60 research outputs found

    Observation and Spectroscopy of New Proton-Unbound Isotopes 30Ar and 29Cl: An Interplay of Prompt Two-Proton and Sequential Decay

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    Previously unknown isotopes Ar30 and Cl29 have been identified by measurement of the trajectories of their in-flight decay products S28+p+p and S28+p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of Ar30 and Cl29 were found at 2.25+0.15−0.10 and 1.8±0.1  MeV above the two- and one-proton thresholds, respectively. The lowest states in Ar30 and Cl29 point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the Ar30 ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of Ar∗30(2+) has been obtained by detecting two decay branches into the ground and first-excited states of the S28 fragment.A. G., S. K., S. R., and P. S. were supported by the Helmholtz Association Grant No. IK-RU-002. L. V. G. was partly supported by the Ministry of Education and Science of the Russian Federation Grant No. NSh- 932.2014.2. A. F., A. G., L. V. G., S. K., P. S., and R. S. were partly supported by the Russian Foundation for Basic Research Grant No. 14-02-00090-a. This work was partly supported by the Polish National Science Center under Contract No. UMO-2011/01/B/ST2/01943. A. A. C. acknowledges support by the Polish Ministry of Science and Higher Education by Grant No. 0079/DIA/ 2014/43 (Grant Diamentowy). M. P. and X. X. are grateful for a support from the Helmholtz International Center for FAIR (HIC for FAIR). Y. L. was supported by the Helmholtz-CAS Joint Research Group Grant No. HCJRG- 108. J. M. E. acknowledges support from the FPA2009- 08848 contract (MICINN, Spain

    Precise measurement of near-barrier 8He+208Pb elastic scattering : comparison with 6He

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    Dramatic differences in the elastic scattering of the neutron rich nuclei 6He and 8He are found when new high quality data for the 8He+208Pb system are compared with previously published 6He+208Pb data at the same laboratory frame incident energy. The new 8He data are of the same level of detail as for stable beams. When comparing them with those previously obtained for 6He+208Pb at the same energy, it is possible to determine from the data alone that 6He has a much longer range absorption than 8He. However, both nuclei show significant absorption beyond their strong absorption radii. While it has been known for a long time that elastic scattering at energies around the barrier only determines the optical potential over a small distance in radial space, typically ±0.5 fm or so, both the 6He and the 8He imaginary potentials obtained from various optical model fits to these data are the same over a much wider range of ±1.5 fm.The authors would like to thank the staff of the GANIL accelerator facility for providing the high quality 8He beam. This work was supported in part by Grant No. FPA2010-22131-C02-01 (FINURA) and Grant No. FPA2013-47327-C2-1-R from the Spanish Ministry of Economy and Competitiveness, UNAM-PAPIIT IA101616 (Mexico), Grant No. N202 033637 from the Ministry of Science and Higher Education of Poland, and Contract No. EUI2009-04163 (EUROGENESIS) from the European Science Foundation

    Reaction Dynamics for the Systems 7Be,8B + 208Pb at Coulomb Barrier Energies

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    In this contribution we describe the first results obtained for the investigation of the elastic scattering process in the reactions induced by the Radioactive Ion Beams 7Be and 8B on a 208Pb target at Coulomb barrier energies. The experimental data were analyzed within the framework of the optical model in order to extract the total reaction cross section. The comparison with data available in literature for reactions induced on 208Pb by light ions in the mass range A = 6-8 shows that the loosely-bound 8B has the largest reactivity

    Interaction of 8He with 208Pb at near-barrier energies: 4He and 6He production

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    Angular distributions for the inclusive 4He and 6He production cross sections in the 8He+208Pb system at incident energies of 16 and 22 MeV measured at the SPIRAL facility of the GANIL laboratory are presented. Using a combination of kinematical arguments and distorted wave Born approximation (DWBA) calculations, neutron transfer reactions were inferred to be the dominant contributors to both inclusive cross sections. Model-dependent values for the ratios of two- to one-neutron stripping, s2n/s1n, were derived and compared with previous results for 8He and 6He projectiles incident on other heavy targets. Three- and four-neutron stripping were inferred to be the main processes leading to 4He production, although the exact mechanism remains to be elucidated.The authors would like to thank the staff of the GANIL accelerator facility for providing the high-quality 8He beam. This work was supported in part by Grants No. FPA-2010-22131-CO2-01 (FINURA) and No. FPA2013-47327-C2-1-R from the Spanish Ministry of Economy and Competitiveness, UNAM-PAPIIT IA103218 (Mexico); Grant No. N202 033637 from the Ministry of Science and Higher Education of Poland; the National Science Centre of Poland under Contracts No. 2013/08/M/ST2/00257 (LEA-COPIGAL) and No. 2014/14/M/ST2/00738 (COPIN-INFN Collaboration); and Grant No. EUI2009-04163432 (EUROGENESIS) from the European Science Foundation

    Valoración económico-ambiental de recursos naturales seleccionados en la cuenca del río Guanabo, La Habana, Cuba

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    En el estudio se identifican las principales funciones ambientales asociadas a recursos naturales degradados en sectores seleccionados de la cuenca del río Guanabo, ubicada en La Habana, Cuba. Parte de estas funciones se valoran económicamente y se ofrecen criterios para un mejor aprovechamiento de dichos recursos, teniendo en cuenta su valor económico total.In this research, the main environmental functions associated to degraded natural resources in selected sites of the Guanabo river basin, located in Havana, were identified. Some of these functions were valued in economic terms and guidance criteria were offered to improve management and use of the studied resources based on their estimated total economic value

    Análisis jurídico de la interferencia de las comunicaciones en la periferia de los centros de cumplimiento de pena

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    El impacto de la afectación de los bloqueadores de señal telefónica sobre la población aledaña a dichos Centros de Cumplimientos de Penas, en sus vidas diarias, si dicha medida extraordinaria conlleva ventajas y a la vez desventajas para la población dentro de nuestra investigación desglosaremos aspectos para conocer la verdad que plantea el Gobierno de El Salvador como una medida para solucionar los crímenes dentro de los Centros de Cumplimientos de Pena

    Procurement and characterization of cellulose nanocrystals from cassava bagasse (Manihot esculenta Crantz)

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    ABSTRACT Objective: Obtaining and characterizing cellulose nanocrystals from cassava bagasse. Design/methodology/approach: Cellulose nanocrystals were obtained from cassava bagasse by acid hydrolysis (HCI), ultrasonication, centrifugation, dialysis, deep freezing and lyophilization. The cassava bagasse and the cellulose nanocrystals obtained were physiochemically characterized by Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy with Coupled Elemental Analysis (SEM-EDS). As an additional technique, Atomic Force Microscopy (AFM) was used. Results: The analyzes performed show that the cellulose obtained was type Iβ. This study reports a percentage of crystallinity of cassava bagasse cellulose of 37.1%, increasing the percentage to 48% of crystallinity in cellulose nanocrystals. The diameters of the cassava bagasse fibers were reported to be 2 μm and their elemental composition (SEM-EDS) mainly constituted by carbon (C), oxygen (O) and traces of (N). The morphology observed through AFM of the nanocrystals of cassava bagasse (Manihot esculenta) was rod-shaped, with a helical appearance without residual charge, with diameters between 8.7 and 9.3 nm. Limitations on study/implications: The acid hydrolysis process showed a low percentage of crystallinity, although higher than other works reported for cassava bagasse. Findings/conclusions: The results obtained show the possibility of obtaining cellulose nanocrystals from cassava bagasse ().    Objective: To procure and characterize cellulose nanocrystals from cassava bagasse. Design/methodology/approach: Cellulose nanocrystals were obtained from cassava bagasse by acid hydrolysis (HCI), ultrasonication, centrifugation, dialysis, deep freezing and lyophilization. The cassava bagasse and the cellulose nanocrystals obtained were physicochemically characterized by Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy with Coupled Elemental Analysis (SEM-EDS). As an additional technique, Atomic Force Microscopy (AFM) was used. Results: The analyses performed show that the cellulose obtained was type Iβ. This study reports a percentage of crystallinity of the cassava bagasse cellulose of 37.1%, increasing the percentage to 48% crystallinity in cellulose nanocrystals. The diameters of the cassava bagasse fibers were reported to be 2 μm and their elemental composition (SEM-EDS) mainly constituted by carbon (C), oxygen (O) and traces of nitrogen (N). The morphology observed through AFM of the nanocrystals of cassava bagasse (Manihot esculenta) was rod-shaped, with helicoidal appearance without residual charge, with diameters between 8.7 and 9.3 nm. Limitations on study/implications: The acid hydrolysis process showed a low percentage of crystallinity, although higher than other works reported for cassava bagasse. Findings/conclusions: The results obtained confirm the possibility of obtaining cellulose nanocrystals from cassava bagasse (Manihot esculenta)

    La mentoría en la Escuela Universitaria Politécnica de la Universidad de Sevilla

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    XVIII Congreso Universitario de Innovación Educativa en las Enseñanzas Técnicas. Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación. Universidad de Cantabria : Santander, 6 a 9 de julio de 2010Con el fin de integrar a los alumnos de nuevo ingreso, la Escuela Universitaria Politécnica de la Universidad de Sevilla ha puesto en marcha en el curso 2008-09 un Plan de Acción Tutorial (EUPAT) basado en una red en la que participan el profesorado tutor, alumnado mentor y alumnado tutorizado. En el presente trabajo se resumirá el proceso de formación del alumnado mentor y el trabajo desarrollado por el mismo dentro del Plan de Acción Tutorial. Así mismo, se analizarán las dificultades encontradas durante el transcurso de su formación y realización de la labor de mentoría y el nivel de satisfacción alcanzado. Finalmente, se hará una reflexión sobre las debilidades y los puntos de mejora que se pueden deducir del desarrollo hasta el momento de esta acción tutorialIn order to integrate new students, the Polytechnic School of the University of Seville has launched in the year 2008-09 an Tutorial Action Plan (EUPAT) based on a network involving teachers, mentor students and tutored students. In this paper we resume the formation of mentor students and work developed by the same within the Tutorial Action Plan. Also, analyzing the difficulties encountered during the course of their training and carrying out the work of mentoring and the satisfaction level achieved. Finally, we will reflect on the weaknesses and areas for improvement that can be deducted from the development until the time of this action tutorial

    Experiencias de Innovación docente en los Estudios Jurídicos: una visión práctica

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    Esta publicación se enmarca dentro de las actividades del Grupo de Investigación de la Universidad de Extremadura Fiscalitas & Iuris.Este trabajo surge con el objetivo principal de dar visibilidad y publicidad a las nuevas técnicas docentes en el seno de la Facultad de Derecho de la UEx. Como se sabe, se ha producido un innegable y significativo avance en el uso de nuevas técnicas docentes y también de las TICs aplicadas a la docencia en la Facultad de Derecho, no obstante, aún es necesario profundizar en el uso de las mismas y extenderlas entre todos los miembros del claustro de profesores, y fundamentalmente entre aquellos que llevan más años ejerciendo la docencia a través de la colaboración y la coordinación con los profesores noveles, que son quienes principalmente se sirven en mayor medida de tales instrumentos docentes. De otra parte, también era necesario que los docentes más experimentados pudieran encontrar un foro en el que transmitir y compartir con los noveles cuales son las técnicas e instrumentos docentes que ellos han venido utilizando durante el ejercicio de su magisterio, de modo que, en el marco de una relación sinalagmática, se produjera una interacción entre uno u otro grupo de docentes, a fin de fomentar el necesario debate y el intercambio de experiencias e instrumentos docentes, y en su caso el desarrollo y perfeccionamiento de los mismos; algo que hemos pretendido realizar con este trabajo, y que en buena medida hemos logrado. Las finalidades y objetivos concretos que perseguíamos, en atención a la situación expuesta eran fundamentalmente tres: • En primer lugar, la implementación de un proyecto de innovación docente integrado por una diversidad de actividades coordinadas, cada uno de ellas bajo la directa coordinación de un profesor o profesora de la UEx, aplicado a una o varias asignaturas impartidas en la Facultad de Derecho. • En segundo lugar, el establecimiento en la Facultad de Derecho de un foro de coordinación e intercambio de buenas prácticas docentes sobre la base de cada uno de las actividades coordinadas, en el que pudieran participar profesores noveles y veteranos. Para ello se desarrolló espacio virtual de innovación docente en estudios jurídicos, a través del Campus Virtual de la UEx, en el que los Profesores noveles y veteranos pudieron y puede compartir recursos e informaciones sobre prácticas de innovación. • Y, en tercer lugar, la difusión y consolidación de instrumentos de innovación docente directamente aplicadas a la docencia de los estudios jurídicos, mediante la transferencia de los resultados y la publicación de los mismos; a fin de que esta transferencia sirva de base a futuras profundizaciones en el campo de la innovación docente en los estudios jurídicos.Proyecto “Desarrollo, profundización e intercambio de buenas prácticas de innovación docente en la Facultad de Derecho” (UEx 2015-2016

    Reexamination of 6Li + p elastic scattering in inverse kinematics

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    Elastic-scattering measurements have been performed for the Li6+p system in inverse kinematics at the energies of 16, 20, 25, and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud in Catania, Italy. The results are considered in a Jeukenne-Lejeune-Mahaux and a continuum discretized coupled-channel calculation framework
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