We study polarons in the one-dimensional Bond-Peierls electron-phonon model which phonons on bonds of a lattice modulate hopping electrons between sites and contrast results to those known for breathing-mode Peierls problem. By inspecting atomic limit, we show that polaronic dressing mass enhancement depend momentum dependence phonons. For dispersionless phonons, are perfectly localized unlike ...

We have calculated the effect of the inclusion of final state interactions on pion production from nuclei with incident pion beams. We find that the effect of absorption , along with geometric considerations, explains much of the enhancement at low invariant mass seen in recent data for invariant mass spectra with increasing atomic number. While the variation among nuclei is well reproduced for...

Computed tomography (CT) of the brain has been used extensively to evaluate both supraand infratentorial mass lesions . However, even with the use of intravenous contrast enhancement, visualization of small brainstem lesions has not been totally satisfactory . The differentiation of intrafrom extraaxial lesions has also at times proved difficult and frustrating. Computed tomography combined wit...