The Impact of Drought on Grain Handling Firms

Drought impact both producers and agribusinesses. This study investigates the impacts of the 2004-2007 droughts on Oklahoma grain handling and fertilizer supply firms. The results indicated an average decline in firm revenues of 30%. Individual firms had single year revenue declines of 85% and drought period declines of 75%.Agribusiness, Environmental Economics and Policy,

Investigation of the Costs of an Increased Shipping Standard for Cotton Warehouses

The speed of shipping cotton from warehouses has become an important issue for the cotton industry. This paper examines issues relating to costs and benefits of an increased cotton shipping standard. The value chain model is used to identify improvements in incentives, information flow and warehouse filling and management strategies.Industrial Organization,

Optimal Cash Purchase Strategies to Reduce Fertilizer Price Risk

Fertilizer price volatility has increased dramatically. This research examines cash purchase and warehouse strategies. Seventeen years of Oklahoma fertilizer prices are examined. The results indicate that mechanical cash purchase strategies can be used to reduce the average cost or variance for fertilizer. Optimal purchase dates are also identified.fertilizer, price risk, seasonal price pattern, Agribusiness, Crop Production/Industries, Farm Management,

Reflections on the Journal of Cooperatives 1986-2003

The Journal of Cooperatives (formally titled the Journal of Agricultural Cooperation) was published as a print journal from 1986 to 2003. The journal resumed publication as an electronic journal in 2007. This article provides a short history of the journal, analyzes trends in authorship, institution, content, research method and intended audience, and considers issues relating to electronic publication. The journal’s historical and current mission statements are also discussed, and a future thrust for the journal is presented.Cooperative, academic journal, electronic publishing, Teaching/Communication/Extension/Profession,

Estimation of Efficiency with the Stochastic Frontier Cost Function and Heteroscedasticity: A Monte Carlo Study

The objective of this article is to address heteroscedasticity in the stochastic frontier cost function using aggregated data and verify it using a Monte Carlo study. We find that when the translog form of a stochastic frontier cost function with aggregated data is estimated, all explanatory variables can inversely affect the variation of error terms. Our Monte Carlo study shows that heteroscedasticity is only significant in the random effect and the unexplained error term not in the inefficiency error term. Also, it does not cause biases, which is quite opposite of previous research. These are because our model is approximately defined by first order Taylor series around zero inefficiency area. But, disregarding heteroscedasticity causes the average inefficiency to be overestimated when the variation of inefficiency term dominates the other error terms.Resource /Energy Economics and Policy,

Stability analysis of f(R)-AdS black holes

We study the stability of f(R)-AdS (Schwarzschild-AdS) black hole obtained from f(R) gravity. In order to resolve the difficulty of solving fourth order linearized equations, we transform f(R) gravity into the scalar-tensor theory by introducing two auxiliary scalars. In this case, the linearized curvature scalar becomes a dynamical scalaron, showing that all linearized equations are second order. Using the positivity of gravitational potentials and S-deformed technique allows us to guarantee the stability of f(R)-AdS black hole if the scalaron mass squared satisfies the Breitenlohner-Freedman bound. This is confirmed by computing quasinormal frequencies of the scalaron for large f(R)-AdS black hole.Comment: 17 pages, 1 figure, version to appear in EPJ

Dynamic Mechanisms of Cell Rigidity Sensing: Insights from a Computational Model of Actomyosin Networks

Cells modulate themselves in response to the surrounding environment like substrate elasticity, exhibiting structural reorganization driven by the contractility of cytoskeleton. The cytoskeleton is the scaffolding structure of eukaryotic cells, playing a central role in many mechanical and biological functions. It is composed of a network of actins, actin cross-linking proteins (ACPs), and molecular motors. The motors generate contractile forces by sliding couples of actin filaments in a polar fashion, and the contractile response of the cytoskeleton network is known to be modulated also by external stimuli, such as substrate stiffness. This implies an important role of actomyosin contractility in the cell mechano-sensing. However, how cells sense matrix stiffness via the contractility remains an open question. Here, we present a 3-D Brownian dynamics computational model of a cross-linked actin network including the dynamics of molecular motors and ACPs. The mechano-sensing properties of this active network are investigated by evaluating contraction and stress in response to different substrate stiffness. Results demonstrate two mechanisms that act to limit internal stress: (i) In stiff substrates, motors walk until they exert their maximum force, leading to a plateau stress that is independent of substrate stiffness, whereas (ii) in soft substrates, motors walk until they become blocked by other motors or ACPs, leading to submaximal stress levels. Therefore, this study provides new insights into the role of molecular motors in the contraction and rigidity sensing of cells

Investigation of the Costs of an Increased Shipping Standard for Cotton Warehouses

The speed of shipping cotton from warehouses has become an important issue for the cotton industry. This paper examines issues relating to costs and benefits of an increased cotton shipping standard. The value chain model is used to identify improvements in incentives, information flow and warehouse filling and management strategies

The Impact of Drought on Grain Handling Firms

Drought impact both producers and agribusinesses. This study investigates the impacts of the 2004-2007 droughts on Oklahoma grain handling and fertilizer supply firms. The results indicated an average decline in firm revenues of 30%. Individual firms had single year revenue declines of 85% and drought period declines of 75%

Optimal Cash Purchase Strategies to Reduce Fertilizer Price Risk

Fertilizer price volatility has increased dramatically. This research examines cash purchase and warehouse strategies. Seventeen years of Oklahoma fertilizer prices are examined. The results indicate that mechanical cash purchase strategies can be used to reduce the average cost or variance for fertilizer. Optimal purchase dates are also identified