Exploiting low-rank approximations of kernel matrics in denoising applicationS

The eigendecomposition of a kernel matrix can present a computational burden in many kernel methods. Nevertheless only the largest eigenvalues and corresponding eigenvectors need to be computed. In this work we discuss the Nystrom low-rank approximations of the kernel matrix and its applications in KPCA denoising tasks. Furthermore, the low-rank approximations have the advantage of being related with a smaller subset of the training data which constitute then a basis of a subspace. In a common algebraic framework we discuss the different approaches to compute the basis. Numerical simulations concerning the denoising are presented to compare the discussed approaches.info:eu-repo/semantics/publishedVersio

Identifying evoked potential response patterns using independent component analysis and unsupervised learning

Independent Component Analysis(ICA) is a pre-processing step widely used in brain studies. One of the most common problems in artifact elimination or brain activity related studies is the ordering and identification of the independent components(ICs). In this work, a novel procedure is proposed which combines ICA decomposition at trial level with an unsupervised learning algorithm (K-means) at participant level in order to enhance the related signal patterns which might represent interesting brain waves. The feasibility of this methodology is evaluated with EEG data acquired with participants performing on the Halstead Category Test. The analysis shows that it is possible to find the Feedback Error Negativity (FRN) Potential at single-trial level and relate its characteristics with the performance of the participant based on their knowledge of the abstract principle underlying the task.info:eu-repo/semantics/publishedVersio

Reflections on the Accounting Framework of Public Interest Cooperatives in Portugal

The purpose of this chapter is to determine whether the current accounting standards of public interest cooperatives in Portugal are adequate, taking into account the social object, particularly the pursuit of furthering public interest and the nature of the subjects that integrate it. Thus, through the methodology of content analysis, the authors analyze the various policies and accounting legislation as well as the literature available on this topic. Through the classification and analysis of the main characteristics of these cooperatives, the authors conclude that they should be subject to the Public Administration's accounting regime in order to respond to the needs of different users of information.info:eu-repo/semantics/publishedVersio

Impact of MOF-5 on pyrrolidinium-based poly(ionic liquid)/ionic liquid membranes for biogas upgrading

PostprintBearing in mind that Metal Organic Frameworks (MOFs) have remarkable CO2 adsorption selectivity and Mixed Matrix Membranes (MMMs) have been identified as potential solution for advancing the current state of the art of membrane separation technology, this work investigates the effect of combining a MOF, with high adsorption properties towards CO2 when compared to CH4 (MOF-5), with a blend of poly(ionic liquid)/ionic liquid (PIL/IL) for biogas upgrading. The blend system consisted of a pyrrolidinium-based PIL, poly([Pyr11][Tf2N]), and a free imidazolium-based IL, [C2mim][BETI]. The MOF-5 was incorporated at different loadings (10, 20, 30 wt%), and MMMs were prepared by solvent evaporation technique and characterized by diverse techniques (FTIR, SEM, TGA, puncture tests, water contact angle and single gas transport). The results showed that the free IL is miscible with the PIL, while MOF-5 particles were uniformly dispersed into the PIL/IL matrix. The formed PIL/IL/MOF-5 membranes revealed suitable thermal stability (Tonset up to 656 K) for biogas upgrading processes, but a loss of mechanical stability was found after the incorporation of MOF-5, and thus more rigid and fragile membranes were obtained. Besides, increasing MOF-5 content in the MMMs resulted in improved CO2 permeability. At 30 wt% of MOF-5 loading the CO2 permeability increased 133% when compared to that of the pristine PIL/IL membrane, while the ideal selectivity CO2/CH4 decreases. It was possible to demonstrate the relevance of studying different components within the polymeric matrix in order to assess not only thermal, mechanical and chemical properties, but also gas transport response.This work was supported by FCT (Fundação para Ciência e a Tecnologia) through the project PTDC/CTM-POL/2676/2014 and the Associate Laboratory for Green Chemistry - LAQV (UID/QUI/50006/2019). Ana R. Nabais and Luísa A. Neves are grateful to FCT/MCTES for their PhD grant (SFRH/BD/136963/2018) and FCT Investigador Contract (IF/00505/2014), respectively. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 745734

Space of memory and representation : Bouça da Cova da Moura (Ardegães, Maia, Northwest of Portugal)

Bouça da Cova da Moura is the local place-name attributed to a stretch of a plateau overlooking the Leça valley. Here, Neolithic burial mounds share their landscape setting with scatters of archaeological materials that include Bell Beaker fragments, idols and metalwork. Since these are mostly surface findings, their contexts have not yet been accurately determined. Another significant feature is the presence of prehistoric rock carvings. The plateau may thus be considered a public space, conceptually and physically built over time. Its significance and meanings were certainly created and transmitted through practices of memory construction which are representative of cultural identity and social cohesion.Le site de Bouça da Cova da Moura se trouve sur un plateau faisant face au Rio Leça. On y a identifié des tertres funéraires du Néolithique, auxquels sont associés des zones de concentration d’artefacts, incluant céramiques campaniformes, idoles et mobilier métallique. S’agissant de mobilier de surface, le contexte de ces différentes concentrations n’a pas été déterminé avec attention. Un autre fait significatif est l’apparition de gravures rupestres préhistoriques. On peut considérer le plateau comme un espace publique, qui s’est bâti physiquement et conceptuellement au cours des temps. Son importance et sa signification ont certainement été créées et transmises à travers un certain nombre de pratiques de construction mémorielle, représentatives de l’identité culturelle et de la cohésion sociale

Space of memory and representation: Bouça da Cova da Moura (Ardegães, Maia, Northwest of Portugal): a case study

Bouça da Cova da Moura is the local place-name attributed to a stretch of a plateau overlooking the Leça valley. Here, Neolithic burial mounds share their landscape setting with scatters of archaeological materials that include Bell Beaker fragments, idols and metalwork. Since these are mostly surface findings, their contexts have not yet been accurately determined. Another significant feature is the presence of prehistoric rock carvings. The plateau may thus be considered a public space, conceptually and physically built over time. Its significance and meanings were certainly created and transmitted through practices of memory construction which are representative of cultural identity and social cohesion.Le site de Bouça da Cova da Moura se trouve sur un plateau faisant face au Rio Leça. On y a identifié des tertres funéraires du Néolithique, auxquels sont associés des zones de concentration d’artefacts, incluant céramiques campaniformes, idoles et mobilier métallique. S’agissant de mobilier de surface, le contexte de ces différentes concentrations n’a pas été déterminé avec attention. Un autre fait significatif est l’apparition de gravures rupestres préhistoriques. On peut considérer le plateau comme un espace publique, qui s’est bâti physiquement et conceptuellement au cours des temps. Son importance et sa signification ont certainement été créées et transmises à travers un certain nombre de pratiques de construction mémorielle, représentatives de l’identité culturelle et de la cohésion sociale.info:eu-repo/semantics/publishedVersio

A Constrained ICA-EMD Model for Group Level fMRI Analysis

Independent component analysis (ICA), being a data-driven method, has been shown to be a powerful tool for functional magnetic resonance imaging (fMRI) data analysis. One drawback of this multivariate approach is that it is not, in general, compatible with the analysis of group data. Various techniques have been proposed to overcome this limitation of ICA. In this paper, a novel ICA-based workflow for extracting resting-state networks from fMRI group studies is proposed. An empirical mode decomposition (EMD) is used, in a data-driven manner, to generate reference signals that can be incorporated into a constrained version of ICA (cICA), thereby eliminating the inherent ambiguities of ICA. The results of the proposed workflow are then compared to those obtained by a widely used group ICA approach for fMRI analysis. In this study, we demonstrate that intrinsic modes, extracted by EMD, are suitable to serve as references for cICA. This approach yields typical resting-state patterns that are consistent over subjects. By introducing these reference signals into the ICA, our processing pipeline yields comparable activity patterns across subjects in a mathematically transparent manner. Our approach provides a user-friendly tool to adjust the trade-off between a high similarity across subjects and preserving individual subject features of the independent components

Clustering evoked potential signals using subspace methods

This work proposes a clustering technique to analyze evoked potential signals. The proposed method uses an orthogonal subspace model to enhance the single-trial signals of a session and simultaneously a subspace measure to group the trials into clusters. The ensemble averages of the signals of the different clusters are compared with ensemble averages of visually selected trials which are free of any artifact. Preliminary results consider recordings from an occipital channel where evoked response P100 wave is most pronounced.info:eu-repo/semantics/publishedVersio

Frequency-Resolved Dynamic Functional Connectivity Reveals Scale-Stable Features of Connectivity-States

Investigating temporal variability of functional connectivity is an emerging field in connectomics. Entering dynamic functional connectivity by applying sliding window techniques on resting-state fMRI (rs-fMRI) time courses emerged from this topic. We introduce frequency-resolved dynamic functional connectivity (frdFC) by means of multivariate empirical mode decomposition (MEMD) followed up by filter-bank investigations. In general, we find that MEMD is capable of generating time courses to perform frdFC and we discover that the structure of connectivity-states is robust over frequency scales and even becomes more evident with decreasing frequency. This scale-stability varies with the number of extracted clusters when applying k-means. We find a scale-stability drop-off from k = 4 to k = 5 extracted connectivity-states, which is corroborated by null-models, simulations, theoretical considerations, filter-banks, and scale-adjusted windows. Our filter-bank studies show that filter design is more delicate in the rs-fMRI than in the simulated case. Besides offering a baseline for further frdFC research, we suggest and demonstrate the use of scale-stability as a possible quality criterion for connectivity-state and model selection. We present first evidence showing that connectivity-states are both a multivariate, and a multiscale phenomenon. A data repository of our frequency-resolved time-series is provided

Pilot project on the implementation of FoodEx2 as part of the Standard Sample Description for the electronic transmission of harmonised chemical occurrence data to EFSA (NP/EFSA/DCM/2012/03/01)

Relatório Final do ProjetoEFSA supporting publication 2013:EN-454 (External Scientific Report)EFSA's Working Group on Food Classification launched in late 2011 the first version of a new and more comprehensive classification and description system for food and feed suitable for exposure assessment in different areas of food safety which was designated FoodEx2. Before being fully implemented, FoodEx2 needs to be tested in different applications, and commented on by users at national level and consequently be improved. Thus, in parallel to the development and implementation of the ‟CFP/EFSA/DATEX2011/01 - Implementation of Electronic Transmission of Chemical Occurrence Data in Portugal‟ project, INSA submitted an offer to the tender „Pilot projects on the implementation of FoodEx2 as part of the Standard Sample Description for the electronic transmission of harmonised chemical occurrence data to EFSA‟. Foodex2 system consists of a large number of individual food items, representing the minimum level of detail necessary to code/describe a food and feed sample to estimate dietary exposure, aggregated in groups and broader categories of food in a hierarchical structure like „parent-child‟ relationship. This characterization is improved with the use of facets. The term facet refers to a set of descriptors which allow detailing the characteristics of a food product according to various aspects such as physical state or preservation technique, among others. These activities of this project performed by INSA in the period October 2012-April 2013 are summarised in the present report.EFS