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B A Wright

Publications and source records attributed to B A Wright.

At least 55 records · Page 3Linked to original sources
PubMed1990

Comodulation detection differences with multiple signal bands.

Detection thresholds were determined for signals consisting of one, two, or five noise bands embedded in eight "cue" bands. All of the noise bands were 100 Hz wide. The center frequencies of the signal bands ranged from 1250-3250 Hz in 500-Hz steps, and those of the cue bands ranged from 500-4000 Hz in 500-Hz steps. The multiple-band signals either all had the same temporal envelope, or all had different temporal envelopes. Similarly, the cue bands either all had the same temporal envelope or all had different temporal envelopes. In separate listening conditions, signal thresholds were determined for various combinations of the temporal envelope patterns of the signal and cue bands. The results were analyzed both in terms of differences in threshold across listening conditions, and in terms of changes in threshold within a listening condition, as the number of signal bands was increased. For both the single- and multiple-band signals, performance was best when the signal band(s) had a different envelope from the common envelope of the cue bands, and performance was worst when either the cue bands all had different envelopes, or the signal and cue bands all shared the same envelope. The thresholds of the multiple-band signals were better fitted by an independent-thresholds model than by a statistical-summation model. However, neither model predicted thresholds uniformly well in all listening conditions. The results are discussed in terms of both "within-channel" and "across-channel" models.

Acoustic Stimulation↗
PubMed1990

Uncertainty about the correlation among temporal envelopes in two comodulation tasks.

The threshold of a 1250-Hz tonal signal was measured in the presence of five noise bands (each 50 Hz wide, centered at 850, 1050, 1250, 1450, and 1650 Hz) under five conditions of uncertainty about the waveform type ("correlated" or "uncorrelated"), and/or the specific waveform sample to be presented. The waveform type was correlated when the temporal envelopes of all of the noise bands were the same, and was uncorrelated when the temporal envelope of the band centered on the signal differed from the common envelope of the other bands. At the low-uncertainty end of the continuum of conditions, the same waveform type was presented throughout an entire block of trials, and, in addition, the same waveform sample was presented on the two observation intervals of a single trial (but changed across trials). At the high-uncertainty end of the continuum, both the waveform type and the waveform sample were chosen at random for every observation interval. Threshold estimates obtained from trials in which both observation intervals contained the same waveform type were not affected by uncertainty about the waveform sample within a trial, nor by uncertainty about the waveform type introduced across trials. Thus the comodulation masking release, or CMR (the difference in the thresholds obtained with the uncorrelated and correlated waveforms), calculated from these types of trials was robust across all of the uncertainty conditions. However, on those trials in which one correlated interval and one uncorrelated interval were paired, threshold estimates were influenced by a bias for listeners to choose the uncorrelated interval as the signal interval, whether or not it actually contained the signal. This bias reveals the importance of recognizing the contribution of the nonsignal interval in experiments involving masker uncertainty. Parallel results were obtained using the comodulation detection difference (CDD) task. In some conditions, marked individual differences were observed.

Adolescent↗
PubMed1990

Temporal decline of masking and comodulation detection differences.

Comodulation detection differences (CDDs) were studied using flanking bands that were either gated simultaneously with the signal band (burst) or gated at varying times prior to signal onset (fringed). Used for these experiments were a signal band centered at 1250 Hz and four flanking bands centered at 450, 850, 1650, and 2050 Hz; all bands were 100 Hz wide. In different conditions, the temporal envelope of the signal band was either the same as (correlated), or different from (uncorrelated), the common envelope of the four flanking bands, or the temporal envelopes of all of the bands were different (all-uncorrelated). For 8 of the 13 listeners, signal detectability improved by as much as 25 dB as the temporal fringe of the flanking bands was increased from 5 to about 700 ms. This temporal decline of masking was similar, but not identical, for the correlated, uncorrelated, and all-uncorrelated conditions. Results of this sort are reminiscent of several related findings that have been attributed to auditory adaptation or enhancement, or to a temporally developing critical-band filter. The other 5 of the 13 listeners were generally more sensitive than the majority, and they showed little or no improvement in detectability as fringe duration was varied. Large individual differences of this sort are not uncommon in the adaptation and comodulation literatures. As signal duration was changed from 50 to 240 ms, temporal integration was less in the correlated condition than in the uncorrelated condition, thereby producing a larger CDD with the longer signal. When the fringe followed the observation interval instead of preceding it, the results were equivocal because detectability improved for the majority of subjects and worsened for the minority. In follow-up experiments, different subsets of these four flanking bands were used. When temporal gaps of varying duration were inserted into the flanking band(s) immediately prior to the observation intervals, it was found that a temporal gap as long as 355 ms was not sufficient to reset the mechanisms underlying the temporal decline of masking.

Adult↗
PubMed1990

Frequent fallers. Leading groups to identify psychological factors.

CNAs might be good leaders for groups of frequent fallers for several reasons, two of which are that they provide hands-on care and they know the residents well. Residents who fall frequently do not see themselves as persons who fall; they slip, trip, or slide. Single fallers explore ways to prevent another fall. Residents attempting to "do for themselves" and thus maintain their highly-prized independence is a factor contributing to falls. Preservation of autonomy and self-esteem are co-factors. Denial and independence in the faller need to be identified, supported as strengths, and incorporated into a resident's plan of care.

Accident Proneness↗
PubMed1990

Lipoid pneumonia.

The most common sources for lipids producing radiographic or clinical evidence of disease in the lungs are endogenous lipids and inhaled (exogenous) mineral oil. Endogenous lipoid pneumonia arises when lung tissue breaks down distal to an obstructed airway leading to the release of cholesterol and other lipids, producing airspace disease. Exogenous lipoid pneumonia occurs most frequently in the elderly following habitual mineral oil use. Many patients have no specific predisposing cause for aspiration of the ingested mineral oils. Symptoms, found in only half of the patients reviewed, include chronic cough and sputum production. Radiographically, the lesions are usually ill-defined radiopacities that mimic carcinoma of the lung. The inhaled mineral oil incites a foreign-body reaction, producing a granuloma with multinucleated foreign-body giant cells and fibrosis surrounding lipid droplets. Diagnostic strategies such as sputum examination for lipids and transthoracic needle aspiration are discussed. These procedures may help to avoid thoracotomy in elderly, often debilitated patients with lipoid pneumonia.

Aged↗
PubMed1989

Extension of Heider's ideas to rehabilitation psychology.

Fritz Heider received the Psychological Science Gold Medal Award at the 1987 Annual Convention of the American Psychological Association. This article was prepared for the symposium honoring his contributions. It shows the power of his conceptual framework as a basis for systematizing attitude-change attempts involving disability, as well as the need for affirmative action. The analysis involves such concepts as balance, unit-forming factors, sentiment, and ought.

Attitude↗
PubMed1989

Isolation of enterovirus and reovirus from sewage and treated effluents in selected Puerto Rican communities.

Sewage treatment plant effluents were surveyed for viral contributions to gastroenteritis outbreaks in Puerto Rico. Of the 15 sewage treatment plants studied, all discharged their effluents upstream from water treatment plant intakes. No base-line data on the degree of viral challenge to these sewage treatment plants or the subsequent reduction of viruses before discharge existed. Enterovirus counts were generally much higher than those found in the continental United States. At four plants, viruses in the incoming sewage exceeded 100,000 PFU/liter, and one of these, a trickling filter plant, was discharging 24,000 PFU/liter to receiving waters. Virus identification showed that more than 80% of the enterovirus isolates were coxsackievirus B5. These overwhelming viral numbers pointed to defects in the sewage treatment processes. Without reasonable barriers to protect receiving waters, several of the downstream communities were using raw waters that posed extraordinary demands on the ability of their water treatment plants to supply virologically safe drinking water.

Enterovirus↗
PubMed1988

A comparison of recovery of virus from wastewaters by beef extract-Celite, ferric chloride, and filter concentration procedures.

An improved concentration method using sample volumes as large as 1500 ml has been developed to monitor for viruses in wastewaters. Non-precipitating dry beef extract powder is added to wastewater samples to give a 3% concentration and mixed until dissolved. This is followed by the addition of Celite as a virus adsorbent. By manipulating pH, viruses are eluted from the Celite in small volumes of phosphate buffer. This procedure was further tested without the aid of the Celite additives using a precipitating beef extract powder and substituting FeCl3 as an alternate reagent for the Celite. Comparison testing was also made with the currently recommended cartridge and disc filter procedures. In all cases, the non-precipitating beef extract-Celite method gave higher recovery rates in highly polluted waters.

Adsorption↗
PubMed1988

Optimization of suspended cell method and comparison with cell monolayer technique for virus assays.

The suspended cell technique for enumeration of viruses from environmental samples was evaluated in regards to the number of cells necessary per bottle or flask, contact time with virus prior to overlay, and number of viruses per sample for maximum enumeration, using 40-cm2 (6 oz) glass bottles or 25-cm2 plastic culture flasks. Optimum cell numbers were determined to be 4 x 10(7) cells for the 40-cm2 bottles and 2.0 x 10(7) cells for the 25-cm2 flasks. The optimum exposure time of virus to cells at 37 degrees C was 60 min with significantly higher recoveries with shaken mixtures as opposed to static mixtures. Upon comparing the suspended cell technique with that of the cell monolayer system, using two sets of environmental sewage sample concentrates, 62 of the 67 samples yielded an average of 5-8 times greater viral recoveries with the suspended cell procedure. Based on our data we feel that all environmental samples should be tested using the suspended cell procedure.

Culture Techniques↗
PubMed1987

Comodulation masking release in a forward-masking paradigm.

Waveforms that yield comodulation masking release (CMR) when they are presented simultaneously with a signal were used in a standard forward-masking procedure. The signal was a 25-ms sample of a 2500-Hz tone. The masker was a band of noise centered at 2500 Hz, 100 Hz in width, and 200 ms in duration. Presented with the masker were two or four cue bands, each 100 Hz wide and centered at various distances from the masker band. These cue bands either all had the same temporal envelope as the masker band (correlated condition) or their common envelope was different from that of the masker band (uncorrelated condition). In the initial experiments, (1) detectability of the tonal signal was 7-18 dB better when the masker band was accompanied by cue bands than when it was not--an effect that would be expected from past research on lateral suppression--but further, (2) the signal was about 3 dB more detectable in the correlated conditions than in the uncorrelated conditions. In follow-up experiments, these CMR-like differences between the correlated and uncorrelated conditions were substantially reduced (although not eliminated) by presenting a contralateral, wideband noise that was gated synchronously with the masker and/or cue bands. The implications are that the initial results were attributable in part to the "confusion effects" known to exist in certain temporal-masking situations, and that listeners are able to obtain greater information about the temporal extent of a masker band from correlated cue bands than from uncorrelated bands.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1986

Palatal swellings associated with multilesional disorders: report of cases.

Two cases with similar initial oral manifestations, i.e., solitary, unilateral soft tissue palatal swellings, were presented. These two cases represented separate and distinct conditions, multiple lipomas and neurofibromatosis. These conditions were reviewed briefly, together with tuberous sclerosis, as conditions in which both oral and multiple cutaneous nodules may be present.

Adult↗
PubMed1986

Optimization of the BGM cell line culture and viral assay procedures for monitoring viruses in the environment.

An in-depth study of the continuous cell line designated BGM is described herein, and recommendations are made for standardizing cell culture and viral assay procedures. Based on data gathered from a survey of 58 laboratories using this cell line, a research plan was developed that included the study of growth media, sera, NaHCO3 levels, culture bottles, cell concentration, overlay media, agar, virus infection conditions, and cell-dissociating agents. Additionally, a comparative virus isolation study with BGM cells and nine other cell types was conducted with 37 sewage samples collected from nine different geographic areas. The results of the study indicated that the BGM cell line is superior for virus isolation when compared with the other cell types and that certain media and additives tend to increase BGM cell sensitivity to a specific group of viruses. A standardized procedure for cultivation of BGM cells is described which provides a more effective enterovirus assay system.

Animals↗
PubMed1986

Recovery of viruses from water by a modified flocculation procedure for second-step concentration.

A reduction in virus recovery efficiencies stemming from a change in the commercial processing of powdered beef extract was reversed by the addition of Celite analytical filter aid. Supplementing beef extract with this silicate is recommended as a modification to the organic flocculation procedure for second-step concentration in monitoring for waterborne viruses. Considerable differences in virus recovery were found among lots of beef extract and Celite preparations; this indicates that the performance of each lot of these substances should be checked before use.

Animals↗
PubMed1986

The geriatric implications of fecal impaction.

Fecal impactions are a common problem in debilitated elderly people and may present as a life-threatening event. The atypical presentations of fecal impactions are not well-recognized, and the incidence, morbidity and mortality of fecal impactions in the elderly are largely unknown. Elderly debilitated people have reduced organ system reserve. An acute illness may worsen underlying chronic diseases. Fecal impactions may upset the fragile homeostasis of an elderly debilitated person. The signs and symptoms of fecal impaction may not be manifested in the gastrointestinal system; rather, the patient may present with circulatory, cardiac or respiratory symptoms. If the diagnosis of fecal impaction is unrecognized and untreated, signs and symptoms may progress, leading to death. The causes, mechanisms, appropriate history, physical examination, diagnostic techniques, therapy and prevention of fecal impactions in elderly people are presented.

Aged↗
PubMed1985

Adrenoleukodystrophy mimicking multiple sclerosis.

We report a 47 year old woman who was initially diagnosed as having multiple sclerosis. She has subsequently been found to be heterozygous for adrenoleukodystrophy (ALD). The female carrier state for ALD may be associated with intermittent symptoms and it is therefore important to consider ALD in patients diagnosed as multiple sclerosis.

Adrenoleukodystrophy↗
PubMed1985

Use of bituminous coal as an alternative technique for field concentration of waterborne viruses.

A filter system that sandwiches a bituminous coal preparation between two prefilters was comparable to those presently used to recover human viruses from large volumes of water. This filter was effective over a pH range of 3.0 to 7.0. Poliovirus type 1 recoveries from 100-liter seeded samples of Cincinnati tap water did not vary significantly when compared with those of identical samples processed through Filterite and Millipore filters. In studies with raw domestic sewage, virus recoveries were nearly identical from comparable samples filtered through coal and Millipore disk filters. Thus, the availability of coal makes this filter system an inexpensive analytical tool, especially in developing nations, for virus concentration.

Aluminum↗
PubMed1984

Recurrent calcifying odontogenic cyst.

This article reports a recurrence of a calcifying odontogenic cyst which occurred 5 years after the initial treatment. To date all recurrences of calcifying odontogenic cysts have been in elderly persons. The present recurrence was in an 11-year-old girl.

Child↗