4,780 research outputs found
Linear Programming Relaxations for Goldreich's Generators over Non-Binary Alphabets
Goldreich suggested candidates of one-way functions and pseudorandom
generators included in . It is known that randomly generated
Goldreich's generator using -wise independent predicates with input
variables and output variables is not pseudorandom generator with
high probability for sufficiently large constant . Most of the previous
works assume that the alphabet is binary and use techniques available only for
the binary alphabet. In this paper, we deal with non-binary generalization of
Goldreich's generator and derives the tight threshold for linear programming
relaxation attack using local marginal polytope for randomly generated
Goldreich's generators. We assume that input
variables are known. In that case, we show that when , there is an
exact threshold
such
that for , the LP relaxation can determine
linearly many input variables of Goldreich's generator if
, and that the LP relaxation cannot determine
input variables of Goldreich's generator if
. This paper uses characterization of LP solutions by
combinatorial structures called stopping sets on a bipartite graph, which is
related to a simple algorithm called peeling algorithm.Comment: 14 pages, 1 figur
Novel Charge Order and Superconductivity in Two-Dimensional Frustrated Lattice at Quarter Filling
Motivated by the various physical properties observed in
-(BEDT-TTF)X, we study the ground state of extended Hubbard model
on two-dimensional anisotropic triangular lattice at 1/4-filling with
variational Monte Carlo method. It is shown that the nearest-neighbor Coulomb
interaction enhances the charge fluctuation and it induces the anomalous state
such as charge-ordered metallic state and the triplet next-nearest-neighbor
-wave superconductivity. We discuss the relation to the real materials and
propose the unified view of the family of -(BEDT-TTF)X.Comment: 4 pages, 5 figure
Phase Diagram of Spinless Fermions on an Anisotropic Triangular Lattice at Half-filling
The strong coupling phase diagram of the spinless fermions on the anisotropic
triangular lattice at half-filling is presented. The geometry of inter-site
Coulomb interactions rules the phase diagram. Unconventional charge ordered
phases are detected which are the recently reported pinball liquid and the
striped chains. Both are induced by the quantum dynamics out of classical
disordered states and afford extremely correlated metallic states and the
particular domain wall-type of excitations, respectively. The disorder once
killed by the quantum effect revives at the finite temperature, which is
discussed in the terms of the organic -ET.Comment: 4pages 6figure
Nonlinear Conduction by Melting of Stripe-Type Charge Order in Organic Conductors with Triangular Lattices
We theoretically discuss the mechanism for the peculiar nonlinear conduction
in quasi-two-dimensional organic conductors \theta-(BEDT-TTF)2X
[BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene] through the melting of
stripe-type charge order. An extended Peierls-Hubbard model attached to
metallic electrodes is investigated by a nonequilibrium Green's function
technique. A novel current-voltage characteristic appears in a coexistent state
of stripe-type and nonstripe 3-fold charge orders, where the applied bias melts
mainly the stripe-type charge order through the reduction of lattice
distortion, whereas the 3-fold charge order survives. These contrastive
responses of the two different charge orders are consistent with the
experimental observations.Comment: 5 pages, 4 figures, to appear in J. Phys. Soc. Jp
Skeletal open bite with amelogenesis imperfecta treated with compression osteogenesis : a case report
Background: We successfully treated a 37-year-old male who had skeletal open bite with severe amelogenesis imperfecta (AI) with orthodontics, compression osteogenesis, and prosthodontics.
Case presentation: The patient was diagnosed with severe anterior open bite caused by severe AI. Corticotomy was performed on both buccal and palatal sides of the molar regions, and anchor plates were placed onto the bilateral zygomatic buttress and the center of the hard palate. After corticotomy, posterior maxillary segments were moved 3.5 mm superiorly to correct skeletal open bite with elastic chains. After 8-month, overbite had decreased by 2.0 mm. After further 5 months of prosthodontic preparation, orthodontic appliances were removed, and provisional crowns were set on all teeth. The anterior open bite was corrected, and ideal occlusion with a Class I molar relationship was achieved. The upper first molars were intruded 3.5 mm, resulting in 3.0o counter-clockwise rotation of the mandible. The total active treatment period was 16 months. Acceptable occlusion with a good facial profile was well maintained throughout the 8-year retention period.
Conclusions: Our results indicate long-term stability after interdisciplinary treatment combining orthodontics, oral surgery, and prosthodontics in a patient with severe anterior open bite and AI
Purification and immunochemical characterization of alpha-fetoprotein from rat fetal serum and liver
Two alpha1-globulin bands of fetal serum with relative mobilities against bromophenol blue of 0.55 and 0.58 on 7% polyacrylamide gel electrophoresis reacted with a monospecific rabbit antiserum to alpha-fetoprotein (AFP). The former globulin band was clearly detected in the fetal liver supernatant. AFP was immunochemically purified from both the fetal serum and liver, and their electrophoretic and immunochemical properties were compared. Liver AFP purified by immunoadsorbent column yielded electrophoretic mobilities and relative amounts of the two electrophoretically distinct components identical with the purified serum AFP. The immunological reactivity of the two components of the purified preparations from serum and liver against the monospecific anti-AFP serum was also indistinguishable. After the removal of the sialic acid residues from purified serum and liver AFP by treatment with neuraminidase for 6 to 12 hr, disc electrophoretic patterns on 5% polyacrylamide gel and immunoelectrophoretic patterns of the treated AFP were found to be closely similar in both preparations. It may be possible to conclude that serum and liver AFP are structurally indistinguishable and probably identical.</p
The Origin of the Charge Ordering and Its Relevance to Superconductivity in -(BEDT-TTF)X: The Effect of the Fermi Surface Nesting and the Distant Electron-Electron Interactions
The origin of the charge ordering in organic compounds -(BEDT-TTF) ((SCN), Tl,Rb,Co, Cs,Zn) is studied using an extended
Hubbard model. Calculating the charge susceptibility within random phase
approximation (RPA), we find that the charge
ordering observed at relatively high temperatures can be considered as a
consequence of a cooperation between the Fermi surface nesting, controlled by
the hopping integral in the direction, and the electron-electron
interactions, where the distant (next nearest neighbor) interactions that have
not been taken into account in most of the previous studies play an important
role.Mean field analysis at T=0 also supports the RPA results, and further
shows that in the charge ordered state, some portions of the Fermi
surface remain ungapped and are nested with a nesting vector close to the
modulation wave vector of the horizontal stripe ordering observed at low
temperatures in (SCN). We further study the possibility of
superconductivity by taking into account the distant off-site repulsions and
the band structure corresponding to I, in which superconductivity is
experimentally observed. We find that there is a close competition between
-wave-like singlet pairing and -wave-like triplet pairing due
to a cooperation between the charge and the spin fluctuations. The present
analysis provides a possible unified understanding of the experimental phase
diagram of the -(BEDT-TTF) family, ranging from a charge ordered
insulator to a superconductor.Comment: 13 pages, 18 figures (Figs.5,6,7,14,15,18 compressed using jpeg2ps
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