1,935 research outputs found

    Dcmc as a promising alternative to bentonite in white wine stabilization. Impact on protein stability and wine aromatic fraction

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    Funding Information: Funding: This research was funded by Associate Laboratory for Green Chemistry—LAQV, which is financed by national funds from FCT/MCTES [UID/QUI/50006/2020] and the project [UIDB/05183/2020], CENSE (Center for Environmental and Sustainability Research), which is financed by national funds from FCT/MCTES (UID/AMB/04085/2020), and LEAF, which is financed by national funds from FCT/MCTES (LEAF UID/AGR/04129/2020). This research was also anchored by the RESOLUTION LAB, an infrastructure at NOVA School of Science and Technology. DG was financed by a PhD grant: DFA/BD/5529/2020.Protein haze in white wine is one of the most common non-microbial defects of commercial wines, with bentonite being the main solution utilized by the winemaking industry to tackle this problem. Bentonite presents some serious disadvantages, and several alternatives have been pro-posed. Here, an alternative based on a new cellulose derivative (dicarboxymethyl cellulose, DCMC) is proposed. To determine the efficiency of DCMC as a bentonite alternative, three monovarietal wines were characterized, and their protein instability and content determined by a heat stability test (HST) and the Bradford method, respectively. The wines were treated with DCMC to achieve stable wines, as shown by the HST, and the efficacy of the treatments was assessed by determining, before and after treatment, the wine content in protein, phenolic compounds, sodium, calcium, and volatile organic compounds (VOCs) as well as the wine pH. DCMC applied at dosages such as those commonly employed for bentonite was able to reduce the protein content in all tested wines and to stabilize all but the Moscatel de Setúbal varietal wine. In general, DCMC was shown to induce lower changes in the wine pH and phenolic content than bentonite, reducing the wine calcium content. Regarding which VOCs are concerned, DCMC produced a general impact similar to that of bentonite, with differences depending on wine variety. The results obtained suggest that DCMC can be a sustainable alternative to bentonite in protein white wine stabilization.publishersversionpublishe

    DCMC as a promising alternative to bentonite in white wine stabilization. Impact on protein stability and wine aromatic fraction

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    Protein haze in white wine is one of the most common non-microbial defects of commercial wines, with bentonite being the main solution utilized by the winemaking industry to tackle this problem. Bentonite presents some serious disadvantages, and several alternatives have been proposed. Here, an alternative based on a new cellulose derivative (dicarboxymethyl cellulose, DCMC) is proposed. To determine the efficiency of DCMC as a bentonite alternative, three monovarietal wines were characterized, and their protein instability and content determined by a heat stability test (HST) and the Bradford method, respectively. The wines were treated with DCMC to achieve stable wines, as shown by the HST, and the efficacy of the treatments was assessed by determining, before and after treatment, the wine content in protein, phenolic compounds, sodium, calcium, and volatile organic compounds (VOCs) as well as the wine pH. DCMC applied at dosages such as those commonly employed for bentonite was able to reduce the protein content in all tested wines and to stabilize all but the Moscatel de Setúbal varietal wine. In general, DCMC was shown to induce lower changes in the wine pH and phenolic content than bentonite, reducing the wine calcium content. Regarding which VOCs are concerned, DCMC produced a general impact similar to that of bentonite, with differences depending on wine variety. The results obtained suggest that DCMC can be a sustainable alternative to bentonite in protein white wine stabilizationinfo:eu-repo/semantics/publishedVersio

    Resolving cryptic species complexes in Diplodia

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    Mestrado em Engenharia Agronómica - Instituto Superior de AgronomiaWhile the taxonomy and pathology of Botryosphaeria and Neofusicoccum has been studied intensively, Diplodia has several taxonomic problems that need to be resolved. This genus contains well-known plant pathogens including D. pinea (blight on pine trees), D. corticola (canker and dieback of cork oak) and D. mutila and D. seriata, which occur on a wide range of hosts. This suggests that these two species may in fact represent species complexes. The aim of this work was to resolve these cryptic species complexes - species that are morphologically indistinguishable and can be only separated at the phylogenetic level. Isolates were characterized on the basis of their micromorphology, including conidial dimensions, shape, pigmentation and septation, colony morphology and mycelial growth rate. Phylogenetic relationships were determined, firstly by microsatellite fingerprinting and then through analysis of ITS nucleotide sequences, supplemented with partial sequences of the translation elongation factor 1-α and β-tubulin genes. By integrating morphological characters with phylogenetic data several species were resolved within the Diplodia mutila complex, two new species (D. bulgarica and D. intermedia) were described, the status of D. fraxini and D. malorum was clarified and it was revealed that the D. pinea group may also be a complex of species

    Road Motion Control Electric Vehicle with Speed and Torque Observer

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    This paper presents an electric vehicle (EV) with two independent rear wheel drives and with an electric differential system. A model of the vehicle dynamic model is presented. The electric differential was implemented assuring that, in straight right trajectory, the two wheels drives roll exactly at same velocity and, in curve, the difference between the two velocities assure a vehicle trajectory. A speed and torque observer for DC motor was also proposed and simulated. Analysis and simulation results of the proposed system are presented.Com o apoio RAADRI

    Seismostratigraphic model of the Sines contourite drift (SW portuguese margin) - depositional evolution, structural control and paleoceanographic implications

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    Tese de mestrado, Geologia (Estratigrafia, Sedimentalogia e Paleontologia) Universidade de Lisboa, Faculdade de Ciências, 2017The Sines Contourite Drift, located in the Southwest Portuguese margin, is a distal drift of the Contourite Depositional System of the Gulf of Cadiz, built by the influence of the Mediterranean Outflow Water (MOW). This drift is located between 1000 and 2000 m water depth on the Alentejo margin continental slope. The Sines Drift is bounded by four major morphologic features: the 1.4 km high Pereira de Sousa Fault escarpment to the west, the upper continental slope to the east and the Setúbal and São Vicente canyons to the north and south, respectively. This work presents a seismic stratigraphic analysis and proposes an evolutionary model for the Sines Drift, as well as the identification of its main driving mechanisms and constraints. In pursuing such objectives, the following dataset was used: i) new and unpublished seismic reflection profiles acquired during the MOWER/CONDRIBER cruise in September-October 2014; ii) pre-existent multichannel seismic profiles BIGSETS, STEAM and GSI; iii) SWIM multibeam bathymetry; iv) lithostratigraphic and chronological data from Site U1391 of IODP (Integrated Ocean Drilling Program) Expedition 339 carried out in 2011-2012. Three evolutionary phases are identified for the Sines Drift development: 1) a sheeted-contourite-drift phase (<5.3-3.2 Ma) built since the Late Miocene by an initially weak flowing MOW; 2) a mounded-contourite-drift phase (3.2-0.7 Ma) from Late Pliocene to Early Quaternary times characterized by a mounded drift in the south and sheeted in the north, with a succession of sinuous N-S paleomoats in the east built as a result of a MOW enhancement; and 3) a plastered-contourite-drift phase from Mid-Pleistocene (0.7 Ma) till the present-day, characterized by the present depositional (sandy-muddy drifts) and erosional (moats) contourite features associated with two major events of MOW intensification. The growth of the Sines Drift was constrained by seafloor paleomorphologies that resulted from the rifting processes of the Southwest Portuguese margin, inherited from the Mesozoic rifting phases. The paleomorphologies provided accommodation space for drift growth and conditioned its overall architecture. The N-S horsts and grabens built during the Mesozoic rifting confined drift deposition and did not allow its lateral migration. The formation of the Sines Drift has also been influenced by climatic fluctuations and sea-level changes especially during the Quaternary. The succession of sinuous paleomoats beneath the present-day moat suggests a persistent and northward flowing MOW with several phases of enhancement. It was also perceived that the São Vicente and Setúbal canyons took most of the downslope sediment supply, as well as the occurrence of mass-movement processes in the west associated with the steep gradient of the Pereira de Sousa escarpment. All these results suggest the Sines Drift had a complex evolution controlled by several factors at different scales.Contornitos são corpos sedimentares depositados ou retrabalhados por correntes de fundo que circulam paralelamente aos contornos batimétricos da margem. A formação dos contornitos é afetada, a longo e curto prazo, por fatores externos e/ou internos que podem modificar o padrão de circulação das correntes. Os depósitos contorníticos podem atingir dimensões consideráveis com vários quilómetros de largura e comprimento, os quais conservam informação paleoclimática e paleoceanográfica. Os contornitos também desempenham um papel importante no estudo dos riscos naturais submarinos, associados à ocorrência de deslizamentos, e na indústria de exploração petrolífera, como potenciais reservatórios e selantes. Um extenso Sistema Deposicional Contornítico (CDS, Contourite Depositional System) formou-se no Golfo de Cádis, desde o fim do Miocénico Superior (5.33 Ma), pela ação da Água de Saída Mediterrânica (MOW, Mediterranean Outflow Water). Este CDS abrange vários depósitos contorníticos e outras formas sedimentares, deposicionais e erosivas, ao longo da margem continental Sul e Sudoeste Ibérica. O Contornito de Sines, localizado na margem Sudoeste Portuguesa, é um contornito distal do CDS do Golfo de Cádis. Este corpo situa-se entre 1000 e 2000 m de profundidade na Bacia do Alentejo, com aproximadamente 70 km de comprimento, 40 km de largura, 1 km de espessura, morfologia assimétrica e configuração agradante com inclinação para oeste. O Contornito de Sines está limitado por quatro morfoestruturas: a escarpa da Falha Pereira de Sousa com 1.4 km de altura a oeste, a plataforma continental a este e os canhões de Setúbal e São Vicente a norte e sul, respetivamente. Este trabalho apresenta uma análise sismostratigráfica e propõe um modelo evolutivo para o Contornito de Sines, além da identificação dos principais mecanismos e constrangimentos que controlaram a sua evolução. Para atingir estes objetivos, recorreu-se ao seguinte conjunto de dados: i) linhas de reflexão sísmica multicanal não publicadas, adquiridas durante a campanha MOWER/CONDRIBER em setembro-outubro de 2014; ii) linhas de reflexão sísmica multicanal, pré-existentes, dos projetos BIGSETS, STEAM e GSI; iii) batimetria multifeixe SWIM e iv) dados litostratigráficos e cronológicos da sondagem U1391 da Expedição 339 do IODP (Integrated Ocean Drilling Program), realizada em 2011-2012. A metodologia utilizada durante este trabalho consistiu em interpretação de estratigrafia sísmica, análise batimétrica, calibração e correlação cronostratigráfica dos horizontes e unidades sísmicas com a sondagem U1391 e representação gráfica das propriedades litológicas e físicas da sondagem referida. A interpretação sismostratigráfica dos dados apresentados permitiu identificar seis unidades sísmicas (U1 a U6), com idades compreendidas entre o Miocénico Superior e o Presente. Estas unidades foram depositadas sobre uma superfície basal erosiva (B) e estão separadas por cinco horizontes sísmicos (H2 a H6), que marcam descontinuidades na sucessão sísmica. As unidades sísmicas apresentam fácies transparente a maior profundidade, com configuração em cunha, que transita para uma fácies estratificada de elevada amplitude e configuração lobular a menor profundidade. A análise litostratigráfica da sondagem U1391 permitiu a calibração cronostratigráfica das unidades sísmicas interpretadas, bem como a caracterização da sua litologia. As unidades U2 (onde a sondagem U1391 atingiu a sua máxima profundidade) e U3, situadas entre os 671.5 e 566.1 m de profundidade, têm idades compreendidas entre o Pliocénico Superior e o Quaternário Inferior (3.2-2.5 Ma). Estas unidades são constituídas por vasa carbonatada, de composição dolomítica (~0.87 m) aos 632 m de profundidade e um debrito (~0.35 m) aos 604 m de profundidade. Às unidades U4 e U5, recuperadas entre 566.1 e 196.1 m de profundidade, foram atribuídas idades entre o Pleistocénico Inferior a Médio (2.5-0.7 Ma) e são constituídas por contornitos finos intercalados por sucessões de vasa carbonatada. A unidade sedimentar mais recente, U6, depositou-se desde o Pleistocénico Médio (0.7 Ma) até ao Presente. A unidade U6 é composta por alternância de depósitos contorníticos finos e grosseiros recuperados entre 196.1 m de profundidade e o fundo oceânico. Estes depósitos apresentam sucessões com bigradação, gradação normal e inversa (separadas por contactos gradacionais, bioturbados e, mais raramente, descontinuidades). Esta unidade contém seis intervalos contorníticos arenosos, areias finas a grosseiras, a 2, 50, 83, 96, 115 e 150 m de profundidade. Foram identificadas três fases na evolução deposicional do Contornito de Sines: 1) uma primeira fase de contornito com configuração em camada (sheeted drift) (<5.3-3.2 Ma), construída desde o final do Miocénico Superior, por uma corrente MOW de fraca intensidade; 2) uma fase de contornito monticular (mounded drift) (3.2-0.7 Ma), desde o Pliocénico Superior ao Quaternário Inferior, caracterizada por uma morfologia monticular a sul e agradante a norte, com uma sucessão de paleo-fossas sinuosas ao longo da margem continental a este, que atestam a ocorrência de uma intensificação moderada a elevada da MOW e 3) uma fase final de contornito agradante (plastered drift), desde o Pleistocénico Médio (0.7 Ma) até ao Presente, caracterizada pelas atuais formas deposicionais (contornitos argilosos a arenosos) e erosivas (fossas), associadas a dois eventos de intensificação da MOW. A formação do Contornito de Sines terá tido início no Miocénico Superior, possivelmente após o final da Crise de Salinidade do Messiniano, que afetou a região Mediterrânica entre 5.33 e 5.96 Ma, a qual teve repercussões drásticas para a circulação oceânica entre o Mediterrâneo e o Atlântico. Após a Crise de Salinidade do Messiniano e o restabelecimento da circulação através do Estreito de Gibraltar, a MOW possuía fraca intensidade. A sucessão de paleo-fossas subjacentes à fossa atual sugere uma corrente semipermanente e persistente ao longo da margem Sudoeste Portuguesa, em direção a norte, com vários eventos de intensificação. A edificação do Contornito de Sines foi constrangida pelas paleo-morfologias do fundo do mar que resultaram dos processos de rifting, herdados das fases de rifting Mesozóicas na margem Sudoeste Portuguesa. Estas paleo-morfologias forneceram espaço de acomodação para o crescimento do contornito e condicionaram a sua arquitetura deposicional. Os horsts e grabens, com orientação aproximada N-S, resultantes do rifting Mesozóico, confinaram a formação do contornito impedindo a sua migração lateral. A edificação do Contornito de Sines foi também influenciada por variações climáticas e eustáticas, especialmente durante a sua última fase de desenvolvimento. Durante o Quaternário, os eventos de intensificação da MOW correlacionam-se com dois eventos climáticos do Pleistocénico, registados na região Mediterrânica e nos depósitos contorníticos do Golfo de Cádis: o Middle Pleistocene Revolution (0.7-0.78 Ma) e o Late Quaternary Discontinuity (0.4 Ma). Os sedimentos que constituem o Contornito de Sines são maioritariamente sucessões contorníticas de composição carbonatada, com uma maior componente biogénica na primeira fase de desenvolvimento (sheeted drift), e uma maior componente siliciclástica (contornitos arenosos), na última fase de desenvolvimento (plastered drift). A componente biogénica na primeira fase provavelmente indica a ocorrência de fenómenos de afloramento costeiro e deposição hemipelágica ao longo da margem Oeste Portuguesa, enquanto que a maior contribuição siliciclástica na última fase está associada a eventos de intensificação da MOW. O Contornito de Sines evoluiu de um sistema deposicional inicialmente carbonatado para siliciclástico na última fase de desenvolvimento, testemunhando variações de intensidade da MOW. Os sedimentos carreados para a margem do Alentejo são maioritariamente fornecidos por deposição hemipelágica, fenómenos de afloramento costeiro e resultante de erosão da margem continental pela circulação da MOW. O Contornito de Sines não é significativamente afetado por processos gravíticos, sendo registado apenas uma ocorrência no Pliocénico (debrito de ~0.35 m). A baixa incidência de processos gravíticos resulta, provavelmente, da morfologia da margem e da existência dos canhões de Setúbal e São Vicente, que canalizam grande parte do material deslocado. No entanto, existem depósitos de movimento de massa que afetam o sector ocidental do Contornito de Sines, que estão associados ao elevado declive da escarpa da Falha Pereira de Sousa. A formação destes depósitos poderá estar associada a vários fatores intrínsecos e extrínsecos à área em estudo. No que se refere aos fatores intrínsecos, destaca-se a potencial geração de planos de descolamento nas interfaces entre sedimentos contorníticos arenosos e vasosos caso se encontrem sobre pressão, com excesso de fluídos e/ou intercalados por sedimentos menos porosos. No que respeita aos fatores extrínsecos, a atividade sísmica registada na margem Sudoeste Ibérica poderá espoletar a ocorrência de deslizamentos submarinos no Contornito de Sines. Os resultados obtidos sugerem que o Contornito de Sines teve uma evolução complexa, controlada por vários fatores, a diferentes escalas

    Pleistocene biostratigraphic markers of the North Pacific, IODP Site U1340: Proboscia barboi, Proboscia curvirostris and Thalassiosira jouseae

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    Diatoms are a large and widespread group of phytoplankton with an important role in ecosystems as primary producers. They are of great use in biostratigraphic and paleoclimatic studies, namely in the Bering Sea, where they are abundantly preserved in sediments. Proboscia barboi, Proboscia curvirostris and Thalassiosira jouseae are Plio-Pleistocene centric diatoms of mid to high latitudes of the North Pacific and North Atlantic Oceans, and are important biostratigraphic markers and datums in these regions. In this study, the biostratigraphy of these species at IODP Site U1340 (Bowers Ridge, Bering Sea) is refined and their abundance record interpreted in light of the paleoclimatic context of the North Pacific during the Plio-Pleistocene, using environmental information from the diatom assemblage in order to better understand the ecology of these extinct species. On a morphological approach, T. jouseae and its close related species Thalassiosira nidulus are described based on specimens of Site U1340 and their differences discussed. In addition, evidence for the evolutionary link between P. barboi and P. curvirostris is provided and discussed

    First molecular identification of mosquito vectors of Dirofilaria immitis in continental Portugal

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    BACKGROUND : Canine dirofilariasis due to Dirofilaria immitis is known to be endemic in continental Portugal. However, information about the transmitting mosquito species is still scarce, with only Culex theileri identified to date, albeit with L1-2, through dissection. This study was carried out to investigate the potential vectors of Dirofilaria spp. in continental Portugal. METHODS : Mosquitoes were collected in three distinct seasons (Summer, Autumn and Spring), 2011–2013, in three districts. CDC traps and indoor resting collections were carried out in the vicinity of kennels. Mosquitoes were kept under controlled conditions for 7 days to allow the development of larval stages of Dirofilaria spp.. DNA extraction was performed separately for both head+thorax and abdomen in order to differentiate infective and infected specimens, respectively, in pools, grouped according to the species and collection site (1–40 specimen parts/pool), and examined by PCR using pan-filarial specific primers. Mosquito densities were compared using non-parametric tests. Dirofilaria development units (DDU) were estimated. RESULTS : In total, 9156 female mosquitoes, from 11 different species, were captured. Mosquito densities varied among the 3 districts, according to capture method, and were generally higher in the second year of collections. From 5866 specimens screened by PCR, 23 head+thorax and 41 abdomens pools, corresponding to 54 mosquitoes were found positive for D. immitis DNA. These belonged to 5 species: Culex (Cux) theileri (estimated rate of infection (ERI)=0.71%), Cx. (Cux) pipiens f. pipiens and f. molestus (ERI=0.5%), Anopheles (Ano) maculipennis s.l. (ERI=3.12%), including An. (Ano) atroparvus, Aedes (Och) caspius (ERI=3.73%) and Ae. (Och) detritus s.l. (ERI=4.39%). All but Cx. pipiens, had at least one infective specimen. No D. repens infected specimens were found. Infection rates were: 3.21% in Coimbra, 1.22% in Setúbal and 0.54% in Santarém. DDU were at least 117/year in the study period. CONCLUSIONS : Culex theileri, Cx. pipiens, An. maculipennis s.l. An. atroparvus, Ae.caspius and Ae. detritus s.l. were identified as potential vectors of D. immitis in three districts of Portugal, from Spring to Autumn, in 5 of the 6 collection dates in 2011–2013. Implications for transmission, in the context of climate changes, and need for prophylactic measures, are discussed.Fundação para a Ciência e Tecnologia, project grant PTDC/SAU-SAP/113523/2009 and UPMM - PEst-OE/SAU/UI0074/2011-2014.http://www.parasitesandvectors.comam201
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