10,599 research outputs found
Acoustic Emission Monitoring of the Syracuse Athena Temple: Scale Invariance in the Timing of Ruptures
We perform a comparative statistical analysis between the acoustic-emission time series from the ancient Greek Athena temple in Syracuse and the sequence of nearby earthquakes. We find an apparent association between acoustic-emission bursts and the earthquake occurrence. The waiting-time distributions for acoustic-emission and earthquake time series are described by a unique scaling law indicating self-similarity over a wide range of magnitude scales. This evidence suggests a correlation between the aging process of the temple and the local seismic activit
"Universal" Distribution of Inter-Earthquake Times Explained
We propose a simple theory for the ``universal'' scaling law previously
reported for the distributions of waiting times between earthquakes. It is
based on a largely used benchmark model of seismicity, which just assumes no
difference in the physics of foreshocks, mainshocks and aftershocks. Our
theoretical calculations provide good fits to the data and show that
universality is only approximate. We conclude that the distributions of
inter-event times do not reveal more information than what is already known
from the Gutenberg-Richter and the Omori power laws. Our results reinforces the
view that triggering of earthquakes by other earthquakes is a key physical
mechanism to understand seismicity.Comment: 4 pages with two figure
Phenomenological implications of an alternative Hamiltonian constraint for quantum cosmology
In this paper we review a model based on loop quantum cosmology that arises
from a symmetry reduction of the self dual Plebanski action. In this
formulation the symmetry reduction leads to a very simple Hamiltonian
constraint that can be quantized explicitly in the framework of loop quantum
cosmology. We investigate the phenomenological implications of this model in
the semi-classical regime and compare those with the known results of the
standard Loop Quantum Cosmology.Comment: 10 pages, 7 figure
Small-scale phase separation in doped anisotropic antiferromagnets
We analyze the possibility of the nanoscale phase separation manifesting
itself in the formation of ferromagnetic (FM) polarons (FM droplets) in the
general situation of doped anisotropic three- and two-dimensional
antiferromagnets. In these cases, we calculate the shape of the most
energetically favorable droplets. We show that the binding energy and the
volume of a FM droplet in the three-dimensional (3D) case depend only upon two
universal parameters and , where and are effective
antiferromagnetic (AFM) exchange and hopping integrals, respectively. In the
two-dimensional (2D) case, these parameters have the form and . The most favorable shape of a
ferromagnetic droplet corresponds to an ellipse in the 2D case and to an
ellipsoid in the 3D case.Comment: 6 pages, 1 figure, RevTe
Adsorption and two-body recombination of atomic hydrogen on He-He mixture films
We present the first systematic measurement of the binding energy of
hydrogen atoms to the surface of saturated He-He mixture films.
is found to decrease almost linearly from 1.14(1) K down to 0.39(1) K, when the
population of the ground surface state of He grows from zero to
cm, yielding the value K cm
for the mean-field parameter of H-He interaction in 2D. The experiments
were carried out with overall He concentrations ranging from 0.1 ppm to 5 %
as well as with commercial and isotopically purified He at temperatures
70...400 mK. Measuring by ESR the rate constants and for
second-order recombination of hydrogen atoms in hyperfine states and we
find the ratio to be independent of the He content and to
grow with temperature.Comment: 4 pages, 4 figures, all zipped in a sigle file. Submitted to Phys.
Rev. Let
Long-Term Clustering, Scaling, and Universality in the Temporal Occurrence of Earthquakes
Scaling analysis reveals striking regularities in earthquake occurrence. The
time between any one earthquake and that following it is random, but it is
described by the same universal-probability distribution for any spatial region
and magnitude range considered. When time is expressed in rescaled units, set
by the averaged seismic activity, the self-similar nature of the process
becomes apparent. The form of the probability distribution reveals that
earthquakes tend to cluster in time, beyond the duration of aftershock
sequences. Furthermore, if aftershock sequences are analysed in an analogous
way, yet taking into account the fact that seismic activity is not constant but
decays in time, the same universal distribution is found for the rescaled time
between events.Comment: short paper, only 2 figure
Interplay between Heavy Fermions and Crystal Field Excitation in Kondo Lattices. Low-Temperature Thermodynamics and Inelastic Neutron Scattering Spectra of CeNiSn
The microscopic theory of interaction between the heavy fermions and the
crystal field excitations in Kondo lattices is presented. It is shown that the
heavy-fermion spectrum scaled by the Kondo temperature can be modified by
the crystal field excitations with the energy provided the
inequality is realized. On the base of general description of
excitation spectrum the detailed qualitative and quantitative explanation of
anisotropic inelastic neutron scattering spectra and low-temperature specific
heat of orthorhombic CeNiSn is given. The theory resolves the apparent
contradiction between the metallic conductivity and the gap-wise behavior of
thermodynamic properties and spin response of CeNiSn at low temperatures.Comment: 24 pages (LaTeX), 12 Postscript figures, submitted to Phys.Rev.
MASET: Multi-Attribute Software Evaluation Tool
Software developers and organizational users face many problems in identifying and evaluating features of software products. The products are complex, with numerous options, making design and development of applications time consuming and costly. With many users, it can be difficult to summarize user needs and priorities, let alone identify the functions and features that they need in the applications. Once functions and features are identified, a three stage least squares technique is used to identify and prioritize important features of software products. TheMulti-Attribute Software Evaluation Tool (MASET) can be used to evaluate existing software (commercial or in-house) or proposed features of new software products. This tool combines a series of functions into a software product that aids in the development of an evaluation questionaire, accepts input from respondents, prepares the input for the statistacal analysis package and uses an artifical intelligence module to analyze the result
Fermion Masses without Higgs: A Supersymmetric Technicolor Model
We propose a supersymmetric technicolor model in which the electroweak
symmetry breaking is communicated to the quarks and leptons by technicolored
-singlet scalars. When the technifermions condense, the quarks and
leptons of the third generation acquire mass. The fermions of the other
generations do not couple to the technicolored scalars but they receive masses
from radiative corrections involving superpartners. As a result, the mass
hierarchy between the fermion generations arises naturally. The model predicts
the CP asymmetries in meson decays and in transitions to be
smaller by two orders of magnitude than the ones predicted in the Standard
Model.Comment: 27 pages, latex, 4 figures (require feynman.tex). Changes in the
notation. An Appendix presenting the soft supersymmetric breaking terms is
added. Few more details included in the discussion of the flavor-changing
neutral current
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