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This study examined whether musical training, ethnicity, and experience with a natural tone language influenced sensitivity to tone while listening to an artificial tone language. The language was designed with three tones, modeled after level-tone African languages. Participants listened to a 15-min random concatenation of six 3-syllable words. Sensitivity to tone was assessed using minimal pairs differing only in one syllable (nonword task: e.g., to-kà-su compared to ca-fí-to) or only in tone (tone task: e.g., to-kà-su compared to to-ká-su). Proficiency in an East Asian heritage language was the strongest predictor of success on the tone task. Asians without tone language experience were no better than other ethnic groups. We conclude by considering implications for research on second language learning, especially as approached through artificial language learning.
Background: We evaluated whether quality of life correlates to age and activity in children following heart transplantation. In addition, quality of life in children following heart transplantation was compared with previously reported values in children with congenital heart disease. Quality of life remains an important aspect of therapy. Methods: The Pediatric Quality of Life Inventory Generic Core Scales and Cardiac Module were administered to 14 children who had previously undergone heart transplantation. Patients wore a pedometer for 7 days to assess daily activity. Results: The age at assessment was 13.1±1.9 years. The patients were 7.1±5.7 years post heart transplantation. There was a negative correlation between age at first heart transplantation and emotional (r=−0.64; p<0.05) and school function (r=−0.57; p<0.05). A negative correlation between patient’s age at assessment and perceived physical appearance existed (r=−0.53; p<0.05). Daily steps negatively correlated with cognitive (r=−0.58; p<0.05), physical (r=−0.63; p<0.05), emotional (r=−0.62; p<0.05), and school function (r=−0.66; p<0.01). Heart transplantation patients reported better scores for treatment and symptoms (p<0.05) but lower physical health scores (p<0.01) than those with moderate congenital heart disease. Conclusions: Paediatric heart transplantation patients reported overall similar quality of life as patients with moderate congenital heart disease. Children receiving heart transplants at an older age may require additional emotional and educational support. Heart transplantation patients with higher activity levels may be more aware of their physical, emotional, and cognitive limitations, and thus score lower on these quality of life indicators.
Modifications to the p-type semiconductor TIPS-Pentacene can result in elimination of the solid-solid thermal transition at 124 °C. This new material has shown mobility higher than 1 cm2/Vs. Elimination of the solid-solid thermal transition leaves the melting point as the lowest temperature transition at 199 °C.
The forward voltage drop (Vf) increase observed in 4H-SiC bipolar devices such as pin diodes due to recombination-induced Shockley stacking fault (SSF) creation and expansion has been widely discussed in the literature. It was long believed that the deleterious affect of these defects was limited to bipolar devices. However, it was recently reported that forward biasing of the body diode of a 10kV 4H-SiC DMOSFET led to similar Vf increases in the body diode I-V curve as well as a corresponding degradation in the majority carrier conduction characteristics as well and this degradation was believed to be due to the creation and expansion of SSFs during the body diode forward biasing. Here we report measurements comparing the influence of similar stressing, along with annealing and current-induced recovery experiments in DMOSFETs and merged pin-Schottky diodes with the previously reported results of these experiments in 4H-SiC pin diodes. The results of these experiments provide sufficient support that the observed degradation in the majority carrier conduction characteristics is the result of SSF expansion.
Synchrotron x-ray topographs taken using basal plane reflections indicate that the electron-hole recombination activated Shockley partial dislocations in 4H silicon carbide bipolar devices appear as either white stripes with dark contrast bands at both edges or dark lines. In situ electroluminescence observations indicated that the mobile partial dislocations correspond to the white stripes in synchrotron x-ray topographs, while immobile partial dislocations correspond to the dark lines. Computer simulation based on ray-tracing principle indicates that the contrast variation of the partial dislocations in x-ray topography is determined by the position of the extra atomic half planes associated with the partial dislocations lying along their Peierls valley directions. The chemical structure of the Shockley partial dislocations can be subsequently determined unambiguously and non-destructively.
Electroluminescence (EL) and photoluminescence (PL) imaging and stressing techniques are presented that are useful characterization tools for SiC epitaxial layers grown for power devices. Both EL and PL techniques are non-destructive, and the PL imaging is non-contact. These features are important for qualifying epitaxial layers before subjecting the layers to the time-consuming and costly process of device fabrication. By imaging at various emission spectral bands, the spectral information are correlated to the geometric features in the images. This correlation enables the differentiation of dissimilar defects having similar geometric shapes. Row average plots of images at various emission spectral bands revealed that threading dislocations (TDs) have strong emission above 900 nm and that basal plane dislocations (BPDs) have a broad spectral emission that are most easily distinguished in the range between 738 nm and 870 nm. The correlation between spectral information and the image features clearly distinguished TDs and BPDs from other defects, such as, organic substance and other surface blemishes. In addition to identifying the defects, understanding their origin can be useful in developing low-defect growth techniques. The defect origination depth is one of the important information for understanding defect origin. Two schemes for determining the defect origination depth are presented. Varying the focus depth by adjusting the objective lens height is a crude but quick scheme. Stressing the epilayer to grow the BPDs till they reach the surface or the epilayer/substrate interface is more time-consuming but more accurate. The scheme of varying the focus was demonstrated using PL imaging on a 50-mm thick n- epilayer with no p+ anode layer. Adjusting the focus on a partial dislocation in the n- epilayer revealed segments of the partial coming more in focus near the epilayer/substrate interface, suggesting the defect origination depth was at or near the interface. The stress and growth scheme was demonstrated on a straight string of half loop defects in a 100-mm thick n- epilayer. During electrical stressing, BPDs emanated from the half loops and eventually propagated to the surface at a lateral distance of 250 mm. With the basal plane at an 8° offcut from the surface, the origin of the BPDs was calculated to be 35 mm below the surface, suggesting the defects to be introduced during the growth process. Either EL or PL technique can be used with any of these two schemes to determine the defect origination depth. However, the PL technique has the benefit that the p+ anode layer and the procedure for forming a metal grid are not required.
Here we present optical beam induced current, electroluminescence, time resolved photoluminescence and current-voltage measurements on several 4H-SiC PiN diodes containing in-grown stacking faults (IGSFs). These defects were observed to act as either current shorts, creating a direct electrical contact between the p+ and n+ layers, or as a current barrier. Carrier lifetime measurements verify that the change in behavior is indeed associated with changes in the conductivity of the material in the vicinity of the defect and not due to local changes in the carrier lifetime. The IGSFs discussed here appear to differ from those previously discussed in the literature and may constitute a new, multi-layered IGSF.
Termination of GABA signals within the retina occurs through
high-affinity reuptake of the released neurotransmitter by GABA
transporters (GATs) present in neurons and glia surrounding the release
site. In the present work, we have cloned a novel GAT from the retina of
the skate (Raja erinacea). The clone codes for a 622 amino acid
protein whose sequence has highest similarity to the
GABA/β-alanine transporter of the electric ray (Torpedo
marmorata) (88% identity) and the GAT-3 isolated from rat brain (75%
identity). The protein was expressed in Xenopus oocytes and
characterized using the two-electrode voltage-clamp technique. Application
of GABA induced a dose-dependent inward current, with 8 μM GABA
producing a half-maximal response. The current required the presence of
extracellular sodium and was unaffected by the GABA receptor blocker
picrotoxin or the GAT-1 specific antagonist NO-711. The high homology
between the cloned skate GABA transporter and the GAT-3 equivalents of
other species, coupled with the strikingly similar pharmacological profile
to GAT-3s of other species, lead us to conclude that we had cloned the
GAT-3 homologue for the skate. Polyclonal antibodies specific to GAT-3 and
the previously cloned skate GAT-1 transporter were used to examine the
distribution of GAT-3 and GAT-1 immunoreactivity in the retina and in
isolated cells of the skate. Antibodies for both transporters showed
labeling in the outer and inner plexiform layers, and staining extended
from the outer to inner limiting membranes. Both GAT-1 and GAT-3
antibodies labeled enzymatically isolated Müller cells, while bipolar
cells and horizontal cells did not appear to express either transporter.
These results imply that GAT-1 and GAT-3 are both present in Müller
cells of the skate retina where they are likely involved in regulating
extracellular concentrations of GABA.
We have developed and tested a wide-field photometer to detect extrasolar planet transits from the South Pole. The discovery of transiting planets for which masses can be measured by radial velocity is vital to constrain the models of planet formation and evolution. Short of going to space, the South Pole is the best site from which to carry out a such a survey. Based on results from the Doppler velocity surveys and the Vulcan transit search, we expect to detect 10 to 15 transiting planets in two years of operation at the South Pole.
As reported in Chapter 2, despite a number of important advances in mechanical ventilatory support, intensive care unit technology, and critical care training, the mortality due to complications of acute respiratory distress syndrome (ARDS) and/or multiorgan failure has not significantly changed during the past 20 years. The failure to fully advance new therapeutic schemes to treat patients with sepsis and ARDS likely reflects our limited knowledge regarding the basic mechanisms underlying these diseases. Thus, the ability to further diminish morbidity and increase survival requires an in-depth understanding of the important mediators involved in the evolution of these syndromes. This information could in turn provide clues as to what exogenous (microorganisms and their products) and endogenous (hostderived) factors should be targeted for modification or elimination during the various phases of sepsis leading to ARDS.
The pathogenesis of ARDS and multiorgan failure-complicating sepsis remains to be fully elucidated. However, polymicrobial agents, products derived from these microorganisms, and the subsequent host response to these factors are key determinants for the initiation and later perpetuation of organ injury. In fact, the host's own response to the initial challenge may be a more critical determinant to the outcome of sepsis and ARDS than the original inciting agent. This concept is supported by the findings that many of the multiple effects of bacterial-derived products, such as endotoxin and muramyl dipeptide, are largely indirect. These compounds exert their biologic effects in vivo by initiating a variety of mediator’ generating cascades, including coagulation and complement, vasoactive compounds, reactive oxygen and nitric oxide, arachidonic acid metabolites, and cytokines.
Variations in gel aging times and temperatures are shown to affect the optical properties of a gel-derived GRIN lens. These properties include the variation of the total index change as well as the shape of the index profile. However, these optical properties do not appear to correlate with the amount of modifier removed during the leaching step. Also, regardless of aging, gels appear identical with respect to calcining response and composition of pore liquid.
This article examines the frequency and stability of externalizing symptoms in a sample of 325 5-year-olds. Parent and teacher ratings, teacher nominations, parent-child interaction, and child measures were obtained. Using cutoff scores on teacher ratings, an average of 20% of the children were rated as having moderate externalizing problems in kindergarten and first grade. For both boys and girls, parent-teacher stability correlations ranged from .34–.45, and kindergarten teacher ratings from November and April correlated at .76. Instability in externalizing symptoms from kindergarten to first grade was related to a number of concurrent and previously assessed factors. For girls these included learning problems, shy-anxious behavior, mother-child interaction measures, and cognitive ability. Factors related to instability for boys included learning problems, social skills, cognitive ability, and self-control. These variables accounted for an additional 40% of the variance for boys (50% for girls) in first grade externalizing symptoms after controlling for externalizing symptoms in kindergarten.
Optical quality radial gradient-index (GRIN) glass can be made by first leaching a TiO2-Al2O3-SiO2 gel in aqueous sulfuric acid solution, then drying and firing the gel. In this paper, we present details of a study on the reproducible production of GRIN glasses by this sol-gel process. Physical and optical data on the intermediate gels and resulting gradient-index glass will be discussed.
Science-based biotechnology is now introducing fundamental changes in the status of life on earth which have major implications for human society, yet the social sciences are largely failing to address these changes. Biotechnology offers immense opportunities for advancing the quality of human life, holding promise for overcoming numerous and heretofore intractable causes of suffering and impoverishment. Moreover, it may enable mankind to enjoy the benefits of science without degradation of the biosphere. But to obtain these advantages biotechnology must be guided by wise and timely public policies. Even the most beneficent innovation may create problems that, unless anticipated and prevented, may offset or cancel out social gains.