19,652 research outputs found
The Genesis of Venture Capital - Lessons from the German Experience
Why does venture capital work in some countries but not in others? This clinical study of the first German venture capital firm examines the difficulties of creating a venture capital market in a bank-based financial system. The analysis identifies the problem of creating appropriate governance structures to protect investor returns. It exposes the difficulties of established banks - not to mention government - to devise venture investment strategies. It identifies the availability of high quality entrepreneurs as a critical complement. And it provides a reinterpretation of the hypothesis of Black and Gilson (1997), arguing that the existence of an active stock market is a necessary, but by no means sufficient condition for the development of venture capital.
Corporate Tax Reform and Foreign Direct Investment in Germany – Evidence from Firm-Level Data
Does the reduction of the effective tax burden on corporations trigger foreign direct investment? We take the German tax reform of 2000 as a natural experiment in order to isolate the impact of corporate taxation on the investment of foreign-held affiliates in Germany. We do so by exploiting the very rich MiDi data base from the Deutsche Bundesbank. Although we deliberately choose an approach which is likely to underestimate the tax effects on investment we find significant evidence that the tax reduction had the intended effect of - ceteris paribus - fostering inward direct investment. We find an elasticity of inward foreign direct investment with respect to the effective marginal tax rate of -0.7. We repeat the analysis for different subgroups and find high degrees of heterogeneity. Our results do not allow to decide whether the model of discrete investment choices or the model of marginal adjustment of the capital stock performs better in explaining the investment data.corporate taxation, foreign direct investment
Response functions as quantifiers of non-Markovianity
Quantum non-Markovianity is crucially related to the study of dynamical maps,
which are usually derived for initially factorized system-bath states. We here
demonstrate that linear response theory also provides a way to derive dynamical
maps, but for initially correlated (and in general entangled) states.
Importantly, these maps are always time-translational invariant and allow for a
much simpler quantification of non-Markovianity compared to previous
approaches. We apply our theory to the Caldeira-Leggett model, for which our
quantifier is valid beyond linear response and can be expressed analytically.
We find that a classical Brownian particle coupled to an Ohmic bath can already
exhibit non-Markovian behaviour, a phenomenon related to the initial state
preparation procedure. Furthermore, for a peaked spectral density we
demonstrate that there is no monotonic relation between our quantifier and the
system-bath coupling strength, the sharpness of the peak or the resonance
frequency in the bath.Comment: Updated version with additional information. 5 + 5 pages incl. 2
figures. Comments are welcom
Regenerative neurogenesis: the integration of developmental, physiological and immune signals.
In fishes and salamanders, but not mammals, neural stem cells switch back to neurogenesis after injury. The signalling environment of neural stem cells is strongly altered by the presence of damaged cells and an influx of immune, as well as other, cells. Here, we summarise our recently expanded knowledge of developmental, physiological and immune signals that act on neural stem cells in the zebrafish central nervous system to directly, or indirectly, influence their neurogenic state. These signals act on several intracellular pathways, which leads to changes in chromatin accessibility and gene expression, ultimately resulting in regenerative neurogenesis. Translational approaches in non-regenerating mammals indicate that central nervous system stem cells can be reprogrammed for neurogenesis. Understanding signalling mechanisms in naturally regenerating species show the path to experimentally promoting neurogenesis in mammals
Ionization heating in rare-gas clusters under intense XUV laser pulses
The interaction of intense extreme ultraviolet (XUV) laser pulses
(, \,W/cm) with small rare-gas clusters
(Ar) is studied by quasi-classical molecular dynamics simulations. Our
analysis supports a very general picture of the charging and heating dynamics
in finite samples under short-wavelength radiation that is of relevance for
several applications of free-electron lasers. First, up to a certain photon
flux, ionization proceeds as a series of direct photoemission events producing
a jellium-like cluster potential and a characteristic plateau in the
photoelectron spectrum as observed in [Bostedt {\it et al.}, Phys. Rev. Lett.
{\bf 100}, 013401 (2008)]. Second, beyond the onset of photoelectron trapping,
nanoplasma formation leads to evaporative electron emission with a
characteristic thermal tail in the electron spectrum. A detailed analysis of
this transition is presented. Third, in contrast to the behavior in the
infrared or low vacuum ultraviolet range, the nanoplasma energy capture
proceeds via {\it ionization heating}, i.e., inner photoionization of localized
electrons, whereas collisional heating of conduction electrons is negligible up
to high laser intensities. A direct consequence of the latter is a surprising
evolution of the mean energy of emitted electrons as function of laser
intensity.Comment: figure problems resolve
Is Truth Relevant? On the Relevance of Relevance
An assertion can be a factual claim or the expression of a value judgment. Since Hume the view that these are two incompatible types of assertions that cannot be connected by argumentation, has often been defended, and, more recently, has also been called into question. In the following paper I attempt to show that the truth both of a descriptive sentence and of a normative sentence is derived from its “practical relevance”. The demand that an assertion must be true and must be based on knowledge of the asserter is derived from the demand that an assertion must be practically relevant to the addressee. On the basis of this claim I will sketch a model of what it m
Anomalies and large N limits in matrix string theory
We study the loop expansion for the low energy effective action for matrix
string theory. For long string configurations we find the result depends on the
ordering of limits. Taking before we find free strings.
Reversing the order of limits however we find anomalous contributions coming
from the large limit that invalidate the loop expansion. We then embed the
classical instanton solution into a long string configuration. We find the
instanton has a loop expansion weighted by fractional powers of . Finally we
identify the scaling regime for which interacting long string configurations
have a well defined large limit. The limit corresponds to large "classical"
strings and can be identified with the "dual of the 't Hooft limit,
.Comment: 13 pages, 1 figure, harvmac.tex, notational errors corrected,
references added. Trivial error in section 5 corrected with the result that
the domain of validity of the loop expn. is slightly modifie
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