Portfolio of compositions

This portfolio comprises the nine pieces written during my PhD research at the University of York and a commentary about the process of composition. My work seeks to focus on timbre and texture as guiding parameters, with due attention to comprehensibility through unity of material. I first give an overview of my compositional processes during the years previous to my research. Then I discuss the general principles of my present approach, sketching the links between it and earlier work. Finally, I illustrate these principles by discussing individual pieces and the links between them

Padrões de acúmulo de proteínas e carboidratos durante a embriogênese somática de Acca sellowiana

The aim of this work was to quantify the protein, starch and total sugars levels during histodifferentiation and development of somatic embryos of Acca sellowiana Berg. For histological observations, the samples were dehydrated in a battery of ethanol, embedded in historesin and stained with toluidine blue (morphology), coomassie blue (protein bodies) and periodic acid-Schiff (starch). Proteins were extracted using a buffer solution, precipitated using ethanol and quantified using the Bradford reagent. Total sugars were extracted using a methanol-chloroform-water (12:5:3) solution and quantified by a reaction with anthrone at 0.2%. Starch was extracted using a 30% perchloric acid solution and quantified by a reaction with anthrone at 0.2%. During the somatic embryogenesis' in vitro morphogenesis and differentiation processes, the total protein levels decreased and the soluble sugars levels increased during the first 30 days in culture and remained stable until the 120th day. On the other hand, total protein levels increased according to the progression in the developmental stages of the somatic embryos. The levels of total sugars and starch increased in the heart and cotyledonary stages, and decreased in the torpedo and pre-cotyledonary stages. These compounds play a central role in the development of somatic embryos of Acca sellowiana. © 2009 Embrapa Informação Tecnológica.O objetivo deste trabalho foi quantificar os teores de proteína, amido e açúcares totais durante a histodiferenciação e desenvolvimento dos embriões somáticos em Acca sellowiana Berg. Para as observações histológicas, as amostras foram desidratadas em uma bateria de etanol, emblocadas em historesina e coradas com azul de toluidina (morfologia), azul de coomassie (corpos proteicos) e reativo ácido periódico de Schiff (amido). As proteínas foram extraídas usando uma solução tampão, precipitadas usando etanol e quantificadas por meio do reativo de Bradford. Os açúcares totais foram extraídos usando uma solução metanol-clorofórmioágua (12:5:3) e quantificados pela reação com antrona a 0,2%. O amido foi extraído usando uma solução de ácido perclórico a 30% e quantificado pela reação com antrona a 0,2%. Durante a diferenciação e morfogênese in vitro da embriogênese somática, os teores de proteínas totais decresceram e os açúcares solúveis aumentaram durante os 30 primeiros dias em cultura e permaneceram constantes até os 120 dias. Por outro lado, os teores das proteínas totais apresentaram incremento de acordo com a progressão nos estádios de desenvolvimento dos embriões somáticos. Os teores de açúcares totais e de amido aumentaram nos estádios cordiforme e cotiledonar e diminuíram nos estádios torpedo e pré-cotiledonar. Esses compostos exercem papel central no desenvolvimento de embriões somáticos de Acca sellowiana.Fil: Cangahuala-Inocente, Gabriela Claudia. Universidade Federal de Santa Catarina; BrasilFil: Steiner, Neusa. Universidade Federal de Santa Catarina; BrasilFil: Maldonado, Sara Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Guerra, Miguel Pedro. Universidade Federal de Santa Catarina; Brasi

Intermittent stick-slip dynamics during the peeling of an adhesive tape from a roller

We study experimentally the fracture dynamics during the peeling at a constant velocity of a roller adhesive tape mounted on a freely rotating pulley. Thanks to a high speed camera, we measure, in an intermediate range of peeling velocities, high frequency oscillations between phases of slow and rapid propagation of the peeling fracture. This so-called stick-slip regime is well known as the consequence of a decreasing fracture energy of the adhesive in a certain range of peeling velocity coupled to the elasticity of the peeled tape. Simultaneously with stick-slip, we observe low frequency oscillations of the adhesive roller angular velocity which are the consequence of a pendular instability of the roller submitted to the peeling force. The stick-slip dynamics is shown to become intermittent due to these slow pendular oscillations which produce a quasi-static oscillation of the peeling angle while keeping constant the peeling fracture velocity (averaged over each stick-slip cycle). The observed correlation between the mean peeling angle and the stick-slip amplitude questions the validity of the usually admitted independence with the peeling angle of the fracture energy of adhesives.Comment: Forthcoming in Physical Review

Damage mechanisms in the dynamic fracture of nominally brittle polymers

Linear Elastic Fracture Mechanics (LEFM) provides a consistent framework to evaluate quantitatively the energy flux released to the tip of a growing crack. Still, the way in which the crack selects its velocity in response to this energy flux remains far from completely understood. To uncover the underlying mechanisms, we experimentally studied damage and dissipation processes that develop during the dynamic failure of polymethylmethacrylate (PMMA), classically considered as the archetype of brittle amorphous materials. We evidenced a well-defined critical velocity along which failure switches from nominally-brittle to quasi-brittle, where crack propagation goes hand in hand with the nucleation and growth of microcracks. Via post-mortem analysis of the fracture surfaces, we were able to reconstruct the complete spatiotemporal microcracking dynamics with micrometer/nanosecond resolution. We demonstrated that the true local propagation speed of individual crack fronts is limited to a fairly low value, which can be much smaller than the apparent speed measured at the continuum-level scale. By coalescing with the main front, microcracks boost the macroscale velocity through an acceleration factor of geometrical origin. We discuss the key role of damage-related internal variables in the selection of macroscale fracture dynamics.Comment: 18 pages, 21 figures, to appear in International Journal of Fractur

Fly a Rocket! ESA's hands-on programme for undergraduate students

The Fly a Rocket! programme is a hands-on project offered by the European Space Agency’s (ESA’s) Education Office in collaboration with Andøya Space Education and the Norwegian Space Agency (Norsk Romsenter). The programme represents a unique opportunity for entry-level university students from diverse backgrounds to build, test, and launch an actual sounding rocket and obtain otherwise unattainable practical experience. In September 2020, the ESA Education Office announced the third edition of the programme, for which 30 students from the ESA Member States and the Associate Member States were selected. Of these, 24 participated in the launch campaign which took place throughout the second week of October 2021 at the Andøya Space in Northern Norway. The Fly a Rocket! programme comprises an online pre-course with two assignments and a hands-on launch campaign. The pre-course is self-paced and aims to widen the participants’ understanding of basic rocket science topics such as the rocket principle, aerodynamics, and orbital mechanics in preparation for the campaign. During their stay at Andøya Space, the students were assigned to one of three teams, each with different responsibilities: Sensor Experiments, Telemetry and Data Readout, and Payload. As members of the Telemetry and Data Readout team, the authors’ role was to set up the student telemetry station and ensure that accurate data was collected from the sensors on the rocket. In addition, they were an integral part of the countdown procedure, operating two of the three telemetry stations used for the mission. Following the launch, all the teams worked in conjunction to analyse and present the data according to four previously defined scientific cases. This paper will be concerned with the activities carried out throughout Fly a Rocket!’s third cycle, with a particular focus on the work done by the Telemetry and Data Readout tea

A fotografia e a ciência

Na época da sua invenção, a fotografia não tinha um uso definido, mas desde o início a pesquisa científica em vários campos utilizou a fotografia como ferramenta e ilustração de resultados, contribuindo para o avanço da ciência no decorrer do século XIX. Aqui se ilustram algumas das mais importantes pesquisas que utilizaram fotografia nesse século e como esse processo evoluiu até o advento da imagem digital

Alopecia frontal fibrosante, ¿Variante del liquen plano pilaris o entidad propia?. Estudio clínico-patológico e inmunohistoquímico de 73 casos

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Medicina. Fecha de lectura: 05-04-2018Esta tesis tiene embargado el acceso al texto completo hasta el 05-10-201

Disorders Of Sex Development And Hypogonadism: Genetics, Mechanism, And Therapies.

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