170 research outputs found
Muon-anti-neutrino <---> electron-anti-neutrino mixing: analysis of recent indications and implications for neutrino oscillation phenomenology
We reanalyze the recent data from the Liquid Scintillator Neutrino Detector
(LSND) experiment, that might indicate anti-nu_muanti-nu_e mixing. This
indication is not completely excluded by the negative results of established
accelerator and reactor neutrino oscillation searches. We quantify the region
of compatibility by means of a thorough statistical analysis of all the
available data, assuming both two-flavor and three-flavor neutrino
oscillations. The implications for various theoretical scenarios and for future
oscillation searches are studied. The relaxation of the LSND constraints under
different assumptions in the statistical analysis is also investigated.Comment: 17 pages (RevTeX) + 9 figures (Postscript) included with epsfig.st
Super-Kamiokande atmospheric neutrino data, zenith distributions, and three-flavor oscillations
We present a detailed analysis of the zenith angle distributions of
atmospheric neutrino events observed in the Super-Kamiokande (SK) underground
experiment, assuming two-flavor and three-flavor oscillations (with one
dominant mass scale) among active neutrinos. In particular, we calculate the
five angular distributions associated to sub-GeV and multi-GeV \mu-like and
e-like events and to upward through-going muons, for a total of 30 accurately
computed observables (zenith bins). First we study how such observables vary
with the oscillation parameters, and then we perform a fit to the experimental
data as measured in SK for an exposure of 33 kTy (535 days). In the two-flavor
mixing case, we confirm the results of the SK Collaboration analysis, namely,
that \nu_\mu\nu_\tau oscillations are preferred over \nu_\mu\nu_e,
and that the no oscillation case is excluded with high confidence. In the
three-flavor mixing case, we perform our analysis with and without the
additional constraints imposed by the CHOOZ reactor experiment. In both cases,
the analysis favors a dominance of the \nu_\mu\nu_\tau channel. Without
the CHOOZ constraints, the amplitudes of the subdominant \nu_\munu_e and
\nu_e\nu_\tau transitions can also be relatively large, indicating that,
at present, current SK data do not exclude sizable \nu_e mixing by themselves.
After combining the CHOOZ and SK data, the amplitudes of the subdominant
transitions are constrained to be smaller, but they can still play a
nonnegligible role both in atmospheric and other neutrino oscillation searches.
In particular, we find that the \nu_e appearance probability expected in long
baseline experiments can reach the testable level of ~15%.Comment: 35 pages (RevTeX), including 20 ps figures (with epsfig.sty
Accelerator and Reactor Neutrino Oscillation Experiments in a Simple Three-Generation Framework
We present a new approach to the analysis of neutrino oscillation
experiments, in the one mass-scale limit of the three-generation scheme. In
this framework we reanalyze and recombine the most constraining accelerator and
reactor data, in order to draw precise bounds in the new parameter space. We
consider our graphical representations as particularly suited to show the
interplay among the different oscillation channels. Within the same framework,
the discovery potential of future short and long baseline experiments is also
investigated, in the light of both the recent signal from the LSND experiment
and the atmospheric neutrino anomaly.Comment: uuencoded compressed tar file. Figures (13) available by ftp to
ftp://eku.sns.ias.edu/pub/lisi/ (192.16.204.30). Submitted to Physical Review
Three-flavor atmospheric neutrino anomaly
We investigate the indications of flavor oscillations that come from the
anomalous flavor composition of the atmospheric neutrino flux observed in some
underground experiments. We study the information coming from the
neutrino-induced -like and -like events both in the sub-GeV energy
range (Kamiokande, IMB, Fr{\'e}jus, and NUSEX experiments) and in the multi-GeV
energy range (Kamiokande experiment). First we analyze all the data in the
limits of pure and
oscillations. We obtain that
oscillations provide a better fit, in particular
to the multi-GeV data. Then we perform a three-flavor analysis in the
hypothesis of dominance of one neutrino square mass difference, , implying
that the neutrino mixing is parametrized by two angles,
. We explore the space
exhaustively, and find the regions favored by the oscillation hypothesis. The
results are displayed in a form suited to the comparison with other flavor
oscillation searches at accelerator, reactor, and solar experiments. In
the analysis, we pay particular attention to the earth matter effects, to the
correlation of the uncertainties, and to the symmetry properties of the
oscillation probability.Comment: 25 pages (RevTeX) + 12 figures, requires epsfig.sty. All the figures
are bitmapped. Postscript figures with full resolution are available at
ftp://ftp.sns.ias.edu/pub/lisi/atmpaper
Effectiveness of benralizumab in severe eosinophilic asthma: Distinct sub-phenotypes of response identified by cluster analysis.
Background: Benralizumab is effective in severe eosinophilic asthma (SEA), but suboptimal responses are observed in some patients. Although several factors have been associated with benralizumab response, no cluster analysis has yet been undertaken to identify different responsiveness sub-phenotypes. Objective: To identify SEA sub-phenotypes with differential responsiveness to benralizumab. Methods: One hundred and five patients diagnosed with SEA who had completed 6 months of benralizumab treatment were included in a hierarchical cluster analysis based on a set of clinical variables that can be easily collected in routine practice (age, age at disease onset, disease length, allergen sensitization status, blood eosinophil count, IgE levels, FEV1% predicted, nasal polyposis, bronchiectasis). Results: Four clusters were identified: Clusters 2 and 3 included patients with high levels of both IgE and eosinophils (type-2 biomarkers high), whereas Clusters 1 and 4 included patients with only one type-2 biomarker at a high level: IgE in Cluster 1 and eosinophils in Cluster 4. Clusters 2 and 3 (both type-2 biomarkers high) showed the highest response rate to benralizumab in terms of elimination of exacerbations (79% and 80% respectively) compared to Clusters 1 and 4 (52% and 60% respectively). When super-response (the absence of exacerbation without oral corticosteroid use) was assessed, Cluster 2, including patients with more preserved lung function than the other clusters, but comparable exacerbation rate, oral corticosteroid use and symptom severity, was the most responsive cluster (87.5% of patients). Conclusions: Our cluster analysis identified benralizumab differential response sub-phenotypes in SEA, with the potential of improving disease treatment and precision management
Fixation of osteochondral fragments in the human knee using Meniscus Arrows®
The aim of this study is to compare the hold in bone of Meniscus Arrows® and Smart Nails®, followed by the report of the results of the clinical application of Meniscus Arrows® as fixation devices. First, pull-out tests were performed to analyse the holdfast of both nails in bone. Statistical analysis showed no significant difference; therefore, the thinner Meniscus Arrow® was chosen as fixation device in the patient series of two patients with a symptomatic Osteochondritis dissecans fragment and three patients with an osteochondral fracture of a femur condyle. The cartilage margins were glued with Tissuecoll®. All fragments consolidated. Second look arthroscopy in three patients showed fixed fragments with stable, congruent cartilage edges. At an average follow-up period of 5 years no pain, effusion, locking, restricted range of motion or signs of osteoarthritis were reported. Based on the results of the pull-out tests and available clinical studies, Meniscus Arrows® and Smart Nails® are both likely to perform adequately as fixation devices in the treatment of Osteochondritis dissecans and osteochondral fractures in the knee. They both provide the advantage of one stage surgery. However, based on their smaller diameter, the Meniscus Arrows® should be preferred for this indication
Women Born Preterm or with Inappropriate Weight for Gestational Age Are at Risk of Subsequent Gestational Diabetes and Pre-Eclampsia
Introduction: Low birthweight, which can be caused by inappropriate intrauterine growth or prematurity, is associated with development of gestational diabetes mellitus (GDM) as well as pre-eclampsia later in life, but the relative effects of prematurity and inappropriate intrauterine growth remain uncertain. Methods: Through nation-wide registries we identified all Danish mothers in the years 1989–2007. Two separate cohorts consisting mothers born 1974–1977 (n = 84219) and 1978–1981 (n = 32376) were studied, due to different methods o
Testing violations of special and general relativity through the energy dependence of nu_mu<--->nu_tau oscillations in the Super-Kamiokande atmospheric neutrino experiment
The atmospheric neutrino data collected by the Super-Kamiokande experiment
span about four decades in neutrino energy E, and are thus appropriate to probe
the energy dependence of the oscillation wavelength \lambda associated to
nu_munu_tau flavor transitions, when these are assumed to explain the
data. Such dependence takes the form \lambda^{-1}\propto E^n in a wide class of
theoretical models, including ``standard'' oscillations due to neutrino mass
and mixing (n=-1), energy-independent oscillations (n=0), and violations of the
equivalence principle or of Lorentz invariance (n=1). We study first how the
theoretical zenith distributions of sub-GeV, multi-GeV, and upward-going muon
events change for different integer values of n. Then we perform a detailed
analysis of the Super-Kamiokande data by treating the energy exponent n as a
free parameter, with unconstrained scale factors for both the amplitude and the
phase of nu_munu_tau oscillations. We find a best-fit range n=-0.9 \pm 0.4
at 90% C.L., which confirms the standard scenario (n=-1) as the dominant
oscillation mechanism, and strongly constrains possible concurrent exotic
processes (n \neq -1). In particular, we work out the interesting case of
leading standard oscillations plus subleading terms induced by violations of
special or general relativity principles, and obtain extremely stringent upper
bounds on the amplitude of such violations in the (nu_mu,nu_tau) sector.Comment: 13 pages (RevTeX) + 6 figures (PostScript, color). Requires
epsfig.st
Reconciling solar and terrestrial neutrino oscillation evidences with minimum sacrifice
The present possible evidences in favor of neutrino masses and mixings from
solar, atmospheric, and accelerator experiments cannot be all reconciled in a
three-family framework, unless some data are excluded. We grade all possible
three-family scenarios according to their compatibility with the available
data. A recently proposed scenario appears to emerge naturally as the most
likely solution to all oscillation evidences, with the only exception of the
angular dependence of multi-GeV atmospheric data in the Kamiokande experiment.
We describe in detail the status and the phenomenological implications of this
``minimum sacrifice'' solution.Comment: 16 pages (RevTeX) + 3 figures (postscript); requires epsfig.st
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