On the debt Capacityof growth Options

If debt capacity is defined as the incremental debt that is optimally associated with an additional asset, then the debt capacity of growth options is negative. Underinvestment costs of debt increase and free cash flow benefits of debt fall with additional growth options. Thus, if firm value increases with additional growth options, then leverage not only declines, but the firm’s optimal total debt level declines as well. This result implies a negative relation between book leverage and growth options and provides a new economic interpretation of book leverage regressions.Growth options; Book leverage

Comparative study of deuterium retention and vacancy content of self-ion irradiated tungsten

Self-ion irradiation of pure tungsten with 2 MeV W ions provides a way of simulating microstructures generated by neutron irradiation in tungsten components of a fusion reactor. Transmission electron microscopy (TEM) has been used to characterize defects formed in tungsten samples by ion irradiation. It was found that tungsten irradiated to 0.85 dpa at relatively low temperatures develops a characteristic microstructure dominated by dislocation loops and black dots. The density and size distribution of these defects were estimated. Some of the samples exposed to self-ion irradiation were then implanted with deuterium. Thermal Desorption Spectrometry (TDS) analysis was performed to estimate the deuterium inventory as a function of irradiation damage and deuterium release as a function of temperature. Increase of inventory with increasing irradiation dose followed by slight decrease above 0.1 dpa was found. Application of Positron Annihilation Spectroscopy (PAS) to self-irradiated but not deuterium implanted samples enabled an assessment of the density of irradiation defects as a function of exposure to highenergy ions. The PAS results show that the density of defects saturates at doses in the interval from 0.085 to 0.425 displacements per atom (dpa). These results are discussed in the context of recent theoretical simulations exhibiting the saturation of defect microstructure in the high irradiation exposure limit. The saturation of damage found in PAS agrees with the simulation data described in the paper. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )Peer reviewe

Debt Maturity Choices, Multi-stage Investments and Financing Constraints

We develop a dynamic investment options framework with optimal capital structure and analyze the effect of debt maturity. We find that in the absence of financing constraints short-term debt maximizes firm value. In contrast with most literature results, in the absence of constraints, higher volatility may increase initial debt for firms with low initial revenues, issuing long term debt that expires after the investment option maturity. This effect, which is due to the option value of receiving the value of assets and remaining tax savings, does not hold for short term debt and firms with high profitability, where an increase in volatility reduces the firm value. The importance of short-term debt is reduced in the presence of non-negative equity net worth or debt financing constraints and firms behave more conservatively in the use of initial debt. With non-negative equity net worth, higher volatility has adverse effects on the firm value, while with debt financing constraints higher volatility may enhance firm value for firms with relatively low revenue that have out-of-the-money investment options

Resonant multiphoton ionization of caesium atoms

This paper studies the resonant multiphoton ionization (RMPI) phenomenon, in the case of caesium atoms interacting with the intense field of a neodymium-Glass laser. In the first part, we present a recent theory of RMPI, in a simplified form in order to obtain the main informations on the physics of RMPI. Then we present two experiments of RMPI : four-photon ionization of the caesium atom in its ground state, with a three-photon resonance on the 6F level and three-photon ionization of the caesium atom is its 62P3/2 state with a two-photon resonance on the 12F level. In the first experiment, the internal structure of the resonant transition is resolved, enabling us to point out and analyse the important effect of pulse shapes and focusing conditions on our experimental results, which are discussed in detail. We also give some new interpretations of results published previously [1]. In the second experiment, we measure the 12F fine structure — which is found to be (0.016 ± 0.008) cm-1 — and show that we have reached the limits imposed by the Doppler effect. These experimental results are in good agreement with the theoretical predictions suggesting that the physical picture given of RMPI by recent works on this subject is satisfactory.L'objet de cet article est l'étude du phénomène d'ionisation multiphotonique résonnante (IMPR) de l'atome de césium soumis au champ intense d'un laser au verre dopé au néodyme. Une première partie est consacrée à l'exposé d'une théorie récente de l'IMPR, sous une forme simplifiée, pour en tirer les informations essentielles sur la physique de l'IMPR. Nous présentons ensuite deux expériences d'IMPR du césium : ionisation à quatre photons de l'atome de césium dans son état fondamental, avec résonance à trois photons sur le niveau 6F ; ionisation à trois photons de l'atome de césium dans son état 62P3/2 avec résonance à deux photons sur le niveau 12F. Dans la première expérience, on résout la structure fine de la transition résonnante, ce qui permet de mettre en lumière et d'analyser l'effet important des formes d'impulsions et des conditions de focalisation sur nos résultats expérimentaux. Nous donnons aussi des interprétations récentes de certains résultats publiés auparavant [1]. Dans la deuxième expérience, on mesure la structure fine du niveau 12F, qui est trouvée égale à (0,016 ± 0,008) cm-1 et on montre que nous arrivons aux limites imposées par l'effet Doppler. Les résultats de ces expériences sont en bon accord avec les prévisions théoriques, et permettent de considérer comme satisfaisante l'image physique que nous donnent de l'IMPR les récents travaux à ce sujet

On the Debt Capacity of Growth Options

If debt capacity is defined as the incremental debt optimally associated with an additional asset, then the debt capacity of growth options is negative. The underinvestment costs of debt increase and free cash flow benefits of debt fall with additional growth options. Thus, if firm value increases with additional growth options, then not only does leverage decline but the firm's optimal total debt level declines as well. This result implies a negative relation between book leverage and growth options and provides a new economic interpretation of book leverage regressions.

ETUDE EXPERIMENTALE DE L'IONISATION MULTIPHOTONIQUE DES GAZ RARES ET DES ATOMES ALCALINS

Description d'une expérience permettant la mesure des probabilités d'ionisation multiphotonique des gaz rares et des alcalins ainsi que la valeur des ordres de non linéarité des processus. Les résultats semblent confirmer l'hypothèse d'une ionisation en deux étapes, la première portant l'électron sur un niveau dont l'énergie est voisine de celle d'un nombre entier de photons, la seconde le portant dans le continuum.An experiment is discribed allowing the measurement of the multiphoton ionization probabilities of rare gases and of two alkali vapors. The experimental values of the probabilities and of the order of non linearity are given. These results seem to confirm a two stage process hypothesis