Modelação da curva de potência no contexto da detecção de anomalias em turbinas eólicas

Atualmente é muito importante saber o estado de condição de uma máquina. Com o desenvolvimento da tecnologia e da complexidade desta, a dificuldade na verificação do estado de funcionamento também tem crescido. Consequentemente, a busca de novas ideias para resolver este problema tem aumentado. As turbinas eólicas são exemplos destas máquinas. Com o crescimento da preocupação com as alterações climáticas, o seu uso tem aumentado consideravelmente. Em busca de novas maneiras de determinar a condição de funcionamento de uma turbina eólica sem interromper o seu funcionamento surgiu o tema deste trabalho que tem como objetivo a monitorização do estado de condição de uma turbina através da sua curva de potência. Este trabalho tem base em técnicas que se enquadram no âmbito da inteligência computacional. Para tal, será feita uma análise semanal onde a curva de potência de uma dada semana será comparada com a curva de potência estimada por um modelo de regressão criado ou ajustado com os dados previamente observados em períodos classificados como sendo representativos de bom estado de funcionamento. Algumas tentativas serão realizadas para tentar aperfeiçoar o modelo com o intuito de obter melhores resultados no final. Serão ainda testados diferentes blocos de dados de treino para verificar qual o melhor conjunto de variáveis de treino para ser usado pelo programa com o intuito de avaliar o estado de condição do equipamento. No final, foi possível identificar anomalias a partir da diferença das curvas de potência e justificar as diferenças com base na forma da curva ou com o número de observações nos blocos de dados usados na previsão

Synergistic Activity of Cymbopogon citratus and Mentha piperita Essential Oils against the Pinewood Nematode

The pinewood nematode (PWN) Bursaphelenchus xylophilus is a major threat to pine forests. Research on sustainable pest management strategies is now a priority. Essential oils (EOs) are biodegradable, complex mixtures of volatiles that can show low toxicity to mammals and powerful nematicidal activities depending on their chemical composition. In the present work, the EOs of four plants were screened against the PWN, solely and in combination to identify possible synergistic interactions. The combination of Cymbopogon citratus and Mentha piperita EOs (1:1) resulted in higher activities than those of each tested solely, suggesting the occurrence of synergistic interactions between the compounds of these EOs. Research on the combination of synergistic EOs may lead to the development of plant based biopesticides with optimized activities against the PWN

A relação das famílias com a escola : um olhar sobre a escolha da escola secundária : um estudo de caso

Tese de mestrado em Ciências da Educação (Área de especialização em Administração Educacional), apresentada à Universidade de Lisboa, através da Faculdade de Psicologia e de Ciências da Educação, 2006Com relevo para as duas últimas décadas do século XX, a crise do Estado Providência, a emergência de políticas neo-liberais e, a globalização da economia, entre outros fenómenos, tem levado ao despontar de novas formas de regulação do sistema educativo, com destaque para lógica da regulação mercantil. Neste estudo propomo-nos a perceber a forma como os EE se relacionam com a Escola, e se as suas práticas corroboram a lógica da regulação mercantil. A primeira parte deste trabalho, é constituída pelo enquadramento teórico, onde é feito um percurso sintético pelas tendências que a nível internacional e em Portugal, têm marcado a evolução das políticas educativas que conduziram ao reforço da presença dos pais nos órgãos da escola e, à implementação de medidas conducentes à livre escolha de escola. A segunda parte é relativa ao dispositivo empírico montado para a consecução desta investigação e que usou como recursos o inquérito por questionário, bem como ferramentas da estatística descritiva e da inferência estatística disponíveis no programa informático SPSS. Os resultados levam-nos a concluir que relativamente às formas de participação legalmente instituídas, o envolvimento dos EE é pautado por uma certa passividade. No entanto, no que diz respeito ao envolvimento dos EE ao longo do processo educativo dos seus educandos, é nítido o seu envolvimento na valorização dos saberes da Escola e no apoio e incentivo na obtenção de um certificado escolar. Por outro lado, esta participação informal também é patente na forma como os EE procedem à escolha da escola secundária, levando-nos a perceber a existência de processos informais de livre escolha de escola.Dans les dernières décennies du vingtième siècle, la crise de L ’État de Providence, l’émergence de politiques néo-libérales et la globalisation de l’économie, entre autres phénomènes a provoqué la création de nouvelles formes de régulation du système éducatif, en donnant plus importance à la logique de la régulation mercantile. Dans cette étude nous voulons comprendre la façon dont les parents font des connaissances avec L ’École, et si leurs pratiques soutiennent la logique de la régulation mercantile. La première partie de cette étude, a l’encadrement théorique, où on fait un parcours tout à fait résumé par les tendances qui, au niveau international et au Portugal aussi, ont marqué l’évolution des politiques éducatives qui ont menées à l’augmentation de la présence des parents dans les organes représentatifs de l’école et a l’implémentation de mesures conduisant au choix libre d ’école. La seconde partie concernant de dispositif empirique pour la consécution de cette investigation et qui a utilisé comme recours l’enquête, aussi comme des outils de statistique descriptive et l’inférence statistique disponibles dans un programme informatique le SPSS. Les résultats nous ont mené à la conclusion que en ce qui concerne aux formes de participation légalement institutionnalisées, l’enveloppement des parents est caractérisé par une certaine passivité. Cependant l’enveloppement des parents tout au long du procès éducatif de leurs enfants, il est notable leur enveloppement dans la valorisation des savoirs de L ’École et l’appui et incitation dans l'obtention d ’un certificat de l’école. D ’un autre côté, cette participation informelle est aussi présente dans la façon dont les parents choisissent l’école secondaire, en nous menant à comprendre l’existence de phénomènes informels du choix libre d ’école.With special emphasis to the last two decades of the twentieth century the crisis of the Welfare State, the appearing of neo-liberal policies and the globalization of the economy among other phenomena, has lead to the rise of new ways of regulating the educational system, focusing mostly on the logic of the mercantile regulation. With this study we want to understand the way parents put themselves in connection with school and if the ways they behave support the logic of the mercantile regulation. The first part of this study deals with the theoretical setting where we make a birds eye view of the tendencies that have marked the evolution of educational policies, both at an international level and in Portugal, and which have lead to the reinforcement of the presence of parents in the school departments and to the implementation of measures leading to the free school choice. The second part is related to the empiric work set for the consecution of this study and which used as resources not only the survey but also tools on the field of descriptive statistics and statistic inference available in SPSS. The results help us come to the conclusion that with regard to the ways of participation legally instituted, parents’ involvement is characterised by some passivity. However, regarding those parents’ involvement throughout the educational process of their children their involvement in the importance of the knowledge provided by the school is quite obvious. The same applies to their support and contribution to their children’s final school diploma. On the other hand, this informal collaboration can also be seen in the ways parents choose the secondary school they want their children to attend, which enable us to detect informal phenomena behind the free school choice

Pre-diabetes alters testicular PGC1-α/SIRT3 axis modulating mitochondrial bioenergetics and oxidative stress

Pre-diabetes, a risk factor for type 2 diabetes development, leads to metabolic changes at testicular level. Peroxisome proliferator-activated receptor γ coactivator 1α(PGC-1α) and Sirtuin 3 (Sirt3) are pivotal inmitochondrial function. We hypothesized that pre-diabetes disrupts testicular PGC-1α/Sirt3 axis, compromising testicular mitochondrial function. Using a high-energy-diet induced pre-diabetic rat model, we evaluated testicular levels of PGC-1α and its downstream targets, nuclear respiratory factors 1 (NRF-1) and 2 (NRF-2),mitochondrial transcription factor A (TFAM) and Sirt3.We also assessedmitochondrial DNA (mtDNA) content, mitochondrial function, energy levels and oxidative stress parameters. Protein levels were quantified by Western Blot, mtDNA contentwas determined by qPCR.Mitochondrial complex activity and oxidative stress parameterswere spectrophotometrically evaluated. Adenine nucleotide levels, adenosine and its metabolites (inosine and hypoxanthine) were determined by reverse-phase HPLC. Pre-diabetic rats showed increased blood glucose levels and impaired glucose tolerance. Both testicular PGC-1α and Sirt3 levels were decreased. NRF-1, NRF-2 and TFAM were not altered. Testicular mtDNA content was decreased. Mitochondrial complex I activity was increased, whereas mitochondrial complex III activity was decreased. Adenylate energy charge was decreased in pre-diabetic rats, as were ATP and ADP levels. Conversely, AMP levels were increased, evidencing a decreased ATP/AMP ratio. Concerning to oxidative stress pre-diabetes decreased testicular antioxidant capacity and increased lipid and protein oxidation. In sum, pre-diabetes compromises testicular mitochondrial function by repressing PGC-1α/Sirt3 axis and mtDNA copy number, declining respiratory capacity and increasing oxidative stress. This study gives newinsights into overall testicular bioenergetics at this prodromal stage of disease.This work was supported by the Portuguese “Fundação para a Ciência e a Tecnologia”—FCT, co-funded by FEDER via Programa Operacional Factores de Competitividade—COMPETE/QREN (PTDC/ QUI-BIQ/121446/2010 and PEst-C/SAU/UI0709/2011). L. Rato (SFRH/ BD/72733/2010), A. I. Duarte (SFRH/BPD/26872/2006) and M. G. Alves (SFRH/BPD/80451/2011) were financed by FCT and European Social Fund. P. F. Oliveira was financed by FCT through FSE and POPH funds (Programa Ciência 2008)

Nematicidal Activity of Oxygen-Containing Aliphatic Compounds on <i>Bursaphelenchus xylophilus</i>, <i>B. mucronatus</i> and <i>B. fraudulentus</i>

The pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of pine-wilt disease (PWD), is a threat to Pinus forests in Asia and Europe. Bursaphelenchus mucronatus and B. fraudulentus are closely related non-pathogenic pine-wood nematodes. In the present work, four medium-chain aliphatic alcohols (C10 to C13) were evaluated in direct-contact bioassays against B. xylophilus, B. mucronatus and B. fraudulentus. The compounds showed high nematicidal activity against the species tested. The lowest values for half-maximal effective concentrations (EC50) were determined in B. xylophilus and B. fraudulentus, suggesting a higher sensibility to these compounds. Further bioassays will include compounds with different chain lengths and functional groups to explore the diversity in the activity of oxygen-containing aliphatic compounds for a more targeted sustainable-control strategy for the PWN

Nematicidal Activity of Phytochemicals against the Root-Lesion Nematode <i>Pratylenchus penetrans</i>

Plant-parasitic nematodes (PPNs) are highly damaging pests responsible for heavy losses in worldwide productivity in a significant number of important plant crops. Common pest management strategies rely on the use of synthetic chemical nematicides, which have led to serious concerns regarding their impacts on human health and the environment. Plant natural products, or phytochemicals, can provide a good source of agents for sustainable control of PPNs, due to their intrinsic characteristics such as higher biodegradability, generally low toxicity for mammals, and lower bioaccumulation in the environment. In this work, the nematicidal activity of 39 phytochemicals was determined against the root-lesion nematode (RLN) Pratylenchus penetrans using standard direct and indirect contact methodologies. Overall, the RLN was tolerant to the tested phytochemicals at the highest concentration, 2 mg/mL, seldom reaching full mortality. However, high activities were obtained for benzaldehyde, carvacrol, 3-octanol, and thymol, in comparison to other phytochemicals or the synthetic nematicide oxamyl. These phytochemicals were seen to damage nematode internal tissues but not its cuticle shape. Also, the environmental and (eco)toxicological parameters reported for these compounds suggest lower toxicity and higher safety of use than oxamyl. These compounds appear to be good candidates for the development of biopesticides for a more sustainable pest management strategy