16,731 research outputs found
Nonlinear I-V Characteristics of a Mesoscopic Conductor
We present a general theoretical formulation, based on nonequilibrium Green's
functions, for nonlinear DC transport in multi-probe mesoscopic conductors. The
theory is gauge invariant and is useful for the predictions of current-voltage
characteristics and the nonequilibrium charge pile-ups inside the conductor. We
have provided a detailed comparison between the gauge invariant scattering
matrix theory and our theory. We have also given several examples where the I-V
curve can be obtained analytically. The effects of exchange and correlation
have been considered explicitly
Dust in the Local Group
How dust absorbs and scatters starlight as a function of wavelength (known as
the interstellar extinction curve) is crucial for correcting for the effects of
dust extinction in inferring the true luminosity and colors of reddened
astrophysical objects. Together with the extinction spectral features, the
extinction curve contains important information about the dust size
distribution and composition. This review summarizes our current knowledge of
the dust extinction of the Milky Way, three Local Group galaxies (i.e., the
Small and Large Magellanic Clouds, and M31), and galaxies beyond the Local
Group.Comment: 21 pages, 11 figures; invited review article published in "LESSONS
FROM THE LOCAL GROUP -- A Conference in Honour of David Block and Bruce
Elmegreen" eds. Freeman, K.C., Elmegreen, B.G., Block, D.L. & Woolway, M.
(SPRINGER: NEW YORK), pp. 85-10
Is Drug Coverage a Free Lunch? Cross-Price Elasticities and the Design of Prescription Drug Benefits
Recently, many U.S. employers have adopted less generous prescription drug benefits. In addition, the U.S. began to offer prescription drug insurance to approximately 42 million Medicare beneficiaries in 2006. We use data on individual health insurance claims and benefit data from 1997-2003 to study the effects of changing consumers' co-payments for prescription drugs on the quantity demanded and expenditure on prescription drugs, inpatient care and outpatient care. We allow for effects both in the year of the co-payment change and in the year following the change. Our results show that increases in prescription drug prices reduce both the use of and spending on prescription drugs. However, consumers substitute the use of outpatient care and inpatient care for prescription drug use, and about 35% of the expenditure reductions on prescription drugs are offset by the increases in other spending.
- …