100 research outputs found

    On Graph Refutation for Relational Inclusions

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    We introduce a graphical refutation calculus for relational inclusions: it reduces establishing a relational inclusion to establishing that a graph constructed from it has empty extension. This sound and complete calculus is conceptually simpler and easier to use than the usual ones.Comment: In Proceedings LSFA 2011, arXiv:1203.542

    On Graphical Calculi for Modal Logics

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    We present a graphical approach to classical and intuitionistic modal logics, which provides uniform formalisms for expressing, analysing and comparing their semantics. This approach uses the flexibility of graphical calculi to express directly and intuitively the semantics for modal logics. We illustrate the benefits of these ideas by applying them to some familiar cases of classical and intuitionistic multi-modal logics.Cálculos Gráficos para lógicas modais Apresentamos uma abordagem gráfica para as lógicas modais clássica e intuicionista, capaz de fornecer formalismos uniformes para expressar, analisar e comparar suas respectivas semânticas. Tal abordagem utiliza a flexibilidade dos cálculos gráficos para expressar, direta e intuitivamente, a semântica das lógicas modais. Ilustramos os benefícios dessas ideias aplicando-as a alguns casos conhecidos de lógicas multimodais clássica e intuicionista.---Artigo em inglês

    On Graphical Calculi for Modal Logics

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    We present a graphical approach to classical and intuitionistic modal logics, which provides uniform formalisms for expressing, analysing and comparing their semantics. This approach uses the flexibility of graphical calculi to express directly and intuitively the semantics for modal logics. We illustrate the benefits of these ideas by applying them to some familiar cases of classical and intuitionistic multi-modal logics

    Validades Existenciais e Enigmas Relacionados

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    A lógica não contém teoremas puramente existenciais: as únicas sentenças existenciaisválidas são aquelas com análogas universais válidas. Aqui, mostramos que istorealmente é assim quando corretamente interpretado: toda validade ex- istencial possuiuma análoga universal simples, que também é válida. Também caracterizamos validadesuniversais e existenciais em termos de tautologias.Logic does not have purely existential theorems: the only existentialsentences that are valid are those with valid universal analogues. Here, we showindeed this is so, when properly interpreted: every existential validity has asimple universal analogue, which is also valid. We also characterize existentialand universal validities in terms of tautologies

    The use of a geographic information system to increase outdoor tourism

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    Purpose: Outdoor tourism is a growing segment that still requires data for planning and management. Aimed to present the potential of the Geographic Information System (GIS) to improve outdoor tourism in the North of Portugal. To achieve this purpose, a case study was conducted on developing a Web-GIS in Northern Portugal. Methodology: Four steps were followed to develop the GIS tool with information about outdoor tourism in the North of Portugal. In the first step, municipalities in the North of Portugal sent information about outdoor activities. In the second step, the data were georeferenced and associated. In the last step, a Web-GIS was developed. Findings: The development of tools is an important source of support for tourism. This study identified that a tool such as the GIS could support a destination's decision-making and promotional processes, besides providing detailed information to the tourist and facilitating travel planning. Practical implications: GIS provides effective planning of outdoor tourism, once this tool allows an effective search of the tourist offer and, from the tourist's perspective, relevant suggestions of visits according to their location are presented, facilitating their experience in the region. Originality: Several studies relate to GIS and tourism, but there is still a gap in specific studies on outdoor activities. So, this study presents the importance of GIS to improve outdoor tourism in the North region of Portugal. Understanding this importance is essential in planning and managing tourism, helping further policymaking and marketing strategies.B913-0565-0908 | Elvira VieiraN/

    Bio-based solar energy harvesting for onsite mobile optical temperature sensing in Smart Cities

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    The Internet of Things (IoT) fosters the development of smart city systems for sustainable living and increases comfort for people. One of the current challenges for sustainable buildings is the optimization of energy management. Temperature monitoring in buildings is of prime importance, as heating account for a great part of the total energy consumption. Here, a solar optical temperature sensor is presented with a thermal sensitivity of up to 1.23% °C-1 based on sustainable aqueous solutions of enhanced green fluorescent protein and C-phycocyanin from biological feedstocks. These photonic sensors are presented under the configuration of luminescent solar concentrators widely proposed as a solution to integrate energy-generating devices in buildings, as windows or façades. The developed mobile sensor is inserted in IoT context through the development of a self-powered system able to measure, record, and send data to a user-friendly website.publishe

    Impact of citrate and lipid-functionalized magnetic nanoparticles in dehydropeptide supramolecular magnetogels: properties, design and drug release

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    Currently, the nanoparticle functionalization effect on supramolecular peptide-based hydrogels remains undescribed, but is expected to affect the hydrogels' self-assembly and final magnetic gel properties. Herein, two different functionalized nanoparticles: citrate-stabilized (14.4 ± 2.6 nm) and lipid-coated (8.9 ± 2.1 nm) magnetic nanoparticles, were used for the formation of dehydropeptide-based supramolecular magnetogels consisting of the ultra-short hydrogelator Cbz-L-Met-Z-ΔPhe-OH, with an assessment of their effect over gel properties. The lipid-coated nanoparticles were distributed along the hydrogel fibers, while citrate-stabilized nanoparticles were aggregated upon gelation, which resulted into a heating efficiency improvement and decrease, respectively. Further, the lipid-coated nanoparticles did not affect drug encapsulation and displayed improved drug release reproducibility compared to citrate-stabilized nanoparticles, despite the latter attaining a stronger AMF-trigger. This report points out that adsorption of nanoparticles to hydrogel fibers, which display domains that improve or do not affect drug encapsulation, can be explored as a means to optimize the development of supramolecular magnetogels to advance theranostic applications.Ministerio de Economía y Competitividad (MINECO, Spain) under the Grant (CTM2017-84050-R), Xunta de Galicia/FEDER (IN607A 2018/5 and Centro Singular de Investigación de Galicia accreditation 2019-2022, ED431G 2019/06), 0712_ACUINANO_1_E, 0624_2IQBIONEURO_6_E and NANOCULTURE cofounded by FEDER through the program Interreg V-A España-Portugal (POCTEP), NANOCULTURE (ERDF: 1.102.531) Interreg Atlantic Area, the European Union (European Regional Development Fund-ERDF)

    Oxidative precipitation synthesis of calcium-doped manganese ferrite nanoparticles for magnetic hyperthermia

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    Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this work, nanoparticles of calcium-doped manganese ferrites (CaxMn1−xFe2O4) functionalized with citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis, in which the temperature and Ca/Mn ratio were found to influence the particles microstructure and morphology. Consequently, changes were obtained in the optical and magnetic properties that were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy studies were carried out to assess the microstructural changes associated with stoichiometry of the particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed high values of magnetization and heating efficiency for several alternating magnetic field conditions, compatible with biological applications. Hereby, the employed method provides a promising strategy for the development of particles with adequate properties for magnetic hyperthermia applications, such as drug delivery and cancer therapy.This work was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020, UIDP/04650/2020), CQUM (UIDB/00686/2020), CICECO Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020) and by Ministerio de Economía y Competitividad de España (PID2020-113704RB-I00 and PID2020-119242RB-I00), Xunta de Galicia (Centro Singular de Investigación de Galicia—Accreditation 2019-2022 ED431G 2019/06 and IN607A 2018/5 and project ED431C 2020-06), and European Union (EU-ERDF Interreg V-A—Spain-Portugal 0245_IBEROS_1_E, 0712_ACUINANO_1_E, and 0624_2IQBIONEURO_6_E, and Interreg Atlantic Area NANOCULTURE 1.102.531), and the European Union H2020-MSCA-RISE-2019 PEPSA-MATE project. S.R.S. (872233) Veloso acknowledges FCT for a PhD grant (SFRH/BD/144017/2019). Support from MAP-Fis Doctoral Programme is also acknowledged
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