32 resultados para Laser Science
Resumo:
Retinal imaging with a confocal scaning laser Ophthalmoscope (cSLO) involves scanning a small laser beam over the retina and constructing an image from the reflected light. By applying the confocal principle, tomographic images can be produced by measuring a sequence of slices at different depths. However, the thickness of such slices, when compared with the retinal thickness, is too large to give useful 3D retinal images, if no processing is done. In this work, a prototype cSLO was modified in terms hardware and software to give the ability of doing the tomographic measurements with the maximum theoretical axial resolution possible. A model eye was built to test the performance of the system. A novel algorithm has been developed which fits a double Gaussian curve to the axial intensity profiles generated from a stack of images slices. The underlying assumption is that the laser light has mainly been reflected by two structures in the retina, the internal limiting membrane and the retinal pigment epithelium. From the fitted curve topographic images and novel thickness images of the retina can be generated. Deconvolution algorithms have also been developed to improve the axial resolution of the system, using a theoretically predicted cSLO point spread function. The technique was evaluated using measurements made on a model eye, four normal eyes and seven eyes containing retinal pathology. The reproducibility, accuracy and physiological measurements obtained, were compared with available published data, and showed good agreement. The difference in the measurements when using a double rather than a single Gaussian model was also analysed.
Resumo:
Applied Physics B Lasers and Optics, vol.71
Resumo:
In Portugal, especially starting in the 1970s, women’s studies had implications on the emergency of the concept of gender and the feminist criticism to the prevailing models about differences between sexes. Until then, women had been absent from scientific research both as subject and as object. Feminism brought more reflexivity to the scientific thinking. After the 25th of April 1974, because of the consequent political openness, several innovating themes of research emerged, together with new concepts and fields of study. However, as far as gender and science relationship is concerned, such studies especially concentrate on higher education institutions. The feminist thinking seems to have two main objectives: to give women visibility, on the one hand, and to denunciate men’s domain in the several fields of knowledge. In 1977, the “Feminine Commission” is created and since then it has been publishing studies on women’s condition and contributing to the enhancement of the reflection of female condition at all levels. In the 1980s, the growing feminisation of tertiary education (both of students and academics), favoured the development of women’s studies, especially on their condition within universities with a special focus on the glass ceiling, despite the lack of statistical data by gender, thus making difficult the analysis of women integration in several sectors, namely in educational and scientific research activities. Other agglutinating themes are family, social and legal condition, work, education, and feminine intervention on political and social movements. In the 1990s, Women Studies are institutionalised in the academic context with the creation of the first Master in Women Studies in the Universidade Aberta (Open University), in Lisbon. In 1999, the first Portuguese journal of women studies is created – “Faces de Eva”. Seminars, conferences, thesis, journals, and projects on women’s studies are more and more common. However, results and publications are not so divulgated as they should be, because of lack of comprehensive and coordinated databases. 2. Analysis by topics 2.1. Horizontal and vertical segregation Research questions It is one of the main areas of research in Portugal. Essentially two issues have been considered: - The analysis of vertical gender segregation in educational and professional fields, having reflexes on women professional career progression with special attention to men’s power in control positions and the glass ceiling. - The analysis of horizontal segregation, special in higher education (teaching and research) where women have less visibility than men, and the under-representation of women in technology and technological careers. Research in this area mainly focuses on description, showing the under-representation of women in certain scientific areas and senior positions. Nevertheless, the studies that analyze horizontal segregation in the field of education adopt a more analytical approach which focuses on the analysis of the mechanisms of reproduction of gender stereotypes, especially socialisation, influencing educational and career choices. 1
Resumo:
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Mecânica
Resumo:
From an early age Henri Tintant was conforted with the problematic relationships between Science and Faith. After a traditional religious education, he took responsabilities within groups of teenagers and adults through scouting and the J. E. C. (an organisation of catholic students). In 1940 he was at Montpellier distributing unauthorised leaflets defending religious faith. But more significant is his intellectual contribution. He was an active and inspiring member of several workshops and in one in particumar initiated by the Catholic University of Lyon entitled : "From Naturalist to Theologians" where he would start a very fruitful and compelling intellectual collaboration with Father Gustave Martelet a jesuit theologian and a strong supporter of a permanent dialog with the scientists. Throughout the years they will gradually come to the conclusion of a necessary synergy between the scientific and the theologic approach when dealing with the mystery of religious faith . Even in the last months of his life, Henri Tintant was writing to his friendon the subject, with the same profound religious faith that brought him the serenity and the open mindness he has showed throughout his teaching and scientific career. His legacy will remain in two of his last thoughts: "Almost 50 years of scientific research have brought me a lot of pleausures and satisfactions but no answer to the essential questions. In my personal case, science and researching have not driven me away from my religious faith, on the contrary the helped me in my awareness of its utmost necessity". "Faithful to my religious belief, I am convinced that with the death, the inevitable human destiny, not everything disapears completely but another form of live, unimaginable for our limited minds, emerges, bearing in itself the perfect realization of all our hopes and desires".
Resumo:
Thesis presented at the Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, to obtain a Master degree in Conservation and Restoration,Specialization in Textiles
Resumo:
Proceedings of the Chemistry and Conservation Science
Resumo:
Proceedings of the First International Conference on Coastal Conservation and Management in the Atlantic and Mediterranean, p. 193-200
Optimização da focagem de feixes laser em tecidos biológicos: desenvolvimento de um simulador óptico
Resumo:
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Biomédica
Resumo:
A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Information Systems.
Resumo:
Dissertação de Mestrado em Conservação e Restauro - Metais
Resumo:
Thesis submitted to the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia, for the degree of Doctor of Philosophy in Biochemistry
Resumo:
Thesis for the Degree of Master of Science in Bioorganic Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia
Resumo:
Dissertação para obtenção do Grau de Mestre em Engenharia Física
Resumo:
Dissertação para obtencão do grau de Mestrado em Arte e Ciência do Vidro