6,433 research outputs found
Possibility of synthesizing doubly closed superheavy nucleus
The possibility of synthesizing a doubly magic superheavy nucleus,
, is investigated on the basis of fluctuation-dissipation
dynamics. In order to synthesize this nucleus, we must generate more
neutron-rich compound nuclei because of the neutron emissions from excited
compound nuclei. The compound nucleus has two advantages to
achieving a high survival probability. First, because of small neutron
separation energy and rapid cooling, the shell correction energy recovers
quickly. Secondly, owing to neutron emissions, the neutron number of the
nucleus approaches that of the double closed shell and the nucleus obtains a
large fission barrier. Because of these two effects, the survival probability
of does not decrease until the excitation energy MeV.
These properties lead to a rather high evaporation reside cross section.Comment: 5 pages, 6 figure
The ALTO project at IPN Orsay
In order to probe neutron rich radioactive noble gases produced by
photo-fission, a PARRNe1 experiment (Production d'Atomes Radioactifs Riches en
Neutrons) has been carried out at CERN. The incident electron beam of 50 MeV
was delivered by the LIL machine: LEP Injector Linac. The experiment allowed to
compare under the same conditions two production methods of radioactive noble
gases: fission induced by fast neutrons and photo-fission. The obtained results
show that the use of the electrons is a promising mode to get intense neutron
rich ion beams. Thereafter, the success of this photo-fission experiment, a
conceptual design for the installation at IPN Orsay of a 50 MeV electron
accelerator close to the PARRNe-2 device has been worked out: ALTO Project.
This work has started within a collaboration between IPNO, LAL and CERN groups.Comment: 14 pages, pdf file, International School-Seminar on Heavy-Ion Physics
7 (2002
Quantum tunneling in ^{277}112 and its alpha-decay chain
The -decay half lives of nuclei in the decay from element
are calculated in a WKB framework using DDM3Y interaction and experimental
Q-values. Theoretical estimation of half lives in the same quantum tunneling
model, using Q-values from the mass formula of
Muntian-Hofmann-Patyk-Sobiczewski, are also presented. Calculated results
furnish corroborating evidence for the experimental findings at RIKEN and GSI.
Certain discrepancies indicate necessity of a better mass formula. Further
experimental data with higher statistics would also be useful.Comment: 10 page
Magic nuclei in superheavy valley
An extensive theoretical search for the proton magic number in the superheavy
valley beyond 82 and corresponding neutron magic number after 126 is
carried out. For this we scanned a wide range of elements and their
isotopes. The well established non-relativistic Skryme-Hartree-Fock and
Relativistic Mean Field formalisms with various force parameters are used.
Based on the calculated systematics of pairing gap, two neutron separation
energy and the shell correction energy for these nuclei, we find 120 as the
next proton magic and N=172, 182/184, 208 and 258 the subsequent neutron magic
numbers.Comment: 5 Pages 3 Figures 2 Tables; Phys. Lett. B (2011) (Communicated
植民地時代の台湾における日常生活と日記
Diaries offer insights into everyday modernity. The appeal of diaries is to be explained by a growing academic interest in everyday life. Our world is part of-- not external to--everyday life. Everyday life, as we know it, is of course never perfect, but to treat it with silence, as has been the practice, is to deny both its problematic as a discourse and its potentiality for generating a counter-discourse.In section I of what follows, I take up the issue of "diaries as everyday life" to illustrate everyday practice in colonial Taiwan. In Section II, using Utsumi Chuji as a case study, I demonstrate that the Utsumi diary reveals much of the man\u27s private life, family, and leisure activities, and also of his social networking in a colonial context. In Section III, I draw on the newly published diaries by two elite Taiwanese, Zhang Lijun and Lin Xiantang, and explore them in their own right in the colonial setting of Taiwan under Japanese rule (1895-1945). These diaries also reveal the limitations of the Utsumi diary. The information provided in diaries is a vital vew source for reconstructing the history of colonial Taiwan. Thistrend of discovering dairies as Taiwan studies reflects both the optimism and the anxieties of the post-martial-law generations as they seek self-identity, just as the construction of a "national" identity in Taiwan seems to be all but impossible
PI3K/mTORC2 regulates TGF-β/Activin signalling by modulating Smad2/3 activity via linker phosphorylation
Crosstalk between the phosphatidylinositol 3-kinase (PI3K) and the transforming growth factor-β signalling pathways play an important role in regulating many cellular functions. However, the molecular mechanisms underpinning this crosstalk remain unclear. Here, we report that PI3K signalling antagonizes the Activin-induced definitive endoderm (DE) differentiation of human embryonic stem cells by attenuating the duration of Smad2/3 activation via the mechanistic target of rapamycin complex 2 (mTORC2). Activation of mTORC2 regulates the phosphorylation of the Smad2/3-T220/T179 linker residue independent of Akt, CDK and Erk activity. This phosphorylation primes receptor-activated Smad2/3 for recruitment of the E3 ubiquitin ligase Nedd4L, which in turn leads to their degradation. Inhibition of PI3K/mTORC2 reduces this phosphorylation and increases the duration of Smad2/3 activity, promoting a more robust mesendoderm and endoderm differentiation. These findings present a new and direct crosstalk mechanism between these two pathways in which mTORC2 functions as a novel and critical mediator
Skyrme Hartree-Fock Calculations for the Alpha Decay Q Values of Super-Heavy Nuclei
Hartree-Fock calculations with the SKX Skyrme interaction are carried out to
obtain alpha-decay Q values for deformed nuclei above Pb assuming axial
symmetry. The results for even-even nuclei are compared with experiment and
with previous calculations. Predictions are made for alpha-decay Q values and
half-lives of even-even super-heavy nuclei. The results are also compared for
the recently discovered odd-even chain starting at Z=112 and N=165.Comment: 17 pages, 8 figures, 1 tabl
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