2,118 research outputs found
Scalar Field Dark Matter: head-on interaction between two structures
In this manuscript we track the evolution of a system consisting of two
self-gravitating virialized objects made of a scalar field in the newtonian
limit. The Schr\"odinger-Poisson system contains a potential with
self-interaction of the Gross-Pitaevskii type for Bose Condensates. Our results
indicate that solitonic behavior is allowed in the scalar field dark matter
model when the total energy of the system is positive, that is, the two blobs
pass through each other as should happen for solitons; on the other hand, there
is a true collision of the two blobs when the total energy is negative.Comment: 8 revtex pages, 11 eps figures. v2 matches the published version.
v2=v1+ref+minor_change
Interference pattern in the collision of structures in the BEC dark matter model: comparison with fluids
In order to explore nonlinear effects on the distribution of matter during
collisions within the Bose-Einstein condensate (BEC) dark matter model driven
by the Schr\"odinger-Poisson system of equations, we study the head-on
collision of structures and focus on the interference pattern formation in the
density of matter during the collision process. We explore the possibility that
the collision of two structures of fluid matter modeled with an ideal gas
equation of state also forms interference patterns and found a negative result.
Given that a fluid is the most common flavor of dark matter models, we conclude
that one fingerprint of the BEC dark matter model is the pattern formation in
the density during a collision of structures.Comment: 7 pages, 22 eps figure
Shape coexistence in Lead isotopes in the interacting boson model with Gogny energy density functional
We investigate the emergence and evolution of shape coexistence in the
neutron-deficient Lead isotopes within the interacting boson model (IBM) plus
configuration mixing with microscopic input based on the Gogny energy density
functional (EDF). The microscopic potential energy surface obtained from the
constrained self-consistent Hartree-Fock-Bogoliubov method employing the
Gogny-D1M EDF is mapped onto the coherent-state expectation value of the
configuration-mixing IBM Hamiltonian. In this way, the parameters of the IBM
Hamiltonian are fixed for each of the three relevant configurations (spherical,
prolate and oblate) associated to the mean field minima. Subsequent
diagonalization of the Hamiltonian provides the excitation energy of the
low-lying states and transition strengths among them. The model predictions for
the level energies and evolving shape coexistence in the considered
Lead chain are consistent both with experiment and with the indications of the
Gogny-EDF energy surfaces.Comment: 12 pages, 6 figures, 1 tabl
Scalar Field as Dark Matter in the Universe
We investigate the hypothesis that the scalar field is the dark matter and
the dark energy in the Cosmos, wich comprises about 95% of the matter of the
Universe. We show that this hypothesis explains quite well the recent
observations on type Ia supernovae.Comment: 4 pages REVTeX, 1 eps figure. Minor changes. To appear in Classical
and Quantum Gravit
Fission half-lives of super-heavy nuclei in a microscopic approach
A systematic study of 160 heavy and super-heavy nuclei is performed in the
Hartree-Fock-Bogoliubov approach with the finite range and density dependent
Gogny force with the D1S parameter set. We show calculations in several
approximations: with axially symmetric and reflexion symmetric wave functions,
with axially symmetric and non-reflexion symmetric wave functions and finally
some representative examples with triaxial wave functions are also discussed.
Relevant properties of the ground state and along the fission path are
thoroughly analyzed. Fission barriers, Q-factors and lifetimes with
respect to fission and -decay as well as other observables are
discussed. Larger configuration spaces and more general HFB wave functions as
compared to previous studies provide a very good agreement with the
experimental data.Comment: 26 pages, 15 figure
Spherical Scalar Field Halo in Galaxies
We study a spherically symmetric fluctuation of scalar dark matter in the
cosmos and show that it could be the dark matter in galaxies, provided that the
scalar field has an exponential potential whose overall sign is negative and
whose exponent is constrained observationally by the rotation velocities of
galaxies. The local space-time of the fluctuation contains a three dimensional
space-like hypersurface with surplus of angle.Comment: 5 REVTeX pages, no figures. Contains important suggestions provided
by the referee. Final version, to appear in Phys. Rev.
A MegaCam Survey of Outer Halo Satellites. VI: The Spatially Resolved Star Formation History of the Carina Dwarf Spheroidal Galaxy
We present the spatially resolved star formation history (SFH) of the Carina
dwarf spheroidal galaxy, obtained from deep, wide-field g,r imaging and a
metallicity distribution from the literature. Our photometry covers
deg, reaching up to times the half-light radius of Carina with a
completeness higher than at , more than one magnitude fainter
than the oldest turnoff. This is the first time a combination of depth and
coverage of this quality has been used to derive the SFH of Carina, enabling us
to trace its different populations with unprecedented accuracy. We find that
Carina's SFH consists of two episodes well separated by a star formation
temporal gap. These episodes occurred at old ( Gyr) and intermediate
(- Gyr) ages. Our measurements show that the old episode comprises the
majority of the population, accounting for of the stellar mass
within times the King tidal radius, while the total stellar mass derived
for Carina is , and the stellar
mass-to-light ratio . The SFH derived is consistent with no recent
star formation which hints that the observed blue plume is due to blue
stragglers. We conclude that the SFH of Carina evolved independently of the
tidal field of the Milky Way, since the frequency and duration of its star
formation events do not correlate with its orbital parameters. This result is
supported by the age/metallicity relation observed in Carina, and the gradients
calculated indicating that outer regions are older and more metal poor.Comment: Accepted in ApJ (22 pages, 13 figures
Osteoclast-mediated resorption primes the skeleton for successful integration during axolotl limb regeneration
Early events during axolotl limb regeneration include an immune response and the formation of a wound epithelium. These events are linked to a clearance of damaged tissue prior to blastema formation and regeneration of the missing structures. Here, we report the resorption of calcified skeletal tissue as an active, cell-driven, and highly regulated event. This process, carried out by osteoclasts, is essential for a successful integration of the newly formed skeleton. Indeed, the extent of resorption is directly correlated with the integration efficiency, and treatment with zoledronic acid resulted in osteoclast function inhibition and failed tissue integration. Moreover, we identified the wound epithelium as a regulator of skeletal resorption, likely releasing signals involved in recruitment/differentiation of osteoclasts. Finally, we reported a correlation between resorption and blastema formation, particularly, a coordination of resorption with cartilage condensation. In sum, our results identify resorption as a major event upon amputation, playing a critical role in the overall process of skeletal regeneration
Naturaleza internacional del arbitraje. Ley 1563 de 2012
El arbitraje es un mecanismo alternativo de solución de conflictos (MASC) mediante el cual las partes/resuelven sus diferencias ante un tribunal independiente, es decir, difieren a árbitros2. La solución de una controversia relativa a asuntos de libre disposición o aquellos que la ley autoriza. El arbitraje se rige a través de los principios de imparcialidad, idoneidad, celeridad, igualdad, oralidad, publicidad y contradicción.
Es un mecanismo hetero-compositivo, toda vez que es un tercero diferente a las partes quien se encarga de dirimir el conflicto; es oneroso, ya que se deben pagar los honorarios y gastos del tribunal para que se pueda adelantar el trámite; es excepcional, ya que las partes a través de un pacto arbitral han rechazado acudir a la justicia ordinaria para acudir a este mecanismo alternativo para solucionar su confrontación -si el pacto está contenido en una cláusula esta es autónoma del contrato-; es temporal dado que el tribunal cesa sus funciones cuando se presentan diversas causales como la expedición del laudo, vencimiento de termino, etc
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