765 research outputs found

    Higher order effects in the 16O(d,p)17O^{16}O(d,p)^{17}O and 16O(d,n)17F^{16}O(d,n)^{17}F transfer reactions

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    Full Coupled Channels Calculations were performed for the 16O(d,n)17F^{16}O(d,n)^{17}F and 16O(d,p)17O^{16}O(d,p)^{17}O transfer reactions at several deuteron incident energies from Elab=2.29E_{lab}=2.29 MeV up to 3.27 MeV. A strong polarization effect between the entrance channel and the transfer channels 16O(d,n)17F(1/2+,0.495)^{16}O(d,n)^{17}F(1/2^{+},0.495) and 16O(d,p)17O(1/2+,0.87)^{16}O(d,p)^{17}O(1/2^{+},0.87) was observed. This polarization effect had to be taken into account in order to obtain realistic spectroscopic factors from these reactions.Comment: 15 papes, 13 figures, accepted for publication in Phys. Rev.

    Dynamic model and stationary shapes of fluid vesicles

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    A phase-field model that takes into account the bending energy of fluid vesicles is presented. The Canham-Helfrich model is derived in the sharp-interface limit. A dynamic equation for the phase-field has been solved numerically to find stationary shapes of vesicles with different topologies and the dynamic evolution towards them. The results are in agreement with those found by minimization of the Canham-Helfrich free energy. This fact shows that our phase-field model could be applied to more complex problems of instabilities.Comment: Accepted for publication in EPJE. 9 pages, 7 figure

    The effects of a high-protein, high-calorie, fiber- and fructo-oligosaccharide-enriched enteral formula on nutritional status, bowel habits and tolerance: Safety and effectiveness of enteral nutrition in elderly spanish patients (Sens study)

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    Background: Enteral nutrition (EN) is an effective nutritional intervention for patients at risk of malnutrition or malnourished. However, complications such as gastrointestinal intolerance, hyperglycemia or refeeding syndrome can be triggered by EN. Aim: To investigate the effects of a tube feeding formula (TFF) on patients’ nutritional status, biochemical status, bowel habits and safety. Methodology: Observational, prospective and multicenter study. Patients = 18 years, undernourished or at nutritional risk, who were prescribed a high-calorie, high-protein, fiber-fortified TFF were included. Patients were evaluated over a period of eight weeks (baseline [V1], four weeks [V2] and eight weeks [V3]). Results: A statistically significant increase in weight (1.5 kg), body mass index (0.6 kg/m2) and nutritional intake (59.7 kcal/day) was observed between V1 and V2. Between V1 and V3, there was a statistically significant decrease in the percentage of individuals with abnormal biochemical markers for glucose, potassium, total protein and albumin. The number of patients’ bowel movements remained stable throughout the study with a mean of 1.1 daily bowel movements. Conclusion: The TFF was safe and well tolerated, improving patients’ nutritional status without altering patients’ bowel habits. Introducción: la nutrición enteral es una intervención efectiva para pacientes desnutridos o en riesgo de sufrir desnutrición. Sin embargo, puede desencadenar complicaciones como intolerancia gastrointestinal, hiperglicemia o síndrome de realimentación. Objetivo: investigar los efectos de una fórmula de nutrición enteral por sonda en el estado nutricional y bioquímico, hábitos gastrointestinales y seguridad de los pacientes. Metodología: estudio observacional, prospectivo y multicéntrico. Se incluyeron pacientes = 18 años, desnutridos o en riesgo de desnutrición, tributarios de recibir una fórmula de nutrición enteral hipercalórica, hiperproteica, y rica en fibra y fructooligosacáridos. Los pacientes fueron evaluados durante 8 semanas en 3 visitas (V1, inicial; V2, 4 semanas; V3, 8 semanas). Resultados: entre V1 y V2 se observó un incremento estadísticamente significativo en peso (1, 5 kg), índice de masa corporal (0, 6 kg/m2) e ingesta calórica (59, 7 kcal/día). Entre V1 y V3, existió un descenso en el porcentaje de pacientes con valores anormales de glucosa, potasio, proteína total y albúmina. Los hábitos intestinales se mantuvieron estables durante el estudio (1, 1 deposiciones diarias de media). Conclusión: la fórmula fue segura, tolerada, y mejoró el estado nutricional del paciente sin alterar los hábitos intestinales

    Spectroscopy of 18^{18}Na: Bridging the two-proton radioactivity of 19^{19}Mg

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    The unbound nucleus 18^{18}Na, the intermediate nucleus in the two-proton radioactivity of 19^{19}Mg, was studied by the measurement of the resonant elastic scattering reaction 17^{17}Ne(p,17^{17}Ne)p performed at 4 A.MeV. Spectroscopic properties of the low-lying states were obtained in a R-matrix analysis of the excitation function. Using these new results, we show that the lifetime of the 19^{19}Mg radioactivity can be understood assuming a sequential emission of two protons via low energy tails of 18^{18}Na resonances

    Electrostatic and electrokinetic contributions to the elastic moduli of a driven membrane

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    We discuss the electrostatic contribution to the elastic moduli of a cell or artificial membrane placed in an electrolyte and driven by a DC electric field. The field drives ion currents across the membrane, through specific channels, pumps or natural pores. In steady state, charges accumulate in the Debye layers close to the membrane, modifying the membrane elastic moduli. We first study a model of a membrane of zero thickness, later generalizing this treatment to allow for a finite thickness and finite dielectric constant. Our results clarify and extend the results presented in [D. Lacoste, M. Cosentino Lagomarsino, and J. F. Joanny, Europhys. Lett., {\bf 77}, 18006 (2007)], by providing a physical explanation for a destabilizing term proportional to \kps^3 in the fluctuation spectrum, which we relate to a nonlinear (E2E^2) electro-kinetic effect called induced-charge electro-osmosis (ICEO). Recent studies of ICEO have focused on electrodes and polarizable particles, where an applied bulk field is perturbed by capacitive charging of the double layer and drives flow along the field axis toward surface protrusions; in contrast, we predict "reverse" ICEO flows around driven membranes, due to curvature-induced tangential fields within a non-equilibrium double layer, which hydrodynamically enhance protrusions. We also consider the effect of incorporating the dynamics of a spatially dependent concentration field for the ion channels.Comment: 22 pages, 10 figures. Under review for EPJ

    Toward Forecasting Volcanic Eruptions using Seismic Noise

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    During inter-eruption periods, magma pressurization yields subtle changes of the elastic properties of volcanic edifices. We use the reproducibility properties of the ambient seismic noise recorded on the Piton de la Fournaise volcano to measure relative seismic velocity variations of less than 0.1 % with a temporal resolution of one day. Our results show that five studied volcanic eruptions were preceded by clearly detectable seismic velocity decreases within the zone of magma injection. These precursors reflect the edifice dilatation induced by magma pressurization and can be useful indicators to improve the forecasting of volcanic eruptions.Comment: Supplementary information: http://www-lgit.obs.ujf-grenoble.fr/~fbrengui/brenguier_SI.pdf Supplementary video: http://www-lgit.obs.ujf-grenoble.fr/~fbrengui/brenguierMovieVolcano.av
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