1,721,073 research outputs found
Influencia do campo de visao triangular convexo na expressao do artefato de alteraçao volumétrica em tomografia computadorizada de feixe conico: Influence of the convex triangular field of view on the expression of volumetric alteration artefact in cone-beam computed tomography
No full textUCR::Rectoría::Oficina de Asuntos Internacionales y Cooperación Externa (OAICE
Impacto do campo de visao triangular convexo de tomografía computarizada de feixe conico na expressao de artefatos associados ao endurecimiento de feixe de raios X e na dose de radiacao: Impact of the convex triangular field of view of cone-beam computed tomography on beam hardening-related artifacts and radiation dose
No full textTese (doutor em radiologia odontológica)-- Universidade Estadual de Campinas. Facultade de Odontologia. Área de Radiologia OdontológicaObjetivo: Avaliar o efeito do campo de visão (FOV) triangular convexo na distorção da imagem de materiais metálicos, na magnitude dos artefatos relacionados ao endurecimento do feixe de raios X, e na dose de radiação usando dois aparelhos de tomografia computadorizada de feixe cônico (TCFC). Métodos: A fase experimental da presente tese foi desenvolvida em três etapas: 1. Avaliação da distorção; 2. Avaliação da magnitude dos artefatos e 3. Avaliação dosimétrica. Para a avaliação da distorção, cilindros de cobalto-crômio, guta-percha, titânio e zircônia de dimensões conhecidas foram colocados individualmente em um fantoma de polimetilmetacrilato (PMM). Foram adquiridos 192 volumes de TCFC utilizando os FOVs triangulares convexos (100x80mm) e cilíndricos (80x80mm) dos aparelhos Veraviewepocs R100 (R100) e Veraview X800 (X800). Para determinar a distorção da forma do objeto, dois radiologistas orais e maxilofaciais (ROMFs) mediram as dimensões tomográficas horizontais e verticais dos cilindros usando o software HorosTM. Para avaliação subjetiva da distorção, nove OMFRs visualizaram vídeos de 10 segundos de imagens axiais de TCFC para identificar a forma axial de cada cilindro como triangular convexa, intermediária ou circular. Para avaliação da magnitude dos artefatos, cilindros de amálgama, cobalto-crômio, titânio e zircônia foram colocados individualmente no simulador de PMM e digitalizados usando os FOVs triangulares convexos e cilíndricos do X800, totalizando 60 exames de TCFC. Um ROMF desenhou 15 regiões de interesse (ROIs) de 2x2mm, distribuídas a 0,5, 1,0 e 1,5cm do centro de cada cilindro, usando o software Image J. A média e o desvio-padrão do valor dos tons de cinza de cada ROI foram calculados para cada distância e subtraídos dos valores de uma ROI controle para calcular a média da diferença (MDVC) e o desviopadrão do valor dos tons de cinza (DPVC). Para dosimetria, dosímetros...Inglés: Aim: To assess the effect of the convex triangular field of view (FOV) on shape distortion of metallic objects and magnitude of artifacts related to the X-ray beam hardening, as in radiation dose using two cone-beam computed tomography (CBCT) devices. Methods: The thesis experimental phase consisted of three stages: distortion assessment, artifact magnitude assessment, and dosimetry assessment.For the distortion assessment, cylinders of chromium-cobalt, gutta-percha, titanium, and zirconia of known dimensions were individually placed in a polymethylmethacrylate (PMM) phantom. 192 CBCT scans were acquired using the convex triangular (100 mm diameter x 80 mm height) and cylindrical (80x80 mm) FOVs of Veraviewepocs R100 (R100) and Veraview X800 (X800) devices (J. Morita, Kyoto, Japan). Two oral and maxillofacial radiologists (OMFRs) measured the horizontal and vertical dimensions of the reconstructed cylinders using HorosTM v. 3.3.6 software (Nimble Co LLC Purview, Annapolis, MD)to assess shape distortion. For subjective assessment of shape distortion, nine OMFRs viewed 10 - second videos of CBCT scans and identified the axial shape of each cylinder as convex triangular, intermediary, or circular. For the assessment of the magnitude of the artifacts, cylinders of amalgam, chromium-cobalt, titanium, and zirconia were individually placed in the PMM phantom and scanned using the convex triangular and cylindrical FOVs of the X800 totalling 60 CBCT scans. An OMFR designed 15 square regions of interest (ROIs) of 2x2 mm distributed at 0.5, 1.0, and 1.5cm from the center ofeach cylinder using Image J software (National Institutes of Health, Maryland, MD). Mean grey value and standard deviation of each ROI were averaged for each distance and subtracted from the values of a control ROI to calculate the grey value mean difference ( GVMD) and grey value standard deviation (GVSD). For dosimetry, optically stimulated luminescence dosimeters were placed in an...UCR::Rectoría::Oficina de Asuntos Internacionales y Cooperación Externa (OAICE
Impacto do campo de visao triangular convexo de tomografía computarizada de feixe conico na expressao de artefatos associados ao endurecimiento de feixe de raios X e na dose de radiacao: Impact of the convex triangular field of view of cone-beam computed tomography on beam hardening-related artifacts and radiation dose
No full textUCR::Rectoría::Oficina de Asuntos Internacionales y Cooperación Externa (OAICE
Estudo comparativo cefalometrico radiografico dos padrões de crescimento facial em pacientes portadores de fibromatose gengival hereditaria e pacientes portadores de oclusão normal
Full text linkOrientador : Frab Norberto BoscoloDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A presente pesquisa teve o propósito de estudar os padroes de rescimento facial em pacientes portadores de Fibromatose Gencival Hereditária,comparando-os com os de pacient.es portadores de Oclusão Normal. Para isso foram utilizadas radiografias cefalométricas. Os resultados evidenciáram que, quanto aos padrões de crescimento :facial,os pacientes portadores de Fibromatose Gengival Hereditária apresentaram um crescimento facial hiperdivergente e quando comparados com os padrões de crescimento facial de pacientes portadores de Oclusão Normal. Com relação às medidas üneares aqui estudadas, estas
apresentaaram-se aumentaadas com o decorrer da idade dos pacientes. Quando analisadas as medidas ancularoes, estas se apresentaram maiores nos pacient.es portadores de F.G.H., com exceção do ânculo SNB. Os resultados mostraram ainda que os pacientes do sexo masculino apresentaram médias gerais maior-es que as do sexo f'eminino, com exceção das variáveis NS.GNc e ANBAbstract: Patterns of facial crowt.h oC pat.lent.s wit.h heredit.ary cinci val Cibrornat.osis were compared wi t.h t.hose of indi viduals wi t.h normal occlusion usinc cepha1omet.rics roent.cenocraphics t.echincs. The result.s showed . t.hat. t.he values were hfcher I in males t.han in Cernales, except. t.he variables NS-GNc and ANB , and t.hat. t.he linear measures increased wi t.h t.he ace oC t.he pat.ient.. Ancular measupes were hicher in pat.ient.s wit.h hered:1- t.ary cincival Cibrornat.osis except. t.he SNB anele. Pat.t.erns of Cadal crowt.h in pat.ient.s wit.h heredit.ary Cincival f'ibrornat.osis were hyperdi vercent. in relat.ion t.o t.he dat.a obt.ained Crom pat.ient.s wit.h normal occlusionMestradoMestre em Odontologi
Estudo do posicionamento do condilo e do disco articular correlacionado com a sintomatologia das desordens temporomandibulares por meio de imagens por ressonancia magnetica
No full textTese (livre-docencia) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O propósito deste trabalho foi estudar o relacionamento entre o posicionamento do côndilo na fossa mandibular, a excursão condilar em boca aberta e o posicionamento do disco articular nas amostras sintomáticas e assintomáticas. A correlação do exame clínico com os achados nos exames por ressonância magnética. A presença da banda inferior da zona bilaminar também foi estuda. A amostra foi composta por 40 voluntários assintomáticos e 37 pacientes portadores de sintomatologia de deslocamento de disco com redução. Os resultados mostraram que o posicionamento do côndilo em boca fechada e a excursão condilar em boca aberta não podem ser usados sozinho no diagnóstico das disfunções temporomandibulares. As imagens coronais obtidas pelo novo modo de planejamento proporcionou uma melhor visualização do disco articular, principalmente no pólo lateral. Quanto ao disco articular, o mesmo estava em posição normal bilateralmente em 82,5% dos voluntários assintomáticos e estava deslocado bilateralmente em 62,2% dos pacientes sintomáticos. 58,3% das ATMs contra-laterais assintomáticas eram portadoras de deslocamento de disco. O exame clínico mostrou ser uma ferramenta útil somente quando aplicado para o diagnóstico de ATMs normais. Quando aplicado no diagnóstico de desordens internas, uma grande quantidade de diagnóstico falso-positivo foi encontradaAbstract: The purpose of this work was study the relationship among the positioning of the condyle in the mandibular fossa, the condylar translation and disk position in the symptomatic and asymptomatic groups. The correlation of the clinical exam with the magnetic resonance imaging was studied. The visualization of the inferior band of the bilaminar zone also was studied. The sample was composed by 40 asymptomatic volunteers and 37 patient with disk displacement with reduction. The results showed that the position of the condyle in close mouth and the condylar translation cannot be used alone in the diagnosis of the temporomandibular disorders. The new coronal oblique images provided a better visualization of the disk, mainly in the lateral pole. The disk was viewed bilaterally in normal position in 82,5% of the asymptomatic volunteers and it was displacement bilaterally in 62,2% of the symptomatic patients. 58,3% of the contralateral asymptomatic TMJs were disk displacement. The clinical examination showed to be only useful when applied for diagnosis of normal TMJs. When applied for diagnosis of internal displacement, a great amount of false-positive diagnosis was foundLivre DocênciaLivre Docente em Radiologia Odontologic
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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