128 research outputs found

    A new experiment for the determination of the 18F(p,alpha) reaction rate at nova temperatures

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    The 18F(p,alpha) reaction was recognized as one of the most important for gamma ray astronomy in novae as it governs the early 511 keV emission. However, its rate remains largely uncertain at nova temperatures. A direct measurement of the cross section over the full range of nova energies is impossible because of its vanishing value at low energy and of the short 18F lifetime. Therefore, in order to better constrain this reaction rate, we have performed an indirect experiment taking advantage of the availability of a high purity and intense radioactive 18F beam at the Louvain La Neuve RIB facility. We present here the first results of the data analysis and discuss the consequences.Comment: Contribution to the Classical Novae Explosions conference, Sitges, Spain, 20-24 May 2002, 5 pages, 3 figure

    A belgian survey on the diagnosis of asthma– COPD overlap syndrome

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    INTRODUCTION: Patients with chronic airway disease may present features of both asthma and COPD, commonly referred to as asthma-COPD overlap syndrome (ACOS). Recommendations on their diagnosis are diffuse and inconsistent. This survey aimed to identify consensus on criteria for diagnosing ACOS. METHODS: A Belgian expert panel developed a survey on ACOS diagnosis, which was completed by 87 pulmonologists. Answers chosen by >/=70% of survey respondents were considered as useful criteria for ACOS diagnosis. The two most frequently selected answers were considered as major criteria, others as minor criteria. The expert panel proposed a minimal requirement of two major criteria and one minor criterion for ACOS diagnosis. Respondents were also asked which criteria are important for considering inhaled corticosteroids prescription in a COPD patient. RESULTS: To diagnose ACOS in COPD patients, major criteria were "high degree of variability in airway obstruction over time (change in forced expiratory volume in 1 second >/=400 mL)" and "high degree of response to bronchodilators (>200 mL and >/=12% predicted above baseline)". Minor criteria were "personal/family history of atopy and/or IgE sensitivity to >/=1 airborne allergen", "elevated blood/sputum eosinophil levels and/or increased fractional exhaled nitric oxide", "diagnosis of asthma /=10 pack-years for (ex-)smokers"; minor criteria were "lack of response on acute bronchodilator test"; "reduced diffusion capacity"; "limited variability in airway obstruction"; "age >40 years"; "emphysema on chest computed tomography scan". CONCLUSION: Specific criteria were identified that may guide physicians to a more uniform diagnostic approach for ACOS in COPD or asthma patients. These criteria are largely similar to those used to prescribe inhaled corticosteroids in COPD

    Treatment failure and hospital readmissions in severe COPD exacerbations treated with azithromycin versus placebo - A post-hoc analysis of the BACE randomized controlled trial

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    Background: In the BACE trial, a 3-month (3 m) intervention with azithromycin, initiated at the onset of an infectious COPD exacerbation requiring hospitalization, decreased the rate of a first treatment failure (TF); the composite of treatment intensification (TI), step-up in hospital care (SH) and mortality. Objectives: (1) To investigate the intervention's effect on recurrent events, and (2) to identify clinical subgroups most likely to benefit, determined from the incidence rate of TF and hospital readmissions. Methods: Enrolment criteria included the diagnosis of COPD, a smoking history of ≥10 pack-years and ≥ 1 exacerbation in the previous year. Rate ratio (RR) calculations, subgroup analyses and modelling of continuous variables using splines were based on a Poisson regression model, adjusted for exposure time. Results: Azithromycin significantly reduced TF by 24% within 3 m (RR = 0.76, 95%CI:0.59;0.97, p = 0.031) through a 50% reduction in SH (RR = 0.50, 95%CI:0.30;0.81, p = 0.006), which comprised of a 53% reduction in hospital readmissions (RR = 0.47, 95%CI:0.27;0.80; p = 0.007). A significant interaction between the intervention, CRP and blood eosinophil count at hospital admission was found, with azithromycin significantly reducing hospital readmissions in patients with high CRP (> 50 mg/L, RR = 0.18, 95%CI:0.05;0.60, p = 0.005), or low blood eosinophil count (<300cells/μL, RR = 0.33, 95%CI:0.17;0.64, p = 0.001). No differences were observed in treatment response by age, FEV1, CRP or blood eosinophil count in continuous analyses. Conclusions: This post-hoc analysis of the BACE trial shows that azithromycin initiated at the onset of an infectious COPD exacerbation requiring hospitalization reduces the incidence rate of TF within 3 m by preventing hospital readmissions. In patients with high CRP or low blood eosinophil count at admission this treatment effect was more pronounced, suggesting a potential role for these biomarkers in guiding azithromycin therapy. Trial registration: ClinicalTrials.gov number. NCT02135354. © 2019 The Author(s)

    Search for molecular states in C-16

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    In order to search for a proposed alpha : 2n : alpha : 2n : alpha molecular structure in C-16 its break-up into Be-10 + He-6, Be-12 + alpha, He-8 + 2 alpha and He-6 + He-6 + alpha has been studied using a 560 MeV C-16 beam inelastically excited on a C-12 target. States in C-16 appear to be only weakly populated in this reaction

    Neutrons from the breakup of C-19

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    Neutrons arising from the breakup of a 30 MeV/nucleon C-19 beam on a tantalum target have been measured using the 98 element array DEMON. A narrow, forward peaked neutron angular distribution, with a corresponding momentum spread considerably smaller than those measured simultaneously for N-21, O-22 and F-24 was observed for charged fragments with Z < Z(proj). Interpreted in terms of the core-breakup reaction model, the results support the existence of a one neutron halo in C-19

    Evidences for resonance states in H-5

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    Resonance states of H-5 were investigated through the two-neutron transfer reaction t(t, P)(5) H. A triton beam at 57.5 MeV and a cryogenic liquid tritium target were used. The H-5 missing mass spectrum in triple coincidence, proton + triton + neutron, shows a resonance at 1.8 +/- 0.1 MeV above the t + 2n decay threshold. This energy is in good agreement with the result reported in Phys. Rev. Lett. 87 (2001) 092501. The resonance width, Gamma(intr) less than or equal to 0.5 MeV, is surprisingly small and difficult to reconcile with theory predictions. (C) 2003 Published by Elsevier B.V

    A new approach to a fast neutron facility

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    The facility is aimed at the production of a fast (40 to 75 MeV) monokinetic neutron beam, through the /sup 7/Li(p,n) reaction at 0 degrees . Contrary to the previous set-up, the incident charged beam is not bent by a magnet behind the Li target, but dumped and integrated in a Carbon Faraday cup. The target and the Faraday cup are enclosed in the center of a large iron shielding surrounded by a boron-load paraffin jacket.Anglai
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