From Bonn with love: West German interests in the 1975 nuclear agreement with Brazil

The 1975 nuclear cooperation agreement between Brazil and West Germany had a considerable impact on the mid-Cold War nuclear non-proliferation regime. This article analyses Bonn's interests in that agreement, as well as the negotiation process leading to it and third-party pressures on both countries. It also covers the follow-up negotiations with Urenco partners for a safeguards agreement. Based on extensive archival research and secondary literature, the author delineates three main West German interests in concluding the 'Brazilian Atomic-Deal': (1) strengthening the ruling socio-liberal coalition; (2) boosting the West German nuclear industry; and (3) making viable the jet-nozzle technology

Electronics design and implementation of a compressed sensing instrument for astronomy

Tese de mestrado integrado em Engenharia Física, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2015Aquisição comprimida (também conhecida como compressed sensing) é um novo conceito que tem atraído muita investigação nos dias de hoje. Esta teoria afirma que só é necessário adquirir um pequeno número de medidas para reconstruir uma imagem ou qualquer outro sinal. De outra forma, a aquisição comprimida permite que a compressão possa ser realizada durante a própria obtenção da imagem. Uma característica notável da aquisição comprimida é que os sinais podem ser reconstruídos com taxas de amostragens mais baixas que as impostas pela teoria da amostragem de Shannon-Nyquist. Esta teoria tem sido cada vez mais desenvolvida, tanto nos campos da matemática computacional como do processamento de sinal. Dado que hoje em dia temos que armazenar cada vez mais informação, têm começado a aparecer aplicações onde a compressão de dados é um requisito fundamental. Uma das aplicações mais conhecidas é a câmara de um pixel desenvolvida por investigadores da Universidade de Rice. Agora há outros instrumentos baseados na aquisição comprimida e também aplicações nas áreas da comunicação, medicina, astronomia e outros campos de investigação. Neste trabalho foi projetada e implementada a parte electrónica de uma câmara de aquisição comprimida de um só pixel. O subsistema desenvolvido é composto por um dispositivo digital de microespelhos (também conhecido por DMD - Digital Micromirror Device), para codificar o sinal, um subsistema de controlo, um subsistema de aquisição e um subsistema de armazenamento. Estes dois últimos subsistemas estão integrados numa placa de circuito impresso. As características mais importantes do sistema que desenvolvemos neste projecto são a possibilidade de atingir boa resolução com tempos de aquisição rápidos, o facto de que ele garante a sincronização entre a mudança de padrões de modulação do sinal e a aquisição do sinal, e que ele é relativamente acessível e facilmente reprodutível. O DMD é utilizado para executar padrões pseudo-aleatórios que permitem codificar uma imagem com menos amostragens do que o número de pixéis dessa imagem. Esta câmara utiliza um único elemento de detecção que permite reduzir tanto a complexidade como o custo deste sistema. Sistemas semelhantes podem ser usados para detectar com maior resolução em comprimentos de onda para os quais os instrumentos de medida só caros, volumosos ou até mesmo impossíveis de construir.Compressed sensing is a new concept that is attracting much research nowadays. The theory states that under certain conditions, only a relatively small number of samples need to be acquired for reconstructing an image or any signal in general. In other words, compressed sensing enables signal compression at the acquisition stage. In contrast, with traditional methods the data is compressed after acquisition. An outstanding characteristic of compressed sensing (CS) is that signals can be reconstructed at sampling rates lower than those required in the framework of the Shannon-Nyquist sampling theory. This theory has been increasingly developed, in areas like computational mathematics, signal processing, among others. Given that modern sensors are producing more and more information, applications of CS start to appear in areas where data compression is an essential requirement. The most known early application is the Rice University single pixel camera. Now, there are other instruments based on CS and applications to communications, medicine, astronomy and others research fields. In this work we designed and implemented the electronic acquisition and control subsystems of a compressive imaging single pixel camera. The subsystem developed is composed of a Digital Micromirror Device (DMD) for coding the signal, a controller subsystem, an acquisition subsystem and a storage subsystem. These last two subsystems are integrated in a printed circuit board. The most important features of the system that we designed in this work is tahta it can provide good resolution with fast acquisition times, that it ensures synchronization between the modification of the signal encoding patterns and the signal acquisition, and that it is relatively affordable and easy to reproducible. The DMD is used for creating pseudorandom patterns that allows to encode an image with fewer samples than the image’s number of pixels. This camera uses only a single detection element, enabling the reduction of the complexity and the cost of the system. Similar systems can be used for high resolution imaging in wavelengths for which currently instruments are expensive, bulky or even impossible to build

Cytotoxic activity and mechanism of action of organometallic complexes

Tese de mestrado, Bioquímica (Bioquímica Médica), Universidade de Lisboa, Faculdade de Ciências, 201

Towards a Global Zero for Nuclear Weapons: Three Lessons from Latin America

Full nuclear disarmament and the effective non-proliferation of atomic weapons are two of the most challenging aspirations of humankind. To tackle these issues, most analysts focus on the experiences of nuclear-weapon-owning states. A different perspective is taken here, however, by drawing lessons regarding global non-proliferation and disarmament from one of the most successful cases of compliance worldwide: namely, Latin America. Today, Latin America is one of the world's most compliant regions in nuclear non-proliferation and a key advocate of atomic disarmament. It was the first densely populated region in the world to become a nuclear-weapon-free zone; it hosts the only bilateral safeguard agency worldwide; and, it houses large reservoirs of uranium and other fissionable materials. Historically, nonetheless, Latin America showed variation in state behaviour vis-à-vis nuclear affairs, with some countries being proactive within the non-proliferation regime and others distancing themselves from it. It is, therefore, a relevant case to consider when looking for lessons on global non-proliferation and disarmament. Three lessons can be drawn from its experience: a broad understanding of confidence-building measures is vital to facilitate lasting trust among countries; institutional creativity is imperative in the nuclear non-proliferation and disarmament realms; and, good communication is crucial to compliance. Latin America's experiences with non-proliferation and disarmament efforts can be applied to Europe, the Middle East, South Asia, and East Asia. Effective nuclear disarmament and non-proliferation depends on creating background conditions for cooperation, trust, and institutions. These elements must lead to a cognitive change in how people understand the nature of nuclear weapons

Fresh Wind Out of the South: What to Expect from a Binding Nuclear Ban Treaty

On the 75th anniversary of the bombing of Hiroshima and Nagasaki, an overlooked event has shaken nuclear politics. With its 50th ratifier, the Treaty on the Prohibition of Nuclear Weapons (TPNW/Ban Treaty) is set to become binding. The pros and cons of that treaty, the possible consequences going forwards, and three possible future scenarios are worthy of analysis. Until now, nuclear bombs were the only weapons of mass destruction not forbidden by international law. Even though atomic powers hold legal obligations to disarm, progress in that area is slow - if happening at all. The Ban Treaty intends to fill this legal gap and speed up disarmament negotiations. The TPNW is a polemical treaty. Criticisms range from how broadly its text was framed, to the lack of substance on technical procedures, to who it was who negotiated it. Being a treaty boycotted by nuclear powers, critics point out that it will not have any practical effect whatsoever - and, if somehow so, only a negative one. Most criticisms overlook the normative foundations of the Ban Treaty, as well as its main target: creating, in the long run, an ideational and social environment that enables a non-nuclear-weapons peace. It should be regarded as one more instrument to pressure for nuclear disarmament and ensure non-proliferation. The entry into force of the Ban Treaty is, by itself, a relevant event, with consequences for existing disarmament talks. Atomic arsenals will not be immediately dismantled. In the long run, however, increased public and social pressure may lead to an effective stimagitisation of nuclear weapons, rendering a nuclear-free world possible. With an active civil society and being a member of the Atlantic Alliance, Germany is in the position to become a bridge between state parties to and boycotters of the TPNW

Detection of the SARS-CoV-2 UK variant in Portugal

Communication abstract: Proceedings of the 5th International Congress of CiiEM - Reducing inequalities in Health and Society, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from June 16th to 18th, 2021.This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.At the end of 2020, a new highly transmissible variant of SARS-CoV-2 was discovered in the United Kingdom (UK). This work aims to identify potential cases of the UK variant in Portugal using routine diagnostic samples. A total of 26 out of 43 positive samples that were identified by RT-PCR as suspects were confirmed through sequencing to be the SARS-CoV-2 UK variant. The first case of the UK variant identified by us was in samples collected on 21 December 2020 at Lisbon airport in travelers from Manchester and London.info:eu-repo/semantics/publishedVersio