A quantitative analysis of Zimbabwe's land reform policy: An application of Zimbabwe SAM multipliers

This study was designed to quantitatively investigate the economy-wide impact of land reform policies in Zimbabwe. Land reforms came with the realm of independence in Zimbabwe. Four models were used to implement the reform policies. The paper uses the updated 1991 Social Accounting Matrix for Zimbabwe and the Central Statistics Office's household data on resettled families in Zimbabwe. The paper computes the sectoral SAM multipliers and then uses household data on resettled families to simulate the impact of specific land reform models on the economy. The simulated results show that land reform, if well planned and systematically and carefully implemented, could generate economy-wide benefits for Zimbabwe and could lead to income redistribution in favour of low-income household groups, while maintaining an increase in households' aggregate income.Land Economics/Use,

Transition Temperature of a Magnetic Semiconductor with Angular Momentum j

We employ dynamical mean-field theory to identify the materials properties that optimize Tc for a generalized double-exchange (DE) model. We reach the surprising conclusion that Tc achieves a maximum when the band angular momentum j equals 3/2 and when the masses in the 1/2 and 3/2 sub-bands are equal. However, we also find that Tc is significantly reduced as the ratio of the masses decreases from one. Consequently, the search for dilute magnetic semiconductors (DMS) materials with high Tc should proceed on two fronts. In semiconductors with p bands, such as the currently studied Mn-doped Ge and GaAs semiconductors, Tc may be optimized by tuning the band masses through strain engineering or artificial nanostructures. On the other hand, semiconductors with s or d bands with nearly equal effective masses might prove to have higher Tc's than p-band materials with disparate effective masses.Comment: 5 pages, 4 figure

ESR Study of Optically Induced Phase Transitions

We have identified an optically enhanced magnetic phase transition in the newly synthesized organic molecular charge transfer salt, (BEDT-TTF)3Ta2F11 (BEDT-TTF bisethylenedithiolotetrathiafulvalene) by ESR absorption measurements in the X band microwave region. At room temperature, only a doublet state ESR absorption is observed, but below 30 K severa~ tripl~t E.SR absorpti_ons appear. The orientation dependence of the ESR absorption under lllummat10n at energies near the band gaps in the material ( 640 nm, T = 12 to 5 K H0 \u3c 0.34 T) indicates that there are rapid spin exchange processes with times r \u3c w-s; near 7 ~o 5 K.along cert~in ~rystallographic directions with a temperature dependen~e suggesting spm-lattlce relaxation times which proceed via Van Vleck direct processes. This, to our knowledge, is the first case where the magnetic properties of a charge transfer salt are altered by the interaction with photons of energy equal to the band gaps in a low dimensional solid providing a new, interesting way to investigate these materials

Inter-sectoral Water Use in South Africa: Efficiency Versus Equity

While water supply sources are dwindling in South Africa, the demand for the scarce water resource is increasing. This situation requires a switch from supply to demand management of water in the country. The study updates the 1999 social accounting matrix for South Africa, using the Trade and Industrial Policy Strategies (TIPS) time series data, STATSA's 2001 census report and 2000 water accounts, the 2002 national income accounts, published by the South African Reserve Bank (SARB) and the Water Resource Management Strategy (WRMS) registration data. Using the updated SAM, the contribution of water to economic development in South Africa is estimated through the traditional SAM multiplier analysis. The paper then investigates the impact of reallocating water among the production sectors, on the basis of economic efficiency, on output growth, factor remuneration and households' income generation. The computational and simulation results show that, though agriculture is among the sectors that have the least marginal value of water, water reallocation based on marginal values will reduce the incomes of the poorest households, and put at stake the livelihoods of the most vulnerable population. Scenario analyses suggest that this effect will be minimal if marginal productivity consideration for inter-sectoral water reallocation is reduced to 30%, while intra-sectoral water reallocation on the basis of efficiency is currently viewed as the most viable option.SAM multipliers, output growth, factor remuneration, income generation, efficiency, equity, R20, Resource /Energy Economics and Policy, C67, D57, L60, Q25,

Households’ welfare analyses of the impact of global change on water resources in South Africa

Most of the climate change models for South Africa predict a reduction in freshwater availability by 2050. Population growth is projected at 3% per annum, implying increased domestic water use. In addition to these factors, the concern for ecological sustainability and increased water pollution due to increased industrial, mining and agricultural activities, water availability for sectoral production activities is expected to decline. This decline has an impact on sectoral output, value added and households’ welfare. Using a computable general equilibrium approach, this study investigates the possible impact of global change on households’ welfare. The simulation results show that water scarcity due to global change can potentially lead to a general deterioration in households’ welfare. The poor households, whose incomes are adversely impacted, are the most vulnerable to the consequences of the impact of global change on water resources in South Africa. This vulnerability can only be reduced if welfare policies that maintain food consumption levels for the least and low-income households are implemented.Resource /Energy Economics and Policy,

Recurrence of Ganglion Cysts Following Re-excision

Previous studies have examined the recurrence of ganglion cysts after surgical excision at a rate of 4 to 40%. However, recurrence after revision surgical excision is unknown. The purpose of this study was to define the incidence of recurrent ganglion cysts in patients who underwent a 2nd excisional procedure.https://jdc.jefferson.edu/cwicposters/1032/thumbnail.jp

A multi-orbital iterated perturbation theory for model Hamiltonians and real material-specific calculations of correlated systems

Perturbative schemes utilizing a spectral moment expansion are well known and extensively used for investigating the physics of model Hamiltonians and real material systems. The advantages they offer, in terms of being computationally inexpensive, with real frequency output at zero and finite temperatures, compensate for their deficiencies and offer a quick, qualitative analysis of the system behavior. In this work, we have developed a method, that can be classified as a multi-orbital iterative perturbation theory (MO-IPT) to study N-fold degenerate and non degenerate Anderson impurity models. As applications of the solver, we have combined the method with dynamical mean field theory to explore lattice models like the single orbital Hubbard model, covalent band insulator and the multi-orbital Hubbard model for density-density type interactions in different parameter regimes. The Hund's coupling effects in case of multiple orbitals is also studied. The limitations and quality of results are gauged through extensive comparison with data from the numerically exact continuous time quantum Monte Carlo method (hybridization expansion CTQMC). In general we observe that the agreement with CTQMC results gets better as we move away from particle-hole symmetry. We have integrated MO-IPT with density functional theory based electronic structure methods to study real material systems. As a test case, we have studied the classic, strongly correlated electronic material, SrVO$_3$. A comparison of density of states and photo emission spectrum (PES) with results obtained from different impurity solvers and experiments yields good agreement.Comment: 20 pages, 20 figure

Thermodynamic Consistency of the Dynamical Mean-Field Theory of the Double-Exchange Model

Although diagrammatic perturbation theory fails for the dynamical-mean field theory of the double-exchange model, the theory is nevertheless Phi-derivable and hence thermodynamically consistent, meaning that the same thermodynamic properties are obtained from either the partition function or the Green's function. We verify this consistency by evaluating the magnetic susceptibility and Curie temperature for any Hund's coupling.Comment: 9 pages, 1 figur

A first principles investigation of cubic BaRuO3_3: A Hund's metal

A first-principles investigation of cubic-BaRuO$_3$, by combining density functional theory with dynamical mean-field theory and a hybridization expansion continuous time quantum Monte-Carlo solver, has been carried out. Non-magnetic calculations with appropriately chosen on-site Coulomb repulsion, $U$ and Hund's exchange, $J$, for single-particle dynamics and static susceptibility show that cubic-BaRuO$_3$ is in a spin-frozen state at temperatures above the ferromagnetic transition point. A strong red shift with increasing $J$ of the peak in the real frequency dynamical susceptibility indicates a dramatic suppression of the Fermi liquid coherence scale as compared to the bare parameters in cubic-BaRuO$_3$. The self-energy also shows clear deviation from Fermi liquid behaviour that manifests in the single-particle spectrum. Such a clean separation of energy scales in this system provides scope for an incoherent spin-frozen (SF) phase, that extends over a wide temperature range, to manifest in non-Fermi liquid behaviour and to be the precursor for the magnetically ordered ground state.Comment: 10 pages, 12 figures, 1 tabl