252 research outputs found
Continuum-discretized coupled-channels method for four-body breakup reactions
Development of the method of CDCC (Continuum-Discretized Coupled-Channels)
from the level of three-body CDCC to that of four-body CDCC is reviewed.
Introduction of the pseudo-state method based on the Gaussian expansion method
for discretizing the continuum states of two-body and three-body projectiles
plays an essential role in the development. Furthermore, introduction of the
complex-range Gaussian basis functions is important to improve the CDCC for
nuclear breakup so as to accomplish that for Coulomb and nuclear breakup. A
successful application of the four-body CDCC to He+C scattering at
18 and 229.8 MeV is reported.Comment: Latex file of revtex4 class, 14 pages, 10 figures. A talk given at
the Workshop on Reaction Mechanisms for Rare Isotope Beams, Michigan State
University, March 9-12, 2005 (to appear in an AIP Conference Proceedings
Continuum-discretized coupled-channels method for four-body nuclear breakup in He+C scattering
We propose a fully quantum-mechanical method of treating four-body nuclear
breakup processes in scattering of a projectile consisting of three
constituents, by extending the continuum-discretized coupled-channels method.
The three-body continuum states of the projectile are discretized by
diagonalizing the internal
Hamiltonian of the projectile with the Gaussian basis functions. For
He+C scattering at 18 and 229.8 MeV, the validity of the method is
tested by convergence of the elastic and breakup cross sections with respect to
increasing the number of the basis functions. Effects of the four-body breakup
and the Borromean structure of He on the elastic and total reaction cross
sections are discussed.Comment: 5 pages, 6 figures, uses REVTeX 4, submitted to Phys. Rev.
New treatment of breakup continuum in the method of continuum discretized coupled channels
A new method of pseudo-state discretization is proposed for the method of
continuum discretized coupled channels (CDCC) to deal with three-body breakup
processes. We propose real- and complex-range Gaussian bases for the
pseudo-state wave functions, and show that they form in good approximation a
complete set in the configuration space which is important for breakup
processes.
Continuous S-matrix elements are derived with the approximate completeness
from discrete ones calculated by CDCC.
Accuracy of the method is tested quantitatively for two realistic examples,
d+Ni scattering at 80 MeV and Li+Ca scattering at 156 MeV
with the satisfactory results. Possibility of application of the method to
four-body breakup processes is also discussed.Comment: 10 pages, 14 Postscript figures, uses REVTeX 4, submitted to Phys.
Rev.
Analyzing power for the proton elastic scattering from neutron-rich 6He nucleus
Vector analyzing power for the proton-6He elastic scattering at 71
MeV/nucleon has been measured for the first time, with a newly developed
polarized proton solid target working at low magnetic field of 0.09 T. The
results are found to be incompatible with a t-matrix folding model prediction.
Comparisons of the data with g-matrix folding analyses clearly show that the
vector analyzing power is sensitive to the nuclear structure model used in the
reaction analysis. The alpha-core distribution in 6He is suggested to be a
possible key to understand the nuclear structure sensitivity.Comment: 5 pages, 3 figures, accepted for publication as a Rapid Communication
in Physical Review
Primary parotid tuberculosis mimicking parotid neoplasm: a case report
<p>Abstract</p> <p>Introduction</p> <p>Tuberculosis of the parotid gland is a rare clinical entity which causes some difficulties in diagnosis because of the similarities in presentation to that of a neoplasm. Diagnosis mainly relies in the treating physician having a high index of suspicion. The diagnosis is generally overlooked by otolaryngologists and most cases are undergoing unnecessary surgery.</p> <p>Case presentation</p> <p>A 20-year-old male presented with a mass in the right parotid region. The mass had been present for one year. Physical examination revealed a mobile, non-tender mass occupying the superficial lobe of the right parotid gland. Radiologic investigations revealed a well-defined, solid, mass lesion located in the posterior part of the superficial lobe of the right parotid gland. A provisional diagnosis of a neoplasm of the parotid gland was made and a right superficial parotidectomy was performed. Histopathologic examination of the specimen was reported as tuberculosis of the parotid gland. The patient was commenced on antitubercular chemotherapy.</p> <p>Conclusion</p> <p>Although rare, tuberculosis should be kept in mind and considered in the differential diagnosis of patients presenting with a solitary tumor in the parotid gland in order to avoid unnecessary surgery.</p
Reaction mechanism and characteristics of T_{20} in d + ^3He backward elastic scattering at intermediate energies
For backward elastic scattering of deuterons by ^3He, cross sections \sigma
and tensor analyzing power T_{20} are measured at E_d=140-270 MeV. The data are
analyzed by the PWIA and by the general formula which includes virtual
excitations of other channels, with the assumption of the proton transfer from
^3He to the deuteron. Using ^3He wave functions calculated by the Faddeev
equation, the PWIA describes global features of the experimental data, while
the virtual excitation effects are important for quantitative fits to the
T_{20} data. Theoretical predictions on T_{20}, K_y^y (polarization transfer
coefficient) and C_{yy} (spin correlation coefficient) are provided up to GeV
energies.Comment: REVTEX+epsfig, 17 pages including 6 eps figs, to be published in
Phys. Rev.
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CatSperζ regulates the structural continuity of sperm Ca2+ signaling domains and is required for normal fertility
We report that the Gm7068 (CatSpere) and Tex40 (CatSperz) genes encode novel subunits of a 9-subunit CatSper ion channel complex. Targeted disruption of CatSperz reduces CatSper current and sperm rheotactic efficiency in mice, resulting in severe male subfertility. Normally distributed in linear quadrilateral nanodomains along the flagellum, the complex lacking CatSperζ is disrupted at ~0.8 μm intervals along the flagellum. This disruption renders the proximal flagellum inflexible and alters the 3D flagellar envelope, thus preventing sperm from reorienting against fluid flow in vitro and efficiently migrating in vivo. Ejaculated CatSperz-null sperm cells retrieved from the mated female uterus partially rescue in vitro fertilization (IVF) that failed with epididymal spermatozoa alone. Human CatSperε is quadrilaterally arranged along the flagella, similar to the CatSper complex in mouse sperm. We speculate that the newly identified CatSperζ subunit is a late evolutionary adaptation to maximize fertilization inside the mammalian female reproductive tract. DOI: http://dx.doi.org/10.7554/eLife.23082.00
Analyzing power in elastic scattering of 6He from polarized proton target at 71 MeV/nucleon
The vector analyzing power has been measured for the elastic scattering of
neutron-rich 6He from polarized protons at 71 MeV/nucleon making use of a newly
constructed solid polarized proton target operated in a low magnetic field and
at high temperature. Two approaches based on local one-body potentials were
applied to investigate the spin-orbit interaction between a proton and a 6He
nucleus. An optical model analysis revealed that the spin-orbit potential for
6He is characterized by a shallow and long-ranged shape compared with the
global systematics of stable nuclei. A semimicroscopic analysis with a
alpha+n+n cluster folding model suggests that the interaction between a proton
and the alpha core is essentially important in describing the p+6He elastic
scattering. The data are also compared with fully microscopic analyses using
non-local optical potentials based on nucleon-nucleon g-matrices.Comment: 20 pages, 20 figures, accepted by Physical Review
Revisiting the optical properties of the FMO protein
We review the optical properties of the FMO complex as found by spectroscopic studies of the Qy band over the last two decades. This article emphasizes the different methods used, both experimental and theoretical, to elucidate the excitonic structure and dynamics of this pigment–protein complex
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