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This article presents information on a study related to mineralization of soil nitrogen in three forest communities from the New England region of New South Wales. The great rapidity with which readily labile nitrogen was mineralized during the first 2 weeks of incubation indicates a high potential for the production of inorganic nitrogen whenever environmental conditions are suitable. When the easily decomposable organic substrates are exhausted, presumably there follows a period during which slower mineralization processes build up a further supply of them, to be available for rapid oxidation to ammonium when favorable conditions again prevail. In this summer rainfall climate, the wetter and warmer months favor mineralization, leading to an increase in the field levels of inorganic nitrogen throughout spring and summer.

Objective: This research aims to (i) identify latent subgroups of ED presentations in Australian public EDs using a data-driven approach and (ii) compare clinical, socio-demographic and time-related characteristics of ED presentations broadly using the subgroups., Methods: We examined presentations to four public hospital EDs in Queensland from 2009 to 2014. An unsupervised machine learning algorithm, Clustering Large Applications, was used to cluster ED presentations., Results: There were six subgroups common across the EDs, primarily distinguishable by age, and subsequently by triage category, ED length of stay, arrival mode, departure status and several time-related attributes. Around 10% to 30% of the total presentations had high resource utilisation, with half of these from older patients (55+ years). ED resource utilisation per population was highest among the oldest cohort (75+ years). Children and young adults more frequently presented to the ED outside general-practitioner hours, mostly on Sundays. Older persons were more likely to present at any time, rather than specific hours, days or seasons. ED service performance measured against commonly used access-target indicators were rarely satisfied for older people and frequently satisfied for children., Conclusion: Clustering Large Applications is effective in finding latent groups in large-scale mixed-type data, as demonstrated in the present study. Six types of ED presentations were identified and described using clinically relevant characteristics. The present study provides evidence for policy makers in Australia to develop alternative ED models of care tailored around the care needs of the differing groups of patients and thereby supports the sustainable delivery of acute healthcare., (© 2021 Australasian College for Emergency Medicine.)

Objective: This research aims to (i) identify general practice-type (GP-type) presentations to EDs in South-East Queensland, Australia and (ii) compare and quantify the clinical, socio-demographic and time-varying characteristics between GP-type and non-GP-type presentations., Methods: Data were collected from presentations to four EDs in Queensland from 2009 to 2014. A modified version of the Australasian College for Emergency Medicine (ACEM) method for identifying GP-type ED presentations was used., Results: The four EDs have different proportions of GP-type presentations, between 7% and 33%. Between 2009 and 2014, the amount of GP-type presentations increased in three EDs, by between 5% and 16%, and decreased by 30% in the other ED. Different holidays, for example, the public holidays over the Christmas to New Year period, impact GP-type presentations. Over 50% of GP-type presentations occurred in those aged 0-34 years, and <1% were aged 85+ years. Injury-related diagnoses made up around 37% of the GP-type presentations, and around 13% did not wait for a diagnosis, averaged over the EDs. GP-type presentations are more likely to present to EDs outside standard general practitioner hours., Conclusions: Existing methods for identifying GP-type presentations have drawbacks, and modified methods are required to better identify these types of presentations. Temporal effects not previously investigated in Australian studies, such as holidays, are significantly associated with GP-type presentations. These findings aid strategic planning and interventions to support review of GP-type presentations, instead, in primary-care facilities, and such interventions may be assistive in some EDs more than others., (© 2021 Australasian College for Emergency Medicine.)

This study establishes a new method for estimating the monthly Average Population Present (APP) in Australian regions. Conventional population statistics, which enumerate people where they usually live, ignore the significant spatial mobility driving short term shifts in population numbers. Estimates of the temporary or ambient population of a region have several important applications including the provision of goods and services, emergency preparedness and serve as more appropriate denominators for a range of social statistics. This paper develops a flexible modelling framework to generate APP estimates from an integrated suite of conventional and novel data sources. The resultant APP estimates reveal the considerable seasonality in small area populations across Australia's regions alongside the contribution of domestic and international visitors as well as absent residents to the observed monthly variations. The modelling framework developed in the paper is conceived in a manner such that it can be adapted and re-deployed both for use with alternative data sources as well as other situational contexts for the estimation of temporary populations., Competing Interests: The authors have declared that no competing interests exist.

Objective: This research aimed to (i) assess the effects of time-varying predictors (day of the week, month, year, holiday, temperature) on daily ED presentations and (ii) compare the accuracy of five methods for forecasting ED presentations, including four statistical methods and a machine learning approach., Methods: Predictors of ED presentations were assessed using generalised additive models (GAMs), generalised linear models, multiple linear regression models, seasonal autoregressive integrated moving average models and random forest. The accuracy of short-term (14 days), mid-term (30 days) and long-term (365 days) forecasts were compared using two measures of forecasting error., Results: The data are the numbers of presentations to public hospital EDs in South-East Queensland, Australia, from 2009 to 2015. ED presentations are largely affected by year of presentation, and to a lesser extent by month, day of the week and holidays. Maximum daily temperature is also a significant predictor of ED presentations. Of the four statistical models considered, the GAM had the greatest forecasting accuracy, and produced consistent and coherent forecasts, likely due to its flexibility in modelling complex time-varying effects. The random forest machine learning approach had the lowest forecasting accuracy, likely due to overfitting the data., Conclusions: Calendar and temperature variables, not previously considered in the Australian literature, were found to significantly impact ED presentations. This study also demonstrates the potential of GAMs as a dual explanatory and forecasting method for the modelling, and more accurate prediction, of ED presentations., (© 2020 Australasian College for Emergency Medicine.)

The aim of the present study is to describe ACEM trainees' perspectives on assessment and feedback during their training. From May to July 2009, an anonymous Web-based survey on training and supervision in emergency medicine was conducted, addressing trainees' perceptions of mandatory assessments (primary examination, fellowship examination and mandatory trainee research requirement) and feedback at work. Qualitative data were analysed using grounded theory methodology--themes were identified by close examination of full text responses. In total, 622 trainees responded to the survey (response rate of 37%). Trainees report that general clinical supervision is adequate; however, direct supervision at the bedside and feedback could be significantly improved. They perceive that the primary examination is necessary, although they feel it is irrelevant to their development as emergency trainees and are keen for more clinically applied knowledge to be tested. They dislike mandatory trainee research, feel inadequately supported and distracted from other aspects of their training. The fellowship examination was overall thought to be fair; however, there were concerns with the time pressures and restrictions to the written component of the examination. Additionally, the structured clinical examination was popular, whereas short cases and long cases were very unpopular. ACEM trainees' views of training may help inform curriculum development, and might assist those providing education to improve local training programs., (© 2010 The Authors. EMA © 2010 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.)

Background: Equipoise is defined medically as a state of genuine uncertainty about the relative benefits of alternative treatment options. This study investigated individual and collective equipoise among vascular surgeons for controversial clinical questions to assess the feasibility of conducting randomized controlled trials., Methods: Vascular surgeons throughout Australia and New Zealand received a survey by mail., Results: Vascular surgeons (n=146, 77% response fraction) were able to quantify the strength of their treatment preferences and did so differentially between clinical scenarios using a simple scale. Almost one quarter (24%; 95% CI, 18%-32%) were completely undecided about whether carotid endarterectomy or carotid stenting was preferable to treat carotid stenosis in high-risk patients, indicating individual equipoise. In contrast, the vast majority of respondents (89%; 95% CI, 82%-93%) favored carotid endarterectomy over carotid stenting for average-risk patients, suggesting lack of community equipoise for this patient group. Similarly, there was lack of community equipoise for treatments for abdominal aortic aneurysm in high-risk patients with 88% (95% CI, 81%-92%) favoring a minimally invasive approach. Older respondents were consistently less willing to take part in randomized trials, with strength of treatment preference also independently predicting willingness to participate in 4 of 6 trials., Conclusions: Individual and community equipoise can be measured in a representative sample of surgeons as part of the feasibility assessment for future randomized controlled trials.

Background: Poor nutrition contributes to high rates of coronary heart disease among Australian Aboriginal populations. Since late 1993, the Aboriginal community described here has operated a healthy lifestyle program aimed at reducing the risk of chronic disease., Objective: We evaluated the effectiveness of a community-directed intervention program to reduce coronary heart disease risk through dietary modification., Design: Intervention processes included store management policy changes, health promotion activities, and nutrition education aimed at high-risk individuals. Dietary advice was focused on decreasing saturated fat and sugar intake and increasing fruit and vegetable intake. Evaluation of the program included conducting sequential, cross-sectional risk factor surveys at 2-y intervals; measuring fasting cholesterol, lipid-soluble antioxidants, and homocysteine concentrations; and assessing smoking status. Nutrient intakes were estimated from analysis of food turnover in the single community store., Results: There was a significant reduction in the prevalence of hypercholesterolemia (age-adjusted prevalences were 31%, 21%, and 15% at baseline, 2 y, and 4 y, respectively; P < 0.001). There were significant increases in plasma concentrations of alpha-tocopherol, lutein and zeaxanthin, cryptoxanthin, and beta-carotene across the population. Retinol and lycopene concentrations did not change significantly. Mean plasma homocysteine concentrations decreased by 3 micromol/L. There was no significant change in smoking prevalence between the 2 follow-up surveys. There was an increase in the density of fresh fruit and vegetables and carotenoids in the food supply at the community store., Conclusion: This community-directed dietary intervention program reduced the prevalence of coronary heart disease risk factors related to diet.

Context: A survey of medical students' experiences of sexual harassment during medical training., Objective: To assess the prevalence and nature of workplace sexual harassment as perceived by undergraduate medical students in order to address their learning needs concerning setting and maintaining sexual boundaries., Design: A questionnaire involving both quantitative and qualitative descriptions., Setting: A university medical school in Australia., Participants: The medical student population., Main Outcome Measures: Estimated prevalence of sexual harassment according to gender and year of training; frequency of sexual harassment reported by category of behaviour, year of training and gender; type of sexual harassment and alleged harasser reported by gender; frequency of sexual harassment reported by category of behaviour and alleged harasser., Results: Female students encountered an unacceptable amount of sexual harassment in medical training from fellow students, patients, faculty and doctors they worked with, which was perceived as affecting learning opportunities., Conclusion: Genderized sexual harassment exists in medical training. While both male and female students report episodes perceived as sexual harassment a difference in interpretation results in greater vulnerability for female students. Medical educators need to address issues of gender, sexual harassment, and the setting and maintaining of sexual boundaries in order to avoid a hostile learning environment.

Purpose: Currently no randomized studies show the relative morbidity and mortality of the open and endoluminal methods of abdominal aortic aneurysm (AAA) repair. The aim of this study was to analyze the outcome of two matched groups of patients with AAA, one undergoing open repair and the other undergoing endoluminal repair., Methods: Two groups of patients who had undergone repair of AAA by open technique (group 1) or by endoluminal methods (group 2) were compared. A historic control cohort of 27 patients was selected from 56 consecutive patients who underwent open repair of AAA between January 1991 and February 1992. Patients considered unsuitable for the endoluminal method on the basis of computed tomography and aortography were excluded (n=29). Between May 1992 and November 1994 prospective data were recorded for 62 consecutive patients who underwent endoluminal repair by tube or bifurcated endografts. Twenty-eight patients who had been specifically referred for endoluminal AAA repairs because of preexisting severe medical comorbidities were excluded. Six of the endoluminal cases had failure, requiring conversion to open operation, and were excluded for separate analysis, leaving 28 patients in group 2. Patients in both groups were thus fit and suitable for either open or endoluminal repair and were comparable in relation to age, sex, risk factors, dimensions, and form of AAA., Results: The mean values for operation time, blood loss, intensive care stay, and hospital stay for group 1 and group 2 were 2.6 versus 3.1 hours, 1422 versus 873 ml,* 1.8 versus 0.7 days,* and 12.4 versus 11.1 days, respectively (*p<0.05). Local/vascular complications occurred in 15% of patients in group 1 compared with 25% in group 2 (p=0.55), whereas remote/systemic complications occurred in 37% and 29%, respectively (p=0.3). Five of 28 patients in the endoluminal group had complications requiring early operative repair (n=3) or late revision (n=2). When comparison was made on an intention-to-treat basis (with failed procedures included), the incidence of local/vascular complications was significantly greater for endoluminal repair (p=0.047)., Conclusions: The incidence of systemic/remote complications was similar for the two groups in spite of significantly less blood loss and shorter intensive care unit stay with endoluminal repair. The incidence of local/vascular complications had a tendency to be higher for endoluminal compared with standard open method (and was significantly greater if failed procedures were included). In this early experience with prototype devices, patients who were medically suitable for open surgical procedures did not derive benefit from the less invasive endoluminal technique with respect to duration of operation, length of hospital stay, or perioperative morbidity and mortality. On the other hand, because they also did not have worse outcome, a randomized study is now justified in this group.

Public hospital laboratories have in the past fended off financial scrutiny and accountability on the grounds of their complexity and lack of compelling need. However, the cost of providing diagnostic laboratory services has now come under intense scrutiny because of budget reductions and options for private sector competition. Costing of pathology services is not difficult, but their organisation and outputs do have unique features that need to be understood and defined to ensure that the costing model used provides robust data that accurately reflects how resources are consumed. The cost data generated for diagnostic services can then be compared to the various benchmarks widely used for activity-based funding, such as the Commonwealth Medical Benefits Schedule and the pathology component of the AN-DRG Service Weights System, while the requirement and funding for other activities can be rationally determined.

The most important noncardiac consequence of use of the intra-aortic balloon pump (IABP) is associated iatrogenic vascular trauma. A retrospective analysis was undertaken of all patients at our institution (n = 90, mean age 60 years) who had insertion of an IABP over a 10-year period to assess the possibility of preoperative identification of patients at high risk of IABP associated vascular injury. Catheters were introduced via the common femoral artery (n = 84; 30 percutaneous, 4 open Seldinger technique, 50 via a dacron sleeve), external iliac artery (n = 2), and ascending aorta (n = 4). Thirty patients (33.3%) developed one or more complications, with 25 vascular complications, six major septic complications, and four deaths. Variables identified as significant risk factors for IABP complications were female gender (P < 0.01) and concomitant peripheral vascular disease (P < 0.05). Site of insertion, method or difficulty of insertion, age, duration of counterpulsation, and use of anticoagulation and antibiotics did not significantly affect the incidence of vascular complications (P > 0.05). In conclusion, prior to cardiac surgery, we recommend screening for peripheral vascular disease to identify patients at increased risk of complications should IABP counterpulsation be required. Ankle/brachial systolic pressure indices may be used to detect subclinical disease.

An overview is presented of a number of astrometry and astrophysics programs based on radio sources from the Parkes 2.7 GHz catalogues. The programs cover the optical identification and spectroscopy of flat-spectrum Parkes sources and the determination of their milliarc-second radio structures and positions. Work is also in progress to tie together the radio and Hipparcos positional reference frames. A parallel program of radio and optical astrometry of southern radio stars is also under way.

Commonly used diagnostic biochemical tests were performed on blood samples from a small group of Aboriginal Australians. Reference ranges derived from a white urban population appear to be applicable to the study group for the correct interpretation of plasma electrolyte, urea, creatinine, urate, albumin and calcium levels. Care should be exercised in the use of the plasma urea level alone as a screening test for renal function. Results for the plasma enzyme activities of both aspartate and alanine aminotransferases suggest that the reference ranges currently used by laboratories may be inappropriate for correct diagnostic interpretation. Thyroid function tests showed that plasma levels of total thyroxine, total triiodothyronine, and thyroxine-binding globulin were lower than normal white values in this group of tribal Aboriginals; this suggests that the reference ranges derived from a white population are misleading for diagnostic purposes.

This paper reports a remarkable case of venereal disease. It discusses the serious implications and enormous difficulties of control in an Aboriginal community in which striking cultural practices play a unique and major role in disease transmission. Despite known aetiology and the ready availability of inexpensive treatment, patients continue to suffer whilst health education remains extremely difficult.