Enhancement of dibenzothiophene desulfurization by Gordonia alkanivorans strain 1B using sugar beet molasses as alternative carbon source

There are several problems limiting an industrial application of fossil fuel biodesulfurization, and one of them is the cost of culture media used to grow the microorganisms involved in the process. In this context, the utilization of alternative carbon sources resulting from agro-industrial by-products could be a strategy to reduce the investment in the operating expenses of a future industrial application. Recently, Gordonia alkanivorans 1B was described as a fructophilic desulfurizing bacterium, and this characteristic opens a new interest in alternative carbon sources rich in fructose. Thus, the goal of this study was to evaluate the utilization of sugar beet molasses (SBM) in the dibenzothiophene (DBT) desulfurization process using strain 1B. SBM firstly treated with 0.25 % BaCl2 (w/v) was used after sucrose acidic hydrolysis or in a simultaneous saccharification and fermentation process with a Zygosaccharomyces bailii Talf1 invertase (1 %), showing promising results. In optimal conditions, strain 1B presented a ìmax of 0.0795 h.1, and all DBT was converted to 2-hydroxybiphenyl (250 ìM) within 48 h with a maximum production rate of 7.78 ìM h.1. Our results showed the high potential of SBM to be used in a future industrial fossil fuel biodesulfurization process using strain 1B

Price Clustering in Bank Stocks during the Global Financial Crisis

Market anomalies are one of the most intriguing and fascinating phenomena observed in financial markets. This paper examines the incidence of price clustering in US and European bank stocks during the Global Financial Crisis. The results reveal a significant level of price clustering in European and US banks’ samples, which is difficult to reconcile with the Efficient Market hypothesis. The Attraction hypothesis and the Price Resolution/Negotiation hypothesis seem to be the best explanations for the clustering effect. However, the results also suggest that the uncertainty associated with the crisis did not have a significant impact in the clustering levels, which is at odds with the recently proposed Panic Trading hypothesis. Surprisingly, we observe a tendency to have less price clustering during the period of crisis and banks located in countries mostly affected by the European sovereign debt crisis exhibit lower levels of price clustering. These results are consistent with the idea that investors tend to be more analytical in their appraisals in periods of negative sentiment.JEL Codes - G12; G14; G01; G

Acute toxicity evaluation of several compounds involved in fossil fuels biodesulphurisation studies

The increasing use of fossil fuels has led to increased emissions of sulphur oxides into the air, which is a major cause of acid rain. Legislation already adopted in 2009 stipulates that the maximum level of sulphur allowed in fuels is only 10 ppm. The process of hydrodesulphurization (HDS) used in refineries is based on very expensive physico-chemical techniques, and has limitations in the removal of organic sulphur. As for stricter legislation on the maximum levels of sulphur in fossil fuels, the most HDS recalcitrant compounds needs to be removed. This implies an increase in the intensity of the physical-chemical treatment and inherently its associated costs. As a result, the recalcitrant compounds to HDS represent a significant barrier to the achievement of very low levels of sulphur in some petroleum fractions. The alternative to the physical-chemical treatment could be the use of biological processes (biodesulphurisation) which is more effective for the desulphurization of fossil fuels, especially as the removal of sulphur covalently bound to organic matrices. The biodesulphurisation (BDS) occurs in more mild conditions of operation under conditions of atmospheric pressure and temperature, giving greater specificity of reaction due to the nature of the biocatalysts, not requiring molecular hydrogen. Thus, in the last 15 years there has been an increase of studies involving the use of microorganisms with the ability to specifically remove the HDS recalcitrant sulphur compounds. Several model compounds such as dibenzothiophene (DBT), DBT sulphone or benzothiophene (BT) are used in BDS studies to characterise organic sulphur in coal, coal tars and crude oils. The desulphurising microorganisms are able to remove the sulphur atom from these compounds and use it in their metabolism. However, such compounds are very toxic to the cells. The aim of this work was to evaluate the toxicity of several compounds used in BDS studies, such as DBT and its derivatives and organic solvents used to dissolve these hydrocarbons, to two typical desulphurising strains, namely: Gordonia alkanivorans strain 1B and Rhodococcus eritropolis strain D1. The toxicity bioassays evaluated the inhibitory effect of the studied compounds to the described bacteria by measuring the respiration rate (mg O2/l) under defined conditions in the presence of different concentrations of those compounds. The inhibitory or toxic effect of each chemical at a specific concentration is expressed as a percent of the baseline respiration rate. From these results the several IC50s were estimated and are described in Table 1. These toxicity values showed that strain 1B was less sensitive for almost all of the hydrocarbons, which is an important advantage considering the desulphurisation of fossil fuels process. On the other hand, strain 1B was more sensitive to dimethylformamide (DMF), a typical solvent used in BDS studies. However, a good correlation can be observed between IC50-1B versus IC50-D1 (IC50-D1 = 0.504 x IC50-1B + 2.84; r2 = 0.908, p < 0.05)

O espaço curricular da história da educação na Faculdade de Letras do Porto (1961-2013)

A História da Educação desde que foi introduzida no ensino superior e até 1974 esteve sempre ligada à formação psicopedagógica dos professores do ensino secundário, formação essa que teve início nos primeiros anos do século XX, no Curso de habilitação para o Magistério Secundário do Curso Superior de Letras que durante a Iª República foi ministrado nas Escolas Normais Superiores e que de 1930 a 1974 foi ministrado nos Cursos de Ciências Pedagógicas. A reabertura da Faculdade de Letras da Universidade do Porto em 1961, permitiu recuperar a cadeira de História da Educação, seja integrante do Curso de Ciências Pedagógicas no âmbito da preparação para a docência, seja como disciplina de opção da licenciatura em História. A análise dos conteúdos permite-nos realçar quatro ideias: o seu conteúdo privilegia a perspetiva cronológica, embora excecionalmente surja uma vertente mais temática; a lógica descritiva sobrepõe-se enfatizando as ideias, os projetos e os factos educativos; a incidência cronológica é no período contemporâneo (séculos XVIII a XX); há uma maior incidência na perspetiva nacional, surgindo o quadro comparativo com o internacional, muito pontualmente. A docência esteve apenas entregue a cinco docentes e foi possível verificar que só na década de 1980 houve alguma alteração ao nível dos programas, dos processos pedagógico-didáticos e da sua inserção curricular com caraterísticas opcionais.Aliás é em 1984 que se realiza pela primeira vez um concurso de agregação para a cadeira de História da Educação e justamente na Faculdade de Letras do Porto, por intermédio do docente Francisco Fortunato Queirós. Nessa altura, questionava-se muito o espaço epistemológico da História da Educação no âmbito das Ciências da Educação e qual o seu lugar/espaço no conjunto das disciplinas de formação psicopedagógica dos professores do ensino básico e secundário. Depois de mais de uma década de ausência, a disciplina volta a aparecer como opção na licenciatura em História em 2013-2014 , com inscrição de estudantes de outras Faculdades, em particular daqueles que pretendem seguir Mestrados em Ensino.Pretende-se com esta incursão investigativa: compreender o percurso da História da Educação na instituição Faculdade de Letras do Porto; analisar a evolução dos seus conteúdos programáticos e da metodologia de lecionação/avaliação; verificar, sempre que existam dados, o público discente e as suas motivações para a frequência da cadeira; comparar o seu percurso no Porto com o de outras universidades, em particular de Lisboa, onde, 10 anos depois, voltamos a encontrar provas de agregação com base em um relatório desta disciplina (António Nóvoa)

Ability of Gordonia alkanivorans strain 1B for high added value carotenoids production

Currently, carotenoids are valuable bioactive molecules for several industries, such as chemical, pharmaceutical, food and cosmetics, due to their multiple benefits as natural colorants, antioxidants and vitamin precursors. Hence, the increasing interest on these high added-value products has led to the search of alternatives, more cost-effective and with better yields, towards their industrial production. Indeed, microbial metabolism offers a promising option for carotenoids production. Herein it is shown the potential of the dibenzothiophene desulfurizing bacterium Gordonia alkanivorans strain 1B as a high carotenoid-producer microorganism. The novel carotenoids, produced under different culture conditions, were extracted with DMSO and then further analyzed both through spectrophotometry and HPLC. When grown in glucose-sulfate-light, strain 1B was able of achieving 2015 g carotenoids per g DCW in shake-flask assays, with about 60% corresponding to lutein, canthaxanthin and astaxanthin. Further optimization studies open a new focus of research aiming to get a hyper pigment-producer strain that may be applied towards different industrial sectors

Implementation of a Private Cloud

The exponential growth of hardware requirements coupled with online services development costs have brought the need to create dynamic and resilient systems with networks able to handle high-density traffic. One of the emerging paradigms to achieve this is called Cloud Computing it proposes the creation of an elastic and modular computing architecture that allows dynamic allocation of hardware and network resources in order to meet the needs of applications. The creation of a Private Cloud based on the OpenStack platform implements this idea. This solution decentralizes the institution resources making it possible to aggregate resources that are physically spread across several areas of the globe and allows an optimization of computing and network resources. With this in mind, in this thesis a private cloud system was implemented that is capable of elastically leasing and releasing computing resources, allows the creation of public and private networks that connect computation instances and the launch of virtual machines that instantiate servers and services, and also isolate projects within the same system. The system expansion should start with the addition of extra nodes and the modernization of the existing ones, this expansion will also lead to the emergence of network problems which can be surpassed with the integration of Software Defined Network controllers