A self-backgating GaAs MESFET model for low-frequency anomalies

A self-backgating GaAs MESFET model which can simulate low-frequency anomalies has been developed by including deep-level trap effects. These cause transconductance reduction due to electron emission from EL2 in the depletion width change at the edge of the Schottky gate junction and the output conductance to increase due to the time-dependent net negative charge concentration in the semi-insulating substrate as a result of self-backgating with the applied signal frequency. This model has been incorporated in PSPICE and includes a time-dependent I-V curve model, a capacitance model, an RC network describing the effective substrate-induced capacitance and resistance, and a switching resistance providing device symmetry. An analytical capacitance model describes the dependence of capacitance on V_gs and V_ds and includes the channel-substrate junction modulation by the self-backgating effect. A transit-time delay is also included in the transconductances, g_m and g_mbs, for model accuracy and to describe the phase shift of S-parameters. Measured data correspond to simulations by this model of the low-frequency anomalous characteristics, voltage-dependent capacitances, and S-parameters of conventional GaAs MESFETs for linear and microwave circuit design     

Psychodynamic formulation, consensual response method, and interpersonal problems.

We describe a new method for aggregating psychodynamic formulations of independent clinicians. 15 patients (10 female and 5 male, aged 23–41) were interviewed before they began brief dynamic psychotherapy. Different panels of 8 formulators (drawn from a pool of 72 psychodynamic clinicians with 10–38 years of clinical experience) observed each videotaped interview and wrote individual formulations. The text of each formulation was divided into thought-units, and thought-units that occurred 3 or more times were combined into a final consensual formulation. (One case was formulated twice to demonstrate the replicability of the method). Other clinical raters then read each consensual formulation and judged, for a list of interpersonal problems, whether each problem was apt to be distressing for that patient. The raters were very successful in predicting which problems were later discussed in treatment. Predictions were best for formulations with a high proportion of interpersonal content. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of the Hybrid Weight Assessment System for Multiple Quality Attributes

When designing a product or process, a design engineer is often faced with a number of quality attributes and hence prioritizing the quality attributes is an inevitable task. Development of an adequate weight assessment system for multiple attributes in the early stage of design is crucial, since the choice of paths to quality enhancement depends heavily upon the type of weight assessment system used. Although several weight assessment methods are available in the literature, there is room for improvement. Most weight assessment methods reported in the research community have been developed from the perspective of either customers or a design engineer. This article proposes a hybrid weight assessment system by combining the perspectives of both parties, the customer and a design engineer, in such a way that uncertainty of human perceptions can be modeled using the concepts of fuzzy sets and Monte Carlo simulation. A model is presented and a numerical example is discussed.     

Simulations of a thin sampling calorimeter with GEANT/FLUKA

The Advanced Cosmic-ray Composition Experiment for the Space Station (ACCESS) will investigate the origin, composition and acceleration mechanism of cosmic rays by measuring the elemental composition of the cosmic rays up to 10¹⁵ eV. These measurements will be made with a thin ionization calorimeter and a transition radiation detector. This paper reports studies of a thin sampling calorimeter concept for the ACCESS thin ionization calorimeter. For the past year, a Monte Carlo simulation study of a thin sampling calorimeter (TSC) design has been conducted to predict the detector performance and to design the system for achieving the ACCESS scientific objectives. Simulation results show that the detector energy resolution function resembles a Gaussian distribution and the energy resolution of TSC is about 40%. In addition, simulations of the detector's response to an assumed broken power law cosmic ray spectrum in the region where the ‘knee’ of the cosmic ray spectrum is believed to occur have been conducted and clearly show that a thin sampling calorimeter can provide sufficiently accurate estimates of the spectral parameters to meet the science requirements of ACCESS.     

Age-related decrement in auditory selective attention.

Young (n?=?30), middle-aged (n?=?32), and old (n?=?28) adults repeated (shadowed) words presented to the left ear at 60 words per minute with and without distracter words presented to the other ear. Dichotic shadowing error rate increased with age. An attempt to eliminate the age effect by adjusting for age differences in monaural shadowing errors, fluid intelligence, and pure-tone hearing loss did not succeed. When the analyses were confined to Ss who made no monaural shadowing errors, dichotic shadowing errors still increased linearly with age. These results showed that there are selective-attention deficits in older adults that cannot be accounted for by the uncertainty of the target location. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in energy balance following smoking cessation and resumption of smoking in women.

Caloric intake, resting metabolic rate (RMR), leisure-time physical activity, and sensitivity and preference for sweet taste were prospectively examined in 7 female smokers across 3 weeks during periods of normal smoking (Week 1), complete cessation (Week 2), and resumption of smoking (Week 3). Energy balance changed significantly across weeks, as caloric intake increased (largely as a result of alcohol consumption) and RMR decreased during cessation, followed by decreased caloric intake and increased RMR with resumption of smoking. Activity and taste sensitivity and preference remained unchanged. Smoking cessation may thus cause rapid change in energy balance, which is quickly reversed on resumption of smoking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of IP3 in p-i-n photodetectors and proposed performancerequirements for RF fiber-optic links

The nonlinearities generated by wide-band, high-current photodetectors are discussed in the context of the performance of an externally modulated analog radio-frequency fiber-optic link. The quantitative impart of the detector's third-order intermodulation product intercept (IP3) on the link's spur-free dynamic range is analyzed. Waveguide p-i-n photodiodes were developed to specifically address these stringent IP3 goals. The IP3 was measured using a four laser heterodyne system resulting in an IP3 of 27 dBm measured at a center frequency of 20 GHz with 20 mA of de photocurrent. The authors believe that this is the highest photodetector IP3 reported to date at these operating conditions     

Nonhuman primate neuroimaging and cocaine medication development.

Given the important role of the dopamine transporter (DAT) in the addictive properties of cocaine, the development and use of compounds that target the DAT represents a reasonable approach for the pharmacological treatment of cocaine abuse. The present report describes a series of studies conducted in nonhuman primates that evaluated the effectiveness of DAT inhibitors in reducing cocaine self-administration. In addition, drug substitution studies evaluated the abuse liability of the DAT inhibitors. Positron emission tomography neuroimaging studies quantified DAT occupancy at behaviorally relevant doses, characterized the time-course of drug uptake in brain, and documented drug-induced changes in cerebral blood flow as a model of brain activation. Selective DAT inhibitors were effective in reducing cocaine use but high (>70%) levels of DAT occupancy were associated with significant reductions in cocaine self-administration. The selective DAT inhibitors were reliably self-administered but rates of responding were lower than those maintained by cocaine even at higher levels of DAT occupancy. A profile of slow rate of drug uptake in brain accompanied by a gradual increase in extracellular dopamine may account for the more limited reinforcing effectiveness of the DAT inhibitors. Selective serotonin transporter (SERT) inhibitors were also effective in reducing cocaine use and blocked cocaine-induced brain activation and increases in extracellular dopamine. Coadministration of SERT inhibitors with a selective DAT inhibitor was more effective than the DAT inhibitor administered alone, even at comparable levels of DAT occupancy. The results indicate that combined inhibition of DAT and SERT may be a viable approach to treat cocaine addiction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Melodrama and film noir on today's big screen: How modern audiences experience yesterday's classics.

In the 1940s and 50s, melodrama was described as "the lady's film," whereas men were the supposed fans of film noir. No empirical studies were conducted with filmgoers of that era to validate such claims. This study examined responses of modern-day audiences comprising 16 females and 16 males to these classic genres. An experimental montage technique was developed to compare problem and solution scenes excerpted from 4 melodrama and 4 film noir movies. Participants rated each scene on fifteen 5-point scales related to cognitive and emotional responses and interpreted the meaning of each scene open-endedly. Quantitative analyses indicated that subjects were more sensitive to the character's emotions in melodrama, found this genre to be more complex, and were more apt to experience personal memories. Qualitative analyses revealed that subjects were more aware of the character's emotions and were more likely to identify with the character in melodramas. Interactions showed that participants judged the solution scenes in film noirs to be unrealistic and criticized the main character's actions. Male and female participants did not differentially respond to the two genres. (PsycINFO Database Record (c) 2010 APA, all rights reserved)