Observations of stratospheric temperature changes coincident with the recent Antarctic ozone depletions

A high degree of correlation between the recent decline in Antarctic total ozone and cooling of the stratosphere during Austral spring has been noted in several recent studies (e.g., Sekiguchi, 1986; Angel, 1986). This study analyzes the observed temperature trends in detail, focusing on the spatial and temporal aspects of the observed cooling. Ozone losses and stratospheric cooling can be correlated for several reasons: (1) ozone losses (from an unspecified cause) will directly reduce temperatures due to decreased solar ultraviolet absorption (Shine, 1986), and/or (2) changes in both ozone and temperature structure due to modification of stratospheric circulation patterns (Mahlman and Fels, 1986). In order to scrutinize various ozone depletion scenarios, detailed information on the observed temperature changes is necessary; the goal is to provide such data. The data used are National Meteorological Center (NMC) Climate Analysis Center (CAC) derived temperatures, covering 1000 to 1 mb (0 to 48 km), for the period 1979 to 1987. Discussions on data origin and quality (assessed by extensive comparisons with radiosonde observations), along with other details of these observations, can be found in Newman and Randel (1988)

Optimal Dynamic Soaring for Full Size Sailplanes

Dynamic soaring is a unique flying technique designed to allow air vehicles to extract energy from horizontal wind shears. Dynamic soaring has been used by seabirds like the Albatross to fly hundreds of kilometers a day across the ocean. Small hobby radio controlled sailplanes have also used this technique to achieve sustained speeds of over 200 miles per hour from just a simple hand toss. Dynamic soaring, however, has never before been studied for use on full size aircraft. The primary goal of this research was to prove or disprove the viability of dynamic soaring for enhancing a full size aircraft\u27s total energy by using a manned sailplane as a demonstration air vehicle. The results of this study will have a direct impact on the sport of soaring, as well as the design of the next generation of large, sailplane-like, robotic planetary explorers for the National Aeronautics and Space Administration (NASA). This research began with a point mass optimization study of an L-23 Super Blanik sailplane. The primary goal of this study was to develop and analyze optimal dynamic soaring trajectories for full size sailplanes. A prototype 6 degrees of freedom (DOF) flight simulator was then developed at the Air Force Research Laboratory\u27s Aerospace Vehicles Technology Assessment and Simulation Branch (AFRL/VACD) and implemented on their Large Amplitude Multi-Mode Aerospace Research Simulator (LAMARS). This simulator helped to validate the dynamic soaring aircraft equations of motion derived for this research and built operational simulator development experience. This experience was then incorporated into a full dynamic soaring research simulator developed at the NASA Dryden Flight Research Facility (NASA DFRC). This NASA simulator was used to develop advanced dynamic soaring flight displays, flight test techniques, and aircrew coordination procedures. Flight test were successfully accomplished using an Super Blanik sailplane and advanced weather monitoring equipment

Aspects of emergent geometry in the AdS/CFT context

We study aspects of emergent geometry for the case of orbifold superconformal field theories in four dimensions, where the orbifolds are abelian within the AdS/CFT proposal. In particular, we show that the realization of emergent geometry starting from the N=4 SYM theory in terms of a gas of particles in the moduli space of vacua of a single D3 brane in flat space gets generalized to a gas of particles on the moduli space of the corresponding orbifold conformal field theory (a gas of D3 branes on the orbifold space). Our main purpose is to show that this can be analyzed using the same techniques as in the N=4 SYM case by using the method of images, including the measure effects associated to the volume of the gauge orbit of the configurations. This measure effect gives an effective repulsion between the particles that makes them condense into a non-trivial vacuum configuration, and it is exactly these configurations that lead to the geometry of X in the AdS x X dual field theoryComment: 24 page

Variability in upwelling across the tropical tropopause and correlations with tracers in the lower stratosphere

Temporal variability of the upwelling near the tropical tropopause on daily to annual timescales is investigated using three different estimates computed from the ERA-Interim reanalysis. These include upwelling archived by the reanalysis, plus estimates derived from thermodynamic and momentum balance calculations. Substantial variability in upwelling is observed on both seasonal and sub-seasonal timescales, and the three estimates show reasonably good agreement. Tropical upwelling should exert strong influence on temperatures and on tracers with large vertical gradients in the lower stratosphere. We test this behavior by comparing the calculated upwelling estimates with observed temperatures in the tropical lower stratosphere, and with measurements of ozone and carbon monoxide (CO) from the Aura Microwave Limb Sounder (MLS) satellite instrument. Time series of temperature, ozone and CO are well correlated in the tropical lower stratosphere, and we quantify the influence of tropical upwelling on this joint variability. Strong coherent annual cycles observed in each quantity are found to reflect the seasonal cycle in upwelling. Statistically significant correlations between upwelling, temperatures and tracers are also found for sub-seasonal timescales, demonstrating the importance of upwelling in forcing transient variability in the lower tropical stratosphere

THREE DIETARY PROTEIN LEVELS IN THE PRODUCTION OF SQUAB BROILERS

THREE DIETARY PROTEIN LEVELS IN THE PRODUCTION OF SQUAB BROILER

Changes in Pelvic Area and Cervical Dilation Near Parturition in Brahman Cows and First-Calf Heifers

Last updated: 6/1/200

Relationships Between Physical Measurements and Calving Difficulty in Two-Year-Old Santa Gertrudis Heifers

Last updated: 6/1/200

Effect of Uterine Manipulation on Postcalving Fertility of Brahman Cows and First-Calf Heifers

Last updated: 6/1/200

Numerical tests of AdS/CFT at strong coupling

We study various correlation functions (two and three point functions) in a large $N$ matrix model of six commuting matrices with a numerical Monte Carlo algorithm. This is equivalent to a model of a gas of particles in six dimensions with a confining quadratic potential and logarithmic repulsions at finite temperature, where we are measuring the leading order non-gaussianities in the thermal fluctuations. This is a simplified model of the low energy dynamics of N=4 SYM at strong coupling. We find strong evidence that the simplified matrix model matches with the dual gravitational description of three point functions in the AdS/CFT correspondence.Comment: 23 pages, 7 figures, revtex. v2: minor correction