7,288 research outputs found
A new effective exchange rate index for the dollar and its implications for U.S. merchandise trade
An introduction to a new exchange-rate index to measure the foreign-exchange value of the dollar. The authors develop a model of U.S. merchandise trade, featuring the new index.Foreign exchange rates ; Dollar, American
Superfluid transitions in bosonic atom-molecule mixtures near Feshbach resonance
We study bosonic atoms near a Feshbach resonance, and predict that in
addition to a standard normal and atomic superfluid phases, this system
generically exhibits a distinct phase of matter: a molecular superfluid, where
molecules are superfluid while atoms are not. We explore zero- and
finite-temperature properties of the molecular superfluid (a bosonic,
strong-coupling analog of a BCS superconductor), and study quantum and
classical phase transitions between the normal, molecular superfluid and atomic
superfluid states.Comment: 4 revtex pages, 3 eps figures; submitted to PR
Particle tunneling through a polarizable insulator
The tunneling probability between two leads connected by a molecule, a chain,
a film, or a bulk polarizable insulator is investigated within a model of an
electron tunneling from lead A to a state higher in energy, describing the
barrier, and from there to lead B. To describe the possibility of energy
exchange with excitations of the molecule or the insulator we couple the
intermediate state to a single oscillator or to a spectrum of these,
respectively. In the single-oscillator case we find for weak coupling that the
tunneling is weakly suppressed by a Debye-Waller-type factor. For stronger
coupling the oscillator gets 'stiff' and we observe a suppression of tunneling
since the effective barrier is increased. The probability for the electron to
excite the oscillator increases with the coupling. In the case of a film, or a
bulk barrier the behavior is qualitatively the same as in the single oscillator
case. An insulating chain, as opposed to a film or a bulk connecting the two
leads,shows an 'orthogonality catastrophe' similar to that of an electronic
transition in a Fermi gas.Comment: 4 pages, 1 figur
Carbon dioxide kinetics and capnography during critical care
Greater understanding of the pathophysiology of carbon dioxide kinetics during steady and nonsteady state should improve, we believe, clinical care during intensive care treatment. Capnography and the measurement of end-tidal partial pressure of carbon dioxide (PETCO(2)) will gradually be augmented by relatively new measurement methodology, including the volume of carbon dioxide exhaled per breath (VCO(2,br)) and average alveolar expired PCO(2) (PAÌ…EÌ…CO(2)). Future directions include the study of oxygen kinetics
Report from space plasma science
Space plasma science, especially plasma experiments in space, is discussed. Computational simulations, wave generation and propagation, wave-particle interactions, charged particle acceleration, particle-particle interactions, radiation transport in dense plasmas, macroscopic plasma flow, plasma-magnetic field interactions, plasma-surface interactions, prospects for near-term plasma science experiments in space and three-dimensional plasma experiments are among the topics discussed
Ground failure along the New River caused by the October 1979 Imperial Valley earthquake sequence
We recognized a number of ground failures along the south bank of the New River north of Brawley, California, following the 15 October 1979 Imperial Valley, California, earthquake sequence. The zone includes a large pond and numerous sand boils, apparently caused by liquefaction, near the Del Rio Country Club. These ground failures, together with failures at the New River bridge west of Brawley and at Wiest Lake, form a discontinuous zone 10 km long. While this zone appears to coincide with the aftershocks following the 16 October 1979, M_L 5.8, Brawley earthquake (the largest aftershock of the Imperial Valley earthquake), a cause and effect relationship cannot be demonstrated. No evidence of tectonic surface faulting could be found
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