53,700 research outputs found
Synthesis and characterization of dioxidomolybdenum(VI) complexes with thiosemicarbazone ligands
The chemistry of thiosemicarbazone complexes of transition metals has been the subject of attention, primarily because of overgrowing biological properties. These activities have been correlated with their metal-chelating abilities and reductive capacity. The coordination chemistry of molybdenum receives special attention due to chemistry of its oxidation state, coordination number, ligating atom and their impact on structure and reactivity. To extend these observations, in this dissertation an attention is focused on the synthesis and characterization of new dioxidomolybdenum(VI) complexes featuring thiosemicarbazone ligands
Comment on "1/f noise in the Bak-Sneppen model"
Contrary to the recently published results by Daerden and Vanderzande [Phys.
Rev. E 53, 4723 (1996)], we show that the time correlation function in the
random-neighbor version of the Bak-Sneppen model can be well approximated by an
exponential giving rise to a 1/f2 power spectrum.Comment: 2 pages, 2 figure
Reformas estructurales para la sostenibilidad del gasto sanitario: un análisis del caso de España.
La sostenibilidad del gasto sanitario ha sido objeto de estudio en nuestro país en las últimas décadas, y con la llegada de la crisis da lugar a un nuevo panorama de inseguridad a la hora de mantener los servicios que ofrece nuestro sistema sanitario, con la misma calidad y eficiencia.
El análisis está orientado al estudio de la evolución del gasto sanitario, centrándose más tarde, en los factores que provocan su tendencia creciente, destacando el cambio demográfico que viviremos en un futuro cercano. Tras el análisis del gasto sanitario, profundizaremos en el estudio de las reformas, sus efectos, y recomendaciones para mejorar la situación en la que vivimos.Departamento de Economía AplicadaGrado en Economí
Cellular Automata Simulating Experimental Properties of Traffic Flows
A model for 1D traffic flow is developed, which is discrete in space and
time. Like the cellular automaton model by Nagel and Schreckenberg [J. Phys. I
France 2, 2221 (1992)], it is simple, fast, and can describe stop-and-go
traffic. Due to its relation to the optimal velocity model by Bando et al.
[Phys. Rev. E 51, 1035 (1995)], its instability mechanism is of deterministic
nature. The model can be easily calibrated to empirical data and displays the
experimental features of traffic data recently reported by Kerner and Rehborn
[Phys. Rev. E 53, R1297 (1996)].Comment: For related work see
http://www.theo2.physik.uni-stuttgart.de/helbing.html and
http://traffic.comphys.uni-duisburg.de/member/home_schreck.htm
A Statistical Treatment of the Gamma-Ray Burst "No Host Galaxy" Problem: II. Energies of Standard Candle Bursts
With the discovery that the afterglows after some bursts are coincident with
faint galaxies, the search for host galaxies is no longer a test of whether
bursts are cosmological, but rather a test of particular cosmological models.
The methodology we developed to investigate the original "no host galaxy"
problem is equally valid for testing different cosmological models, and is
applicable to the galaxies coincident with optical transients. We apply this
methodology to a family of models where we vary the total energy of standard
candle bursts. We find that total isotropic energies of E<2e52~erg are ruled
out while log(E)~53 erg is favored.Comment: To appear in Ap.J., 514, 15 pages + 7 figures, AASTeX 4.0. Revisions
are: additional author, updated data, and minor textual change
Properties of Ridges in Elastic Membranes
When a thin elastic sheet is confined to a region much smaller than its size
the morphology of the resulting crumpled membrane is a network of straight
ridges or folds that meet at sharp vertices. A virial theorem predicts the
ratio of the total bending and stretching energies of a ridge. Small strains
and curvatures persist far away from the ridge. We discuss several kinds of
perturbations that distinguish a ridge in a crumpled sheet from an isolated
ridge studied earlier (A. E. Lobkovsky, Phys. Rev. E. 53 3750 (1996)). Linear
response as well as buckling properties are investigated. We find that quite
generally, the energy of a ridge can change by no more than a finite fraction
before it buckles.Comment: 13 pages, RevTeX, acknowledgement adde
The von Karman equations, the stress function, and elastic ridges in high dimensions
The elastic energy functional of a thin elastic rod or sheet is generalized
to the case of an M-dimensional manifold in N-dimensional space. We derive
potentials for the stress field and curvatures and find the generalized von
Karman equations for a manifold in elastic equilibrium. We perform a scaling
analysis of an M-1 dimensional ridge in an M = N-1 dimensional manifold. A
ridge of linear size X in a manifold with thickness h << X has a width w ~
h^{1/3}X^{2/3} and a total energy E ~ h^{M} (X/h)^{M-5/3}. We also prove that
the total bending energy of the ridge is exactly five times the total
stretching energy. These results match those of A. Lobkovsky [Phys. Rev. E 53,
3750 (1996)] for the case of a bent plate in three dimensions.Comment: corrected references, 27 pages, RevTeX + epsf, 2 figures, Submitted
to J. Math. Phy
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