20,164 research outputs found
Non-Minimal Quartic Inflation in Supersymmetric SO(10)
We describe how quartic () inflation with non-minimal
coupling to gravity is realized in realistic supersymmetric models. In
a well-motivated example the Higgs multiplets, which break
to and yield masses for the right-handed neutrinos, provide
the inflaton field . Thus, leptogenesis is a natural outcome in this
class of models. Moreover, the adjoint (45-plet) Higgs also acquires a
GUT scale value during inflation so that the monopole problem is evaded. The
scalar spectral index is in good agreement with the observations and ,
the tensor to scalar ratio, is predicted for realistic values of GUT parameters
to be of order .Comment: 10 pages, 1 figur
Optical Counterpart of the Ultraluminous X-ray Source IC 342 X-1
We present Chandra and HST observations of the ultraluminous X-ray source
(ULX) IC 342 X-1. The Chandra and HST images are aligned using two X-ray
emitting foreground stars. The astrometry corrected position for X-1 is R.A. =
03h45m55.61s, Decl. = +68d04m55.3s (J2000) with an error circle of 0.2". One
extended optical source is found in the error circle, which could be the
optical counterpart of X-1. The source shows an extended feature in HST images
at long wavelengths, which is likely to be a superposition of two point
sources, although it is possible that the dimmer one could be a jet. Both
sources are much redder than typical for ULX optical counterparts. The brighter
one has an absolute magnitude M_V = -5.2 +/- 0.2 and (B-V)_0 = 0.66 +/- 0.13
and the dimmer star is not detected in B and has (B-V)_0 > 2.1. Their colors
are consistent with an F8 to G0 Ib supergiant or a carbon star, respectively.
However, it is likely that part or most of the optical emission may be due to
X-rays reprocessed by the companion star or the accretion disk. The stellar
neighborhood of IC 342 X-1 lacks O stars and has a minimum age of ~10 Myr. This
excludes the possibility that the surrounding nebula is powered by an energetic
explosion of a single massive star that formed a black hole. We suggest that
the nebula is most likely powered by an outflow from the X-ray source.Comment: 10 pages, 8 figures, accepted for publication in Ap
Rescue with an anti-inflammatory peptide of chickens infected H5N1 avian flu
Chickens suffering from avian flu caused by H5N1 influenza virus are destined to die within 2 days due to a systemic inflammatory response. Since HVJ infection (1,2) and influenza virus infection (3,4) cause infected cells to activate homologous serum complement, the systemic inflammatory response elicited could be attributed to the unlimited generation of C5a anaphylatoxin of the complement system, which is a causative peptide of serious inflammation. In monkeys inoculated with a lethal dose of LPS (4 mg/kg body weight), inhibition of C5a by an inhibitory peptide termed AcPepA (5) rescued these animals from serious septic shock which would have resulted in death within a day (6). Therefore, we tested whether AcPepA could also have a beneficial effect on chickens with bird flu. On another front, enhanced production of endothelin-1 (ET-1) and the activation of mast cells (MCs) have been implicated in granulocyte sequestration (7). An endothelin receptor derived antisense homology box peptide (8) designated ETR-P1/fl was shown to antagonize endothelin A receptor (ET-A receptor) (9) and reduce such inflammatory responses as endotoxin-shock (10) and hemorrhagic shock (11), thereby suppressing histamine release in the circulation (12). Thus, we also administered ETR-P1/fl to bird flu chickens expecting suppression of a systemic inflammatory response
Diquark Higgs at LHC
Existence of color sextet diquark Higgs fields with TeV masses will indicate
a fundamentally different direction for unification than conventional grand
unified theories. There is a class of partial unification models based on the
gauge group that implement the seesaw
mechanism for neutrino mass with seesaw scale around GeV, where
indeed such light fields appear naturally despite the high gauge symmetry
breaking scale. They couple only to up-type quarks in this model.
We discuss phenomenological constraints on these fields and show that they
could be detected at LHC via their decay to either or single top + jet. We
also find that existing Tevatron data gives a lower bound on its mass somewhere
in the 400-500 GeV, for reasonable values of its coupling.Comment: 5 pages, 3 figure
Measurement of Plane Stress States using Electromagnetic-Acoustic Transducers
Assessment of structural safety requires knowledge of the shape of any defect and the stresses acting on it. Ultrasonics can be used to measure applied stress since there is a (small) change in velocity with stress. However the problem becomes more difficult when measuring residual stress. Here the influence of other factors such as variation in microstructure must be accounted for. For example, one method is to measure the percent difference in velocity of orthogonally polarized shear waves (the acoustic birefringence B). When the material symmetry and stress axes coincide [1], B=Bo+CaD where Be is the birefringence in the unstressed state, Ca is the acoustoelastic constant and D is the difference of principal stresses. The usual procedure is to measure B at a “reference” location where stresses are known, and assume homogeneity of microstructure
Bi-stability of mixed states in neural network storing hierarchical patterns
We discuss the properties of equilibrium states in an autoassociative memory
model storing hierarchically correlated patterns (hereafter, hierarchical
patterns). We will show that symmetric mixed states (hereafter, mixed states)
are bi-stable on the associative memory model storing the hierarchical patterns
in a region of the ferromagnetic phase. This means that the first-order
transition occurs in this ferromagnetic phase. We treat these contents with a
statistical mechanical method (SCSNA) and by computer simulation. Finally, we
discuss a physiological implication of this model. Sugase et al. analyzed the
time-course of the information carried by the firing of face-responsive neurons
in the inferior temporal cortex. We also discuss the relation between the
theoretical results and the physiological experiments of Sugase et al.Comment: 18 pages, 6 figure
Origin and Development of the Photogenic Organs of Lampyrids, with Special Reference to Those of Luciola cruciata MOTSCHULSKY and Pyrocœlia rufa Ern. OLIVIER
Momentum dependence of the energy gap in the superconducting state of optimally doped Bi2(Sr,R)2CuOy (R=La and Eu)
The energy gap of optimally doped Bi2(Sr,R)2CuOy (R=La and Eu) was probed by
angle resolved photoemission spectroscopy (ARPES) using a vacuum ultraviolet
laser (photon energy 6.994 eV) or He I resonance line (21.218 eV) as photon
source. The results show that the gap around the node at sufficiently low
temperatures can be well described by a monotonic d-wave gap function for both
samples and the gap of the R=La sample is larger reflecting the higher Tc.
However, an abrupt deviation from the d-wave gap function and an opposite R
dependence for the gap size were observed around the antinode, which represent
a clear disentanglement between the antinodal pseudogap and the nodal
superconducting gap.Comment: Submitted as the proceedings of LT2
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