Taxes and Corporate Dynamics: The Product-Market Effect.

corporations; taxes;

Quantum clocks are more accurate than classical ones

A clock is, from an information-theoretic perspective, a system that emits information about time. One may therefore ask whether the theory of information imposes any constraints on the maximum precision of clocks. Here we show a quantum-over-classical advantage for clocks or, more precisely, the task of generating information about what time it is. The argument is based on information-theoretic considerations: we analyse how the accuracy of a clock scales with its size, measured in terms of the number of bits that could be stored in it. We find that a quantum clock can achieve a quadratically improved accuracy compared to a purely classical one of the same size.Comment: 17 + 60 pages. V2: corrected typos and improved discussio

Digital infra-red image processing

This paper describes a general approach to the digital processing of infra-red images, from data acquisition to data use. The main steps of this processing are developped . Emphasis is placed on the pre-processing which reduces the systematic radiometric errors and the considerable random noise inherent to infra-red images. It is then shown that, with such a pre processing, classical techniques used for image in the visible domain become practicable . Each process is explained in theory and illustrated with a practical example.Cet article présente une approche générale du traitement numérique des images infrarouges de l'acquisition à l'utilisation des données. Les principales étapes d'un tel traitement y sont développées . L'accent est mis sur les prétraitements qui visent à diminuer les erreurs radiométriques et le fort bruit aléatoire qui caractérisent les images infrarouges . Il est ensuite montré comment l'application de tels prétraitements permet d'utiliser efficacement des méthodes classiquement mises en oeuvre pour des images du domaine visible . Chaque traitement, expliqué d'un point de vue théorique, est illustré par un exemple concret

Microstructural stability of Co-Re-Cr-Ta-C alloy strengthened by TaC precipitates

It is becoming increasingly clear that new materials that can operate at substantially higher temperatures than Ni-base superalloys are needed for future gas turbines. High melting Co-Re-Cr based alloy strengthened by carbides, particularly the MC type carbide, shows promise [1]. A fine dispersion of globular TaC precipitate is exploited for this purpose. Additionally Cr, which is mainly added to improve oxidation resistance, also stabilizes lamellar M23C6 type Cr carbide. The microstructure of a Co-Re-Cr-Ta-C alloy with the two types of carbides is seen in Fig. 1. Please click Additional Files below to see the full abstract

Le portrait de l’investissement responsable au Québec - Résultats de recherche

La composante du capital de développement regroupe les institutions de capital de risque avec multi-objectifs (Economically Targeted Investment). Les catégories les plus importantes sont composées des actifs provenant des fonds de travailleurs et de Capital régional et coopératif Desjardins. Au total, le capital de développement mobilise des actifs de plus de 3,9 milliards de dollars (G$) en investissement à impact économique québécois, bien que nos enquêtes aient permis de catégoriser des actifs atteignant près de 1,5 G$ en 2006 (année de l’enquête pour cette composante; voir explication au chapitre 3). La finance solidaire désigne le financement du développement économique communautaire et des entreprises d’économie sociale. Cette composante de la FSR canalisait des actifs de près de 330 millions $(M$) en 2004 (année de l’enquête pour cette composante). Ces actifs sont principalement canalisés par le financement des entreprises d’économie sociale et dans le logement communautaire et social

Quantum key distribution using gaussian-modulated coherent states

Quantum continuous variables are being explored as an alternative means to implement quantum key distribution, which is usually based on single photon counting. The former approach is potentially advantageous because it should enable higher key distribution rates. Here we propose and experimentally demonstrate a quantum key distribution protocol based on the transmission of gaussian-modulated coherent states (consisting of laser pulses containing a few hundred photons) and shot-noise-limited homodyne detection; squeezed or entangled beams are not required. Complete secret key extraction is achieved using a reverse reconciliation technique followed by privacy amplification. The reverse reconciliation technique is in principle secure for any value of the line transmission, against gaussian individual attacks based on entanglement and quantum memories. Our table-top experiment yields a net key transmission rate of about 1.7 megabits per second for a loss-free line, and 75 kilobits per second for a line with losses of 3.1 dB. We anticipate that the scheme should remain effective for lines with higher losses, particularly because the present limitations are essentially technical, so that significant margin for improvement is available on both the hardware and software.Comment: 8 pages, 4 figure

Mars Sedimentary Geology: Key Concepts and Outstanding Questions

Processes that operate at planetary surfaces have the potential to record a history of planetary evolution in the form of sedimentary rocks. This is important because our experience on Earth shows that sediments and sedimentary rocks are the dominant archive of high-resolution proxies of present and past tectonic, climatic, and biological processes. Our understanding of the evolution of Earth’s very ancient climate and paleobiological records derives from detailed examination of the mineralogical, textural, and geochemical signatures preserved in the sedimentary rock record. Sedimentary rocks were first recognized on Mars less than a decade ago (Malin and Edgett, 2000). Recent interpretations of data collected by the Mars Express and Mars Reconnaissance Orbiter spacecraft have confirmed the surprising abundance of these sedimentary rocks, the past role of water on the martian surface, and the similarity—in some cases—to sedimentary rocks formed on Earth. Thick sulfaterich deposits invite comparison to terrestrial evaporites (Grotzinger et al., 2005). In other cases, clay-rich strata are interpreted as the terminal deposits of source-to-sink systems with well-developed fluvial networks in the upper reaches of watersheds that date back to a much wetter period in Mars’ earliest history (Ehlmann et al., 2008; Metz et al., 2009). However, these Earth-like depositional systems contrast with other deposits that may be unique in the Solar System: for example, vast terrains as large as Earth’s continents covered by thick veneers of strata that may derive entirely from settling out of wind-transported dust (Bridges et al., 2010). Whatever their origin, it is now clear that the sedimentary rocks of Mars represent a new frontier for research. Mars science is in its golden era of exploration—the past decade of orbiter and landed missions has produced an extraordinary amount of new data relevant to the analysis of sediments and sedimentary rocks, and robust international programs exist for future missions. To help stimulate discussion of these data, the First International Conference on Mars Sedimentology and Stratigraphy was convened in El Paso, Texas, in April 2010. The contents of this white paper represent the most significant findings of the conference, with additional information provided by the coauthors, and focus on seven key questions for future investigation by the sedimentary geology community

Quantum properties of the three-mode squeezed operator: triply concurrent parametric amplifiers

In this paper, we study the quantum properties of the three-mode squeezed operator. This operator is constructed from the optical parametric oscillator based on the three concurrent $\chi^{(2)}$ nonlinearities. We give a complete treatment for this operator including the symmetric and asymmetric nonlinearities cases. The action of the operator on the number and coherent states are studied in the framework of squeezing, second-order correlation function, Cauchy-Schwartz inequality and single-mode quasiprobability function. The nonclassical effects are remarkable in all these quantities. We show that the nonclassical effects generated by the asymmetric case--for certain values of the system parameters--are greater than those of the symmetric one. This reflects the important role for the asymmetry in the system. Moreover, the system can generate different types of the Schr\"odinger-cat states.Comment: 21 pages, 14 figures; comments are most welcom