955 research outputs found
The Probability Density of the Higgs Boson Mass
The LEP Collaborations have reported a small excess of events in their
combined Higgs boson analysis at center of mass energies up to about 208 GeV.
In this communication, I present the result of a calculation of the probability
distribution function of the Higgs boson mass which can be rigorously obtained
if the validity of the Standard Model is assumed. It arises from the
combination of the most recent set of precision electroweak data and the
current results of the Higgs searches at LEP 2.Comment: 3 pages, 2 figure
A simple formula for pooling knowledge about a quantum system
When various observers obtain information in an independent fashion about a
classical system, there is a simple rule which allows them to pool their
knowledge, and this requires only the states-of-knowledge of the respective
observers. Here we derive an equivalent quantum formula. While its realm of
applicability is necessarily more limited, it does apply to a large class of
measurements, and we show explicitly for a single qubit that it satisfies the
intuitive notions of what it means to pool knowledge about a quantum system.
This analysis also provides a physical interpretation for the trace of the
product of two density matrices.Comment: 5 pages, Revtex
Women's Perceptions of Contributory Factors for Not Achieving a Vaginal Birth After Cesarean (VBAC)
BACKGROUND: With cesarean rates around the world escalating, concern is growing around why women wanting a vaginal birth after cesarean (VBAC) are not achieving their goal. AIM: To gain an understanding of women’s perceptions of factors they felt contributed to not achieving a VBAC. SETTING AND PARTICIPANTS: Fifteen women were interviewed following a nonelective repeat cesarean section (NERCS). They had attended a Western Australian midwifery-led service, next birth after cesarean (NBAC), and labored but were not successful in achieving a VBAC because of reasons around delayed progress. Interview transcripts were analyzed using Colaizzi’s method of thematic analysis. FINDINGS: Five themes emerged: “Tentative commitment with lingering doubts,” “My body failed me,” “Compromised by a longer than tolerable labor,” “Unable to effectively self-advocate in a climate of power struggling and poor support,” and “The inflexibility of hospital processes.” The final theme included two subthemes: “Restrictive policies” on labor and use of the cardiotocography, “The CTG.” CONCLUSIONS: When labor did not progress as envisaged and hospital processes adversely affected how women were supported, women’s doubts around being able to achieve a VBAC were reinforced with a NERCS. Maternity services need to ensure clinical practice reflects best evidence while assuring staff are supportive of women’s choice
Fitting in a complex chi^2 landscape using an optimized hypersurface sampling
Fitting a data set with a parametrized model can be seen geometrically as
finding the global minimum of the chi^2 hypersurface, depending on a set of
parameters {P_i}. This is usually done using the Levenberg-Marquardt algorithm.
The main drawback of this algorithm is that despite of its fast convergence, it
can get stuck if the parameters are not initialized close to the final
solution. We propose a modification of the Metropolis algorithm introducing a
parameter step tuning that optimizes the sampling of parameter space. The
ability of the parameter tuning algorithm together with simulated annealing to
find the global chi^2 hypersurface minimum, jumping across chi^2{P_i} barriers
when necessary, is demonstrated with synthetic functions and with real data
What is the healthcare utilisation and out-of-pocket expenditure associated with osteoarthritis? A cross-sectional study.
OBJECTIVE: To examine the use and out-of-pocket expenses resulting from consultations, products and practices across conventional, self-care, and complementary medicine (CM) treatments for osteoarthritis (OA) among Australian women. DESIGN, SETTING AND PARTICIPANTS: A cross-sectional survey of 800 women from the 45 and Up Study who had reported a clinical diagnosis of OA. OUTCOME MEASURES: Women's use of conventional, CM and self-prescribed treatments for OA and the associated out-of-pocket cost. RESULTS: Completed questionnaires were returned by 403 women (50.4%). Their average time since the first diagnosis of OA was 15.4 years, and self-rated severity of OA was 5.1 (out of 10) over the past 12 months. During the previous year, 67.0% of the women consulted a doctor, 39.2% consulted an allied health practitioner and 34.7% consulted a CM practitioner for their OA. Some women (19%) consulted with practitioner(s) from all three practitioner groups, 27% consulted with practitioner(s) from two of the three practitioner groups, while 6% consulted with a CM practitioner only. Women with a greater time since diagnosis had more consultations, as did women who rated their OA as more severe. Women's average combined out-of-pocket expenditure for OA-related healthcare consultations, prescription medications, products, and practices was 873 million per annum. CONCLUSIONS: Australian women with OA use a range of conventional and CM consultations, self-care, products and practices to manage their condition, incurring significant out-of-pocket expenses. Given the high individual and societal burden of OA, there is a need for further research into the concurrent use of different healthcare resources with a view to providing safe, cost-effective management of OA across the healthcare system and the wider community
Toroidal magnetized iron neutrino detector for a neutrino factory
A neutrino factory has unparalleled physics reach for the discovery and measurement of CP violation in the neutrino sector. A far detector for a neutrino factory must have good charge identification with excellent background rejection and a large mass. An elegant solution is to construct a magnetized iron neutrino detector (MIND) along the lines of MINOS, where iron plates provide a toroidal magnetic field and scintillator planes provide 3D space points. In this paper, the current status of a simulation of a toroidal MIND for a neutrino factory is discussed in light of the recent measurements of large θ13. The response and performance using the 10 GeV neutrino factory configuration are presented. It is shown that this setup has equivalent δCP reach to a MIND with a dipole field and is sensitive to the discovery of CP violation over 85% of the values of δCP
Detection methods for non-Gaussian gravitational wave stochastic backgrounds
We address the issue of finding an optimal detection method for a
discontinuous or intermittent gravitational wave stochastic background. Such a
signal might sound something like popcorn popping. We derive an appropriate
version of the maximum likelihood detection statistic, and compare its
performance to that of the standard cross-correlation statistic both
analytically and with Monte Carlo simulations. The maximum likelihood statistic
performs better than the cross-correlation statistic when the background is
sufficiently non-Gaussian. For both ground and space based detectors, this
results in a gain factor, ranging roughly from 1 to 3, in the minimum
gravitational-wave energy density necessary for detection, depending on the
duty cycle of the background. Our analysis is exploratory, as we assume that
the time structure of the events cannot be resolved, and we assume white,
Gaussian noise in two collocated, aligned detectors. Before this detection
method can be used in practice with real detector data, further work is
required to generalize our analysis to accommodate separated, misaligned
detectors with realistic, colored, non-Gaussian noise.Comment: 25 pages, 12 figures, submitted to physical review D, added revisions
in response to reviewers comment
Bayesian analysis of exoplanet and binary orbits
We introduce BASE (Bayesian astrometric and spectroscopic exoplanet detection
and characterisation tool), a novel program for the combined or separate
Bayesian analysis of astrometric and radial-velocity measurements of potential
exoplanet hosts and binary stars. The capabilities of BASE are demonstrated
using all publicly available data of the binary Mizar A.Comment: Accepted for publication in Astronomy & Astrophysic
An Introduction to Data Analysis in Asteroseismology
A practical guide is presented to some of the main data analysis concepts and
techniques employed contemporarily in the asteroseismic study of stars
exhibiting solar-like oscillations. The subjects of digital signal processing
and spectral analysis are introduced first. These concern the acquisition of
continuous physical signals to be subsequently digitally analyzed. A number of
specific concepts and techniques relevant to asteroseismology are then
presented as we follow the typical workflow of the data analysis process,
namely, the extraction of global asteroseismic parameters and individual mode
parameters (also known as peak-bagging) from the oscillation spectrum.Comment: Lecture presented at the IVth Azores International Advanced School in
Space Sciences on "Asteroseismology and Exoplanets: Listening to the Stars
and Searching for New Worlds" (arXiv:1709.00645), which took place in Horta,
Azores Islands, Portugal in July 201
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