A search for correlations between gamma-ray burst variability and afterglow onset

We compared the time (or time limit) of onset for optical afterglow emission to the γ-ray variability V in 76 gamma-ray bursts with redshifts. In the subset (25 cases) with the rise evident in the data, we fit the shape of the onset peak as well and compared the rising and decaying indices to V. We did not find any evidence for any patterns between these properties and there is no statistical support for any correlations. This indicates a lack of connection between irregularities of the prompt γ-ray emission and the establishment of the afterglow phase. In the ordinary prompt internal shocks interpretation, this would indicate a lack of relationship between V and the bulk Lorentz factor of the event

A Search for Near-Infrared Emission From the Halo of NGC 5907 at Radii of 10 kpc to 30 kpc

We present a search for near-infrared (3.5-5 micron) emission from baryonic dark matter in the form of low-mass stars and/or brown dwarfs in the halo of the nearby edge-on spiral galaxy NGC 5907. The observations were made using a 256 by 256 InSb array with a pixel scale of 17" at the focus of a liquid-helium-cooled telescope carried above the Earth's atmosphere by a sounding rocket. In contrast to previous experiments which have detected a halo around NGC 5907 in the V, R, I, J and K bands at galactic radii 6kpc < r < 10kpc, our search finds no evidence for emission from a halo at 10kpc < r < 30kpc. Assuming a halo mass density scaling as r^(-2), which is consistent with the flat rotation curves that are observed out to radii of 32kpc, the lower limit of the mass-to-light ratio at 3.5-5 microns for the halo of NGC 5907 is 250 (2 sigma) in solar units. This is comparable to the lower limit we have found previously for NGC 4565 (Uemizu et al. 1998). Based on recent models, our non-detection implies that hydrogen- burning stars contribute < 15% of the mass of the dark halo of NGC 5907. Our results are consistent with the previous detection of extended emission at r < 10kpc if the latter is caused by a stellar population that has been ejected from the disk because of tidal interactions. We conclude that the dark halo of NGC 5907, which is evident from rotation curves that extend far beyond 10kpc, is not comprised of hydrogen burning stars.Comment: 12 pages, LateX, plus 6 ps figures. Accepted by ApJ. minor changes, added references, corrected typo

The Serendipitous Extragalactic X-Ray Source Identification (SEXSI) Program. III. Optical Spectroscopy

We present the catalog of 477 spectra from the Serendipitous Extragalactic X-ray Source Identification (SEXSI) program, a survey designed to probe the dominant contributors to the 2-10 keV cosmic X-ray background. Our survey covers 1 deg^2 of sky to 2-10 keV fluxes of 10^-14 erg cm^-2 s^-1, and 2 deg^2 for fluxes of 3 x 10^-14 erg cm^-2 s^-1. Our spectra reach to R <24 and have produced redshifts for 438 hard X-ray sources. The vast majority of the 2-10 keV-selected sample are AGN with redshifts between 0.1 and 3. We find that few sources at z<1 have high X-ray luminosities, reflecting a dearth of high-mass, high-accretion-rate sources at low redshift, a result consistent with other recent wide-area surveys. Half of our sources show significant obscuration, with N_H>10^22 cm^-2, independent of unobscured luminosity. We classify 168 sources as emission-line galaxies; all are X-ray luminous objects with optical spectra lacking both high-ionization lines and evidence of a non-stellar continuum. The redshift distribution of these emission-line galaxies peaks at a significantly lower redshift than does that of the sources we spectroscopically identify as AGN. We conclude that few of these sources can be powered by starburst activity. Stacking spectra for a subset of these sources, we detect [Ne V] emission, a clear signature of AGN activity, confirming that the majority of these objects are Seyfert 2s in which the high-ionization lines are diluted by stellar emission. We find 33 objects lacking broad lines in their optical spectra which have quasar X-ray luminosities (Lx>10^44 erg s^-1), the largest sample of such objects identified to date. In addition, we explore 17 AGN associated with galaxy clusters and find that the cluster-member AGN sample has a lower fraction of broad-line AGN than does the background sample.Comment: Accepted to ApJ; 57 pages, 25 figures, 5 table

A Galaxy at z = 6.545 and Constraints on the Epoch of Reionization

We report the discovery of a Lyman-alpha-emitting galaxy at redshift z=6.545 serendipitously identified in the course of spectroscopic follow-up of hard X-ray sources on behalf of the Serendipitous Extragalactic X-Ray Source Identification (SEXSI) survey. The line flux of the galaxy, 2.1e-17 erg/cm2/s, is similar to line fluxes probed by narrow-band imaging surveys; the 5.2 square-arcminutes surveyed implies a surface density of z~6.5 Lyman-alpha emitters somewhat higher than that inferred from narrow-band surveys. This source marks the sixth Lyman-alpha-emitting galaxy identified at z~6.5, a redshift putatively beyond the epoch of reionization when the damping wings of the neutral hydrogen of the intergalactic medium is capable of severely attenuating Lyman-alpha emission. By comparing the Lyman-alpha emitter luminosity functions at z~5.7 and z~6.5, we infer that the intergalactic medium may remain largely reionized from the local universe out to z~6.5.Comment: 16 pages, 4 figures; submitted to the Astrophysical Journa

Rocketborne instrument to search for infrared emission from baryonic dark matter in galactic halos

We describe the design and performance of the near IR telescope experiment (NITE), a rocket-borne instrument designed to search for IR emission from baryonic dark matter in the halos of nearby edge-on spiral galaxies. A 256 X 256 InSb array at the focus of a 16.5 cm liquid-helium- cooled telescope achieves near-background-limited sensitivity in a 3.5-5.5 micrometers waveband where the local foreground from zodiacal emission is at a minimum. This experiment represents the first scientific application of a low-background IR InSb array, a precursor to the InSb arrays intended for SIRTF, in a space-borne observation. We describe the flight performance of the instrument and preliminary scientific result from an observation of NGC 4565

The Ursinus Weekly, April 23, 1951

Students elect Hartzel, Hall, Ely, Landis: Women\u27s government, YM-YWCA, WAA choose new organization heads • Drs. Armstrong, Mattern, Baker to be speakers • Pa. Dutch film scheduled for benefit show • Nancy Bare and Jackie Keller to share big Arsenic role • Six juniors receive Cub and Key memberships for outstanding work • Lantern deadline set for Friday • Barbara Crawford crowned queen of Junior Prom; 4 attendants named • Editorials: Nominations open; Voting results analyzed • French situation reversed • Truman vs MacArthur • Letters to the editor • Weekly back issues yield untold wealth of pertinent advertisements • Recordak machine aids in library efficiency • Posting of exams recalls looming fate of students • Baseball field dedicated in honor of Dr. John Price • Girls\u27 tennis team downs Swarthmore for second victory • Curtis takes lead in intramural loop • Netmen lose opener to Haverford; Girls triumph over Chestnut Hill, 4-1 • Bears defeat Pharmacy to gain initial triumph, 14-5 • Bears defeat Haverford for second victory, 7-5 • Tennis team wins first court game • Cumpstone breaks own javelin mark as Grizzlies lose • Curtain Club levies charge for using stage materials • Freshmen, Sophs announce picnic at Island Grove • Blood donors must register, get permission if under-age • Dr. Phillips reads unknown Kipling short story to group • Curtain Club to elect • Varsity Club show ready for production Friday night • Red Cross to sponsor water safety instructor\u27s course • Seniors plan picnic • French Club gives recital featuring pianists, vocalists • Newman Club film slated • Nels Fellman elected head of Delta Pi Sigma frathttps://digitalcommons.ursinus.edu/weekly/1566/thumbnail.jp

Rocketborne instrument to search for infrared emission from baryonic dark matter in galactic halos

We describe the design and performance of the near IR telescope experiment (NITE), a rocket-borne instrument designed to search for IR emission from baryonic dark matter in the halos of nearby edge-on spiral galaxies. A 256 X 256 InSb array at the focus of a 16.5 cm liquid-helium- cooled telescope achieves near-background-limited sensitivity in a 3.5-5.5 micrometers waveband where the local foreground from zodiacal emission is at a minimum. This experiment represents the first scientific application of a low-background IR InSb array, a precursor to the InSb arrays intended for SIRTF, in a space-borne observation. We describe the flight performance of the instrument and preliminary scientific result from an observation of NGC 4565

Socioeconomic status and prostate cancer incidence and mortality rates among the diverse population of California

The racial/ethnic disparities in prostate cancer rates are well documented, with the highest incidence and mortality rates observed among African-Americans followed by non-Hispanic Whites, Hispanics, and Asian/Pacific Islanders. Whether socioeconomic status (SES) can account for these differences in risk has been investigated in previous studies, but with conflicting results. Furthermore, previous studies have focused primarily on the differences between African-Americans and non-Hispanic Whites, and little is known for Hispanics and Asian/Pacific Islanders. To further investigate the relationship between SES and prostate cancer among African-Americans, non-Hispanic Whites, Hispanics, and Asian/Pacific Islanders, we conducted a large population-based cross-sectional study of 98,484 incident prostate cancer cases and 8,997 prostate cancer deaths from California. Data were abstracted from the California Cancer Registry, a population-based surveillance, epidemiology, and end results (SEER) registry. Each prostate cancer case and death was assigned a multidimensional neighborhood-SES index using the 2000 US Census data. SES quintile-specific prostate cancer incidence and mortality rates and rate ratios were estimated using SEER*Stat for each race/ethnicity categorized into 10-year age groups. For prostate cancer incidence, we observed higher levels of SES to be significantly associated with increased risk of disease [SES Q1 vs. Q5: relative risk (RR) = 1.28; 95% confidence interval (CI): 1.25–1.30]. Among younger men (45–64 years), African-Americans had the highest incidence rates followed by non-Hispanic Whites, Hispanics, and Asian/Pacific Islanders for all SES levels. Yet, among older men (75–84 years) Hispanics, following African-Americans, displayed the second highest incidence rates of prostate cancer. For prostate cancer deaths, higher levels of SES were associated with lower mortality rates of prostate cancer deaths (SES Q1 vs. Q5: RR = 0.88; 95% CI: 0.92–0.94). African-Americans had a twofold to fivefold increased risk of prostate cancer deaths in comparison to non-Hispanic Whites across all levels of SES. Our findings suggest that SES alone cannot account for the greater burden of prostate cancer among African-American men. In addition, incidence and mortality rates of prostate cancer display different age and racial/ethnic patterns across gradients of SES

Supplementary Data Only: Genomic binding by the Drosophila Myc, Max, Mad/Mnt transcription factor network.

The Myc/Max/Mad transcription factor network is critically involved in cell behavior; however, there is relatively little information on its genomic binding sites. We have employed the DamID method to carry out global genomic mapping of the Drosophila Myc, Max, and Mad/Mnt proteins. Each protein was tethered to Escherichia coli DNA adenine-methyltransferase (Dam) permitting methylation proximal to in vivo binding sites in Kc cells. Microarray analyses of methylated DNA fragments reveals binding to multiple loci on all major Drosophila chromosomes. This approach also reveals dynamic interactions among network members as we find that increased levels of dMax influence the extent of dMyc, but not dMnt, binding. Computer analysis using the REDUCE algorithm demonstrates that binding regions correlate with the presence of E-boxes, CG repeats, and other sequence motifs. The surprisingly large number of directly bound loci ( approximately 15% of coding regions) suggests that the network interacts widely with the genome. Furthermore, we employ microarray expression analysis to demonstrate that hundreds of DamID-binding loci correspond to genes whose expression is directly regulated by dMyc in larvae. These results suggest that a fundamental aspect of Max network function involves widespread binding and regulation of gene expression