Distributed sources are included in the Einstein equations. Such modification of the general relativity provides a simple description of the accelerated expansion of the Universe with a dynamical scaling. Distributed sources can also be applied to more local cosmological phenomena, which defy conventional explanation. A possibility of superluminary effects is indicated. The Einstein equations f...

From the Department of Pathology, Chil­ dren’s Hospital, and Harvard Medical School — both in Boston (H.C.K.); and the Department of Pediatrics, Washing­ ton University School of Medicine, St. Louis (B.T.T.). Address reprint requests to Dr. Kinney at the Department of Pathol­ ogy, Enders Bldg. 1112, Children’s Hospi­ tal Boston, 300 Longwood Ave., Boston, MA 02115, or at hannah.kinney@childrens...

In this chapter we explain constructive methods for computing the cohomol-ogy of a sheaf on a projective variety. We also give a construction for the Beilinson monad, a tool for studying the sheaf from partial knowledge of its cohomology. Finally, we give some examples illustrating the use of the Beilinson monad.

We investigate a discrete-time Chen system. First, we give the topological classifications of fixed points this Then, analytically show that discrete system underlies Neimark–Sacker (NS) bifurcation and period doubling (PD) under specific parametric circumstances. confirm existence PD NS via explicit PD-NS criterion determine direction both bifurcations with help center manifold theory. perform...

We use lattice QCD to investigate some topics in strong interaction phenomenol-ogy which are usually related to soft pomeron exchange. These include hadronic cross-sections at high energies and diffractive scattering at HERA. Some numerical results are presented in the framework of the Landshoff-Nachtmann pomeron model, and strategies for further studies are discussed.

ogy, Head and Neck Surgery (G.S.W., R.E.H.), Hospital of the University of Pennsylvania, 3400 Spruce St. Philadelphia, PA 19104; and Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, Pa (V.M.R.). From the 1993 RSNA scientific assembly. Received January 31, 1994; revision requested March 14; revision received April 12; accepted April 19. Address reprint requests to D.M...

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— We review the role of massive neutrinos in astrophysics and cosmol-ogy, assuming that the oscillation interpretation of solar and atmospheric neutrinos is correct. In particular, we discuss cosmological mass limits, neutrino flavor oscillations in the early universe, leptogenesis, and neutrinos in core-collapse supernovae.

We prove that the lower bounds for Betti numbers of the rack, quandle and degeneracy cohomol-ogy given in [CJKS] are in fact equalities. We compute as well the Betti numbers of the twisted cohomology introduced in [CES]. We also give a group-theoretical interpretation of the second cohomology group for racks.