Prevention of the Occupational Silicosis Epidemic in Australia: What Do Those Who Assess Workplace Health Risk Think Should Be Done Now?

An Australian National Dust Disease Taskforce was established to address the re-emergence of occupational lung disease, in particular silicosis. Exposure to respirable crystalline silica (RCS) occurs in various industries in Australia. We asked occupational hygienists about their practical experiences and perspectives on RCS exposure and regulatory action. A total of 105 members of the Australian Institute of Occupational Hygienists completed an anonymous questionnaire, which addressed individual characteristics, experience, perceived level of employer awareness, effectiveness of current regulation, and recommendations for improvement, across three main industrial sectors. Based on professional experience, 71% were concerned about the potential for RCS over-exposure. Barriers to adequate exposure control included lack of management commitment and financial resources. The employment of specialist occupational hygiene inspectors was considered to be the most effective regulatory strategy. Given the large number of exposed workers in the construction industry, with only a moderate awareness, there is the potential for significant cost shifting of the burden of occupational lung disease from employers on to individuals and the public health system. A nationally consistent approach to RCS exposure control across all industrial sectors is now recommended, with an increased focus on measuring and controlling exposure.

Effects of Movement for High Time-Bandwidths in Batched Pulse Compression Range-Doppler Radar.

Radar detection and track building performance is an essential part of a radar system. A high realized coherent integration gain often contributes to an improved performance. This is essential to the successful detection and tracking of weak moving targets. However, the actual movement within the coherent processing interval can introduce range walk effects. The processing will then result in range and Doppler frequency resolutions that become finer than a single moving point scatterer's spread over range and-often not considered-over Doppler frequency. In particular for a wide instantaneous bandwidth, the impact on the achievable integration gain can become severe already for a constant effective velocity. Therefore, high desired integration gains as required in passive radar are not easily achieved against relatively fast moving targets. The main intent of this article is to present the movement effects on a classical range-Doppler analysis to give an insight on the achievable performance and to quantify otherwise appearing degradations. Interestingly, a classical analysis of experimental datasets evaluated from a DVB-T based passive radar measurement campaign even resolved the fluctuation of a target response within the instantaneously processed bandwidth. The findings strengthen the need for advanced processing methods that can at least partly address individual implications of fast moving targets in real-time applications properly.

Expostats: A Bayesian Toolkit to Aid the Interpretation of Occupational Exposure Measurements.

INTRODUCTION: Interpretation of exposure measurements has evolved into a framework based on the lognormal distribution. Most available practical tools are based on traditional frequentist statistical procedures that do not satisfactorily account for censored data and are not amenable to simple probabilistic risk statements. Bayesian methods offer promising solutions to these challenges. Such methods have been proposed in the literature but are not widely and freely available to practitioners. METHODS: A set of computer applications were developed aimed at answering typical inferential questions that are important to occupational health practitioners: Is a group of workers compliant with an occupational exposure limit? Are some individuals within this group likely to experience substantially higher exposure than its average member? How does an intervention influence the distribution of exposures? These questions were addressed using Bayesian models, simultaneously accounting for left, right, and interval-censored data with multiple censoring points. The models are estimated using the JAGS Gibbs sampler called through the R statistical package. RESULTS: The Expostats toolkit is freely available from www.expostats.ca as four tools accessible through a Web application, an offline standalone application or algorithms. The tools include a variety of calculations and graphical outputs useful according to current practices in analysis and interpretation of exposure measurements collected by occupational hygienists. Tool1 and its simplified version Tool1 Express focus on inferences from data from a similarly exposed group. Tool2 evaluates within- and between-worker components of variability, as well as the probability that an individual worker might be overexposed. Tool3 compares exposure data across groups, e.g. evaluates the effect of an intervention. Uncertainty management includes the calculation of credible intervals and produces probabilistic statements about the exposure metrics (e.g. probability that over 5% of exposures are above a limit). DISCUSSION: Expostats is the first freely available toolkit that leverages the flexibility of Bayesian analysis to perform an extensive list of calculations recommended in several international guidelines on the practice of occupational hygiene.

Red-cell and platelet alloimmunisation in pregnancy.

The management of red-cell alloimmunisation has been revolutionised by the widespread use of anti-D administration for mothers who are rhesus negative, and the availability of non-invasive, ultrasound-based techniques for reliable detection of moderate-to-severe fetal anaemia. With reduced frequency of alloimmunisation to the D antigen, antibodies to c and Kell antigen are increasingly responsible for red-cell alloimmunisation. Ultrasound-based, non-invasive diagnosis is now so reliable that invasive techniques are sparingly used to detect significant fetal anaemia. Treatment of fetal anaemia using ultrasound-guided intravascular transfusions is highly successful. Advances in molecular biology have led to the successful determination of fetal blood group using free fetal DNA from maternal blood. This development is highly likely to allow use of anti-D in only those pregnant women carrying rhesus-positive fetuses. Sensitisation to non-D group antibodies continues to occur owing to the lack of available prophylaxis for other blood-group antigens.

Blinded, multi-center validation of EEG and rating scales in identifying ADHD within a clinical sample.

Previous validation studies of attention deficit/hyperactivity disorder (ADHD) assessment by rating scales or EEG have provided Class-IV evidence per standards of the American Academy of Neurology. To investigate clinical applications, we collected Class-I evidence, namely from a blinded, prospective, multi-center study of a representative clinical sample categorized with a clinical standard. Participating males (101) and females (58) aged 6 to 18 had presented to one of four psychiatric and pediatric clinics because of the suspected presence of attention and behavior problems. DSM-IV diagnosis was performed by clinicians assisted with a semi-structured clinical interview. EEG (theta/beta ratio) and ratings scales (Conners Rating Scales-Revised and ADHD Rating Scales-IV) were collected separately in a blinded protocol. ADHD prevalence in the clinical sample was 61%, whereas the remainder had other childhood/adolescent disorders or no diagnosis. Comorbidities were observed in 66% of ADHD patients and included mood, anxiety, disruptive, and learning disorders at rates similar to previous findings. EEG identified ADHD with 87% sensitivity and 94% specificity. Rating scales provided sensitivity of 38-79% and specificity of 13-61%. While parent or teacher identification of ADHD by rating scales was reduced in accuracy when applied to a diverse clinical sample, theta/beta ratio changes remained consistent with the clinician's ADHD diagnosis. Because theta/beta ratio changes do not identify comorbidities or alternative diagnoses, the results do not support the use of EEG as a stand-alone diagnostic and should be limited to the interpretation that EEG may complement a clinical evaluation for ADHD.