19,591 research outputs found
Discrimination of the light CP-odd scalars between in the NMSSM and in the SLHM
The presence of the light CP-odd scalar boson predicted in the
next-to-minimal supersymmetric model (NMSSM) and the simplest little Higgs
model (SLHM) dramatically changes the phenomenology of the Higgs sector. We
suggest a practical strategy to discriminate the underlying model of the CP-odd
scalar boson produced in the decay of the standard model-like Higgs boson. We
define the decay rate of "the non -tagged jet pair" with which we compute
the ratio of decay rates into lepton and jets. They show much different
behaviors between the NMSSM and the SLHM.Comment: 5 pages, 2 figures (5 figure files
Ammonia Imaging of the Disks in the NGC 1333 IRAS 4A Protobinary System
The NGC 1333 IRAS 4A protobinary was observed in the ammonia (2, 2) and (3,
3) lines and in the 1.3 cm continuum with a high resolution (about 1.0 arcsec).
The ammonia maps show two compact sources, one for each protostar, and they are
probably protostellar accretion disks. The disk associated with IRAS 4A2 is
seen nearly edge-on and shows an indication of rotation. The A2 disk is
brighter in the ammonia lines but dimmer in the dust continuum than its sibling
disk, with the ammonia-to-dust flux ratios different by about an order of
magnitude. This difference suggests that the twin disks have surprisingly
dissimilar characters, one gas-rich and the other dusty. The A2 disk may be
unusually active or hot, as indicated by its association with water vapor
masers. The existence of two very dissimilar disks in a binary system suggests
that the formation process of multiple systems has a controlling agent lacking
in the isolated star formation process and that stars belonging to a multiple
system do not necessarily evolve in phase with each other
Temperature- and magnetic-field-dependent resistivity of MgB2 sintered at high temperature and high pressure condition
We report the temperature- and magnetic-field-dependent resistivity of MgB2
sintered at high temperature and high pressure condition. The superconducting
transition width for the resistivity measurement was about 0.4 K, and the
low-field magnetization showed a sharp superconducting transition with a
transition width of about 1 K. The resistivity in the normal state roughly
followed T^2 behavior with smaller residual resistivity ratio (RRR) of 3 over
broad temperature region above 100 K rather than reported T^3 behavior with
larger RRR value of ~ 20 in the samples made at lower pressures. Also, the
resistivity did not change appreciably with the applied magnetic field, which
was different from previous report. These differences were discussed with the
microscopic and structural change due to the high-pressure sintering.Comment: 2 pages, 3 figures. Accepted by Physica
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Bisphosphonate inhibits the expression of cyclin A2 at the transcriptional level in normal human oral keratinocytes.
Nitrogen-containing bisphosphonates (N-BPs) are the most widely used anti-resorptive agents in the treatment of bone-related diseases. N-BPs inhibit bone resorption by specifically targeting osteoclasts, bone-resorbing cells. However, soft tissue toxicity, such as oral or gastrointestinal (GI) ulcerations has frequently been reported in N-BP users, suggesting that N-BPs may also directly target cells other than osteoclasts. Previously, we reported that BPs inhibit proliferation without inducing the apoptosis of normal human oral keratinocytes (NHOKs). However, the molecular mechanisms through which N-BPs inhibit the proliferation of NHOKs are not yet fully understood. In this study, we performed gene expression profiling in N-BP-treated NHOKs and identified cyclin A2 as one of the most commonly downregulated genes. When the NHOKs were treated with N-BPs, we found that the level of cyclin A2 was suppressed in a dose- and time-dependent manner. In addition, the protein level of cyclin A2 was also significantly lower in oral epithelial cells in N-BP-treated oral mucosal tissue constructs. Cyclin A2 promoter reporter assay revealed that N-BPs inhibited the luciferase activity, indicating that the inhibition of cyclin A2 expression occurs at the transcriptional level. Furthermore, N-BPs did not alter the expression of cyclin A2 in normal human oral fibroblasts (NHOFs), suggesting that the effect of N-BPs on cyclin A2 expression may be cell-type specific. Thus, the findings of our study demonstrate that the inhibition of NHOK proliferation by N-BPs is mediated, at least in part, by the suppression of cyclin A2 expression at the transcriptional level, which may explain the underlying mechanisms of soft tissue toxicity by N-BPs
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