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A new biased estimator for multivariate regression models with highly collinear variables / Ein neuer verzerrter Schätzer für lineare Regressionsmodelle mit stark korrelierten RegressorenWissel, Julia January 2009 (has links) (PDF)
Es ist wohlbekannt, dass der Kleinste-Quadrate-Schätzer im Falle vorhandener Multikollinearität eine große Varianz besitzt. Eine Möglichkeit dieses Problem zu umgehen, besteht in der Verwendung von verzerrten Schätzern, z.B den Ridge-Schätzer. In dieser Arbeit wird ein neues Schätzverfahren vorgestellt, dass auf Addition einer kleinen Konstanten omega auf die Regressoren beruht. Der dadurch erzeugte Schätzer wird in Abhängigkeit von omega beschrieben und es wird gezeigt, dass dessen Mean Squared Error kleiner ist als der des Kleinste-Quadrate-Schätzers im Falle von stark korrelierten Regressoren. / It is well known, that the least squares estimator performs poorly in the presence of multicollinearity. One way to overcome this problem is using biased estimators, e.g. ridge regression estimators. In this study an estimation procedure is proposed based on adding a small quantity omega on some or each regressor. The resulting biased estimator is described in dependence of omega and furthermore it is shown that its mean squared error is smaller than the one corresponding to the least squares estimator in the case of highly correlated regressors.
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Documentation and analysis of plastic fingerprint impressions involving contactless three-dimensional surface scanningZhang, Wuchen 18 June 2019 (has links)
Fingerprint impressions are frequently encountered during the investigation of crime scenes, and may establish a crucial linkage between the suspect and the crime scene. Plastic fingerprint impressions found at crime scenes are often transient and delicate, leaving photography the sole means of documentation. A traditional photography approach can be inadequate in documenting impressions that contain three-dimensional (3D) details due to the limitations of camera and lighting conditions on scene. In this study, 3D scanning was proposed as a novel method for the documentation of plastic fingerprints. Structured-light 3D scanning (SLS) captures the distortion of projected light patterns on the subject to obtain its 3D profile, which allows fast acquisition of the complete 3D geometric information of the surface. The contactless operation of SLS also eliminates the risk of destroying fragile evidence, making it a sound choice for forensic applications.
In this study, the feasibility of 3D scanning of plastic fingerprint impressions was evaluated and compared with traditional photography regarding the quantity and quality of perceptible friction ridge features. Attempts were made to develop a procedure to extract curvature features from 3D scanned fingerprints and flatten the friction ridge features into two-dimensional (2D) images to allow direct comparison with the traditional photography method in the CSIpix® Matcher and NFIQ 2.0 software. One of the developed methods (3DR) utilizing a discrete geometry operator and convexity features outperformed traditional photography, both in minutiae count and match quality, while traditional photography could not always capture enough high-quality minutiae for comparisons, even after digital enhancement. The reproducibility of the 3D scanning process was evaluated using 3D point cloud statistics. The pair-wise mean distance and standard deviation were calculated for four levels of comparisons with theoretically increasing disparity, including pairs of scans of the same impressions. The results showed minimal shape deviation from scan to scan for the same impression, but high variations for different impressions.
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Avaliação comparativa da Borda WALA em mandíbulas secas e modelos e da sua mensuração em radiografias oclusais e tomografias / A comparative assessment of the WALA ridge in dissected mandibles and cast models as well as its measurement in occlusal radiographies and tomographiesMoura Neto, Gastão 06 May 2010 (has links)
Introdução: a determinação da Borda WALA em modelos de gesso permitia defini-la como uma linha imaginária utilizada no planejamento, seguimento e finalização de casos clínicos. Procurou-se determinar a Borda WALA em modelos de gesso de pacientes ortodônticos, mandíbulas secas, radiografias oclusais e cortes tomográficos dos pacientes e mandíbulas respectivas. O objetivo foi detectar a viabilidade de mensurar e determinar, por um método reproduzível, a Borda WALA em radiografias oclusais e cortes tomográficos. Metodologia: foram utilizados modelos, radiografias oclusais e tomografias de feixe cônico de 12 pacientes ortodônticos, e 12 mandíbulas e suas respectivas radiografias oclusais e cortes tomográficos. As mensurações tomográficas foram realizadas, em todos os dentes, do ponto mais vestibular das raízes dentárias no nível cervical até a parte mais externa da cortical óssea vestibular. Nas mandíbulas secas e nos modelos, as medidas verticais partiam do ponto EV até a linha de grafite que determinou o ponto vestibular mais externo. Resultados: os arcos correspondentes à Borda WALA obtidos nos modelos de gesso e nas mandíbulas secas se equivaleram em sua forma, sendo um pouco menores, em sua dimensão, nos modelos. Os arcos obtidos a partir das mensurações realizadas em radiografias oclusais e cortes tomográficos se equivaleram, em sua forma, nos modelos e mandíbulas, com correlação fortemente positiva, detectada pelo Coeficiente de Correlação de Pearson. Conclusões: 1. a Borda WALA não representa uma estrutura anatômica, mas uma medida/anagrama/referência a ser mensurada e utilizada nos tratamentos ortodônticos e ortopédicos; 2. a Borda WALA não deve ser considerada uma linha imaginária, mas um arco a ser determinado por medidas que devem servir de parâmetro nas correções das alterações da oclusão e alinhamento dos dntes inferiores; 3. em seu contorno e forma, as medidas obtidas nos modelos e nas mandíbulas, assim como nas radiografias oclusais e tomografias de feixe cônico, se equivaleram estatisticamente. Nas radiografias oclusais dos pacientes, houve dificuldades técnicas para a obtenção de imagens que permitissem uma mensuração precisa na determinação da Borda WALA. Nos cortes tomográficos, as medidas realizadas para determinação da Borda WALA reproduziram, com coeficiente de correlação fortemente positivo, a dimensão e a forma obtidas em medidas nos modelos de gesso e nas mandíbulas secas. Em suma, a determinação da Borda WALA a partir de cortes tomográficos transversais no nível cervical dos dentes inferiores é viável, pois a dimensão e a forma do arco obtido se equivalem estatisticamente ao arco obtido pelas medidas realizadas em modelos de gesso e mandíbulas secas. / Introduction: The WALA ridge is an imaginary line determined in cast models and used as reference for orthodontic treatment planning, execution and finalization. In the following study, the WALA ridge was defined in cast models of orthodontic patients, dissected mandibles, occlusal radiographies and tomographic slices of patients and respective mandibles aiming to find a reproducible method for determining the WALA ridge in occlusal radiographies and tomographic slices. Methodology: The sample comprised 12 cast models, occlusal radiographies and cone beam tomographies of orthodontic patients and 12 dissected mandibles, their respective occlusal radiographies and tomographic slices. Tomographic measurements were made in all teeth from the most buccal point of dental roots on their cervical level until the most external and anterior cortical line of bone. Vertical measurements on dissected mandibles and cast models were taken from FA point until the pencil line that determined the most external edge of bone around mandibular teeth. Results: The arches corresponding to the WALA ridge obtained from cast models and dissected mandibles were equivalent in form but a little smaller in size for cast models. The arches obtained from occlusal radiographies and tomographic slices were equivalent in form to the ones obtained from models and dissected mandibles, with a high positive correlation of proportion statistically confirmed by Pearsons coefficient. Conclusion: 1. The WALA ridge is not an anatomical structure, but a measurement/anagram/reference to be measured and used during orthodontic and orthopedic treatment. 2. The WALA ridge should not be considered an imaginary line, but an arch to be determined by measurements and used as parameter when correcting the occlusion of misalignment of inferior teeth; 3. The measurements obtained from models and dissected mandibles, as well as from occlusal radiographies and cone beam tomographies were equivalent in shape and form. Obtaining the WALA ridge from occlusal radiographies in patients involve technical difficulties to acquire a good image for precise measurement. Tomographic measurements to determine the WALA ridge were reproducible, with a high positive correlation coefficient to the dimension and form obtained from cast models and dissected mandible measurements. To sum up, determining the WALA ridge from tomographic transversal slices on the cervical level of inferior teeth is viable, since the dimension and arch form are statistically equivalent to the arch form obtained from cast models and dissected mandibles.
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"Avaliação da retenção de prótese total bimaxilar em função das características da área basal" / Evaluation of the retention of bimaxillay complete denture in function of the characteristics of the basal area.Cunha, Eudes Francisco da Silva 28 January 2005 (has links)
Nesta pesquisa, em 14 pacientes da Clínica de Prótese Total da Faculdade de Odontologia da Universidade de São Paulo, foi realizada a avaliação da retenção de prótese total bimaxilar em função das características da área basal por três avaliadores clínicos experientes e calibrados. Foram avaliadas as retenções vertical anterior, laterais direita e esquerda e póstero-anterior e as características da área basal: forma, tamanho, altura e tipo do rebordo e a consistência da fibromucosa. Por se tratarem de opiniões, os dados foram transformados em escores e submetidos à análise de variância não paramétrica com o teste KRUSKAL-WALLIS e paramétrica com o teste ANOVA. Concluiu-se que, na maxila, a retenção das próteses totais novas foi influenciada positivamente pelo tipo rebordo paralelo e pela consistência resiliente da fibromucosa, enquanto na mandíbula influenciaram o tamanho médio e a forma oval. As opiniões sobre a retenção e o grau de satisfação entre os avaliadores e os pacientes foram as mesmas. / In this research, a evaluation of the retention of bimaxilar complete denture in function of the characteristics of the basal area by three calibrated experienced clinician was accomplished in 14 patients of the Odontology College of the University of São Paulo. The anterior vertical retention, right lateral retention, left lateral retention, posteroanterior retention and rigde shape, ridge size, rigde height, ridge type and the fibromucosa consistency were evaluated. Because of they are opinions, the data were trans formed in scores and submitted to the no parametric variance analysis with the KRUSKAL-WALLIS and ANOVA parametric tests. Conclusion, in the maxilla, the retention of the new complete denture, was positively influenced by the parallel rigde type and by the resilient consistency of the fibromucosa, while in the mandible, the decisive factors of the retention were the medium size of the rigde and the oval shape of this. The opinions about the retention and the level of satisfaction had been the same among the appraisers and patients.
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Estudo morfotectônico da região da serra de São Pedro e do baixo Piracicaba/SP / Morphotectonic Study of the São Pedro Ridge and Lower Piracicaba Region/SPPinheiro, Marcos Roberto 30 October 2014 (has links)
As cuestas são definidas como uma forma de relevo dissimétrico, composta por uma vertente em declive íngreme de um lado e uma rampa em declive suave no reverso, decorrente da erosão diferencial das rochas. A região da Serra de São Pedro/SP, área de ocorrência de basaltos juro-cretáceos (topo da escarpa) e arenitos eólicos (escarpa e glacis) do Triássico ao Cretáceo Médio, consiste em uma das zonas mais típicas das cuestas na Bacia do Paraná, porém a configuração geometrizada do relevo da área, do sistema fluvial e até do baixo rio Piracicaba sugerem um controle tectônico das formas. Nesse sentido, o objetivo deste trabalho foi verificar o possível controle tectônico no relevo da Serra de São Pedro e do Baixo Piracicaba, focalizando a ação da Neotectônica, tendo como hipótese a existência de um forte controle das estruturas modernas sobre as formas. Os resultados mostraram que a atividade neotectônica na área é caracterizada principalmente pela atividade de falhas transcorrentes e normais subverticais WNW-ESE, W-E, NW-SE e NE-SW, ambas de pequeno rejeito e de impacto reduzido na morfologia do relevo. A influência das estruturas nas formas é mais intensa no sistema fluvial, comandando a dissecação do relevo de toda a área a partir de linhas estruturais que correspondem aos planos de juntas, grandes fraturamentos e falhas, ainda que a tectônica recente seja responsável pelo controle da direção apenas dos canais de 1º e 2º ordens. A Neotectônica condiciona ainda a formação de facetas triangulares na frente da escarpa da Serra de São Pedro, provoca perturbações de depósitos fluviais quaternários, anomalias no perfil longitudinal dos rios e inflexões dos interflúvios e canais de drenagem, além de pequenos basculamentos de blocos que causam a formação e degradação de terraços fluviais nos afluentes da margem direita do baixo Piracicaba. Essas informações são coerentes com os dados das estruturas medidas e materiais descritos em campo, bem como com as informações do contorno estrutural e dados geofísicos da área. Apesar do claro registro de neotectônica na região da Serra de São Pedro e do Baixo Piracicaba, os resultados demonstraram que a magnitude dessa atividade é reduzida e o seu impacto no relevo é pequeno, sendo que a configuração geomorfológica atual é mais influenciada por fatores litológicos, pela disposição das camadas sedimentares das rochas, pelos (paleo)climas e pela orientação/distribuição de estruturas tectônicas anteriores ao Neógeno, refutando assim a hipótese inicial do trabalho. / Cuestas are asymmetric landforms characterized by a steep slope along the plateau front and a gentle slope on its reverse, and they are interpreted as a relief formed by differential erosion of rocks. The São Pedro Ridge (Serra de São Pedro)/SP region, area with occurrence of juro-cretacic basalts (top of the ridge) and Triassic medium Cretaceous aeolian sandstone (scarp and glacis), is one of the most typical examples of the cuestas in the Paraná Basin. Although São Pedro Ridge is considered a cuesta, the geomorphological settings and the fluvial system (including the Lower Piracicaba River) of the area suggest a tectonic control on the landforms. Thus, the aim of this research was to verify a possible tectonic control on the São Pedro Ridge and Lower Piracicaba River landforms, emphasizing the Neotectonic influence. The hypothesis is that modern tectonics has a strong influence in the actual landforms. The results showed that the neotectonic activity in the study area is characterized mainly by sub-vertical strike-slip and normal faults WNW-ESE, WE, NW-SE and NE-SW, both with very small offsets and inconspicuous impact in the relief. The influence of the tectonic activity in the landforms is more intense in the fluvial system, controlling the relief dissection from joint planes, large fractures and faults, though modern tectonics is responsible for the control of the direction only of first and second order drainage channels. Neotectonics also controls the formation of triangular facets at the escarpment front of the São Pedro Ridge, faulting in quaternary fluvial deposits, anomalies in the longitudinal profiles of streams and changes in the direction of ridge lines and watercourses (river bends), as well as small block tilting which influences the formation and degradation of fluvial terraces of the Piracicaba right margin tributaries. These interpretations are coherent with the data set concerning the structures measured and materials characterized in the field, as well as with the information about the structural contour and geophysical data of the area. Despite the clear record of neotectonics in the São Pedro Ridge and Lower Piracicaba River region, the results demonstrated that the magnitude of the modern tectonic activity is small, and that the actual geomorphological configuration is more influenced by lithological factors, paleoclimates and the arrangement of sedimentary rock layers and pre-Neogene tectonic structures, thus refuting the initial hypothesis of this study.
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Avaliação histológica e microtomográfica comparativa entre o aloenxerto ósseo liofilizado e o aloenxerto ósseo congelado para preenchimento na elevação do assoalho de seio maxilar / Histological and microtomografic assessment between lyophilized and fresh-frozen allogenic bone grafts for sinus lifting : Randomized Controlled clinical TrialManzi, Marcello Roberto 15 September 2016 (has links)
O aloenxerto ósseo desmineralizado irradiado (ALD) e o aloenxerto ósseo congelado mineralizado (ACM) são alternativas ao osso autógeno para o aumento do rebordo ósseo alveolar. Individualmente, já foram testados quanto a eficiência, de certa forma, comparável aos autógenos e suas vantagens sobre eles. Entretanto, não há estudos padronizados comparando o desempenho clínico entre esses dois tipos de aloenxertos, quando utilizados em região de maxila atrófica para instalação e implantes. O objetivo deste estudo foi realizar um ensaio clínico randomizado controlado que envolve a elevação bilateral do seio maxilar empregando o osso alógeno liofilizado desmineralizado irradiado (ALD) ou o osso alógeno congelado mineralizado (ACM) e verificar comparativamente os desfechos clínicos para estabilidade de implantes, quantidade e qualidade de neoformação óssea. Dez pacientes foram submetidos a cirurgia de elevação do seio maxilar bilateral na qual foi utilizado um dos tipos de aloenxerto, de forma randômica em um dos lados. Seis a nove meses após o aumento do rebordo ósseo, no momento da instalação de implantes osseointegrados, foram obtidas amostras ósseas por meio de trefina de 2x10mm para análises microtomográficas e histológicas. A estabilidade dos implantes foi aferida por frequência de ressonância em dois momentos, imediato e após 6 meses da instalação dos implantes. Os resultados mostraram aumento do rebordo, radiograficamente detectável em todos os pacientes e grupos. Os implantes osseointegrados, inseridos em enxertos ACM, apresentaram melhor estabilidade primária, embora o acréscimo de estabilidade tenha sido mais significativo no ALD. As análises microtomográficas e histológicas revelaram mais formação óssea de melhor qualidade nos ALD do que nos ACM. Não houve resposta a corpo estranho para nenhum dos tipos de aloenxertos. Notou-se mais quantidade de material remanescente para ACM do que para ALD. Concluímos que os aloenxertos liofilizados desmineralizados irradiados (ALD) apresentaram melhor desempenho quanto aos parâmetros estudados. / Demineralized bone irradiated allograft (DFDBA) and fresh- frozen (FF) are alternative grafts to autogenous bone in alveolar ridge augmentation. Individually, these allografts have been tested for their efficiency, in a way comparable to autogenous, and so their advantages over autogenous grafts. However, there are no standardized clinical studies comparing the clinical and histological performance between these two allografts in atrophic maxilla bone augmentation for implants instalment. The aim of this study was to perform a randomized controlled clinical trial involving bilateral sinus floor elevation employing demineralized freeze-dried irradiated allograft (DFDBA) or fresh-frozen (FF) and to compare clinical and histological outcomes for stability of implants, quantity and quality of bone formation. Ten patients underwent bilateral maxillary sinus lifting surgery in which side was randomly used one of those allografts for alveolar ridge augmentation. Six to nine months after grafting, at the time of dental implants instalment, trephine 2x10mm bone core biopsies were obtained to micro computed tomographic and histological analyses. The stability of the implants was measured by resonance frequency in two stages, immediately and 6 months after implants installation. Results showed that there was an increase, radiographically detectable, in all patients and groups. The dental implants inserted in FF grafts showed better primary stability but implant stability, lately, increased significantly in DFDBA. Micro tomographic and histological analyses revealed that bone formation amount and quality was superior in DFDBA than in FF. There was no foreign body response for any of the allografts. There was a greater amount of persisting graft-materialin FF than in DFDBA. We conclude that demineralized freeze-dried irradiated allograft (DFDBA) presented a superior performance than mineralized FF.
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Tufas calcárias da Serra da Bodoquena, MS / \"Calcareous tufa from Bodoquena\'s Ridge, MS\"Oliveira, Emiliano Castro de 13 April 2009 (has links)
Aflorando abundantemente nas drenagens da Serra da Bodoquena, região sudoeste do Estado de Mato Grosso do Sul, os depósitos de tufas calcárias, descritos como a porção superior da Formação Xaraiés, representam o mais notável depósito do tipo no Brasil, devido à variedade de formas. Sendo a maior atração do pólo eco-turístico de Bonito, MS, as tufas calcárias apresentam-se sob formas de barragens, cachoeiras e depósitos de micritos inconsolidados, que por sua vez geram as piscinas naturais e quedas dágua tão procuradas pelos turistas. Mesmo com tamanha importância, tal rocha não havia recebido um estudo aprofundando, que contemplasse sedimentologia, estratigrafia e geomorfologia. Através de criteriosa revisão bibliográfica, trabalhos em campo e análises laboratoriais, pôde-se obter um panorama da Formação Xaraiés na Serra da Bodoquena. Nesta região, observa-se que a formação, assentada diretamente sobre os calcários e dolomitos do Grupo Corumbá, sendo composta por um nível basal de calcretes, de tipo pedogenético e freático, sobreposto por um pacote de tufas micríticas (micrito inconsolidado), com grande quantidade de gastrópodes, distribuídos amplamente e aflorando em todas as planícies da região. Por fim temos os afloramentos de tufas calcárias do tipo fitohermal, compondo barragens e cachoeiras nas drenagens locais. Acredita-se que a deposição dos micritos ocorreu em ambiente lacustre, o que permitiu um depósito amplo e homogêneo, que posteriormente, em clima úmido, serviu de área fonte, juntamente com os carbonatos do Grupo Corumbá, para a geração das tufas fitohermais. A correlação estratigráfica dos depósitos de tufas calcárias estudados apontam para dois períodos de clima semi-árido a árido no Holoceno, que permitiram a formação e a alteração (calcretização) de depósitos, refletido na base da Formação Xaraiés, e o período climático recente, úmido, a formação das tufas fitohermais, no topo da formação. A ocorrência de lentes micríticas no sul do Pantanal pode significar que esta região também esteve exposta às dinâmicas climáticas vistas na Serra da Bodoquena. Estas constatações demonstram a alta variação climática da região, representada por depósitos que são pequenos e frágeis, mas dotados de significados genéticos indubitáveis. / Crop out abundantly in the Bodoquena Ridge drainages, southwest of Mato Grosso do Sul (MS) state, deposits of calcareous tufa were described as the top portion of Xaraiés Formation, representing the most notable deposit of this type in Brazil, due to the variety of forms. As the greatest attractiveness of Bonito, MS, an eco-tourism center, the calcareous tufa were presented in form of dams, waterfalls and deposits of micritic sediments, which generate natural pools and waterfalls so looked by tourists. Even with such importance, this region had not received a deep study, with sedimentology, stratigraphy and geomorphology approach. An accurate bibliographic review was done, and with field work and laboratory analyzes this work could obtain a panorama of the Xaraiés Formation in Bodoquena Ridge. In this region, can be noted that Xaraiés Formation goes directly over the limestone and dolomite of the Corumbá Group, and were composed by a basal layer of pedogenetic/groundwater calcrete, superimposed by a package of micritic sediments (micritic tufa), with a large amount of gastropods, which were widely distributed, cropping out in all plains of the region. Finally, we have the occurrences of calcareous tufa, fitohermal type, drawing dams and waterfalls in the regional drainages. It has believed that the deposition of lacustrine micritic sediments have occurred in an environment which were enabled a broad and homogeneous deposits. Subsequently, in a moister climate these sediments served as a source area, together with the limestone of the Corumbá Group, for the generation of fitohermal tufa. The stratigraphic correlation of the studied calcareous tufa deposits point to two periods of semi-arid/arid climate in Holocene, which allowed the calcretization. Those were reflected on the bottom of the Xaraiés Formation, and a recent wet climatic period, represented by the fitohermal tufa at the top of the formation. The occurrence of micritic lens in the southern Pantanal may mean that this region has also been exposed to the weather dynamics viewed in the Bodoquena Ridge. These findings show the high variation of climate in this region, represented by deposits, which are small and fragile, but gifted with unquestionable genetic meanings.
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Variabilité géochimique du manteau à très petite échelle sous la dorsale Est-Pacifique (15°37' - 15°47'N) / Mantle geochemical variability at very small scale below the East Pacific Rise (15°37' - 15°47'N)Mougel, Bérengère 03 December 2013 (has links)
Le segment 16°N de la dorsale Est-Pacifique (EPR) interagit avec le point chaud des Mathématiciens (PCM). A partir de l’analyse géochimique de 120 échantillons de verres basaltiques prélevés par submersible Nautile (campagne à la mer PARISUB 2010) coulée par coulée, ce travail présente une étude à très petite échelle de l’hétérogénéité chimique du manteau sous quelques kilomètres de dorsale (15°37’N et 15°47’N). Les résultats obtenus témoignent d’une variabilité géochimique jamais observée à si petite échelle sous une dorsale. Le degré d’hétérogénéité du manteau dans cette zone est comparable à celui de l’ensemble de l’EPR. Cette diversité est le produit du mélange entre trois sources mantelliques principales, caractérisant l’influence et l’hétérogénéité du point chaud. La densité de l’échantillonnage offre une résolution spatiale en adéquation avec les données bathymétriques, ce qui a permis de coupler les deux approches et faire une reconstruction spatio-temporelle de l’évolution géochimique et morphologique du système EPR/PCM.Celle-ci commence il y a environ 600 ka par le gonflement du segment et un changement général dans la composition du manteau ambiant, suivi de deux sauts d’axe successifs en direction de la chaîne il y a 250 et 150 ka. Lors de cette phase de rapprochement de nouvelles signatures géochimiques émergent ponctuellement dans les MORB. Parmi elles,une signature relique de manteau appauvri régional, une autre d’hétérogénéité enrichie locale, et enfin celle de deux types d’hétérogénéités contenues dans la source du PCM.Cette dernière, n’apparaît dans les MORB qu’au cours des 100 dernières années autour de 15°44’N, et constitue une signature géochimique inédite pour des MORB. Ce nouveau composant a la particularité d’avoir du Pb très peu radiogénique ("Unradiogenic Lead Component", ULC) associé à des signatures isotopiques en Sr, Nd et Hf enrichies.Les compositions en éléments majeurs, traces et isotopes (Sr, Nd, Hf, Pb et He) suggèrent l’implication de matériel métagabbroique, ancien (>2Ga) à affinité continentale.La présence de sulfures dans la source permettrait d’expliquer le Pb peu radiogénique.Le recyclage dans le manteau supérieur de pyroxénites à sulfures, provenant de la partie profonde d’anciens arcs continentaux permettrait d’expliquer l’origine de ULC. Les basaltes ULC seraient donc les témoins volcaniques de la fusion de ce réservoir discret qui contribue à résoudre le paradoxe du Pb. / 120 Mid-Ocean-Ridge basaltic (MORB) glasses were collected on discrete lava flow (~200m sampling interval) during submersible dives along the East-Pacific-Rise (EPR), between 15°37’N and 14°47’N, precisely where the ridge intersects the Mathematicianshotspot track. The data display a geochemical variability that has never been observedalong a ridge at such a small spatial scale. The range of isotopic compositions along this 15 km segment is commensurable to that of the entire EPR. It can be accounted for by a mixture of three main components, representative of the hotspot heterogeneity.The dense sampling, along and across the ridge segment, matches the resolution of themicro-bathymetric data, which made the spatio-temporal reconstruction of the geochemical and morphological evolution of the EPR/Mathematician hotspot system possible.The latest starts 600 kya with the segment inflation and a global change in the ambient mantle composition, followed by two successive jumps of the ridge axis (250 and 150 kya) towards the seamounts chain. During this phase as the two systems are getting closer,new geochemical signatures emerge in MORB. Among them, relics of regional depleted mantle, small enriched local heterogeneities, and two types of heterogeneities belonging to the hotspot source. The last one become apparent only during the last 100 yearsaround 15°44’N, and constitutes a novel geochemical signature for MORB. This new component’s most noticeable property is its very unradiogenic Pb ("Unradiogenic Lead Component", ULC) associated with mostly enriched Sr, Nd and Hf isotopic signatures. Putted together, major, trace elements and isotopes (Sr, Nd, Hf, Pb and He) suggest anancient (>2Ga) lower continental metagabbroic origin for this material, while the involvement of sulfides is considered in order to explain the unradiogenic lead compositions. Overall, the preferred model for the formation of ULC is the recycling within the uppermantle of sulfide bearing pyroxenites coming from continental arc roots. ULC-influenced basalts represent magmatic witnesses of the melting of this cryptic reservoir that can contribute to solve the Pb paradox.
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Avaliação comparativa da Borda WALA em mandíbulas secas e modelos e da sua mensuração em radiografias oclusais e tomografias / A comparative assessment of the WALA ridge in dissected mandibles and cast models as well as its measurement in occlusal radiographies and tomographiesGastão Moura Neto 06 May 2010 (has links)
Introdução: a determinação da Borda WALA em modelos de gesso permitia defini-la como uma linha imaginária utilizada no planejamento, seguimento e finalização de casos clínicos. Procurou-se determinar a Borda WALA em modelos de gesso de pacientes ortodônticos, mandíbulas secas, radiografias oclusais e cortes tomográficos dos pacientes e mandíbulas respectivas. O objetivo foi detectar a viabilidade de mensurar e determinar, por um método reproduzível, a Borda WALA em radiografias oclusais e cortes tomográficos. Metodologia: foram utilizados modelos, radiografias oclusais e tomografias de feixe cônico de 12 pacientes ortodônticos, e 12 mandíbulas e suas respectivas radiografias oclusais e cortes tomográficos. As mensurações tomográficas foram realizadas, em todos os dentes, do ponto mais vestibular das raízes dentárias no nível cervical até a parte mais externa da cortical óssea vestibular. Nas mandíbulas secas e nos modelos, as medidas verticais partiam do ponto EV até a linha de grafite que determinou o ponto vestibular mais externo. Resultados: os arcos correspondentes à Borda WALA obtidos nos modelos de gesso e nas mandíbulas secas se equivaleram em sua forma, sendo um pouco menores, em sua dimensão, nos modelos. Os arcos obtidos a partir das mensurações realizadas em radiografias oclusais e cortes tomográficos se equivaleram, em sua forma, nos modelos e mandíbulas, com correlação fortemente positiva, detectada pelo Coeficiente de Correlação de Pearson. Conclusões: 1. a Borda WALA não representa uma estrutura anatômica, mas uma medida/anagrama/referência a ser mensurada e utilizada nos tratamentos ortodônticos e ortopédicos; 2. a Borda WALA não deve ser considerada uma linha imaginária, mas um arco a ser determinado por medidas que devem servir de parâmetro nas correções das alterações da oclusão e alinhamento dos dntes inferiores; 3. em seu contorno e forma, as medidas obtidas nos modelos e nas mandíbulas, assim como nas radiografias oclusais e tomografias de feixe cônico, se equivaleram estatisticamente. Nas radiografias oclusais dos pacientes, houve dificuldades técnicas para a obtenção de imagens que permitissem uma mensuração precisa na determinação da Borda WALA. Nos cortes tomográficos, as medidas realizadas para determinação da Borda WALA reproduziram, com coeficiente de correlação fortemente positivo, a dimensão e a forma obtidas em medidas nos modelos de gesso e nas mandíbulas secas. Em suma, a determinação da Borda WALA a partir de cortes tomográficos transversais no nível cervical dos dentes inferiores é viável, pois a dimensão e a forma do arco obtido se equivalem estatisticamente ao arco obtido pelas medidas realizadas em modelos de gesso e mandíbulas secas. / Introduction: The WALA ridge is an imaginary line determined in cast models and used as reference for orthodontic treatment planning, execution and finalization. In the following study, the WALA ridge was defined in cast models of orthodontic patients, dissected mandibles, occlusal radiographies and tomographic slices of patients and respective mandibles aiming to find a reproducible method for determining the WALA ridge in occlusal radiographies and tomographic slices. Methodology: The sample comprised 12 cast models, occlusal radiographies and cone beam tomographies of orthodontic patients and 12 dissected mandibles, their respective occlusal radiographies and tomographic slices. Tomographic measurements were made in all teeth from the most buccal point of dental roots on their cervical level until the most external and anterior cortical line of bone. Vertical measurements on dissected mandibles and cast models were taken from FA point until the pencil line that determined the most external edge of bone around mandibular teeth. Results: The arches corresponding to the WALA ridge obtained from cast models and dissected mandibles were equivalent in form but a little smaller in size for cast models. The arches obtained from occlusal radiographies and tomographic slices were equivalent in form to the ones obtained from models and dissected mandibles, with a high positive correlation of proportion statistically confirmed by Pearsons coefficient. Conclusion: 1. The WALA ridge is not an anatomical structure, but a measurement/anagram/reference to be measured and used during orthodontic and orthopedic treatment. 2. The WALA ridge should not be considered an imaginary line, but an arch to be determined by measurements and used as parameter when correcting the occlusion of misalignment of inferior teeth; 3. The measurements obtained from models and dissected mandibles, as well as from occlusal radiographies and cone beam tomographies were equivalent in shape and form. Obtaining the WALA ridge from occlusal radiographies in patients involve technical difficulties to acquire a good image for precise measurement. Tomographic measurements to determine the WALA ridge were reproducible, with a high positive correlation coefficient to the dimension and form obtained from cast models and dissected mandible measurements. To sum up, determining the WALA ridge from tomographic transversal slices on the cervical level of inferior teeth is viable, since the dimension and arch form are statistically equivalent to the arch form obtained from cast models and dissected mandibles.
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Nameless wonders and dumb despair: rhetorics of silence in mid-nineteenth-century U.S. poetry and cultureBorchert, Nick 01 August 2017 (has links)
Taking a cue from the occasional reticence of the often-exuberant American Romantic poetics, this project tracks what I call “rhetorics of silence” in verse: those moments where words are declared to be inadequate, impertinent, unavailable, unintelligible or otherwise unsuitable for a task that the poet has proposed. In this respect, the term “silence” functions here as a broad metaphor encompassing a number of meta-linguistic or meta-poetic gestures aimed at highlighting the shortcomings of knowledge and representation.
Whereas earlier critics have noticed these silences in haphazard ways, this project looks toward a systematic account of why and when nineteenth-century poets rely on gestures to the space beyond language. This intervention is especially useful for reading the seminal American poets Walt Whitman and Emily Dickinson. Because Whitman seems celebratory and Dickinson doleful, it has often been difficult to offer productive readings of the two in tandem. Where Whitman does resemble Dickinson, it is often thought to be in his poems that abandon or despair of his project for a democratic poetics. By contrast, working through the lyric and political verse of the lesser-known poetry of John Rollin Ridge, this project reads visionary and despairing silences as alike rhetorical gestures aimed at highlighting the common humanity of the poet and the reader. “Silence” is therefore an outgrowth of American ideology, albeit one that frequently allows poets to expand and query that ideology in ways that are not possible in the many corresponding but often blither deployments of rhetorical silence in the culture at large.
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