48 research outputs found

    As PPP em Portugal - Uma estimativa do número de passageiros para o Metro Sul do Tejo

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    Trabalho de projeto de mestrado, Matemática Aplicada à Economia e Gestão, Universidade de Lisboa, Faculdade de Ciências, 2019Ao longo das últimas décadas, tem se verificado em grande parte dos países, a tendência para os governos entregarem ao setor privado, ramos de atividade que até então eram geridos pelo setor público. Tal situação é motivada pela escassez de recursos financeiros por parte do Estado, bem como pela necessidade de aumentar a oferta, a qualidade e a eficiência dos serviços públicos. Deste modo, existiu um crescimento notável e exponencial da utilização das Parcerias Público-Privadas (PPPs), sendo que Portugal aparece destacado na utilização deste tipo de contratos em relação a outros países europeus, dada a situação financeira extremamente delicada que atravessou durante vários anos, associada a uma conjuntura económica global pouco favorável ao cumprimento das metas orçamentais. Contudo, este notável crescimento levou a que muitos projetos não tivessem um modelo sólido e os seus riscos devidamente acautelados, de forma a ser possível corrigir falhas ou imperfeições, conforme sucedeu com o Metro Sul do Tejo (MST). O presente trabalho tem como objetivo basilar fazer uma contextualização das Parcerias Público-Privadas a nível europeu e, em particular, em Portugal. Além disso, pretende fazer um estudo da forma como o projeto do MST foi estruturado e compreender as questões-chave que levam a encargos de milhões de euros anuais para o Estado, através da análise das suas condições contratuais, das renegociações e das discrepâncias entre a procura prevista no cenário do Caso Base e a procura efetiva que na realidade se veio a verificar. Através do cálculo de uma estimativa do número de potenciais passageiros do MST, e de acordo com os dados dos Censos do ano de 2001, será possível tirar como conclusão basilar que o valor do limite mínimo da banda de tráfego de referência garantida contratualmente era demasiado otimista, tendo em conta o número de indivíduos que à época realizava movimentos pendulares no concelho de Almada.Over the last few decades, it has been verifying in many countries towards governments delivering to the private sector, some industries that until then had been managing by the public sector. This situation was prompted by the lack of financial resources by the country Governments, as well as by the need to increase the supply, quality and efficiency of public services. As a result, it was an exponential increase of Public Private Partnerships arrangements and Portugal is highlighted in these kinds of contracts use, in relation to other European countries. This issue was caused not only due to the really painful financial situation that it had been experiencing for several years, but also the economic issues around the World that were not conducive to be compliance with the budgetary targets. However, this remarkable growth has led to many projects did not have a solid model and their risks properly prevented, in order to be able to correct some shortcomings and imperfections, as it has been happening with the Metro Sul do Tejo (MST). The main purpose of this study is to contextualize the Public Private Partnerships in Europe and, particularly, in Portugal. Furthermore, it intends to make a study the structure of MST and then understand the key issues that leads to millions of euros of obligations for the Government, through the analysis of its contractual conditions, the renegotiations and the discrepancies between the demand foreseen in the Base Case scenario and the real demand. By calculating an estimation of the number of potential passengers of the MST, and according to the 2001 Census data, it will be possible to draw as main conclusion that the value of the minimum reference band, contractually guaranteed, was too optimistic, taking into account the number of people who, at that time, performed commuting movements at Almada area

    Localized redox relays as a privileged mode of cytoplasmic hydrogen peroxide signaling

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    Hydrogen peroxide (H2O2) is a key signaling agent. Its best characterized signaling actions in mammalian cells involve the early oxidation of thiols in cytoplasmic phosphatases, kinases and transcription factors. However, these redox targets are orders of magnitude less H2O2-reactive and abundant than cytoplasmic peroxiredoxins. How can they be oxidized in a signaling time frame? Here we investigate this question using computational reaction-diffusion models of H2O2 signaling. The results show that at H2O2 supply rates commensurate with mitogenic signaling a H2O2 concentration gradient with a length scale of a few tenths of μm is established. Even near the supply sites H2O2 concentrations are far too low to oxidize typical targets in an early mitogenic signaling time frame. Furthermore, any inhibition of the peroxiredoxin or increase in H2O2 supply able to drastically increase the local H2O2 concentration would collapse the concentration gradient and/or cause an extensive oxidation of the peroxiredoxins I and II, inconsistent with experimental observations. In turn, the local concentrations of peroxiredoxin sulfenate and disulfide forms exceed those of H2O2 by several orders of magnitude. Redox targets reacting with these forms at rate constants much lower than that for, say, thioredoxin could be oxidized within seconds. Moreover, the spatial distribution of the concentrations of these peroxiredoxin forms allows them to reach targets within 1 μm from the H2O2 sites while maintaining signaling localized. The recruitment of peroxiredoxins to specific sites such as caveolae can dramatically increase the local concentrations of the sulfenic and disulfide forms, thus further helping these species to outcompete H2O2 for the oxidation of redox targets. Altogether, these results suggest that H2O2 signaling is mediated by localized redox relays whereby peroxiredoxins are oxidized to sulfenate and disulfide forms at H2O2 supply sites and these forms in turn oxidize the redox targets near these sites.This work was funded by FEDER funds through the Operational Programme Competitiveness Factors - COMPETE and by national funds by FCT - Foundation for Science and Technology under the strategic projects UID/NEU/04539/2013 (AS) and UID/FIS/04564/ 2016 (RT,FSA), and under the grant FCOMP-01-0124-FEDER-020978 (Project PTDC/QUI-BIQ/119657/2010) (AS). RT also acknowledges FCT's support through the FCT Researcher Program

    Enhancing artemisinin solubility in aqueous solutions: searching for hydrotropes based on ionic liquids

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    Artemisinin is a sesquiterpenoid lactone peroxide, known for its potent antimalarial activity that can be extracted from Artemisia annua L. This compound is only sparingly soluble in water, making its extraction using environmental-friendly and non-toxic aqueous solvents difficult. In the attempt to overcome this limitation, hydrotropes, which are a class of compounds that can assist in increasing the solubility of hydrophobic solutes in water, were investigated in this work. In particular, the hydrotropic capability of ionic liquids (ILs) on the aqueous solubility of artemisinin was studied. The effects of IL concentration and anion nature of 1-butyl-3-methylimidazolium-based ILs on the solubility of artemisinin at 303.2 K in water were evaluated. It is here shown the excellent capacity of ILs containing thiocyanate or dicyanamide anions to enhance the solubility of artemisinin in aqueous media, with a magnitude comparable to that obtained with the best organic solvents. Furthermore, solvatochromic parameters of the ILs aqueous solutions were also measured and combined with COSMO-RS and the cooperative hydrotropy model to establish relations between the artemisinin solubility enhancement and the solvent characteristics. The solubility enhancement of artemisinin is favored by the apolarity of the medium and the lower hydrogen-bond acceptor character of the hydrotrope.This work was developed within the scope of the projects CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, CIMO-Mountain Research Center, UIDB/00690/2020, all financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. Isabela Sales and Silvana Mattedi thanks the finantial support from CAPES and CNPq/Brazil (CAPES: Proc. 88881.189075/2018-01 and 88887.494428/2020-00. CNPq: Grant 303089/2019-9 and Proc.438036/2018-2).info:eu-repo/semantics/publishedVersio

    Heterologous expression of Streptococcus mutans cnm in Lactococcus lactis promotes intracellular invasion, adhesion to human cardiac tissues and virulence

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOIn S. mutans, the expression of the surface glycoprotein Cnm mediates binding to extracellular matrix proteins, endothelial cell invasion and virulence in the Galleria mellonella invertebrate model. To further characterize Cnm as a virulence factor, the cnm gene from S. mutans strain OMZ175 was expressed in the non-pathogenic Lactococcus lactis NZ9800 using a nisin-inducible system. Despite the absence of the machinery necessary for Cnm glycosylation, Western blot and immunofluorescence microscopy analyses demonstrated that Cnm was effectively expressed and translocated to the cell wall of L. lactis. Similar to S. mutans, expression of Cnm in L. lactis enabled robust binding to collagen and laminin, invasion of human coronary artery endothelial cells and increased virulence in G. mellonella. Using an ex vivo human heart tissue colonization model, we showed that Cnm-positive strains of either S. mutans or L. lactis outcompete their Cnm-negative counterparts for tissue colonization. Finally, Cnm expression facilitated L. lactis adhesion and colonization in a rabbit model of infective endocarditis. Collectively, our results provide unequivocal evidence that binding to extracellular matrices mediated by Cnm is an important virulence attribute of S. mutans and confirm the usefulness of the L. lactis heterologous system for further characterization of bacterial virulence factors.In S. mutans, the expression of the surface glycoprotein Cnm mediates binding to extracellular matrix proteins, endothelial cell invasion and virulence in the Galleria mellonella invertebrate model. To further characterize Cnm as a virulence factor, the cnm gene from S. mutans strain OMZ175 was expressed in the non-pathogenic Lactococcus lactis NZ9800 using a nisin-inducible system. Despite the absence of the machinery necessary for Cnm glycosylation, Western blot and immunofluorescence microscopy analyses demonstrated that Cnm was effectively expressed and translocated to the cell wall of L. lactis. Similar to S. mutans, expression of Cnm in L. lactis enabled robust binding to collagen and laminin, invasion of human coronary artery endothelial cells and increased virulence in G. mellonella. Using an ex vivo human heart tissue colonization model, we showed that Cnm-positive strains of either S. mutans or L. lactis outcompete their Cnm-negative counterparts for tissue colonization. Finally, Cnm expression facilitated L. lactis adhesion and colonization in a rabbit model of infective endocarditis. Collectively, our results provide unequivocal evidence that binding to extracellular matrices mediated by Cnm is an important virulence attribute of S. mutans and confirm the usefulness of the L. lactis heterologous system for further characterization of bacterial virulence factors811829FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2014/07231-0; 2013/25080-7308644/2011-

    Communication Skills in Foreign Languages in Engineering

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    This article is devoted to innovative methods of teaching ESL. The factors of development of engineering activities are shown and the prerequisites for the component composition of a foreign language professional communicative competence are identified. The first positions in achieving the effectiveness of business communication are the verbal activities of the engineer

    Transcriptional and phenotypic characterization of novel Spx-regulated genes in Streptococcus mutans

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    CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOIn oral biofilms, two of the major environmental challenges encountered by the dental pathogen Streptococcus mutans are acid and oxidative stresses. Previously, we showed that the S. mutans transcriptional regulators SpxA1 and SpxA2 (formerly SpxA and SpxB, respectively) are involved in stress survival by activating the expression of classic oxidative stress genes such as dpr, nox, sodA and tpx. We reasoned that some of the uncharacterized genes under SpxA1/A2 control are potentially involved in oxidative stress management. Therefore, the goal of this study was to use Spx-regulated genes as a tool to identify novel oxidative stress genes in S. mutans. Quantitative real-time PCR was used to evaluate the responses of ten Spx-regulated genes during H2O2 stress in the parent and Delta spx strains. Transcription activation of the H2O2-induced genes (8 out of 10) was strongly dependent on SpxA1 and, to a lesser extent, SpxA2. In vitro transcription assays revealed that one or both Spx proteins directly regulate three of these genes. The gene encoding the FeoB ferrous permease was slightly repressed by H2O2 but constitutively induced in strains lacking SpxA1. Nine genes were selected for downstream mutational analysis but inactivation of smu127, encoding a subunit of the acetoin dehydrogenase was apparently lethal. In vitro and in vivo characterization of the viable mutants indicated that, in addition to the transcriptional activation of reducing and antioxidant pathways, Spx performs an important role in iron homeostasis by regulating the intracellular availability of free iron. In particular, inactivation of the genes encoding the Fe-S biogenesis SUF system and the previously characterized iron-binding protein Dpr resulted in impaired growth under different oxidative stress conditions, increased sensitivity to iron and lower infectivity in rats. These results serve as an entryway into the characterization of novel genes and pathways that allow S. mutans to cope with oxidative stress.In oral biofilms, two of the major environmental challenges encountered by the dental pathogen Streptococcus mutans are acid and oxidative stresses. Previously, we showed that the S. mutans transcriptional regulators SpxA1 and SpxA2 (formerly SpxA and SpxB, respectively) are involved in stress survival by activating the expression of classic oxidative stress genes such as dpr, nox, sodA and tpx. We reasoned that some of the uncharacterized genes under SpxA1/A2 control are potentially involved in oxidative stress management. Therefore, the goal of this study was to use Spx-regulated genes as a tool to identify novel oxidative stress genes in S. mutans. Quantitative real-time PCR was used to evaluate the responses of ten Spx-regulated genes during H2O2 stress in the parent and Delta spx strains. Transcription activation of the H2O2-induced genes (8 out of 10) was strongly dependent on SpxA1 and, to a lesser extent, SpxA2. In vitro transcription assays revealed that one or both Spx proteins directly regulate three of these genes. The gene encoding the FeoB ferrous permease was slightly repressed by H2O2 but constitutively induced in strains lacking SpxA1. Nine genes were selected for downstream mutational analysis but inactivation of smu127, encoding a subunit of the acetoin dehydrogenase was apparently lethal. In vitro and in vivo characterization of the viable mutants indicated that, in addition to the transcriptional activation of reducing and antioxidant pathways, Spx performs an important role in iron homeostasis by regulating the intracellular availability of free iron. In particular, inactivation of the genes encoding the Fe-S biogenesis SUF system and the previously characterized iron-binding protein Dpr resulted in impaired growth under different oxidative stress conditions, increased sensitivity to iron and lower infectivity in rats. These results serve as an entryway into the characterization of novel genes and pathways that allow S. mutans to cope with oxidative stress104CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES [6849-12-1]FAPESP [2012/032278-3, 2014/03816-4]6849-12-12012/032278-3; 2014/03816-

    Social support from the perspective of adolescent victims of domestic violence

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    Objective: Assess the understanding of adolescents regarding the social support received in situations of domestic violence. Method: A qualitative study with data collection carried out through focus groups with 17 adolescent victims of domestic violence, institutionally welcomed in Campinas-SP, and through semi-structured interviews with seven of these adolescents. Information was analyzed by content analysis, thematic modality. Results: Observing the thematic categories it was found that social support for the subjects came from the extended family, the community, the Guardianship Council, the interpersonal relationships established at the user embracement institution and from the religiosity/spirituality. Conclusion: The mentioned sources of support deserve to be enhanced and expanded. With the current complexity of the morbidity and mortality profiles, especially in children and adolescents, the (re)signification and the (re)construction of health actions is imperative
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