Valuation implications of pharmaceutical companies' R&D regulatory approval notifications

This paper examines shareholder wealth effects surrounding applications to, and approvals by, the United States Food and Drug Administration (FDA) for firms listed on the New York (NYSE) and London (LSE) stock exchanges. Applications to the FDA for drug approvals significantly increase shareholder wealth for NYSE firms only. The increase is driven by applications for enhancements to existing drugs, with the market anticipating the application, thus suggesting information leakage. FDA approvals also significantly increase shareholder wealth in both markets. However, there is no evidence of information leakage and the significant post-event abnormal returns support the attention-grabbing hypothesis. Enhanced drug approvals are value-relevant for both markets, which highlights the contribution of real-options to firm value

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

The Origins Behind the Limited Liability Company

This Article documents the story behind the complex origins of the Limited Liability Company (LLC). Using unpublished letters, memoranda, and other documents, this Article shows the inside story of the interest group activity responsible for inventing the first LLC statute in 1977, the initial battle fought by the early LLC proponents to secure partnership classification from the Internal Revenue Service, and the organized efforts of LLC proponents in the 1990s lobbying the IRS for more favorable partnership classification rules, while encouraging the states to enact statutes. Professor Hamill offers a unique perspective on the story of the LLC through her experience as an attorney with the Chief Counsel\u27s Office of the Internal Revenue Service (from 1990-1994) during many of the events described in the Article. This Article also offers insights into the origins of the LLC by analyzing how certain business and tax dynamics came together, resulting in the LLC entering into the American landscape. Focusing on the historical evolution of corporations, this Article traces the LLC\u27s earliest origins to the first few decades of the nineteenth century when state law power over the incorporation process cemented. Focusing on the twentieth century, this Article identifies first the modern income tax of 1913 as the LLC\u27s modern origin, and then explores how the effective income tax burden of doing business in the corporate versus partnership forms and how the development of the markets for investments in independent oil and gas drilling ventures greatly affected the timing of the LLC\u27s invention in the 1970s. An explanation of the LLC\u27s rise to prominence in the 1990s concludes this Article

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 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

An empirical approach to the nucleation of sulfuric acid droplets in the atmosphere

We use quantum mechanical evaluations of the Gibbs free energy of the hydrates of sulfuric acid, H2SO4. nH2O and (H2SO4)2 . nH2O to evaluate an empirical surface tension for sulfuric acid-water clusters containing few molecules. We use this surface tension to evaluate nucleation rates using classical heteromolecular theory. At low temperatures (T 213 K) the nucleation rates obtained with the empirical surface tensions are signifi cantly greater than those using bulk values of the surface tension. At higher temperatures the difference disappears

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

Trends in aerosol abundances and distributions

The properties of aerosols that reside in the upper atmosphere are described. Special emphasis is given to the influence these aerosols have on ozone observation systems, mainly through radiative effects, and on ambient ozone concentrations, mainly through chemical effects. It has long been appreciated that stratospheric particles can interfere with the remote sensing of ozone distribution. The mechanism and magnitude of this interference are evaluated. Separate sections deal with the optical properties of upper atmospheric aerosols, long-term trends in stratospheric aerosols, perturbations of the stratospheric aerosol layer by volcanic eruptions, and estimates of the impacts that such particles have on remotely measured ozone concentrations. Another section is devoted to a discussion of the polar stratospheric clouds (PSC's). These unique clouds, recently discovered by satellite observation, are now thought to be intimately connected with the Antarctic ozone hole. Accordingly, interest in PSC's has grown considerably in recent years. This chapter describes what we know about the morphology, physical chemistry, and microphysics of PSC's

A chloride channel in rat and human axons

Current recordings from single chloride channels were obtained from excised and cell-attached patches of rat and human axons. In rat axons the channels showed an outwardly rectifying current-voltage relationship with a slope conductance of 33 pS at negative membrane potentials and 65 pS at positive potentials (symmetrical 150 mM CsCl). They were measurably for cations (PNa/PCs/PCl=0.1/0.2/1). Channel currents were independent of cytoplasmatic calcium concentration. Inactivation was not observed and gating was weakly voltage dependent. Cl− channels in human axons showed similar gating behavior but had a lower conductance