1,311 research outputs found
Tourism sector competitiveness in Portugal: applying Porter's Diamond
The tourism sector has stood out for its enormous capacity for growth on a global scale and holding a relevant role both as a tool for the competitiveness and as a driver of regional development. This profile stems not only from its multiplier effects but also the opportunities susceptible to identification within the scope of offsetting regional disparities in growth and prosperity. The objective of this research project consists of evaluating the competitiveness of the regional areas and directorates of tourism in Portugal with the methodology applied requiring the input of primary data (a sample of 446 companies), through a questionnaire aimed at companies displaying the activities characteristic of the World Tourism Organisation satellite account. Through the application of Porter’s Diamond Model, we arrived at a conceptual model through recourse to the Partial Least Square – Path Modelling technique with the objective of analysing the relationships unfolding among the determinant variables to competitiveness in the tourism sector. Despite the results returned proving clear, we also verify that encapsulating competitiveness proves no easy task given how Portugal reports regions with simultaneously very varied and very specific characteristics.O sector do turismo destaca-se pela enorme capacidade de crescimento a nível mundial, desempenhando um papel relevante tanto como ferramenta para a competitividade como enquanto motor do desenvolvimento regional. Este perfil decorre não apenas dos seus efeitos multiplicadores, mas também das oportunidades suscetíveis de identificação no âmbito da compensação das disparidades regionais no crescimento e prosperidade. O objetivo desta investigação consiste em avaliar a competitividade das áreas regionais e direções do turismo em Portugal. Utilizamos dados primários (uma amostra de 446 empresas), através de um questionário destinado a empresas que exibem as atividades características da conta satélite da Organização Mundial de Turismo. Através da aplicação do Modelo de Diamante de Porter, alcançamos um modelo conceitual através do recurso à técnica de Partial Least Square – Path Modelling com o objetivo de analisar as relações que se desdobram entre as variáveis determinantes para a competitividade no setor de turismo. Apesar de os resultados retornados serem claros, verificamos também que o encapsulamento da competitividade não se revela uma tarefa fácil, dado o fato de Portugal englobar regiões com características simultaneamente muito variadas e muito específicas
The role of entrepreneurial ecosystems in the SME internationalization
The Entrepreneurial Ecosystems (EE) articulate concepts from various streams of literature and are formed by multiple stakeholders and relate to different levels of analysis. Although the literature shows a growing relevance on the theme of EE, most studies reveal to be conceptual, and the existence of empirical studies with quantitative methodologies is still scarce. This study attempts to contribute to filling this gap by developing a dynamic model of EE and its impact on the small and medium-sized enterprises (SME) international performance by aggregating different levels of analysis. Based on a sample of 120 SMEs, the results suggest that macro (agents) and meso (different partners) level variables positively impact international performance. We also find that technology transfer has a negative moderating effect on the meso level relationship of EE with digital performance. Our study also contributes to a greater understanding of the Entrepreneurial Ecosystems, its internationalization and the digital performance effect.info:eu-repo/semantics/publishedVersio
Antimicrobial activity of quinoxaline 1,4-dioxide and three derivatives
O presente trabalho descreve o estudo da actividad
e antimicrobiana de quarto derivados da quinoxalina N,N-dióxido: quinoxalina 1,4-dióxido, 2-metilquinoxalina 1,4-
dióxido, 6-cloro-2,3-dimetilquinoxalina 1,4-dióxido e 3-benzoil-2-metilquinoxalina 1,4-
dióxido contra as estirpes bacterianas Geobacillus stearothermophilus ATCC 10149,
Escherichia coli ATCC 25922, Escherichia coli HB101, Escherichia coli (blaTEM,
blaCTX-M) e Salmonella (blaCTX-M), assim como contra a estirpe de levedura
Saccharomyces cerevisiae PYCC 4072. A determinação da concentração mínima
inibitória (MIC) foi realizada pelo método de diluição. Os valores de MIC’s foram
estimados para cada composto e estirpe. Os resultados obtidos sugerem potenciais
novas drogas para quimioterapia.The present work reports the study of the antimicrobial activity of four
quinoxaline N,N-dioxide: quinoxaline 1,4-dioxide, 2-methylquinoxaline 1,4-dioxide, 6-
chloro-2,3-dimethylquinoxaline 1,4-dioxide and 3-benzoyl-2-methylquinoxaline 1,4-
dioxide against Geobacillus stearothermophilus ATCC 10149, Escherichia coli ATCC
25922, Escherichia coli HB101, Escherichia coli (blaTEM, blaCTX-M) and
Salmonella (blaCTX-M) bacterial strains and also against the yeast Saccharomyces
cerevisiae PYCC 4072. The determination of the minimal inhibitory concentration
(MIC) was performed by the dilution method. The MIC values were estimated for each
compound and each microorganism. The results obtained suggest potential new drugs
for antimicrobial chemotherapy
Prevailing theoretical approaches predicting sustainable business models: a systematic review
Purpose: This study aims to map scientific publications, intellectual structure and research trends in the sustainable business model (SBM) field. Specifically, it attempts to (1) identify the fundamental contributions of research in this area of knowledge; and (2) determine the research lines that constitute the most prominent intellectual structure. We leverage these insights to formulate and propose a future research agenda for SBM. Design/methodology/approach: The authors made recourse to the bibliometric, co-citation and cluster analysis techniques. To evaluate potential patterns among articles, we analysed how articles are jointly cited. We further applied hierarchical cluster analysis to the articles and used co-citation analysis to group the interrelated articles into distinct sets. Findings: The results enable the identification and classification of the prevailing theoretical foci in the domain of SBM: (1) SBM implementation; (2) SBM challenges; (3) institutional SBM; (4) circular SBM; and (5) emerging SBM. Originality/value: This study identifies, explores, analyses and summarises the main theoretical approaches and themes surrounding SBM research to date, contributing to deepening the literature by identifying the priority areas concerning sustainable business models and encouraging future research of an internationally excellent standard.info:eu-repo/semantics/acceptedVersio
Antimicrobial activity of pyrazine and quinoxaline N,N’-dioxide heterocyclic compounds
The nitrogen heterocyclic organic compounds 1,4 dioxide pyrazine and quinoxaline derivatives have been widely studied due to their potential use as synthetic drugs. The thermochemical study of three N,N´-dioxides: 2,3,5-trimethylpyrazine-1,4-dioxide, tetramethylpyrazine-1,4-dioxide and 6-chloro-2,3-dimethilquinoxaline 1,4-dioxide has been recently developed in order to establish relationships among the energetical, structural and reactivity properties [4,5]. Several studies have reported their pharmacological activity, particularly as antimicrobial agents [1,2,3]. It has also been established a relation between energetical and structural properties and biological activity, once these compounds present N – oxide bonds, increasing their oxidative capacity.
The present work reports the study of antimicrobial activity for those compounds against the bacteria Geobacillus stearothermophylus, Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli and also against the yeasts Saccharomyces cerevisiae PYCC 4072, Candida albicans PYCC3436T, Candida tropicalis PYCC, Issatchenka Orientalis PYCC. The determination of the minimal inhibitory concentration (MIC), points to an antimicrobial activity and the preliminary results indicate that these compounds may be potential candidates as antimicrobial drugs with clinical, agriculture or food industries applications
Antibiotic resistance in wastewater: Occurrence and fate ofEnterobacteriaceaeproducers of Class A and Class C β-lactamases
Antibiotics have been intensively used over the last decades in human and animal therapy and livestock, resulting in serious environmental and public health problems, namely due to the antibiotic residues concentration in wastewaters and to the development of antibiotic-resistant bacteria. This study aimed to access the contribution of some anthropological activities, namely urban household, hospital and a wastewater treatment plant, to the spread of antibiotic resistances in the treated wastewater released into the Mondego River, Coimbra, Portugal. Six sampling sites were selected in the wastewater network and in the river. The ampicillin-resistant Enterobacteriaceae of the water samples were enumerated, isolated and phenotypically characterized in relation to their resistance profile to 13 antibiotics. Some isolates were identified into species level and investigated for the presence of class A and class C -lactamases. Results revealed high frequency of resistance to the -lactam group, cefoxitin (53.5%), amoxicillin/clavulanic acid combination (43.5%), cefotaxime (22.7%), aztreonam (21.3) cefpirome (19.2%), ceftazidime (16.2%) and to the non--lactam group, trimethoprim/sulfamethoxazol (21.1%), tetracycline (18.2%), followed by ciprofloxacin (14.1%). The hospital effluent showed the higher rates of resistance to all antibiotic, except two (chloramphenicol and gentamicin). Similarly, higher resistance rates were detected in the wastewater treatment plant (WWTP) effluent compared with the untreated affluent. Regarding the multidrug resistance, the highest incidence was recorded in the hospital sewage and the lowest in the urban waste. The majority of the isolates altogether are potentially extended-spectrum -lactamases positive (ESBL(+)) (51.9%), followed by AmpC(+) (44.4%) and ESBL(+)/AmpC(+) (35.2%). The most prevalent genes among the potential ESBL producers were blaOXA (33.3%), blaTEM (24.1%) and blaCTX-M (5.6%) and among the AmpC producers were blaEBC (38.9%), blaFOX (1.9%) and blaCIT (1.9%). In conclusion, the hospital and the WWTP activities revealed to have the highest contribution to the spread of multidrug resistant bacteria in the study area. Such data is important for future management of the environmental and public health risk of these contaminants. This is the first embracing study in the water network of Coimbra region on the dissemination of antibiotic resistance determinants. Moreover, it is also the first report with the simultaneous detection of multiresistant bacteria producers of AmpC and ESBLs -lactamases in aquatic systems in Portugal.info:eu-repo/semantics/publishedVersio
Additive manufacturing of embedded thermocouples in WC-Co cutting tools for cutting temperature measurement
A publicar em PowderMet2023, 18 - 21 jun. 2023, Caesars Palace, Las Vegas, USADuring machining processes, a large amount of heat is generated due to deformation of the material and friction of the chip along the surface of the tool, especially in the cutting zone. This high temperature strongly influences tribological phenomena and adhesion, tool wear, tool life, workpiece surface integrity and quality, chip formation mechanisms and contribute to the thermal deformation of the cutting tool, leading to high operating costs and reduction of the end product quality. In this sense, being able to assess the cutting temperature in real time, at various points of the cutting tool during machining processes, is of utmost importance to effectively optimize cutting parameters and the cutting fluid flow adequately, for minimizing heat generation, temperature and consequently wear, allowing to increase tool life.
This work proposes the fabrication of embedded additively manufactured type K and type N thermocouples by laser powder bed fusion for real time cutting temperature measurement. Processing parameters optimization was performed to obtain a dense and continuous thermocouple with no significant defects and the additively manufactured thermocouples were tested in comparison to a conventional thermocouple. The obtained results show that this approach is effective to produce embedded thermocouples in WC-Co cutting tools capable of measuring cutting temperature, which will allow a real time optimization of the cutting parameters, namely cutting speed, feed and depth of cut, during in-service time, thus enhancing tool performance and life.This work was supported by FCT (Fundação para a Ciência e a Tecnologia) through the grant
2020.07155.BD and by the project POCI-01-0145-FEDER-030353 (SMARTCUT) and PTDC/EMEEME/1442/2020 (Add2MechBio). Additionally, this work was supported by FCT national funds, under the national support to R&D units grant, through the reference projects UIDB/04436/2020 and
UIDP/04436/2020. Finally, this work was also developed within the scope of the project CICECO-Aveiro
Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national
funds through the FCT/MCTES (PIDDAC)
Antigenotoxic effects of quercetin, rutin and ursolic acid on HepG2 cells : evaluation by the comet assay
In the present study, the chemoprotective effects of quercetin, rutin and ursolic acid on tert-butyl hydroperoxide (t-BHP)-induced DNA damage in a human hepatoma cell line (HepG2) were investigated by the comet assay. To determine whether protection was due to direct chemical interactions alone or to cellular-mediated responses three different types of treatments were used: simultaneous incubation of cells with individual test compounds and the toxicant; pre-treatment with test compound before addition of the toxicant followed or not by a recovery period. The expression of Hsp70 was quantified by Western blotting to test the involvement of heat shock proteins in the cellular responses to the test compounds. In addition, effects on proliferation were evaluated by the MTT assay. The results show that quercetin and ursolic acid prevented DNA damage and had antiproliferative properties in HepG2 cells suggesting an anticarcinogenic potential for these compounds. The protective effects of quercetin against t-BHP-induced DNA damage seem to be due to both direct effects on t-BHP toxicity and to cellularly mediated indirect effects which reflect the potentiation of the cellular antioxidant defenses. Ursolic acid seems to exert effects only through cellularly mediated mechanisms since it was not protective in simultaneous incubation. Quercetin and ursolic acid also showed to increase the rate of DNA repair. Rutin did not have effects at any level. These results, obtained with liver cells, emphasize and confirm the chemopreventive potential of quercetin and ursolic acid, which may help explain the lower cancer incidence in human population with high dietary intakes of fruits and vegetables. These results also demonstrate that Hsp70 is not involved in the observed effects in HepG2.Fundação para a Ciência e a Tecnologia (FCT) - UMINHO/POCI-62040/BI/1/06, SFRH/BPD/26316/2006, POCI/AGR/62040/2004
The drinking of a Salvia officinalis infusion improves liver antioxidant status in mice and rats
In this study we evaluate the biosafety and bioactivity (antioxidant potential) of a traditional water infusion (tea) of common sage (Salvia officinalis L.) in vivo in mice and rats by quantification of plasma transaminase activities and liver GST and GR enzyme activities. The replacement of water by sage tea for 14 days in the diet of rodents did not affect the body weight and food consumption and did not induce liver toxicity. On the other hand, a significant increase of liver GST activity was observed in rats (24%) and mice (10%) of sage drinking groups. The antioxidant potential of sage tea drinking was also studied in vitro in a model using rat hepatocytes in primary culture. The replacement of drinking water with sage tea in the rats used as hepatocyte donors resulted in an improvement of the antioxidant status of rat hepatocytes in primary culture, namely a significant increase in GSH content and GST activity after 4 hours of culture. When these hepatocyte cultures were exposed to 0.75 or 1 mM of tert-butyl hydroperoxide for 1 hour, some protection against lipid peroxidation and GSH depletion was conferred by sage tea drinking. However, the cell death induced by t-BHP as shown by LDH leakage was not different from that observed in cultures from control animals. This study indicates that the compounds present in this sage preparation contain interesting bioactivities which improve the liver antioxidant potential.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/6942/2001, Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI) - POCTI/AGR/43482/2001
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