Nonlinear models for neural networks.

Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.The most commonly used applications of hidden-layer feed forward neural networks are to fit curves to regression data or to provide a surface from which a classification rule can be found. From a statistical viewpoint, the principle underpinning these networks is that of nonparametric regression with sigmoidal curves being located and scaled so that their sum approximates the data well, and the underlying mechanism is that of nonlinear regression, with the weights of the network corresponding to parameters in the regression model, and the objective function implemented in the training of the network defining the error structure. The aim ofthe present study is to use these statistical insights to critically appraise the reliability and the precision of the predicted outputs from a trained hiddenlayer feed forward neural network

African American Patients’ Intent to Screen for Colorectal Cancer: Do Cultural Factors, Health Literacy, Knowledge, Age and Gender Matter?

African Americans have higher colorectal cancer (CRC) mortality rates compared with all racial/ethnic groups. Research suggests that CRC screening interventions for African Americans target cultural variables. Secondary analysis of data from 817 African-Americans who had not been screened for CRC was conducted to examine: 1) relationships among cultural variables (provider trust, cancer fatalism, health temporal orientation [HTO]), health literacy, and CRC knowledge; 2) age and gender differences; and 3) relationships among cultural variables, health literacy, CRC knowledge, and CRC screening intention. Provider trust, fatalism, HTO, health literacy, and CRC knowledge demonstrated significant relationships among study variables. Stool blood test intention model explained 43% of the variance, with age and gender being significant predictors. Colonoscopy intention model explained 41% of the variance with gender a significant predictor. Results suggest when developing CRC interventions for African Americans, addressing cultural variables is important, but particular attention should be given to age and gender

Fine scale measurement and mapping of uranium in soil solution in soil and plant-soil microcosms, with special reference to depleted uranium

Background and aims: Residues from use of depleted uranium (DU) munitions pose a lasting environmental impact through persistent contamination of soils. Consequently, an understanding of the factors determining the fate of DU in soil is necessary. An understudied factor is the interaction of root exudates with DU. This study describes the use of ‘Single-Cell-Sampling-and-Analysis' (SiCSA) for the first time in soil and investigates the effects of root exudates on DU dissolution. Methods: Soil solutions from soil and plant-soil microcosms containing DU fragments were sampled and analysed using SiCSA and capillary electrophoresis/ICP-MS for organic acids and uranium. Results: Nanolitre volumes of soil solution were sampled and analysed. Soils with DU fragments but no citrate addition showed low uranium concentrations in contrast to those with added citrate. Lupin root exudation gave concentrations up to 8mM citrate and 4.4mM malate in soil solution which solubilised DU fragments yielding transient solution concentrations of up to 30mM. Conclusions: Root exudates solubilise DU giving high localised soil solution concentrations. This should be considered when assessing the environmental risk of DU munitions. The SiCSA method was used successfully in soil for the first time and enables investigations with high spatial and temporal resolution in the rhizosphere. Figur

‘Super disabilities’ vs ‘Disabilities’?:Theorizing the role of ableism in (mis)representational mythology of disability in the marketplace

People with disabilities (PWD) constitute one of the largest minority groups with one in five people worldwide having a disability. While recognition and inclusion of this group in the marketplace has seen improvement, the effects of (mis)representation of PWD in shaping the discourse on fostering marketplace inclusion of socially marginalized consumers remain little understood. Although effects of misrepresentation (e.g., idealized, exoticized or selective representation) on inclusion/exclusion perceptions and cognitions has received attention in the context of ethnic/racial groups, the world of disability has been largely neglected. By extending the theory of ableism into the context of PWD representation and applying it to the analysis of the We’re the Superhumans advertisement developed for the Rio 2016 Paralympic Games, this paper examines the relationship between the (mis)representation and the inclusion/exclusion discourse. By uncovering that PWD misrepresentations can partially mask and/or redress the root causes of exclusion experienced by PWD in their lived realities, it contributes to the research agenda on the transformative role of consumption cultures perpetuating harmful, exclusionary social perceptions of marginalized groups versus contributing to advancement of their inclusion

Decades after the cooperative study: A re-examination of systemic blood pressure in sickle cell disease

Previous studies report lower systemic blood pressures in patients with sickle cell disease (SCD) than in appropriate controls. The etiology of the lower systolic and diastolic blood pressures (SBP and DBP) remains uncertain. Blood pressure measurements from patients followed at our center (UNC cohort) were compared with values obtained from the Cooperative Study of Sickle Cell Disease (CSSCD) and healthy control subjects. Associations of SBP and DBP with clinical and laboratory covariates were performed in the UNC cohort. Patients in the UNC cohort were significantly older and had a higher BMI than those in the CSSCD (p <0.0001). There were no differences in the SBP and DBP between SCD patients in the UNC cohort and control subjects. In the SS/SD/Sβ0 thalassemia group, SBP was higher in the UNC cohort than in the CSSCD (p < 0.0001). On multivariate analysis, significant correlations were noted between SBP and age, BMI, history of hypertension and absolute neutrophil count. Compared with historic controls, SBP was significantly higher in our SCD patient cohort. There was no difference when blood pressure was compared between our patient cohort and control subjects. Age, BMI and neutrophil count may contribute to the modulation of SBP in SCD

Association of pro-inflammatory high-density lipoprotein cholesterol with clinical and laboratory variables in sickle cell disease

Although cholesterol levels are known to be decreased in sickle cell disease (SCD), the level of pro-inflammatory high density lipoprotein cholesterol (proHDL) and its association with clinical complications and laboratory variables has not been evaluated

The Effect of an 8-Week Tai Chi Exercise Program on Physical Functional Performance in Middle-Aged Women

The purpose of this study was to determine the effectiveness of an 8-week Tai Chi Chih exercise program on physical functional performance (PFP) among women aged 45 to 65 years. A quasi-experimental design with a nonequivalent comparison group was used. Forty-one healthy inactive women were assigned to either an intervention group (n = 19) or a comparison group (n = 19). A 60-min Tai Chi Chih exercise class was conducted twice a week for 8 weeks. PFP was measured at baseline and postintervention using the Continuous Scale Physical Functional Performance–10 (CS-PFP 10). Between-group differences were analyzed using one-way analysis of covariance (ANCOVA). After participating in the 8-week program, intervention group participants showed greater improvement in the CS-PFP measures (p .06). However, the comparison group had little changes. The findings from this study suggest that participation in an 8-week Tai Chi Chih exercise program can improve PFP in healthy, community-dwelling middle-aged women.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Urinary Albumin Excretion is Associated with Pulmonary Hypertension in Sickle Cell Disease: Potential Role of Soluble Fms-Like Tyrosine Kinase-1

Pulmonary hypertension (PHT) is reported to be associated with measures of renal function in patients with sickle cell disease (SCD). The purpose of this exploratory study was to determine the relationship between albuminuria and both clinical and laboratory variables in SCD

A pilot study of eptifibatide for treatment of acute pain episodes in sickle cell disease

The contribution of platelet activation to the pathogenesis of sickle cell disease (SCD) remains uncertain. We evaluated the safety and efficacy of eptifibatide, a synthetic peptide inhibitor of the αIIbβ3 receptor, in SCD patients during acute painful episodes

Association of Coagulation Activation with Clinical Complications in Sickle Cell Disease

Background: The contribution of hypercoagulability to the pathophysiology of sickle cell disease (SCD) remains poorly defined. We sought to evaluate the association of markers of coagulation and platelet activation with specific clinical complications and laboratory variables in patients with SCD. Design and Methods: Plasma markers of coagulation activation (D-dimer and TAT), platelet activation (soluble CD40 ligand), microparticle-associated tissue factor (MPTF) procoagulant activity and other laboratory variables were obtained in a cohort of patients with SCD. Tricuspid regurgitant jet velocity was determined by Doppler echocardiography and the presence/history of clinical complications was ascertained at the time of evaluation, combined with a detailed review of the medical records. Results: No significant differences in the levels of D-dimer, TAT, soluble CD40 ligand, and MPTF procoagulant activity were observed between patients in the SS/SD/Sb 0 thalassemia and SC/Sb + thalassemia groups. Both TAT and D-dimer were significantly correlated with measures of hemolysis (lactate dehydrogenase, indirect bilirubin and hemoglobin) and soluble vascular cell adhesion molecule-1. In patients in the SS/SD/Sb 0 thalassemia group, D-dimer was associated with a history of stroke (p = 0.049), TAT was associated with a history of retinopathy (p = 0.0176), and CD40 ligand was associated with the frequency of pain episodes (p = 0.039). In multivariate analyses, D-dimer was associated with reticulocyte count, lactat