Computational limit analysis for anchors and retaining walls

The computation of the bearing capacity of engineering structures commonly relays on results obtained for simple academic examples. Recent developments in computational limit analysis have allowed engineers to compute bounds of the bearing capacity of arbitrary geometries. We here extend these formulations to problems with practical interest such as retaining walls, anchors, or excavations with particular interface conditions. These situations require the special treatment of the contact conditions between different materials, or the modelling of joints and anchors. We demonstrate the potential of the resulting tool with some practical examples

Numerical modelling of multicellular dynamics

En este trabajo se desarrollar un modelo computacional que permite simular y predecir las deformaciones sucesivas que tienen lugar durante fases de la embriogénesis que han sido biológicamente bien detalladas. Las simulaciones resultantes tienen como objetivo reproducir la sincronización en la dinámica celular, las fuerzas que la dirigen, y la regulación genética y química del desarrollo embrionario. Los modelos numéricos tradicionales, basados mayoritariamente en elementos finitos, muestran dificultades en capturar tanto los cambios de geometría como las propiedades no lineales del material. El modelo propuesto hereda la partición física en células biológicas, y está consecuentemente basado en un medio discontinuo, en vez de un medio continuo. El modelo resuelve el equilibrio mecánico de las fuerzas intra- e inter-celulares, y para ello, combina estrategias de modelos centrados y de vértices, que a su vez son ampliados con ecuaciones de difusión/reacción que simulan y controlan la respuesta mecánica de la célula.This work aims to develop a computational model that can simulate and predict those successive deformations that biologically well understood cell shape changes take place in embryogenesis. The resulting simulations aim to reproduce the synchronised cell dynamics, the mechanical forces that drive them, and also the chemical and genetic regulation of embryo development. Traditional numerical models, which are mainly based on finite element techniques, are unable to capture the geometrical changes and the non-linear material properties. The proposed model inherits the physical partition in biological cells, and is thus based in a discontinuum rather than a continuum medium. The model aims to solve the mechanical equilibrium of intra- and inter-cellular forces, and in order to do so, it combines cell-centred and vertex strategies, which are in turn enhanced with diffusion-reaction equations that simulate and control the cell mechanical response.Peer Reviewe

Estudio de viabilidad para la emisión de títulos de deuda para financiar la ampliación del colegio balandra cruz del sur

empresas. Nuestra empresa a analizar, PREDUCA S.A, se ha desenvuelto en el sector educativo clase alta, manteniendo un prestigio por 17 años, lo cual la coloca como una de las mejores dentro de su estrato social. Su objetivo de reestructuración de pasivos y expansión futura, nos llevaron a establecer pautas para la utilización de nuevas herramientas de financiamiento. La emisión de obligaciones es una herramienta, conocida y utilizada en varios países incluidos el nuestro, que ha dado paso a un mayor desarrollo en el mercado de capitales ya que se muestra como una opción rentable al momento de invertir. Los análisis de los estados financieros de nuestra empresa en mención fueron factores cruciales para poder determinar la factibilidad de una emisión, además de una estrategia de introducción de este tipo de empresas en el mercado de valores, ya que de incursionar PREDUCA S.A. en este mercado sería la primera en su clase y sector. Las oportunidades y amenazas que una decisión como esta conlleva y los beneficios futuros asociados son tratados en nuestro estudio, a fin de dar al lector una visión del entorno de la empresa y proporcionar una guía de procedimientos a seguir en caso de realizarse una emisión de obligaciones. Todo ello asociado con la experiencia tanto al interior de nuestro país, la realidad que se ha vivido en los últimos años en nuestro mercado de obligaciones conjuntamente con lo sucedido en países latinoamericanos, nos muestra el escenario en que se desenvolvería PREDUCA S.A. al momento de emitir una obligación

Halo based reconstruction of the cosmic mass density field

We present the implementation of a halo based method for the reconstruction of the cosmic mass density field. The method employs the mass density distribution of dark matter haloes and its environments computed from cosmological N-body simulations and convolves it with a halo catalog to reconstruct the dark matter density field determined by the distribution of haloes. We applied the method to the group catalog of Yang etal (2007) built from the SDSS Data Release 4. As result we obtain reconstructions of the cosmic mass density field that are independent on any explicit assumption of bias. We describe in detail the implementation of the method, present a detailed characterization of the reconstructed density field (mean mass density distribution, correlation function and counts in cells) and the results of the classification of large scale environments (filaments, voids, peaks and sheets) in our reconstruction. Applications of the method include morphological studies of the galaxy population on large scales and the realization of constrained simulations.Comment: Accepted for publication in MNRA

Characterizing SL2S galaxy groups using the Einstein radius

We analyzed the Einstein radius, $\theta_E$, in our sample of SL2S galaxy groups, and compared it with $R_A$ (the distance from the arcs to the center of the lens), using three different approaches: 1.- the velocity dispersion obtained from weak lensing assuming a Singular Isothermal Sphere profile ($\theta_{E,I}$), 2.- a strong lensing analytical method ($\theta_{E,II}$) combined with a velocity dispersion-concentration relation derived from numerical simulations designed to mimic our group sample, 3.- strong lensing modeling ($\theta_{E,III}$) of eleven groups (with four new models presented in this work) using HST and CFHT images. Finally, $R_A$ was analyzed as a function of redshift $z$ to investigate possible correlations with L, N, and the richness-to-luminosity ratio (N/L). We found a correlation between $\theta_{E}$ and $R_A$, but with large scatter. We estimate $\theta_{E,I}$ = (2.2 $\pm$ 0.9) + (0.7 $\pm$ 0.2)$R_A$, $\theta_{E,II}$ = (0.4 $\pm$ 1.5) + (1.1 $\pm$ 0.4)$R_A$, and $\theta_{E,III}$ = (0.4 $\pm$ 1.5) + (0.9 $\pm$ 0.3)$R_A$ for each method respectively. We found a weak evidence of anti-correlation between $R_A$ and $z$, with Log$R_A$ = (0.58$\pm$0.06) - (0.04$\pm$0.1)$z$, suggesting a possible evolution of the Einstein radius with $z$, as reported previously by other authors. Our results also show that $R_A$ is correlated with L and N (more luminous and richer groups have greater $R_A$), and a possible correlation between $R_A$ and the N/L ratio. Our analysis indicates that $R_A$ is correlated with $\theta_E$ in our sample, making $R_A$ useful to characterize properties like L and N (and possible N/L) in galaxy groups. Additionally, we present evidence suggesting that the Einstein radius evolves with $z$.Comment: Accepted for publication in Astronomy & Astrophysics. Typos correcte

Assessing the impact of COVID-19 on liver cancer management (CERO-19)

Background & Aims: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems and it may have heavily impacted patients with liver cancer (LC). Herein, we evaluated whether the schedule of LC screening or procedures has been interrupted or delayed because of the COVID-19 pandemic. Methods: An international survey evaluated the impact of the COVID-19 pandemic on clinical practice and clinical trials from March 2020 to June 2020, as the first phase of a multicentre, international, and observational project. The focus was on patients with hepatocellular carcinoma or intrahepatic cholangiocarcinoma, cared for around the world during the first COVID-19 pandemic wave. Results: Ninety-one centres expressed interest to participate and 76 were included in the analysis, from Europe, South America, North America, Asia, and Africa (73.7%,17.1%, 5.3%, 2.6%, and 1.3% per continent, respectively). Eighty-seven percent of the centres modified their clinical practice: 40.8% the diagnostic procedures, 80.9% the screening programme, 50% cancelled curative and/or palliative treatments for LC, and 41.7% modified the liver transplantation programme. Forty-five out of 69 (65.2%) centres in which clinical trials were running modified their treatments in that setting, but 58.1% were able to recruit new patients. The phone call service was modified in 51.4% of centres which had this service before the COVID-19 pandemic (n = 19/37). Conclusions: The first wave of the COVID-19 pandemic had a tremendous impact on the routine care of patients with liver cancer. Modifications in screening, diagnostic, and treatment algorithms may have significantly impaired the outcome of patients. Ongoing data collection and future analyses will report the benefits and disadvantages of the strategies imple mented, aiding future decision-making

Electronic, vibrational, and thermodynamic properties of ZnS (zincblende and rocksalt structure)

We have measured the specific heat of zincblende ZnS for several isotopic compositions and over a broad temperature range (3 to 1100 K). We have compared these results with calculations based on ab initio electronic band structures, performed using both LDA and GGA exchange- correlation functionals. We have compared the lattice dynamics obtained in this manner with experimental data and have calculated the one-phonon and two-phonon densities of states. We have also calculated mode Grueneisen parameters at a number of high symmetry points of the Brillouin zone. The electronic part of our calculations has been used to investigate the effect of the 3d core electrons of zinc on the spin-orbit splitting of the top valence bands. The effect of these core electrons on the band structure of the rock salt modification of ZnS is also discussed.Comment: 33pages, 16 Figures, submitted to Phys. Rev.

M.A.B. Revestimientos vítreos con propiedades bactericidas y fungicidas

This report describes the mosaic M.A.B. (bactericide and fungicide) produced by Togama S.A. belonging to the group Fluidra S.A., which has been awarded with the Silver Alfa Award by the Spanish Society of Ceramics and Glass at the International Fair Cevisama 2012. This award recognizes the R & D efforts developed by Togama, SA, already started with participation in the Alpha Awards 2009 and 201

Radio continuum and near-infrared study of the MGRO J2019+37 region

(abridged) MGRO J2019+37 is an unidentified extended source of VHE gamma-rays originally reported by the Milagro Collaboration as the brightest TeV source in the Cygnus region. Its extended emission could be powered by either a single or several sources. The GeV pulsar AGL J2020.5+3653, discovered by AGILE and associated with PSR J2021+3651, could contribute to the emission from MGRO J2019+37, although extrapolation of the GeV spectrum does not explain the detected multi-TeV flux. Our aim is to identify radio and NIR sources in the field of the extended TeV source MGRO J2019+37, and study potential counterparts that could contribute to its emission. We surveyed a region of about 6 square degrees with the Giant Metrewave Radio Telescope (GMRT) at the frequency 610 MHz. We also observed the central square degree of this survey in the NIR Ks-band using the 3.5 m telescope in Calar Alto. Archival X-ray observations of some specific fields are included. VLBI observations of an interesting radio source were performed. We explored possible scenarios to produce the multi-TeV emission from MGRO J2019+37 and studied which of the sources could be the main particle accelerator. We present a catalogue of 362 radio sources detected with the GMRT in the field of MGRO J2019+37, and the results of a cross-correlation of this catalog with one obtained at NIR wavelengths, as well as with available X-ray observations of the region. Some peculiar sources inside the ~1 degree uncertainty region of the TeV emission from MGRO J2019+37 are discussed in detail, including the pulsar PSR J2021+3651 and its pulsar wind nebula PWN G75.2+0.1, two new radio-jet sources, the HII region Sh 2-104 containing two star clusters, and the radio source NVSS J202032+363158.Comment: 10 pages, 6 figures, 2 tables, accepted for publication in Astronomy and Astrophysic

Radio continuum and near-infrared study of the MGRO J2019+37 region

(abridged) MGRO J2019+37 is an unidentified extended source of VHE gamma-rays originally reported by the Milagro Collaboration as the brightest TeV source in the Cygnus region. Its extended emission could be powered by either a single or several sources. The GeV pulsar AGL J2020.5+3653, discovered by AGILE and associated with PSR J2021+3651, could contribute to the emission from MGRO J2019+37, although extrapolation of the GeV spectrum does not explain the detected multi-TeV flux. Our aim is to identify radio and NIR sources in the field of the extended TeV source MGRO J2019+37, and study potential counterparts that could contribute to its emission. We surveyed a region of about 6 square degrees with the Giant Metrewave Radio Telescope (GMRT) at the frequency 610 MHz. We also observed the central square degree of this survey in the NIR Ks-band using the 3.5 m telescope in Calar Alto. Archival X-ray observations of some specific fields are included. VLBI observations of an interesting radio source were performed. We explored possible scenarios to produce the multi-TeV emission from MGRO J2019+37 and studied which of the sources could be the main particle accelerator. We present a catalogue of 362 radio sources detected with the GMRT in the field of MGRO J2019+37, and the results of a cross-correlation of this catalog with one obtained at NIR wavelengths, as well as with available X-ray observations of the region. Some peculiar sources inside the ~1 degree uncertainty region of the TeV emission from MGRO J2019+37 are discussed in detail, including the pulsar PSR J2021+3651 and its pulsar wind nebula PWN G75.2+0.1, two new radio-jet sources, the HII region Sh 2-104 containing two star clusters, and the radio source NVSS J202032+363158.Comment: 10 pages, 6 figures, 2 tables, accepted for publication in Astronomy and Astrophysic