1,456 research outputs found
Microcanonical Jet-fragmentation in proton-proton collisions at LHC Energy
In this paper, we show that the distribution of the longitudinal momentum
fraction of charged hadrons inside jets stemming from proton-proton
collisions at = 7 TeV center of mass energy can be described by a
statistical jet-fragmentation model. This model combines microcanonical
statistics and super-statistics induced by multiplicity fluctuations. The
resulting scale dependence of the parameters of the model turns out to be
similar to what was observed in electron-positron annihilations in Urmossy,
Barnaf\"oldi, and Bir\'o.Comment: 7 pages, 8 figure
Simultaneous Diagonal and Off Diagonal Order in the Bose--Hubbard Hamiltonian
The Bose-Hubbard model exhibits a rich phase diagram consisting both of
insulating regimes where diagonal long range (solid) order dominates as well as
conducting regimes where off diagonal long range order (superfluidity) is
present. In this paper we describe the results of Quantum Monte Carlo
calculations of the phase diagram, both for the hard and soft core cases, with
a particular focus on the possibility of simultaneous superfluid and solid
order. We also discuss the appearance of phase separation in the model. The
simulations are compared with analytic calculations of the phase diagram and
spin wave dispersion.Comment: 28 pages plus 24 figures, uuencoded Revtex+postscript file
Interaction between androgen receptor and coregulator SLIRP is regulated by Ack1 tyrosine kinase and androgen
Aberrant activation of the androgen receptor (AR) may play a critical role in castration resistant prostate cancer. After ligand binding, AR is recruited to the androgen responsive element (ARE) sequences on the DNA where AR interaction with coactivators and corepressors modulates transcription. We demonstrated that phosphorylation of AR at Tyr-267 by Ack1/TNK2 tyrosine kinase results in nuclear translocation, DNA binding, and androgen-dependent gene transcription in a low androgen environment. In order to dissect downstream mechanisms, we searched for proteins whose interaction with AR was regulated by Ack1. SLIRP (SRA stem-loop interacting RNA binding protein) was identified as a candidate protein. Interaction between AR and SLIRP was disrupted by Ack1 kinase activity as well as androgen or heregulin treatment. The noncoding RNA, SRA, was required for AR-SLIRP interaction. SLIRP was bound to AREâs of AR target genes in the absence of androgen. Treatment with androgen or heregulin led to dissociation of SLIRP from the ARE. Whole transcriptome analysis of SLIRP knockdown in androgen responsive LNCaP cells showed that SLIRP affects a significant subset of androgen-regulated genes. Our data suggest that Ack1 kinase and androgen regulate interaction between AR and SLIRP and that SLIRP functions as a coregulator of AR with properties of a corepressor in a context-dependent manner
Sub-barrier capture with quantum diffusion approach: actinide-based reactions
With the quantum diffusion approach the behavior of capture cross sections
and mean-square angular momenta of captured systems are revealed in the
reactions with deformed nuclei at subbarrier energies. The calculated results
are in a good agreement with existing experimental data. With decreasing
bombarding energy under the barrier the external turning point of the
nucleusnucleus potential leaves the region of short-range nuclear interaction
and action of friction. Because of this change of the regime of interaction, an
unexpected enhancement of the capture cross section is expected at bombarding
energies far below the Coulomb barrier. This effect is shown its worth in the
dependence of mean-square angular momentum of captured system on the bombarding
energy. From the comparison of calculated and experimental capture cross
sections, the importance of quasifission near the entrance channel is shown for
the actinide-based reactions leading to superheavy nuclei.Comment: 11 pages, 16 figures, Regular Articl
Four-point Functions of Lowest Weight CPOs in N=4 SYM_4 in Supergravity Approximation
We show that the recently found quartic action for the scalars from the
massless graviton multiplet of type IIB supergravity compactified on
AdS_5\times S^5 background coincides with the relevant part of the action of
the gauged N=8 5d supergravity on AdS_5. We then use this action to compute the
4-point function of the lowest weight chiral primary operators
\tr(\phi^{(i}\phi^{j)}) in N=4 SYM_4 at large and at strong `t Hooft
coupling.Comment: Latex, 21p, misprints are correcte
Stars in five dimensional Kaluza Klein gravity
In the five dimensional Kaluza Klein (KK) theory there is a well known class
of static and electromagnetic--free KK--equations characterized by a naked
singularity behavior, namely the Generalized Schwarzschild solution (GSS). We
present here a set of interior solutions of five dimensional KK--equations.
These equations have been numerically integrated to match the GSS in the
vacuum. The solutions are candidates to describe the possible interior perfect
fluid source of the exterior GSS metric and thus they can be models for stars
for static, neutral astrophysical objects in the ordinary (four dimensional)
spacetime.Comment: 15 pages, 8 figures. To be published in EPJ
Nucleon Axial Form Factor from Lattice QCD
Results for the isovector axial form factors of the proton from a lattice QCD
calculation are presented for both point-split and local currents. They are
obtained on a quenched lattice at with Wilson
fermions for a range of quark masses from strange to charm. We determine the
finite lattice renormalization for both the local and point-split currents of
heavy quarks. Results extrapolated to the chiral limit show that the
dependence of the axial form factor agrees reasonably well with experiment. The
axial coupling constant calculated for the local and the point-split
currents is about 6\% and 12\% smaller than the experimental value
respectively.Comment: 8 pages, 5 figures (included in part 2), UK/93-0
Critical Behavior of the Supersolid transition in Bose-Hubbard Models
We study the phase transitions of interacting bosons at zero temperature
between superfluid (SF) and supersolid (SS) states. The latter are
characterized by simultaneous off-diagonal long-range order and broken
translational symmetry. The critical phenomena is described by a
long-wavelength effective action, derived on symmetry grounds and verified by
explicit calculation. We consider two types of supersolid ordering:
checkerboard (X) and collinear (C), which are the simplest cases arising in two
dimensions on a square lattice. We find that the SF--CSS transition is in the
three-dimensional XY universality class. The SF--XSS transition exhibits
non-trivial new critical behavior, and appears, within a
expansion to be driven generically first order by fluctuations. However, within
a one--loop calculation directly in a strong coupling fixed point with
striking ``non-Bose liquid'' behavior is found. At special isolated
multi-critical points of particle-hole symmetry, the system falls into the 3d
Ising universality class.Comment: RevTeX, 24 pages, 16 figures. Also available at
http://www.cip.physik.tu-muenchen.de/tumphy/d/T34/Mitarbeiter/frey.htm
Oscillations of a solid sphere falling through a wormlike micellar fluid
We present an experimental study of the motion of a solid sphere falling
through a wormlike micellar fluid. While smaller or lighter spheres quickly
reach a terminal velocity, larger or heavier spheres are found to oscillate in
the direction of their falling motion. The onset of this instability correlates
with a critical value of the velocity gradient scale
s. We relate this condition to the known complex rheology of wormlike
micellar fluids, and suggest that the unsteady motion of the sphere is caused
by the formation and breaking of flow-induced structures.Comment: 4 pages, 4 figure
- âŠ