Premature termination in couple therapy with veterans: Definitions and prediction of long-term outcomes.

Premature termination (PT) has been identified as widespread in individual, family, and couple therapy. Unfortunately, research on PT utilizes numerous definitions of PT without providing guidance on which definition may be most clinically useful. The current study investigated seven definitions of PT (three based on therapist ratings and four based on quantitative measures) utilizing a sample of 177 couples seeking treatment at two Department of Veterans Affairs medical centers. Results indicated that PT occurred in 50–80% of couples; however, agreement between the definitions of PT was generally only in the slight to fair range, making it difficult to determine whether a particular couple was ready to terminate treatment. Additionally, many commonly used definitions of PT were unrelated to level or maintenance of relationship functioning following treatment. In contrast, two definitions of PT (ending treatment in the distressed range and therapist-rated likelihood of future unhappiness) significantly predicted larger decreases in relationship satisfaction during the 18 months following therapy, as well as lower levels of satisfaction and relationship stability 18 months after termination. Additionally, long-term relationship functioning was especially poor when both these definitions of PT were met, suggesting that both qualitative and quantitative definitions should inform decisions about termination in couple therapy. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The extinction of hydrocarbon flames based on the heat-absorption processes which occur in them

An empirical relation has been developed which correlates and predicts the fire-suppression effectiveness of a wide variety of gaseous, liquid and solid agents. The flame-extinguishment model is based on the premise that extinction is dominated by heat-absorption processes and that a flame is extinguished when sufficient heat has been removed by the extinguishant to reduce the temperature to a limit value. This limit value. This limit is the minimum temperature at which the effective rate of the combustion reactions is sufficient to maintain flamepropagation, and it depends in a predictable way on the properties of the suppressant and flame system. The heat-balance equation describing this is derived in two stages. In the first, a preliminary equation is obtained by considering only those substances which are thermally stable and act only as heat-capacity sinks. In the second, the equation is generalized by consideration of all endothermic reaction sinks, e.g. vaporization, dissociation and decomposition. The general equation correlates most of the extinction data found in the literature. The results suggest that for most substances the extinguishing capacity is related to heat-extraction data found in the literature. The results suggest that for most substances the extinguishing capacity is related to heat-extraction and that many of the effects previously attributed to chemical mechanisms may be thermodynamic in nature rather than kinetic.     

Adaptive optics with advanced phase-contrast techniques. II. High-resolution wave-front control

A wave-front control paradigm based on gradient-flow optimization is analyzed. In adaptive systems with gradient-flow dynamics, the output of the wave-front sensor is used to directly control high-resolution wavefront correctors without the need for wave-front phase reconstruction (direct-control systems). Here, adaptive direct-control systems with advanced phase-contrast wave-front sensors are analyzed theoretically, through numerical simulations, and experimentally. Adaptive system performance is studied for atmospheric-turbulence-induced phase distortions in the presence of input field intensity scintillations. The results demonstrate the effectiveness of this approach for high-resolution adaptive optics.     

Anisoplanatic imaging through turbulent media: image recovery by local information fusion from a set of short-exposure images

A wide-field-of-view white-light imaging experiment with artificially generated turbulence layers located between the extended object and the imaging system is described. Relocation of the turbulence sources along the imaging path allowed the creation of controllable anisoplanatic effects. We demonstrate that the recently proposed synthetic imaging technique [J. Opt. Soc. Am. A 16, 1623 (1999)] may result in substantial improvement in image quality for highly anisoplanatic conditions. It is shown that for multisource objects located at different distances the processing of turbulence-degraded short-exposure images may lead to a synthetic image that has an image quality superior to that of the undistorted image obtained in the absence of turbulence (turbulence-induced image quality enhancement).     

Modulation effects of epidural spinal cord stimulation on muscle activities during walking.

Epidural spinal cord stimulation (ESCS) combined with partial weight bearing therapy (PWBT) has been reported to facilitate recovery of functional walking for individuals after chronic incomplete spinal cord injury (ISCI). Muscle activities were analyzed in this report to examine the modulation effect of ESCS on muscle recruitment during gait training. Two ISCI individuals participated in the study and both are classified as ASIA C with low motor scores in the lower limbs. Stimulating electrodes were placed at the epidural space over T10-L2 spinal segments, along the midline in participant 1 (S1), and off-midline in participant 2 (S2). Surface electromyograms (EMGs) from leg muscles under both ESCS ON and OFF conditions recorded during treadmill gait were analyzed in time-frequency domains. ESCS application produced acute modulations in muscle activities in both participants, but the observed pattern, magnitude, and spectral content of the EMGs differed. In S1, ESCS induced a significant shift in the temporal pattern of muscle activity toward normal comparing with that when ESCS was OFF, though without eliciting noticeable change in frequency distribution between ESCS ON and OFF conditions. When ESCS was applied in S2, a modulation of EMG magnitude was observed and, consequently, improved joint kinematics during walking. In this case, a stimulation entrainment appeared in time-frequency analysis. The results suggest that ESCS activates neural structures in the dorsal aspect of the spinal cord and facilitates gait-related muscle recruitment. The exact effects of ESCS depend on the electrode placement and possibly injury history and residual functions, but in general ESCS produces a positive effect on improved walking speed, endurance, and reduced sense of effort in both ISCI subjects.     

Extinguishing Class A fires with multipurpose chemicals

We investigated the extinguishing properties of multipurpose dry chemicals using openregime cribs of two sizes. One measured 20.3 by 20.3 by 15.2 cm, and the other 50.8 by 50.8 by 38 cm. A crib fire, which has both flaming and smoldering contributions, is primarily extinguished when the burning surfaces are covered or smothered by a gas phase of the original multipurpose agent or a product of the agent's decomposition. The overall effectiveness of each dry chemical depends on its particle size, the degree of its decomposition and/or vaporization, and the openness of the crib. All particles of an agent below a unique limiting size completely decompose and/or vaporize in the crib fire and have the same extinguishing effectiveness. Particles above the limit have no measurable effectiveness. Scaling is considered on the basis of the minimum extinction weight per unit of exposed wood surface.Carhart is recently retired from the U.S. Navy Technology Center for Safety and Survivability at the Naval Research Laboratory in Washington, D.C.     

Adaptive wavefront control with asynchronous stochastic parallel gradient descent clusters

A scalable adaptive optics (AO) control system architecture composed of asynchronous control clusters based on the stochastic parallel gradient descent (SPGD) optimization technique is discussed. It is shown that subdivision of the control channels into asynchronous SPGD clusters improves the AO system performance by better utilizing individual and/or group characteristics of adaptive system components. Results of numerical simulations are presented for two different adaptive receiver systems based on asynchronous SPGD clusters-one with a single deformable mirror with Zernike response functions and a second with tip-tilt and segmented wavefront correctors. We also discuss adaptive wavefront control based on asynchronous parallel optimization of several local performance metrics-a control architecture referred to as distributed adaptive optics (DAO). Analysis of the DAO system architecture demonstrated the potential for significant increase of the adaptation process convergence rate that occurs due to partial decoupling of the system control clusters optimizing individual performance metrics.     

Epidural spinal-cord stimulation facilitates recovery of functional walking following incomplete spinal-cord injury

We investigated a novel treatment paradigm for developing functional ambulation in wheelchair-dependent individuals with chronic, incomplete spinal-cord injury. By coordinating epidural stimulation of the dorsal structures of the spinal cord with partial weight bearing treadmill therapy, we observed improvement in treadmill and over-ground ambulation in an individual with chronic incomplete tetraplegia. The application of partial weight-bearing therapy alone was not sufficient to achieve functional ambulation over ground, though treadmill ambulation improved significantly. Combining epidural spinal-cord stimulation (ESCS, T/sub 10/-T/sub 12/ vertebral levels) with partial weight-bearing therapy resulted in further improvement during treadmill ambulation. Moreover, the combination of therapies facilitated the transfer of the learned gait into over ground ambulation. Performance improvements were elicited by applying continuous, charge-balanced, monophasic pulse trains at a frequency of 40-60 Hz, a pulse duration of 800 /spl mu/s, and an amplitude determined by the midpoint (50%) between the sensory and motor threshold values. The participant initially reported a reduction in sense of effort for over ground walking from 8/10 to 3/10 (Borg scale), and was able to double his walking speed. After several weeks of over ground training, he reached maximum walking speeds of 0.35 m/s, and was able to ambulate over 325 m. We propose that ESCS facilitated locomotor recovery in this patient by augmenting the use-dependent plasticity created by partial weight bearing therapy. Confirmation of these promising results in a controlled study of groups of spinal-cord-injured subjects is warranted.     

Adaptive optics based on analog parallel stochastic optimization: analysis and experimental demonstration

Wave-front distortion compensation using direct system performance metric optimization is studied both theoretically and experimentally. It is shown how different requirements for wave-front control can be incorporated, and how information from different wave-front sensor types can be fused, within a generalized gradient descent optimization paradigm. In our experiments a very-large-scale integration (VLSI) system implementing a simultaneous perturbation stochastic approximation optimization algorithm was applied for real-time adaptive control of multielement wave-front correctors. The custom-chip controller is used in two adaptive laser beam focusing systems, one with a 127-element liquid-crystal phase modulator and the other with beam steering and 37-control channel micromachined deformable mirrors. The submillisecond response time of the micromachined deformable mirror and the parallel nature of the analog VLSI control architecture provide for high-speed adaptive compensation of dynamical phase aberrations of a laser beam under conditions of strong intensity scintillations. Experimental results demonstrate improvement of laser beam quality at the receiver plane in the spectral band up to 60 Hz.     

Evidence for flame extinguishment by thermal mechanisms

This paper presents an analysis of experimental flame and detonation extinguishment data published by a number of authors, including those in a companion paper. The maximum effectiveness observed for each of five common dry chemicals at small particle diameters is shown to be related to heat extraction from the flame by active endothermic sinks—heat capacity, fusion, vaporization, and decomposition. Larger particles are more stable in the flame and the reduced level of effectiveness observed is due principally to the only active sink—heat capacity.Evidence is presented to support two propositions: first, that the strong chemical inhibiting effects exhibited by many substances in flame velocity studies are effectively confined to low-concentration regimes; and second, that regardless of chemical effects, diffusion flames of the type studied are largely extinguished by thermal or heat extraction mechanisms at extinguishant concentrations that are quantitatively predicted by a simple heat balance and a predictable limit temperature.