866 research outputs found

    Reactions of a Be-10 beam on proton and deuteron targets

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    The extraction of detailed nuclear structure information from transfer reactions requires reliable, well-normalized data as well as optical potentials and a theoretical framework demonstrated to work well in the relevant mass and beam energy ranges. It is rare that the theoretical ingredients can be tested well for exotic nuclei owing to the paucity of data. The halo nucleus Be-11 has been examined through the 10Be(d,p) reaction in inverse kinematics at equivalent deuteron energies of 12,15,18, and 21.4 MeV. Elastic scattering of Be-10 on protons was used to select optical potentials for the analysis of the transfer data. Additionally, data from the elastic and inelastic scattering of Be-10 on deuterons was used to fit optical potentials at the four measured energies. Transfers to the two bound states and the first resonance in Be-11 were analyzed using the Finite Range ADiabatic Wave Approximation (FR-ADWA). Consistent values of the spectroscopic factor of both the ground and first excited states were extracted from the four measurements, with average values of 0.71(5) and 0.62(4) respectively. The calculations for transfer to the first resonance were found to be sensitive to the size of the energy bin used and therefore could not be used to extract a spectroscopic factor.Comment: 16 Pages, 10 figure

    First observation of 54Zn and its decay by two-proton emission

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    The nucleus 54Zn has been observed for the first time in an experiment at the SISSI/LISE3 facility of GANIL in the quasi-fragmentation of a 58Ni beam at 74.5 MeV/nucleon in a natNi target. The fragments were analysed by means of the ALPHA-LISE3 separator and implanted in a silicon-strip detector where correlations in space and time between implantation and subsequent decay events allowed us to generate almost background free decay spectra for about 25 different nuclei at the same time. Eight 54Zn implantation events were observed. From the correlated decay events, the half-life of 54Zn is determined to be 3.2 +1.8/-0.8 ms. Seven of the eight implantations are followed by two-proton emission with a decay energy of 1.48(2) MeV. The decay energy and the partial half-life are compared to model predictions and allow for a test of these two-proton decay models.Comment: 4 pages, 4 figures, accepted for publication in PR

    Recent direct reaction experimental studies with radioactive tin beams

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    Direct reaction techniques are powerful tools to study the single-particle nature of nuclei. Performing direct reactions on short-lived nuclei requires radioactive ion beams produced either via fragmentation or the Isotope Separation OnLine (ISOL) method. Some of the most interesting regions to study with direct reactions are close to the magic numbers where changes in shell structure can be tracked. These changes can impact the final abundances of explosive nucleosynthesis. The structure of the chain of tin isotopes is strongly influenced by the Z=50 proton shell closure, as well as the neutron shell closures lying in the neutron-rich, N=82, and neutron-deficient, N=50, regions. Here we present two examples of direct reactions on exotic tin isotopes. The first uses a one-neutron transfer reaction and a low-energy reaccelerated ISOL beam to study states in 131Sn from across the N=82 shell closure. The second example utilizes a one-neutron knockout reaction on fragmentation beams of neutron-deficient 106,108Sn. In both cases, measurements of gamma rays in coincidence with charged particles proved to be invaluable.Comment: 11 pages, 5 figures, Zakopane Conference on Nuclear Physics "Extremes of the Nuclear Landscape", Zakopane, Poland, August 31 - September 7, 201

    Editorial of Special Issue of National Identities: Alevism as an ethno-religious identity: Contested boundaries

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    No abstract for editorial but this is the opening paragraph: This special issue on Alevism and trans/national Alevi identity critically engages with the relationship between religion, ethnicity and national identity. The core issues are as follows: • how ethnicity and religion are conceptualised for a relatively invisible ethnic group in different national contexts; • how religion and ethnicity intersect when Alevism is both a faith and an ethnic identity, especially when conceptions of that identity are contested; • how identity is shaped through state policies within different national policy contexts and how etic definitions of minority communities are constructed by the state or other agencies with the power to impose them on the community in contrast to the emic or self-definitions of Aleviness from within the Alevi community; • how despite the fragmented, heterogeneous nature of Alevi communities, there is also a sense of a single, transnational imaginary community, at least for the purposes of political assimilation/integration and activism; • how education and other arenas of political, religious and cultural engagement at local, national and transnational levels create the possibilities, both positively and negatively, for future action/policy to situate minority ethnic communities

    The current state of hospital-based emergency medicine in Germany

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    Germany has a long tradition of having physicians, often anesthesiologists with additional training in emergency medicine, deliver prehospital emergency care. Hospital-based emergency medicine in Germany also differs significantly from the Anglo-American model, and until recently having separate emergency rooms for different departments was the norm. In the past decade, many hospitals have created “centralized emergency departments” [Zentrale Notaufnahme (ZNAs)]. There is ongoing debate about the training and certification of physicians working in the ZNAs and whether Germany will adopt a specialty board certification for emergency medicine

    Retroviral DNA Integration: Viral and Cellular Determinants of Target-Site Selection

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    Retroviruses differ in their preferences for sites for viral DNA integration in the chromosomes of infected cells. Human immunodeficiency virus (HIV) integrates preferentially within active transcription units, whereas murine leukemia virus (MLV) integrates preferentially near transcription start sites and CpG islands. We investigated the viral determinants of integration-site selection using HIV chimeras with MLV genes substituted for their HIV counterparts. We found that transferring the MLV integrase (IN) coding region into HIV (to make HIVmIN) caused the hybrid to integrate with a specificity close to that of MLV. Addition of MLV gag (to make HIVmGagmIN) further increased the similarity of target-site selection to that of MLV. A chimeric virus with MLV Gag only (HIVmGag) displayed targeting preferences different from that of both HIV and MLV, further implicating Gag proteins in targeting as well as IN. We also report a genome-wide analysis indicating that MLV, but not HIV, favors integration near DNase I–hypersensitive sites (i.e., +/− 1 kb), and that HIVmIN and HIVmGagmIN also favored integration near these features. These findings reveal that IN is the principal viral determinant of integration specificity; they also reveal a new role for Gag-derived proteins, and strengthen models for integration targeting based on tethering of viral IN proteins to host proteins

    ¿Qué hay de política en la filosofía?: ocho ensayos

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    Pocos otros temas despiertan más polémicas que el de los vínculos entre filosofía y política: que quienes se dedican a la filosofía no deben verse influenciados por la política, que si a la política le corresponde ser auxiliada por la filosofía, que si el saber filosófico tiene que desligarse de las posiciones políticas, que si a las instituciones académicas de las humanidades les conviene independizarse del poder de turno, etc. Todas estas son discusiones que heredamos (no sin reformularlas y, por lo tanto, retransformarlas) desde la Antigüedad, en la que ya aparecería, de la mano de Platón, la figura del rey filósofo. Este libro reúne una variedad de abordajes que atraviesan debates sobre juicios de hecho y de valor, sobre la democra-cia como forma de gobierno y sobre la intervención de la historia en el vínculo de la filosofía y la política. Recuperando el pensamiento antiguo y moderno, pero concentrándose en la obra de intelectuales contemporáneos, los autores ponen en movimiento dilucidaciones de grandes como Max Weber, Jacques Rancière, Louis Althusser, Philippe Lacoue-Labarthe y Leo Strauss, entre otros. Así, ofrecen aquí un vívido panorama de las controversias que habitan los entrecruzamientos entre filosofía y política, coronando el volumen con la traducción de un texto de Claude Lefort, hasta el momento inédito en español

    Bricoleurs Extraordinaire: Sports Coaches in Inter War Britain

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    In Inter War Britain, individuals exploited their athletic skills by pursuing professional careers, or adopting amateur roles, as instructors, trainers and coaches, invariably drawing from, and elaborating on, existing practices. The coach was the master of a body of specialist craft knowledge, the tacit nature of which was transmitted through ‘stealing with the eyes’ as the apprentice watched the master in action (Gamble, 2001). Professional coaches saw themselves as practical men whose experiential knowledge concerning diet, physiological and psychological preparation, stimulants, massaging, medical treatments, talent identification, and so on provided critical components in their coaching ‘toolbox’ (Nelson, 1924, 25-26). Craft knowledge was never static. Coaching expertise is a fluid, cyclical process with practitioners continuously redeveloping their competencies (Turner, Nelson and Potrac, 2012, 323), and part of traditional craft expertise was the ability to react positively to shifting circumstances. Coaches were constantly stimulated to experiment by competitors, commercialisation, and emerging technologies (Clegg, 1977, 244), and they exemplified the notion of the ‘Bricoleur’ in constantly trialling emerging knowledge, intuitively accepting or rejecting appropriate material. This paper explores the ways in which practitioners developed their coaching ‘toolbox’ in Inter War Britain by drawing on examples from newspaper reports, personal and public archives, and instructional texts (eg. Tilden, 1920; Gent, 1922; Nelson, 1924; Mussabini, 1926; Lowe and Porritt, 1929; Abrahams and Abrahams, 1936). The author highlights the range of knowledge that coaches had at their command, well before the emergence of sports science and coaching certification programmes, and questions assumptions that coaches can no longer rely solely on ‘learning the trade’ through experience (Evans and Light, 2007). As Winchester et al. (2013) have emphasised, knowledge, skills, attitudes, and insights are developed from daily experiences in sport, work and at home, as well as through exposure to the coaching environment, and contemporary coaches still employ a largely implicit form of knowledge, closely connected to past experiences, which shares similarities with Inter War craft knowledge (Smith and Cushion, 2006, 363; Jones, Armour and Potrac, 2003), while identifying experimentation and experience as key reference points (Irwin, Hanton and Kerwin, 2004, 436, 439; Potrac, Jones and Cushion, 2007)
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