A. Jonathan R. Godfrey

Elevational variation in adult body size and growth rate but not in metabolic rate in the tree weta Hemideina crassidens.

Populations of the same species inhabiting distinct localities experience different ecological and climatic pressures that might result in differentiation in traits, particularly those related to temperature. We compared metabolic rate (and its thermal sensitivity), growth rate, and body size among nine high- and low-elevation populations of the Wellington tree weta, Hemideina crassidens, distributed from 9 to 1171 m a.s.l across New Zealand. Our results did not indicate elevational compensation in metabolic rates (metabolic cold adaptation). Cold acclimation decreased metabolic rate compared to warm-acclimated individuals from both high- and low-elevation populations. However, we did find countergradient variation in growth rates, with individuals from high-elevation populations growing faster and to a larger final size than individuals from low-elevation populations. Females grew faster to a larger size than males, although as adults their metabolic rates did not differ significantly. The combined physiological and morphological data suggest that high-elevation individuals grow quickly and achieve larger size while maintaining metabolic rates at levels not significantly different from low-elevation individuals. Thus, morphological differentiation among tree weta populations, in concert with genetic variation, might provide the material required for adaptation to changing conditions.

Producing Accessible Statistics Diagrams in R

Blind people are at risk of being left behind in the information age if efforts are not made to improve the access to information that is not traditionally conveyed in text, whether that text be accessed in braille, audio, or a computers screen reading software. Most graphics summarise a scene or some aspect of data that the author hopes will inform their audience; good statistical graphics are commonly used to great effect for the sighted world, but are practically useless to a blind audience. Our work aims to provide an accessible way for blind users to easily, efficiently, and most importantly accurately, explore and query the data contained in diagrams such as bar charts, box plots, time series, and many more. We employ the statistical software environment R to compute rich semantics for these diagrams and make them web accessible by supporting screen reading and interactive exploration.

Monitoring acute and chronic kidney failure using statistical process control techniques

ABSTRACT Creatinine tests are used to determine a patients estimated glomerular filtration rate (eGFR) for the assessment of kidney function. This article describes how eGFR results for patients who need to have their cases referred for the attention of a specialist can be filtered out from among the numerous patients whose test results indicate that they are either displaying no reduction in kidney function or whose kidney function is reduced but remains stable. Automation of the process is a key ingredient of our solution because this is the means by which the human effort is directed to those patients in greatest need.

Advice From Blind Teachers on How to Teach Statistics to Blind Students

Blind students are bound to make up a very small part of the population most university lecturers will encounter during their careers. Research to date shows that good communication between staff and student improves the chances of a successful outcome for both parties. The research does show, however, that the exercise seems to be one of re-inventing the wheel, perhaps with a less than fully informed blueprint to work from. The authors use their own experiences as blind students who progressed beyond research methods or first year introductory courses into careers as teachers and researchers of statistical methods to provide guidance for their sighted colleagues. Our principle point of difference to the existing research work is that we rely on the experience of our statistical education for our current livelihoods; we were not one-off students taking a research methodology course or first year introductory course. We benefitted from the successful (and possibly the not so successful) interactions we had with our sighted teachers. It is our hope that by saving staff from wasted effort, we can spare students from unnecessary discomfort in classes that could improve their future employment prospects. Our aim is therefore to provide practical support for our sighted colleagues and blind peers as we work together towards the empowerment of blind students in becoming competent producers of statistical information, not just consumers who interpret that information.

Decomposition of stock market trade-offs using Shewhart methodology

Purpose The purpose of this paper is to investigate the applicability of Shewhart methodology and other quality management principles to gain a deeper understanding of the observed volatility in stock returns and its impact on market performance. Design/methodology/approach The validity of quality management philosophy in the context of financial market behaviour is discussed. The technique of rational subgrouping is used to identify the observable variations in stock returns as either common or special cause variation. The usefulness of the proposed methodology is investigated through empirical data. The risk/return and skewness/kurtosis trade-offs of S&P 500 stocks are examined. The consistency of this approach is reviewed by relating the separated variability to “efficient market” and “behavioural finance” theories. Findings Significant positive and negative risk/return trade-offs were found after partitioning the returns series into common and special cause periods, respectively, while total data did not exhibit a significant risk/return trade-off at all. A highly negative skewness/kurtosis trade-off was found in total and special cause periods as compared to the common cause periods. These results are broadly consistent with the theoretical concepts of finance and other empirical findings. Practical implications The quality management principles-based approach to analysing financial data avoids the complexities commonly found in stochastic-volatility forecasting models. Social implications The results provide new insights into the impact of volatility in stock returns. They should have direct implications for financial market participants. Originality/value The authors explore the relevance of Shewhart methodology in analysing variability in stock returns through reviewing financial market behaviour.

An Accessible Interaction Model for Data Visualisation in Statistics

Data is everywhere and its communication and understanding is an important pre-requisite for the full participation of individuals in the information age. Good data visualisation is commonly used to great effect for the sighted world, but are practically useless to a blind audience. Blind people are at risk of being left behind if efforts are not made to improve the access to information that is not traditionally conveyed in text, whether that text be accessed in braille, audio, or a computer’s screen reading software. Our work aims to provide an accessible way for blind users to easily, efficiently, and most importantly accurately, explore and query the data contained in diagrams such as bar charts, box plots, time series, and many more. We employ the statistical software environment R not only as a means to generate accessible diagrams, but also as a way for blind users to directly interact with data in the same way as their sighted peers by supporting immediate data visualisation via screen reading and interactive exploration.

Emergency Department Length of Stay for Maori and European Patients in New Zealand

Introduction Emergency department length of stay (ED LOS) is currently used in Australasia as a quality measure. In our ED, Maori, the indigenous people of New Zealand, have a shorter ED LOS than European patients. This is despite Maori having poorer health outcomes overall. This study sought to determine drivers of LOS in our provincial New Zealand ED, particularly looking at ethnicity as a determining factor. Methods This was a retrospective cohort study that reviewed 80,714 electronic medical records of ED patients from December 1, 2012, to December 1, 2014. Univariate and multivariate analyses were carried out on raw data, and we used a complex regression analysis to develop a predictive model of ED LOS. Potential covariates were patient factors, temporal factors, clinical factors, and workload variables (volume and acuity of patients three hours prior to and two hours after presentation by a baseline patient). The analysis was performed using R studio 0.99.467. Results Ethnicity dropped out in the stepwise regression procedure; after adjusting for other factors, a specific ethnicity effect was not informative. Maori were, on average, younger, less likely to receive bloodwork and radiographs, less likely to go to our observation area, less likely to have a general practitioner, and more likely to be discharged and to self-discharge; all of these factors decreased their length of stay. Conclusion Length of stay in our ED does not seem to be related to ethnicity alone. Patient factors had only a small impact on ED LOS, while clinical factors, temporal factors, and workload variables had much greater influence.