100 research outputs found
Relation between the density-matrix theory and the pairing theory
The time-dependent density-matrix theory (TDDM) gives a correlated ground
state as a stationary solution of the time-dependent equations for one-body and
two-body density matrices. The small amplitude limit of TDDM (STDDM) is a
version of extended RPA theories which include the effects of ground state
correlations. It is shown that the solutions of the Hartree-Fock Bogoliubov
theory and the quasi-particle RPA satisfy the TDDM and STDDM equations,
respectively, when only pairing-type correlations are taken into account in
TDDM and STDDM.Comment: 11 page
Nuclear prolate-shape dominance with the Woods-Saxon potential
We study the prolate-shape predominance of the nuclear ground-state
deformation by calculating the masses of more than two thousand even-even
nuclei using the Strutinsky method, modified by Kruppa, and improved by us. The
influences of the surface thickness of the single-particle potentials, the
strength of the spin-orbit potential, and the pairing correlations are
investigated by varying the parameters of the Woods-Saxon potential and the
pairing interaction. The strong interference between the effects of the surface
thickness and the spin-orbit potential is confirmed to persist for six sets of
the Woods-Saxon potential parameters. The observed behavior of the ratios of
prolate, oblate, and spherical nuclei versus potential parameters are rather
different in different mass regions. It is also found that the ratio of
spherical nuclei increases for weakly bound unstable nuclei. Differences of the
results from the calculations with the Nilsson potential are described in
detail.Comment: 16 pages, 17 figure
Reexpansion Pulmonary Edema after Drainage of a Spontaneous Pneumothorax
Abstract: We report a case of life-threatening reexpansion pulmonary edema following chest tube drainage of spontaneous pneumothorax. Reviewing the literature, pathophysiology, symptoms and therapy of this complication were discussed. Physicians must be aware of the occurrence of reexpansion pulmonary edema following reinflation of the collapsed lung
Pairing correlation in nuclear matter from Skyrme force
The properties of pairing correlation in nuclear matter are investigated by
using various versions of Skyrme forces. Truncation of states involving pairing
correlation, necessary due to zero range nature of the Skyrme force, is
discussed in detail. A plateau appears in pairing gap versus cutoff for each
force. We propose to choose the cutoff parameter in the middle of the plateau
so that the parameterization is independent of nuclides.Comment: Latex, Submitted to Phys. Lett. B, 8 pages, 1 table and 3 uuencoded
postscript figures (modified) included, UT-Komaba 94-
Improved microscopic-macroscopic approach incorporating the effects of continuum states
The Woods-Saxon-Strutinsky method (the microscopic-macroscopic method)
combined with Kruppa's prescription for positive energy levels, which is
necessary to treat neutron rich nuclei, is studied to clarify the reason for
its success and to propose improvements for its shortcomings. The reason why
the plateau condition is met for the Nilsson model but not for the Woods-Saxon
model is understood in a new interpretation of the Strutinsky smoothing
procedure as a low-pass filter. Essential features of Kruppa's level density is
extracted in terms of the Thomas-Fermi approximation modified to describe
spectra obtained from diagonalization in truncated oscillator bases. A method
is proposed which weakens the dependence on the smoothing width by applying the
Strutinsky smoothing only to the deviations from a reference level density. The
BCS equations are modified for the Kruppa's spectrum, which is necessary to
treat the pairing correlation properly in the presence of continuum. The
potential depth is adjusted for the consistency between the microscopic and
macroscopic Fermi energies. It is shown, with these improvements, that the
microscopic-macroscopic method is now capable to reliably calculate binding
energies of nuclei far from stability.Comment: 66 pages, 29 figures, 1 tabl
Study of Superdeformation in Non-rotating States using the Skyrme-Hartree-Fock Method
The superdeformation (SD) in non-rotating states is studied with the HF+BCS
method using the Skyrme interaction. In applying the BCS theory, the seniority
pairing force is employed, of which strengths are determined in order to
reproduce the empirical pairing gap formula, MeV,
through a smooth level density obtained in the Thomas-Fermi approximation.
Properties of superdeformation are investigated by calculating potential energy
surfaces (PES) for various sets of the pairing force strengths and the Skyrme
force parameter for 194Hg and 236,238U. The best results are obtained using
both the SkM* force and the pairing force strength determined in this paper. By
making use of this set of forces, a systematic calculation of SD states is
carried out extensively for even-even nuclei for 20 <= Z <= 82. From our
calculation, the barriers preventing the decay into the normally deformed
states are about twice as high as those predicted by Krieger et al., who used
the same Skyrme interaction but a pairing force stronger than ours. The
differences of the present results from the Nilsson-Strutinsky calculation are
analyzed.Comment: 19 pages in LaTex, 11 Postscript figure
Extensive Hartree-Fock + BCS calculation with Skyrme SIII force
We have performed deformed Hartree-Fock+BCS calculations with the Skyrme SIII
force for the ground states of even-even nuclei with 2 <= Z <= 114 and N
ranging from outside the proton drip line to beyond the experimental frontier
in the neutron-rich side. We obtained spatially localized solutions for 1029
nuclei, together with the second minima for 758 nuclei. The single-particle
wavefunctions are expressed in a three-dimensional Cartesian-mesh
representation, which is suitable to describe nucleon skins, halos, and exotic
shapes as well as properties of ordinary stable nuclei. After explaining some
of the practical procedures of the calculations, we compare the resulting
nuclear masses with experimental data and the predictions of other models. We
also discuss the quadrupole (m=0, 2) and hexadecapole (m=0, 2, 4) deformations,
the skin thicknesses, the halo radii, and the energy difference between the
oblate and the prolate solutions. Our results can be obtained via computer
network.Comment: 20 pages in Latex, 11 Postscript figures, uuencode-gzip-tar file, to
appear in Nuclear Physics A. Data tables available at
ftp://nt1.c.u-tokyo.ac.jp/hfs3
Her yol Roma'ya varmaz!
Taha Toros ArĆivi, Dosya Adı: Taha TorosÄ°stanbul Kalkınma Ajansı (TR10/14/YEN/0033) Ä°stanbul Development Agency (TR10/14/YEN/0033
Serum phosphate levels modify the impact of parathyroid hormone levels on renal outcomes in kidney transplant recipients
Separate assessment of mineral bone disorder (MBD) parameters including calcium, phosphate, parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D (1,25D) predict renal outcomes in kidney transplant recipients (KTRs), with conflicting results. To date, data simultaneously evaluating these parameters and interwoven relations on renal outcomes are scarce. We conducted a prospective long-term follow-up cohort study included 263 KTRs with grafts functioning at least 1Â year after transplantation. The outcome was a composite of estimated GFR halving and graft loss. Cox regression analyses were employed to evaluate associations between a panel of six MBD parameters and renal outcomes. The outcome occurred in 98 KTRs during a median follow-up of 10.7Â years. In a multivariate Cox analysis, intact PTH (iPTH), phosphate, and 1,25D levels were associated with the outcome (hazard ratio, 1.60 per log scale; 95% confidence interval, 1.19â2.14, 1.60 per mg/dL; 1.14â2.23 and 0.82 per 10Â pg/mL; 0.68â0.99, respectively). Competing risk analysis with death as a competing event yielded a similar result. After stratification into four groups by iPTH and phosphate medians, high risks associated with high iPTH was not observed in KTRs with low phosphate levels (P-interaction < 0.1). Only KTRs not receiving active vitamin D, poor 1,25D status predicted the worse outcome (P-interaction < 0.1). High iPTH, phosphate, and low 1,25D, but not FGF23, levels predicted poor renal outcomes. Simultaneous evaluation of PTH and phosphate levels may provide additional information regarding renal allograft prognosis.Doi Y., Hamano T., Ichimaru N., et al. Serum phosphate levels modify the impact of parathyroid hormone levels on renal outcomes in kidney transplant recipients. Scientific Reports 10, 13766 (2020); https://doi.org/10.1038/s41598-020-70709-4
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