2,795 research outputs found
Long-term follow-up of asymptomatic or mildly symptomatic patients with severe degenerative mitral regurgitation and preserved left ventricular function
OBJECTIVES:
The timing for mitral valve surgery in asymptomatic patients with severe mitral regurgitation and preserved left ventricular function remains controversial. We analyzed the immediate and long-term outcomes of these patients after surgery.
METHODS:
From January 1992 to December 2012, 382 consecutive patients with severe chronic degenerative mitral regurgitation, with no or mild symptoms, and preserved left ventricular function (ejection fraction ≥ 60%) were submitted to surgery and followed for up to 22 years (3209 patient-years). Patients with associated surgeries, other than tricuspid valve repair, were excluded. Cox proportional-hazard survival analysis was performed to determine predictors of late mortality and mitral reoperation. Subgroup analysis involved patients with atrial fibrillation or pulmonary hypertension.
RESULTS:
Mitral valvuloplasty was performed in 98.2% of cases. Thirty-day mortality was 0.8%. Overall survival at 5, 10, and 20 years was 96.3% ± 1.0%, 89.7% ± 2.0%, and 72.4% ± 5.8%, respectively, and similar to the expected age- and gender-adjusted general population. Patients with atrial fibrillation/pulmonary hypertension had a 2-fold risk of late mortality compared with the remaining patients (hazard ratio, 2.54; 95% confidence interval, 1.17-4.80; P = .018). Benefit was age-dependent only in younger patients (<65 years; P = .016). Patients with atrial fibrillation/pulmonary hypertension (hazard ratio, 4.20, confidence interval, 1.10-11.20; P = .037) and patients with chordal shortening were at increased risk for reoperation, whereas patients with P2 prolapse (hazard ratio, 0.06; confidence interval, 0.008-0.51; P = .037) and patients with myxomatous valves (hazard ratio, 0.072; confidence interval, 0.008-0.624; P = .017) were at decreased risk.
CONCLUSIONS:
Mitral valve repair can be achieved in the majority of patients with low mortality (<1%) and excellent long-term survival. Patients with atrial fibrillation/pulmonary hypertension had compromised long-term survival, particularly younger patients (aged <65 years), and are at increased risk of mitral reoperation.info:eu-repo/semantics/publishedVersio
Refining the scalar and tensor contributions in decays
In this article we analyze the contribution from intermediate spin-0 and
spin-2 resonances to the decay by means of a chiral
invariant Lagrangian incorporating these mesons. In particular, we study the
corresponding axial-vector form-factors. The advantage of this procedure with
respect to previous analyses is that it incorporates chiral (and isospin)
invariance and, hence, the partial conservation of the axial-vector current.
This ensures the recovery of the right low-energy limit, described by chiral
perturbation theory, and the transversality of the current in the chiral limit
at all energies. Furthermore, the meson form-factors are further improved by
requiring appropriate QCD high-energy conditions. We end up with a brief
discussion on its implementation in the Tauola Monte Carlo and the prospects
for future analyses of Belle's data.Comment: 32 pages, 13 figures. Extended discussion on the numerical importance
of the tensor and scalar resonances and the parametrization of the scalar
propagator. Version published in JHE
Non-resonant leptogenesis in seesaw models with an almost conserved B-L
We review the motivations and some results on leptogenesis in seesaw models
with an almost conserved lepton number. The paper is based on a talk given at
the 5th International Symposium on Symmetries in Subatomic Physics, SSP2012.Comment: 8 pages, 1 figure. Published in the proceedings of the 5th
International Symposium on Symmetries in Subatomic Physics, SSP201
Ecology: a prerequisite for malaria elimination and eradication
* Existing front-line vector control measures, such as insecticide-treated nets and residual sprays, cannot break the transmission cycle of Plasmodium falciparum in the most intensely endemic parts of Africa and the Pacific
* The goal of malaria eradication will require urgent strategic investment into understanding the ecology and evolution of the mosquito vectors that transmit malaria
* Priority areas will include understanding aspects of the mosquito life cycle beyond the blood feeding processes which directly mediate malaria transmission
* Global commitment to malaria eradication necessitates a corresponding long-term commitment to vector ecolog
Non-standard interactions versus non-unitary lepton flavor mixing at a neutrino factory
The impact of heavy mediators on neutrino oscillations is typically described
by non-standard four-fermion interactions (NSIs) or non-unitarity (NU). We
focus on leptonic dimension-six effective operators which do not produce
charged lepton flavor violation. These operators lead to particular
correlations among neutrino production, propagation, and detection non-standard
effects. We point out that these NSIs and NU phenomenologically lead, in fact,
to very similar effects for a neutrino factory, for completely different
fundamental reasons. We discuss how the parameters and probabilities are
related in this case, and compare the sensitivities. We demonstrate that the
NSIs and NU can, in principle, be distinguished for large enough effects at the
example of non-standard effects in the --sector, which basically
corresponds to differentiating between scalars and fermions as heavy mediators
as leading order effect. However, we find that a near detector at superbeams
could provide very synergistic information, since the correlation between
source and matter NSIs is broken for hadronic neutrino production, while NU is
a fundamental effect present at any experiment.Comment: 32 pages, 5 figures. Final version published in JHEP. v3: Typo in Eq.
(27) correcte
Pseudomoduli Dark Matter and Quiver Gauge Theories
We investigate supersymmetric models for dark matter which is represented by
pseudomoduli in weakly coupled hidden sectors. We propose a scheme to add a
dark matter sector to quiver gauge theories with metastable supersymmetry
breaking. We discuss the embedding of such scheme in string theory and we
describe the dark matter sector in terms of D7 flavour branes. We explore the
phenomenology in various regions of the parameters.Comment: 24 pages, 12 figures, JHEP3.cl
Non-unitary Leptonic Mixing and Leptogenesis
We investigate the relation between non-unitarity of the leptonic mixing
matrix and leptogenesis. We discuss how all parameters of the canonical type-I
seesaw mechanism can, in principle, be reconstructed from the neutrino mass
matrix and the deviation of the effective low-energy leptonic mixing matrix
from unitary. When the mass M' of the lightest right-handed neutrino is much
lighter than the masses of the others, we show that its decay asymmetries
within flavour-dependent leptogenesis can be expressed in terms of two
contributions, one depending on the unique dimension five (d=5) operator
generating neutrino masses and one depending on the dimension six (d=6)
operator associated with non-unitarity. In low-energy seesaw scenarios where
small lepton number violation explains the smallness of neutrino masses, the
lepton number conserving d=6 operator contribution generically dominates over
the d=5 operator contribution which results in a strong enhancement of the
flavour-dependent decay asymmetries without any resonance effects. To calculate
the produced final baryon asymmetry, the flavour equilibration effects directly
related to non-unitarity have to be taken into account. In a simple realization
of this non-unitarity driven leptogenesis, the lower bound on M' is found to be
about 10^8 GeV at the onset of the strong washout regime, more than one order
of magnitude below the bound in "standard" thermal leptogenesis.Comment: 19 pages, REVTeX4, 2 eps and 2 axodraw figure
Mixed Mediation of Supersymmetry Breaking with Anomalous U(1) Gauge Symmetry
Models with anomalous U(1) gauge symmetry contain various superfields which
can have nonzero supersymmetry breaking auxiliary components providing the
origin of soft terms in the visible sector, e.g. the U(1) vector superfield,
the modulus or dilaton superfield implementing the Green-Schwarz anomaly
cancellation mechanism, U(1)-charged but standard model singlet matter
superfield required to cancel the Fayet-Iliopoulos term, and finally the
supergravity multiplet. We examine the relative strength between these
supersymmetry breaking components in a simple class of models, and find that
various different mixed mediations of supersymmetry breaking, involving the
modulus, gauge, anomaly and D-term mediations, can be realized depending upon
the characteristics of D-flat directions and how those D-flat directions are
stabilized with a vanishing cosmological constant. We identify two parameters
which represent such properties and thus characterize how the various
mediations are mixed. We also discuss the moduli stabilization and soft terms
in a variant of KKLT scenario, in which the visible sector K\"ahler modulus is
stabilized by the D-term potential of anomalous U(1) gauge symmetry.Comment: 30 pages, 5 figure
Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers
This work was supported by the Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), grants E-26/202.974/2015 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants 229755/2013-5, Brazil. LMLB is a senior research fellow of CNPq and Faperj. NG acknowledged support from the Wellcome Trust (Trust (097377, 101873, 200208) and MRC Centre for Medical Mycology (MR/N006364/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
Flavoured soft leptogenesis and natural values of the B term
We revisit flavour effects in soft leptogenesis relaxing the assumption of
universality for the soft supersymmetry breaking terms. We find that with
respect to the case in which the heavy sneutrinos decay with equal rates and
equal CP asymmetries for all lepton flavours, hierarchical flavour
configurations can enhance the efficiency by more than two orders of magnitude.
This translates in more than three order of magnitude with respect to the
one-flavour approximation. We verify that lepton flavour equilibration effects
related to off-diagonal soft slepton masses are ineffective for damping these
large enhancements. We show that soft leptogenesis can be successful for
unusual values of the relevant parameters, allowing for and for values of the washout parameter up to .Comment: 23 pages, 5 figures postscript, Minor changes to match the published
version in JHE
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