Contributions of the Ornamental Horticulture and Turfgrass Industry to the South Carolina Economy, 1999

Crop Production/Industries,

Propulsion simulation for magnetically suspended wind tunnel models

The feasibility of simulating propulsion-induced aerodynamic effects on scaled aircraft models in wind tunnels employing Magnetic Suspension and Balance Systems. The investigation concerned itself with techniques of generating exhaust jets of appropriate characteristics. The objectives were to: (1) define thrust and mass flow requirements of jets; (2) evaluate techniques for generating propulsive gas within volume limitations imposed by magnetically-suspended models; (3) conduct simple diagnostic experiments for techniques involving new concepts; and (4) recommend experiments for demonstration of propulsion simulation techniques. Various techniques of generating exhaust jets of appropriate characteristics were evaluated on scaled aircraft models in wind tunnels with MSBS. Four concepts of remotely-operated propulsion simulators were examined. Three conceptual designs involving innovative adaptation of convenient technologies (compressed gas cylinders, liquid, and solid propellants) were developed. The fourth innovative concept, namely, the laser-assisted thruster, which can potentially simulate both inlet and exhaust flows, was found to require very high power levels for small thrust levels

Acquisition of prescribing skill by medical students in a problem-based learning curriculum: preclerkship to clerkship phase transition

Background: Medical school training for students in pharmacotherapy is sub-optimal and junior doctors are not confident to prescribe drugs. This study was conducted to assess the prescribing competency of students in preclerkship and clerkship phases at a medical school that implements problem-based learning curriculum.Methods: Objective structured practical examination was used to assess prescribing competency of students in both phases. The prescribing performance was empirically categorized into poor, moderate and good competency.Results: The prescription writing skills achieved by the clerkship students did not significantly differ from that attained by students in preclerkship phase. Good prescribing competency was attained by approximately 20% of the students at the end of both phases. Preclerkship students performed better on therapeutic reasoning than those in clerkship phase. Cognitive skill that involves choosing the superior drug(s) among several alternatives as achieved less satisfactorily by majority of students from both phases of the program.Conclusions: Acquisition and further development of the prescribing competency during the clerkship phase was sub-optimal. The continuation of pharmacotherapeutic context-learning program during clerkship phase is recommended

Stochastic to deterministic crossover of fractal dimension for a Langevin equation

Using algorithms of Higuchi and of Grassberger and Procaccia, we study numerically how fractal dimensions cross over from finite-dimensional Brownian noise at short time scales to finite values of deterministic chaos at longer time scales for data generated from a Langevin equation that has a strange attractor in the limit of zero noise. Our results suggest that the crossover occurs at such short time scales that there is little chance of finite-dimensional Brownian noise being incorrectly identified as deterministic chaos.Comment: 12 pages including 3 figures, RevTex and epsf. To appear Phys. Rev. E, April, 199

Transient band keratopathy associated with ocular inflammation and systemic hypercalcemia

Anat Galor, Henry A Leder, Jennifer E Thorne, James P DunnThe Wilmer Eye Institute, Department of Ophthalmology, the Johns Hopkins University School of MedicinePurpose: To report a case of visually significant band keratopathy associated with ocular inflammation and systemic hypercalcemia which markedly decreased in severity after treatment of these underlying factors.Methods: Retrospective case report.Results: A 53-year-old Asian female with granulomatous panuveitis in the left eye presented with diffuse band keratopathy through the central cornea. The serum calcium was elevated. The patient was treated with topical prednisolone acetate 1% and oral prednisone with marked improvement in inflammation. The band keratopathy lessened in severity with clearing of the central cornea and improvement in visual acuity.Conclusions: Early medical treatment of underlying factors may allow reversal of band keratopathy.Keywords: ocular inflammation, transient band keratopath

The Evolution of the Stellar Mass Functions of Star-Forming and Quiescent Galaxies to z = 4 from the COSMOS/UltraVISTA Survey

We present measurements of the stellar mass functions (SMFs) of star-forming and quiescent galaxies to z = 4 using a sample of 95 675 galaxies in the COSMOS/UltraVISTA field. Sources have been selected from the DR1 UltraVISTA K_{s}-band imaging which covers a unique combination of a wide area (1.62 deg^2), to a significant depth (K_{s,tot} = 23.4). The SMFs of the combined population are in good agreement with previous measurements and show that the stellar mass density of the universe was only 50%, 10% and 1% of its current value at z ~ 0.75, 2.0, and 3.5, respectively. The quiescent population drives most of the overall growth, with the stellar mass density of these galaxies increasing by 2.71^{+0.93}_{-0.22} dex since z = 3.5. At z > 2.5, star-forming galaxies dominate the total SMF at all stellar masses, although a nonzero population of quiescent galaxies persists to z = 4. Comparisons of the K_{s}-selected star-forming galaxy SMFs to UV-selected SMFs at 2.5 < z < 4 show reasonable agreement and suggests UV-selected samples are representative of the majority of the stellar mass density at z > 3.5. We estimate the average mass growth of individual galaxies by selecting galaxies at fixed cumulative number density. The average galaxy with Log(M_{*}/M_{sun}) = 11.5 at z = 0.3 has grown in mass by only 0.2 dex (0.3 dex) since z = 2.0(3.5), whereas those with Log(M_{*}/M_{sun}) = 10.5 have grown by > 1.0 dex since z = 2. At z < 2, the time derivatives of the mass growth are always larger for lower-mass galaxies, which demonstrates that the mass growth in galaxies since that redshift is mass-dependent and primarily bottom-up. Lastly, we examine potential sources of systematic uncertainties on the SMFs and find that those from photo-z templates, SPS modeling, and the definition of quiescent galaxies dominate the total error budget in the SMFs.Comment: 18 pages paper, 12 pages appendix, 23 figures. Accepted for publication in the Ap