Initial Rate Of Change Research Articles

Audio fade profile customizing by imposing the audio volume initial rate of change

By adopting a rational function of degree 1, with the playback position in the course of an audio fade transition as the function input, and the audio volume as the function output, we advance a technique of setting up the audio fade profile by bringing forward a shape parameter that is directly proportional to the initial rate of change of the audio volume. We provide the relationships that are essential for computing the coefficients of the adopted rational function having at hand the audio effect characteristics, i.e. the fade length, initial volume, final volume and the parameter used for shaping. The versatility of the proposed technique is revealed by the numerous curves illustrating fade in, fade up, fade out and fade down transitions. The shape parameter is of key significance here having in view that it decides the pattern to follow. More precisely, one can set the value of the shape parameter in order to get either a fade effect that acts similar to the exponential shape fade or a fade effect that follows the pattern of the logarithmic shape fade. With a view to real time experimentation, a practical application, developed via plain JavaScript, is provided in the paper.

The impact of von Willebrand factor on fibrin formation and structure unveiled with type 3 von Willebrand disease plasma.

Normally, von Willebrand factor (VWF) remains inactive unless its A1A2 domains undergo a shear stress-triggered conformational change. We demonstrated the capacity of a recombinant A2 domain of VWF to bind and to affect fibrin formation, altering the fibrin clot structure. The data indicated that VWF contains an additional binding site for fibrin in the A2 domain that plays a role in the incorporation of VWF to the polymerizing fibrin. This study is to examine the hypothesis that active plasma VWF directly influence fibrin polymerization and the structure of fibrin clots. The study used healthy and type 3 von Willebrand disease (VWD) plasma, purified plasma VWF, fibrin polymerization assays, confocal microscopy and scanning electron microscopy. The exposed A2 domain in active VWF harbors additional binding sites for fibrinogen, and significantly potentiates fibrin formation (P < 0.02). Antibody against the A2 domain of VWF significantly decreased the initial rate of change of fibrin formation (P < 0.002). Clot analyses revealed a significant difference in porosity between normal and type 3 VWD plasma (P < 0.008), further supported by scanning electron microscopy, which demonstrated thicker fibrin fibers in the presence of plasma VWF (P < 0.0003). Confocal immunofluorescence microscopy showed punctate VWF staining along fibrin fibrils, providing visual evidence of the integration of plasma VWF into the fibrin matrix. The study with type 3 VWD plasma supports the hypothesis that plasma VWF directly influences fibrin polymerization and clot structure. In addition, a conformational change in the A1A2 domains exposes a hidden fibrin(ogen) binding site, indicating that plasma VWF determines the fibrin clot structure.

Adaptive Temporary Frequency Support for DFIG-Based Wind Turbines

For a doubly-fed induction generator (DFIG)-based wind turbine (WT), the temporary frequency support (TFS) is a cost-effective strategy to achieve the system frequency regulation capability. However, there is no coupling relationship between the power increment and the system frequency in the existing TFS strategies, which limits the frequency support capability of WTs and even deteriorates the system frequency. To cope with it, this paper analyzes the adaptability of two representative TFS strategies under different load disturbance scenarios, and proposes some design guidelines for the power trajectory. Subsequently, an adaptive temporary frequency support (ATFS) strategy is proposed to improve the frequency stability when faced with different load disturbances. In the method, the initial power reference varies with the initial rate of change of frequency, and the power reference is reduced along the upward parabola and semicircle in the frequency support stage and rotor speed recovery stage, respectively. Furthermore, the ATFS strategy can improve the frequency nadir adaptively while well balancing the secondary frequency dip (SFD) and the speed recovery in different scenarios. Finally, the ATFS strategy is verified by hardware-in-loop (HIL) simulations.

Progressive Visual Field Loss and Subsequent Quality of Life Outcomes in Glaucoma

To evaluate the association between baseline severity of visual field (VF) damage and the initial rates of VF progression with quality of life (QOL) outcomes over an extended follow-up in glaucoma. Retrospective cohort study. Both eyes of 167 glaucoma or suspected glaucoma patients were followed for 10.0±0.3 years. The National Eye Institute Visual Function Questionnaire (NEI-VFQ)-25 was performed at the end of the follow-up. Separate linear regression models included the VF parameters of the better eye, the worse eye, and the central and peripheral points of the integrated binocular VF to evaluate the association of baseline and initial rates of change of VF parameters (first half of the follow-up) with NEI-VFQ-25 Rasch-calibrated disability scores over an extended follow-up. All models demonstrated association of worse baseline severity of VF damage with worse subsequent NEI-VFQ-25 scores. Faster rates of decline in VF mean deviation of the better eye and the mean sensitivity of the central and peripheral test locations of the integrated binocular VF were significantly associated with worse subsequent NEI-VFQ-25 scores. VF parameters of the better eye performed better than those of the worse eye (R2 of 0.21, and 0.15, respectively), and the VF parameters of the central test locations performed better than those of the peripheral test locations (R2 of 0.25, and 0.20, respectively). Baseline severity and initial rates of change of VF damage are associated with QOL outcomes over an extended follow-up. Assessment of longitudinal VF changes, especially in better eye, provides prognostic utility to identify glaucoma patients at a higher risk for developing disease-related disability.

Swing equation modelling of GFL inverter and comparison of its damping and inertia with GFM inverter

The increasing integration of inverter-based renewable generation into the network as Grid-Following inverters (GFL), combined with the reduction in traditional Synchronous Generation (SG) leads to a reduction in inertia and to instabilities. To alleviate this, researchers have proposed using a mix of GFL and Grid-Forming controllers (GFM). However, there is a lack of simple system-wide analytical models. This paper proposes a swing equation to describe the transient frequency response of GFL that has droop regulation of real and reactive power. The swing equation for GFL with droop has an inertia and a damping term as do SG and GFM swing equations. Simulations show that the use of swing equations for GFM and GFL is accurate to study the transient frequency stability following a loss of infeed. GFM and GFL damping are equivalent, and their sum allows prediction of frequency deviation. However, although SG and GFM inertia terms limit the initial Rate of Change of Frequency (RoCoF), the GFL inertia term is found not to contribute towards limitation of the initial RoCoF. Instead, the GFL RoCoF is seen to follow adjacent GFM RoCoF and worsens slightly when the GFL Phase Locked Loop (PLL) bandwidth is reduced.

CALCULATION OF A TRAJECTORY FOR THE MOVEMENT OF A LOAD OF SWINGING SPRING

Pendulum oscillations in the vertical plane of a suspended weightless spring, while maintaining the straightness of its axis, are considered. In the literature, this type of pendulum is called a swinging spring. The required trajectory of the load of the swinging spring is modeled using a computer using the values ​​of the mass of the load, the stiffness of the spring and its length without load. In addition, the initial values ​​of the parameters for initiating oscillations of the oscillating spring are used: the initial angle of deviation of the spring axis from the vertical, the initial rate of change of this angle, as well as the initial parameter of the spring elongation and the initial rate of change of the elongation. The calculations were performed using the Lagrange equation of the second kind. Variants of finding conditionally periodic trajectories of movement of a point load of a swinging spring with a movable attachment point are considered.&#x0D; The relevance of the topic is determined by the need to research and improve new technological schemes of mechanical devices, which include springs. In particular, the study of the conditions for separating from chaotic vibrations of mechanical structure elements and determining the rational values ​​of parameters to ensure periodic trajectories of their vibrations.&#x0D; Calculation options are given to obtain periodic trajectories of cargo movement, when the given parameters are:&#x0D; - the length of the spring without load and its stiffness with an unknown value of the mass of the load;&#x0D; - the length of the spring without load and the value of the mass of the load with an unknown spring stiffness;&#x0D; - the value of the mass of the load and the stiffness of the spring with an unknown length of the spring without load.&#x0D; The results can be used as a paradigm for studying nonlinear coupled systems, as well as for calculating options for mechanical devices, when it is necessary to dissociate themselves from chaotic movements of loads, and provide periodic trajectories of their movement.

Detection of emerging neurodegeneration using Bayesian linear mixed-effect modeling

Early detection of neurodegeneration, and prediction of when neurodegenerative diseases will lead to symptoms, are critical for developing and initiating disease modifying treatments for these disorders. While each neurodegenerative disease has a typical pattern of early changes in the brain, these disorders are heterogeneous, and early manifestations can vary greatly across people. Methods for detecting emerging neurodegeneration in any part of the brain are therefore needed. Prior publications have described the use of Bayesian linear mixed-effects (BLME) modeling for characterizing the trajectory of change across the brain in healthy controls and patients with neurodegenerative disease. Here, we use an extension of such a model to detect emerging neurodegeneration in cognitively healthy individuals at risk for dementia. We use BLME to quantify individualized rates of volume loss across the cerebral cortex from the first two MRIs in each person and then extend the BLME model to predict future values for each voxel. We then compare observed values at subsequent time points with the values that were expected from the initial rates of change and identify voxels that are lower than the expected values, indicating accelerated volume loss and neurodegeneration. We apply the model to longitudinal imaging data from cognitively normal participants in the Alzheimer’s Disease Neuroimaging Initiative (ADNI), some of whom subsequently developed dementia, and two cognitively normal cases who developed pathology-proven frontotemporal lobar degeneration (FTLD). These analyses identified regions of accelerated volume loss prior to or accompanying the earliest symptoms, and expanding across the brain over time, in all cases. The changes were detected in regions that are typical for the likely diseases affecting each patient, including medial temporal regions in patients at risk for Alzheimer’s disease, and insular, frontal, and/or anterior/inferior temporal regions in patients with likely or proven FTLD. In the cases where detailed histories were available, the first regions identified were consistent with early symptoms. Furthermore, survival analysis in the ADNI cases demonstrated that the rate of spread of accelerated volume loss across the brain was a statistically significant predictor of time to conversion to dementia. This method for detection of neurodegeneration is a potentially promising approach for identifying early changes due to a variety of diseases, without prior assumptions about what regions are most likely to be affected first in an individual.

Grid-Following Mode Operation of Small-Scale Distributed Battery Energy Storages for Fast Frequency Regulation in a Mixed-Source Microgrid

As the share of power converter-based renewable energy sources (RESs) is high, a microgrid, in islanded mode, is more vulnerable to frequency instability due to (1) sudden power imbalance and (2) low inertia. One of the most common approaches to address this issue is to provide virtual inertia to the system by appropriately controlling the grid-side converter of the RESs. However, the primary frequency controller (PFC) presented in this paper focuses on the fast compensation of power imbalance without adding inertia to the system. The proposed method is based on estimating the real-time power imbalance caused by a disturbance and compensating it using multiple small-scale distributed battery energy storage systems (BESSs). The power imbalance is estimated by observing the initial rate of change of frequency (RoCoF) following a disturbance. Based on the estimated power imbalance and the rating of the BESSs, the reference power for the BESSs is determined. The BESSs are controlled in grid-following mode to compensate for the power imbalance. The performance of the proposed PFC is verified using a Typhoon real-time simulator for various scenarios and is compared with the conventional virtual synchronous generator (VSG) controller.

Novel Coordinated Control Strategy of BESS and PMSG-WTG for Fast Frequency Response

An increase in inverter-based resources (IBRs) can lower the inertia of a power system, which may adversely affect the power system by causing changes such as a frequency nadir reduction or an increased initial rate of change of frequency (RoCoF). To prevent this, an ancillary service called fast frequency response (FFR) helps the inertia response by using IBRs. The main resources used in FFR are variable-speed wind turbine generators (VSWTGs) or energy storage systems (ESSs), which can respond quickly through converter control. The control is applied to the frequency regulation service faster than the primary frequency response, so the second frequency nadir may fall below the first frequency nadir. This study proposed a novel coordinated control strategy to efficiently utilize energy to improve the frequency nadir through coordinated control of wind turbines based on permanent magnetic synchronous generators (PMSGs) and battery energy storage systems (BESSs). The simulation results confirmed that the two-bus test system was composed of PSCAD/EMTDC, and the frequency nadir increased by utilizing the same amount of energy as in traditional control systems.

Thermodynamic modeling and new experimental CO2 solubility into aqueous EAE and AEEA blend, heat of absorption, cyclic absorption capacity and desorption study for post-combustion CO2 capture

In the present study, carbon dioxide (CO2) solubility into aqueous blend of 2-(ethylamino) ethanol (EAE) and aminoehtylethanolamine (AEEA) was measured. The performance of CO2 capture by this amine blend was investigated in terms of CO2 solubility, heat of absorption, cyclic CO2 solubility, and initial rate of change of CO2 solubility. CO2 absorption study was carried out using bubble column reactor in the temperature range of 298.15 to 323.15 K, 8.11 to 20.27 kPa CO2 partial pressure, 0.10 to 0.30 wt fraction of AEEA in EAE and AEEA blend, and 10 to 30 wt% total concentration of blend solution. Desorption experiments were performed at 393.15 K. Maximum CO2 solubility was 1.033 mol CO2/mol amine at 298.15 K, 20.27 kPa, 0.30 wt fraction of AEEA in the blend, and 10 wt% of EAE and AEEA solution. A semi-empirical Kent-Eisenberg thermodynamic model and an empirical model were developed to calculate equilibrium CO2 solubility in the studied range of operating conditions with 2.56% and 0.45% average absolute deviation, respectively. At 313.15 K, 15.20 kPa CO2 partial pressure and total concentration of 30 wt% of EAE and AEEA blend, the equilibrium CO2 solubility was resulted as 0.748 mol CO2/mol amine and cyclic solubility of 0.503 mol CO2/mol amine was achieved. Heat of CO2 absorption was measured based on Gibbs Helmholtz equation and found as −72.25 kJ/mol for 30 wt% aqueous EAE and AEEA blend. Results of absorption capacity of EAE and AEEA solution and monoethylethanolamine (MEA) were compared at same operating conditions. This blend had higher CO2 solubility, lesser heat of absorption, more cyclic capacity and faster rate of change of initial CO2 solubility than MEA.

The distinct roles of initial transmission and retransmission in the persistence of knowledge in complex networks

The rate of successfully acquiring knowledge depends on whether the individual has previously held that knowledge. In an earlier work, we represented this phenomenon by dividing the dynamical process of knowledge transmission into initial and retransmission stages, and applied mean field theory to identify an approximate condition for knowledge survival on homogeneous networks. In this work we move beyond our earlier, approximate results for homogeneous networks to provide rigorous results applicable to complex networks of arbitrary topology - including heterogeneous real world social networks. Specifically, we extend the Intertwined Continuous Markov Chain (ICMC) and Probabilistic Discrete Markov Chain (PDMC) models to address the Naive-Evangelical-Agnostic-Evangelical (VEAE) knowledge transmission process in complex networks. We identify the corresponding basic reproduction number R0, the quantity which dictates whether or not knowledge survives, and deduce simple upper and lower bounds for this measure. Moreover, simulations are performed to verify both the theoretical results, and the mutual consistency of the ICMC, PDMC and Monte Carlo methods. The simulations demonstrate that the initial transmission process directly affects the initial rate of change of the number of evangelical individuals, but has no effect on evangelical density in the steady state. However, the retransmission process has a direct effect on the steady state density of evangelical individuals.

Fast frequency response of inverter-based resources and its impact on system frequency characteristics

The inertia response and primary frequency regulation capability of synchronous grids are declining owing to the increasing penetration of inverter-based resources. The fast frequency response (FFR) of inverter-based resources is an important mitigation option for maintaining grid security under the conditions of low inertia and insufficient primary frequency response capability. However, the understanding and technical characteristics of the FFR of inverter-based resources are still unclear. Aiming at solving the aforementioned problems, this paper proposes a definition for FFR based on the impact mechanism of FFR on system frequency. The performance requirements of FFR are clarified. Then, the effects of FFR on system frequency characteristics are further analyzed based on steady-state frequency deviation, the initial rate of change of frequency, and the maximum transient frequency deviation. Finally, the system requirements for FFR and its application effects are verified by simulating an actual bulk power grid, providing technical support for subsequent engineering application.

Soil carbon market-based instrument pilot – the sequestration of soil organic carbon for the purpose of obtaining carbon credits

Increasing soil organic carbon (SOC) in Australian farming systems has the potential to offset greenhouse gas emissions. Even though methods for soil carbon (C) sequestration have been developed under the Australian Government’s Emissions Reduction Fund, the scope for farm-scale soil C sequestration is poorly understood. A pilot scheme was developed in Central West New South Wales to trial the use of a market-based instrument to encourage farmers to change farm management to increase SOC. This paper reports changes to SOC stocks measured on farms that were successfully contracted in the pilot. The 10 contracted farms were those that submitted the lowest bid per Mg CO2-e. Four land uses were contracted in the pilot: (1) reduced tillage cropping (reference); (2) reduced tillage cropping with organic amendments (e.g. biosolids or compost); (3) conversion from cropping land to permanent pasture; and (4) conversion from cropping land to permanent pasture with organic amendments. At each site a minimum of 10 locations (sampling points) were sampled and analysed for total carbon (LECO elemental analyser) and bulk density calculated. The SOC stocks (0–0.3 m) were assessed before (2012) and after the pilot (2017; calculated on equivalent soil mass of 2012), with 60% of sites showing a significant increase. Pasture had a higher rate of SOC sequestration than reduced tillage cropping (1.2 vs 0.28 Mg C ha–1 year–1, 0–0.3 m); and organic amendments had higher rates of SOC sequestration than without (1.14 vs 0.78 Mg C ha–1 year–1, 0–0.3 m). The results of the pilot demonstrated increases in SOC, using quantification methods consistent with the current Measurement Method of the Australian Government’s Emissions Reduction Fund policy used to generate Australian Carbon Credit Units. The results require careful interpretation as rates of sequestration are likely to be lower in the longer term than initial rates of change seen in this pilot (five years), and the pilot intentionally selected sites with initially low SOC, which ensured a greater opportunity to sequester SOC.

Modulating the rate of fibrin formation and clot structure attenuates microvascular thrombosis in systemic inflammation

Systemic inflammation can lead to coagulopathy and disseminated intravascular coagulation (DIC). In prior studies, the recombinant A2 domain of human von Willebrand factor (VWF; A2 protein) attenuated DIC and decreased mortality in lipopolysaccharide (LPS)-treated mice. Here, we performed studies to dissect the mechanism by which the A2 protein moderates DIC. We used confocal microscopy to analyze the fibrin clot structure in plasma from healthy humans and endotoxemic mice, turbidity assays to examine fibrin polymerization, and a murine model for LPS-induced DIC and introduced a loss-of-function mutation into the A2 protein for fibrin. The mutation of the residue E1567 located in the α2 helix of the folded A2 domain of VWF inhibited binding activity for fibrin, possibly mapping a novel region containing a putative binding site for fibrin. The A2 protein increased the initial rate of change of fibrin polymerization, intercalated into the fibrin network, and modified the resultant clot structure in vitro. Furthermore, ex vivo experiments using plasma from mice with endotoxemia treated with the A2 protein revealed an increased rate of fibrin formation and an altered clot structure as compared with plasma from nontreated sick animals. Moreover, and in contrast to the A2 mutant, the A2 protein improved survival and reduced fibrin deposition and microvascular thrombosis in mice with endotoxemia-induced DIC. Importantly, in vivo and in vitro studies indicated that the A2 protein did not affect experimental thrombosis. Thus, we provide evidence for a novel treatment to attenuate systemic inflammation-induced coagulopathy/DIC via targeting fibrin formation, without an increased risk for bleeding.

Activity of two key toxin groups in Australian elapid venoms show a strong correlation to phylogeny but not to diet

BackgroundThe relative influence of diet and phylogeny on snake venom activity is a poorly understood aspect of snake venom evolution. We measured the activity of two enzyme toxin groups – phospholipase A2 (PLA2), and L-amino acid oxidase (LAAO) – in the venom of 39 species of Australian elapids (40% of terrestrial species diversity) and used linear parsimony and BayesTraits to investigate any correlation between enzyme activity and phylogeny or diet.ResultsPLA2 activity ranged from 0 to 481 nmol/min/mg of venom, and LAAO activity ranged from 0 to 351 nmol/min/mg. Phylogenetic comparative methods, implemented in BayesTraits showed that enzyme activity was strongly correlated with phylogeny, more so for LAAO activity. For example, LAAO activity was absent in both the Vermicella and Pseudonaja/Oxyuranus clade, supporting previously proposed relationships among these disparate taxa. There was no association between broad dietary categories and either enzyme activity. There was strong evidence for faster initial rates of change over evolutionary time for LAAO (delta parameter mean 0.2), but no such pattern in PLA2 (delta parameter mean 0.64). There were some exceptions to the phylogenetic patterns of enzyme activity: different PLA2 activity in the ecologically similar sister-species Denisonia devisi and D. maculata; large inter-specific differences in PLA2 activity in Hoplocephalus and Austrelaps.ConclusionsWe have shown that phylogeny is a stronger influence on venom enzyme activity than diet for two of the four major enzyme families present in snake venoms. PLA2 and LAAO activities had contrasting evolutionary dynamics with the higher delta value for PLA2 Some species/individuals lacked activity in one protein family suggesting that the loss of single protein family may not incur a significant fitness cost.

Determination of Mass Transfer Coefficients for Adsorption of Pb and Cd Onto Coir Pith and Statistical Analysis

Adsorption of Pb and Cd ions onto coir pith from single solute aqueous solutions was studied. Experimental data on variation of solute concentration in the solution with time were fitted to exponential kinetic model and model parameters were determined. New parameter, concentration decay constant, was introduced to comprehend the adsorption rate. Novel method was introduced to determine the liquid film mass transfer coefficient (kL) accurately using the exponential kinetic model equation. Liquid film mass transfer coefficient and Overall liquid phase mass transfer coefficient were calculated and the proposed method overcomes the errors due to approximation of initial rate of change of solute concentration and assumption of linear isotherm parameters. Statistical analysis of mass transfer coefficients showed that for all the parameters tested the variation of the parameters are significant with initial solution concentration for Pb.

Quantitative Phase-Field Simulation of Composition Partition and Separation Kinetics of Nanoscale Phase in Fe-Cr-Al Alloy

Phase separation of the Cr-enriched nanoscaleα′phase in the Fe-38 at.% Cr-10 at.% Al alloy is studied by utilizing phase-field simulation. The partition of elements in theαandα′phases is clarified with the composition evolution through theα/α′phase interface, and the separation kinetics is quantitatively investigated by the temporal evolution of the size and volume fraction of theα′phase. Aluminum partitions into the Fe-enrichedαphase and depletes in theα′phase, and the partition coefficient decreases as the temperature changes from 720 K to 760 K for the steady-state coarsening stage. As the temperature increases, the initial change rate of the volume fraction of theα′phase is faster, indicating an accelerated phase separation. At the coarsening stage, the average particle distance and coarsening rate constant of theα′phase increase with increased temperature, and the ratio of the Ostwald ripening is dominating compared with coalescence coarsening. The element partition and kinetics evolution of theα′phase with temperature are helpful for the morphology and property predication of nanoscale precipitates.

Delineating the age-related attenuation of vascular function: Evidence supporting the efficacy of the single passive leg movement as a screening tool.

Continuous passive leg movement (PLM) is a promising clinical assessment of the age-related decline in peripheral vascular function. To further refine PLM, this study evaluated the efficacy of a single PLM (sPLM), a simplified variant of the more established continuous movement approach, to delineate between healthy young and old men based on vascular function. Twelve young (26 ± 5 yr) and 12 old (70 ± 7 yr) subjects underwent sPLM (a single passive flexion and extension of the knee joint through 90°), with leg blood flow (LBF, common femoral artery with Doppler ultrasound), blood pressure (finger photoplethysmography), and leg vascular conductance (LVC) assessed. A receiver operator characteristic curve analysis was used to determine an age-specific cut score, and a factor analysis was performed to assess covariance. Baseline LBF and LVC were not different between groups (P = 0.6). The high level of covariance and similar predictive value for all PLM-induced LBF and LVC responses indicates LBF, alone, can act as a surrogate variable in this paradigm. The peak sPLM-induced increase in LBF from baseline was attenuated in the old (Young: 717 ± 227, Old: 260 ± 97 ml/min, P < 0.001; cut score: 372 ml/min), as was the total LBF response (Young: 155 ± 67, Old: 26 ± 17 ml, P < 0.001; cut score: 58 ml). sPLM, a simplified version of PLM, exhibits the prerequisite qualities of a valid screening test for peripheral vascular dysfunction, as evidenced by an age-related attenuation in the peripheral hyperemic response and a clearly delineated age-specific cut score. NEW & NOTEWORTHY Single passive leg movement (sPLM) exhibits the prerequisite qualities of a valid screening test for peripheral vascular dysfunction. sPLM displayed an age-related reduction in the peripheral hemodynamic response for amplitude, duration, initial rate of change, and total change with clearly delineated age-specific cut scores. sPLM has a strong candidate variable that is a simple single numeric value, for which to appraise peripheral vascular function, the 45-s hyperemic response (leg blood flow area under the curve: 45 s).

Patterns of symptomatology over time and their relation to outcome.

The purpose of this study was to examine the association between characteristics of the symptomatology change curve (i.e., initial symptomatology, rate of change, curvature) and final treatment outcome. The sample consisted of community clients (N = 492) seen by 204 student therapists at a training clinic. A multilevel approach to account for therapist effects was followed. Linear, quadratic, and cubic trajectories of anxiety and depression symptomatology, as assessed by the Shorter Psychotherapy and Counseling Evaluation (sPaCE; Halstead, Leach, & Rust, 2007), were estimated. The multilevel quadratic trajectory best fit the data and depicted a descending curve (partial “U”-shaped). The quadratic growth parameters (intercept, slope, quadratic) were then used as predictors of both symptom change and reliable improvement in general symptomatology (pre- to post-treatment), as assessed by the Outcome Questionnaire-45.2 (OQ-45.2; Lambert, Hansen, Umpress, Lunen, Okiishi et al., 1996). The quadratic growth parameters of depression and anxiety showed predictive power for both symptom change and reliable improvement in general symptomatology. Patterns for two different successful outcomes (1-change in general symptomatology and 2-reliable improvement) were identified. For symptom change, successful outcomes followed a pattern of low initial levels of depression and anxiety, high initial rates of change (slope), and high (flattening after initial drop) curvature, and the pattern applied to both within- and between-therapist levels. For reliable improvement at within-therapist level, successful outcomes followed a pattern of high initial rate of change (slope) and high curvature. For reliable improvement at between-therapist level, successful outcomes were associated with a pattern of low initial levels of depression and anxiety. Implications for clinical practice are discussed.

The effect of nanosecond pulsed high frequency discharges on the temperature evolution of ignition kernels

Nanosecond pulsed high frequency discharges (NPHFD) have attracted interest as a means of enhancing ignition probability and ignition kernel growth rates. Previous studies have shown that increasing the pulse repetition frequency (PRF) of a NPHFD burst can result in enhanced probability of ignition relative to lower values of PRF. The cause of this enhanced ignition probability is not well understood, in part, because the temperature evolution of ignition kernels have not been measured. In this work, an inverse deconvolution technique was developed, evaluated, and used to determine the temporal evolution of the temperature and volume of ignition kernels initiated by NPHFD and single pulse discharges. Radiation intensity measurements of ignition kernels were compared to modeled values to determine path-averaged temperatures. Comparisons of values derived using the deconvolution technique and measured temperatures above a McKenna burner typically agreed within 4%. When the technique was applied to ignition kernels initiated by NPHFD over a range of PRF, it was observed that increasing the PRF of a discharge sequence increased the initial rate of change of the temperature as compared to lower PRF. Additionally, kernels generated with high PRF discharges achieved higher initial peak temperatures than those generated by lower PRF discharges. A relaxation in temperature was observed following the peak, which was followed by a subsequent temperature increase in all cases generated with PRF > 10 kHz. PRF above 5 kHz result in larger initial kernel volumes and volume rates of change compared to those observed for lower PRF values. This is attributed to pulse-to-pulse coupling during the energy deposition process. The observed relationship between kernel temperature, volume, and PRF help to explain ignition probability measurements reported previously. Findings from the effort illustrate how the rate of energy deposition through pulse-to-pulse coupling can significantly enhance ignition through elevated temperatures.