365 research outputs found
Glucose modulation of ATP-sensitive K-currents in wild-type, homozygous and heterozygous glucokinase knock-out mice
G-flux and Spectral Divisors
We propose a construction of G-flux in singular elliptic Calabi-Yau fourfold
compactifications of F-theory, which in the local limit allow a spectral cover
description. The main tool of construction is the so-called spectral divisor in
the resolved Calabi-Yau geometry, which in the local limit reduces to the Higgs
bundle spectral cover. We exemplify the workings of this in the case of an E_6
singularity by constructing the resolved geometry, the spectral divisor and in
the local limit, the spectral cover. The G-flux constructed with the spectral
divisor is shown to be equivalent to the direct construction from suitably
quantized linear combinations of holomorphic surfaces in the resolved geometry,
and in the local limit reduces to the spectral cover flux.Comment: 30 page
The Algebraic Curve of 1-loop Planar N=4 SYM
The algebraic curve for the psu (2,2|4) quantum spin chain is determined from
the thermodynamic limit of the algebraic Bethe ansatz. The Hamiltonian of this
spin chain has been identified with the planar 1-loop dilatation operator of
N=4 SYM. In the dual AdS_5 x S^5 string theory, various properties of the data
defining the curve for the gauge theory are compared to the ones obtained from
semiclassical spinning-string configurations, in particular for the case of
strings on AdS_5 x S^1 and the su(2,2) spin chain agreement of the curves is
shown.Comment: 34 pages, 2 figures; harvmac (b); v3: discussion of fermionic roots
expanded, figure and references adde
On the plane-wave cubic vertex
The exact bosonic Neumann matrices of the cubic vertex in plane-wave
light-cone string field theory are derived using the contour integration
techniques developed in our earlier paper. This simplifies the original
derivation of the vertex. In particular, the Neumann matrices are written in
terms of \mu-deformed Gamma-functions, thus casting them into a form that
elegantly generalizes the well-known flat-space solution. The asymptotics of
the \mu-deformed Gamma-functions allow one to determine the large-\mu behaviour
of the Neumann matrices including exponential corrections. We provide an
explicit expression for the first exponential correction and make a conjecture
for the subsequent exponential correction terms.Comment: 26 pages, 1 figure; harvmac (b); v4: minor corrections in appendix
Theileria parasites subvert E2F signaling to stimulate leukocyte proliferation
Intracellular pathogens have evolved intricate mechanisms to subvert host cell signaling pathways and ensure their own propagation. A lineage of the protozoan parasite genus Theileria infects bovine leukocytes and induces their uncontrolled proliferation causing a leukemia-like disease. Given the importance of E2F transcription factors in mammalian cell cycle regulation, we investigated the role of E2F signaling in Theileria-induced host cell proliferation. Using comparative genomics and surface plasmon resonance, we identified parasite-derived peptides that have the sequence-specific ability to increase E2F signaling by binding E2F negative regulator Retinoblastoma-1 (RB). Using these peptides as a tool to probe host E2F signaling, we show that the disruption of RB complexes ex vivo leads to activation of E2F-driven transcription and increased leukocyte proliferation in an infection-dependent manner. This result is consistent with existing models and, together, they support a critical role of E2F signaling for Theileria-induced host cell proliferation, and its potential direct manipulation by one or more parasite proteins
A Hybrid Higgs
We construct composite Higgs models admitting a weakly coupled Seiberg dual
description. We focus on the possibility that only the up-type Higgs is an
elementary field, while the down-type Higgs arises as a composite hadron. The
model, based on a confining SQCD theory, breaks supersymmetry and electroweak
symmetry dynamically and calculably. This simultaneously solves the \mu/B_\mu
problem and explains the smallness of the bottom and tau masses compared to the
top mass. The proposal is then applied to a class of models where the same
confining dynamics is used to generate the Standard Model flavor hierarchy by
quark and lepton compositeness. This provides a unified framework for flavor,
supersymmetry breaking and electroweak physics. The weakly coupled dual is used
to explicitly compute the MSSM parameters in terms of a few microscopic
couplings, giving interesting relations between the electroweak and soft
parameters. The RG evolution down to the TeV scale is obtained and salient
phenomenological predictions of this class of "single-sector" models are
discussed.Comment: 56 pages, 7 figures, v2: discussion on FCNCs and references added,
v3: JHEP versio
Radiative Scalar Meson Decays in the Light-Front Quark Model
We construct a relativistic wavefunction for scalar mesons within the
framework of light-front quark model(LFQM). This scalar wavefunction is used to
perform relativistic calculations of absolute widths for the radiative decay
processes, and
which incorporate the effects of glueball-
mixing. The mixed physical states are assumed to be ,and
for which the flavor-glue content is taken from the mixing
calculations of other works. Since experimental data for these processes are
poor, our results are compared with those of a recent non-relativistic model
calculation. We find that while the relativistic corrections introduced by the
LFQM reduce the magnitudes of the decay widths by 50-70%, the relative
strengths between different decay processes are fairly well preserved. We also
calculate decay widths for the processes and
(0^{++})\to\gamma\gamm involving the light scalars and
to test the simple model of these mesons. Our results of
model for these processes are not quite consistent with well-established data,
further supporting the idea that and are not conventional
states.Comment: 10 pages, 4 figure
Theories of Class F and Anomalies
We consider the 6d (2,0) theory on a fibration by genus g curves, and
dimensionally reduce along the fiber to 4d theories with duality defects. This
generalizes class S theories, for which the fibration is trivial. The
non-trivial fibration in the present setup implies that the gauge couplings of
the 4d theory, which are encoded in the complex structures of the curve, vary
and can undergo S-duality transformations. These monodromies occur around 2d
loci in space-time, the duality defects, above which the fiber is singular. The
key role that the fibration plays here motivates refering to this setup as
theories of class F. In the simplest instance this gives rise to 4d N=4
Super-Yang-Mills with space-time dependent coupling that undergoes SL(2, Z)
monodromies. We determine the anomaly polynomial for these theories by pushing
forward the anomaly polynomial of the 6d (2,0) theory along the fiber. This
gives rise to corrections to the anomaly polynomials of 4d N=4 SYM and theories
of class S. For the torus case, this analysis is complemented with a field
theoretic derivation of a U(1) anomaly in 4d N=4 SYM. The corresponding anomaly
polynomial is tested against known expressions of anomalies for wrapped
D3-branes with varying coupling, which are known field theoretically and from
holography. Extensions of the construction to 4d N = 0 and 1, and 2d theories
with varying coupling, are also discussed.Comment: 54 pages, 1 figure, v2: added discussion of non-supersymmetric
extension, v3: version as appears in JHE
Analysis of the structural features of the C-terminus of GLUT1 that are required for transport catalytic activity
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