41,797 research outputs found
Ambiguities of theoretical parameters and CP/T violation in neutrino factories
We study the optimal setup for observation of the CP asymmetry in neutrino
factory experiments --- the baseline length, the muon energy and the analysis
method. First, we point out that the statistical quantity which has been used
in previous works doesn't represent the CP asymmetry. Then we propose the more
suitable quantity, , which is sensitive to the CP
asymmetry. We investigate the behavior of with ambiguities of
the theoretical parameters. The fake CP asymmetry due to the matter effect
increases with the baseline length and hence the error in the estimation of the
fake CP asymmetry grows with the baseline length due to the ambiguities of the
theoretical parameters. Namely, we lose the sensitivity to the genuine
CP-violation effect in longer baseline.Comment: 8pages, 2figures, Talk given by J. Sato at Joint U.S. / Japan
Workshop on New Initiatives in Muon Lepton Flavor Violation and Neutrino
Oscillation with High Intense Muon and Neutrino Sources, Honolulu, Hawaii,
2-6 Oct 200
Large Lepton Mixing in a Coset-space Family Unification on
We study a coset-space unification model for families based on . We find that qualitative structure of quark and lepton mass
matrices in this model describes very well the observation. We stress, in
particular, that the large mixing angle, , required for the atmospheric neutrino oscillation reported by the
SuperKamiokande collaboration, is naturally obtained, which is a consequence of
unparallel family structure in the present coset-space unification.Comment: 8 pages, Latex2
A human colonic crypt culture system to study regulation of stem cell-driven tissue renewal and physiological function
The intestinal epithelium is one of the most rapidly renewing tissues in the human body and fulfils vital physiological roles such as barrier function and transport of nutrients and fluid. Investigation of gut epithelial physiology in health and disease has been hampered by the lack of ex vivo models of the native human intestinal epithelium. Recently, remarkable progress has been made in defining intestinal stem cells and in generating intestinal organoid cultures. In parallel, we have developed a 3D culture system of the native human colonic epithelium that recapitulates the topological hierarchy of stem cell-driven tissue renewal and permits the physiological study of native polarized epithelial cells. Here we describe methods to establish 3D cultures of intact human colonic crypts and conduct real-time imaging of intestinal tissue renewal, cellular signalling, and physiological function, in conjunction with manipulation of gene expression by lentiviral or adenoviral transduction. Visualization of mRNA- and protein-expression patterns in cultured human colonic crypts, and cross-validation with crypts derived from fixed mucosal biopsies, is also described. Alongside studies using intestinal organoids, the near-native human colonic crypt culture model will help to bridge the gap that exists between investigation of colon cancer cell lines and/or animal (tissue) studies, and progression to clinical trials. To this end, the near native human colonic crypt model provides a platform to aid the development of novel strategies for the prevention of inflammatory bowel disease and cancer
Vortical amplification of magnetic field at inward shock of supernova remnant Cassiopeia A
We present an interpretation of the time variability of the -ray flux
recently reported from a multi-epoch campaign of years observations of the
supernova remnant Cassiopeia A by {\it Chandra}. We show for the first time
quantitatively that the keV non-thermal flux increase up to
traces the growth of the magnetic field due to vortical amplification mechanism
at a reflection inward shock colliding with inner overdensities. The fast
synchrotron cooling as compared with shock-acceleration time scale
qualitatively supports the flux decrease.Comment: 5 pages, 2 figures, PRL in pres
On the Magnetic Excitation Spectra of High Tc Cu Oxides up to the Energies far above the Resonance Energy
Magnetic excitation spectra c"(q,w) of YBa2Cu3Oy and La214 systems have been
studied. For La1.88Sr0.12CuO4, c"(q,w) have been measured up to ~30 meV and
existing data have been analyzed up to the energy w~150 meV by using the
phenomenological expression of the generalized magnetic susceptibility
c(q,w)=c0(q,w)/{1+J(q)c0(q,w)}, where c0(q,w) is the susceptibility of the
electrons without the exchange coupling J(q) among them. In the relatively low
energy region up to slightly above the resonance energy Er, it has been
reported by the authors' group that the expression can explain characteristics
of the q- and w-dependence of the spectra of YBa2Cu3Oy (YBCO or YBCOy). Here,
it is also pointed out that the expression can reproduce the rotation of four
incommensurate peaks of c"(q,w) within the a*-b* plane about (p/a, p/a) {or
so-called (p, p)} point by 45 degree, which occurs as w goes to the energy
region far above Er from E below Er. For La2-xSrxCuO4 and La2-xBaxCuO4,
agreements between the observed results and the calculations are less
satisfactory than for YBCO, indicating that we have to take account of the
existence of the "stripes" to consistently explain the observed c"(q,w) of
La214 system especially near x=1/8.Comment: 14 pages, 5 figure
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