Puzzle of Complete Fusion Suppression in Weakly Bound Nuclei: A Trojan Horse Effect?

Experimental studies of nuclear collisions involving light weakly bound nuclei show a systematic suppression of the complete fusion cross section by ∼30% with respect to the expectation for tightly bound nuclei, at energies above the Coulomb barrier. Although it is widely accepted that the phenomenon is related to the weak binding of these nuclei, the origin of this suppression is not fully understood. Here, we present a novel approach that provides the complete fusion for weakly bound nuclei and relates its suppression to the competition between the different mechanisms contributing to the reaction cross section. The method is applied to the 6,7Li+209Bi reactions, where we find that the suppression of complete fusion is mostly caused by the flux associated with nonelastic breakup modes, such as the partial capture of the projectile (incomplete fusion), whereas the elastic breakup mode is found to play a minor role. Finally, we demonstrate that the large α yields observed in these reactions can be naturally explained as a consequence of a Trojan Horse mechanism.National Science Foundation under Contract No. NSF-PHY-1520972 with Ohio UniversityMinisterio de Ciencia,Innovación y Universidades (Projects No. FIS2014-53448-C2-1-P and No. FIS2017-88410-P)European Union’s Horizon 2020 (Grant Agreement No. 654002

A proof of slow-roll local decay of inflaton fields in cosmology and axion fields in cold dark matter models

We consider the long time behavior of solutions to scalar field models appearing in the theory of cosmological inflation (oscillons) and cold dark matter, in presence or absence of the cosmological constant. These models are not included in standard mathematical literature due to their unusual nonlinearities, which model different features to classical ones. Here we prove that these models fit in the theory of dispersive decay by computing new virials adapted to their setting. Several important examples, candidates to model both effects are studied in detail

Focused verbal inflections in Spanish

Spanish allows to focus the Number and Person features of the verbal inflection to produce an interpretation similar to that of a contrastively focused pronoun. This squib discusses two properties distinguishing both phenomena

Pueblos indígenas, VIH y políticas públicas en Latinoamérica: una exploración en el panorama actual de la prevalencia epidemiológica, la prevención, la atención y el seguimiento oportuno

Este artículo describe y analiza la situación epidemiológica, de prevención, atención y tratamiento del VIH para pueblos indígenas en Latinoamérica. Se identificaron, clasificaron y analizaron 304 materiales publicados, entre ellos, declaraciones, protocolos de políticas públicas y programas en salud, estudios de caso y revisiones del estado del arte locales, nacionales y regionales. La vulnerabilidad social diferencial en la adquisición del VIH y la inequidad en el acceso a la atención de la población indígena en Latinoamérica, con respecto a otras, se debe a la yuxtaposición de factores como la violencia estructural, el género, el racismo, la discriminación por la condición de salud en el caso de las personas que viven con VIH y la posición subordinada que, en general, ocupan en sociedades estratificadas en función de esquemas sociales y económicos pero también étnicos y culturales. Los escasos estudios desagregados por etnicidad sobre prevalencia epidemiológica y morbimortalidad existentes revelan datos desalentadores y alertan sobre la necesidad de conocer el comportamiento de la epidemia en esta población y abordar sus repercusiones en términos preventivos, de atención y seguimiento oportuno.This article aims to describe and analyze the situations of epidemiological prevalence, prevention, care and treatment of HIV in indigenous populations of Latin America. In order to do so, 304 published materials – including declarations, public policy and health program protocols, case studies and literature reviews with local, national and regional scopes – were identified, classified and analyzed. The differential social vulnerability to HIV infection and the inequity in health care access among indigenous populations can be attributed to the juxtaposition of factors such as structural violence, gender, racism, and discrimination due health condition (living with HIV) as well as the subordinated position of indigenous peoples in societies stratified not only socially and economically but also ethnically and culturally. The few studies done in the region on epidemiological prevalence, morbidity and mortality that are disaggregated by ethnicity reveal alarming data highlighting the need for further information on the epidemic in this population so as to address its repercussions in terms of prevention, care and timely follow-up

Evaluation of inclusive breakup cross sections in reactions induced by weakly-bound nuclei within a three-body model

In 1980s Ichimura, Austern and Vincent [Phys.Rev.C 32, 431 (1985)] proposed a quantum mechanical theory to study the problem of inclusive breakup cross sections in the nuclear reactions. Using the DWBA version of this model, applications to deuteron and 6 Li inclu- sive breakup reactions are presented and compared with some available dataMinisterio Español de Economía y Competitividad (FIS2013-41994-P)Junta de Andalucía (FQM160, P07-FQM-02894

Core excitation effects in the breakup of the one-neutron halo nucleus 11Be on a proton target

We investigate the phenomenon of core excitation in the inelastic and breakup of two-body halo nuclei, composed by a valence nucleon and a core. To evaluate the importance of this effect we propose a simple reaction model based on an extension of the standard distorted wave Born approximation (DWBA) method. The model takes into account core-excited admixtures in the states of the composite projectile, as well as the possibility of dynamic core excitation due to the interaction of the core with the target. As an application of the model, we present calculations for the breakup of 11Be on a proton target at an incident energy of 63.7 MeV/nucleon, comparing it with the available data for this reaction. We find that the data are well reproduced by the model and that the effect of dynamic core excitation is essential to explain the observed cross section.Ministerio de Ciencia e Innovación (España) FPA2009-07653Programa Consolider-Ingenio 2010 CSD2007-0004

Numerical assessment of post-prior equivalence for inclusive breakup reactions

We address the problem of the post-prior equivalence in inclusive breakup reactions induced by weakly bound nuclei. The problem is studied within the distorted-wave Born approximation (DWBA) model of Ichimura, Austern, and Vincent [ Phys. Rev. C 32 , 431 ( 1985 )]. The post and prior formulas obtained in this model are briefly recalled and applied to several breakup reactions induced by deuterons and 6 Li projectiles, to test their actual numerical equivalence. The different contributions of the prior-form formula are also discussed. A critical comparison with the prior-form DWBA model of Udagawa and Tamura [ Phys.Rev.C 24 , 1348 ( 1981 )] is also providedMinisterio de Economía y Competitividad (España) FIS2013-41994-PPrograma Consolider-Ingenio CPAN CSD2007-00042Junta de Andalucía FQM160 P07-FQM-0289

Improved deuteron elastic breakup energy dependence via the continuum-discretized coupled-channels method

Experimental elastic-scattering angular distributions for deuteron interaction with 63Cu and 93Nb targets are compared with calculations performed within the continuum-discretized coupled-channels (CDCC) method, in which coupling to breakup channels is explicitly taken into account. The calculated elastic breakup cross sections are compared with the predictions of an empirical parametrization for a wide range of deuteron incident energies. The good agreement between the calculations and the systematics at the energies where data are available indicates that the CDCC method permits a useful assessment of empirical parametrizations and provides useful guidance for the extrapolation of these parametrizations beyond the energies formerly considered.CNCSIS PNII-IDEI-43/2008Ministerio de Ciencia e Innovación (España) FPA2009-07653Programa Consolider-Ingenio 2010 CSD2007-0004

Reexamining closed-form formulae for inclusive breakup: Application to deuteron- and 6 Li-induced reactions

The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the post-form theory proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)PRVCAN0556-281310.1103/PhysRevC.32.431] is revisited, and an alternative derivation of the nonelastic breakup part of the inclusive breakup is presented, making use of the coupled-channels optical theorem. Using the distorted-wave Born approximation (DWBA) version of this model, several applications to deuteron and Li6 reactions are presented and compared with available data. The validity of the zero-range approximation of the DWBA formula is also investigated by comparing zero-range with full finite-range calculationsMinisterio de Economía y Competitividad (España) FIS2013-41994-PJunta de Andalucía FQM160 P07-FQM-02894Programa Consolider-Ingenio 2010 (España) CSD2007-0004

Incidencia de gustos musicales compartidos en la formación de grupos de pares al interior del aula : un estudio de caso de alumnos de 8° año básica B del Colegio El Patrocinio de San José

Tesis (Profesor de Educación Musical para la Educación Preescolar y Básica, Licenciado en Educación)Pensando en el marco educativo en el cual los investigadores del presente estudio se desenvolverán como futuros profesores de música, se torna necesario el conocimiento de nuestros alumnos para generar una cercanía con ellos que propicie y favorezca el proceso de aprendizaje, bajo esta premisa el presente estudio se enfoca principalmente en reconocer los estilos musicales que son de preferencia de un grupo específico de alumnos de 8°básico pertenecientes al colegio El Patrocinio de San José, y cómo éstos pudieran incidir en diversos áreas del comportamiento mostrado por el grupo adolescente, de su forma de ser y la forma de relacionarse entre ellos. Bajo una perspectiva constructivista conoceremos algunos ámbitos de la realidad de este curso, el cual pertenece al colegio El Patrocinio de San José, ya que se describe el lugar de estudio y los sujetos estudiados tal como son en la realidad y no como se espera que sean (Hernández et al, 2006) ; además el análisis de la información recabada así como las conclusiones finales se definen y edifican a partir del conocimiento construido en el proceso de este estudio, tanto por parte de los investigadores como de los sujetos de estudio. Así, a partir de dos instrumentos de recolección de datos, se busca observar y comprender los aspectos que más definen y caracterizan a los adolescentes estudiados, en relación a sus intereses, formas de comportarse y cómo influye el ser parte o no de algún subgrupo social al interior del aula, principalmente en relación a las preferencias musicales. Mientras que como principal resultado de esta investigación se destacan las reflexiones que dicho proceso ha otorgado a los investigadores en pro de acercarse a conocer la realidad de un grupo de jóvenes que bien el día de mañana podrían representar un grupo de alumnos; así como la importancia de lograr entender que el cuerpo docente y paradocente debe ser consciente de los aspectos integrales que deben conocerse y desarrollarse, pensando en el ámbito académico y personal de los alumnos.Thinking on the educational frame in which the investigators of the present study will develop as future music teachers, it is absolutely necessary the knowledge of our pupils in order to generate a closeness with them that propitiates and strengthens the learning process. Under this premise the present study focuses principally in recognizing the musical styles which are of the preference of an specifical group of pupils of the 8th basic school and how these styles could incide in the diverse areas of the behaviour shown by the adolescent group, about their way of being and the way of relating among them. Under a constructivist prospect we will learn about certain contours of the reality of this class, that belongs to the El Patrocinio de San José School, since in it the place of the study and the studied subjects are described such as they are indeed and not as they are extected to be /Hernández et al., 2006); besides the analysis of the obtained information as well as the final conclusions are defined and built from the knowledge constructed in the process of this study both by the investigators and the study subjects. So, based on two data collection instruments, it is looked for observing and understanding the aspects that better define and characterize the studied adolescents, in relation to their interests, ways of behaving, and how being part or not being part of a certain social subgroup within the classroom has an influence, principally in relation to the musical preferences. So, as the main result of this investigation, it is stood out the reflections that the process has given to the investigators in order to come close to the reality of a group of young people that perfectly tomorrow represent a pupils group; as well as the importance of reaching the understanding that the teachers and teaching assistants staff must be conscious of the integral aspects that have to be known and developed, thinking on the pupils academic and personal environment