967 research outputs found
Audit incorporating avoidability and appropriate intervention can significantly decrease perinatal mortality
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
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
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
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
We consider the non-Abelian action for the dynamics of -branes in the
background of -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 branes in the 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 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 5-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
in the -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
We calculate the tension of -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 terms if is also taken to be
large. Furthermore using the finite prescription for the symmetrised trace
operation we anticipate the most general expression for the tension valid for
any . We find that even in this instance, corrections to the tension
scale as 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 and typos correcte
M-flation: Inflation From Matrix Valued Scalar Fields
We propose an inflationary scenario, M-flation, in which inflation is driven
by three hermitian matrices . The inflation
potential of our model, which is strongly motivated from string theory, is
constructed from and their commutators. We show that one can
consistently restrict the classical dynamics to a sector in which the
are proportional to the irreducible representations of SU(2). In
this sector our model effectively behaves as an N-flation model with
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 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
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
We use the non-Abelian DBI action to study the dynamics of coincident
-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 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 -brane world-volume
theory in the same generic background and find solutions consistent with energy
minimisation. In the 5-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 -string picture to leading order
suggesting that the action in the large 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
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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