249 research outputs found
Long-term memory in financial prices: evidence from the Dutch stock market returns
Prepared for presentation at the Portuguese Finance Network International Conference 2014, Vilamoura, Portugal, June 18-20The purpose of this paper is to contribute to the discussion of long-term memory, focusing on the behavior of the main Dutch stock index.The analysis of the general characteristics of temporal frequency reveals that daily returns are non-ergodic, non-stationary and non-independent. Consequently, we have employed the rescaled-range analysis (R/S) and the detrended fluctuation analysis (DFA), under the fractional Brownian motion approach, and found slight evidence of long-term persistence. This suggests that this market is more prone to predictability ("Joseph effect"), but also trends that may be unexpectedly disrupted by discontinuities ("Noah effect"). Although the evidence of fractal dynamics has weak support, refutes the hypothesis of random walk with i.i.d. increments. This implies that the use of statistical limit arguments to determine conventional financial statistics, as used in the Capital Asset Pricing Model and option valuation models, is scientifically incorrect. Furthermore, a more localized (in time) study to identify the evolution of the degree of long-term memory over time showed a change in the characteristic index from persistent to anti-persistent, more evident after 2010. This suggests that the AEX market does not correspond to Efficient Market Hypotheis in strictly sense of Fama (1970), although it has progressed closer to this theoretical ideal during the worsening of the current international financial crisis
Biosensor for direct bioelectrocatalysis detection of nitric oxide using nitric oxide reductase incorporated in carboxylated single-walled carbon nanotubes/lipidic 3 bilayer nanocomposite
An enzymatic biosensor based on nitric oxide reductase (NOR; purified from Marinobacter hydrocarbonoclasticus) was developed for nitric oxide (NO) detection. The biosensor was prepared by deposition onto a pyrolytic graphite electrode (PGE) of a nanocomposite constituted by carboxylated single-walled carbon nanotubes (SWCNTs), a lipidic bilayer [1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-di-(9Z-octadecenoyl)-3-trimethylammonium-propane (DOTAP), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol (DSPE-PEG)] and NOR. NOR direct electron transfer and NO bioelectrocatalysis were characterized by several electrochemical techniques. The biosensor development was also followed by scanning electron microscopy and Fourier transform infrared spectroscopy. Improved enzyme stability and electron transfer (1.96 × 10-4 cm.s-1 apparent rate constant) was obtained with the optimum SWCNTs/(DOPE:DOTAP:DSPE-PEG)/NOR) ratio of 4/2.5/4 (v/v/v), which biomimicked the NOR environment. The PGE/[SWCNTs/(DOPE:DOTAP:DSPE-PEG)/NOR] biosensor exhibited a low Michaelis-Menten constant (4.3 μM), wide linear range (0.44-9.09 μM), low detection limit (0.13 μM), high repeatability (4.1% RSD), reproducibility (7.0% RSD), and stability (ca. 5 weeks). Selectivity tests towards L-arginine, ascorbic acid, sodium nitrate, sodium nitrite and glucose showed that these compounds did not significantly interfere in NO biosensing (91.0 ± 9.3%-98.4 ± 5.3% recoveries). The proposed biosensor, by incorporating the benefits of biomimetic features of the phospholipid bilayer with SWCNT's inherent properties and NOR bioelectrocatalytic activity and selectivity, is a promising tool for NO.FG thanks to Fundacão para a Ciência e a Tecnologia, MCTES (FCT/MCTES) for the fellowship grant SFRH/BD/52502/2014, which is financed by national funds and co-financed by FSE. LBM thanks to FCT/MCTES for the CEEC-Individual 2017 Program Contract. This work was supported by the PTDC/BB-BQB/0129/2014 project (FCT/MCTES), by FCT/MEC with national funds and co-funded by FEDER, and also by the Associate Laboratory Research Unit for Green Chemistry - Technologies and Processes Clean – LAQV, financed by national funds from FCT/MCTES (UID/QUI/50006/2019). The financial support from the European Union (FEDER funds through COMPETE) and National Funds (Fundação para a Ciência e Tecnologia-FCT) through project PTDC/ASP-PES/29547/2017, by FCT/MEC with national funds and co-funded by FEDER, is also acknowledged. J.A. Loureiro post-doc grant was supported by NORTE-01-0145-FEDER-000005 – LEPABE-2 ECO-INNOVATION, from North Portugal Regional Operational Program (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio
Water treatment by multistage filtration system with natural coagulant from Moringa oleifera seeds
The BLue Amazon Brain (BLAB): A Modular Architecture of Services about the Brazilian Maritime Territory
We describe the first steps in the development of an artificial agent focused
on the Brazilian maritime territory, a large region within the South Atlantic
also known as the Blue Amazon. The "BLue Amazon Brain" (BLAB) integrates a
number of services aimed at disseminating information about this region and its
importance, functioning as a tool for environmental awareness. The main service
provided by BLAB is a conversational facility that deals with complex questions
about the Blue Amazon, called BLAB-Chat; its central component is a controller
that manages several task-oriented natural language processing modules (e.g.,
question answering and summarizer systems). These modules have access to an
internal data lake as well as to third-party databases. A news reporter
(BLAB-Reporter) and a purposely-developed wiki (BLAB-Wiki) are also part of the
BLAB service architecture. In this paper, we describe our current version of
BLAB's architecture (interface, backend, web services, NLP modules, and
resources) and comment on the challenges we have faced so far, such as the lack
of training data and the scattered state of domain information. Solving these
issues presents a considerable challenge in the development of artificial
intelligence for technical domains
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
XXX Jornadas Luso-Españolas de Gestión CientÃfica. Cooperación transfronteriza: desarrollo y cohesión territorial: libro de actas - Vol. III
As XXX Jornadas Luso-Espanholas de Gestão CientÃfica (XXX JLE 2020), que tinham como
tema principal ‘Cooperação transfronteiriça: desenvolvimento e coesão territorial’ decorreram
entre os dias 5 e 8 de fevereiro de 2020, com a participação de mais de 270 conferencistas.
Para além das mais de 200 comunicações apresentadas, envolvendo um total de 564
investigadores nacionais e internacionais, as XXXJLE 2020 contaram com a presença de
alguns distintos convidados, começando no dia 6 de fevereiro na Sessão com os editores
das revistas (Helena Alves, João Ferreira e António Navarro; Bernabé Escobar como
moderador) e no dia 7 de fevereiro com a Mesa-Redonda onde se refletiu sobre Cooperação
Transfronteiriça: Desenvolvimento e coesão territorial (Isabel Ferreira, Fernando Freire
de Sousa, Raquel Rocha, João Bule, José Luis Prieto e Paula Franco; Miguel André Cabral
como moderador). Foram, ainda, distinguidos 22 trabalhos cientÃficos que apresentaram
uma elevada qualidade cientÃfica. A todos, investigadores, conferencistas e convidados, se
fica a dever o êxito cientÃfico das XXX Jornadas Luso Espanholas de Gestão CientÃfica.
Os quatro volumes de atas que agora se publicam são fruto da totalidade das comunicações
dos investigadores apresentadas nas XXX JLE 2020, agrupadas em 19 capÃtulos, de
acordo com a sessão paralela em que foram apresentadas, cobrindo, assim, praticamente
todas as áreas das ciências empresariais: Administração Pública; Contabilidade; Desenvolvimento
Regional; Docência: Metodologia e Experiências docentes; Empreendedorismo;
Economia Social; Empresa Familiar; Estratégia; Ética e Responsabilidade Social; Finanças;
Fiscalidade; Gestão das Organizações sem Fins Lucrativos; Gestão de Desporto; Inovação e
Gestão do Conhecimento; Marketing; Organização de Empresas; Recursos Humanos;
Turismo; Jovens investigadores em ciências económicas e empresariais.
A Organização das XXX JLE 2020, a publicação do livro de resumos, a publicação do livro de
atas são o resultado do esforço conjunto de várias pessoas e instituições. Fica aqui
expresso o reconhecimento e gratidão à Presidência do Instituto Politécnico de Bragança, Ã
Direção da Escola Superior de Tecnologia e Gestão e à Câmara Municipal de Bragança
pelas condições logÃsticas proporcionadas e por todo o apoio recebido, à Pró-Presidência
para a Comunicação e aos Serviços de Imagem do IPB, à Fundação para a Ciência e a
Tecnologia e à Unidade de Investigação Aplicada em Gestão (UNIAG), a todas as entidades
públicas e privadas que patrocinaram a realização das XXX JLE 2020, a todos os membros
das Sessões de Abertura e de Encerramento das XXX JLE 2020, a todos os membros da
Comissão CientÃfica (Portuguesa e Espanhola), aos conferencistas, aos investigadores e aos
moderadores das diferentes sessões, pela excelente qualidade dos trabalhos apresentados
e pelo rigor e profundidade com que os diversos temas foram abordados e discutidos. Por
último, mas não menos importante, à Comissão Organizadora e respetivo Staff por
aceitarem mais este desafio e por ‘viajarem’ comigo nesta longa, árdua, mas profÃcua
jornada e por todo o suporte desde o primeiro minuto, o meu Muito Obrigada!
A finalizar e em nome da Comissão Organizadora gostaria de expressar o nosso voto final e
desejar que estas Jornadas Luso-Espanholas de Gestão CientÃfica continuem a ter todo o
êxito e força que têm vindo a demonstrar, a ensinar e que proporcionem não só, momentos
de reflexão e debate sobre as questões mais prementes para e no futuro, bem como a
discussão de novos desafios e oportunidades de cooperação em rede, transferência e
partilha de conhecimento.Financiado por UNIAG, unidade de I&D financiada pela FCT – Fundação para a ciência e a
Tecnologia, Ministério da Ciência, Tecnologia e Ensino Superior, no âmbito do Projeto n.º UIDP/04752/2020.info:eu-repo/semantics/publishedVersio
Levels of diphtheria and tetanus specific IgG of Portuguese adult women, before and after vaccination with adult type Td. Duration of immunity following vaccination
<p>Abstract</p> <p>Background</p> <p>The need for tetanus toxoid decennial booster doses has been questioned by some experts. Several counter arguments have been presented, supporting the maintenance of decennial adult booster doses with tetanus and diphtheria toxoids (adult formulation of the vaccine: Td). This study aimed to evaluate the use of Td in Portuguese adult women under routine conditions. For that purpose we selected a group of women 30+ years of age to which vaccination was recommended. We intended to know if pre-vaccination antibody concentrations were associated with factors as age at first and last vaccination, number of doses and time since last revaccination. We also intended to assess the serological efficacy of Td booster.</p> <p>Methods</p> <p>Following the Portuguese guidelines 100 women were vaccinated with Td. Antitetanus toxin IgG (ATT IgG) and antidiphtheria toxin IgG (ADT IgG) levels were measured (mIU/ml) in 100 pre-vaccination and 91 post-vaccination sera. Detailed vaccination records were available from 88 participants.</p> <p>Results</p> <p>Twenty-two women (Group A) began vaccination with DPT/DT in their early childhood and their pre-vaccination ATT IgG levels increased with the number of doses received (p = 0.022) and decreased with time since last vaccination (p = 0.016). Among the 66 women who began vaccination in adolescence and adulthood (Group B), with monovalent TT, ATT IgG levels decreased with age at first dose (p < 0.001) and with time since last vaccination (p = 0.041). In Group A, antidiphtheria toxin IgG kinetics was very similar to that observed for ATT IgG. Among women not vaccinated with diphtheria toxoid, ADT IgG levels decreased with age. Serological response to both components of Td was good but more pronounced for ATT IgG.</p> <p>Conclusion</p> <p>Our study suggests that, to protect against tetanus, there is no need to administer decennial boosters to the Portuguese adults who have complied with the childhood/adolescent schedule (6 doses of tetanus toxoid). The adult booster intervals could be wider, probably of 20 years. This also seems to apply to protection against diphtheria, but issues on the herd immunity and on the circulation of toxigenic strains need to be better understood.</p
A comprehensive assessment of the transcriptome of cork oak (Quercus suber) through EST sequencing
Background: Cork oak (Quercus suber) is one of the rare trees with the ability to produce cork, a material widely used to make wine bottle stoppers, flooring and insulation materials, among many other uses. The molecular mechanisms of cork formation are still poorly understood, in great part due to the difficulty in studying a species with a long life-cycle and for which there is scarce molecular/genomic information. Cork oak forests are of great ecological importance and represent a major economic and social resource in Southern Europe and Northern Africa. However, global warming is threatening the cork oak forests by imposing thermal, hydric and many types of novel biotic stresses. Despite the economic and social value of the Q. suber species, few genomic resources have been developed, useful for biotechnological applications and improved forest management.
Results: We generated in excess of 7 million sequence reads, by pyrosequencing 21 normalized cDNA libraries derived from multiple Q. suber tissues and organs, developmental stages and physiological conditions. We deployed a stringent sequence processing and assembly pipeline that resulted in the identification of ~159,000 unigenes. These were annotated according to their similarity to known plant genes, to known Interpro domains, GO classes and E.C. numbers. The phylogenetic extent of this ESTs set was investigated, and we found that cork oak revealed a significant new gene space that is not covered by other model species or EST sequencing projects. The raw data, as well as the full annotated assembly, are now available to the community in a dedicated web portal at http://www.corkoakdb.org.
Conclusions: This genomic resource represents the first trancriptome study in a cork producing species. It can be explored to develop new tools and approaches to understand stress responses and developmental processes in forest trees, as well as the molecular cascades underlying cork differentiation and disease response.Peer Reviewe
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