Strained InGaAs-GaAs single-quantum-well lasers coupled to n-typeδ-doping-improved static and dynamic performance

A new concept for improving the performance of quantum-well (QW) lasers is reported. The enhancement, both in static and dynamic characteristics, was accomplished by the use of Te n-type δ-doping, coupled to a single strained InGaAs-GaAs QW. The internal parameters were investigated, and their enhancement origin is revealed. It is shown to be mainly a consequence of the higher carrier population in the QW and due to the strong coupling between the QW and the δ-doping well     

Implementation aspects for successive interference cancellation in DS/CDMA systems

This paper addresses the practical implementation of Successive Interference Cancellation (SIC) for DS/CDMA systems. The practical aspects of such an implementation are discussed and a convenient pipelined architecture is presented. An important aspect is the integration of power control (PC) and interference cancellation which has synergistic effects of optimizing the SIC, reducing intercell interference, and facilitating the implementation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Misgivings about the Matching Familiar Figures Test: Premature or overdue?

This note responds to the arguments and evidence adduced by Kagan (1987) in his reply to the Block, Gjerde, and Block (1986) study questioning the validity of the Matching Familiar Figures Test (MFFT) as a measure of "reflection–impulsivity." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of functional magnetic resonance imaging

It has been the goal of this article to provide the reader with a brief background of fMRI, a basic understanding of the techniques of fMRI, and, more importantly, the potential for clinical and experimental studies using fMRI. In contrast to the limited number of installed PET and MEG units, the large installed base of MR imaging scanners (over 1000 installed at least at 1.5 T in the United States) makes fMRI potentially widely available. Initial studies (both clinical and experimental) have been validated and are reproducible in mapping the sensorimotor and visual cortices. The areas of language lateralization and memory are still preliminary at best. As methods to reduce the effects of head motion (due to both bulk head motion and physiologically induced motion) arise, the reliability of fMRI should improve, allowing for more definitive identification of task activation.     

The social–cognitive construction of psychotherapeutic change: Bridging social constructionism and cognitive constructivism.

Self-with-other processing and construction play an important role in human adjustment, development, and change. This idea is critical for an adequate understanding of psychotherapy and psychotherapeutic change. A theory of psychotherapeutic change that combines elements of both social constructionist and cognitive constructivist thought is presented briefly. After reviewing salient examples of both forms of thought as these have manifested in theorizing about psychotherapeutic change, a sampling of original empirical demonstrations is offered in support of the theory. Psychotherapeutic change is described as a process of appropriation and practical application through which clients internalize therapeutic conversations and activities, which they then use as psychological tools to restructure personal theories, experiences, and actions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heterozygosity for a defective gene for CC chemokine receptor 5 is not the sole determinant for the immunologic and virologic phenotype of HIV-infected long-term nonprogressors

HIV-1-infected long-term nonprogressors are a heterogeneous group of individuals with regard to immunologic and virologic markers of HIV-1 disease. CC chemokine receptor 5 (CCR5) has recently been identified as an important coreceptor for HIV-1 entry into CD4+ T cells. A mutant allele of CCR5 confers a high degree of resistance to HIV-1 infection in homozygous individuals and partial protection against HIV disease progression in heterozygotes. The frequency of CCR5 heterozygotes is increased among HIV-1- infected long-term nonprogressors compared with progressors; however, the host defense mechanisms responsible for nonprogression in CCR5 heterozygotes are unknown. We hypothesized that nonprogressors who were heterozygous for the mutant CCR5 gene might define a subgroup of nonprogressors with higher CD4+ T cell counts and lower viral load compared with CCR5 wild-type nonprogressors. However, in a cohort of 33 HIV-1-infected long-term nonprogressors, those who were heterozygous for the mutant CCR5 gene were indistinguishable from CCR5 wild-type nonprogressors with regard to all measured immunologic and virologic parameters. Although epidemiologic data support a role for the mutant CCR5 allele in the determination of the state of long-term nonprogression in some HIV-1- infected individuals, it is not the only determinant. Furthermore, long-term nonprogressors with the wild-type CCR5 genotype are indistinguishable from heterozygotes from an immunologic and virologic standpoint.     

Predictive validity and internal consistency of the pre-hospital index measured on-site by physicians

Physiological measures of injury are used as triage tools to identify patients that require treatment in trauma centres. The Pre-Hospital Index (PHI) is based on systolic blood pressure, pulse, respiratory rate, (level of) consciousness, and presence of penetrating injury. The present study evaluated the validity and internal consistency of the PHI. The study was based on 628 patients assessed by physicians at the scene. Mean age was 38.7 years (SD = 24.8), and 65% were male. Motor vehicle collisions caused the injury for 45%. The majority had head/neck (56%) and extremity (45%) injuries. Mean PHI was 4.62 (SD = 5.77), 40% had a PHI of zero, 6% between 1 and 3, 32% between 4 and 7, and 21% greater than 7. The associations between PHI and rates of hospital admission, surgery, ICU treatment, mortality, duration of hospitalization, and length of ICU stay were significant (p < 0.001). A total of 260 (41.4%) patients had major trauma requiring treatment at a trauma centre. A PHI> 3 had 83% sensitivity and 67% specificity for identifying these patients. Internal consistency of the PHI variables was above the acceptable limits. This study has shown that the PHI is a valid and reliable physiological measure of injury severity and field triage tool.     

Two-Dimensional Micromachined Flow Sensor Array for Fluid Mechanics Studies

We discuss two types of micromachined flow sensors realized by using novel microfabrication processes—a hot-wire anemometer (based on thermal transfer) and a biologically inspired flow sensor (based on momentum transfer). Both sensors are enabled by a new, efficient three-dimensional assembly technique called the plastic deformation magnetic assembly method. The sensors can be packaged in high-density, two-dimensional arrays efficiently, with each sensor node capable of performing two-component or three-component flow sensing. We first discuss the development of new hot-wire anemometers (HWA). The HWA uses a thermal element (hot wire) that is made of Pt/Ni/Pt film with a measured temperature coefficient of resistance of 2,700 ppm/°C. The thermal element is elevated out of plane by using support beams made of polyimide, a polymer material. Both steady-state and transient characteristics of the sensor have been experimentally obtained. The second type of flow sensor is based on momentum transfer principles and inspired by fish lateral line sensors. Each sensor consists of a vertical cilium attached to a horizontal cantilever. Fluid flow imparts moment on the vertical cilium, and causes the horizontal cantilever to bend. The fabrication process and preliminary measurement data are presented.     

The Thematic Mapper?an Overview

The Thematic Mapper (TM) is a second-generation Earth resources sensor built by Hughes Aircraft Company for NASA for the LANDSAT series of spacecraft. The TM was placed in orbit aboard the LANDSAT-D spacecraft in July of 1982. Its predecessor, the Multispectral Scanner (MSS) has flown on LANDSAT's 1 through 3 and accompanies the TM on LANDSAT-D. The need for improved performance was recognized prior to the launch of the first MSS on LANDSAT-1 in 1972. The performance specifications for the TM were formulated to produce performance improvements in the next generation sensor. This paper will provide an overview of TM and will briefly discuss the LANDSAT-D mission and orbit, TM design, instrument performance, and program status.