Transport into the south polar vortex in early spring

Estimates of the mean circulation and diffusive transport of ozone and other species into the Antarctic polar vortex during the spring of 1987 are made using data from the Airborne Antarctic Ozone Experiment. Measurements of long-lived tracers of tropospheric origin remained relatively constant at the levels of the maximum rate of decline of ozone during September. At lower levels in the stratosphere some evidence exists to support intrusions of tropospheric or low latitude air. Given the distribution in latitude and height of these tracers measured from the ER-2 aircraft, it can be inferred that the Lagrangian or diabatic mean circulation was zero or downward over Antarctica during the period of the ozone decline. The observation of a decline in ozone therefore requires a photochemical sink for ozone. The magnitude of the required photochemical sink must be sufficient to offset the transport of ozone into the polar region and produce the observed decline. Quasi-isentropic mixing and downward motion are coupled and are difficult to estimate from a single tracer. The full suite of measured tracers and auxiliary information are brought together to provide an estimate of the rate at which air is cycled through the polar vortex during spring. Estimates of large scale transport of potential vorticity and ozone from previous years are generally consistent with the data from the airborne experiment in suggesting a relatively slow rate of mass flow through the polar vortex in the lower stratosphere during September

Fast Ray Tracing of Lunar Digital Elevation Models

Ray-tracing (RT) of Lunar Digital Elevation Models (DEM)'s is performed to virtually derive the degree of radiation incident to terrain as a function of time, orbital and ephemeris constraints [I- 4]. This process is an integral modeling process in lunar polar research and exploration due to the present paucity of terrain information at the poles and mission planning activities for the anticipated spring 2009 launch of the Lunar Reconnaissance Orbiter (LRO). As part of the Lunar Exploration Neutron Detector (LEND) and Lunar Crater Observation and Sensing Satellite (LCROSS) preparations RI methods are used to estimate the critical conditions presented by the combined effects of high latitude, terrain and the moons low obliquity [5-7]. These factors yield low incident solar illumination and subsequently extreme thermal, and radiation conditions. The presented research uses RT methods both for radiation transport modeling in space and regolith related research as well as to derive permanently shadowed regions (PSR)'s in high latitude topographic minima, e.g craters. These regions are of scientific and human exploration interest due to the near constant low temperatures in PSRs, inferred to be < 100 K. Hydrogen is thought to have accumulated in PSR's through the combined effects of periodic cometary bombardment and/or solar wind processes, and the extreme cold which minimizes hydrogen sublimation [8-9]. RT methods are also of use in surface position optimization for future illumination dependent on surface resources e.g. power and communications equipment

Instantaneous Normal Mode Analysis of Supercooled Water

We use the instantaneous normal mode approach to provide a description of the local curvature of the potential energy surface of a model for water. We focus on the region of the phase diagram in which the dynamics may be described by the mode-coupling theory. We find, surprisingly, that the diffusion constant depends mainly on the fraction of directions in configuration space connecting different local minima, supporting the conjecture that the dynamics are controlled by the geometric properties of configuration space. Furthermore, we find an unexpected relation between the number of basins accessed in equilibrium and the connectivity between them.Comment: 5 pages, 4 figure

An Extended Variational Principle for the SK Spin-Glass Model

The recent proof by F. Guerra that the Parisi ansatz provides a lower bound on the free energy of the SK spin-glass model could have been taken as offering some support to the validity of the purported solution. In this work we present a broader variational principle, in which the lower bound, as well as the actual value, are obtained through an optimization procedure for which ultrametic/hierarchal structures form only a subset of the variational class. The validity of Parisi's ansatz for the SK model is still in question. The new variational principle may be of help in critical review of the issue.Comment: 4 pages, Revtex

Thermodynamics, Structure, and Dynamics of Water Confined between Hydrophobic Plates

We perform molecular dynamics simulations of 512 water-like molecules that interact via the TIP5P potential and are confined between two smooth hydrophobic plates that are separated by 1.10 nm. We find that the anomalous thermodynamic properties of water are shifted to lower temperatures relative to the bulk by $\approx 40$ K. The dynamics and structure of the confined water resemble bulk water at higher temperatures, consistent with the shift of thermodynamic anomalies to lower temperature. Due to this $T$ shift, our confined water simulations (down to $T = 220$ K) do not reach sufficiently low temperature to observe a liquid-liquid phase transition found for bulk water at $T\approx 215$ K using the TIP5P potential. We find that the different crystalline structures that can form for two different separations of the plates, 0.7 nm and 1.10 nm, have no counterparts in the bulk system, and discuss the relevance to experiments on confined water.Comment: 31 pages, 14 figure

First-order transitions for some generalized XY models

In this note we demonstrate the occurrence of first-order transitions in temperature for some recently introduced generalized XY models, and also point out the connection between them and annealed site-diluted (lattice-gas) continuous-spin models

Interface Roughening in a Hydrodynamic Lattice-Gas Model with Surfactant

Using a hydrodynamic lattice-gas model, we study interface growth in a binary fluid with various concentrations of surfactant. We find that the interface is smoothed by small concentrations of surfactant, while microemulsion droplets form for large surfactant concentrations. To assist in determining the stability limits of the interface, we calculate the change in the roughness and growth exponents $\alpha$ and $\beta$ as a function of surfactant concentration along the interface.Comment: 4 pages with 4 embedded ps figures. Requires psfig.tex. Will appear in PRL 14 Oct 199

Fargo: Seeing the significance of style in television poetics?

This article explores the adaptation of the original film to television and how a strain of art or independent cinema contributed to the development of the first series of Fargo (2014–present). By making this comparison, the transition to television of the storyworld established by the Coen brothers raises questions about who is talking in the TV drama – the Coens or makers of the series. At the same time, Fargo can be more easily explained and understood as a strategy by writers, directors and producers that further complicate ideas to do with Noah Hawley, as its showrunner and the show’s single-author status. In Fargo, fidelity to the Coen brothers as a testament to the memory of the original film is set against questions about the reliability of storytelling using complex imagery. By alternating between different levels of narration signified by its stylistic tonal qualities, Fargo succeeds in producing multiple meanings, representations and effects that call attention to textual pleasures in the complex television series