Conservation Laws in Smooth Particle Hydrodynamics: the DEVA Code

We describe DEVA, a multistep AP3M-like-SPH code particularly designed to study galaxy formation and evolution in connection with the global cosmological model. This code uses a formulation of SPH equations which ensures both energy and entropy conservation by including the so-called \bn h terms. Particular attention has also been paid to angular momentum conservation and to the accuracy of our code. We find that, in order to avoid unphysical solutions, our code requires that cooling processes must be implemented in a non-multistep way. We detail various cosmological simulations which have been performed to test our code and also to study the influence of the \bn h terms. Our results indicate that such correction terms have a non-negligible effect on some cosmological simulations, especially on high density regions associated either to shock fronts or central cores of collapsed objects. Moreover, they suggest that codes paying a particular attention to the implementation of conservation laws of physics at the scales of interest, can attain good accuracy levels in conservation laws with limited computational resources.Comment: 36 pages, 10 figures. Accepted for publication in The Astrophysical Journa

Meta-stereotypes among women living homeless: Content, uniformity, and differences based on gender in Madrid, Spain

This paper examines the content and degree of uniformity of meta-stereotypes among women living homeless in Madrid, Spain, and the differences with their male counterparts. The study was conducted utilizing a structured interview with a representative sample of men living homeless (n=158) and a convenience sample of a similar size (n=138) of women living homeless. The results show that the meta?stereotypes of women living homeless in Madrid are characterized by mainly negative (e.g., consumers of alcohol, drug users, lazy, criminals) or indulgent (e.g., physically and psychologically worn out, rejected by society, sick) contents, with very limited positive (e.g., courteous, respectful, polite) contents, and a high degree of uniformity. There are no major differences in the content of meta?stereotypes of the female interviewees in terms of their age, academic background, motherhood, or nationality. Compared to men in the same situation, a larger percentage of women living homeless agree with negative and indulgent meta-stereotypes, and a smaller percentage agree with positive meta-stereotypes.Ministerio de Economía, Industria y Competitivida

Caracterización mecánica de pistas deportivas fabricadas con materiales procedentes de neumáticos fuera de uso (NFU)

Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.The European Framework Directive 2008/98/EC on waste established as priority reuse and recycling before other recovery alternatives. In this normative reference, one the main waste flows identified are the end-of-life tyres, as a material whose mechanical properties could provide advantage in the construction of new structures. This paper presents the mechanical characterization of a layer made with shredded tires out of use, inside a section of a sportive track which included a sand layer. The use of the shredded tires out of use provides special features related with elasticity and damping to the sportive surface. In order to do that, a new test based on UNE-14809 was designed. A number of tests were performed using different configuration of sand and shredded tires. From the results obtained, a numerical model was implemented in FEA software

The influence of the da Vinci surgical robot on electromagnetic tracking in a clinical environment

Robot-assisted surgery is increasingly used in surgery for cancer. Reduced overview and loss of anatomical orientation are challenges that might be solved with image-guided surgical navigation using electromagnetic tracking (EMT). However, the robot’s presence may distort the electromagnetic field, affecting EMT accuracy. The aim of this study was to evaluate the robot’s influence on EMT accuracy. For this purpose, two different electromagnetic field generators were used inside a clinical surgical environment: a table top field generator (TTFG) and a planar field generator (PFG). The position and orientation of sensors within the electromagnetic field were measured using an accurate in-house developed 3D board. Baseline accuracy was measured without the robot, followed by stepwise introduction of potential distortion sources (robot and robotic instruments). The absolute accuracy was determined within the entire 3D board and in the clinical working volume. For the baseline setup, median errors in the entire tracking volume within the 3D board were 0.9 mm and 0.3° (TTFG), and 1.1 mm and 0.4° (PFG). Adding the robot and instruments did not affect the TTFG’s position accuracy (p = 0.60), while the PFG’s accuracies decreased to 1.5 mm and 0.7° (p &lt; 0.001). For both field generators, when adding robot and instruments, accuracies inside the clinical working volume were higher compared to the entire tracking 3D board volume, 0.7 mm and 0.3° (TTFG), and 1.1 mm and 0.7° (PFG). Introduction of a surgical robot and robotic instruments shows limited distortion of the EMT field, allowing sufficient accuracy for surgical navigation in robotic procedures.</p

Biomimetic Ca-P coatings Incorporating bisphosphonates produced on starch-based degradable biomaterials

In this study, sodium clodronate, a well-known therapeutic agent from the family of bisphosphonates (BPs), is incorporated in a biomimetic calcium phosphate (CaP) coating, previously formed on the surface of a starch-based biomaterial by a sodium silicate methodology, as a strategy to develop a site-specific drug delivery system for bone tissue regeneration applications. The effects on the resulting CaP coatings were evaluated in terms of morphology, chemistry, and structure. The dissolution of Ca and P from the coating and the release profiles of sodium clodronate was also assessed. As a preliminary approach, this first study also aimed at evaluating the effects of this BP on the viability of a human osteoblastic cell line since there is still little information available on the interaction between BPs and this type of cells. Sodium clodronate was successfully incorporated, at different doses, in the structure of a biomimetic CaP layer previously formed by a sodium silicate process. This type of BPs had a stimulatory effect on osteoblastic activity, particularly at the specific concentration of 0.32 mg/mL. It is foreseen that these coatings can, for instances, be produced on the surface of degradable polymers and then used for regulating the equilibrium on osteoblastic/osteoclastic activity, leading to a controlled regenerative effect at the interface between the biomaterial and bone

Unifying thermodynamic and kinetic descriptions of single-molecule processes: RNA unfolding under tension

We use mesoscopic non-equilibrium thermodynamics theory to describe RNA unfolding under tension. The theory introduces reaction coordinates, characterizing a continuum of states for each bond in the molecule. The unfolding considered is so slow that one can assume local equilibrium in the space of the reaction coordinates. In the quasi-stationary limit of high sequential barriers, our theory yields the master equation of a recently proposed sequential-step model. Non-linear switching kinetics is found between open and closed states. Our theory unifies the thermodynamic and kinetic descriptions and offers a systematic procedure to characterize the dynamics of the unfolding processComment: 13 pages, 3 figure