Phylogeny affects estimation of metabolic scaling in mammals

The relationship between body size and metabolic rate is a crucial issue in organismal biology and evolution. There has been considerable debate over whether the scaling exponent of the relationship is 0.75 (Kleiber’s Law) or 0.67. Here we show that determination of this exponent for mammals depends on both the evolutionary tree and the regression model used in the comparative analysis. For example, more recent molecular-based phylogenies tend to support a 0.67 exponent, whereas older phylogenies, mostly based on morphological data, suggest a 0.75 exponent. However, molecular phylogenies yield more variable results than morphological phylogenies and thus are not currently helping to resolve the issue.

Fracture risk (FRISK) score : Geelong Osteoporosis Study

Purpose: To develop and evaluate a fracture risk (FRISK) score based on multiple-site bone mineral density (BMD) measurements and other risk factors, to enable prediction of future fracture occurrence.

Materials and Methods: All participants gave written informed consent, and the study was approved by the Barwon Health Research and Ethics Advisory Committee. BMD was measured at the femoral neck and spine in two concurrently recruited groups: women 60 years of age or older who had sustained a low-trauma fracture of the hip, spine, humerus or distal forearm during a 2-year ascertainment period (n = 231; mean age, 74 years ± 7 [standard deviation]) and a population-based random sample of women who had not sustained a fracture during the recruitment period (n = 448; mean age, 72 years ± 8). Falls in the previous year and the number of self-reported fractures in adult life were recorded. Coefficients of a multiple logistic regression model were used as weightings for a combined model. A longitudinal population-based sample was used to assess the fracture risk equation (n = 600; median age, 74 years; interquartile range, 67–82 years).

Results: The FRISK score was obtained from the following equation: 9.304 − 4.735BMDSP − 4.530BMDFN + 1.127FS + 0.344NPF + 0.037W, where BMDSP is spinal BMD (in grams per square centimeter), BMDFN is femoral neck BMD, FS is falls score, NPF is number of previous fractures, and W is weight (in kilograms). The FRISK score successfully predicted 75% of fractures 2 years after baseline measurements in subjects in the longitudinal study with 68% specificity.

Conclusion: This study resulted in the derivation of a fracture risk score that successfully predicted 75% of fractures 2 years after baseline.

The impact of a computerised consolidation accounting package (CCAP) on student performance

Purpose – The purpose of this paper is to investigate the association between the use of a computerised learning tool (specifically designed to teach consolidation accounting) and student performance in the final examination of an undergraduate accounting unit on Corporate Accounting.

Design/methodology/approach – A regression model was developed to analyse 1,103 observations of assignment and examination scores, collected over three semesters, to test the central proposition that computer assisted learning enhances student learning outcomes and performance in the exam.

Findings – The results show a positive and significant relationship between the computerised accounting assignment on consolidated accounting (linked to usage of the computerised tool) and the consolidation question in the final examination. The findings suggest that the computerised consolidation accounting package (CCAP) assists students to understand the concepts underpinning consolidation accounting.

Research limitations/implications – The data were collected from a single institution, which may not represent the population of accounting students. Due to ethical obligations, the study lacked a control group that would have allowed meaningful comparison and assessment of student performance. Furthermore, whilst the findings in this study were able to demonstrate a positive association between the CCAP and exam performance, it is unable to determine the quality and depth of the learning experience from using the CCAP.

Practical implications – The present study found that a CCAP and its usage has the potential to positively impact student performance on assessment tasks on subject matter similar to concepts contained the computer package. Such findings may encourage instructors to seek ways of incorporating learning technologies in the pedagogical design.

Originality/value – This is believed to be one the few papers that has exclusively studied the impact of a specific CCAP and a specific segment in accounting education (consolidation accounting) using direct measures, CCAP assignment score and the final examination score for a question dedicated to consolidation accounting.

Computer reminders for chlamydia screening in general practice : a randomized controlled trial

Background: Chlamydia notifications are increasing in Australia, and the use of a computer alert prompting general practitioners to test young women is a potential way to increase opportunistic chlamydia testing. The aim of this trial was to determine the effectiveness of a computer alert in general practice on chlamydia testing in young women.

Methods: In 2006, clinics (n = 68) in Melbourne, Australia were cluster randomized into 2 groups: the intervention group received a computerized alert advising the general practitioner to discuss chlamydia testing with their patient which popped up when the medical record of a 16- to 24-year-old woman was opened; the control group received no alert. The outcome was whether or not that patient received a chlamydia test at the level of a single consultation with an eligible patient. A mixed effects logistic regression model adjusting for clustering was used to assess the impact of the alert on the proportion of women tested for chlamydia during the trial period.

Results: Testing increased from 8.3% (95% confidence interval (CI): 6.8, 9.8) to 12.2% (95% CI: 9.1, 15.3) (P < 0.01) in the intervention group, and from 8.8% (95% CI: 6.8, 10.7) to 10.6% (95% CI: 8.5, 12.7) (P < 0.01) in the control group. Overall, the intervention group had a 27% (OR = 1.3; 95% CI: 1.1, 1.4) greater increase in testing.

Conclusion: The results of this study suggest that alerts alone may not be sufficient to get chlamydia testing levels up sufficiently high enough to have an impact on the burden of chlamydia in the population but that they could be included as part of a more complex intervention.

The epidemiology of cryptosporidiosis in New Zealand, 1997-2006

Aims New Zealand has a high incidence of cryptosporidiosis compared to other developed countries. This study aimed to describe the epidemiology of this disease in detail and to identify potential risk factors.

Methods We analysed anonymous cryptosporidiosis notification (1997–2006) and hospitalisation data (1996–2006). Cases were designated as “urban” or “rural” and assigned a deprivation level based on their home address. Association between disease rates and animal density was studied using a simple linear regression model, at the territorial authority level.

Results Over the 10-year period 1997–2006, the average annual rate of notified cryptosporidiosis was 22.0 cases per 100,000 population. The number of hospitalisations was equivalent to 3.6% of the notified cases. There was only 1 reported fatality. The annual incidence of infection appeared fairly stable, but showed marked seasonality with a peak rate in spring (September–November in New Zealand). The highest rates were among Europeans, children 0–9 years of age, and those living in low deprivation areas. Notification rates showed large geographic variations, with rates in rural areas 2.8 times higher than in urban areas, and with rural areas also experiencing the most pronounced spring peak. At the territorial authority (TA) level, rates were also correlated with farm animal density.

Conclusions Most transmission of Cryptosporidium in New Zealand appears to be zoonotic: from farm animals to humans. Prevention should focus on reducing transmission in rural setting, though more research is needed to identify which strategies are likely to be most effective in that environment.

The epidemiology of giardiasis in New Zealand, 1997-2006

Aims New Zealand has a higher incidence rate of giardiasis than other developed countries. This study aimed to describe the epidemiology of this disease in detail and to identify potential risk factors.

Methods We analysed anonymous giardiasis notification (1997–2006) and hospitalisation data (1990–2006). Cases were designated as urban or rural and assigned a deprivation level based on their home address. Association between disease rates and animal density was studied using a simple linear regression model, at the territorial authority (TA) level.

Results Over the 10-year period 1997–2006 the average annual rate of notified giardiasis was 44.1 cases per 100,000 population. The number of hospitalisations was equivalent to 1.7% of the notified cases. There were 2 reported fatalities. The annual incidence of notified cases declined over this period whereas hospitalisations remained fairly constant. Giardiasis showed little seasonality. The highest rates were among children 0–9 years old, those 30–39 years old, Europeans, and those living in low deprivation areas. Notification rates were slightly higher in rural areas. The correlation between giardiasis and farm animal density was not significant at the TA level.

Conclusions The public health importance of giardiasis to New Zealand mainly comes from its relatively high rates in this country. The distribution of cases is consistent with largely anthroponotic (human) reservoirs, with a relatively small contribution from zoonotic sources in rural environments and a modest contribution from overseas travel. Prevention efforts could include continuing efforts to improve hand washing, nappy handling, and other hygiene measures and travel health advice relating to enteric infections.

Positive association between ambient temperature and salmonellosis notifications in New Zealand, 1965-2006

Objective: To investigate the temporal relationship between the monthly count of salmonellosis notifications and the monthly average temperature in New Zealand during the period 1965–2006.

Methods: A negative binomial regression model was used to analyse monthly average ambient temperature and salmonellosis notifications in New Zealand between 1965 and 2006.

Results: A 1°C increase in monthly average ambient temperature was associated with a 15% increase in salmonellosis notifications within the same month (IRR 1.15; 95% CI 1.07 – 1.24).

Conclusion: The positive association found in this study between temperature and salmonellosis notifications in New Zealand is consistent with the results of studies conducted in other countries. New Zealand is projected to experience an increase in temperature due to climate change. Therefore, all other things being equal, climate change could increase salmonellosis notifications in New Zealand.

Implications: This association between temperature and salmonellosis should be considered when developing public health plans and climate change adaptation policies. Strategically, existing food safety programs to prevent salmonellosis could be intensified during warmer periods. As the association was strongest within the same month, focusing on improving food handling and storage during this time period may assist in climate change adaptation in New Zealand.

Tuberculosis associated with household crowding in a developed country

Background: Tuberculosis (TB) remains an important infectious disease in New Zealand (NZ) and globally, but risk factors for transmission are still poorly understood. This research aimed to identify whether household crowding contributes to TB transmission in NZ.

Methods: This ecological study used TB surveillance and census data to calculate TB incidence rates by census area unit (CAU). Census data were used to determine CAU characteristics including proportion of household crowding (a bedroom deficit of one or more), proportion of population who are migrants born in high-TB-incidence countries, median household income, and deprivation level. A negative binomial regression model was used to estimate the association between TB incidence and household crowding.

Results: The analysis included 1898 notified TB cases for the 2000–4 period. Univariate analysis showed TB incidence at the CAU level was associated with household crowding, for the total population and for all ethnic and age groups. After adjusting for the covariates of household income, existing TB burden, and proportion of migrants from high-TB-incidence countries, multivariate analysis showed statistically significant associations between TB incidence and household crowding. The incidence rate ratio (IRR) was 1.05 (95% CI 1.02 to 1.08) in the total population and 1.08 (95% CI 1.04 to 1.12) for NZ-born people <40 years.

Conclusion: At the CAU level, TB incidence in NZ is associated with household crowding. An individual-based study (e.g. case–control) in recently infected cases (detected by molecular epidemiology techniques) is suggested to complement these findings. Reducing or eliminating household crowding could decrease TB incidence in NZ and globally.

Application of an Adaptive Neural Network to Medical Decision Support

Medical diagnostic and prognostic problems are prime examples of decision making in the face of uncertainty. In this paper, we investigate the applicability of the Fuzzy ARTMAP neural network as an intelligent decision support system in clinical medicine. In particular, Fuzzy ARTMAP is employed as a predictive model for prognosis of complications in patients admitted to the Coronary Care Units. A number of off-line and on-line experiments have been conducted with various network parameter settings, training methods, and learning rules. The results are compared with those from other systems including the logistic regression model. In addition, the outcomes of a set of on-line learning experiments revealed the potential of employing Fuzzy ARTMAP as an autono-mously learning system that is able to learn perpetually and, at the same time, to provide useful decision support.

Internal audit attributes and external audit's reliance on internal audit : implications for audit fees

This study aims to examine two aspects of internal audit quality, namely internal audit competency and internal audit contribution to financial statement audits. Consistent with the substitution view, this study predicts a negative relationship between the competency aspects of internal audit (the tenure of the existence of internal audit in the organization, internal audit staff expertise in IT and computer skills, training hours, internal audit staff professional certifications in accounting and auditing, and internal audit staff experience in auditing) and audit fees. Second, this study tests whether the contribution of internal auditors to financial statement audit reduces audit fees. The data analysis is based on a cross-sectional regression model with observations of 73 public-listed firms in Malaysia, which include publicly available data matched with survey responses from their internal and external auditors. The results of the study suggest that the competency of internal audit, namely the tenure of the existence of internal audit in the organization, training, internal audit staff prior experience in auditing and accounting, and certifications are associated with lower audit fees. Our findings for both aspects of internal audit quality (competency and internal audit contribution) lend support to the substitution view for explaining the links between internal audit quality and audit fees.

Risk factors for recurrent Mycobacterium ulcerans disease after exclusive surgical treatment in an Australian cohort

Objective: To describe risk factors for recurrence after exclusive surgical treatment of Mycobacterium ulcerans infection. Design, setting and participants: Prospective observational cohort study of all M. ulcerans cases managed with surgery alone at Barwon Health, a tertiary referral hospital, from 1 January 1998 to 31 December 2011. A random-effects Poisson regression model was used to assess rates and associations of treatment failure. Main outcome measures: Rates of treatment failure and rate ratios (RRs) for factors associated with treatment failure. Results: Of 192 patients with M. ulcerans infection, 50 (26%) had exclusive surgical treatment. Median age was 65.0 years (interquartile range [IQR], 45.5-77.7 years), and median duration of symptoms was 46 days (IQR, 26-90 days). There were 20 recurrences in 16 patients. For first lesions, the recurrence incidence rate was 41.8 (95% CI, 25.6-68.2) per 100 person-years, and median time to recurrence was 50 days (IQR, 30-171 days). Recurrence occurred ≤ 3 cm from the original lesion in 13 cases, and >3 cm in nine. On univariable analysis, age ≥60 years (RR 13.84; 95% CI, 2.21-86.68; P< 0.01), distal lesions (RR, 20.43; 95% CI, 1.97-212.22; P<0.01), positive histological margins (RR, 21.02; 95% CI, 5.51-80.26; P< 0.001), immunosuppression (RR, 17.97; 95% CI, 4.17-77.47; P <0.01) and duration of symptoms >75 days (RR, 10.13; 95% CI, 1.76-58.23; P =0.02) were associated with treatment failure. On multivariable analysis, positive margins (RR, 7.72; 95% CI, 2.71-22.01; P<0.001) and immunosuppression (RR, 6.45; 95% CI, 2.42-17.20; P =0.01) remained associated with treatment failure. Conclusions: Recurrence rates after exclusive surgical treatment of M. ulcerans disease in an Australian cohort are high, with increased rates associated with immunosuppression or positive histological margins.

On self-propagating methodological flaws in performance normalization for strength and power sports

Performance in strength and power sports is greatly affected by a variety of anthropometric factors. The goal of performance normalization is to factor out the effects of confounding factors and compute a canonical (normalized) performance measure from the observed absolute performance. Performance normalization is applied in the ranking of elite athletes, as well as in the early stages of youth talent selection. Consequently, it is crucial that the process is principled and fair. The corpus of previous work on this topic, which is significant, is uniform in the methodology adopted. Performance normalization is universally reduced to a regression task: the collected performance data are used to fit a regression function that is then used to scale future performances. The present article demonstrates that this approach is fundamentally flawed. It inherently creates a bias that unfairly penalizes athletes with certain allometric characteristics, and, by virtue of its adoption in the ranking and selection of elite athletes, propagates and strengthens this bias over time. The main flaws are shown to originate in the criteria for selecting the data used for regression, as well as in the manner in which the regression model is applied in normalization. This analysis brings into light the aforesaid methodological flaws and motivates further work on the development of principled methods, the foundations of which are also laid out in this work.