136 research outputs found

    Differential Very Long Baseline Interferometry (delta VLBI) spacecraft tracking system demonstration. Part 2: Data acquisition and processing

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    A set of experiments in the use of Differential Very Long Baseline Interferometry (delta VLBI) for spacecraft navigation were completed. Data using both Voyager spacecraft and a single quasar were acquired during the Jupiter encounter time period. The data were processed and analyzed to assess the navigation accuracy of delta VLBI. The data reduction and techniques for assessing data quality and consistency are discussed

    Alcohol use and sexual risk behaviour among men and women in inner-city Johannesburg, South Africa.

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    BACKGROUND: Alcohol misuse is a key factor underlying the remarkable vulnerability to HIV infection among men and women in sub-Saharan Africa, especially within urban settings. Its effects, however, vary by type of drinking, population group and are modified by socio-cultural co-factors. METHODS: We interviewed a random sample of 1465 men living in single-sex hostels and 1008 women in adjacent informal settlements in inner-city, Johannesburg, South Africa. Being drunk in the past week was used as an indicator of heavy episodic drinking, and frequency of drinking and number of alcohol units/week used as measures of volume. Associations between dimensions of alcohol use (current drinking, volume of alcohol consumed and heavy episodic drinking patterns) and sexual behaviours were assessed using multivariate logistic regression. RESULTS: Most participants were internal migrants from KwaZulu Natal province. About half of men were current drinkers, as were 13% of women. Of current male drinkers, 18% drank daily and 23% were drunk in the past week (women: 14% and 29% respectively). Among men, associations between heavy episodic drinking and sexual behaviour were especially pronounced. Compared with non-drinkers, episodic ones were 2.6 fold more likely to have transactional sex (95%CI = 1.7-4.1) and 2.2 fold more likely to have a concurrent partner (95%CI = 1.5-3.2). Alcohol use in men, regardless of measure, was strongly associated with having used physical force to have sex. Overall effects of alcohol on sexual behaviour were larger in women than men, and associations were detected between all alcohol measures in women, and concurrency, transactional sex and having been forced to have sex. CONCLUSIONS: Alcohol use and sexual behaviours are strongly linked among male and female migrant populations in inner-city Johannesburg. More rigorous interventions at both local and macro level are needed to alleviate alcohol harms and mitigate the alcohol-HIV nexus, especially among already vulnerable groups. These should target the specific dimensions of alcohol use that are harmful, assist women who drink to do so more safely and address the linkages between alcohol and sexual violence

    Need for timely paediatric HIV treatment within primary health care in rural South Africa

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    <p>Background: In areas where adult HIV prevalence has reached hyperendemic levels, many infants remain at risk of acquiring HIV infection. Timely access to care and treatment for HIV-infected infants and young children remains an important challenge. We explore the extent to which public sector roll-out has met the estimated need for paediatric treatment in a rural South African setting.</p> <p>Methods: Local facility and population-based data were used to compare the number of HIV infected children accessing HAART before 2008, with estimates of those in need of treatment from a deterministic modeling approach. The impact of programmatic improvements on estimated numbers of children in need of treatment was assessed in sensitivity analyses.</p> <p>Findings: In the primary health care programme of HIV treatment 346 children <16 years of age initiated HAART by 2008; 245(70.8%) were aged 10 years or younger, and only 2(<1%) under one year of age. Deterministic modeling predicted 2,561 HIV infected children aged 10 or younger to be alive within the area, of whom at least 521(20.3%) would have required immediate treatment. Were extended PMTCT uptake to reach 100% coverage, the annual number of infected infants could be reduced by 49.2%.</p> <p>Conclusion: Despite progress in delivering decentralized HIV services to a rural sub-district in South Africa, substantial unmet need for treatment remains. In a local setting, very few children were initiated on treatment under 1 year of age and steps have now been taken to successfully improve early diagnosis and referral of infected infants.</p&gt

    An investigation of factors associated with the health and well-being of HIV-infected or HIV-affected older people in rural South Africa

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    BackgroundDespite the severe impact of HIV in sub-Saharan Africa, the health of older people aged 50+ is often overlooked owing to the dearth of data on the direct and indirect effects of HIV on older people's health status and well-being. The aim of this study was to examine correlates of health and well-being of HIV-infected older people relative to HIV-affected people in rural South Africa, defined as participants with an HIV-infected or death of an adult child due to HIV-related cause. MethodsData were collected within the Africa Centre surveillance area using instruments adapted from the World Health Organization (WHO) Study on global AGEing and adult health (SAGE). A stratified random sample of 422 people aged 50+ participated. We compared the health correlates of HIV-infected to HIV-affected participants using ordered logistic regressions. Health status was measured using three instruments: disability index, quality of life and composite health score. ResultsMedian age of the sample was 60 years (range 50-94). Women HIV-infected (aOR 0.15, 95% confidence interval (CI) 0.08-0.29) and HIV-affected (aOR 0.20, 95% CI 0.08-0.50), were significantly less likely than men to be in good functional ability. Women's adjusted odds of being in good overall health state were similarly lower than men's; while income and household wealth status were stronger correlates of quality of life. HIV-infected participants reported better functional ability, quality of life and overall health state than HIV-affected participants. Discussion and Conclusions The enhanced healthcare received as part of anti-retroviral treatment as well as the considerable resources devoted to HIV care appear to benefit the overall well-being of HIV-infected older people; whereas similar resources have not been devoted to the general health needs of HIV uninfected older people. Given increasing numbers of older people, policy and programme interventions are urgently needed to holistically meet the health and well-being needs of older people beyond the HIV-related care system. <br/

    Stroking modulates noxious-evoked brain activity in human infants

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    A subclass of C fibre sensory neurons found in hairy skin are activated by gentle touch [1] and respond optimally to stroking at ∼1–10 cm/s, serving a protective function by promoting affiliative behaviours. In adult humans, stimulation of these C-tactile (CT) afferents is pleasant, and can reduce pain perception [2]. Touch-based techniques, such as infant massage and kangaroo care, are designed to comfort infants during procedures, and a modest reduction in pain-related behavioural and physiological responses has been observed in some studies [3]. Here, we investigated whether touch can reduce noxious-evoked brain activity. We demonstrate that stroking (at 3 cm/s) prior to an experimental noxious stimulus or clinical heel lance can attenuate noxious-evoked brain activity in infants. CT fibres may represent a biological target for non-pharmacological interventions that modulate pain in early life

    A blinded randomised placebo-controlled trial investigating the efficacy of morphine analgesia for procedural pain in infants: Trial protocol [version 1; peer review: 2 approved, 1 approved with reservations]

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    Infant pain has both immediate and long-term negative consequences, yet in clinical practice it is often undertreated. To date, few pain-relieving drugs have been tested in infants. Morphine is a potent analgesic that provides effective pain relief in adults, but there is inconclusive evidence for its effectiveness in infants. The purpose of this study is to establish whether oral morphine provides effective analgesia for procedural pain in infants. // A blinded, placebo-controlled, parallel-group randomized, phase II, clinical trial will be undertaken to determine whether morphine sulphate administered orally prior to clinically-required retinopathy of prematurity (ROP) screening and heel lancing provides effective analgesia. 156 infants between 34 and 42 weeks’ gestational age who require a clinical heel lance and ROP screening on the same test occasion will be included in the trial. Infants will be randomised to receive either a single dose of morphine sulphate (100 μg/kg) or placebo. Each infant will be monitored for 48 hours and safety data will be collected during the 24 hours following drug administration. // The primary outcome will be the Premature Infant Pain Profile–revised (PIPP-R) score 30 seconds after ROP screening. The co-primary outcome will be the magnitude of nociceptive-specific brain activity evoked by a clinically-required heel lance. Infant clinical stability will be assessed by comparing the number of episodes of bradycardia, tachycardia, desaturation and apnoea, and changes in respiratory support requirements in the 24-hour periods before and after the clinical intervention. In addition, drug safety will be assessed by considering the occurrence of apnoeic and hypotensive episodes requiring intervention in the 24-hour period following drug administration. This study has been published as an Accepted Protocol Summary by The Lancet

    fMRI reveals neural activity overlap between adult and infant pain

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    Limited understanding of infant pain has led to its lack of recognition in clinical practice. While the network of brain regions that encode the affective and sensory aspects of adult pain are well described, the brain structures involved in infant nociceptive processing are less well known, meaning little can be inferred about the nature of the infant pain experience. Using fMRI we identified the network of brain regions that are active following acute noxious stimulation in newborn infants, and compared the activity to that observed in adults. Significant infant brain activity was observed in 18 of the 20 active adult brain regions but not in the infant amygdala or orbitofrontal cortex. Brain regions that encode sensory and affective components of pain are active in infants, suggesting that the infant pain experience closely resembles that seen in adults. This highlights the importance of developing effective pain management strategies in this vulnerable population

    Evidence-based intervention for preschool children with primary speech and language impairments: Child Talk - an exploratory mixed-methods study

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    BackgroundThe Child Talk study aimed to develop an evidence-based framework to support the decision-making of speech and language therapists (SLTs) as they design and plan interventions appropriate to the needs of individual children with primary speech and language impairments and their families. The need for early identification and effective intervention for these children continues to be a government policy priority because of the link between children’s early speech and language skills and their broader well-being and outcomes in later life. The first phase of Child Talk sought to map and describe current SLT practice for these children; identify and summarise the existing research evidence relating to practice; and investigate the perspectives of parents, early years practitioners, preschool children and ‘underserved’ communities on speech and language therapy. The second phase of Child Talk focused on the development of a toolkit – assessment tools, outcome measures and a data set – to support future service and economic evaluations of the framework.MethodsChild Talk adopted a mixed-methods design. Quantitative methods included surveys and investigated the prevalence and patterns of intervention usage; qualitative data collection methods included focus groups, interviews and reflection to investigate participants’ perspectives and understandings of interventions. Data analysis methods included descriptive and inferential statistics, thematic and content analysis and framework analysis. Participants were recruited nationally through six NHS sites, professional bodies, parent groups and advertising. Participants included SLTs (n = 677), parents (n = 84), preschool children (n = 24), early years practitioners (n = 31) and ‘underserved’ communities (n = 52).Key findingsSpeech and language therapy interventions were characterised in terms of nine themes, viewed as comprehensive and inclusive by practitioners. Relevant assessments, interventions and outcome domains were identified for the nine themes. Areas of tacit knowledge and underspecified processes contributed to variability in the detail of the framework. Systematic reviews identified 58 relevant and robust studies (from 55,271 papers retrieved from the initial literature search). The number of studies relevant to each theme varied from 1 to 33. Observational data on preschool children’s perspectives on speech and language therapy interventions revealed the dynamic nature of their interaction with different activities and people within therapy sessions. Parents’ experiences of speech and language therapy were generally positive although some reported that the rationale for therapy was not always clear. Parental perspectives in underserved communities suggested that, although parents were confident about how to support children’s language development, they were less informed about the nature of language impairments and the function of speech and language therapy. The availability of information regarding resources directed towards speech and language therapy services was poor. In particular, services lacked both a culture of collecting outcome data routinely and measures of professional input and costs associated with their activities.ConclusionA descriptive framework of SLT practice has been developed to support the discussions between therapists and families when making decisions regarding the selection of interventions and outcome measures. Further research is needed to address gaps in the intervention framework and evaluate its effectiveness and cost-effectiveness in improving outcomes for preschool children with primary speech and language impairments.Study registrationThis study is registered as PROSPERO CRD42013006369
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