Management and control of agri-chemical pesticides: any progress?

Issues related to agri-chemical pesticides usage and poisonings in South Africa have been well documented. Under-reporting of information required to determine the size of the problem complicates current surveillance and prevention programmes. The study aimed to determine: the procedure for reporting and follow-up of cases of agricultural pesticide poisonings; which factors contributed to the poisoning cases; and whether a biological monitoring programme was in place at the time of 110 reported cases of agri-chemical poisonings on farms in the Boland Health District between 1997 and 2000. A retrospective descriptive survey design involving a record review was applied. The study found that the cases were poorly reported. The follow up system at the local level between local government officials and the farmers was not efficient for the prevention of agrichemical poisonings. The contributory factors were insufficient information and training; the incorrect use of personal protective equipment; the lack of safety of the agri-chemical store; and the absence of a monitoring system on the majority of farms. This study demonstrated that the notification of agricultural chemical poisoning was applied in a fragmentary manner between the different governmental levels and departments

An experimental evaluation of instantaneous self-assessment as a measure of workload.

Instantaneous self-assessment (ISA) is a technique that has been developed as a measure of workload to provide immediate subjective ratings of work demands during the performance of primary work tasks such as air traffic control. This paper reports a study that compared the results of ISA with those gathered from other established workload evaluation techniques; subjective ratings collected at the end of the task, mean heart rate and heart rate variability, and error in the primary task of tracking. ISA ratings were found to be correlated significantly with the post-task ratings of workload, heart rate variability, and task performance. Generally each of the techniques was sensitive to variations in task difficulty. However, performance on the primary tracking task was found to be poorer during periods when ISA responses were required, regardless of whether they were spoken or manual responses. This finding suggests that the usefulness of the technique is limited in comparison to less intrusive measures of workload.

Level of operator control and changes in heart rate variability during simulated flight maintenance.

The demands of dynamic monitoring and fault diagnosis for flight engineer trainees were examined in relation to changes in heart rate (HR) and two spectral analysis measures (midfrequency: 0.07-0.14 Hz; high frequency: 0.15-0.40 Hz) of heart rate variability (HRV). Eleven trainee flight engineers were studied, as part of their training and assessment, over three 3-h sessions in a cockpit simulator. During each session, faults and incidents programmed into the system had to be detected, diagnosed, and corrected. Electrocardiograms were taken, and each session was recorded on videotape. Work phases were classified from video analysis of flight maintenance activities, using Rasmussen's cognitive control taxonomy, into monitoring, routine (rule-based), and problem-solving (knowledge-based) phases. HR and HRV were found to be sensitive to different phases of the work environment. HRV was suppressed during the mentally demanding problem-solving mode of the level flight phase, but only for the midfrequency component. Elevated heart rate, in contrast, was associated with the more generally stressful takeoff and landing phases. The findings support both the use of HRV as a physiological index of mental effort and its value in operational contexts, and the value of ecologically derived methods of evaluating differences in work demands in complex systems.

Assessing the impact of computer workload on operator stress: the role of system controllability.

This paper considers the impact of working with computer-based systems in terms of mental workload and the well-being of operators. In particular, the paper focuses on issues of controllability in human-computer systems as they relate to operator stress. Through the adoption of a state control model of stress regulation, it becomes apparent that while general usability criteria are necessary for the design of controllable systems, they may not be sufficient to guarantee controllability. The implications for research and system design are discussed, with reference to the assessment of operator workload, controllability and stress. A methodology for assessing computer stress is described, based on the analysis of stressful computer-related episodes and their accompanying affective and cognitive states. This technique allows the relationship between workload and controllability to be studied in particular computer work environments, in relation to individual work goals and coping strategies.

The use of a hand-held computer to record clinical trial data in general practice: a pilot study.

A system has been developed to collect and process clinical trial data in general practice using a hand-held computer in the patient's presence. It was based on a Psion Organiser II (model XP) computer using software produced for the trial. The major advantages are: (a) avoidance of protocol violations and other incorrect data entries; and (b) saving of time for investigators and company personnel. The present coding of symptoms was found to be the only major drawback, but this problem could be remedied for future studies.

Retrospective post-marketing surveillance of Transiderm-Nitro 5 in general practice in the United Kingdom.

A retrospective post-marketing surveillance of Transiderm-Nitro 5 was undertaken in 1803 general practice patients with various degrees of severity of angina. Over half the patients were assessed more than 3 months after starting treatment. At the time of assessment two-thirds of the patients were continuing with their Transiderm-Nitro therapy. Only a small proportion (3.8%) of the total patient population were withdrawn after 3 months' usage. This suggests the continuing benefit of longer term Transiderm-Nitro therapy. Subjective assessment of a reduction in the number of anginal attacks and an improvement in exercise capacity occurred, respectively, in 76.2% and 62.6% of the patients. Although 16% of patients experienced problems specifically related to patch use, only 6.4% withdrew for these reasons. The incidence of headache decreased with time of usage of Transiderm-Nitro to give an over-all withdrawal of 7%. The death rate observed during the surveillance lies between that for the United Kingdom population as a whole and that for a population with angina pectoris. This surveillance shows that both patients and doctors perceived clinical benefit from Transiderm-Nitro when used in the treatment of angina.

Irish general practice study of acetylcysteine (Fabrol) in chronic bronchitis.

The results of this general practice study in 248 patients suggest that acetylcysteine (Fabrol) administered orally for 2 months to patients with chronic bronchitis effectively changes the viscosity and character of sputum with resultant ease of expectoration and cough severity. There was a notable improvement in associated abnormal physical signs such as the presence of rhonchi, crepitations and symptoms including dyspnoea at rest. Tolerability was good, with 77% of patients experiencing no side-effects.

Post-marketing surveillance of the Transiderm-Nitro patch in general practice.

Post-Marketing Surveillance (PMS) of Transiderm-Nitro, a new transdermal form of nitroglycerin, was undertaken during the 6 months following its introduction to general practitioners in the United Kingdom. Two thousand four hundred and seventy-five record forms were received. Excluding the fourteen patients who died during the surveillance, treatment in the remaining 2461 was judged as effective in 80.6% of patients and was well tolerated, with 70.5% having no unwanted effects. The incidences of withdrawal from Transiderm-Nitro in all patients analyzed were 5.7% due to headaches, 3.6% due to other unwanted effects and only 3.1% due to the treatment being judged as ineffective. This PMS confirms that Transiderm-Nitro is an effective, well tolerated addition to the therapy of angina pectoris.

Acetylcysteine (Fabrol) in chronic bronchitis--a study in general practice.

The results of this general practice study suggest that acetylcysteine (Fabrol) administered orally for 2 months to patients with chronic bronchitis effectively changes the viscosity and character of sputum with resultant ease of expectoration and cough severity. There was a notable improvement in associated abnormal physical signs such as the presence of rhonchi, crepitations and symptoms including dyspnoea at rest. Tolerability was good, with 81% of patients experiencing no side-effects.