82 resultados para quantum technologies

em Université de Lausanne, Switzerland


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There is no doubt about the necessity of protecting digital communication: Citizens are entrusting their most confidential and sensitive data to digital processing and communication, and so do governments, corporations, and armed forces. Digital communication networks are also an integral component of many critical infrastructures we are seriously depending on in our daily lives. Transportation services, financial services, energy grids, food production and distribution networks are only a few examples of such infrastructures. Protecting digital communication means protecting confidentiality and integrity by encrypting and authenticating its contents. But most digital communication is not secure today. Nevertheless, some of the most ardent problems could be solved with a more stringent use of current cryptographic technologies. Quite surprisingly, a new cryptographic primitive emerges from the ap-plication of quantum mechanics to information and communication theory: Quantum Key Distribution. QKD is difficult to understand, it is complex, technically challenging, and costly-yet it enables two parties to share a secret key for use in any subsequent cryptographic task, with an unprecedented long-term security. It is disputed, whether technically and economically fea-sible applications can be found. Our vision is, that despite technical difficulty and inherent limitations, Quantum Key Distribution has a great potential and fits well with other cryptographic primitives, enabling the development of highly secure new applications and services. In this thesis we take a structured approach to analyze the practical applicability of QKD and display several use cases of different complexity, for which it can be a technology of choice, either because of its unique forward security features, or because of its practicability.

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Prognosis of early breast cancer patients is significantly improved with the use of adjuvant therapies. Various guidelines have been proposed to select patients who will derive the most benefit from such treatments. However, classifications have limited usefulness in subsets of patients such as those with node negative breast cancer. The 2007 St. Paul de Vence Clinical Practice Recommendations proposed to consider adjuvant therapy in accordance with the 10-year relapse-free survival reduction estimated by Adjuvant! Online. However, many limitations remain regarding the use of Adjuvant! Online. Among them, adverse prognostic and/or predictive factors such as vascular invasion, mitotic activity, progesterone receptor negativity, and HER-2 expression are not incorporated in the routine clinical decision process. Our group has therefore issued guidelines based on the consideration of both Adjuvant! Online calculations and the prognostic and/or predictive effects of these markers. In addition, web-accessible comprehensive tables summarizing these recommendations are provided.

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Cet article présente les résultats de la revue systématique: Inglis SC, Clark RA, McAlister FA, et al. Structured telephone support or telemonitoring programmes for patients with chronic heart failure. Cochrane Database Systematic Reviews 2010, Issue 8. Art. No.:CD007228. DOI:10.1002/14651858.CD007228.pub2. PMID: 20687083

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Quantum indeterminism is frequently invoked as a solution to the problem of how a disembodied soul might interact with the brain (as Descartes proposed), and is sometimes invoked in theories of libertarian free will even when they do not involve dualistic assumptions. Taking as example the Eccles-Beck model of interaction between self (or soul) and brain at the level of synaptic exocytosis, I here evaluate the plausibility of these approaches. I conclude that Heisenbergian uncertainty is too small to affect synaptic function, and that amplification by chaos or by other means does not provide a solution to this problem. Furthermore, even if Heisenbergian effects did modify brain functioning, the changes would be swamped by those due to thermal noise. Cells and neural circuits have powerful noise-resistance mechanisms, that are adequate protection against thermal noise and must therefore be more than sufficient to buffer against Heisenbergian effects. Other forms of quantum indeterminism must be considered, because these can be much greater than Heisenbergian uncertainty, but these have not so far been shown to play a role in the brain.

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Résumé : Désormais, la lutte contre le blanchiment d'argent constitue une priorité pour les Etats et les gouvernements dans le but, d'une part, de préserver l'économie et l'intégrité des places financières et, d'autre part, de priver les organisations criminelles des ressources financières. Dans ce contexte, la préoccupation majeure des autorités algériennes en charge de la lutte contre ce phénomène est de mettre en place un dispositif capable de détecter les mécanismes de blanchiment, d'en évaluer la menace et sur la base de cette connaissance, de définir et de déployer les moyens de riposte les plus efficaces et efficients. Mais nous constatons que mener des enquêtes de blanchiment en conséquence à un crime sous-jacent a montré ses limites en matière d'établissement de preuves, d'élucidation d'affaires et de recouvrement des avoirs. Par ailleurs, nous pensons qu'il serait plus judicieux de mettre en place en amont un contrôle «systématique» des flux financiers et des opérations inhabituelles et/ou suspectes et de là, identifier d'éventuelles opérations de blanchiment, sans forcément connaître le crime initial, en veillant au maintien de l'équilibre entre le «tout sécuritaire» orienté vers la surveillance accrue des flux et la préservation de la vie privée et des libertés individuelles. Notre thèse apporte un regard critique sur le dispositif actuel de lutte contre le blanchiment existant en Algérie que nous évaluons et sur lequel nous relevons plusieurs lacunes. Pour répondre aux problèmes identifiés nous proposons des solutions stratégiques, organisationnelles, méthodologiques et technologiques intégrées dans un cadre opérationnel cohérent au niveau national et international.

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Since 1990, several techniques have been developed to photochemically inactivate pathogens in platelet concentrates, potentially leading to safer transfusion therapy. The three most common methods are amotosalen/UVA (INTERCEPT Blood System), riboflavin/UVA-UVB (MIRASOL PRT), and UVC (Theraflex-UV). We review the biology of pathogen inactivation methods, present their efficacy in reducing pathogens, discuss their impact on the functional aspects of treated platelets, and review clinical studies showing the clinical efficiency of the pathogen inactivation methods and their possible toxicity.

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The assessment of medical technologies has to answer several questions ranging from safety and effectiveness to complex economical, social, and health policy issues. The type of data needed to carry out such evaluation depends on the specific questions to be answered, as well as on the stage of development of a technology. Basically two types of data may be distinguished: (a) general demographic, administrative, or financial data which has been collected not specifically for technology assessment; (b) the data collected with respect either to a specific technology or to a disease or medical problem. On the basis of a pilot inquiry in Europe and bibliographic research, the following categories of type (b) data bases have been identified: registries, clinical data bases, banks of factual and bibliographic knowledge, and expert systems. Examples of each category are discussed briefly. The following aims for further research and practical goals are proposed: criteria for the minimal data set required, improvement to the registries and clinical data banks, and development of an international clearinghouse to enhance information diffusion on both existing data bases and available reports on medical technology assessments.

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The dissertation investigates some relevant metaphysical issues arising in the context of spacetime theories. In particular, the inquiry focuses on general relativity and canonical quantum gravity. A formal definition of spacetime theory is proposed and, against this framework, an analysis of the notions of general covariance, symmetry and background independence is performed. It is argued that many conceptual issues in general relativity and canonical quantum gravity derive from putting excessive emphasis on general covariance as an ontological prin-ciple. An original metaphysical position grounded in scientific essential- ism and causal realism (weak essentialism) is developed and defended. It is argued that, in the context of general relativity, weak essentialism supports spacetime substantivalism. It is also shown that weak essentialism escapes arguments from metaphysical underdetermination by positing a particular kind of causation, dubbed geometric. The proposed interpretive framework is then applied to Bohmian mechanics, pointing out that weak essentialism nicely fits into this theory. In the end, a possible Bohmian implementation of loop quantum gravity is considered, and such a Bohmian approach is interpreted in a geometric causal fashion. Under this interpretation, Bohmian loop quantum gravity straightforwardly commits us to an ontology of elementary extensions of space whose evolution is described by a non-local law. The causal mechanism underlying this evolution clarifies many conceptual issues related to the emergence of classical spacetime from the quantum regime. Although there is as yet no fully worked out physical theory of quantum gravity, it is argued that the proposed approach sets up a standard that proposals for a serious ontology in this field should meet.

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La contrefaçon de billets de banque a considérablement évolué avec l'apparition des technologies numériques de reproduction. Gouverné autrefois par des professionnels bien organisés, le phénomène de la contrefaçon n'est plus aujourd'hui l'apanage de quelques initiés mais est répandu dans une large communauté de faussaires. Les systèmes et les acteurs de la lutte contre la contrefaçon doivent s'adapter à ce nouveau modèle afin de pallier les impacts économiques, personnels et psychologiques de la contrefaçon sur la société. Au coeur des débats sociologiques et éthiques, les autorités politiques, les banques nationales, la police et les experts tentent d'endiguer le problème de façon parfois quelque peu inadéquate et obsolète. L'analyse de données statistiques permet de dégager les tendances actuelles et d'identifier les changements majeurs entre deux époques.