Estimation of the rate of return to wine grape research and technology development expenditures in South Africa

This article evaluates the impact of research and technology development in the wine grape industry in order to determine the rate of return (ROR) to these investments, and to make specific recommendations on funding. The analysis illustrates the applied and adaptive nature of the research conducted in the industry, with RORs of roughly 40 percent for R&D and extension. This is high, providing excellent motivation for increased investment in R&D.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

Testing the induced innovation hypothesis in South African agriculture (an error correction approach)

The authors investigate whether factor prices matter in agricultural production and in the selection of production technology. Each stage of the analysis corroborates the inducement hypothesis, which implies that factor prices do matter in agricultural production and in the selection of production technology. The empirical results also suggest that observed rates and biases of technological change are influenced by average farm size, by spending on research and extension, and by favorable tax and interest-rate policies. In South Africa, the authors contend, more attention should be focused on the technological needs of small-scale farmers. The lobbying power of the large commercial farmers, combined with policies followed under apartheid, must have influenced the allocation of research and development funds between labor- and land-saving technical change. This will have distorted the technological bias toward labor saving technical change, which is hardly appropriate for a labor-surplus economy in which small farmers in the former homelands face a chronic scarcity of land. These results show that factor prices do matter in agricultural production and the selection of production technology. And there seems to be merit to the World Bank's usual policy prescription - structural adjustment and market liberalization - for economies in which prices are controlled and distorted. They investigate the role of factor prices by applying cointegration techniques to a model of induced innovation based on the two-stage constant elasticity of substitution production function. This approach results in direct tests of the inducement hypothesis, which are applied to data for South African agriculture for the period 1947-92. They check the time series properties of the variables, establish cointegration, and construct an error correction model (ECM) that allows factor substitution to be separated from technological change. Finally, they subject the ECM formulation to tests of causality, which show that the factor price ratios induce the factor saving biases of technological change.Economic Theory&Research,Environmental Economics&Policies,Agricultural Knowledge&Information Systems,Scientific Research&Science Parks,Markets and Market Access,Environmental Economics&Policies,Economic Theory&Research,Agricultural Knowledge&Information Systems,Scientific Research&Science Parks,Science Education

Domain Walls on the Brane

We show that all branes admit worldvolume domain wall solutions. We find one class of solutions for which the tension of the brane changes discontinuously along the domain wall. These solutions are not supersymmetric. We argue that there is another class of domain wall solutions which is supersymmetric. A particular case concerns supersymmetric domain wall solutions on IIB D-5- and NS-5-branes.Comment: 18 pages, Tex, uses phyzz

Assessing the benefits of research expenditures on maize production in South Africa

This paper focuses on assessing the benefits of research expenditures on maize production in South Africa. Both the production and supply function approaches are used to calculate elasticities of research expenditure on output and yield. Cointegration is used to establish long-run relationships between variables in these models. The lag structure of R&D expenditures on output is examined making use of the unrestricted, polynomial, beta and gamma distributions. The coefficients of these lag distributions were then used to calculate a rate of return to maize research expenditure, which was estimated as being between 28% and 39% per annum. These rates of return are high, mitigating in favour of more research expenditure rather than less.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

Machinery and labour biases of technical change in South African agriculture: A cost function approach

This paper provides an empirical investigation into the long-standing notion of biases of technical change in South African agriculture. The second order cost function is used to derive relative bias measures between labour and machinery. The results suggest that large machinery-using biases in technology have been developed with minimal labour-using biases.Farm Management, Research and Development/Tech Change/Emerging Technologies,

Discovery of a strong magnetic field in the rapidly rotating B2Vn star HR 7355

We report the detection of a strong, organized magnetic field in the helium-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on the 3.6-m Canada-France-Hawaii Telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Program. HR 7355 is both the most rapidly rotating known main-sequence magnetic star and the most rapidly rotating helium-strong star, with $v \sin i$ = 300 $\pm$ 15 km s$^{-1}$ and a rotational period of 0.5214404 $\pm$ 0.0000006 days. We have modeled our eight longitudinal magnetic field measurements assuming an oblique dipole magnetic field. Constraining the inclination of the rotation axis to be between $38^{\circ}$ and $86^{\circ}$, we find the magnetic obliquity angle to be between $30^{\circ}$ and $85^{\circ}$, and the polar strength of the magnetic field at the stellar surface to be between 13-17 kG. The photometric light curve constructed from HIPPARCOS archival data and new CTIO measurements shows two minima separated by 0.5 in rotational phase and occurring 0.25 cycles before/after the magnetic extrema. This photometric behavior coupled with previously-reported variable emission of the H$\alpha$ line (which we confirm) strongly supports the proposal that HR 7355 harbors a structured magnetosphere similar to that in the prototypical helium-strong star, $\sigma$ Ori E.Comment: 6 pages, 3 figures. Accepted for publication in MNRAS Letter

Conformal Theory of M2, D3, M5 and `D1+D5' Branes

The bosonic actions for M2, D3 and M5 branes in their own d-dimensional near-horizon background are given in a manifestly SO(p+1,2) x SO(d-p-1) invariant form (p=2,3,5). These symmetries result from a breakdown of ISO(d,2) (with d=10 for D3 and d=11 for M2 and M5) symmetry by the Wess-Zumino term and constraints. The new brane actions, reduce after gauge-fixing and solving constraints to (p+1) dimensional interacting field theories with a non-linearly realized SO(p+1,2) conformal invariance. We also present an interacting two-dimensional conformal field theory on a D-string in the near-horizon geometry of a D1+D5 configuration.Comment: 32 pages, two figures, Latex. A version to appear in JHEP. A comment is added on infinite dimensional Kac-Moody type symmetry of D1+D5 system observed by Brandt, Gomis, Sim'o

Efficient processing of an antigenic sequence for presentation by MHC class I molecules depends on its neighboring residues in the protein

Processing of endogenously synthesized proteins generates short peptides that are presented by MHC class I molecules to CD8 T lymphocytes. Here it is documented that not only the sequence of the presented peptide but also the residues by which it is flanked in the protein determine the efficiency of processing and presentation. This became evident when a viral sequence of proven antigenicity was inserted at different positions into an unrelated carrier protein. Not different peptides, but different amounts of the antigenic insert itself were retrieved by isolation of naturally processed peptides from cells expressing the different chimeric proteins. Low yield of antigenic peptide from an unfavorable integration site could be overcome by flanking the insert with oligo-alanine to space it from disruptive neighboring sequences. Notably, the degree of protection against lethal virus disease related directly to the amount of naturally processed antigenic peptide

Stability of Antisymmetric Tensor Fields of Chern-Simons Type in AdS Spacetime

Stability of massive antisymmetric tensor fields with the Chern-Simons type action in anti de Sitter spacetime is studied. It is found that there exists a complete set of solutions whose energy is conserved and positive definite if the mass is positive. Scalar products of the solutions are shown to be well-defined and conserved. In contrast to the previously studied scalar field case there is no other set of stable solutions with a different kind of boundary condition.Comment: 20 pages, LaTeX, minor changes, references adde

THE RATE OF RETURN ON EXPENDITURES OF THE SOUTH AFRICAN AGRICULTURAL RESEARCH COUNCIL (ARC)

All the rate of return estimates, regardless of methodology or the level of aggregation, are entirely consistent and logical. The returns show that the ARC has been extremely successful economically and has followed a sound strategy of exploiting spillovers from foreign R&D systems. However, there must be a strong socio-economic component to the ARC's efforts if it is to reach the disadvantaged.Research and Development/Tech Change/Emerging Technologies,