198 research outputs found

    Geochemical characterization of the hydrous pyrolysis products from a recent cyanobacteria-dominated microbial mat

    Get PDF
    Hydrous pyrolysis experiments were performed on a recent microbial mat sample from Lagoa Vermelha, Brazil, to determine whether crude oil can be generated and expelled during artificial maturation of the Organic Matter (OM). The experiments were conducted at 280ºC, 330ºC and 350ºC during 20h. Two types of liquid pyrolysis products, assigned as free oil and bitumen, were isolated and analyzed. Free oil represents free organic phase released by hydrous pyrolysis, whereas bitumen was obtained by extraction from the solid pyrolysis residue with dichloromethane. Changes in the OM maturity were determined using Rock-Eval parameters and biomarker maturity ratios of original sample and pyrolysis products. Biomarker compositions of original sample extract and liquid pyrolysates were used for determination of dominant bacterial source. The yields of free oil and bitumen showed that a microbial mat OM has a high liquid hydrocarbons generation potential. Rock-Eval maturity parameters, biopolymer and biomarker compositions indicate a significant increase of the OM maturity during hydrous pyrolysis. At 280ºC the release of free, adsorbed and occluded compounds was observed; however, without a cracking of the OM. At 330ºC the generation of bitumen and free oil is mostly related to the OM cracking. The highest yield of free oil was recorded at this temperature. Distribution of biomarkers in the extract of original sample and liquid pyrolysates confirms cyanobacteria-dominated microbial mats, whereas the identification of long chain n-alkane series, with max

    One step forward towards the development of eco-friendly antifouling coatings: Immobilization of a sulfated marine-inspired compound

    Get PDF
    Marine biofouling represents a global economic and ecological challenge and few eco-friendly antifouling agents are available. The aim of this work was to establish the proof of concept that a recently synthesized nature-inspired compound (gallic acid persulfate, GAP) can act as an eco-friendly and effective antifoulant when immobilized in coatings through a non-release strategy, promoting a long-lasting antifouling effect. The synthesis of GAP was optimized to provide quantitative yields. GAP water solubility was assessed, showing values higher than 1000 mg/mL. GAP was found to be stable in sterilized natural seawater with a half-life (DT50) of 7 months. GAP was immobilized into several commercial coatings, exhibiting high compatibility with different polymeric matrices. Leaching assays of polydimethylsiloxane and polyurethane-based marine coatings containing GAP confirmed that the chemical immobilization of GAP was successful, since releases up to fivefold lower than the conventional releasing systems of polyurethane-based marine coatings were observed. Furthermore, coatings containing immobilized GAP exhibited the most auspicious anti-settlement effect against Mytilus galloprovincialis larvae for the maximum exposure period (40 h) in laboratory trials. Overall, GAP promises to be an agent capable of improving the antifouling activity of several commercial marine coatings with desirable environmental properties.This research was funded by national funds through the Foundation for Science and Technology (FCT) within the scope of research unit grants to CIIMAR (UIDB/04423/2020 and UIDP/04423/2020), to BioISI (UIDB/04046/2020 and UIDP/04046/2020) and under the project PTDC/AAG-TEC/0739/2014 (reference POCI-01-0145-FEDER-016793) supported through national funds provided by FCT and the European Regional Development Fund (ERDF) via the Programa Operacional Factores de Competitividade (POFC/COMPETE) programme and the Reforçar a Investigação, o Desenvolvimento Tecnológico e a Inovação (RIDTI; project 9471)

    Cyanobacterial diversity in microbial mats from the hypersaline lagoon system of Araruama, Brazil: An in-depth polyphasic study

    Get PDF
    Microbial mats are complex, micro-scale ecosystems that can be found in a wide range of environments. In the top layer of photosynthetic mats from hypersaline environments, a large diversity of cyanobacteria typically predominates. With the aim of strengthening the knowledge on the cyanobacterial diversity present in the coastal lagoon system of Araruama (state of Rio de Janeiro, Brazil), we have characterized three mat samples by means of a polyphasic approach. We have used morphological and molecular data obtained by culture-dependent and -independent methods. Moreover, we have compared different classification methodologies and discussed the outcomes, challenges, and pitfalls of these methods. Overall, we show that Araruama's lagoons harbor a high cyanobacterial diversity. Thirty-six unique morphospecies could be differentiated, which increases by more than 15% the number of morphospecies and genera already reported for the entire Araruama system. Morphology-based data were compared with the 16S rRNA gene phylogeny derived from isolate sequences and environmental sequences obtained by PCR-DGGE and pyrosequencing. Most of the 48 phylotypes could be associated with the observed morphospecies at the order level. More than one third of the sequences demonstrated to be closely affiliated (best BLAST hit results of ≥99%) with cyanobacteria from ecologically similar habitats. Some sequences had no close relatives in the public databases, including one from an isolate, being placed as "loner" sequences within different orders. This hints at hidden cyanobacterial diversity in the mats of the Araruama system, while reinforcing the relevance of using complementary approaches to study cyanobacterial diversity. © 2017 Ramos, Castelo-Branco, Leão, Martins, Carvalhal-Gomes, Sobrinho da Silva, Mendonça Filho and Vasconcelos.This work was supported by the Biogeochemical Project (AMPETRO 14777—Cooperation term 0050.0023165.06.4) of the GSE (Sedimentology Management) Network of PETROBRAS, by the Brazilian National Research Agency— CNPq and by the Research Agency of Rio de Janeiro State—FAPERJ. It was also funded by Portuguese National Funds through FCT—Fundação para a Ciência e a Tecnologia, grants SFRH/BD/80153/2011 to VR, IF/01358/2014 to PL, and UID/Multi/04423/2013 and by the Structured Program of R&D&I INNOVMAR—Innovation and Sustainability in the Management and Exploitation of Marine Resources (reference NORTE-01-0145-FEDER-000035, Research Line NOVELMAR), funded by the Northern Regional Operational Program (NORTE2020) through the European Regional Development Fund (ERDF)

    Geochemical characterization of the hydrous pyrolysis products from a recent cyanobacteria-dominated microbial mat.

    Get PDF
    Hydrous pyrolysis experiments were performed on a recent microbial mat sample from Lagoa Vermelha, Brazil, to determine whether crude oil can be generated and expelled during artificial maturation of the Organic Matter (OM). The experiments were conducted at 280 degrees C, 330 degrees C and 350 degrees C during 20h. Two types of liquid pyrolysis products, assigned as free oil and bitumen, were isolated and analyzed. Free oil represents free organic phase released by hydrous pyrolysis, whereas bitumen was obtained by extraction from the solid pyrolysis residue with dichloromethane. Changes in the OM maturity were determined using Rock-Eval parameters and biomarker maturity ratios of original sample and pyrolysis products. Biomarker compositions of original sample extract and liquid pyrolysates were used for deteiniination of dominant bacterial source. The yields of free oil and bitumen showed that a microbial mat OM has a high liquid hydrocarbons generation potential. Rock-Eval maturity parameters, biopolymer and biomarker compositions indicate a significant increase of the OM maturity during hydrous pyrolysis. At 280 degrees C the release of free, adsorbed and occluded compounds was observed; however, without a cracking of the OM. At 330 degrees C the generation of bitumen and free oil is mostly related to the OM cracking. The highest yield of free oil was recorded at this temperature. Distribution of biomarkers in the extract of original sample and liquid pyrolysates confirms cyanobacteria-dominated microbial mats, whereas the identification of long chain n-alkane series, with maximum at C-26, and prominent C-30 hop-17(21)-ene additionally suggest the presence of sulfate reducing bacteria

    Estimation of genetic parameters for milking temperament in Holstein-Gyr cows.

    Get PDF
    Introduction: Dairy cattle with poor temperament can cause several inconveniences during milking, leading to labor difficulties, increasing the risk of accidents with animals and workers, and compromising milk yield and quality. This study aimed to estimate variance components and genetic parameters for milking temperament and its genetic correlations with milk yield in crossbred Holstein-Gyr cattle. Methods: Data were collected at three commercial farms, resulting in 5,904 records from 1,212 primiparous and multiparous lactating cows. Milking temperament (MT), measured as the milking temperament of each cow, was assessed during pre-milking udder preparation (RP) and when fitting the milking cluster (RF) by ascribing scores from 1 (cow stands quietly) to 8 (the cow is very agitated, with vigorous movements and frequent kicking). The number of steps and kicks were also recorded during pre-milking udder preparation (SRP and KRP, respectively) and when fitting the milking cluster (SRF and KRF, respectively). Milk yield (MY) was obtained from each farm database. In two of them, MY was recorded during the monthly milk control (that could or could not coincide with the date when the milking temperament assessments were carried out) and in the remaining farm, MY was recorded on the same day that the milking temperament assessments were made. Genetic parameters were estimated using the THRGibbs1f90 program applying a threshold model, which included 89 contemporary groups as fixed effects, animal age at the assessment day and the number of days in milking as covariates, and direct additive genetic and residual effects as random effects. Results and discussions: The heritability estimates were MT= 0.14 ± 0.03 (for both, MRP and MRF), MY= 0.11 ± 0.08, SRP= 0.05 ± 0.03, KRP= 0.14 ± 0.05, SRF= 0.10 ± 0.05, and KRF= 0.32 ± 0.16. The repeatability estimates were 0.38 ± 0.05, 0.42 ± 0.02, and 0.84 ± 0.006 for MTRP, MTRF, and MY, respectively; and 0.38 ± 0.02, 0.30 ± 0.07, 0.52 ± 0.02, and 0.46 ± 0.15 for SRP, KRP, SRF, and KRF, respectively. The estimates of most genetic correlation coefficients between MTRP-MTRF were all strong and positive (MTRR-MTRF= 0.63 ± 0.10, MTRP-SRP= 0.65 ± 0.12, MTRP-KRP= 0.56 ± 0.16, MTRF-SRF= 0.77 ± 0.06, and MTRF-KRF= 0.56 ± 0.34) except for MY (MTRP-MY= 0.26 ± 0.26 and MTRF-MY= 0.21 ± 0.23). Despite the low magnitude of MT heritability, it can be included as a selection trait in the breeding program of Holsteins-Gyr cattle, although its genetic progress will be seen only in the long term. Due to the low accuracy of the genetic correlation estimates between MT and MY and the high range of the 95% posterior density interval, it cannot be affirmed by this study that the selection of a milking temperament trait will infer on milk yield. More data is therefore needed per cow and more cows need to be observed and measured to increase the reliability of the estimation of these correlations to be able to accurately interpret the results

    Sucesso e desenvolvimento psicológico no Ensino Superior: Estratégias de intervenção

    Get PDF
    O insucesso escolar destaca-se, actualmente, como uma das grandes preocupações em todas as reflexões sobre o Ensino Superior, situação que tem conduzido ao desenvolvimento de estratégias para intervir ao nível do combate a este fenómeno. O presente trabalho tem como objectivo apresentar um programa de intervenção interdisciplinar ao nível da promoção do sucesso académico, aliando apoio psicológico, suporte social e promoção de estilos de vida saudável, concretizado no desenvolvimento do modelo do GAP-SASUC. Tendo por base as quatro áreas de intervenção que suportam o modelo (Consultas de Psicologia, Apoio de Alunos por Alunos, Serviço Social e Investigação), são apresentados os resultados referentes à identificação das necessidades e problemas dos estudantes do Ensino Superior, às estratégias de intervenção utilizadas e à avaliação das mesmas. Os resultados, quer em termos do aumento de participação, quer em termos de avaliação positiva realizada pelos alunos envolvidos, revelam a mais-valia que este modelo de interacção trouxe ao desenvolvimento psicológico do estudante universitário. São, ainda, referidas algumas implicações do desenvolvimento e aplicação do modelo, com incidência para o bem-estar do aluno e promoção do sucesso no Ensino Superior
    corecore