8,769 research outputs found

    Corrections to the SU(3)×SU(3){\bf SU(3)\times SU(3)} Gell-Mann-Oakes-Renner relation and chiral couplings L8rL^r_8 and H2rH^r_2

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    Next to leading order corrections to the SU(3)×SU(3)SU(3) \times SU(3) Gell-Mann-Oakes-Renner relation (GMOR) are obtained using weighted QCD Finite Energy Sum Rules (FESR) involving the pseudoscalar current correlator. Two types of integration kernels in the FESR are used to suppress the contribution of the kaon radial excitations to the hadronic spectral function, one with local and the other with global constraints. The result for the pseudoscalar current correlator at zero momentum is ψ5(0)=(2.8±0.3)×103GeV4\psi_5(0) = (2.8 \pm 0.3) \times 10^{-3} GeV^{4}, leading to the chiral corrections to GMOR: δK=(55±5)\delta_K = (55 \pm 5)%. The resulting uncertainties are mostly due to variations in the upper limit of integration in the FESR, within the stability regions, and to a much lesser extent due to the uncertainties in the strong coupling and the strange quark mass. Higher order quark mass corrections, vacuum condensates, and the hadronic resonance sector play a negligible role in this determination. These results confirm an independent determination from chiral perturbation theory giving also very large corrections, i.e. roughly an order of magnitude larger than the corresponding corrections in chiral SU(2)×SU(2)SU(2) \times SU(2). Combining these results with our previous determination of the corrections to GMOR in chiral SU(2)×SU(2)SU(2) \times SU(2), δπ\delta_\pi, we are able to determine two low energy constants of chiral perturbation theory, i.e. L8r=(1.0±0.3)×103L^r_8 = (1.0 \pm 0.3) \times 10^{-3}, and H2r=(4.7±0.6)×103H^r_2 = - (4.7 \pm 0.6) \times 10^{-3}, both at the scale of the ρ\rho-meson mass.Comment: Revised version with minor correction

    Increased adiposity appraised with cun-bae is highly predictive of incident hypertension. The sun project

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    Overweight and obesity are growing worldwide and strongly associated with hypertension. The Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE) index is proposed as an optimal indicator of body fatness. We aimed to investigate the association of body fat as captured by the CUN-BAE index with incident hypertension in a Mediterranean population. We assessed 15,950 participants of the SUN (Seguimiento Universidad de Navarra) prospective cohort (63.7% women) initially free of hypertension. Participants completed follow-up questionnaires biennially. A validated 136-item food-frequency questionnaire was administered at baseline. We used Cox models adjusted for multiple confounders. Among 12.3 years of median follow-up (interquartile range: 8.3, 15.0 years), 2160 participants reported having received a diagnosis of hypertension. We observed a strong direct association between progressively higher the CUN-BAE index at baseline and incident hypertension during follow-up in multivariable-adjusted models for men and women, even after further adjustment for BMI ≥ 30 kg/m2, showing a significant association also in non-obese participants. For each 2-unit increase in the CUN-BAE index, hypertension risk increased by 27% and 29% in men and women, respectively. The results remained significant when considering longitudinal repeated measures of changes in body fat assessed with the CUN-BAE index among the different biennial follow-up questionnaires. Our results emphasize the importance of reducing and maintaining a low body fat to prevent hypertension

    The origin of the Acheulean: the 1.7 million-year-old site of FLK West, Olduvai Gorge (Tanzania)

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    The appearance of the Acheulean is one of the hallmarks of human evolution. It represents the emergence of a complex behavior, expressed in the recurrent manufacture of large-sized tools, with standardized forms, implying more advance forethought and planning by hominins than those required by the precedent Oldowan technology. The earliest known evidence of this technology dates back to c. 1.7 Ma. and is limited to two sites (Kokiselei [Kenya] and Konso [Ethiopia]), both of which lack fauna. The functionality of these earliest Acheulean assemblages remains unknown. Here we present the discovery of another early Acheulean site also dating to c. 1.7 Ma from Olduvai Gorge. This site provides evidence of the earliest steps in developing the Acheulean technology and is the oldest Acheulean site in which stone tools occur spatially and functionally associated with the exploitation of fauna. Simple and elaborate large-cutting tools (LCT) and handaxes co-exist at FLK West, showing that complex cognition was present from the earliest stages of the Acheulean. Here we provide a detailed technological study and evidence of the use of these tools on the butchery and consumption of fauna, probably by early Homo erectus sensu lato

    Microsatellite alterations and TP53 mutations in plasma DNA of small-cell lung cancer patients: Follow-up study and prognostic significance

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    Background: Small-cell lung cancer (SCLC), one of the major types of lung cancer, is associated with many different somatic molecular genetic changes. These alterations, observed in tumor DNA, have also been identified in the plasma DNA of patients. We undertook the present study to make a prospective investigation into the correlation between abnormal plasma DNA and patient survival. Patients and methods: Thirty-five patients with SCLC were selected after histological diagnosis. Polymorphic markers (ACTBP2, UT762 and AR) were chosen for their reported high rate of alterations in SCLC and analyzed in tumor tissue, normal blood cells and plasma DNA. Furthermore, we looked for mutations of the TP53 gene in tumor and plasma DNA. Results: In 25 patients (71%) at least one molecular change precisely matching that of the primary tumor was detected in the plasma DNA. No difference in survival was observed between patients with aberrant plasma DNA and patients without plasma DNA alterations. However, patients with microsatellite modifications and TP53 mutations concomitantly, showed a significant difference (P = 0.02) in survival compared with patients bearing only one of these molecular changes. In 15 cases it was possible to find a correlation either between tumor response and disappearance of abnormal plasma DNA, or tumor progression and persistence of plasma DNA alterations. Conclusions: Free plasma DNA with molecular alterations is present to a high degree in plasma DNA of SCLC patients and may have a role as a prognostic facto

    Milky Way Demographics with the VVV Survey II. Color Transformations and Near-Infrared Photometry for 136 Million Stars in the Southern Galactic Disk

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    The new multi-epoch near-infrared VVV survey (VISTA Variables in the Via Lactea) is sampling 562 sq. deg of the Galactic bulge and adjacent regions of the disk. Accurate astrometry established for the region surveyed allows the VVV data to be merged with overlapping surveys (e.g., GLIMPSE, WISE, 2MASS, etc.), thereby enabling the construction of longer baseline spectral energy distributions for astronomical targets. However, in order to maximize use of the VVV data, a set of transformation equations are required to place the VVV JHKs photometry onto the 2MASS system. The impetus for this work is to develop those transformations via a comparison of 2MASS targets in 152 VVV fields sampling the Galactic disk. The transformation coefficients derived exhibit a reliance on variables such as extinction. The transformed data were subsequently employed to establish a mean reddening law of E_{J-H}/E_{H-Ks}=2.13 +/- 0.04, which is the most precise determination to date and merely emphasizes the pertinence of the VVV data for determining such important parameters.Comment: 24 pages, 12 figures, published in A&

    Mutational status of K- ras and TP53 genes in primary sarcomas of the heart

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    We investigated three patients with cardiac angiosarcomas and two with cardiac rhabdomyosarcomas, all for mutations at exons 5, 6, 7 and 8 of the p53 gene and at exon 1 of K- ras. No point mutations were observed in the p53 gene in any of the five cases; however, at exon 1 of K- ras, three patients (60%) presented the same mutation at the first base of codon 13 (G to A transition). Interestingly, this mutation was detected in both rhabdomyosarcoma and angiosarcoma histologic sarcoma types. © 2000 Cancer Research Campaig

    Lipase assay in yarrowia lipolytica

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    Lipases (triacylglycerol acyl hydrolases, EC 3. 1.1.3) are key enzymes in fat metabolism produced by microorganisms, plants, and animals that catalyze the breakdown of triacylglycerols to free fatty adds and glycerol. In Y. lipolytica severaJ genes encoding lipases have been isoiated,LlP2 coding for a secreted lipase (Pignede et al. 1000) and LlPl and LIP3 encoding two lipase genes of the carboxylesrerase family (Choupina et al. 1999). Lipase expression was repressed by glucose and induced by fatty acids and olive oil
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