3,293 research outputs found
Efficient and Inefficient Composites in the U.S. Domestic Property–Casualty Insurance Industry
Peter M. Ellis, Ph.D., is a professor of management at Utah State University, Logan, UT, 84322-3510
Constraints on Inflationary Solutions in the Presence of Shear and Bulk Viscosity
Inflationary models and their claim to solve many of the outstanding problems
in cosmology have been the subject of a great deal of debate over the last few
years. A major sticking point has been the lack of both good observational and
theoretical arguments to single out one particular model out of the many that
solve these problems. Here we examine the degree of restrictiveness on the
dynamical relationship between the cosmological scale factor and the inflation
driving self-interaction potential of a minimally coupled scalar field, imposed
by the condition that the scalar field is required to be real during a
classical regime (the reality condition). We systema\-tically look at the
effects of this constraint on many of the inflationary models found in the
literature within the FLRW framework, and also look at what happens when
physically motivated perturbations such as shear and bulk viscosity are
introduced. We find that in many cases, either the models are totally excluded
or the reality condition gives rise to constraints on the scale factor and on
the various parameters of the model.Comment: 21 pages, LaTe
Is progression-free survival associated with a better health-related quality of life in patients with lung cancer? : Evidence from two randomised trials with afatinib
Acknowledgements Medical writing assistance, supported financially by Boehringer Ingelheim, was provided by Suzanne Patel during the preparation of this article. Funding This study was supported by Boehringer Ingelheim.Peer reviewedPublisher PD
Singlet superfield extension of the minimal supersymmetric standard model with Peccei-Quinn symmetry and a light pseudoscalar Higgs boson at the LHC
Motivated by the mu-problem and the axion solution to the strong CP-problem,
we extend the MSSM with one more chiral singlet field . The underlying
PQ-symmetry allows only one more term in the superpotential. The
spectrum of the Higgs system includes a light pseudoscalar (in addition
to the standard CP-even Higgs boson), predominantly decaying to two photons:
. Both Higgs bosons might be in the range accessible to
current LHC experiments.Comment: 5 pages with 3 figure
The abstract boundary---a new approach to singularities of manifolds
A new scheme is proposed for dealing with the problem of singularities in
General Relativity. The proposal is, however, much more general than this. It
can be used to deal with manifolds of any dimension which are endowed with
nothing more than an affine connection, and requires a family \calc\ of curves
satisfying a {\em bounded parameter property} to be specified at the outset.
All affinely parametrised geodesics are usually included in this family, but
different choices of family \calc\ will in general lead to different
singularity structures. Our key notion is the {\em abstract boundary\/} or {\em
-boundary\/} of a manifold, which is defined for any manifold \calm\ and is
independent of both the affine connection and the chosen family \calc\ of
curves. The -boundary is made up of equivalence classes of boundary points
of \calm\ in all possible open embeddings. It is shown that for a
pseudo-Riemannian manifold (\calm,g) with a specified family \calc\ of
curves, the abstract boundary points can then be split up into four main
categories---regular, points at infinity, unapproachable points and
singularities. Precise definitions are also provided for the notions of a {\em
removable singularity} and a {\em directional singularity}. The
pseudo-Riemannian manifold will be said to be singularity-free if its abstract
boundary contains no singularities. The scheme passes a number of tests
required of any theory of singularities. For instance, it is shown that all
compact manifolds are singularity-free, irrespective of the metric and chosen
family \calc.Comment: 40 pages (amslatex) + 5 uuencoded figures (A postscript version is
also available on http://einstein.anu.edu.au/), CMA Maths. Research Report
No. MRR028-9
Challenges to Implementation of an Epidermal Growth Factor Receptor Testing Strategy for Non–Small-Cell Lung Cancer in a Publicly Funded Health Care System
Background:Data from seven recent randomized clinical trials have demonstrated that epidermal growth factor (EGFR) mutation status is predictive of improved progression-free survival and quality of life from first-line EGFR tyrosine kinase inhibitor therapy compared with platinum-based chemotherapy. We examined barriers to the initial implementation of a national EGFR testing policy in Canada.Methods:Five laboratories across Canada underwent a validation and quality-control exercise for EGFR mutation testing using reverse transcriptase–polymerase chain reaction with financial support from the pharmaceutical industry for the initial 12 months. Oncologists registered patients with nonquamous histology for EGFR mutation testing using a Web-based platform. Basic demographics were collected including age, histology, sex, smoking status, and ethnicity. The decision to prescribe gefitinib was subsequently registered on the system.Results:Between March and December 2010, 2104 requests were received for EGFR mutation testing. Demographic details are as follows: adenocarcinoma (91.6%); Asian ethnicity (13.9%); female (58%); light/never smoker (41.3%); stage IV disease (87.1%). The number of tests requested each month ranged from 200 to 250. Mutation testing was conducted in 1771 of 2104 requests (84%). The median turnaround time for EGFR testing was 18 days (standard deviation 9.7). Gefitinib was prescribed in 302 patients (17.1%). The number of test requests dropped to 50 to 100 per month at the end of the initial 12 months.Conclusion:There was rapid uptake of EGFR mutation testing into routine clinical practice in Canada. Uptake of EGFR mutation testing dropped substantially once funding from pharmaceutical industry was discontinued. There is a need for a national strategy to ensure resources are in place to implement molecular testing for new molecularly targeted agents
Hubble flow variance and the cosmic rest frame
We characterize the radial and angular variance of the Hubble flow in the
COMPOSITE sample of 4534 galaxies, on scales in which much of the flow is in
the nonlinear regime. With no cosmological assumptions other than the existence
of a suitably averaged linear Hubble law, we find with decisive Bayesian
evidence (ln B >> 5) that the Hubble constant averaged in independent spherical
radial shells is closer to its asymptotic value when referred to the rest frame
of the Local Group, rather than the standard rest frame of the Cosmic Microwave
Background. An exception occurs for radial shells in the range 40/h-60/h Mpc.
Angular averages reveal a dipole structure in the Hubble flow, whose amplitude
changes markedly over the range 32/h-62/h Mpc. Whereas the LG frame dipole is
initially constant and then decreases significantly, the CMB frame dipole
initially decreases but then increases. The map of angular Hubble flow
variation in the LG rest frame is found to coincide with that of the residual
CMB temperature dipole, with correlation coefficient -0.92. These results are
difficult to reconcile with the standard kinematic interpretation of the motion
of the Local Group in response to the clustering dipole, but are consistent
with a foreground non-kinematic anisotropy in the distance-redshift relation of
0.5% on scales up to 65/h Mpc. Effectively, the differential expansion of space
produced by nearby nonlinear structures of local voids and denser walls and
filaments cannot be reduced to a local boost. This hypothesis suggests a
reinterpretation of bulk flows, which may potentially impact on calibration of
supernovae distances, anomalies associated with large angles in the CMB
anisotropy spectrum, and the dark flow inferred from the kinematic
Sunyaev-Zel'dovich effect. It is consistent with recent studies that find
evidence for a non-kinematic dipole in the distribution of distant radio
sources.Comment: 37 pages, 9 tables, 13 figures; v2 adds extensive new analysis
(including additional subsections, tables, figures); v3 adds a Monte Carlo
analysis (with additional table, figure) which further tightens the
statistical robustness of the dipole results; v4 adds further clarifications,
small corrections, references and discussion of Planck satellite results; v5
typos fixed, matches published versio
A Method to Estimate the Boson Mass and to Optimise Sensitivity to Helicity Correlations of tau+tau- Final States
In proton-proton collisions at LHC energies, Z and low mass Higgs bosons
would be produced with high and predominantly longitudinal boost with respect
to the beam axis. This note describes a new analysis tool devised to handle
this situation in cases when such bosons decay to a pair of tau-leptons. The
tool reconstructs the rest frame of the tau+tau- pair by finding the boost that
minimises the acollinearity between the visible tau decay products. In most
cases this gives a reasonable approximation to the rest frame of the decaying
boson. It is shown how the reconstructed rest frame allows for a new method of
mass estimation. Also a considerable gain in sensitivity to helicity
correlations is obtained by analysing the tau-jets in the reconstructed frame
instead of using the laboratory momenta and energies, particularly when both
tau-leptons decay hadronically.Comment: 13 pages, method extended with 3D boost finde
The genome sequence and effector complement of the flax rust pathogen Melampsora lini
Rust fungi cause serious yield reductions on crops, including wheat, barley, soybean, coffee, and represent real threats to global food security. Of these fungi, the flax rust pathogen Melampsora lini has been developed most extensively over the past 80 years as a model to understand the molecular mechanisms that underpin pathogenesis. During infection, M. lini secretes virulence effectors to promote disease. The number of these effectors, their function and their degree of conservation across rust fungal species is unknown. To assess this, we sequenced and assembled de novo the genome of M. lini isolate CH5 into 21,130 scaffolds spanning 189 Mbp (scaffold N50 of 31 kbp). Global analysis of the DNA sequence revealed that repetitive elements, primarily retrotransposons, make up at least 45% of the genome. Using ab initio predictions, transcriptome data and homology searches, we identified 16,271 putative protein-coding genes. An analysis pipeline was then implemented to predict the effector complement of M. lini and compare it to that of the poplar rust, wheat stem rust and wheat stripe rust pathogens to identify conserved and species-specific effector candidates. Previous knowledge of four cloned M. lini avirulence effector proteins and two basidiomycete effectors was used to optimize parameters of the effector prediction pipeline. Markov clustering based on sequence similarity was performed to group effector candidates from all four rust pathogens. Clusters containing at least one member from M. lini were further analyzed and prioritized based on features including expression in isolated haustoria and infected leaf tissue and conservation across rust species. Herein, we describe 200 of 940 clusters that ranked highest on our priority list, representing 725 flax rust candidate effectors. Our findings on this important model rust species provide insight into how effectors of rust fungi are conserved across species and how they may act to promote infection on their hosts.This work
was funded by a grant from the CSIRO Transformational Biology
Capability Platform to Adnane Nemri. Claire Anderson was supported
by an ARC Discovery Grant (DP120104044) awarded to
David A. Jones and Peter N. Dodds
- …