A comparison of two methods for the calculation of accumulated oxygen deficit

The aim of this study was to compare accumulated oxygen deficit data derived using two different exercise protocols with the aim of producing a less time-consuming test specifically for use with athletes. Six road and four track male endurance cyclists performed two series of cycle ergometer tests. The first series involved five 10 min sub-maximal cycle exercise bouts, a (V) over dotO(2peak) test and a 115% (V) over dotO(2peak) test. Data from these tests were used to estimate the accumulated oxygen deficit according to the calculations of Medbo et al. (1988). In the second series of tests, participants performed a 15 min incremental cycle ergometer test followed, 2 min later, by a 2 min variable resistance test in which they completed as much work as possible while pedalling at a constant rate. Analysis revealed that the accumulated oxygen deficit calculated from the first series of tests was higher (P< 0.02) than that calculated from the second series: 52.3 +/- 11.7 and 43.9 +/- 6.4 ml . kg(-1), respectively (mean +/- s). Other significant differences between the two protocols were observed for (V) over dot O-2peak, total work and maximal heart rate; all were higher during the modified protocol (P

Promoting better use of the PSA test in general practice: Randomized controlled trial of educational strategies based on outreach visits and mailout

Background. Prostate-specific antigen (PSA) testing for prostate cancer is controversial. Demand for PSA testing is likely to rise in the UK, Australia and other western countries. Primary care needs to develop appropriate strategies to respond to this demand. Objectives. Our aim was to compare the effectiveness of educational outreach visits (EOVs) and mailout strategies targeting PSA testing in Australian primary care. Methods. A randomized controlled trial was conducted in general practices in southern Adelaide. The main outcome measures at baseline, 6 months and 12 months post-intervention were PSA testing rates and GP knowledge in key areas relating to prostate cancer and PSA testing. Results. The interventions were able to demonstrate a change in clinical practice. In the 6 months post-intervention, median PSA testing rate in the EOV group was significantly lower than in the postal group, which in turn was significantly lower than the control group (P < 0.001). Statistically significant differences were not, however, maintained in the 6-12 month post-intervention period. The EOV group, at 6 months follow-up, had a significantly greater proportion of 'correct' responses than the control group to questions about prostate cancer treatment effectiveness (P = 0.004) and endorsement of PSA screening by professional bodies (P = 0.041). Conclusions. Primary care has a central role in PSA testing for prostate cancer. Clinical practice in this area is receptive to evidence-based interventions.

Genetic assignment methods for the direct, real-time estimation of migration rate: a simulation-based exploration of accuracy and power

Genetic assignment methods use genotype likelihoods to draw inference about where individuals were or were not born, potentially allowing direct, real-time estimates of dispersal. We used simulated data sets to test the power and accuracy of Monte Carlo resampling methods in generating statistical thresholds for identifying F-0 immigrants in populations with ongoing gene flow, and hence for providing direct, real-time estimates of migration rates. The identification of accurate critical values required that resampling methods preserved the linkage disequilibrium deriving from recent generations of immigrants and reflected the sampling variance present in the data set being analysed. A novel Monte Carlo resampling method taking into account these aspects was proposed and its efficiency was evaluated. Power and error were relatively insensitive to the frequency assumed for missing alleles. Power to identify F-0 immigrants was improved by using large sample size (up to about 50 individuals) and by sampling all populations from which migrants may have originated. A combination of plotting genotype likelihoods and calculating mean genotype likelihood ratios (D-LR) appeared to be an effective way to predict whether F-0 immigrants could be identified for a particular pair of populations using a given set of markers.

Patients with neck pain demonstrate reduced electromyographic activity of the deep cervical flexor muscles during performance of the craniocervical flexion test

Study Design. Cross-sectional study. Objective. The present study compared activity of deep and superficial cervical flexor muscles and craniocervical flexion range of motion during a test of craniocervical flexion between 10 patients with chronic neck pain and 10 controls. Summary of Background Data. Individuals with chronic neck pain exhibit reduced performance on a test of craniocervical flexion, and training of this maneuver is effective in management of neck complaints. Although this test is hypothesized to reflect dysfunction of the deep cervical flexor muscles, this has not been tested. Methods. Deep cervical flexor electromyographic activity was recorded with custom electrodes inserted via the nose and fixed by suction to the posterior mucosa of the oropharynx. Surface electrodes were placed over the superficial neck muscles ( sternocleidomastoid and anterior scalene). Root mean square electromyographic amplitude and craniocervical flexion range of motion was measured during five incremental levels of craniocervical flexion in supine. Results. There was a strong linear relation between the electromyographic amplitude of the deep cervical flexor muscles and the incremental stages of the craniocervical flexion test for control and individuals with neck pain ( P = 0.002). However, the amplitude of deep cervical flexor electromyographic activity was less for the group with neck pain than controls, and this difference was significant for the higher increments of the task ( P < 0.05). Although not significant, there was a strong trend for greater sternocleidomastoid and anterior scalene electromyographic activity for the group with neck pain. Conclusions. These data confirm that reduced performance of the craniocervical flexion test is associated with dysfunction of the deep cervical flexor muscles and support the validity of this test for patients with neck pain.

Electromagnetic fields inside a lossy, multilayered spherical head phantom excited by MRI coils: models and methods

The precise evaluation of electromagnetic field (EMF) distributions inside biological samples is becoming an increasingly important design requirement for high field MRI systems. In evaluating the induced fields caused by magnetic field gradients and RF transmitter coils, a multilayered dielectric spherical head model is proposed to provide a better understanding of electromagnetic interactions when compared to a traditional homogeneous head phantom. This paper presents Debye potential (DP) and Dyadic Green's function (DGF)-based solutions of the EMFs inside a head-sized, stratified sphere with similar radial conductivity and permittivity profiles as a human head. The DP approach is formulated for the symmetric case in which the source is a circular loop carrying a harmonic-formed current over a wide frequency range. The DGF method is developed for generic cases in which the source may be any kind of RF coil whose current distribution can be evaluated using the method of moments. The calculated EMFs can then be used to deduce MRI imaging parameters. The proposed methods, while not representing the full complexity of a head model, offer advantages in rapid prototyping as the computation times are much lower than a full finite difference time domain calculation using a complex head model. Test examples demonstrate the capability of the proposed models/methods. It is anticipated that this model will be of particular value for high field MRI applications, especially the rapid evaluation of RF resonator (surface and volume coils) and high performance gradient set designs.

Oral glucose tolerance test in children and adolescents: Positives and pitfalls

Objectives: To describe the glycaemic status (assessed by an oral glucose tolerance test (OGTT)) and associated comorbidities in a cohort of Australian children and adolescents at risk of insulin resistance and impaired glucose homeostasis (IGH). Methods: Twenty-one children and adolescents (three male, 18 female) (18 Caucasian, one Indigenous, two Asian) (20 obese, one lipodystrophy) referred to the Paediatric Endocrinology and Diabetes Clinic underwent a 2-h OGTT with plasma glucose and insulin measured at baseline, + 60 and + 120 min. If abnormal, the OGTT was repeated. Results: The mean (SD) age was 14.2 (1.6) years, BMI 38.8 (7.0) kg/m(2) and BMI-SDS 3.6 (0.6). Fourteen patients had fasting insulin levels >21 mU/L. Type 2 diabetes mellitus was diagnosed in one patient, impaired glucose tolerance (IGT) in four patients and impaired fasting glycaemia (IFG) in one patient. Despite no weight loss, only one patient had a persistently abnormal OGTT on repeat testing. Three patients with IGH were medicated with risperidone at the time of the initial OGTT. One patient who had persistent IGT had continued risperidone. The other two patients had initial OGTT results of IGT and diabetes mellitus type 2. They both ceased risperidone between tests and repeat OGTT showed normal glycaemic status. Conclusions: Use of fasting glucose alone may miss cases of IGH. Diagnosis of IGT should not be made on one test alone. Interpretation of glucose and insulin responses in young people is limited by lack of normative data. Larger studies are needed to generate Australian screening recommendations. Further assessment of the potential adverse effects of atypical antipsychotic medication on glucose homeostasis in this at-risk group is important.

The comprehensive osteoarthritis test: a simple index for measurement of treatment effects in clinical trials

Objective. To assess the measurement properties of a simple index of symptom severity in osteoarthritis (OA) of the hips and knees. Methods. Both the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the proposed new Comprehensive Osteoarthritis Test (COAT) instrument were completed weekly by 125 subjects in the context of a randomized, 12-week, 3 parallel-arm clinical trial. The reliabilities of the various scales were assessed on a weekly basis by use of Cronbach's alpha coefficients. The validity of the COAT total scale was assessed by correlation with the WOMAC total scale on a weekly basis with correlation coefficients, and in terms of the correlations between subject-level intercepts and slopes over time. The relative responsiveness of the WOMAC and COAT total scales was assessed using a multilevel (longitudinal) multivariate (WOMAC, COAT) linear model. Results. The WOMAC and COAT total scales were highly reliable (mean over weeks: WOMAC alpha = 0.98; COAT alpha = 0.97). The correlations between the WOMAC and COAT scales were very high (mean over weeks = 0.92; subject-level intercepts = 0.91, slopes = 0.88). The COAT total scale was significantly more responsive than the WOMAC total scale in the active treatment (34.8% improvement vs 26.8%; p = 0.002). Conclusion. The COAT total scale is simple to administer, reliable, valid, and responsive to treatment effects.

Spatio-temporal scanning and statistical test of the accelerating moment release (AMR) model using Australian earthquake data

The Accelerating Moment Release (AMR) preceding earthquakes with magnitude above 5 in Australia that occurred during the last 20 years was analyzed to test the Critical Point Hypothesis. Twelve earthquakes in the catalog were chosen based on a criterion for the number of nearby events. Results show that seven sequences with numerous events recorded leading up to the main earthquake exhibited accelerating moment release. Two occurred near in time and space to other earthquakes preceded by AM R. The remaining three sequences had very few events in the catalog so the lack of AMR detected in the analysis may be related to catalog incompleteness. Spatio-temporal scanning of AMR parameters shows that 80% of the areas in which AMR occurred experienced large events. In areas of similar background seismicity with no large events, 10 out of 12 cases exhibit no AMR, and two others are false alarms where AMR was observed but no large event followed. The relationship between AMR and Load-Unload Response Ratio (LURR) was studied. Both methods predict similar critical region sizes, however, the critical point time using AMR is slightly earlier than the time of the critical point LURR anomaly.

The functions of societies and the evolution of group living: Spider societies as a test case

Many models have been advanced to suggest how different expressions of sociality have evolved and are maintained. However these models ignore the function of groups for the particular species in question. Here we present a new perspective on sociality where the function of the group takes a central role. We argue that sociality may have primarily a reproductive, protective, or foraging function, depending on whether it enhances the reproductive, protective or foraging aspect of the animal's life (sociality may serve a mixture of these functions). Different functions can potentially cause the development of the same social behaviour. By identifying which function influences a particular social behaviour we can determine how that social behaviour will change with changing conditions, and which models are most pertinent. To test our approach we examined spider sociality, which has often been seen as the poor cousin to insect sociality. By using our approach we found that the group characteristics of eusocial insects is largely governed by the reproductive function of their groups, while the group characteristics of social spiders is largely governed by the foraging function of the group. This means that models relevant to insects may not be relevant to spiders. It also explains why eusocial insects have developed a strict caste system while spider societies are more egalitarian. We also used our approach to explain the differences between different types of spider groups. For example, differences in the characteristics of colonial and kleptoparasitic groups can be explained by differences in foraging methods, while differences between colonial and cooperative spiders can be explained by the role of the reproductive function in the formation of cooperative spider groups. Although the interactions within cooperative spider colonies are largely those of a foraging society, demographic traits and colony dynamics are strongly influenced by the reproductive function. We argue that functional explanations help to understand the social structure of spider groups and therefore the evolutionary potential for speciation in social spiders.

Axisymmetric shock wave interaction with a cone: a benchmark test

Results of the benchmark test are presented of comparing numerical schemes solving shock wave of M-s = 2.38 in nitrogen and argon interacting with a 43 degrees semi-apex angle cone and corresponding experiments. The benchmark test was announced in Shock Waves Vol. 12, No. 4, in which we tried to clarify the effects of viscosity and heat conductivity on shock reflection in conical flows. This paper summarizes results of ten numerical and two experimental applications. State of the art in studies regarding the shock/cone interaction is clarified.

A theoretical comparison of two optimization methods for radiofrequency drive schemes in high frequency MRI resonators

In this paper, numerical simulations are used in an attempt to find optimal Source profiles for high frequency radiofrequency (RF) volume coils. Biologically loaded, shielded/unshielded circular and elliptical birdcage coils operating at 170 MHz, 300 MHz and 470 MHz are modelled using the FDTD method for both 2D and 3D cases. Taking advantage of the fact that some aspects of the electromagnetic system are linear, two approaches have been proposed for the determination of the drives for individual elements in the RF resonator. The first method is an iterative optimization technique with a kernel for the evaluation of RF fields inside an imaging plane of a human head model using pre-characterized sensitivity profiles of the individual rungs of a resonator; the second method is a regularization-based technique. In the second approach, a sensitivity matrix is explicitly constructed and a regularization procedure is employed to solve the ill-posed problem. Test simulations show that both methods can improve the B-1-field homogeneity in both focused and non-focused scenarios. While the regularization-based method is more efficient, the first optimization method is more flexible as it can take into account other issues such as controlling SAR or reshaping the resonator structures. It is hoped that these schemes and their extensions will be useful for the determination of multi-element RF drives in a variety of applications.

A Test of Performance of Breast MRI Interpretation in a Multicentre Screening Study

Objectives: The aim of this study was to assess the consistency and performance of radiologists interpreting breast magnetic resonance imaging (MRI) examinations. Materials and Methods: Two test sets of eight cases comprising cancers, benign disease, technical problems and parenchymal enhancement were prepared from two manufacturers' equipment (X and Y) and reported by 15 radiologists using the recording form and scoring system of the UK MRI breast screening study [(MAgnetic Resonance Imaging in Breast Screening (MARIBS)]. Variations in assessments of morphology, kinetic scores and diagnosis were measured by assessing intraobserver and interobserver variability and agreement. The sensitivity and specificity of reporting performances was determined using receiver operating characteristic (ROC) curve analysis. Results: Intraobserver variation was seen in 13 (27.7%) of 47 of the radiologists' conclusions (four technical and seven pathological differences). Substantial interobserver variation was observed in the scores recorded for morphology, pattern of enhancement, quantification of enhancement and washout pattern. The overall sensitivity of breast MRI was high [88.6%, 95% confidence interval (CI) 77.4-94.7%], combined with a specificity of 69.2% (95% CI 60.5-76.7%). The sensitivities were similar for the two test sets (P=.3), but the specificity was significantly higher for the Manufacturer X dataset (P

Assessment of statistical change criteria used to define significant change in neuropsychological test performance following cardiac surgery

Objective: This paper compares four techniques used to assess change in neuropsychological test scores before and after coronary artery bypass graft surgery (CABG), and includes a rationale for the classification of a patient as overall impaired. Methods: A total of 55 patients were tested before and after surgery on the MicroCog neuropsychological test battery. A matched control group underwent the same testing regime to generate test–retest reliabilities and practice effects. Two techniques designed to assess statistical change were used: the Reliable Change Index (RCI), modified for practice, and the Standardised Regression-based (SRB) technique. These were compared against two fixed cutoff techniques (standard deviation and 20% change methods). Results: The incidence of decline across test scores varied markedly depending on which technique was used to describe change. The SRB method identified more patients as declined on most measures. In comparison, the two fixed cutoff techniques displayed relatively reduced sensitivity in the detection of change. Conclusions: Overall change in an individual can be described provided the investigators choose a rational cutoff based on likely spread of scores due to chance. A cutoff value of ≥20% of test scores used provided acceptable probability based on the number of tests commonly encountered. Investigators must also choose a test battery that minimises shared variance among test scores.

Validation of the Action Research Arm Test using item response theory in patients after stroke

Objective: To validate the unidimensionality of the Action Research Arm Test (ARAT) using Mokken analysis and to examine whether scores of the ARAT can be transformed into interval scores using Rasch analysis. Subjects and methods: A total of 351 patients with stroke were recruited from 5 rehabilitation departments located in 4 regions of Taiwan. The 19-item ARAT was administered to all the subjects by a physical therapist. The data were analysed using item response theory by non-parametric Mokken analysis followed by Rasch analysis. Results: The results supported a unidimensional scale of the 19-item ARAT by Mokken analysis, with the scalability coefficient H = 0.95. Except for the item pinch ball bearing 3rd finger and thumb'', the remaining 18 items have a consistently hierarchical order along the upper extremity function's continuum. In contrast, the Rasch analysis, with a stepwise deletion of misfit items, showed that only 4 items (grasp ball'', grasp block 5 cm(3)'', grasp block 2.5 cm(3)'', and grip tube 1 cm(3)'') fit the Rasch rating scale model's expectations. Conclusion: Our findings indicated that the 19-item ARAT constituted a unidimensional construct measuring upper extremity function in stroke patients. However, the results did not support the premise that the raw sum scores of the ARAT can be transformed into interval Rasch scores. Thus, the raw sum scores of the ARAT can provide information only about order of patients on their upper extremity functional abilities, but not represent each patient's exact functioning.

Should an oral glucose tolerance test be performed routinely in all renal transplant recipients?

Posttransplantation diabetes (PTD) contributes to cardiovascular disease and graft loss in renal transplant recipients (RTR). Current recommendations advise fasting blood glucose (FBG) as the screening and diagnostic test of choice for PTD. This study sought to determine (1) the predictive power of FBG with respect to 2-h blood glucose (2HBG) and (2) the prevalence of PTD using FBG and 2HBG compared with that using FBG alone, in prevalent RTR. A total of 200 RTR (mean age 52 yr; 59% male; median transplant duration 6.6 yr) who were >6 mo posttransplantation and had no known history of diabetes were studied. Patients with FBG