Clair L. Alston-Knox

• Doctor of Philosophy
• Statistician at Predictive Analytics Group

The experiment evaluated a method for statistically assessing the accuracy of technologies that measure intramuscular fat percentage (IMF%), enabling referencing against accreditation accuracy thresholds. To compare this method to the existing rules-based industry standard we simulated data for 4 separate devices that predicted IMF% across a range...

It is widely acknowledged that tourists are particularly likely to be victimized, especially with regard to property crimes like theft from tourist accommodation (burglary). Guided by the criminal opportunity perspective, we examine the extent to which environmental and routine activities-related factors explain burglary using the data from a sampl...

Lamb growth can be optimised with genetic selection using sire Australian sheep breeding values, however, breeding value expression has been shown to be reduced with poor nutrition. It was therefore hypothesised that the genetic potential for lamb growth would also be reduced, where production factors such as multiple births limit growth. Live weig...

This study examines the effect of online lifestyles and routine activities on self-guardianship against cyber abuse. The data from a sample of U.S. adults (N = 746) was modelled using a binary logistic regression and Bayesian variable selection with the stochastic search algorithm. We found that, on average, victims who employ self-guardianship ten...

Like other low-income countries in Asia and Africa, Nepal still suffers from food insecurity with a large proportion of food-insecure households being smallholder farmers who rely on rain-fed agriculture for their livelihood. Contributing factors include a lack of production, lack of resources, access to land and market, climate change, extreme eve...

The ever-increasing use of telecommunication technologies and the Internet have led to an increase in new technology-facilitated types of crime and deviance. Due to the challenges posed by the unique environment of cyberspace on the formal crime control agents (e.g., the police), the role of informal guardians becomes particularly salient. The rece...

Evidence-based practices for classroom management are well established and predominantly preventative in nature. However, use of reactive practices by teachers has been widely reported internationally, particularly in middle and high school settings. Teachers (N = 587) throughout government high schools in Queensland, Australia responded to a surve...

Objectives: Forensic anthropologists assign biological profiles (ancestry, biological sex, age and stature) to skeletal remains to assist with the human identification process. The humerus can be used for the assessment of biological sex and subsequently for stature. Materials and Methods: Post-mortem computed tomography (PMCT) post-cranial samp...

Crime and deviance can have a significant and long-lasting effect on victims. While the literature on victim impact from traditional types of crime like robbery or assault is well established, much smaller scholarship examines the impact of online forms of deviance with only a handful of studies focusing on the experiences of adult victims. The cur...

Objectives: In rugby union scrummaging, front-row players often sustain lumbar spine injuries, which can lead to physical impairments and absence from play. Poor lumbar spine posture adopted by front-row players during scrummaging may contribute to these lumbar spine injuries. However, few studies have investigated lumbar spine kinematics in front-...

This paper presents the findings from a mixed-methods examination of self-protective behaviours (SPBs) adopted by victims of cyber abuse from the rational choice perspective. The data from a sample of the U.S. adults (N=746), members of an online opt-in panel, were analysed to first distinguish the types of SPBs adopted by victims of cyber abuse us...

A preventative approach to classroom management is associated with increases in student engagement and improved teacher well-being. However, research indicates that many teachers use predominantly reactive practices, aimed at controlling student behaviour. Queensland state secondary school teachers (N = 587) were surveyed about the classroom manage...

Purpose This study aims to explore and develop new theories. These theories emerged from combining environmental psychology literature with sustainability literature and the five research questions at the core of the work built upon a central theme of sustainability that argues us and the organizations require a relationship of entwinement rather t...

The aim of this study is to quantify and statistically model the age‐related decline in the fibrous connective tissue interface of the anterior fontanelle in modern Australian infants, using three‐dimensional, semi‐automated computed‐assisted design protocols. Non‐linear regression with variance models, using power functions, combined with quantile...

Crime can have a significant and long-lasting effect on its victims. While the literature on victim impact from traditional types of crime like robbery or assault is well established, little of the published research examining the impact of online crime like cyber abuse. The current paper examines victim impact and self-protective behaviours follow...

Background: The emergence of new technology-facilitated types of crime following the advent of the Internet necessitated the re-examination of the utility of traditional theories such as lifestyle-routine activity theory to explain crimes that occur in the new and unique environment of cyberspace. Reason for study: The objective of this study was...

The reproducibility crisis in science has launched global discussion about the need to restructure the way statistics is taught across a wide range of disciplines. While this need has been recognized and discussed in the academic community for many years, the impetus for educational reform of statistics was boosted by Ioannidis (2005), which result...

The aim of this study was to identify sensory subtypes in children on the autism spectrum using the Short Sensory Profile-2 (SSP-2). Caregivers of children on the autism spectrum aged 4-11 years (n = 271) completed the SSP-2. Analysis using Dirichlet process mixture model identified a two-cluster model which provided the best solution to subtype se...

An evaluation of the development of a child’s skeleton and estimation of bone age provides an insight into a child’s overall maturation. This study aimed to introduce a contemporary method for assessing bone age of Australian children using formulae incorporating carpal areal measurements. The standards introduced in this study can be used to asses...

The aim of this study was to compare cervical spine kinematics in rugby union front row players during machine-based and “live” scrummaging. Cervical spine kinematics was measured via electromagnetic tracking of sensors attached to the head and thorax. Joint angles were extracted from each trial at two time points (“bind” prior to engagement and in...

The aim of this study was to identify sensory subtypes in children on the autism spectrum using the Short Sensory Profile-2 (SSP-2). Caregivers of children on the autism spectrum aged 4 – 11 years (n = 271) completed the SSP-2. Analysis using Dirichlet process mixture model identified a two-cluster model which provided the best solution to subtype...

Diet quality influences glycemic control in people with type 2 diabetes (T2D), impacting their risk of complications. While there are many cross-sectional studies of diet and diabetes, there is little understanding of the extent to which people with T2D change their diet after diagnosis and of the factors that impact those changes. This paper descr...

In the context of generalized linear models (GLMs), interactions are automatically induced on the natural scale of the data. The conventional approach to measuring effects in GLMs based on significance testing (e.g. the Wald test or using deviance to assess model fit) is not always appropriate. The objective of this paper is to demonstrate the limi...

Interview schedule. (DOCX)

Background: It is well documented that mothers of children with intellectual disabilities or autism experience elevated stress, with mental health compromised. However, comparatively little is known about mothers of children with rare genetic syndromes. This study describes mental health and well-being in mothers of children with 13 rare genetic sy...

Background Adherence to treatment is a primary determinant of treatment success. Caregiver support can influence medication adherence in people with cognitive impairment. This study sought to characterize medication adherence in older people with dementia from the caregivers’ perspective, and to identify influencing factors. Methods Caregivers car...

This paper presents a Bayesian mixture model approach for detecting areas of habitat that are suitable for S. invicta infestation, aiding the ongoing surveillance for early detection of these exotic pests. We show that Landsat imagery is an affordable and valuable tool to assist in determining an informed surveillance strategy. In this paper, we us...

Background D‐Cycloserine has potential to enhance exposure therapy outcomes. The current study presents a preliminary randomized, placebo‐controlled double‐blind pilot trial of DCS‐augmented one‐session treatment (OST) for youth (7–14 years) with specific phobia. A secondary aim of this pilot study was to explore the effects of youth age and within...

Despite the recognized flaws in applying traditional stature estimation equations such as those of Trotter and Gleser (1952) to a contemporary population, there are currently no available alternatives for stature estimation in Australia that address these limitations. Post mortem computed tomography (PMCT) DICOM scans of the left and right femora w...

Cyber abuse can be executed directly (e.g. by sending derogatory emails or text messages addressed to the victim) or indirectly (e.g. by posting derogatory, private or false information, documents, images or videos about the victim online). This exploratory, mixed-method, triangulated study examines cyber abuse crime events with the goal of identif...

Bayesian methods provide a more general approach to statistical analysis that mathematically includes Null Hypothesis Significance Testing (NHST) and classical statistical modelling as special cases. This expanded, Bayesian, approach provides several benefits, which we illustrate using a case study about decision-making by teachers. We focus on a r...

Background: Children on the autism spectrum participate less frequently, and in a narrower range of activities, than their nonautistic peers, but little is known about exact participation patterns across contexts or how this is perceived by caregivers. This study aimed to document patterns of participation and caregiver views with regard to freque...

Background Cognitive‐behavioural therapy (CBT) is an efficacious treatment for anxiety disorders in children and adolescents, yet not all young people improve. Understanding predictors of treatment response can inform treatment improvements in order to enhance outcomes. Aim The purpose of this study was to compare treatment outcomes following grou...

This study contrasts the ontogeny of the iliac crest apophysis using conventional radiography and multislice computed tomography (MSCT), providing probabilistic information for age estimation of modern Australian subadults. Retrospective abdominopelvic MSCT data acquired from 524 Australian individuals aged 7–25 and surveillance radiographs of adol...

Contemporary, population-specific ossification timings of the cranium are lacking in current literature due to challenges in obtaining large repositories of documented subadult material, forcing Australian practitioners to rely on North American, arguably antiquated reference standards for age estimation. This study assessed the temporal pattern of...

From remote sensing of the environment, to brain scans in medicine, the growth in the use of image data has motivated a parallel increase in statistical techniques for analysing these images. A particular area of growth has been in Bayesian models and corresponding computational methods. Bayesian approaches have been proposed to address the gamut o...

A new transdimensional Sequential Monte Carlo (SMC) algorithm called SMCVB is proposed. In an SMC approach, a weighted sample of particles is generated from a sequence of probability distributions which ‘converge’ to the target distribution of interest, in this case a Bayesian posterior distribution. The approach is based on the use of variational...

After attending this presentation, attendees will appreciate the advantages and principal processes of applying a semi-automated growth plate measurement protocol based on voxelization and volume calculation to quantify the tissue composition of irregular skeletal regions such as the spheno-occipital synchondrosis. This presentation will impact th...

Due to disparity regarding the age at which skeletal maturation of the spheno-occipital synchondrosis occurs in forensic and biological literature, this study provides recalibrated multislice computed tomography (MSCT) age standards for the Australian (Queensland) population, using a Bayesian statistical approach. The sample comprises retrospective...

In 2001, the red imported fire ant (Solenopsis invicta Buren) was identified in Brisbane, Australia. An eradication program involving broadcast bait treatment with two insect growth regulators and a metabolic inhibitor began in September of that year and is currently ongoing. To gauge the impacts of these treatments on local ant populations, we exa...

The issue of using informative priors for estimation of mixtures at multiple time points is examined. Several different informative priors and an independent prior are compared using samples of actual and simulated aerosol particle size distribution (PSD) data. Measurements of aerosol PSDs refer to the concentration of aerosol particles in terms of...

Massive datasets are increasingly encountered in modern research applications, and this presents tremendous new challenges for statisticians. In settings where the aim is to classify or cluster data via finite mixture modelling, such as in satellite image analysis, the large number data points to be analysed can make fitting such models either infe...

Despite the prominent use of the Suchey-Brooks (S-B) method of age estimation in forensic anthropological practice, it is subject to intrinsic limitations, with reports of differential interpopulation error rates between geographical locations. This study assessed the accuracy of the S-B method to a contemporary adult population in Queensland, Aust...

Provides an accessible foundation to Bayesian analysis using real world models This book aims to present an introduction to Bayesian modelling and computation, by considering real case studies drawn from diverse fields spanning ecology, health, genetics and finance. Each chapter comprises a description of the problem, the corresponding model, the c...

Introduction Case study Review Case study modelling Model implementation: Coding considerations Case study results Conclusions References

Introduction Case study: CT scan images of sheep Models and methods Data analysis and results Discussion References

Introduction Bayesian analysis Empirical illustrations Using PyMCMC efficiently PyMCMC interacting with R Conclusions Obtaining PyMCMC References

In this paper, we describe an analysis for data collected on a three-dimensional spatial lattice with treatments applied at the horizontal lattice points. Spatial correlation is accounted for using a conditional autoregressive model. Observations are defined as neighbours only if they are at the same depth. This allows the corresponding variance co...

Modern technology now has the ability to generate large datasets over space and time. Such data typically exhibit high autocorrelations over all dimensions. The field trial data motivating the methods of this paper were collected to examine the behaviour of traditional cropping and to determine a cropping system which could maximise water use for g...

Conservation planning and management programs typically assume relatively homogeneous ecological landscapes. Such “ecoregions” serve multiple purposes: they support assessments of competing environmental values, reveal priorities for allocating scarce resources, and guide effective on-ground actions such as the acquisition of a protected area and h...

IntroductionMixture modelsAltering dimensions of the mixture modelBayesian mixture model incorporating spatial informationVolume calculationDiscussionReferences

In this paper, we examine approaches to estimate a Bayesian mixture model at both single and multiple time points for a sample of actual and simulated aerosol particle size distribution (PSD) data. For estimation of a mixture model at a single time point, we use Reversible Jump Markov Chain Monte Carlo (RJMCMC) to estimate mixture model parameters...

The usual Gibbs sampling framework of the Bayesian mixture model is extended to account for binned data. This model involves the addition of a latent variable in the model which represents simulated values from the believed true distribution at each iteration of the algorithm. The technique results in better model fit and recognition of the more su...

Weed-detecting reflectance sensors were modified to allow selective interrogation of the near infrared-red ratio to estimate differences in plant biomass. Sampling was programmed to correspond to the forward movement of the field of view of the sensors. There was a linear relationship (r(2) > 0.80) between actual biomass and crop canopy analyzer (C...

Interest in the use of computed tomography (CT) scanning in animal experimentation has increased markedly over the last decade due to the benefits of studying tissue in live subjects over time. In these experiments, the non-carcass components of the scan are removed from the collected data, allowing scientists to study the carcass of a live animal...

CAT scanning is used in longitudinal animal science experiments to assess possible changes to carcase composition induced by treatment over given time periods. A hierarchical Bayesian mixture model can be used to analyse the CAT scan data in terms of the proportion of each tissue type present in a scan. In this paper we present an extension to the...

The organic carbon stock in biomass and soil profiles sampled from nearby paddocks with different land-use histories was estimated at 7 sites in the upper Liverpool Plains catchment and the Manilla district of north-western New South Wales, Australia. The distribution of soil carbon concentrations over a depth of 2 m was significantly affected by s...

This paper provides a brief review of the more popular methods for comparing models in a Bayesian framework. Personal experience in implementing these methods in problems requiring mixture models is also referenced.

The purpose of CAT scanning in some animal science experiments is to provide estimates of the proportion of the tissues, fat, muscle, and bone present in an individual body, and compare some of the density characteristics. In this paper we present an extension to the hierarchical Bayesian Normal mixture model, which incorporates some of the informa...

Bayesian Belief Networks (BBNs) are emerging as valuable tools for investigating complex ecological problems. In a BBN, the important variables in a problem are identified and causal relationships are represented graphically. Underpinning this is the probabilistic framework in which variables can take on a finite range of mutually exclusive states....

CAT scanning techniques are available to provide images that can aid in the assessment of carcass traits in live sheep during the course of animal experiments. In this paper we present a Bayesian formulation of an analysis that allows us to determine the composition of a scan in terms of proportions of the image attributable to fat, muscle (lean ti...

This study investigated effects of birth weight and postnatal nutrition on regulation of energy metabolism in the neonatal lamb. Low (mean ± SD 2.289 ± 0.341 kg, n = 28) and high (4.840 ± 0.446 kg, n = 20) birth weight male Suffolk × (Finnsheep × Dorset) lambs were individually reared on a liquid diet to grow rapidly (ad libitum fed, ADG = 337 g, n...

Three field experiments using grain sorghum (Sorghum bicolor), an important dryland summer crop on the Liverpool Plains in northern New South Wales, were conducted: (i) to determine the effect of dryland salinity on the yield of commercial crops at 2 sites; (ii) to see if ridging the soil would ameliorate the problem; and (iii) to compare 16 commer...

Weed sampling can be a time consuming and repetitive task if populations are to be adequately monitored. In situations where there are a range of species densities, high numbers of samples are required, and/or where the sample area is large, it may be appropriate to group weed densities into ordinal categories. An ordinal system is outlined in whic...

Three field experiments using grain sorghum (Sorghum bicolor), an important dryland summer crop on the Liverpool Plains in northern New South Wales, were conducted: (i) to determine the effect of dryland salinity on the yield of commercial crops at 2 sites; (ii) to see if ridging the soil would ameliorate the problem; and (iii) to compare 16 commer...

The light-textured, red, gradational and duplex soils in semi-arid central western New South Wales were found to be on a pH threshold for suitability for the traditional cultivars of barrel medic (Medicago truncatula), an important pasture legume in the region, and other acid sensitive species. However, there was little evidence that cropping over...

The use of nitrogen fertilisers to arrest the decline in soil nitrogen fertility in the northern grains belt of New South Wales has been the subject of many years of research, however, little is known about how farmers make decisions about nitrogen fertiliser. A survey of 400 wheat farmers in northern New South Wales in April 1997 revealed that man...

Rotational effects of chickpea, an important N2-fixing pulse legume of the northern grains region, on subsequent wheat require quantification of the contribution of the legume to soil N and the N status of the wheat, and of suppression of soil and stubble-borne pathogens, such as crown rot (Fusarium graminearum Schwabe Group 1). Results from select...

Increased accuracy of estimating maintenance requirements of both mature and immature animals can be achieved by adjusting the estimate for changes in energy resulting from either tissue accretion or mobilisation that occur during the test period. The present study examined changes in maintenance requirements over time within individual mature shee...

Field experiments are often affected by both spatial and temporal (i.e. repeated measures) correlation. In order to obtain an analysis that is scientifically valid it is important to recognise the underlying error structure and analyse the data accordingly. We will discuss the analysis of count data which is spatially and temporally correlated, and...

Information on farm work-related injuries was sought to assist in the design of effective farm safety prevention programs. A telephone survey was conducted using a stratified random sample of 919 sheep/wool, beef cattle and dryland broadacre cropping farms from three shires in the wheat/sheep belt of New South Wales. The adjusted response rate was...