Bayesian Analysis of Continuous Time Models of the Australian Short Rate

This paper provides an empirical analysis of a range of alternative single-factor continuous time models for the Australian short-term interest rate. The models are indexed by the level effect parameter for the volatility in the short rate process. The inferential approach adopted is Bayesian, with estimation of the models proceeding via a Markov Chain Monte Carlo simulation scheme. Discrimination between the alternative models is based on Bayes factors, estimated from the simulation output using the Savage-Dickey density ratio. A data augmentation approach is used to improve the accuracy of the discrete time approximation of the continuous time models. An empirical investigation is conducted using weekly observations on the Australian 90 day interest rate from January 1990 to July 2000. The Bayes factors indicate that the square root diffusion model has the highest posterior probability of all the nested models.Interest Rate Models, Markov Chain Monte Carlo, Data Augmentation

One Share/One Vote and the Market for Corporate Control

A corporation's securities provide the holder with particular claims on the firm's income stream and particular voting rights. These securities can be designed in various ways: one share of a particular class may have a claim to votes which is disproportionately larger or smaller than its claim to income. In this paper we analyze some of the forces which make it desirable to set up the corporation so that all securities have the same proportion of votes as their claim to income ("one share/one vote"). We show that security structure influences both the conditions under which a control change takes place and the terms on which it occurs. First, the allocation of voting rights to securities determines which securities a party must acquire in order to win control. Secondly, the assignment of income claims to the same securities determines the cost of acquiring these voting rights. We will show that it is in shareholders' interest to set the cost of acquiring control to be as large as possible, consistent with a control change occurring whenever this increases shareholder wealth. Under certain assumptions, one share/one vote best achieves this goal. We distinguish between two classes of benefits from control: private benefits and security benefits. The private benefits of control refer to benefits the current management or the acquirer obtain for themselves, but which the target security holders do not obtain. The security benefits refer to the total market value of the corporation's securities. The assignment of income claims to voting rights determines the extent 'to which an acquirer must face competition from parties who value the firm for its security benefits rather than its private benefits.

Simulation-Based Bayesian Estimation of Affine Term Structure Models

This paper demonstrates the application of Bayesian simulation-based estimation to a class of interest rate models known as Affine Term Structure (ATS) models. The technique used is based on a Markov Chain Monte Carlo algorithm, with the discrete observations on yields augmented by additional higher frequency latent data. The introduction of augmented yield data reduces the bias associated with estimating a continuous time model using discretely observed data. The technique is demon-strated using a one-factor ATS model, with the latent factor process that underlies the yields sampled via a single-move algorithm. Numerical application of the method is demonstrated using both simulated and empirical data. Extension of the method to a three-factor ATS model is also discussed, as well as the application of a multi-move sampler based on a Kalman Filtering and Smoothing algorithm.Interest Rate Models, Markov Chain Monte Carlo, Data Augmentation, Nonlinear State Space Models, Kalman Filtering.

Skylab food system

A review of the Skylab food system requirements, package designs, and launch configurations was presented. In-flight anomalies were discussed, and between-mission changes in design were described. A discussion of support for Skylab 3 and Skylab 4 mission extensions and of new items launched on these missions is included

Metopolophium festucae cerealium (Hemiptera: Aphididae) : a new addition to the aphid fauna of North America

Metopolophium festucae cerealium (Stroyan) (Hemiptera: Aphididae) was found in wheat fields in the Pacific Northwest in 2011 and 2012. This is the first record of M. f. cerealium in North America. This subspecies can be a serious pest of cereal crops

Masoncus Spider: A Miniature Predator of Collembola in Harvester Ant Colonies

Volume: 92Start Page: 145End Page: 15

Unemployment with Observable Aggregate Shocks

Consider an economy subject to two kinds of shocks: (a) an observable shock to the relative demand for final goods which causes dispersion in relative prices, and (b) shocks, unobservable by workers, to the technology for transforming intermediate goods into final goods. A worker in a particular intermediate goods industry knows that the unobserved price of his output is determined by (1) the technological shock that determines which final goods industry uses his output intensively and (2) the price of the final good that uses his output intensively. When there is very little relative price dispersion among final goods, then it doesn't matter which final goods industry uses the worker's output. Thus the technological shock is of very little importance in creating uncertainty about the worker's marginal product when there is little dispersion of relative prices. Hence an increase in the dispersion of relative prices amplifies the effect of technological uncertainty on a worker's marginal value product. We consider a model of optimal labor contracts in a situation where the workers have less information than the firm about their marginal value product. A relative price shock of the type described above increases the uncertainty which workers have about their marginal value product. We show that with an optimal asymmetric information employment contract the industries which are adversely affected by the relative price shock will contract more than they would under complete information (i.e., where workers could observe their marginal value product). On the other hand the industry which is favorably affected by the relative price shock will - not expand by more than would be the case under complete information. Hence an observed relative demand shock, which would leave aggregate employment unchanged under complete information, will cause aggregate employment to fall under asymmetric information about the technological shock.