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Biomedical subjects

R Cowie

Publications and source records attributed to R Cowie.

At least 19 recordsLinked to original sources
PubMed2005

ASR for emotional speech: clarifying the issues and enhancing performance.

There are multiple reasons to expect that recognising the verbal content of emotional speech will be a difficult problem, and recognition rates reported in the literature are in fact low. Including information about prosody improves recognition rate for emotions simulated by actors, but its relevance to the freer patterns of spontaneous speech is unproven. This paper shows that recognition rate for spontaneous emotionally coloured speech can be improved by using a language model based on increased representation of emotional utterances. The models are derived by adapting an already existing corpus, the British National Corpus (BNC). An emotional lexicon is used to identify emotionally coloured words, and sentences containing these words are recombined with the BNC to form a corpus with a raised proportion of emotional material. Using a language model based on that technique improves recognition rate by about 20%.

Emotions↗
PubMed2003

PicSOr: an objective test of perceptual skill that predicts laparoscopic technical skill in three initial studies of laparoscopic performance.

BACKGROUND: Laparoscopic surgery requires surgeons to infer the shape of 3-D structures, such as the internal organs of patients, from 2-D displays on a video monitor. Recent evidence indicates that the issue is not resolved by the use of contemporary 3-D camera systems. It is therefore crucial to find ways of measuring differences in aptitude for recovering 3-D structure from 2-D images, and assessing its impact on performance. Our aim was to test empirically for a relationship between laparoscopic ability and the perceptual skill of recovering information about 3-D structures from 2-D monitor displays. METHODS: Participants in three studies completed a simulated laparoscopic cutting task as well as the Pictorial Surface Orientation (PicSOr)3 Test. In studies 1 (n = 48) and 2 (n = 32) both groups were laparoscopic novices, and in study 3 (n = 34) 18 of the participants were experienced laparoscopic surgeons. FINDINGS: All three studies showed that PicSOr consistently predicted the laparoscopic performance of participants on the laparoscopic cutting task (study 1, r = 0.5, p < 0.0003; study 2, r = 0.5, p < 0.004; and study 3, r = 0.42, p = 0.017). Furthermore, it was also a significant predictor of laparoscopic surgeons' performance (r = 0.54, p = 0.047). INTERPRETATIONS: This is the first objective perceptual psychometric test to reliably predict laparoscopic technical skills. PicSOr provides a tool for assessing which trainees have the potential to learn minimal access surgery.

Adult↗
PubMed2002

Prosodic characteristics of skilled reading: fluency and expressiveness in 8-10-year-old readers.

Statistical methods of describing prosody were used to study fluency, expressiveness and their relationship among 8-10-year-old readers. 67 children were rated on fluency and expressiveness. The two were partially independent in the full sample: expressiveness rarely occurred without fluency, but fluency occurred without expressiveness. A balanced subsample of 24 was selected for closer instrumental and statistical analysis. There were robust relationships between fluency and measures associated with temporal organization.between expressiveness and variables associated with pitch mobility; and Interactions indicated that the relationships were not simple. Differences between groups depended on sentence content and position-expressive readers distinguished sentences more sharply according to content, and the groups diverged on some measures as the passage progressed. Also, measures associated primarily with either fluency or expression often showed secondary sensitivity to the other: temporal organization was associated with fluency, but worsened over time among inexpressive readers; and readers who were both fluent and expressive were distinctive in several respects. Some measures offer a basis for rules aimed at assigning individuals to skill categories, particularly the magnitude of pitch movements and reading time per syllable. The rules distinguish well among readers who were either at one of the extremes of skill, or fluent but inexpressive; it is harder to discriminate among the other readers (who have mixed skill patterns). The effects suggest psychological hypotheses about the underlying mechanisms.

Child↗
PubMed2002

The epidemiology of tuberculosis among foreign-born persons in Alberta, Canada, 1989-1998: identification of high risk groups.

BACKGROUND: To date, there have been no comprehensive epidemiological studies in Canada of the incidence rates of tuberculosis among foreign-born persons. Accurate rate estimates are needed to develop cost-effective strategies for the prevention, control, and ultimate elimination of tuberculosis. METHODS: Most new immigrants to Canada settle in one of four provinces: Ontario, British Columbia, Quebec and Alberta. Data from the provincial reporting system for tuberculosis, from Statistics Canada censuses and population estimates of Treaty Status Indians provided by the Department of Indian and Northern Affairs Canada, were used to estimate the rate of tuberculosis in Alberta's Canadian-born and foreign-born population between 1989 and 1998. RESULTS: Age-adjusted tuberculosis case rates per 100,000 person-years were 19.4 and 61.9 in the foreign-born and Canadian-born Treaty Indians-approximately 10 times and 30 times, respectively, higher than the rate in the remainder of the Canadian-born population (2.1/100,000 person-years). Age-specific rates in male and female foreign-born persons were highest at ages 15-34 and > or = 65 years, whereas rates in Canadian-born non-Treaty and Treaty males and females increased incrementally, with a single peak at > or = 65 years. Tuberculosis case rates in the foreign-born varied significantly according to World Bank region and country of birth. By far the highest rates were seen in immigrants to Canada from Asia, in particular Vietnam, the Philippines, China, Hong Kong and India. Most (90%) tuberculosis patients from these countries had not been identified as requiring medical surveillance in Canada after arrival. CONCLUSION: Immigrants to Alberta from Asia and Treaty Status Indians are at high risk for tuberculosis. Physicians in Alberta who care for foreign-born persons should be aware that their patients are at increased risk for tuberculosis, even if they have been medically cleared during the legal immigration process.

Adolescent↗
PubMed1998

Measurement and modelling of perceived slant in surfaces represented by freely viewed line drawings.

Simple pictures under everyday viewing conditions evoke impressions of surfaces oriented in depth. These impressions have been studied by measuring the slants of perceived surfaces, with probes (rotating arrowheads) designed to respect the distinctive character of depicted scenes. Converging arguments indicated that the perceived orientation of the probes was near theoretical values. A series of experiments showed that subjects formed well-defined impressions of depicted surface orientation. The literature suggests that perceived objects might be 'flattened', but that was not the general rule. Instead, both mean slant and uncertainty fitted models in which slant estimates are derived in a relatively straightforward way from local relations in the picture. Simplifying pictures tended to make orientation estimates less certain, particularly away from the natural anchor points (vertical and horizontal). The shape of the object affected all aspects of the observed-object/percept relationship. Individual differences were large, and suggest that different individuals used different relationships as a basis for their estimates. Overall, data suggest that everyday picture perception is strongly selective and weakly integrative. In particular, depicted slant is estimated by finding a picture feature which will be strongly related to it if the object contains a particular regularity, not by additive integration of evidence from multiple directly and indirectly relevant sources.

Computer Graphics↗
PubMed1998

Variation among nonclinical subjects on a line-bisection task.

Absence of leftward bias in a line-bisection task is often used as a clinical hemispheric indicator, but the effect is not uniform in a normal population. Sex, handedness, and strategy variables affect the strength and direction of any bias.

Dominance, Cerebral↗
PubMed1997

Pulmonary function abnormalities in patients with ulcerative colitis.

OBJECTIVES: We hypothesized that abnormalities in pulmonary function are present in subjects with ulcerative colitis (UC). Our primary objectives were (1) to determine the frequency of pulmonary abnormalities in a sample of subjects with UC, and (2) to compare UC subjects with abnormal pulmonary function tests (PFT) with those who have normal PFT in terms of smoking behavior and history of preexisting pulmonary disease. METHODS: We selected 100 consecutive UC subjects from the index of subjects currently attending the University of Calgary clinics. Sixty-six were eligible. Fifty-five (83%) agreed to participate. RESULTS: PFT abnormalities were found in 30 (55%) subjects. Abnormal PFT could not be predicted by current or past smoking status, family history of respiratory diseases, occupational history, or current medication status. CONCLUSIONS: (1) PFT abnormalities were detected in half of the subjects. (2) Smoking status was not predictive of these abnormalities.

Adult↗
PubMed1995

A structure-from-motion scheme that looks for parallels, and its implications for apparent reversals in rotating trapezia.

Apparent reversals in rotating trapezia have been regarded as evidence that human vision favours methods which are heuristic or form dependent. However, the argument is based on the assumption that general algorithmic methods would avoid the illusion, and that has never been clear. A general algorithm for interpreting moving parallels has been developed to address the issue. It handles a considerable range of stimuli successfully, but finds multiple interpretations in situations which correspond closely to those where apparent reversals occur. This strengthens the hypothesis that apparent reversals may occur when general algorithmic methods fail and heuristics are invoked as a stopgap.

Form Perception↗
PubMed1995

Thrombosis of the straight sinus complicating hormone replacement therapy.

Oral contraceptives have been implicated in the pathogenesis of dural venous thrombosis. No similar association has been confirmed between postmenopausal hormone replacement therapy and cerebral venous thrombosis, although one previous report in the literature has identified such a case. We present a further case of thrombosis of the straight sinus in a patient on hormone replacement therapy (HRT) and suggest that dural sinus thrombosis is a rare, but dangerous complication of HRT.

Cerebral Angiography↗
PubMed1995

Comparison of Diskus inhaler, a new multidose powder inhaler, with Diskhaler inhaler for the delivery of salmeterol to asthmatic patients. Canadian Study Group.

Administration of the long-acting beta 2-adrenoceptor agonist salmeterol from a new, easy-to-operate, multidose powder inhaler (Diskus) containing 60 sealed doses in a foil strip has been compared with administration from a Diskhaler inhaler in a multicenter, double-blind, double-dummy, parallel-group study. Asthmatic patients taking anti-inflammatory treatment, with baseline FEV1 > or = 60% and < or = 90% predicted were treated for 4 weeks with salmeterol 50 micrograms twice daily from either the Diskus or Diskhaler inhaler. The two treatments were equivalent (90% CLs for the difference in mean morning PEFR: -2.2, 8.7 L/min). The Diskus inhaler was rated easier to use and was preferred by more patients than the Diskhaler inhaler (73% vs. 15%).

Adolescent↗
PubMed1992

Rectangles may appear to reverse like trapezia when they rotate at an uneven rate.

A 1983-1985 theory by Mitchell and Power predicts that, when rotating rectangles undergo certain kinds of speed fluctuation, they should appear to reverse just as trapezia do. The prediction is partially confirmed. One of two 'mimic' rectangles underwent apparent reversals more often than a control rectangle undergoing even rotation and in the same places as rotating trapezia. However, its reversal frequency was less than those of the trapezia, and a second 'mimic' slowed an inappropriate distribution of reversals round the cycle. These anomalies call for some modification to Mitchell and Power's theory, but minor qualifications may be sufficient.

Adult↗
PubMed1989

Rotating trapezia which appear luminous and transparent during reversals.

If a rotating trapezium is lit by a visible source at one side, it sometimes reflects light to the observer and sometimes appears dark. This provides information about its orientation which is relevant to the suppression of apparent reversals. Marked suppression does occur if the light is between the observer and the object, but in other cases novel phenomena arise. The onset of light may precipitate corrections, ie discontinuous shifts from an illusory percept to a veridical one. At certain stages the object may also appear to be transparent and luminous, particularly if a bar has been passed through it: the bar then appears to be visible through the object. The effects illustrate the limited use vision makes of seemingly excellent sources of information, but they also indicate that the problem may lie in misplaced sophistication rather than crudity.

Adult↗
PubMed1983

Stereotactic removal of intracranial foreign bodies: review and case report.

A 13-year-old boy presented himself with an airgun injury with a track from an entry wound in the left temporal region to the right thalamic pulvinar. The patient made a good recovery following stereotactic removal of the pellet. The literature is reviewed and the indications for stereotactic removal of intracranial foreign bodies discussed.

Adolescent↗
PubMed1983

Transoral-transclival clipping of a midline vertebral artery aneurysm.

The technical advantages and possible indications for a transoral-transclival approach for low midline posterior circulation aneurysms are discussed. A case report using such a route is described. The prognosis of untreated vertebro-basilar aneurysms is briefly discussed.

Basilar Artery↗