The influence of geochemistry on health risks to animals and humans in geographically localised livestock production systems

(South African J of Animal Science, 2000, 30, Supplement 1: 82-84

School self-evaluation for school improvement: Examining the measuring properties of the LEAD surveys

Research evidence suggests school self-evaluation with the participation of school stakeholders could improve teaching and learning. Identification and use of appropriate self-evaluation frameworks, however, is not an easy task for schools. Such a framework, the LEAD School Effectiveness Surveys, has been developed by Independent Schools Victoria in Australia. The LEAD suite of school stakeholder surveys enables schools to evaluate their overall effectiveness in several domains and make informed decisions for school improvement. This article evaluates the reliability as well as the face, content and construct validity of the LEAD surveys and discusses the ways in which school self-evaluation results could contribute to school improvement. Data were gathered from a total of 119,749 students, teaching staff, general and parents taking the LEAD Surveys in 112 independent (non-government) schools and followed a five-year longitudinal design from 2009 to 2013. The results support the reliability as well as the face, content and construct validity of the LEAD surveys. The importance of evaluating the measuring properties of instruments used for school self-evaluation is discussed and suggestions for school self-evaluation are provided. Independent Schools Victoria (Australia

The effect of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under isoflurane anaesthesia in an ovine model

Publisher's copy made available with the permission of the publisher © Australian Society of AnaesthetistsThe effects of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under steady-state isoflurane anaesthesia were compared with the awake state. Six studies each were conducted in two cohorts of adult ewes: awake sheep and those anaesthetized with 2% isoflurane anaesthesia. In random order, each animal received ramped infusions of adrenaline, noradrenaline (0-40 µg/min) and dopamine (0-40 µg/kg/min). Cerebral blood flow was measured continuously from changes in Doppler velocities in the sagittal sinus. Autoregulation was determined by linear regression analysis between cerebral blood flow and mean arterial pressure. Isoflurane did not significantly alter cerebral blood flow relative to pre-anaesthesia values (P>0.05). All three catecholamines significantly and equivalently increased MAP from baseline in a dose dependent manner in both the awake and isoflurane cohorts. Although adrenaline significantly increased cerebral blood flow from baseline in the awake cohort (P0.05). Over a specific dose range, systemic hypertension induced by adrenaline, noradrenaline and dopamine did not significantly increase cerebral blood flow under 2% isoflurane anaesthesia. The concomitant administration of isoflurane and the catecholamines was not associated with altered autoregulatory function compared to the awake state.http://www.aaic.net.au/Article.asp?D=200236

Cerebrovascular carbon dioxide reactivity in sheep: Effect of propofol or isoflurane anaesthesia

Publisher's copy made available with the permission of the publisher © Australian Society of AnaesthetistsPropofol and isoflurane are commonly used in neuroanaesthesia. Some published data suggest that the use of these agents is associated with impaired cerebral blood flow/carbon dioxide (CO₂) reactivity. Cerebrovascular CO₂ reactivity was therefore measured in three cohorts of adult merino sheep: awake (n=6), anaesthetized with steady-state propofol (15 mg/min; n=6) and anaesthetized with 2% isoflurane (n=6). Changes in cerebral blood flow were measured continuously from changes in velocities of blood in the sagittal sinus via a Doppler probe. Alterations in the partial pressure of carbon dioxide in arterial blood (PaCO₂) over the range 18-63 mmHg were achieved by altering either the inspired CO₂ concentration or the rate of mechanical ventilation. Cerebral blood flow/CO₂ relationships were determined by linear regression analysis, with changes in cerebral blood flow expressed as a percentage of the value for a PaCO₂ of 35 mmHg. Propofol decreased cerebral blood flow by 55% relative to pre-anaesthesia values (P=0.0001), while isoflurane did not significantly alter cerebral blood flow (88.45% of baseline, P=0.39). Significant linear relationships between cerebral blood flow and CO₂ tension were determined in all individual studies (r2 ranged from 0.72 to 0.99). The slopes of the lines were highly variable between individuals for the awake cohort (mean 4.73, 1.42-7.12, 95% CI). The slopes for the propofol (mean 2.67, 2.06-3.28, 95% CI) and isoflurane (mean 2.82, 2.19-3.45, 95% CI) cohorts were more predictable. However, there was no significant difference between these anaesthetic agents with respect to the CO₂ reactivity of cerebral blood flow.J. A. Myburgh, R. N. Upton, G. L. Ludbrook, A. Martinez, C. Granthttp://www.aaic.net.au/Article.asp?D=200137

Access to health care in South Africa - the influence of race and class

Objectives. The first democratic government elected in South Africa in 1994 inherited huge inequities in health status and health provision across all section of the population. This study set out to assess the impact of the new government's commitment to address these inequities and implement policies to improve population health in general and address inequities in health care in particular. Design. A 1998 household survey assessed many aspects of health delivery, including their own perceived and actual access to health care among different segment of South Africa society. Results. Race was the main predictor of perceived changes in access to health care, with black, coloured and Indian respondents significatly more likely to feel that access had improved since 1994, compared with white respondents. Socio-economic status (SES) was the main predictor of actual access to health care, with low and middle SES classes significantly less likely to access care when ill. Conclusions. One-third of respondents perceived health care access to have improved between 1994 and 1998, and this response was partially determined along racial lines. About one-quarter reported an inability to access health care when they required it, and this response was partially determined along socio-economic lines. This set of contrasting responses suggests that at a political level perceptions are largely influenced by race, but at the operational level actual access is influenced by SES

Food items consumed by students attending schools in different socio-economic areas in Cape Town, South Africa

Objective: We investigated the food consumption patterns of adolescent students at schools. Our findings are intended to reveal the overall nutritional quality of foods eaten by students at school, including foods brought to school and foods purchased at school. Methods: A questionnaire was completed by 476 students, mostly from grades 7 and 10, from 14 schools in Cape Town, South Africa. The schools were representative of the various ethnic groups and socioeconomic strata of the population. The questionnaire requested information on eating habits at school, foods brought to school and food purchases, and breakfast consumption before school. We also tested whether students knew which foods are healthy and which are less healthy choices. Results: The students were mostly 12 to 16 y of age (mean age 14.5 y). The large majority had breakfast before school (77.8%) and ate at school (79.7%). Food was brought to school by 41% to 56%, whereas 69.3% purchased food at school, mainly at the school store (tuck shop). Predefined “unhealthy” foods brought to school outnumbered “healthy” ones by 2 to 1. Among students who purchased food at school, 70.0% purchased no healthy items, whereas 73.2% purchased two or more unhealthy items. With six foods 84% of students correctly stated whether they were healthy or unhealthy; however, with cola drinks, samoosas (deep-fried pastry with spicy filling), and pies, only 47% to 61% knew that these were less healthy choices. Students’ scores on this question were unrelated to whether they purchased healthy or unhealthy foods. Students who attended schools of high socioeconomic status were twice as likely to bring food to school (64.7% versus 31.0%, P < 0.001), scored higher marks on the quiz of healthy versus unhealthy foods (P < 0.01), but were no more likely to purchase healthy food. Conclusions: The large majority of food eaten by adolescent students in Cape Town is classified as being unhealthy choices. This applies to foods brought to school and food purchases. Consideration needs to be given to policy measures to improve this situation and to improve education of students and their parents