7,748 research outputs found
Developmental screening in South Africa : comparing the national developmental checklist to a standardized tool
Background: Worldwide, more than 200 million children in low- and middle-income countries have developmental delays and/or disabilities. In South Africa the only nationally implemented developmental 'screening' tool is integrated as part of 'The Road to Health Booklet (RTHB).
Method: The study employed a comparative cross-sectional within-subject design to evaluate the accuracy of the RTHB developmental checklist against a standardized international tool i.e. the PEDS tools, consisting of the PEDS and PEDS: DM. A total of 201 participants were included through convenience sampling at primary health care facilities in Tshwane, South Africa.
Results: Sensitivity of the RTHB developmental checklist is low, but specificity is high. The RTHB developmental checklist failed to identify more than half the infants at risk of delays or disorders. The nationally implemented developmental checklist is ineffective to identify at-risk infants. It should be adapted and validated or replaced in order to improve identification of at-risk infants
Finite Schur filtration dimension for modules over an algebra with Schur filtration
Let G be GL_N or SL_N as reductive linear algebraic group over a field k of
positive characteristic p. We prove several results that were previously
established only when N 2^N. Let G act rationally on a finitely
generated commutative k-algebra A. Assume that A as a G-module has a good
filtration or a Schur filtration. Let M be a noetherian A-module with
compatible G action. Then M has finite good/Schur filtration dimension, so that
there are at most finitely many nonzero H^i(G,M). Moreover these H^i(G,M) are
noetherian modules over the ring of invariants A^G. Our main tool is a
resolution involving Schur functors of the ideal of the diagonal in a product
of Grassmannians.Comment: 22 pages; final versio
The impact of HIV infection on the presentation of lung cancer in South Africa
Background. Despite the very high background prevalence of HIV and smoking-related diseases in sub-Saharan Africa, very little is known about the presentation of lung cancer in HIV-infected individuals.Methods. We prospectively compared HIV-positive (n=44) and HIV-negative lung cancer patients (n=425) with regard to demographics, cell type, performance status and tumour node metastasis staging at initial presentation.Results. HIV-positive patients were found to be younger than HIV-negative (mean 54.1 (standard deviation 8.4) years v. 60.5 (10) years, p<0.01), more likely to have squamous cell carcinoma (43.2% v. 30.1%, p=0.07) and significantly more likely to have a poor Eastern Cooperative Oncology Group (ECOG) performance status of â„3 (47.7% v. 29.4%, p=0.02). In the case of non-small cell-lung cancer, they were also significantly less likely to have early stage lung cancer (0% v. 10.3%, p=0.02)Â compared with HIV-negative patients.Conclusions. HIV-positive lung cancer patients were younger, significantly more likely to have a poor performance status at presentation and significantly less likely to have early stage lung cancer when compared with HIV-negative patients
Equivalence of switching linear systems by bisimulation
A general notion of hybrid bisimulation is proposed for the class of switching linear systems. Connections between the notions of bisimulation-based equivalence, state-space equivalence, algebraic and inputâoutput equivalence are investigated. An algebraic characterization of hybrid bisimulation and an algorithmic procedure converging in a finite number of steps to the maximal hybrid bisimulation are derived. Hybrid state space reduction is performed by hybrid bisimulation between the hybrid system and itself. By specializing the results obtained on bisimulation, also characterizations of simulation and abstraction are derived. Connections between observability, bisimulation-based reduction and simulation-based abstraction are studied.\ud
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Anticarbamylated protein antibodies are associated with long-term disability and increased disease activity in patients with early inflammatory arthritis:Results from the Norfolk Arthritis Register
Objectives: Anticarbamylated protein (anti-CarP) antibodies are a novel family of autoantibodies recently identified in patients with inflammatory arthritis. The aim of this study was to investigate their association with long-term outcomes of disability and disease activity over 20â
yearsâ follow-up in a cohort of patients with inflammatory polyarthritis (IP). Methods: Norfolk Arthritis Register recruited adults with recent-onset swelling of â„2 joints for â„4â
weeks from 1990 to 2009. At baseline, Health Assessment Questionnaire (HAQ) and 28 joint disease activity scores (DAS28) were obtained, and C reactive protein, rheumatoid factor (RF), anticitrullinated protein antibodies (ACPA) and anti-CarP antibodies were measured. Further HAQ scores and DAS28 were obtained at regular intervals over 20â
years. Generalised estimating equations were used to test the association between anti-CarP antibody status and longitudinal HAQ and DAS28 scores; adjusting for age, gender, smoking status, year of inclusion and ACPA status. Analyses were repeated in subgroups stratified by ACPA status. The relative association of RF, ACPA and anti-CarP antibodies with HAQ and DAS28 scores was investigated using a random effects model. Results: 1995 patients were included; 1310 (66%) were female. Anti-CarP antibodies were significantly associated with more disability and higher disease activity, HAQ multivariate ÎČ-coefficient (95% CI) 0.12 (0.02 to 0.21), and these associations remained significant in the ACPA-negative subgroups. The associations of RF, ACPA and anti-CarP antibodies were found to be additive in the random effects model. Conclusions: Anti-CarP antibodies are associated with increased disability and higher disease activity in patients with IP. Our results suggest that measurement of anti-CarP antibodies may be useful in identifying ACPA-negative patients with worse long-term outcomes. Further, anti-CarP antibody status provided additional information about RF and ACPA
Spatial correlations between MRI-derived wall shear stress and vessel wall thickness in the carotid bifurcation
BACKGROUND: To explore the possibility of creating three-dimensional (3D) estimation models for patient-specific wall thickness (WT) maps using patient-specific and cohort-averaged WT, wall shear stress (WSS), and vessel diameter maps in asymptomatic atherosclerotic carotid bifurcations. METHODS: Twenty subjects (aged 75â±â6 years [meanâ±âstandard deviation], eight women) underwent a 1.5-T MRI examination. Non-gated 3D phase-contrast gradient-echo images and proton density-weighted echo-planar images were retrospectively assessed for WSS, diameter estimation, and WT measurements. Spearman's Ï and scatter plots were used to determine correlations between individual WT, WSS, and diameter maps. A bootstrapping technique was used to determine correlations between 3D cohort-averaged WT, WSS, and diameter maps. Linear regression between the cohort-averaged WT, WSS, and diameter maps was used to predict individual 3D WT. RESULTS: Spearman's Ï averaged over the subjects was -â0.24â±â0.18 (pâ<â0.001) and 0.07â±â0.28 (pâ=â0.413) for WT versus WSS and for WT versus diameter relations, respectively. Cohort-averaged Ï, averaged over 1000 bootstraps, was -â0.56 (95% confidence interval [-â0.74,-â0.38]) for WT versus WSS and 0.23 (95% confidence interval [-â0.06, 0.52]) for WT versus diameter. Scatter plots did not reveal relationships between individual WT and WSS or between WT and diameter data. Linear relationships between these parameters became apparent after averaging over the cohort. Spearman's Ï between the original and predicted WT maps was 0.21â±â0.22 (pâ<â0.001). CONCLUSIONS: With a combination of bootstrapping and cohort-averaging methods, 3D WT maps can be predicted from the individual 3D WSS and diameter maps. The methodology may help to elucidate pathological processes involving WSS in carotid atherosclerosis
Volcanic Ash from the 1999 Eruption of Mount Cameroon Volcano: Characterization and Implications to Health Hazards
Volcanic ash from the 1999 eruption of Mount Cameroon volcano has been characterized for its particle size and shape (by scanning electron microscopy, SEM), and mineralogy (by X-ray diffractometry, XRD). Also the total fluorine (F) content of the ash was determined by the selective ion electrode method. The results show that the Mount Cameroon ash particles have a variety of shapes including fibrous, rounded, subrounded, irregular, angular, eleongated and bladed. All the ash samples have a significant proportion (~ 30%) of ash < 4 ÆĂm in size and thisis classified in occupational medicine as 'thoracic' and 'respirable' ash that is considered harmful to health. The XRD patterns show that the ash contains plagioclase feldspar, enstatite, augite and chromite, which, if fine enough may cause irritation of the respiratory tract, but they are relatively insoluble in the alveolar region. The ash lacks free silica, the main mineral in volcanic ash responsible for causing silicosis. The F concentration in the ash ranges from 46 ÆĂg/ g to 189ÆĂg/g. This is high considering that the lethal dose of F is set internationally at ~ 100ÆĂg/g. This study forms the basis for a long term monitoring of volcanic ash risk and possible mitigation measures of the Mount Cameroon volcano.Keywords: volcanic ash, Mt. Cameroon, health hazardsCendre de Volcan de L'Eruption de 1999 du Mont Cameroun: Caracterisation et Implications aux Risques Sanitaires.La cendre de volcan de l'eruption de 1999 du mont Cameroun a ete caracterisee pour la dimension et la forme de ces particules (en utilisant la microscopie electronique a balayant, SEM), et mineralogie (diffractometrie a rayon X, XRD). En outre toute la teneur en fluor (F) de la cendre a ete determinee par la methode selective d'electrode d'ion. Les resultats prouvent que les particules de cendre du mont Cameroun ont une variete de formes comprenant : les fibreux, les arrondies, les sous arrondies, les irreguliers, les angulaires et les ovales. Tous les echantillons de cendreont une proportion significative de (~ 30 %) de cendre ayant la taille < 4 m et ceci est classifie dans la medecine du travail comme la cendre 'thoracique' et 'respirable' qui est consideree nocif a la sante. Les modeles de XRD montre que la cendre contient le feldspath de plagioclase, l'enstatite, l'augite et la chromite qui, s'ils sont assez fins, peuvent produire l'irritation de la cavite nasale mais sont relativement insolubles dans la region d'aveolaire. La cendre manque de la silice libre, qui est le minerai principal de la cendre volcanique responsable d'engendrer la silicose. La concentration de F dans la cendre s'echelonne de 189 g/g. Ceci est eleve considerant que la dose mortelle de F est place internationalement aux environs de ~ 100 g/g. Cette etude forme la base pour une surveillance a long terme du risque volcanique et des mesures possibles de reduction du volcan de mont Cameroun.Mots cles : cendre de volcan, Mont Cameroun, risques sanitaire
Risks associated with communication delays in infants from underserved South African communities
Contexte: Pour sâĂ©panouir complĂštement les jeunes enfants ont besoin dâun environnement chaud, rĂ©ceptif, enrichi et communicatif pour apprendre le langage social et dâautres compĂ©tences. Les nourrissons et les tout-petits exposĂ©s Ă des risques psychosociaux souffrent dâun manque dâenvironnements enrichissants et pourraient souffrir de retards de communication verbale.
Objectif: Pour étudier la relation entre les risques psychosociaux et les retards de communication verbale chez les nourrissons des communautés non desservies en Afrique du Sud.
Lieu: Services de soins primaires dans le district de Tshwane, en Afrique du Sud.
MĂ©thodes: Une entrevue avec les parents et lâEchelle de CompĂ©tence linguistique pour les Nourrissons de Rossetti ont Ă©tĂ© utilisĂ©s pour rassembler les donnĂ©es de 201 nourrissons de 6 Ă 12 mois provenant de leurs gardiens, sĂ©lectionnĂ©s au moyen dâĂ©chantillonnages de proximitĂ©. On a remarquĂ© un lien entre les retards et les risques de communication verbale (tests Chi carrĂ© et de Fisher). On a utilisĂ© un modĂšle dâanalyse log-linĂ©aire pour modĂ©liser lâeffet simultanĂ© des risques importants sur la probabilitĂ© dâavoir des retards de communication verbale.
RĂ©sultats: On a trouvĂ© des retards de communication verbale chez 13% des nourrissons. Les nourrissons qui vivent avec deux frĂšres ou soeurs ou plus, nĂ©s de mĂšres ĂągĂ©es de 18 Ă 29 ansqui ont leur propre maison, avaient 39% plus de chance dâavoir des retards de communication verbale
Serum vitamin D levels are associated with structural and functional properties of the carotid artery in older men and women
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