1,754 research outputs found
6Li direct breakup lifetimes
alpha-d coincidence data were studied for the 6Li + 59Co reaction at E(lab) =
29.6 MeV. By using a kinematic analysis, it was possible to identify which
process, leading to the same final state, has the major contribution for each
of the selected angular regions. Contributions of the 6Li sequential and direct
breakup to the incomplete fusion/transfer process were discussed by considering
the lifetimes obtained by using a semiclassical approach, for both breakup
components.Comment: 5 pages, 4 figures, Invited Talk (Parrallel Sessions) of A. Szanto de
Toledo, prepared for the Proccedings of the 10th International Conference on
Nucleus-Nucleus Collisions, August 16-21, 2009, Beijing, China; submitted to
Nucl. Phys. A (Proceedings of NN2009
Reaction mechanisms for weakly-bound, stable nuclei and unstable, halo nuclei on medium-mass targets
An experimental overview of reactions induced by the stable, but weakly-bound
nuclei 6Li, 7Li and 9Be, and by the exotic, halo nuclei 6He, 8B, 11Be and 17F
on medium-mass targets, such as 58Ni, 59Co or 64Zn, is presented. Existing data
on elastic scattering, total reaction cross sections, fusion processes, breakup
and transfer channels are discussed in the framework of a CDCC approach taking
into account the breakup degree of freedom.Comment: 7 pages, 6 figures, Invited Talk given by C. Beck to the 10th
International Conference on Nucleus-Nucleus Collisions, August 16-21, 2009
Beijing, China; Paper submitted to the NN2009 Proceedings, Nuclear Physics A
(to be published
Propagators and WKB-exactness in the plane wave limit of AdSxS
Green functions for the scalar, spinor and vector fields in a plane wave
geometry arising as a Penrose limit of are obtained. The
Schwinger-DeWitt technique directly gives the results in the plane wave
background, which turns out to be WKB-exact. Therefore the structural
similarity with flat space results is unveiled. In addition, based on the local
character of the Penrose limit, it is claimed that for getting the correct
propagators in the limit one can rely on the first terms of the direct geodesic
contribution in the Schwinger-DeWitt expansion of the original propagators .
This is explicitly shown for the Einstein Static Universe, which has the same
Penrose limit as with equal radii, and for a number of other
illustrative cases.Comment: 18 pages, late
Can slow roll inflation induce relevant helical magnetic fields?
We study the generation of helical magnetic fields during single field
inflation induced by an axial coupling of the electromagnetic field to the
inflaton. During slow roll inflation, we find that such a coupling always leads
to a blue spectrum with , as long as the theory is treated
perturbatively. The magnetic energy density at the end of inflation is found to
be typically too small to backreact on the background dynamics of the inflaton.
We also show that a short deviation from slow roll does not result in strong
modifications to the shape of the spectrum. We calculate the evolution of the
correlation length and the field amplitude during the inverse cascade and
viscous damping of the helical magnetic field in the radiation era after
inflation. We conclude that except for low scale inflation with very strong
coupling, the magnetic fields generated by such an axial coupling in single
field slow roll inflation with perturbative coupling to the inflaton are too
weak to provide the seeds for the observed fields in galaxies and clusters.Comment: 33 pages 6 figures; v4 to match the accepted version to appear in
JCA
Sex differences in mortality in patients with COPD
Little is known about survival and clinical prognostic factors in females with chronic
obstructive pulmonary disease (COPD). The aim of the present study was to determine the
survival difference between males and females with COPD and to compare the value of the
different prognostic factors for the disease.
In total, 265 females and 272 males with COPD matched at baseline by BODE (body mass index,
airflow obstruction, dyspnoea, exercise capacity) and American Thoracic Society/European
Respiratory Society/Global Initiative of Chronic Obstructive Lung Disease criteria were
prospectively followed. Demographics, lung function, St George’s Respiratory Questionnaire,
BODE index, the components of the BODE index and comorbidity were determined. Survival was
documented and sex differences were determined using Kaplan–Meier analysis. The strength of
the association of the studied variables with mortality was determined using multivariate and
receiver operating curves analysis.
All-cause (40 versus 18%) and respiratory mortality (24 versus 10%) were higher in males than
females. Multivariate analysis identified the BODE index in females and the BODE index and
Charlson comorbidity score in males as the best predictors of mortality. The area under the curve
of the BODE index was a better predictor of mortality than the forced expiratory volume in one
second for both sexes.
At similar chronic obstructive pulmonary disease severity by BODE index and forced expiratory
volume in one second, females have significantly better survival than males. For both sexes the
BODE index is a better predictor of survival than the forced expiratory volume in one second
Reaction mechanisms in the 6Li+59Co system
The reactions induced by the weakly bound 6Li projectile interacting with the
intermediate mass target 59Co were investigated. Light charged particles
singles and - coincidence measurements were performed at the near
barrier energies E_lab = 17.4, 21.5, 25.5 and 29.6 MeV. The main contributions
of the different competing mechanisms are discussed. A statistical model
analysis, Continuum-Discretized Coupled-Channels calculations and two-body
kinematics were used as tools to provide information to disentangle the main
components of these mechanisms. A significant contribution of the direct
breakup was observed through the difference between the experimental sequential
breakup cross section and the CDCC prediction for the non-capture breakup cross
section.Comment: 30 pages, 8 figure
Status of a hybrid three-neutrino interpretation of neutrino data
We reanalyze the non-standard interaction (NSI) solutions to the solar
neutrino problem in the light of the latest solar, atmospheric and reactor
neutrino data. We show that such solutions, although preferred by the solar
data and consistent with the oscillation description of the atmospheric
neutrino data, are ruled out by the first results of the KamLAND reactor
experiment, at more than 3_sigma.Comment: 19 pages, LaTeX file using Elsart, 2 tables and 4 figures included.
This version updates the one published in Nucl.Phys.B629:479-490,2002 by
including the new KamLAND dat
CP Phases in Correlated Production and Decay of Neutralinos in the Minimal Supersymmetric Standard Model
We investigate the associated production of neutralinos
accompanied by the neutralino
leptonic decay , taking into
account initial beam polarization and production-decay spin correlations in the
minimal supersymmetric standard model with general CP phases but without
generational mixing in the slepton sector. The stringent constraints from the
electron EDM on the CP phases are also included in the discussion. Initial beam
polarizations lead to three CP--even distributions and one CP--odd
distribution, which can be studied independently of the details of the
neutralino decays. We find that the production cross section and the branching
fractions of the leptonic neutralino decays are very sensitive to the CP
phases. In addition, the production--decay spin correlations lead to several
CP--even observables such as lepton invariant mass distribution, and lepton
angular distribution, and one interesting T--odd (CP--odd) triple product of
the initial electron momentum and two final lepton momenta, the size of which
might be large enough to be measured at the high--luminosity future
electron--positron collider or can play a complementary role in constraining
the CP phases with the EDM constraints.Comment: Revtex, 37 pages, 12 eps figure
in NonCommutative Standard Model
We study the top quark decay to b quark and W boson in the NonCommutative
Standard Model (NCSM). The lowest contribution to the decay comes from the
terms quadratic in the matrix describing the noncommutative (NC) effects while
the linear term is seen to identically vanish because of symmetry. The NC
effects are found to be significant only for low values of the NC
characteristic scale.Comment: 11 page Latex file containing 2 eps figures (redrawn). More
discussion included. To appear in PR
Morphological evolution and classification of the red algal order Ceramiales inferred using plastid phylogenomics.
The order Ceramiales contains about one third of red algal diversity and it was classically classified into four families according to morphology. The first phylogenies based on one or two molecular markers were poorly supported and failed to resolve these families as monophyletic. Nine families are currently recognized, but relationships within and among them are poorly understood. We produced a well-resolved phylogeny for the Ceramiales using plastid genomes for 80 (28 newly sequenced) representative species of the major lineages. Three of the previously recognized families were resolved as independent monophyletic lineages: Ceramiaceae, Wrangeliaceae and Rhodomelaceae. By contrast, our results indicated that the other six families require reclassification. We propose the new order Inkyuleeales, a new circumscription of the Callithamniaceae to include the Spyridiaceae, and a new concept of the Delesseriaceae that includes the Sarcomeniaceae and the Dasyaceae. We also investigated the evolution of the thallus structure, which has been important in the classical delineation of families. The ancestor of the Ceramiales was a monosiphonous filament that evolved into more complex morphologies several times independently during the evolutionary history of this hyperdiverse lineage
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