12,018 research outputs found
Electric dipole response of 208Pb from proton inelastic scattering: constraints on neutron skin thickness and symmetry energy
The electric dipole (E1) response of 208Pb has been precisely determined by
measuring Coulomb excitation induced by proton scattering at very forward
angles. The electric dipole polarizability, defined as inverse energy-weighted
sum rule of the E1 strength, has been extracted as 20.1+-0.6 fm^3. The data can
be used to constrain the neutron skin thickness of 208Pb to
0.168(+-0.009)_expt(+-0.013)_theo(+-0.021)_est fm, where the subscript "expt"
refers to the experimental uncertainty, "theor" to the theoretical confidence
band and "est" to the uncertainty associated with the estimation of the
symmetry energy at the saturation density. In addition, a constraint band has
been extracted in the plane of the symmetry energy (J) and its slope parameter
(L) at the saturation density.Comment: 6 pages, 8 figures, revised manuscript submitted to special volume of
Eur. Phys. J. A on symmetry energ
Translation termination depends on the sequential ribosomal entry of eRF1 and eRF3.
Translation termination requires eRF1 and eRF3 for polypeptide-and tRNA-release on stop codons. Additionally, Dbp5/DDX19 and Rli1/ABCE1 are required; however, their function in this process is currently unknown. Using a combination of in vivo and in vitro experiments, we show that they regulate a stepwise assembly of the termination complex. Rli1 and eRF3-GDP associate with the ribosome first. Subsequently, Dbp5-ATP delivers eRF1 to the stop codon and in this way prevents a premature access of eRF3. Dbp5 dissociates upon placing eRF1 through ATP-hydrolysis. This in turn enables eRF1 to contact eRF3, as the binding of Dbp5 and eRF3 to eRF1 is mutually exclusive. Defects in the Dbp5-guided eRF1 delivery lead to premature contact and premature dissociation of eRF1 and eRF3 from the ribosome and to subsequent stop codon readthrough. Thus, the stepwise Dbp5-controlled termination complex assembly is essential for regular translation termination events. Our data furthermore suggest a possible role of Dbp5/DDX19 in alternative translation termination events, such as during stress response or in developmental processes, which classifies the helicase as a potential drug target for nonsense suppression therapy to treat cancer and neurodegenerative diseases
Evolutional Entanglement in Nonequilibrium Processes
Entanglement in nonequilibrium systems is considered. A general definition
for entanglement measure is introduced, which can be applied for characterizing
the level of entanglement produced by arbitrary operators. Applying this
definition to reduced density matrices makes it possible to measure the
entanglement in nonequilibrium as well as in equilibrium statistical systems.
An example of a multimode Bose-Einstein condensate is discussed.Comment: 10 pages, Late
All-order evaluation of weak measurements: --- The cases of an operator which satisfies the property ---
Some exact formulae of the expectation values and probability densities in a
weak measurement for an operator which satisfies the property are derived. These formulae include all-order effects of the unitary
evolution due to the von-Neumann interaction. These are valid not only in the
weak measurement regime but also in the strong measurement regime and tell us
the connection between these two regime. Using these formulae, arguments of the
optimization of the signal amplification and the signal to noise ratio are
developed in two typical experimental setups.Comment: 17 pages, 10 figures (v1); Fig.3 and some typos are corrected (v2);
Comments and references are added and some typos are corrected (v3
Enhanced spin accumulation at room temperature in graphene spin valves with amorphous carbon interfacial layers
We demonstrate a large enhancement of the spin accumulation in monolayer
graphene following electron-beam induced deposition of an amorphous carbon
layer at the ferromagnet-graphene interface. The enhancement is 10^4-fold when
graphene is deposited onto poly(methyl metacrylate) (PMMA) and exposed with
sufficient electron-beam dose to cross-link the PMMA, and 10^3-fold when
graphene is deposited directly onto SiO2 and exposed with identical dose. We
attribute the difference to a more efficient carbon deposition in the former
case due to an increase in the presence of compounds containing carbon, which
are released by the PMMA. The amorphous carbon interface can sustain very large
current densities without degrading, which leads to very large spin
accumulations exceeding 500 microeVs at room temperature
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