909 research outputs found
Aging and Holography
Aging phenomena are examples of `non-equilibrium criticality' and can be
exemplified by systems with Galilean and scaling symmetries but no time
translation invariance. We realize aging holographically using a deformation of
a non-relativistic version of gauge/gravity duality. Correlation functions of
scalar operators are computed using holographic real-time techniques, and agree
with field theory expectations. At least in this setup, general aging phenomena
are reproduced holographically by complexifying the bulk space-time geometry,
even in Lorentzian signature.Comment: 1 pdf figur
Study of the filamentary infrared dark cloud G192.76+00.10 in the S254-S258 OB complex
We present results of a high resolution study of the filamentary infrared
dark cloud G192.76+00.10 in the S254-S258 OB complex in several molecular
species tracing different physical conditions. These include three
isotopologues of carbon monoxide (CO), ammonia (NH), carbon monosulfide
(CS). The aim of this work is to study the general structure and kinematics of
the filamentary cloud, its fragmentation and physical parameters. The gas
temperature is derived from the NH and
CO(2--1) lines and the CO(1--0), CO(2--1) emission is used
to investigate the overall gas distribution and kinematics. Several dense
clumps are identified from the CS(2--1) data. Values of the gas temperature lie
in the ranges K, column density reaches the value 5.1
10 cm. The width of the filament is of order 1 pc. The masses of
the dense clumps range from M to M.
They appear to be gravitationally unstable. The molecular emission shows a gas
dynamical coherence along the filament. The velocity pattern may indicate
longitudinal collapse.Comment: 10 pages, 9 figures, accepted for publication in Research in
Astronomy and Astrophysic
The clinical application of a new synthetic bone grafting material in oral and maxillofacial surgery
A novel bone formation material based on hydroxyapatite-xerogel is presented.
With the use of the innovative sol-gel technology this material is produced in the
low-temperature range by the addition of silicon dioxide; in its structure it mimics
to a great extent the natural bone matrix. This results in high osteoconductivity
and an osteoprotective effect as well as in complete biodegradation corresponding
to bone formation in the course of natural bone remodelling. Two case reports
are presented
The lifespan method as a tool to study criticality in absorbing-state phase transitions
In a recent work, a new numerical method (the lifespan method) has been
introduced to study the critical properties of epidemic processes on complex
networks [Phys. Rev. Lett. \textbf{111}, 068701 (2013)]. Here, we present a
detailed analysis of the viability of this method for the study of the critical
properties of generic absorbing-state phase transitions in lattices. Focusing
on the well understood case of the contact process, we develop a finite-size
scaling theory to measure the critical point and its associated critical
exponents. We show the validity of the method by studying numerically the
contact process on a one-dimensional lattice and comparing the findings of the
lifespan method with the standard quasi-stationary method. We find that the
lifespan method gives results that are perfectly compatible with those of
quasi-stationary simulations and with analytical results. Our observations
confirm that the lifespan method is a fully legitimate tool for the study of
the critical properties of absorbing phase transitions in regular lattices
A Search for OH Megamasers at z > 0.1. III. The Complete Survey
We present the final results from the Arecibo Observatory OH megamaser
survey. We discuss in detail the properties of the remaining 18 OH megamasers
detected in the survey, including 3 redetections. We place upper limits on the
OH emission from 85 nondetections and examine the properties of 25 ambiguous
cases for which the presence or absence of OH emission could not be determined.
The complete survey has discovered 50 new OH megamasers (OHMs) in
(ultra)luminous infrared galaxies ([U]LIRGs) which doubles the sample of known
OHMs and increases the sample at z>0.1 sevenfold. The Arecibo OH megamaser
survey indicates that the OHM fraction in LIRGs is an increasing function of
the far-IR luminosity (L_{FIR}) and far-IR color, reaching a fraction of
roughly one third in the warmest ULIRGs. Significant relationships between OHMs
and their hosts are few, primarily due to a mismatch in size scales of measured
properties and an intrinsic scatter in OHM properties roughly equal to the span
of the dataset. We investigate relationships between OHMs and their hosts with
a variety of statistical tools including survival analysis, partial correlation
coefficients, and a principal component analysis. There is no apparent OH
megamaser ``fundamental plane.'' We compile data on all previously known OHMs
and evaluate the possible mechanisms and relationships responsible for OHM
production in merging systems. The OH-FIR relationship is reexamined using the
doubled OHM sample and found to be significantly flatter than previously
thought: L_{OH} ~ L_{FIR}^{1.2 +/- 0.1}. This near-linear dependence suggests a
mixture of saturated and unsaturated masers, either within individual galaxies
or across the sample.Comment: 28 pages, 14 figures, accepted by AJ. (AASTeX, includes emulateapj5
and onecolfloat5
The manufacture of synthetic non-sintered and degradable bone grafting substitutes
A new synthetic bone grafting substitute (NanoBone®, ARTOSS GmbH, Germany)
is presented. This is produced by a new technique, the sol-gel-method. This
bone grafting substitute consists of nanocrystalline hydroxyapatite (HA) and
nanostructured silica (SiO2). By achieving a highly porous structure good osteoconductivity
can be seen. In addition, the material will be completely biodegraded
and new own bone is formed. It has been demonstrated that NanoBone® is
biodegraded by osteoclasts in a manner comparable to the natural bone remodelling
process
Scaling Limit of the Ising Model in a Field
The dilute A_3 model is a solvable IRF (interaction round a face) model with
three local states and adjacency conditions encoded by the Dynkin diagram of
the Lie algebra A_3. It can be regarded as a solvable version of an Ising model
at the critical temperature in a magnetic field. One therefore expects the
scaling limit to be governed by Zamolodchikov's integrable perturbation of the
c=1/2 conformal field theory. Indeed, a recent thermodynamic Bethe Ansatz
approach succeeded to unveil the corresponding E_8 structure under certain
assumptions on the nature of the Bethe Ansatz solutions. In order to check
these conjectures, we perform a detailed numerical investigation of the
solutions of the Bethe Ansatz equations for the critical and off-critical
model. Scaling functions for the ground-state corrections and for the lowest
spectral gaps are obtained, which give very precise numerical results for the
lowest mass ratios in the massive scaling limit. While these agree perfectly
with the E_8 mass ratios, we observe one state which seems to violate the
assumptions underlying the thermodynamic Bethe Ansatz calculation. We also
analyze the critical spectrum of the dilute A_3 model, which exhibits massive
excitations on top of the massless states of the Ising conformal field theory.Comment: 29 pages, RevTeX, 11 PostScript figures included by epsf, using
amssymb.sty (v2.2
Mass resolution optimization in a large isotopic composition experiment
A range-energy experiment was built to measure the isotopic composition of galactic cosmic rays. An enrichment of neutron rich isotopes, 22Ne and (25Mg + 26Mg) in particular, when compared to the solar composition is shown. A rich statistics measurement of these and other neutron-rich isotopes in the galactic flux yields information to the source of these particles. A computer simulation of the experiment was used to estimate the instrument resolution. The Cherenkov detector light collection efficiency, was calculated. Absorption of light in the radiator was considered to determine the optimum Cherenkov medium thickness. The experiment will determine the isotopic composition for the elements neon through argon in the energy range 300 to 800 MeV per nucleon
Aging Logarithmic Conformal Field Theory : a holographic view
We consider logarithmic extensions of the correlation and response functions
of scalar operators for the systems with aging as well as Schr\"odinger
symmetry. Aging is known to be the simplest nonequilibrium phenomena, and its
physical significances can be understood by the two-time correlation and
response functions. Their logarithmic part is completely fixed by the bulk
geometry in terms of the conformal weight of the dual operator and the dual
particle number.
Motivated by recent experimental realizations of Kardar-Parisi-Zhang
universality class in growth phenomena and its subsequent theoretical extension
to aging, we investigate our two-time correlation functions out of equilibrium,
which show several qualitatively different behaviors depending on the
parameters in our theory. They exhibit either growing or aging, i.e. power-law
decaying, behaviors for the entire range of our scaling time. Surprisingly, for
some parameter ranges, they exhibit growing at early times as well as aging at
later times.Comment: 1+26 pages, 15 figure
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