183 research outputs found

    Adaptation and convergence in circadian‐related genes in Iberian freshwater fish

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    The circadian clock is a biological timing system that improves the ability of organisms to deal with environmental fluctuations. At the molecular level it consists of a network of transcription-translation feedback loops, involving genes that activate (bmal and clock - positive loop) and repress expression (cryptochrome (cry) and period (per) - negative loop). This is regulated by daily alternations of light but can also be affected by temperature. Fish, as ectothermic, depend on the environmental temperature and thus are good models to study its integration within the circadian system. Here, we studied the molecular evolution of circadian genes in four Squalius freshwater fish species, distributed across Western Iberian rivers affected by two climatic types with different environmental conditions (e.g., light and temperature). S. carolitertii and S. pyrenaicus inhabit the colder northern region under Atlantic climate type, while S. torgalensis, S. aradensis and some populations of S. pyrenaicus inhabit the warmer southern region affected by summer droughts, under Mediterranean climate type.info:eu-repo/semantics/publishedVersio

    BetĂ”es de elevado desempenho com nano-partĂ­culas de TiO2 e cinzas volantes : resistĂȘncia mecĂąnica, durabilidade e custo

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    Os betĂ”es de elevado desempenho apresentam vantagens vĂĄrias sobre os betĂ”es correntes nomeadamente elevada resistĂȘncia e durabilidade. Estes materiais permitem a execução de estruturas com menor quantidade de aço e com uma vida Ăștil superior, fatores cruciais para a eco-eficiĂȘncia daquelas. Apesar disso as publicaçÔes sobre betĂ”es com nano-partĂ­culas sĂŁo escassas, representando apenas 1% do total de publicaçÔes em revista internacional sobre estes materiais. As publicaçÔes sobre betĂ”es de elevado desempenho com nano-partĂ­culas sĂŁo ainda mais reduzidas. O presente artigo apresenta resultados de uma investigação experimental sobre a resistĂȘncia mecĂąnica e a durabilidade de betĂ”es de elevado desempenho contendo nano-partĂ­culas de TiO2 e cinzas volantes. Os parĂąmetros de durabilidade foram avaliados com recurso a ensaios de absorção de ĂĄgua por imersĂŁo e por capilaridade, ensaios de ultra-sons, resistividade elĂ©trica, difusĂŁo de cloretos e resistĂȘncia ao ataque quĂ­mico. Os resultados mostram que betĂ”es com um teor crescente de nano-partĂ­culas de TiO2 evidenciam uma redução da durabilidade. Mostram tambĂ©m que betĂ”es com 1% de nano-partĂ­culas de TiO2 e substituição parcial de cimento Portland por 30% de cinzas volantes apresentam uma elevada resistĂȘncia mecĂąnica (C55/C67) a par de uma elevada durabilidade. Contudo as nano-partĂ­culas de TiO2 agravam de forma muito significativa o custo dos betĂ”es

    Utilização de nano-partículas para a obtenção de betÔes de elevado desempenho

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    Os betĂ”es de elevado desempenho apresentam vantagens vĂĄrias sobre os betĂ”es correntes nomeadamente elevada resistĂȘncia e durabilidade. Estes materiais permitem a execução de estruturas com menor quantidade de aço e com uma vida Ăștil superior, fatores cruciais para a ecoeficiĂȘncia daquelas. Apesar disso as publicaçÔes sobre betĂ”es com nano-partĂ­culas sĂŁo escassas, representando apenas 1% do total de publicaçÔes sobre estes materiais. As publicaçÔes sobre betĂ”es de elevado desempenho com nano-partĂ­culas sĂŁo ainda mais reduzidas. O presente artigo apresenta resultados de uma investigação experimental sobre a resistĂȘncia mecĂąnica e a durabilidade de betĂ”es de elevado desempenho contendo nano-partĂ­culas de TiO2 e cinzas volantes. Os parĂąmetros de durabilidade foram avaliados com recurso a ensaios de absorção de ĂĄgua por imersĂŁo e por capilaridade, ensaio de ultra-sons, resistividade elĂ©trica, difusĂŁo de cloretos e resistĂȘncia ao ataque quĂ­mico. Os resultados mostram que betĂ”es com um teor crescente de nano-partĂ­culas de TiO2 evidenciam uma redução da durabilidade. Os resultados mostram tambĂ©m que betĂ”es com 1% nanopartĂ­culas de TiO2 e substituição parcial de cimento Portland por 30% de cinzas volantes apresentam uma elevada resistĂȘncia mecĂąnica (C55/C67) a par de uma elevada durabilidade. Os resultados permitiram ainda detetar vĂĄrias correlaçÔes estatisticamente significativas

    Numerical-experimental plastic-damage characterisation of additively manufactured 18ni300 maraging steel by means of multiaxial double-notched specimens

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    PTDC/EME/31307/2017Additive manufacturing (AM) has become a viable option for producing structural parts with a high degree of geometrical complexity. Despite such trend, accurate material properties, under diversified testing conditions, are scarce or practically non-existent for the most recent additively manufactured (AMed) materials. Such data gap may compromise component performance design, through numerical simulation, especially enhanced by topological optimisation of AMed components. This study aimed at a comprehensive characterisation of laser powder bed fusion as-built 18Ni300 maraging steel and its systematic comparison to the conventional counterpart. Multiaxial double-notched specimens demonstrated a successful depiction of both plastic and damage behaviour under different stress states. Tensile specimens with distinct notch configurations were also used for high stress triaxiality range characterisation. This study demonstrates that the multiaxial double-notched specimens constitute a viable option towards the inverse plastic behaviour calibration of high-strength additively manufactured steels in distinct state of stress conditions. AMed maraging steel exhibited higher strength and lower ductility than the conventional material.publishersversionpublishe

    The Personal Genome Project-UK, an open access resource of human multi-omics data

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    Integrative analysis of multi-omics data is a powerful approach for gaining functional insights into biological and medical processes. Conducting these multifaceted analyses on human samples is often complicated by the fact that the raw sequencing output is rarely available under open access. The Personal Genome Project UK (PGP-UK) is one of few resources that recruits its participants under open consent and makes the resulting multi-omics data freely and openly available. As part of this resource, we describe the PGP-UK multi-omics reference panel consisting of ten genomic, methylomic and transcriptomic data. Specifically, we outline the data processing, quality control and validation procedures which were implemented to ensure data integrity and exclude sample mix-ups. In addition, we provide a REST API to facilitate the download of the entire PGP-UK dataset. The data are also available from two cloud-based environments, providing platforms for free integrated analysis. In conclusion, the genotype-validated PGP-UK multi-omics human reference panel described here provides a valuable new open access resource for integrated analyses in support of personal and medical genomics

    An experimental investigation on nano-TiO2 and fly ash based high performance concrete

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    High performance concrete (HPC) offers several advantages over normal-strength concrete, namely, high mechanical strength and high durability. Therefore, HPC allows for concrete structures with less steel reinforcement and a longer service life, both of which are crucial issues in the eco-efficiency of construction materials. Nevertheless international publications on the field of concrete containing nanoparticles are scarce when compared to Portland cement concrete (around 1%) of the total international publications. HPC nanoparticle-based publications are even scarcer. This article presents the results of an experimental investigation on the mechanical properties and durability of HPC based on nano-TiO2 and fly ash. The durability performance was assessed by means of water absorption by immersion, water absorption by capillarity, ultrasonic pulse velocity, electric resistivity, chloride diffusion and resistance to sulphuric acid attack. The results show that the concretes containing an increased content of nano-TiO2 show decreased durability performance. The results also show that concrete with 1% nano-TiO2 and 30% fly ash as Portland cement replacement show a high mechanical strength (C55/C67) and a high durability. However, it should be noted that the cost of nano-TiO2 is responsible for a severe increase in the cost of concrete mixtures.(undefined

    Selection of endogenous genes for gene expression studies in Eucalyptus under biotic (Puccinia psidii) and abiotic (acibenzolar-S-methyl) stresses using RT-qPCR

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    <p>Abstract</p> <p>Background</p> <p>Rust caused by <it>Puccinia psidii </it>Winter has been limiting for the establishment of new <it>Eucalyptus </it>plantations, as well as for resprouting of susceptible genetic materials. Identifying host genes involved in defense responses is important to elucidate resistance mechanisms. Reverse transcription-quantitative PCR is the most common method of mRNA quantitation for gene expression analysis. This method generally employs a reference gene as an internal control to normalize results. A good endogenous control transcript shows minimal variation due to experimental conditions.</p> <p>Findings</p> <p>We analyzed the expression of 13 genes to identify transcripts with minimal variation in leaves of 60-day-old clonal seedlings of two <it>Eucalyptus </it>clones (rust-resistant and susceptible) subjected to biotic (<it>P. psidii</it>) and abiotic (acibenzolar-S-methyl, ASM) stresses.</p> <p>Conclusions</p> <p>For tissue samples of clones that did not receive any stimulus, a combination of the <it>eEF2 </it>and <it>EglDH </it>genes was the best control for normalization. When pathogen-inoculated and uninoculated plant samples were compared, <it>eEF2 </it>and <it>UBQ </it>together were more appropriate as normalizers. In ASM-treated and untreated leaves of both clones, transcripts of the <it>CYP </it>and <it>elF4B </it>genes combined were the ones with minimal variation. Finally, when comparing expression in both clones for ASM-treated leaves, <it>P. psidii</it>-inoculated leaves, ASM-treated plus <it>P. psidii</it>-inoculated leaves, and their respective controls, the genes with the most stable expression were <it>EgIDH </it>and <it>UBQ</it>. The chitinase gene, which is highly expressed in studies on plant resistance to phytopathogens, was used to confirm variation in gene expression due to the treatments.</p

    Comparative analysis between synthetic vitamin E and natural antioxidant sources from tomato, carrot and coriander in diets for market-sized dicentrarchus labrax

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    Synthetic vitamin E is commonly used in aquafeeds to prevent oxidative stress in fish and delay feed and flesh oxidation during storage, but consumers’ preferences tend towards natural antioxidant sources. The potential of vegetable antioxidants-rich coproducts, dried tomato (TO), carrot (CA) and coriander (CO) was compared to that of synthetic vitamin E included in diets at either a regular (CTRL; 100 mg kg−1) or reinforced dose (VITE; 500 mg kg−1). Natural antioxidants were added at 2% to the CTRL. Mixes were then extruded and dried, generating five experimental diets that were fed to European sea bass juveniles (114 g) over 12 weeks. Vitamin E and carotenoid content of extruded diets showed signs of degradation. The experimental diets had very limited effects on fish growth or body composition, immunomodulatory response, muscle and liver antioxidant potential, organoleptic properties or consumer acceptance. Altogether, experimental findings suggest that neither a heightened inclusion dose of 500 mg kg−1 of vitamin E, nor a 2% inclusion of natural antioxidants provided additional antioxidant protection, compared to fish fed diets including the regular dose of 100 mg kg−1 of vitamin E.info:eu-repo/semantics/publishedVersio

    Charge densities and charge noise in mesoscopic conductors

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    We introduce a hierarchy of density of states to characterize the charge distribution in a mesoscopic conductor. At the bottom of this hierarchy are the partial density of states which represent the contribution to the local density of states if both the incident and the out-going scattering channel is prescribed. The partial density of states play a prominent role in measurements with a scanning tunneling microscope on multiprobe conductors in the presence of current flow. The partial density of states determine the degree of dephasing generated by a weakly coupled voltage probe. In addition the partial density of states determine the frequency-dependent response of mesoscopic conductors in the presence of slowly oscillating voltages applied to the contacts of the sample. The partial density of states permit the formulation of a Friedel sum rule which can be applied locally. We introduce the off-diagonal elements of the partial density of states matrix to describe charge fluctuation processes. This generalization leads to a local Wigner-Smith life-time matrix.Comment: 10 pages, 2 figure
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