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Biomedical subjects

A Burton

Publications and source records attributed to A Burton.

18 recordsLinked to original sources
PubMed1991

Interhemisphere transfer in males and females.

Sex differences in the speed of interhemisphere transfer of visual information were assessed by means of a modified version of a task on which Potter and Graves (1988) have recently reported significantly lower error rates in females. The main aim was to examine the effect of including a control condition in which stimuli are presented centrally. In the light of their results, it was predicted that any advantage to females would be restricted to the peripheral condition since central presentations do not necessarily require interhemisphere transfer. Response latencies and errors were measured. No interaction between sex and position of presentation was found to occur. It is suggested that the lower error rates observed by Potter and Graves in females may have been the result of sex differences in speed-error trade off rather than in interhemisphere transfer.

Adolescent↗
PubMed1990

Hemisphere priming through practice in a musical chords task.

In a study of selective hemisphere activation, the performance of 30 subjects given either a "local" or "global" priming activity before and after a monoaurally presented chord analysis task was compared with an unprimed control group. The hypothesis was that ear advantage scores on the chords task would show increased left hemisphere involvement following local priming and increased right hemisphere involvement following global priming. The results failed to support this hypothesis. All subjects, however, regardless of priming condition, showed a very strong practice effect represented by a shift from a weak initial left ear (right hemisphere) advantage towards a significant right ear (left hemisphere) advantage (P less than 0.00006). The findings suggest that although the local/global priming activity did not lead to selective hemisphere activation, repeated exposure to the chords task resulted in increased use of analytic left hemisphere processing strategies as subjects became familiar with its processing requirements.

Adolescent↗
PubMed1990

Attitudes toward smoking in 7- to 9-year-old children.

This study reports the results of a survey on smoking of 214 children aged 7 to 9 years and 182 children aged 15 to 17 years. It was found that 27.1% of the younger group and 79.5% of the older group had tried to smoke a cigarette (even if just a few puffs). The frequency of continued smoking, as expected, was much greater for the older group, with 55.1% of older smokers compared to 0.9% of younger smokers having puffed during the last 4 weeks. The attitudes of subjects to smoking were generally negative although smokers' attitudes were more positive. The effects of parental smoking habits and attitudes on the subject's decision to smoke were considered and seen to be significant. The need for a health education program aimed at the young who have not established a smoking pattern is suggested.

Adolescent↗
PubMed1989

Mode of processing and hemisphere differences in the judgement of musical stimuli.

The relationship between processing strategy and ear asymmetry was examined in two experiments in which subjects were required to make judgements about monoaurally presented musical chords. In the first experiment, subjects without musical training showed a significant left ear advantage while in those with musical training a significant shift towards a right ear advantage was observed. Performance on the Embedded Figures Test (EFT) suggested a strong relationship between analytic processing style and right ear advantage which was significant in the musician groups. The effect of musical training status on ear asymmetry continued to be significant when the scores were adjusted for analytic processing. There was also a clear relationship between self-reported listening strategies and direction of ear asymmetry, with musicians generally reporting a much greater use of analytic strategies. The second experiment failed to demonstrate a significant influence of explicit instructions in how to carry out a chords task on the direction of ear advantages in musically untrained subjects. The results partially confirm earlier studies comparing subjects with and without musical training, and extend them by demonstrating a clear relationship between ear advantage and a separate measure of processing strategy. The findings of the second experiment, however, do not support clearly the hypothesis that differences in ear asymmetry are produced through the use of different processing strategies.

Adolescent↗
PubMed1989

Stimulation by 17 alpha-hydroxyprogesterone of glycoprotein and glycosaminoglycan synthesis in human placenta in vitro.

The incorporation of 14C-glucosamine into glycoproteins (GP) and glycosaminoglycans (GAG), of 3H-leucine into protein, and the hexuronic acid (HA) content of polymerized GAG was determined in incubated placental tissue. In placentae of earlier gestational age (GA), incorporation of 14C-glucosamine was 2.6 times greater than other at 38-39 weeks GA. 19 of 26 placentae at 38-39 weeks GA responded by one or more parameters when incubated with 0.5-3 microM 17 alpha-OH-progesterone (17OHP). Those which did not respond were all of earlier GA; the placental content of GAG decreased in these from 31.1 +/- 1.8 nmol HA/mg protein to 16.4 +/- 1.5 nmol in placentae of GA 38-39 weeks. In the latter, 17OHP increased GAG by 42.5% to 24.4 +/- 2.5 nmol HA/mg protein in a 2-hour incubation. Progesterone, oestriol, cortisol and testosterone were without effect. It is concluded that synthesis of placental GAG decreases toward the end of gestation, but can be increased by 17OHP specifically. This indicates that 17OHP is a biologically active steroid and might have a role in maintaining placental function.

17-alpha-Hydroxyprogesterone↗
PubMed1979

The effects of social reinforcement on dominant and dependent mildly intellectually handicapped school-leavers.

The aim of this study was to replicate Exline & Messick's (1967) study of eye-contact interview behaviour with college students on a group of mildly intellectually handicapped students. Twenty subjects (mean CA 14.02 years, SD 0.45 years, mean IQ 72.0, SD 7.6) attending a metropolitan school for the mildly mentally handicapped were classified as dominant or dependent by teacher ratings and sociogram analysis. They were given large or small amounts of reinforcement for eye-contact when interviewed by their teacher. Although the study failed to replicate some of Exline & Messick's findings, results indicated a feedback rather than reward model in explaining the effects of social reinforcement on eye-contact in interviews. Implications for communication training for such intellectually handicapped students is discussed.

Adolescent↗
PubMed1975

Natural infections of Richardson's ground squirrels with western equine encephalomyelitis virus, Saskatchewan, Canada, 1964-1973.

A survey (1964-1973) was conducted on naturally occurring western equine encephalomyelitis (WEE) virus infections of Richardson's ground squirrels (RGS) in agricultural areas of Saskatchewan. The survey included both serology and virus isolation attempts on live-trapped wild squirrels. Throughout the study, seropostive squirrels were found in the known enzootic regions of the province each summer. The infections rate was high (11.6% of 250) in the epidemic year of 1965 and low (less than 2% of 681) in the subsequent non-epidemic years. The maximal seasonal prevalence of seropositive RGS coincided with the time when the squirrel population and aedine mosquito abundance reached their seasonal peaks. Five virus isolations were obtained from the blood and brains of naturally infected squirrels. All isolations were from squirrels collected in June. The early seasonal infections in squirrels could provide a source of virus for Culex tarsalis, the epidemic vector. In view of their abundance in the enzootic agricultural areas and the high annual population turnover, the RGS may play an important role in the natural history of WEE virus in the Canadian prairies.

Animals↗