881 research outputs found

    Microstructure, composition and their relationship with molecular mobility, food quality and stability

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    Food stability is a critical parameter for both consumers and producers, since it assures safety, nutritional, and sensorial quality of foodstuffs, and at the same time maximizes shelf-life. For a long time, water activity, aw, was considered a determinant parameter in food stability and physical properties. This concept was challenged with the revolutionary approach to the study of food systems using the glass transition concept. Recently, scientific research suggests that molecular mobility is a fundamental approach to fully attain food physical properties and stability. Current literature suggests that stability can only be fully grasped if molecular mobility and structure are taken into consideration; that is, an appropriate understanding of the behavior of food products requires knowledge of its composition, structure, and molecular dynamics, through the three-dimensional arrangement of the various structural elements and their interactions. Food systems are complex mixtures of water, biopolymers, low-molecular weight ingredients, and colloid particles, and the molecular mobility between these different components reflects on the stability of such systems, determining the physical state, microstructure, and composition, which impacts food characteristics. Particularly, food water content, location, and interactions with other components are critical in microbial growth, degradation reactions, and sensorial aspects. Understanding changes in water location and mobility represents a significant step in food stability knowledge, once that water availability profoundly affects chemical, physical, and microbiological quality of foods.info:eu-repo/semantics/acceptedVersio

    O Comportamento do Investidor é Influenciado por Fatores Psicológicos? Evidência Empírica no Mercado Português

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    No âmbito da teoria financeira tradicional os investidores são considerados racionais. No contexto das finanças comportamentais, os investidores tendem a afastar-se do princípio da racionalidade, já que as suas decisões se baseiam mais em fatores psicológicos do que em princípios de gestão de investimentos. Este trabalho pretende analisar se alguns dos comportamentos descritos pelas finanças comportamentais afetam a tomada de decisão de um grupo de investidores portugueses, inquirindo um conjunto de 300 indivíduos residentes no território nacional. Os resultados indicam que o comportamento dominante é o de aversão ao risco. Os indivíduos inquiridos manifestam alguma preferência por investimentos em títulos nacionais, o que indicia alguma evidência de patriotismo. Foi igualmente encontrada evidência de comportamentos de aversão a perdas, unidimensionalidade das atitudes face ao risco e excesso de confiança. Os resultados permitem concluir que os investidores cometem alguns erros cognitivos, afastando-se do conceito de racionalidade defendido pelas finanças tradicionais

    Physical Exercise Program on Fall Prevention Using Technological Interface: Pretest Study

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    Background: Prevention of falls among older adults has boosted the development of technological solutions, requiring testing in clinical contexts and robust studies that need prior validation of procedures and data collection tools. Objective: The objectives of our study were to test the data collection procedure, train the team, and test the usability of the FallSensing Games app by older adults in a community setting. Methods: This study was conducted as a pretest of a future pilot study. Older adults were recruited in a day care center, and several tests were applied. Physical exercise sessions were held using the interactive FallSensing Games app. Nurse training strategies was completed. Results: A total of 11 older adults participated. The mean age was 75.08 (SD 3.80) years, mostly female (10/11, 91%) and with low (3-6 years) schooling (10/11, 91%). Clinically, the results show a group of older adults with comorbidities. Cognitive evaluation of the participants through the Mini Mental State Examination showed results with an average score of 25.64 (SD 3.5). Functional capacity assessed using the Lawton Instrumental Activities of Daily Living Scale (overall score from 0-23, with lower scores reflecting worse capacity to perform activities) showed impairment in different instrumental activities of daily living (average score 14.27). The data collection tool proved to enable easy interpretation; however, its structure needed small adjustments to facilitate the data collection process. Despite the length of the questionnaire, its implementation took an average of 21 minutes. For the assessment of the prevalence of fear of falling, the need to add a question was identified. The performance of functional tests under the guidance and presence of rehabilitation nurses ensured the safety of the participants. The interactive games were well accepted by the participants, and the physical exercises allowed data collection on the functionality of the older adults, such as the number of repetitions in the tests, range of movement (angle), duration of the movements, and execution of each cycle. Concerning the training of the nurses, it was crucial that they had experience with the platform, specifically the position of the chair facing the platform, the position of the feet, the posture of participants, and the use of sensors. Conclusions: In the future pilot study, the researchers point out the need to design a study with mixed methods (quantitative and qualitative), thus enriching the study results.info:eu-repo/semantics/publishedVersio

    The CSPP impact on non-financial firms’ cost of borrowing and debt choice

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    In this study, we examine the impact of the European Central Bank’s (ECB) corporate sector purchase programme (CSPP) on euro area non-financial firms’ cost of borrowing and choice between bank and public debt. Using a large sample of corporate bonds and syndicated loans closed between 2000 and 2019, we find that the CSPP reduced corporate bond spreads significantly, in both announcement and implementation periods. Findings also suggest that the CSPP had a positive spillover effect into the syndicated loan market during the implementation period. Our results show that there is a substitution effect between eligible bonds and equivalent loans, with non-financial firms choosing to use more corporate bonds than syndicated loan deals after the CSPP announcement, and that this effect is more important for non-switchers, those that may have more difficulty in accessing the bond market. Finally, we provide evidence that, when controlling for the CSPP, borrowers that choose corporate bonds are larger, more profitable, and have larger growth opportunity sets; and switchers with high agency costs of debt prefer bank debt.info:eu-repo/semantics/publishedVersio

    A Technological-Based Platform for Risk Assessment, Detection, and Prevention of Falls Among Home-Dwelling Older Adults: Protocol for a Quasi-Experimental Study

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    Background: According to the United Nations, it is estimated that by 2050, the number of people aged 80 years and older will have increased by 3 times. Increased longevity is often accompanied by structural and functional changes that occur throughout an individual’s lifespan. These changes are often aggravated by chronic comorbidities, adopted behaviors or lifestyles, and environmental exposure, among other factors. Some of the related outcomes are loss of muscle strength, decreased balance control, and mobility impairments, which are strongly associated with the occurrence of falls in the elderly. Despite the continued undervaluation of the importance of knowledge on fall prevention among the elderly population by primary care health professionals, several evidence-based (single or multifaceted) fall prevention programs such as the Otago Exercise Program (OEP) have demonstrated a significant reduction in the risk of falls and fall-related injuries in the elderly within community settings. Recent studies have strived to integrate technology into physical exercise programs, which is effective for adherence and overcoming barriers to exercise, as well as improving physical functioning. Objective: This study aims to assess the impact of the OEP on the functionality of home-dwelling elderly using a common technological platform. Particularly, the impact on muscle strength, balance, mobility, risk of falling, the perception of fear of falling, and the perception of the elderly regarding the ease of use of technology are being examined in this study. Methods: A quasi-experimental study (before and after; single group) will be conducted with male and female participants aged 65 years or older living at home in the district of Porto. Participants will be recruited through the network COLABORAR, with a minimum of 30 participants meeting the study inclusion and exclusion criteria. All participants will sign informed consent forms. The data collection instrument consists of sociodemographic and clinical variables (self-reported), functional evaluation variables, and environmental risk variables. The data collection tool integrates primary and secondary outcome variables. The primary outcome is gait (timed-up and go test; normal step). The secondary outcome variables are lower limb strength and muscle resistance (30-second chair stand test), balance (4-stage balance test), frequency of falls, functional capacity (Lawton and Brody - Portuguese version), fear of falling (Falls Efficacy Scale International - Portuguese version), usability of the technology (System Usability Scale - Portuguese version), and environmental risk variables (home fall prevention checklist for older adults). Technological solutions, such as the FallSensing Home application and Kallisto wearable device, will be used, which will allow the detection and prevention of falls. The intervention is characterized by conducting the OEP through a common technological platform 3 times a week for 8 weeks. Throughout these weeks, the participants will be followed up in person or by telephone contact by the rehabilitation nurse. Considering the COVID-19 outbreak, all guidelines from the National Health Service will be followed. The project was funded by InnoStars, in collaboration with the Local EIT Health Regional Innovation Scheme Hub of the University of Porto. Results: This study was approved on October 9, 2020 by the Ethics Committee of Escola Superior de Enfermagem do Porto (ESEP). The recruitment process was meant to start in October, but due to the COVID-19 pandemic, it was suspended. We expect to restart the study by the beginning of the third quarter of 2021. Conclusions: The findings of this study protocol will contribute to the design and development of future robust studies for technological tests in a clinical context.info:eu-repo/semantics/publishedVersio

    ASBGO*: a mechatronic improved smart walker

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    The ASBGo* Smart Walker (SW) is a research project from the Adapative System Behaviour Group. This device is used as a medical solution for rehabilitation of patients with gait disorders. To meet the user’s needs this device was designed and developed into an improved and reliable system from both mechanic and electronic point of view. Thereby, in this paper a brief outline of the smart walker’s system and design architecture will be presented

    Transnational banking supervision and resilience: the SSM case

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    In this letter we assess the impact of adopting a transnational supervisor on the resilience of large and complex banks, exploring the establishment of the Single Supervisory Mechanism (SSM) in 2014. Using a differences-in-differences approach, we compare the performance of SSM banks vis-à-vis other banks with a similar size and complexity. Our results suggest that the adoption of a transnational supervisor can improve the resilience of large and complex banks, particularly for those operating in countries with larger banking sectors, higher market concentration and higher supervisory discretion.info:eu-repo/semantics/publishedVersio

    Tensión de adhesión de revestimientos cerámicos obtenidos por proyección robótica a llama

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    Introduction: One of the possible applications of ceramic thermal barriers is in shells (permanent moulds – die casting). The moulds` capacity to support very high temperatures (up to 1600 °C) plays a crucial role in the selection of materials due to the liquid state of the cast iron. Objectives: This paper presents and discusses the obtained results from robotic flame projection tests, carried out with the purpose to quantify the influence of several factors of flame sprayed in the adhesion strength of coatings of Nickel-Aluminium Molybdenum and Zirconium Oxide. In literature a minimum adhesion strength was not found for the application of thermal ceramic barriers in the coating of permanent casting moulds, so in this work it is intended to obtain its values considering several combinations of projection parameters and substrates. Methods: The determination of the adhesion strength was performed according to the standard ASTM C633-79 where the coated test specimens were glued to CK45 steel against-specimens with a cyanoacrylate glue (LOCTITE 415). A weight of 100 N was then applied for 3 minutes to promote the initiation of the polymerization reaction of the cyanoacrylates and a period of 24 hours was needed so the bonded glue could acquire its maximum strength (sufficient enough to tear off the coating of the specimen). Finally tensile tests were carried out at the speed of 1 mm/min. Results: The main parameters studied are the material of the substrate, the projection angle and the substrate preheating temperature. The higher adhesion strength for the sprayed to 90° (average value of 6.2 MPa) was obtained by the specimens of spheroidal graphite cast iron (SGCI) with a preheating temperature of 120 °C. For the preheating of 90 °C and spray angle of 90° the aluminum-copper (AlCu) and brass specimens were the ones that obtained the higher adhesion strengths (average value of 4.5 MPa). The sprayed of 65° originates the higher adhesion strength in all the materials used for the substrate, being the highest value (average value of 8.3 MPa) obtained by the spheroidal graphite cast iron. Conclusions: The results obtained clearly suggest that the substrate material and the preheating temperature strongly influence the adhesion strength. The analysis of the coatings microstructures, using optical microscopy, supports this observation.Introdução: Uma das possíveis aplicações de barreiras térmicas cerâmicas é no revestimento de moldes permanentes para fundição. A capacidade do molde suportar temperaturas muito elevadas (até 1600 °C), devido ao estado líquido do ferro fundido, desempenha um papel crucial na seleção de materiais. Objetivos: Este artigo apresenta e discute os resultados obtidos a partir de testes de projeção robótica à chama, com o objetivo de quantificar a influência de vários fatores da projeção à chama na tensão de adesão de revestimentos de Níquel-Alumínio Molibdênio e Óxido de Zircónia. Na literatura não foi encontrada uma tensão mínima de adesão requerida para a aplicação de barreiras térmicas cerâmicas no revestimento de moldes permanentes para fundição, assim, no trabalho apresentado neste artigo, pretende-se obter seus valores considerando várias combinações de parâmetros de projeção e substratos. Métodos: A determinação da tensão de adesão foi realizada de acordo com a norma ASTM C633-79 em que os provetes revestidos foram colados a contra-provetes de aço CK45 grenalhados, com uma cola à base de cianoacrilatos (LOCTITE 415). De seguida aplicou-se um peso de 100 N durante 3 minutos para a força de compressão promover o início da reação de polimerização dos cianoacrilatos e aguardou-se 24 horas para que a junta colada tivesse tempo de adquirir a resistência máxima (o suficiente para arrancar o revestimento do provete). Realizaram-se depois ensaios de tração à velocidade de 1 mm/min. Resultados: Os principais parâmetros estudados foram o material do substrato, o ângulo de projeção e a temperatura de pré aquecimento do substrato. A maior força de adesão para a projeção a 90° (média de 6,2 MPa) foi obtida com os provetes de ferro fundido com grafite esferoidal (SGCI) com uma temperatura de pré-aquecimento de 120 ° C. Para o pré-aquecimento de 90 °C e ângulo de projeção de 90°, foram os provetes de duralumínio (AlCu) e de latão que obtiveram as maiores forças de adesão (média de 4,5 MPa). A projeção a 65 ° origina a maior tensão de adesão em todos os materiais utilizados para o substrato, sendo o maior valor (média de 8,3 MPa) obtido pelo ferro fundido de grafite esferoidal. Conclusões: Os resultados obtidos sugerem claramente que o material do substrato e a temperatura de pré-aquecimento influenciam fortemente a tensão de adesão. A análise das microestruturas dos revestimentos, utilizando microscopia ótica, comprova esta observação.Introducción: Una de las posibles aplicaciones de barreras térmicas cerámicas es en el revestimiento de moldes permanentes para fundición. La capacidad del molde para soportar temperaturas muy altas (hasta 1600 °C), debido al estado líquido del hierro fundido, desempeña un papel crucial en la selección de materiales. Objetivos: Este artículo presenta y discute los resultados obtenidos a partir de pruebas de proyección robótica a la llama, con el objetivo de cuantificar la influencia de varios factores de la proyección a la llama en la resistencia a la adhesión de revestimientos de Niquel-Aluminio-Molibdeno y Óxido de Zirconia. En la literatura no se encontró una tensión mínima de adhesión requerida para la aplicación de barreras térmicas cerámicas en el revestimiento de moldes permanentes para fundición, así en el trabajo presentado en este artículo, se pretende obtener sus valores considerando varias combinaciones de parámetros de proyección y sustratos. Métodos: La determinación de la tensión de adhesión se realizó de acuerdo con la norma ASTM C633-79 en la que se probaron las probetas revestidas a contra-probetas de acero CK45 gralladas, con un pegamento a base de cianoacrilatos (LOCTITE 415). A continuación se aplicó un peso de 100 N durante 3 minutos para la fuerza de compresión promover el inicio de la reacción de polimerización de los cianoacrilatos y se aguardó 24 horas, para que la junta adhesiva tuviera tiempo de adquirir la resistencia máxima (suficiente para arrancar el revestimiento de la probeta). Se realizaron después los ensayos de tracción a velocidad de 1 mm/min. Resultados: Los principales parámetros estudiados son el material del sustrato, el ángulo de proyección y la temperatura de precalentamiento del sustrato. La mayor fuerza de adhesión para la proyección a 90° (media de 6,2 MPa) fue obtenida con las probetas de hierro fundido con grafito esferoidal (SGCI) con una temperatura de precalentamiento de 120 °C. Para el precalentamiento de 90 °C y ángulo de proyección de 90°, fueron las probetas de duraluminio (AlCu) y de latón que obtuvieron las mayores fuerzas de adhesión (media de 4,5 MPa). La proyección a 65° origina la mayor tensión de adhesión en todos los materiales utilizados para el sustrato, siendo el mayor valor (media de 8,3 MPa) obtenido por el hierro fundido de grafito esferoidal. Conclusiones: Los resultados obtenidos sugieren claramente que el material del sustrato y la temperatura de precalentamiento influyen fuertemente en la fuerza de adhesión. El análisis de las microestructuras de los revestimientos, utilizando microscopia óptica, comprueba esta observación

    Adhesion to and viability of Salmonella Enteritidis on food contact surfaces

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    Bacterial adhesion to food contacting surfaces

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    Contamination of kitchen surfaces, during food preparation, due to bacteria present in foodstuff is one of the main causes of foodborne outbreaks. Cells adhered to those surfaces of domestic kitchens are not easily removed by normal cleaning procedures. Therefore, they can be a source of contamination for other foods and objects. Several studies indicate that various pathogenic bacteria like Listeria monocytogenes, Salmonella spp., Campylobacter, E. coli and Staphylococcus aureus survive in kitchen utensils, hands and in bench cover materials. In this way it is of utmost importance to know the factors responsible for the adhesion of pathogenic bacteria to kitchen materials in order to select the material less prone to bacterial colonization. Accordingly, this chapter will focus on the study of the adhesion of strains of Listeria monocytogenes and Salmonella enteritidis to materials commonly used in kitchens (stainless steel 304, marble, granite, glass, polypropylene from a bowl and a cutting board and two kinds of silestone).Portuguese Science Foundation (FCT
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