The right information may matter more than frequency-place alignment: Simulations of frequency-aligned and upward shifting cochlear implant processors for a shallow electrode array insertion

Objective: It has been claimed that speech recognition with a cochlear implant is dependent on the correct frequency alignment of analysis bands in the speech processor with characteristic frequencies (CFs) at electrode locations. However, the use of filters aligned in frequency to a relatively basal electrode array position leads to significant loss of lower frequency speech information. This study uses an acoustic simulation to compare two approaches to the matching of speech processor filters to an electrode array having a relatively shallow depth within the typical range, such that the most apical element is at a CF of 1851 Hz. Two noise-excited vocoder speech processors are compared, one with CF-matched filters, and one with filters matched to CFs at basilar membrane locations 6 mm more apical than electrode locations.Design: An extended crossover training design examined pre- and post-training performance in the identification of vowels and words in sentences for both processors. Subjects received about 3 hours of training with each processor in turn.Results: Training improved performance with both processors, but training effects were greater for the shifted processor. For a male talker, the shifted processor led to higher post-training scores than the frequency-aligned processor with both vowels and sentences. For a female talker, post-training vowel scores did not differ significantly between processors, whereas sentence scores were higher with the frequency-aligned processor.Conclusions: Even for a shallow electrode insertion, we conclude that a speech processor should represent information from important frequency regions below 1 kHz and that the possible cost of frequency misalignment can be significantly reduced with listening experience

Perceptual adaptation by normally hearing listeners to a simulated "hole" in hearing

Simulations of cochlear implants have demonstrated that the deleterious effects of a frequency misalignment between analysis bands and characteristic frequencies at basally shifted simulated electrode locations are significantly reduced with training. However, a distortion of frequency-to-place mapping may also arise due to a region of dysfunctional neurons that creates a "hole" in the tonotopic representation. This study simulated a 10 mm hole in the mid-frequency region. Noise-band processors were created with six output bands (three apical and three basal to the hole). The spectral information that would have been represented in the hole was either dropped or reassigned to bands on either side. Such reassignment preserves information but warps the place code, which may in itself impair performance. Normally hearing subjects received three hours of training in two reassignment conditions. Speech recognition improved considerably with training. Scores were much lower in a baseline (untrained) condition where information from the hole region was dropped. A second group of subjects trained in this dropped condition did show some improvement; however, scores after training were significantly lower than in the reassignment conditions. These results are consistent with the view that speech processors should present the most informative frequency range irrespective of frequency misalignment. 0 2006 Acoustical Society of America

First Year Projects and Activities of the Environmental Remote Sensing Applications Laboratory (ERSAL)

Activities, pilot projects, and research that will effectively close the gap between state-of-the-art remote sensing technology and the potential users and beneficiaries of this technological and scientific progress are discussed in light of the first year of activity. A broad spectrum of resource and man-environment problems are described in terms of the central thrust of the first-year program to support land use planning decisions with information derived from the interpretation of NASA highlight and satellite imagery

Discriminating coastal rangeland production and improvements with computer aided techniques

The feasibility and utility of using satellite data and computer-aided remote sensing analysis techniques to conduct range inventories were tested. This pilot study was focused over a 250,000 acre site in Galveston and Brazoria Counties along the Texas Gulf Coast. Rectified enlarged aircraft color infrared photographs of this site were used as the ground truth base. The different land categories were identified, delineated, and measured. Multispectral scanner (MSS) bulk data from LANDSAT-1 was received and analyzed with the Image 100 pattern recognition system. Features of interest were delineated on the image console giving the number of picture elements classified; the picture elements were converted to acreages and the accuracy of the technique was evaluated by comparison with data base results for three test sites. The accuracies for computer aided classification of coastal marshes ranged from 89% to 96%

The physical activity experiences of men with serious mental illness: Three short stories

Objectives: Although a considerable amount of research has explored the effects of physical activity on mental health, the voices of people with mental illness have been largely excluded from published reports. Through this study we aim to foreground service users' voices in order to shed light on the personal and subjective nature of the relationship between physical activity and serious mental illness (SMI). Methods: An interpretive case study approach was used to explore in depth the physical activity experiences of three men with SMI. Creative analytic practice was used to write three creative non-fictions which, as first-person narratives, foreground the participants' voices. Results: We present three short stories in an effort to communicate participants' personal and subjective experiences of physical activity in an accessible, engaging, and evocative manner. We hope to: (i) provide potentially motivating physical activity success stories for others who live with SMI; (ii) increase awareness among mental health professionals of the possibilities of physical activity; and (iii) provide an empathetic understanding of possibilities and problems of living with SMI which may help challenge the stigma surrounding mental illness. Conclusions: For us, the stories communicate the diversity and difference inherent in the ways men with SMI experience physical activity. We reflect on how the short story form allows these differences to be preserved and respected. We resist making further interpretations of the stories preferring instead to encourage the reader to form her or his own conclusions. © 2007 Elsevier Ltd. All rights reserved

An electric-field representation of the harmonic XY model

The two-dimensional harmonic XY (HXY) model is a spin model in which the classical spins interact via a piecewise parabolic potential. We argue that the HXY model should be regarded as the canonical classical lattice spin model of phase fluctuations in two-dimensional condensates, as it is the simplest model that guarantees the modular symmetry of the experimental systems. Here we formulate a lattice electric-field representation of the HXY model and contrast this with an analogous representation of the Villain model and the two-dimensional Coulomb gas with a purely rotational auxiliary field. We find that the HXY model is a spin-model analogue of a lattice electric-field model of the Coulomb gas with an auxiliary field, but with a temperature-dependent vacuum (electric) permittivity that encodes the coupling of the spin vortices to their background spin-wave medium. The spin vortices map to the Coulomb charges, while the spin-wave fluctuations correspond to auxiliary-field fluctuations. The coupling explains the striking differences in the high-temperature asymptotes of the specific heats of the HXY model and the Coulomb gas with an auxiliary field. Our results elucidate the propagation of effective long-range interactions throughout the HXY model (whose interactions are purely local) by the lattice electric fields. They also imply that global spin-twist excitations (topological-sector fluctuations) generated by local spin dynamics are ergodically excluded in the low-temperature phase. We discuss the relevance of these results to condensate physics.Comment: 13 pages, 10 figure

Topological-sector fluctuations and ergodicity breaking at the Berezinskii-Kosterlitz-Thouless transition

The Berezinskii-Kosterlitz-Thouless (BKT) phase transition drives the unbinding of topological defects in many two-dimensional systems. In the two-dimensional Coulomb gas, it corresponds to an insulator-conductor transition driven by charge deconfinement. We investigate the global topological properties of this transition, both analytically and by numerical simulation, using a lattice-field description of the two-dimensional Coulomb gas on a torus. The BKT transition is shown to be an ergodicity breaking between the topological sectors of the electric field, which implies a definition of topological order in terms of broken ergodicity. The breakdown of local topological order at the BKT transition leads to the excitation of global topological defects in the electric field, corresponding to different topological sectors. The quantized nature of these classical excitations, and their strict suppression by ergodicity breaking in the low-temperature phase, afford striking global signatures of topological-sector fluctuations at the BKT transition. We discuss how these signatures could be detected in experiments on, for example, magnetic films and cold-atom systems.Comment: 11 pages, 6 figure

BLACKBIRD DEPREDATIONS IN ANIMAL INDUSTRY: POULTRY RANGES AND HOG LOTS

I\u27m going to move over onto poultry ranges, turkey ranges and hog farms where we have species of birds such as the herring gull, the pigeon, the starling and English sparrow. As a rule, these birds travel relatively great distances from roosts and loafing areas out to the feeding ranges. And why shouldn\u27t they? There is ample high energy food available and usually lack of human disturbance. So they frequent these places during the daylight hours. Actually the losses from these operations are pretty hard to evaluate. Sometimes it is direct, the farmer feels the impact; other times it\u27s indirect. We do suspect diseases being carried onto the poultry range or hog farm by these wild birds. Let\u27s examine these four species and find where the damage occurs. I\u27ll tell you what we are doing to reduce this damage. The herring gull, in this part of the country (midwest-Great Lakes) and also along the Atlantic Coast, is increasing in numbers by leaps and bounds. Also the herring gull has become a bum. In its original environment, it foraged along the shoreline and behind fishing vessels and it did very well. Now he\u27s turned into a bum, because we\u27ve turned into bums. Our unsanitary ways of managing dumps and hog lots have made things ideal for the herring gull and he\u27s adjusted very nicely to these conditions. Consequently, he\u27s moved onto hog lots where they cook garbage and dump it onto the land. He also follows garbage feeding trucks through the hog lots where they dump cooked garbage into the feeding troughs. The gull is taking food from the hogs and from the farmer. Also because he visits the dump, then goes to the hog lot, he is also carrying such transmissible diseases as hog cholera. Also herring gulls are suspected of carrying TGE (transmissible gastroenteritis). Because they perch upon farm buildings, gulls are also adding to structural deterioration