This has triggered the development of optimization techniques suitable for dealing with such simulations. One of these approaches is known as sequential approximate optimization. In sequential approximate minimization a sequence of optimizations are performed over local response surface approximations of the system. This paper details the development of an interior-point approach for trust-region-managed sequential approximate optimization. The interior-point approach will ensure that approximate feasibility is maintained throughout the optimization process. This facilitates the delivery of a usable design at each iteration when subject to reduced design cycle time constraints. In order to deal with infeasible starting points, homotopy methods are used to relax constraints and push designs toward feasibility. Results of application studies are presented, illustrating the applicability of the proposed algorithm.     

Combat experience and youth: Influences on reported violence against women.

A study of 101 VA psychiatric and chemically dependent inpatients (mean age 44.8 yrs) was conducted to investigate the hypothesis that combat veterans (n?=?54) would report a higher frequency of physical violence against female partners than noncombat veterans (n?=?47). Veterans were interviewed by staff psychologists seeking information about the frequency and severity of violence toward their female partners and about whether or not they had been in combat. Results show no significant differences in reported violence toward female partners between the combat and noncombat veterans even when age was controlled. Younger men were, however, more violent toward women than older men. Data cast doubt on the view that combat experience leads to violence within marital relationships. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Location of stable and unstable equilibrium configurations using a model trust region quasi-Newton method and tunnelling

A hybrid method for locating multipole equilibrium configurations has been proposed recently. The hybrid method combined the efficiency of a quasi-Newton method capable of locating stable and unstable equilibrium solutions with a robust homotopy method capable of tracking equilibrium paths with turning points and exploiting sparsity of the Jacobian matrix at the same time. A quasi-Newton method in conjunction with a deflation technique is proposed here as an alternative to the hybrid method. The proposed method not only exploits sparsity and symmetry, but also represents an improvement in efficiency.     

Modeling kinetic processes controlling hydrogen and acetate concentrations in an aquifer-derived microcosm

Groundwater contaminants may degrade via fermentation to intermediate species, which are subsequently consumed by terminal electron-accepting processes (TEAPs). A numerical model of an aquifer-derived laboratory microcosm is developed to simulate the dynamic behavior of fermentation and respiration in groundwater by coupling microbial growth and substrate utilization kinetics with a formulation that also includes aqueous speciation and other geochemical reactions including surface complexation, mineral dissolution, and precipitation. The model is used to test approaches that currently make use of H2(aq) to diagnose prevalent TEAPs in groundwater. Competition between TEAPs is integral to the conceptual model of the simulation, and the results indicate that competitive exclusion is significant but with some overlap found in the temporal sequence of TEAPs. Steady-state H2(aq) concentrations observed during different TEAPs do not differ significantly. The results are not consistent with previous applications of the partial equilibrium approach since most TEAP redox pairs exhibit free energies that suggest a particular process is able to proceed, yet observations here show that this process does not proceed.     

Yielding of the clamped-wire system in the Ilizarov external fixator

This study demonstrates that the clamped-wire system used to suspend bones within an Ilizarov external fixator yields when the perpendicular load exceeds 50 N per wire. Cyclic loading was applied to tensioned wires clamped within an Ilizarov ring component, with steadily increasing load amplitude. Wires were tested at four initial tension settings. The amount of energy lost within the clamped-wire system per load cycle was calculated for every test. The results showed that there was a consistent trend to increasing non-recoverable energy loss per load cycle when peak loads exceed 50 N for all initial tension settings. A finite element (FE) model replicating the experimental conditions was performed to investigate the levels of stress within the loaded wires. The FE model analyses showed that high stresses were generated in the wires close to the clamping sites, and that the stress levels could reasonably be expected to exceed the material yield stress when loaded to about 55 N, for all initial tension settings. The results show that material yield, accompanied by some wire slippage through the clamps, is responsible for system yield, in agreement with previous studies. Although the initial wire tension has an appreciable effect on the wire stiffness, it did not affect the elastic load range of the clamped-wire system. To prevent yield of the clamped-wire system in practice, the fixator should be assembled with sufficient wires to ensure that the load transmitted to each wire by the patient does not exceed 50 N.     

Zero Sound Attenuation Near the Quantum Limit in Normal Liquid 3He Close to the Superfluid Transition

The zero sound attenuation of normal liquid ³He has been studied over a range of temperatures from slightly above the superfluid transition temperature, T _c, to approximately 10mK at the constant pressures of 1 and 5bar. Using longitudinal LiNbO₃ transducers, operating both on and off resonance, the experiment was performed at 15 discrete frequencies located in several broadband frequency windows, including 16–25, 60–70, and 105–111MHz. The results are compared to Landau's prediction for the attenuation of zero sound in the quantum limit, (k _B Tk _B T _F), where ₀(P,T, )= (P) T ²{1+(/2k _B T)²}. Calibration of the received zero sound signals was performed by measuring the temperature dependence of the first sound attenuation from 30 to 800mK at those same frequencies and pressures. The data are compared to previous results.