Nuclear structure and double beta decay: Two neutrino mode

The decay rate of the 2ν double beta decay is calculated. The effects of pairing, static quadrupole deformation, spin-isospin polarization, and the Δ_(33) isobar admixtures on the nuclear matrix elements are studied and the relation of the 2ν ββ rate and the β^- and β^+ strength is stressed. In agreement with other calculations, we predict a faster decay rate than has been observed experimentally in ^(82)Se, ^(130)Te, and ^(150)Nd

Calculations for mosaics with plane and curved grating elements quarterly progress report no. 4

Review of calculations of plane grating mosaic for photon energ

What happened to risk dispersion?

The turbulence in credit and funding markets in the second half of 2007 is disturbing evidence that risk dispersion in financial markets has been less effective than expected. Investors appear to have acquired risks that they did not understand. Much more worrisome, however, is the evidence that major financial firms did not succeed in shedding risks so much as in transferring them among their own business lines, resulting in an unintended concentration of risks on their own balance sheets. In order to restore confidence in the near term, and to put credit creation on a more sustainable path in the future, supervisory authorities, central banks and governments will first need to understand why the much-vaunted dispersion of risk fell so far short of expectations. The “reluctance to lend” which underlies these strains in money markets was widely attributed to concerns about the financial condition of borrowers, as a consequence of uncertainty about the value of assets on the borrowers’ balance sheets, and also to insuffi cient attention to liquidity management by financial firms. But the focus on uncertainty about borrowers ignores the awkward fact that the major financial intermediaries are both lenders and borrowers themselves and their reluctance to lend significantly reflects a defensive reaction to their own uncertainties about their own balance sheets. Better stress testing for liquidity as well as solvency would certainly be beneficial. Yet a major cause of the strains in credit and funding markets has been the apparent inability of many firms to anticipate the interaction of their various on- and off-balance sheet exposures and, particularly, to understand the velocity of their off-balance sheet activities and how these affected their overall exposures. In considering potential remedies to the credit market’s turbulence and to the apparent failure of risk dispersion, the authorities should first reflect on their own role in the trend of pushing risks off of bank balance sheets.

Seasonal changes in growth of coho salmon (Oncorhynchus kisutch) off Oregon and Washington and concurrent changes in the spacing of scale circuli

In this study we present new information on seasonal variation in absolute growth rate in length of coho salmon (Oncorhynchus kisutch) in the ocean off Oregon and Washington, and relate these changes in growth rate to concurrent changes in the spacing of scale circuli. Average spacing of scale circuli and average rate of circulus formation were significantly and positively correlated with average growth rate among groups of juvenile and maturing coho salmon and thus could provide estimates of growth between age groups and seasons. Regression analyses indicated that the spacing of circuli was proportional to the scale growth rate raised to the 0.4−0.6 power. Seasonal changes in the spacing of scale circuli reflected seasonal changes in apparent growth rates of fish. Spacing of circuli at the scale margin was greatest during the spring and early summer, decreased during the summer, and was lowest in winter or early spring. Changes over time in length of fish caught during research cruises indicated that the average growth rate of juvenile coho salmon between June and September was about 1.3 mm/d and then decreased during the fall and winter to about 0.6 mm/d. Average growth rate of maturing fish was about 2 mm/d between May and June, then decreased to about 1 mm/d between June and September. Average apparent growth rates of groups of maturing coded-wire−tagged coho salmon caught in the ocean hook-and-line fisheries also decreased between June and September. Our results indicate that seasonal change in the spacing of scale circuli is a useful indicator of seasonal change in growth rate of coho salmon in the ocean

The Partially-Split Hall Bar: Tunneling in the Bosonic Integer Quantum Hall Effect

We study point-contact tunneling in the integer quantum Hall state of bosons. This symmetry-protected topological state has electrical Hall conductivity equal to $2 e^2/h$ and vanishing thermal Hall conductivity. In contrast to the integer quantum Hall state of fermions, a point contact can have a dramatic effect on the low energy physics. In the absence of disorder, a point contact generically leads to a partially-split Hall bar geometry. We describe the resulting intermediate fixed point via the two-terminal electrical (Hall) conductance of the edge modes. Disorder along the edge, however, both restores the universality of the two-terminal conductance and helps preserve the integrity of the Hall bar within the relevant parameter regime.Comment: 12 pages, 5 figures; v.2: typos fixed and clarified some argument

Fatalism and Future Contingents

In this paper I address issues related to the problem of future contingents and the metaphysical doctrine of fatalism. Two classical responses to the problem of future contingents are the third truth value view and the all-false view. According to the former, future contingents take a third truth value which goes beyond truth and falsity. According to the latter, they are all false. I here illustrate and discuss two ways to respectively argue for those two views. Both ways are similar in spirit and intimately connected with fatalism, in the sense that they engage with the doctrine of fatalism and accept a large part of a standard fatalistic machinery