211,195 research outputs found
Updated Global 3+1 Analysis of Short-BaseLine Neutrino Oscillations
We present the results of an updated fit of short-baseline neutrino
oscillation data in the framework of 3+1 active-sterile neutrino mixing. We
first consider and disappearance in the light of the
Gallium and reactor anomalies. We discuss the implications of the recent
measurement of the reactor spectrum in the NEOS experiment, which
shifts the allowed regions of the parameter space towards smaller values of
. The beta-decay constraints allow us to limit the oscillation
length between about 2 cm and 7 m at for neutrinos with an energy of
1 MeV. We then consider the global fit of the data in the light of the LSND
anomaly, taking into account the constraints from and
disappearance experiments, including the recent data of the MINOS and IceCube
experiments. The combination of the NEOS constraints on and the
MINOS and IceCube constraints on lead to an unacceptable
appearance-disappearance tension which becomes tolerable only in a pragmatic
fit which neglects the MiniBooNE low-energy anomaly. The minimization of the
global in the space of the four mixing parameters ,
, , and leads to three allowed
regions with narrow widths at (best-fit), 1.3 (at ), 2.4 (at ) eV. The
restrictions of the allowed regions of the mixing parameters with respect to
our previous global fits are mainly due to the NEOS constraints. We present a
comparison of the allowed regions of the mixing parameters with the
sensitivities of ongoing experiments, which show that it is likely that these
experiments will determine in a definitive way if the reactor, Gallium and LSND
anomalies are due to active-sterile neutrino oscillations or not.Comment: 39 pages; improved treatment of the reactor flux uncertainties and
other minor correction
Pitfalls in the analysis of low-temperature thermal conductivity of high-Tc cuprates
Recently, it was proposed that phonons are specularly reflected below about
0.5 K in ordinary single-crystal samples of high-T_c cuprates, and that the
low-temperature thermal conductivity should be analyzed by fitting the data up
to 0.5 K using an arbitrary power law. Such an analysis yields a result
different from that obtained from the conventional analysis, in which the
fitting is usually restricted to a region below 0.15 K. Here we show that the
proposed new analysis is most likely flawed, because the specular phonon
reflection means that the phonon mean free path \ell gets LONGER than the mean
sample width, while the estimated \ell is actually much SHORTER than the mean
sample width above 0.15 K.Comment: 4 pages, 1 figure; manuscript for the Proceedings of LEHTSC2007 to be
published in Journal of Physics: Conference Serie
Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2
The in-plane resistivity and thermal conductivity of
FeAs-based superconductor KFeAs single crystal were measured down to 50
mK. We observe non-Fermi-liquid behavior at =
5 T, and the development of a Fermi liquid state with when
further increasing field. This suggests a field-induced quantum critical point,
occurring at the superconducting upper critical field . In zero field
there is a large residual linear term , and the field dependence of
mimics that in d-wave cuprate superconductors. This indicates that
the superconducting gaps in KFeAs have nodes, likely d-wave symmetry.
Such a nodal superconductivity is attributed to the antiferromagnetic spin
fluctuations near the quantum critical point.Comment: 4 pages, 4 figures - replaces arXiv:0909.485
Crop classification using airborne radar and LANDSAT data
Airborne radar data acquired with a 13.3 GHz scatterometer over a test-site near Colby, Kansas were used to investigate the statistical properties of the scattering coefficient of three types of vegetation cover and of bare soil. A statistical model for radar data was developed that incorporates signal-fading and natural within-field variabilities. Estimates of the within-field and between-field coefficients of variation were obtained for each cover-type and compared with similar quantities derived from LANDSAT images of the same fields. The classification accuracy provided by LANDSAT alone, radar alone, and both sensors combined was investigated. The results indicate that the addition of radar to LANDSAT improves the classification accuracy by about 10; percentage-points when the classification is performed on a pixel basis and by about 15 points when performed on a field-average basis
Polyploidization delay in rat hepatocytes under liver growth inhibition by hypokinesia
A study of young rats, weighing 55 to 59 g, after being for 10 days in conditions of limited mobility, shows a retardation of body growth as well as that of liver growth. The decrease in the rate of growth is accompanied by a reduction of cell proliferation and by delay polyploidization of hepatocytes in the liver of experimental rats. The materials, methods, and results of research are discussed
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