12,874 research outputs found
The Determinants Of Cross-Border Equity Flows
We apply a new approach to a new panel data set on bilateral gross cross-border equity flows between 14 countries, 1989-96. The remarkably good results have strong implications for theories of asset trade. We find that the geography of information heavily determines the pattern of international transactions. Our model integrates elements of the finance literature on portfolio composition and the international macroeconomics and asset trade literature. Gross asset flows depend on market size in both source and destination country as well as trading costs, in which both information and the transaction technology play a role. The resulting augmented 'gravity' equation has equity market capitalisation representing market size and distance proxying some informational asymmetries, as well as a variable representing openness of each economy. But other variables explicitly represent information transmission (telephone call traffic and multinational bank branches), an information asymmetry between domestic and foreign investors (degree of insider trading), and the efficiency of transactions ('financial market sophistication'). This equation accounts for almost 70% of the variance of the transaction flows. Dummy variables (adjacency, language, currency or trade bloc, and a 'major financial centre' effect) do not improve the results, nor does a variable representing destination country stock market returns. The key role of informational asymmetries is confirmed. Our information transmission variables also substantially improve standard gravity equations for trade in goods.Equity flows, cross-border portfolio investment, information asymmetries, gravity model
Exact stationary solutions of the parametrically driven and damped nonlinear Dirac equation
Two exact stationary soliton solutions are found in the parametrically driven and damped nonlinear Dirac equation. The parametric force
considered is a complex ac force. The solutions appear when their frequencies are locked to half the frequency of the parametric force, and
their phases satisfy certain conditions depending on the force amplitude and on the damping coe cient. Explicit expressions for the charge,
the energy, and the momentum of these solutions are provided. Their stability is studied via a variational method using an ansatz with only
two collective coordinates. Numerical simulations con rm that one of the solutions is stable, while the other is an unstable saddle point.
Consequently, the stabilization of damped Dirac solitons can be achieved via time-periodic parametric excitations.Junta de AndalucÃa and Ministerio de EconomÃa y Competitividad of Spain FIS2017-89349-PMinisterio de Ciencia, Innovación y Universidades of Spain PGC2018-093998-BI0
Wavelet Analysis of Inhomogeneous Data with Application to the Cosmic Velocity Field
In this article we give an account of a method of smoothing spatial
inhomogeneous data sets by using wavelet reconstruction on a regular grid in an
auxilliary space onto which the original data is mapped. In a previous paper by
the present authors, we devised a method for inferring the velocity potential
from the radial component of the cosmic velocity field assuming an ideal
sampling. Unfortunately the sparseness of the real data as well as errors of
measurement require us to first smooth the velocity field as observed on a
3-dimensional support (i.e. the galaxy positions) inhomogeneously distributed
throughout the sampled volume. The wavelet formalism permits us to introduce a
minimal smoothing procedure that is characterized by the variation in size of
the smothing window function. Moreover the output smoothed radial velocity
field can be shown to correspond to a well defined theoretical quantity as long
as the spatial sampling support satisfies certain criteria. We argue also that
one should be very cautious when comparing the velocity potential derived from
such a smoothed radial component of the velocity field with related quantities
derived from other studies (e.g : of the density field).Comment: 19 pages, Latex file, figures are avaible under requests, published
in Inverse Problems, 11 (1995) 76
Enterprises in Transition: Macroeconomic Influences on Enterprise Decision-Making and Performance
This paper analyses the theoretical arguments and empirical evidence linking enterprise performance in transition economies to the macroeconomic environment. Macroeconomic instability is traced to the unsustainability of the fiscal-financial and monetary programmes of the state and to regulatory and other failures leading to problems with the solvency of financial institutions. The importance of macroeconomic stability for enterprise performance is documented with a simulation study and by reviewing relevant microeconomic and aggregate empirical evidence from across the world, as well as from the transition economies themselves. Conclusions are reached about the speed of transition, about the synergy between macroeconomic stabilisation and market development and about the creation of institutions for achieving and maintaining macroeconomic stability.
Thermodynamics, transition dynamics, and texturing in polymer-dispersed liquid crystals with mesogens exhibiting a direct isotropic/smectic-A transition
Experimental and modeling/simulation studies of phase equilibrium and growth
morphologies of novel polymer-dispersed liquid crystal (PDLC) mixtures of PS
(polystyrene) and liquid crystals that exhibit a direct isotropic/smectic-A
(lamellar) mesophase transition were performed for PS/10CB (decyl-
cyanobiphenyl) and PS/12CB (dodecyl-cyanobiphenyl). Partial phase diagrams were
determined using polarized optical microscopy (POM) and differential scanning
calorimetry (DSC) for different compositions of both materials, determining
both phase separation (liquid/liquid demixing) and phase ordering
(isotropic/smectic-A transition) temperatures. The Flory-Huggins theory of
isotropic mixing and Maier-Saupe-McMillan theory for smectic-A liquid
crystalline ordering were used to computationally determine phase diagrams for
both systems, showing good agreement with the experimental results. In addition
to thermodynamic observations, growth morphology relations were found depending
on phase transition sequence, quench rate, and material composition. Three
stages of liquid crystal-rich domain growth morphology were observed: spherical
macroscale domain growth ("stage I"), highly anisotropic domain growth ("stage
II"), and sub-micron spheroid domain growth ("stage III"). Nano-scale structure
of spheroidal and spherocylindrical morphologies were then determined via
two-dimensional simulation of a high-order Landau-de Gennes model. Morphologies
observed during stage II growth are typical of di- rect isotropic/smectic-A
phase transitions, such as highly anisotropic "batonnets" and filaments. These
morphologies, which are found to be persistent in direct isotropic/smectic-A
PDLCs, could provide new functionality and applications for these functional
materials.Comment: First Revision, 21 pages, 11 figures, submitted to Macromolecules as
an article 17JUL200
Flavor constraints on electroweak ALP couplings
We explore the signals of axion-like particles (ALPs) in flavor-changing
neutral current (FCNC) processes. The most general effective linear Lagrangian
for ALP couplings to the electroweak bosonic sector is considered, and its
contribution to FCNC decays is computed up to one-loop order. The interplay
between the different couplings opens new territory for experimental
exploration, as analyzed here in the ALP mass range GeV.
When kinematically allowed, decays provide the most
stringent constraints for channels with invisible final states, while -meson
decays are more constraining for visible decay channels, such as displaced
vertices in data. The complementarity with
collider constraints is discussed as well.Comment: 12 pages, 6 figure
Program for the feasibility of developing a high pressure acoustic levitator
This is the final report for the program for the feasibility of developing a high-pressure acoustic levitator (HPAL). It includes work performed during the period from February 15, 1987 to October 26, 1987. The program was conducted for NASA under contract number NAS3-25115. The HPAL would be used for containerless processing of materials in the 1-g Earth environment. Results show that the use of increased gas pressure produces higher sound pressure levels. The harmonics produced by the acoustic source are also reduced. This provides an improvement in the capabilities of acoustic levitation in 1-g. The reported processing capabilities are directly limited by the design of the Medium Pressure Acoustic Levitator used for this study. Data show that sufficient acoustic intensities can be obtained to levitate and process a specimen of density 5 g/cu cm at 1500 C. However, it is recommended that a working engineering model of the HPAL be developed. The model would be used to establish the maximum operating parameters of furnace temperature and sample density
- …