Suggested hurricane operational scenario for GOES I-M

Improvements in tropical cyclone forecasts require optimum use of remote sensing capabilities, because conventional data sources cannot provide the necessary spatial and temporal data density over tropical and subtropical oceanic regions. In 1989, the first of a series of geostationary weather satellites, GOES 1-M, will be launched with the capability for simultaneous imaging and sounding. Careful scheduling of the GOES 1-M will enable measurements of both the wind and mass fields over the entire tropical cyclone activity area. The document briefly describes the GOES 1-M imager and sounder, surveys the data needs for hurricane forecasting, discusses how geostationary satellite observations help to meet them, and proposes a GOES 1-M schedule of observations and hurricane relevant derived products

Interaction of H_2 and O_2 on platinum (111)

Abstract Unavailabl

Bargaining in the Shadow of Eminent Domain: Valuing and Apportioning Condemnation Awards Between Landlord and Tenant

Who has a constitutionally protected property interest when the government condemns land subject to a lease? Is it the landlord? The tenant? Or do both parties have property rights that entitle them to compensation? Further, how should the size of the total condemnation award be determined? Should we value the property rights of the landlord and the tenant separately and sum? Or should we value the entire parcel as if it were an undivided fee simple and apportion the award between the landlord and the tenant? If the condemnation award is based on the value of a fee simple and apportioned, who should make this division? Is this an issue of constitutional law as to which the courts have the final say? Or do the principles of constitutional law enunciated by the courts merely provide default rules, i.e., rules that apply only if the parties fail to address the issue of compensation in the lease? In this article, we offer a normative framework for answering these questions. Our approach evolved by working backwards. We started with the question of how to apportion condemnation awards between landlord and tenant. Why, we asked, should courts do the division? Why not let the parties do it themselves? Insofar as commercial leases are concerned, all the prerequisites for efficient bargaining would seem to be present here: a small number of parties (two), an established vehicle for conducting the negotiations (the lease), and both parties typically represented by counsel. Furthermore, provided the issue is addressed in the lease – before condemnation takes place – there should be no problem of ex post strategic behavior

Construction of Parseval wavelets from redundant filter systems

We consider wavelets in L^2(R^d) which have generalized multiresolutions. This means that the initial resolution subspace V_0 in L^2(R^d) is not singly generated. As a result, the representation of the integer lattice Z^d restricted to V_0 has a nontrivial multiplicity function. We show how the corresponding analysis and synthesis for these wavelets can be understood in terms of unitary-matrix-valued functions on a torus acting on a certain vector bundle. Specifically, we show how the wavelet functions on R^d can be constructed directly from the generalized wavelet filters.Comment: 34 pages, AMS-LaTeX ("amsproc" document class) v2 changes minor typos in Sections 1 and 4, v3 adds a number of references on GMRA theory and wavelet multiplicity analysis; v4 adds material on pages 2, 3, 5 and 10, and two more reference

Studying the Pulsation of Mira Variables in the Ultraviolet

We present results from an empirical study of the Mg II h & k emission lines of selected Mira variable stars, using spectra from the International Ultraviolet Explorer (IUE). The stars all exhibit similar Mg II behavior during the course of their pulsation cycles. The Mg II flux always peaks after optical maximum near pulsation phase 0.2-0.5, although the Mg II flux can vary greatly from one cycle to the next. The lines are highly blueshifted, with the magnitude of the blueshift decreasing with phase. The widths of the Mg II lines are also phase-dependent, decreasing from about 70 km/s to 40 km/s between phase 0.2 and 0.6. We also study other UV emission lines apparent in the IUE spectra, most of them Fe II lines. These lines are much narrower and not nearly as blueshifted as the Mg II lines. They exhibit the same phase-dependent flux behavior as Mg II, but they do not show similar velocity or width variations.Comment: 26 pages, 12 figures; AASTEX v5.0 plus EPSF extensions in mkfig.sty; to appear in Ap

Asymmetric polarity reversals, bimodal field distribution, and coherence resonance in a spherically symmetric mean-field dynamo model

Using a mean-field dynamo model with a spherically symmetric helical turbulence parameter alpha which is dynamically quenched and disturbed by additional noise, the basic features of geomagnetic polarity reversals are shown to be generic consequences of the dynamo action in the vicinity of exceptional points of the spectrum. This simple paradigmatic model yields long periods of constant polarity which are interrupted by self-accelerating field decays leading to asymmetric polarity reversals. It shows the recently discovered bimodal field distribution, and it gives a natural explanation of the correlation between polarity persistence time and field strength. In addition, we find typical features of coherence resonance in the dependence of the persistence time on the noise.Comment: 5 pages, 7 figure

Probing the Neutron-Capture Nucleosynthesis History of Galactic Matter

The heavy elements formed by neutron capture processes have an interesting history from which we can extract useful clues to and constraints upon both the characteristics of the processes themselves and the star formation and nucleosynthesis history of Galactic matter. Of particular interest in this regard are the heavy element compositions of extremely metal-deficient stars. At metallicities [Fe/H] <= -2.5, the elements in the mass region past barium (A >= 130-140 have been found (in non carbon-rich stars) to be pure r-process products. The identification of an environment provided by massive stars and associated Type II supernovae as an r-process site seems compelling. Increasing levels of heavy s-process (e.g., barium) enrichment with increasing metallicity, evident in the abundances of more metal-rich halo stars and disk stars, reflect the delayed contributions from the low- and intermediate-mass (M \~ 1-3 Msol) stars that provide the site for the main s-process nucleosynthesis component during the AGB phase of their evolution. New abundance data in the mass region 60 <~ A <~ 130 is providing insight into the identity of possible alternative r-process sites. We review recent observational studies of heavy element abundances both in low metallicity halo stars and in disk stars, discuss the observed trends in light of nucleosynthesis theory, and explore some implications of these results for Galactic chemical evolution, nucleosynthesis, and nucleocosmochronology.Comment: 47 pages, 2 tables, 11 figures; To appear in PAS

Residence Time Analysis of Rare-Gas Atoms Trapped At A Solid Surface

Recently a model based on an attractive square well and impulsive repulsive potential between a gas and a solid surface has been employed to estimate the fraction of gas atoms trapped in the potential well at the solid surface. A gas atom was considered trapped if it transferred enough energy to the solid (as judged by the thermal accommodation coefficient) to fall into the potential well, i.e., to have negative total energy where the zero of energy is assumed to be the infinitely separated gas atom and solid with the gas atom at rest. The criterion for gas trapping when considering experimental scattering data has been the assumption that the trapped gas is emitted from the surface with a random (cosine) distribution. To assess the possibility that rare-gas atoms may fall into the interatomic well with the metal surface (i.e., be trapped according to the definition of Ref. 1) and still be re-emitted from the surface in a nonrandom distribution, some estimates of surface residence times for the gas should be made. If such a phenomenon as suggested above were to occur, then the calculated trapping probability of the square well model would be expected to be larger than those found experimentally, as has been observed to be the case for krypton and xenon interactions with a tungsten (110) surface. The idea that a gas particle may execute several vibrations at a surface and still not reach thermodynamic equilibrium is not a new one. In this paper the pertinent theory describing this effect is presented, and empirical calculations estimating the magnitude of the effect are presented

The Continuing Slow Decline of AG Pegasi

We analyze optical and ultraviolet observations of the symbiotic binary AG Pegasi acquired during 1992-97. The bolometric luminosity of the hot component declined by a factor of 2-3 from 1980-1985 to 1997. Since 1992, the effective temperature of the hot component may have declined by 10%-20%, but this decline is comparable to the measurement errors. Optical observations of H-beta and He I emission show a clear illumination effect, where high energy photons from the hot component ionize the outer atmosphere of the red giant. Simple illumination models generally account for the magnitude of the optical and ultraviolet emission line fluxes. High ionization emission lines - [Ne V], [Mg V], and [Fe VII] - suggest mechanical heating in the outer portions of the photoionized red giant wind. This emission probably originates in a low density region $\sim$ 30-300 AU from the central binary.Comment: 17 pages, 7 pages, 5 tables; to be published in the Astronomical Journal, July 200