EVALUATING FARMLAND INVESTMENTS CONSIDERING DYNAMIC STOCHASTIC RETURNS AND FARMLAND PRICES

This paper examines farmland investment decisions using a stochastic dynamic programming framework. Consideration is given to the dynamic, stochastic nature of farmland returns, linkages between farmland returns and farmland prices, and the effects of the above dynamic factors on a farmÂ’s financial structure. Optimal decisions to purchase or sell farmland are found for a central Illinois farm with high quality farmland. Sizes and debt distributions are then determined, given that the optimal decision rule is followed. Decisions from the dynamic programming model also are compared to a capital budgeting model.Land Economics/Use,

Probabilistic Models of Yield, Price, and Revenue Risks for Fed Cattle Production

Livestock Production/Industries,

Adapting the International System of Units to the twenty-first century

We review the proposal of the International Committee for Weights and Measures (Comité International des Poids et Mesures, CIPM), currently being considered by the General Conference on Weights and Measures (Conférences Générales des Poids et Mesures, CGPM), to revise the International System of Units (Le Système International d’Unitès, SI). The proposal includes new definitions for four of the seven base units of the SI, and a new form of words to present the definitions of all the units. The objective of the proposed changes is to adopt definitions referenced to constants of nature, taken in the widest sense, so that the definitions may be based on what are believed to be true invariants. In particular, whereas in the current SI the kilogram, ampere, kelvin and mole are linked to exact numerical values of the mass of the international prototype of the kilogram, the magnetic constant (permeability of vacuum), the triple-point temperature of water and the molar mass of carbon-12, respectively, in the new SI these units are linked to exact numerical values of the Planck constant, the elementary charge, the Boltzmann constant and the Avogadro constant, respectively. The new wording used expresses the definitions in a simple and unambiguous manner without the need for the distinction between base and derived units. The importance of relations among the fundamental constants to the definitions, and the importance of establishing a mise en pratique for the realization of each definition, are also discussed

Universal response pattern of phytoplankton growth rates to increasing CO 2

Phytoplankton growth rate is a key variable controlling species succession and ecosystem structure throughout the surface ocean. Carbonate chemistry conditions are known to influence phytoplankton growth rates but there is no conceptual framework allowing us to compare growth rate responses across taxa. Here we analyse the literature to show that phytoplankton growth rates follow an optimum curve response pattern whenever the tested species is exposed to a sufficiently large gradient in proton (H+) concentrations. Based on previous findings with coccolithophores and diatoms, we argue that this ‘universal reaction norm’ is shaped by the stimulating influence of increasing inorganic carbon substrate (left side of the optimum) and the inhibiting influence of increase H+ (right side of the optimum). We envisage that exploration of carbonate chemistry-dependent optimum curves as a default experimental approach will boost our mechanistic understanding of phytoplankton responses to ocean acidification, like temperature curves have already boosted our mechanistic understanding to global warming

Flowering During January in Antigonish County, Nova Scotia

Over 85 records of 23 species of blooming, herbaceous angiosperms were made at 19 sites in Antigonish County between 7 and 21 January 2006, when daytime temperatures reached 15°C. These observations followed an unusually warm fall and early winter. All species were observed on waste ground or in fields and garden plots, except for Epigaea repens L. which was part of ground vegetation in a sparsely wooded site. The primary families represented were Asteraceae (six species), Brassicaceae (six species) and Carophyllaceae (four species). The most commonly observed plants were Taraxacum officinale (L.) Weber (11 sites), Capsella bursa-pastoris (L.) Medik. (nine sites), Thlaspi arvense L. (three sites) and Stellaria media (L.) Vill. (four sites). Many plants and inflorescences were conspicuously frost-damaged, and flowers were rarely fully open. In several species, e.g., T. arvense and Cerastium vulgatum L., many individual plants looked normal and there was no evidence of frost damage. These observations are the latest flowering records for Nova Scotia

Longitudinal analysis of sleep in relation to BMI and body fat in children: the FLAME study

Objectives To determine whether reduced sleep is associated with differences in body composition and the risk of becoming overweight in young children