302 research outputs found

    QED calculation of the n=1 and n=2 energy levels in He-like ions

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    We perform ab initio QED calculations of energy levels for the n=1n=1 and n=2n=2 states of He-like ions with the nuclear charge in the range Z=12Z = 12-100. The complete set of two-electron QED corrections is evaluated to all orders in the parameter \aZ. Uncalculated contributions to energy levels come through orders \alpha^3 (\aZ)^2, \alpha^2 (\aZ)^7, and higher. The calculation presented is the first treatment for excited states of He-like ions complete through order \alpha^2 (\aZ)^4. A significant improvement in accuracy of theoretical predictions is achieved, especially in the high-ZZ region.Comment: 23 pages, 5 figure

    Assessing the accuracy of quantitative molecular microbial profiling

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    This is the final version of the article. Available from MDPI via the DOI in this record.The application of high-throughput sequencing in profiling microbial communities is providing an unprecedented ability to investigate microbiomes. Such studies typically apply one of two methods: amplicon sequencing using PCR to target a conserved orthologous sequence (typically the 16S ribosomal RNA gene) or whole (meta)genome sequencing (WGS). Both methods have been used to catalog the microbial taxa present in a sample and quantify their respective abundances. However, a comparison of the inherent precision or bias of the different sequencing approaches has not been performed. We previously developed a metagenomic control material (MCM) to investigate error when performing different sequencing strategies. Amplicon sequencing using four different primer strategies and two 16S rRNA regions was examined (Roche 454 Junior) and compared to WGS (Illumina HiSeq). All sequencing methods generally performed comparably and in good agreement with organism specific digital PCR (dPCR); WGS notably demonstrated very high precision. Where discrepancies between relative abundances occurred they tended to differ by less than twofold. Our findings suggest that when alternative sequencing approaches are used for microbial molecular profiling they can perform with good reproducibility, but care should be taken when comparing small differences between distinct methods. This work provides a foundation for future work comparing relative differences between samples and the impact of extraction methods. We also highlight the value of control materials when conducting microbial profiling studies to benchmark methods and set appropriate thresholds.The authors acknowledge funding from the European Metrology Research Programme joint research project “INFECT MET” (http://infectmet.lgcgroup.com) (an EMRP project, jointly funded by the EMRP participating countries within EURAMET and the European Union) and the UK National Measurement System for funding of this work and for the support of Thomas Laver by the BBSRC Industrial Case Studentship award BB/H016120/1

    Cognitive, emotional and environmental mediators of early parenting in high risk families

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    The UK currently has the highest number of premature births (babies born before 37 weeks gestation age and below 2.5kg) in Europe affecting around 70,000 babies and their caregivers each year. Consequently many interventions have been created to support the development of the preterm newborn and minimise the complications of prematurity. Many of the interventions developed have been predominantly tactile and have almost exclusively focused upon their effect upon the baby and not, for example considered the effect that this type of intervention might have upon the parents; specifically the mother, when they are the ones who perform the therapy. In fact there is a severe lack of systematic studies investigating the latter. Hence, the aim of this thesis was to search for research-based evidence on the benefits of environmental support to both babies (e.g. increased weight gain or awake periods) and their mothers (e.g. higher perceptions of themselves as a mother) during hospital confinement and within the context of Neonatal Health Psychology (NNHP). For this reason, the main hypothesis investigated whether mothers’ cognitions and emotions; specifically Maternal Self-Efficacy, Self-Esteem and Attachment, would be affected by environmental mediators in the form of structured or non-structured tactile sensory nurturing interventions. The empirical work reported in this thesis is divided into 3 distinct phases. Firstly, as their was no appropriate measure of maternal Self-Efficacy for mothers of hospitalised preterm neonates the main aim of Phase-1 was to develop and validate an appropriate measure. Using a prospective survey method and a mixed design (between/within and correlational) a total of 160 mother-preterm dyads (pooled from 2 cohorts; cohort 1, N=100; cohort 2, N=60) were recruited. The results demonstrated that the Perceived Maternal Parenting Self-Efficacy (PMPS-E) tool had good initial psychometric properties (including internal/external reliability and construct validity) for its use with mothers of relatively healthy hospitalised preterm neonates. Secondly, in order to investigate mothers’ perceived maternal parenting self-efficacy beliefs further Phase-2 examined whether the type of feeding a mother chose to give to her baby mediated her self-efficacy beliefs. The results suggested that breastfeeding a preterm neonate during hospital confinement may adversely affect mothers’ perceptions of their efficacy in all aspects of parenting. Finally, using an experimental method Phase-3 tested the main hypothesis of this thesis and used a randomised cluster control trial (RCCT) design to allocate 60 mothers and their preterms equally to one of three cluster groups; consisting of either structured (e.g. TAC-TIC therapy or Using a Toy) or non-structured (Placebo/Control) tactile sensory nurturing interventions. The main findings illustrate that tactile sensory nurturing interventions do mediate maternal cognitions and emotions, preterm weight gain and behavioural state. In particular, mothers who performed TAC-TIC demonstrated significantly higher self-reported perceptions in their self-efficacy, self-esteem and attachment, which was attributed to the fact that these babies spent increased amounts of time in an alert and responsive behavioural state, and gained more weight throughout the study period. Thus, the work presented throughout this thesis has implications for Neonatal Health Psychologists and other Health Care professionals’ practice within neonatal units, the use of Neonatal Health Psychology as a framework to study the preterm neonate and their family, and also the way in which both mothers and their hospitalised preterm neonates are supported during hospital confinement.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    A randomised trial of granulocyte-macrophage colony-stimulating factor for neonatal sepsis: outcomes at 2 years

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    The authors performed a randomised trial in very preterm small-for-gestational age (SGA) babies to determine if prophylaxis with granulocyte-macrophage colony-stimulating factor (GM-CSF) improves outcomes (the PROGRAMS trial). Despite increased neutrophil counts following GM-CSF, the authors reported no significant difference in neonatal sepsis-free survival

    Perinatal and maternal outcomes in planned home and obstetric unit births in women at ‘higher risk’ of complications: secondary analysis of the Birthplace national prospective cohort study

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    Objective: To explore and compare perinatal and maternal outcomes in women at ‘higher risk’ of complications planning home versus obstetric unit (OU) birth. Design: Prospective cohort study. Setting: OUs and planned home births in England. Population: 8180 ‘higher risk’ women in the Birthplace cohort. Methods: We used Poisson regression to calculate relative risks adjusted for maternal characteristics. Sensitivity analyses explored possible effects of differences in risk between groups and alternative outcome measures. Main outcome measures: Composite perinatal outcome measure encompassing ‘intrapartum related mortality and morbidity’ (intrapartum stillbirth, early neonatal death, neonatal encephalopathy, meconium aspiration syndrome, brachial plexus injury, fractured humerus or clavicle) and neonatal admission within 48 hours for more than 48 hours. Two composite maternal outcome measures capturing intrapartum interventions/adverse maternal outcomes and straightforward birth. Results: The risk of ‘intrapartum related mortality and morbidity’ or neonatal admission for more than 48 hours was lower in planned home births than planned OU births [adjusted relative risks (RR) 0.50, 95% CI 0.31–0.81]. Adjustment for clinical risk factors did not materially affect this finding. The direction of effect was reversed for the more restricted outcome measure ‘intrapartum related mortality and morbidity’ (RR adjusted for parity 1.92, 95% CI 0.97–3.80). Maternal interventions were lower in planned home births. Conclusions: The babies of ‘higher risk’ women who plan birth in an OU appear more likely to be admitted to neonatal care than those whose mothers plan birth at home, but it is unclear if this reflects a real difference in morbidity. Rates of intrapartum related morbidity and mortality did not differ statistically significantly between settings at the 5% level but a larger study would be required to rule out a clinically important difference between the groups

    Needs assessment to strengthen capacity in water and sanitation research in Africa:experiences of the African SNOWS consortium

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    Despite its contribution to global disease burden, diarrhoeal disease is still a relatively neglected area for research funding, especially in low-income country settings. The SNOWS consortium (Scientists Networked for Outcomes from Water and Sanitation) is funded by the Wellcome Trust under an initiative to build the necessary research skills in Africa. This paper focuses on the research training needs of the consortium as identified during the first three years of the project
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