947 research outputs found
Averaging along degenerate flows on the annulus
Periodic flows on the annulus are considered. For flows that degenerate (i.e.
the flow becomes arbitrarily slow along some flow lines) a convergence rate for
the averaging of functions along the flow is obtained. This rate -- which is
slower than the rate obtained for flows that do not degenerate (i.e. when there
is a spectral gap) -- holds on an appropriate functional subspace. The main
ingredient is an estimate of the density of the spectrum of the generator near
zero.Comment: 15 pages. All comments are welcom
Moduli Decays and Gravitinos
One proposed solution of the moduli problem of string cosmology requires that
the moduli are quite heavy, their decays reheating the universe to temperatures
above the scale of nucleosynthesis. In many of these scenarios, the moduli are
approximately supersymmetric; it is then crucial that the decays to gravitinos
are helicity suppressed. In this paper, we discuss situations where these
decays are, and are not, suppressed. We also comment on a possible gravitino
problem from inflaton decay.Comment: 16 pages, version to appear in Physical Review
U.S. international transactions in 1998
U.S. external deficits widened substantially in 1998 because of the disparity between the rapid pace of U.S. economic growth and sluggish growth abroad and also because of the decline in the price competitiveness of U.S. goods associated with the appreciation of the dollar. The nominal current account deficit reached 155 billion in 1997; the 1998 deficit was 2.7 percent of U.S. gross domestic product, the largest share since 1987. Most of the widening in the deficit was in trade in goods and services. The financial crises in Asia that emerged in the second half of 1997 caused U.S. exports to drop sharply in the first half of 1998. Robust U.S. domestic demand was largely responsible for the brisk rise in imports during the year. Net investment income was negative in 1998 for the second consecutive year. Cumulative deficits in the current account, and the associated capital inflows that have persisted since 1982, have resulted in payments of income on foreign investment in the United States growing more rapidly than receipts of income on U.S. investments abroad. The fallout from the financial crises in emerging markets is likely to have further negative consequences for U.S. external balances in 1999.International trade ; Exports ; Imports
Relaciones etiológicas entre el síndrome de la liebre marrón europea -SLME- y la enfermedad vírica hemorrágica del conejo -EVH-
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