Modulation spectroscopy study of a strained layer GaAs/GaAsP multiple quantum well structure

Using contactless electroreflectance (CER) and piezoreflectance at 300 K we have characterized a GaAs/GaAs_1?xP_x multiple quantum well (MQW) structure, “GaAs” (nominal) and GaAsP epilayers grown by chloride transport chemical vapor deposition on GaAs (001) substrates. From a detailed lineshape fit to the CER data from the epilayers we have determined the energies of the fundamental band gap and hence the phosphorous composition. The nominal “GaAs” epilayers were found to have phosphorous compositions of about 2.5–3.2%, a result of the phosphorous diffusion between growth chambers in the reactor. The GaAs_1?xP_x epilayer had x=0.29. For the GaAs_0.97P_0.03/GaAs_0.71P_0.29MQW comparison between the experimentally observed energies of a number of quantum transitions with a theoretical envelope function calculation, including the effects of strain in the barriers, made it possible to evaluate the unstrained conduction band offset parameter Q_c=0.50±0.05. Our value for this parameter is discussed in relation to other works. Atomic force microscopy was employed to investigate the surface morphology of the 230 Å GaAsP top layer of the MQW in addition to a 2000 Å GaAsP epilayer. From the absence of any cross-hatch pattern associated with misfit dislocations on the former we concluded that the GaAsP in the MQW is pseudomorphic. On the other hand the 2000 Å epilayer exhibited signs of strain relaxation.     

Sexual free behavior in male rats (Rattus norvegicus).

Male rats ( Rattus norvegicus) were given continuous access to estrous female rats for 24 hrs each day for 10 days. During the 1st 12 hrs, the rats achieved an average of 10 ejaculations, followed by a 1- to 2-day period with little sexual activity. During the last 7 days, the rats maintained a reasonably stable equilibrium level of 3 ejaculations per day. These occurred predominantly during the dark phase of the diurnal cycle, they frequently occurred in a cluster, and they usually occurred shortly after the introduction of a novel estrous female. Except for quantitative differences, these results are generally consistent with conventional research but systematically extend the generality of the results to the context of the free behavior situation. The availability of sexual activity had no appreciable effect on food and water intake, but it did decrease the amount of running activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus variables in the block design task: A commentary on Schorr, Bower, and Kiernan.

Contends that the block design task by D. Schorr et al (see record 1982-27118-001) replicates the earlier findings of the author and his colleague K. Weitzel (see PA, Vols 58:2589; 61:10327; and 61:12312). In addition, Schorr et al introduce a new paradigm to continue isolating information-processing components of the task. The present author takes issue with their finding regarding synthetic and analytic strategies because these terms are too global to advance knowledge of cognitive processes. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facilitation of sociomoral reasoning in delinquents.

An intervention involving 60 incarcerated juvenile delinquents (ages 14–18 yrs) yielded significant gains in sociomoral reasoning that were attributable to a dilemma-discussions treatment. The treatment consisted of 8 weekly small-group discussions of sociomoral dilemmas. Ss were pretested on the Sociomoral Reflection Measure (SRM) and the Dilemma Decisions Survey and were assigned to either consensus dilemma-discussion, nonconsensus dilemma-discussion, or no-discussion groups. Pretest results show that Ss initially differed in both sociomoral stage and dilemma opinion. Of the dilemma-discussions Ss, 87.5% were pretested at Modal Stage 2 on the SRM and shifted to Modal Stage 3 on the posttest, whereas only 14.3% of the Modal Stage 2 control Ss did so. Pretest Modal Stage 3 Ss remained at Stage 3 on the posttest. Across the experimental groups, no difference was found between groups where a consensus was required for the discussion and groups having no consensus requirement. Investigations of the possible in-program and postrelease behavioral ramifications of the dilemma-discussions treatment are recommended. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thrifty execution of task pipelines

Summary A sequence of tasks that must be performed on a sequential database can be scheduled in various ways. Schedules will differ with respect to the number of accesses made to peripheral storage devices and the amount of memory space consumed by buffers. Buffer requirements are discussed for task schedules that avoid accesses to peripherals storing the sequential database. The relationship between certain thrifty scheduling policies and loop jamming, a standard code optimization technique, is also identified. Application to UNIX pipelines and to file processing is discussed.This work is supported in part by NSF Grant MCS-8003340 and MCS-8103605. Schneider is also supported by a Faculty Development Grant from IBM Corporation     

Microwave Rejection Networks

This is an extension of the Bridged-T infinite rejection network idea transformed into microwave concepts. These devices achieve approximately 100db of attenuation with skirt attenuations approximately 5db. The tuning range between 1 KMc and 10 KMc is continuously covered with 4 units at present. Work is continuing to reduce the number of units to 2. Design parameters, performance curves, and application to MILSTD 826 will be discussed.     

The MMPI and chronic pain.

112 chronic pain patients (mean age 48.4 yrs) completed the MMPI upon entering either an anesthesiologic or a psychiatric treatment program. Pretreatment MMPI performance was found to be successful in predicting patient outcome an average of 20 mo following treatment, with the K (Test-Taking Attitude), Hypochondriasis, Hysteria, and Masculinity and Femininity scales accounting for most of the variance. The strength of this relationship varied as a function of the measure of outcome and type of treatment received. Substantial MMPI differences were found when Ss with only one part of their body in pain were compared with those with multiple pain complaints. Significant MMPI differences were also found in comparisons based on Ss' sex, type of pain (e.g., head vs back), and type of treatment for which was referred (i.e., psychiatric vs anesthesiologic). Clinical implications of the observed MMPI differences are discussed. Results are seen as demonstrating the value of the MMPI as a clinical and research instrument within this population. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)