Application of replacement theory in dairy cows and its use in disease treatment

A model to simulate the costs and returns of an individual dairy cow over 14 years under various assumptions of genetic potential, health status and management was developed especially to evaluate the effects of diseases that reduce production and reproduction efficiency and to evaluate alternative management interventions. Data were collected from the Food Animal Health Resource Management System (FAHRMX), Today's Electronic Planning (TELPLAN), Today's Electric Farm Accounting (TELFARM) databases and secondary sources at Michigan State University. A case study of cystic ovaries was analysed using the model. The results showed that it is more economical to treat cystic ovaries than not to treat, and treatment with Gonadotropin Releasing Hormone (GNRH) was superior to Human Chrionic Gonadotropin (HCG). Four to five lactations were the optimum for keeping a dairy cow to replacement and it was estimated that there is a loss of US$0.45 per day of extended calving interval (days open beyond the optimal 70 days).     

The welfare effects of disclosure under cognitive dissonance

Atlantic Economic Journal -     

Asymptotically optimal estimation of smooth functionals for interval censoring, part 1

Estimation in the interval censoring model is considered. A class of smooth functionals is introduced, of which the mean is an example. The asymptotic information lower bound for such functionals can be represented as an inner product of two functions. In case 1, i.e. one observation time per unobservable event time, both functions can be given explicitly. We mainly consider case 2, with two observation times for each unobservable event time, in the situation that the observation times can not become arbitrarily close to each other. For case 2, one of the functions in the inner product can only be given implicitly as solution to a Fredholm integral equation. We study properties of this solution and, in a sequel to this paper, prove that the nonparametric maximum likelihood estimator of the functional asymptotically reaches the information lower bound.     

The Lowry Model Revisited: Incorporating a Multizonal Input-Output Model into an Urban Land Use Allocation Model

This paper formulates a new generation of Lowry-style models that combine a multizonal input-output model and an urban land use allocation model. Three different types of models are proposed: 1) an unconstrained model, 2) a primal of a linear programming approach that includes land supply constraints, and 3) a modified dual of the linear programming approach that allocates land based on additional conditions of economic efficiency. The modified dual formulation improves upon the limitations of Lowry models and their derivatives. First, the proposed model has sound theoretical underpinnings that incorporate the production theory of input-output models and the behavioral theory of optimization models. Second, the proposed model allocates land on the basis of economic efficiency by imposing a procedure that equalizes shadow prices. And third, the proposed model is an optimization model that fully accounts for the spatial and sectoral relationships of multiplier effects determining land use demand.     

Wavelet Analysis of the Bombay Stock Exchange Index

The fluctuations in the rate of returns of the Bombay stock exchange are analyzed through wavelet transform. The fluctuations, in various time scales, naturally separated by the wavelets, are subjected to statistical analysis. The localization and multiresolution properties of the wavelets enable one to identify collective behaviour in the stock market and the extent of their influence at various time scales. The Gaussian nature of the rate of returns at certain scales and the periodic nature of the same, at other scales, are clearly brought out by this analysis. The utility of this approach for modeling purpose is also elucidated.

     

Likelihood-based specification analysis of continuous-time models of the short-term interest rate

An extensive collection of continuous-time models of the short-term interest rate is evaluated over data sets that have appeared previously in the literature. The analysis, which uses the simulated maximum likelihood procedure proposed by Durham and Gallant (2002), provides new insights regarding several previously unresolved questions. For single factor models, I find that the volatility, not the drift, is the critical component in model specification. Allowing for additional flexibility beyond a constant term in the drift provides negligible benefit. While constant drift would appear to imply that the short rate is nonstationary, in fact, stationarity is volatility-induced. The simple constant elasticity of volatility model fits weekly observations of the three-month Treasury bill rate remarkably well but is easily rejected when compared with more flexible volatility specifications over daily data. The methodology of Durham and Gallant can also be used to estimate stochastic volatility models. While adding the latent volatility component provides a large improvement in the likelihood for the physical process, it does little to improve bond-pricing performance.     

Myopic loss aversion and the equity premium puzzle reconsidered

Benartzi and Thaler [The Quarterly Journal of Economics 110 (1995) 73–92] offer a quasi-rational explanation for the equity premium puzzle. We reconsider their methodology and, making a simple modification to it, find that their analysis is not robust.     

Universal service through roll‐out targets and licence conditions: lessons from telecommunications in South Africa

A priority for the post‐apartheid government was the extension of basic infrastructure services to the vast majority of citizens that were not serviced under apartheid. The Reconstruction and Development Programme set objectives for each of these utilities that would be achieved in the first decade of democracy, while departmental policy aimed to find means of achieving these targets. The strategy of choice in most sectors was one of ambitious roll‐out targets being set for utility operators. Targets were set for individual residential service (‘universal service’) and for community service outside of individual homes (‘universal access’). While most utilities remained under public ownership, in telecommunications there was partial privatisation of the incumbent Telkom and the entry of privately owned mobile cellular operators. This article examines how roll‐out targets and licence conditions for universal service have performed in this sector where private operators exist. It examines the failure of the Telkom licence and draws out some lessons for policy.