Interference between phonemes during monitoring: Evidence for an interactive activation model of speech perception.

Explored the finding by J. E. Newman and G. S. Dell (see record 1981-00233-001) that the time needed to detect a target phoneme in a phoneme monitoring task increased when the preceding word contained a phoneme similar to the target. In 3 experiments, 58 undergraduates who were native speakers of English monitored auditorily presented sentences and responded as quickly as possible whenever they detected a specified phoneme. Preceding word-initial phonemes, despite being processed more quickly, increased the response latency to the following target phoneme more than did preceding word-medial phonemes. There was also an increase in response latency even when the S could be highly certain that the similar preceding phoneme was not an instance of the target phoneme. It is argued that the interference effects are due to fundamental characteristics of perceptual processing and that more time is needed to categorize the target phoneme. A computer simulation using an interactive activation model of speech perception is presented to demonstrate the plausibility of this explanation. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developing narrative structure in parent–child reminiscing across the preschool years.

This study is a longitudinal exploration of relations between parents' and children's provision of narrative structure in joint retellings of the past and children's developing personal narrative skills. 15 White, middle-class families participated when children were 40 and 70 mo old. At both ages, mothers and fathers talked separately with children about shared past events and uninformed experimenters elicited children's personal narratives. Whereas mothers and fathers did not differ in how they structured past narratives, children narrated differently with fathers than with mothers. Further, even at 40 mo, girls' narratives were more contexted and evaluative than boys', but parents' provision of narrative structure increased similarly with daughters and sons over time. Children's early abilities to provide evaluative narratives was a strong predictor of their later abilities to provide evaluative narratives; maternal emphasis on evaluations also predicted children's later narrative structure. Parental and child influences on personal narrative skill development are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of lithium on calcium-induced changes in adrenocorticotrophin levels

The calcium receptor (CaR) plays a central role in calcium (Ca) sensing by the parathyroid gland and other organs, including the brain. Chronic lithium (Li) therapy causes a significant alteration in Ca-sensing by the CaR-expressing parathyroid chief cells through an unknown mechanism, shifting the PTH set-point (the level of Ca that half-maximally suppresses PTH secretion) to the right. Ca is known to stimulate ACTH levels in normal subjects, and baseline ACTH levels are increased in patients with bipolar disorder. Because the stimulation of ACTH secretion by Ca likely involves the CaR, the aim of this study was to investigate the effects of Li on Ca-induced changes in ACTH levels, using Ca and citrate infusions in seven Li-treated patients and seven controls. During the Ca infusion, increments in serum-ionized Ca concentration (Ca(i)) were accompanied by increments in ACTH levels that were significantly greater in the Li-treated group, P = 0.014, by ANOVA. Also, cortisol levels increased significantly in the Li-treated, but not the control group, during the Ca infusion, P < 0.0001. There was a statistically significant shift in the midpoint of the Ca(i)/ACTH curve, to the right, in the Li-treated group, compared with the controls (P = 0.042), that was largely caused by an effect of Li on Ca(i). However, for comparable levels of Ca(i), there were no significant differences in the levels of ACTH between the two groups. Therefore, within the physiological range of Ca, there was no effect of Li on Ca(i)-induced change in ACTH levels.     

High power, 60 W quasi-CW, visible laser diode arrays

Visible spectrum diode arrays have been fabricated from (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P-Ga/sub 0.4/In/sub 0.6/P quantum well heterostructures operating to high output powers at wavelengths of approximately 690 nm. Bars 7.5 mm long with 110 mu m broad area emitting apertures on 125 mu m centers have reached quasi-CW output powers of 60 W.<>     

Statistical characterization of the geometric properties of particles in 7075‐T6 aluminium alloy

Corrosion in aluminium alloys is initiated and sustained at constituent particles within the metal matrix via a localized galvanic process. These particles are also known to play a critical role in fatigue crack initiation and growth. Consequently, statistical characterization of particle geometrical features is critical when modelling corrosion and fatigue. A key statistic is particle size distribution, which was extensively modelled here via imaging of unstressed and fatigued 7075‐T6 aluminium alloys. Fatigued samples were obtained from the outer wing panels of teardown specimens from retired military aircraft. The purpose of this effort was therefore to analyse extensive sets of particle geometry data obtained via microscopy using advanced multimodal statistical modelling and to appropriately characterize the properties of constituent particles and fatigue cracks found in these specimens. The resulting distribution functions for the underlying modes are assumed to be three‐parameter Weibull distribution functions.     

A fully planar p-n-p heterojunction bipolar transistor

The fabrication of fully planar p-i-n heterojunction bipolar transistors is reported. The devices were constructed using ion implantation into AlGaAs/GaAs heterostructures grown by metalorganic chemical vapor deposition (MOCVD). Incremental current gains of 100 have been observed for transistors with 22 μm×4 μm emitters, No emitter size effects was observed     

Reminiscing with different children: Relating maternal stylistic consistency and sibling similarity in talk about the past.

This study explored patterns of consistency and change in maternal reminiscing style across conversations with different children in the same family. Twenty-three White, middle-class mothers engaged in separate memory conversations with their younger (M age?=?40 months) and older (M age?=?68 months) children. Mothers evidenced striking stylistic consistency. Analyses of bidirectional relations revealed that for different elements of style, mothers' use of a stylistic dimension with one of the children predicted mothers' use of the same dimension with the other child in the family, above the variance accounted for by the siblings' participation. The results address questions concerning the strategic and responsive nature of maternal reminiscing style and the similarity of environments for learning autobiographical memory skills for different children within families. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High power diode laser arrays

Recent progress in the development of high-power diode laser arrays for solid-state laser pumping is detailed. Advances in available wavelength, efficiency, temperature of operation, duty cycle of operation, and peak and average power levels or densities are described. A packaging architecture capable of addressing the broadest range of pump applications and designs in an economic manner is defined, and a range of such package designs is presented     

Progress Toward an Integration of Process–Structure–Property–Performance Models for “Three-Dimensional (3-D) Printing” of Titanium Alloys

Electron beam direct manufacturing, synonymously known as electron beam additive manufacturing, along with other additive “3-D printing” manufacturing processes, are receiving widespread attention as a means of producing net-shape (or near-net-shape) components, owing to potential manufacturing benefits. Yet, materials scientists know that differences in manufacturing processes often significantly influence the microstructure of even widely accepted materials and, thus, impact the properties and performance of a material in service. It is important to accelerate the understanding of the processing–structure–property relationship of materials being produced via these novel approaches in a framework that considers the performance in a statistically rigorous way. This article describes the development of a process model, the assessment of key microstructural features to be incorporated into a microstructure simulation model, a novel approach to extract a constitutive equation to predict tensile properties in Ti-6Al-4V (Ti-64), and a probabilistic approach to measure the fidelity of the property model against real data. This integrated approach will provide designers a tool to vary process parameters and understand the influence on performance, enabling design and optimization for these highly visible manufacturing approaches.