442 research outputs found
Allocation of Foreign Aid in a Segmented International Context
Research on the topic of distribution of foreign aid among recipients is regaining momentum. This is understandable in the light of the knowledge that presently the richest 40 percent of the developing world receives twice as much aid per capita as the poorest 40 percent [UNDP (1994)], while once upon a time foreign aid was sought to accomplish exactly the opposite. The distribution of official development assistance (ODA) is conventionally studied in terms of two models: the ‘recipient needs’ model and the ‘donor interest’ model. In the first, foreign aid flows are seen to satisfy the socio-economic needs of the recipient countries. In the second, national interests of donors, whether these are military, political or commercial, are seen to determine the direction and size of the foreign aid. Empirical studies were made to ascertain and understand whether, on balance, foreign aid is motivated by recipient need or donor interest. There is one class of studies, for example, Mcgillivray (1989), which estimates for donors a compound measure of their allocation bias. The other class of studies, i.e., Maizels and Nissanke (1984) and Grilli and Riess (1992), employs regression analysis to explain allocation of foreign aid by representative variables of recipient need and donor interest. Because the primary pursuit of these studies was to give an overall judgement on foreign aid motivations, insufficient attention was given to differentiations among donors, between recipients, and over time. The allocation policies of donors can be observed to differ between large donors and small donors, whereby the two types of donors are often tied to different groups of recipient countries. Moreover, other arguments than recipient need and donor interest, such as historic and geographical ties and the changing world political order, play important roles.
Economic Growth of Rich and Poor Countries: A Social Accounting Matrix Approach
Many recent empirical studies on comparative growth focus on the supply side determinants of growth. This paper highlights the insights to be gained from employing a demand-determined growth model. A modelling framework along the Social Accounting Matrix, empirically analysed for a group of sixteen countries at different stages of economic development, gives support to the convergence thesis.
High Precision Mass Measurements in and Families Revisited
High precision mass measurements in and families performed
in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited.
The corrections for the new value of the electron mass are presented. The
effect of the updated radiative corrections has been calculated for the
and mass measurements.Comment: 5 pages, 1 table, submitted to Phys. Lett.
Bcc He as a Coherent Quantum Solid
In this work we investigate implications of the quantum nature of bcc %
He. We show that it is a unique solid phase with both a lattice structure and
an Off-Diagonal Long Range Order of coherently oscillating local electric
dipole moments. These dipoles arise from the local motion of the atoms in the
crystal potential well, and oscillate in synchrony to reduce the dipolar
interaction energy. The dipolar ground-state is therefore found to be a
coherent state with a well defined global phase and a three-component complex
order parameter. The condensation energy of the dipoles in the bcc phase
stabilizes it over the hcp phase at finite temperatures. We further show that
there can be fermionic excitations of this ground-state and predict that they
form an optical-like branch in the (110) direction. A comparison with
'super-solid' models is also discussed.Comment: 12 pages, 8 figure
Z^* Resonances: Phenomenology and Models
We explore the phenomenology of, and models for, the Z^* resonances, the
lowest of which is now well established, and called the Theta. We provide an
overview of three models which have been proposed to explain its existence
and/or its small width, and point out other relevant predictions, and potential
problems, for each. The relation to what is known about KN scattering,
including possible resonance signals in other channels, is also discussed.Comment: 29 pages, uses RevTeX4; expanded version (published form
Chiral perturbation theory calculation for pn -> dpipi at threshold
We investigate the reaction pn -> dpipi in the framework of Chiral
Perturbation Theory. For the first time a complete calculation of the leading
order contributions is presented. We identify various diagrams that are of
equal importance as compared to those recognized in earlier works. The diagrams
at leading order behave as expected by the power counting. Also for the first
time the nucleon-nucleon interaction in the initial, intermediate and final
state is included consistently and found to be very important. This study
provides a theoretical basis for a controlled evaluation of the non-resonant
contributions in two-pion production reactions in nucleon-nucleon collisions.Comment: 24 pages, 3 figures, 3 table
Theory of Coexistence of Superconductivity and Ferroelectricity : A Dynamical Symmetry Model
We propose and investigate a model for the coexistence of Superconductivity
(SC) and Ferroelectricity (FE) based on the dynamical symmetries for
the pseudo-spin SC sector, for the displaced oscillator FE sector, and
for the composite system. We assume a minimal
symmetry-allowed coupling, and simplify the hamiltonian using a double mean
field approximation (DMFA). A variational coherent state (VCS) trial
wave-function is used for the ground state: the energy, and the relevant order
parameters for SC and FE are obtained. For positive sign of the SC-FE coupling
coefficient, a non-zero value of either order parameter can suppress the other
(FE polarization suppresses SC and vice versa). This gives some support to
"Matthias' Conjecture" [1964], that SC and FE tend to be mutually exclusive.
For such a Ferroelectric Superconductor we predict: a) the SC gap
(and ) will increase with increasing applied pressure when pressure
quenches FE as in many ferroelectrics, and b) the FE polarization will increase
with increaesing magnetic field up to . The last result is equivalent to
the prediction of a new type of Magneto-Electric Effect in a coexistent SC-FE
material. Some discussion will be given of the relation of these results to the
cuprate superconductors.Comment: 46 page
High-dimensional interior crisis in the Kuramoto-Sivashinsky equation
An investigation of interior crisis of high dimensions in an extended spatiotemporal system exemplified by the Kuramoto-Sivashinsky equation is reported. It is shown that unstable periodic orbits and their associated invariant manifolds in the Poincaré hyperplane can effectively characterize the global bifurcation dynamics of high-dimensional systems.A. C.-L. Chian, E. L. Rempel, E. E. Macau, R. R. Rosa, and F. Christianse
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