538 research outputs found
The Case for Mandatory Ownership Disclosure
The use of equity derivatives to conceal economic ownership of shares (âhidden ownershipâ) is increasingly drawing attention from the financial community, as is the exercise of voting power without corresponding economic interest (âempty votingâ). Market participants and commentators have called for expansion of ownership disclosure rules, and policymakers on both sides of the Atlantic are now contemplating how to respond. Yet, in order to design appropriate responses it is key to understand why we have ownership disclosure rules in the first place. This understanding currently appears to be lacking, which may explain why we observe divergent approaches between countries. The case for mandatory ownership disclosure has also received remarkably little attention in the literature, which has focused almost exclusively on mandatory issuer disclosure. Perhaps this is because most people assume that ownership disclosure is a good thing. But why is such information important, and to whom? This paper aims to answer these fundamental questions, using the European disclosure regime as an example. First, the paper identifies two main objectives of ownership disclosure: improving market efficiency and corporate governance. Next, the paper explores the various mechanisms through which ownership disclosure performs these tasks. This sets the stage for an analysis of hidden ownership and empty voting that demonstrates why these phenomena are so problematic.ownership disclosure; market efficiency; corporate governance; monitoring; hidden ownership; empty voting; hedge fund activism
Modelling dependencies in genetic-marker data and its application to haplotype analysis
The objective of this thesis is to develop new methods to reconstruct haplotypes from phaseunknown
genotypes. The need for new methodologies is motivated by the increasing availÂŹ
ability of high-resolution marker data for many species. Such markers typically exhibit
correlations, a phenomenon known as Linkage Disequilibrium (LD). It is believed that reÂŹ
constructed haplotypes for markers in high LD can be valuable for a variety of application
areas in population genetics, including reconstructing population history and identifying
genetic disease variantsTraditionally, haplotype reconstruction methods can be categorized according to whether
they operate on a single pedigree or a collection of unrelated individuals. The thesis begins
with a critical assessment of the limitations of existing methods, and then presents a uniÂŹ
fied statistical framework that can accommodate pedigree data, unrelated individuals and
tightly linked markers. The framework makes use of graphical models, where inference
entails representing the relevant joint probability distribution as a graph and then using
associated algorithms to facilitate computation. The graphical model formalism provides
invaluable tools to facilitate model specification, visualization, and inference.Once the unified framework is developed, a broad range of simulation studies are conducted
using previously published haplotype data. Important contributions include demonstrating
the different ways in which the haplotype frequency distribution can impact the accuracy of
both the phase assignments and haplotype frequency estimates; evaluating the effectiveness
of using family data to improve accuracy for different frequency profiles; and, assessing the
dangers of treating related individuals as unrelated in an association study
Complete CFD analysis of a Velocity XL-5 RG with flight-test verification
The Texas A&M Flight Research Laboratory (FRL) recently received delivery of its
newest aircraft, the Velocity XL-5 RG. The Velocity can fly faster than the other aircraft
owned by the FRL and does not have a propeller in the front of the aircraft to disrupt the
air flow. These are definite advantages that make the Velocity an attractive addition to
the FRL inventory to be used in boundary-layer stability and transition control. Possible
mounting locations built into the aircraft for future projects include hard points in the
wings and roof of the fuselage. One of the drawbacks of the aircraft is that it has a
canard ahead of the main wing that could disrupt the incoming flow for a wing glove or
research requiring test pieces mounted to the hard point in the wing. Therefore, it is
necessary to understand the influence the canard and the impact of its wake on the wing
of the aircraft before any in-depth aerodynamic research could be completed on the
aircraft.
A combination of in-flight measurements of the canard wake and Computational
Fluid Dynamics (CFD) were used to provide a clear picture of the flowfield around the
aircraft. The first step of the project consisted of making a 3-D CAD model of the
aircraft. This model was then used for the CFD simulations in Fluent. 2-D, 3-D, inviscid,
and viscous simulations were preformed on the aircraft. A pressure rake was designed to
house a 5-hole probe and 18 Pitot probes that extended forward of the main wing to
measure the location and strength of the canard wake at various flight conditions. There
were five primary test points that were recorded at multiple times over the course of three flights. Once all of the data were collected from the flights, the freestream
conditions became the inputs into the final, 3-D CFD simulations on the aircraft.
The good agreement between the CFD results and the in-flight measurements
provided the necessary verification of the CFD model of the aircraft. These results can
be used in the future planning and execution of experiments involving the Velocity XL-5
RG
The Case for Mandatory Ownership Disclosure
The use of equity derivatives to conceal economic ownership of shares (âhidden ownershipâ) is increasingly drawing attention from the financial community, as is the exercise of voting power without corresponding economic interest (âempty votingâ). Market participants and commentators have called for expansion of ownership disclosure rules, and policymakers on both sides of the Atlantic are now contemplating how to respond. Yet, in order to design appropriate responses it is key to understand why we have
ownership disclosure rules in the first place. This understanding currently appears to be lacking, which may explain why we observe divergent approaches between countries. The case for mandatory ownership disclosure has also received remarkably little attention in the literature, which has focused almost exclusively on mandatory issuer disclosure. Perhaps this is because most people assume that ownership disclosure is a good thing. But why is such information important, and to whom? This paper aims to answer these fundamental questions, using the European disclosure regime as an example. First, the paper identifies two main objectives of ownership disclosure: improving market efficiency and corporate governance. Next, the paper explores the various mechanisms through which ownership disclosure performs these tasks. This sets the stage for an analysis of hidden ownership and empty voting that demonstrates why these phenomena are so problematic
The Case for Mandatory Ownership Disclosure
The use of equity derivatives to conceal economic ownership of shares (âhidden ownershipâ) is increasingly drawing attention from the financial community, as is the exercise of voting power without corresponding economic interest (âempty votingâ). Market participants and commentators have called for expansion of ownership disclosure rules, and policymakers on both sides of the Atlantic are now contemplating how to respond. Yet, in order to design appropriate responses it is key to understand why we have ownership disclosure rules in the first place. This understanding currently appears to be lacking, which may explain why we observe divergent approaches between countries. The case for mandatory ownership disclosure has also received remarkably little attention in the literature, which has focused almost exclusively on mandatory issuer disclosure. Perhaps this is because most people assume that ownership disclosure is a good thing. But why is such information important, and to whom? This paper aims to answer these fundamental questions, using the European disclosure regime as an example. First, the paper identifies two main objectives of ownership disclosure: improving market efficiency and corporate governance. Next, the paper explores the various mechanisms through which ownership disclosure performs these tasks. This sets the stage for an analysis of hidden ownership and empty voting that demonstrates why these phenomena are so problematic
A capacitance spectroscopy-based platform for realizing gate-defined electronic lattices
Electrostatic confinement in semiconductors provides a flexible platform for
the emulation of interacting electrons in a two-dimensional lattice, including
in the presence of gauge fields. This combination offers the potential to
realize a wide host of quantum phases. Here we present a measurement and
fabrication scheme that builds on capacitance spectroscopy and allows for the
independent control of density and periodic potential strength imposed on a
two-dimensional electron gas. We characterize disorder levels and
(in)homogeneity and develop and optimize different gating strategies at length
scales where interactions are expected to be strong. A continuation of these
ideas might see to fruition the emulation of interaction-driven Mott
transitions or Hofstadter butterfly physics
Rapid and robust association mapping of expression quantitative trait loci
We applied a simple and efficient two-step method to analyze a family-based association study of gene expression quantitative trait loci (eQTL) in a mixed model framework. This two-step method produces very similar results to the full mixed model method, with our method being significantly faster than the full model. Using the Genetic Analysis Workshop 15 (GAW15) Problem 1 data, we demonstrated the value of data filtering for reducing the number of tests and controlling the number of false positives. Specifically, we showed that removing non-expressed genes by filtering on expression variability effectively reduced the number of tests by nearly 50%. Furthermore, we demonstrated that filtering on genotype counts substantially reduced spurious detection. Finally, we restricted our analysis to the markers and transcripts that were closely located. We found five times more signals in close proximity (cis-) to transcripts than in our genome-wide analysis. Our results suggest that careful pre-filtering and partitioning of data are crucial for controlling false positives and allowing detection of genuine effects in genetic analysis of gene expression
Numerical simulations with a first order BSSN formulation of Einstein's field equations
We present a new fully first order strongly hyperbolic representation of the
BSSN formulation of Einstein's equations with optional constraint damping
terms. We describe the characteristic fields of the system, discuss its
hyperbolicity properties, and present two numerical implementations and
simulations: one using finite differences, adaptive mesh refinement and in
particular binary black holes, and another one using the discontinuous Galerkin
method in spherical symmetry. The results of this paper constitute a first step
in an effort to combine the robustness of BSSN evolutions with very high
accuracy numerical techniques, such as spectral collocation multi-domain or
discontinuous Galerkin methods.Comment: To appear in Physical Review
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