Vacuum cleaner emissions as a source of indoor exposure to airborne particles and bacteria

Vacuuming can be a source of indoor exposure to biological and non-biological aerosols, although there is little data that describes the magnitude of emissions from the vacuum cleaner itself. We therefore sought to quantify emission rates of particles and bacteria from a large group of vacuum cleaners and investigate their potential determinants, including temperature, dust bags, exhaust filters, price and age. Emissions of particles between 0.009 and 20 µm and bacteria were measured from 21 vacuums. Ultrafine (<100 nm) particle emission rates ranged from 4.0 × 10^6 to 1.1 × 10^11 particles min-1. Emission of 0.54 to 20 µm particles ranged from 4.0 × 10^4 to 1.2 × 10^9 particles min-1. PM2.5 emissions were between 2.4 × 10-1 and 5.4 × 10^3 µg min-1. Bacteria emissions ranged from 0 to 7.4 × 10^5 bacteria min-1 and were poorly correlated with dust bag bacteria content and particle emissions. Large variability in emission of all parameters was observed across the 21 vacuums we assessed, which was largely not attributable to the range of determinant factors we assessed. Vacuum cleaner emissions contribute to indoor exposure to non-biological and biological aerosols when vacuuming, and this may vary markedly depending on the vacuum used.

Development of novel vaccine strategies to prevent genital tract chlamydial infections

Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection in the developed world and the leading cause of preventable blindness worldwide. As reported by the World Health Organization in 2001, there are approximately 92 million new infections detected annually, costing health systems billions of dollars to treat not only the acute infection, but also to treat infection-associated sequelae. The majority of genital infections are asymptomatic, with 50-70% going undetected. Genital tract infections can be easily treated with antibiotics when detected. Lack of treatment can lead to the development of pelvic inflammatory disease, ectopic pregnancies and tubal factor infertility in women and epididymitis and prostatitis in men. With infection rates on the continual rise and the large number of infections going undetected, there is a need to develop an efficacious vaccine which prevents not only infection, but also the development of infection-associated pathology. Before a vaccine can be developed and administered, the pathogenesis of chlamydial infections needs to be fully understood. This includes the kinetics of ascending infection and the effects of inoculating dose on ascension and development of pathology. The first aim in this study was to examine these factors in a murine model. Female BALB/c mice were infected intravaginally with varying doses of C. muridarum, the mouse variant of human C. trachomatis, and the ascension of infection along the reproductive tract and the time-course of infection-associated pathology development, including inflammatory cell infiltration, pyosalpinx and hydrosalpinx, were determined. It was found that while the inoculating dose did affect the rate and degree of infection, it did not affect any of the pathological parameters examined. This highlighted that the sexual transmission dose may have minimal effect on the development of reproductive sequelae. The results of the first section enabled further studies presented here to use an optimal inoculating dose that would ascend the reproductive tract and cause pathology development, so that vaccine efficacy could be determined. There has been a large amount of research into the development of an efficacious vaccine against genital tract chlamydial infections, with little success. However, there have been no studies examining the effects of the timing of vaccination, including the effects of vaccination during an active genital infection, or after clearance of a previous infection. These are important factors that need to be examined, as it is not yet known whether immunization will enhance not only the individual's immune response, but also pathology development. It is also unknown whether any enhancement of the immune responses will cause the Chlamydia to enter a dormant, persistent state, and possibly further enhance any pathology development. The second section of this study aimed to determine if vaccination during an active genital tract infection, or after clearance of a primary infection, enhanced the murine immune responses and whether any enhanced or reduced pathology occurred. Naïve, actively infected, or previously infected animals were immunized intranasally or transcutaneously with the adjuvants cholera toxin and CpG-ODN in combination with either the major outer membrane protein (MOMP) of C. muridarum, or MOMP and ribonucleotide reductase small chain protein (NrdB) of C. muridarum. It was found that the systemic immune responses in actively or previously infected mice were altered in comparison to animals immunized naïve with the same combinations, however mucosal antibodies were not enhanced. It was also found that there was no difference in pathology development between any of the groups. This suggests that immunization of individuals who may have an asymptomatic infection, or may have been previously exposed to a genital infection, may not benefit from vaccination in terms of enhanced immune responses against re-exposure. The final section of this study aimed to determine if the vaccination regimes mentioned above caused in vivo persistence of C. muridarum in the upper reproductive tracts of mice. As there has been no characterization of C. muridarum persistence in vitro, either ultrastructurally or via transcriptome analysis, this was the first aim of this section. Once it had been shown that C. muridarum could be induced into a persistent state, the gene transcriptional profiles of the selected persistent marker genes were used to determine if persistent infections were indeed present in the upper reproductive tracts of the mice. We found that intranasal immunization during an active infection induced persistent infections in the oviducts, but not the uterine horns, and that intranasal immunization after clearance of infection, caused persistent infections in both the uterine horns and the oviducts of the mice. This is a significant finding, not only because it is the first time that C. muridarum persistence has been characterized in vitro, but also due to the fact that there is minimal characterization of in vivo persistence of any chlamydial species. It is possible that the induction of persistent infections in the reproductive tract might enhance the development of pathology and thereby enhance the risk of infertility, factors that need to be prevented by vaccination, not enhanced. Overall, this study has shown that the inoculating dose does not affect pathology development in the female reproductive tract of infected mice, but does alter the degree and rate of ascending infection. It has also been shown that intranasal immunization during an active genital infection, or after clearance of one, induces persistent infections in the uterine horns and oviducts of mice. This suggests that potential vaccine candidates will need to have these factors closely examined before progressing to clinical trials. This is significant, because if the same situation occurs in humans, a vaccine administered to an asymptomatic, or previously exposed individual may not afford any extra protection and may in fact enhance the risk of development of infection-associated sequelae. This suggests that a vaccine may serve the community better if administered before the commencement of sexual activity.

Child welfare policy and practice on children’s exposure to domestic violence

There are emerging movements in several countries to improve policy and practice to protect children from exposure to domestic violence. These movements have resulted in the collection of new data on EDV and the design and implementation of new child welfare policies and practices. To assist with the development of child welfare practice, this article summarizes current knowledge on the prevalence of EDV, and on child welfare services policies and practices that may hold promise for reducing the frequency and impact of EDV on children. We focus on Australia, Canada, and the United States, as these countries share a similar socio-legal context, a long history of enacting and expanding legislation about reporting of maltreatment, debates regarding the application of reporting laws to EDV, and new child welfare practices that show promise for responding more effectively to EDV.

Commentaries and Responses to "The Driver Behaviour Questionnaire as a predictor of accidents: A meta-analysis" [Commentaries lead by Anders af Wahlberg; Responses lead by J.C.F. de Winter]

The following discussion is in response to a 2010 article published in the Journal of Safety Research by J.C.F. de Winter and D. Dodou entitled “The Driver Behaviour Questionnaire as a predictor of accidents: A meta-analysis” (Volume 41, Number 6, pp. 463-470, available on sciencedirect.com). The editors are pleased to provide a forum for this exchange and welcome further comments.

Learning to lead : a social justice perspective on understanding elementary teacher leadership in Papua New Guinea

Leadership in elementary education is currently recognized as a political imperative in Papua New Guinea (PNG), as the nation develops strategies towards equitable access to schooling. One recent initiative aimed at building educational leadership was an intensive Australian Leadership Award Fellowship (ALAF) program funded by AusAID, involving a group of 10 teacher trainers from PNG. As part their involvement participants completed self-authored journal entries at the beginning and end of the leadership program. Participants were also involved in focus groups after completion of the initiative. Referring to the experiences of these teacher trainers, this paper draws on Nancy Fraser’s (2005, 2008) social justice framework to examine participants’ views of what constituted effective leadership in elementary education in PNG and how these views may have changed throughout the ALAF program. Key findings of this study included participants’ emphasis on relationships and valuing people in elementary education leadership contexts, participants’ concern about economic/financial barriers to effective leadership in the PNG context and participants’ perception of research as a way to support leadership roles.

An estimation of crash risks using a log-linear model and the induced exposure technique

Prevention and safety promotion programmes. Traditionally, in-depth investigations of crash risks are conducted using exposure controlled study or case-control methodology. However, these studies need either observational data for control cases or exogenous exposure data like vehicle-kilometres travel, entry flow or product of conflicting flow for a particular traffic location, or a traffic site. These data are not readily available and often require extensive data collection effort on a system-wide basis. Aim: The objective of this research is to propose an alternative methodology to investigate crash risks of a road user group in different circumstances using readily available traffic police crash data. Methods: This study employs a combination of a log-linear model and the quasi-induced exposure technique to estimate crash risks of a road user group. While the log-linear model reveals the significant interactions and thus the prevalence of crashes of a road user group under various sets of traffic, environmental and roadway factors, the quasi-induced exposure technique estimates relative exposure of that road user in the same set of explanatory variables. Therefore, the combination of these two techniques provides relative measures of crash risks under various influences of roadway, environmental and traffic conditions. The proposed methodology has been illustrated using Brisbane motorcycle crash data of five years. Results: Interpretations of results on different combination of interactive factors show that the poor conspicuity of motorcycles is a predominant cause of motorcycle crashes. Inability of other drivers to correctly judge the speed and distance of an oncoming motorcyclist is also evident in right-of-way violation motorcycle crashes at intersections. Discussion and Conclusions: The combination of a log-linear model and the induced exposure technique is a promising methodology and can be applied to better estimate crash risks of other road users. This study also highlights the importance of considering interaction effects to better understand hazardous situations. A further study on the comparison between the proposed methodology and case-control method would be useful.

Long term exposure to asbestos satisfies test for causation

Background In Booth v Amaca Pty Ltd and Amaba Pty Ltd,1 the New South Wales Dust Diseases Tribunal awarded a retired motor mechanic $326 640 in damages for his malignant pleural mesothelioma allegedly caused by exposure to asbestos through working with the brake linings manufactured by the defendants. The evidence before the Tribunal was that the plaintiff had been exposed to asbestos prior to working as a mechanic from home renovations when he was a child and loading a truck as a youth. However, as a mechanic he had been exposed to asbestos in brake linings on which he worked from 1953 to 1983. Curtis DCJ held at [172] that the asbestos from the brake linings ‘materially contributed to [the plaintiff’s] contraction of mesothelioma’. This decision was based upon acceptance that the effect of exposure to asbestos on the development of mesothelioma was cumulative and rejection of theory that a single fibre of asbestos can cause the disease...

Exposure to hot and cold temperatures and ambulance attendances in Brisbane, Australia: A time series study

ABSTRACT Objectives: To investigate the effect of hot and cold temperatures on ambulance attendances. Design: An ecological time series study. Setting and participants: The study was conducted in Brisbane, Australia. We collected information on 783 935 daily ambulance attendances, along with data of associated meteorological variables and air pollutants, for the period of 2000–2007. Outcome measures: The total number of ambulance attendances was examined, along with those related to cardiovascular, respiratory and other non-traumatic conditions. Generalised additive models were used to assess the relationship between daily mean temperature and the number of ambulance attendances. Results: There were statistically significant relationships between mean temperature and ambulance attendances for all categories. Acute heat effects were found with a 1.17% (95% CI: 0.86%, 1.48%) increase in total attendances for 1 °C increase above threshold (0–1 days lag). Cold effects were delayed and longer lasting with a 1.30% (0.87%, 1.73%) increase in total attendances for a 1 °C decrease below the threshold (2–15 days lag). Harvesting was observed following initial acute periods of heat effects, but not for cold effects. Conclusions: This study shows that both hot and cold temperatures led to increases in ambulance attendances for different medical conditions. Our findings support the notion that ambulance attendance records are a valid and timely source of data for use in the development of local weather/health early warning systems.

Exposure to hot and cold temperatures and ambulance attendances in Brisbane, Australia

Objectives: To investigate the effect of hot and cold temperatures on ambulance attendances. Design: An ecological time series study. Setting and participants: The study was conducted in Brisbane, Australia. We collected information on 783 935 daily ambulance attendances, along with data of associated meteorological variables and air pollutants, for the period of 2000–2007. Outcome measures: The total number of ambulance attendances was examined, along with those related to cardiovascular, respiratory and other non-traumatic conditions. Generalised additive models were used to assess the relationship between daily mean temperature and the number of ambulance attendances. Results: There were statistically significant relationships between mean temperature and ambulance attendances for all categories. Acute heat effects were found with a 1.17% (95% CI: 0.86%, 1.48%) increase in total attendances for 1 °C increase above threshold (0–1 days lag). Cold effects were delayed and longer lasting with a 1.30% (0.87%, 1.73%) increase in total attendances for a 1 °C decrease below the threshold (2–15 days lag). Harvesting was observed following initial acute periods of heat effects, but not for cold effects. Conclusions: This study shows that both hot and cold temperatures led to increases in ambulance attendances for different medical conditions. Our findings support the notion that ambulance attendance records are a valid and timely source of data for use in the development of local weather/health early warning systems.

Examining Exposure of Motorcycles at Signalized Intersections

Crash statistics in Singapore from 2001 to 2005 have shown that motorcycles are involved in about 54% of intersection crashes. The overall involvement of motorcycles in crashes as the not-at-fault party is about 43% but at intersections, the corresponding percentage is increased to 57%. Quasi-induced exposure estimates show that the motorcycle exposure rate at signalized intersections is 41.7% even though motorcycles account for only 19% of the vehicle population. This study seeks to examine in greater details, the problem of motorcycle exposure at signalized intersections. In particular, the exposure arising from potential crashes with red light running vehicles from the conflicting stream at four signalized intersections is investigated. The results show that motorcycles are more exposed because they tend to accumulate near the stop-line during the red phase to facilitate an earlier discharge during the initial period of the green which is the more vulnerable period. At sites where there are more weaving opportunities because the lanes are wider or where there are exclusive right-turn lanes, the accumulation is higher and hence an increased exposure is observed. The analysis also shows that the presence of heavy vehicles tends to decrease motorcycle exposure as their weaving opportunities become restricted as well as there is a greater reluctance for them to weave past or queue alongside the heavy vehicles and their effects intensify for narrower lane width.