Designing optimal controls by parameter optimization for a stance-control knee-ankle-foot orthosis

Inverse dynamics simulation is often used in robotic and mechatronic systems to track a desired trajectory by feed-forward control. Musculoskeletal multibody systems are highly overactuated and show a switching number of closed kinematical loops. The method of inverse dynamics is also successfully applied to overactuated systems by parameter optimization for two- and three-dimensional models of the human musculoskeletal system. The presented simulation approach is fully based on optimizationPostprint (published version

Bases para el relevo generacional de las directivas de Comercial y Servicios Larco S. A.

La presente investigación, de tipo exploratorio, da cuenta de la revisión de los procedimientos, las responsabilidades y el perfil del cargo de Gerente Técnico Financiero de la empresa Comercial y Servicios Larco S. A., con el fin de plantear los principios que faciliten la implementación de protocolos de transferencia de conocimiento en el cargo definido, para garantizar la sucesión generacional, sin pérdida de conocimiento -- Para ello se propone trabajar el cargo mediante el análisis de documentos y de una entrevista en profundidad al directivo que actualmente ocupa el cargo definid

SOCIAL TRANSFORMATION DURING THE MIDDLE - LATE PRECLASSIC (1,000 BCE - 150 BCE) AT UCÍ, YUCATAN MEXICO

The focus of this project is to track the social change developments in Ucí, Yucatan, Mexico, during the Middle (1,000 – 400 BCE) and Late Preclassic (400 – 150 BCE) that served as foundations to institutionalized hierarchy. This research is geared towards understanding if there were any expressions of social differentiation in the earliest, detectable moments in the history of Ucí, and what were the mechanisms used to eventually make distinctions permanent. Applying an agency approach, I argue that social actors may cause structural change, both consciously and inadvertently, through the application of several strategies aimed to enhancing their role and status within their society. I make use of data from extensive mapping, test excavations, and broad, horizontal excavations at two specific structures to assess differential access to labor, resources, and sumptuary materials. Results show that there was a noticeable change between the Middle and Late Preclassic with regards to labor practices, in which communal institutions were appropriated by individuals or families to enhance their status. Test and broad excavations demonstrated that there was a shift in focus in labor practices from a central structure to outlying, multiple structures. The artifact assemblages at these later structures show that these were most likely used as centers for congregation. The groups here represented used a series of strategies to gain socio-political followers such as rituals, music performances, and the consumption of food and beverages. I believe that this would have ultimately threatened a sense of community. In the Late Preclassic we see the creation of a ceremonial circuit that links the outlying structures to the center of the site through a network of causeways. I believe that this created to diminish social fractures and enhance a sense of community. In this configuration it seems likely that the various interest groups, represented by the outlying structures, could have entered into a competition to host community-wide rituals and enhance institutionalized forms of social differentiation

Role and functions of Pitx2 regulating satellite cell biology

El proceso de regeneración muscular es llevado a cabo por las células madre musculares, llamadas células satélite. En este trabajo, vemos cómo el factor de transcripción Pitx2, que tiene un papel importante en morfogénesis muscular, es necesario para una correcta diferenciación celular. En experimentos in vitro de ganancia de función de Pitx2 hemos visto como se produce un incremento de la diferenciación de las células musculares mientras que en pérdida de función de Pitx2 conduce a una diferenciación alterada e incompleta. Además, hemos puesto de manifiesto que las células distróficas aisladas de ratones mdx muestran la diferenciación miogénica defectuosa asociada con una expresión disminuida de Pitx2. Pitx2 aumenta el número de fibras musculares, llegando a la restauración parcial de la distrofina y, finalmente, mejora la función muscular en ratones mdx. Estos resultados ponen a Pitx2 como un nuevo participante en la biología de las células satélite musculares identificándose funciones desconocidas de Pitx2 durante la miogénesis regenerativa.The process of muscle regeneration is accomplished by the muscle stem cells, called satellite cells. In this investigation, Pitx2, which is a transcription factors, has an important role in morphogenesis, is necessary for a correct cell differentiation. In in vitro experiments of acquire of function of Pitx2 we have seen an increase in the differentiation of muscle cells, while in loss of function of Pitx2 leads to an altered and incomplete differentiation. In addition, we have revealed that dystrophic cells isolated from mdx mice show the defective myogenic differentiation associated with a decreased expression of Pitx2. Pitx2 increases the number of muscle fibers, reaching the partial restoration of dystrophin and, finally, it improves muscle function in mdx mice. These results place Pitx2 as a new participant in the biology of muscle satellite cells, identifying unknown functions of Pitx2 during regenerative myogenesis.Tesis Univ. Jaén. Departamento de Biología Experimental. Leída el 6 de marzo de 2018

Dreams of Molecular Beams: Indium Gallium Arsenide Tensile-Strained Quantum Dots and Advances Towards Dynamic Quantum Dots (Moleculare Radiorum Somnia: Indii Gallii Arsenicus Tensa Quanta Puncta et ad Dinamicae Quantae Puntae Progressus)

Through the operation of a molecular beam epitaxy (MBE) machine, I worked on developing the homoepitaxy of high quality InAs with a (111)A crystallographic orientation. By tuning substrate temperature, we obtained a transition from a 2D island growth mode to step- ow growth. Optimized MBE parameters (substrate temperature = 500 °C, growth rate = 0.12 ML/s and V/III ratio ⩾ 40) lead to growth of extremely smooth InAs(111)A films, free from hillocks and other 3D surface imperfections. We see a correlation between InAs surface smoothness and optical quality, as measured by photoluminescence spectroscopy. This work establishes InAs(111)A as a platform for future research into other materials from the 6.1 Å family of semiconductors grown with a (111) orientation. Continuing this work, we also have determined a reproducible set of growth conditions for the self-assembly of tensile-strained In1-xGaxAs quantum dot nanostructures on InAs(111)A surfaces. During molecular beam epitaxy, In1-xGaxAs islands form spontaneously on InAs(111)A when the Ga content x ≥ 50 %. We analyze the structure and composition of InGaAs/InAs(111) samples using atomic force microscopy, transmission electron microscopy, electron energy loss spectroscopy, and photoluminescence spectroscopy. We demonstrate control over the size and areal density of the islands as a function of In1-xGaxAs coverage, In1-xGaxAs composition, and substrate temperature. Furthermore, we also present a study aimed to determining the growth conditions of In1-xGaxAs self-assembled tensile-strained QDs on GaSb(111)A surfaces. From previous work we determined that a larger band gap barrier was necessary to ensure the confinement of charge carriers in the InGaAs nanostructures. Through a series of temperature, V/III ratio, and growth rate we determined the best parameters for GaSb(111) homoepitaxy. We then studied the nucleation of optimal-morphology In1-xGaxAsQDs by locking the compositions at In0.5Ga0.5As, studying the critical pause for group V element transition and V/III ratio prior and post QD growth. Several photoluminescence techniques are employed to determine the light emission properties of these structures. Finally, we did preliminary studies on how to achieve the dynamic lateral confinement of charge carriers in 2D and 3D using near-THz surface acoustic phonon pulses in polar semiconductors. Using the acousto-electrical effect, we measure the degree to which surface acoustic waves (SAWs) confine electrons and holes limiting the number of recombination processes. Applications for this technological development include the external modulation of lateral confinement size in the SAWs and subsequent photon emission wavelength, as well as potential quantum logical gate design using acoustic pulses to drive electrons in a circuit

Coordination compounds of organosulfur ligands as precursors of nanostructured materials.

354 p.This work presents the synthesis and characterization of a series of coordination compounds based on metal(II)-organosulfur complexes as precursors of zero- and three-dimensional nanomaterials.On the one hand, thiocarboxylato ligands have been used for the preparation of metal(II) sulfide nanoparticles both in pure form and as homogeneous dispersion within a carbonaceous matrix. Dry thermolysis, the synthetic method chosen to achieve this goal, is a simple, controllable and economical route that allows the scaling of these materials, a requirement that the industrial sector demands.Moreover, 3D nanoporous structures have been obtained by gelation of coordination polymers based on dithioxamidato ligand. The entrapped solvent can be extracted from the gels through a supercritical treatment, consolidating the structure in the form of aerogels: ultralight mesoporous solids in which more than 80% of their volume is made up of air. Throughout the text the reader will have the opportunity to discover the surprising physicochemical properties exhibited by this emerging class of metal-organic materials

Detection of Communities within the Multibody System Dynamics Network and Analysis of Their Relations

Multibody system dynamics is already a well developed branch of theoretical, computational and applied mechanics. Thousands of documents can be found in any of the well-known scientific databases. In this work it is demonstrated that multibody system dynamics is built of many thematic communities. Using the Elsevier’s abstract and citation database SCOPUS, a massive amount of data is collected and analyzed with the use of the open source visualization tool Gephi. The information is represented as a large set of nodes with connections to study their graphical distribution and explore geometry and symmetries. A randomized radial symmetry is found in the graphical representation of the collected information. Furthermore, the concept of modularity is used to demonstrate that community structures are present in the field of multibody system dynamics. In particular, twenty-four different thematic communities have been identified. The scientific production of each community is analyzed, which allows to predict its growing rate in the next years. The journals and conference proceedings mainly used by the authors belonging to the community as well as the cooperation between them by country are also analyzed

Creativity applied to architectural design

En arquitectura el término de creatividad se ciñe, en muchas ocasiones, al producto final presentado, en calidad de objeto innovador, como resultado de un proceso creativo y metodológico previo. Sin embargo, las perspectivas académicas están ampliándose y reconocen la importancia de consolidar factores que intervienen en la construcción de la creatividad, tales como el contexto universitario y la motivación cognitiva, entre otros. A fin de favorecer el desarrollo creativo dentro del proceso de diseño, y potencializar el conocimiento adquirido en los estudiantes de Arquitectura, de la Facultad de Estudios Superiores Aragón de la Universidad Nacional Autónoma de México. El presente trabajo evalúa la capacidad creativa de los alumnos respecto a la motivación, afectividad y cognición, esto mediante la aplicación de modelos basados en sistemas clasificatorio, algorítmico, heurístico y cognitivo, valorando la existencia de correlación con el rendimiento académico a través de pruebas de hipótesis entre grupos de alumnos de Arquitectura por grado cursado, edad y género. Este estudio considera, que una vez evaluadas y detectadas las habilidades dispuestas en los alumnos, mejorará las posibilidades de estrategias aplicables al proceso del diseño arquitectónico, encausadas a la óptima y libre acciónIn architecture the term of creativity is limited, on many occasions, to the final product presented, in quality of innovative object, as a result of a previous creative and methodological process. However, the academic prospects are expanding and recognize the importance of strengthening factors that go into the construction of creativity such as the University context and cognitive motivation, among others. In order to facilitate the creative development within the design process. And potentialize the knowledge acquired on the students of program of study of architecture of Aragón study superior faculty (FES) Aragon, about of Mexico National University (UNAM). This project It evaluates the creative capacity of students with respect to motivation, emotion and cognition, this through the application of models based on system classification, algorithmic, heuristic and cognitive, assessing the existence of a correlation with the academic performance through hypothesis testing between groups of students of architecture by completed level, age and gender. This study considers that once assessed and detected the skills arranged in the students, Will improve the possibilities of strategies applicable to the process of architectural design, aimed at optimum and free actio