38,832 research outputs found

    Search for α\alpha-cluster states in even-even Cr isotopes

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    The α+core\alpha + \mathrm{core} structure is investigated in even-even Cr isotopes from the viewpoint of the local potential model. The comparison of Qα/AQ_{\alpha}/A values for even-even Cr isotopes and even-even A=46,54,56,58A = 46,54,56,58 isobars indicates that 46^{46}Cr and 54^{54}Cr are the most favorable even-even Cr isotopes for α\alpha-clustering. The ground state bands of the two Cr isotopes are calculated through a local α+core\alpha + \mathrm{core} potential with two variable parameters. The calculated spectra give a very good description of most experimental 46^{46}Cr and 54^{54}Cr levels. The reduced α\alpha -widths, rms intercluster separations and B(E2)B(E2) transition rates are determined for the ground state bands. The calculations reproduce the order of magnitude of the available experimental B(E2)B(E2) values without using effective charges and indicate that the first members of the ground state bands present a stronger α\alpha-cluster character. The volume integral per nucleon pair and rms radius obtained for the α+50\alpha+^{50}Ti potential are consistent with those reported previously in the analysis of α\alpha elastic scattering on 50^{50}Ti

    Predicting outcome in acute low back pain using different models of patient profiling

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    Study Design: Prospective observational study of prognostic indicators, utilising data from a randomised, controlled trial of physiotherapy care of acute low back pain (ALBP) with follow up at 6 weeks, 3 months and 6 months. Objective: To evaluate which patient profile offers the most useful guide to long-term outcome in ALBP. Summary of Background Data: The evidence used to inform prognostic decision-making is derived largely from studies where baseline data is used to predict future status. Clinicians often see patients on multiple occasions so may profile patients in a variety of ways. It is worth considering if better prognostic decisions can be made from alternative profiles. Methods: Clinical, psychological and demographic data were collected from a sample of 54 ALBP patients. Three clinical profiles were developed from information collected at baseline, information collected at 6 weeks, and the change in status between these two time points. A series of regression models were used to determine the independent and relative contributions of these profiles to the prediction of chronic pain and disability. Results: The baseline profile predicted long-term pain only. The 6-week profile predicted both long-term pain and disability. The change profile only predicted long-term disability (p \u3c 0.01). When predicting long-term pain, after the baseline profile had been added to the model, the 6-week profile did not add significantly when forced in at the second step (p \u3e 0.05). A similar result was obtained when the order of entry was reversed. When predicting long-term disability, after the 6-week profile was entered at the first step, the change profile was not significant when forced in at the second step. However, when the change profile was entered at the first step and the 6-week clinical profile was forced in at the second step, a significant contribution of the 6-week profile was found. Conclusions: The profile derived from information collected at 6 weeks provided the best guide to long-term pain and disability. The baseline profile and change in status offered less predictive value
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