9,419 research outputs found
Isolated output for class-D dc amplifiers
Transformer-coupled output stage is used with pulse-width modulated class-D dc amplifiers. Circuit is comprised of two channels corresponding to negative and positive input signals. Amplitude of secondary-current triangular pulse is function of duration of driving pulse. Therefore, circuit converts pulse-width modulated driving signal to pulse-amplitude modulated signal
The Sure Start Mellow Valley area Through the lens of a camera
This report gives an account of a participatory evaluation conducted using photography within the Sure Start Mellow Valley area. Information about the current status of the Sure Start programme and the plans for the future are first provided. The report then describes the research that was undertaken and presents and discusses the findings
Successful paediatric HIV treatment in rural primary care in Africa
<p>Objective: Clinical outcomes of HIV-infected children on antiretroviral treatment (ART) in a decentralised, nurse/counsellor-led programme.</p>
<p>Design: Clinical cohort.</p>
<p>Setting: KwaZulu-Natal, South Africa.</p>
<p>Patients: HIV-infected children aged <= 15 years on ART, June 2004-2008.</p>
<p>Main outcome measures: Survival according to baseline characteristics including age, WHO clinical stage, haemoglobin and CD4%, was assessed in Kaplan-Meier analyses. Hazard ratios for mortality were estimated using Cox proportional hazards regression and changes in laboratory parameters and weight-for-age z scores after 6-12 months' treatment were calculated.</p>
<p>Results: 477 HIV-infected children began ART at a median age of 74 months (range 4-180), median CD4 count (CD4%) of 433 cells/mm(3) (17%) and median HIV viral load of log 4.2 copies/ml; 105 (22%) were on treatment for tuberculosis and 317 (76.6%) were WHO stage 3/4. There were significant increases after ART initiation in CD4% (17% vs 22%; p<0.001), haemoglobin (9.9 vs 11.7 g/l; p <= 0.001) and albumin (30 vs 36 g/l; p <= 0.001). 32 (6.7%) children died over 732 child-years of follow-up (43.7 deaths/1000 child-years; 95% CI 32.7 to 58.2), 17 (53.1%) within 90 days of treatment initiation; median age of death was 84 (IQR 10-181) months. Children with baseline haemoglobin <= 8 g/l were more likely to die (adjusted HR 4.5; 95% CI 1.6 to 12.3), as were those aged <18 months compared with >60 months (adjusted HR 3.2; 95% CI 1.2 to 9.1).</p>
<p>Conclusions Good clinical outcomes in HIV-infected children on ART are possible in a rural, decentralised service. Few young children are on ART, highlighting the urgent need to identify HIV-exposed infants.</p>
HIV status, breastfeeding modality at 5 months and postpartum maternal weight changes over 24 months in rural South Africa
ObjectiveTo determine the effect of infant feeding practices on postpartum weight change among HIV-infected and -uninfected women in South Africa.MethodsIn a non-randomised intervention cohort study of antiretroviral therapy-naïve women in South Africa, infants were classified as exclusive (EBF), mixed (MF) or non-breastfed (NBF) at each visit. We analysed infant feeding cumulatively from birth to 5 months using 24-hour feeding history (collected weekly for each of the preceding 7 days). Using generalised estimating equation mixed models, allowing for repeated measures, we compared postpartum weight change (kg) from the first maternal postpartum weight within the first 6 weeks (baseline weight) to each subsequent visit through 24 months among 2340 HIV-infected and -uninfected women with live births and at least two postpartum weight measurements.ResultsHIV-infected (?0.2 kg CI: ?1.7 to 1.3 kg; P = 0.81) and -uninfected women (?0.5 kg; 95% CI: ?2.1 to 1.2 kg; P = 0.58) had marginal non-significant weight loss from baseline to 24 months postpartum. Adjusting for HIV status, socio-demographic, pregnancy-related and infant factors, 5-month feeding modality was not significantly associated with postpartum weight change: weight change by 24 months postpartum, compared to the change in the reference EBF group, was 0.03 kg in NBF (95% CI: ?2.5 to +2.5 kg; P = 0.90) and 0.1 kg in MF (95% CI: ?3.0 to +3.2 kg; P = 0.78).ConclusionHIV-infected and -uninfected women experienced similar weight loss over 24 months. Weight change postpartum was not associated with 5-month breastfeeding modality among HIV-infected and -uninfected women.ObjectifDéterminer l'effet des pratiques d'alimentation des nourrissons sur la variation du poids postpartum chez les femmes infectées et non infectées par le VIH en Afrique du Sud.MéthodesDans une étude de cohorte d'intervention non randomisée sur la thérapie aux antirétroviraux, les nourrissons de femmes naïves pour le traitement en Afrique du Sud, ont été classés comme allaités exclusivement au sein (EBF), recevant une alimentation mixte (MF) ou non allaités au sein (NBF), à chaque visite. Nous avons analysé l'alimentation du nourrisson cumulativement de la naissance à cinq mois, en utilisant l'historique de l'alimentation sur 24 heures (recueillies hebdomadairement pour chacun des sept jours précédents). En utilisant l’équation d'estimation des modèles mixtes généralisés, permettant des mesures répétées, nous avons comparé les changements de poids (kg) postpartum de la première mesure du poids postpartum de la mère endéans les six premières semaines (poids de base) au poids à chaque visite subséquente durant 24 mois chez 2340 femmes infectées et non infectées par le VIH, ayant eu des naissances vivantes et au moins deux mesures du poids postpartum.RésultatsLa perte de poids des femmes infectées (-0,2 kg; IC: -1,7 à 1,3 kg; P = 0,81) et non infectées (0,5 kg, IC95%: -2,1 à 1,2 kg; P = 0,58) par le VIH était marginalement non significative de la base à 24 mois postpartum. En ajustant pour le statut VIH et sociodémographique, pour les facteurs liés à la grossesse et infantiles, le mode d'alimentation sur cinq mois n’étaient pas significativement associé à la variation du poids postpartum; la variation de poids sur 24 mois postpartum comparée à celle dans le groupe EBF de référence, était de 0,03 kg chez les NBF (IC95%: -2,5 à 2,5 kg; P = 0,90) et 0,1 kg chez les MF (IC95%: -3,0 à 3,2 kg; P = 0,78).ConclusionLes femmes infectées et non infectées par le VIH connaissent une perte de poids similaire sur 24 mois. La variation du poids postpartum n'a pas été associée au mode d'allaitement à cinq mois chez les femmes infectées et non infectées par le VIH.ObjetivoDeterminar el efecto de las prácticas de alimentación de los bebés en la variación del peso materno postparto entre mujeres infectadas y no infectadas con VIH en Sudáfrica.MétodosEn una intervención en Sudáfrica no aleatorizada, dentro de un estudio de cohortes de mujeres que no habían recibido anteriormente terapia antirretroviral (naive) – los bebés de se clasificaron como recibiendo exclusivamente el pecho (EP), alimentación mixta (AM), o que no eran amamantados (NA) en cada visita. Hemos analizado la alimentación acumulativa del bebé, desde el nacimiento hasta los cinco meses de edad, utilizando un historial de alimentación de 24 horas (recogido semanalmente para los 7 días anteriores). Utilizando modelos mixtos de ecuaciones de estimación generalizadas, permitiendo medidas repetidas, hemos comparado el cambio de peso (kg) durante el postparto - desde la primera pesada dentro de las primeras seis semanas postparto (peso inicial) con cada visita subsiguiente, durante los 24 meses posteriores, para 2340 mujeres - infectadas con VIH y sin infectar – que dieron a luz bebés nacidos vivos y que tenían recogidas al menos dos pesadas postparto.ResultadosLas mujeres infectadas con VIH (-0.2 kg IC: -1.7 – 1.3 kg; P = 0.81) y aquellas no infectadas (-0.5kg; 95% IC: -2.1 – 1.2 kg; P =0.58) tenían una pérdida de peso marginal y no significativa entre el comienzo del estudio hasta los 24 meses después del parto. Ajustando para el estatus de VIH, los factores sociodemográficos y relacionados con el embarazo y el bebé, la modalidad de alimentación del bebé durante sus cinco primeros meses no estaba significativamente asociada con el cambio de peso postparto: el cambio de peso 24 meses después del parto, comparada con el cambio en referencia al grupo EP, era de 0.03 kg en NA (IC 95%: -2.5 – +2.5 kg; P = 0.90) y 0.1 kg en AM (IC 95%: -3.0 – +3.2 kg; P = 0.78).ConclusiónLas mujeres infectadas con VIH y aquellas sin infección experimentaron una pérdida de peso similar en los 24 meses postparto. El cambio de peso no estaba asociado con la modalidad de amamantamiento entre las mujeres VIH positivas y VIH negativas
Hamara Healthy Living Centre - an evaluation
Hamara is a Healthy Living Centre which aims to improve health and well-being through providing a range of culturally appropriate activities and services. Hamara has a vision of 'bringing communities together' and since it was established in 2004, the Centre has provided a valuable community resource in South Leeds. Partnership work between Hamara and Leeds Met goes back to 2002. In 2007, the Centre for Health Promotion Research carried out an evaluation of Hamara in partnership with Hamara staff and Leeds Met Community Partnerships and Volunteering. This was followed by a highly successful community cohesion conference 'One Community' which was held at Hamara on 10th October 2008, and was supported through a Leeds Met public engagement grant. The event attracted over a hundred people from diverse communities and organisations across Leeds. A packed audience heard Hilary Benn, local MP and Patron of Hamara, talk about the importance of working in collaboration around community cohesion. Jane South, Centre for Health Promotion Research, presented the main evaluation results and set out the some challenges for the future. The proceedings concluded with the presentation of awards to a number of for local community champions who work to bring people together and make a real difference in the city of Leeds
Dynamics of a disordered, driven zero range process in one dimension
We study a driven zero range process which models a closed system of
attractive particles that hop with site-dependent rates and whose steady state
shows a condensation transition with increasing density. We characterise the
dynamical properties of the mass fluctuations in the steady state in one
dimension both analytically and numerically and show that the transport
properties are anomalous in certain regions of the density-disorder plane. We
also determine the form of the scaling function which describes the growth of
the condensate as a function of time, starting from a uniform density
distribution.Comment: Revtex4, 5 pages including 2 figures; Revised version; To appear in
Phys. Rev. Let
Linking outcrop analogue with flow simulation to reduce uncertainty in sub-surface carbon capture and storage: an example from the Sherwood Sandstone Group of the Wessex Basin, UK
Modelling the behaviour of carbon dioxide (CO2) injected into sub-surface reservoirs as part of carbon capture and storage (CCS) strategies is often performed using models that incorporate very limited geological detail, particularly at the subseismic (metre to decametre) scale. Those modelling studies that incorporate varying degrees of geological realism show the inherent risks and uncertainties that can result from neglecting heterogeneity and reservoir–caprock topography along the migration path of an injected CO2 plume. A key problem is that detailed geological data are often not available for the relatively deep saline aquifers that are an important target for CCS. Deep saline aquifers fall between the relatively data-rich environments of shallow freshwater aquifers and hydrocarbon reservoirs and it is in these settings that outcrop analogues may play an important part in reducing the risks and uncertainties associated with CCS. This study uses an example from the Sherwood Sandstone Group (Otter Sandstone Formation) of the Wessex Basin to show how an outcrop study can impart a much greater understanding of heterogeneity in critical reservoir–caprock zones. Here the transition from the Sherwood Sandstone Group (fluvial sandstone reservoir) to the Mercia Mudstone Group (playa lacustrine mudstone seal) is not simple, but includes a major change in fluvial style that introduces considerable heterogeneity at the top of the reservoir. The study shows how laser-scanned outcrop can be used to rapidly construct static geological models that are taken through to flow simulations. In combination, the use of appropriate outcrop analogues and flow modelling can reduce the risks and uncertainties associated with CCS
Gamma Group-The Pale Horse: A proposal in response to a commercial air transportation study ort study
A conventional remotely piloted vehicle (RPV) was designed to operate in a fictional 'Aeroworld' as a 30 passenger aircraft. The topics addressed include: economic/cost analysis, aerodynamics, weight and structures, propulsion, stability and control, and performance
Mifepristone reduces insulin resistance in patient volunteers with adrenal incidentalomas that secrete low levels of cortisol : a pilot study
Background: Incidental adrenal masses are commonly detected during imaging for other pathologies. 10% of the elderly
population has an ‘adrenal incidentaloma’, up to 20% of these show low-grade autonomous cortisol secretion and 60% of
patients with autonomous cortisol secretion have insulin resistance. Cortisol excess is known to cause insulin resistance, an
independent cardiovascular risk marker, however in patients with adrenal incidentalomas it is unknown whether their
insulin resistance is secondary to the excess cortisol and therefore potentially reversible. In a proof of concept study we
examined the short-term effects of glucocorticoid receptor (GR) antagonism in patients with an adrenal incidentaloma to
determine whether their insulin resistance was reversible.
Methodology/Principal Findings: In a prospective open-label pilot study, six individuals with adrenal incidentalomas and
autonomous cortisol secretion were treated with mifepristone (a GR antagonist) 200 mg twice daily and studied for 4 weeks
on a Clinical Research Facility. Insulin resistance at four weeks was assessed by insulin resistance indices, lnHOMA-IR and
lnMatsuda, and AUC insulin during a 2-hour glucose tolerance test. Biochemical evidence of GR blockade was shown in all
individuals and across the group there was a significant reduction in insulin resistance: lnHOMA-IR (1.0vs0.6; p = 0.03),
lnHOMA-%beta (4.8vs4.3; p = 0.03) and lnMatsuda (1.2vs1.6; p = 0.03). Five out of six individuals showed a reduction in
insulin AUC .7237 pmol/l.min, and in two patients this showed a clinically significant cardiovascular benefit (as defined by
the Helsinki heart study).
Conclusions: Short-term GR antagonism is sufficient to reduce insulin resistance in some individuals with adrenal
incidentalomas and mild cortisol excess. Further assessment is required to assess if the responses may be used to stratify
therapy as adrenal incidentalomas may be a common remediable cause of increased cardiovascular risk
Square Patterns and Quasi-patterns in Weakly Damped Faraday Waves
Pattern formation in parametric surface waves is studied in the limit of weak
viscous dissipation. A set of quasi-potential equations (QPEs) is introduced
that admits a closed representation in terms of surface variables alone. A
multiscale expansion of the QPEs reveals the importance of triad resonant
interactions, and the saturating effect of the driving force leading to a
gradient amplitude equation. Minimization of the associated Lyapunov function
yields standing wave patterns of square symmetry for capillary waves, and
hexagonal patterns and a sequence of quasi-patterns for mixed capillary-gravity
waves. Numerical integration of the QPEs reveals a quasi-pattern of eight-fold
symmetry in the range of parameters predicted by the multiscale expansion.Comment: RevTeX, 11 pages, 8 figure
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