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Biomedical subjects

A Guppy

Publications and source records attributed to A Guppy.

15 recordsLinked to original sources
PubMed2000

Individual differences, exercise and leisure activity in predicting affective well-being in young adults.

This study focuses on the prevalence of exercise and health-related leisure activities (smoking, drinking), across groups of subjects, defined by personality and gender, in relation to subjective well-being. Results from a cross-sectional survey of 187 participants are reported. Males (n = 80) reported more drinking (p < 0.001) and smoking (p < 0.001) than females, though they also reported higher habitual physical activity levels (p < 0.001). Females (n = 107) reported more frequent use of social support coping (p < 0.01). There was a positive association between extraversion and self-reported habitual physical activity as well as alcohol consumption (even when controlling for gender). Neuroticism was not related to any of the exercise and leisure activity variables. Multiple regression analyses predicted 34% of variance for the depression-enthusiasm and 39% of the variance for the anxiety-contentment measures of affective well-being. Neuroticism (p < 0.001) and avoidance coping (p < 0.05) were the only significant predictors of both anxiety-contentment and depression-enthusiasm. It is concluded that the influence of individual differences such as personality and gender on coping behaviour and well-being is consistent with social learning theory research. Limitations of cross-sectional research designs necessitate caution with inferring causal paths. Recommendations for future research are presented concerning the use and value of repeated measures designs within research into exercise and well-being.

Adaptation, Psychological↗
PubMed1997

Stressors, locus of control, and social support as consequences of affective psychological well-being.

Tests of the influence of affective psychological well-being on stressors, locus of control, and social support in a 1-month follow-up study of 210 male and 34 female British accountants is reported. There was a marginally significant association between the level of psychological symptoms and subsequent reports of intensity of quantitative workload stressors. A significant interaction between psychological symptoms and a measure of depression-enthusiasm was found to predict subsequent locus of control. The results indicate a differential pattern of associations between aspects of affective well-being and subsequent reports of social support. The results also indicate that initially more frequent stressors are associated with subsequently less intense stressors of the same type. The findings highlight the dynamic and reciprocal nature of the occupational stress process.

Accounting↗
PubMed1996

Drivers' biased perceptions of the adverse consequences of drink-driving.

The decision to drink and drive may involve the subjective process of weighing the perceived risks of adverse consequences of the behaviour against perceived utility components. Deterrence theory proposes that an individual will refrain from drink-driving if the perceived chances of experiencing negative outcomes associated with the behaviour are high. Previous research has demonstrated that there may be a mechanism of judgmental bias which influences individuals' perceived probabilities of rarely occurring events. In general driver age and gender have been shown independently to be both indicative and non-indicative for the operation of the bias in terms of subjective perceptions of driver skill, safety and accident involvement. Little evidence has been presented to describe the nature of the bias in the specific domain of drink-driving. Responses from more than 1000 UK drivers were examined to establish whether a system of bias operated for judgments of the likelihood of experiencing several possible adverse consequences of drink-driving across males/females, age groups and offenders/non-offenders. In general drivers were found to perceive themselves as less likely than the average driver to be accident involved while impaired and non-impaired by alcohol. Drivers reporting previous drink-driving behaviour indicated the greatest bias. The age and gender of the driver, independently and in interaction, were not shown to be important in the operation of these perceptual inconsistencies. Findings are discussed for implications of deterrence based drink-driving counter-measures.

Journal Article↗
PubMed1995

The interactionist nature of drinking and driving: a structural model.

A structural model is described that examines the contributions of personal and situational determinants (interactionist theory) for the elicitation of previous self-reported drink-driving offending. Responses of 1011 UK driver's licence holders to 57 questions concerning demographics, driving experience/exposure, deterrence issues, attitudinal factors and situation specific drink-driving behaviour were subjected to a series of multiple regression analyses. Seven variables (five personal and two situational) accounting for 46% of the sample variance were shown to be significantly predictive of undetected offending behaviour. Of these age and safe driving consumption estimates were found to be best described in terms of their direct effects on offending behaviour. The relationships between general alcohol consumption and exposure to secondary level enforcement (breath test) with drink-driving behaviour have both direct and indirect effects. Two attitudinal factors referring to a belief of deterrence if random breath testing were introduced into the UK, and arranging alternative transport on a drinking occasion, as well as exposure to a drink-driving charge, show approximately proportional direct and spurious links with offending. Findings are discussed i n terms of the utility of an interactionist approach for the study of drink-driving behaviour, previous attempts at modelling drink-driving behaviour, and the implications that such results have for counter-measure development.

Adolescent↗
PubMed1995

Speeding in relation to perceptions of risk, utility and driving style by British company car drivers.

Results are presented of a questionnaire survey of speed-related risk-taking performed on 572 British company car drivers. Reported risk-taking was examined in relation to risk and utility perceptions as well as perceived control and driver self-perceptions. The data revealed that over half the sample reported often exceeding the motorway speed limit by at least 10 mph (16 km/h). It was found that drivers who more frequently exceeded the speed limit on motorways were less likely to view speeding as an important risk factor and were much more likely to view being on time for appointments as desirable. They were also likely to view themselves as less aware, less sociable and more confident. The importance of the perceived utility of arriving at appointments on time, in relation to speeding over the legal limit, suggests that some organizational measures to reduce perceived time pressure within company vehicle drivers could be beneficial.

Adult↗
PubMed1995

Behavior and perceptions related to drink-driving among an international sample of company vehicle drivers.

OBJECTIVE: The study examined reported behavior, perceptions and attitudes related to drink-driving among company vehicle drivers located across eight countries. An additional aim of the research was to identify important predictors of drink-driving. METHOD: A cross-sectional mailshot questionnaire survey was undertaken on all drivers of company vehicle identified by the collaborating companies. Responses to items concerning reported drink-driving, perceived consumption limits, perceived risk and reported restraint were examined for a total of 600 male drivers, representing an overall response rate of 55%. RESULTS: Driving after any alcohol consumption was found to be relatively common across most of the sample, while driving when over the legal limit at least once in the previous 12 months was reported by approximately one-third of the drivers. Multiple regression analysis indicated that the strongest predictors of reported drink-driving behavior were associated with perceived limits of personal alcohol consumption and a "moral attachment" to non-drink-driving associated with alcohol consumption restraint. This general prediction model seemed to be relatively consistent across the different national groups. CONCLUSIONS: The results suggest that longer term cognitive components of decision making such as "moral attachment" may form fundamental elements in the decision to drive after excessive drinking. It was suggested that company-based policies and programs may have a useful role in promoting safer driving practices, particularly in relation to driving after drinking.

Accidents, Traffic↗
PubMed1995

Drivers' differential perceptions of legal and safe driving consumption.

UK drink-drive countermeasures have been grounded in deterrence theory and more specifically through per se legislation. Education and information campaigns to stimulate inhibitory behavioural systems have emphasized the legal limit in terms of "driving safeness". This study examined the relationship between subjective perceptions of safe driving and legal driving consumption limits and other factors important in the decision to drive after drinking. Responses from over 900 drivers established that those who perceived safe consumption levels to be greater than that required to break the law indicated reduced moral commitment to present and possible future countermeasures. These drivers also had previous experience of being breath tested (but not charged with a drink-driving offence), reported comparatively lower estimates of their chances of apprehension and accident involvement when over the legal limit, showed higher consumption levels on a driving trip and greater self-reported driving while impaired by alcohol. The implications of the findings for the development and delivery of measures to counter drink-driving are discussed.

Adolescent↗
PubMed1993

Subjective probability of accident and apprehension in relation to self-other bias, age, and reported behavior.

Responses from over 900 male drivers were examined on items measuring the subjective probability of two adverse driving scenarios (accident and apprehension) for a number of speeding and drink-driving-related events. The items were constructed to focus on self versus average referent driver comparisons. Respondents were categorised into "offenders" and "non-offenders" according to their reported behaviour concerning speeding and drink-driving. The data were analysed using repeated measures analysis of variance. The results indicated that both accident and apprehension are seen as less probable when self is the reference compared to the average driver. There was evidence to suggest that this self-favouring bias did vary over presented scenarios. It was suggested that such perceptions may vary in relation to the perceived influence of driver skill within scenarios. Weak age effects were found, but it was concluded that, generally, self-favouring biases were common across all age groups. Concerning the offender/nonoffender classification, the results indicated that speeders and drink-drivers generally perceived the probability of apprehension and accident as being lower than did the nonoffender groups. There was no evidence to suggest that self-average driver biases were associated with offender/nonoffender grouping.

Accidents, Traffic↗
PubMed1989

Frequency sensitivity and directional hearing in the gleaning bat, Plecotus auritus (Linnaeus 1758).

1. The neural audiogram of the common long-eared bat, Plecotus auritus was recorded from the inferior colliculus (IC). The most sensitive best frequency (BF) thresholds for single neurones are below 0 dB SPL between 7-20 kHz, reaching a best value of -20 dB SPL between 12-20 kHz. The lower and upper limits of hearing occur at 3 kHz and 63 kHz, respectively, based on BF thresholds at 80 dB SPL. BF threshold sensitivities are about 10 dB SPL between 25-50 kHz, corresponding to the energy band of the sonar pulse (26-78 kHz). The tonotopic organization of the central nucleus of the IC (ICC) reveals that neurones with BFs below 20 kHz are disproportionately represented, occupying about 30% of ICC volume, occurring in the more rostral and lateral regions of the nucleus. 2. The acoustical gain of the external ear reaches a peak of about 20 dB between 8-20 kHz. The gain of the pinna increases rapidly above 4 kHz, to a peak of about 15 dB at 7-12 kHz. The pinna gain curve is similar to that of a simple, finite length acoustic horn; expected horn gain is calculated from the average dimensions of the pinna. 3. The directional properties of the external ear are based on sound diffraction by the pinna mouth, which, to a first approximation, is equivalent to an elliptical opening due to the elongated shape of the pinna. The spatial receptive field properties for IC neurones are related to the directional properties of the pinna. The position of the acoustic axis of the pinna and the best position (BP) of spatial receptive fields are both about 25 degrees from the midline between 8-30 kHz but approach the midline to 8 degrees at 45 kHz. In elevation, the acoustic axis and the BP of receptive fields move upwards by 20 degrees between 9-25 kHz, remaining stationary for frequencies up to 60 kHz. 4. The extremely high auditory sensitivity shown by the audiogram and the directionality of hearing are discussed in terms of the adaptation of the auditory system to low frequencies and the role of a large pinna in P. auritus. The functional significance of low frequency hearing in P. auritus is discussed in relation to hunting for prey by listening and is compared to other gleaning species.

Acoustic Stimulation↗
PubMed1988

Directional hearing in the barn owl (Tyto alba).

The acoustical properties of the external ear of the barn owl (Tyto alba) were studied by measuring sound pressure in the ear canal and outer ear cavity. Under normal conditions, pressure amplification by the external ear reaches about 20 dB between 3-9 kHz but decreases sharply above 10 kHz. The acoustic gain curve of the outer ear cavity alone is close to that of a finite-length exponential horn between 1.2-13 kHz with maximum gain reaching 20 dB between 5-9 kHz. Pressure gain by the facial ruff produces a maximum of 12 dB between 5-8 kHz and decreases rapidly above 9 kHz. The directional sensitivity of the external ear was obtained from pressure measurements in the ear canal. Directivity of the major lobe is explained, to a first approximation, by the sound diffraction properties of a circular aperture. Aperture size is based on the average radius (30 mm) of the open face of the ruff. Above 5 kHz, the external ear becomes highly directional and there is a 26 degree disparity in elevation between the acoustic axis of the left and right ear. In azimuth, directivity patterns are relocated closer to the midline as frequency increases and the acoustic axis moves at a rate of 20 degree/octave between 2-13 kHz. Movement of the axis can be explained, to a first approximation, by the acoustical diffraction properties of an obliquely truncated horn, due to the asymmetrical shape of the outer ear cavity. The directional sensitivity of the barn owl ear was studied by recording cochlear microphonic (CM) potentials from the round window membrane. Between 3-9 kHz, CM directivity patterns are clearly different to the directivity patterns of the external ear; CM directionality is abruptly lost above 10 kHz. Above 5 kHz, CM directivity patterns are characterized by an elongated major lobe containing the CM axis, forming a tilted band of high amplitude but low directionality (CM axial plane), closely bordered by minima or nulls. The highest directionality is found in the CM directional plane, approximately perpendicular to the CM axial plane. The left and right ear axial planes are symmetrical about the interaural midline (tilted 12 degrees to the right of the midline of the head) and inclined by an average of 60 degrees to the left and right respectively. In azimuth, the CM axis moves towards the midline at a rate of 37 degrees/octave as frequency increases from 2-9 kHz, crossing into contralateral space near 7 kHz.(ABSTRACT TRUNCATED AT 400 WORDS)

Acoustic Stimulation↗
PubMed1988

Acoustical and neural aspects of hearing in the Australian gleaning bats, Macroderma gigas and Nyctophilus gouldi.

1. The maximum acoustic gain of the external ear in Macroderma gigas was found to be 25-30 dB between 5-8 kHz and in Nyctophilus gouldi it reached 15-23 dB between 7-22 kHz. Pinna gain reached a peak of 16 dB near 4.5-6 kHz in M. gigas and 12-17 dB between 7-12 kHz in N. gouldi, with average gain of 6-10 dB up to 100 kHz. Pinna gain curves resemble that of a finite conical horn, including resonance. 2. The directional properties of the external ear in both species result from sound diffraction at the pinna face, as it approximates a circular aperture. The frequency dependent movement of the acoustic axis in azimuth and elevation is attributed to the asymmetrical structure of the pinnae. 3. Evoked potentials and neuronal responses were studied in the inferior colliculus. In M. gigas, the neural audiogram has sensitivity peaks at 10-20 kHz and 35-43 kHz, with extremely low thresholds (-18 dB SPL) in the low frequency region. In N. gouldi, the neural audiogram has sensitivity peaks at 8-14 kHz (lowest threshold 5 dB SPL) and 22-45 kHz. Removal of the contralateral pinna causes a frequency dependent loss in neural threshold sensitivity of up to 10-15 dB in both species. 4. The high frequency peak in the audiogram coincides with the sonar energy band in both species, whereas the low frequency region is used for social communication. Highly sensitive low frequency hearing is discussed in relation to hunting in bats by passive listening.

Acoustic Stimulation↗
PubMed1988

The effects of alcohol on speed perception in a closed-course driving situation.

The present study examined the effect of alcohol on the perception of speed in a closed-course driving situation. Male subjects (N = 24) classified with respect to previous drinking experience were used in the experiment. Each subject was tested on a speed estimation task at blood alcohol levels (BALs) of 0 and 100 mg/dl. Subjects were required to decelerate from a constant speed of 30 mph to a target speed of 20 mph under two conditions: using their speedometer and being deprived of its use. Of interest were the subjective judgments made under the latter conditions. Results show that there was no significant effect of alcohol on the perception of speed. The expected interaction between previous drinking experience and alcohol dose was found to be nonsignificant. Overall, a significant difference in performance between the two speedometer conditions indicated that subjects overestimated the target speed when they were not given access to their speedometer. Possible explanations and implications of these findings are discussed and future directions for research are suggested.

Adult↗
PubMedDate not supplied

Electroreception and electrolocation in platypus.

Electroreceptors with sensitivity in the microvolt range, which mainly function to detect live prey, are well known in phylogenetically old fishes and some amphibians. In African mormyriform and South American gymnotiform fishes this sense has evolved to an active system using an electric organ as a source for impedance measurement of the environment and for communication. Electroreception in higher vertebrates has not previously been reported. Here we establish that the platypus, the Australian nocturnal diving monotreme, can locate and avoid objects on the basis of d.c. fields. High-frequency sensitivity to a.c. could allow the detection of muscle activity of animals, such as crustaceans, which are preyed on by the platypus. Recordings of cortical evoked potentials showed that the bill of the platypus, previously considered to be exclusively mechanoreceptive, is also an electroreceptive organ with behavioural and electrophysiological sensitivity of approximately 50 microV cm-1. Several lines of evidence suggest that electroreception has evolved independently in this monotreme.

Animals↗