Modelling the impacts of the industrial biofuels strategy on the South African agricultural and biofuel subsectors

The potential impact of the current South African industrial biofuels strategy on the economic feasibility of biofuel production in South Africa is analysed and discussed. The analysis is then taken a step further by means of a scenario to analyse the potential impacts of higher global prices on the feasibility of a local biofuel industry. The BFAP sector model, a partial equilibrium model, is used to simulate the various impacts over the period 2009 to 2017. This study shows that the incentives and commitments, as presented through the strategy, are not sufficient to get a local biofuel industry up and running and make it sustainable in the long term.Resource /Energy Economics and Policy,

Modelling the impacts of macro-economic variables on the South African biofuels industry

The production of biofuels from agricultural commodities has received much attention in recent years. Apart from a few private initiatives, biofuels have not seen a large scale, commercial production in South Africa to date. This article sketches a basic picture of the economic feasibility of biofuel production in South Africa, without any form of government support, at 2006 prices. It then takes the analysis a step further and with the aid of a set of scenarios, different potential outcomes, due to a range of possible policy implementation measures, are discussed and the results documented. The Bureau for Food and Agricultural Policy’s (BFAP) sector model is used to simulate the impact of various options on the potential biofuels industry and other related industries during the course of the 2007 to 2015 period. This study shows that a lack of government support for the local biofuels industry could seriously affect its economic viability, especially in the early stages of the industry’s development. Additional issues, such as the impact on food and feed prices, also need to be taken into consideration.Resource /Energy Economics and Policy,

Coupling of non-crossing wave modes in a two-dimensional plasma crystal

We report an experimental observation of coupling of the transverse vertical and longitudinal in-plane dust-lattice wave modes in a two-dimensional complex plasma crystal in the absence of mode crossing. A new large diameter rf plasma chamber was used to suspend the plasma crystal. The observations are confirmed with molecular-dynamics simulations. The coupling manifests itself in traces of the transverse vertical mode appearing in the measured longitudinal spectra and vice versa. We calculate the expected ratio of the trace to the principal mode with a theoretical analysis of the modes in a crystal with finite temperature and find good agreement with the experiment and simulations.Comment: 4 figures, 5 pages, accepted for publication in PRL Nov 201

Position Errors Caused by GPS Height of Instrument Blunders

Height of instrument (HI) blunders in GPS measurements cause position errors. These errors can be pure vertical, pure horizontal, or a mixture of both. There are different error regimes depending on whether both the base and the rover both have HI blunders, if just the base has an HI blunder, or just the rover has an HI blunder. The resulting errors are on the order of 30 cm for receiver separations of 1000 km for an HI blunder of 2 m. Given the complicated nature of the errors, we believe it would be difficult, if not impossible, to detect such errors by visual inspection. This serves to underline the necessity to enter GPS HI\u27s correctly

On the "generalized Generalized Langevin Equation"

In molecular dynamics simulations and single molecule experiments, observables are usually measured along dynamic trajectories and then averaged over an ensemble ("bundle") of trajectories. Under stationary conditions, the time-evolution of such averages is described by the generalized Langevin equation. In contrast, if the dynamics is not stationary, it is not a priori clear which form the equation of motion for an averaged observable has. We employ the formalism of time-dependent projection operator techniques to derive the equation of motion for a non-equilibrium trajectory-averaged observable as well as for its non-stationary auto-correlation function. The equation is similar in structure to the generalized Langevin equation, but exhibits a time-dependent memory kernel as well as a fluctuating force that implicitly depends on the initial conditions of the process. We also derive a relation between this memory kernel and the autocorrelation function of the fluctuating force that has a structure similar to a fluctuation-dissipation relation. In addition, we show how the choice of the projection operator allows to relate the Taylor expansion of the memory kernel to data that is accessible in MD simulations and experiments, thus allowing to construct the equation of motion. As a numerical example, the procedure is applied to Brownian motion initialized in non-equilibrium conditions, and is shown to be consistent with direct measurements from simulations

Measuring Integration and Efficiency in Maize Grain Markets: The Case of South Africa and Mozambique

Price transmission between the South African market and other regional markets is not as straightforward, despite South Africa’s role of a surplus producer for the region. There appears to be a host of local factors that must be taken into account in order to anticipate the likely level of regional food prices. This article assesses the degree of market integration and the speed of price adjustment to spatial price differentials between the SAFEX maize price in South Africa and maize grain and maize meal prices in Maputo, Mozambique. The findings of this study indicate that under certain trading regimes, there is no evidence of a long-run relationship between Mozambican and South African maize grain prices. This implies that any large deviations, within these regimes, which exceed transaction costs, could continue to grow with no tendency towards equilibrium. However, the trade volume data indicates maize grain exports from South Africa into Mozambique in every month except for three within the sample set. Hence, the empirical findings of this paper are unexpected given a simple arbitrage argument. Possible reasons for these findings are highlighted in the article. It is interesting to note that when the same empirical analysis is undertaken for the SAFEX maize prices and maize meal prices in Maputo then there is in fact evidence of a long-run relationship between these prices in a high import regime. These findings are not surprising and are what we would expect since two of the largest milling companies, located in Maputo are responsible for the majority of the volume of maize grain imported into the country from South Africa.price transmission, market integration, cointegration, trade regimes, Crop Production/Industries,

Lorentz meets Fano spectral line shapes: A universal phase and its laser control

Symmetric Lorentzian and asymmetric Fano line shapes are fundamental spectroscopic signatures that quantify the structural and dynamical properties of nuclei, atoms, molecules, and solids. This study introduces a universal temporal-phase formalism, mapping the Fano asymmetry parameter q to a phase {\phi} of the time-dependent dipole-response function. The formalism is confirmed experimentally by laser-transforming Fano absorption lines of autoionizing helium into Lorentzian lines after attosecond-pulsed excitation. We also prove the inverse, the transformation of a naturally Lorentzian line into a Fano profile. A further application of this formalism amplifies resonantly interacting extreme-ultraviolet light by quantum-phase control. The quantum phase of excited states and its response to interactions can thus be extracted from line-shape analysis, with scientific applications in many branches of spectroscopy.Comment: 11 pages, 4 figure

Forecasting rain events in the southern Great Plains using GPS total precipitable water amounts

Includes bibliographical references.Funding for this research is supported by an American Meteorological Society Graduate Student Fellowship, sponsored by the National Oceanic and Atmospheric Administration's (NOAA) Office of Global Programs, by NOAA under cooperative agreement NA17RJ1228 with CIRA, and by the Research and Scholarly Programs fund at Colorado State University (CSU)

Characterizing Scales of Genetic Recombination and Antibiotic Resistance in Pathogenic Bacteria Using Topological Data Analysis

Pathogenic bacteria present a large disease burden on human health. Control of these pathogens is hampered by rampant lateral gene transfer, whereby pathogenic strains may acquire genes conferring resistance to common antibiotics. Here we introduce tools from topological data analysis to characterize the frequency and scale of lateral gene transfer in bacteria, focusing on a set of pathogens of significant public health relevance. As a case study, we examine the spread of antibiotic resistance in Staphylococcus aureus. Finally, we consider the possible role of the human microbiome as a reservoir for antibiotic resistance genes.Comment: 12 pages, 6 figures. To appear in AMT 2014 Special Session on Advanced Methods of Interactive Data Mining for Personalized Medicin