Intra- versus intermodal integration in young and older adults

The ability to integrate information across sensory channels is critical for both within- and between-modality speech processing. The present study evaluated the hypothesis that inter- and intramodal integration abilities are related, in young and older adults. Further, the investigation asked if intramodal integration (auditory+auditory), and intermodal integration (auditory+visual) resist changes as a function of either aging or the presence of hearing loss. Three groups of adults (young with normal hearing, older with normal hearing, and older with hearing loss) were asked to identify words in sentence context. Intramodal integration ability was assessed by presenting disjoint passbands of speech (550-750 and 1650-2250 Hz) to either ear. Integration was indexed by factoring monotic from dichotic scores to control for potential hearing- or age-related influences on absolute performance. Intermodal integration ability was assessed by presenting the auditory and visual signals. Integration was indexed by a measure based on probabilistic models of auditory-visual integration, termed integration enhancement. Results suggested that both types of integration ability are largely resistant to changes with age and hearing loss. In addition, intra- and intermodal integration were shown to be not correlated. As measured here, these findings suggest that there is not a common mechanism that accounts for both inter- and intramodal integration performance.     

Dynamics and thermodynamics of tetragonal zirconia determined by 111In/Cd TDPAC

For several years this research group has been using ¹¹¹In/Cd TDPAC to study oxygen vacancies in pure and lightly doped zirconia powders at temperatures up to 1400°C. This paper includes a brief survey of important results from those studies and some recent results. In particular, our new measurement showing negligible relaxation due to vacancy hopping above 600°C provides a major breakthrough in our ability to analyze PAC data and to determine accurately hopping and trapping rates and enthalpies for vacancies in tetragonal zirconia. This revised version was published online in August 2006 with corrections to the Cover Date.     

Statistics of S-matrix poles in few-channel chaotic scattering: Crossover from isolated to overlapping resonances

We derive an explicit expression for the distribution of resonance widths in a chaotic quantum system coupled to continua via M equivalent open channels. It describes a crossover from the χ ² distribution (regime of isolated resonances) to a broad, power-law-like distribution typical for the regime of overlapping resonances. The first moment is found to reproduce exactly the Moldauer-Simonius relation between the mean resonance width and the transmission coefficient. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 12, 970–973 (25 June 1996) Petersburg Nuclear Physics Institute, 188350, Gatchina, St. Petersburg District, Russia Published in English in the original Russian journal. Edited by Steve Torstveit.     

Ab-initio calculation of the heat of formation in the metallic transition metal monoxides

In order to understand the cohesive properties of transition metal monoxides the ground state energies of the transition metal T, the monoxide TO and oxygen atom 0 involved in the reaction $\text{M}\text{+}\text{1}\text{2}\text{(}\text{0}{}_2\text{) ?}\text{M O}\text{+ Δ}\text{H}$ have been calculated for metallic TiO and VO following the density functional method in the augmented spherical wave approximation. The evaluated values of ΔH compare very well with those obtained experimentally.     

Characterization of a sealed Americium–Beryllium (AmBe) source by inductively coupled plasma mass spectrometry

Two Americium–Beryllium neutron sources were dismantled, sampled (sub-sampled) and analyzed via inductively coupled plasma mass spectrometry (ICP-MS). Characteristics such as “age” since purification, actinide content, trace metal content and inter and intra source composition were determined. The “age” since purification of the two sources was determined to be 25.0 and 25.4 years, respectively. The systematic uncertainties in the “age” determination were ±4% 2σ. The amount and isotopic composition of U and Pu varied substantially between the sub-samples of Source 2 (n = 8). This may be due to the physical means of sub-sampling or the way the source was manufactured. Source 1 was much more consistent in terms of content and isotopic composition (n = 3 sub-samples). The Be–Am ratio varied greatly between the two sources. Source 1 had an Am–Be ratio of 6.3 ± 52% (1σ). Source 2 had an Am–Be ratio of 9.81 ± 3.5% (1σ). In addition, the trace element content between the samples varied greatly. Significant differences were determined between Sources 1 and 2 for Sc, Sr, Y, Zr, Mo, Ba and W.     

Palladium(0)-catalyzed synthesis of chiral ene-allenes using alkenyl trifluoroborates

Enantioenriched allenes serve as chiral transfer reagents, making them attractive synthetic targets. Herein, the synthesis of enantioenriched allenes utilizing a Pd(0)-catalyzed cross-coupling reaction of propargylic carbonates and phosphates with alkenyl trifluoroborates is reported. Di-, tri-, and tetrasubstituted allenes were synthesized in moderate to high optical yields. Several racemic allenes possessing various functional groups were also synthesized.