Search PubMed⌕ Search

Biomedical subjects

I D Brown

Publications and source records attributed to I D Brown.

At least 19 recordsLinked to original sources
PubMed1997

Prospects for technological countermeasures against driver fatigue.

There are three reasons for giving serious consideration to technological countermeasures against driver fatigue: 1, fatigue is a persistent occupational hazard for professional drivers; 2, some professional drivers are under considerable pressure to reach their scheduled destination, in spite of feeling drowsy; 3, fatigue adversely affects an individual's ability to assess their own fitness to continue driving. However, there are two reasons for exercising caution in implementing technological countermeasures: 1, their reliability under real traffic conditions is largely unproven; 2, they could be used by unscrupulous drivers to support the continuation of journeys that should have been terminated because of human impairment. This paper draws on the findings of research into the origins, symptoms and development of human fatigue, and on recent research into driver-support systems, to assess the prospects for implementations of technological countermeasures against driver fatigue in the foreseeable future.

Accidents, Occupational↗
PubMed1994

Driver fatigue.

Psychological fatigue is defined as a subjectively experienced disinclination to continue performing the task at hand. It generally impairs human efficiency when individuals continue working after they have become aware of their fatigue. It does not depend on energy expenditure and cannot be measured simply in terms of performance impairment. The interacting causal contributions to fatigue are the length of continuous work spells and daily duty periods, time available for rest and continuous sleep, and the arrangement of duty, rest, and sleep periods within each 24-h cycle. Empirical evidence for the separate and combined effects of these factors on fatigue, performance decrement, and accident risk are briefly reviewed, and the implications of these findings for driving and road safety are considered, with particular reference to the professional driver. This study shows that fatigue is insufficiently recognized and reported as a cause of road accidents and that its effects stem largely from prolonged and irregular working hours, rather than simply from time spent at the wheel.

Accidents, Traffic↗
PubMed1993

The prevalence of depression in a high school population.

This study examined the prevalence of depression in a nonclinical adolescent population (N = 2,698) in a major Canadian city. The Beck Depression Inventory was administered to students in three secondary schools. An analysis of variance revealed significant main effects of age and gender. The percentage of students categorized as experiencing none to mild depression was contrasted with those experiencing moderate to severe depression. Overall, the results showed relatively low rates of severe or moderate depression in this population. The findings are discussed in the context of previous investigations.

Adolescent↗
PubMed1991

The initial use of a computer-controlled expert system in the treatment planning of Class II division 1 malocclusion.

A computer based expert system for providing orthodontic advice for Class II Division 1 malocclusion has been developed and evaluated. Treatment plans produced by the system for 31 non-prior approval cases drawn from material provided by the Dental Practice Board were compared with the treatments actually carried out by the practitioners. The shortcomings of the system are discussed.

Decision Trees↗
PubMed1989

Assessing one's own and others' driving ability: influences of sex, age, and experience.

Observational studies of drivers' involvements in dangerous situations suggest that young males drive differently from other road users. Studies of drivers' assessments of their own ability appear to show that they believe they drive better than their peers and that, while young males equate their ability with that of older male drivers, the latter group see themselves as superior to their younger counterparts but of equivalent ability to peers. It is unclear from previous studies what the influence of driving experience is on such assessments and, indeed, what female drivers feel about their ability. The present studies suggest that the widely reported tendency for people to overestimate their ability may be largely artifactual, that males and females describe their performance similarly, and that previously reported age differences disappear when driving experience is controlled. Among the differences that remain is the reported greater "recklessness" and comparative lack of "smoothness" of young males' driving. The implications of these findings for our understanding of risk assessment and acceptance are discussed.

Adult↗
PubMed1989

The closure of residual extraction spaces by means of traction screws: a report of two cases.

In those cases judged to be suitable for treatment by extractions in both arches and the use of upper removable appliances alone, the closure of excess residual space relies on mesial drift of the buccal segments. If opposing residual spaces are unequal in extent, there is a risk that space closure will be incomplete. Two cases are presented where a removable appliance was used to move a buccal segment mesially using a traction screw, and thereby close the excess residual space.

Adolescent↗
PubMed1988

Pieces of eight.

Explore the source record for details and available documents.

Adult↗
PubMed1985

Changes in lipid fluidity and fatty acid composition with altered culture temperature in Tetrahymena pyriformis-NT1.

Cultures of T. pyriformis-NT1 were grown at 20 degrees C (Tg 20 degrees C) and 38 degrees C (Tg 38 degrees C). G.L.C. analysis and D.P.H. fluorescence polarization measurements in extracted phospholipids indicated that there was increased saturation of fatty acids and relatively reduced fluidity as growth temperature was increased. Breakpoints occurred in the Arrhenius plots of fluorescence polarization at 16 degrees C for Tg 38 degrees C total extracted phospholipids and 9 degrees C for Tg 20 degrees C lipids.

Animals↗
PubMed1985

The effects of temperature upon the electrophysiological properties of Tetrahymena pyriformis-NT1.

Cells of Tetrahymena pyriformis--NT1 were cultured at 38 degrees C (Tg 38 degrees C) and 20 degrees C (Tg 20 degrees C) and their properties investigated over the range 0-40 degrees C. Tg 20 degrees C cells were viable in the range 3-33 degrees C and changes in their properties were readily reversible between 10 degrees C and 30 degrees C. Tg 38 degrees cells were viable in the range 40-10 degrees C and their property changes were immediately reversible in the range 40-23 degrees C. The I-V relations of Tg 38 degrees C cells showed increased excitability as the cells were cooled from 40 degrees C. At 10 degrees C there was a considerable loss of excitability and slope resistance. Cooling Tg 20 degrees C cells from 20 degrees C gave a similar pattern, although over a narrower temperature range. Warming Tg 20 degrees C Tetrahymena above 20 degrees C led to a progressive loss of excitability and the cells were markedly less viable above 35 degrees C. Within physiological limits the regenerative spike magnitude, repolarization time, time to peak and input resistance increased as temperature was lowered, whereas resting potential was diminished. When compared at their growth temperatures and most intermediate temperatures, the value of the various parameters monitored were generally different for the two cultures. The Q10 value for resting potential changes of Tg 20 degrees C cells about 20 degrees C was 1.20. As in T. vorax this was significantly (P less than 0.01) greater than that predicted for a diffusion potential and suggested that T. pyriformis--NT1 may have an electrogenic pump component in its membrane potential.

Animals↗
PubMed1985

Temperature-dependent changes in the swimming behaviour of Tetrahymena pyriformis-NT1 and their interrelationships with electrophysiology and the state of membrane lipids.

The swimming velocity and the amplitude of the helical swimming path of T. pyriformis-NT1 cells grown at 20 degrees C (Tg 20 degrees C) and 38 degrees C (Tg 38 degrees C) were monitored between 0 and 40 degrees C in the presence and absence of electric fields. Within physiological limits the swimming velocity increased and the amplitude decreased as temperature was raised. The temperature profiles of these properties were not linear, and showed discontinuities at different temperatures for the different cultures. The break points in Arrhenius plots of the resting potential, regenerative spike magnitude, repolarization time, swimming velocity and swimming amplitude are tabulated and compared. The initial breakpoints upon cooling were clustered about the breakpoints in fluorescence polarization of D.P.H. in extracted phospholipids, and around the transition temperatures estimated from the literature for the pellicular membrane of these cells. The average of the initial breakpoints on cooling was 22.9 degrees C for Tg 38 degrees C cells and 13.7 degrees C for Tg 20 degrees C cells, a shift of 9.2 degrees C. Unlike Paramecium there is no depolarizing receptor potential in Tetrahymena upon warming. It is suggested that this may be the basis of a behavioural difference between Tetrahymena and Paramecium--namely that in Tetrahymena maximum swimming velocity occurs above growth temperature whereas in Paramecium the two points coincide. Swimming velocity and resting potential were correlated with membrane fluidity within physiological limits, but for other parameters the relationship with fluidity was more complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Driving fatigue.

Explore the source record for details and available documents.

Automobile Driving↗
PubMed1982

An investigation into the validity and reliability of the marking of students' orthodontic practical work.

This study has shown all three examiners to be different; surely a reflection of human nature. One examiner appeared to be strongly influenced by the students' past performance in the course, and the results confirm the findings of Natkin and Guild (1967) that examiners do not always observe the same errors and even when they do, may attach differing importance to the observed deficiency. It was found that an examiner's standard may vary from day to day but, in general, the intra- and inter-examiner correlations were similar to those reported in other studies of undergraduate practical work (Lilley et al., 1968; Silvestri et al., 1979; Goepferd and Kerber, 1980). It may be concluded that: 1. All marking should be done "blind' whenever possible. 2. Marking, once started, should be finished without a break as an examiner's own "pass' standard may vary unduly from one occasion to another. 3. The entire batch of material should be marked by the same examiner, as another could have a significantly different pass standard even though they might agree on the candidates' final order. 4. Because one examiner may subconsciously attach rather more importance to an aspect of the work that another does not notice, there would be a case for two or more examiners carrying out the marking. Their average marks could then be used. In this case, each examiner would, of course, mark the entire batch.

Clinical Competence↗