803 research outputs found

    Height after side: Goalkeepers detect the vertical direction of association-football penalty kicks from the ball trajectory

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    The present research analyzes the relation between the height of penalty kicks in association football and (a) the probability that goalkeepers stop the ball, (b) the kinematics of the kicker, and (c) the movements of the goalkeeper. We re-analyzed movement registration data that were collected in an experiment (with professional and semi-professional players) that focused on the horizontal direction of the penalties (Lopes et al., 2014). We also digitized and analyzed regular videos of the goalkeepers that were recorded by Lopes et al. (2014) but not analyzed. The present research complements the current understanding of the penalty kick with three main observations. First, goalkeepers save penalties at middle heights more often than low and high penalties. Second, the height of penalties is predicted less clearly than their horizontal direction from the kinematics of penalty takers. Third, goalkeepers tend to initiate the horizontal component of the saving action before the penalty taker contacts the ball, but they initiate the vertical component of the action about 245 ms after the contact. Taken together, these results support the view that goalkeepers make the left-right decision at least partly focusing on the kinematics of the kicker, and that they dynamically decide the vertical aspects of the movement later, focusing on the ball trajectory.This research was supported by a grant from the Portuguese Foundation for Science and Technology (SFRH/BD/60520/2009), awarded to JL, and a grant from the Spanish Ministry of Economy and Competitiveness (PSI2013-43742). DA was partly supported by the Fundação para a Ciência e Tecnologia, under Grant UIDB/00447/2020 to CIPER – Centro Interdisciplinar para o Estudo da Performance Humana (unit 447)

    Generating human-like movements on an anthropomorphic robot using an interior point method

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    In previous work we have presented a model for generating human-like arm and hand movements on an anthropomorphic robot involved in human-robot collaboration tasks. This model was inspired by the Posture-Based Motion-Planning Model of human movements. Numerical results and simulations for reach-to-grasp movements with two different grip types have been presented previously. In this paper we extend our model in order to address the generation of more complex movement sequences which are challenged by scenarios cluttered with obstacles. The numerical results were obtained using the IPOPT solver, which was integrated in our MATLAB simulator of an anthropomorphic robot.EU funded Project PF7 Marie Curie ``NETT - Neural Engineering Transformative Technologies'', by FEDER funds through COMPETE (Operational Programme Thematic Factors of Competitiveness) and by portuguese funds through FCT (Foundation for Science and Technology) within the projects PEst-C/MAT/UI0013/2011 and FCOMP-01-0124-FEDER-022674

    Organic matter sources for tidal marsh sediment over the past two millennia in the Minho River estuary (NW Iberian Peninsula)

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    Environmental changes during the last 2 millennia in the Minho River tidal marsh (NW Portugal-Spain border) were reconstructed. Changes in the sources of organic matter (OM) delivered to the marsh were evaluated from elemental, isotopic and molecular composition using a 1 m sediment core. Carbon isotopic composition (delta13C) and organic carbon to total nitrogen ratio (Corg/N) provided valuable information concerning the origin of the OM. These parameters indicated a major input from land plants, reaching a maximum at 1100–1200 and 1750–1850 AD. These periods match with major flood events in the NW of the Iberian Peninsula, as reported by several authors. A significant reduction in the terrestrial signature occurred at 6–4 cm (ca. 1960–1985 AD), which is contemporaneous with the construction of several major dams on the Minho River. The distribution of selected lipid biomarkers, including n-alkanes, n-fatty acids and n-alkan-2-ones and specific parameters derived from the molecular distributions, were useful for refining bulk geochemical results. Long chain n- alkanes with an odd number of carbons are indicators of soil-and vascular plant derived terrestrial OM and were dominant throughout the core. In addition, a greater contribution of plankton-derived lipids was observed in the sections corresponding to ca. 1960–1985 AD (6–4 cm) and ca. 100–200 AD (96–94 cm). Although different degradation rates for individual compounds might have partly affected biomarker assemblages, the variations could be attributed to a sharp decrease in the freshwater contribution to the Minho River Estuary (dam construction) and a possible marine highstand, respectively. In addition, several parameters suggested changes in land use (including deforestation and farming) and probably the effects of mining exploitation during the Roman occupation of the area.We acknowledge the funding by the Foundation for Science and Technology (FCT) of Portugal for J.M. M’s PhD. Grant (SFRH/BD/45528/2008) and for the WestLog Project (PTDC/CTE-GIX/105370/2008). E.L. was awarded a Ralph E. Powe Junior Faculty Enhancement Award. This is a contribution to the IGCP Project 588 and to the Geo-Q Research Unit (Aranzadi).Peer reviewe

    COSMO-RS Selection and Solubility Experiments

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    Funding Information: This work was also supported by Associate Laboratory for Green Chemistry–LAQV, financed by national funds from FCT/MCTES (UID/QUI/50006/2020), the contracts of Individual Call to Scientific Employment Stimulus 2020.00835.CEECIND (J.M.M.A.)/2021.01432.CEECIND (A.B.P.) and by FCT/MCTES (Portugal) through the project PTDC/EQU-EQU/29737/2017. The authors thank Solvay for providing the ionic liquid tri(butyl) ethylphosphonium diethylphosphate. M.C.G. and J.A. thank IDEX-LYON for financial support (Programme Investissement d’Avenir ANR-16-IDEX-0005). Publisher Copyright: © 2022 American Chemical Society. All rights reserved.In recent years, the fight against climate change and the mitigation of the impact of fluorinated gases (F-gases) on the atmosphere is a global concern. Development of technologies that help to efficiently separate and recycle hydrofluorocarbons (HFCs) at the end of the refrigeration and air conditioning equipment life is a priority. The technological development is important to stimulate the F-gas capture, specifically difluoromethane (R-32) and 1,1,1,2-tetrafluoroethane (R-134a), due to their high global warming potential. In this work, the COSMO-RS method is used to analyze the solute-solvent interactions and to determine Henry's constants of R-32 and R-134a in more than 600 ionic liquids. The three most performant ionic liquids were selected on the basis of COSMO-RS calculations, and F-gas absorption equilibrium isotherms were measured using gravimetric and volumetric methods. Experimental results are in good agreement with COSMO-RS predictions, with the ionic liquid tributyl(ethyl)phosphonium diethyl phosphate, [P2444][C2C2PO4], being the salt presenting the highest absorption capacities in molar and mass units compared to salts previously tested. The other two ionic liquids selected, trihexyltetradecylphosphonium glycinate, [P66614][C2NO2], and trihexyl(tetradecyl)phosphonium 2-cyano-pyrrole, [P66614][CNPyr], may be competitive as far as their absorption capacities are concerned. Future works will be guided on evaluating the performance of these ionic liquids at an industrial scale by means of process simulations, in order to elucidate the role in process efficiency of other relevant absorbent properties such as viscosity, molar weight, or specific heat.publishersversionpublishe

    Sorption of fluorinated greenhouse gases in silica-supported fluorinated ionic liquids

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    the contracts of Individual Call to Scientific Employment Stimulus 2020.00835.CEECIND (J.M.M.A.) / 2021.01432.CEECIND (A.B.P.), the Norma Transitória DL 57/2016. Publisher Copyright: © 2022 The Authors.The Kigali Amendment to the Montreal Protocol limits the global use of fluorinated greenhouse gases (F-gases) and encourages the development of a new generation of refrigerants with lower global warming potential. Therefore, there is a need to develop efficient and sustainable technologies to selectively capture and recycle the F-gases as new environmentally sustainable refrigerants. Here, ionic liquids (ILs) with high F-gas uptake capacity and selectivity were supported on silica and their potential as media for selective F-gas sorption was studied. For this purpose single-component sorption equilibria of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a) were measured at 303.15 K by gravimetry. The sorption data were successfully correlated using classical models of sorption thermodynamics. The results show that the IL supported in the porous volume and on the external surface of the porous silica controls the F-gas uptake in the composites and that changing the IL's cations and anions allows fine-tuning the selectivity of the sorption process. This work brings crucial knowledge for the development of new materials based on ILs for the selective sorption of F-gases.publishersversionpublishe

    Absorption of Fluorinated Greenhouse Gases Using Fluorinated Ionic Liquids

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    funding of the KET4F-Gas project, SOE2/P1/P0823, co -funded by the Interreg Sudoe Programme through the European Regional Development Fund (ERDF). FCT/MCTES for financial support through IF/00190/2014 , IF/00210/2014 financial support through the Norma TransitOria DL 57/2016 Program Contract (FCT/MCTES). FCT/MCTES (UID/QUI/50006/2019).The increasing awareness of the environmental impact of fluorinated gases (F-gases) used in refrigeration is instigating the development of technologies to recover and recycle them. With this goal in mind, single-component absorption equilibrium isotherms at 303.15 K of F-gases in different ionic liquids (ILs) were determined using a gravimetric method. The selected F-gases are the most used in domestic refrigeration (R-32: difluoromethane, R-125: pentafluoroethane, and R-134a: 1,1,1,2-tetrafluoroethane). The results show that ILs containing a fluorinated alkyl side chain with four carbon atoms, that is, fluorinated ILs (FILs), have higher gas absorption capacity than conventional fluoro-containing ILs. All studied ILs showed ideal selectivity toward R-134a. Conventional fluoro-containing ILs showed better selectivities for the separation of the binary mixtures R-134a/R-125 and R-32/R-125, and FILs showed better selectivities for the R-134a/R-32 mixture. These results provide fundamental knowledge of the behavior of these new alternative solvents and key information for their application in the separation of F-gas mixtures of commercial refrigerants.authorsversionpublishe

    Exploring the Potential of Metal–Organic Frameworks for the Separation of Blends of Fluorinated Gases with High Global Warming Potential

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    Funding Information: The authors acknowledge the financial support from the LIFE‐4‐Fgases project, LIFE20 CCM/ES/001748, funded by EU LIFE Programme. This work was also financed by national funds from FCT/MCTES (Portugal) through Associate Laboratory for Green Chemistry–LAQV (UIDB/50006/2020 | UIDP/50006/2020), the contracts of Individual Call to Scientific Employment Stimulus 2020.00835.CEECIND (J.M.M.A.)/2021.01432.CEECIND (A.B.P.), and the Norma Transitória DL 57/2016 Program Contract (R.P.P.L.R.). Publisher Copyright: © 2022 The Authors. Global Challenges published by Wiley-VCH GmbH.The research on porous materials for the selective capture of fluorinated gases (F-gases) is key to reduce their emissions. Here, the adsorption of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a) is studied in four metal–organic frameworks (MOFs: Cu-benzene-1,3,5-tricarboxylate, zeolitic imidazolate framework-8, MOF-177, and MIL-53(Al)) and in one zeolite (ZSM-5) with the aim to develop technologies for the efficient capture and separation of high global warming potential blends containing these gases. Single-component sorption equilibria of the pure gases are measured at three temperatures (283.15, 303.15, and 323.15 K) by gravimetry and correlated using the Tóth and Virial adsorption models, and selectivities toward R-410A and R-407F are determined by ideal adsorption solution theory. While at lower pressures, R-125 and R-134a are preferentially adsorbed in all materials, at higher pressures there is no selectivity, or it is shifted toward the adsorption R-32. Furthermore, at high pressures, MOF-177 shows the highest adsorption capacity for the three F-gases. The results presented here show that the utilization of MOFs, as tailored made materials, is promising for the development of new approaches for the selective capture of F-gases and for the separation of blends of these gases, which are used in commercial refrigeration.publishersversionepub_ahead_of_prin

    A percepção dos profissionais do Centro de Atenção Psicossocial álcool e drogas do município de Anápolis sobre a assistência prestada ao dependente químico

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    Objetivo: analisar a assistência ao usuário de drogas no Centro de Atenção Psicossocial álcool e drogas, identificar a percepção dos profissionais sobre a estrutura física e assistência prestada aos usuários e analisar o perfil de atuação dos profissionais desse. Método: Trata-se de um estudo de campo, prospectivo, transversal, exploratório, descritivo de abordagem qualitativa. A população e a amostra foram os profissionais do Centro de Atenção Psicossocial álcool e drogas. As entrevistas foram analisadas a partir de pré-categorias de análise. Resultados: Observou-se que os profissionais desse local são na maioria mulheres com idade média 32 anos. Na opinião da maioria dos entrevistados o Centro de Atenção Psicossocial álcool e drogas têm estrutura e ambientes favoráveis para a assistência aos usuários de álcool e drogas, no entanto, apontam alguns problemas e dificuldades no atendimento, entre estes: falta de suporte governamental para a capacitação e qualificação da equipe da unidade, baixa adesão dos usuários ao tratamento e a pouca informação da população em geral sobre a existência do Centro de Atenção na cidade de Anápolis. Conclusão: Opina-se que esta pesquisa, ao produzir tais informações, poderá contribuir com o município, na melhoria da estruturação do Centro de Atenção Psicossocial álcool e drogas, como um componente importante para a conformação da rede substitutiva em saúde mental de Anápolis
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