Quantitative microbial risk assessment modelling for the use of reclaimed water in irrigated horticulture

Reuse of treated sewage effluent for the irrigation of horticultural crops is being propounded and practiced as a means of alleviating pressure on freshwater resources. Concerns have been raised. however, as to the risk to human health, primarily disease, associated with this practice. Quantitative Microbial Risk Assessment (QMRA) is a useful tool for estimating this risk. We describe how QMRA works and the current state of knowledge of the components of QMRA models for the horticultural reuse scenario.

Quantitative evaluation in health promotion : What's the difference?

This is the third in a series of articles on quantitative evaluation in health promotion written by Damien Jolley for the Health Promotion Journal of Australia. The first of these articles, published in the December 2000 issue, discussed the ideas behind sample surveys and how they can be used to improve evaluation of health promotion initiatives.1 The second, in the April 2001 issue, discussed confidence intervals in more detail and presented some strategies for computing confidence intervals for population percentages, both manually and using appropriate computer software. 2

Fattening foods - perceptions and misconceptions: a qualitative and quantitative exploration

Describes adults' perceptions and beliefs about foods that are considered "fattening". Use of qualitative and quantitative methods to determine the prevalence of the perceptions among adults; Range of factors that are considered when judging foods as "fattening"; Limitations in the public's understandings of "fattening foods" which are inconsistent with dietary recommendations.

Children's perceptions of their home and neighborhood environments, and their association with objectively measured physical activity: A qualitative and quantitative study

Environmental factors may have an important influence on children’s physical activity, yet children’s perspectives of their home and neighborhood environments have not been widely assessed. The aim of this study was to investigate children’s perceptions of their environments, and to examine associations between these perceptions and objectively measured physical activity. The sample consisted of 147, 10-year-old Australian children, who drew maps of their home and neighborhood environments. A subsample of children photographed places and things in these environments that were important to them. The maps were analyzed for themes, and for the frequency with which particular objects and locations appeared. Physical activity was objectively measured using accelerometers. Six themes emerged from the qualitative analysis of the maps and photographs: the family home; opportunities for physical activity and sedentary pursuits; food items and locations; green space and outside areas; the school and opportunities for social interaction. Of the 11 variables established from these themes, one home and two neighborhood factors were associated with children’s physical activity. These findings contribute to a broader understanding of children’s perceptions of their environment, and highlight the potential importance of the home and neighborhood environments for promoting physical activity behavior.

Clinical research 5: quantitative data collection and analysis

This six-part research series is aimed at clinicians who wish to develop research skills, or who have a particular clinical problem that they think could be addressed through research. The series aims to provide insight into the decisions that researchers make in the course of their work, and to also provide a foundation for decisions that nurses may make in applying the findings of a study to practice in their own Unit or Department. The series emphasises the practical issues encountered when undertaking research in critical care settings; readers are encouraged to source research methodology textbooks for more detailed guidance on specific aspects of the research process.

A couple of points:

1. It is artificial to describe research as qualitative or quantitative. Studies often include both dimensions. However, for the purposes of this paper/series, this distinction is drawn for clarity of writing.

2. It is common practice for quantitative studies to refer to study ‘subjects’ and qualitative studies to refer to study ‘participants’. For ease of reading, the latter term will be used throughout this series.

Beliefs about genetically modified foods : a qualitative and quantitative exploration

This study is aimed to examine consumers' beliefs about genetically modified foods. Ten focus group interviews of community members and a random questionnaire-based mail survey of 500 Australian (Victorian) adults were conducted (58% response). Participants were generally negative about genetically modified foods, with concerns being raised about them being unnatural, difficult to identify, and having unknown long-term health and environmental effects. Many participants were unaware of or disagreed with the benefits of genetically modified foods that are promoted by its advocates and there were some misconceptions present. These findings provide information for both advocates and opponents of genetically modified foods and a basis for future larger-scale research.

Quantitative microbial risk assessment models for consumption of raw vegetables irrigated with reclaimed water

Quantitative microbial risk assessment models for estimating the annual risk of enteric virus infection associated with consuming raw vegetables that have been overhead irrigated with nondisinfected secondary treated reclaimed water were constructed. We ran models for several different scenarios of crop type, viral concentration in effluent, and time since last irrigation event. The mean annual risk of infection was always less for cucumber than for broccoli, cabbage, or lettuce. Across the various crops, effluent qualities, and viral decay rates considered, the annual risk of infection ranged from 10–3 to 10–1 when reclaimed-water irrigation ceased 1 day before harvest and from 10–9 to 10–3 when it ceased 2 weeks before harvest. Two previously published decay coefficients were used to describe the die-off of viruses in the environment. For all combinations of crop type and effluent quality, application of the more aggressive decay coefficient led to annual risks of infection that satisfied the commonly propounded benchmark of ≤10–4, i.e., one infection or less per 10,000 people per year, providing that 14 days had elapsed since irrigation with reclaimed water. Conversely, this benchmark was not attained for any combination of crop and water quality when this withholding period was 1 day. The lower decay rate conferred markedly less protection, with broccoli and cucumber being the only crops satisfying the 10–4 standard for all water qualities after a 14-day withholding period. Sensitivity analyses on the models revealed that in nearly all cases, variation in the amount of produce consumed had the most significant effect on the total uncertainty surrounding the estimate of annual infection risk. The models presented cover what would generally be considered to be worst-case scenarios: overhead irrigation and consumption of vegetables raw. Practices such as subsurface, furrow, or drip irrigation and postharvest washing/disinfection and food preparation could substantially lower risks and need to be considered in future models, particularly for developed nations where these extra risk reduction measures are more common.

MRI-negative PET-positive temporal lobe epilepsy (TLE) and mesial TLE differ with quantitative MRI and PET: a case control study

Background: 'MRI negative PET positive temporal lobe epilepsy' represents a substantial minority of temporal lobe epilepsy (TLE). Clinicopathological and qualitative imaging differences from mesial temporal lobe epilepsy are reported. We aimed to compare TLE with hippocampal sclerosis (HS+ve) and non lesional TLE without HS (HS-ve) on MRI, with respect to quantitative FDG-PET and MRI measures.

Methods: 30 consecutive HS-ve patients with well-lateralised EEG were compared with 30 age- and sex-matched HS+ve patients with well-lateralised EEG. Cerebral, cortical lobar and hippocampal volumetric and co-registered FDG-PET metabolic analyses were performed.

Results: There was no difference in whole brain, cerebral or cerebral cortical volumes. Both groups showed marginally smaller cerebral volumes ipsilateral to epileptogenic side (HS-ve 0.99, p = 0.02, HS+ve 0.98, p < 0.001). In HS+ve, the ratio of epileptogenic cerebrum to whole brain volume was less (p = 0.02); the ratio of epileptogenic cerebral cortex to whole brain in the HS+ve group approached significance (p = 0.06). Relative volume deficits were seen in HS+ve in insular and temporal lobes. Both groups showed marked ipsilateral hypometabolism (p < 0.001), most marked in temporal cortex. Mean hypointensity was more marked in epileptogenic-to-contralateral hippocampus in HS+ve (ratio: 0.86 vs 0.95, p < 0.001). The mean FDG-PET ratio of ipsilateral to contralateral cerebral cortex however was low in both groups (ratio: HS-ve 0.97, p < 0.0001; HS+ve 0.98, p = 0.003), and more marked in HS-ve across all lobes except insula.

Conclusion: Overall, HS+ve patients showed more hippocampal, but also marginally more ipsilateral cerebral and cerebrocortical atrophy, greater ipsilateral hippocampal hypometabolism but similar ipsilateral cerebral cortical hypometabolism, confirming structural and functional differences between these groups.

Moving a unit online: a quantitative evaluation of student repsonses

In 2005, a unit was converted to ‘wholly online’ delivery mode, where all teaching occurred online. Student evaluation survey data for 2005 suggested that students rated many aspects of the wholly online unit delivery significantly lower than previously. For 2006, ten percent of the unit marks were dedicated to an assessed assignment activity based around an online discussion area. Based on student evaluation items common to the preand post-2006 period, overall student satisfaction with the unit returned to the same levels as prior to the introduction of wholly online delivery. These findings suggest that careful thought, but not necessarily major changes, may be required to avoid student disillusionment and maximise student learning outcomes when moving an existing unit to wholly online delivery. During 2005 and 2006, the same unit was included in a large survey to gauge students’ perceptions of studying wholly online units. The sub-set of respondents relating to this unit was found to have a good demographic match to the total unit enrolment. The survey included the following question item, ‘39: How satisfied have you been with this unit being offered wholly online?’, as an overall measure of student satisfaction with studying the unit in wholly online mode. Multivariate linear regression analysis was conducted with survey item 39 as the dependent variable. While the resultant regression model should not be interpreted literally as a formula for student satisfaction, it does suggest some areas for action to improve student satisfaction with studying this unit in wholly online mode.

Genetic variation in BEACON influences quantitative variation in metabolic syndrome-related phenotypes

The BEACON gene (also known as UBL5) was identified as differentially expressed between lean and obese Psammomys obesus, a polygenic animal model of obesity, type 2 diabetes, and dyslipidemia. The human homologue of BEACON is located on chromosome 19p, a region likely to contain genes affecting metabolic syndrome–related quantitative traits as established by linkage studies. To assess whether the human BEACON gene may be involved in influencing these traits, we exhaustively analyzed the complete gene for genetic variation in 40 unrelated individuals and identified four variants (three novel). The two more common variants were tested for association with a number of quantitative metabolic syndrome–related traits in two large cohorts of unrelated individuals. Significant associations were found between these variants and fat mass (P = 0.026), percentage of fat (P = 0.001), and waist-to-hip ratio (P = 0.031). The same variants were also associated with total cholesterol (P = 0.024), LDL cholesterol (P = 0.019), triglycerides (P = 0.006), and postglucose load insulin levels (P = 0.018). Multivariate analysis of these correlated phenotypes also yielded a highly significant association (P = 0.0004), suggesting that BEACON may influence phenotypic variation in metabolic syndrome–related traits.

A method for the quantitative analysis of the layering of HIV-related stigma

HIV-related stigma is regarded as one of the major barriers in the development of effective prevention and care programs; but the stigma associated with HIV stigma is not a singular entity. The stigma of the infection is layered with other stigmas, such as those associated with the routes of transmission (e.g., sex work and injecting drug use) and personal characteristics (e.g., race, religion, ethnicity and gender). In developing programs and policies to overcome HIV-related stigma, cognisance needs to be taken of all the sources of stigma, and how they may interact. A novel method is described for examining the layers of HIV/AIDS-related stigma, and secondary data are adapted to illustrate this. The importance of understanding the layering of stigma for the development of effective interventions is also discussed.