The Canada-UK Deep Submillimeter Survey V: The Submillimeter Properties of Lyman-Break Galaxies

We have used 850$\mu$m maps obtained as part of the Canada-UK Deep Submillimeter Survey (CUDSS) to investigate the sub-mm properties of Lyman-break galaxies (LBGs). We used three samples of Lyman-break galaxies: two from the Canada-France Deep Fields (CFDF) survey covering CUDSS-14 and CUDSS-3, and one from Steidel and collaborators also covering CUDSS-14. We measure a mean flux from both CFDF LBG samples at a level of $\sim2\sigma$ of 0.414 $\pm$ 0.263 mJy for CUDSS-03 and 0.382 $\pm$ 0.206 mJy for CUDSS-14, but the Steidel et al. sample is consistent with zero flux. From this we place upper limits on the Lyman-break contribution to the $850{\mu}m$ background of $\sim$20%. We have also measured the cross-clustering between the LBGs and SCUBA sources. From this measurement we infer a large clustering amplitude of $r_o$ = 11.5 $\pm$ 3.0 $\pm$ 3.0 $h^{-1}$Mpc for the Steidel et al. sample (where the first error is statistical and the second systematic), $r_o$ = 4.5 $\pm$ 7.0 $\pm$ 5.0 $h^{-1}$Mpc for CFDF-14 and $r_o$ = 7.5 $\pm$ 7.0 $\pm$ 5.0 $h^{-1}$Mpc for CFDF-3. The Steidel et al sample, for which we have most only significant detection of clustering is also the largest of the three samples and has spectroscopically confirmed redshifts.Comment: 17 pages, 11 figures, accepted by Ap

Identification of a Structural Determinant Necessary for the Localization and Function of Estrogen Receptor α at the Plasma Membrane

Estrogen receptors (ER) have been localized to the cell plasma membrane (PM), where signal transduction mediates some estradiol (E2) actions. However, the precise structural features of ER that result in membrane localization have not been determined. We obtained a partial tryptic peptide/mass spectrometry analysis of membrane mouse ERα protein. Based on this, we substituted alanine for the determined serine at amino acid 522 within the E domain of wild-type (wt) ERα. Upon transfection in CHO cells, the S522A mutant ERα resulted in a 62% decrease in membrane receptor number and reduced colocalization with caveolin 1 relative to those with expression of wt ERα. E2 was significantly less effective in stimulating multiple rapid signals from the membranes of CHO cells expressing ERα S522A than from those of CHO cells expressing wt ERα. In contrast, nuclear receptor expression and transcriptional function were very similar. The S522A mutant was also 60% less effective than wt ERα in binding caveolin 1, which facilitates ER transport to the PM. All functions of ERα mutants with other S-to-A substitutions were comparable to those of wt ER, and deletion of the A/B or C domain had little consequence for membrane localization or function. Transfection of ERα S522A into breast cancer cells that express native ER downregulated E2 binding at the membrane, signaling to ERK, and G(1)/S cell cycle events and progression. However, there was no effect on the E2 transactivation of an ERE-luciferase reporter. In summary, serine 522 is necessary for the efficient translocation and function of ERα at the PM. The S522A mutant also serves as a dominant-negative construct, identifying important functions of E2 that originate from activating PM ER

Rethinking US Policy Towards North Korea

Created as part of the the 2011 Jackson School for International Studies SIS 495: Task force. Clark W. Sorensen, Task Force Advisor; Ambassador Thomas Hubbard, Evaluator; Marianne Fisher and Marcus Foster, Coordinators.Negotiations between the United States and the Democratic People’s Republic of Korea have failed. The United States has engaged the DPRK through a multitude of approaches with some success, though they have all ultimately deteriorated due to policy inconsistency and inability to predict and accommodate the DPRK’s erratic behavior. In the last decade,particularly with the DPRK’s successful development of nuclear weapon capabilities, relations with North Korea have collapsed due to various factors. Many failures can be attributed to US policy inconsistency towards the DPRK, especially during periods of administration change in the United States; these failures, consequently, have been perpetuated by the DPRK’s unpredictable reactions. Returning to negotiations through engaging the DPRK regime directly is increasingly important to national and global security as North Korea continues to proliferate

The JCMT Nearby Galaxies Legacy Survey - VIII : CO data and the L -L correlation in the SINGS sample

The James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey (NGLS) comprises an Hi-selected sample of 155 galaxies spanning all morphological types with distances less than 25Mpc. We describe the scientific goals of the survey, the sample selection and the observing strategy. We also present an atlas and analysis of the CO J=3 - 2 maps for the 47 galaxies in the NGLS which are also part of the Spitzer Infrared Nearby Galaxies Survey. We find a wide range of molecular gas mass fractions in the galaxies in this sample and explore the correlation of the far-infrared luminosity, which traces star formation, with the CO luminosity, which traces the molecular gas mass. By comparing the NGLS data with merging galaxies at low and high redshift, which have also been observed in the CO J=3 - 2 line, we show that the correlation of far-infrared and CO luminosity shows a significant trend with luminosity. This trend is consistent with a molecular gas depletion time which is more than an order of magnitude faster in the merger galaxies than in nearby normal galaxies. We also find a strong correlation of the L /L ratio with the atomic-to-molecular gas mass ratio. This correlation suggests that some of the far-infrared emission originates from dust associated with atomic gas and that its contribution is particularly important in galaxies where most of the gas is in the atomic phase.Peer reviewe