21,088 research outputs found
Communication and equilibrium in discontinuous games of incomplete information
This paper offers a new approach to the study of economic problems usually modeled as games of incomplete information with discontinuous payoffs. Typically, the discontinuities arise from indeterminacies (ties) in the underlying problem. The point of view taken here is that the tie-breaking rules that resolve these indeterminacies should be viewed as part of the solution rather than part of the description of the model. A solution is therefore a tie-breaking rule together with strategies satisfying the usual best-response criterion. When information is incomplete, solutions need not exist; that is, there may be no tie-breaking rule that is compatible with the existence of strategy profiles satisfying the usual best-response criteria. It is shown that the introduction of incentive compatible communication (cheap talk) restores existence
A quantum Mermin--Wagner theorem for quantum rotators on two--dimensional graphs
This is the first of a series of papers considering symmetry properties of
quantum systems over 2D graphs or manifolds, with continuous spins, in the
spirit of the Mermin--Wagner theorem. In the model considered here (quantum
rotators) the phase space of a single spin is a dimensional torus, and
spins (or particles) are attached to sites of a graph satisfying a special
bi-dimensionality property. The kinetic energy part of the Hamiltonian is minus
a half of the Laplace operator. We assume that the interaction potential is
C-smooth and invariant under the action of a connected Lie group {\ttG}.
A part of our approach is to give a definition (and a construction) of a class
of infinite-volume Gibbs states for the systems under consideration (the class
\fG). This class contains the so-called limit Gibbs states, with or without
boundary conditions. We use ideas and techniques originated from various past
papers, in combination with the Feynman--Kac representation, to prove that any
state lying in the class \fG (defined in the text) is {\ttG}-invariant. An
example is given where the interaction potential is singular and there exists a
Gibbs state which is not {\ttG}-invariant.
In the next paper under the same title we establish a similar result for a
bosonic model where particles can jump from a vertex of the graph to one of its
neighbors (a generalized Hubbard model).Comment: 27 page
Magnetic resonance in the antiferromagnetic and normal state of NH_3K_3C_60
We report on the magnetic resonance of NH_3K_3C_60 powders in the frequency
range of 9 to 225 GHz. The observation of an antiferromagnetic resonance below
the phase transition at 40 K is evidence for an antiferromagnetically ordered
ground state. In the normal state, above 40 K, the temperature dependence of
the spin-susceptibilty measured by ESR agrees with previous static measurements
and is too weak to be explained by interacting localized spins in an insulator.
The magnetic resonance line width has an unusual magnetic-field dependence
which is large and temperature independent in the magnetically ordered state
and decreases rapidly above the transition. These observations agree with the
suggestion that NH_3K_3C_60 is a metal in the normal state and undergoes a
Mott-Hubbard metal to insulator transition at 40 K.Comment: 4 pages, 5 figures. Submitted to Phys. Rev.
Localization dynamics of fluids in random confinement
The dynamics of two-dimensional fluids confined within a random matrix of
obstacles is investigated using both colloidal model experiments and molecular
dynamics simulations. By varying fluid and matrix area fractions in the
experiment, we find delocalized tracer particle dynamics at small matrix area
fractions and localized motion of the tracers at high matrix area fractions. In
the delocalized region, the dynamics is subdiffusive at intermediate times, and
diffusive at long times, while in the localized regime, trapping in finite
pockets of the matrix is observed. These observations are found to agree with
the simulation of an ideal gas confined in a weakly correlated matrix. Our
results show that Lorentz gas systems with soft interactions are exhibiting a
smoothening of the critical dynamics and consequently a rounded
delocalization-to-localization transition.Comment: 5 pages, 3 figure
Entanglement conditions for two-mode states: Applications
We examine the implications of several recently derived conditions [Hillery
and Zubairy, Phys. Rev. Lett. 96, 050503 (2006)] for determining when a
two-mode state is entangled. We first find examples of non-Gaussian states that
satisfy these conditions. We then apply the entanglement conditions to the
study of several linear devices, the beam splitter, the parametric amplifier,
and the linear phase-insensitive amplifier. For the first two, we find
conditions on the input states that guarantee that the output states are
entangled. For the linear amplifier, we determine in the limit of high and no
gain, when an entangled input leads to an entangled output. Finally, we show
how application of two two-mode entanglement conditions to a three-mode state
can serve as a test of genuine three-mode entanglement.Comment: 7 pages, no figures, replaced with published versio
Optimal eigenvalues estimate for the Dirac operator on domains with boundary
We give a lower bound for the eigenvalues of the Dirac operator on a compact
domain of a Riemannian spin manifold under the \MIT bag boundary condition.
The limiting case is characterized by the existence of an imaginary Killing
spinor.Comment: 10 page
Random Surfing Without Teleportation
In the standard Random Surfer Model, the teleportation matrix is necessary to
ensure that the final PageRank vector is well-defined. The introduction of this
matrix, however, results in serious problems and imposes fundamental
limitations to the quality of the ranking vectors. In this work, building on
the recently proposed NCDawareRank framework, we exploit the decomposition of
the underlying space into blocks, and we derive easy to check necessary and
sufficient conditions for random surfing without teleportation.Comment: 13 pages. Published in the Volume: "Algorithms, Probability, Networks
and Games, Springer-Verlag, 2015". (The updated version corrects small
typos/errors
Development of a protocol for maintaining viability while shipping organoid-derived retinal tissue.
Retinal organoid technology enables generation of an inexhaustible supply of three-dimensional retinal tissue from human pluripotent stem cells (hPSCs) for regenerative medicine applications. The high similarity of organoid-derived retinal tissue and transplantable human fetal retina provides an opportunity for evaluating and modeling retinal tissue replacement strategies in relevant animal models in the effort to develop a functional retinal patch to restore vision in patients with profound blindness caused by retinal degeneration. Because of the complexity of this very promising approach requiring specialized stem cell and grafting techniques, the tasks of retinal tissue derivation and transplantation are frequently split between geographically distant teams. Delivery of delicate and perishable neural tissue such as retina to the surgical sites requires a reliable shipping protocol and also controlled temperature conditions with damage-reporting mechanisms in place to prevent transplantation of tissue damaged in transit into expensive animal models. We have developed a robust overnight tissue shipping protocol providing reliable temperature control, live monitoring of the shipment conditions and physical location of the package, and damage reporting at the time of delivery. This allows for shipping of viable (transplantation-competent) hPSC-derived retinal tissue over large distances, thus enabling stem cell and surgical teams from different parts of the country to work together and maximize successful engraftment of organoid-derived retinal tissue. Although this protocol was developed for preclinical in vivo studies in animal models, it is potentially translatable for clinical transplantation in the future and will contribute to developing clinical protocols for restoring vision in patients with retinal degeneration
Self-consistent massive disks in triaxial dark matter halos
Galactic disks in triaxial dark matter halos become deformed by the
elliptical potential in the plane of the disk in such a way as to counteract
the halo ellipticity. We develop a technique to calculate the equilibrium
configuration of such a disk in the combined disk-halo potential, which is
based on the method of Jog (2000) but accounts for the radial variation in both
the halo potential and the disk ellipticity. This crucial ingredient results in
qualitatively different behavior of the disk: the disk circularizes the
potential at small radii, even for a reasonably low disk mass. This effect has
important implications for proposals to reconcile cuspy halo density profiles
with low surface brightness galaxy rotation curves using halo triaxiality. The
disk ellipticities in our models are consistent with observational estimates
based on two-dimensional velocity fields and isophotal axis ratios.Comment: ApJ, in pres
Nucleotide sequence of the luxA gene of Vibrio harveyi and the complete amino acid sequence of the alpha subunit of bacterial luciferase
The nucleotide sequence of the 1.85-kilobase EcoRI fragment from Vibrio harveyi that was cloned using a mixed-sequence synthetic oligonucleotide probe (Cohn, D. H., Ogden, R. C., Abelson, J. N., Baldwin, T. O., Nealson, K. H., Simon, M. I., and Mileham, A. J. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 120-123) has been determined. The alpha subunit-coding region (luxA) was found to begin at base number 707 and end at base number 1771. The alpha subunit has a calculated molecular weight of 40,108 and comprises a total of 355 amino acid residues. There are 34 base pairs separating the start of the alpha subunit structural gene and a 669-base open reading frame extending from the proximal EcoRI site. At the 3' end of the luxA coding region there are 26 bases between the end of the structural gene and the start of the luxB structural gene. Approximately two-thirds of the alpha subunit was sequenced by protein chemical techniques. The amino acid sequence implied by the DNA sequence, with few exceptions, confirmed the chemically determined sequence. Regions of the alpha subunit thought to comprise the active center were found to reside in two discrete and relatively basic regions, one from around residues 100-115 and the second from around residues 280-295
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