307 research outputs found

    Estudo do endividamento da administração local: evidência empírica usando modelos de dados em painel

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    O objetivo desta investigação é o de identificar, tendo como base o período de 2004 a 2009, os fatores determinantes do endividamento dos municípios portugueses, tentando perceber quais o influenciame de que forma. Serão estudados fatores institucionais, políticos, fiscais e económico-financeiros. Utilizar-se-á a metodologia de tratamento de dados em painel aplicada aos municípios da região de Lisboa. Esta metodologia mostra-se adequadaao tipo de estudo que se pretende elaborar, pois permite analisar simultaneamente as variações intermunicípios (dimensão seccional) e ao longo do tempo (dimensão temporal). Os resultados indicam-nos que os fatores determinantes do grau de endividamento, dos municípios da região de Lisboa, são a dimensão, a capacidade turística, a forma de governação e as receitas fiscais

    Factores determinantes do endividamento na administração local portuguesa: evidência empírica nos municípios do Alto Trás-os-Montes

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    O objectivo desta investigação é a definição de um modelo que identifique e conjugue os determinantes do nível de endividamento na Administração Local portuguesa, tomando como referência o caso específico dos municípios do Alto Trás-os-Montes para os anos de 2006 e 2007. A validação do modelo de regressão linear múltipla permitiu concluir que as variáveis institucionais, político-ideológicas, fiscais e económico-financeiras parecem influenciar o endividamento dos municípios da região do Alto Trás-os-Montes. São, no entanto, as económico-financeiras que melhor o explicam, dado ter-se obtido para todas elas, no conjunto dos dois anos estudados, evidência estatística significativa. Constatou-se também que existem diferenças nos determinantes do endividamento para os anos de 2006 e 2007

    Conjugated linoleic acid production and probiotic assessment of Lactobacillus plantarum isolated from Pico cheese

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    peer-reviewedLactic acid bacteria isolated from a traditional Azorean cheese were screened for their ability to convert free linoleic acid to conjugated linoleic acid (CLA). Two strains of Lactobacillus plantarum were recognized as potential CLA producers. GC analysis identified cis-9, trans-11 C18:2 as the predominant isomer (10–14 μg/mL), followed by trans-9, trans-11 C18:2 (4–6 μg/mL). The CLA producing strains demonstrated strong biofilm capacity, high cell surface hydrophobicity and good auto-aggregation ability. These strains were capable of surviving in the presence of bile salts (0.3%) and pancreatin (0.1%), but only the highest CLA producer (L3C1E8) was able to resist low pH (2.5). Moreover, the CLA-producers showed good adhesion capacity to intestinal human cells (Caco-2 and HT-29) and were able to prevent colonization of Escherichia coli. Of the two strains, Lactobacillus plantarum L3C1E8 revealed superior probiotic properties and great potential for producing food products enriched in the two CLA isomers, cis-9, trans-11 C18:2 (60%) and trans-9, trans-11 C18:2 (25%)

    The Influence of Customer Retention Time on Slogan Recall and Recognition: An Empirical Study

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    This research intends to explore some of the roots that might influence the effectiveness of slogans. The specific aim of the study is to examine the relationship between the customer retention time and the recall and recognition of brand slogans. This is as an important issue to be studied on branding, because no previous studies were found, and the better understanding of such relationship will help on deciding which marketing mix elements should be managed in order for the brands to obtain a more memorable and stable position in the consumers’ mind. An empirical quantitative study was conducted with an online survey research method employed to collect data from 370-real consumers of three B2C brands in telecom industry. The results revealed that customer seniority (retention time) did not significantly influence slogan recall nor recognition.info:eu-repo/semantics/publishedVersio

    Graphene oxide layer-by-layer films for sensors and devices

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    Funding Information: Funding: The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007–2013) CALIPSO under grant agreement number 312284 and from the Portuguese funding agency FCT—Fundação para a Ciência e a Tecnologia—within projects UID/EEA/50014/2019, UID/FIS/00068/2019, PTDC/FIS-NAN/0909/2014, UID/FIS/00068/2019, the Bilateral Project entitled “Deteção de Estrogénio-um Contaminante Emergente em Corpos Hídricos” within the scope of “Cooperação Transnacional_FCT (Portugal)-CAPES (Brazil) 2018”.Layer-by-layer films of poly (allylamine hydrochloride) (PAH) and graphene oxide (GO) were characterized, looking at growth with the number of bilayers, morphology, and electrical properties. The PAH/GO films revealed a linear increase in absorbance with the increase in the number of deposited bilayers, allowing the determination that 10.7 ± 0.1 mg m−2 of GO is adsorbed per unit of area of each bilayer. GO absorption bands at 146, 210, 247 and 299 nm, assigned to π-π* and n-π* transitions in the aromatic ring (phenol) and of the carboxylic group, respectively, were characterized by vacuum ultraviolet spectroscopy. The morphological characterization of these films demonstrated that they are not completely uniform, with a bilayer thickness of 10.5 ± 0.7 nm. This study also revealed that the films are composed of GO and/or PAH/GO fibers and that GO is completely adsorbed on top of PAH. The electrical properties of the films reveal that PAH/GO films present a semiconductor behavior. In addition, a slight decrease in conduction was observed when films were prepared in the presence of visible light, likely due to the presence of oxygen and moisture that contributes to the damage of GO molecules.publishersversionpublishe

    Ethanol production from enzymatically pretreated wheat straw

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    Lignocellulosic biomass can be utilized to produce ethanol, a promising alternative energy source for the limited crude oil. Wheat straw is an abundant agricultural residue which can be used as lignocellulosic raw material for bioconversion. There are mainly two processes involved in the bioconversion: hydrolysis of cellulose in the lignocellulosic biomass to produce reducing sugars, and fermentation of the sugars to ethanol. The current study involved the optimization of enzymatic hydrolysis of a wheat straw pretreated by acid hydrolysis, using a mixture of commercial cellulases: celluclast 1.5L + Novozym 188, with further fermentation of the hydrolisate’ sugar content by three ethanologenic strains, namely two yeast of Saccharomyces cerevisiae (strains F and K) and a bacterial strain, Zymomonas mobilis (strain CP4). The fermentation assays, using undiluted hydrolisate with or without nutrient supplements, were monitored by the evaluation of glucose and ethanol yields. In the assays using no supplemented hydrolisate the results obtained for the two yeasts strains F and K, and Zymomonas mobilis were 74%, 79% and 58% of ethanol yield, respectively. However, when the hydrolisate was supplemented the fermentation results showed a better bioconversion process by the Z. mobilis, reaching 98% ethanol yield while the two strains of S. cerevisiae used maintained their behaviour. So, the fermentation results showed the necessity of the addition of nutrients for a good bioconversion process by the Z. mobilis, resulting in better ethanol yield than S. cerevisiae strains (F and K) from WSP hydrolisate

    Assessing the Potential of Sensors Based on LbL and Sputtering Films

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    Funding text This research was funded by the project PCIF/GFC/0078/2018: influence of forest VOCs (volatile organic compounds) on extreme fire behavior at Fundação para a Ciência e a Tecnologia (FCT). The authors also thankful for the research center grants no. UIDB/FIS/04559/2020 and no. UIDP/FIS/04559/2020 (LIBPhys) from FCT/MCTES, Portugal.A new theory suggests that flammable gases generated by heated vegetation, in particular the volatile organic compounds (VOC) common to Mediterranean plants, may, under certain topographic and wind conditions, accumulate in locations where, after the arrival of the ignition source, they rapidly burst into flames as explosions. Hence, there is a need for the development of a system that can monitor the development of these compounds. In this work, a sensor's array is proposed as a method for monitoring the amount of eucalyptol and α-pinene, the major VOC compounds of the Eucalyptus and Pine trees. The detection of the target compounds was assessed using the impedance spectroscopy response of thin films. Combinations of layers of polyelectrolytes, such as poly(allylamine hydrochloride) (PAH), polyethyleneimine (PEI), poly(sodium 4-sytrenesulfonate) (PSS) graphene oxide (GO), and non/functionalized multiwall nanotubes (MWCNT-COOH or MWCNT), namely, PAH/GO, PEI/PSS, PEI/GO, PAH/MWCNT, PAH/MWCNT-COOH, films, and TiO2 and ZnO sputtered films, were deposited onto ceramic supports coated with gold interdigitated electrodes. The results showed that concentrations of the target VOCs, within the range of 68 to 999 ppmv, can be easily distinguished by analyzing the impedance spectra, particularly in the case of the ZnO- and PAH/GO-film-based sensors, which showed the best results in the detection of the target compounds. Through principal component analysis (PCA), the best set of features attained for the ZnO and PAH/GO based sensor devices revealed a linear trend of the PCA's first principal component with the concentration within the range 109 and 807 ppmv. Thus, the values of sensitivity to eucalyptol and α-pinene concentrations, which were (2.2 ± 0.3) × 10-4 and (5.0 ± 0.7) × 10-5 per decade, respectively, as well as resolutions of 118 and 136 ppbv, respectively, were identified.publishersversionpublishe

    Kinetics of a packed-bed bacth reactor for the treatment of olive oil wastewaters from a Portuguese mill

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    Olive oil production is a traditional agricultural industry in Mediterranean countries and Portugal is one of the ten major producers. This industry generates an effluent, olive mill wastewater. This effluent does not undergo any treatment and is usually stored in evaporation lagoons or spread on the land. This can have a negative impact in the environment since this effluent has a high level of organic matter leading to a high chemical oxygen demand. In addition it has also a high content of polyphenols that contributes to the ecotoxicity of this effluent.Different techniques for the treatment of these wastewaters have been studied. In this work a 60 litre vessel was filled with a packaging of plastic material consisting of a cubic geometry (Biological Carrier Media from Rauschert). The non-inoculated reactor was filled with effluent from an olive mill farm (from Alfândega da Fé, Trás-os-Montes) and the effluent was re-circulated daily for homogeneity. COD, colour, nitrogen, solids and phosphorous were measured to follow the evolution of the system. Microbial composition and polyphenols were also evaluated. As an indicator of the microbial activity in the reactor, lipase activities were measured. Ecotoxicity tests were carried out to follow the detoxification capacity of the system as well as its potential for using in the treatment of this type of agroindustrial effluent

    Olive Mill wastewater bioremediation towards detoxification

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    Olive oil production is a traditional agricultural industry in Mediterranean countries and Portugal is one of the ten major producers. This industry generates an effluent, olive mill wastewater (OMW), which does not undergo any treatment and, usually, is stored in evaporation lagoons or spread on the land. Disposal of olive oil mill wastewaters is a serious environmental problem due to its high organic loading, presence of polyphenols and tannins, high content in suspended solids and acidity, which contributes to its ecotoxicity. In this work it was intended to study the biodegradation of OMW by microrganisms naturally present in these wastewaters. Thus, an aerobic biological treatment system: a packed-bed batch reactor was applied to a OMW from a mill on northern of Portugal, exploring its autochthon microbial population as inoculum. The biodegradation ability of OMW by microrganisms naturally present in these wastewaters was assessed, by following the evolution of the process and monitoring several of its physico-chemical parameters. Furthermore, an ecotoxicological evaluation, using chronic toxicity tests (Pseudomonas putida growth inhibition test and Vibrio fischeri growth inhibition test), was performed to follow the detoxification capacity of the system as well as its potential to be used in the treatment of this type of agroindustrial effluent

    Molecular characterization of PDGFR-α/PDGF-A and c-KIT/SCF in gliosarcomas

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    Gliosarcomas are rare and poorly characterized malignant brain tumors that exhibit a biphasic tissue pattern with areas of gliomatous and sarcomatous differentiation. These tumors are histological variants of glioblastoma, displaying a similar genetic profile and dismal prognosis. Up-regulation of PDGFR subfamily of tyrosine kinase members, PDGFR-α and c-Kit, and their intracellular effectors RAS/RAF/MAPK has a crucial role in the cancer development. In addition, signal transduction mediated by activating mutations of c-Kit and PDGFR can be effectively blocked by specific tyrosine kinase inhibitors, such as Imatinib mesylate. The aim of this study was to characterize the molecular alterations of PDGFR signaling in gliosarcomas. Six cases were analyzed by immunohistochemistry for the expression of PDGFR-α, c-Kit and their ligands PDGF-A and SCF, respectively. The cases were further evaluated for the presence of activating mutations of PDGFR-α (exons 12 and 18) and c-kit (exons 9, 11, 13, and 17), as well as B-RAF (exons 11 and 15). Expression of PDGF-A was found in all cases and co-expression of PDGFR-α was observed in three cases. Four cases showed expression of SCF, and c-Kit was observed only in one case that also expressed SCF. Generally, immunoreaction predominates in the glial component. The mutational analysis of PDGFR-α showed the presence of an IVS17-50insT intronic insertion in two cases, one of them also with a 2472C > T silent mutation; this silent mutation was also found in another case. Glioma cell line analysis of IVS17-50insT insertion showed no influence on PDGFR-α gene splicing. No mutations were detected in c-kit and B-RAF oncogenes. Our results indicate that activating mutations of PDGFR-α, c-kit and B-RAF are absent in gliosarcomas. Nevertheless, the presence of a PDGFR-a/PDGFA and c-Kit/SCF autocrine/paracrine stimulation loop in a proportion of cases, supports the potential role of specific tyrosine kinase inhibitors in the treatment of gliosarcomas.Novartis Portugal
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