237 research outputs found

    Progress in the determination of the J/ψπJ/\psi-\pi cross section

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    Improving previous calculations, we compute the J/ψπcharmedmesonsJ/\psi \pi\to {charmed mesons} cross section using QCD sum rules. Our sum rules for the J/ψπDˉDJ/\psi \pi\to \bar{D} D^*, DDˉD \bar{D}^*, DˉD{\bar D}^* D^* and DˉD{\bar D} D hadronic matrix elements are constructed by using vaccum-pion correlation functions, and we work up to twist-4 in the soft-pion limit. Our results suggest that, using meson exchange models is perfectly acceptable, provided that they include form factors and that they respect chiral symmetry. After doing a thermal average we get 0.3\sim 0.3 mb at T=150\MeV.Comment: 22 pages, RevTeX4 including 7 figures in ps file

    Virtual Meson Cloud of the Nucleon and Intrinsic Strangeness and Charm

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    We have applied the Meson Cloud Model (MCM) to calculate the charm and strange antiquark distribution in the nucleon. The resulting distribution, in the case of charm, is very similar to the intrinsic charm momentum distribution in the nucleon. This seems to corroborate the hypothesis that the intrinsic charm is in the cloud and, at the same time, explains why other calculations with the MCM involving strange quark distributions fail in reproducing the low x region data. From the intrinsic strange distribution in the nucleon we have extracted the strangeness radius of the nucleon, which is in agreement with other meson cloud calculations.Comment: 9 pages RevTex, 4 figure

    Metabolic Profile and Cardiovascular Risk in a Population of Renal transplant recipients

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    Introduction. Cardiovascular disease is more common in renal transplant recipients (RTRs) than in the general population, and is the major cause of both graft loss and patient death in RTRs. Objectives. This study aimed to characterize the cardiovascular risk factors, calculate the 7-year risk for major adverse cardiac events and the 7-year risk for death in a population of RTRs using a cardiovascular risk calculator, and determine the main cardiovascular risk factors associated with increased prediction of major adverse cardiac event (MACE) and death. Patients. This is a retrospective review of clinical data from 121 RTRs who are in follow-up programs at our institution, and who had a functioning and stable graft for longer than 6 months. Results. Among 121 adult patients followed at our institution (59.5% males, mean age of 49.6 13.8 years, mean times for functioning grafts were 105 73.5 mo), 86.8% had hypertension, 19.8% had diabetes, 24.8% were current or former smokers, 61.9% had increased body mass index, and 71% had dyslipidemia. The 7-year risk for MACE was more than 10% in 38 (31.4%) patients with age, diabetes, and smoke being independent risk predictors. The 7-year risk for death was more than 10% in 56 (46.3%) patients with age, diabetes, blood pressure, smoking, and male gender being independent risk predictors. Conclusion. There is a high prevalence of cardiovascular risk factors in a population of RTRs, and there is increased risk for MACE and death. Accurate risk prediction is important for physician decision support and patient education, promoting improved cardiovascular health of RTRs, and thus prolonging the survival of both patients and graft.info:eu-repo/semantics/publishedVersio

    Diffractive Dissociation In The Interacting Gluon Model

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    We have extended the Interacting Gluon Model (IGM) to calculate diffractive mass spectra generated in hadronic collisions. We show that it is possible to treat both diffractive and non-diffractive events on the same footing, in terms of gluon-gluon collisions. A systematic analysis of available data is performed. The energy dependence of diffractive mass spectra is addressed. They show a moderate narrowing at increasing energies. Predictions for LHC energies are presented.Comment: 12 pages, latex, 14 figures (PostScript Files included); accepted for publication in Phys. Rev. D (Feb.97

    Leading nucleon and inelasticity in hadron-nucleus interactions

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    We present in this paper a calculation of the average proton-nucleus ine- lasticity. Using an Iterative Leading Particle Model and the Glauber model, we relate the leading particle distribution in nucleon-nucleus interactions with the respective one in nucleon-proton collisions. To describe the leading particle distribution in nucleon-proton collisions, we use the Regge-Mueller formalism. To appear in Journal of Physics G.Comment: 11 pages, 2 figure

    Efeito de concentrações de sacarose e de meio de cultura (8s) sobre o crescimento de mandioca cultivar mico (bgm 1014) conservadas in vitro.

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    A produção de mandioca é uma atividade agrícola de alta relevância no Brasil por sua importância alimentícia e econômica. Porém, a baixa taxa de multiplicação associado os fatores biológicos, torna-se um limitante para uma melhor exploração desse cultivo.Diversas alternativas vêm sendo adotadas para superar esse problema, a micropropagação é uma delas que por sua vez apresenta as vantagens de prevenir a disseminação de pragas e doenças de uma geração para outra e proporcionar um número elevado de plantas num curto espaço de tempo. O objetivo deste trabalho foi avaliar o potencial de micropropagação da variedade Mico, coletada em Itajaí Santa Catarina, em diferentes concentrações de meio 8S e dosagens de sacarose. Os explantes apresentaram maior desempenho em meio 8S ½ na concentração de 0,4 g.L-1 de sacarose. Contudo, a taxa de sobrevivência para manutenção do material foi melhor quando utilizou-se o meio (8S) ¼ na concentração de 0,8 g.L-1

    Heterozygosity, adaptability, and phenotypic stability of sweet sorghum genotypes.

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    Sweet sorghum (Sorghum bicolor L.) is a promising energy crop for bioethanol production. This study aimed to investigate the influence of genetic structure on the adaptability and phenotypic stability of sweet sorghum lines and hybrids regarding the main agro-industrial traits, as well as selecting hybrids that associate high ethanol yield and yield stability in different growing environments. A total of 45 genotypes were evaluated in experiments conducted in a 5×9 triple alpha lattice design in three locations in the state of Minas Gerais, Brazil. The following traits were measured: fresh matter production, juice extraction percentage, total soluble solids content, tons of Brix per hectare, and ethanol production. Adaptability and phenotypic stability were assessed by the Wricke and Annicchiarico methods. Sweet sorghum adaptability and phenotypic stability depend on genotype genetic structure, with hybrids being more stable than parental lines. Additionally, H2x9 and H3x8 were the most promising hybrids

    Tetracyclic thioxanthene derivatives: Studies on fluorescence and antitumor activity

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    Thioxanthones are bioisosteres of the naturally occurring xanthones. They have been described for multiple activities, including antitumor. As such, the synthesis of a library of thioxanthones was pursued, but unexpectedly, four tetracyclic thioxanthenes with a quinazoline– chromene scaffold were obtained. These compounds were studied for their human tumor cell growth inhibition activity, in the cell lines A375-C5, MCF-7 and NCI-H460. Photophysical studies were also performed. Two of the compounds displayed GI50 values below 10 µM for the three tested cell lines, and structure–activity relationship studies were established. Three compounds presented similar wavelengths of absorption and emission, characteristic of dyes with a push-pull character. The structures of two compounds were elucidated by X-ray crystallography. Two tetracyclic thioxanthenes emerged as hit compounds. One of the two compounds accumulated intracellularly as a bright fluorescent dye in the green channel, as analyzed by both fluorescence microscopy and flow cytometry, making it a promising theranostic cancer drug candidate.This research was partially supported by the Strategic Funding UIDB/04423/2020, UIDP/04423/2020 (Group of Natural Products and Medicinal Chemistry‐CIIMAR) and under the project PTDC/SAU‐PUB/28736/2017 (reference POCI‐01‐0145‐FEDER‐028736), co‐financed by COMPETE 2020, Portugal 2020 and the European Union through the ERDF and by FCT through national funds. Fernando Durães acknowledges his FCT grant (SFRH/BD/144681/2019). Hassan Bousbaa acknowledges funding from CESPU (IMPLDEBRIS‐PL‐3RL‐IINFACTS‐2019). This research was funded by Fundação para a Ciência e a Tecnologia (FCT) through research units UIDB/50006/2020, UID/CTM/50011/2019, UIDB/50011/2020 & UIDP/50011/2020 and by the European Union (FEDER program) through project CENTRO‐01‐0145‐FEDER‐000003

    Efeito de concentrações de sacarose e de meio de cultura (8s) sobre a taxa de crescimento de e mandioca cultivar olho roxo (bgm 0036) conservadas in vitro.

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    A mandioca é uma cultura de grande na alimentação humana e animal, sendo que esta pode ser cultivada em várias regiões do país. Com o advento do melhoramento, diferentes cultivares foram desenvolvidas e, com isso, há uma necessidade tanto de manutenção destas quanto de multiplicação em larga escala das mesmas. O objetivo deste trabalho foi avaliar concentrações 1/1, ½ e ¼ de meio 8S combinados com diferentes doses de sacarose na taxa de crescimento de mandioca cultivada in vitro, avaliando-se altura de plantas, número de folhas vivas e mortas, número de ápices vivos e mortos e número de gemas. Os explantes apresentaram maior desempenho em meio de cultura com ¼ de 8S e uma concentração de 0,4 g.L-1 de sacarose. Contudo, a taxa de sobrevivência para manutenção do material foi melhor quando utilizou-se o meio 8S em sua composição original, na concentração de 0,4 g.L-1
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