3,194 research outputs found
Studies on the maize cold tolerance tests in the Martonvásár phytotron
The climatic conditions in Hungary and in the countries to which seed is exported
makes the study of maize cold tolerance and constant improvements in the cold tolerance
of Martonvásár hybrids especially important. An improvement in the early spring cold
tolerance of maize would allow it to be grown in more northern areas with a cooler
climate, while on traditional maize-growing areas the profitability of maize production
could be improved by earlier sowing, leading to a reduction in transportation and drying
costs and in diseases caused by Fusarium sp. The recognition of this fact led Martonvásár
researchers to start investigating this subject nearly four decades ago. The phytotron has
proved an excellent tool for studying and improving the cold tolerance of maize. The
review will give a brief summary of the results achieved in the field of maize cold
tolerance in the Martonvásár institute in recent decades
Time resolution below 100 ps for the SciTil detector of PANDA employing SiPM
The barrel time-of-flight (TOF) detector for the PANDA experiment at FAIR in
Darmstadt is planned as a scintillator tile hodoscope (SciTil) using 8000 small
scintillator tiles. It will provide fast event timing for a software trigger in
the otherwise trigger-less data acquisition scheme of PANDA, relative timing in
a multiple track event topology as well as additional particle identification
in the low momentum region. The goal is to achieve a time resolution of sigma ~
100 ps. We have conducted measurements using organic scintillators coupled to
Silicon Photomultipliers (SiPM). The results are encouraging such that we are
confident to reach the required time resolution.Comment: 10 pages, 7 figure
An all-sky Support Vector Machine selection of WISE YSO Candidates
We explored the AllWISE catalogue of the Wide-field Infrared Survey Explorer
mission and identified Young Stellar Object candidates. Reliable 2MASS and WISE
photometric data combined with Planck dust opacity values were used to build
our dataset and to find the best classification scheme. A sophisticated
statistical method, the Support Vector Machine (SVM) is used to analyse the
multi-dimensional data space and to remove source types identified as
contaminants (extragalactic sources, main sequence stars, evolved stars and
sources related to the interstellar medium). Objects listed in the SIMBAD
database are used to identify the already known sources and to train our
method. A new all-sky selection of 133,980 Class I/II YSO candidates is
presented. The estimated contamination was found to be well below 1% based on
comparison with our SIMBAD training set. We also compare our results to that of
existing methods and catalogues. The SVM selection process successfully
identified >90% of the Class I/II YSOs based on comparison with photometric and
spectroscopic YSO catalogues. Our conclusion is that by using the SVM, our
classification is able to identify more known YSOs of the training sample than
other methods based on colour-colour and magnitude-colour selection. The
distribution of the YSO candidates well correlates with that of the Planck
Galactic Cold Clumps in the Taurus--Auriga--Perseus--California region.Comment: 27 pages, 15 figures, 15 table
Geodynamics of SW-Pannonian inselbergs (Mecsek and Villany Mts., SW Hungary): inferences from a complex structural analysis.
Domain walls of ferroelectric BaTiO3 within the Ginzburg-Landau-Devonshire phenomenological model
Mechanically compatible and electrically neutral domain walls in tetragonal,
orthorhombic and rhombohedral ferroelectric phases of BaTiO3 are systematically
investigated in the framework of the phenomenological
Ginzburg-Landau-Devonshire (GLD) model with parameters of Ref. [Hlinka and
Marton, Phys. Rev. 74, 104104 (2006)]. Polarization and strain profiles within
domain walls are calculated numerically and within an approximation leading to
the quasi-one-dimensional analytic solutions applied previously to the
ferroelectric walls of the tetragonal phase [W. Cao and L.E. Cross, Phys. Rev.
44, 5 (1991)]. Domain wall thicknesses and energy densities are estimated for
all mechanically compatible and electrically neutral domain wall species in the
entire temperature range of ferroelectric phases. The model suggests that the
lowest energy walls in the orthorhombic phase of BaTiO3 are the 90-degree and
60-degree walls. In the rhombohedral phase, the lowest energy walls are the
71-degree and 109-degree walls. All these ferroelastic walls have thickness
below 1 nm except for the 90-degree wall in the tetragonal phase and the
60-degree S-wall in the orthorhombic phase, for which the larger thickness of
the order of 5 nm was found. The antiparallel walls of the rhombohedral phase
have largest energy and thus they are unlikely to occur. The calculation
indicates that the lowest energy structure of the 109-degree wall and few other
domain walls in the orthorhombic and rhombohedral phases resemble Bloch-like
walls known from magnetism.Comment: 12 pages, 9 figure
Concentration inequalities for random fields via coupling
We present a new and simple approach to concentration inequalities for
functions around their expectation with respect to non-product measures, i.e.,
for dependent random variables. Our method is based on coupling ideas and does
not use information inequalities. When one has a uniform control on the
coupling, this leads to exponential concentration inequalities. When such a
uniform control is no more possible, this leads to polynomial or
stretched-exponential concentration inequalities. Our abstract results apply to
Gibbs random fields, in particular to the low-temperature Ising model which is
a concrete example of non-uniformity of the coupling.Comment: New corrected version; 22 pages; 1 figure; New result added:
stretched-exponential inequalit
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