410 research outputs found

    Probing Local Variations of Superconductivity on the Surface of Ba(Fe1-xCox)2As2 Single Crystals

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    The spatially resolved electrical transport properties have been studied on the surface of optimally-doped superconducting Ba(Fe1-xCox)2As2 single crystal by using a four-probe scanning tunneling microscopy. While some non-uniform contrast appears near the edge of the cleaved crystal, the scanning electron microscopy (SEM) reveals mostly uniform contrast. For the regions that showed uniform SEM contrast, a sharp superconducting transition at TC = 22.1 K has been observed with a transition width (delta)Tc = 0.2 K. In the non-uniform contrast region, TC is found to vary between 19.6 and 22.2 K with (delta)Tc from 0.3 to 3.2 K. The wavelength dispersive x-ray spectroscopy reveals that Co concentration remains 7.72% in the uniform region, but changes between 7.38% and 7.62% in the non-uniform region. Thus the variations of superconductivity are associated with local compositional change.Comment: 18 pages, 5 figure

    Shark-dust: Application of high-throughput DNA sequencing of processing residues for trade monitoring of threatened sharks and rays

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    Illegal fishing, unregulated bycatch, and market demand for certain products (e.g., fins) are largely responsible for the rapid global decline of shark and ray populations. Controlling trade of endangered species remains difficult due to product variety, taxonomic ambiguity, and trade complexity. The genetic tools traditionally used to identify traded species typically target individual tissue samples, and are time-consuming and/or species-specific. Here, we performed high-throughput sequencing of trace DNA fragments retrieved from dust and scraps left behind by trade activities. We metabarcoded “shark-dust” samples from seven processing plants in the world's biggest shark landing site (Java, Indonesia), and identified 61 shark and ray taxa (representing half of all chondrichthyan orders), more than half of which could not be recovered from tissue samples collected in parallel from the same sites. Importantly, over 80% of shark-dust sequences were found to belong to CITES-listed species. We argue that this approach is likely to become a powerful and cost-effective monitoring tool wherever wildlife is traded

    Shark-dust: high-throughput DNA sequencing of processing residues unveils widespread trade in threatened sharks and rays

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    Illegal fishing, unregulated bycatch, and market demand for certain products (e.g. fins) are largely responsible for the rapid global decline of shark and ray populations. Controlling trade of endangered species remains difficult due to product variety, taxonomic ambiguity and trade complexity. The genetic tools traditionally used to identify traded species typically target individual tissue samples, are time-consuming and/or species-specific. Here, we performed high-throughput sequencing of trace DNA fragments retrieved from dust and scraps left behind by trade activities. We metabarcoded ‘shark-dust’ samples from seven processing plants in the world’s biggest shark landing site (Java, Indonesia), and identified 54 shark and ray taxa (representing half of all chondrichthyan orders), half of which could not be recovered from tissue samples collected in parallel from the same sites. Importantly, over 80% of shark-dust sequences were found to belong to CITES-listed species. We argue that this approach is likely to become a powerful and cost-effective monitoring tool wherever wildlife is traded

    Efeito do reposicionamento otolítico e da reabilitação vestibular no zumbido: Uma revisão de literatura / Effect of otolytic repositioning and vestibular rehabilitation on tinnitus: A literature review

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    O zumbido é a percepção de um estímulo sonoro sem que tenha uma fonte geradora no meio ambiente. Pacientes vertiginosos podem também apresentar o zumbido como sintoma otoneurológico. Nos casos diagnosticados como Vertigem Posicional Paroxística Benigna (VPPB) o tratamento é denominado de reposicionamento otolítico e para tonturas crônicas a intervenção é intitulada reabilitação vestibular. Em ambos os quadros, pode existir sintomatologia associada de tontura com zumbido, pois uma alteração no sistema vestibular pode desencadear quaisquer outros sintomas otoneurológicos. Vertigem e zumbido podem acarretar problemas como ansiedade, irritabilidade e desequilíbrio emocional. Frente essa problemática, o presente estudo objetivou verificar a percepção do zumbido pelo paciente que realiza o reposicionamento otolítico e/ou reabilitação vestibular, antes e após o tratamento por meio de revisão da literatura. Assim, foi realizado um levantamento bibliográfico com auxílio dos bancos de dados SciELO, Lilacs, BVS, MedLine, Bireme, CAPES e Google Acadêmico, utilizando palavras-chave e descritores específicos na busca de estudos pertinentes à questão proposta. Sendo ela limitada a artigos publicados entre janeiro de 2010 a dezembro de 2020 e selecionados materiais nos idiomas português, inglês e espanhol. Após os critérios de exclusão dos artigos científicos, foi realizado uma correlação daqueles selecionados. O estudo mostrou que ambos, reposicionamento otolítico e reabilitação vestibular, diminuem a percepção do zumbido pelo indivíduo afetado. Apesar dos resultados positivos quanto a eficácia dos tratamentos abordados, percebeu-se a necessidade de aprofundamento em conhecimentos científicos, visto que nos últimos anos a literatura foi sutil em abordar o tema, que é de importância para a qualidade de vida.

    The higher exercise intensity and the presence of allele I of ACE gene elicit a higher post-exercise blood pressure reduction and nitric oxide release in elderly women: an experimental study

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    <p>Abstract</p> <p>Background</p> <p>The absence of the I allele of the angiotensin converting enzyme (ACE) gene has been associated with higher levels of circulating ACE, lower nitric oxide (NO) release and hypertension. The purposes of this study were to analyze the post-exercise salivary nitrite (NO<sub>2</sub><sup>-</sup>) and blood pressure (BP) responses to different exercise intensities in elderly women divided according to their ACE genotype.</p> <p>Methods</p> <p>Participants (n = 30; II/ID = 20 and DD = 10) underwent three experimental sessions: incremental test - IT (15 watts workload increase/3 min) until exhaustion; 20 min exercise 90% anaerobic threshold (90% AT); and 20 min control session without exercise. Volunteers had their BP and NO<sub>2</sub><sup>- </sup>measured before and after experimental sessions.</p> <p>Results</p> <p>Despite both intensities showed protective effect on preventing the increase of BP during post-exercise recovery compared to control, post-exercise hypotension and increased NO<sub>2</sub><sup>- </sup>release was observed only for carriers of the I allele (p < 0.05).</p> <p>Conclusion</p> <p>Genotypes of the ACE gene may exert a role in post-exercise NO release and BP response.</p

    Primer biases in the molecular assessment of diet in multiple insectivorous mammals

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    Our understanding of trophic interactions of small insectivorous mammals has been drastically improved with the advent of DNA metabarcoding. The technique has continued to be optimised over the years, with primer choice repeatedly being a vital factor for dietary inferences. However, the majority of dietary studies examining the effect of primer choice often rely on in silico analyses or comparing between species that occupy an identical niche type. Here, we apply DNA metabarcoding to empirically compare the prey detection capabilities of two widely used primer sets when assessing the diets of a flying (lesser horseshoe bat; Rhinolophus hipposideros) and two ground-dwelling insectivores (greater white-toothed shrew; Crocidura russula and pygmy shrew; Sorex minutus). Although R. hipposideros primarily rely on two prey orders (Lepidoptera and Diptera), the unique taxa detected by each primer shows that a combination of primers may be the best approach to fully describe bat trophic ecology. However, random forest classifier analysis suggests that one highly degenerate primer set detected the majority of both shrews’ diet despite higher levels of host amplification. The wide range of prey consumed by ground-dwelling insectivores can therefore be accurately documented from using a single broad-range primer set, which can decrease cost and labour. The results presented here show that dietary inferences will differ depending on the primer or primer combination used for insectivores occupying different niches (i.e., hunting in the air or ground) and demonstrate the importance of performing empirical pilot studies for novel study systems

    Core competencies in the science and practice of knowledge translation: description of a Canadian strategic training initiative

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    <p>Abstract</p> <p>Background</p> <p>Globally, healthcare systems are attempting to optimize quality of care. This challenge has resulted in the development of implementation science or knowledge translation (KT) and the resulting need to build capacity in both the science and practice of KT.</p> <p>Findings</p> <p>We are attempting to meet these challenges through the creation of a national training initiative in KT. We have identified core competencies in this field and have developed a series of educational courses and materials for three training streams. We report the outline for this approach and the progress to date.</p> <p>Conclusions</p> <p>We have prepared a strategy to develop, implement, and evaluate a national training initiative to build capacity in the science and practice of KT. Ultimately through this initiative, we hope to meet the capacity demand for KT researchers and practitioners in Canada that will lead to improved care and a strengthened healthcare system.</p

    The stellar halo of the Galaxy

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    Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most ubiquitous component of galaxies, independently of their Hubble type. This review focuses on our current understanding of the spatial structure, the kinematics and chemistry of halo stars in the Milky Way. In recent years, we have experienced a change in paradigm thanks to the discovery of large amounts of substructure, especially in the outer halo. I discuss the implications of the currently available observational constraints and fold them into several possible formation scenarios. Unraveling the formation of the Galactic halo will be possible in the near future through a combination of large wide field photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes. Full-resolution version available at http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd
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