Study of nuclear reactions relevant for astrophysics by Micro-AMS

Disserta����o para obten����o do Grau de Doutor em F��sica

Experimental study of proton induced nuclear reactions in 6,7 Li

This work presents the results of the experimental study of proton induced nuclear reactions in lithium, namely the 7Li(p,��) 4He, 6Li(p,��) 3He and 7Li(p,p)7Li reactions. The amount of 7Li and 6Li identified as primordial and observed in very old stars of the Milky Way galactic halo strongly deviates from the predictions of primordial nucleosynthesis and stellar evolution models which depend, among other factors, on the cross sections of reactions like 7Li(p,��) 4He and 6Li(p,��) 3He. These discrepancies have triggered a large amount of research in the fields of stellar evolution, cosmology, pre-galactic evolution and low energy nuclear reactions. Focusing on nuclear reactions, this work has measured the 7Li(p,��) 4He and 6Li(p,��) 3He reactions cross sections (expressed in terms of the astrophysical S -factor) with higher accuracy, and the electron screening effects in these reactions for different environments (insulators and metallic targets). The 7Li(p,��) 4He angular distributions were also measured. These measurementstook place in two laboratory facilities, in the framework of the LUNA (Laboratory for Undergroud Nuclear Astrophysics) international collaboration, namely the Laboratorio �� de Feixe de Ioes �� in ITN (Instituto Tecnologico �� e Nuclear) Sacavem, �� Portugal, and the Dynamitron-TandemLaboratorium in Ruhr-Universitat�� Bochum, Germany. The ITN target chamber was modified to measure these nuclear reactions, with the design and construction of new components, the addition of one turbomolecular pump and a cold finger. The 7Li(p,��) 4He and 6Li(p,��) 3He reactions were measured concurrently with seven and four targets, respectively. These targets were produced in order to obtain adequate and stable lithium depth profiles. In metallic environments, the measured electron screening potential energies are much higher than the predictions of atomic-physics models. The Debye screening model applied to the metallic conduction electrons is able to explain these high values. It is a simple model, but also very robust. Concerning primordial nucleosynthesis and stellar evolution models, these results are very important as they show that laboratory measurements are well controlled, and the model inputs from these cross sections are therefore correct. In this work the 7Li(p,p)7Li differential cross section was also measured, which is useful to describe the 7Li(p,��) 4He entrance channel.

An overview of the higher level classification of Pucciniomycotina based on combined analyses of nuclear large and small subunit rDNA sequences

Mycologia, Vol. 98, n��6

Estudos estruturais em ferredoxinas por resson��ncia magn��tica nuclear

Disserta����o apresentada para obten����o do Grau de Doutor em Qu��mica, especialidade Qu��mica Inorg��nica, pela Universidade Nova de Lisboa, Faculdade de Ci��ncias e Tecnologia

Meta-analysis of gender and science research - Country report - Portugal

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

O debate estrat��gico nuclear nos EUA (1945-2010): tend��ncias e evolu����o

Disserta����o apresentada para cumprimento dos requisitos necess��rios �� obten����o do grau de Mestre em Ci��ncia Pol��tica e Rela����es Internacionais,

Henri Tintant face au probl��me "Science et Foi"

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".

The discovery of three lost ���Salting��� carpets: science as a tool for revealing their history

Thesis presented at the Faculdade de Ci��ncias e Tecnologia, Universidade Nova de Lisboa, to obtain a Master degree in Conservation and Restoration,Specialization in Textiles

Static laws in dynamic environments (bridging science to legislation)

Proceedings of the First International Conference on Coastal Conservation and Management in the Atlantic and Mediterranean, p. 193-200

Artificial Intelligence in geospatial analysis: applications of self-organizing maps in the context of geographic information science.

A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Information Systems.

Development of cyclodextrin-hydrogel polymeric systems in scCO2 for drug delivery

Thesis for the Degree of Master of Science in Bioorganic Universidade Nova de Lisboa, Faculdade de Ci��ncias e Tecnologia

A reac����o nuclear 23Na(p,p�����)23Na - optimiza����o da Linha de PIGE do acelerador Tandem de 3 MV da UFA-ITN

Disserta����o para obten����o do Grau de Mestre em Engenharia F��sica

Planning, operations and data handling of planetary science missions

Disserta����o para obten����o do Grau de Mestre em Engenharia F��sica

Velas i��adas: navigating emotion in a sea of science

Disserta����o para obtenc��o do grau de Mestrado em Arte e Ci��ncia do Vidro

Guerra (in)justa, ci��ncia (im)pura

Se h�� conjun����o fatal, �� entre guerra e ci��ncia, em nome dos imperativos da defesa nacional. �� hoje um dado adquirido que a Segunda Guerra Mundial foi t��o extraordinariamente produtiva no campo cient��fico, quanto inumana, da biomedicina criminosa nazi �� f��sica at��mica norte-americana. Muitas das aplica����es t��cnicas com que actualmente convivemos de forma pac��fica, na maior candura e na maior inoc��ncia, tiveram origem em investiga����o fundamental e aplicada desenvolvida no decurso da Segunda Guerra Mundial por ambas as partes em conflito. De resto, apudenda origo da Big Science que hoje nos �� t��o familiar, h�� que encontr��-la nos grandes projectos de investiga����o cient��fica empreendida e apoiada pelos Estados beligerantes no decurso do conflito mundial e que a Guerra Fria mais n��o faz do que prolongar. Somos herdeiros de uma ci��ncia prosseguida em nome da raz��o de Estado e dos superiores interesses da defesa nacional, inteiramente subordinada a fins b��licos, invocados quer pelos Aliados, quer pelo Eixo. Conhecem- se abundantes exemplos disso, do radar aos antibi��ticos e �� energia nuclear, desenvolvidos do lado Aliado. Menos conhecidos, mas decerto que incomparavelmente mais inquietantes, s��o alguns frutos da experimenta����o m��dica levada a cabo no mundo concentracion��rio nazi, cujos resultados foram aproveitados pela ci��ncia posterior.