451 research outputs found

    The 3^3He(e, e'd)p Reaction in qω\omega-constant Kinematics

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    The cross section for the 3^3He(e, e'd)p reaction has been measured as a function of the missing momentum pmp_m in qω\omega -constant kinematics at beam energies of 370 and 576 MeV for values of the three-momentum transfer qq of 412, 504 and 604 \mevc. The L(+TT), T and LT structure functions have been separated for qq = 412 and 504 \mevc. The data are compared to three-body Faddeev calculations, including meson-exchange currents (MEC), and to calculations based on a covariant diagrammatic expansion. The influence of final-state interactions and meson-exchange currents is discussed. The pmp_m-dependence of the data is reasonably well described by all calculations. However, the most advanced Faddeev calculations, which employ the AV18 nucleon-nucleon interaction and include MEC, overestimate the measured cross sections, especially the longitudinal part, and at the larger values of qq. The diagrammatic approach gives a fair description of the cross section, but under(over)estimates the longitudinal (transverse) structure function.Comment: 17 pages, 7 figure

    Climate-controlled root zone parameters show potential to improve water flux simulations by land surface models

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    The root zone storage capacity (Sr) is the maximum volume of water in the subsurface that can potentially be accessed by vegetation for transpiration. It influences the seasonality of transpiration as well as fast and slow runoff processes. Many studies have shown that Sr is heterogeneous as controlled by local climate conditions, which affect vegetation strategies in sizing their root system able to support plant growth and to prevent water shortages. Root zone parameterization in most land surface models does not account for this climate control on root development and is based on lookup tables that prescribe the same root zone parameters worldwide for each vegetation class. These lookup tables are obtained from measurements of rooting structure that are scarce and hardly representative of the ecosystem scale. The objective of this research is to quantify and evaluate the effects of a climate-controlled representation of Sr on the water fluxes modeled by the Hydrology Tiled ECMWF Scheme for Surface Exchanges over Land (HTESSEL) land surface model. Climate-controlled Sr is estimated here with the “memory method” (MM) in which Sr is derived from the vegetation's memory of past root zone water storage deficits. Sr,MM is estimated for 15 river catchments over Australia across three contrasting climate regions: tropical, temperate and Mediterranean. Suitable representations of Sr,MM are implemented in an improved version of HTESSEL (Moisture Depth – MD) by accordingly modifying the soil depths to obtain a model Sr,MD that matches Sr,MM in the 15 catchments. In the control version of HTESSEL (CTR), Sr,CTR is larger than Sr,MM in 14 out of 15 catchments. Furthermore, the variability among the individual catchments of Sr,MM (117–722 mm) is considerably larger than of Sr,CTR (491–725 mm). The climate-controlled representation of Sr in the MD version results in a significant and consistent improvement of the modeled monthly seasonal climatology (1975–2010) and interannual anomalies of river discharge compared with observations. However, the effects on biases in long-term annual mean river discharge are small and mixed. The modeled monthly seasonal climatology of the catchment discharge improved in MD compared to CTR: the correlation with observations increased significantly from 0.84 to 0.90 in tropical catchments, from 0.74 to 0.86 in temperate catchments and from 0.86 to 0.96 in Mediterranean catchments. Correspondingly, the correlations of the interannual discharge anomalies improve significantly in MD from 0.74 to 0.78 in tropical catchments, from 0.80 to 0.85 in temperate catchments and from 0.71 to 0.79 in Mediterranean catchments. The results indicate that the use of climate-controlled Sr,MM can significantly improve the timing of modeled discharge and, by extension, also evaporation fluxes in land surface models. On the other hand, the method has not been shown to significantly reduce long-term climatological model biases over the catchments considered for this study.</p

    Encouraging survival rates in patients with acute myocardial infarction treated with an intra-aortic balloon pump

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    Objective To evaluate a 30-day and long-term outcome of patients with acute myocardial infarction (AMI) treated with intra-aortic balloon pump (IABP) counterpulsation and to identify predictors of a 30-day and long-term all-cause mortality. Methods Retrospective cohort study of 437 consecutive AMI patients treated with IABP between January 1990 and June 2004. A Cox proportional hazards model was used to identify predictors of a 30-day and long-term all-cause mortality. Results Mean age of the study population was 61±11 years, 80% of the patients were male, and 68% had cardiogenic shock. Survival until IABP removal after successful haemodynamic stabilisation was 78% (n=341). Cumulative 30-day survival was 68%. Median follow-up was 2.9 years (range, 6 months to 15 years). In patients who survived until IABP removal, cumulative 1-, 5-, and 10-year survival was 75%

    The effect of high dose inhaled corticosteroids on wheeze in infants after respiratory syncytial virus infection: randomised double blind placebo controlled trial

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    Objective To determine whether early initiated anti-inflammatory therapy with prolonged high dose inhaled glucocorticoids influences the occurrence and severity of recurrent wheeze after respiratory syncytial virus related lower respiratory tract infections

    The proton and deuteron F_2 structure function at low Q^2

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    Measurements of the proton and deuteron F2F_2 structure functions are presented. The data, taken at Jefferson Lab Hall C, span the four-momentum transfer range 0.06<Q2<2.80.06 < Q^2 < 2.8 GeV2^2, and Bjorken xx values from 0.009 to 0.45, thus extending the knowledge of F2F_2 to low values of Q2Q^2 at low xx. Next-to-next-to-leading order calculations using recent parton distribution functions start to deviate from the data for Q2<2Q^2<2 GeV2^2 at the low and high xx-values. Down to the lowest value of Q2Q^2, the structure function is in good agreement with a parameterization of F2F_2 based on data that have been taken at much higher values of Q2Q^2 or much lower values of xx, and which is constrained by data at the photon point. The ratio of the deuteron and proton structure functions at low xx remains well described by a logarithmic dependence on Q2Q^2 at low Q2Q^2.Comment: 3 figures, submitted pape

    Femtometer Toroidal Structures in Nuclei

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    The two-nucleon density distributions in states with isospin T=0T=0, spin SS=1 and projection MSM_S=0 and ±\pm1 are studied in 2^2H, 3,4^{3,4}He, 6,7^{6,7}Li and 16^{16}O. The equidensity surfaces for MSM_S=0 distributions are found to be toroidal in shape, while those of MSM_S=±\pm1 have dumbbell shapes at large density. The dumbbell shapes are generated by rotating tori. The toroidal shapes indicate that the tensor correlations have near maximal strength at r<2r<2 fm in all these nuclei. They provide new insights and simple explanations of the structure and electromagnetic form factors of the deuteron, the quasi-deuteron model, and the dpdp, dddd and αd\alpha d LL=2 (DD-wave) components in 3^3He, 4^4He and 6^6Li. The toroidal distribution has a maximum-density diameter of \sim1 fm and a half-maximum density thickness of \sim0.9 fm. Many realistic models of nuclear forces predict these values, which are supported by the observed electromagnetic form factors of the deuteron, and also predicted by classical Skyrme effective Lagrangians, related to QCD in the limit of infinite colors. Due to the rather small size of this structure, it could have a revealing relation to certain aspects of QCD.Comment: 35 pages in REVTeX, 25 PostScript figure

    Clinical effects of the three CFTR potentiator treatments curcumin, genistein and ivacaftor in patients with the CFTR-S1251N gating mutation

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    Contains fulltext : 229853.pdf (Publisher’s version ) (Closed access)BACKGROUND: The natural food supplements curcumin and genistein, and the drug ivacaftor were found effective as CFTR potentiators in the organoids of individuals carrying a S1251N gating mutation, possibly in a synergistic fashion. Based on these in vitro findings, we evaluated the clinical efficacy of a treatment with curcumin, genistein and ivacaftor, in different combinations. METHODS: In three multi-center trials people with CF carrying the S1251N mutation were treated for 8 weeks with curcumin+genistein, ivacaftor and ivacaftor+genistein. We evaluated change in lung function, sweat chloride concentration, CFQ-r, BMI and fecal elastase to determine the clinical effect. We evaluated the pharmacokinetic properties of the compounds by evaluating the concentration in plasma collected after treatment and the effect of the same plasma on the intestinal organoids. RESULTS: A clear clinical effect of treatment with ivacaftor was observed, evidenced by a significant improvement in clinical parameters. In contrast we observed no clear clinical effect of curcumin and/or genistein, except for a small but significant reduction in sweat chloride and airway resistance. Plasma concentrations of the food supplements were low, as was the response of the organoids to this plasma. CONCLUSIONS: We observed a clear clinical effect of treatment with ivacaftor, which is in line with the high responsiveness of the intestinal organoids to this drug. No clear clinical effect was observed of the treatment with curcumin and/or genistein, the low plasma concentration of these compounds emphasizes that pharmacokinetic properties of a compound have to be considered when in vitro experiments are performed
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