159 research outputs found
Epidemiology and outcomes of Clostridium difficile infection in allogeneic hematopoietic cell and lung transplant recipients
BackgroundClostridium difficile infection (CDI) is a common complication of lung and allogeneic hematopoietic cell (HCT) transplant, but the epidemiology and outcomes of CDI after transplant are poorly described.MethodsWe performed a prospective, multicenter study of CDI within 365 days post‐allogeneic HCT or lung transplantation. Data were collected via patient interviews and medical chart review. Participants were followed weekly in the 12 weeks post‐transplant and while hospitalized and contacted monthly up to 18 months post‐transplantation.ResultsSix sites participated in the study with 614 total participants; 4 enrolled allogeneic HCT (385 participants) and 5 enrolled lung transplant recipients (229 participants). One hundred and fifty CDI cases occurred within 1 year of transplantation; the incidence among lung transplant recipients was 13.1% and among allogeneic HCTs was 31.2%. Median time to CDI was significantly shorter among allogeneic HCT than lung transplant recipients (27 days vs 90 days; P = .037). CDI was associated with significantly higher mortality from 31 to 180 days post‐index date among the allogeneic HCT recipients (Hazard ratio [HR] = 1.80; P = .007). There was a trend towards increased mortality among lung transplant recipients from 120 to 180 days post‐index date (HR = 4.7, P = .09).ConclusionsThe epidemiology and outcomes of CDI vary by transplant population; surveillance for CDI should continue beyond the immediate post‐transplant period.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143790/1/tid12855_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143790/2/tid12855.pd
Constraining Majorana neutrino electromagnetic properties from the LMA-MSW solution of the solar neutrino problem
In this paper we use solar neutrino data to derive stringent bounds on
Majorana neutrino transition moments (TMs). Should such be present, they would
contribute to the neutrino--electron scattering cross section and hence alter
the signal observed in Super-Kamiokande. Motivated by the growing robustness of
the LMA-MSW solution of the solar neutrino problem indicated by recent data,
and also by the prospects of its possible confirmation at KamLAND, we assume
the validity of this solution, and we constrain neutrino TMs by using the
latest global solar neutrino data. We find that all elements of the TM matrix
can be bounded at the same time. Furthermore, we show how reactor data play a
complementary role to the solar neutrino data, and use the combination of both
data sets to improve the current bounds. Performing a simultaneous fit of
LMA-MSW oscillation parameters and TMs we find that 6.3 times 10^{-10} mu_B and
2.0 times 10^{-10} mu_B are the 90% C.L. bounds from solar and combined solar +
reactor data, respectively. Finally, we perform a simulation of the upcoming
Borexino experiment and show that it will improve the bounds from today's data
by roughly one order of magnitude.Comment: Latex, 24 pages, 6 figures; misprints correcte
Lepton masses in a supersymmetric 3-3-1 model
We consider the mass generation for both charginos and neutralinos in a 3-3-1
supersymmetric model. We show that R-parity breaking interactions leave the
electron and one of the neutrinos massless at the tree level. However the same
interactions induce masses for these particles at the 1-loop level. Unlike the
similar situation in the MSSM the masses of the neutralinos are related to the
masses of the charginos.Comment: RevTex, 11 pages incluing 2 .eps figures. Extended published versio
Signal analysis and feature generation for pattern identification of partial discharges in high-voltage equipment
This paper proposes a method for the identification of different partial discharges (PDs) sources through the analysis of a collection of PD signals acquired with a PD measurement system. This method, robust and sensitive enough to cope with noisy data and external interferences, combines the characterization of each signal from the collection, with a clustering procedure, the CLARA algorithm.
Several features are proposed for the characterization of the signals, being the wavelet variances, the frequency estimated with the Prony method, and the energy, the most relevant for the performance of the clustering procedure.
The result of the unsupervised classification is a set of clusters each containing those signals which are more similar to each other than to those in other clusters. The analysis of the classification results permits both the identification of different PD sources and the discrimination between original PD signals, reflections, noise and external interferences.
The methods and graphical tools detailed in this paper have been coded and published as a contributed package of the R environment under a GNU/GPL license
Global analysis of neutrino oscillation data in four-neutrino schemes
We present an analysis of the global neutrino oscillation data in terms of four-neutrino mass schemes. We find that the strong preference of oscillations into active neutrinos implied by the latest solar as well as atmospheric neutrino data allows to rule out (2+2) mass schemes, whereas (3+1) schemes are strongly disfavoured by short-baseline experiments. Our analysis shows that four-neutrino oscillations do not provide a satisfactory description of the global neutrino oscillation data including the LSND result
Ruling out four-neutrino oscillation interpretations of the LSND anomaly?
Prompted by recent solar and atmospheric data, we re-analyze the
four-neutrino description of current global neutrino oscillation data,
including the LSND evidence for oscillations. The higher degree of rejection
for non-active solar and atmospheric oscillation solutions implied by the SNO
neutral current result as well as by the latest 1489-day Super-K atmospheric
neutrino data allows us to rule out (2+2) oscillation schemes proposed to
reconcile LSND with the rest of current neutrino oscillation data. Using an
improved goodness of fit (gof) method especially sensitive to the combination
of data sets we obtain a gof of only 1.6 times 10^{-6} for (2+2) schemes.
Further, we re-evaluate the status of (3+1) oscillations using two different
analyses of the LSND data sample. We find that also (3+1) schemes are strongly
disfavoured by the data. Depending on the LSND analysis we obtain a gof of 5.6
times 10^{-3} or 7.6 times 10^{-5}. This leads to the conclusion that all
four-neutrino descriptions of the LSND anomaly, both in (2+2) as well as (3+1)
realizations, are highly disfavoured. Our analysis brings the LSND hint to a
more puzzling status.Comment: 21 pages, 7 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
Damage evaluation during installation of geosynthetics used in asphalt pavements
Geosynthetics are commonly used as anti-reflective cracking systems in asphalt pavements. The rehabilitation design methods use the characteristics of as-received geosynthetics as inputs. However, these materials undergo physical damage during their installation due to mechanical and thermal loads which currently are not taken into account in the design processes. These loads can produce a reduction in geosynthetic strength and therefore, it is necessary to know the secant modulus after installation in order to improve the pavement design incorporating these materials. The secant modulus of a material indicates its initial stiffness. This paper describes an experimental study of damage due to installation of five different geosynthetics using three different procedures: (i) mechanical damage induced in the laboratory considering the action of aggregates, (ii) in situ mechanical and thermal damage due to actual installation in a test section, and (iii) a new mechanical and thermal damage experimental test developed with the aim of reproducing the real installation conditions. The main results of the study indicate that the obtained secant modulus of the tested geosynthetics reduced after applying the three damage procedures, and the loss of properties differed depending on the type and constitutive material and on the applied damage procedure.This investigation was supported by the research Project
‘Rehabilitation of roads and highways (REHABCAR)’
file number IPT-370000–2010–029, led by DRAGADOS
(ACS Group), in collaboration with GEOCISA and
ASFALTOS AUGUSTA among others. The project has
been funded by the Ministry of Economy and Competitiveness
(MINECO) within the National Plan for Scientific
Research, Development and Innovation 2008–2011
(INNPACTO 2010) and the European Union under
ERDF Funds (European Regional Development Fund)
Confusing non-standard neutrino interactions with oscillations at a neutrino factory
Most neutrino mass theories contain non-standard interactions (NSI) of
neutrinos which can be either non-universal (NU) or flavor-changing (FC). We
study the impact of such interactions on the determination of neutrino mixing
parameters at a neutrino factory using the so-called ``golden channels''
\pnu{e}\to\pnu{\mu} for the measurement of \theta_{13}. We show that a certain
combination of FC interactions in neutrino source and earth matter can give
exactly the same signal as oscillations arising due to \theta_{13}. This
implies that information about \theta_{13} can only be obtained if bounds on
NSI are available. Taking into account the existing bounds on FC interactions,
this leads to a drastic loss in sensitivity in \theta_{13}, at least two orders
of magnitude. A near detector at a neutrino factory offers the possibility to
obtain stringent bounds on some NSI parameters. Such near site detector
constitutes an essential ingredient of a neutrino factory and a necessary step
towards the determination of \theta_{13} and subsequent study of leptonic CP
violation.Comment: 23 pages, 5 figures, improved version, accepted for publication in
Phs. Rev. D, references adde
Leptogenesis and Neutrino Oscillations Within A Predictive G(224)/SO(10)-Framework
A framework based on an effective symmetry that is either G(224)= SU(2)_L x
SU(2)_R xSU(4)^c or SO(10) has been proposed (a few years ago) that
successfully describes the masses and mixings of all fermions including
neutrinos, with seven predictions, in good accord with the data. Baryogenesis
via leptogenesis is considered within this framework by allowing for natural
phases (~ 1/20-1/2) in the entries of the Dirac and Majorana mass-matrices. It
is shown that the framework leads quite naturally, for both thermal as well as
non-thermal leptogenesis, to the desired magnitude for the baryon asymmetry.
This result is obtained in full accord with the observed features of the
atmospheric and solar neutrino oscillations, as well as with those of the quark
and charged lepton masses and mixings, and the gravitino-constraint. Hereby one
obtains a unified description of fermion masses, neutrino oscillations and
baryogenesis (via leptogenesis) within a single predictive framework.Comment: Efficiency factor updated, some clarifications and new references
added. 19 page
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