1,546 research outputs found
Statistically Significant Pattern Mining with Ordinal Utility
Statistically significant patterns mining (SSPM) is an essential and
challenging data mining task in the field of knowledge discovery in databases
(KDD), in which each pattern is evaluated via a hypothesis test. Our study aims
to introduce a preference relation into patterns and to discover the most
preferred patterns under the constraint of statistical significance, which has
never been considered in existing SSPM problems. We propose an iterative
multiple testing procedure that can alternately reject a hypothesis and safely
ignore the hypotheses that are less useful than the rejected hypothesis. One
advantage of filtering out patterns with low utility is that it avoids
consumption of the significance budget by rejection of useless (that is,
uninteresting) patterns. This allows the significance budget to be focused on
useful patterns, leading to more useful discoveries.
We show that the proposed method can control the familywise error rate (FWER)
under certain assumptions, that can be satisfied by a realistic problem class
in SSPM.\@We also show that the proposed method always discovers a set of
patterns that is at least equally or more useful than those discovered using
the standard Tarone-Bonferroni method SSPM.\@Finally, we conducted several
experiments with both synthetic and real-world data to evaluate the performance
of our method. As a result, in the experiments with real-world datasets, the
proposed method discovered a larger number of more useful patterns than the
existing method for all five conducted tasks.Comment: Proceedings of the 26th ACM SIGKDD Conference on Knowledge Discovery
and Data Mining (KDD '20), August 23--27, 2020, Virtual Event, CA, US
Coexistence of Superconductivity and Antiferromagnetism in Multilayered High- Superconductor HgBaCaCuO: A Cu-NMR Study
We report a coexistence of superconductivity and antiferromagnetism in
five-layered compound HgBaCaCuO (Hg-1245) with K,
which is composed of two types of CuO planes in a unit cell; three inner
planes (IP's) and two outer planes (OP's). The Cu-NMR study has revealed that
the optimallydoped OP undergoes a superconducting (SC) transition at
K, whereas the three underdoped IP's do an antiferromagnetic (AF) transition
below 60 K with the Cu moments of . Thus bulk
superconductivity with a high value of K and a static AF ordering at
K are realized in the alternating AF and SC layers. The AF-spin
polarization at the IP is found to induce the Cu moments of at
the SC OP, which is the AF proximity effect into the SC OP.Comment: 6 pages, 8 figure
Landau Theory of the Phase Transitions in Half Doped Manganites: Interplay of Magnetic, Charge and Structural Orders
The order parameters of the magnetic, charge and structural orders at
half-doped manganites are identified. A corresponding Landau theory of the
phase transitions is formulated. Many structural and thermodynamical behaviors
are accounted for and clarified within the framework. In particular, the theory
provides a unified picture for the scenario of the phase transitions and their
nature with respect to the variation of the tolerance factor of the manganites.
It also accounts for the origin of the incommensurate nature of the orbital
order and its subsequently accompanying antiferromagnetic order.Comment: 4 pages, 3 eps figures, Revtex, Phys. Rev. B61, 200
Phase diagram of a generalized Hubbard model applied to orbital order in manganites
The magnetic phase diagram of a two-dimensional generalized Hubbard model
proposed for manganites is studied within Hartree-Fock approximation. In this
model the hopping matrix includes anisotropic diagonal hopping matrix elements
as well as off-diagonal elements. The antiferromagnetic (AF), ferromagnetic
(F), canted (C) and paramagnetic (P) states are included in the analysis as
possible phases. It is found that away from half-filling only the canted and F
states may exist and AF and P states which are possible for the usual Hubbard
model do not appear. This is because the F order has already developed for
on-site repulsion U=0 due to the hopping matrix of the generalized model. When
applied for manganites the orbital degree is described by a pseudospin. Thus
our ``magnetic'' phase diagram obtained physically describes how orbital order
changes with and with doping for manganites. Part of our results are
consistent with other numerical calculations and some experiments.Comment: 5 eps figures; a note added, to appear in Phys. Rev.
Signatures of the excitonic memory effects in four-wave mixing processes in cavity polaritons
We report the signatures of the exciton correlation effects with finite
memory time in frequency domain degenerate four-wave mixing (DFWM) in
semiconductor microcavity. By utilizing the polarization selection rules, we
discriminate instantaneous, mean field interactions between excitons with the
same spins, long-living correlation due to the formation of biexciton state by
excitons with opposite spins, and short-memory correlation effects in the
continuum of unbound two-exciton states. The DFWM spectra give us the relative
contributions of these effects and the upper limit for the time of the
exciton-exciton correlation in the unbound two-exciton continuum. The obtained
results reveal the basis of the cavity polariton scattering model for the DFWM
processes in high-Q GaAs microcavity.Comment: 11 pages, 1 figur
Hole-doping dependence of percolative phase separation in Pr_(0.5-delta)Ca_(0.2+delta)Sr_(0.3)MnO_(3) around half doping
We address the problem of the percolative phase separation in polycrystalline
samples of PrCaSrMnO for (hole doping between 0.46 and 0.54). We perform
measurements of X-ray diffraction, dc magnetization, ESR, and electrical
resistivity. These samples show at a paramagnetic (PM) to ferromagnetic
(FM) transition, however, we found that for there is a coexistence of
both of these phases below . On lowering below the charge-ordering
(CO) temperature all the samples exhibit a coexistence between the FM
metallic and CO (antiferromagnetic) phases. In the whole range the FM phase
fraction () decreases with increasing . Furthermore, we show that only
for the metallic fraction is above the critical percolation
threshold . As a consequence, these samples show very
different magnetoresistance properties. In addition, for we
observe a percolative metal-insulator transition at , and for
the insulating-like behavior generated by the enlargement of
with increasing is well described by the percolation law , where is a critical exponent. On the basis of
the values obtained for this exponent we discuss different possible percolation
mechanisms, and suggest that a more deep understanding of geometric and
dimensionality effects is needed in phase separated manganites. We present a
complete vs phase diagram showing the magnetic and electric properties
of the studied compound around half doping.Comment: 9 text pages + 12 figures, submitted to Phys. Rev.
Charge Imbalance Effects on Interlayer Hopping and Fermi Surfaces in Multilayered High-T_c Cuprates
We study doping dependence of interlayer hoppings, t_\perp, in multilayered
cuprates with four or more CuO_2 planes in a unit cell. When the double
occupancy is forbidden in the plane, an effective amplitude of t_\perp in the
Gutzwiller approximation is shown to be proportional to the square root of the
product of doping rates in adjacent two planes, i.e., t^eff_\perp \propto
t_\perp \sqrt{\delta_1\delta_2}, where \delta_1 and \delta_2 represent the
doping rates of the two planes. More than three-layered cuprates have two kinds
of \cuo planes, i.e., inner- and outer planes (IP and OP), resulting in two
different values of t^eff_{\perp}, i.e., t^eff_\perp 1 \propto t_\perp
\sqrt{\delta_IP \delta_IP} between IP's, and t^eff_\perp 2 \propto t_\perp
\sqrt{\delta_IP \delta_OP} between IP and OP. Fermi surfaces are calculated in
the four-layered t-t'-t''-J model by the mean-field theory. The order
parameters, the renormalization factor of t_\perp, and the site-potential
making the charge imbalance between IP and OP are self-consistently determined
for several doping rates. We show the interlayer splitting of the Fermi
surfaces, which may be observed in the angle resolved photoemission
spectroscopy measurement.Comment: Some typographical errors are revised. Journal of Physical Society of
Japan, Vol.75, No.3, in pres
Long-term and age-dependent restoration of visual function in a mouse model of CNGB3-associated achromatopsia following gene therapy
Mutations in the CNGB3 gene account for >50% of all known cases of achromatopsia. Although of early onset, its stationary character and the potential for rapid assessment of restoration of retinal function following therapy renders achromatopsia a very attractive candidate for gene therapy. Here we tested the efficacy of an rAAV2/8 vector containing a human cone arrestin promoter and a human CNGB3 cDNA in CNGB3 deficient mice. Following subretinal delivery of the vector, CNGB3 was detected in both M- and S-cones and resulted in increased levels of CNGA3, increased cone density and survival, improved cone outer segment structure and normal subcellular compartmentalization of cone opsins. Therapy also resulted in long-term improvement of retinal function, with restoration of cone ERG amplitudes of up to 90% of wild-type and a significant improvement in visual acuity. Remarkably, successful restoration of cone function was observed even when treatment was initiated at 6 months of age; however, restoration of normal visual acuity was only possible in younger animals (e.g. 2–4 weeks old). This study represents achievement of the most substantial restoration of visual function reported to date in an animal model of achromatopsia using a human gene construct, which has the potential to be utilized in clinical trials
Interplay of spin and orbital ordering in the layered colossal magnetoresistance manganite La2-2xSr1+2xMn2O7 (0.5<=x<=1.0)
The crystallographic and magnetic phase diagram of the n=2 layered manganite
La2-2xSr1+2xMn2O7 in the region x=>0.5 has been studied using temperature
dependent neutron powder diffraction. The magnetic phase diagram reveals a
progression of ordered magnetic structures generally paralleling that of 3-D
perovskites with similar electronic doping: A (0.5 C
(0.75 G (0.90<=x<=1.0). However, the quasi-2-D structure
amplifies this progression to expose features of manganite physics uniquely
accessible in the layered systems: (a) a "frustrated" region between the A and
C regimes where no long-range magnetic order is observed; (b) magnetic
polytypism arising from weak inter-bilayer magnetic exchange in the Type-C
regime; and (c) a tetragonal to orthorhombic phase transition whose temperature
evolution directly measures ordering of d3y2-r2 orbitals in the a-b plane. This
orbital-ordering transition is precursory to Type-C magnetic ordering, where
ferromagnetic rods lie parallel to the b-axis. These observations support the
notion that eg orbital polarisation is the driving force behind magnetic spin
ordering. Finally, in the crossover region between Type-C and Type-G states, we
see some evidence for the development of local Type-C clusters embedded in a
Type-G framework, directly addressing proposals of similar short-range magnetic
ordering in highly-doped La1-xCaxMnO3 perovskites.Comment: 32 pages, 13 figures, submitted to Phys. Rev.
IFN-γ, IL-4 and IL-13 modulate responsiveness of human airway smooth muscle cells to IL-13
© 2008 Moynihan et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
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