25 research outputs found

    The general purpose analog computer and computable analysis are two equivalent paradigms of analog computation

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    In this paper we revisit one of the rst models of analog computation, Shannon's General Purpose Analog Computer (GPAC). The GPAC has often been argued to be weaker than computable analysis. As main contribution, we show that if we change the notion of GPACcomputability in a natural way, we compute exactly all real computable functions (in the sense of computable analysis). Moreover, since GPACs are equivalent to systems of polynomial di erential equations then we show that all real computable functions can be de ned by such models

    Solving analytic differential equations in polynomial time over unbounded domains

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    In this paper we consider the computational complexity of solving initial-value problems de ned with analytic ordinary diferential equations (ODEs) over unbounded domains of Rn and Cn, under the Computable Analysis setting. We show that the solution can be computed in polynomial time over its maximal interval of de nition, provided it satis es a very generous bound on its growth, and that the function admits an analytic extension to the complex plane

    Immobilized lignin peroxidase-like metalloporphyrins as reusable catalysts in oxidative bleaching of industrial dyes

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    Synthetic and bioinspired metalloporphyrins are a class of redox-Active catalysts able to emulate several enzymes such as cytochromes P450, ligninolytic peroxidases, and peroxygenases. Their ability to perform oxidation and degradation of recalcitrant compounds, including aliphatic hydrocarbons, phenolic and non-phenolic aromatic compounds, sulfides, and nitroso-compounds, has been deeply investigated. Such a broad substrate specificity has suggested their use also in the bleaching of textile plant wastewaters. In fact, industrial dyes belong to very different chemical classes, being their effective and inexpensive oxidation an important challenge from both economic and environmental perspective. Accordingly, we review here the most widespread synthetic metalloporphyrins, and the most promising formulations for large-scale applications. In particular, we focus on the most convenient approaches for immobilization to conceive economical affordable processes. Then, the molecular routes of catalysis and the reported substrate specificity on the treatment of the most diffused textile dyes are encompassed, including the use of redox mediators and the comparison with the most common biological and enzymatic alternative, in order to depict an updated picture of a very promising field for large-scale applications

    Computing domains of attraction for planar dynamics

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    In this note we investigate the problem of computing the domain of attraction of a ow on R2 for a given attractor. We consider an operator that takes two inputs, the description of the ow and a cover of the attractors, and outputs the domain of attraction for the given attractor. We show that: (i) if we consider only (structurally) stable systems, the operator is (strictly semi-)computable; (ii) if we allow all systems de ned by C1-functions, the operator is not (semi-)computable. We also address the problem of computing limit cycles on these systems

    Covalent and noncovalent hybrids of di-amino porphyrin functionalized graphene oxide and their interaction with gold nanoparticles

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    Porphyrin functionalization of graphene oxide (GO) influenced the plasmonic effect of gold nanoparticles (AuNP). The former was achieved by modification of GO with 5,10-bis(4-aminophenyl)-15,20-diphenylpor-phyrin, P(NH2)2,adj, by noncovalent interactions as well as by covalent association, following standard chemis-try. The success of the chemical functionalization of GO with P(NH2)2,adj, was confirmed by FTIR. Steady-state and time-resolved fluorescence showed a strong fluorescence quenching of porphyrin in the presence of GO, indicative of a photoinduced electron transfer process from porphyrin units to GO, which acts as an electron acceptor. The surface plasmon coupling effect promoted by the AuNP@GO hybrids, proved to be effective only in the case of the noncovalent hybrid, detected through the decrease of the porphyrin fluorescence lifetime and increase in the emission intensity in solution, in good agreement with FLIM results on deposited samples.info:eu-repo/semantics/publishedVersio

    Co-production pathway of an end-to-end climate service for improved decision-making in the wine sector

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    Climate services are one of the tools that can support the agriculture sector to address the impacts of climate change on agricultural production systems, not only considering climatic aspects but also social needs. This work describes the knowledge co-production journey of the EU-funded project MED-GOLD to create an end-to-end climate service for wine sector users. In this work, co-production is understood as an iterative, interactive and collaborative process among an interdisciplinary group of scientists and users that were engaged, involved, and empowered. The co-production process included activities to raise awareness on the vulnerability of grape and wine production to climate change, exchange knowledge between climate service providers and users, and co-develop customised climate services, such as the MED-GOLD Dashboard. Lessons learned are that repeated interaction between scientists and users allow to better frame research questions, jointly decide how to address these questions, and test the outcomes with feedback from real-world decision-makers. Furthermore, having a user who co-developed the service and helped assess its added value was key to ensure that it could truly inform decision-making needs and to promote its broader uptake by the wine sector community. Although the MED-GOLD Dashboard constitutes the most tangible result of this collaboration, the outcomes of co-production also encompass the joint learning process, the shared sense of ownership, and the co-creation of new knowledge between scientists and stakeholders. Nevertheless, further research will be needed to understand how the knowledge coproduced with a single user can be scaled up to users with other profiles and requirements

    Monitoring climate related risk and opportunities for the wine sector: The MED-GOLD pilot service

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    MED-GOLD was a 54-months research and innovation project, whose main aim was to co-develop climate services for three staples of the Mediterranean food system, namely grapes, olives and durum wheat. This paper describes the methodology adopted for the co-development of the pilot climate service for the wine sector, focusing on the Douro Wine Region in northern Portugal. In the first step, the MED-GOLD industrial partner SOGRAPE identified key decisions and users’ needs for the wine sector in the Douro region by involving managers from their own vineyards in that region. From this information, the relevant bioclimatic indicators (and associated essential climate variables) were selected. Afterwards, two compound risk indices, the Sanitary and Heat Risk indices, were introduced as a combination of some of the aforementioned bioclimatic indicators. This methodological work was validated against the empirical climate characterization for the region of interest, of several ‘bad’ and ‘good’ years chosen by users according to their recollections of grape and wine production outcomes, namely quality and yields. In this paper, the overall strategy for selection of these years is presented. The components of the service based on historical climate, seasonal predictions and longer-term climate projections are described along with the visual interface developed: the MED-GOLD Dashboard, an interactive tool that displays detailed historical climate data, seasonal predictions and climate projections. The Dashboard consists of an ICT platform with a map-based user-focused front end to aid easy access to and manipulation of the data. The Dashboard was iteratively co-designed with the users to ensure their needs were met

    Soccer and homosexuality: the conflicts that lie within the affective game of the coach-adolescent athlete relationship

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    Discussions regarding homosexuality within a sports context are mediated by emotional nuances, especially in the world of soccer, where practitioners are required to have attributes such as strength, masculinity and aggressiveness. As a consequence, this work aimed to analyze the symbolic representation of homosexual relationships between adolescent soccer players and their coaches; and, furthermore, to understand the intention behind homoerotic relationships that are established between members of the management team and its players. In this study, researchers used the life history methodology, with participation from three adolescent athletes, ages 14, 15 and 16, and three former athletes, ages 26, 28 and 45, who we called speakers. Based on the collection and analysis of research participants’ testimonies, homosexual relations were found to have occurred between athletes and coaches, or between athletes and other members of the management team, as a part of a “social contract” that is exclusively linked to their professional objectives. These relationships appear to be purely objective; authentic affective links are absent, due apparently to the transient nature of the athletes in these groups. Too, this context is usually marked by the athlete’s physical and emotional vulnerability, and the agreements he makes within this context are accompanied with moral dilemmas, because such adolescents idealize the coach as a paternal archetype.“Futebol e homossexualidade: Os conflitos que se encontram dentro do jogo afetivo da relação treinador-atleta adolescente.” As discussões a respeito da homossexualidade no contexto esportivo são mediadas por nuanças emocionais, especialmente no mundo do futebol que exige de seus praticantes atributos de força, virilidade e agressividade. Por este motivo este trabalho teve como objetivos diagnosticar existência de relações homossexuais entre atletas adolescentes da modalidade de futebol e seus técnicos e sua representação simbólica e ainda, compreender a intencionalidade das relações homoafetivas que se estabelecem entre componentes da equipe diretiva e os jogadores. Esta pesquisa é de natureza qualitativa e a técnica adotada foi a “história de vida” e a participação de três atletas adolescentes em atividade, com idade de 14, 15 e 16 anos e três ex-atletas profissionais, com idades 26, 28 e 45 anos serviram de base metodológica. A partir da análise e tratamento dos depoimentos verificou-se que ocorreram relações homossexuais nas categorias de base envolvendo técnico e atleta, ou com outros membros da equipe diretiva, como parte dos contratos sociais, ligados exclusivamente a objetivos profissionais. Estas relações parecem ser puramente objetais, não parecendo existir vínculos afetivos duradouros, aparentemente, devido à natureza transitória de atletas nesses grupos. Também, nesses ambientes, muitas vezes marcados pela vulnerabilidade física e emocional dos atletas, os acertos para as relações homossexuais são permeadas por dilemas morais, tendo em vista que os atletas adolescentes idealizam o treinador como o arquétipo paterno ideal.“El fútbol y la homosexualidad: Los conflictos que se encuentran dentro del juego afectivo de la relación atleta-entrenador de los adolescentes.” Las discusiones sobre la homosexualidad en contexto deportivo están mediadas por matices emocionales, sobre todo en el mundo del fútbol que exige a sus jugadores atributos como la fuerza, la virilidad y los jugadores. En este estudio, los investigadores utilizaron la metodología de la historia de vida, con la participación de tres atletas adolescentes, con 14, 15 y 16 años, y tres ex atletas con 26, 28 y 45 años, que llamamos ‘oradores’. Basado en la recogida y análisis de testimonios de participantes en la investigación, se encontró que las relaciones homosexuales que se han producido entre los atletas y entrenadores, o entre atletas y otros miembros del equipo de gestión, son como parte de un “contrato social” que está vinculado exclusivamente a sus objetivos profesionales. Estas relaciones parecen ser solamente como un objeto; porque a veces no hay vínculos afectivos auténticos, debido aparentemente a la naturaleza transitoria de los atletas en estos grupos. Demasiado, este contexto es generalmente marcado por la vulnerabilidad física y emocional del deportista, y los acuerdos que hace dentro de este contexto se acompañan con dilemas morales, debido a que tales adolescentes idealizan el entrenador como un arquetipo paterno. la agresividad. Por lo tanto, este estudio tuvo como objetivo diagnosticar la existencia de relaciones homosexuales entre adolescentes atletas de fútbol y sus entrenadores y la representación simbólica de estas relaciones. También comprender la intencionalidad de las relaciones homoafetivas que se intercambian entre algunos componentes del equipo directivo y(undefined
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