731 research outputs found
On the IMF Multiplicity in Au+Au Reactions
Intermediate mass fragment (IMF) multiplicity has been investigated for Au+Au
reactions at incident energies of 100, 250 and 400 MeV/A. From the analysis of
the impact-parameter-dependence of the IMF multiplicity using our QMD plus
statistical evaporation model, we found that 1) statistical decay process
modifies the results greatly, and 2) the Fermi motion plays a role to increase
the IMF multiplicity for whole impact-parameter range.Comment: 9pages, Latex is used, 2 Postscript figures are available by request
from [email protected]
Relativistic Effects in the Transverse Flow in the Molecular Dynamics Framework
In order to investigate relativistic effects we compare the transverse flow
calculated by using the four versions of the QMD approaches with that of the
full covariant RQMD approach. From the comparison we conclude that the
simplified RQMD (RQMD/S), which uses the common time coordinate to all
particles, can be used instead of RQMD up to 6 GeV/u.Comment: 6pages, Latex is used, 1 Postscript figures are available by request
from [email protected]
Linpack evaluation on a supercomputer with heterogeneous accelerators
Abstract—We report Linpack benchmark results on the TSUBAME supercomputer, a large scale heterogeneous system equipped with NVIDIA Tesla GPUs and ClearSpeed SIMD accelerators. With all of 10,480 Opteron cores, 640 Xeon cores, 648 ClearSpeed accelerators and 624 NVIDIA Tesla GPUs, we have achieved 87.01TFlops, which is the third record as a heterogeneous system in the world. This paper describes careful tuning and load balancing method required to achieve this performance. On the other hand, since the peak speed is 163 TFlops, the efficiency is 53%, which is lower than other systems. This paper also analyses this gap from the aspect of system architecture. I
A Poincar\'e covariant cascade method for high-energy nuclear collisions
We present a Poincar\'e covariant cascade algorithm based on the constrained
Hamiltonian dynamics in an -dimensional phase space to simulate the
Boltzmann-type two-body collision term. We compare this covariant cascade
algorithm with traditional -dimensional phase-space cascade algorithms. To
validate the covariant cascade algorithm, we perform box calculations. We
examine the frame dependence of the algorithm in a one-dimensionally expanding
system as well as the compression stages of colliding two nuclei. We confirm
that our covariant cascade method is reliable to simulate high-energy nuclear
collisions. Furthermore, we present Lorentz-covariant equations of motion for
the -body system interacting via potentials, which can be efficiently solved
numerically.Comment: 13 pages, 10 figures, 1 table, typos fixe
Impact of carotid atherosclerosis on long-term mortality in chronic hemodialysis patients
Impact of carotid atherosclerosis on long-term mortality in chronic hemodialysis patients.BackgroundCardiovascular event is the major cause of mortality in patients on maintenance hemodialysis. We prospectively tested the predictive values of atherosclerotic parameters for all-cause and cardiovascular outcomes in 219 hemodialysis patients (age, 58 ± 13 years; time on hemodialysis, 13 ± 7 years; male/female, 144/75).MethodsWe measured blood homocysteine (Hcy), ultrasound carotid artery intima media thickness (IMT) and % aortic wall calcification at L2/3 region [% of calcification index in the abdominal aortic wall (%ACI)] by computed tomography (CT) scan, and followed all patients for 5 years.ResultsDuring the follow-up periods, 54 patients (25%) died, 40 (74%) of them of cardiovascular causes. IMT was significantly higher in patients who expired (0.75 ± 0.02mm) than in those who survived (0.62 ± 0.01mm). IMT was significantly correlated with age (r = 0.47, P < 0.01) and %ACI (r = 0.27, P < 0.01). The survival rate during the observation was significantly lower in the final IMT third (58%) than in the first (90%) and the middle IMT third (80%) (P < 0.01). Multivariate Cox proportional hazards analysis revealed that diabetes and IMT became independent determinants of all-cause and cardiovascular death. Adjusted hazards ratios of all-cause and cardiovascular mortality for an increase of 0.1mm in IMT were 1.31 (95% CI, 1.07 to 1.59) and 1.41 (95% CI, 1.12 to 1.76). In contrast, %ACI at abdominal aorta and blood Hcy did not affect their 5-year mortality.ConclusionThese findings suggested that measurement of carotid artery IMT is useful for predicting long-term mortality in patients receiving maintenance hemodialysis
Nucleon Flow and Fragment Flow in Heavy Ion Reactions
The collective flow of nucleons and that of fragments in the 12C + 12C
reaction below 150 MeV/nucleon are calculated with the antisymmetrized version
of molecular dynamics combined with the statistical decay calculation. Density
dependent Gogny force is used as the effective interaction. The calculated
balance energy is about 100 MeV/nucleon, which is close to the observed value.
Below the balance energy, the absolute value of the fragment flow is larger
than that of nucleon flow, which is also in accordance with data. The
dependence of the flow on the stochastic collision cross section and its origin
are discussed. All the results are naturally understood by introducing the
concept of two components of flow: the flow of dynamically emitted nucleons and
the flow of the nuclear matter which contributes to both the flow of fragments
and the flow of nucleons due to the statistical decay.Comment: 20 pages, PostScript figures, LaTeX with REVTeX and EPSF, KUNS 121
福祉コミュニティ形成に関する一考察 : 板橋区における実践事例を手がかりとして
In the theory of community welfare, formation of Welfare Community is becoming a big subject. But Welfare Community is an expectation concept than a fact concept. This paper is to study about the process of formation of Welfare Community from a case Study of the Itabashi Normalization Network, in Tokyo. What is necessary to the subject of formation of Welfare Community are independent system, sympathy system, propulsion system. There are function that, communication, socio-education, community care service, between each subject. These function as communication, socio-education, community care service and help form a welfare community. As a result communication develops into mutual help, socio-education into community development, and community care service into protection of human rights
Analysis of proton-induced fragment production cross sections by the Quantum Molecular Dynamics plus Statistical Decay Model
The production cross sections of various fragments from proton-induced
reactions on Fe and Al have been analyzed by the Quantum
Molecular Dynamics (QMD) plus Statistical Decay Model (SDM). It was found that
the mass and charge distributions calculated with and without the statistical
decay have very different shapes. These results also depend strongly on the
impact parameter, showing an importance of the dynamical treatment as realized
by the QMD approach. The calculated results were compared with experimental
data in the energy region from 50 MeV to 5 GeV. The QMD+SDM calculation could
reproduce the production cross sections of the light clusters and
intermediate-mass to heavy fragments in a good accuracy. The production cross
section of Be was, however, underpredicted by approximately 2 orders of
magnitude, showing the necessity of another reaction mechanism not taken into
account in the present model.Comment: 12 pages, Latex is used, 6 Postscript figures are available by
request from [email protected]
Quantum Molecular Dynamics Approach to the Nuclear Matter Below the Saturation Density
Quantum molecular dynamics is applied to study the ground state properties of
nuclear matter at subsaturation densities. Clustering effects are observed as
to soften the equation of state at these densities. The structure of nuclear
matter at subsaturation density shows some exotic shapes with variation of the
density.Comment: 21 pages of Latex (revtex), 9 Postscript figure
- …