14,840 research outputs found
Proton emission induced by polarized photons
The proton emission induced by polarized photons is studied in the energy
range above the giant resonance region and below the pion emission threshold.
Results for the 12C, 16O and 40Ca nuclei are presented. The sensitivity of
various observables to final state interaction, meson exchange currents and
short range correlations is analyzed. We found relevant effects due to the
virtual excitation of the resonance.Comment: 12 pages, 11 figures, 1 tabl
Low-lying magnetic excitations of doubly-closed-shell nuclei and nucleon-nucleon effective interactions
We have studied the low lying magnetic spectra of 12C, 16O, 40Ca, 48Ca and
208Pb nuclei within the Random Phase Approximation (RPA) theory, finding that
the description of low-lying magnetic states of doubly-closed-shell nuclei
imposes severe constraints on the spin and tensor terms of the nucleon-nucleon
effective interaction. We have first made an investigation by using four
phenomenological effective interactions and we have obtained good agreement
with the experimental magnetic spectra, and, to a lesser extent, with the
electron scattering responses. Then we have made self-consistent RPA
calculations to test the validity of the finite-range D1 Gogny interaction. For
all the nuclei under study we have found that this interaction inverts the
energies of all the magnetic states forming isospin doublets.Comment: 19 pages, 13 figures, 7 tables, accepted for publication in Phys.
Rev.
Magnetic excitations in nuclei with neutron excess
The excitation of the , and modes in O, O,
O, O, Ca, Ca, Ca and Ca nuclei is
studied with self-consistent random phase approximation calculations.
Finite-range interactions of Gogny type, containing also tensor-isospin terms,
are used. We analyze the evolution of the magnetic resonances with the
increasing number of neutrons, the relevance of collective effects, the need of
a correct treatment of the continuum and the role of the tensor force.Comment: 18 pages, 12 figures, 2 tables, accepted for publication in Physical
Review
Effects of state dependent correlations on nucleon density and momentum distributions
The proton momentum and density distributions of closed shell nuclei are
calculated within a model treating short--range correlations up to first order
in the cluster expansion. The validity of the model is verified by comparing
the results obtained with purely scalar correlations with those produced by
finite nuclei Fermi Hypernetted Chain calculations. State dependent
correlations are used to calculate momentum and density distributions of 12C,
16O, 40Ca, and 48Ca, and the effects of their tensor components are studied.Comment: 16 pages, latex, 8 figures, accepted for publication in Phys. Rev.
Treatment of hepatic epithelioid hemangioendothelioma with liver transplantation
Ten patients received liver transplants for unresectable epithelioid hemangioendothelioma (EHE). At the time of transplantation, four patients had microscopic metastases to the hilar lymph nodes, and one of the four also had metastases to a rib. The fifth patient had metastases to the lung, pleura, and diaphragm. The remaining five patients were believed to be free of metastatic disease. Two of these five patients died of metastatic disease at 3 and 16 months, respectively, after transplantation. Interestingly, all five patients with metastatic involvement are currently alive 40.6 ± 22 months (mean ± standard error of mean [SEM]) after transplantation, although one of these patients currently has metastatic disease to the lungs and mediastinum. Thus, the projected 5âyear actuarial survival rate is 76%, with two patients at risk after the third year. In conclusion, liver transplantation is a reasonable procedure for bulky, otherwise unresectable, EHE even in the presence of metastatic disease. Copyright © 1988 American Cancer Societ
Short-range Correlations in a CBF description of closed-shell nuclei
The Correlated Basis Function theory (CBF) provides a theoretical framework
to treat on the same ground mean-field and short-range correlations. We
present, in this report, some recent results obtained using the CBF to describe
the ground state properties of finite nuclear systems. Furthermore we show some
results for the excited state obtained with a simplified model based on the CBF
theory.Comment: 10 latex pages plus 6 uuencoded figure
An automatic visual analysis system for tennis
This article presents a novel video analysis system for coaching tennis players of all levels, which uses computer vision algorithms to automatically edit and index tennis videos into meaningful annotations.
Existing tennis coaching software lacks the ability to automatically index a tennis match into key events, and therefore, a coach who uses existing software is burdened with time-consuming manual video editing. This work aims to explore the effectiveness of a system to automatically detect tennis events. A secondary aim of this work is to explore the bene- fits coaches experience in using an event retrieval system to retrieve the automatically indexed events. It was found that automatic event detection can significantly improve the experience of using video feedback as part of an instructional coaching session. In addition to the automatic detection of key tennis events, player and ball movements are automati- cally tracked throughout an entire match and this wealth of data allows users to find interesting patterns in play. Player and ball movement information are integrated with the automatically detected tennis events, and coaches can query the data to retrieve relevant key points during a match or analyse player patterns that need attention. This coaching software system allows coaches to build advanced queries, which cannot be facilitated with existing video coaching solutions, without tedious manual indexing. This article proves that the event detection algorithms in this work can detect the main events in tennis with an average precision and recall of 0.84 and 0.86, respectively, and can typically eliminate man- ual indexing of key tennis events
A Moonlight Meander / words by S. M. Roberts
Cover: drawing of an African American couple strolling through the moonlight; description reads characteristic march or two-step; Publisher: Eclipse Publishing Co. (Philadelphia)https://egrove.olemiss.edu/sharris_b/1003/thumbnail.jp
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