Browsing by Issue Date, starting with "2018-03"
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- Expectativas acadêmicas de estudantes nos primeiros anos do Ensino SuperiorPublication . Soares, Adriana Benevides; Romera Leme, Vanessa Barbosa; Gomes, Gil; Penha, Adriana Pecanha; Maia, Fatima Almeida; Lima, Claudio Almeida; Valadas, Sandra T.; Almeida, Leandro S.; Araujo, Alexandra M.This study analyzed students' expectations in the transition to Higher Education. Participants were 205 students of the first and second year, enrolled in public and private Higher Education institutions. Students answered an open questionnaire composed of five questions about personal expectations, interpersonal relationships, expectations about the undergraduate program and career development, the institution where they were enrolled, and a social-demographic questionnaire. Content analysis was performed to analyze data. Students described their own expectations regarding the job market, and personal and occupational benefits from studying in Higher Education. These results support previous studies that have suggested that first-year students present high expectations about higher education. We discuss the implications of the results in future researches and intervention with students, especially the ones with difficulties in academic adaptation.
- Effects of integration time on in-water radiometric profilesPublication . D'Alimonte, Davide; Zibordi, Giuseppe; Kajiyama, TamitoThis work investigates the effects of integration time on in-water downward irradiance E-d, upward irradiance E-u and upwelling radiance L-u profile data acquired with free-fall hyperspectral systems. Analyzed quantities are the subsurface value and the diffuse attenuation coefficient derived by applying linear and non-linear regression schemes. Case studies include oligotrophic waters (Case-1), as well as waters dominated by colored dissolved organic matter (CDOM) and non-algal particles (NAP). Assuming a 24-bit digitization, measurements resulting from the accumulation of photons over integration times varying between 8 and 2048ms are evaluated at depths corresponding to: 1) the beginning of each integration interval (FST); 2) the end of each integration interval (LST); 3) the averages of FST and LST values (AVG); and finally 4) the values weighted accounting for the diffuse attenuation coefficient of water (WGT). Statistical figures show that the effects of integration time can bias results well above 5% as a function of the depth definition. Results indicate the validity of the WGT depth definition and the fair applicability of the AVG one. Instead, both the FST and LST depths should not be adopted since they may introduce pronounced biases in E-u and L-u regression products for highly absorbing waters. Finally, the study reconfirms the relevance of combining multiple radiometric casts into a single profile to increase precision of regression products. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
- Strategies to mitigate shrinkage in self-compacting concretePublication . Oliveira, Miguel; Ribeiro, Antonio Bettencourt; Branco, Fernando GarridoO betão auto-compactável (BAC) apresenta propriedades especiais, que justificam a sua preferência em muitas aplicações. No entanto, são conhecidos vários casos de comportamento inadequado, devido principalmente ao comportamento deficiente deste material durante o processo de hidratação e secagem. A retração tem uma importância significativa na conceção, dimensionamento, processo construtivo e comportamento em serviço das estruturas de betão. As exigências normativas não consideram de forma adequada a influência dos fatores existentes. Além disso, a possibilidade de utilização de novos materiais limita fortemente a aplicação do conhecimento existente. De modo a contribuir para a resolução de uma das principais desvantagens deste material – a sua elevada retração, foi realizada uma campanha de ensaios, tendo em vista a avaliação dessa propriedade. Foi dada especial importância à utilização de adjuvantes redutores de retração e adições expansivas. Com base nos resultados obtidos foi possível avaliar a eficiência da utilização desses materiais. Obtiveram-se melhoramentos que permitiram formular uma hierarquização das estratégias de mitigação utilizadas.
- The interrelationships of land plants and the nature of the ancestral embryophytePublication . Puttick, Mark N.; Morris, Jennifer L.; Williams, Tom A.; Cox, C. J.; Edwards, Dianne; Kenrick, Paul; Pressel, Silvia; Wellman, Charles H.; Schneider, Harald; Pisani, Davide; Donoghue, Philip C. J.The evolutionary emergence of land plant body plans transformed the planet. However, our understanding of this formative episode is mired in the uncertainty associated with the phylogenetic relationships among bryophytes (hornworts, liverworts, and mosses) and tracheophytes (vascular plants). Here we attempt to clarify this problem by analyzing a large transcriptomic dataset with models that allow for compositional heterogeneity between sites. Zygnematophyceae is resolved as sister to land plants, but we obtain several distinct relationships between bryophytes and tracheophytes. Concate-nated sequence analyses that can explicitly accommodate site-specific compositional heterogeneity give more support for a mosses-liverworts clade, "Setaphyta,'' as the sister to all other land plants, and weak support for hornworts as the sister to all other land plants. Bryophyte monophyly is supported by gene concatenation analyses using models explicitly accommodating lineage-specific compositional heterogeneity and analyses of gene trees. Both maximum-likelihood analyses that compare the fit of each gene tree to proposed species trees and Bayesian supertree estimation based on gene trees support bryophyte monophyly. Of the 15 distinct rooted relationships for embryophytes, we reject all but three hypotheses, which differ only in the position of hornworts. Our results imply that the ancestral embryophyte was more complex than has been envisaged based on topologies recognizing liverworts as the sister lineage to all other embryophytes. This requires many phenotypic character losses and transformations in the liverwort lineage, diminishes inconsistency between phylogeny and the fossil record, and prompts re-evaluation of the phylogenetic affinity of early land plant fossils, the majority of which are considered stem tracheophytes.
- Over-elongation of centrioles in cancer promotes centriole amplification and chromosome missegregationPublication . Marteil, Gaelle; Guerrero, Adan; Vieira, Andre F.; de Almeida, Bernardo P.; Machado, Pedro; Mendonca, Susana; Mesquita, Marta; Villarreal, Beth; Fonseca, Irina; Francia, Maria E.; Dores, Katharina; Martins, Nuno P.; Jana, Swadhin C.; Tranfield, Erin M.; Barbosa-Morais, Nuno L.; Paredes, Joana; Pellman, David; Godinho, Susana A.; Bettencourt-Dias, MonicaCentrosomes are the major microtubule organising centres of animal cells. Deregulation in their number occurs in cancer and was shown to trigger tumorigenesis in mice. However, the incidence, consequence and origins of this abnormality are poorly understood. Here, we screened the NCI-60 panel of human cancer cell lines to systematically analyse centriole number and structure. Our screen shows that centriole amplification is widespread in cancer cell lines and highly prevalent in aggressive breast carcinomas. Moreover, we identify another recurrent feature of cancer cells: centriole size deregulation. Further experiments demonstrate that severe centriole over-elongation can promote amplification through both centriole fragmentation and ectopic procentriole formation. Furthermore, we show that overly long centrioles form over-active centrosomes that nucleate more microtubules, a known cause of invasiveness, and perturb chromosome segregation. Our screen establishes centriole amplification and size deregulation as recurrent features of cancer cells and identifies novel causes and consequences of those abnormalities.
- Skin and scale regeneration after mechanical damage in a teleostPublication . Costa, Rita; Power, DeborahSkin wound healing has been widely studied in mammalian models but the information on teleost cutaneous healing is sparse and frequently considered in the context of viral or bacterial infections or parasitic infestations in aquaculture. In the present study a detailed time course (0 h, 6 h, 1, 2, 3 and 4 days) coupled to morphology and gene expression analysis revealed rapid regeneration of skin without scarring in a marine teleost after a superficial wound caused by the loss of a large area of scales. The integrity of the integument, as assessed by quantification of extracellular matrix (ECM) gene transcripts (fn1a, colIα1, colVα2, colXα1, ogn1, ogn2, crtac1a, cyr61, pcna, krt2 and mmp9) was restored within 2 days. Epithelial-mesenchyme interactions assessed by expression of edar and shh were associated with epidermal closure, the re-establishment of the basement membrane and also scale eruption. Histological observations suggested tissue re-epithelialization was independent of inflammation and that transcripts representing the humoral and cellular elements of the immune response (mpo, cyba and csf1r, cd48 and cd200) were modulated in the early stages of sea bream (Sparus aurata) skin repair after injury. Overall, the results indicate that after superficial skin damage tissue reconstitution started immediately with re-epithelialization, followed by ECM deposition and finally tissue maturation, indicating that in the skin regenerative process, reconstitution of the physical barrier was the priority over other integument functions, including immune surveillance.
- Influência da aplicação de composto orgânico nas características do solo e no controlo biológico de nematodes em cenouraPublication . Coelho, Luísa; Reis, Mário; Bueno-Pallero, Francisco; Guerrero, Carlos; Gonçalves, MariaA aplicação de composto orgânico ao solo, para além das vantagens na fertilização já amplamente conhecidas, pode também ser uma solução para o controlo biológico de alguns inimigos das culturas. Este trabalho teve como objectivo estudar a influência da aplicação de um composto (Organical®), obtido a partir de lamas de ETAR, resíduos agrícolas, e de resíduos lenhosos como estruturante, nas propriedades químicas do solo e no controlo biológico de nematodes fitoparasitas, na cultura de cenoura, em solo ao ar livre, no período de outono – inverno.Num solo arenoso testaram-se 5 modalidades de fertilização: sem composto, e com incorporação do composto no solo entre 10 a 15 cm de profundidade, nas doses de 12,5; 25; 50 e 100 t.ha-1, em 3 blocos completos casualizados. Semeou-se cenoura (Daucus carota L.) ‘Nantes 5’, em linhas afastadas 20 cm. Após a emergência das plantas procedeu-se a um desbaste para obter a densidade de 6,25 plantas m-2. Quando as raízes maiores atingiram cerca de 15 cm, o que ocorreu 166 dias após a plantação, quantificou-se o crescimento e a produtividade das plantas e observaram-se as suas raízes para avaliar o nível de estrago causado por nematodes. Em cada bloco e modalidade, colheram-se amostras de solo, junto às raízes a cerca de 20 cm de profundidade, nas quais se determinou o teor de macro e micronutrientes, pH, condutividade eléctrica, matéria orgânica e metais pesados. Também se quantificaram e identificaram os nematodes presentes. No total, identificaram-se 25 géneros de nematodes, distribuídos por 3 grupos tróficos: bacteriofagos/saprofitas (BSN), fitofagos/fitotoparasitas (PPN) e predadores (PN). Verificou-se que o composto alterou a composição química do solo, aumentando significativamente a condutividade eléctrica, e o teor de potássio, fósforo e ferro, com o aumento da dose de composto. Observou-se que a diminuição dos estragos causados por nematodes estava directamente relacionada com a dose de incorporação de composto ao solo, tendo-se verificado também um aumento das populações dos nematodes BSN e PN com o aumento da dose de composto. Os resultados sugerem que a aplicação de composto ao solo poderá ser uma alternativa sustentável para controlar nematodes fitoparasitas na cultura da cenoura.
- Irreversible hypersomnolence after bilateral thalamic infarctionPublication . Mogildea, Mihail; Varela, Miguel; Martins, Cristiana; Joaquim, Natércia; Soleiro, Jose; Nzwalo, Hipolito
- Establishing microbial baselines to identify indicators of coral reef healthPublication . Glasl, Bettina; Bourne, David G.; Rodrigues Frade, Pedro; Webster, Nicole S.Microorganisms make a significant contribution to reef ecosystem health and resilience via their critical role in mediating nutrient transformations, their interactions with macro-organisms and their provision of chemical cues that underpin the recruitment of diverse reef taxa. However, environmental changes often cause compositional and functional shifts in microbial communities that can have flow-on consequences for microbial-mediated processes. These microbial alterations may impact the health of specific host organisms and can have repercussions for the functioning of entire coral ecosystems. Assessing changes in reef microbial communities should therefore provide an early indicator of ecosystem impacts and would underpin the development of diagnostic tools that could help forecast shifts in coral reef health under different environmental states. Monitoring, management and active restoration efforts have recently intensified and diversified in response to global declines in coral reef health. Here we propose that regular monitoring of coral reef microorganisms could provide a rapid and sensitive platform for identifying declining ecosystem health that can complement existing management frameworks. By summarising the most common threats to coral reefs, with a particular focus on the Great Barrier Reef, and elaborating on the role of microbes in coral reef health and ecosystem stability, we highlight the diagnostic applicability of microbes in reef management programs. Fundamental to this objective is the establishment of microbial baselines for Australia's coral reefs.
- Acidification increases abundances of Vibrionales and Planctomycetia associated to a seaweed-grazer system: potential consequences for disease and prey digestion efficiencyPublication . Aires, Tânia; Serebryakova, Alexandra; Viard, Frederique; Serrao, Ester A.; Engelen, Aschwin H.Ocean acidification significantly affects marine organisms in several ways, with complex interactions. Seaweeds might benefit from rising CO2 through increased photosynthesis and carbon acquisition, with subsequent higher growth rates. However, changes in seaweed chemistry due to increased CO2 may change the nutritional quality of tissue for grazers. In addition, organisms live in close association with a diverse microbiota, which can also be influenced by environmental changes, with feedback effects. As gut microbiomes are often linked to diet, changes in seaweed characteristics and associated microbiome can affect the gut microbiome of the grazer, with possible fitness consequences. In this study, we experimentally investigated the effects of acidification on the microbiome of the invasive brown seaweed Sargassum muticum and a native isopod consumer Synisoma nadejda. Both were exposed to ambient CO2 conditions (380 ppm, pH 8.16) and an acidification treatment (1,000 ppm, pH 7.86) for three weeks. Microbiome diversity and composition were determined using high-throughput sequencing of the variable regions V5-7 of 16S rRNA. We anticipated that as a result of acidification, the seaweed-associated bacterial community would change, leading to further changes in the gut microbiome of grazers. However, no significant effects of elevated CO2 on the overall bacterial community structure and composition were revealed in the seaweed. In contrast, significant changes were observed in the bacterial community of the grazer gut. Although the bacterial community of S. muticum as whole did not change, Oceanospirillales and Vibrionales (mainly Pseudoalteromonas) significantly increased their abundance in acidified conditions. The former, which uses organic matter compounds as its main source, may have opportunistically taken advantage of the possible increase of the C/N ratio in the seaweed under acidified conditions. Pseudoalteromonas, commonly associated to diseased seaweeds, suggesting that acidification may facilitate opportunistic/pathogenic bacteria. In the gut of S. nadejda, the bacterial genus Planctomycetia increased abundance under elevated CO2. This shift might be associated to changes in food (S. muticum) quality under acidification. Planctomycetia are slow-acting decomposers of algal polymers that could be providing the isopod with an elevated algal digestion and availability of inorganic compounds to compensate the shifted C/N ratio under acidification in their food. In conclusion, our results indicate that even after only three weeks of acidified conditions, bacterial communities associated to ungrazed seaweed and to an isopod grazer show specific, differential shifts in associated bacterial community. These have potential consequences for seaweed health (as shown in corals) and isopod food digestion. The observed changes in the gut microbiome of the grazer seem to reflect changes in the seaweed chemistry rather than its microbial composition.