Mechanics of Micro-Architected Lattice Structures

Honeybees construct nests that consist of tessellated hexagonal prismatic structures. The bees develop a linear succession of tetrapod structures that serve as the nest’s foundation in the initial stage of construction. This natural hexagonal lattice structure has been the epitome of extensive aerospace applications. And, has particularly been widely used on aircraft control surfaces as they provide an ideal set of mechanical properties; minimal density and ability to withstand high magnitudes of compressive and shear force. This paper analyses this hexagonal lattice configuration using theoretical analysis and simulations. It first analyses the lattice structure by breaking it down into three individual components somewhat resembling the constructional stages in which the nests are developed: cantilever beam, unit cell which is initially the tetrapod structure, and the complete system of the lattice itself. In further chapters, refined geometries, namely stepped and quadratic lattice of the honeycomb, are then analysed with the objective of enhancing its strength to weight ratio, this is again analysed through the same bottom-up approach and procedure. Two approaches are implemented in the enhancement procedure. The obtained numerical results are then reviewed through simulations using multiple computer-aided software, Solidworks and ANSYS where the mechanical properties are established and compared

Electrical circuit simulation

Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2020, Director: Antoni Benseny[en] Given an electrical circuit, formed by wires, nodes, batteries and resistors, the main goal of this work is to solve this electrical circuit. This means finding the electric current in each wire. The graph theory and its use in computer science through data structures, like trees, and hierarchical traversing algorithms, like the Breadth-first search algorithm, will be used to solve the problem. The first part of the project will intend to solve an electrical circuit using C++, the main algorithms used have been described in this paper. The second part of the project will simulate an electrical circuit using graphics and control libraries allowing to interact with the electrical circuit

Biotechnology applied to aromatic plants for the controlled production of bioactive compounds

Salvia sensu lato includes more than about 9000 species and is considered one of the largest taxa of the Lamiaceae (Will et al., 2015). For a long time, Salvia species were known for a wide variety of medicinal used in folk medicine for the relief of pain, protecting the body against oxidative stress, free radical damages, angiogenesis, inflammation, bacterial and virus infection, etc\u2026 (Hamidpour et al., 2014). In vitro cultures have been considered as an alternative agricultural processes for producing secondary metabolites (Y. Kim et al., 2002). The research activity of this PhD project was aimed to the application of in vitro biotechnology techniques applied to aromatic plants for the production of bioactive compounds. The selected plants are species of Salvia showing an important antibacterial activity. The investigation study was carried out on S. corrugata and S. tingitana. Salvia corrugata Vahl. is an ornamental plant that grown easily along the Mediterranean coast. The aerial part is rich in terpenoid compounds like the diterpene quinones fruticuline A and demethylfruticuline A that present high antibacterial activity. Protocols of tissue culture and genetic transformation were set up with the aim to obtain in vitro shoot and hairy root biomass to grown in controlled condition for metabolite extraction. Two strains of Agrobacterium rhizogenes (wild type ATCC 15834 and hypervirulent LBA9402) were tested for their ability to induce hairy root on wounded leaves. The best response (75 %) was achieved by infection with ATCC 15834 about thirty days after the infection onto the hormone-free MS basal solid medium. Two hairy-root lines from ATCC 15834 treatment and one from LBA 9402 treatment were established. Transformation of selected clones was confirmed by polymerase chain reaction analysis of bacterial rolC and virC1 genes. The growth evaluation in TIS RITA\uae bioreactor put in evidence the best cultural conditions for the biomass production; the clone SCO-HR-FA8 had the best increase on Murashige and Skoog (1962) and \ubd Woody plant medium (Lloyd et al., 1980) salt compositions in comparison to other tested media. 30 mg/L was the best sucrose concentration that guaranteed the highest biomass production. The growth curve of HR lie SCO-HR-FA8 was elaborated and then, three classes of elicitors and their combination were tested: a heavy metal ions (Ag+), the yeast extract and plant response-signaling compound (methyl jasmonate MJ). Among them, Ag+ and yeast extract (YE) at high concentration were most effective to stimulate the biomass production. The scale up of the biomass was performed using the bioreactor RITA\uae. The methanolic extracts of the biomass (16.8 g) was fractionated by Si gel MPLC to obtain 16 fractions. The methanolic extract and the semi-purified fractions were tested against several multidrug resistant clinical strains of various bacterial species: Staphylococci and Enterococci and E. coli. The total extract was poorly effective while the semi purified fractions displayed variable potency with MIC values ranging from 8 to >128 \u3bcg/mL and from 4 to >128 \u3bcg/mL respectively against the Staphylococci and Enterococci strains considered. Our results suggest that the application of biotechnology approach on S. corrugata, it is possible to induce hairy roots from leaf, optimize the condition to increase the production of biomass, scale-up using TIS bioreactor and produce secondary metabolites with antibacterial activity. The study carried out on S. tingitana aimed to develop an in vitro culture protocol to produce different plant tissues and investigate the antibacterial activity of the extract. The callus formation from sterilized leaves was evaluated on MS medium added with different PGRs in presence of ascorbic acid in light or in dark conditions. The result showed the importance of the presence 2,4-D and darkness for callus development. The high development percentage (94.4 %) was achieved by combining KIN and 2,4-D at the concentration of 0.5:0.5 or 1:1 mg/L respectively. The optimization of the medium for the callus growth was determined evaluating the type and concentration of cytokinin and auxin in dark. The suitable condition for callus proliferation was MS medium supplemented with 2,4-D 4.52 \u3bcM, KIN 2,32 \u3bcM and 10 mg /L of ascorbic acid. The elicitation with MJ or light intensity was investigated. The methanolic extract and fractions obtained by MPLC were inactive against Staphylococci species and E. coli. The fractions 11 and 12 displayed an antibacterial activity only against E. faecalis and E. faecium with MIC values ranging from 32 to 64\u3bcg/mL. In S. tingitana, a successful protocol for callus production was established; this in vitro culture system can be used as good method to obtain medicinally-useful secondary compounds from S. tingitana

El fútbol femenino profesional. Una perspectiva de género desde argentina, costa rica y México

La presente investigación se desarrolla bajo la perspectiva teórica que ofrece el feminismo de la diferencia sexual, que surge en la década de los setentas, deshaciendo la idea de naturalizar el cuerpo bajo un sistema de género opresivo, argumentando que el hecho de tener cuerpo de mujer no tiene por qué ser motivo para identificarse con el género femenino, en palabras de Montserrat Martín (2006.10) “el objetivo de estas feministas era demostrar que las mujeres no estaban naturalmente impedidas para representar el género masculino, y se imaginaron que poder acceder a este género desde un cuerpo de mujer era lograr la igualdad con los hombres” por lo que consideramos que dentro de nuestra realidad estudiada, como en otros espacios, es necesario reivindicar el papel de las mujeres en tanto son capaces de desarrollar diversas tareas que simbólicamente están constituidas como masculinas, sin que por esa razón pierdan su identidad como féminas. Por lo que vincularemos esta propuesta teórica al tema del deporte, específicamente sobre el papel que están desarrollando las mujeres en la práctica profesional del fútbol. El problema que se inscribe en nuestro trabajo resulta del impacto que origina la entrada de las mujeres al mundo futbolístico, espacio tradicionalmente reivindicado por el sexo masculino, en el que históricamente el orden patriarcal ha operado desde un conjunto de habitus sociales, en los que la dominación masculina se ejerce, legitima y reproduce para exaltar el poder simbólico del denominado “sexo fuerte” (Archetti, 1985). Esta investigación pretende realizar un análisis sobre la construcción de identidades y la búsqueda de nuevos espacios de acción de las mujeres en el deporte, reflexionando sobre el papel de las jugadoras como actoras jóvenes, quienes buscan construir un espacio propio que les identifique. Para ello, las bases teóricas que sustentan este trabajo, serán las formuladas por la corriente teórica del feminismo de la diferencia, la cual pugna por el reconocimiento de las diferencias biológicas entre hombres y mujeres, mientras que critica las diferencias simbólicas que se han construido históricamente con base en la sexualidad, que se hace evidente con la asignación desigual de tareas y roles sociales.La presente investigación se desarrolla bajo la perspectiva teórica que ofrece el feminismo de la diferencia sexual, que surge en la década de los setentas, deshaciendo la idea de naturalizar el cuerpo bajo un sistema de género opresivo, argumentando que el hecho de tener cuerpo de mujer no tiene por qué ser motivo para identificarse con el género femenino, en palabras de Montserrat Martín (2006.10) “el objetivo de estas feministas era demostrar que las mujeres no estaban naturalmente impedidas para representar el género masculino, y se imaginaron que poder acceder a este género desde un cuerpo de mujer era lograr la igualdad con los hombres” por lo que consideramos que dentro de nuestra realidad estudiada, como en otros espacios, es necesario reivindicar el papel de las mujeres en tanto son capaces de desarrollar diversas tareas que simbólicamente están constituidas como masculinas, sin que por esa razón pierdan su identidad como féminas. Por lo que vincularemos esta propuesta teórica al tema del deporte, específicamente sobre el papel que están desarrollando las mujeres en la práctica profesional del fútbol

The Language of Entry-Level Job Interviews

The need for data-based studies of language use extends throughout the field of ESP. Such studies are needed to assess learners' needs with any degree of accuracy. In response to this need for data-based studies of language use, a study was undertaken to gather information on entry-level job interview for the design of Vocational ESL materials. Eight entry-level interviews were recorded, transcribed and analyzed. Two NS interviewers at different job sites participated in the study; each interviewer interviewed two NSs and two NNSs. The transcribed interviews were analyzed to identify discourse features such as topics, lexical items and certain syntactic structures, as well as to determine the frequencies of these features. The structure of entry-level job interviews was determined, based on both the entry-level interview data and a surveryof related literature. A literature survey also provided information on the conventions that have been established for interaction in job interviews. Finally, the communicative behhaviors of the applicats were examined in light of this information, in order to ascertain the particular needs of the target group.The need for data-based studies of language use extends throughout the field of ESP. Such studies are needed to assess learners' needs with any degree of accuracy. In response to this need for data-based studies of language use, a study was undertaken to gather information on entry-level job interview for the design of Vocational ESL materials. Eight entry-level interviews were recorded, transcribed and analyzed. Two NS interviewers at different job sites participated in the study; each interviewer interviewed two NSs and two NNSs. The transcribed interviews were analyzed to identify discourse features such as topics, lexical items and certain syntactic structures, as well as to determine the frequencies of these features. The structure of entry-level job interviews was determined, based on both the entry-level interview data and a surveryof related literature. A literature survey also provided information on the conventions that have been established for interaction in job interviews. Finally, the communicative behhaviors of the applicats were examined in light of this information, in order to ascertain the particular needs of the target group

Esportes e atletas em tempos de pandemia: Desigualdades de gênero sob a «nova normalidade»

The global contingency produced by COVID-19 has disrupted the different spaces, sectors and economic, political and social activities; sport is no exception. Since the suspension of competitions and massive events; the transmission of «new» media content; the postponement of the Olympic games; even the readaptation of spaces and training routines by athletes, have been some of the changes that have arisen in an emergent way. Although we are facing a global phenomenon, it is important to consider that the effects for men and women have not been the same. In the Mexican case, the effects of the pandemic on female athletes were reflected in the uncertainty about maintaining their salaries; the lack of resources for their training and in the restriction of spaces and sports facilities. In addition to all this, in the domestic setting, they have concatenated sports activities with household chores and caring for others. Such a situation invites us to reflect on the structural inequalities in sports in terms of gender, as well as the social configuration of the space (public and private) and its sexual division. Starting from this context, we ask ourselves, what were the changes that the athletes faced from the isolation and restriction of the use of courts, gyms, lounges and training fields? How did the pandemic modify the ways of life and the sports training of women? How do female athletes turn the domestic space into a space of resistance? How was confinement able to affect female athletes than men in a different way? To respond to these questions, the text aims to analyze the effects of confinement and the «new normal» in the practice of sport from a gender perspective, to identify the relations of power, subjectivation and inequality, evidenced by the pandemic. As an empirical contribution, the testimonies of athletes from disciplines such as soccer and sports shooting are rescued, as well as representatives of the mass media and sports specialists.La contingencia global producida por la COVID-19 ha trastocado los diferentes espacios, sectores y actividades económicas, políticas y sociales; el deporte no es la excepción. Desde la suspensión de las competencias y eventos masivos; la transmisión de «nuevos» contenidos mediáticos; el aplazamiento de los juegos olímpicos; hasta la readaptación de espacios y rutinas de entrenamiento por parte de los y las deportistas, han sido algunos de los cambios que se han suscitado de forma emergente./nA pesar de que estamos ante un fenómeno mundial, es importante considerar que las afectaciones para hombres y para mujeres no han sido las mismas. En el caso mexicano, los efectos de la pandemia en deportistas mujeres se reflejaron en la incertidumbre sobre el mantenimiento de sus salarios; la falta de recursos para su entrenamiento y en la restricción de espacios e instalaciones deportivas. Aunado a todo ello, en el escenario doméstico, estas han concatenado las actividades deportivas con tareas del hogar y el cuidado de los otros. Tal situación nos invita a reflexionar sobre las desigualdades estructurales en los deportes en términos de género, así como la configuración social del espacio (público y privado) y la división sexual del mismo./nPartiendo de este contexto nos preguntamos ¿cuáles fueron los cambios a los que las deportistas se enfrentaron a partir del aislamiento y la restricción del uso de canchas, gimnasios, piscinas, salones y campos de entrenamiento?, ¿cómo la pandemia modificó las formas de vida y la formación deportiva de las mujeres?, ¿cómo las mujeres deportistas hacen del espacio doméstico un espacio de resistencia?, ¿cómo el confinamiento pudo afactar de forma diferenciada a deportistas mujeres que a hombres? Para dar respuesta a estos cuestionamientos, el texto pretende analizar los efectos del confinamiento y de la «nueva normalidad» en la práctica del deporte desde la perspectiva de género, para identificar las relaciones de poder, subjetivación y desigualdad evidenciadas por la pandemia. Como aporte empírico se rescatan los testimonios de deportistas de disciplinas como fútbol y tiro deportivo, así como de representantes de los medios masivos de comunicación y especialistas en deporte.A contingência global produzida pela COVID-19 tem desorganizado os diferentes espaços, setores e atividades econômicas, políticas e sociais; o esporte não é exceção. Desde a suspensão de competições e eventos massivos; a transmissão de «novos»conteúdos de mídia; o adiamento dos jogos olímpicos; até a readaptação de espaços e rotinas de treinamento pelos atletas, têm sido algumas das mudanças que surgiram de forma emergente. Embora estejamos diante de um fenômeno global, é importante considerar que os efeitos para homens e mulheres não foram os mesmos. No caso mexicano, os efeitos da pandemia nas atletas se refletiram na incerteza quanto à manutenção de seus salários; a falta de recursos para a sua formação e a restrição de espaços e instalações desportivas. Além de tudo isso, no ambiente doméstico, concatenam as atividades esportivas com as tarefas domésticas e o cuidado do outro. Essa situação nos convida a refletir sobre as desigualdades estruturais do esporte em termos de gênero, bem como a configuração social do espaço (público e privado) e sua divisão sexual. Partindo desse contexto, nos perguntamos: quais foram as mudanças que os atletas enfrentaram com o isolamento e a restrição do uso de quadras, academias, salões e campos de treinamento? Como a pandemia modificou os modos de vida e a formação esportiva dos mulheres? Como as atletas femininas tornam o espaço doméstico um espaço de resistência? Como o confinamento foi capaz de afetar as atletas femininas e os homens de forma diferente? Para responder a essas questões, o texto tem como objetivo analisar os efeitos do confinamento e do «novo normal» na prática esportiva a partir de uma perspectiva de gênero, para identificar as relações de poder, subjetivação e desigualdade, evidenciadas pela pandemia. Como contribuição empírica, são resgatados depoimentos de atletas de modalidades como futebol e tiro esportivo, representantes de meios de comunicação e especialistas em esportes

Arago (1810): the first experimental result against the ether

95 years before Special Relativity was born, Arago attempted to detect the absolute motion of the Earth by measuring the deflection of starlight passing through a prism fixed to the Earth. The null result of this experiment gave rise to the Fresnel's hypothesis of an ether partly dragged by a moving substance. In the context of Einstein's Relativity, the sole frame which is privileged in Arago's experiment is the proper frame of the prism, and the null result only says that Snell's law is valid in that frame. We revisit the history of this premature first evidence against the ether theory and calculate the Fresnel's dragging coefficient by applying the Huygens' construction in the frame of the prism. We expose the dissimilar treatment received by the ray and the wave front as an unavoidable consequence of the classical notions of space and time.Comment: 16 pages. To appear in European Journal of Physic

Contribution of catastrophic events to stochasticity of the recruitment process: an application to Atlantic salmon

RésuméInternational audienc

Interference with polarized light beams: Generation of spatially varying polarization

Using a scheme based on a Mach-Zehnder interferometer, we propose an analysis of the superposition of polarized laser beams at a given angle. The focus of our study is the spatially varying polarization state of the resulting field, also known as a polarization grating, generated by this setup. Our proposal combines a theoretical description of the resulting field in terms of its Stokes parameters with an experimental demonstration of the existence of such a polarization grating due to the effects of polarization on beam interference experiments.Comment: 16 pages, 9 figure