344 research outputs found

    Luxury hotel types: Examining the effects of (in)conspicuous consumption orientation on luxury hotels’ valuations

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    The present research aims to examine how conspicuous consumption orientation impacts consumers’ valuations of luxury hotel types – subtle versus extravagant. Two experimental studies were performed and results show that indeed conspicuous consumption orientation moderates the relationship between luxury hotel type and consumers’ enjoyment and quality perceptions. Also their likelihood of staying and willingness to pay for a hotel. Specifically, results show that low conspicuous-oriented individuals seem to value more subtle than extravagant luxury hotels. Yet, for high conspicuous-oriented individuals no significant differences are observed when exposed to either hotel types. Our findings further suggest that, overall, there are greater sustainability expectations towards hotels that provide more subtle and inconspicuous hotel experiences than hotels that provide more extravagant and conspicuous experiences. Theoretical and managerial implications are provided.info:eu-repo/semantics/publishedVersio

    Hydrogels based on poly(vinyl alcohol) for cartilage substitution

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    Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

    Developing statistical literacy: Student learning and teacher education

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    Recent international and national mathematics curriculum guidelines indicate the development of students’ statistical literacy, at different levels of schooling, as a major educational aim. In Portugal, the mathematics syllabus for basic education, which began to be implemented in 2009, gave a greater emphasis on statistics, presenting more demanding learning goals, since the elementary levels. This represented a challenging situation for practicing teachers, requiring them to develop new perspectives about the teaching and learning of statistics. In this context, the project Developing statistical literacy: Student learning and teacher education was planned aiming to study the development of statistical literacy from elementary to secondary education, with special attention to two main issues: i) the characterization of key aspects of students’ statistical literacy, particularly regarding the ability to formulate questions, collect data and represent them to answer those questions, and ii) the development of statistical and didactical knowledge for teaching in different schools levels. As the project unfolded, another research strand associated with students’ statistical reasoning and the necessary conditions for its development emerged

    Dynamic ground stress‐path evolution due to the railway traffic: A parametric study

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    No presente artigo apresenta‐se um estudo numérico sobre a evolução do estado de tensão geomecânico induzido pela passagem de tráfego ferroviário. O modelo numérico proposto é baseado na formulação 2,5D apoiada no MEF‐PML, permitindo a consideração da interação do sistema composto pelo comboio, via‐férrea e maciço de fundação. Para o caso de estudo proposto, as alterações do estado de tensão são sistematizadas sob a forma de trajetórias de tensão. Perante os resultados alcançados é possível reconhecer a grande influência da velocidade de circulação do comboio e da presença de irregularidades na via no comportamento da via‐férrea. Tirando partido dos conhecimentos adquiridos com a realização dos estudos paramétricos referidos, verifica‐se a adequabilidade de um ensaio laboratorial –ensaio torsional com cilindro vazado– na simulação das complexas trajetórias de tensão induzidas no solo de fundação pela passagem do tráfego ferroviário. Os resultados obtidos permitem perspetivar a simulação em laboratório dessa ação, através de um carregamento cíclico, com o objetivo de estudar a acumulação de dano nas amostras.In this paper, a numerical study of the geomechanical stress state evolution induced by the railway traffic is presented. The numerical model is based on a 2.5D formulation with the ability to account for the dynamic train‐track interaction. For the case study, the stress state evolution is systematized in the form of stress paths. The results obtained allow to recognize the great influence of the train speed and the presence of irregularities in the track for the behavior of the railway track. Based on the knowledge acquired during the implementation of previous parametric studies, the adequacy of the hollow cylinder torsional test to simulate the complex stress paths induced in the ground of the traffic railway is evaluated. The results obtained allow to put in perspective the simulation of these loads in laboratory, with the aim of studying the damage accumulation in the specimens.Peer Reviewe

    ANALYSIS OF NOx EMISSIONS AND SPECIFIC FUEL CONSUMPTION OF A DIESEL ENGINE OPERATING WITH DIESEL/BIODIESEL BLENDS

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    This study aims to examine experimentally the NOx emissions and the performance of a motor AGRALE M90, single cylinder, operating with diesel and biodiesel blends. The engine was linked to an electric generator, which provided 1500 W, 3000 W and 4500 W to an electrical system. The engine was tested with fuel blends containing different amounts of commercial diesel (B4) with palm biodiesel (B100). NOx emissions, as well as the specific fuel consumption of diesel, biodiesel and their mixtures were measured and analyzed. In this study, emissions of NOx have been prioritized over other pollutants by environmental issues and techniques. Air pollution by NOx causes serious respiratory problems. Furthermore, emissions of NOx enable a qualitative assessment of the combustion process. The results show that the commercial diesel has better performance in terms of energy efficiency and NOx emissions

    About the sterilization of chitosan hydrogel nanoparticles

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    In the last years, nanostructured biomaterials have raised a great interest as platforms for delivery of drugs, genes, imaging agents and for tissue engineering applications. In particular, hydrogel nanoparticles (HNP) associate the distinctive features of hydrogels (high water uptake capacity, biocompatibility) with the advantages of being possible to tailor its physicochemical properties at nano-scale to increase solubility, immunocompatibility and cellular uptake. In order to be safe, HNP for biomedical applications, such as injectable or ophthalmic formulations, must be sterile. Literature is very scarce with respect to sterilization effects on nanostructured systems, and even more in what concerns HNP. This work aims to evaluate the effect and effectiveness of different sterilization methods on chitosan (CS) hydrogel nanoparticles. In addition to conventional methods (steam autoclave and gamma irradiation), a recent ozone-based method of sterilization was also tested. A model chitosan-tripolyphosphate (TPP) hydrogel nanoparticles (CS-HNP), with a broad spectrum of possible applications was produced and sterilized in the absence and in the presence of protective sugars (glucose and mannitol). Properties like size, zeta potential, absorbance, morphology, chemical structure and cytotoxicity were evaluated. It was found that the CS-HNP degrade by autoclaving and that sugars have no protective effect. Concerning gamma irradiation, the formation of agglomerates was observed, compromising the suspension stability. However, the nanoparticles resistance increases considerably in the presence of the sugars. Ozone sterilization did not lead to significant physical adverse effects, however, slight toxicity signs were observed, contrarily to gamma irradiation where no detectable changes on cells were found. Ozonation in the presence of sugars avoided cytotoxicity. Nevertheless, some chemical alterations were observed in the nanoparticles.info:eu-repo/semantics/publishedVersio

    Effect of chaethomellic acid on renal function in rat model of chronic renal failure

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    To study the effect of chronic treatment with chaethomellic acid (CA), a highly specific inhibitor of ras farnesyl-protein transferase, on the renal function of rats with renal failure induced by renal mass reduction. Male Wistar rats were subjected to 5/6 nephrectomy (RMR) or sham-operated (SO). One week after surgery, rats have been placed in four experimental groups: RMR: rats without treat- ment (n=13); RMR+CA: rats treated with CA (n=13); SO: rats without treatment (n=13); SO+AC: rats treated with CA (n=13). CA was intraperitoneally administered in a dose of 0.23 g/Kg three times a week for 6 months. Creatinine, blood urea nitrogen (BUN) and protein were measured in serum and/or urine by routine laboratory techniques. BUN, creatinine, and proteinuria were significantly lower and creatinine clearance was significantly higher in SO and SO+AC groups when compared with RMR and RMR+AC groups. There were no differ- ences in creatinine, proteinuria and creatinine clearance between RMR and RMR+AC groups. Anyway, RMR+AC group showed significant lower BUN and lower creatinine and proteinuria, and higher creatinine clearance than RMR group. In a model of renal failure induced by RMR, 6 months of treatment with CA may have some beneficial effect on renal function

    Effect of chaethomellic acid on renal function in a rat model of chronic renal failure

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    To study the effect of chronic treatment with chaethomellic acid (CA), a highly specific inhibitor of ras farnesyl-protein transferase, on the renal function of rats with renal failure induced by renal mass reduction. Male Wistar rats were subjected to 5/6 nephrectomy (RMR) or sham-operated (SO). One week after surgery, rats have been placed in four experimental groups: RMR: rats without treat- ment (n=13); RMR+CA: rats treated with CA (n=13); SO: rats without treatment (n=13); SO+AC: rats treated with CA (n=13). CA was intraperitoneally administered in a dose of 0.23 g/Kg three times a week for 6 months. Creatinine, blood urea nitrogen (BUN) and protein were measured in serum and/or urine by routine laboratory techniques. BUN, creatinine, and proteinuria were significantly lower and creatinine clearance was significantly higher in SO and SO+AC groups when compared with RMR and RMR+AC groups. There were no differ- ences in creatinine, proteinuria and creatinine clearance between RMR and RMR+AC groups. Anyway, RMR+AC group showed significant lower BUN and lower creatinine and proteinuria, and higher creatinine clearance than RMR group. In a model of renal failure induced by RMR, 6 months of treatment with CA may have some beneficial effect on renal function

    Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent mytilid fatty acids by <sup>13</sup>C-fingerprinting

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    Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part oftheir energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assesstheir ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S), CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively). 14:0; 15:0; 16:0; 16:1(n - 7)c+t; 18:1(n - 13)c+t and (n - 7)c+t; 20:1(n - 7); 20:2(n - 9,15); 18:3(n - 7) and (n - 5,10,13) PLFA were labeled in the presence of H13CO3- (+H2S) and 13CH4, while the 12:0 compound became labeled only in the presence ofH13CO3- (+H2S). In contrast, the 17:0; 18:0; 16:1(n - 9); 16:1(n - 8) and (n - 6); 18:1(n - 8); and 18:2(n - 7) PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n - 7,15). Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts

    Effect of pH of H2O2 solutions on the morphology and wear resistance of human dental enamel: an AFM study

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    Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio
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