6,252 research outputs found
Non-equilibrium thermodynamics. IV: Generalization of Maxwell, Claussius-Clapeyron and Response Functions Relations, and the Prigogine-Defay Ratio for Systems in Internal Equilibrium
We follow the consequences of internal equilibrium in non-equilibrium systems
that has been introduced recently [Phys. Rev. E 81, 051130 (2010)] to obtain
the generalization of Maxwell's relation and the Clausius-Clapeyron relation
that are normally given for equilibrium systems. The use of Jacobians allow for
a more compact way to address the generalized Maxwell relations; the latter are
available for any number of internal variables. The Clausius-Clapeyron relation
in the subspace of observables show not only the non-equilibrium modification
but also the modification due to internal variables that play a dominant role
in glasses. Real systems do not directly turn into glasses (GL) that are frozen
structures from the supercooled liquid state L; there is an intermediate state
(gL) where the internal variables are not frozen. Thus, there is no single
glass transition. A system possess several kinds of glass transitions, some
conventional (L \rightarrow gL; gL\rightarrow GL) in which the state change
continuously and the transition mimics a continuous or second order transition,
and some apparent (L\rightarrow gL; L\rightarrow GL) in which the free energies
are discontinuous so that the transition appears as a zeroth order transition,
as discussed in the text. We evaluate the Prigogine-Defay ratio {\Pi} in the
subspace of the observables at these transitions. We find that it is normally
different from 1, except at the conventional transition L\rightarrow gL, where
{\Pi}=1 regardless of the number of internal variables.Comment: 42 pages, 3 figures, citations correcte
The Transcriptional Landscape of Marek’s Disease Virus in Primary Chicken B Cells Reveals Novel Splice Variants and Genes
Marek’s disease virus (MDV) is an oncogenic alphaherpesvirus that infects chickens and poses a serious threat to poultry health. In infected animals, MDV efficiently replicates in B cells in various lymphoid organs. Despite many years of research, the viral transcriptome in primary target cells of MDV remained unknown. In this study, we uncovered the transcriptional landscape of the very virulent RB1B strain and the attenuated CVI988/Rispens vaccine strain in primary chicken B cells using high-throughput RNA-sequencing. Our data confirmed the expression of known genes, but also identified a novel spliced MDV gene in the unique short region of the genome. Furthermore, de novo transcriptome assembly revealed extensive splicing of viral genes resulting in coding and non-coding RNA transcripts. A novel splicing isoform of MDV UL15 could also be confirmed by mass spectrometry and RT-PCR. In addition, we could demonstrate that the associated transcriptional motifs are highly conserved and closely resembled those of the host transcriptional machinery. Taken together, our data allow a comprehensive re-annotation of the MDV genome with novel genes and splice variants that could be targeted in further research on MDV replication and tumorigenesis
Phase resolved spectroscopy of the Vela pulsar with XMM-Newton
The ~10^4 y old Vela Pulsar represents the bridge between the young Crab-like
and the middle-aged rotation powered pulsars. Its multiwavelength behaviour is
due to the superposition of different spectral components. We take advantage of
the unprecedented harvest of photons collected by XMM-Newton to assess the Vela
Pulsar spectral shape and to study the pulsar spectrum as a function of its
rotational phase. As for the middle-aged pulsars Geminga, PSR B0656+14 and PSR
B1055-52 (the "Three Musketeers"), the phase-integrated spectrum of Vela is
well described by a three-component model, consisting of two blackbodies
(T_bb1=(1.06+/-0.03)x10^6 K, R_bb1=5.1+/-0.3 km, T_bb2=(2.16+/-0.06)x10^6 K,
R_bb2=0.73+/-0.08 km) plus a power-law (gamma=2.2+/-0.3). The relative
contributions of the three components are seen to vary as a function of the
pulsar rotational phase. The two blackbodies have a shallow 7-9% modulation.
The cooler blackbody, possibly related to the bulk of the neutron star surface,
has a complex modulation, with two peaks per period, separated by ~0.35 in
phase, the radio pulse occurring exactly in between. The hotter blackbody,
possibly originating from a hot polar region, has a nearly sinusoidal
modulation, with a single, broad maximum aligned with the second peak of the
cooler blackbody, trailing the radio pulse by ~0.15 in phase. The non thermal
component, magnetospheric in origin, is present only during 20% of the pulsar
phase and appears to be opposite to the radio pulse. XMM-Newton phase-resolved
spectroscopy unveils the link between the thermally emitting surface of the
neutron star and its charge-filled magnetosphere, probing emission geometry as
a function of the pulsar rotation. This is a fundamental piece of information
for future 3-dimensional modeling of the pulsar magnetosphere.Comment: 27 pages, 9 figures. Accepted for publication in Ap
Ergodicity breaking in a model showing many-body localization
We study the breaking of ergodicity measured in terms of return probability
in the evolution of a quantum state of a spin chain. In the non ergodic phase a
quantum state evolves in a much smaller fraction of the Hilbert space than
would be allowed by the conservation of extensive observables. By the anomalous
scaling of the participation ratios with system size we are led to consider the
distribution of the wave function coefficients, a standard observable in modern
studies of Anderson localization. We finally present a criterion for the
identification of the ergodicity breaking (many-body localization) transition
based on these distributions which is quite robust and well suited for
numerical investigations of a broad class of problems.Comment: 5 pages, 5 figures, final versio
Toward validation of simulated accelerograms via prediction equations for nonlinear SDOF response
Seismic
structural
risk
analysis
of
critical
facilities
may
require
nonlinear
dynamic
analysis
for
which
record
selection
is
one
of
the
key
issues.
Notwithstanding
the
increasing availability of database of strong-motion records, it may be hard to find
accelerograms that fit a specific scenario (e.g., in terms of magnitude and distance)
resulting from hazard assessment at the site of interest. A possible, alternative, approach
can be the use of artificial and/or simulated ground motion in lieu of real records. Their
employment requires systematic engineering validation in terms of structural response
and/or seismic risk. Prediction equations for peak and cyclic inelastic single degree of
freedom systems’ response, based on Italian accelerometric data, are discussed in this
study as a possible benchmark, alongside real record counterparts, for the validation of
synthetic records. Even if multiple events would be in principle required, an extremely
preliminary validation is carried out considering only four simulated records of the 1980
Irpinia (southern Italy)
M
w
6.9 earthquake. Simulated records are obtained through a
broadband hybrid integral-composite technique. Results show how this simulation
method may lead to generally acceptable results. It is also emphasized how this kind
of validation may provide additional results with respect to classical signal-to-signal
comparison of real and simulated records
The 2003 eclipse of EE Cep is coming. A review of past eclipses
EE Cep is an eclipsing binary with a period of 5.6 years. The next eclipse
will occur soon, in May-June 2003, and all available past eclipses were
collected and briefly analysed. EE Cep shows very large changes of the shape
and the depth of minima during different eclipses, however it is possible to
single out some persistent features. The analysis suggests that the eclipsing
body should be a long object surrounded by an extended semi-transparent
envelope. As an explanation, a model of a precessing optically thick disc,
inclined to the plane of the binary orbit, is invoked. The changes of its
spatial orientation, which is defined by the inclination of the disc and the
tilt, induced most probably by precession of the disc spin axis with a period
of about 50 years, produce strange photometric behaviour of this star. The
H_alpha emission, and possibly the NaI absorptions, show significant changes
during several months outside of the eclipse phase.Comment: 7 pages, 7 figures, LaTeX2e, accepted by A&
Nb-doped TiO2 thin films deposited by spray pyrolysis method
Undoped TiO2 and Nb-doped TiO2 thin films have been deposited by spray pyrolysis method on ITO/glass substrates. All the as-deposited films are amorphous, as shown by X-Ray Diffraction. Under certain conditions of heat-treatment in air, the films deposited by pyrolysis became pure anatase. The hydrophilic properties of all the films were investigated, and a comparison was made as a function of the heat treatment, and as a function of Nb doping. Contact angles lower then 3 deg. have been obtained, after irradiation times specific for each film
Perfectly Translating Lattices on a Cylinder
We perform molecular dynamics simulations on an interacting electron gas
confined to a cylindrical surface and subject to a radial magnetic field and
the field of the positive background. In order to study the system at lowest
energy states that still carry a current, initial configurations are obtained
by a special quenching procedure. We observe the formation of a steady state in
which the entire electron-lattice cycles with a common uniform velocity.
Certain runs show an intermediate instability leading to lattice
rearrangements. A Hall resistance can be defined and depends linearly on the
magnetic field with an anomalous coefficient reflecting the manybody
contributions peculiar to two dimensions.Comment: 13 pages, 5 figure
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