Biomedical subjects

K A Shaw

Publications and source records attributed to K A Shaw.

5 recordsLinked to original sources

PubMed2006

Dual energy X-ray absorptiometry body composition and aging in a population-based older cohort.

OBJECTIVE: The aims of this cross-sectional study were (1) to examine the effect of age on body composition in older adults using dual-energy X-ray absorptiometry (DXA) and (2) to evaluate the agreement of DXA with standard indirect anthropometric measures (body mass index (BMI), waist circumference and waist-to-hip ratio (WHR)). RESEARCH METHODS AND PROCEDURES: A population-based sample of 731 adults aged between 50 and 79 years underwent measurement of BMI, waist circumference, WHR, DXA total body fat mass, DXA % total body fat, DXA % trunk fat and DXA lean body mass. Linear regression was used to test for trend in measures of body composition between age categories in men and women. Partial correlations and Bland-Altman analysis were used to examine the agreement of DXA measures with indirect measures. RESULTS: DXA lean body mass decreased significantly with increasing age in both sexes (P<0.05). In males, BMI (P=0.01) and body weight (P<0.01) decreased with age, and in females, WHR (P=0.05), DXA % total fat (P=0.02) and DXA % trunk fat (P=0.05) increased with age. There was good agreement between DXA measures of fatness and indirect anthropometric measures, except for WHR, which showed greater variability in its comparisons with DXA. CONCLUSION: Using the highly sensitive and direct DXA method of measuring body composition, a decline in lean body mass and an increase in adiposity was observed with aging. Except for WHR, indirect anthropometric measures generally showed high levels of agreement with DXA fat measures in this older cohort.

Absorptiometry, Photon↗

PubMed2002

Attitudes and practices of general practitioners in the diagnosis and management of attention-deficit/hyperactivity disorder.

OBJECTIVE: To assess understanding of, and actual and potential roles in management of attention-deficit/hyperactivity disorder (ADHD) among GPs. METHODS: A cross-sectional questionnaire survey of Queensland GPs selected randomly from the Royal Australian College of General Practitioners directory of members was carried out. Main outcome measures were knowledge levels of ADHD, current management practices, referral patterns and self-perceived information and training needs. RESULTS: Three hundred and ninety-nine GPs returned a completed questionnaire (response rate 76%). Roles identified by GPs were: the provisional diagnosis of ADHD and referral to specialist services for confirmation of the diagnosis and initiation of management; assistance with monitoring progress once a management plan was in place; education of the child and their family regarding the disorder; and liaison with the school where necessary. Perceived barriers to increased involvement of GPs were: time and resource constraints of general practice; concerns regarding abuse and addiction liability of prescription stimulants; complex diagnostic issues associated with childhood behavioural problems; and lack of training and education regarding ADHD. CONCLUSIONS: General practitioners identify a role for themselves in ADHD care that is largely supportive in nature and involves close liaison with specialist services.

Adult↗

PubMed2001

Interrater reliability of the active-knee-extension test for hamstring length in school-aged children.

PURPOSE: The purpose of this study was to determine the interrater reliability of the active knee-extension test (AKET) using a stabilizing apparatus to measure hamstring length. METHODS: One hundred one subjects (53 girls, 48 boys) ranging in age from 10 to 13 years with no known neuromuscular problems participated. The AKET was performed with subjects lying supine with the hip flexed to 90 degrees with a stabilization device attached to a plinth. Next, subjects were instructed to actively extend the knee until the rater detected myoclonus. Then, the rater flexed the knee until myoclonus subsided and the knee angle was measured with a blinded goniometer. This procedure was repeated by each of three raters. RESULTS: Data were analyzed using ICC (2,1) demonstrating good interrater reliability of 0.79. CONCLUSION: Our results suggest that the AKET, when used with the stabilizing apparatus, demonstrates good interrater reliability for children aged 10 to 13 years.

Journal Article↗

PubMed2000

Radical pruning: a method to construct skeleton radial basis function networks.

Trained radial basis function networks are well-suited for use in extracting rules and explanations because they contain a set of locally tuned units. However, for rule extraction to be useful, these networks must first be pruned to eliminate unnecessary weights. The pruning algorithm cannot search the network exhaustively because of the computational effort involved. It is shown that using multiple pruning methods with smart ordering of the pruning candidates, the number of weights in a radial basis function network can be reduced to a small fraction of the original number. The complexity of the pruning algorithm is quadratic (instead of exponential) in the number of network weights. Pruning performance is shown using a variety of benchmark problems from the University of California, Irvine machine learning database.

Algorithms↗

PubMed1991

The rabbit retina: a long-term model system for aluminum-induced neurofibrillary degeneration.

Aluminum (Al) was injected into the rabbit eye as a potential long-term model system for Al-induced neurofibrillary degeneration (NFD). Neurofibrillary tangles made up of 10 nm phosphorylated neurofilaments were observed in a subpopulation of retinal ganglion cells, located primarily in the peripheral retina. The distribution of affected cells suggested a differential susceptibility of ganglion cells to Al intoxication. Importantly, none of the animals demonstrated any of the central neurological dysfunctions characteristic of previous Al intoxication models. The retinal model should allow for long-term studies of Al intoxication and its potential relationship to neurofibrillary degenerative disorders such as Alzheimer's disease.

Aluminum↗