4,126 research outputs found

    Multivariate analysis for the classification and differentiation of Madeira wines according to main grape varieties

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    In order to differentiate and characterize Madeira wines according to main grape varieties, the volatile composition (higher alcohols, fatty acids, ethyl esters and carbonyl compounds) was determined for 36 monovarietal Madeira wine samples elaborated from Boal, Malvazia, Sercial and Verdelho white grape varieties. The study was carried out by headspace solid-phase microextraction technique (HS-SPME), in dynamic mode, coupled with gas chromatography–mass spectrometry (GC–MS). Corrected peak area data for 42 analytes from the above mentioned chemical groups was used for statistical purposes. Principal component analysis (PCA) was applied in order to determine the main sources of variability present in the data sets and to establish the relation between samples (objects) and volatile compounds (variables). The data obtained by GC–MS shows that the most important contributions to the differentiation of Boal wines are benzyl alcohol and (E)-hex-3-en-1-ol. Ethyl octadecanoate, (Z)-hex-3-en-1-ol and benzoic acid are the major contributions in Malvazia wines and 2-methylpropan-1-ol is associated to Sercial wines. Verdelho wines are most correlated with 5-(ethoxymethyl)-furfural, nonanone and cis-9-ethyldecenoate. A 96.4% of prediction ability was obtained by the application of stepwise linear discriminant analysis (SLDA) using the 19 variables that maximise the variance of the initial data set

    Geological raw materials from a mesolithic archaeological site in NW Portugal

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    This is an author’s version (C. Alves) and not the final published text. The final published text can be found in: Proceedings 2019, 24(1), 10; https://doi.org/10.3390/IECG2019-06222The present work concerns the study of geological raw materials obtained from an excavation site located in Serra da Cabreira (NW Portugal). The majority of the artifacts are made in quartz varieties (with minor occurrences of flint). Milky quartz is dominant, being similar to diverse occurrences of quartz veins in the immediate neighborhood. There are diverse other quartz varieties, indicating the possibility of locations farther away from the shelter. The study of geological raw materials can be seen as an important source of archaeological information, illustrating the evolution of past relationships between humans and geological resources, and also providing relevant information for the present and future, considering namely the extremely low environmental impact of the processing of raw materialsThe first author (Pedro Xavier) would like to thank the Fundação para a Ciência e a Tecnologia (Foundation for Science and Technology) for the Ph.D. scholarship, reference (SFRH/BD/120806/2016). The Lab2PT—Landscapes, Heritage and Territory laboratory—AUR/04509 is supported by the Portuguese “Fundação para a Ciência e a Tecnologia” (Portuguese funds and where applicable the FEDER co-financing, in the aim of the new partnership agreement PT2020 and COMPETE2020—POCI 010145 FEDER 007528)

    A adoção do padrão internacional de relatórios financeiros em portugal: podem os custos esperados ser reduzidos?

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    In this paper we use a cost-benefit framework to discuss some of the expected effects related to the Portuguese adoption of the International Financial Reporting Standards (IFRS). Given the circumstances underlying this implementation, we anticipate that the overall net result following an analysis of costs and benefits will be negative. Therefore, we also examine what seems to be the causal factor behind this outcome and a potential way of reducing the net cost of adopting the IFRS. The costs are related to the professional updating of accounting skills of those directly or indirectly involved in the accounting process. A part of these costs will be incremental and permanent over time mainly due to the fact that two accounting systems will be kept in place. The adoption of a single accounting system, that based on the IFRS, would appear to be a possible solution to reduce such costs

    eLabs – platform for online laboratory management

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    We observe, today, an unprecedented development of information technologies in various organizational, social and economic fields. The Web is the main driver of this evolution from a simple display system of linked pages to a powerful platform for information and communication, having the interaction, the dynamism and multimedia resources their main features. At the organizational level, the Web has introduced several improvements, turning the business processes more effective and centered on users. The deployment of portals to support management and communication in organizations was the first step in the integration of information technologies in several fields of organizations. One of the most relevant technologies to support business process management is workflow, representing the most significant solution for process automation and information management inside an organization. According to Hales (1997) workflow is a proactive management system that manages the workflow among the participants (users or other systems), according to predefined procedures that define the tasks. This article discusses the development of a platform for online laboratory management based on workflow technologies, with the main goals to improve communication, cooperation and integrated management of resources, promoting greater efficiency in laboratory management. The eLabs platform is been used in Instituto Politécnico de Bragança for laboratory management, integrating the management of internal and external services, equipment, resources and tasks. The results obtained demonstrate an improvement in the efficiency of resources management and the enhancement of quality of services realized inside the institution and to the community

    Debugging mixed-signal circuits via the IEEE1149.4 Std. - analysis of limitations and requirements

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    Debugging mixed-signal circuits is traditionally seen as a complex task due to the presence of an analog part and the necessary interaction with a digital part. The use of debug tools that require physical access suffers from the same restrictions that led to the use of debug tools based on electronic access to digital circuits. While the IEEE1149.4 test infrastructure enables the structural and parametric test of mixed-signal boards, through electronic access, its use for debug purposes is still far from reaching a wide acceptance, namely due to the lack of a debug methodology. This work analyses several access mechanisms for Controllability, Observability and Verification operations via the IEEE1149.4 infrastructure, with an emphasis on the analysis of its limitations and requirements

    Formal verification of a space system's user Interface with the IVY workbench

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    This paper describes the application of the IVY workbench to the formal analysis of a user interface for a safety-critical aerospace system. The operation manual of the system was used as a requirement document, and this made it possible to build a reference model of the user interface, focusing on navigation between displays, the information provided by each display, and how they are interrelated. Usability-related property specification patterns were then used to derive relevant properties for verification. This paper discusses both the modeling strategy and the analytical results found using the IVY workbench. The purpose of the reference model is to provide a standard against which future versions of the interface may be assessed.EPSRC - Engineering and Physical Sciences Research Council(EP/G059063/1)This work was partly funded by project ref. NORTE-07-0124-FEDER-000062, co-financed by the North Portugal Regional Operational Programme (ON.2 O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF), and by national funds, through the Portuguese foundation for science and technology (FCT)

    Highly diastereoselective synthesis of 2-azabicyclo[2.2.1]hept-5-ene derivatives : bronsted acid catalized aza-diels-alder reaction between cyclopentadiene and imino-acetates with two chiral auxiliaries

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    The cycloaddition between protonated glyoxylate imines possessing two chiral auxiliaries, N-(S)- or N-(R)-1-phenylethyl and (-)-8-phenylmenthyl or (+)-8- phenylneomenthyl, and cyclopentadiene is described. The absolute configuration of all adducts formed was unequivocally assigned through NMR, specific optical rotation and X-ray data of appropriated derivatives. Experimental results confirm the highly exoselectivity for these aza-Diels–Alder reactions, single adducts being obtained from combinations of (8PM)-(R-PEA) and (8PNM)-(S-PEA).Thanks are due to Fundacao para a Ciencia e Tecnologia (FCT) for financial support given to Faculdade de Ciencias do Porto (project PTDC/QUI/67407/2006) and for financial support through the re-equipment program REDE/1517/RMN/2005

    Past, present and future distributions of an Iberian endemic, Lepus granatensis: ecological and evolutionary clues from species distribution models

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    The application of species distribution models (SDMs) in ecology and conservation biology is increasing and assuming an important role, mainly because they can be used to hindcast past and predict current and future species distributions. However, the accuracy of SDMs depends on the quality of the data and on appropriate theoretical frameworks. In this study, comprehensive data on the current distribution of the Iberian hare (Lepus granatensis) were used to i) determine the species' ecogeographical constraints, ii) hindcast a climatic model for the last glacial maximum (LGM), relating it to inferences derived from molecular studies, and iii) calibrate a model to assess the species future distribution trends (up to 2080). Our results showed that the climatic factor (in its pure effect and when it is combined with the land-cover factor) is the most important descriptor of the current distribution of the Iberian hare. In addition, the model's output was a reliable index of the local probability of species occurrence, which is a valuable tool to guide species management decisions and conservation planning. Climatic potential obtained for the LGM was combined with molecular data and the results suggest that several glacial refugia may have existed for the species within the major Iberian refugium. Finally, a high probability of occurrence of the Iberian hare in the current species range and a northward expansion were predicted for future. Given its current environmental envelope and evolutionary history, we discuss the macroecology of the Iberian hare and its sensitivity to climate change.P.A. was supported by the Vicerrectorado de Investigación of the University of Malaga and partially by the project CGL2009-11316/BOS of the Spanish Government and FEDER. Currently, P.A. holds a Beatriu de Pinós fellowship funded by “Comissionat per a Universitats i Recerca del Departament d’Innovació, Universitats i Empresa” of the Generalitat de Catalunya, and the COFUND Programme - Marie Curie Actions under 7th Marc Programme of the European Community. J.M.-F. was funded from the SFRH/BPD/43264/2008 post-doctoral grant by by Portuguese Fundação para a Ciência e a Tecnologia (FCT) and the European Social Fund. Financial support was partially obtained from the Research Projects PTDC/BIA-EVF/111931/2009 and PTDC/BIA-EVF/115069/2009, by FCT and FEDER.Peer Reviewe
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