1,691 research outputs found

    A deeper look into value investing's future prospects

    Get PDF
    Since value investing’s golden era, many things have changed: from the way individuals invest their savings, to the diversity of financial products available on the market, from the hierarchical and financial structure of the majority of the firms to the way how business is done, from the regulations that rule firms and the market, to the world economy in general, and finally, of course: the very philosophy behind value investing has also progressively changed. Only one thing does not seem to have changed: the performance criteria used to evaluate this investment theory. In recent years, when applied these criteria, the academia noticed value investing releveled relatively poor performance compared to what investors and the market were used to. But can these results be blindly trusted? When everything does seem to have changed, does it make sense to expect valid results applying the same criteria to completely different realities? That is what we propose ourselves to find out. In the present work we will provide an alternative framework to the one used by the academia over the years. We will expose some of the reasons that may motivate this (apparent) underperformance, and alternatives to overcome these difficulties. Our intention is clear: to evaluate if value investing has really lost its hedge, or if on the other hand, academics have just been measuring performance with outdated and unfitted criteria to the current reality.Desde a era de ouro da teoria do investimento em valor, muitas coisas mudaram: desde a forma como os indivíduos investem as suas poupanças, até à diversidade de produtos financeiros disponíveis no mercado, desde a estrutura hierárquica e financeira da maioria das empresas até à forma como se fazem negócios, desde a regulamentação que rege as empresas e o mercado, até à economia mundial em geral e, finalmente, como não poderia deixar de ser: a própria filosofia do investimento em valor também tem vindo a sofrer alterações. Apenas uma coisa parece não ter mudado: os critérios de desempenho usados para avaliar esta teoria de investimento. Nos últimos anos, quando aplicados esses critérios de performance, a academia reparou que o investimento em valor apresentava um desempenho medíocre comparativamente àquilo a que tinha habituado o mercado e os investidores. Mas será que estes resultados podem ser cegamente aceites? Quando tudo parece ter mudado, fará sentido esperar resultados válidos, aplicando o mesmo critério a realidades completamente diferentes? É isso o que nos propomos descobrir. No presente trabalho forneceremos uma framework alternativa àquela que tem vindo a ser utilizada pela academia ao longo dos anos. Iremos expor alguns dos motivos que podem motivar esse (aparente) baixo desempenho, e alternativas para superar essas dificuldades. A nossa intenção é clara: avaliar se o investimento em valor realmente perdeu seu hedge, ou se, por outro lado, os académicos medem o desempenho desta teoria de investimento com critérios desatualizados e desajustados à realidade atual

    A 2D kinematic study of the NLR of the galaxy NGC 4151

    Get PDF
    Resumo nĂŁo disponĂ­ve

    Low-cost upconversion nanomaterials for anti-counterfeiting solutions

    Get PDF
    This work consisted on the production and characterization of low-cost upconversion (UC) nanoparticles based on zirconia oxides (ZrO2). The production was made by a hydrothermal process assisted by microwave irradiation, where 4 reagents were tested: sodium hydroxide, hexamethylenetetramine, urea and ethylenediamine. Ytterbium (Yb) and erbium (Er) were used as dopants to allow the upconversion process. The aim was that the nanoparticles would match photoluminescent characteristics of a detector provided by INCM (Imprensa Nacional – Casa da Moeda) so that it can be used as a security marker. Hexamethylenetetramine has proven to be the best reagent to reach the desired nanoparticles with a maximum size of 100 nm. It was concluded that no dispersant was necessary to stabilize the powder when added directly into the proper ink. Different synthesis parameters were tested to optimize the morphology and size of nanomaterials such as time, pH and temperature. It was also achieved the scale up production of this nanoparticles, since passing from 25 ml to 600 ml solutions did not alter the optical response. Both flexographic and screen printing were proven successful printing methods as the final luminescent outcome matched the marker characteristics. A cheaper, environmentally friendly and new marker was accomplished, allowing that more products may have a security mark, guaranteeing their final authenticity

    Legionella pneumophila

    Get PDF
    Legionella pneumophila is an intracellular pathogen, ubiquitous in the environment and considered opportunistic. It is the leading cause of legionellosis, which can be present in its nonpneumonic form (Pontiac fever) and acute pneumonic form (Legionnaires` disease – LD). In the soil and aquatic systems, L. pneumophila can invade and survive intracellularly in various protozoans. The ability to proliferate within biofilms provides additional protection from environmental stresses, such as disinfection. Human infection by L. pneumophila occurs after the inhalation or aspiration of aerosols containing the pathogen. Upon infection, alveolar macrophages can be invaded and used by L. pneumophila for replication, resembling the infection of protozoan hosts in the environment. The ability of L. pneumophila to overcome the killing mechanisms of phagocytes depends on the Dot/Icm type IV secretion system – a specialized protein translocation system vital for the intracellular survival of the pathogen and for establishing a replicative niche known as the Legionella-containing vacuole. Following host cell lysis, the released bacteria infect other host cells, beginning a new cycle of infection.This work was financially supported by Base Funding – UIDB/00511/2020 of LEPABE and funded by national funds through the FCT/MCTES (PIDDAC); Project Biocide_for_Biofilm – PTDC/BII-BTI/30219/2017 – POCI-01-0145-FEDER-030219, pBio4.0 – POCI-01-0247-FEDER-033298, funded by FEDER funds through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES; Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE 01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

    Copper surfaces in biofilm control

    Get PDF
    Biofilms are structures comprising microorganisms associated to surfaces and enclosed by an extracellular polymeric matrix produced by the colonizer cells. These structures protect microorganisms from adverse environmental conditions. Biofilms are typically associated with several negative impacts for health and industries and no effective strategy for their complete control/eradication has been identified so far. The antimicrobial properties of copper are well recognized among the scientific community, which increased their interest for the use of these materials in different applications. In this review the use of different copper materials (copper, copper alloys, nanoparticles and copper-based coatings) in medical settings, industrial equipment and plumbing systems will be discussed considering their potential to prevent and control biofilm formation. Particular attention is given to the mode of action of copper materials. The putative impact of copper materials in the health and/or products quality is reviewed taking into account their main use and the possible effects on the spread of antimicrobial resistance.This work was financially supported by: Base Funding—UIDB/00511/2020 of LEPABE and UIDB/00081/2020 of CIQUP funded by national funds through the FCT/MCTES (PIDDAC); Project Biocide_for_Biofilm—PTDC/BII-BTI/30219/2017—POCI-01-0145-FEDER-030219, ABFISH—PTDC/ASP-PES/28397/2017—POCI-01-0145-FEDER-028397 and ALGAVALOR—POCI-01-0247-FEDER-035234, funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES; Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte; SFRH/BSAB/150379/2019 (Manuel Simões).info:eu-repo/semantics/publishedVersio

    Influence of different copper materials on biofilm control using chlorine and mechanical stress

    Get PDF
    The selection of materials for plumbing application has potential implications on the chemical and microbiological quality of the delivered water. This work aims to evaluate the action of materials with different copper content (0, 57, 96 and 100%) on biofilm formation and control by chlorination and mechanical stress. A strain of Stenotrophomonas maltophilia isolated from drinking water was used as model microorganism and biofilms were developed in a rotating cylinder reactor (RCR) using realism-based shear stress conditions. Biofilms were characterized phenotypically and exposed to three control strategies: 10 mg/l of free chlorine for 10 min; an increased shear stress (equivalent to 1.5 m/s of fluid velocity); and the combination of both treatments. Biofilms formed on the copper materials had lower wet mass and produced significantly lower amounts of extracellular proteins than those formed on stainless steel (0% of copper content). Although, the effects of copper materials on biofilm cell density was not significant, these materials had important impact on the efficacy of chemical and/or mechanical treatments. Biofilms formed on 96 or 100% copper materials had lower content of culturable bacteria than that observed on stainless steel after exposure to chlorine or shear stress. The mechanical treatment used had no relevant effects in biofilm control. The combination of chemical and mechanical treatments only caused higher culturability reduction than chlorine in biofilms formed on 57% copper alloy. The number of viable cells present in bulk water after biofilm treatment with chlorine was lower when biofilms were formed on any of the copper surface. The overall results are of potential importance on the selection of materials for drinking water distribution systems, particularly for house and hospital plumbing systems to overcome the effects from chlorine decay. Copper alloys may have a positive public health impact by reducing the number of viable cells in the delivered water after chlorine exposure and improving the disinfection of DW systems. Moreover, the results demonstrate that residual chlorine and mechanical stress, two strategies conventionally used for disinfection of drinking water distribution systems, failed in S. maltophilia biofilm control.This work was the result of the projects: UIDB/00511/2020 of the Laboratory for ProcessEngineering, Environment, Biotechnology and Energy – LEPABE - funded by national funds throughthe FCT/MCTES(PIDDAC); PTDC/BII-BTI/30219/2017-POCI-01-0145-FEDER-030219;POCI-01-0145-FEDER-006939, funded by FEDER funds through COMPETE2020 – ProgramaOperacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) throughFCT/MCTES; NORTE-01-0145-FEDER-000005 – LEPABE-2-ECO-INNOVATION, supported by NortePortugal Regional Operational Programme (NORTE 2020), under PORTUGAL 2020 PartnershipAgreement, through the European Regional Development Fund (ERDF)info:eu-repo/semantics/publishedVersio

    The effects of different biocides against selected drinking water-isolated bacteria in planktonic and sessile states

    Get PDF
    The chemical disinfectant chlorine, as chlorine gas (Cl2) and sodium hypochlorite (NaOCl), has been commonly used for drinking water treatment.1,2 Although the recommended residual concentration of free chlorine allows to some extent the control of microbial growth in the bulk water, the occurrence of biofilms in chlorinated drinking water distribution systems (DWDS) has been frequently reported.3,4 Therefore, the main goal of this study was the study of alternative biocides to control biofilm development in DWDS. The effects of sodium dichloroisocyanurate (NaDCC), trichloroisocyanuric acid (TCCA), and pentapotassium bis(peroxymonosulphate) bis(sulphate) (OXONE®) were analysed against two emerging pathogens isolated from drinking water, Acinetobacter calcoaceticus and Stenotrophomonas maltophilia. The determination of the minimum bactericidal concentrations (MBC) of the selected biocides were based on the European Standard EN 1276, with MBC between 1.56 to 6.25 mg/L for NaDCC, 2.5 to 3.75 mg/L for TCCA, and 172 to 688 mg/L for OXONE®. Inactivation curves were developed and fitted to microbial survival models. The effects of biocides on cytoplasmic membrane integrity were assessed by propidium iodide uptake. The action on biofilm control was analysed against 48 h old biofilms developed on polyvinyl chloride (PVC) and stainless steel (SS) coupons using a 24-wells microtiter plate assay. The bacteria culturability and removal assessment were determined by colony forming units (CFU) enumeration on R2A agar, and by 4,6-diamidino-2-phenylindole (DAPI) staining, respectively. This study reinforces biofilms as chronic contaminants of DWDS and highlights that the understanding of antimicrobial susceptibility of microorganisms to biocides is an important step in the design of effective biofilm control strategies in order to provide to consumers drinking water of adequate microbiological quality.This work was financially supported by: Base Funding - UIDB/00511/2020 of the Laboratory forProcess Engineering, Environment, Biotechnology and Energy – LEPABE - funded by national fundsthrough the FCT/MCTES (PIDDAC); PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-030219;POCI-01-0145-FEDER-006939, funded by FEDER funds through COMPETE2020 – ProgramaOperacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES; and PhD grant awarded to Isabel Maria Oliveira (SFRH/BD/138117/2018).info:eu-repo/semantics/publishedVersio

    Computed Tomography in the Evaluation of Lung Transplant Chronic Rejection

    Get PDF
    Lung transplantation is an increasingly common therapeutic option in end-stage pulmonary diseases. One of the main causes of medium and long-term graft failure is chronic rejection, clinically represented by bronchiolitis obliterans syndrome. The early diagnosis of chronic rejection allows optimization of immunosuppressive therapy in order to delay its progression.In this paper, we review and illustrate the characteristics of chronic lung rejection in high-resolution computed tomography to promote its early diagnosis in follow-up examinations.At an early stage, during the first year after transplantation, subtle features such as reduction of peripheral bronchovascular markers, thickening of the septal lines, and decreased lung volumes may suggest the diagnosis even before clinical changes appear. Mid-term features are represented by bronchiectasis and bronchial wall thickening, and present low sensitivity, but high specificity in the diagnosis of chronic rejection. Its appearance occurs simultaneously with the clinical diagnosis of bronchiolitis obliterans syndrome. Lung attenuation abnormalities appear in late stages of the disease. Air trapping is related with small airway obstruction and mosaic attenuation pattern with ventilation-perfusion mismatch. Fibrotic changes of the lung parenchyma characterize advanced stages of chronic graft rejection, leading to important functional repercussion.High-resolution computed tomography has helped to overcome the limitations of clinical criteria in the diagnosis of obliterans bronchiolitis syndrome and promoted an earlier diagnosis of chronic rejection after lung transplantation

    Avaliar em educação física: a necessidade de um quadro conceptual

    Get PDF
    A avaliação é considerada parte integrante do processo educativo, imprescindível em qualquer proposta de educação. Esta encontra-se ligada ao processo ensino e aprendizagem, contudo sabemos que na prática pedagógica esta fica muitas vezes desvinculada neste processo. Muitas vezes a avaliação é apenas vista como uma mera atribuição de notas, dando aos alunos um ”rótulo” e não como um meio de o mesmo orientar a sua prática indo deste modo ao encontro das reais necessidades dos seus alunos. Consideramos que este tema é bastante complexo, contudo pretendemos compreender como a mesma pode ser um instrumento facilitador e de reflexão das práticas, buscando assim progredir na construção do conhecimento. A avaliação feita nos moldes tradicionais e sem qualquer objetivo parece-nos estar descontextualizada, estamos em crer que a mesma deve ser inovadora que leve o aluno a assimilar informações e utilizá-las em contextos adequados, de modo a que possa tomar decisões autónomas e criativas. O importante é a aprendizagem efetiva que existe. Mas se pensarmos na origem deste tema podemos compreender este pensamento, contudo está desatualizado e descontextualizado na nossa realidade. O mais importante é saber o que avaliar? Quem? Como? Porquê? E com que resultados. Neste sentido com esta comunicação procuramos mostrar a necessidade de um quadro conceptual, de modo a que todos possam saber qual o caminho a seguir e que opções tomar.N/
    • …
    corecore