AGRICULTURAL POLICY DEVELOPMENTS IN THE UNITED STATES: 1991-93

Agricultural and Food Policy,

TRENDS AND DEVELOPMENTS IN UNITED STATES AGRICULTURAL POLICY: 1993-1995

A number of factors including budget pressures, emphasis on environmentally sensitive agriculture, emphasis on finding agricultural export markets, and anti-agricultural program sentiment have fueled a climate for change in United States agricultural policy. Whether significant changes will occur depends on the political strength of agricultural interest groups and on the compromises which can be reached between them. Several notable achievements have been accomplished in recent domestic agricultural policy legislation. The 1995 farm bill will define the commodity and conservation programs for the next five years. In addition to domestic developments, there have been history-setting accomplishments in reducing barriers to international agricultural trade. The tri-partite North American Free Trade Agreement became effective January 1, 1994. The Uruguay Round Agreement of the General Agreement on Tariffs and Trade was completed in late 1994 and will become effective in 1995.Agricultural and Food Policy,

Near-field spectra of quantum well excitons with non-Markovian phonon scattering

The excitonic absorption spectrum for a disordered quantum well in presence of exciton-acoustic phonon interaction is treated beyond the Markov approximation. Realistic disorder exciton states are taken from a microscopic simulation, and the deformation potential interaction is implemented. The exciton Green's function is solved with a self energy in second order Born quality. The calculated spectra differ from a superposition of Lorentzian lineshapes by enhanced inter-peak absorption. This is a manifestation of pure dephasing which should be possible to measure in near-field experiments.Comment: 8 pages, 7 figure

Observation of soliton explosions in a passively mode-locked fiber laser

Soliton explosions are among the most exotic dissipative phenomena studied in mode-locked lasers. In this regime, a dissipative soliton circulating in the laser cavity experiences an abrupt structural collapse, but within a few roundtrips returns to its original quasi-stable state. In this work we report on the first observation of such events in a fiber laser. Specifically, we identify clear explosion signatures in measurements of shot-to-shot spectra of an Yb-doped mode-locked fiber laser that is operating in a transition regime between stable and noise-like emission. The comparatively long, all-normal-dispersion cavity used in our experiments also permits direct time-domain measurements, and we show that the explosions manifest themselves as abrupt temporal shifts in the output pulse train. Our experimental results are in good agreement with realistic numerical simulations based on an iterative cavity map.Comment: 5 pages, 5 figures, submitte

Character Surfacing and Feathering for UFO

This thesis focuses on the methods used to create the look of the unusual flying ostrich in UFO, a short, stylized film about an earthbound bird with his head in the clouds. That this aspiring aviator is not an ordinary ostrich is visibly indicated by his unusual markings, reflecting his unusual mindset that allows him to achieve the impossible. The techniques used to accomplish the final appearance of the unusual ostrich will be explored in this thesis, with a particular focus on the methods used to create and style the feathers, and the techniques used to hand paint the assorted markings on the character

On ultrafast magnetic flux dendrite propagation into thin superconducting films

We suggest a new theoretical approach describing the velocity of magnetic flux dendrite penetration into thin superconducting films. The key assumptions for this approach are based upon experimental observations. We treat a dendrite tip motion as a propagating flux jump instability. Two different regimes of dendrite propagation are found. A fast initial stage is followed by a slow stage, which sets in as soon as a dendrite enters into the vortex-free region. We find that the dendrite velocity is inversely proportional to the sample thickness. The theoretical results and experimental data obtained by a magneto-optic pump-probe technique are compared and excellent agreement between the calculations and measurements is found.Comment: 4 pages, 4 figure