Introduction to Library Trends 56 (1) Summer 2007: Preserving Cultural Heritage

published or submitted for publicatio

Preliminary results on two-dimensional interferometry of HL Tau

Preliminary two-dimensional speckle interferometry results of HL Tau were found to be qualitatively similar to those found with one-dimensional slit scanning techniques; results consist of a resolved component (approximately 0.7 arcsec in size) and an unresolved component. Researchers are currently reducing the rest of the data (taken on three different telescopes and at three different wavelengths) and are also exploring other high resolution methods like the shift and add technique and selecting only the very best images for processing. The availability of even better two-dimensional arrays within the next couple of years promises to make speckle interferometry and other high resolution techniques very powerful and exiting tools for probing a variety of objects in the subarcsec regime

Lattice Gauge Theory Sum Rule for the Shear Channel

An exact expression is derived for the $(\omega,p)=0$ thermal correlator of shear stress in SU($N_c$) lattice gauge theory. I remove a logarithmic divergence by taking a suitable linear combination of the shear correlator and the correlator of the energy density. The operator product expansion shows that the same linear combination has a finite limit when $\omega\to\infty$. It follows that the vacuum-subtracted shear spectral function vanishes at large frequencies at least as fast as $\alpha_s^2(\omega)$ and obeys a sum rule. The trace anomaly makes a potential contribution to the spectral sum rule which remains to be fully calculated, but which I estimate to be numerically small for $T\gtrsim 3T_c$. By contrast with the bulk channel, the shear channel spectral density is then overall enhanced as compared to the spectral density in vacuo.Comment: 11 pages, no figure

From complacency to crisis: financial risk taking in the early 21st century

During the first half of this decade, the belief that new financial products would adequately shield investors from risk encouraged financial flows to less creditworthy households and businesses. By late 2006, U.S. financial markets were flashing warning signals of a potential financial crisis. ; In a sign that investors had become too complacent, risk premiums had all but vanished in junk bond and emerging-market interest rate spreads. Then, conditions changed abruptly. In the important and usually stable market for asset-backed commercial paper, premiums on three-month paper over Treasury bills jumped from 0.17 percentage point in February 2007 to 2.15 points in August. Meanwhile, rising subprime mortgage defaults led investors to abandon their sanguine beliefs about the risk of many mortgage and nonmortgage products. ; The backdrop for these events was a period of macroeconomic stability that fed complacency about risk. This relatively benign economic environment, when combined with the new, structured financial products, increased financial flows to nonprime mortgage and business borrowers. The result was an overeager acceptance of risk taking that began correcting itself only after mounting subprime mortgage defaults reverberated through the broader financial markets.Risk ; Financial markets

Comparison of seismic signatures of flares obtained by SOHO/MDI and GONG instruments

The first observations of seismic responses to solar flares were carried out using time-distance (TD) and holography techniques applied to SOHO/MDI Dopplergrams obtained from space and un-affected by terrestrial atmospheric disturbances. However, the ground-based network GONG is potentially a very valuable source of sunquake observations, especially in cases where space observations are unavailable. In this paper we present updated technique for pre-processing of GONG observations for application of subjacent vantage holography. Using this method and TD diagrams we investigate several sunquakes observed in association with M and X-class solar flares and compare the outcomes with those reported earlier using MDI data. In both GONG and MDI datasets, for the first time, we also detect the TD ridge associated with the September 9, 2001 flare. Our results show reassuringly positive identification of sunquakes from GONG data that can provide further information about the physics of seismic processes associated with solar flares.Comment: 19 pages, 6 figures, accepted to Astrophysical Journa

Keeneland Conference Plenary Sessions: Harvey V. Fineberg

Healthy communities are essential for healthy individuals. Healthy communities can only exist when preventive measures are taken. When prevention programs are implemented, negative health outcomes can be avoided before they even start. A necessary part of these successful prevention methods requires great research and evidence based practice. Dr. Harvey Fineberg, president of the Institute of Medicine and keynote speaker at the Keeneland Conference, addressed the audience on why good science is imperative to the public health community. It cannot just left up to chance on whether an intervention will work or not; rather it needs to be thoroughly reasoned, grounded in evidence, and be assured to have positive outcomes. Fineberg tells us not to be afraid of using good science and packaging it in a way that will make sense to both policy makers and the general public alike