COMPARISON OF MICHIGAN FARMLAND RETURNS TO NONFARM INVESTMENTS

Farmland is both a financial investment and a production resource when it is used by the farm family in generating income for the business. The resource is used in producing crops for sale or feed for animals. The basic choices for controlling land are ownership and lease. Land leases allows the control of land for income generation, but it does not allow the lessor to participation in the investment characteristics of the property. Land ownership provides a means for gaining income for the business as well as capital gains for the owner's wealth accumulation. Agricultural land prices increased for almost 50 years until the agricultural financial crisis in the 1980's halted the upward movement in values. From 1981 to 1987, Michigan farmland prices decreased 37 percent. How does the return to farmland compare to the yield from nonfarm investments in the last 10 years? Is agricultural land a good investment? The purpose of this article is an evaluation of investment returns from Michigan farmland for the owners, and a comparison of the returns over time with competing long-term nonfarm investments.Land Economics/Use,

BUSINESS ANALYSIS SUMMARY FOR FRUIT FARMS, 1996 TELFARM

Crop Production/Industries,

MICHIGAN FARM DATABASE NEW DIRECTIONS FOR 1995

The purpose of this paper is to provide financial and production performance data for Michigan farms in 1995. Separate sections report on the farm types of Cash Grain, Dairy, Fruit, General Crop, General Livestock, and Swine. This data can be used as a comparative data base for individual farmers to conduct a financial analysis of their own farm to identify strengths and weaknesses. This report can also provide information to those interested in the financial well being of Michigan agriculture. Immediately following are sections on the data source, and how farm types were defined. The last section of the publication has definitions of calculations. Reader response is requested.Farm Management,

Database system architecture supporting coexisting query languages and data models

SIGLELD:D48239/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Self-induced decoherence approach: Strong limitations on its validity in a simple spin bath model and on its general physical relevance

The "self-induced decoherence" (SID) approach suggests that (1) the expectation value of any observable becomes diagonal in the eigenstates of the total Hamiltonian for systems endowed with a continuous energy spectrum, and (2), that this process can be interpreted as decoherence. We evaluate the first claim in the context of a simple spin bath model. We find that even for large environments, corresponding to an approximately continuous energy spectrum, diagonalization of the expectation value of random observables does in general not occur. We explain this result and conjecture that SID is likely to fail also in other systems composed of discrete subsystems. Regarding the second claim, we emphasize that SID does not describe a physically meaningful decoherence process for individual measurements, but only involves destructive interference that occurs collectively within an ensemble of presupposed "values" of measurements. This leads us to question the relevance of SID for treating observed decoherence effects.Comment: 11 pages, 4 figures. Final published versio

Information Transfer Implies State Collapse

We attempt to clarify certain puzzles concerning state collapse and decoherence. In open quantum systems decoherence is shown to be a necessary consequence of the transfer of information to the outside; we prove an upper bound for the amount of coherence which can survive such a transfer. We claim that in large closed systems decoherence has never been observed, but we will show that it is usually harmless to assume its occurrence. An independent postulate of state collapse over and above Schroedinger's equation and the probability interpretation of quantum states, is shown to be redundant.Comment: 13 page

Production and use of metals and oxygen for lunar propulsion

Production, power, and propulsion technologies for using oxygen and metals derived from lunar resources are discussed. The production process is described, and several of the more developed processes are discussed. Power requirements for chemical, thermal, and electrical production methods are compared. The discussion includes potential impact of ongoing power technology programs on lunar production requirements. The performance potential of several possible metal fuels including aluminum, silicon, iron, and titanium are compared. Space propulsion technology in the area of metal/oxygen rocket engines is discussed

Mean-Field Dynamics: Singular Potentials and Rate of Convergence

We consider the time evolution of a system of $N$ identical bosons whose interaction potential is rescaled by $N^{-1}$. We choose the initial wave function to describe a condensate in which all particles are in the same one-particle state. It is well known that in the mean-field limit $N \to \infty$ the quantum $N$-body dynamics is governed by the nonlinear Hartree equation. Using a nonperturbative method, we extend previous results on the mean-field limit in two directions. First, we allow a large class of singular interaction potentials as well as strong, possibly time-dependent external potentials. Second, we derive bounds on the rate of convergence of the quantum $N$-body dynamics to the Hartree dynamics.Comment: Typos correcte

Loschmidt Echo and Berry phase of the quantum system coupled to the XY spin chain: Proximity to quantum phase transition

We study the Loschmidt echo (LE) of a coupled system consisting of a central spin and its surrounding environment described by a general XY spin-chain model. The quantum dynamics of the LE is shown to be remarkably influenced by the quantum criticality of the spin chain. In particular, the decaying behavior of the LE is found to be controlled by the anisotropy parameter of the spin chain. Furthermore, we show that due to the coupling to the spin chain, the ground-state Berry phase for the central spin becomes nonanalytical and its derivative with respect to the magnetic parameter $\lambda$ in spin chain diverges along the critical line $\lambda=1$, which suggests an alternative measurement of the quantum criticality of the spin chain.Comment: 15 pages, 5 figure