1,497 research outputs found
An Economic Analysis of food Policy in the Ivory Coast
Ivory Coast covers an area of 124,000 square miles with reasonable rainfall for food crops production. But besides what has been called the economic miracle, the country relies on increasing food imports (rice, wheat, meat, and milk products). At the same time, the country\u27s earnings from the major export commodities are shrinking. So the primary objective was to identify the main causes and circumstances that have resulted in reductions in food production. The major hypothesis was that the present situation is simply the result of policies that have favored cash crops relative to good products. A formal treatment and an analysis of the institutional and structural setting were made.
The results of the formal treatment showed relatively high trend growth rate in cash crops compared to good products. Some food crops experienced high trend growth rate but exhibited a very erratic pattern in their production. And this seems to support the hypothesis made.
A ministry of Rural Development has been created in November, 1983, and increasing food production is one of its main objectives. However, profound and appropriate studies prior to any move towards total reliance on domestic food production are crucial for the country\u27s resources allocation
Catalysts and Barriers to Foreign Direct Investment in Ghana
Foreign direct investment (FDI) is regarded as the catalyst for the growth of developing economies in recent times. This study investigates the factors influencing the FDI in Ghanaian economy. The study administered questionnaire to twenty two (22) Chief Executive officers of Multinational Companies operating in banking, telecommunication, mining, oil and gas sectors of the Ghanaian economy. The result indicates that several factors influence or inhibit FDI in the economy. Factors that encourage FDI in Ghana include the abundance of natural resources, political stability, availability of cheap labour force, and growing markets. Several barriers were found present and these include, among others, poor ICT infrastructure, volatile exchange rates, lack of reliable supply of water and energy, and poor road network as the very important factors that inhibit inflows of FDI into Ghana
Assessing Univariate and Multivariate Normality, A Guide For Non-Statisticians
Most parametric methods rely on the assumption of normality. Results obtained from these methods are more powerful compared to their non-parametric counterparts. However for valid inference, the assumptions underlying the use of these methods should be satisfied. Many published statistical articles that make use of the assumption of normality fail to guarantee it. Hence, quite a number of published statistical results are presented with errors. As a way to reduce this, various approaches used in assessing the assumption of normality are presented and illustrated in this paper.  In assessing both univariate and multivariate normality, several methods have been proposed. In the univariate setting, the Q-Q plot, histogram, box plot, stem-and-leaf plot or dot plot are some graphical methods that can be used. Also, the properties of the normal distribution provide an alternative approach to assess normality. The Kolmogorov-Smirnov (K-S) test, Lilliefors corrected K-S test, Shapiro-Wilk test, Anderson-Darling test, Cramer-von Mises test, D'Agostino skewness test, Anscombe-Glynn kurtosis test, D'Agostino-Pearson omnibus test, and the Jarque-Bera test are also used to test for normality. However, Kolmogorov-Smirnov (K-S) test, Shapiro-Wilk test, Anderson-Darling test, and Cramer-von Mises test are widely used in practice and implemented in many statistical applications. For multivariate normal data, marginal distribution and linear combinations should also be normal. This provides a starting point for assessing normality in the multivariate setting. A scatter plot for each pair of variables together with a Gamma plot (Chi-squared Q-Q plot) is used in assessing bivariate normality. For more than two variables, a Gamma plot can still be used to check the assumption of multivariate normality. Among the many test proposed for testing multivariate normality, Royston's and Mardia's tests are used more often and are implemented in many statistical packages. When the normality assumption is not justifiable, techniques for non-normal data can be used. Likewise, transformation to near normality is another alternative. Keywords: Univariate normal, Multivariate normal, Q-Q plot, Gamma plot, Kolmogorov-Smirnov test, Shapiro-Wilk test, Mardia's test, Royston's test
Reconstruction of the Spanish money supply, 1492–1810
How did the Spanish money supply evolve in the aftermath of the discovery of large amounts of precious metals in Spanish America? We synthesize the available data on the mining of precious metals and their international flow to estimate the money supply for Spain from 1492 to 1810. Our estimate suggests that the Spanish money supply increased more than ten-fold. Viewed through the equation of exchange this money supply increase can account for most of the price level rise in early modern Spain.info:eu-repo/semantics/publishedVersio
Realizing Hopf Insulators in Dipolar Spin Systems
The Hopf insulator represents a topological state of matter that exists
outside the conventional ten-fold way classification of topological insulators.
Its topology is protected by a linking number invariant, which arises from the
unique topology of knots in three dimensions. We predict that three-dimensional
arrays of driven, dipolar-interacting spins are a natural platform to
experimentally realize the Hopf insulator. In particular, we demonstrate that
certain terms within the dipolar interaction elegantly generate the requisite
non-trivial topology, and that Floquet engineering can be used to optimize
dipolar Hopf insulators with large gaps. Moreover, we show that the Hopf
insulator's unconventional topology gives rise to a rich spectrum of edge mode
behaviors, which can be directly probed in experiments. Finally, we present a
detailed blueprint for realizing the Hopf insulator in lattice-trapped
ultracold dipolar molecules; focusing on the example of KRb, we
provide quantitative evidence for near-term experimental feasibility.Comment: 6 + 7 pages, 3 figure
Liouvillian Dynamics of the Open Schwinger Model: String Breaking and Kinetic Dissipation in a Thermal Medium
Understanding the dynamics of bound state formation is one of the fundamental
questions in confining quantum field theories such as Quantum Chromodynamics
(QCD). One hadronization mechanism that has garnered significant attention is
the breaking of a string initially connecting a fermion and an anti-fermion.
Deepening our understanding of real-time string-breaking dynamics with simpler,
lower dimensional models like the Schwinger model can improve our understanding
of the hadronization process in QCD and other confining systems found in
condensed matter and statistical systems. In this paper, we consider the
string-breaking dynamics within the Schwinger model and investigate its
modification inside a thermal medium, treating the Schwinger model as an open
quantum system coupled to a thermal environment. Within the regime of weak
coupling between the system and environment, the real-time evolution of the
system can be described by a Lindblad evolution equation. We analyze the
Liouvillian gaps of this Lindblad equation and the time dependence of the
system's von Neumann entropy. We observe that the late-time relaxation rate
decreases as the environment correlation length increases. Moreover, when the
environment correlation length is infinite, the system exhibits two steady
states, one in each of the sectors with definite charge-conjugation-parity (CP)
quantum numbers. For parameter regimes where an initial string breaks in
vacuum, we observe a delay of the string breaking in the medium, due to kinetic
dissipation effects. Conversely, in regimes where an initial string remains
intact in vacuum time evolution, we observe string breaking (melting) in the
thermal medium. We further discuss how the Liouvillian dynamics of the open
Schwinger model can be simulated on quantum computers and provide an estimate
of the associated Trotter errors.Comment: 23 pages, 16 figure
Quantum simulation of non-equilibrium dynamics and thermalization in the Schwinger model
We present simulations of non-equilibrium dynamics of quantum field theories
on digital quantum computers. As a representative example, we consider the
Schwinger model, a 1+1 dimensional U(1) gauge theory, coupled through a
Yukawa-type interaction to a thermal environment described by a scalar field
theory. We use the Hamiltonian formulation of the Schwinger model discretized
on a spatial lattice. With the thermal scalar fields traced out, the Schwinger
model can be treated as an open quantum system and its real-time dynamics are
governed by a Lindblad equation in the Markovian limit. The interaction with
the environment ultimately drives the system to thermal equilibrium. In the
quantum Brownian motion limit, the Lindblad equation is related to a field
theoretical Caldeira-Leggett equation. By using the Stinespring dilation
theorem with ancillary qubits, we perform studies of both the non-equilibrium
dynamics and the preparation of a thermal state in the Schwinger model using
IBM's simulator and quantum devices. The real-time dynamics of field theories
as open quantum systems and the thermal state preparation studied here are
relevant for a variety of applications in nuclear and particle physics, quantum
information and cosmology.Comment: 18 pages, 8 figure
Characterization of Waste From Attiéké Factory: Case of Azito Village (Abidjan, Côte d’Ivoire)
The control of the anaerobic digestion of cassava residues from attiéké factories requires their characterization to offer a better working environment to attiéké producers. This study concerns at first the quantity of solid residues of cassava, dough of crushed cassava and other waste generated by the process of attiéké production. The second aspect concerns the determination of some physicochemical parameters (COD, TKN, pH, COD/TKN). These two aspects were realized thanks to the use of a bag in synthetic fibers, a dynamometric steelyard with dial of diameter 17 cms, and the use of a gradual can of capacity 20 L. The results of this study showed that an average quantity of 1.53 tonne of manioc handled (treated) generates 1.14 m3 of effluents and 0.16 tonne of solid waste per day. These effluents are acid with a pH ranged between 2.54 and 4.80. So they have on average a DCO of 58.79 g/L for 0,71 g/L of nitrogen. All these parameters help control the optimal conditions of anaerobic digestion of cassava effluents in the manufacturing process of attiéké
Regulating collateral-Requirements when markets are incomplete
In this paper we examine the effects of default and scarcity of collateralizable durable goods on risk-sharing. We assume that there is a large set of assets which all
promise a risk-less payo but which distinguish themselves by the collateral requirement. In equilibrium agents default and the assets have dierent payoffs. Assets with very low collateral requirements can be interpreted as sub-prime loans and these assets are often traded actively in the competitive equilibrium. If there is an abundance of commodities that can be used as collateral and if each agent
owns a large fraction of these commodities, markets are complete and competitive equilibrium allocations Pareto optimal. If, on the other hand, the collateralizable durable good is scarce or if some agents do not own enough of the collateralizable durable good in the first
period, markets can be endogenously incomplete, not all of the available assets are traded in the competitive equilibrium and allocations are not Pareto optimal. We give examples that show that welfare losses can be quantitatively large.
We also examine the scope for government intervention. In particular we ask who in the economy gains and who loses if collateral requirements are regulated exogenously. In our
examples, regulation never leads to a Pareto-improvement. Often, the rich and the poor agents gain if trade is restricted to subprime contracts and lose if trade in these contracts is not allowed
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