948 research outputs found
A model-theoretic interpretation of environmentally-induced superselection
Environmentally-induced superselection or "einselection" has been proposed as
an observer-independent mechanism by which apparently classical systems
"emerge" from physical interactions between degrees of freedom described
completely quantum-mechanically. It is shown that einselection can only
generate classical systems if the "environment" is assumed \textit{a priori} to
be classical; einselection therefore does not provide an observer-independent
mechanism by which classicality can emerge from quantum dynamics. Einselection
is then reformulated in terms of positive operator-valued measures (POVMs)
acting on a global quantum state. It is shown that this re-formulation enables
a natural interpretation of apparently-classical systems as virtual machines
that requires no assumptions beyond those of classical computer science.Comment: 15 pages, 1 figure; minor correction
On the Particle Data Group evaluation of Psi' and chi_c Branching Ratios
I propose a new evaluation of and branching ratios
which avoids the correlations affecting the current Particle Data Group
evaluation.
These correlations explain the apparent technique-dependent discrepancies
between the available determinations of the
and under the hypotesis that the current
values of the branching ratios are
overestimated.
In the process I also noticed that Particle Data Group has not restated many
of the older measurements, when necessary, for the new value of , which significantly affects the evaluation of some
relevant and exclusive branching ratios.Comment: 13 pages. Revised version. Submitted to Phys. Rev.
Discrete Particle Swarm Optimization for the minimum labelling Steiner tree problem
Particle Swarm Optimization is an evolutionary method inspired by the
social behaviour of individuals inside swarms in nature. Solutions of the problem are
modelled as members of the swarm which fly in the solution space. The evolution is
obtained from the continuous movement of the particles that constitute the swarm
submitted to the effect of the inertia and the attraction of the members who lead the
swarm. This work focuses on a recent Discrete Particle Swarm Optimization for combinatorial optimization, called Jumping Particle Swarm Optimization. Its effectiveness is
illustrated on the minimum labelling Steiner tree problem: given an undirected labelled
connected graph, the aim is to find a spanning tree covering a given subset of nodes,
whose edges have the smallest number of distinct labels
Electromagnetic form factors in the J/\psi mass region: The case in favor of additional resonances
Using the results of our recent analysis of e^+e^- annihilation, we plot the
curves for the diagonal and transition form factors of light hadrons in the
time-like region up to the production threshold of an open charm quantum
number. The comparison with existing data on the decays of J/\psi into such
hadrons shows that some new resonance structures may be present in the mass
range between 2 GeVand the J/\psi mass. Searching them may help in a better
understanding of the mass spectrum in both the simple and a more sophisticated
quark models, and in revealing the details of the three-gluon mechanism of the
OZI rule breaking in K\bar K channel.Comment: Formulas are added, typo is corrected, the text is rearranged.
Replaced to match the version accepted in Phys Rev
Antiviral responses are shaped by heterogeneity in viral replication dynamics
Antiviral signalling, which can be activated in host cells upon virus infection, restricts virus replication and communicates infection status to neighbouring cells. The antiviral response is heterogeneous, both quantitatively (efficiency of response activation) and qualitatively (transcribed antiviral gene set). To investigate the basis of this heterogeneity, we combined Virus Infection Real-time IMaging (VIRIM), a live-cell single-molecule imaging method, with real-time readouts of the dsRNA sensing pathway to analyse the response of human cells to encephalomyocarditis virus (EMCV) infection. We find that cell-to-cell heterogeneity in viral replication rates early in infection affect the efficiency of antiviral response activation, with lower replication rates leading to more antiviral response activation. Furthermore, we show that qualitatively distinct antiviral responses can be linked to the strength of the antiviral signalling pathway. Our analyses identify variation in early viral replication rates as an important parameter contributing to heterogeneity in antiviral response activation
Computerized cognitive training in prostate cancer patients on androgen deprivation therapy: a pilot study
© 2017, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: Prostate cancer patients who have undergone androgen deprivation therapy (ADT) may experience cognitive impairment, yet there is an unmet need for nonpharmacological interventions to address cognitive impairment in this population. This study examines the feasibility, acceptability, and preliminary efficacy of a home-based computerized cognitive training (CCT) program to treat cancer-related cognitive impairment. Methods: Sixty men who had received ≥ 3 months of ADT were screened for at least mild cognitive or neurobehavioral impairment and randomized to 8 weeks of CCT or usual care. Follow-up assessments occurred immediately post-intervention or equivalent (T2) and 8 weeks later (T3). The acceptability of CCT was also assessed. Results: Feasibility:A priori feasibility thresholds were partially met (i.e., randomization rate \u3e 50%, retention rate \u3e 70% excluding CCT drop-outs, but \u3c 70% for intent-to-treat). Acceptability: Participants were mostly satisfied with CCT and found it somewhat enjoyable, though barriers to uptake existed. Preliminary efficacy: Linear mixed models indicated significant time by group effects favorable to CCT in reaction time (p =.01), but unfavorable to CCT in verbal and visual memory (ps \u3c .05). Memory was temporarily suppressed in the CCT group at T2, but normalized by T3. There was no effect of CCT on self-reported cognitive functioning, neurobehavioral functioning, nor quality of life. Conclusions: This study provides tentative support for the feasibility and acceptability of CCT to treat mild cognitive impairment in ADT patients. CCT had a beneficial effect on reaction time, but temporarily suppressed memory. CCT’s benefits may be limited to a narrow area of functioning. Larger-scale studies are needed
Enhancing Transport Efficiency by Hybrid Routing Strategy
Traffic is essential for many dynamic processes on real networks, such as
internet and urban traffic systems. The transport efficiency of the traffic
system can be improved by taking full advantage of the resources in the system.
In this paper, we propose a dual-strategy routing model for network traffic
system, to realize the plenary utility of the whole network. The packets are
delivered according to different "efficient routing strategies" [Yan, et al,
Phys. Rev. E 73, 046108 (2006)]. We introduce the accumulate rate of packets,
{\eta} to measure the performance of traffic system in the congested phase, and
propose the so-called equivalent generation rate of packet to analyze the
jamming processes. From analytical and numerical results, we find that, for
suitable selection of strategies, the dual- strategy system performs better
than the single-strategy system in a broad region of strategy mixing ratio. The
analytical solution to the jamming processes is verified by estimating the
number of jammed nodes, which coincides well with the result from simulation.Comment: 6 pages, 3 figure
Hot and repulsive traffic flow
We study a message passing model, applicable also to traffic problems. The
model is implemented in a discrete lattice, where particles move towards their
destination, with fluctuations around the minimal distance path. A repulsive
interaction between particles is introduced in order to avoid the appearance of
traffic jam. We have studied the parameter space finding regions of fluid
traffic, and saturated ones, being separated by abrupt changes. The improvement
of the system performance is also explored, by the introduction of a
non-constant potential acting on the particles. Finally, we deal with the
behavior of the system when temporary failures in the transmission occurs.Comment: 22 pages, uuencoded gzipped postscript file. 11 figures include
Right Handed Weak Currents in Sum Rules for Axialvector Constant Renormalization
The recent experimental results on deep inelastic polarized lepton scattering
off proton, deuteron and He together with polari% zed neutron
-decay data are analyzed. It is shown that the problem of Ellis-Jaffe
and Bjorken sum rules deficiency and the neutron paradox could be solved
simultaneously by assuming the small right handed current (RHC) admixture in
the weak interaction Lagrangian. The possible RHC impact on pion-nucleon
-term and Gamow-Teller sum rule for nuclear reactions is
pointed out.Comment: to be published in Phys. Rev. Lett. LaTeX, 8 pages, 21 k
Spacings of Quarkonium Levels with the Same Principal Quantum Number
The spacings between bound-state levels of the Schr\"odinger equation with
the same principal quantum number but orbital angular momenta
differing by unity are found to be nearly equal for a wide range of power
potentials , with . Semiclassical approximations are in accord with this behavior. The
result is applied to estimates of masses for quarkonium levels which have not
yet been observed, including the 2P states and the 1D
states.Comment: 20 pages, latex, 3 uuencoded figures submitted separately (process
using psfig.sty
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