Universality of Decay out of Superdeformed Bands in the 190 Mass Region

Superdeformed nuclei in the 190 mass region exhibit a striking universality in their decay-out profiles. We show that this universality can be explained in the two-level model of superdeformed decay as related to a strong separation of energy scales: a higher scale related to the nuclear interactions, and a lower scale caused by electromagnetic decay. Furthermore, we present the results of the two-level model for all decays for which sufficient data are known, including statistical extraction of the matrix element for tunneling through the potential barrier.Comment: 7 pages, 3 figures. v2: some minor clarifications, minor correction to Fig.

How to measure the spreading width for decay of superdeformed nuclei

A new expression for the branching ratio for the decay via the E1 process in the normal-deformed band of superdeformed nuclei is given within a simple two-level model. Using this expression, the spreading or tunneling width Gamma^downarrow for superdeformed decay can be expressed entirely in terms of experimentally known quantities. We show how to determine the tunneling matrix element V from the measured value of Gamma^downarrow and a statistical model of the energy levels. The accuracy of the two-level approximation is verified by considering the effects of the other normal-deformed states.Comment: 4 pages, 4 figure

Fit for work? Health, employability and challenges for the UK welfare reform agenda

This article introduces a special issue of Policy Studies entitled “Fit for work? Health, employability and challenges for the UK welfare reform agenda”. Growing from a shared concern over the need to expand the evidence base around the processes that led to large numbers of people claiming disability benefits in the UK, it brings together contributions from leading labour market and social policy researchers providing evidence and commentary on major reforms to Incapacity Benefit (IB) in the UK. This special issue address three key questions: what are the main causes of the long-term rise in the number of people claiming IBs; what will reduce the number of claimants; and what is likely to deliver policy effectively and efficiently? This introduction first explains and examines the challenges to reforms to IB in the UK, and then, in conclusion, highlights the answers to the previous three questions – first, labour market restructuring and marginalisation have driven the rise in numbers claiming IBs. Second, economic regeneration in the Britain’s less prosperous areas coupled with intensive and sustained supply-side support measures will bring numbers down. Third, delivery need to be flexible and tailored to individual needs and needs to be able to access local and expert knowledge in a range of organisations, including Job Centre Plus, the NHS as well as the private and voluntary sectors

Quantum Necking in Stressed Metallic Nanowires

When a macroscopic metallic wire is subject to tensile stress, it necks down smoothly as it elongates. We show that nanowires with radii comparable to the Fermi wavelength display remarkably different behavior. Using concepts from fluid dynamics, a PDE for nanowire shape evolution is derived from a semiclassical energy functional that includes electron-shell effects. A rich dynamics involving movement and interaction of kinks connecting locally stable radii is found, and a new class of universal equilibrium shapes is predicted.Comment: 4 pages, 3 postscript figures. New result on universal equilibrium shape

Power Doppler sonography in tenosynovitis: significance of the peritendinous hypoechoic rim.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135464/1/jum1998172103.pd

Characterization of the purified vitamin K-dependent gamma-glutamyl carboxylase.

Vitamin K-dependent carboxylase, purified from bovine liver, has properties similar to those reported for the carboxylase activity present in crude, solubilized microsomes. The purified carboxylase was found to possess the vitamin K epoxidase activity, believed to be essential for vitamin K-dependent carboxylation, but did not contain vitamin K epoxide reductase activity. Kinetic studies of the carboxylase done under defined conditions were complicated by the non-Michaelis-Menten kinetic behavior observed for reactions with two of the enzymes substrates, FLEEL and vitamin K1 hydroquinone. Initial rate experiments with the substrate FLEEL demonstrated behavior consistent with substrate inhibition and gave half-maximal activity at 1 mM FLEEL. Experiments with the substrate vitamin K1 hydroquinone also displayed non-Michaelis-Menten kinetics, as maximal activity was reached prematurely in relation to behavior at lower concentrations. Half-maximal activity was observed at 35 microM vitamin K1 hydroquinone. Initial rate experiments with varying NaH14CO3 concentration displayed Michaelis-Menten kinetics and gave a Km(app) of 0.29 mM. At cosubstrate concentrations chosen to obtain near-maximal activity, initial rate studies with varying NaH14CO3 concentration indicated a kcat near 1.0 s-1. Removal of the fourth substrate, oxygen, resulted in the loss of more than 99% of carboxylase activity. The sulfhydryl reagent N-ethylmaleimide inhibited carboxylase irreversibly, as did the anticoagulant warfarin

The number of transmission channels through a single-molecule junction

We calculate transmission eigenvalue distributions for Pt-benzene-Pt and Pt-butadiene-Pt junctions using realistic state-of-the-art many-body techniques. An effective field theory of interacting $\pi$-electrons is used to include screening and van der Waals interactions with the metal electrodes. We find that the number of dominant transmission channels in a molecular junction is equal to the degeneracy of the molecular orbital closest to the metal Fermi level.Comment: 9 pages, 8 figure

Kondo Resonance in a Mesoscopic Ring Coupled to a Quantum Dot: Exact Results for the Aharonov-Bohm/Casher Effects

We study the persistent currents induced by both the Aharonov-Bohm and Aharonov-Casher effects in a one-dimensional mesoscopic ring coupled to a side-branch quantum dot at Kondo resonance. For privileged values of the Aharonov-Bohm-Casher fluxes, the problem can be mapped onto an integrable model, exactly solvable by a Bethe ansatz. In the case of a pure magnetic Aharonov-Bohm flux, we find that the presence of the quantum dot has no effect on the persistent current. In contrast, the Kondo resonance interferes with the spin-dependent Aharonov-Casher effect to induce a current which, in the strong-coupling limit, is independent of the number of electrons in the ring.Comment: Replaced with published version; 5 page