ECONOMETRIC METHODOLOGY II : STRENGTHENING TIME SERIES ANALYSIS

This article reviews some of the recent methodology developed for the analysis of time series data stressing that the statistical properties of the individual series need to be analysed to avoid spurious regressions. A convergence of econometric methodology is entertained with specific focus on cointegration and error correction models which allows the testing of long run relationships between variables and allows for a more dynamic structure than some of the previous models that appear in the literature. An example of this is the commonly used partial adjustment model in supply analysis which is nested in the less restrictive error correction model. Tests can be performed on the validity of these restrictions. These models have a wide application in agricultural economic analysis.Research Methods/ Statistical Methods,

Production Incentives for Small Scale Farmers in Zimbabwe: The Case of Cotton and Maize

The paper presents an empirical investigation of the production response of small scale producers of maize and cotton for communal agriculture in Zimbabwe. The error correction model, which employs the concept of cointegration to avoid spurious regressions, is used in the analysis. The factors affecting maize output were the price of maize relative to seed, the number of marketing depots established in the communal areas and the number of loans provided to these farmers. The factors affecting cotton output were the increase in communal lands due to the resettlement program, the number of loans extended to small scale farmers and the price of cotton relative to seed. The weather played the most significant role in determining the quantity of maize sold.Agricultural and Food Policy, Crop Production/Industries,

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,

Demand for livestock tick control service in the Venda region, Northern Province

This article analyses factors influencing farmers’ willingness-to-pay for dipping services, as well as the revealed preference for dipping frequency using the multivariate and the logistic regression models. The study is based on a cross sectional survey of 125 smallscale cattle farmers interviewed in the Venda region of the Northern Province. Empirical multivariate and the logistic regression analysis show that liquidity, human resource, satisfaction with the programme and structure of production significantly influences farmers’ willingness-to-pay. However, the most important factor influencing both the willingness-to-pay and the dipping frequency is liquidity (employment). The results of this study have important implications for the delivery of veterinary services particularly in developing regions.Livestock Production/Industries,

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,

HERD SIZE AND EFFICIENCY ON MIXED CROP AND LIVESTOCK FARMS: CASE STUDIES OF CHIWESHE AND GOKWE, ZIMBABWE

This study is based on two 1991 sample surveys, each of ninety farms, in the predominantly arable region of Chiweshe and in the low rainfall area of Gokwe, where animals are more important. The two samples are reasonably representative of the range of conditions found in the communal areas in Zimbabwe. Programming techniques are used to determine the efficiency levels of the farms in each region. The results show that efficiency is positively related to the numbers of both cows and oxen, with only a few farms in Gokwe possibly having too many animals. Farms in Gokwe are on average about two thirds as efficient as those in Chiweshe, which is a measure of the effects of the poorer climate and soils. Non-farm income is also lower, due to lesser opportunities in the more remote region. In both regions, the majority of farms are too small and the estimates suggest that increasing farm size could almost double productivity.Farm Management, Livestock Production/Industries,

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,

Sex differences in short-term mate preferences and behavioral mimicry: A semi-naturalistic experiment

Item does not contain fulltextStudies on short-term mating (STM) yield sex differences regarding preferences for attractiveness (important towomen, very important to men) and social status (very important to women, not to men) in potential mates. Additionally, men generally report a greater desire to engage in STM than women. So far, this evidence is primarily based on studies using vignettes or surveys. The current study extended the findings on sex differences in STM by examining actual behavior and STM-desires towards real people of the opposite sex. It investigated whether (1) sex differences exist in STM-desire, (2) whether this desire was affected by a confederate's attractiveness and status, and (3) if these sex differences were also reflected in interpersonal behavior (mimicry). In a pub-like laboratory, single heterosexual participants performed a task alongside a confederate of the opposite sex, who differed in attractiveness and social status. Mimicry was observed and explicit STM-desire was assessed. Results showed that men only desired STM more than women in the case of an attractive partner. Women's STMdesire did not vary as a function of status or ttractiveness of the potential partner. Men’s, but not women's, mimicry paralleled these differential STM-desires. These results underline the conditionality of sex differences in STM-desire and provide a useful paradigm to further investigate STM.10 p

Quantum Communication

Quantum communication, and indeed quantum information in general, has changed the way we think about quantum physics. In 1984 and 1991, the first protocol for quantum cryptography and the first application of quantum non-locality, respectively, attracted a diverse field of researchers in theoretical and experimental physics, mathematics and computer science. Since then we have seen a fundamental shift in how we understand information when it is encoded in quantum systems. We review the current state of research and future directions in this new field of science with special emphasis on quantum key distribution and quantum networks.Comment: Submitted version, 8 pg (2 cols) 5 fig