2,324 research outputs found
Wer den Kodex nicht einhÀlt, den bestraft der Kapitalmarkt?
Seit der EinfĂŒhrung des Deutschen Corporate Governance Kodex (Kodex) im Jahr 2002 sind deutsche börsennotierte Unternehmen zur Abgabe der EntsprechenserklĂ€rung gemÀà § 161 AktG verpflichtet (Comply-or-Explain-Prinzip). Auf der Basis dieser Information soll durch den Druck des Kapitalmarkts die Einhaltung des Kodex ĂŒberwacht und gegebenenfalls sanktioniert werden. Dabei wird regelmĂ€Ăig postuliert, dass bei ĂŒberdurchschnittlicher Befolgung bzw. Nichtbefolgung der Kodex-Empfehlungen eine Belohnung durch KurszuschlĂ€ge bzw. eine Sanktionierung durch KursabschlĂ€ge erfolgt. Die Ergebnisse einer Ereignisstudie zeigen, dass die Abgabe der EntsprechenserklĂ€rung keine erhebliche Kursbeeinflussung auslöst und die fĂŒr das Enforcement des Kodex angenommene (und erforderliche) Selbstregulierung durch den Kapitalmarkt nicht stattfindet. Es wird daher kritisch hinterfragt, ob der fĂŒr den Kodex gewĂ€hlte und grundsĂ€tzlich zu begrĂŒĂende flexible Regulierungsansatz im System des zwingenden deutschen Gesellschaftsrechts einen geeigneten Enforcement-Mechanismus darstellt. This paper studies the short-run announcement effects of compliance with the German Corporate Governance Code (âthe Codeâ) on firm value. Event study results suggest that firm value is unaffected by the announcement, although such market reactions to the first time disclosure of the declaration of conformity were widely assumed by the private and public promoters of the Code. This result from acceptance of the German Code add evidence to the hypothesis that regulatory corporate governance initiatives that rely on mandatory disclosure without monitoring and enforcement are ineffective in civil law countries.This paper studies the short-run announcement effects of compliance with the German Corporate Governance Code (âthe Codeâ) on firm value. Event study results suggest that firm value is unaffected by the announcement, although such market reactions to the first time disclosure of the declaration of conformity were widely assumed by the private and public promoters of the Code. This result from acceptance of the German Code add evidence to the hypothesis that regulatory corporate governance initiatives that rely on mandatory disclosure without monitoring and enforcement are ineffective in civil law countries
Inelastic quantum transport in superlattices: success and failure of the Boltzmann equation
Electrical transport in semiconductor superlattices is studied within a fully
self-consistent quantum transport model based on nonequilibrium Green
functions, including phonon and impurity scattering. We compute both the drift
velocity-field relation and the momentum distribution function covering the
whole field range from linear response to negative differential conductivity.
The quantum results are compared with the respective results obtained from a
Monte Carlo solution of the Boltzmann equation. Our analysis thus sets the
limits of validity for the semiclassical theory in a nonlinear transport
situation in the presence of inelastic scattering.Comment: final version with minor changes, to appear in Physical Review
Letters, sceduled tentatively for July, 26 (1999
Hyper-velocity impact test and simulation of a double-wall shield concept for the Wide Field Monitor aboard LOFT
The space mission LOFT (Large Observatory For X-ray Timing) was selected in
2011 by ESA as one of the candidates for the M3 launch opportunity. LOFT is
equipped with two instruments, the Large Area Detector (LAD) and the Wide Field
Monitor (WFM), based on Silicon Drift Detectors (SDDs). In orbit, they would be
exposed to hyper-velocity impacts by environmental dust particles, which might
alter the surface properties of the SDDs. In order to assess the risk posed by
these events, we performed simulations in ESABASE2 and laboratory tests. Tests
on SDD prototypes aimed at verifying to what extent the structural damages
produced by impacts affect the SDD functionality have been performed at the Van
de Graaff dust accelerator at the Max Planck Institute for Nuclear Physics
(MPIK) in Heidelberg. For the WFM, where we expect a rate of risky impacts
notably higher than for the LAD, we designed, simulated and successfully tested
at the plasma accelerator at the Technical University in Munich (TUM) a
double-wall shielding configuration based on thin foils of Kapton and
Polypropylene. In this paper we summarize all the assessment, focussing on the
experimental test campaign at TUM.Comment: Proc. SPIE 9144, Space Telescopes and Instrumentation 2014:
Ultraviolet to Gamma Ray, 91446
Tunneling magneto thermo power in magnetic tunnel junction nanopillars
We study the tunneling magneto thermo power (TMTP) in CoFeB/MgO/CoFeB
magnetic tunnel junction nanopillars. Thermal gradients across the junctions
are generated by a micropatterned electric heater line. Thermo power voltages
up to a few tens of \muV between the top and bottom contact of the nanopillars
are measured which scale linearly with the applied heating power and hence with
the applied temperature gradient. The thermo power signal varies by up to 10
\muV upon reversal of the relative magnetic configuration of the two CoFeB
layers from parallel to antiparallel. This signal change corresponds to a large
spin-dependent Seebeck coefficient of the order of 100 \muV/K and a large TMTP
change of the tunnel junction of up to 90%.Comment: Revised version containing additional data and analyis. 13 pages, 3
figure
Postulates for Revocation Schemes
In access control frameworks with the possibility of delegating
permissions and administrative rights, delegation chains can form. There
are di erent ways to treat these delegation chains when revoking rights,
which give rise to di erent revocation schemes. Hagstr om et al. [11] proposed
a framework for classifying revocation schemes, in which the di erent
revocation schemes are de ned graph-theoretically. At the outset, we identify
multiple problems with Hagstr om et al.'s de nitions of the revocation
schemes, which can pose security risks. This paper is centered around the
question how one can systematically ensure that improved de nitions of the
revocation schemes do not lead to similar problems. For this we propose to
apply the axiomatic method originating in social choice theory to revocation
schemes. Our use of the axiomatic method resembles its use in belief revision
theory. This means that we de ne postulates that describe the desirable behaviour
of revocation schemes, study which existing revocation frameworks
satisfy which postulates, and show how all de ned postulates can be satis ed
by de ning the revocation schemes in a novel way
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