493 research outputs found
Interplay between perturbative and non-perturbative effects in the stealthy Higgs model
We study corrections to electroweak precision variables in a model with
strongly interacting singlet Higgs particles.Comment: 31 pages, Latex, 11 figure
Resonance in Strong WW Rescattering in Massive SU(2) Gauge Theory
We investigate the effects of WW rescattering through strong anomalous
four-vector boson couplings. In the I=1, J=1 channel, we find a resonance with
a mass of approximately 200 GeV and a width of less than 12 GeV. In an
application to pion physics we find a small correction to the KSRF relation.Comment: 21 pages, extended discussion, some minor change
Density-metric unimodular gravity:vacuum spherical symmetry
We analyze an alternative theory of gravity characterized by metrics that are
tensor density of rank(0,2)and weight-1/2.The metric compatibility condition is
supposed to hold. The simplest expression for the action of gravitational field
is used.Taking the metric and trace of connections as dynamical variables,the
field equations in the absence of matter and other kinds of sources are
derived.The solutions of these equations are obtained for the case of vacuum
static spherical symmetric spacetime.The null geodesics and advance of
perihelion of ellipes are discussed.We confirm a subclass of solutions is
regular for r>0 and there is no event horizon while it is singular at r=0.Comment: 15 pages,no,figures,typos corrected,new section added,published
versio
Gravitational anomaly and fundamental forces
I present an argument, based on the topology of the universe, why there are
three generations of fermions. The argument implies a preferred gauge group of
SU(5), but with SO(10) representations of the fermions. The breaking pattern
SU(5) to SU(3)xSU(2)xU(1) is preferred over the pattern SU(5) to SU(4)xU(1). On
the basis of the argument one expects an asymmetry in the early universe
microwave data, which might have been detected already.Comment: Contribution to the 2nd School and Workshop on Quantum Gravity and
Quantum Geometry. Corfu, september 13-20 2009. 10 page
Heavy Fermion Screening Effects and Gauge Invariance
We show that the naively expected large virtual heavy fermion effects in low
energy processes may be screened if the process under consideration contains
external gauge bosons constrained by gauge invariance. We illustrate this by a
typical example of the process . Phenomenological
implications are also briefly indicated.Comment: a miss-print fixed, 7 pages, LaTex, no figure
Prognosis and prognostic factors of patients with mesothelioma:A population-based study
BACKGROUND: It is important to regularly update survival estimates of patients with malignant mesothelioma as prognosis may vary according to epidemiologic factors and diagnostic and therapeutic management. METHODS: We assessed overall (baseline) survival as well as related prognostic variables in a large cohort of 1353 patients with a confirmed diagnosis of malignant mesothelioma between 2005 and 2008. RESULTS: About 50% of the patients were 70 years or older at diagnosis and the median latency time since start of asbestos exposure was 49 years. One year after diagnosis, 47% of the patients were alive, 20% after 2 years and 15% after 3 years. Prognostic variables independently associated with worse survival were: older age (HR=1.04 per year 95% CI (1.03–1.06)), sarcomatoid subtype (HR=2.45 95% CI (2.06–2.90)) and non-pleural localisation (HR=1.67 95% CI (1.26–2.22)). CONCLUSION: Survival of patients with malignant mesothelioma is still limited and depends highly on patient age, mesothelioma subtype and localisation. In addition, a substantial part of the patients had a long latency time between asbestos exposure and diagnosis
Mini-Proceedings of the 15th meeting of the Working Group on Rad. Corrections and MC Generators for Low Energies
The mini-proceedings of the 15th Meeting of the "Working Group on Rad.
Corrections and MC Generators for Low Energies" held in Mainz on April 11,
2014, are presented. These meetings, started in 2006, have as aim to bring
together experimentalists and theorists working in the fields of meson
transition form factors, hadronic contributions to and the
effective fine structure constant, and development of Monte Carlo generators
and Radiative Corrections for precision e+e- and tau physics.Comment: 21 pages, 7 contributions. Editors: S. E. Mueller and G. Venanzon
Incomplete quality of life data in lung transplant research: comparing cross sectional, repeated measures ANOVA, and multi-level analysis
BACKGROUND: In longitudinal studies on Health Related Quality of Life (HRQL) it frequently occurs that patients have one or more missing forms, which may cause bias, and reduce the sample size. Aims of the present study were to address the problem of missing data in the field of lung transplantation (LgTX) and HRQL, to compare results obtained with different methods of analysis, and to show the value of each type of statistical method used to summarize data. METHODS: Results from cross-sectional analysis, repeated measures on complete cases (ANOVA), and a multi-level analysis were compared. The scores on the dimension 'energy' of the Nottingham Health Profile (NHP) after transplantation were used to illustrate the differences between methods. RESULTS: Compared to repeated measures ANOVA, the cross-sectional and multi-level analysis included more patients, and allowed for a longer period of follow-up. In contrast to the cross sectional analyses, in the complete case analysis, and the multi-level analysis, the correlation between different time points was taken into account. Patterns over time of the three methods were comparable. In general, results from repeated measures ANOVA showed the most favorable energy scores, and results from the multi-level analysis the least favorable. Due to the separate subgroups per time point in the cross-sectional analysis, and the relatively small number of patients in the repeated measures ANOVA, inclusion of predictors was only possible in the multi-level analysis. CONCLUSION: Results obtained with the various methods of analysis differed, indicating some reduction of bias took place. Multi-level analysis is a useful approach to study changes over time in a data set where missing data, to reduce bias, make efficient use of available data, and to include predictors, in studies concerning the effects of LgTX on HRQL
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