Pion scattering poles and chiral symmetry restoration

Using unitarized Chiral Perturbation Theory methods, we perform a detailed analysis of the $\pi\pi$ scattering poles $f_0(600)$ and $\rho(770)$ behaviour when medium effects such as temperature or density drive the system towards Chiral Symmetry Restoration. In the analysis of real poles below threshold, we show that it is crucial to extend properly the unitarized amplitudes so that they match the perturbative Adler zeros. Our results do not show threshold enhancement effects at finite temperature in the $f_0(600)$ channel, which remains as a pole of broad nature. We also implement T=0 finite density effects related to chiral symmetry restoration, by varying the pole position with the pion decay constant. Although this approach takes into account only a limited class of contributions, we reproduce the expected finite density restoration behaviour, which drives the poles towards the real axis, producing threshold enhancement and $\pi\pi$ bound states. We compare our results with several model approaches and discuss the experimental consequences, both in Relativistic Heavy Ion Collisions and in $\pi\to \pi\pi$ and $\gamma\to \pi\pi$ reactions in nuclei.Comment: 17 pages, 9 figures, final version to appear in Phys.Rev.D, added comments and reference

Using FPGA for visuo-motor control with a silicon retina and a humanoid robot

The address-event representation (AER) is a neuromorphic communication protocol for transferring asynchronous events between VLSI chips. The event information is transferred using a high speed digital parallel bus. This paper present an experiment based on AER for visual sensing, processing and finally actuating a robot. The AER output of a silicon retina is processed by an AER filter implemented into a FPGA to produce a mimicking behaviour in a humanoid robot (The RoboSapiens V2). We have implemented the visual filter into the Spartan II FPGA of the USB-AER platform and the Central Pattern Generator (CPG) into the Spartan 3 FPGA of the AER-Robot platform, both developed by authors.Unión Europea IST-2001-34124 (CAVIAR)Ministerio de Ciencia y Tecnología TIC-2003-08164-C03-0

Human NKG2D-ligands: cell biology strategies to ensure immune recognition

Immune recognition mediated by the activating receptor NKG2D plays an important role for the elimination of stressed cells, including tumors and virus-infected cells. On the other hand, the ligands for NKG2D can also be shed into the sera of cancer patients where they weaken the immune response by downmodulating the receptor on effector cells, mainly NK and T cells. Although both families of NKG2D-ligands, major histocompatibility complex class I-related chain (MIC) A/B and UL16 binding proteins (ULBPs), are related to MHC molecules and their expression is increased after stress, many differences are observed in terms of their biochemical properties and cell trafficking. In this paper, we summarize the variety of NKG2D-ligands and propose that selection pressure has driven evolution of diversity in their trafficking and shedding, but not receptor binding affinity. However, it is also possible to identify functional properties common to individual ULBP molecules and MICA/B alleles, but not generally conserved within the MIC or ULBP families. These characteristics likely represent examples of convergent evolution for efficient immune recognition, but are also attractive targets for pathogen immune evasion strategies. Categorization of NKG2D-ligands according to their biological features, rather than their genetic family, may help to achieve a better understanding of NKG2D-ligand association with disease

Levantamientos topográficos en la III Campaña de Excavaciones en Tell Mahuz - Iraq I

In the third campaign of the archaeological excavations performed in Tell Mahuz (September-October 2000), a group of Surveying engineers has taken part, whose aim has been the mapping of Tell and its environment. The surface to be represented exceeds 100 hectares. This article highlights the peculiarities to take into account when mapping an archaeological site, and it describes the fieldwork carried out during the campain

Petrophysical characterization of the Dolomitic Member of the Boñar Formation (Upper Cretaceous; Duero Basin, Spain) as a potential CO2 reservoir

La Formación Boñar (Cretácico Superior) es una sucesión carbonática que aflora al Norte de la Cuenca del Duero (España). Según datos previos, el Miembro Dolomítico de esta formación es el que muestra características petrográficas más favorables para almacenamiento geológico de CO2. El principal objetivo de este trabajo es el aporte de elementos de juicio que apoyen, clarifiquen y concreten –a un nivel de estudio preliminar– la potencialidad del Miembro Dolomítico de la Formación Boñar como roca almacén. La Formación Boñar (Cretácico Superior) es una sucesión carbonática que aflora al Norte de la Cuenca del Duero (España). Según datos previos, el Miembro Dolomítico de esta formación es el que muestra características petrográficas más favorables para almacenamiento geológico de CO2. El principal objetivo de este trabajo es el aporte de elementos de juicio que apoyen, clarifiquen y concreten –a un nivel de estudio preliminar– la potencialidad del Miembro Dolomítico de la Formación Boñar como roca almacén.Boñar Formation (Upper Cretaceous) is a mainly carbonate succession, which outcrops in the North of Duero Basin (Spain). According to the existing data, the Dolomitic Member of this formation appears to be the most suitable for geological storage of CO2. The main objective of this study is to find evidence to support, clarify and specify –at an initial level– the potential of the Dolomitic Member of the Boñar Formation as a geological reservoir. The study covers density, porosity and permeability tests on samples obtained from the outcrop of the succession near the village of Boñar (León). According to the analysis and interpretation of the mentioned petrophysical properties, the porosity of the Dolomitic Member is within the acceptable range for CO2 geological storage, but the permeability values are far too low. This minimizes the possibilities of the Dolomitic Member –and probably of the whole Boñar Formation– to become an appropriate CO2 reservoir

ZnO synthesis from Zn-C and alkaline spent batteries by alkaline leaching: properties and applications

6th EUCHEMS Chemistry Congress. Seville, Spain, 11th-19 th September 2016This report describes the leaching experiments to recover Zn from spent household Zn-C and alkaline batteries. Basic zinc carbonate Zn5(CO3)2(OH)6 nanoparticles have been successfully synthesized by the leaching of an ammoniacal ammonium carbonate solution of black mass. Zinc oxide (ZnO) were prepared by the thermal decomposition of basic zinc carbonate precursor. The synthesis of ZnO micro and nanostructures is carried out through the vapor solid growth process.Ministerio de Economía y Competitividad MINECO (Projects MAT 2012-31959 and CSD2009-00013) and MINECO/FEDER (MAT2015-65274-R; 2016-2019). This work has supported by the Envirobat España S.L.Peer reviewe

Next Reaction Method for Solving Dynamic Macroeconomic Models: A Growth Regressions Simulation

277-280Recent studies apply the Monte Carlo method to try to solve multiple data problems for dynamic macroeconomic models such as measurement errors, residue correlation, and omitted variables. This paper evaluates the estimate of economic growth regressions from the Solow model by applying the Next Reaction Method, similar to the Monte Carlo kinetic methods. Our results indicate that with the said algorithm the estimation of these models improves since they increase the levels of precision of the existing models simulated with Monte Carlo, achieving faster the convergence of the coefficients of the variables reduces the possible measurement errors and the level of deviations. These results can be very useful in their application in dynamic macroeconomic models, which help the estimation challenges of policymakers and other related stakeholders

Virtual reality training platform for flexible ureterorenoscopy interventions with a minimally invasive surgical robot

The total number of ureteroscopy (URS) interventions during the past years has dramatically increased due to the ongoing technological advances and the benefits associated with these techniques. However, the current URS procedure presents some drawbacks to urologic surgeons. The LITHOS project was created with the main objective of developing a surgical robotic system for flexible ureterorenoscopic lithotripsy interventions, offering a technological solution that meets the real needs of both patients and surgeons in this type of procedures. In this paper, a virtual reality environment for flexible ureterorenoscopy interventions is presented. The proposed environment provides a suitable training platform for surgeons manipulating the surgical robotic system

Solving non-uniqueness in agglomerative hierarchical clustering using multidendrograms

In agglomerative hierarchical clustering, pair-group methods suffer from a problem of non-uniqueness when two or more distances between different clusters coincide during the amalgamation process. The traditional approach for solving this drawback has been to take any arbitrary criterion in order to break ties between distances, which results in different hierarchical classifications depending on the criterion followed. In this article we propose a variable-group algorithm that consists in grouping more than two clusters at the same time when ties occur. We give a tree representation for the results of the algorithm, which we call a multidendrogram, as well as a generalization of the Lance and Williams' formula which enables the implementation of the algorithm in a recursive way.Comment: Free Software for Agglomerative Hierarchical Clustering using Multidendrograms available at http://deim.urv.cat/~sgomez/multidendrograms.ph

Late Glacial and Early Holocene human demographic responses to climatic and environmental change in Atlantic Iberia

Successive generations of hunter-gatherers of the Late Glacial and Early Holocene in Iberia had to contend with rapidly changing environments and climatic conditions. This constrained their economic resources and capacity for demographic growth. The Atlantic façade of Iberia was occupied throughout these times and witnessed very significant environmental transformations. Archaeology offers a perspective on how past human population ecologies changed in response to this scenario. Archaeological radiocarbon data are used here to reconstruct demographics of the region over the long term. We introduce various quantitative methods that allow us to develop palaeodemographic and spatio-temporal models of population growth and density, and compare our results to independent records of palaeoenvironmental and palaeodietary change, and growth rates derived from skeletal data. Our results demonstrate that late glacial population growth was stifled by the Younger Dryas stadial, but populations grew in size and density during the Early to Middle Holocene transition. This growth was fuelled in part by an increased dependence on marine and estuarine food sources, demonstrating how the environment was linked to demographic change via the resource base, and ultimately the carrying capacity of the environment. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.FCT: DL 57/2016/CP1361/CT0026info:eu-repo/semantics/publishedVersio