Effectiveness of computer-based auditory training in improving the perception of noise-vocoded speech

Five experiments were designed to evaluate the effectiveness of “high-variability” lexical training in improving the ability of normal-hearing subjects to perceive noise-vocoded speech that had been spectrally shifted to simulate tonotopic misalignment. Two approaches to training were implemented. One training approach required subjects to recognize isolated words, while the other training approach required subjects to recognize words in sentences. Both approaches to training improved the ability to identify words in sentences. Improvements following a single session (lasting 1–2 h) of auditory training ranged between 7 and 12 %pts and were significantly larger than improvements following a visual control task that was matched with the auditory training task in terms of the response demands. An additional three sessions of word- and sentence-based training led to further improvements, with the average overall improvement ranging from 13 to 18 %pts. When a tonotopic misalignment of 3 mm rather than 6 mm was simulated, training with several talkers led to greater generalization to new talkers than training with a single talker. The results confirm that computer-based lexical training can help overcome the effects of spectral distortions in speech, and they suggest that training materials are most effective when several talkers are included

Definition of smolder experiments for Spacelab

The feasibility of conducting experiments in space on smoldering combustion was studied to conceptually design specific smoldering experiments to be conducted in the Shuttle/Spacelab System. Design information for identified experiment critical components is provided. The analytical and experimental basis for conducting research on smoldering phenomena in space was established. Physical descriptions of the various competing processes pertaining to smoldering combustion were identified. The need for space research was defined based on limitations of existing knowledge and limitations of ground-based reduced-gravity experimental facilities

The starting transient of solid propellant rocket motors with high internal gas velocities

A comprehensive analytical model which considers time and space development of the flow field in solid propellant rocket motors with high volumetric loading density is described. The gas dynamics in the motor chamber is governed by a set of hyperbolic partial differential equations, that are coupled with the ignition and flame spreading events, and with the axial variation of mass addition. The flame spreading rate is calculated by successive heating-to-ignition along the propellant surface. Experimental diagnostic studies have been performed with a rectangular window motor (50 cm grain length, 5 cm burning perimeter and 1 cm hydraulic port diameter), using a controllable head-end gaseous igniter. Tests were conducted with AP composite propellant at port-to-throat area ratios of 2.0, 1.5, 1.2, and 1.06, and head-end pressures from 35 to 70 atm. Calculated pressure transients and flame spreading rates are in very good agreement with those measured in the experimental system

Presentation modality influences behavioral measures of alerting, orienting, and executive control

The Attention Network Test (ANT) uses visual stimuli to separately assess the attentional skills of alerting (improved performance following a warning cue), spatial orienting (an additional benefit when the warning cue also cues target location), and executive control (impaired performance when a target stimulus contains conflicting information). This study contrasted performance on auditory and visual versions of the ANT to determine whether the measures it obtains are influenced by presentation modality. Forty healthy volunteers completed both auditory and visual tests. Reaction-time measures of executive control were of a similar magnitude and significantly correlated, suggesting that executive control might be a supramodal resource. Measures of alerting were also comparable across tasks. In contrast, spatial-orienting benefits were obtained only in the visual task. Auditory spatial cues did not improve response times to auditory targets presented at the cued location. The different spatial-orienting measures could reflect either separate orienting resources for each perceptual modality, or an interaction between a supramodal orienting resource and modality-specific perceptual processing

Global Transcriptional Response of the Alkalitolerant Cyanobacterium Synechocystis sp. Strain PCC 6803 to pH 10.

Many cyanobacterial strains are able to grow at a pH range from neutral to pH 10 or 11. Such alkaline conditions favor cyanobacterial growth (e.g., bloom formation), and cyanobacteria must have developed strategies to adjust to changes in CO2 concentration and ion availability. Synechocystis sp. strain PCC 6803 exhibits similar photoautotrophic growth characteristics at pH 10 and pH 7.5, and we examined global gene expression following transfer from pH 7.5 to pH 10 to determine cellular adaptations at an elevated pH. The strategies used to develop homeostasis at alkaline pH had elements similar to those of many bacteria, as well as components unique to phototrophic microbes. Some of the response mechanisms previously identified in other bacteria included upregulation of Na+/H+ antiporters, deaminases, and ATP synthase. In addition, upregulated genes encoded transporters with the potential to contribute to osmotic, pH, and ion homeostasis (e.g., a water channel protein, a large-conductance mechanosensitive channel, a putative anion efflux transporter, a hexose/proton symporter, and ABC transporters of unidentified substrates). Transcriptional changes specific to photosynthetic microbes involved NADH dehydrogenases and CO2 fixation. The pH transition altered the CO2/HCO3− ratio within the cell, and the upregulation of three inducible bicarbonate transporters (BCT1, SbtA, and NDH-1S) likely reflected a response to this perturbed ratio. Consistent with this was increased transcript abundance of genes encoding carboxysome structural proteins and carbonic anhydrase. Interestingly, the transition to pH 10 resulted in increased abundance of transcripts of photosystem II genes encoding extrinsic and low-molecular-weight polypeptides, although there was little change in photosystem I gene transcripts

Inelastic Neutron Scattering by Gaseous O2

The magnetic contributions to neutron diffraction by molecular oxygen have been studied both experimentally and theoretically. We extend the theoretical studies by performing a calculation of the magnetic interaction in the inelastic neutron cross section for gaseous O2. The magnetic inelastic cross section for O2 is significantly different from the nuclear inelastic cross section due to the lack of spherical symmetry in the magnetic‐moment distribution about each oxygen nucleus. It is expected from these results that the inelastic cross section for O2 will provide more information about the magnetic‐moment distribution than the angular distribution. We present representative calculations to indicate the size and nature of the magnetic contribution to the inelastic cross section.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71223/2/JCPSA6-49-2-890-1.pd

Hopping Transport in the Presence of Site Energy Disorder: Temperature and Concentration Scaling of Conductivity Spectra

Recent measurements on ion conducting glasses have revealed that conductivity spectra for various temperatures and ionic concentrations can be superimposed onto a common master curve by an appropriate rescaling of the conductivity and frequency. In order to understand the origin of the observed scaling behavior, we investigate by Monte Carlo simulations the diffusion of particles in a lattice with site energy disorder for a wide range of both temperatures and concentrations. While the model can account for the changes in ionic activation energies upon changing the concentration, it in general yields conductivity spectra that exhibit no scaling behavior. However, for typical concentrations and sufficiently low temperatures, a fairly good data collapse is obtained analogous to that found in experiment.Comment: 6 pages, 4 figure

How useful are building energy models for policy? A UK perspective

Energy demand models are central to the efforts of many governments to reduce carbon emissions from buildings. The lack of empirical research to ensure the appropriate use of predictions from the models has implications for building regulations and evaluating policy initiatives. We present three recent examples from the UK that highlight challenges: the discovery of a heat by-pass in party walls, trends in household gas consumption and the impact of condensing boilers, and inter-model variation in the non-domestic sector. We emphasise and contrast the approach of health sciences to support policy, and suggest that a far more systematic and integrated approach between empirical research, model development, and policy evaluation is needed

Peripheral hearing loss reduces the ability of children to direct selective attention during multi-talker listening

Restoring normal hearing requires knowledge of how peripheral and central auditory processes are affected by hearing loss. Previous research has focussed primarily on peripheral changes following sensorineural hearing loss, whereas consequences for central auditory processing have received less attention. We examined the ability of hearing-impaired children to direct auditory attention to a voice of interest (based on the talker’s spatial location or gender) in the presence of a common form of background noise: the voices of competing talkers (i.e. during multi-talker, or “Cocktail Party” listening). We measured brain activity using electro-encephalography (EEG) when children prepared to direct attention to the spatial location or gender of an upcoming target talker who spoke in a mixture of three talkers. Compared to normally-hearing children, hearing-impaired children showed significantly less evidence of preparatory brain activity when required to direct spatial attention. This finding is consistent with the idea that hearing-impaired children have a reduced ability to prepare spatial attention for an upcoming talker. Moreover, preparatory brain activity was not restored when hearing-impaired children listened with their acoustic hearing aids. An implication of these findings is that steps to improve auditory attention alongside acoustic hearing aids may be required to improve the ability of hearing-impaired children to understand speech in the presence of competing talkers