A New Algorithm for the Evaluation of the Elastic Forces in the Absolute Nodal Coordinate Formulation

The use of the Absolute Nodal Coordinate Formulation (ANCF) to model flexible multibody systems leads to a system of equations in which the mass matrix is constant. Among other advantages of the ANCF, as the simplicity of the formulation of joint constraint, the constancy of the mass matrix is specially useful since it implies that the mass matrix is calculated once before the analysis and stored as a invariant quantity. On the other hand, the evaluation of the elastic forces has been considered as a difficult task since they result in large nonlinear functions. Both linear and nonlinear formulations based on either Continuum Mechanics or Timoshenko/Euler-Bernoulli approaches have been supposed to lead to the same level of complexity of the elastic force function. The evaluation of the elastic forces when using a nonlinear Continuum Mechanics approach requires, as presented in the literature, the integration over the volume of the element. However, it can be shown that this integration can be avoided for every evaluation since there is a closed form of the elastic force function that can be obtained before the simulation. Finite elements based on ANCF have such a large number of nodal coordinate (24 and 48 for three-dimensional beams and plates, respectively) that the search for a closed form of the elastic force function becomes difficult and costly. This paper presents a set of constant matrices that are integrated in advance (before simulation) and allows the evaluation of the elastic forces without the integration over the volume of the element suggested in the literature. In addition, the amount of data that has to be stored in order to evaluate the function is reduced. These constant matrices together with the mass matrix complete the set of invariants of the ANCF that allows an acceleration of simulations. Numerical simulations comparing CPU time and number of arithmetic operations carried out when these invariant matrices are used with those carried out when they are not used, support the convenience of their use.Ministerio de Ciencia y Tecnología DPI2000-056

Respuestas de alimentación de Scolytus scolytus a extractos del floema de ramillas de olmo

Feeding responses by Scolytus scolytus were tested using elm twig bark extracts in a laboratory bioassay. One to 4- years-old elm twigs or small branches were sampled in spring and their bark extracted separately with methanol and with a mixture of petroleum ether and diethyl ether (1:1) as solvents. Bark extracts were tested in a two choice feeding bioassay consisting of two polyurethane discs placed in a 10 cm diameter Petri dish. Extracts were applied onto the discs and the amount of disc eaten by ten freshly emerged S. scolytus adults was recorded after 24 hours. Ten U. minor, two U. laevis, six U. glabra, three Dutch hybrids (European x Asiatic) and one U. pumila trees were tested in several comparisons. Discs with extracts from both U. laevis trees were significantly less eaten than those from U. pumila or from U. minor trees in two choice tests. Similarly, extracts from all U. glabra trees received less feeding than those from U. minor. On the contrary, S. scolytus showed no difference in feeding between U. pumila and U. minor extracts, and similarly for Dutch hybrids in comparison with two U. minor clones. Again, beetles preferred to feed on Dutch hybrid extracts better than in those from U. laevis. Significant intraspecific differences in feeding were obtained in U. minor. One of the U. minor clones resulted less chosen when compared to other four trees. Extracts from a dying U. minor tree received more feeding than those from a healthy tree. Comparisons were also made between bark extracts from 2-to 4-year-old vs. current-year twigs within the same trees. In one of the four U. minor tested, a significant preference for the older twig extracts was recorded.Se estudió la respuesta de alimentación de S. scolytus a extractos del floema de ramillas de olmo en bioensayos de laboratorio. Se muestrearon en primavera ramillas de olmo de uno a cuatro años de edad y su floema fue extraído independientemente con metanol o con una mezcla de eter de petróleo y eter dietílico (1:1). Los extractos del floema se evaluaron en un bioensayo de doble elección consistente en dos discos de poliuretano dispuestos en una placa Petri de 10 cm de diámetro. Se aplicaron los extractos a los discos y se midió la superficie de disco comida por diez adultos recién emergidos de S. scolytus durante 24 h. Se ensayaron diez U. minor, dos U. laevis, seis U. glabra, tres híbridos holandeses (europeo x asiático) y un U. pumila en diversas comparaciones. Los discos con extractos de ambos U. laevis fueron significativamente menos comidos que aquéllos con los de U. pumila o de U. minor. Igualmente, los extractos de todos los U. glabra recibieron menor alimentación que aquéllos de U. minor. Por el contrario, S. scolytus no mostró preferencias entre los extractos de U. minor y de U. pumila, e igualmente, entre los de U. minor y los de híbridos holandeses. Nuevamente, los escolítidos prefirieron alimentarse menos de los extractos de U. laevis que de los híbridos holandeses. Se encontraron diferencias intraespecíficas significativas en U. minor. Uno de los clones de U. minor resultó menos preferido cuando se le comparó con otros cuatro árboles. Los extractos de un U. minor moribundo recibieron mayor alimentación que los de un árbol sano. Se realizaron comparaciones entre los extractos del floema de ramillas de 2 a 4 años de edad y de ramillas del año en curso de un mismo árbol. En uno de cuatro U. minor ensayados se observó una preferencia significativa por los extractos de las ramillas más viejas

Experimental estimation of the residual fatigue life of in-service wind turbine bolts

This study presents an experimental methodology aimed at estimating the residual fatigue life of in-service wind turbine bolts. The main objective is to assess the residual life of the bolts to plan their replacement and to avoid unexpected breakages of wind turbine blade connections. To develop the methodology, M16 bolts of quality 10.9 with controlled predamage were used, simulating in-service operating conditions. The fatigue tests were carried out taking care to place the nut at the point on the bolt that produces the highest damage at the same point where the predamage was performed. In addition, the influence of a possible angular positioning error on the residual fatigue life has been investigated. The residual fatigue life is estimated from the difference in fatigue life of new bolt tests and the fatigue life of predamaged bolt tests, simulating service conditions. Special care has been taken to guarantee that the most damaged zone of the bolt in service is also in the position that produces the highest damage during tests. An experimental procedure for determining the fatigue life of a new bolt from tests conducted on a bolt under the same operating conditions was developed. The developed methodology has been applied to M20 bolts belonging to real turbines in service

Componentes de la corteza del olmo y su posible influencia en la alimentación de los escolítidos

In order to better understand the chemical factors involved in the host feeding selectivity by Scolytus, components were extracted from elm bark and studied. Sampled trees were located in an elm stand that survived the Dutch twig elm disease pandemia, and from elm clones from throughout the Iberian Peninsula. The main samples studied were from Ulmus minor, and the other samples from U. pumila, U. laevis and several hybrids. The main compounds in the extracts obtained from current-year twigs were aliphatic hydrocarbons (particularly heptacosane and nonacosane) and from 2- to 4-year-old stems were triterpenes. Three of the triterpenes were identified for the first time in Ulmus (lupenol, alnulin, and ilexol) and two in Ulmaceae (moretenol and betulin). Differences occurred in the compounds isolated from U. minor from the two locations, and between species.Se analizaron los componentes de la corteza de ramillas de olmos, a fin de determinar los factores químicos involucrados en la selección, por parte de los escolítidos del olmo (Scolytus), de árboles para su alimentación. Las muestras fueron recogidas en árboles de una olmeda que ha sobrevivido a la pandemia de grafiosis y de ejemplares de distintas procedencias de la península Ibérica en un banco clonal. La principal especie estudiada fue Ulmus minor. Se tomaron además muestras de U. pumila, U. laevis y diversos híbridos. Los compuestos más abundantes en los extractos obtenidos de ramillas del año en curso fueron hidrocarburos alifáticos (principalmente heptacosano y nonacosano) y en las ramillas de 2º a 4º año triterpenos pentacíclicos. Tres de los triterpenos (lupenol, alnulina e ilexol) fueron identificados por primera vez en Ulmus y dos (moretenol y betulina) en Ulmaceae. Se observaron diferencias en los compuestos detectados en U. minor de las dos localizaciones así como entre especies

Diseño y simulación de un actuador de rigidez variable

XIX Congreso Nacional de Ingeniería Mecánica (CNIM 2012), Castellón, 14-16 de noviembre de 2012Los actuadores de rigidez variable se han desarrollado como una alternativa a los actuadores convencionales en diversas aplicaciones, como son entre otras los robots de servicio y los robots caminantes. El diseño mecánico de estos actuadores debe dar solución a nuevas necesidades que no eran tenidas en consideración en los actuadores rígidos, como la reducción del daño en caso de impacto o el ajuste de la frecuencia natural del sistema. Han sido muy diversas las soluciones propuestas hasta el momento, caracterizadas por el tipo de mecanismo implementado para variar la rigidez y posición de la articulación. En este trabajo se presenta un nuevo diseño de actuador basado en transmisión por cables, en el que un primer motor controla la posición de equilibrio del eslabón y un segundo motor se encarga de variar la rigidez de la articulación. Además, se ha simulado una situación de impacto hombre-robot para estudiar su contribución en la reducción del daño en hombre y robot.This work has been supported by the CAM Project S2009/DPI-1559/ROBOCITY2030 II, developed by the research team RoboticsLab at the University Carlos III of Madrid

Correlaciones fenotípicas, genéticas y ambientales en cucurbita moschata duch. ex poir

El estudio estimó las correlaciones fenotípicas, genéticas y ambientales entre doce caracteres agronómicos en dos dialélicos de zapallo (uno entre cinco variedades y otro entre cinco líneas S1, originadas de las anteriores). Se usó un diseño en bloques completos al azar con 15 tratamientos (5 progenitores + 10 cruzamientos F1) para cada dialélico y cinco repeticiones. Los resultados señalaron mayor estimación de las correlaciones (en magnitud y significancia estadística) a favor del dialélico de líneas S1. Las correlaciones genéticas fueron superiores a las fenotípicas y las ambientales. La producción por planta (PFP) presentó las correlaciones parciales fenotípicas y genéticas más altas con el peso por fruto (PPF) y el número de frutos por planta (NFP) (rPF y rPG and gt; 0.80). El PPF y NFP pueden usarse como criterios de selección para la obtención de cultivares de altos rendimientos en C. moschata. ABSTRACT Phenotypic, genotypic and environmental correlations in Cucurbita moschata Duch. Ex Poir. The study evaluated phenotypic, genotypic and environmental correlations among 12 agronomy characters, in two set diallelic from five parents each one. The first set from five open pollinated varieties and the second one from five self-pollinated lines S1, obtained from the previous varieties. The two experiments were in completely randomized blocks with five replications. A higher estimation of correlation (in magnitude and statistical significance) was observed in favor of the S1 lines diallelic. The genetic correlations were higher than the phenotypic and environmental correlations. The plant yield (PFP) showed the highest partial phenotypic and genetic correlations with the fruit weight (PPF) and fruits per plant (NFP) (rPF and rPG and gt; 0.80). It is suggested to use the PPF and NFP as selection criteria for breeding of C. moschata for development of high yield cultivars. Key words: Calabaza (cucurbita), genetic correlation, agronomic characteristics

Extracellular vesicles from Mycobacterium tuberculosis-infected neutrophils induce maturation of monocyte-derived dendritic cells and activation of antigen-specific Th1 cells

Tuberculosis remains one of the leading public health problems in the world. The mechanisms that lead to the activation of the immune response against Mycobacterium tuberculosis have been extensively studied, with a focus on the role of cytokines as the main signals for immune cell communication. However, less is known about the role of other signals, such as extracellular vesicles, in the communication between immune cells, particularly during the activation of the adaptive immune response. In this study, we determined that extracellular vesicles released by human neutrophils infected with M. tuberculosis contained several host proteins that are ectosome markers. In addition, we demonstrated that extracellular vesicles released by human neutrophils infected with M. tuberculosis released after only 30 min of infection carried mycobacterial antigens and pathogen-associated molecular patterns, and we identified 15 mycobacterial proteins that were consistently found in high concentrations in extracellular vesicles released by human neutrophils infected with M. tuberculosis; these proteins contain epitopes for CD4 T-cell activation. We found that extracellular vesicles released by human neutrophils infected with M. tuberculosis increased the expression of the costimulatory molecule CD80 and of the coinhibitory molecule PD-L1 on immature monocyte-derived dendritic cells. We also found that immature and mature dendritic cells treated with extracellular vesicles released by human neutrophils infected with M. tuberculosis were able to induce IFN-γ production by autologous M. tuberculosis antigen-specific CD4 T cells, indicating that these extracellular vesicles acted as antigen carriers and transferred mycobacterial proteins to the antigen-presenting cells. Our results provide evidence that extracellular vesicles released by human neutrophils infected with M. tuberculosis participate in the activation of the adaptive immune response against M. tuberculosis.This work was supported by Consejo Nacional de Ciencia y Tecnología (CONACYT grant A1-S-16113 to IEG) and by Secretaría de Investigación y Posgrado, Instituto Politécnico Nacional (IPN). L.V.-F., E.S.P., M.G.-M., and D.B. were recipients of CONACYT fellowships. J.S.-L., R.C.-S., S.E.-P., and I.E.-G. are fellows of Comisión de Operación y Fomento de Actividades Académicas (COFAA)–IPN. J.S.-L., R.C.-S., S.E.-P., I.E.-G., and I.W.-B. are fellows of Estímulos al Desempeño de los Investigadores (EDI)–IPN

Standardized catch rates for Mediterranean swordfish (Xiphias gladius Linnaeus, 1758) from the Spanish longline fishery. 1988-2017.

Standardized relative abundance indices for swordfish (Xiphias gladius Linnaeus, 1758) caught by the Spanish surface longline in the western Mediterranean Sea were estimated for the period 1988-2017. Standardized CPUEs were estimated through a General Linear Mixed Modeling (GLMM) approach under a negative binomial (NB) error distribution assumption. The main factors in the standardization analysis were fishing area and time of the year (quarter). The standardized index showed notable annual fluctuations without any definite trend for the period under study

Fossils in Iberian Prehistory: A Review of the Palaeozoological Evidence.

This paper constitutes the first comprehensive review of animal fossils retrieved in Iberian archaeological sites. Out of 633 items from 82 sites, 143 were analyzed and a further 13 assessed and their status clarified by us on 20 sites. Among others, this study is the first one in Iberia to assess the role played by fossil scaphopods and to carry out a systematic description of shark teeth. The relevance of those 156 fossils we assessed through a comparison with all the finds located in the Iberian literature. Failure to report fossils properly did not allow us to warrant such status for 352 items. We believe that the poor record of fossils in Iberian archaeological sites is the result of a combination of methodological and theoretical constraints. For that reason, we contend that the items herein reported probably represent a fraction, however substantial, of the evidence at hand.UPPH/49/06 aprobado por la Consejería de Cultura de la Junta de Andalucía (España) HAR 2016-77789-P HUM-949 (Universidad de Sevilla), RNM-179 (Universidad de Málaga) ICArEHB (Universidad de Algarve, Portugal