1,513 research outputs found
Measurement and display of control information. Remote manipulation and manual control Progress report, 1 Apr. - 30 Sep. 1967
Control interface between man and computer manipulators, and optimality of human controllers as time optimal, bang-bang state regulators of second order system
Conformal Quantum Mechanics in Two Black Hole Moduli Space
We discuss quantum mechanics in the moduli space consisting of two maximally
charged dilaton black holes. The quantum mechanics of the two black hole system
is similar to the one of DFF model, and this system has the conformal
symmetry. Also, we discuss the bound states in this system.Comment: 15 pages, RevTeX3.0. References added, Minor correction
Effects of an in-plane magnetic field on c-axis sum rule and superfluid density in high- cuprates
In layered cuprates, the application of an in-plane magnetic field changes the c-axis optical sum rule and superfluid density . For
pure incoherent c-axis coupling, has no effect on either quantities
but it does if an additional coherent component is present. For the coherent
contribution, different characteristic variations on and on
temperature result from the constant part of the hopping matrix
element and from the part which has zero on the diagonal of the
Brillouin zone. Only the constant part leads to a dependence on
the direction of as well as on its magnitude.Comment: 3 figure
Functional integral approach to multipoint correlators in 2d critical systems
We extend a previously developed technique for computing spin-spin critical
correlators in the 2d Ising model, to the case of multiple correlations. This
enables us to derive Kadanoff-Ceva's formula in a simple and elegant way. We
also exploit a doubling procedure in order to evaluate the critical exponent of
the polarization operator in the Baxter model. Thus we provide a rigorous proof
of the relation between different exponents, in the path-integral framework.Comment: 10 pages, LaTex, no figure
Quantization of maximally-charged slowly-moving black holes
We discuss the quantization of a system of slowly-moving extreme
Reissner-Nordstrom black holes. In the near-horizon limit, this system has been
shown to possess an SL(2,R) conformal symmetry. However, the Hamiltonian
appears to have no well-defined ground state. This problem can be circumvented
by a redefinition of the Hamiltonian due to de Alfaro, Fubini and Furlan (DFF).
We apply the Faddeev-Popov quantization procedure to show that the Hamiltonian
with no ground state corresponds to a gauge in which there is an obstruction at
the singularities of moduli space requiring a modification of the quantization
rules. The redefinition of the Hamiltonian a la DFF corresponds to a different
choice of gauge. The latter is a good gauge leading to standard quantization
rules. Thus, the DFF trick is a consequence of a standard gauge-fixing
procedure in the case of black hole scattering.Comment: Corrected errors in the gauge-fixing procedur
Statistical Mechanics of Charged Particles in Einstein-Maxwell-Scalar Theory
We consider an -body system of charged particle coupled to gravitational,
electromagnetic, and scalar fields. The metric on moduli space for the system
can be considered if a relation among the charges and mass is satisfied, which
includes the BPS relation for monopoles and the extreme condition for charged
black holes. Using the metric on moduli space in the long distance
approximation, we study the statistical mechanics of the charged particles at
low velocities. The partition function is evaluated as the leading order of the
large expansion, where is the spatial dimension of the system and will
be substituted finally as .Comment: 11 pages, RevTeX3.
Rapid glutamate receptor 2 trafficking during retinal degeneration
<p>Abstract</p> <p>Background</p> <p>Retinal degenerations, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), are characterized by photoreceptor loss and anomalous remodeling of the surviving retina that corrupts visual processing and poses a barrier to late-stage therapeutic interventions in particular. However, the molecular events associated with retinal remodeling remain largely unknown. Given our prior evidence of ionotropic glutamate receptor (iGluR) reprogramming in retinal degenerations, we hypothesized that the edited glutamate receptor 2 (GluR2) subunit and its trafficking may be modulated in retinal degenerations.</p> <p>Results</p> <p>Adult albino Balb/C mice were exposed to intense light for 24 h to induce light-induced retinal degeneration (LIRD). We found that prior to the onset of photoreceptor loss, protein levels of GluR2 and related trafficking proteins, including glutamate receptor-interacting protein 1 (GRIP1) and postsynaptic density protein 95 (PSD-95), were rapidly increased. LIRD triggered neuritogenesis in photoreceptor survival regions, where GluR2 and its trafficking proteins were expressed in the anomalous dendrites. Immunoprecipitation analysis showed interaction between KIF3A and GRIP1 as well as PSD-95, suggesting that KIF3A may mediate transport of GluR2 and its trafficking proteins to the novel dendrites. However, in areas of photoreceptor loss, GluR2 along with its trafficking proteins nearly vanished in retracted retinal neurites.</p> <p>Conclusions</p> <p>All together, LIRD rapidly triggers GluR2 plasticity, which is a potential mechanism behind functionally phenotypic revisions of retinal neurons and neuritogenesis during retinal degenerations.</p
Dynamics of Extreme Black Holes and Massive String States
In a recent paper, Duff and Rahmfeld argued that certain massive
states of the four-dimensional heterotic string correspond to extreme black
hole solutions. We provide further, dynamical, evidence for this identification
by comparing the scattering of these elementary string states with that of the
corresponding extreme black holes, in the limit of low velocities.Comment: 18 pages, harvma
Scaling of thermal conductivity of helium confined in pores
We have studied the thermal conductivity of confined superfluids on a
bar-like geometry. We use the planar magnet lattice model on a lattice with . We have applied open boundary conditions on the bar
sides (the confined directions of length ) and periodic along the long
direction. We have adopted a hybrid Monte Carlo algorithm to efficiently deal
with the critical slowing down and in order to solve the dynamical equations of
motion we use a discretization technique which introduces errors only
in the time step . Our results demonstrate the
validity of scaling using known values of the critical exponents and we
obtained the scaling function of the thermal resistivity. We find that our
results for the thermal resistivity scaling function are in very good agreement
with the available experimental results for pores using the tempComment: 5 two-column pages, 3 figures, Revtex
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