Line strength variations in beta Cephei

The line strength variations of the resonance line of C IV (1550A, 2s 2S - 2P) observed by OAO-2 were confirmed by IUE observations. In addition, the NV resonance line (1204A, 2s 2S - 2P), the Si III line (1206A, 3p 1P-1D, multiplet 11) and the Si IV resonance line (1395A, 3s 2S - 2P) all vary in line strength essentially in phase with the C IV variation. The (preliminary) period of the variation is 6.02/12.04 days

Cepheid Modeling

Mathematical techniques are used to model the instability behavior of Cepheid variables

Current problems in Stellar Pulsation Instabilities

Instabilities of pulsating variable stars, such as Cepheid variables, Cepheid masses, early-type variable stars, White Dwarfs, and Mira variables, are discussed

Partition functions and equations of state in plasmas

Partition functions and equations of state of He, H, N, O, Ne, Ar, and solar plasmas - table

Wind Circulation in Selected Rotating Magnetic Early-B Stars

The rotating magnetic B stars have oblique dipolar magnetic fields and often anomalous helium and metallic compositions. These stars develop co-rotating torus-shaped clouds by channelling winds from their magnetic poles to an anchored planar disk over the magnetic equator. The line absorptions from the cloud can be studied as the complex rotates and periodically occults the star. We describe an analysis of the clouds of four stars (HD184927, beta Cep, sigma Ori E, and HR6684). From line synthesis models, we find that the metallic compositions are spatially uniform over the stars' surfaces. Next, using the Hubeny CIRCUS code, we demonstate that periodic UV continuum fluxes can be explained by the absorption of low-excitation lines. The analysis also quantifies the cloud temperatures, densities, and turbulences, which appear to increase inward toward the stars. The temperatures range from about 12,000K for the weak Fe lines up to temperatures of 33,000K for N V absorptions, which is in excess of temperatures expected from radiative equilibrium. The spectroscopic hallmark of this stellar class is the presence of strong C IV and N V resonance line absorptions at occultation phases and of redshifted emissions at magnetic pole-on phases. The emissions have characteristics which seem most compatible with the generation of high-energy shocks at the wind-cloud interface, as predicted by Babel.Comment: 19 pages, Latex plus 6 figures A&A single-spaced, accepted by Astronomy & Astrophysics. Files available by ftp at nobel.stsci.edu/pub/aapaper

Public Benefits of Undeveloped Lands on Urban Outskirts: Non-Market Valuation Studies and their Role in Land Use Plans

Over the past three decades, the economics profession has developed methods for estimating the public benefits of green spaces, providing an opportunity to incorporate such information into land-use planning. While federal regulations routinely require such estimates for major regulations, the extent to which they are used in local land use plans is not clear. This paper reviews the literature on public values for lands on urban outskirts, not just to survey their methods or empirical findings, but to evaluate the role they have played--or have the potential to play-- in actual land use plans. Based on interviews with authors and representatives of funding agencies and local land trusts, it appears that academic work has had a mixed reception in the policy world. Reasons for this include a lack of interest in making academic work accessible to policy makers, emphasizing revealed preference methods which are inconsistent with policy priorities related to nonuse values, and emphasis on benefit-cost analyses. Nevertheless, there are examples of success stories that illustrate how such information can play a vital role in the design of conservation policies. Working Paper 07-2

Diblock copolymers at a homopolymer-homopolymer-interface: a Monte Carlo simulation

The properties of diluted symmetric A-B diblock copolymers at the interface between A and B homopolymer phases are studied by means of Monte Carlo (MC) simulations of the bond fluctuation model. We calculate segment density profiles as well as orientational properties of segments, of A and B blocks, and of the whole chain. Our data support the picture of oriented ``dumbbells'', which consist of mildly perturbed A and B Gaussian coils. The results are compared to a self consistent field theory (SCFT) for single copolymer chains at a homopolymer interface. We also discuss the number of interaction contacts between monomers, which provide a measure for the ``active surface'' of copolymers or homopolymers close to the interface