8,227 research outputs found

    Invariant manifolds and equilibrium states for non-uniformly hyperbolic horseshoes

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    In this paper we consider horseshoes containing an orbit of homoclinic tangency accumulated by periodic points. We prove a version of the Invariant Manifolds Theorem, construct finite Markov partitions and use them to prove the existence and uniqueness of equilibrium states associated to H\"older continuous potentials.Comment: 33 pages, 6 figure

    Canonical Analysis of the Jackiw-Teitelboim Model in the Temporal Gauge. I. The Classical Theory

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    As a preparation for its quantization in the loop formalism, the 2-dimensional gravitation model of Jackiw and Teitelboim is analysed in the classical canonical formalism. The dynamics is of pure constraints as it is well-known. A partial gauge fixing of the temporal type being performed, the resulting second class constraints are sorted out and the corresponding Dirac bracket algebra is worked out. Dirac observables of this classical theory are then calculated.Comment: 15 pages, Latex. Misprint correction

    Polygalacturonase gene FaPG1 downregulation is related to increased strawberry fruit resistance to fungal decay

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    Plant health is a major target in breading programs because crops are under constant biotic stress, and climate change is exacerbating pests and disease negative impacts in agriculture. Obtaining crop varieties armed with better defences is a potential strategy to reduce losses from biotic attacks. Plant cell walls perform crucial roles on many physiological processes, and under biotic stress, play crucial defensive roles as protecting barrier, as well as a source of integrity signalling molecules. Plant immunity has evolved a complex multi-layered system which first line of defence is initiated by conserved molecular patterns coming from pathogens, named pathogen-associated molecular patterns or PAMPs, or from their own corrupted cell walls due to pathogen invasion, named damaged-associated molecular patterns or DAMPs. Accumulating evidence from cell wall mutants has unveiled several components and mechanisms of plant innate immunity under biotic stresses, mostly in Arabidopsis, but still little is known from species with agronomic interest as strawberry. Our group has an established strawberry transgenic collection of cell wall mutants. Among them, RNAseq expression profiles of FaPG1 mutants has shown downregulation of other cell wall related genes than PG [1], but the mechanisms underneath required further investigation. FaPG genes code for enzymes with endo-PG activity related to oligogalacturonic acid (OGA) release, which would be associated to the changes in gene expression of other cell wall genes than FaPG. In this work, postharvest assays of FaPG1 fruits showed not only the increased fruit firmness typical of this mutant, but a better resistance to fungal infections by Botrytis cinerea, enhancing fruit shelf life in comparison with control fruits.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Plant Breeding Perspectives for Alfalfa (\u3cem\u3eMedicago sativa\u3c/em\u3e L.) Success in Warm Climates

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    Climate change can have major impacts on adaptation of forage species to agroecosystems around the world. The ability of breeders to select for traits that impart adaptability to climate resilience will be critical for the future of grasslands. Alfalfa (Medicago sativa L.) is the most important perennial forage legume in the world because of its relatively high yield and nutritional value. In Florida, nondormant cultivars were developed for improved adaptation to the state’s subtropical agroecosystem (‘Florida 66’, ‘Florida 77’, and ‘Florida 99’); however, these cultivars are not commercially available. Breeding efforts are underway to develop new nondormant alfalfa adapted to subtropical conditions. The main goal of the alfalfa breeding program at the University of Florida (UF) is to combine germplasm screening, genomics, enviromics, and phenomics to improve yield and persistence. The integration of multi-omics data can result in greater genetic gain by reducing the length of the breeding cycle and by increasing the size of breeding populations. The development of nondormant, persistent, and high yielding cultivars would be a big step towards establishing alfalfa systems in warmer climates

    mTOR pathway in papillary thyroid carcinoma: Different contributions of mTORC1 and mTORC2 complexes for tumor behavior and SLC5A5 mRNA expression

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    The mammalian target of rapamycin (mTOR) pathway is overactivated in thyroid cancer (TC). We previously demonstrated that phospho-mTOR expression is associated with tumor aggressiveness, therapy resistance, and lower mRNA expression of SLC5A5 in papillary thyroid carcinoma (PTC), while phospho-S6 (mTORC1 effector) expression was associated with less aggressive clinicopathological features. The distinct behavior of the two markers led us to hypothesize that mTOR activation may be contributing to a preferential activation of the mTORC2 complex. To approach this question, we performed immunohistochemistry for phospho-AKT Ser473 (mTORC2 effector) in a series of 182 PTCs previously characterized for phospho-mTOR and phospho-S6 expression. We evaluated the impact of each mTOR complex on SLC5A5 mRNA expression by treating cell lines with RAD001 (mTORC1 blocker) and Torin2 (mTORC1 and mTORC2 blocker). Phospho-AKT Ser473 expression was positively correlated with phospho-mTOR expression. Nuclear expression of phospho-AKT Ser473 was significantly associated with the presence of distant metastases. Treatment of cell lines with RAD001 did not increase SLC5A5 mRNA levels, whereas Torin2 caused a ~6 fold increase in SLC5A5 mRNA expression in the TPC1 cell line. In PTC, phospho-mTOR activation may lead to the activation of the mTORC2 complex. Its downstream effector, phospho-AKT Ser473, may be implicated in distant metastization, therapy resistance, and downregulation of SLC5A5 mRNA expression.Acknowledgments: This study was supported by FCT (“Portuguese Foundation for Science and Technology”) through PhD grants to Catarina Tavares (SFRH/BD/87887/2012), Ana Pestana (SFRH/BD/110617/2015), and Rui Batista (SFRH/BD/111321/2015) and by a CNPq PhD grant (“National Counsel of Technological and Scientific Development”, Brazil), Science without Borders, Process n# 237322/2012-9 for Luciana Ferreira. Miguel Melo received a grant from Genzyme for the research project “Molecular biomarkers of prognosis and response to therapy in differentiated thyroid carcinomas”. Further funding was obtained from FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operational Program for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the project "Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274), and by the project “Advancing cancer research: from basic acknowledgement to application”; NORTE-01-0145-FEDER-000029; “Projetos Estruturados de I&D&I, funded by Norte 2020-Programa Operacional Regional do Norte. This work was also financed by Sociedade Portuguesa de Endocrinologia Diabetes e Metabolismo through a grant “Prof. E. Limbert Sociedade Portuguesa de Endocrinologia Diabetes e Metabolismo/Sanofi-Genzyme in thyroid pathology”
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