188 research outputs found

    Tamanho de amostra para avaliação de caracteres de cenoura em sistemas de cultivo agroecológico.

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    O correto dimensionamento de experimentos deve ser utilizado para que se possa reduzir o erro experimental e com isso, maximizar a precisão das informações obtidas. O objetivo deste trabalho foi estimar o número mínimo de famílias e de plantas por parcela para avaliação de caracteres de raiz em uma população de cenoura cultivada em sistema agroecológico. Os ensaios foram conduzidos no verão de 2006/2007 em duas propriedades com cultivo agroecológico em Brasília: Associação Mokiti Okada, que segue modelo de Agricultura Natural em Brazlândia-DF e Núcleo Rural Taguatinga, seguindo modelo de Agricultura Orgânica em Taguatinga-DF. Foram avaliadas 100 famílias de meio-irmãos de cenoura dispostas em delineamento de blocos casualizados com duas repetições e parcelas de 1 m2. Foram colhidas 20 plantas competitivas por parcela e avaliadas individualmente para os caracteres comprimento de raiz, diâmetro da raiz, massa da raiz, diâmetro do xilema da raiz, relação diâmetro do xilema/diâmetro da raiz, tipo de ponta da raiz, tipo de ombro da raiz, parâmetro a* para os tecidos xilema e floema. Foi realizada análise de variância conjunta e para cada sistema, com informação entre e dentro de parcelas. Foram realizadas ainda análises de representatividade do número mínimo de famílias e de plantas para representar uma população de cenoura. Foi verificado que uma amostra de 18 plantas competitivas/parcela coletadas em ensaios com 2 repetições, bem como de 74 famílias, são suficientes para garantir uma adequada avaliação de famílias meio-irmãos de cenoura para os caracteres estudados

    A Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

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    Document submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresDocument submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresDocument submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresHyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of CPCP asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this document, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis has been updated from the previous Letter of Intent [K. Abe et al., arXiv:1109.3262 [hep-ex]], based on the experience gained from the ongoing T2K experiment. With a total exposure of 7.5 MW ×\times 107^7 sec integrated proton beam power (corresponding to 1.56×10221.56\times10^{22} protons on target with a 30 GeV proton beam) to a 2.52.5-degree off-axis neutrino beam produced by the J-PARC proton synchrotron, it is expected that the CPCP phase δCP\delta_{CP} can be determined to better than 19 degrees for all possible values of δCP\delta_{CP}, and CPCP violation can be established with a statistical significance of more than 3σ3\,\sigma (5σ5\,\sigma) for 7676% (5858%) of the δCP\delta_{CP} parameter space

    Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 x 10(20) protons on target

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    111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee commentsWe thank the J-PARC staff for superb accelerator performance and the CERN NA61/SHINE Collaboration for providing valuable particle production data. We acknowledge the support of MEXT, Japan; NSERC, NRC, and CFI, Canada; CEA and CNRS/IN2P3, France; DFG, Germany; INFN, Italy; National Science Centre (NCN), Poland; RSF, RFBR and MES, Russia; MINECO and ERDF funds, Spain; SNSF and SER, Switzerland; STFC, UK; and the U. S. Deparment of Energy, USA. We also thank CERN for the UA1/NOMAD magnet, DESY for the HERA-B magnet mover system, NII for SINET4, the WestGrid and SciNet consortia in Compute Canada, GridPP, UK, and the Emerald High Performance Computing facility in the Centre for Innovation, UK. In addition, participation of individual researchers and institutions has been further supported by funds from ERC (FP7), EU; JSPS, Japan; Royal Society, UK; and DOE Early Career program, USA

    Measurement of the electron neutrino charged-current interaction rate on water with the T2K ND280 pi(0) detector

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    10 pages, 6 figures, Submitted to PRDhttp://journals.aps.org/prd/abstract/10.1103/PhysRevD.91.112010© 2015 American Physical Society11 pages, 6 figures, as accepted to PRD11 pages, 6 figures, as accepted to PRD11 pages, 6 figures, as accepted to PR

    Animal welfare in studies on murine tuberculosis : assessing progress over a 12-year period and the need for further improvement

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    There is growing concern over the welfare of animals used in research, in particular when these animals develop pathology. The present study aims to identify the main sources of animal distress and to assess the possible implementation of refinement measures in experimental infection research, using mouse models of tuberculosis (TB) as a case study. This choice is based on the historical relevance of mouse studies in understanding the disease and the present and long-standing impact of TB on a global scale. Literature published between 1997 and 2009 was analysed, focusing on the welfare impact on the animals used and the implementation of refinement measures to reduce this impact. In this 12-year period, we observed a rise in reports of ethical approval of experiments. The proportion of studies classified into the most severe category did however not change significantly over the studied period. Information on important research parameters, such as method for euthanasia or sex of the animals, were absent in a substantial number of papers. Overall, this study shows that progress has been made in the application of humane endpoints in TB research, but that a considerable potential for improvement remains.Nuno H. Franco is funded by Fundação para a Ciência e Tecnologia (SFRH/BD/38337/2007). This work is funded by FEDER funds through the Operational Competitiveness Programme - COMPETE and by national funds through FCT - Fundação para a Ciência e Tecnologia under the project FCOMP-01-0124-FEDER-022718 (PEst-C/SAU/LA0002/2011

    Human milk and mucosal lacto- and galacto-N-biose synthesis by transgalactosylation and their prebiotic potential in Lactobacillus species

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    Lacto-N-biose (LNB) and galacto-N-biose (GNB) are major building blocks of free oligosaccharides and glycan moieties of glyco-complexes present in human milk and gastrointestinal mucosa. We have previously characterized the phospho-β-galactosidase GnbG from Lactobacillus casei BL23 that is involved in the metabolism of LNB and GNB. GnbG has been used here in transglycosylation reactions, and it showed the production of LNB and GNB with N-acetylglucosamine and N-acetylgalactosamine as acceptors, respectively. The reaction kinetics demonstrated that GnbG can convert 69 ± 4 and 71 ± 1 % of o-nitrophenyl-β-D-galactopyranoside into LNB and GNB, respectively. Those reactions were performed in a semi-preparative scale, and the synthesized disaccharides were purified. The maximum yield obtained for LNB was 10.7 ± 0.2 g/l and for GNB was 10.8 ± 0.3 g/l. NMR spectroscopy confirmed the molecular structures of both carbohydrates and the absence of reaction byproducts, which also supports that GnbG is specific for β1,3-glycosidic linkages. The purified sugars were subsequently tested for their potential prebiotic properties using Lactobacillus species. The results showed that LNB and GNB were fermented by the tested strains of L. casei, Lactobacillus rhamnosus (except L. rhamnosus strain ATCC 53103), Lactobacillus zeae, Lactobacillus gasseri, and Lactobacillus johnsonii. DNA hybridization experiments suggested that the metabolism of those disaccharides in 9 out of 10 L. casei strains, all L. rhamnosus strains and all L. zeae strains tested relies upon a phospho-β-galactosidase homologous to GnbG. The results presented here support the putative role of human milk oligosaccharides for selective enrichment of beneficial intestinal microbiota in breast-fed infants

    Genome-Wide Identification, Characterization and Phylogenetic Analysis of the Rice LRR-Kinases

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    LRR-kinases constitute the largest subfamily of receptor-like kinases in plants and regulate a wide variety of processes related to development and defense. Through a reiterative process of sequence analysis and re-annotation, we identified 309 LRR-kinase genes in the rice genome (Nipponbare). Among them, 127 genes in the Rice Annotation Project Database and 85 in Refseq of NCBI were amended (in addition, 62 LRR-kinase genes were not annotated in Refseq). The complete set of LRR-kinases was characterized. These LRR-kinases were classified into five groups according to phylogenetic analysis, and the genes in groups 1, 2, 3 and 4 usually have fewer introns than those in group 5. The introns in the LRR domain, which are highly conserved in regards to their positions and configurations, split the first Leu or other amino residues at this position of the ‘xxLxLxx’ motif with phase 2 and usually separate one or more LRR repeats exactly. Tandemly repeated LRR motifs have evolved from exon duplication, mutation and exon shuffling. The extensive distribution and diversity of the LRR-kinase genes have been mainly generated by tandem duplication and mutation after whole genome duplication. Positive selection has made a limited contribution to the sequence diversity after duplication, but positively selected sites located in the LRR domain are thought to involve in the protein-protein interaction

    Organization and molecular evolution of a disease-resistance gene cluster in coffee trees

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    <p>Abstract</p> <p>Background</p> <p>Most disease-resistance (R) genes in plants encode NBS-LRR proteins and belong to one of the largest and most variable gene families among plant genomes. However, the specific evolutionary routes of NBS-LRR encoding genes remain elusive. Recently in coffee tree (<it>Coffea arabica</it>), a region spanning the <it>S</it><sub><it>H</it></sub><it>3 </it>locus that confers resistance to coffee leaf rust, one of the most serious coffee diseases, was identified and characterized. Using comparative sequence analysis, the purpose of the present study was to gain insight into the genomic organization and evolution of the <it>S</it><sub><it>H</it></sub><it>3 </it>locus.</p> <p>Results</p> <p>Sequence analysis of the <it>S</it><sub><it>H</it></sub><it>3 </it>region in three coffee genomes, E<sup>a </sup>and C<sup>a </sup>subgenomes from the allotetraploid <it>C. arabica </it>and C<sup>c </sup>genome from the diploid <it>C. canephora</it>, revealed the presence of 5, 3 and 4 R genes in E<sup>a</sup>, C<sup>a</sup>, and C<sup>c </sup>genomes, respectively. All these R-gene sequences appeared to be members of a CC-NBS-LRR (CNL) gene family that was only found at the <it>S</it><sub><it>H</it></sub><it>3 </it>locus in <it>C. arabica</it>. Furthermore, while homologs were found in several dicot species, comparative genomic analysis failed to find any CNL R-gene in the orthologous regions of other eudicot species. The orthology relationship among the <it>S</it><sub><it>H</it></sub><it>3</it>-CNL copies in the three analyzed genomes was determined and the duplication/deletion events that shaped the <it>S</it><sub><it>H</it></sub><it>3 </it>locus were traced back. Gene conversion events were detected between paralogs in all three genomes and also between the two sub-genomes of <it>C. arabica</it>. Significant positive selection was detected in the solvent-exposed residues of the <it>S</it><sub><it>H</it></sub><it>3</it>-CNL copies.</p> <p>Conclusion</p> <p>The ancestral <it>S</it><sub><it>H</it></sub><it>3</it>-CNL copy was inserted in the <it>S</it><sub><it>H</it></sub><it>3 </it>locus after the divergence between Solanales and Rubiales lineages. Moreover, the origin of most of the <it>S</it><sub><it>H</it></sub><it>3</it>-CNL copies predates the divergence between <it>Coffea </it>species. The <it>S</it><sub><it>H</it></sub><it>3</it>-CNL family appeared to evolve following the birth-and-death model, since duplications and deletions were inferred in the evolution of the <it>S</it><sub><it>H</it></sub><it>3 </it>locus. Gene conversion between paralog members, inter-subgenome sequence exchanges and positive selection appear to be the major forces acting on the evolution of <it>S</it><sub><it>H</it></sub><it>3</it>-CNL in coffee trees.</p

    Hunger Artists: Yeast Adapted to Carbon Limitation Show Trade-Offs under Carbon Sufficiency

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    As organisms adaptively evolve to a new environment, selection results in the improvement of certain traits, bringing about an increase in fitness. Trade-offs may result from this process if function in other traits is reduced in alternative environments either by the adaptive mutations themselves or by the accumulation of neutral mutations elsewhere in the genome. Though the cost of adaptation has long been a fundamental premise in evolutionary biology, the existence of and molecular basis for trade-offs in alternative environments are not well-established. Here, we show that yeast evolved under aerobic glucose limitation show surprisingly few trade-offs when cultured in other carbon-limited environments, under either aerobic or anaerobic conditions. However, while adaptive clones consistently outperform their common ancestor under carbon limiting conditions, in some cases they perform less well than their ancestor in aerobic, carbon-rich environments, indicating that trade-offs can appear when resources are non-limiting. To more deeply understand how adaptation to one condition affects performance in others, we determined steady-state transcript abundance of adaptive clones grown under diverse conditions and performed whole-genome sequencing to identify mutations that distinguish them from one another and from their common ancestor. We identified mutations in genes involved in glucose sensing, signaling, and transport, which, when considered in the context of the expression data, help explain their adaptation to carbon poor environments. However, different sets of mutations in each independently evolved clone indicate that multiple mutational paths lead to the adaptive phenotype. We conclude that yeasts that evolve high fitness under one resource-limiting condition also become more fit under other resource-limiting conditions, but may pay a fitness cost when those same resources are abundant
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