2,861 research outputs found
Symmetric Textures in SO(10) and LMA Solution for Solar Neutrinos
We analyze a model based on SUSY SO(10) combined with SU(2) family symmetry
and symmetric mass matrices constructed by the authors recently. Previously,
only the parameter space for the LOW and vacuum oscillation (VO) solutions was
investigated. We indicate in this note the parameter space which leads to large
mixing angle (LMA) solution to the solar neutrino problem with a slightly
modified effective neutrino mass matrix. The symmetric mass textures arising
from the left-right symmetry breaking and the SU(2) symmetry breaking give rise
to very good predictions for the quark and lepton masses and mixing angles. The
prediction of our model for the |U_{e\nu_{3}}| element in the
Maki-Nakagawa-Sakata (MNS) matrix is close to the sensitivity of current
experiments; thus the validity of our model can be tested in the near future.
We also investigate the correlation between the |U_{e\nu_{3}}| element and
\tan^{2}\theta_{\odot} in a general two-zero neutrino mass texture.Comment: RevTeX4; 9 pages; 1 figur
Image Reconstruction with a LaBr3-based Rotational Modulator
A rotational modulator (RM) gamma-ray imager is capable of obtaining
significantly better angular resolution than the fundamental geometric
resolution defined by the ratio of detector diameter to mask-detector
separation. An RM imager consisting of a single grid of absorbing slats
rotating ahead of an array of a small number of position-insensitive detectors
has the advantage of fewer detector elements (i.e., detector plane pixels) than
required by a coded aperture imaging system with comparable angular resolution.
The RM therefore offers the possibility of a major reduction in instrument
complexity, cost, and power. A novel image reconstruction technique makes it
possible to deconvolve the raw images, remove sidelobes, reduce the effects of
noise, and provide resolving power a factor of 6 - 8 times better than the
geometric resolution. A 19-channel prototype RM developed in our laboratory at
Louisiana State University features 13.8 deg full-angle field of view, 1.9 deg
geometric angular resolution, and the capability of resolving sources to within
35' separation. We describe the technique, demonstrate the measured performance
of the prototype instrument, and describe the prospects for applying the
technique to either a high-sensitivity standoff gamma-ray imaging detector or a
satellite- or balloon-borne gamma-ray astronomy telescope.Comment: submitted to Nuclear Instrument & Methods, special edition: SORMA
2010 on June 16, 201
Маркерные иммунофенотипические признаки бластов при т-клеточном остром лимфобластном лейкозе у детей
Острые лимфобластные лейкозы (ОЛЛ) Т-клеточного происхождения у детей составляют около 12% среди всех ОЛЛ. Они отличаются чрезвычайно тяжелым клиническим течением и неблагоприятным прогнозом. По морфоцитохимическим признакам невозможно разграничить Т-клеточные ОЛЛ от В-клеточных, поэтому важным является определение иммунофенотипа бластных клеток. У 168 детей с ОЛЛ в возрасте от 1 года до 14 лет проведено иммунофенотипирование бластных клеток; Т-ОЛЛ выявлен у 23 больных. Выявлены особенности фенотипа бластных клеток при T-I, T-II и T-III подвариантах ОЛЛ у детей.T-lineage acute lymphoblastic leukaemias (ALL) represent approximately 12% of all ALL in children. They feature unfavorable prognosis and extraordinarily hard clinical course. T-cell ALL cannot be differentiated from B-cell ALL by morphocytochemical features; therefore, it is crucial to define the immunophenotype of blast cells. Immunophenotyping of blast cells in 168 children with ALL aged from 1 to 14 was carried out. In 23 patients T-ALL was revealed. Peculiarities of the immunophenotype of blast cells in T-I, T-II, and T-III subgroups of ALL were established in children
Thermal correction to the Casimir force, radiative heat transfer, and an experiment
The low-temperature asymptotic expressions for the Casimir interaction
between two real metals described by Leontovich surface impedance are obtained
in the framework of thermal quantum field theory. It is shown that the Casimir
entropy computed using the impedance of infrared optics vanishes in the limit
of zero temperature. By contrast, the Casimir entropy computed using the
impedance of the Drude model attains at zero temperature a positive value which
depends on the parameters of a system, i.e., the Nernst heat theorem is
violated. Thus, the impedance of infrared optics withstands the thermodynamic
test, whereas the impedance of the Drude model does not. We also perform a
phenomenological analysis of the thermal Casimir force and of the radiative
heat transfer through a vacuum gap between real metal plates. The
characterization of a metal by means of the Leontovich impedance of the Drude
model is shown to be inconsistent with experiment at separations of a few
hundred nanometers. A modification of the impedance of infrared optics is
suggested taking into account relaxation processes. The power of radiative heat
transfer predicted from this impedance is several times less than previous
predictions due to different contributions from the transverse electric
evanescent waves. The physical meaning of low frequencies in the Lifshitz
formula is discussed. It is concluded that new measurements of radiative heat
transfer are required to find out the adequate description of a metal in the
theory of electromagnetic fluctuations.Comment: 19 pages, 4 figures. svjour.cls is used, to appear in Eur. Phys. J.
Evaluation of African-bred maize germplasm lines for resistance to aflatoxin accumulation
Aflatoxins, produced by the fungus Aspergillus flavus, contaminate maize grain and threaten human food and feed safety. Plant resistance is considered the best strategy for reducing aflatoxin accumulation. Six maize germplasm lines, TZAR101–TZAR106, were released by the International Institute of Tropical Agriculture-Southern Regional Research Center (IITA-SRRC) maize breeding collaboration for use in African National Programs and U.S. maize breeding programs. The present investigation was conducted to evaluate aflatoxin reduction by these lines in a U.S. environment. As germplasm lines, resistance was demonstrated by the lines tested in 2010 and 2014 trials. In 2010, TZAR106 was among the lines with the lowest toxin accumulation, and in 2014, along with TZAR102, supported low aflatoxin. When evaluated as single cross hybrids in 2012, 2013 and 2014, several crosses involving IITA-SRRC lines accumulated low toxin. In 2012, TZAR103 × HBA1 was one of 4 lines with the lowest concentration of aflatoxin. In 2014, five IITA-SRRC hybrids were among the lowest with TZAR102 × Va35 and TZAR102 × LH132 being the two lowest. Results demonstrate significant aflatoxin reduction by IITA-SRRC lines in a U.S. aflatoxin-conducive environment (at Mississippi State University). Further testing in different locations and environments is needed to further evaluate the potential usefulness of these germplasm lines
All-optical thermal microscopy of laser-excited waveguides
We report on a unique combination of high-resolution confocal microscopy and ratiometric luminescence thermometry to obtain thermal images of 800 nm pumped ultrafast laser-inscribed waveguides in a Nd:YAG crystal. Thermal images evidence a strong localization of thermal load in the waveguide active volume. Comparison between experimental data and numerical simulations reveals that ultrafast laser-inscribed damage tracks in Nd:YAG crystals behave both as low-index and low-thermal conductivity barriersThis work was supported by the Spanish Ministerio de Economía y Competitividad (MINECO) under grants MAT2013-47395-C4-1-R and FIS2013-44174-P and from Junta de Castilla y León (Project SA116U13, UIC016
Violation of the Nernst heat theorem in the theory of thermal Casimir force between Drude metals
We give a rigorous analytical derivation of low-temperature behavior of the
Casimir entropy in the framework of the Lifshitz formula combined with the
Drude dielectric function. An earlier result that the Casimir entropy at zero
temperature is not equal to zero and depends on the parameters of the system is
confirmed, i.e. the third law of thermodynamics (the Nernst heat theorem) is
violated. We illustrate the resolution of this thermodynamical puzzle in the
context of the surface impedance approach by several calculations of the
thermal Casimir force and entropy for both real metals and dielectrics.
Different representations for the impedances, which are equivalent for real
photons, are discussed. Finally, we argue in favor of the Leontovich boundary
condition which leads to results for the thermal Casimir force that are
consistent with thermodynamics.Comment: 24 pages, 3 figures, accepted for publication in Phys. Rev.
Two-photon luminescence thermometry: towards 3D high-resolution thermal imaging of waveguides
We report on the use of the Erbium-based luminescence thermometry to realize high resolution, three dimensional (3D) thermal imaging of optical waveguides. Proof of concept is demonstrated in a 980-nm laser pumped ultrafast laser inscribed waveguide in Er:Yb phosphate glass. Multi-photon microscopy images revealed the existence of well confined intra-waveguide temperature increments as large as 200°C for moderate 980-nm pump powers of 120 mW. Numerical simulations and experimental data reveal that thermal loading can be substantially reduced if pump events are separated more than the characteristic thermal time that for the waveguides investigated is in the millisecond time scaleThis work has been supported by the Ministerio de Economía y Competitividad of Spain (MINECO) (FIS2013-44174-P, MAT2013-47395-C4-1-R) and National Natural Science Foundation of China (NSFC) (11274203
Longitudinal broadening of near side jets due to parton cascade
Longitudinal broadening along direction on near side in
two-dimensional () di-hadron correlation
distribution has been studied for central Au+Au collisions at =
200 GeV, within a dynamical multi-phase transport model. It was found that the
longitudinal broadening is generated by a longitudinal flow induced by strong
parton cascade in central Au+Au collisions, in comparison with p+p collisions
at = 200 GeV. The longitudinal broadening may shed light on the
information about strongly interacting partonic matter at RHIC.Comment: 5 pages, 4 figures; accepted by Eur. Phys. J.
Surface-impedance approach solves problems with the thermal Casimir force between real metals
The surface impedance approach to the description of the thermal Casimir
effect in the case of real metals is elaborated starting from the free energy
of oscillators. The Lifshitz formula expressed in terms of the dielectric
permittivity depending only on frequency is shown to be inapplicable in the
frequency region where a real current may arise leading to Joule heating of the
metal. The standard concept of a fluctuating electromagnetic field on such
frequencies meets difficulties when used as a model for the zero-point
oscillations or thermal photons in the thermal equilibrium inside metals.
Instead, the surface impedance permits not to consider the electromagnetic
oscillations inside the metal but taking the realistic material properties into
account by means of the effective boundary condition. An independent derivation
of the Lifshitz-type formulas for the Casimir free energy and force between two
metal plates is presented within the impedance approach. It is shown that they
are free of the contradictions with thermodynamics which are specific to the
usual Lifshitz formula for dielectrics in combination with the Drude model. We
demonstrate that in the impedance approach the zero-frequency contribution is
uniquely fixed by the form of impedance function and does not need any of the
ad hoc prescriptions intensively discussed in the recent literature. As an
example, the computations of the Casimir free energy between two gold plates
are performed at different separations and temperatures. It is argued that the
surface impedance approach lays a reliable framework for the future
measurements of the thermal Casimir force.Comment: 21 pages, 3 figures, to appear in Phys. Rev.
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