1,676 research outputs found
How to construct a coordinate representation of a Hamiltonian operator on a torus
The dynamical system of a point particle constrained on a torus is quantized
\`a la Dirac with two kinds of coordinate systems respectively; the Cartesian
and toric coordinate systems. In the Cartesian coordinate system, it is
difficult to express momentum operators in coordinate representation owing to
the complication in structure of the commutation relations between canonical
variables. In the toric coordinate system, the commutation relations have a
simple form and their solutions in coordinate representation are easily
obtained with, furthermore, two quantum Hamiltonians turning up. A problem
comes out when the coordinate system is transformed, after quantization, from
the Cartesian to the toric coordinate system.Comment: 17 pages, LaTeX, 1 Figure included as a compressed uuencoded
postscript fil
Anti-deuteron beam study at J-PARC HEF K1.8 beam line
We performed a beam study at the K1.8 beam line of J-PARC
Hadron Experimental Facility. 1.8 GeV/ beam yield was
measured to be 0.30 0.04 counts/spill for 30 GeV 70
protons/spill irradiated on a 66 mm thick of gold target with the vertical slit
opening widths of 2.2 mm, 5 mm and 5 mm for intermediate focus (IFV), mass slit
1 (MS1) and 2 (MS2), respectively. Corresponding beam yield is
roughly estimated to be 0.3 Mcounts/spill for the same slit condition.
Then, the production ratio at extraction angle of 6
degrees is estimated to be . This is the first time measurement
of the beam yield and production
ratio at J-PARC. Further beam line tuning may increase the beam
yield.Comment: 13 pages, 9 figures, J-PARC HEF K1.8 beam line group technical repor
Polarization phenomena in hyperon-nucleon scattering
We investigate polarization observables in hyperon-nucleon scattering by
decomposing scattering amplitudes into spin-space tensors, where each component
describes scattering by corresponding spin-dependent interactions, so that
contributions of the interactions in the observables are individually
identified. In this way, for elastic scattering we find some linear
combinations of the observables sensitive to particular spin-dependent
interactions such as symmetric spin-orbit (LS) interactions and antisymmetric
LS ones. These will be useful to criticize theoretical predictions of the
interactions when the relevant observables are measured. We treat vector
analyzing powers, depolarizations, and coefficients of polarization transfers
and spin correlations, a part of which is numerically examined in scattering as an example. Total cross sections are studied for polarized
beams and targets as well as for unpolarized ones to investigate spin
dependence of imaginary parts of forward scattering amplitudes.Comment: 15 pages, 8 figure
Photoemission evidence for a Mott-Hubbard metal-insulator transition in VO
The temperature () dependent metal-insulator transition (MIT) in VO is
investigated using bulk sensitive hard x-ray ( 8 keV) valence band, core
level, and V 2 resonant photoemission spectroscopy (PES). The valence
band and core level spectra are compared with full-multiplet cluster model
calculations including a coherent screening channel. Across the MIT, V 3
spectral weight transfer from the coherent ( final)
states at Fermi level to the incoherent ( final)
states, corresponding to the lower Hubbard band, lead to gap-formation. The
spectral shape changes in V 1 and V 2 core levels as well as the valence
band are nicely reproduced from a cluster model calculations, providing
electronic structure parameters. Resonant-PES finds that the
states resonate across the V 2 threshold in
addition to the and states. The results support
a Mott-Hubbard transition picture for the first order MIT in VO.Comment: 6 pages, 3 figures. to be published in Phys. Rev.
Evidence for suppressed metallicity on the surface of La2-xSrxCuO4 and Nd2-xCexCuO4
Hard X-ray Photoemission spectroscopy (PES) of copper core electronic states,
with a probing depth of 60 \AA, is used to show that the Zhang-Rice
singlet feature is present in LaCuO but is absent in NdCuO.
Hole- and electron doping in LaSrCuO (LSCO) and
NdCeCuO (NCCO) result in new well-screened features which are
missing in soft X-ray PES. Impurity Anderson model calculations establish
metallic screening as its origin, which is strongly suppressed within 15
of the surface. Complemented with X-ray absorption spectroscopy,
the small chemical-potential shift in core levels ( eV) are shown to
be consistent with modifications of valence and conduction band states spanning
the band gap ( eV) upon hole- and electron-doping in LSCO and NCCO.Comment: 4 pages, 4 figure
Chlamydomonas DYX1C1/PF23 is essential for axonemal assembly and proper morphology of inner dynein arms
Cytoplasmic assembly of ciliary dyneins, a process known as preassembly, requires numerous non-dynein proteins, but the identities and functions of these proteins are not fully elucidated. Here, we show that the classical Chlamydomonas motility mutant pf23 is defective in the Chlamydomonas homolog of DYX1C1. The pf23 mutant has a 494 bp deletion in the DYX1C1 gene and expresses a shorter DYX1C1 protein in the cytoplasm. Structural analyses, using cryo-ET, reveal that pf23 axonemes lack most of the inner dynein arms. Spectral counting confirms that DYX1C1 is essential for the assembly of the majority of ciliary inner dynein arms (IDA) as well as a fraction of the outer dynein arms (ODA). A C-terminal truncation of DYX1C1 shows a reduction in a subset of these ciliary IDAs. Sucrose gradients of cytoplasmic extracts show that preassembled ciliary dyneins are reduced compared to wild-type, which suggests an important role in dynein complex stability. The role of PF23/DYX1C1 remains unknown, but we suggest that DYX1C1 could provide a scaffold for macromolecular assembly
Improved accuracy in estimation of left ventricular function parameters from QGS software with Tc-99m tetrofosmin gated-SPECT: a multivariate analysis.
The original publication is available at www.springerlink.com
authorThe purpose of this study was to verify whether the accuracy of left ventricular parameters related to left ventricular function from gated-SPECT improved or not, using multivariate analysis. METHODS: Ninety-six patients with cardiovascular diseases were studied. Gated-SPECT with the QGS software and left ventriculography (LVG) were performed to obtain left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume (ESV). Then, multivariate analyses were performed to determine empirical formulas for predicting these parameters. The calculated values of left ventricular parameters were compared with those obtained directly from the QGS software and LVG. RESULTS: Multivariate analyses were able to improve accuracy in estimation of LVEF, EDV and ESV. Statistically significant improvement was seen in LVEF (from r = 0.6965 to r = 0.8093, p < 0.05). Although not statistically significant, improvements in correlation coefficients were seen in EDV (from r = 0.7199 to r = 0.7595, p = 0.2750) and ESV (from r = 0.5694 to r = 0.5871, p = 0.4281). CONCLUSION: The empirical equations with multivariate analysis improved the accuracy in estimating LVEF from gated-SPECT with the QGS software
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