2,600 research outputs found
¿Existe simetría en la artrosis vertebral?
X Congreso Nacional de Paleopatología. Univesidad Autónoma de Madrid, septiembre de 200
A dark energy multiverse
We present cosmic solutions corresponding to universes filled with dark and
phantom energy, all having a negative cosmological constant. All such solutions
contain infinite singularities, successively and equally distributed along
time, which can be either big bang/crunchs or big rips singularities.
Classicaly these solutions can be regarded as associated with multiverse
scenarios, being those corresponding to phantom energy that may describe the
current accelerating universe
Puberty in the Bronze Age: First application of a puberty estimation method to a prehistoric population
This is the peer reviewed version of the following article: Doe, Danielle M., et al. "Puberty in the Bronze Age: First application of a puberty estimation method to a prehistoric population". International Journal of Osteoarchaeology 29.6 (2019): 1091-1099, which has been published in final form at https://doi.org/10.1002/oa.2822. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsPuberty and adolescence represent a significant period of physical growth and maturation and a critical life stage in which children transition into adults within their societies. Numerous studies have observed a secular trend and have determined that puberty is now occurring earlier than in the past. This investigation represents the first application of a methodology for assessing the pubertal status of osteological remains to a prehistoric skeletal sample. Six Bronze Age adolescent skeletons from the Cerro de La Encantada archaeological site (Ciudad Real, Spain) were analysed. Prepubescence was observed at age 9 and the transition phase of the pubertal growth spurt at 15 years of age. These results were similar to those obtained from medieval, Industrial Revolution, and modern populations, both within and outside of the Iberian Peninsula. The similarity in the development of the Bronze Age adolescents to that of other past and contemporary populations suggests that the pubertal process has remained essentially unchanged across millennia until recent times. However, other interpretations, including the influence of a subpar developmental environment and potential methodological artefacts, are possible. Nevertheless, studies of this type provide important information about a crucial transitory period in human developmentThe Laboratorio de Poblaciones del Pasado (LAPP) has been supported by Projects HAR2016‐78036‐P, HAR2016‐74846‐P, HAR2017‐82755‐P, and HAR2017‐83004‐P (Spanish Government) and a grant (Ref. 38360) from the Leakey Foundatio
Quiste óseo aneurismático poliostótico
Se presenta un caso de quiste óseo aneurismático de localización bifocal,
correspondiente a una niña de 12 años de edad. La primera lesión diagnosticada se localizó
en la metáfisis proximal de la tibia izquierda y dos años más tarde, se descubrió una lesión
similar en el calcáneo derecho.
El estudio individualizado de estas lesiones no demuestra diferencias significativas respecto
a las clásicamente descritas para los quistes óseos aneurismáticos genuinos, monostó-
ticos.
En una amplia revisión bibliográfica sólo hemos podido encontrar un caso de localización
plurifocal.A bifocal aneurysmatic bone cyst presenting in a 12-year-old is
reported. The first lesion detected was situated in the proximal metaphysis of the
left tibia; the second lesion was diagnosed two years later in the right calcaneus.
Individual evaluation of these lesions discovered no significant differences with
respect to classical monostotic, true aneurysmatic bone cysts. An exhaustive review
of the literature yielded only one case exhibiting plurifocal location
Design of arbitrary optical filters in silicon-on-insulator using evanescently-coupled Bragg gratings
Spectral filters are experiencing an increasing demand in several applications of the silicon-
on-insulator (SOI) platform. Many works have demonstrated that arbitrary frequency
responses can be synthesized by apodizing the coupling coefficient profile of an integrated
Bragg grating. However, the high index contrast of the SOI platform hinders their
practical implementation, due to the difficulty of achieving the precise control required in
the Bragg strength. In this paper, we propose the implementation of spectral filters using
an architecture based on placing loading segments within the evanescent field region of a
photonic wire waveguide. The Bragg coupling coefficient can be accurately controlled by
simply moving the segments away from, or closer to, the waveguide core. The layerpeeling
algorithm, in conjunction with a Floquet-Bloch modal analysis, allows to determine
the spatial distribution of the segments that synthesizes the desired spectrum. The
proposed topology is verified by designing a filter with five arbitrary passbands.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
A graceful multiversal link of particle physics to cosmology
In this paper we work out a multiverse scenario whose physical
characteristics enable us to advance the following the conjecture that whereas
the physics of particles and fields is confined to live in the realm of the
whole multiverse formed by finite-time single universes, that for our
observable universe must be confined just in one of the infinite number of
universes of the multiverse when such a universe is consistently referred to an
infinite cosmic time. If this conjecture is adopted then some current
fundamental problems that appear when one tries to make compatible particle
physics and cosmology- such as that for the cosmological constant, the arrow of
time and the existence of a finite proper size of the event horizon- can be
solved.Comment: 10 pages, LaTe
Kinetics and Mechanism of Gold Dendrite Electroformation on C(0001) : Activation Energy for Gold Adatom Surface Diffusion
Au electrodeposition on C(0001) from aqueous solutions with different concentrations of AuCl3·HCl, at a constant ionic mass transport rate (jL), in the temperature range 275 ≤ T ≤ 313 K, results in the initial formation of nanometer-sized Au islands consisting of a central core and symmetrically distributed branches with the island fractal dimension Df = 1.6. For all values of T, the time dependence of the Au island radius fulfills a r ∝ tn relationship with n = 0.25 ± 0.05. At constant T, the density of Au islands (Ns) increases according to Ns ∝ jLX with X = 0.69 ± 0.03. At constant jL, the value of Ns decreases as T is increased, following an Arrhenius-type relationship. Kinetic data are consistent with a growth mechanism involving surface diffusion of Au adatoms from the island core towards branch tips. From the dependence of Ns on T at constant jL, the activation energy for Au adatom surface diffusion results in Ea* ≈ 11 Kcal/mol. This figure is slightly smaller than Ea* ≈ 14 Kcal/mol that has been reported for Au atom surface diffusion in Cl--ion free acid solutions.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada
Dissipation-driven generation of two-qubit entanglement mediated by plasmonic waveguides
We study the generation of entanglement between two distant qubits mediated
by the surface plasmons of a metallic waveguide. We show that a V-shaped
channel milled in a flat metallic surface is much more efficient for this
purpose than a metallic cylinder. The role of the misalignments of the dipole
moments of the qubits, an aspect of great importance for experimental
implementations, is also studied. A careful analysis of the quantum-dynamics of
the system by means of a master equation shows that two-qubit entanglement
generation is essentially due to the dissipative part of the effective
qubit-qubit coupling provided by the surface plasmons. The influence of a
coherent external pumping, needed to achieve a steady state entanglement, is
discussed. Finally, we pay attention to the question of how to get information
experimentally on the degree of entanglement achieved in the system.Comment: 13 pages, 12 figure
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