252 research outputs found
Evaluation of portacaval shunt patency with the differential glucose tolerance test.
A method has been described for establishing shunt patency by determining the difference in postprandial plasma glucose levels between a peripheral vein and the inferior vena cava at or near the site of the portal-systemic anastomosis. This tet was evaluated both in the laboratory with normal dogs before and after Eck fistula formation as well as cirrhotic patients with and without shunts. The results indicate that this test is reliable and has the advantages of safety, specificity, and ease of performance
Liquid behavior of cross-linked actin bundles
The actin cytoskeleton is a critical regulator of cytoplasmic architecture and mechanics, essential in a myriad of physiological processes. Here we demonstrate a liquid phase of actin filaments in the presence of the physiological cross-linker, filamin. Filamin condenses short actin filaments into spindle-shaped droplets, or tactoids, with shape dynamics consistent with a continuum model of anisotropic liquids. We find that cross-linker density controls the droplet shape and deformation timescales, consistent with a variable interfacial tension and viscosity. Near the liquid-solid transition, cross-linked actin bundles show behaviors reminiscent of fluid threads, including capillary instabilities and contraction. These data reveal a liquid droplet phase of actin, demixed from the surrounding solution and dominated by interfacial tension. These results suggest a mechanism to control organization, morphology, and dynamics of the actin cytoskeleton
New Gauged Linear Sigma Models for 8D HyperKahler Manifolds and Calabi-Yau Crystals
We propose two kinds of gauged linear sigma models whose moduli spaces are
real eight-dimensional hyperKahler and Calabi-Yau manifolds, respectively.
Here, hyperKahler manifolds have sp(2) holonomy in general and are dual to Type
IIB (p,q)5-brane configurations. On the other hand, Calabi-Yau fourfolds are
toric varieties expressed as quotient spaces. Our model involving fourfolds is
different from the usual one which is directly related to a symplectic quotient
procedure. Remarkable features in newly-found three-dimensional
Chern-Simons-matter theories appear here as well, such as dynamical
Fayet-Iliopoulos parameters, one dualized photon and its residual discrete
gauge symmetry.Comment: 20 pages, 1 figure; v2: minor changes and references added; v3:
statements improved, newer than JHEP versio
The Color-Octet intrinsic charm in and decays
Color-octet mechanism for the decay B\to \eta^\prime X is proposed to explain
the large branching ratio of Br(B\to \eta^\prime X)\sim 1\times 10^{-3}
recently announced by CLEO. We argue that the inclusive \eta^\prime production
in B decays may dominantly come from the Cabbibo favored b\to (\bar c c)_8s
process where \bar c c pair is in a color-octet configuration, and followed by
the nonperturbative transition (\bar c c)_8\to \eta^\prime X. The color-octet
intrinsic charm component in the higher Fock states of \eta^\prime is crucial
and is induced by the strong coupling of \eta^\prime to gluons via QCD axial
anomaly.Comment: 9 pages, RevTex, 1 PS figur
Baryon-Baryon Interactions
After a short survey of some topics of interest in the study of baryon-baryon
scattering, the recent Nijmegen energy dependent partial wave analysis (PWA) of
the nucleon-nucleon data is reviewed. In this PWA the energy range for both pp
and np is now 0 < Tlab < 350 MeV and a chi^2_{d.o.f.}=1.08 was reached. The
implications for the pion-nucleon coupling constants are discussed. Comments
are made with respect to recent discussions around this coupling constant in
the literature. In the second part, we briefly sketch the picture of the baryon
in several, more or less QCD-based, quark-models that have been rather
prominent in the literature. Inspired by these pictures we constructed a new
soft-core model for the nucleon-nucleon interaction and present the first
results of this model in a chi^2 -fit to the new multi-energy Nijmegen PWA.
With this new model we succeeded in narrowing the gap between theory and
experiment at low energies. For the energies Tlab = 25-320 MeV we reached a
record low chi^2_{p.d.p.} = 1.16. We finish the paper with some conclusions and
an outlook describing the extension of the new model to baryon-baryon
scattering.Comment: 12 pages LaTeX and one postscript figure included. Invited talk
presented at the XIVth European Conference of Few-Body Problems in Physics,
Amsterdam, August 23-28, 199
Glueball Interpretation of (2230)
On the basis of the results of
and , measured by the BES Collaboration in radiative J/ decays,
combined with the upper limit of Br()Br(), measured by PS185 experiment, we argue
that the distinctive properties of (2230), the flavor-symmetric decays and
the narrow partial decay widths to and as well as its
copious production in radiative J/ decay, would strongly favor the
glueball interpretation of (2230).Comment: Latex file, no figure
Genus-one correction to asymptotically free Seiberg-Witten prepotential from Dijkgraaf-Vafa matrix model
We find perfect agreements on the genus-one correction to the prepotential of
SU(2) Seiberg-Witten theory with N_f=2, 3 between field theoretical and
Dijkgraaf-Vafa-Penner type matrix model results.Comment: 12 pages; v2: minor revision; v3: more structured, submitted versio
Spacial and temporal dynamics of the volume fraction of the colloidal particles inside a drying sessile drop
Using lubrication theory, drying processes of sessile colloidal droplets on a
solid substrate are studied. A simple model is proposed to describe temporal
dynamics both the shape of the drop and the volume fraction of the colloidal
particles inside the drop. The concentration dependence of the viscosity is
taken into account. It is shown that the final shapes of the drops depend on
both the initial volume fraction of the colloidal particles and the capillary
number. The results of our simulations are in a reasonable agreement with the
published experimental data. The computations for the drops of aqueous solution
of human serum albumin (HSA) are presented.Comment: Submitted to EPJE, 7 pages, 8 figure
Holography of a Composite Inflaton
We study the time evolution of a brane construction that is holographically
dual to a strongly coupled gauge theory that dynamically breaks a global
symmetry through the generation of an effective composite Higgs vev. The D3/D7
system with a background magnetic field or non-trivial gauge coupling (dilaton)
profile displays the symmetry breaking. We study motion of the D7 brane in the
background of the D3 branes. For small field inflation in the field theory the
effective Higgs vev rolls from zero to the true vacuum value. We study what
phenomenological dilaton profile generates the slow rolling needed, hence
learning how the strongly coupled gauge theory's coupling must run. We note
that evolution of our configuration in the holographic direction, representing
the phyiscs of the strong interactions, can provide additional slowing of the
roll time. Inflation seems to be favoured if the coupling changes by only a
small amount or very gently. We speculate on how such a scenario could be
realized away from N=4 gauge theory, for example, in a walking gauge theory.Comment: 13 pages, 12 figures; v2: Added reference
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