No description available.

No description available.

Notre objectif a été d'analyser l'influence de la variabilité spatio-temporelle de la réflectance des cônes sur le comptage des cônes par imagerie à haute résolution par optique adaptative plein champ, et de proposer des méthodes pour pallier ces difficultés. La première partie des travaux porte sur l'étude de la variabilité temporelle des cônes. Nous avons confirmé la présence d'un phénomène de scintillement des cônes à une fréquence au moins égale à celle de notre système d'acquisition. Nous avons proposé une procédure d'analyse d'images incluant restauration par déconvolution myope, recalage rigide, fusion d'images pour la construction de cartographies de cônes. Nous avons montré que dans le cas des sujets sains, la procédure de fusion d'image permet de rapprocher la mesure de la densité des cônes des références histologiques. La directionalité de la réflectance des cônes est appelée effet Stiles-Crawford optique. Nous en avons identifié une nouvelle manifestation clinique, à travers une étude portant sur l'analyse d'images d'optique adaptative en périphérie de la rétine. Nous avons montré, à travers l'alternance des mosaïques positive/négative, que la réflectance des cônes peut devenir inférieure à celle des bâtonnets. La comparaison avec les données de la tomographie de cohérence optique a montré une forte corrélation de cette commutation avec la couche des segments externes des cônes. Nous avons proposé une procédure d'intégration de la variabilité spatiale pour la construction des cartographies. Cette procédure a été évaluée sur des sujets sains et pathologiques et a montré un gain significatif (en termes de dénombrement des cônes) chez les cas pathologiques. / Our objective was to analyze the importance of spatial and temporal variability of the reflectance of cones in counting for adaptive optics high resolution imaging, and propose ways to overcome these difficulties.The first part of the work focuses on the study of the temporal variability of cones. We confirmed the presence of a scintillation phenomenon at a frequency at least equal to that of our acquisition system. We have proposed an image analysis process including restoration by deconvolution, rigid registration, and image fusion for cone mapping. To validate this approach, we conducted a validation test for two deconvolution methods. We have shown that in the case of healthy subjects, the image fusion procedure to bring the measurement of cone density and histological references. The angular variation of cone reflectance is called optical Stiles-Crawford effect. We have identified a new clinical manifestation of this phenomenon, through a study on the analysis of adaptive optics images periphery). We have shown, through the alternation of the positive / negative mosaics, that the reflectance of the cones may become lower than that of rods. Comparison with the data of the optical coherence tomography showed a strong correlation of the switching with the outer segment layer. We then proposed a procedure of integration of spatial variability for cone mapping. This procedure was evaluated in healthy and diseased subjects and showed a significant gain (in terms of cone enumeration) in pathological cases.

This study is an analytical examination of a stylistic anomaly observed among Middleport Iroquoian village sites (dating c. A.D. 1300-1450) located near Crawford Lake in southcentral Ontario, Canada. The anomaly is characterized by differing percentages of two forms of ceramic smoking pipes from closely spaced, contemporaneous village sites. This distinction occurs throughout southern Ontario, but is particularly pronounced in the Crawford Lake area. In order to develop and test a model to explain this anomaly, an approach employing a hierarchy of inference, including formal, spatial, temporal, economic, social, and cultural levels, is proposed. This is applied to an analysis of pottery and smoking pipes from eight Middleport sites. The key elements of the explanation are: (1) the two styles represent two distinct prehistoric communities; (2) these communities competed with each other for limited resources; and (3) they symbolized this competition through differences in pipe styles. This conclusion indicates that both the material culture and social relations among Middleport communities may be more complex than has previously been inferred.

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This thesis explores Ralston Crawford’s canvases painted after witnessing the events of Operation Crossroads at the Bikini Atoll in 1946. Commissioned by Fortune, the artist provides the viewer with a unique and captivating view of the destruction wrought by atomic weaponry. Through a careful look at Crawford’s relationship with Fortune, Edith Halpert’s Downtown Gallery, and Crawford’s artistic contemporaries, this thesis positions the paintings within the art historical and cultural context of the mid-twentieth century and asserts their importance to the history of the Atomic Age. The thesis traces Crawford’s artistic development and his use of an Americanized Cubist language. In addition, the thesis looks closely at the rich cultural fabric of the postwar era and evaluates Crawford’s position in the American Art scene. / text

This dissertation examines the theological writing and preaching of Robert Boyte Crawford Howell, Southern Baptist pastor, editor, author, and denominational leader in the mid-nineteenth century. It argues that Howell promoted Baptist denominational participation in what many historians call "the benevolent empire" by demonstrating in his soteriology, ecclesiology, and eschatology the consistent connection between divine sovereignty and human responsibility in God's mission to the world. The dissertation demonstrates that Howell responded to the challenges brought to the burgeoning missions and benevolent movement among Baptists, particularly from antimission Baptists, populist Arminian, the Restoration Movement, pedobaptists, and Landmarkers, by constructing a theological foundation for the church's mission built upon a carefully integrated view of divine sovereignty and human responsibility. Chapter one outlines the rise of the missions and benevolent movement among American denominations in the nineteenth century, known by historians as "the benevolent empire," giving attention to the beginning of Baptist denominational work. The chapter further describes Howell's ministerial labors on behalf of missions and benevolence throughout his ministry and the desire he articulated to provide a solid theological foundation for the movement. The dissertation is organized according to systematic-theological categories in order to demonstrate the integration Howell endeavored to achieve in each doctrine in the midst of pressures from various opponents. Chapter two analyzes Howell's view of the divine decrees, providing analysis of his position on election and reprobation. Chapter three analyzes Howell's views on human depravity and the role of the Holy Spirit in the regeneration of the soul and revival in the church. Chapter four analyzes Howell's view of Christ's work on the cross, focusing on the covenant of redemption, the nature and extent of the atonement, justification, faith, repentance, sanctification, and perseverance. Chapter five sets forth Howell's convictions about God's mission for the church, the polity that God had ordained for the accomplishment of that mission, and the proper perspective on cooperation with other believers for the sake of missions. Chapter six explains Howell's postmillennial convictions and the impetus his missions and benevolent work received from this doctrine. Chapter seven contains a summary, conclusion, and prospects for future research. / This item is only available to students and faculty of the Southern Baptist Theological Seminary. If you are not associated with SBTS, this dissertation may be purchased from <a href="http://disexpress.umi.com/dxweb">http://disexpress.umi.com/dxweb</a> or downloaded through ProQuest's Dissertation and Theses database if your institution subscribes to that service.

Thesis (Ed.D.)--Teachers College, Columbia University, 1989. / Typescript; issued also on microfilm. Sponsor: Lenore M. Pogonowski. Dissertation Committee: Harold F. Abeles. Bibliography: leaves 322-324.

Cell biological exposure studies in magnetic resonance imaging (MRI) environment, where a complex mixture of strong magnetic fields are present, have attracted considerable interest in recent years. The outcome of such studies might depend strongly on the conditions, for example exposure parameters and spatial variations of exposure. The aim of this thesis has been to give a detailed description of how the radio frequency (RF) magnetic field varies with position and sequence choice within an MRI bore from a patient perspective and to highlight the need of better consistency in future research. Method: A straightforward theoretical description on the contribution to the RF magnetic field from a birdcage coil is given. A one dimensional coaxial loop antenna has been used as a probe to measure spatial variations of the RF magnetic field in a 1.5T MRI scanner. An exposure matrix containing RF magnetic field strength (H1-field) amplitudes in three dimensions was constructed and used to study several clinical protocols and sequences. A qualified correspondence measurement was also made on a 3T MRI scanner. Results: Around isocenter, for a common field-of-view (FOV), changes in exposure conditions were small; however, rapid changes of exposure conditions occurred upon approaching the end rings. The dominating H1-field component switched from lying in the xy-plane to pointing the z-direction and was roughly 3 times larger than in isocenter. Practical difficulties indicate even larger differences at positions not measurable with the equipment at hand. The strongest H1-field component was 32.6 A/m at position (x,y,z)=(-24,8,24) cm from the isocenter. Conclusions: Machine parameters such as repetition time, echo time and flip angle have little to do with actual exposure. Specic absorption rate (SAR) values correlated well with the square of measured root-mean-square (RMS) values of the magnetic field (B1,RMS) but not with peak values of the magnetic field (B1,peak), indicating that peak values are not unlikely to be part of compromising factors in previous contradictory exposure research on genotoxicity. Furthermore exposure conditions depend strongly on position and unfavorable situations may occur in the periphery of the birdcage coil. Potentially elevated risks for conducting surfaces, for example arms or external fixations, in the proximity of the end rings, are proposed. Aside from spatial variation consideration on which type of geometry exposed cell-biological samples are placed in should be held since eddy currents, hot-spots and proper SAR depend on geometry. Conditions may vary considerably between in-vitro, ex-vivo and in-vivo studies since geometries of test tubes, petri dishes and humans differ.

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 224-250.