7,365 research outputs found

    Few-body decay and recombination in nuclear astrophysics

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    Three-body continuum problems are investigated for light nuclei of astrophysical relevance. We focus on three-body decays of resonances or recombination via resonances or the continuum background. The concepts of widths, decay mechanisms and dynamic evolution are discussed. We also discuss results for the triple α\alpha decay in connection with 2+2^+ resonances and density and temperature dependence rates of recombination into light nuclei from α\alpha-particles and neutrons.Comment: 9 pages, 8 figures. Proceedings of the 21st European Few Body Conference held in Salamanca (Spain) in August-September 201

    Composition of soil solution in the Puentes coal mine dump (NW Spain) during its reclamation

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    [Resumen] Se estudia la disolución de suelos de mina (obtenida por desplazamiento en columna según ADAMS, 1974) en la escombrera exterior de la explotaci6n de lignito pardo de As Pontes (La Coruña). os resultados muestran un amplio rango de variación en todos los parámetros analizados. Así podemos encontrar ambientes desde fuertemente ácidos (pH = 1.5) hasta alcalinos (pH = 8.5), asociándose los valores más bajos a materiales originales con mayor contenido en sulfuros. Los medios más ácidos son los que presentan los valores más elevados de Al, Fe y metales pesados. La conductividad eléctrica de la disoluci6n es muy elevada (superior a 500 uS cm-1), presentando una correlación muy significativa con el sulfato (r = 0.84), unión mayoritario que frecuentemente supera los 1000 mg L-l..[Abstract] Soil solution of the coal mine dump of As Pontes (NW Spain) is studied. Results show a wide variation on every parameters analized. pH values range from strong acidic (pH = 1.5) to alcaline (pH = 8.5). The lowest pH are associated to the highest sulphide content in the original wastes. The most acidic environments have the higest aluminium, iron and heavy metals levels. Electric conductivity is elevated (> 500 uS cm-1) and shows a good correlation (r = 0.84) with sulphate content, the main anion in this soil solution

    Анализ проблем инновационного развития медицины в Украине

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    Проанализированы проблемы, тормозящие развитие инновационной деятельности в медицине Украины, и внесены предложения по их устранению.Проаналізовано проблеми, які стримують розвиток інноваційної діяльності в медицині України, і внесено пропозиції щодо їх усунення.The paper contains an analysis of barriers for innovation in the Ukrainian medical sector, with propositions for their elimination

    Testosterone and Cholesterol Vasodilation of Rat Aorta Involves L-Type Calcium Channel Inhibition

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    Testosterone has rapid nongenomic vasodilator effects which could be involved in protective cardiovascular actions. Several authors suggested specific mechanisms to explain this effect, but this matter was not clarified yet. We studied the actions of testosterone and cholesterol on endothelium-denuded rat aorta and their effects on the L-type Ca2+ current (ICa,L) and potassium current (IK). Testosterone (1–100 μM) totally relaxed, in a rapid and concentration-dependent way, the aortic rings contracted by KCl or by (−)-Bay K8644 (BAY). Cholesterol also fully relaxed the contractions induced by KCl. None of the potassium channel antagonists tested (glibenclamide, tetraethylammonium and 4-aminopyridine) modified significantly the relaxant effect of testosterone. The antagonist of classic testosterone receptors, flutamide, did not modify the vasorelaxant effect of testosterone. Furthermore, testosterone and cholesterol inhibited either basal and BAY-stimulated ICa,L in A7r5 cells and they have no effects on IK. In summary, our results demonstrate that cholesterol and testosterone relax rat aorta by inhibiting LTCC. This effect of testosterone is not mediated by the classic hormone receptor or by potassium channel activation. These results suggest that the vasodilator mechanism of cholesterol and testosterone is the same

    Decay of low-lying 12C resonances within a 3alpha cluster model

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    We compute energy distributions of three α\alpha-particles emerging from the decay of 12^{12}C resonances by means of the hyperspherical adiabatic expansion method combined with complex scaling. The large distance continuum properties of the wave functions are crucial and must be accurately calculated. The substantial changes from small to large distances determine the decay mechanisms. We illustrate by computing the energy distributions from decays of the 1+1^{+} and 33^--resonances in 12^{12}C. These states are dominated by direct and sequential decays into the three-body continuum respectively.Comment: 5 pages, 3 figures. Proceedings of the Clusters '07 conference held in Stratford-upon-Avon in September 200

    Correlation between magnetic interactions and domain structure in A1 FePt ferromagnetic thin films

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    We have investigated the relationship between the domain structure and the magnetic interactions in a series of FePt ferromagnetic thin films of varying thickness. As-made films grow in the magnetically soft and chemically disordered A1 phase that may have two distinct domain structures. Above a critical thickness dcr30d_{cr}\sim 30 nm the presence of an out of plane anisotropy induces the formation of stripes, while for d<dcrd<d_{cr} planar domains occur. Magnetic interactions have been characterized using the well known DCD-IRM remanence protocols, δM\delta M plots, and magnetic viscosity measurements. We have observed a strong correlation between the domain configuration and the sign of the magnetic interactions. Planar domains are associated with positive exchange-like interactions, while stripe domains have a strong negative dipolar-like contribution. In this last case we have found a close correlation between the interaction parameter and the surface dipolar energy of the stripe domain structure. Using time dependent magnetic viscosity measurements, we have also estimated an average activation volume for magnetic reversal, Vac1.37×104\langle V_{ac}\rangle \sim 1.37\times 10^{4} nm3,^{3}, which is approximately independent of the film thickness or the stripe period.Comment: 25 pages, 11 figure

    Fractura-luxación posterior de hombro tratada mediante la técnica de McLaughlin

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    Se presenta un caso de luxación posterior de hombro, con fractura por impactación de la cabeza humeral, ocasionada por crisis convulsivas. Estas lesiones no son fáciles de reconocer en los primeros momentos, y en nuestro caso se precisó de un estudio radiográfico en distintas proyecciones y una TAC. Se realizó tratamiento quirúrgico mediante la técnica original de McLaughlin. A los 7 meses de la intervención el paciente ha recuperado casi totalmente la movilidad en dicho hombro y está libre de dolor.A case of posterior dislocation of the shoulder with locked fracture of the humeral head after a convulsive seizure is reported. At first stages, this type is very difficult to recognize. In our case, a radiographic study in different views and a CT-scan were needed. Surgical treatment were carried out according to McLauglin's original technique. Seven months after surgery the patient had regained almost complete range of shoulder motion and was pain-free
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