Non-adiabatic corrections to elastic scattering of halo nuclei

We derive the formalism for the leading order corrections to the adiabatic approximation to the scattering of composite projectiles. Assuming a two-body projectile of core plus loosely-bound valence particle and a model (the core recoil model) in which the interaction of the valence particle and the target can be neglected, we derive the non-adiabatic correction terms both exactly, using a partial wave analysis, and using the eikonal approximation. Along with the expected energy dependence of the corrections, there is also a strong dependence on the valence-to-core mass ratio and on the strength of the imaginary potential for the core-target interaction, which relates to absorption of the core in its scattering by the target. The strength and diffuseness of the core-target potential also determine the size of the corrections. The first order non-adiabatic corrections were found to be smaller than qualitative estimates would expect. The large absorption associated with the core-target interaction in such halo nuclei as Be11 kills off most of the non-adiabatic corrections. We give an improved estimate for the range of validity of the adiabatic approximation when the valence-target interaction is neglected, which includes the effect of core absorption. Some consideration was given to the validity of the eikonal approximation in our calculations.Comment: 14 pages with 10 figures, REVTeX4, AMS-LaTeX v2.13, submitted to Phys. Rev.

Matter radii of light halo nuclei

We re-examine the matter radii of diffuse halo nuclei, as deduced from reaction cross section measurements at high energy. Careful consideration is given to the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction. Using $^{11}$Li, $^{11}$Be and $^{8}$B as examples we show that data require significantly larger matter radii than previously reported. The revised value for $^{11}$Li of 3.55 fm is consistent with three-body models with significant $1s$-intruder state components, which reproduce experimental $^{9}$Li momentum distributions following $^{11}$Li breakup, but were hitherto thought to be at variance with cross section data.Comment: 8 pages RevTeX plus 5 Postscript figures. Figures also available at http://www.ph.surrey.ac.uk/scnp/jakpub/figures.html Scheduled tentatively for 13May96 issue of Phys. Rev. Let

The optical potential of 6^{6}He in the eikonal approximation

The new data of the elastic scattering of $^{6}$He+$^{12}$C at about 40 MeV/nucleon are analyzed in the eikonal approximation. The $^{6}$He+$^{12}$C phase-shift function is evaluated completely without any {\it ad hoc} assumption by a Monte Carlo integration, which makes it possible to use a realistic 6-nucleon wave function for a halo nucleus $^{6}$He. The effect of the breakup of $^6$He on the elastic differential cross sections as well as the optical potential is studied at different energies from 40 to 800 MeV/nucleon. PACS number(s): 24.10.-i; 21.60.Ka; 25.60.Bx; 25.10.+s Keywords: Eikonal; Glauber; Monte Carlo; Halo; BreakupComment: 13 pages, 9 figure

Waiting for the Revolution to End: Syrian displacement, time and subjectivity

Waiting for the Revolution to End explores the Syrian revolution through the experiences of citizens in exile. Based on more than three years of embedded fieldwork with Syrians displaced in the border city of Gaziantep (southern Turkey), the book places the Syrian revolution and its tragic aftermath under ethnographic scrutiny. It charts the evolution from peaceful uprising (2011) to armed confrontation (2012), descent into fully fledged conflict (2013) and finally to proxy war (2015), to propose an understanding of revolution beyond success and failure. While the Assad regime remains in place, the Syrian revolution (al-thawra) still holds a transformational power that can be located on intimate and world-making scales. Charlotte Al-Khalili traces the unintended consequences of revolution and its unexpected consequences to reveal the reshaping of Syrian life-worlds and exiles’ evolving theorizations, experiences and imaginations of al-thawra. She describes the in-between spatio-temporal realm inhabited by Syrians displaced to Turkey as they await the revolution’s outcomes, and maps the revolution’s multidimensional and multi-scalar effects on their everyday life. By following the chronology of events inside Syria and Syrians’ geography of displacement, the book makes the relation between revolution and displacement its centerpiece, both as an ethnographic object and an analytical device

FaCE: a tool for Three Body Faddeev calculations with core excitation

FaCE is a self contained programme, with namelist input, that solves the three body Faddeev equations. It enables the inclusion of excitation of one of the three bodies, whilst the other two remain inert. It is particularly useful for obtaining the binding energies and bound state structure compositions of light exotic nuclei treated as three-body systems, given the three effective two body interactions. A large variety of forms for these interactions may be defined, and supersymmetric transformations of these potentials may be calculated whenever two body states need to be removed due to Pauli blocking.Comment: 19 pg, 3 figs, program available for download from ftp://ftp.ph.surrey.ac.uk/pub/thompson/face

Production and Assessment of Usefulness of Interactive 2-D and Stereoscopic 3-D Videos as Tools for Anatomic Dissection Preparation and Examination Review

Laboratory is an integral part of a gross anatomy course in which students have their first in–depth dissection experience and explore structure-function relationships. Students arrive in the course that requires acquisition of a large vocabulary and visual imagery with scant prior knowledge. Even with extensive preparation on their part, the task is so difficult that students rely heavily on help from peers, teaching assistants, and instructors to gain the best from laboratory time. In recognition of the complexity of the learning task and the limitation on the amount of help available, this research was conducted to explore the value of educational tools that could enhance learning, make time in the laboratory more profitable, and decrease dependency on peers, teaching assistants, and instructors. Because anatomy is a highly visually based discipline, it was reasoned that interactive high definition videos with verbal descriptions of dissections would enhance the learning process. High definition videos of dissections were produced in 2–D and stereoscopic 3–D formats and compared with the standard dissection guide as tools for laboratory preparation. Stereoscopic 3–D format was included because of the hypothesis that the depth it provides might help students more readily grasp the relationships of structures to each other. Timing, duration, and tools provided to interact with the various formats varied with the experiment. The videos consisted of short presentations (10–14 minutes) of dissection steps or reviews of relationships of structures and were self–paced so they could be viewed more than once. Questions to encourage interaction with the materials were integrated into the videos and supplied with the Guide. Depending on the experiment, data collected included performance on paper and practical examinations, dissection quality, and frequency of requests for help in addition to surveys designed to assess ease of use and acceptance of the various presentation modes. Results presented in the thesis indicate that videos were superior to the guide in helping students prepare for dissection and develop understanding of the assigned body structures and their relationships. With the reservation that mode of 3–D delivery may play a role, 2–D videos were usually rated more positively than 3–D videos in student opinions. Both types of videos improved performance on various assessments and received more positive feedback when compared to the laboratory manual. This research confirmed the basic hypothesis that videos are effective tools for use in anatomy education and that they are worthy of significant investment of resources to help overcome some of the challenges facing anatomy educators

Linear Pigmented Purpuric Dermatoses

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