Biomedical subjects

P K Arnold

Publications and source records attributed to P K Arnold.

9 recordsLinked to original sources

PubMed1997

Hours of work, and perceptions of fatigue among truck drivers.

Drivers and companies operating in the heavy road transport industry were surveyed about drivers' hours of work and perceptions of the causes and magnitude of fatigue as an industry problem. These drivers were operating in a state which, at the time of the survey, did not restrict driving hours for heavy haulage drivers. On the day of the interview, estimates based on retrospective and prospective reports, suggest that in a 24 hour period about 38% of drivers exceed 14 hours of driving, and 51% exceed 14 hours of driving plus other non-driving work. About 12% of drivers reported less than 4 hours of sleep on one or more working days in the week preceding the interview. These drivers are likely to be operating their vehicles while having a significant sleep debt. About 20% of drivers reported less than 6 hours sleep before starting their current journey, but nearly 40% of dangerous events that occurred on the journey were reported by these drivers (p < 0.05). Many drivers and company representatives reported fatigue to be a problem for other drivers, but considered themselves or their companies' drivers to be relatively unaffected by fatigue. There were differences between drivers' and companies' perceptions about causes of fatigue, and strategies that should be used to manage it. The results obtained from these drivers in an unregulated state were compared with earlier findings from drivers in states where driving hours restrictions are in place.

Accidents, Occupational↗

PubMed1994

Indicators of fatigue in truck drivers.

This study examined physiological and psychological changes in one solo truck driver and both drivers in a two-up truck crew during several 5-6 day round-trips to the north west of Western Australia. Endocrine catecholamine levels, cardiac sinus arrhythmia and serial reaction performance all showed progressive changes over the journey. The solo driver showed greater changes on most measures than the two-up crew and compared with control measures obtained from research assistants accompanying the drivers. The results suggest that solo drivers may experience more fatigue, impaired capacity for controlled mental effort and slowed reactions than a two-up crew.

Journal Article↗

PubMed1992

Travel exposure and choice of comparison crashes for examining motorcycle conspicuity by analysis of crash data.

Much research has been conducted examining the problem of motorcycle road crashes. Most of this research has concluded that motorcyclists have a conspicuity problem, particularly during the day. This type of research has often involved comparing multi-vehicle motorcycle crashes with single vehicle motorcycle crashes occurring during the day and night. The aim of this paper is to point out that comparison of single and multiple vehicle motorcycle crashes juxtaposes subsets of crashes with clearly different causes (car drivers' possible failure to detect a motorcyclist against motorcyclists' loss of vehicle control). Comparing groups of crashes for which conspicuity can be posited as a common cause (car drivers' possible failure to detect a motorcyclist or car) may be a more enlightening comparison. The issue of exposure is also examined in this paper.

Accidents, Traffic↗

PubMed1991

Chlorpromazine and the lateralisation of the perception of emotion.

In a double-blind design, sixteen volunteer students were administered 50 mg of chlorpromazine or a placebo in tablet form on separate occasions, two hours prior to testing. The test was a lexical decision paradigm involving unilateral presentation of pairs of neutral, positive and negative emotional words and nonwords to the left or right visual fields. Reaction time to identify words and nonwords was recorded. Neutral stimuli were processed faster in the left hemisphere, while negative stimuli were processed faster in the right hemisphere. Chlorpromazine improved speed of response for neutral stimuli presented to the right hemisphere and for affective stimuli presented to the left hemisphere. Thus chlorpromazine seems to benefit right hemisphere processing of nonaffective stimuli and benefit left hemisphere processing of affective stimuli. Chlorpromazine appeared to have a different impact on neutral and affective words, and on the right and the left hemispheres. The general effect of chlorpromazine was to reduce lateralisation. It was suggested that this occurred because chlorpromazine blocked dopamine and possibly other neurotransmitters.

Adult↗

PubMed1990

Training for an agricultural discrimination task.

Skeleton weed, centaurea juncea, is a declared weed in Western Australia because it competes with grain crops for nutrients and moisture. When it is found during harvesting, mechanised teams search and eradicate it. In an earlier report of field trials (Hartley et al, 1989) it was reported that search teams' detection rate was poor and since search teams had usually never seen skeleton weeds, visual discrimination learning was to be expected and observed during searches. The present study investigated the nature of this discrimination learning in a laboratory by developing a training programme of colour photographic slides of weeds in stubble. Subjects receiving specific training with feedback on their performance compared with those receiving pseudo-training showed a significant improvement in detections. Subsequently the benefit of the programme was validated in a field trial.

Journal Article↗

PubMed1990

Listening, priming and emotion under a neuroleptic drug.

The authors previously found that emotional arousal increased the asymmetry of facial and other lateralised expressive behaviours. Chlorpromazine equalized the symmetry of behaviour by reducing emotional arousal rather than by blocking all behaviour. These results raise the question of whether the perception of emotion is also lateralised and similarly influenced by chlorpromazine. Sixteen student volunteers were administered placebo and 50 mg of chlorpromazine in tablet form on separate occasions two hours before carrying out two tests of lateralised perception. Dichotic recognition of positive and neutral but not negative emotional words revealed a right ear advantage. No drug effect was observed. The speed of recognition of words and nonwords was also examined following emotionally toned priming words lateralised to the visual hemifields. This task showed some parallel findings to the dichotic test but some lateralised effect of the drug was observed.

Adult↗

PubMed1989

Vigilance, visual search and attention in an agricultural task.

In a fragile agricultural environment, such as Western Australia (WA), introduced exotic plant species present a serious environmental and economic threat. Skeleton weed, centaurea juncea, a Mediterranean daisy, was accidentally introduced into WA in 1963. It competes with cash crops such as wheat. When observed in the fields, farms are quarantined and mechanised teams search for the infestations in order to destroy them. Since the search process requires attention, visual search and vigilance, the present investigators conducted a number of controlled field trials to identify the importance of these factors in detection of the weed. The paper describes the basic hit rate, vigilance decrement, effect of search party size, effect of target size, and some data on the effect of solar illumination of the target. Several recommendations have been made and incorporated in the search programme and some laboratory studies undertaken to answer questions arising.

Journal Article↗

PubMed1989

Lateralization of emotional expression under a neuroleptic drug.

Sixteen student volunteers were administered placebo and 50 mg of chlorpromazine (CPZ) in tablet form, on separate occasions, two hours before testing. Whilst volunteers related pleasant and unpleasant personal life events, the frequency and intensity of expressions on the left and right sides of the face were rated by independent observers. Subsequently the valence of the narration was also rated. Similar to a previous study facial expressions during negative emotions were expressed more often and intensely in the left face but positive emotions were bilaterally represented. CPZ neutralised the emotion on both sides of the face, irrespective of whether it was positive or negative. However, because negative emotions were almost completely lateralised to the left face the drug's effect on this emotion was most pronounced on this side. Independent ratings of the narration of the life events showed CPZ made them more pleasant. It is suggested that emotional arousal increases the asymmetry of behaviours when these are unilaterally represented or controlled. CPZ may equalize the symmetry of behaviour by reducing emotional arousal rather than by blocking all behaviour.

Adolescent↗

PubMedDate not supplied

Clinical skills and knowledge used by veterinary graduates during their first year in small animal practice.

OBJECTIVE: To determine the clinical skills and areas of knowledge used by veterinarians in small animal practice during their first year after graduation and the degree of assistance and supervision they received while developing these skills. DESIGN: A postal survey was sent in December 1999 to 59 veterinarians who completed their training at Murdoch University in December 1998. PROCEDURE: The first part of the survey asked for information on veterinary work patterns since leaving university. The second part consisted of a list of diagnostic and therapeutic skills of varying complexity and the graduates were asked to indicate whether they had used these skills in practice and whether they had been assisted or supervised while doing them. The respondents were also asked if they had had the opportunity to practise these skills as undergraduates at university or during extramural experience. In the third part the areas of knowledge used in practice were assessed by analysis of a series of consecutive cases. RESULTS: Forty replies were received but since three graduates had done no small animal work the analysis of the skills section is based on 37 responses. Thirty graduates supplied information on 994 canine cases and 308 feline cases. The distribution of the mean work time was dogs and cats 69%, horses 13%, farm animals 11%, birds 3% and others 4%. Skills used by over 90% of graduates included general anaesthesia, examination of the tympanic membrane, taking and interpreting an abdominal radiograph, catheterising a male cat, fine needle aspiration of a mass, neutering dogs and cats, tooth scaling and extraction and treating an aural haematoma. The survey also identified the opportunities for undergraduates to practise some of these skills during extramural experence and the extent of assistance given to new graduates during their first year in practice. The areas of knowledge used in over 10% of the cases included vaccination, anaesthesia/sedation, skin/coat problems, general advice on pet health, neutering and musculoskeletal diseases. CONCLUSION: Veterinarians, in their first year after graduation, use a wide range of complex diagnostic and therapeutic skills. Although many of these skills are acquired during the undergraduate training, a significant contribution is made by extramural practical work undertaken during the clinical years of the undergraduate course and in the first year following graduation. Practising veterinarians play an important role in providing opportunities and supervision for clinical training.

Animals↗