Classification of form under heterogeneity and non-isotropic errors

A number of areas related to learning under supervision have not been fully investigated, particularly the possibility of incorporating the method of classification into shape analysis. In this regard, practical ideas conducive to the improvement of form classification are the focus of interest. Our proposal is to employ a hybrid classifier built on Euclidean Distance Matrix Analysis (EDMA) and Procrustes distance, rather than generalised Procrustes analysis (GPA). In empirical terms, it has been demonstrated that there is notable difference between the estimated form and the true form when EDMA is used as the basis for computation. However, this does not seem to be the case when GPA is employed. With the assumption that no association exists between landmarks, EDMA and GPA are used to calculate the mean form and diagonal weighting matrix to build superimposing classifiers. As our findings indicate, with the use of EDMA estimators, the superimposing classifiers we propose work extremely well, as opposed to the use of GPA, as far as both simulated and real datasets are concerned

Identification of sources from which doctors in the private sector obtain information on HIV and AIDS

Background: Doctors need to constantly update their knowledge and obtain information in order to practise high-quality medicine. Antiretroviral drugs have been available only since around 1996, therefore many of the doctors who were trained prior to 1996 would not have received any formal training in the management of HIV and AIDS patients. Where doctors source their general medical knowledge has been established, but little is known about where doctors source information on HIV/ AIDS. This study investigated where private sector doctors from the eThekwini Metro obtain information on HIV and AIDS for patient management.Methods: A descriptive cross-sectional study among 133 private general practitioners (GPs) and 33 specialist doctors in the eThekwini Metro of KwaZulu-Natal, South Africa, was conducted with the use of questionnaires. The questionnaires were analysed using SPSS version 15. A p value of < 0.05 was considered statistically significant.Results: The majority of the doctors (92.4%) obtained information on HIV and AIDS from journals. Continuing Medical Education (CME), textbooks, pharmaceutical representatives, workshops, colleagues and conferences were identified as other sources of information, while only 35.7% of doctors were found to use the internet for information. GPs and specialists differed significantly with regard to their reliance on colleagues (52.9% versus 72.7%; p < 0.05) and conferences (48.6% versus 78.8%; p < 0.05) as sources of HIV information. More than 90% of doctors reported that CME courses contributed to better management of HIV and AIDS patients.Conclusion: Private sector doctors in the eThekwini Metro obtain information on HIV from reliable sources in order to have up-to-date knowledge on the management of HIV-infected patients.Keywords: HIV/AIDS; source of information; private sector doctors; journal

Circular local likelihood

We introduce a class of local likelihood circular density estimators, which includes the kernel density estimator as a special case. The idea lies in optimizing a spatially weighted version of the log-likelihood function, where the logarithm of the density is locally approximated by a periodic polynomial. The use of von Mises density functions as weights reduces the computational burden. Also, we propose closed-form estimators which could form the basis of counterparts in the multidimensional Euclidean setting. Simulation results and a real data case study are used to evaluate the performance and illustrate the results

A note on nonparametric estimation of circular conditional densities

The conditional density offers the most informative summary of the relationship between explanatory and response variables. We need to estimate it in place of the simple conditional mean when its shape is not well-behaved. A motivation for estimating conditional densities, specific to the circular setting, lies in the fact that a natural alternative of it, like quantile regression, could be considered problematic because circular quantiles are not rotationally equivariant. We treat conditional density estimation as a local polynomial fitting problem as proposed by \cite{Fan et al.:1996} in the euclidean setting, and discuss a class of estimators in the cases when the conditioning variable is either circular or linear. Asymptotic properties for some members of the proposed class are derived. The effectiveness of the methods for finite sample sizes is illustrated by simulation experiments and an example using real data

Nonparametric estimating equations for circular probability density functions and their derivatives

We propose estimating equations whose unknown parameters are the values taken by a circular density and its derivatives at a point. Specifically, we solve equations which relate local versions of population trigonometric moments with their sample counterparts. Major advantages of our approach are: higher order bias without asymptotic variance inflation, closed form for the estimators, and absence of numerical tasks. We also investigate situations where the observed data are dependent. Theoretical results along with simulation experiments are provided

Risky sexual behaviours of high-school pupils in an era of HIV and AIDS

Objective. To identify risky sexual behaviours and demographic factors that place high-school pupils at risk of HIV and AIDS. Methods. A cross-sectional study was undertaken to explore factors influencing the sexual behaviour of high-school pupils (mean age 15.4 years; SD 1.11). Structured self-reported questionnaires were completed by all grade 10 pupils (N=805) at all the Wentworth, Durban, public high schools. Results. Significant gender differences in sexual practices were reported, such as males being more likely to engage in sexual activity than females (OR 4.92;

Highly polarized electrically driven single-photon emission from a non-polar InGaN quantum dot

© 2017 Author(s). Nitride quantum dots are well suited for the deterministic generation of single photons at high temperatures. However, this material system faces the challenge of large in-built fields, decreasing the oscillator strength and possible emission rates considerably. One solution is to grow quantum dots on a non-polar plane; this gives the additional advantage of strongly polarized emission along one crystal direction. This is highly desirable for future device applications, as is electrical excitation. Here, we report on electroluminescence from non-polar InGaN quantum dots. The emission from one of these quantum dots is studied in detail and found to be highly polarized with a degree of polarization of 0.94. Single-photon emission is achieved under excitation with a constant current giving a g(2)(0) correlation value of 0.18. The quantum dot electroluminescence persists up to temperatures as high as 130 K

Experiences of acquired brain injury survivors participating in online and hybrid performance arts programmes: an ethnographic study

Background: Performance arts can benefit people with acquired brain injury (ABI). This study explored the online delivery during COVID-19 restrictions, of a performance art intervention through the experiences of participants, artists and facilitators. Methods: Two community-based programmes were delivered. Online ethnographic observations and semi-structured interviews with participants, artists and facilitators were completed. Results: The programmes benefited participants by addressing loneliness and isolation; building confidence through peer support; improving physical limitations through movement; improving communication through music and vocal work; and using poetry, visual arts, metaphor and performance to make sense of participants’ experiences. Participants had mixed experiences of participation, but it was an acceptable alternative to in-person arts interventions for those who overcame digital challenges. Conclusions: ABI survivors can engage in online performance art programmes and find participation valuable for their health, well-being, and recovery. More work is needed to explore the generalisability of these findings, especially given digital poverty

Inspiratory threshold loading reduces lipoperoxidation in obese and normal-weight subjects

Obesity is related to increased oxidative stress. Although low-intensity physical exercise reduces oxidative stress, obese subjects may show exercise intolerance. For these subjects, inspiratory threshold loading could be an alternative tool to reduce oxidative stress. We investigated the effects of inspiratory threshold loading on biomarkers of oxidative stress in obese and normal-weight subjects. Twenty obese (31.4 ± 6 years old, 10 men and 10 women, 37.5 ± 4.7 kg/m2) and 20 normal-weight (29.4 ± 8 years old, 10 men and 10 women, 23.2 ± 1.5 kg/m2) subjects matched for age and gender participated in the study. Maximal inspiratory pressure (MIP) was assessed by a pressure transducer. Blood sampling was performed before and after loading and control protocols to assess thiobarbituric acid reactive substances (TBARS), protein carbonylation, and reduced glutathione. Inspiratory threshold loading was performed at 60% MIP and maintained until task failure. The 30-min control protocol was performed at 0 cmH2O. Our results demonstrated that inspiratory threshold loading reduced TBARS across time in obese (6.21 ± 2.03 to 4.91 ± 2.14 nmol MDA/ml) and normal-weight subjects (5.60 ± 3.58 to 4.69 ± 2.80 nmol MDA/ml; p = 0.007), but no change was observed in protein carbonyls and glutathione in both groups. The control protocol showed no significant changes in TBARS and protein carbonyls. However, reduced glutathione was increased across time in both groups (obese: from 0.50 ± 0.37 to 0.56 ± 0.35 μmol GSH/ml; normal-weight: from 0.61 ± 0.11 to 0.81 ± 0.23 μmol GSH/ml; p = 0.002). These findings suggest that inspiratory threshold loading could be potentially used as an alternative tool to reduce oxidative stress in both normal-weight and obese individuals

Outbreak of West Nile virus causing severe neurological involvement in children, Nuba Mountains, Sudan, 2002.

An atypical outbreak of West Nile virus (WNV) occurred in Ngorban County, South Kordophan, Sudan, from May to August 2002. We investigated the epidemic and conducted a case-control study in the village of Limon. Blood samples were obtained for cases and controls. Patients with obvious sequelae underwent cerebrospinal fluid (CSF) sampling as well. We used enzyme-linked immunosorbent assay (ELISA) and neutralization tests for laboratory diagnosis and identified 31 cases with encephalitis, four of whom died. Median age was 36 months. Bivariate analysis did not reveal any significant association with the risk factors investigated. Laboratory analysis confirmed presence of IgM antibodies caused by WNV in eight of 13 cases, indicative of recent viral infection. The unique aspects of the WNW outbreak in Sudan, i.e. disease occurrence solely among children and the clinical domination of encephalitis, involving severe neurological sequelae, demonstrate the continuing evolution of WNV virulence. The spread of such a virus to other countries or continents cannot be excluded