Fluid thrust control system

A pure fluid thrust control system is described for a pump-fed, regeneratively cooled liquid propellant rocket engine. A proportional fluid amplifier and a bistable fluid amplifier control overshoot in the starting of the engine and take it to a predetermined thrust. An ejector type pump is provided in the line between the liquid hydrogen rocket nozzle heat exchanger and the turbine driving the fuel pump to aid in bringing the fluid at this point back into the regular system when it is not bypassed. The thrust control system is intended to function in environments too severe for mechanical controls

Diffractive charged meson pair production

We investigate the possibility to measure the nonforward gluon distribution function by means of diffractively produced \pi^+\pi^- and K^+K^- pairs in polarized lepton nucleon scattering. The resulting cross sections are small and are dominated by the gluonic contribution. We find relatively large spin asymmetries, both for \pi^+\pi^- and for K^+K^- pairs.Comment: 15 pages, version with changed kinematical cuts, to be pubished in Phys.Lett.

Corporate governance in newly listed companies

Topics in corporate governance have been around in the literature almost for a century, most of the theoretical and empirical work has focused on the large and public company. While this research has improved our understanding of how large corporations are governed, corporate governance in small and medium sized enterprises and in particular in entrepreneurial and newly listed firms has rarely been studied. This essay offers a reflective overview of corporate governance mechanisms in entrepreneurial and newly listed companies and of why and how governance mechanisms differ from those in large and publicly traded corporations. In contrast to the traditional approach in corporate governance, we do not rely on the agency perspective as a work-horse to analyze governance problems. Instead we focus on either market or institutional based mechanisms in corporate governance. This opens the view on governance problems in newly listed companies outside the narrow view of either an agency or free-market perspective. Instead, the following study tries to bridge the different perspectives on corporate governance. From the broad set of mechanisms in corporate governance discussed in the literature, we focus only on a small subset which is prevalent in newly listed companies like the product and capital market, the market for corporate control, boards of directors and capital structures

Resolution of Nested Neuronal Representations Can Be Exponential in the Number of Neurons

Collective computation is typically polynomial in the number of computational elements, such as transistors or neurons, whether one considers the storage capacity of a memory device or the number of floating-point operations per second of a CPU. However, we show here that the capacity of a computational network to resolve real-valued signals of arbitrary dimensions can be exponential in N, even if the individual elements are noisy and unreliable. Nested, modular codes that achieve such high resolutions mirror the properties of grid cells in vertebrates, which underlie spatial navigation

The first-mover advantage in scientific publication

Mathematical models of the scientific citation process predict a strong "first-mover" effect under which the first papers in a field will, essentially regardless of content, receive citations at a rate enormously higher than papers published later. Moreover papers are expected to retain this advantage in perpetuity -- they should receive more citations indefinitely, no matter how many other papers are published after them. We test this conjecture against data from a selection of fields and in several cases find a first-mover effect of a magnitude similar to that predicted by the theory. Were we wearing our cynical hat today, we might say that the scientist who wants to become famous is better off -- by a wide margin -- writing a modest paper in next year's hottest field than an outstanding paper in this year's. On the other hand, there are some papers, albeit only a small fraction, that buck the trend and attract significantly more citations than theory predicts despite having relatively late publication dates. We suggest that papers of this kind, though they often receive comparatively few citations overall, are probably worthy of our attention.Comment: 7 pages, 3 figure

Universitäten als regionale Förderer der Wirtschaft?

In diesem Beitrag werden mögliche Einflussfaktoren auf die Standortentscheidung von Unternehmen in der Umgebung von Universitäten aufgezeigt. Dabei wird auf Studien zurückgegriffen, die anhand der am Neuen Markt gelisteten Unternehmen durchgeführt wurden. Als wesentliche Einflussfaktoren auf die Ansiedlung von Unternehmen in räumlicher Nähe zu Universitäten erweisen sich die Anzahl der Studenten sowie die Forschungsleistungen, vor allem im Bereich der Naturwissenschaften. Zudem macht sich für Unternehmen die räumliche Nähe zu einer forschungsintensiven Universität längerfristig in einer überdurchschnittlichen Entwicklung am Aktienmarkt bezahlt.Wirtschaftsförderung; Regionalpolitik; Hochschule; Forschungskooperation; Betriebliche Standortwahl; Standortfaktor

The benefits of family ownership, control and management on financial performance of firms

The benefits of family ownership and control of firms are at the center of the family firm debate. Previous studies have used either family ownership or management as proxies for control. Both indicators are off the mark, as they do not measure decision control as intended by the theory of the firm. This is the first study investigating the direct influence of family ownership, control and management on financial firm performance, while controlling for goal heterogeneity of different stakeholders. Our results clearly show that family control is beneficial for all stakeholders, while neither family ownership nor management influences financial performance. Monitoring behavior of families is the central component and essence of family firms and can be used as a point of departure for the development of a unified theory of family firms

Quasi-Bayesian Nonparametric Density Estimation via Autoregressive Predictive Updates

Bayesian methods are a popular choice for statistical inference in small-data regimes due to the regularization effect induced by the prior. In the context of density estimation, the standard nonparametric Bayesian approach is to target the posterior predictive of the Dirichlet process mixture model. In general, direct estimation of the posterior predictive is intractable and so methods typically resort to approximating the posterior distribution as an intermediate step. The recent development of quasi-Bayesian predictive copula updates, however, has made it possible to perform tractable predictive density estimation without the need for posterior approximation. Although these estimators are computationally appealing, they struggle on non-smooth data distributions. This is due to the comparatively restrictive form of the likelihood models from which the proposed copula updates were derived. To address this shortcoming, we consider a Bayesian nonparametric model with an autoregressive likelihood decomposition and a Gaussian process prior. While the predictive update of such a model is typically intractable, we derive a quasi-Bayesian update that achieves state-of-the-art results in small-data regimes