Développement d'outils d’analyse de la motricité fine pour l’investigation de troubles neuromusculaires : théorie, prototype et mise en application dans le contexte des accidents vasculaires cérébraux

RÉSUMÉ Cette thèse examine la possibilité d’évaluer la susceptibilité à un accident vasculaire cérébral (AVC) à partir des attributs des mouvements humains. Ces travaux reposent sur l’hypothèse selon laquelle l’existence d’un état pré-AVC peut, dans certains cas, être détecté par l’évaluation de la santé neuromotrice du patient. À défaut de disposer de données longitudinales permettant d’étudier directement cette conjecture, nos résultats démontrent que le diagnostic des principaux facteurs de risque d’AVC est effectivement réalisable à partir des propriétés des mouvements. Ces conclusions sont tirées à la suite de l’analyse transversale des réponses de 120 sujets à neuf tests neuromoteurs. Par cette étude des liens entre la motricité et la présence de conditions menant potentiellement à l’AVC, on espère stimuler l’intérêt des chercheurs en santé pour l’hypothèse – rapportée de façon anecdotique par plusieurs cliniciens – de l’existence d’un état pré-AVC. Les investigations nécessaires à cette démonstration ont été menées dans le cadre de la Théorie Cinématique et suivent principalement trois axes directeurs, soit l’étude fondamentale du mouvement humain, le développement d’outils d’extraction permettant la modélisation lognormale des mouvements et l’analyse statistique des paramètres lognormaux dans le but du diagnostic des principaux facteurs de risque d’AVC (diabète, obésité, tabagisme, problèmes cardiaques, alcoolisme, hypertension et hypercholestérolémie). En introduction de la première partie de cette thèse sont répertoriés les différents indices disséminés dans la littérature scientifique étayant l’existence de liens entre les mouvements humains et les principaux facteurs de risque d’AVC. Observant que la présence de tels liens est supportée par l’état des connaissances actuelles, le paradigme offert par la Théorie Cinématique ainsi que la modélisation lognormale qui en découle sont adoptés, puis présentés. L’apparition de profils de forme lognormale au niveau des primitives du mouvement est ensuite expliquée d’un point de vue original. Une fois ces bases établies, il a été possible de procéder à l’analyse des données dont nous disposions, ce qui a mis en lumière un certain nombre de phénomènes fondamentaux relatifs à l’étude du contrôle moteur, dont trois sont particulièrement importants. En premier lieu, il a été relevé que la nature des mouvements est intrinsèquement proportionnelle.----------ABSTRACT This Ph. D. thesis investigates the brain stroke susceptibility assessment based on the movement analysis of data acquired using neuromuscular tests. This work is rooted in the hypothesis of the existence of a pre-stroke state which can sometimes be detected by looking at the properties of a patient’s neuromuscular system. As the study of this hypothesis would require longitudinal data that were unavailable, our analysis concentrates on the demonstration that the brain stroke risk factors can be diagnose from a human movement analysis. This conclusion derives from a transversal study of 120 subject’s responses to nine neuromuscular tests. It is hoped that this investigation on the links between fine motor control and brain stroke risk factors can stimulate the interest of the medical community for the anecdotic report, by some clinicians, of the possible existence of a pre-stroke state. The work presented herein was made under the Kinematic Theory and it follows three main axes which are 1) the fundamental study of human movements, 2) the design of extraction algorithms allowing the lognormal modeling of human motion, and 3) the statistical analysis of the kinematic parameters of human movements for the diagnosis of principal brain stroke risk factors. In the first part of this thesis, an overview is presented of the many observations scattered in the scientific literature concerning the link between the human movements and the main brain stroke risk factors (diabetes, obesity, cigarette smoking, cardiac problems, alcoholism, hypertension and hypercholesterolemia). Building on the observation that the existence of such a link is supported, a modeling framework is chosen and the lognormal models forming its foundations are reported from an original point of view. The application of this methodology to our database allowed the investigation of some fundamental phenomena concerning the study of motor control. Notably, the proportional nature of human motion is examined and compared to the serial representation of psychophysical processes. The delta-lognormal modeling of speed-accuracy tradeoffs (Fitts’ task) has also allowed the discovery of some fundamental aspects related to the control of this kind of movements, such as the increase of the coupling between the motor commands as the task becomes more difficult and the enhancement of the temporal coordination of the neuromuscular action as the geometrical properties of the task are scaled up

Identificación y caracterización de estrellas poco masivas y enenas marrones con el observatorio virtual

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Astrofísica y Ciencias de la Atmósfera, leída el 16-11-2015Two thirds of the stars in our galactic neighborhood (d < 10 pc) are M-dwarfs which also constitute the most common stellar objects in the Milky Way. This property, combined with their small stellar masses and radii, increases the likelihood of detecting terrestrial planets through radial velocity and transit techniques, making them very adequate targets for the exoplanet hunting projects. Nevertheless, M dwarfs have associated different observational difficulties. They are cool objects whose emission radiation peaks at infrared wavelengths and, thus, with a low surface brightness in the optical range. Also, the photometric variability as well as the significant chromospheric activity hinder the radial velocity and transit determinations. It is necessary, therefore, to carry out a detailed characterization of M-dwarfs before building a shortlist with the best possible candidates for exoplanet searches. Brown dwarfs (BDs) are self-gravitating objects that do not get enough mass to maintain a sufficiently high temperature in their core for stable hydrogen fusion. They represent the link between low-mass stars and giant planets. Due to their low temperatures, BDs emit significant flux at mid-infrared wavelength which makes this range very adequate to look for this type of objects. The Virtual Observatory (VO) is an international initiative designed to help the astronomical community in the exploitation of the multi-wavelength information that resides in data archives. In the last years the Spanish Virtual Observatory is conducting a number of projects focused on the study of substellar objects taking advantage of Virtual Observatory tools for an easy data access and analysis of large area surveys. This is the framework where this thesis has been carried out. This dissertation addresses three problems in the framework of low-mass stars and brown dwarfs, namely, the search for brown dwarf candidates crossmatching catalogues (Chapter 4), the search for nearby bright M dwarfs and the subsequent spectroscopic characterization (Chapter 5), and a study of binarity in mid to late-T brown dwarfs (Chapter 6); the first two topics use Virtual Observatory tools...Dos tercios de las estrellas que se encuentran en nuestra vecindad solar (d < 10 pc) son enanas de tipo espectral M, las cuales también constituyen los objetos más abundantes de la Vía Láctea. Esta característica, junto con el hecho de que son objetos con radios y masas pequeñas, hace que aumente la probabilidad de detectar planetas en zona de habitabilidad, haciendo de ellos objetos muy adecuados para proyectos de búsquedas de planetas extrasolares. Sin embargo, las enanas M tienen asociadas diferentes dificultades observacionales. Por un lado, son objetos fríos cuya máxima emisión electromagnética tiene lugar a longitudes de onda infrarroja y, por lo tanto, débiles en el óptico. Por otro lado, tanto la variabilidad fotométrica como la actividad cromosférica dificultan las detecciones de posibles exoplanetas por métodos de velocidad radial y de tránsito fotométrico. Por tanto, para poder construir una lista con los mejores candidatos para búsquedas de exoplanetas alrededor de enanas M, es necesario llevar a cabo previamente una caracterización detallada de las mismas. Las enanas marrones son objetos autogravitantes que no tienen la suficiente masa para alcazar la temperatura necesaria para llevar a cabo en su núcleo reacciones de fusión del hidrógeno de forma estable. Las enanas marrones representan, por tanto, la conexión entre las estrellas poco masivas y los planetas gigantes. Debido a sus bajas temperaturas, las enanas marrones emiten mayoritariamente su flujo en el infrarrojo medio, lo que hace de este rango del espectro electromagnético el adecuado para buscar este tipo de objetos. El Observatorio Virtual (OV) es una iniciativa internacional diseñada para ayudar a la comunidad astronómica en la explotación de la información multi-rango que reside en los archivos de datos. Aprovechando las herramientas del OV, que permiten un análisis y un acceso fácil a gran cantidad de cartografiados de gran campo, el Observatorio Virtual Español está llevando a cabo una serie de proyectos centrados en el estudio de objetos subestelares. Éste es elmarco en el que se inscribe el trabajo de tesis que aquí se presenta. Este trabajo aborda tres problemas en el marco de las estrellas poco masivas y enanas marrones: la búsqueda de candidatos a enanas marrones utilizando catálogos de grandes cartografiados (Capítulo 2), la búsqueda de enanasMcercanas y brillantes y su caracterización espectroscópica posterior (Capítulo 3), y un estudio de la binariedad de las enanas marrones T de subtipos intermedios y tardíos (Capítulo 4); los dos primeros capítulos estan basados en la utilización de herramientas del Observatorio Virtual..Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEunpu

Galaxy evolution as a function of mass and environment: giant and dwarf galaxies in superclusters and in the field

It has been known for decades that local galaxies can be broadly divided into two distinct populations (e.g. Hubble 1926, 1936; Morgan 1958; de Vaucouleurs 1961). The first population consists in red, passively-evolving, bulge-dominated galaxies mainly populated by old stars that, in the colourmagnitude diagram, makes up the “red sequence”, while the second population makes up the “blue cloud” of young, star-forming, disk-dominated galaxies (e.g. Strateva et al. 2001; Kauffmann et al. 2003a,b; Blanton et al. 2003a; Baldry et al. 2004; Driver et al. 2006; Mateus et al. 2006). It has also long been known that the environment in which a galaxy inhabits has a profound impact on its evolution in terms of defining both its structural properties and star-formation histories (e.g. Hubble & Humason 1931). In particular, passively-evolving spheroids dominate cluster cores, whereas in field regions galaxies are typically both star-forming and diskdominated (Blanton et al. 2005a). These differences have been quantified through the classic morphology–density (Dressler 1980) and star-formation (SF)–density relations (Lewis et al. 2002; G´omez et al. 2003). However, despite much effort (e.g. Treu et al. 2003; Balogh et al. 2004a,b; Gray et al. 2004; Kauffmann et al. 2004; Tanaka et al. 2004; Christlein & Zabludoff 2005; Rines et al. 2005; Baldry et al. 2006; Blanton, Berlind & Hogg 2007; Boselli & Gavazzi 2006; Haines et al. 2006a; Mercurio et al. 2006; Sorrentino, Antonuccio-Delogo & Rifatto 2006a; Weinmann et al. 2006a,b; Mateus et al. 2007), it still remains unclear whether these environmental trends are: (i) the direct result of the initial conditions in which the galaxy forms, whereby massive galaxies are formed earlier preferentially in the highest overdensities in the primordial density field, and have a more active merger history, than galaxies that form in the smoother low-density regions; or (ii) produced later by the direct interaction of the galaxy with one or more aspects of its environment, whether that be other galaxies, the intracluster medium, or the underlying dark-matter distribution. Several physical mechanisms have been proposed that could cause the transformation of galaxies through interactions with their environment such as ram-pressure stripping (Gunn & Gott 1972), galaxy harassment (Moore et al. 1996), and suffocation (also known as starvation or strangulation), in which the diffuse gas in the outer galaxy halo is stripped preventing further accretion onto the galaxy before the remaining cold gas in the disk is slowly consumed through star-formation (Larson, Tinsley & Caldwell 1980). The morphologies and star-formation histories of galaxies are also strongly dependent on their masses, with high-mass galaxies predominately passivelyevolving spheroids, and low-mass galaxies generally star-forming disks. A sharp transition between these two populations is found about a characteristic stellar mass of ∼3 × 1010M, corresponding to ∼M+ 1 (Kauffmann et al. 2003a,b). This bimodality implies fundamental differences in the formation and evolution of high- and low-mass galaxies. The primary mechanism behind this transition appears to be the increasing efficiency and rapidity with which gas is converted into stars for more massive galaxies according to the Kennicutt-Schmidt law (Kennicutt 1998; Schmidt 1959). This results in massive galaxies with their deep potential wells consuming their gas in a short burst (2 (Chiosi & Cararro 2002), while dwarf galaxies have much more extended star-formation histories and gas consumption time-scales longer than the Hubble time (van Zee 2001). In the monolithic collapse model for the formation of elliptical galaxies this naturally produces the effect known as “cosmic downsizing” whereby the major epoch of star-formation occurs earlier and over a shorter period in the most massive galaxies and progressively later and over more extended timescales towards lower mass galaxies. This has been confirmed observationally both in terms of the global decline of star-formation rates in galaxies since z∼1 (Noeske et al. 2007a,b) and the fossil records of low-redshift galaxy spectra (Heavens et al. 2004; Panter et al. 2007). Finally, in analyses of the absorption lines of local quiescent galaxies, the most massive galaxies are found to have higher mean stellar ages and abundance ratios than their lower mass counterparts, confirming that they formed stars earlier and over shorter time-scales (Thomas et al. 2005; Nelan et al. 2005). In this scenario, the mass-scale at which a galaxy becomes quiescent should decrease with time, with the most massive galaxies becoming quiescent earliest, resulting in the red sequence of passively-evolving galaxies being built up earliest at the bright end (Tanaka et al. 2005). However, the standard paradigm for the growth of structure and the evolution of massive galaxies within a CDM universe is the hierarchical merging scenario (e.g. White & Rees 1978; Kauffmann, White & Guideroni 1993; Lacey & Cole 1993) in which massive elliptical galaxies are assembled through the merging of disk galaxies as first proposed by Toomre (1977) (see also Struck 2005). Although downsizing appears at first sight to be at odds with the standard hierarchical model for the formation and evolution of galaxies, Merlin & Chiosi (2006) are able to reproduce the same downsizing as seen in the earlier “monolithic” models in a hierarchical cosmological context, resulting in what they describe as a revised monolithic scheme whereby the merging of substructures occurs early in the galaxy life (z > 2). Further contributions to cosmic downsizing and the observed bimodality in galaxy properties could come from the way gas from the halo cools and flows onto the galaxy (Dekel & Birnboim 2006; Kereˇs et al. 2005) and which affects its ability to maintain star-formation over many Gyrs, in conjunction with feedback effects from supernovae and AGN (e.g. Springel et al. 2005a; Croton et al. 2006). These mechanisms which can shut down star-formation in massive galaxies allow the hierarchical CDM model to reproduce very well the rapid early formation and quenching of stars in massive galaxies (e.g. Bower et al. 2006; Hopkins et al. 2006a; Birnboim, Dekel & Neistein 2007). In particular, the transition from cold to hot accretion modes of gas when galaxy halos reach a mass ∼1012M (Dekel & Birnboim 2006) could be responsible for the observed sharp transition in galaxy properties with mass. If the evolution of galaxies due to internal processes occurs earlier and more rapidly with increasing mass, then this would give less opportunity for external environmental processes to act on massive galaxies. Moreover, lowmass galaxies having shallower potential wells could be more susceptible to disruption and the loss of gas due to external processes such as ram-pressure stripping and tidal interactions. This suggests that the relative importance of internal and external factors on galaxy evolution and on the formation of the SF-, age- and morphology-density relations could be mass-dependent, in particular the relations should be stronger for lower mass galaxies. Such a trend has been observed by Smith et al. (2006) who find that radial age gradients (out to 1Rvir) are more pronounced for lower mass (σ<175kms−1) cluster red sequence galaxies than their higher mass subsample. With all this in mind, we undertook the work presented in this thesis studying galaxy evolution as a function of mass and environment (chapter 1). To this aim, we investigate the evolution of giant and dwarf galaxies in cluster environment (Part I) through the analysis of i) luminosity function and colour distribution (chapter 3), and ii) the fundamental plane of early-type galaxies (chapter 4). We extend, then, our analysis to a wide spread of environments, from the rarefied field to the high density regions, (Part II, chapters 6 and 7). This analysis allowed us to discriminate among the possible physical mechanisms which, driving the star-formation of giant and dwarf galaxies, are able to reproduce the observed bimodal galaxy distribution. Technical aspects of the dataset used throughout the present analysis are presented in chapters 2 and 5

SIMULATING SEISMIC WAVE PROPAGATION IN TWO-DIMENSIONAL MEDIA USING DISCONTINUOUS SPECTRAL ELEMENT METHODS

We introduce a discontinuous spectral element method for simulating seismic wave in 2- dimensional elastic media. The methods combine the flexibility of a discontinuous finite element method with the accuracy of a spectral method. The elastodynamic equations are discretized using high-degree of Lagrange interpolants and integration over an element is accomplished based upon the Gauss-Lobatto-Legendre integration rule. This combination of discretization and integration results in a diagonal mass matrix and the use of discontinuous finite element method makes the calculation can be done locally in each element. Thus, the algorithm is simplified drastically. We validated the results of one-dimensional problem by comparing them with finite-difference time-domain method and exact solution. The comparisons show excellent agreement

Book of abstracts of the 10th International Chemical and Biological Engineering Conference: CHEMPOR 2008

This book contains the extended abstracts presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, over 3 days, from the 4th to the 6th of September, 2008. Previous editions took place in Lisboa (1975, 1889, 1998), Braga (1978), Póvoa de Varzim (1981), Coimbra (1985, 2005), Porto (1993), and Aveiro (2001). The conference was jointly organized by the University of Minho, “Ordem dos Engenheiros”, and the IBB - Institute for Biotechnology and Bioengineering with the usual support of the “Sociedade Portuguesa de Química” and, by the first time, of the “Sociedade Portuguesa de Biotecnologia”. Thirty years elapsed since CHEMPOR was held at the University of Minho, organized by T.R. Bott, D. Allen, A. Bridgwater, J.J.B. Romero, L.J.S. Soares and J.D.R.S. Pinheiro. We are fortunate to have Profs. Bott, Soares and Pinheiro in the Honor Committee of this 10th edition, under the high Patronage of his Excellency the President of the Portuguese Republic, Prof. Aníbal Cavaco Silva. The opening ceremony will confer Prof. Bott with a “Long Term Achievement” award acknowledging the important contribution Prof. Bott brought along more than 30 years to the development of the Chemical Engineering science, to the launch of CHEMPOR series and specially to the University of Minho. Prof. Bott’s inaugural lecture will address the importance of effective energy management in processing operations, particularly in the effectiveness of heat recovery and the associated reduction in greenhouse gas emission from combustion processes. The CHEMPOR series traditionally brings together both young and established researchers and end users to discuss recent developments in different areas of Chemical Engineering. The scope of this edition is broadening out by including the Biological Engineering research. One of the major core areas of the conference program is life quality, due to the importance that Chemical and Biological Engineering plays in this area. “Integration of Life Sciences & Engineering” and “Sustainable Process-Product Development through Green Chemistry” are two of the leading themes with papers addressing such important issues. This is complemented with additional leading themes including “Advancing the Chemical and Biological Engineering Fundamentals”, “Multi-Scale and/or Multi-Disciplinary Approach to Process-Product Innovation”, “Systematic Methods and Tools for Managing the Complexity”, and “Educating Chemical and Biological Engineers for Coming Challenges” which define the extended abstracts arrangements along this book. A total of 516 extended abstracts are included in the book, consisting of 7 invited lecturers, 15 keynote, 105 short oral presentations given in 5 parallel sessions, along with 6 slots for viewing 389 poster presentations. Full papers are jointly included in the companion Proceedings in CD-ROM. All papers have been reviewed and we are grateful to the members of scientific and organizing committees for their evaluations. It was an intensive task since 610 submitted abstracts from 45 countries were received. It has been an honor for us to contribute to setting up CHEMPOR 2008 during almost two years. We wish to thank the authors who have contributed to yield a high scientific standard to the program. We are thankful to the sponsors who have contributed decisively to this event. We also extend our gratefulness to all those who, through their dedicated efforts, have assisted us in this task. On behalf of the Scientific and Organizing Committees we wish you that together with an interesting reading, the scientific program and the social moments organized will be memorable for all.Fundação para a Ciência e a Tecnologia (FCT

Collected Papers in Structural Mechanics Honoring Dr. James H. Starnes, Jr.

This special publication contains a collection of structural mechanics papers honoring Dr. James H. Starnes, Jr. presented at the 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference held in Austin, Texas, April 18-21, 2005. Contributors to this publication represent a small number of those influenced by Dr. Starnes' technical leadership, his technical prowess and diversity, and his technical breath and depth in engineering mechanics. These papers cover some of the research areas Dr. Starnes investigated, which included buckling, postbuckling, and collapse of structures; composite structural mechanics, residual strength and damage tolerance of metallic and composite structures; and aircraft structural design, certification and verification. He actively pursued technical understanding and clarity, championed technical excellence, and modeled humility and perseverance

Flight Mechanics/Estimation Theory Symposium, 1994

This conference publication includes 41 papers and abstracts presented at the Flight Mechanics/Estimation Theory Symposium on May 17-19, 1994. Sponsored by the Flight Dynamics Division of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers

Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

The proceedings of the SOAR workshop are presented. The technical areas included are as follows: Automation and Robotics; Environmental Interactions; Human Factors; Intelligent Systems; and Life Sciences. NASA and Air Force programmatic overviews and panel sessions were also held in each technical area