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While the analysis of gait and balance can be an important indicator of age- or disease-related changes, it remains unclear if repeated performance of gait and balance tests in healthy adults leads to habituation effects, if short-term gait and balance training can improve gait and balance performance, and whether the placement of wearable sensors influences the measurement accuracy. Healthy adults were assessed before and after performing weekly gait and balance tests over three weeks by using a force plate, motion capturing system and smartphone. The intervention group (n = 25) additionally received a home-based gait and balance training plan. Another sample of healthy adults (n = 32) was assessed once to analyze the impact of sensor placement (lower back vs. lower abdomen) on gait and balance analysis. Both the control and intervention group exhibited improvements in gait/stance. However, the trends over time were similar for both groups, suggesting that targeted training and repeated task performance equally contributed to the improvement of the measured variables. Since no significant differences were found in sensor placement, we suggest that a smartphone used as a wearable sensor could be worn both on the lower abdomen and the lower back in gait and balance analyses. [ABSTRACT FROM AUTHOR]

As commercial fishing activity shifts to target different grounds over time, spatial gaps can be created in catch rate data, leading to biases in derived indices of fish abundance. Imputation has been shown to reduce such biases. In this study, the relative performance of several imputation methods was assessed using simulated catch rate data sets. Simulations were carried out for three fish stocks targeted by a commercial hook-and-line fishery off the southwestern coast of Australia: snapper (Chrysophrys auratus), West Australian dhufish (Glaucosoma hebraicum), and baldchin groper (Choerodon rubescens). For high-growth scenarios, the mean squared errors (MSEs) of geometric and linear imputations were lower, indicating higher accuracy and precision than that for base method (constant value) imputations. For low-growth scenarios, the lowest MSEs were achieved for base method imputations. However, for the final standardized and imputed abundance indices, the base method index consistently demonstrated the largest biases. Our results demonstrate the importance of selecting an appropriate imputation method when standardizing catch rates from a commercial fishery that has changed its spatial pattern of fishing over time. Quand des activites de peche commerciale changent dans le temps pour cibler differents lieux de peche, des lacunes spatiales dans les donnees sur les taux de prises peuvent en resulter et mener a des biais dans les indices d'abondance de poissons en decoulant. Il a ete demontre que l'imputation reduit ce type de biais. Dans la presente etude, la performance relative de plusieurs methodes d'imputation a ete evaluee en utilisant des ensembles de donnees sur les taux de prises simules. Des simulations ont ete realisees pour trois stocks de poissons vises par une peche a la ligne au large de la cote sud -ouest de l'Australie, le vivaneau (Chrysophrys auratus), le merou geant (Glaucosoma hebraicum) et le labre (Choerodon rubescens). Pour les scenarios de forte croissance, les erreurs quadratiques moyennes (EQMs) des imputations geometriques et lineaires etaient plus faibles, indiquant de plus grandes exactitude et precision, que celles des imputations par la methode de base (valeur constante). Pour les scenarios de faible croissance, les EQM les plus faibles ont ete obtenues pour les imputations par la methode de base. Toutefois, pour les indices d'abondance normalisee et imputee finaux, l'indice de la methode de base etait uniformement caracterise par les plus grands biais. Les resultats demontrent l'importance du choix d'une methode d'imputation convenable pour la normalisation des taux de prises d'une peche commerciale dont la repartition spatiale a change au fil du temps. [Traduit par la Redaction], Introduction Conventional statistical methods, including generalized linear models (GLMs), are routinely used to standardize commercial catch per unit effort (CPUE) data into indices of relative fish abundance for stock assessment. [...]

Objectives: It is well known that there are associations between overall health, age, socioeconomic status and rural residency. The objective of this study was to determine the distribution of Australia's aged population by socioeconomic status, as well as remoteness. Methods: The study employed the Australian Statistical Geography Standard (Statistical Area Level 1 and Remoteness Areas). The database of the geographic boundaries was integrated into the ageing population and socioeconomic data using the Geographic Information System. The socioeconomic data was analysed through the Index of Relative Socioeconomic Disadvantage. Results: Over a decade, the older population in Australia has increased noticeably. In 2016, there was a high percentage of older people (≥65 years) in Tasmania (Tas), 19%, while the lowest percentage was recorded in the Northern Territory (NT), 7%. Across the country, Tasmania had the highest percentage of older citizens living in the most disadvantaged areas since 2006, with 48% recorded in 2016. There was an association between the remoteness areas and the education and income levels of the ageing cohort. However, this association differed between the states and territories. This socioeconomic gap becomes more evident in the very remote areas of the country. Conclusions: The ageing population in Australia is increasing rapidly; this was associated with an evolving socioeconomic disparity among this ageing society. Our results demonstrated that socioeconomic inequalities were to be found among the older people based on their distribution over the remoteness areas in Australia. This information should be used to target healthcare and ageing policies that meet the specific needs of older people. [ABSTRACT FROM AUTHOR]

Misallocation of finite healthcare resources can occur when guided by maps that are produced using aggregate-level administrative units. Such maps are affected by the modifiable areal unit problem (MAUP), which describes how patterns may change depending on the particular choice of mapping unit. Smoothing can help avoid this unintended yet detrimental phenomenon. This paper compares the utility of aggregate-level administrative units and smoothing for exploring variation in lower urgency emergency department (ED) presentations across metropolitan Perth, Western Australia. Rates of such presentations were mapped using Australian Bureau of Statistics Statistical Areas Levels 1, 2, and 3 (SA1-3s) and the recently proposed Overlay Aggregation Method (OAM). Resulting maps were compared based on their ability to represent local variation in rates and optimise the targeting and logistical efficiency of geographically targeted resource allocation. SA1-level variation in rates was increasingly obscured by SA2s and SA3s. OAM helped avoid this pitfall, facilitating stable identification of SA1-resolution, high-rate regions while preserving privacy, mitigating the MAUP, and balancing the targeting and logistical efficiency of planned resource allocation to those regions. Routine application of smoothing can help avoid issues undermining maps of lower urgency ED presentations and other health outcomes that are based on aggregate-level administrative units. [ABSTRACT FROM AUTHOR]

Precise population counts facilitate reliable estimation of differences in disease risk between population sub-groups or geographic regions, which informs rational public health decision-making. In Australia, Census population counts obtainable via the Australian Bureau of Statistics' (ABS') TableBuilder tool, which are widely used, are routinely perturbed to protect privacy. We examine this perturbation's impact on: the precision of TableBuilder population counts, and a geospatial analysis of high-risk foot (HRF) hospital admissions among Western Australian (WA) Indigenous people. The former is severely compromised, disproportionately so for Indigenous people and under the currently employed 'perturbation without additivity' (PWoA) approach. E.g., based on fine-resolution, PWoA-affected data, the Indigenous population total for 'Inner City' WA was >50% lower than its true total. Imprecise calculation of WA Indigenous HRF admission counts, and misrepresentation of high-rate regions of such admissions in Perth, resulted. An approach suggested to manage this - examination of coarse-resolution data - is inadequate, partly due the modifiable areal unit problem. However, a novel map overlay technique alleviates this issue. We recommend that the ABS review the PWoA approach and consider implementing different statistical disclosure control techniques or reverting to the previously employed 'perturbation with additivity' approach, prior to releasing data from the 2021 Australian Census. [ABSTRACT FROM AUTHOR]

Objective: To examine the impact of the modifiable areal unit problem (MAUP) in an investigation of factors associated with ED demand in Perth, Western Australia, in 2016. Furthermore, to advocate a means of avoiding this impact. Methods: ED presentations were classified as: urgent medical, non‐urgent medical, urgent trauma or non‐urgent trauma. In each group, sex‐stratified, age‐adjusted multivariate associations with socio‐economic status and distance to the nearest ED and general practitioner (GP) were estimated. Modelling was undertaken using different sets of spatial units: Australian Bureau of Statistics (ABS) Statistical Areas Level 1 (SA1s) and numerous aggregate‐level zonations of SA1s (ABS SA2s and others). Results: Estimates obtained using the different units often varied widely: for seven (30%) of 24 strata defined by combinations of sex, ED type and covariate, the smallest and largest effect sizes differed in terms of direction; further, for 11 (65%) of the remaining 17 strata, the largest effect size was at least twice as high as the smallest. This demonstrates the MAUP's impact and that analyses based on a single set of spatial units are unreliable. To resolve the observed variation, we highlight the SA1‐level estimates. Conclusions: When formulating interventions targeting reduced ED utilisation, policy planners should be guided by evidence based on analysis of appropriate spatial units. This ideal is undermined by the widespread lack of acknowledgement of the MAUP in studies examining drivers of ED demand using spatially aggregated data. To avoid the MAUP, only estimates obtained through examining a minimal geographic unit should be relied upon. [ABSTRACT FROM AUTHOR]

To identify changes in orthodontic management strategies in patients with hypodontia seen in 2000, 2010, and 2017/2018 (during a 1-year period). An assessment of the panoramic radiographs of 3701 patients from a Western Australian private practice identified 276 individuals demonstrating hypodontia. The location of missing teeth, age, sex, type of malocclusion, and the management strategies (space closure or opening) for each patient were noted. Most hypodontia involved agenesis of three or fewer teeth (90%). Maxillary lateral incisors and mandibular second premolars were the most commonly missing teeth. Female preponderance was noted. When considering treatment, the odds ratio for orthodontic space opening and prosthetic replacement in 2000 was 3.266 (P value = 7e-04; 95% confidence interval [CI], 1.464–4.633) compared with patients seen in 2010 and 1.632 (P value = 7e-04; 95% CI, 0.811–2.434) compared with patients in 2017/2018. For patients demonstrating bilateral absence of maxillary lateral incisors, the odds ratio for orthodontic space opening was 3.185 (P value = 0.0215; 95% CI, 1.182–9.243) compared with counterparts with unilateral agenesis. None of the factors investigated were significantly associated with the types of treatment planned/provided for the patients with missing mandibular second premolars. Maxillary lateral incisors and mandibular second premolars were the most commonly missing teeth. A trend away from space opening and prosthetic replacement toward orthodontic space closure was observed from 2000 to 2017/2018. This may reflect a change in attitude toward prosthetic replacement options and/or greater optimism with biomechanical strategies since the implementation of temporary anchorage devices to assist in space closure. [ABSTRACT FROM AUTHOR]

Summary: Accelerometry is a low‐cost and noninvasive method that has been used to discriminate sleep from wake, however, its utility to detect sleep stages is unclear. We detail the development and comparison of methods which utilise raw, triaxial accelerometry data to classify varying stages of sleep, ranging from sleep/wake detection to discriminating rapid eye movement sleep, stage one sleep, stage two sleep, deep sleep and wake. First‐ and second‐order hidden Markov models (HMMs) with time‐homogeneous and time‐varying transition probability matrices, along with continuous acceleration observations in the form of a Gaussian‐observation HMM and K‐means classified acceleration in a discrete‐observation HMM were explored. In addition, generalised linear mixed models (GLMMs) with binary and multinomial responses and logit link functions were considered as was whether incorporating adjoining acceleration information into the models improved prediction. Model predictions were compared to the reference‐standard in sleep detection (polysomnography) and outcome accuracies were calculated. Consistently, HMMs yielded greater sleep stage detection than GLMMs but there was little difference between first‐ and second‐order HMMs. Varying degrees of difference were observed when comparing Gaussian‐observation HMMs to discrete‐observation HMMs, and time‐varying HMMs yielded greater discrimination than time‐homogeneous HMMs, as did models which considered adjoining acceleration information. These results suggest that wrist‐worn accelerometry data may be able to detect sleep stages but that further investigation is required to optimise classification accuracy. Development and comparison of hidden Markov models and generalized linear mixed models which use raw, triaxial wrist accelerometry data to determine sleep stages. [ABSTRACT FROM AUTHOR]

This article explores an ‘Edge Selection’ procedure to fit an undirected graph to a given data set. Undirected graphs are routinely used to represent, model and analyse associative relationships among the entities on a social, biological or genetic network. Our proposed method combines the computational efficiency of least angle regression and at the same time ensures symmetry of the selected adjacency matrix. Various local and global properties of the edge selection path are explored analytically. In particular, a suitable parameter that controls the amount of shrinkage is identified and we consider several cross-validation techniques to choose an accurate predictive model on the path. The proposed method is illustrated with a detailed simulation study involving models with various levels of sparsity and variability in the nodal degree distributions. Finally, our method is used to select undirected graphs from various real data sets. We employ it for identifying the regulatory network of isoprenoid pathways from a gene-expression data and also to identify genetic network from a high-dimensional breast cancer study data. [ABSTRACT FROM AUTHOR]

Optimization problems in which a quadratic objective function is optimized subject to linear constraints on the parameters are known as quadratic programming problems ( QPs). This focus article reviews algorithms for convex QPs (in which the objective is a convex function) and provides pointers to various online resources about QPs. WIREs Comput Stat 2015, 7:153-159. doi: 10.1002/wics.1344 For further resources related to this article, please visit the . Conflict of interest: The authors have declared no conflicts of interest for this article. [ABSTRACT FROM AUTHOR]

In robotic vision using laser-radar measurements, noisy data on convex sets with corners are derived in terms of the set's support function. The corners represent abutting edges of manufactured items, and convey important information about the items' shape. However, simple methods for set estimation, for example based on fitting random polygons or smooth sets, either add additional corners as an artifact of the algorithm, or approximate corners by smooth curves. It might be argued, however, that corners have special significance in the interpretation of a set, and should not be introduced as an artifact of the estimation procedure. In this paper we suggest a corner-diagnostic approach, in the form of a three-step algorithm which (a) identifies the number and positions of corners, (b) fits smooth curves between corners, and (c) splices together the smooth curves and the corners, to produce an over-all estimate of the convex set. The corner-finding step is parametric in character, and although it is based on detecting change points in high-order derivatives of the support function, it produces root-n consistent estimators of the locations of corners. On the other hand, the smooth-curve fitting step is entirely nonparametric. The splicing step marries these two disparate approaches into a single, practical method. Index Terms - Circular data, diagnostic, kernel, laser radar, robotic vision, smoothing parameter, spline, support function.

Background: Although rapid diagnostic tests (RDTs) have practical advantages over light microscopy (LM) and good sensitivity in severe falciparum malaria in Africa, their utility where severe non-falciparum malaria occurs is unknown. LM, RDTs and polymerase chain reaction (PCR)-based methods have limitations, and thus conventional comparative malaria diagnostic studies employ imperfect gold standards. We assessed whether, using Bayesian latent class models (LCMs) which do not require a reference method, RDTs could safely direct initial anti-infective therapy in severe ill children from an area of hyperendemic transmission of both Plasmodium falciparum and P. vivax. Methods and Findings:We studied 797 Papua New Guinean children hospitalized with well-characterized severe illness for whom LM, RDT and nested PCR (nPCR) results were available. For any severe malaria, the estimated prevalence was 47.5% with RDTs exhibiting similar sensitivity and negative predictive value (NPV) to nPCR ($96.0%). LM was the least sensitive test (87.4%) and had the lowest NPV (89.7%), but had the highest specificity (99.1%) and positive predictive value (98.9%). For severe falciparum malaria (prevalence 42.9%), the findings were similar. For non-falciparum severe malaria (prevalence 6.9%), no test had the WHO-recommended sensitivity and specificity of .95% and .90%, respectively. RDTs were the least sensitive (69.6%) and had the lowest NPV (96.7%). Conclusions: RDTs appear a valuable point-of-care test that is at least equivalent to LM in diagnosing severe falciparum malaria in this epidemiologic situation. None of the tests had the required sensitivity/specificity for severe non-falciparum malaria but the number of false-negative RDTs in this group was small. [ABSTRACT FROM AUTHOR]