Este trabalho trata da reconstrução tomográfica bidimensional e tridimensional, a partir de projeções, visando sua utilização em qualquer aplicação que necessite do volume completo do objeto em questão ou que necessite das imagens adquiridas dos- objetos projetados. Propicie-se utilizar um dos métodos pelo qual a tomografia Computadorizada gera as fatias bidimensionais do corpo exposto, expandindo-o para a terceira dimensão. Para tornar isto possível, é necessário o estudo de métodos de reconstrução-bidimensional, bem como a implementação de um deles. E desenvolvido, então, um estudo sobre os conceitos da tomografia computadorizada, seus diferentes tipos, contendo, os métodos de reconstruçãobidimensional utilizado por elas, alem, dos métodos de aquisição das projeções dos objetos a serem reconstruídos. E apresentada uma proposta de trabalho bidimensional, onde será implementado, alem do algoritmo de reconstrução, o processo de aquisição das projeções do objeto em questão, bem como, a modelagem do mesmo. Além, do desenvolvimento de uma proposta de trabalho tridimensional, onde o método de reconstrução bidimensional desenvolvido será expandido para a terceira dimensão e implementado, juntamente com o processo de aquisição dos objetos tridimensionais projetados, bem como, a modelagem dos mesmos. Um protótipo para cada uma destas propostas é gerado, contendo, cada um, a etapa de aquisição das imagens projetadas, e a etapa de reconstrução do objeto. Tanto os resultados da imagem sendo reconstruída, como as imagens adquiridas dos objetos projetados, são Bravados em arquivos. Por fim, é apresentada uma analise dos resultados gerados por estes protótipos, no que diz respeito a convergência de seus algoritmos, e a melhor maneira de utilizá-los, a fim de se obter um melhor resultado. / This paper is about bidimensional and tridimensional tomographic reconstruction working with projections in order to use in any application that needs complete volume of the object used or that needs images of the projected objects acquired. It is used one of the methods by which the computerized tomography generates bidimensional slices of the exposed body expanding it to third dimension. In order to make it possible it was necessary to study bidimensional reconstruction methods, as well as implementing one of them. It is developed a study on concepts of computerized tomography, its different types, including bidimensional reconstruction methods used by them, besides the methods used to acquire projections of the objects to be reconstructed. It is presented a proposal of the bidimensional work, where it will be implemented, besides the reconstruction algorithm, the aquisition process of the projection of the meant objects, as well as modelling them. It is also developed a proposal of a tridimensional work, where the bidimensional reconstruction method developed will be implemented and expanded to third dimension as well as the process of aquisition of the tridimensionals projected objects as well as modelling them. A prototype of these proposals is generated , containing each one the aquisition step of the projected images and the reconstruction step of the object. The results of the reconstructed image as well as the acquired images of the projected objects are saved in files. Finally it is presented an analysis of the generated results of the prototypes as to the convergence of these algorithms and the best way to use them in order to obtain a better result.

Population projections for sub-Saharan Africa have, over the past decade, been corrected upwards because in a number of countries, the earlier declining trends in fertility stalled around 2000. While most studies so far have focused on economic, political, or other factors around 2000, here we suggest that in addition to those period effects, the phenomenon also matched up with disruptions in the cohort trends of educational attainment of women after the postindependence economic and political turmoil. Disruptions likely resulted in a higher proportion of poorly educated women of childbearing age in the late 1990s and early 2000s than there would have been otherwise. In addition to the direct effects of education on lowering fertility, these less-educated female cohorts were also more vulnerable to adverse period effects around 2000. To explore this hypothesis, we combine individual-level data from Demographic and Health Surveys for 18 African countries with and without fertility stalls, thus creating a pooled dataset of more than two million births to some 670,000 women born from 1950 to 1995 by level of education. Statistical analyses indicate clear discontinuities in the improvement of educational attainment of subsequent cohorts of women and stronger sensitivity of less-educated women to period effects. We assess the magnitude of the effect of educational discontinuity through a comparison of the actual trends with counterfactual trends based on the assumption of no education stalls, resulting in up to half a child per woman less in 2010 and 13 million fewer live births over the 1995-2010 period.

This dissertation models K-12 enrollment within an urban school district using two grade progression ratio (gpr)-based and two housing choice methods. The housing choice methods provide, for the first time, a new spatio-demographic model for projecting school enrollments by grade for any flexibly defined set of individual catchment areas. All methods use the geocoded pattern of individual, address-matched, enrollments within the study district but are different in the way they model this data to estimate key parameters. The conventional method projects the intra-urban pattern of enrollment by assuming no change in grade progression ratios (gprs), which are themselves functions of enrollment change. The adaptive kernel ratio estimation (KRE) of local gprs successfully predicts local changes in gprs from three preceding two-year periods of gpr change. The two housing choice methods are based on different mixtures of a generalized linear and a periodic model, each of which use housing counts and characteristics. Results are clearly sensitive to these differences. Using the above predictions of gpr change, the adaptive KRE enrollment projections are 4.1% better than those made using the conventional model. The two housing choice models were 2.0% less accurate than the conventional model for the first three years of the projection but were 5.1% more accurate than this model for the fourth and fifth years of the projection. Limitations are discussed. These findings help close a major gap in the literature of small-area enrollment projections, shed new light on spatial dynamics collected at areas below the scale of the school district, and permit new kinds of investigations of urban/suburban school district demography.

La mise en place des projections axonales est une étape clé du développement des circuits de la moelle épinière qui contrôle les fonctions motrices de l'individu. Il s'agit d'un processus complexe impliquant des mécanismes de spécification des neurones moteurs et des signalisations multiples assurant le guidage spécifique de chaque axone jusqu'à sa cible d'innervation. Les Sémaphorines de classe 3 (Sema3) sont des molécules secrétées dans l'environnement qui participent notamment au guidage des axones moteurs de la moelle épinière. De manière surprenante, les motoneurones expriment également eux-mêmes des Sema3. Mon équipe a déjà montré que l'expression intrinsèque de Sema3A par les motoneurones module leur sensibilité au Sema3A de l'environnement. Ce processus s'effectue par une régulation du niveau de son récepteur à la surface du cône de croissance, la structure terminale de l'axone responsable de la perception des signaux de guidage extracellulaires (Moret et al., 2007). Quelle est la portée de ce nouveau mécanisme modulatoire et peut-il être généralisé à d'autres membres de la famille des Sema3 exprimés dans les motoneurones ? Mon travail de thèse a permis de mettre en évidence ce rôle modulatoire d'un autre membre de la famille Sema3 : Sema3C, dons l'expression est restreinte à une sous-population de motoneurones, en plus d'une expression environnementale. Par des expériences de gain et de perte de fonction dans l'embryon de poulet, nous avons montré que l'expression motoneuronale de Sema3C module de manière différentielle ses deux récepteurs du niveau de récepteur entraînent une modulation de réponse à Sema3C mais aussi à Sema3A et Sema3F, qui se fixent respectivement sur Nrp1 et Nrp2. De plus, nous avons étudié la portée de ce mécanisme de modulation dans l'innervation des membres de l'embryon de poulet, ce modèle permettant l'étude des projections motoneuronales dans un environnement riche en Sema3. Ainsi, l'analyse in vivo des embryons de poulet pour lesquels l'expression intrinsèque de Sema3C dans les motoneurones a été manipulée a permis de montrer que la modulation de réponse aux Sema 3 de l'environnement contribue au positionnement stéréotypé des projection motrices dans le membre antérieur. Ce travail permet donc de proposer que l'expression d'un code de Sema 3 par les motoneurones confère aux différentes sous-populations une sensibilité spécifique aux gradients de Sema 3 présents dans l'environnement et assure ainsi une trajectoire stéréotypée des axones moteurs jusque dans leur territoire cible.

We construct a theory of general boundary value problems for differential operators whose symbols do not necessarily satisfy the Atiyah-Bott condition [3] of vanishing of the corresponding obstruction. A condition for these problems to be Fredholm is introduced and the corresponding finiteness theorems are proved.

The subject of the thesis is a study of the projections from low threshold oral and face afferents to the cerebral cortex and of descending motor control mechanisms originating in the cerebral cortex or the hypothalamus and influencing the jaw reflexes.Cats anaesthetized with chi oral ose were used for the experiments. Ipsi- and contralateral nerves from the oral cavity and the face were stimulated electrically. Cortical potentials were averaged and recorded. The location of the projections was related to the cytoarchi-tectonic areas of the cerebral cortex. It was found that the afferents projected to separate maximum points in areas 3a, 3b, 5a and 6aß. The projections to areas 3a and 3b were somatotopically organized, but the layout of the projections on the cortex was not facelike.The effect of monopolar anodal stimulation of the cerebral cortex on the monosynaptic jaw closing and the di synaptic jaw opening reflexes was investigated. A sequence of facilitation and inhibition of both reflexes was elicited by cortical stimulation. The effects were of short latency (2.5 ms) and could start with either facilitation or inhibition. The timecourse of the sequence was sinuslike with a period of 10 ms. The largest effect originated in the "sensory" areas 3a and 3b and not in the "motor" areas 4y and 6ag. It is suggested, that a tri gemino-cortico-tri geminai loop via area 3a may function in reflex modulation of jaw movements.The hypothalamic effects on the jaw reflexes were evoked by electrical stimulation in those parts of the hypothalamus, which are w known to generate defence, attack or feeding responses. A tenfold facilitation of the jaw closing reflex and a facilitation followed by almost complete inhibition of the jaw opening reflex were observed in the anaesthetized animal with intact cerebral cortex. The effects remained but were diminished in amplitude after cortical ablation. The descending path was located in the ventral midbrain tegmentum.It is suggested that the observed hypothalamo-tri geminai mechanism may exercise a tonic influence on the trigeminal motoneurones, thereby controlling the set points of the biting force and the rest position. The implications of this hypothesis on the etiology of bruxism and the myofascial pain-dysfunction are discussed. / <p>Härtill 3 rapporter.</p> / digitalisering@umu

This project implements a parallel algorithm for Computed Tomography based on the Algebraic Reconstruction Technique (ART) algorithm. This technique for reconstructing pictures from projections is useful for applications such as Computed Tomography (CT or CAT). The algorithm requires fewer views, and hence less radiation, to produce an image of comparable or better quality. However, the approach is not widely used because of its computationally intensive nature in comparison with rival technologies. A faster ART algorithm could reduce the amount of radiation needed for CT imaging by producing a better image with fewer projections. A reconstruction from projections version of the ART algorithm for two dimensions was implemented in parallel using the Message Passing Interface (MPI) and OpenMP extensions for C. The message passing implementation did not result in faster reconstructions due to prohibitively long and variant communication latency. The shared memory implementation produced positive results, showing a clear computational advantage for multiple processors and measured efficiency ranging from 60-95%. Consistent with the literature, image quality proved to be significantly better compared to the industry standard Filtered Backprojection algorithm especially when reconstructing from fewer projection angles. / October 2006

This thesis has investigated the possibility of improved soil temperature modeling using an updated version of an existing soil temperature model frequently used in catchment scale biogeochemical modeling. Future (2061-2090) snow dynamics and soil temperature was projected using ensemble of bias-corrected regional climate models (RCM). Effects over a north-south gradient of Sweden were analyzed using the four Swedish Integrated Monitoring (IM) catchments as study sites. Model calibration was applied on the study sites using daily observations of soil temperature for 1996-2008. The calibrated models were able to simulate soil temperature at different depths in the soil profile in a very accurate way in all IM sites. The lowest validation NS-value (objective criterion used for measuring goodness of fit) recorded in the study was 0.93. Even though the overall model performances were good, the simulations had problem of duplicating some of the winter temperatures at the northernmost site, Gammtratten. Whether the updated soil temperature model offered an improvement of the existing model is therefore debatable. The future simulations showed increasing soil temperatures at all study sites on annual basis, more in the south than in the north. Annual soil temperatures were projected to increase by 1.31 – 2.33 °C for the different study sites. Winter soil temperatures were clearly higher than during 1996-2008 for the two southernmost sites, whilst Gammtratten in the north, had colder winter soil temperatures. At the midmost catchment, winter soil temperatures were quite similar to that of the test period. Whether the cold winter soil temperatures at Gammtratten were a result of snow loss was ambiguous. The results from the future simulations showed the complexity of predicting soil temperature and strengthened the conclusion among scientists that any general assumptions of future soil temperature based on e.g. air temperature cannot be done. / Det här examensarbetet har undersökt möjligheterna till förbättrad modellering av marktemperaturer genom införandet av en uppdaterad version av en tidigare modell, frekvent använd vid biokemisk modellering på avrinningsområdesnivå. Vidare har framtida (2061-2090) snödynamik och marktemperaturer simulerats genom att en ensemble av bias –korrigerad klimatdata används för att driva modellen. Nutida (1996-2008) klimatdata, samt marktemperatursdata för kalibrering och validering av modellen, tillhandahölls från de fyra platser som ingår i det Svenska miljöövervakningsprogrammet (IM). Dessa platser kom att utgöra en syd-nordlig gradient, längs vilken resultaten analyserades.   Det generella omdömet från kalibreringen av modellen var att den kunde erbjuda en bra representation av verkliga förhållanden i fråga om marktemperatur. Det lägsta NS-värdet (objektivt kriterium använt för att mäta modellens passningsgrad) som uppmättes under valideringen var 0,93, vilket ansågs vara mycket högt. Dock hade modellen svårigheter att efterlikna verkliga markförhållanden vid Gammtratten under vintermånaderna, vilket föranledde slutsatsen att vidare undersökningar behöver göras för att kunna fastställa om modellen utgör en förbättring av den tidigare existerande versionen.   De framtida simuleringarna visade högre årliga marktemperaturer i jämförelse med dagen värden, särskilt i söder. Baserat på simuleringarna är det troligt att framtida marktemperaturer kommer att vara mellan 1,31 och 2,33 °C högre än idag. Beträffande säsongsmässig variation var maktemperaturerna under vintern högre än dagens värden för de två sydliga platserna medans de var lägre för den nodligaste platsen (Gammtratten). Huruvida de kallare simulerade marktemperaturerna vid Gammtratten var en konsekvens av ett mindre isolerande snötäcke var tvetydigt. Resultaten från de framtida simuleringarna har visat på komplexiteten i att förutspå framtida marktemperaturer och har stärkt uppfattningen om att några generella slutsatser om vad t.ex. högre lufttemperaturer kommer få för konsekvenser för framtida marktemperaturer inte kan göras.

Cette thèse traite des domaines suivant en Apprentissage Automatique: la théorie des Bandits, l'Apprentissage statistique et l'Apprentissage par renforcement. Son fil rouge est l'étude de plusieurs notions d'adaptation, d'un point de vue non asymptotique : à un environnement ou à un adversaire dans la partie I, à la structure d'un signal dans la partie II, à la structure de récompenses ou à un modèle des états du monde dans la partie III. Tout d'abord nous dérivons une analyse non asymptotique d'un algorithme de bandit à plusieurs bras utilisant la divergence de Kullback-Leibler. Celle-ci permet d'atteindre, dans le cas de distributions à support fini, la borne inférieure de performance asymptotique dépendante des distributions de probabilité connue pour ce problème. Puis, pour un bandit avec un adversaire possiblement adaptatif, nous introduisons des modèles dépendants de l'histoire et traduisant une possible faiblesse de l'adversaire et montrons comment en tirer parti pour concevoir des algorithmes adaptatifs à cette faiblesse. Nous contribuons au problème de la régression en montrant l'utilité des projections aléatoires, à la fois sur le plan théorique et pratique, lorsque l'espace d'hypothèses considéré est de dimension grande, voire infinie. Nous utilisons également des opérateurs d'échantillonnage aléatoires dans le cadre de la reconstruction parcimonieuse lorsque la base est loin d'être orthogonale. Enfin, nous combinons la partie I et II : pour fournir une analyse non-asymptotique d'algorithmes d'apprentissage par renforcement; puis, en amont du cadre des Processus Décisionnel de Markov, pour discuter du problème pratique du choix d'un bon modèle d'états.

The exhibition Is There No One in the World Who Can Fly? consists of three connected bodies of works. Life On Earth is a series of photo-performances exhibited on digital screens. Some of the images are still others are animated; they all propose that the body is a transmitter that breaths in content and breaths it out as a visual shape in the form of extensions, armatures or expulsions. Mammal is a large-scale video projection of a multi-breasted female figure projected on a free-standing wall. The breasts are animated and stretch out to explore and search the surrounding space. Worknest is a series of videos about the act of working which are projected onto the floor and appear as a community of guarded openings into tunnels beneath the ground.