Identification and geomorphic characterization of fluvial knickzones in bedrock rivers from Courel Mountains Geopark

The gradient characteristics of Courel Mountains Geopark bedrock rivers were examined. Unlike alluvial rivers, bedrock rivers have been the great forgotten of fluvial geomorphology globally. Based on the decreasing rate of gradient with increasing measurement length, a relative steepness was obtained as indicator of knickzone. Supported by GIS techniques and DEMs, the changes in slope along the longitudinal profile of the rivers were detected. The number of the extracted knickzones rises to 325, which means a frequency of knickzones of 0.467 km−1. The total length of the knickzones is 285 km, representing about half of the drainage network as knickzone (47%). The mean height, the length, and the gradient of all the knickzones were ~ 110 m, ~ 880 m, and 0.178 m·m−1, respectively. There is no distribution pattern and the knickzones are everywhere, although they are more present in reaches with NW–SE direction and order 1. Several environmental factors were crossed to know more about the occurrence and knickzones characteristics, suggesting that density and direction of fractures regulate the number and the trajectory of the knickzones, while the lithology controls the singularity of the forms. The geomorphological and the topographical characteristics of the bedrock rivers make them high ecological, scenic, landscape, and recreational value. Findings from this study can be also used by managers to develop and/or improve strategies for conservation, valorisation, and how to approach the tourist who visits the Geopark. Scientific tourism can offer a unique and educational travel experience, allowing participants to learn about bedrock rivers and knickzonesOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer NatureS

Leaf regrowth stage as a morpho-physiological indicator of Bromus valdivianus and Lolium perenne mixed pasture defoliation in New Zealand grazing system : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Manawatū, New Zealand

Bromus valdivianus Phill. is a perennial grass species native to the South of Chile. Its better fitness for growing under low water availabilities compared with Lolium perenne L. has been assessed in field and glasshouse studies. However, Bromus valdivianus morpho-physiological attributes, such as root development under field conditions, and competitive ability are likely to manifest differently under contrasting defoliation criteria based on leaf regrowth stage. In addition, Lolium perenne and B. valdivianus growth can be complementary throughout the year under rainfed conditions. Therefore, the objective of the present thesis was to determine defoliation criteria based on leaf regrowth stage of mixed pastures (50/50% L. perenne and B. valdivianus) and consequences for species succession and functional traits development of the species. Four studies were developed in the thesis, two glasshouse and two field studies. The first glasshouse study evaluated the growth response and water-soluble carbohydrate (WSC) accumulation of B. valdivianus at three different defoliation frequencies. The results suggested that B. valdivianus increased herbage mass production and root biomass at low defoliation frequency (i.e., at 3.5–4.0 leaf regrowth stage). This was related to a higher WSC accumulation in the tiller base. In addition, under low soil water availabilities (20–25% of field capacity) WSC increased by ~20%, which indicated a drought resistant strategy of this species. The second study proved the growth enhancement (mainly root length and biomass) of B. valdivianus under competition with L. perenne compared with intraspecific competition when soil water shifted from high to low availabilities. In field studies, B. valdivianus mixed with L. perenne increased ~15% accumulated herbage mass compared to the species monocultures, which supported higher production during dry periods. This was due to the niche complementarity and asynchrony in herbage growth between the species, with B. valdivianus capable to maintain a steady tiller population throughout the year and root biomass accumulation at depth. Whereas L. perenne grew more than B. valdivianus under low level of oxygen in the soil and under optimal growth conditions and presented a higher nutritive value than B. valdivianus during winter, spring and autumn. The latter supports the partial grazing preference for L. perenne shown by sheep during part of the year, as measured in the second field study. This lower nutritive value (less energy) of B. valdivianus monocultures was overcame in the mixture, with a good overall value for high animal production. Regarding the mixture defoliation criterion, it was shown that it can be based on the optimal leaf regrowth stage of either species, as herbage mass production was similar between defoliation frequencies based on optimal leaf regrowth stage of either of the species. However, under defoliation based on optimal leaf regrowth stage of B. valdivianus, root biomass accumulation at depth increased ~45%. Overall, the results of the present thesis evidenced that Bromus valdivianus can successfully grow alongside L. perenne and, therefore, the mixture can increase forage production of New Zealand farming system in the event of climate change

Multiscale computational homogenization: review and proposal of a new enhanced-first-order method

This is a copy of the author 's final draft version of an article published in the Archives of computational methods in engineering. The final publication is available at Springer via http://dx.doi.org/10.1007/s11831-016-9205-0The continuous increase of computational capacity has encouraged the extensive use of multiscale techniques to simulate the material behaviour on several fields of knowledge. In solid mechanics, the multiscale approaches which consider the macro-scale deformation gradient to obtain the homogenized material behaviour from the micro-scale are called first-order computational homogenization. Following this idea, the second-order FE2 methods incorporate high-order gradients to improve the simulation accuracy. However, to capture the full advantages of these high-order framework the classical boundary value problem (BVP) at the macro-scale must be upgraded to high-order level, which complicates their numerical solution. With the purpose of obtaining the best of both methods i.e. first-order and second-order, in this work an enhanced-first-order computational homogenization is presented. The proposed approach preserves a classical BVP at the macro-scale level but taking into account the high-order gradient of the macro-scale in the micro-scale solution. The developed numerical examples show how the proposed method obtains the expected stress distribution at the micro-scale for states of structural bending loads. Nevertheless, the macro-scale results achieved are the same than the ones obtained with a first-order framework because both approaches share the same macro-scale BVP.Peer ReviewedPostprint (author's final draft

Peak forces and lateral resolution in amplitude modulation force microscopy in liquid

This is an Open Access article under the terms of the Creative Commons Attribution License.The peak forces exerted on soft and rigid samples by a force microscope have been modeled by performing numerical simulations of the tip motion in liquid. The forces are obtained by using two contact mechanics models, Hertz and Tatara. We present a comparison between the numerical simulations and three analytical models for a wide variety of probe and operational parameters. In general, the forces derived from analytical expressions are not in good quantitative agreement with the simulations when the Young modulus and the set-point amplitude are varied. The only exception is the parametrized approximation that matches the results given by Hertz contact mechanics for soft materials and small free amplitudes. We also study the elastic deformation of the sample as a function of the imaging conditions for materials with a Young modulus between 25 MPa and 2 GPa. High lateral resolution images are predicted by using both small free amplitudes (less than 2 nm for soft materials) and high set-point amplitudes. © 2013 Guzman and Garcia.This work was funded by the Ministerio de Economía y Competitividad (Consolider Force-For-Future, CSD2010-00024, MAT2009-08650) and European Union Seventh Framework Programme [FP7/2007-2013] under grant agreement no. 280772, project iONE-FP7 and the Cost Action TD1002.Peer Reviewe

Feeding Behavior of Spurilla sp. (Mollusca: Opisthobranchia) with a Description of the Kleptocnidae Sequestered from Its Sea Anemone Prey

Feeding behavior of Spurilla sp. (Mollusca: Opisthobranchia) with a description of the kleptocnidae sequestered from its sea anemone prey. Zoological Studies 51(7): 905-912. Cnidocysts are sequestered from cnidarian prey by aeolid nudibranchs and stored in the tips of their appendages (cerata). The kleptocnidae of 11 specimens of Spurilla sp. are described in detail. The types and relative abundances of prey cnidocysts in nudibranch cerata were highly variable, suggesting exclusive anemone consumption. Spirocysts and several types of microbasic p-mastigophores, microbasic b-mastigophores, and basitrichs were found in external and internal tissues of sea anemone prey. This is the 1st report of predation of aeolid Spurilla sp. on the sea anemones Antholoba achates, Metridium senile lobatum, and Parabunodactis imperfecta from the rocky intertidal of Patagonia (Chubut Province, Argentina) and on Anthothoe chilensis and Tricnidactis errans at Mar del Plata (Buenos Aires Province, Argentina). Photographs and digital videos of aeolidacean feeding behavior were recorded in situ and in aquaria. The purpose of this study was to provide valuable information on the diet of Spurilla sp. from Argentina using field observations and descriptions of the kleptocnidae.Fil: Garese, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: García Matucheski, Stella. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; ArgentinaFil: Muniain, Claudia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Acuña, Fabian Horacio. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Identidades juveniles en escenarios de periferización urbana. Una aproximación biográfica

In this paper we focus on identity processes to analyze a series of narrations produced through a biographical approach. These narrations belong to youngsters who live in popular areas of the city of Córdoba. Our analysis support certain propositions stated by other researches pointing at neighborhoods as identity operators and at the street as a dangerous place. Nevertheless we observe that the definition of the residence as ‘barrio’ or ‘villa’ implies for youngsters an active symbolic dispute, showing that stigmatization processes are not exclusive of experiences taking place out of the neighborhood. Throughout this paper we give account for some discursive, moral and emotional operations through which youngsters get to present themselves as members of “respectful” neighborhoods, stating an identity distance with certain threatening othernesses wondering around ‘the street’: physic and symbolic place that appears to be an obstacle for their projections to institution-based “subworlds” such as school and work.En esta comunicación analizamos en clave identitaria una serie de narrativas de jóvenes cordobeses de sectores populares construidas a partir de un enfoque biográfico. Nuestro análisis abona ciertas proposiciones que desde otras investigaciones señalan al barrio como operador de identidad y cohesión y a la calle como lugar peligroso. Sin embargo, observamos también que para los jóvenes la definición de su lugar de residencia como ‘barrio’ o ‘villa’ supone una activa disputa simbólica, con lo cual los procesos de estigmatización no serían exclusivos del “afuera barrial”. A lo largo del trabajo damos cuenta de algunas operaciones discursivas, morales y emocionales mediante las cuales los jóvenes consiguen presentarse como integrantes de barrios “respetables”, marcando una distancia identitaria con ciertas alteridades amenazantes que pueblan el mundo de ‘la calle’: espacio físico y simbólico que parecería constituir un desafío para la proyección juvenil hacia ciertos “submundos” institucionales como el trabajo y la escuela

Analysis of ultra low cycle fatigue problems with the barcelona plastic damage model

This paper presents a plastic formulation based on the Barcelona plastic damage model ([1], [2]) capable of predicting the material failure due to Ultra Low Cycle Fatigue. This is achieved taking into account the fracture energy dissipated during the cyclic process. This approach allows the simulation of ULCF in regular cyclic tests, but also in non-regular cases such as seismic loads

El filtro afectivo y el nivel de logro en la habilidad de “speaking” en los estudiantes de la carrera de idiomas - especialidad inglés de la Escuela de Educación Superior Pedagógica Pública “Indoamérica” – Trujillo

La presente investigación tuvo como propósito determinar la relación que existe entre el filtro afectivo y el nivel de logro en la habilidad de “speaking” en los estudiantes de la carrera de idiomas - especialidad inglés de la Escuela de Educación Superior Pedagógica Pública “Indoamérica” - Trujillo. La muestra estuvo conformada por todos los estudiantes de la carrera de idiomas – especialidad inglés de la Escuela de Educación Superior Pedagógica Pública “Indoamérica” - Trujillo. Asimismo, el diseño de investigación empleado fue de tipo descriptivo – correlacional y los instrumentos que permitieron la recolección de la información necesaria para este trabajo fueron el cuestionario para medir al filtro afectivo de los estudiantes participantes de este estudio y la rúbrica de evaluación para recopilar la calificación alcanzada en la evaluación de la habilidad de “speaking” por tales estudiantes. Se demostró en los resultados obtenidos que existe una relación altamente significativa (p < 0.01) y a la vez inversa entre el filtro afectivo y el nivel de logro en la habilidad de “speaking” en los estudiantes de la carrera de idiomas - especialidad inglés de la Escuela de Educación Superior Pedagógica Pública “Indoamérica” - TrujilloThe purpose of this research was to determine the relationship between the affective filter and achievement level in speaking skill of the students from the language career - English specialty of Escuela de Educación Superior Pedagógica Pública “Indoamérica”. The sample consisted of all the students of the language career from “Indoamerica”. Moreover, the research design was descriptive - correlational and the instruments used were the survey which helped to score the affective filter of the students and the speaking rubric which collected the grades that students achieved in such skill. It was demonstrated by the results that there is a highly significant and inverse relationship between the affective filter and achievement level in speaking skill of the students from the language career - English specialty of Escuela de Educación Superior Pedagógica Pública “Indoamérica”.Tesi

Multiscale thermo-mechanical analysis of multi-layered coatings in solar thermal applications

Solar selective coatings can be multi-layered materials that optimize the solar absorption while reducing thermal radiation losses, granting the material long-term stability. These layers are deposited on structural materials (e.g., stainless steel, Inconel) in order to enhance the optical and thermal properties of the heat transfer system. However, interesting questions regarding their mechanical stability arise when operating at high temperatures. In this work, a full thermo-mechanical multiscale methodology is presented, covering the nano-, micro-, and macroscopic scales. In such methodology, fundamental material properties are determined by means of molecular dynamics simulations that are consequently implemented at the microstructural level by means of finite element analyses. On the other hand, the macroscale problem is solved while taking into account the effect of the microstructure via thermo-mechanical homogenization on a representative volume element (RVE). The methodology presented herein has been successfully implemented in a reference problem in concentrating solar power plants, namely the characterization of a carbon-based nanocomposite and the obtained results are in agreement with the expected theoretical values, demonstrating that it is now possible to apply successfully the concepts behind Integrated Computational Materials Engineering to design new coatings for complex realistic thermo-mechanical applications.Peer ReviewedPostprint (author's final draft