Proceedings of a Workshop on Polar Stratospheric Clouds: Their Role in Atmospheric Processes

The potential role of polar stratospheric clouds in atmospheric processes was assessed. The observations of polar stratospheric clouds with the Nimbus 7 SAM II satellite experiment were reviewed and a preliminary analysis of their formation, impact on other remote sensing experiments, and potential impact on climate were presented. The potential effect of polar stratospheric clouds on climate, radiation balance, atmospheric dynamics, stratospheric chemistry and water vapor budget, and cloud microphysics was assessed. Conclusions and recommendations, a synopsis of materials and complementary material to support those conclusions and recommendations are presented

CPA\u27s guide to benefit plans for small business

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Valuation Of The Embedded Option In A Non-Cancelable Lease: Theory And Application

This paper applies a “real” option literature based model to valuing the option element of a non-cancelable lease without an early exercise provision. The model is applied to a common lease type – the closed-end automobile lease. The findings show that the value of the option inherent in an automobile lease is approximately two to six percent of the original asset cost. The analysis discusses ways in which the option value can be captured through the lease contract terms. Management decision makers can use these concepts in evaluating lease/purchase decisions

ECONOMIC SURVIVABILITY OF MISSISSIPPI RICE FARMS: A DETERMINISTIC SIMULATION APPROACH

This study evaluates the economic survivability of rice farms in the Delta area of Mississippi. A general whole-farm simulation model, FLIPSIM V, is used to simulate the operations of representative rice farms over a 10-year period. Although farm size did not change for any of the representative farms considered, the financial structure of these farms changed considerably. Crop mix was found to cause significant differences in the economic growth and financial viability of rice farms in the region.Crop Production/Industries,

The NASA-Ames Research Center stratospheric aerosol model. 2. Sensitivity studies and comparison with observatories

Sensitivity tests were performed on a one-dimensional, physical-chemical model of the unperturbed stratospheric aerosols, and model calculations were compared with observations. The tests and comparisons suggest that coagulation controls the particle number mixing ratio, although the number of condensation nuclei at the tropopause and the diffusion coefficient at high altitudes are also important. The sulfur gas source strength and the aerosol residence time are much more important than the supply of condensation nuclei in establishing mass and large particle concentrations. The particle size is also controlled mainly by gas supply and residence time. In situ observations of the aerosols and laboratory measurements of aerosols, parameters that can provide further information about the physics and chemistry of the stratosphere and the aerosols found there are provided

The Effect of Repeal of the Capital Gain Preference on Venture-Backed Companies

The 1986 Tax Reform Act eliminated preferential tax treatment of capital gains. Proposals to reinstate the preference suggest that risky new investment will suffer without favorable treatment of investment returns. Others have argued that capital for risky new ventures is largely supplied by tax-exempt institutions, who are expected to be indifferent to the taxation of realized gains. This study evaluates the effects of the repeal of preferential capital gains taxation on venture backed firms. The results show negative abnormal returns for sample firms following the Senate’s vote to repeal the capital gain preference. The returns were more negative for firms with a high debt-to-assets ratio, suggesting a more adverse effect for firms relying on equity finance for future capital needs. Sample firms were expected to be particularly sensitive to the tax change, and the results may not be generalizable to other forms of risky investment

The NASA-AMES Research Center Stratospheric Aerosol Model. 1. Physical Processes and Computational Analogs

A time-dependent one-dimensional model of the stratospheric sulfate aerosol layer is presented. In constructing the model, a wide range of basic physical and chemical processes are incorporated in order to avoid predetermining or biasing the model predictions. The simulation, which extends from the surface to an altitude of 58 km, includes the troposphere as a source of gases and condensation nuclei and as a sink for aerosol droplets. The size distribution of aerosol particles is resolved into 25 categories with particle radii increasing geometrically from 0.01 to 2.56 microns such that particle volume doubles between categories

Characterization of the Sea Urchin Major Vault Protein: A Possible Role for Vault Ribonucleoprotein Particles in Nucleocytoplasmic Transport

AbstractVaults are large ribonucleoprotein particles that have been identified in a wide range of eukaryotic organisms. Although present in thousands of copies per cell, their function remains unknown. In this report, we identify the major vault protein in sea urchins as a 107-kDa polypeptide that copurifies with microtubules and ribosomes. Although initially identified in microtubule preparations, the sea urchin major vault protein is not predominantly microtubule-associatedin vivo.Rather, the sea urchin major vault protein is present throughout the cytoplasm in eggs and embryos and in the nucleus in adult somatic cells. Within the nucleus, the sea urchin major vault protein is concentrated in the region of the nucleolus and to punctate regions of the nuclear envelope. In addition, the vault protein localizes to short linear strings juxtaposed to the exterior of the nucleus and extending outward into the cytoplasm. Based on their copurification and intracellular distribution, vaults may be involved in the nucleocytoplasmic transport of ribosomes and/or mRNA

Research Notes : Increasing phytophthora-rot severity in field screening

Walters and Caviness (1968) reported that phytophthora-susceptible varieties in Arkansas were more prone to the disease than resistant varieties if sprayed with 2,4-DB at flowering time. This increase in disease severity suggests that 2,4-D8 could be used to increase the effectiveness of natural and mass selection (cf. Buzzell and Haas, 1972) for disease resistance/tolerance to Phytophthora megaspenna var. sojae (Pms). A non-replicated observation test was established in a field known to be infested with Pms races 3, 7 and 9 (T. R. Anderson, unpublished results) at the Soils Substation, Woodslee, Ontario

Stratospheric aerosol modification by supersonic transport operations with climate implications

The potential effects on stratospheric aerosois of supersonic transport emissions of sulfur dioxide gas and submicron size soot granules are estimated. An interactive particle-gas model of the stratospheric aerosol is used to compute particle changes due to exhaust emissions, and an accurate radiation transport model is used to compute the attendant surface temperature changes. It is shown that a fleet of several hundred supersonic aircraft, operating daily at 20 km, could produce about a 20% increase in the concentration of large particles in the stratosphere. Aerosol increases of this magnitude would reduce the global surface temperature by less than 0.01 K