Analysis and Simulation of the Leg of an Hexapod Robot for Remote Exploration

The locomotion system is determined by the terrain conditions. The aim of this paper is to introduce the characteristics and simulation of a hexapod legged robot that can be easily used for exploration of abrupt and harsh terrains, Jike the Rio Tinto environment. A walking robot seems like the best option for this kind of terrain. Some of the advantages are that they do not need continuous terrain, they have less problems with sliding and they also have greater capacity to overcome obstacles as they produce Jess harm to the environment that the scientist wants to explore on the contrary when faced with mechanical design they present a design challenge, also in the static and dynamic analysis problem of a legged robot, there is a high complexity that has to be taken into account. This paper shows how to easily cope with the analysis of hexapod robot movement based on a design developed by the Center of Astrobiology INTA-CSIC for operation in RioTinto (Huelva - Spain)

The propagation of worldwide sector-specific shocks

Este artículo analiza el efecto agregado de shocks sectoriales y su propagación a través de las cadenas globales de producción. En concreto, el foco se sitúa sobre un caso en el que un mismo shock afecta de manera simultánea a una misma industria situada en diversos países. Así, nuestro análisis puede ser una herramienta útil en varios escenarios relevantes para las políticas económicas, como cambios en la regulación medioambiental o la implantación de nuevas tecnologías. Para ello, señalamos la necesidad de desviarse de los métodos tradicionales de análisis que asumen elasticidades de sustitución unitarias. Combinamos un marco teórico que permite valores discrecionales para las elasticidades de sustitución [Baqaee y Fahri (2019)] y utilizamos los datos de las Tablas Mundiales de Input-Output (World Input-Output Database) para cuantificar los vínculos internacionales entre sectores. Este escenario ilustra cómo, en presencia de complementariedades de insumos de producción, la interacción entre shocks simultáneos tiene efectos no lineales significativos en la composición sectorial y en el producto agregado. El impacto agregado de los shocks negativos (positivos) se amplifica (mitiga) significativamente cuando afectan simultáneamente a industrias cuyos procesos productivos están fuertemente interrelacionados. Así, nuestros resultados ponen de relieve que ignorar las complementariedades de producción lleva a subestimar enormemente las consecuencias agregadas de los shocks regulatorios o tecnológicos en industrias como la fabricación de vehículos o la producción de productos químicos. Por el contrario, los análisis estándar aproximan suficientemente bien el efecto en el caso de las industrias de servicios.This paper analyses the aggregate impact of industry-specific shocks and their propagation through global production networks. We focus on the case in which a common shock affects simultaneously the same industry across different countries. Thus, our analysis can be a useful tool for several policy-relevant scenarios, such as changes in environmental regulations or the implementation of new technologies. For that purpose, we highlight the importance of departing from standard linear models that assume unitary elasticities of substitution. We combine a theoretical framework of production networks with arbitrary elasticities of substitution (Baqaee & Farhi, 2019) and we make use of World Input-Output Database to account for international linkages. This setting illustrates how, in the presence of production input complementarities, the interaction between simultaneous shocks has significant non-linear effects on sectoral composition and aggregate output. The aggregate impact of negative (positive) shocks gets significantly amplified (mitigated) when they affect simultaneously industries with strong production linkages. Our results show that ignoring production complementarities leads to vastly underestimating the aggregate consequences of regulatory or technological shocks in industries like chemicals or vehicle manufacturing. In contrast, simultaneous shocks to services industries are well accounted for by standard measures

The propagation of worldwide sector-specific shocks

Summary of Banco de España Working Paper no. 221

Autonomous indoor ultrasonic positioning system based on a low-cost conditioning circuit

This is the author’s version of a work that was accepted for publication in Measurement. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Measurement, Vol. 45, Issue 3, (2012) DOI: http://dx.doi.org/10.1016/j.measurement.2011.12.002This work presents a low cost 3-D location system based on ultrasonics and implemented with low-cost FPGAs. The mobile nodes of the system use distance estimation to several anchor points in order to trilaterate their positions with an accuracy of few centimeters. The ultrasonic transducers are handled with an ad hoc conditioning circuit based on instrumental amplifiers which provides high amplification keeping low noise. The proposed system is autonomous so there is no need of an external PC or other devices. A prototype of the system has been attached to a mobile robot to check the viability of the location system in a real scenario.This work has been partially supported by the TEC2009-09871 project of the Ministerio de Ciencia e Innovacion, Spain

Low cost indoor ultrasonic positioning implemented in FPGA

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. A. Sánchez, S. Elvira, Á. de Castro, G. Gonzalez-de-Rivera, R. Ribalda, J. Garrido, "Low cost indoor ultrasonic positioning implemented in FPGA", 35th Annual Conference of IEEEIndustrial Electronics, 2009. IECON '09, Porto (Portugal), 2009, pp. 2709 - 2714This paper presents a low cost indoor ultrasonic-based positioning system. This system allows the mobile nodes of a Wireless Sensor Network to know their location using radiofrequency and ultrasonics. To achieve this goal, a matrix of transmitting anchor points is installed whereas the mobile nodes receive these transmitted signals and estimate the time-of-flight of the ultrasonic signals. Using two time-of-flight measurements and trilateration equations, the location of the mobile nodes can be inferred in a 2-D space.This work has been partially supported by the CCG08-UAM/TIC-4258 project of the Comunidad de Madrid and UAM

Distribución espacial y mapeo de curculio elephas gyllenhal en encina (quercus ilex l.)

Curculio elephases una de las plagas carpófagas más importantes en encinares y castañares en España. El presente trabajo se llevó a cabo durante un periodo de cuatro años en una dehesa del sur de España, y se ha estudiado la distribución espacial usando métodos clásicos (índices de infestación, índices de dispersión, ajustes a distribuciones estadísticas) y elaborando mapas de densidad larvaria. Nuestros principales resultados fueron: 1) alta incidencia de C. elephasen las encinas de la parcela de muestreo, presentándose de un 32 a un 57,4 % de las bellotas infestadas por el balanino; 2) los índices de dispersión, las distribuciones estadísticas y los mapas de densidad larvaria confirman que C. elephaspresenta una distribución agregada y una estabilidad espacio-temporal de sus poblaciones a lo largo del periodo de estudio; 3) relación directa entre la infestación y la densidad larvaria y el tamaño medio de las bellotas. Estos resultados indican que la distribución espacial anual de C. elephasfue heterogénea y que posiblemente esté relacionada, entre otros factores, con la distribución de las encinas con bellotas en las dehesas y de su calidad y grado de madureThe weevil, Curculio elephasis one of the most important carpophagous pest of holm oaks and chestnut trees in Spain. The present paper performed during a four year period in an economically exploited holm oak forest area in Southern Spain, investigated the chestnut weevil spatial distribution using both classic methods (infestation indices, dispersion indices, fitting to statistical distributions) and by elaborating larval density maps. Our main findings were: 1) a very high incidence of C. elephaswas detected on the holm oaks of the experimental plot, with 32-57.4 % of the acorns infested by the weevil; 2) dispersion indices, statistical distributions and larval density maps confirmed that C. elephashad an aggregated distribution and the spatio-temporal stability of its population over long term periods; 3) a direct relation was detected between the weevil infestation and larval density indices and the medium size of the acorns. These results indicate that the annual spatial ditribution of C. elephaswas heterogeneous and that it was possibly related, among other factors, to the distribution of holm-oak with acorns inside the forest and to their quality and degree of ripenes

Current ozone levels threaten gross primary production and yield of Mediterranean annual pastures and nitrogen modulates the response

Pastures are among the most important ecosystems in Europe considering their biodiversity and dis- tribution area. However, their response to increasing tropospheric ozone (O 3 ) and nitrogen (N) deposi- tion, two of the main drivers of global change, is still uncertain. A new Open-Top Chamber (OTC) experiment was performed in central Spain, aiming to study annual pasture response to O 3 and N in close to natural growing conditions. A mixture of six species of three representative families was sowed in the fi eld. Plants were exposed for 40 days to four O 3 treatments: fi ltered air, non- fi ltered air (NFA) repro- ducing ambient levels and NFA supplemented with 20 and 40 nl l � 1 O 3 . Three N treatments were considered to reach the N integrated doses of “ background ” , þ 20 or þ 40 kg N ha � 1 . Ozone signi fi cantly reduced green and total aboveground biomass (maximum reduction 25%) and increased the senescent biomass (maximum increase 40%). Accordingly, O 3 decreased community Gross Primary Production due to both a global reduction of ecosystem CO 2 exchange and an increase of ecosystem respiration. Nitrogen could partially counterbalance O 3 effects on aboveground biomass when the levels of O 3 were moderate, but at the same time O 3 exposure reduced the fertilization effect of higher N availability. Therefore, O 3 must be considered as a stress factor for annual pastures in the Mediterranean areas

Scaling of the coercivity with the geometrical parameters in epitaxial Fe antidot arrays

We studied a series of square lattice antidot arrays, with diameter and lattice parameter from hundreds of nanometers to some microns, fabricated using two lithography techniques in epitaxial Fe(001) films. The coercivity increase of each array with respect to its base film can be scaled to a simple geometric parameter, irrespective of the lithography technique employed. Magnetic transmission x-ray microscopy studies, in arrays fabricated on polycrystalline Fe films deposited on silicon nitride membranes, evidenced the propagation of reversed domains from the edges of the arrays, in agreement with the coercivity analysis of the epitaxial arrays and with micromagnetic models

Role of the polymorphic IL-1B, IL-1RN and TNF-A genes in distal gastric cancer in Mexico

Several cytokine gene polymorphisms have been associated with increased risk of distal gastric cancer (GC) and its precursor histological markers in Caucasian, Asian and Portuguese populations although little is known about their role in other ethnic groups. Our study investigates the role of the IL-1B-31, IL-1RN and TNF-A-308 gene polymorphisms as risk factors for the development of GC in a Mexican population. We studied 278 patients who were enrolled at the Hospital Universitario Dr. José Eleuterio González, Universidad Auto´noma de Nuevo Leo´n. The subjects were divided into 2 groups. Sixty-three patients with histologically confirmed distal GC (mean age 58.8 years, range 22–84, F:M 0.56), and 215 patients with no evidence of distal or proximal GC (mean age 56.1 years, range 18–92, F:M 1.17). The IL-1B-31 and the TNF-A-308 polymorphisms were determined by PCR-RFLP and pyrosequencing, respectively, in all cases and controls. The VNTR polymorphism in intron 2 of the 1L-1RN gene was typed by PCR in 25 cases and 201 controls. The H. pylori status was determined by histology, rapid urease test, culture and serology for non-cancer controls and by histology for the GC cases. The carriage of the proinflammatory IL-1B-31*Callele was associated with increased risk of distal GC (odds ratio [OR] 7.63, 95% confidence interval [CI] 1.73-46.94, p 0.003). When cases and controls were matched by age and gender, the OR value was higher (OR 8.05, 95% CI 1.8 –50.22, p 0.001). When only H. pylori GC cases and controls were compared, the OR value was 7.8 (95% CI 1.05–161.8, p 0.04). No association was found between any of the other polymorphisms studied and distal GC. In this Mexican population, the IL-1B proinflammatory genotype increases the risk of distal GC. These findings are similar to previous reports in Caucasian populations and underscore the importance of cytokine gene polymorphisms in the development of distal GC

Magnetic instabilities along the superconducting phase boundary of Nb/Ni multilayers

We report vibrating reed and superconducting quantum interference device magnetometer data that exhibit prominent dips or oscillations of the superconducting (SC) onset temperature, Delta T(C)(H)approximate to 0.01-0.7 K, for a [Nb(23 nm)/Ni(5 nm)](5) multilayer (ML) in dc magnetic fields applied nearly parallel to the ML plane. The vibrating reed data exhibit reproducible structures below T(C) that may reflect multiple SC transitions, but they are sensitive to ac field amplitude and dc field orientation. This striking behavior poses challenges for theoretical and experimental investigations of interfaces between SC and ferromagnetic layers that involve magnetic pair breaking effects, "pi phase shifts" of the SC order parameter, and exotic ("LOFF") pairing states. Alternatively, the anomalies may mark dynamical instabilities within a confined, strongly anisotropic Abrikosov vortex lattice