To “Sketch-a-Scratch”

A surface can be harsh and raspy, or smooth and silky, and everything in between. We are used to sense these features with our fingertips as well as with our eyes and ears: the exploration of a surface is a multisensory experience. Tools, too, are often employed in the interaction with surfaces, since they augment our manipulation capabilities. “Sketch-a-Scratch” is a tool for the multisensory exploration and sketching of surface textures. The user’s actions drive a physical sound model of real materials’ response to interactions such as scraping, rubbing or rolling. Moreover, different input signals can be converted into 2D visual surface profiles, thus enabling to experience them visually, aurally and haptically

Slab detachment dynamics: insights from 0D to 3D numerical experiments

Slab detachment is a process that has been invoked to explain rapid uplift, deep seismicity, and magmatic activity in several active orogens (e.g., Alps, Himalaya). However, it is not yet clear to which extent slab detachment is the primary cause of these phenomena. Thus, deciphering the physical processes controlling detachment is important to understand its impact on the post-collisional evolution of orogens. Here we employ numerical models to investigate the nonlinear coupling between mantle flow and slab detachment. Due to the three-dimensional nature of slab detachment and the variety of involved processes, it is daunting to pinpoint the first order controls on the time scale of this process. We therefore investigated this issue by first developing a simplified 0D necking model that describes the temporal evolution of the thickness of a detaching slab. Our 0D numerical experiments highlight the importance of slab temperature and activation volume of the slab and upper mantle. The combination of these two parameters can delay the detachment process and yield different transient surface and stress signals. These results have been confirmed with 2D numerical experiments The same insights have been furtherly validate with 3D numerical experiments, allowing us to focus our attention on the radius of curvature of the subduction zone and on the lateral heterogeneities. Based on these findings, we then used 2D and 3D numerical models to further determine higher dimensional geometrical effects on slab detachment. For more complex slab geometries, higher dimensional results deviate from the 0D predictions. Nevertheless, the combination of 0D and 2D/3D numerical models allows to determine first order controls on slab detachment

CD4+ T celll differentiation explored through Markov process

In this thesis I discuss a project in collaboration with Professor Sarah Teichmann’s group (MRC Laboratory of Molecular Biology and EMBL-EBI, Cambridge). We have been working on a cell transformation process of naive cells into Th2 cells (also in this case the data has been purposely derived in Teichmann’s lab). Here we investigate population data on cells at different stages of differentiation (FACS data) which contain a wealth of information on the microscopic nature of the events leading na ̈ıve cells becoming Th2 cells. Many differentiation processes occur hand-in-hand with a change in cell cycle status: this can be cell cycle arrest, as in the monocyte to macrophage transition, cell cycle entry, as for the pre-adipocyte to adipocyte differentiation, and entry and subsequent cell division, as in T helper (Th) cell differentiation. Th cell differentiation is the process where naive CD4+ T cells transition to effector lymphocytes and is central to mammalian adaptive immunity. After antigen stimulation of the T-cell receptor in the preence of specific cytokines, naive Th cells start dividing rapidly to reach a differentiated state, with the best understood being Th1, Th2, Th17 and pTregs. So far, several master regulators have been identified and there is considerable insight into their regulatory networks. While much is known in CD8+ (killer) T cells, the expansion of CD4+ (helper) T cells during an infection is less well understood at the cellular and molecular levels. How does the coupling between differentiation and the cell cycle occur in CD4+ T cells? Are the two processes indipendent and orthogonal or linked through molecules and hence intertwined? Does differentiation occur in a gradual manner as suggested by many studies, including a recent single-cell analysis of lungh epithelial development or in a cooperative switch-like manner? Here, we use a new approach to tackle these questions, which is to extract biologically intermediate states of differentiation from a single chronological time point. By sorting out separate cell populations from a single cell culture of asynchronized, dividing cells, we aimed to reduce the biological variability in cytokine exposure, confluence, etc. With this approach we minimize the biological noise in our data and focus entirely on the processes of cell division and differentiation. We used in-depth transcriptome profiling coupled with bioinformatics data analysis to identify three major cell states during Th2 differentiation. By counting cells in each cell generation using flow cytometry, we modelled the rates of death, division and differentiation using a discrete time Markov branching process. This model gives information about which kind of transitions are most likely to happen at single cell level; for example, it can say if an activated cell (still not differentiated) is most likely to give rise to differentiated cells through a duplication or in a direct way. This revealed a higher cell division rate for differentiated cells compared with proliferating, activated cells. We validate those finding by DNA staining and by single-cell live imaging of T h2 cells. These in vitro data supported the idea of a fine-tuned relationship between cell cycle speed and differentiation status in CD4+T cells

Turbulence-distortion analysis for leading-edge noise-prediction enhancement

The analytical model for leading-edge noise prediction formulated by Amiet, developed for a flat plate, relates the far-field acoustic pressure to the upstream inflow conditions, modeled by canonical turbulence spectra. The inaccurate results provided by this low-fidelity method when applied to thick airfoils has been attributed to the distortion experienced by turbulent structures when approaching the airfoil, not modeled in the original formulation of Amiet. The first attempts to account for the effects of this physical mechanism consisted of modifying the term representing the incoming turbulence by means of the analytical results of the rapid distortion theory, obtaining a promising improvement of the noise-prediction accuracy. This paper aims to set up the physical framework to investigate the relation between turbulence distortion and noise-generation mechanisms with the purpose of enhancing inflowturbulence noise modeling. A numerical database obtained for a rod-airfoil configuration has been chosen to allow the analysis of the vortex dynamics when interacting with a body. The analysis of the velocity field near the leading edge has highlighted that the extension of the region where turbulence distortion occurs depends on the size of the incoming turbulence structures. Furthermore, surface pressure fluctuations have been observed to peak at the same position along the airfoil where the pressure gradient in the streamwise direction is maximum. A novel approach has been proposed to account for turbulence distortion in Amiet’s model by using as input the turbulence spectrum directly sampled in this position. A satisfactory agreement with the prediction provided by the solid formulation of the Ffowcs-Williams and Hawkings analogy has been obtained

Climatic Variability Effects on the Vegetation State and Water Coverage in a Watershed of Temperate Climate (Argentina)

El área de estudio se encuentra en el sur de la provincia de Buenos Aires (Argentina) y forma parte de la región pampeana Argentina. Se caracteriza por el predominio de un clima templado. El objetivo de este trabajo fue cuantificar los efectos de los eventos climáticos extremos en el estado de la vegetación y la extensión del área cubierta por agua, en una cuenca hidrográfica de clima templado (cuenca del arroyo Napostá Chico). El período de estudio fue 2000-2013. La metodología incluyó el análisis de serie de datos del Índice Estandarizado de Precipitación y Evapotranspiración (SPEI) a escala 1, 3 y 12 meses, para la detección de eventos climáticos extremos. Mediante interpretación visual de imágenes satelitales, se determinaron las diferentes coberturas de la cuenca y se calculó el Índice de Vegetación de Diferencia Normalizada (en inglés, NDVI). Además, se delinearon los cuerpos de agua del área de estudio mediante procesamiento digital de imágenes satelitales Landsat 5 TM y 7 ETM+ correspondientes a los eventos extremos definidos mediante la aplicación del SPEI. Los mismos fueron definidos para 2001 y 2004 (eventos húmedos), 2008 y 2009 (eventos secos) y 2007 (evento normal). El estado de la vegetación así como también las extensiones cubiertas por los cuerpos de agua, presentaron variaciones a lo largo de los diferentes eventos climáticos extremos. La vulnerabilidad climática de la cuenca y el conocimiento de los eventos de precipitación extremos es fundamental para la gestión de los recursos hídricos y de las actividades agroeconómicas que allí se desarrollan.The study area is located in the south of the Buenos Aires province (Argentina) and it is included in the “Región Pampeana” argentina. It is characterized by a template climate. The aim of this work was quantify the extreme climatic events effects on vegetation state and area covered by water, in a watershed of a template climate (Napostá Chico creek). The study period was 2000-2013. The methodology included the analysis of Standardized Precipitation- Evapotranspiration Index (SPEI) in 3 temporal scales (1, 3 and 12 months) in order to detect the extreme climatic events. Several land covers were defined by visual interpretation of satellite image and Normalized Difference Vegetation Index (NDVI) application. Landsat 5 TM and 7 ETM+ satellite images were processed for water bodies delineation. The extreme events were defined during 2001 and 2004 (wet years), 2008 and 2009 (dry years) and 2007 (normal year). As a result, state of vegetation and area covered by water showed variations among extreme events. Knowledge about climatic vulnerability of the watershed and the extreme events occurrence is essential for the hydric resources management and economic activities of the study region.Fil: Brendel, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Bohn, Vanesa Yael. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Avaliação da evolução do índice de vegetação de teledetecção usando de técnicas de processamento de imagens

Vegetation has a substantial role as an indicator of anthropic effects, specifically in cases where urban planning is required. This is especially the case in the management of coastal cities, where vegetation exerts several effects that heighten the quality of life (alleviation of unpleasant weather conditions, mitigation of erosion, aesthetics, among others). For this reason, there is an increased interest in the development of automated tools for studying the temporal and spatial evolution of the vegetation cover in wide urban areas, with an adequate spatial and temporal resolution. We present an automated image processing workflow for computing the variation of vegetation cover using any publicly available satellite imagery (ASTER, SPOT, LANDSAT, MODIS, among others) and a set of image processing algorithms specifically developed. The automatic processing methodology was developed to evaluate the spatial and temporal evolution of vegetation cover, including the Normalized Difference Vegetation Index (NDVI), the vegetation cover percentage and the vegetation variation. A prior urban area digitalization is required. The methodology was applied in Monte Hermoso city, Argentina. The vegetation cover per city block was computed and three transects over the city were outlined to evaluate the changes in NDVI values. This allows the computation of several information products, like NDVI profiles, vegetation variation assessment, and classification of city areas regarding vegetation. The information is available in GIS-readable formats, making it useful as support for urban planning decisions.A vegetação tem um papel importante como indicador de efeitos antrópicos, especificamente nos casos em que o planejamento urbano é necessário. Este é especialmente o caso na gestão de cidades costeiras, onde a vegetação exerce diversos efeitos que elevam a qualidade de vida (alívio de condições climáticas desagradáveis, mitigação da erosão, estética, entre outras). Por essa razão, há um interesse crescente no desenvolvimento de ferramentas automatizadas para o estudo da evolução temporal e espacial da cobertura vegetal em grandes áreas urbanas, com adequada resolução espacial e temporal. Apresentamos um fluxo de trabalho automatizado de processamento de imagens para calcular a variação da cobertura vegetal usando qualquer imagem de satélite publicamente disponível (ASTER, SPOT, LANDSAT, MODIS, entre outros) e um conjunto de algoritmos de processamento de imagem desenvolvidos especificamente. A metodologia de processamento automático foi desenvolvida para avaliar a evolução espacial e temporal da cobertura vegetal, incluindo o Índice de Vegetação da Diferença Normalizada (NDVI), o percentual de cobertura vegetal e a variação da vegetação. Uma digitalização prévia da área urbana foi necessária. A metodologia foi aplicada na cidade de Monte Hermoso, na Argentina. A cobertura vegetal por quarteirão foi computada e três transectos sobre a cidade foram delineados para avaliar as mudanças nos valores de NDVI. Isso permite o cálculo de vários produtos de informação, como perfis de NDVI, avaliação da variação da vegetação e classificação das áreas da cidade em relação à vegetação. A informação está disponível em formatos legíveis pelo GIS, tornando-a útil como suporte para decisões de planejamento urbano.Fil: Revollo Sarmiento, Natalia Veronica. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Revollo Sarmiento, Gisela Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Huamantinco Cisneros, María Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Delrieux, Claudio Augusto. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; Argentin

Autism spectrum disorders and intestinal microbiota

Through extensive microbial-mammalian co-metabolism, the intestinal microbiota have evolved to exert a marked influence on health and disease via gut-brain-microbiota interactions. In this addendum, we summarize the findings of our recent study on the fecal microbiota and metabolomes of children with pervasive developmental disorder–not otherwise specified (PDD-NOS) or autism (AD) compared with healthy children (HC). Children with PDD-NOS or AD have altered fecal microbiota and metabolomes (including neurotransmitter molecules). We hypothesize that the degree of microbial alteration correlates with the severity of the disease since fecal microbiota and metabolomes alterations were higher in children with PDD-NOS and, especially, AD compared to HC. Our study indicates that the levels of free amino acids (FAA) and volatile organic compounds (VOC) differ in AD subjects compared to children with PDD-NOS, who are more similar to HC. Finally, we propose a new perspective on the implications for the interaction between intestinal microbiota and AD