CP violation and rare Bs decays at the Tevatron

This note gives updates on three results from the Fermilab Tevatron p¯p collider operating at √s = 1.96TeV. The results presented include: the D0 dimuon charge asymmetry; the measurement of the CP-violating phase φs in the decay Bs → J/ψφ from both CDF and D0; and the most recent results from both CDF and D0 on the search for the ultra-rare decay Bs → μ+μ−

Laser Guide Star Adaptive Optics Integral Field Spectroscopy of a Tightly Collimated Bipolar Jet from the Herbig Ae star LkHa 233

We have used the integral field spectrograph OSIRIS and laser guide star adaptive optics at Keck Observatory to obtain high angular resolution (0.06"), moderate spectral resolution (R ~ 3800) images of the bipolar jet from the Herbig Ae star LkHa 233, seen in near-IR [Fe II] emission at 1.600 & 1.644 microns. This jet is narrow and tightly collimated, with an opening angle of only 9 degrees, and has an average radial velocity of ~ 100 km/s. The jet and counterjet are asymmetric, with the red-shifted jet much clumpier than its counterpart at the angular resolution of our observations. The observed properties are in general similar to jets seen around T Tauri stars, though it has a relatively large mass flux of (1.2e-7 +- 0.3e-7) M_sun/year, near the high end of the observed mass flux range around T Tauri stars. We also spatially resolve an inclined circumstellar disk around LkHa 233, which obscures the star from direct view. By comparison with numerical radiative transfer disk models, we estimate the disk midplane to be inclined i = 65 +- 5 degrees relative to the plane of the sky. Since the star is seen only in scattered light at near-infrared wavelengths, we detect only a small fraction of its intrinsic flux. Because previous estimates of its stellar properties did not account for this, either LkHa 233 must be located closer than the previously believed, or its true luminosity must be greater than previously supposed, consistent with its being a ~4 M_sun star near the stellar birthline.Comment: Accepted for publication in the Ap

Motor-starting characteristics of two inductor alternators

Motor starting characteristics of two inductor alternator

On the changes in the physical properties of the ionized region around the Weigelt structures in Eta Carinae over the 5.54-yr spectroscopic cycle

We present HST/STIS observations and analysis of two prominent nebular structures around the central source of Eta Carinae, the knots C and D. The former is brighter than the latter for emission lines from intermediate or high ionization potential ions. The brightness of lines from intermediate and high ionization potential ions significantly decreases at phases around periastron. We do not see conspicuous changes in the brightness of lines from low ionization potential (<13.6 eV) that the total extinction towards the Weigelt structures is that the total extinction towards the Weigelt structures is AsubV =2/0. that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of that the total extinction towards the Weigelt structures is AV = 2.0. Weigelt C and D are characterized by an electron density of 10exp6.9 cm-3 that does not significantly change throughout the orbital cycle. The electron temperature varies from 5500 K (around periastron) to 7200 K (around apastron). The relative changes in the brightness of He I lines are well reproduced by the variations in the electron temperature alone. We found that, at phases around periastron, the electron temperature seems to be higher for Weigelt C than that of D. The Weigelt structures are located close to the Homunculus equatorial plane, at a distance of about 1240 AU from the central source. From the analysis of proper motion and age, the Weigelt complex can be associated with the equatorial structure called the Butterfly Nebula surrounding the central binary system.Comment: 19 pages, 18 figure

The Molecular Gas Environment around Two Herbig Ae/Be Stars: Resolving the Outflows of LkHa 198 and LkHa 225S

Observations of outflows associated with pre-main-sequence stars reveal details about morphology, binarity and evolutionary states of young stellar objects. We present molecular line data from the Berkeley-Illinois-Maryland Association array and Five Colleges Radio Astronomical Observatory toward the regions containing the Herbig Ae/Be stars LkHa 198 and LkHa 225S. Single dish observations of 12CO 1-0, 13CO 1-0, N2H+ 1-0 and CS 2-1 were made over a field of 4.3' x 4.3' for each species. 12CO data from FCRAO were combined with high resolution BIMA array data to achieve a naturally-weighted synthesized beam of 6.75'' x 5.5'' toward LkHa 198 and 5.7'' x 3.95'' toward LkHa 225S, representing resolution improvements of factors of approximately 10 and 5 over existing data. By using uniform weighting, we achieved another factor of two improvement. The outflow around LkHa 198 resolves into at least four outflows, none of which are centered on LkHa 198-IR, but even at our resolution, we cannot exclude the possibility of an outflow associated with this source. In the LkHa 225S region, we find evidence for two outflows associated with LkHa 225S itself and a third outflow is likely driven by this source. Identification of the driving sources is still resolution-limited and is also complicated by the presence of three clouds along the line of sight toward the Cygnus molecular cloud. 13CO is present in the environments of both stars along with cold, dense gas as traced by CS and (in LkHa 225S) N2H+. No 2.6 mm continuum is detected in either region in relatively shallow maps compared to existing continuum observations.Comment: 14 pages, 10 figures (5 color), accepted for publication in Ap

Waiting in the Wings: Reflected X-ray Emission from the Homunculus Nebula

We report the first detection of X-ray emission associated with the Homunculus Nebula which surrounds the supermassive star Eta Carinae. The emission is characterized by a temperature in excess of 100 MK, and is consistent with scattering of the time-delayed X-ray flux associated with the star. The nebular emission is bright in the northwestern lobe and near the central regions of the Homunculus, and fainter in the southeastern lobe. We also report the detection of an unusually broad Fe K fluorescent line, which may indicate fluorescent scattering off the wind of a companion star or some other high velocity outflow. The X-ray Homunculus is the nearest member of the small class of Galactic X-ray reflection nebulae, and the only one in which both the emitting and reflecting sources are distinguishable.Comment: 17 pages, 5 figures, accepted by Ap

Getting Jobs, Keeping Jobs, and Earning a Living Wage: Can Welfare Reform Work?

Most discussions of welfare and work have focused on how demographic characteristics, schooling, training, and work experience limit welfare mothers’ employment and wages, but they have largely ignored factors such as inappropriate workplace behaviors, expectations of discrimination and harassment, depression, alcoholism, and domestic violence, all of which may affect welfare mothers and make employment difficult. In this paper we review the prevalence of these individual-level barriers and argue that they, in combination with an economy which does not pay low-skill workers well, are likely to impede employment and self-sufficiency for a large proportion of welfare mothers. At the end of the review, we summarize the current state of knowledge about barriers to the employment of welfare recipients and suggest several ways in which welfare-to-work programs might address these barriers.

Recent Decisions

Comments on recent decisions by James M. Corcoran, Manuel A. Sequeira, D. D. Robertson, Joseph B. Joyce, A. J. Deutsch, Lawrence J. Dolan, Otto K. Hilbert, and J. Robert Geiman