A STRATEGIC RATIONALE FOR CAPTIVE SUPPLIES

Partial backward integration is prevalent in many agricultural and natural resource processing industries. A strategic rationale for partial backward integration is developed for a dominant firm with a competitive fringe purchasing from competitive input suppliers. A partially backward integrated dominant firm potentially can increase profit through production efficiency gains and through a lower price for externally purchasing input. The optimal degree of backward integration results when the dominant firm's profit from exerting monopsony market power in the external spot market equals its profit from producing raw input internally, less the incremental cost of acquiring internal raw input production capacity. Comparative statics results are consistent with recent empirical studies of the beef packing industry.Agribusiness,

A RATIONALE FOR CAPTIVE SUPPLIES

Captive supplies, concentration, meat industry, poultry industry, Agribusiness,

A REVIEW OF ALTERNATIVE EXPECTATIONS REGIMES IN COMMODITY MARKETS: SPECIFICATION, ESTIMATION, AND HYPOTHESIS TESTING USING STRUCTURAL MODELS

Price expectations play a critical role in commodity markets where producers must make input decisions well before output is realized. This paper brings together alternative expectations regimes, their estimation, and hypothesis tests for use in structural commodity models to determine their use by commodity producers. Extrapolative mechanisms and rational expectations are considered under risk neutrality and risk aversion. The assumptions implicit in the use of aggregate data in these models are made explicit. Structural models using individual survey data are discussed. While Muth's rational expectations hypothesis has found widespread acceptance in the macroeconomic literature, empirical results from industry studies indicate that commodity producers may have heterogeneous price expectations, with no single expectations hypothesis dominating. This is not surprising given that different producers possess different information and have different costs associated with information collection and processing.Demand and Price Analysis,

ANALYSIS OF THE EFFECTS OF ENVIRONMENTAL REGULATION ON PULP AND PAPER INDUSTRY STRUCTURE

Environmental regulations are hypothesized to have an impact on industry structure in manufacturing industries. A nonstationary Markov chain analysis shows that the capital expenditures required to meet environmental regulations is a statistically significant variable explaining increasing concentration of production capacity in the pulp and paper industry.Environmental Economics and Policy, Research Methods/ Statistical Methods,

Triangular buckling patterns of twisted inextensible strips

When twisting a strip of paper or acetate under high longitudinal tension, one observes, at some critical load, a buckling of the strip into a regular triangular pattern. Very similar triangular facets have recently been observed in solutions to a new set of geometrically-exact equations describing the equilibrium shape of thin inextensible elastic strips. Here we formulate a modified boundary-value problem for these equations and construct post-buckling solutions in good agreement with the observed pattern in twisted strips. We also study the force-extension and moment-twist behaviour of these strips by varying the mode number n of triangular facets

Sudden collapse of a colloidal gel

Metastable gels formed by weakly attractive colloidal particles display a distinctive two-stage time-dependent settling behavior under their own weight. Initially a space-spanning network is formed that for a characteristic time, which we define as the lag time \taud, resists compaction. This solid-like behavior persists only for a limited time. Gels whose age \tw is greater than \taud yield and suddenly collapse. We use a combination of confocal microscopy, rheology and time-lapse video imaging to investigate both the process of sudden collapse and its microscopic origin in an refractive-index matched emulsion-polymer system. We show that the height $h$ of the gel in the early stages of collapse is well described by the surprisingly simple expression, h(\ts) = \h0 - A \ts^{3/2}, with \h0 the initial height and \ts = \tw-\taud the time counted from the instant where the gel first yields. We propose that this unexpected result arises because the colloidal network progressively builds up internal stress as a consequence of localized rearrangement events which leads ultimately to collapse as thermal equilibrium is re-established.Comment: 14 pages, 11 figures, final versio

The Potential Impact of Ice-Minus Bacteria As A Frost Protectant in New York Tree Fruit Production

A.E. Res. 88-1

Beef Cattle Lesson Plans: For use in the education of school-age children in the beef cattle industry

This project was initially created for use at Fort Hope in Arroyo Grande, California. It designs lesson plans created to teach children about the beef cattle industry. The project consists of lesson plans for three age groups: 7-9, 10-12, and 13-15. Each age group will learn various aspects about beef cattle, and lessons will increase in complexity as the children advance age groups. The groups will spend six days in lecture completing worksheets and activities, and on the seventh day, after completion of a review game, the children receive certificates. While the project was created specifically for the Fort Hope curriculum, it may be adapted for other uses

Discrete elastic model for stretching-induced flagellar polymorphs

Force-induced reversible transformations between coiled and normal polymorphs of bacterial flagella have been observed in recent optical-tweezer experiment. We introduce a discrete elastic rod model with two competing helical states governed by a fluctuating spin-like variable that represents the underlying conformational states of flagellin monomers. Using hybrid Brownian dynamics Monte-Carlo simulations, we show that a helix undergoes shape transitions dominated by domain wall nucleation and motion in response to externally applied uniaxial tension. A scaling argument for the critical force is presented in good agreement with experimental and simulation results. Stretching rate-dependent elasticity including a buckling instability are found, also consistent with the experiment

Soft modes near the buckling transition of icosahedral shells

Icosahedral shells undergo a buckling transition as the ratio of Young's modulus to bending stiffness increases. Strong bending stiffness favors smooth, nearly spherical shapes, while weak bending stiffness leads to a sharply faceted icosahedral shape. Based on the phonon spectrum of a simplified mass-and-spring model of the shell, we interpret the transition from smooth to faceted as a soft-mode transition. In contrast to the case of a disclinated planar network where the transition is sharply defined, the mean curvature of the sphere smooths the transitition. We define elastic susceptibilities as the response to forces applied at vertices, edges and faces of an icosahedron. At the soft-mode transition the vertex susceptibility is the largest, but as the shell becomes more faceted the edge and face susceptibilities greatly exceed the vertex susceptibility. Limiting behaviors of the susceptibilities are analyzed and related to the ridge-scaling behavior of elastic sheets. Our results apply to virus capsids, liposomes with crystalline order and other shell-like structures with icosahedral symmetry.Comment: 28 pages, 6 figure