11,239 research outputs found
Apsidal motion in massive close binary systems. I. HD 165052 an extreme case?
We present a new set of radial-velocity measurements of the spectroscopic
binary HD 165052 obtained by disentangling of high-resolution optical spectra.
The longitude of the periastron (60 +- 2 degrees) shows a variation with
respect to previous studies. We have determined the apsidal motion rate of the
system (12.1 +- 0.3 degree/yr), which was used to calculate the absolute masses
of the binary components: M_1 = 22.5 +- 1.0 and M_2 = 20.5 +- 0.9 solar masses.
Analysing the separated spectra we have re-classified the components as O7Vz
and O7.5Vz stars
DBpedia's triple pattern fragments: usage patterns and insights
Queryable Linked Data is published through several interfaces, including SPARQL endpoints and Linked Data documents. In October 2014, the DBpedia Association announced an official Triple Pattern Fragments interface to its popular DBpedia dataset. This interface proposes to improve the availability of live queryable data by dividing query execution between clients and servers. In this paper, we present a usage analysis between November 2014 and July 2015. In 9 months time, the interface had an average availability of 99.99 %, handling 16,776,170 requests, 43.0% of which were served from cache. These numbers provide promising evidence that low-cost Triple Pattern Fragments interfaces provide a viable strategy for live applications on top of public, queryable datasets
Partially ordered models
We provide a formal definition and study the basic properties of partially
ordered chains (POC). These systems were proposed to model textures in image
processing and to represent independence relations between random variables in
statistics (in the later case they are known as Bayesian networks). Our chains
are a generalization of probabilistic cellular automata (PCA) and their theory
has features intermediate between that of discrete-time processes and the
theory of statistical mechanical lattice fields. Its proper definition is based
on the notion of partially ordered specification (POS), in close analogy to the
theory of Gibbs measure. This paper contains two types of results. First, we
present the basic elements of the general theory of POCs: basic geometrical
issues, definition in terms of conditional probability kernels, extremal
decomposition, extremality and triviality, reconstruction starting from
single-site kernels, relations between POM and Gibbs fields. Second, we prove
three uniqueness criteria that correspond to the criteria known as bounded
uniformity, Dobrushin and disagreement percolation in the theory of Gibbs
measures.Comment: 54 pages, 11 figures, 6 simulations. Submited to Journal of Stat.
Phy
Dry anaerobic digestion of organic waste: A review of operational parameters and their impact on process performance.
open access articleDry digestion is a suitable technology for treating organic wastes with varying composition such as the organic
fraction of municipal solids waste. Yet, there is a need for further research to overcome some of the disadvantages
associated with the high total solids content of the process. Optimisation of inoculum to substrate
ratio, feedstock composition and size, liquid recirculation, bed compaction and use of bulking agents are some of
the parameters that need further investigation in batch dry anaerobic digestion, to limit localised inhibition
effects and avoid process instability. In addition, further attention on the relation between feedstock composition,
organic loading rate and mixing regimes is required for continuous dry anaerobic digestion systems. This
paper highlights all the areas where knowledge is scarce and value can be added to increase dry anaerobic
digestion performance and expansion
Distorted Heisenberg Algebra and Coherent States for Isospectral Oscillator Hamiltonians
The dynamical algebra associated to a family of isospectral oscillator
Hamiltonians is studied through the analysis of its representation in the basis
of energy eigenstates. It is shown that this representation becomes similar to
that of the standard Heisenberg algebra, and it is dependent of a parameter
. We name it {\it distorted Heisenberg algebra}, where is the
distortion parameter. The corresponding coherent states for an arbitrary
are derived, and some particular examples are discussed in full detail. A
prescription to produce the squeezing, by adequately selecting the initial
state of the system, is given.Comment: 21 pages, Latex, 3 figures available as hard copies upon request from
the first Autho
Extended WKB method, resonances and supersymmetric radial barriers
Semiclassical approximations are implemented in the calculation of position
and width of low energy resonances for radial barriers. The numerical
integrations are delimited by t/T<<8, with t the period of a classical particle
in the barrier trap and T the resonance lifetime. These energies are used in
the construction of `haired' short range potentials as the supersymmetric
partners of a given radial barrier. The new potentials could be useful in the
study of the transient phenomena which give rise to the Moshinsky's diffraction
in time.Comment: 12 pages, 4 figures, 3 table
Poisson approximations for the Ising model
A -dimensional Ising model on a lattice torus is considered. As the size
of the lattice tends to infinity, a Poisson approximation is given for the
distribution of the number of copies in the lattice of any given local
configuration, provided the magnetic field tends to and the
pair potential remains fixed. Using the Stein-Chen method, a bound is given
for the total variation error in the ferromagnetic case.Comment: 25 pages, 1 figur
Beyond conventional factorization: Non-Hermitian Hamiltonians with radial oscillator spectrum
The eigenvalue problem of the spherically symmetric oscillator Hamiltonian is
revisited in the context of canonical raising and lowering operators. The
Hamiltonian is then factorized in terms of two not mutually adjoint factorizing
operators which, in turn, give rise to a non-Hermitian radial Hamiltonian. The
set of eigenvalues of this new Hamiltonian is exactly the same as the energy
spectrum of the radial oscillator and the new square-integrable eigenfunctions
are complex Darboux-deformations of the associated Laguerre polynomials.Comment: 13 pages, 7 figure
Tratamiento de la artropatía crónica hemofílica mediante inyecciones intraarticulares de cortisona
Se evaluaron las historias clínicas de 34 pacientes hemofílicos con artropatía crónica
severa (25 grado III y 9 grado IV), todos ellos con deformidades axiales, atrofia muscular y limitación
del movimiento articular (31 rodillas, 2 tobillos y 2 hombros), a quienes se les inyectó intraarticularmcnte
entre 1 y 9 dosis de cortisona de liberación prolongada con intervalos de 3 semanas.
Se les realizó una evaluación subjetiva y objetiva en base a los siguientes parámetros: bueno: no dolor,
incremento en los rangos de movimiento y total integración a las actividades de la vida diaria;
regular: disminución del dolor, igual rango de movilidad y actividades de la vida diaria limitadas, y
malo: persistencia del dolor, disminución de los rangos articulares y gran limitación para las actividades
de la vida diaria. En la evaluación subjetiva obtuvimos 19 pacientes con buenos resultados,
12 regulares y 4 malos; en la evaluación objetiva obtuvimos 22 pacientes con buenos resultados, 9 regulares
y 4 malos. Según los resultados obtenidos, la cortisona intraarticular parece ser un excelente
tratamiento paliativo en la artropatía crónica hemofílica.Thirty four patients with chronic haemophilic arthropathy (25 grade III and 9 grade
IV), having all axial deformities, muscular atrophy, and limitation of range of motion in the joint
(31 knees, 2 ankles and 2 shoulders) were injected intrarticulary at 3 weeks interval with a long
standing cortisone from 1 to 9 injections. Subjective and objective evaluation parameters were
assessed considering as good no pain, increase range of motion and normal activity of daily life;
fair with less pain, same range of motion and slight diminution of activity of daily life; and bad with
persistence of pain, less range of motion and greater diminution of activity. We obtained in subjective
evaluation 19 good results, 12 fair, and 4 bad; in objective evaluation we obtained 22 good
results, 9 fair, and 4 bad. In conclusion, intrarticular cortisone seems to be a reliable treatment of
chronic haemophilic arthropathy
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