On estimating the variance of maximum entropy median for odd sample size
- Authors: Bani-Mustafa, Ahmed , Al-Nasser, Amjad D.
- Date: 2008
- Type: Text , Journal article
- Relation: Pakistan Journal of Statistics Vol. 24, no. 1 (2008), p. 1-10
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- Description: The estimation of Maximum Entropy (ME) median variance based on odd samples is discussed. The estimated variance is given in a form that depends on an incomplete beta function. We show that the ME-median is more efficient than the sample median for small samples.
- Description: C1
Y chromosome haplogroup as a novel biological risk factor for coronary artery disease - The results of tracking paternal lineages in the west of Scotland primary prevention study (WOSCOPS)
- Authors: Charchar, Fadi , Tomaszewski, Maciej , Barnes, Timothy , Wang, Y. , Brouilette, S. W. , Codd, Veryan , Bani-Mustafa, Ahmed , Padmanabhan, Sandosh , Dominiczak, Anna , Ford, I. , Samani, Nilesh
- Date: 2009
- Type: Text , Conference paper
- Relation: , p. S448-S448
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Robust extreme ranked set sampling
- Authors: Al-Nasser, Amjad D. , Bani-Mustafa, Ahmed
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Statistical Computation & Simulation Vol. 79, no. 7 (2009), p. 859-867
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- Description: In this paper, a robust extreme ranked set sampling (RERSS) procedure for estimating the population mean is introduced. It is shown that the proposed method gives an unbiased estimator with smaller variance, provided the underlying distribution is symmetric. However, for asymmetric distributions a weighted mean is given, where the optimal weights are computed by using Shannon's entropy. The performance of the population mean estimator is discussed along with its properties. Monte Carlo simulations are used to demonstrate the performance of the RERSS estimator relative to the simple random sample (SRS), ranked set sampling (RSS) and extreme ranked set sampling (ERSS) estimators. The results indicate that the proposed estimator is more efficient than the estimators based on the traditional sampling methods. [ABSTRACT FROM AUTHOR]
Inheritance of coronary artery disease in men : An analysis of the role of the y chromosome
- Authors: Charchar, Fadi , Bloomer, Lisa , Barnes, Timothy , Cowley, Mark , Nelson, Christopher , Wang, Yanzhong , Denniff, Matthew , Debiec, Radoslaw , Christofidou, Paraskevi , Nankervis, Scott , Dominiczak, Anna , Bani-Mustafa, Ahmed , Balmforth, Anthony , Hall, Alistair , Erdmann, Jeanette , Cambien, Francois , Deloukas, Panos , Hengstenberg, Christian , Packard, Chris , Schunkert, Heribert , Ouwehand, Willem , Ford, Ian , Goodall, Alison , Jobling, Mark , Samani, Nilesh , Tomaszewski, Maciej
- Date: 2012
- Type: Text , Journal article
- Relation: The Lancet Vol. 379, no. 9819 (2012), p. 915-922
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
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- Description: Background: A sexual dimorphism exists in the incidence and prevalence of coronary artery disease - men are more commonly affected than are age-matched women. We explored the role of the Y chromosome in coronary artery disease in the context of this sexual inequity. Methods: We genotyped 11 markers of the male-specific region of the Y chromosome in 3233 biologically unrelated British men from three cohorts: the British Heart Foundation Family Heart Study (BHF-FHS), West of Scotland Coronary Prevention Study (WOSCOPS), and Cardiogenics Study. On the basis of this information, each Y chromosome was tracked back into one of 13 ancient lineages defined as haplogroups. We then examined associations between common Y chromosome haplogroups and the risk of coronary artery disease in cross-sectional BHF-FHS and prospective WOSCOPS. Finally, we undertook functional analysis of Y chromosome effects on monocyte and macrophage transcriptome in British men from the Cardiogenics Study. Findings: Of nine haplogroups identified, two (R1b1b2 and I) accounted for roughly 90 of the Y chromosome variants among British men. Carriers of haplogroup I had about a 50 higher age-adjusted risk of coronary artery disease than did men with other Y chromosome lineages in BHF-FHS (odds ratio 1·75, 95 CI 1·20-2·54, p=0·004), WOSCOPS (1·45, 1·08-1·95, p=0·012), and joint analysis of both populations (1·56, 1·24-1·97, p=0·0002). The association between haplogroup I and increased risk of coronary artery disease was independent of traditional cardiovascular and socioeconomic risk factors. Analysis of macrophage transcriptome in the Cardiogenics Study revealed that 19 molecular pathways showing strong differential expression between men with haplogroup I and other lineages of the Y chromosome were interconnected by common genes related to inflammation and immunity, and that some of them have a strong relevance to atherosclerosis. Interpretation: The human Y chromosome is associated with risk of coronary artery disease in men of European ancestry, possibly through interactions of immunity and inflammation. Funding: British Heart Foundation; UK National Institute for Health Research; LEW Carty Charitable Fund; National Health and Medical Research Council of Australia; European Union 6th Framework Programme; Wellcome Trust. © 2012 Elsevier Ltd.
Sport-specific factors predicting player retention in junior cricket
- Authors: Talpey, Scott , Croucher, Tom , Bani-Mustafa, Ahmed , Finch, Caroline
- Date: 2017
- Type: Text , Journal article
- Relation: European Journal of Sport Science Vol. 17, no. 3 (2017), p. 264-270
- Relation: http://purl.org/au-research/grants/nhmrc/565900
- Relation: http://purl.org/au-research/grants/nhmrc/1058737
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- Description: Understanding factors that motivate young athletes to continue participation in sport can help key stakeholders cultivate an environment that fosters long-term participation. This investigation sought to determine the performance and participation factors that influenced continued participation in junior cricket. Administration-level data were collected each annual season across a seven-year period by a community-level junior cricket association in Australia and analysed to identify the performance and participation-based predictors of player retention. All players were males aged <16 years. Players were categorised according to whether they remained in (or departed from) the association at the end of each playing season. A multivariate logistic regression model with a stepwise variable selection was employed to identify significant independent predictors of player retention. The number of innings batted and overs bowled were significant participation-related contributors to junior cricket player retention. Performance factors such as the number of wickets taken and the number of runs scored also significantly influenced player retention. Finally, team age group, the number of previous seasons played and age were also significant factors in player retention. This demonstrates that sufficient opportunity for children to participate in the game and expression of skills competence are key factors for retention in cricket.
- Description: Understanding factors that motivate young athletes to continue participation in sport can help key stakeholders cultivate an environment that fosters long-term participation. This investigation sought to determine the performance and participation factors that influenced continued participation in junior cricket. Administration-level data were collected each annual season across a seven-year period by a community-level junior cricket association in Australia and analysed to identify the performance and participation-based predictors of player retention. All players were males aged <16 years. Players were categorised according to whether they remained in (or departed from) the association at the end of each playing season. A multivariate logistic regression model with a stepwise variable selection was employed to identify significant independent predictors of player retention. The number of innings batted and overs bowled were significant participation-related contributors to junior cricket player retention. Performance factors such as the number of wickets taken and the number of runs scored also significantly influenced player retention. Finally, team age group, the number of previous seasons played and age were also significant factors in player retention. This demonstrates that sufficient opportunity for children to participate in the game and expression of skills competence are key factors for retention in cricket. © 2016 European College of Sport Science.
Marginal longitudinal curves estimated via Bayesian penalized splines
- Authors: Al Kadiri, Mohammad , Bani-Mustafa, Ahmed , Finch, Caroline
- Date: 2010
- Type: Text , Conference paper
- Relation: Australian Statistical Conference 2010 , 6th December, 2010 Fremantle Published in Statistics & Probability Letters Vol. 80 Issue 15-16 Vol. 80, p. 1-19
- Full Text: false
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- Description: The six cities air pollution is used to estimate and investigate the marginal curve of a function describing lung growth for set of children in a longitudinal study. This article proposes penalized regression spline technqiue based ona semiparametric mixed models (MM) framework for an additive model. This smoothing approach fits marginal models for longitudinal unbalanced measurements by using a Bayesian inference approach, implemented using a Markov chain Monte Carlo approach with the Gibbs sampler. The unbalanced case in which missing or different number of measurements for a set of subjects is more practical and common in real life studies. This methodology makes it possible to establish a straightforward approach to similar models using R programming, when it is not possible to do so using existing codes.
Automatic sleep stage identification: difficulties and possible solutions
- Authors: Sukhorukova, Nadezda , Stranieri, Andrew , Ofoghi, Bahadorreza , Vamplew, Peter , Saleem, Muhammad Saad , Ma, Liping , Ugon, Adrien , Ugon, Julien , Muecke, Nial , Amiel, Hélène , Philippe, Carole , Bani-Mustafa, Ahmed , Huda, Shamsul , Bertoli, Marcello , Levy, P , Ganascia, J.G
- Date: 2010
- Type: Text , Conference proceedings
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- Description: The diagnosis of many sleep disorders is a labour intensive task that involves the specialised interpretation of numerous signals including brain wave, breath and heart rate captured in overnight polysomnogram sessions. The automation of diagnoses is challenging for data mining algorithms because the data sets are extremely large and noisy, the signals are complex and specialist's analyses vary. This work reports on the adaptation of approaches from four fields; neural networks, mathematical optimisation, financial forecasting and frequency domain analysis to the problem of automatically determing a patient's stage of sleep. Results, though preliminary, are promising and indicate that combined approaches may prove more fruitful than the reliance on a approach.