38,337 research outputs found
Results of Orcein, C- and G-banding techniques in the Gayal (Bibos frontalis) and its crossbreds with European cattle (Bos taurus typicus)
International audienc
Hierarchical solutions of the Sherrington-Kirkpatrick model: Exact asymptotic behavior near the critical temperature
We analyze the replica-symmetry-breaking construction in the
Sherrington-Kirkpatrick model of a spin glass. We present a general scheme for
deriving an exact asymptotic behavior near the critical temperature of the
solution with an arbitrary number of discrete hierarchies of the broken replica
symmetry. We show that all solutions with finite-many hierarchies are unstable
and only the scheme with infinite-many hierarchies becomes marginally stable.
We show how the solutions from the discrete replica-symmetry-breaking scheme go
over to the continuous one with increasing the number of hierarchies.Comment: REVTeX4, 11 pages, no figure
Are the anti-charmed and bottomed pentaquarks molecular heptaquarks?
I study the charmed resonance D*p (3100) very recently
discovered by the H1 collaboration at Hera. An anticharmed resonance was
already predicted, in a recent publication mostly dedicated to the S=1
resonance Theta+(1540). To confirm these recent predictions, I apply the same
standard quark model with a quark-antiquark annihilation constrained by chiral
symmetry. I find that repulsion excludes the D*p (3100) as a
s-wave pentaquark. I explore the D*p (3100) as a heptaquark, equivalent to a
N-pi-D* linear molecule, with positive parity and total isospin I=0. I find
that the N-D repulsion is cancelled by the attraction existing in the N-pi and
pi-D channels. In our framework this state is harder to bind than the Theta+
described by a k-pi-N borromean bound-state, a lower binding energy is expected
in agreement with the H1 observation. Multiquark molecules N-pi-D, N-pi-B* and
N-pi-B are also predicted.Comment: 5 pages, 2 figures, RevTe
Eluate derived by extracorporal antibody-based immunoadsorption elevates the cytosolic Ca2+ concentration in podocytes via B-2 kinin receptors
Background/Aim: Patients with idiopathic focal segmental glomerulosclerosis (FSGS) often develop a recurrence of the disease after kidney transplantation. In a number of FSGS patients, plasmapheresis and immunoadsorption procedures have been shown to transiently reduce proteinuria and are thought to do this by eliminating a circulating factor. Direct cellular effects of eluates from immunoadsorption procedures on podocytes, the primary target of injury in FSGS, have not yet been reported. Methods: Eluates were derived from antibody-based immunoadsorption of a patient suffering from primary FSGS, a patient with systemic lupus erythematosus, and a healthy volunteer. The cytosolic free Ca2+ concentration ({[}Ca2+](i)) of differentiated podocytes was measured by single-cell fura-2 microfluorescence measurements. Free and total immunoreactive kinin levels were measured by radioimmunoassay. Results: FSGS eluates increased the {[}Ca2+](i) levels concentration dependently (EC50 0.14 mg/ml; n = 3-19). 1 mg/ml eluate increased the {[}Ca2+](i) values reversibly from 82 +/- 12 to 1,462 +/- 370 nmol/l, and then they returned back to 100 16 nmol/l (n = 19). The eluate-induced increase of {[}Ca2+](i) consisted of an initial Ca2+ peak followed by a Ca2+ plateau which depended on the extracellular Ca2+ concentration. The eluate-induced increase of {[}Ca2+](i) was inhibited by the specific B-2 kinin receptor antagonist Hoe 140 in a concentration-dependent manner (IC50 2.47 nmol/l). In addition, prior repetitive application of bradykinin desensitized the effect of eluate on {[}Ca2+](i). A colonic epithelial cell line not reacting to bradykinin did not respond to eluate either (n = 6). Similar to FSGS eluates, the eluate preparations of both the systemic lupus patient and the healthy volunteer led to a biphasic, concentration-dependent {[}Ca2+](i) increase in poclocytes which again was inhibited by Hoe 140. Free kinins were detected in all eluate preparations. Conclusion: The procedure of antibody-based immunoadsorption leads to kinin in the eluate which elevates the {[}Ca2+](i) level of podocytes via B-2 kinin receptors. Copyright (C) 2002 S. Karger AG, Basel
UV/IR duality in noncommutative quantum field theory
We review the construction of renormalizable noncommutative euclidean
phi(4)-theories based on the UV/IR duality covariant modification of the
standard field theory, and how the formalism can be extended to scalar field
theories defined on noncommutative Minkowski space.Comment: 12 pages; v2: minor corrections, note and references added;
Contribution to proceedings of the 2nd School on "Quantum Gravity and Quantum
Geometry" session of the 9th Hellenic School on Elementary Particle Physics
and Gravity, Corfu, Greece, September 13-20 2009. To be published in General
Relativity and Gravitatio
Critical Behavior of Light
Light is shown to exhibit critical and tricritical behavior in passive
mode-locked lasers with externally injected pulses. It is a first and unique
example of critical phenomena in a one-dimensional many body light-mode system.
The phase diagrams consist of regimes with continuous wave, driven para-pulses,
spontaneous pulses via mode condensation, and heterogeneous pulses, separated
by phase transition lines which terminate with critical or tricritical points.
Enhanced nongaussian fluctuations and collective dynamics are observed at the
critical and tricritical points, showing a mode system analog of the critical
opalescence phenomenon. The critical exponents are calculated and shown to
comply with the mean field theory, which is rigorous in the light system.Comment: RevTex, 5 pages, 3 figure
Free-induction decay and envelope modulations in a narrowed nuclear spin bath
We evaluate free-induction decay for the transverse components of a localized
electron spin coupled to a bath of nuclear spins via the Fermi contact
hyperfine interaction. Our perturbative treatment is valid for special
(narrowed) bath initial conditions and when the Zeeman energy of the electron
exceeds the total hyperfine coupling constant : . Using one unified
and systematic method, we recover previous results reported at short and long
times using different techniques. We find a new and unexpected modulation of
the free-induction-decay envelope, which is present even for a purely isotropic
hyperfine interaction without spin echoes and for a single nuclear species. We
give sub-leading corrections to the decoherence rate, and show that, in
general, the decoherence rate has a non-monotonic dependence on electron Zeeman
splitting, leading to a pronounced maximum. These results illustrate the
limitations of methods that make use of leading-order effective Hamiltonians
and re-exponentiation of short-time expansions for a strongly-interacting
system with non-Markovian (history-dependent) dynamics.Comment: 13 pages, 9 figure
Obtaining Stiffness Exponents from Bond-diluted Lattice Spin Glasses
Recently, a method has been proposed to obtain accurate predictions for
low-temperature properties of lattice spin glasses that is practical even above
the upper critical dimension, . This method is based on the observation
that bond-dilution enables the numerical treatment of larger lattices, and that
the subsequent combination of such data at various bond densities into a
finite-size scaling Ansatz produces more robust scaling behavior. In the
present study we test the potential of such a procedure, in particular, to
obtain the stiffness exponent for the hierarchical Migdal-Kadanoff lattice.
Critical exponents for this model are known with great accuracy and any
simulations can be executed to very large lattice sizes at almost any bond
density, effecting a insightful comparison that highlights the advantages -- as
well as the weaknesses -- of this method. These insights are applied to the
Edwards-Anderson model in with Gaussian bonds.Comment: corrected version, 10 pages, RevTex4, 12 ps-figures included; related
papers available a http://www.physics.emory.edu/faculty/boettcher
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