967 research outputs found

    Audit incorporating avoidability and appropriate intervention can significantly decrease perinatal mortality

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    Objective. To evaluate the role of the ICA (Identification, Cause, Avoidable factor) Solution method of perinatal audit in reducing perinatal mortality.Design. Retrospective audit of 1 060 perinatal deaths between 1 January 1991 and 31 December 1992.Setting. Livingstone Hospital Maternity Service.Subjects. One thousand and sixty perinatal deaths, where the gestational age exceeded 28 weeks or, when gestational age was unknown, the birth weight was equal to or exceeded 1 000 g.Main outcome measures. All perinatal deaths were identified and classified by primary obstetric cause for perinatal loss. In the second year of the study avoidable factors were sought and, if found, graded and categorised.Results. The major primary obstetric causes of perinatal loss identified and amenable to intervention were intrapartum trauma, intrapartum asphyxia and infection. In the second year of study potentially avoidable factors were sought and identified in almost 50% of perinatal deaths. Appropriate intervention lowered the perinatal mortality rate by 23% (P < 0,05; odds ratio 0,76; 95% confidence interval 0,67 - 0,86).Conclusion. The ICA Solution method of perinatal audit identified problems in overall obstetric care, facilitating a significant fall in perinatal mortality

    Persistent socioeconomic and racial and ethnic disparities in pathogen burden in the United States, 1999-2014

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    The disproportionate burden of prevalent, persistent pathogens among disadvantaged groups may contribute to socioeconomic and racial/ethnic disparities in long-term health. We assessed if the social patterning of pathogen burden changed over 16 years in a U.S.-representative sample. Data came from 17 660 National Health and Nutrition Examination Survey participants. Pathogen burden was quantified by summing the number of positive serologies for cytomegalovirus, herpes simplex virus-1, HSV-2, human papillomavirus and Toxoplasma gondii and dividing by the number of pathogens tested, giving a percent-seropositive for each participant. We examined sex- and age-adjusted mean pathogen burdens from 1999-2014, stratified by race/ethnicity and SES (poverty-to-income ratio (PIR); educational attainment). Those with a PIR 3.5, with no change over time. Educational disparities were even greater and showed some evidence of increasing over time, with the mean pathogen burden among those with less than a high school education approximately twice that of those who completed more than high school. Non-Hispanic Black, Mexican American and other Hispanic participants had a mean pathogen burden 1.3-1.9 times non-Hispanic Whites. We demonstrate that socioeconomic and racial/ethnic disparities in pathogen burden have persisted across 16 years, with little evidence that the gap is closing

    Demonstration of Elemental Partitioning During Austenite Formation in Low-Carbon Aluminium alloyed steel

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    This work investigates the influence of aluminium, in solid solution, on austenite formation in a lowcarbon aluminium alloyed (0.48 wt. %) steel during continuous heating. A thin section across an untransformed ferrite and austenite interface was prepared for transmission electron microscopy by focused ion beam milling. Microstructural characterization using imaging and elemental analysis demonstrates that aluminium partitions from austenite to ferrite during very slow heating conditions, stabilizing this latter phase and shifting the final transformation temperature for austenite formation (Ac3)Peer reviewe

    Demonstration of Elemental Partitioning During Austenite Formation in Low-Carbon Aluminium alloyed steel

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    This work investigates the influence of aluminium, in solid solution, on austenite formation in a lowcarbon aluminium alloyed (0.48 wt. %) steel during continuous heating. A thin section across an untransformed ferrite and austenite interface was prepared for transmission electron microscopy by focused ion beam milling. Microstructural characterization using imaging and elemental analysis demonstrates that aluminium partitions from austenite to ferrite during very slow heating conditions, stabilizing this latter phase and shifting the final transformation temperature for austenite formation (Ac3)Peer reviewe

    Fuzzy Sphere Dynamics and Non-Abelian DBI in Curved Backgrounds

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    We consider the non-Abelian action for the dynamics of NDp′N Dp'-branes in the background of MDpM Dp-branes, which parameterises a fuzzy sphere using the SU(2) algebra. We find that the curved background leads to collapsing solutions for the fuzzy sphere except when we have D0D0 branes in the D6D6 background, which is a realisation of the gravitational Myers effect. Furthermore we find the equations of motion in the Abelian and non-Abelian theories are identical in the large NN limit. By picking a specific ansatz we find that we can incorporate angular momentum into the action, although this imposes restriction upon the dimensionality of the background solutions. We also consider the case of non-Abelian non-BPS branes, and examine the resultant dynamics using world-volume symmetry transformations. We find that the fuzzy sphere always collapses but the solutions are sensitive to the combination of the two conserved charges and we can find expanding solutions with turning points. We go on to consider the coincident NSNS5-brane background, and again construct the non-Abelian theory for both BPS and non-BPS branes. In the latter case we must use symmetry arguments to find additional conserved charges on the world-volumes to solve the equations of motion. We find that in the Non-BPS case there is a turning solution for specific regions of the tachyon and radion fields. Finally we investigate the more general dynamics of fuzzy S2k\mathbb{S}^{2k} in the DpDp-brane background, and find collapsing solutions in all cases.Comment: 49 pages, 3 figures, Latex; Version to appear in JHE

    Non-Abelian (p,q) Strings in the Warped Deformed Conifold

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    We calculate the tension of (p,q)(p,q)-strings in the warped deformed conifold using the non-Abelian DBI action. In the large flux limit, we find exact agreement with the recent expression obtained by Firouzjahi, Leblond and Henry-Tye up to and including order 1/M21/M^2 terms if qq is also taken to be large. Furthermore using the finite qq prescription for the symmetrised trace operation we anticipate the most general expression for the tension valid for any (p,q)(p,q). We find that even in this instance, corrections to the tension scale as 1/M21/M^2 which is not consistent with simple Casimir scaling.Comment: 18 pages, Latex, 1 figure; Added a discussion of the case when the warp factor parameter b≠1b\neq 1 and typos correcte

    M-flation: Inflation From Matrix Valued Scalar Fields

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    We propose an inflationary scenario, M-flation, in which inflation is driven by three N×NN\times N hermitian matrices Φi,i=1,2,3\Phi_i, i=1,2,3. The inflation potential of our model, which is strongly motivated from string theory, is constructed from Φi\Phi_{i} and their commutators. We show that one can consistently restrict the classical dynamics to a sector in which the Φi\Phi_i are proportional to the N×NN\times N irreducible representations of SU(2). In this sector our model effectively behaves as an N-flation model with 3N23 N^2 number of fields and the effective inflaton field has a super-Planckian field value. Furthermore, the fine-tunings associated with unnaturally small couplings in the chaotic type inflationary scenarios are removed. Due to the matrix nature of the inflaton fields there are 3N2−13N^2-1 extra scalar fields in the dynamics. These have the observational effects such as production of iso-curvature perturbations on cosmic microwave background. Moreover, the existence of these extra scalars provides us with a natural preheating mechanism and exit from inflation. As the effective inflaton field can traverse super-Planckian distances in the field space, the model is capable of producing a considerable amount of gravity waves that can be probed by future CMB polarization experiments such as PLANCK, QUIET and CMBPOL.Comment: minor changes, the counting of the alpha and beta modes are corrected, references adde

    A Comparison of Solar Cycle Variations in the Equatorial Rotation Rates of the Sun's Subsurface, Surface, Corona, and Sunspot Groups

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    Using the Solar Optical Observing Network (SOON) sunspot-group data for the period 1985-2010, the variations in the annual mean equatorial-rotation rates of the sunspot groups are determined and compared with the known variations in the solar equatorial-rotation rates determined from the following data: i) the plasma rotation rates at 0.94Rsun, 0.95Rsun,...,1.0Rsun measured by Global Oscillation Network Group (GONG) during the period 1995-2010, ii) the data on the soft X-ray corona determined from Yohkoh/SXT full disk images for the years 1992-2001, iii) the data on small bright coronal structures (SBCS) which were traced in Solar and Heliospheric Observatory (SOHO)/EIT images during the period 1998-2006, and iv) the Mount Wilson Doppler-velocity measurements during the period 1986-2007. A large portion (up to approximate 30 deg latitude) of the mean differential-rotation profile of the sunspot groups lies between those of the internal differential-rotation rates at 0.94Rsun and 0.98Rsun.The variation in the yearly mean equatorial-rotation rate of the sunspot groups seems to be lagging that of the equatorial-rotation rate determined from the GONG measurements by one to two years.The amplitude of the latter is very small.The solar-cycle variation in the equatorial-rotation rate of the solar corona closely matches that determined from the sunspot-group data.The variation in the equatorial-rotation rate determined from the Mount Wilson Doppler-velocity data closely resembles the corresponding variation in the equatorial-rotation rate determined from the sunspot-group data that included the values of the abnormal angular motions (> 3 deg per day) of the sunspot groups. Implications of these results are pointed out.Comment: 22 pages, 10 figures, accepted by Solar Physic

    Electrified Fuzzy Spheres and Funnels in Curved Backgrounds

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    We use the non-Abelian DBI action to study the dynamics of NN coincident DpDp-branes in an arbitrary curved background, with the presence of a homogenous world-volume electric field. The solutions are natural extensions of those without electric fields, and imply that the spheres will collapse toward zero size. We then go on to consider the D1−D3D1-D3 intersection in a curved background and find various dualities and automorphisms of the general equations of motion. It is possible to map the dynamical equation of motion to the static one via Wick rotation, however the additional spatial dependence of the metric prevents this mapping from being invertible. Instead we find that a double Wick rotation leaves the static equation invariant. This is very different from the behaviour in Minkowski space. We go on to construct the most general static fuzzy funnel solutions for an arbitrary metric either by solving the static equations of motion, or by finding configurations which minimise the energy. As a consistency check we construct the Abelian D3D3-brane world-volume theory in the same generic background and find solutions consistent with energy minimisation. In the NSNS5-brane background we find time dependent solutions to the equations of motion, representing a time dependent fuzzy funnel. These solutions match those obtained from the DD-string picture to leading order suggesting that the action in the large NN limit does not need corrections. We conclude by generalising our solutions to higher dimensional fuzzy funnels.Comment: 38 pages, Latex; references adde

    Tumour profiling tests to guide adjuvant chemotherapy decisions in early breast cancer: a systematic review and economic analysis

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    Background Breast cancer and its treatment can have an impact on health-related quality of life and survival. Tumour profiling tests aim to identify whether or not women need chemotherapy owing to their risk of relapse. Objectives To conduct a systematic review of the effectiveness and cost-effectiveness of the tumour profiling tests oncotype DX® (Genomic Health, Inc., Redwood City, CA, USA), MammaPrint® (Agendia, Inc., Amsterdam, the Netherlands), Prosigna® (NanoString Technologies, Inc., Seattle, WA, USA), EndoPredict® (Myriad Genetics Ltd, London, UK) and immunohistochemistry 4 (IHC4). To develop a health economic model to assess the cost-effectiveness of these tests compared with clinical tools to guide the use of adjuvant chemotherapy in early-stage breast cancer from the perspective of the NHS and Personal Social Services. Design A systematic review and health economic analysis were conducted. Review methods The systematic review was partially an update of a 2013 review. Nine databases were searched in February 2017. The review included studies assessing clinical effectiveness in people with oestrogen receptor-positive, human epidermal growth factor receptor 2-negative, stage I or II cancer with zero to three positive lymph nodes. The economic analysis included a review of existing analyses and the development of a de novo model. Results A total of 153 studies were identified. Only one completed randomised controlled trial (RCT) using a tumour profiling test in clinical practice was identified: Microarray In Node-negative Disease may Avoid ChemoTherapy (MINDACT) for MammaPrint. Other studies suggest that all the tests can provide information on the risk of relapse; however, results were more varied in lymph node-positive (LN+) patients than in lymph node-negative (LN0) patients. There is limited and varying evidence that oncotype DX and MammaPrint can predict benefit from chemotherapy. The net change in the percentage of patients with a chemotherapy recommendation or decision pre/post test ranged from an increase of 1% to a decrease of 23% among UK studies and a decrease of 0% to 64% across European studies. The health economic analysis suggests that the incremental cost-effectiveness ratios for the tests versus current practice are broadly favourable for the following scenarios: (1) oncotype DX, for the LN0 subgroup with a Nottingham Prognostic Index (NPI) of > 3.4 and the one to three positive lymph nodes (LN1–3) subgroup (if a predictive benefit is assumed); (2) IHC4 plus clinical factors (IHC4+C), for all patient subgroups; (3) Prosigna, for the LN0 subgroup with a NPI of > 3.4 and the LN1–3 subgroup; (4) EndoPredict Clinical, for the LN1–3 subgroup only; and (5) MammaPrint, for no subgroups. Limitations There was only one completed RCT using a tumour profiling test in clinical practice. Except for oncotype DX in the LN0 group with a NPI score of > 3.4 (clinical intermediate risk), evidence surrounding pre- and post-test chemotherapy probabilities is subject to considerable uncertainty. There is uncertainty regarding whether or not oncotype DX and MammaPrint are predictive of chemotherapy benefit. The MammaPrint analysis uses a different data source to the other four tests. The Translational substudy of the Arimidex, Tamoxifen, Alone or in Combination (TransATAC) study (used in the economic modelling) has a number of limitations. Conclusions The review suggests that all the tests can provide prognostic information on the risk of relapse; results were more varied in LN+ patients than in LN0 patients. There is limited and varying evidence that oncotype DX and MammaPrint are predictive of chemotherapy benefit. Health economic analyses indicate that some tests may have a favourable cost-effectiveness profile for certain patient subgroups; all estimates are subject to uncertainty. More evidence is needed on the prediction of chemotherapy benefit, long-term impacts and changes in UK pre-/post-chemotherapy decisions. Study registration This study is registered as PROSPERO CRD42017059561. Funding The National Institute for Health Research Health Technology Assessment programme
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