Nonlinear Price Transmission in Wheat Export Prices

This paper attempts to model the price relationship between the major exporters of wheat. The motivation of such research is to reveal whether prices are integrated and whether potential nonlinearities in price adjustment exist. Given the perception that transactions costs may be highly variable in the wheat market, the paper aims to test for the presence of cointegration in the presence of smooth transition adjustment. The results conclude that the further the prices deviate from each other, the larger will be the arbitrage and substitution that will drive the prices close to each other. However, the results suggest that the arbitrage will be limited as the various wheat prices employed in this study may be linked to highly variable transactions costs or some other form of imperfect competition.price adjustment; estar; wheat; cointegration

Asymmetric price adjustment of Ukrainian feed wheat export prices in relation to U.S. maize exports: A Note

This note aims to investigate the price dynamics between Ukrainian feed wheat exports and U.S. maize exports employing the method by Enders and Siklos (2001) to allow for threshold adjustment. The analysis reveals slow amounts of adjustment towards equilibrium for a positive change in the equilibrium relationship, but a substantial amount of adjustment for a negative change in the equilibrium relationship. This would imply that Ukrainian prices would have to decrease at a faster rate in order to retain their market share. The fact that there is some evidence of asymmetric price adjustment is not surprising given that Ukraine is a minor exporter in relation to the U.S. and that policy intervention exists in the Ukrainian wheat market. The nature of price dynamics sheds light on how Ukraine has been strategically responding to U.S. maize exports since the mid 1990s.Wheat.

Long-Run Relationship of U.S. and Argentine Maize Prices

This paper examines the relationship between the maize export prices of the United States and Argentina. The results suggest an asymmetric nature of price adjustment. This could be due to the fact that the maize market is characterized by significant concentration. The larger market share of exports by the United States reflects the influences on export price dynamics. The structure of maize trade is such that U.S. markets are largely insulated from influences flowing from Argentina, while Argentine maize prices are not insulated from U.S. influences.cointegration, maize, price dynamics, threshold adjustment, Demand and Price Analysis, International Relations/Trade,

Entanglement entropy of a three-spin interacting spin chain with a time-reversal breaking impurity at one boundary

We investigate the effect of a time-reversal breaking impurity term on both the equilibrium and non-equilibrium critical properties of entanglement entropy (EE) in a three-spin interacting transverse Ising model which can be mapped to a one-dimensional p-wave superconductor with next-nearest-neighbor hopping. Due to the presence of next-nearest-neighbor hopping, a new topological phase with two zero-energy Majorana modes at each end of an open chain appears in the phase diagram. We show that the derivative of EE with respect to one of the parameters of the Hamiltonian can detect the quantum phase transitions by exhibiting cusp like structure at those points; impurity strength (\la_d) can substantially modify the peak/dip height associated with the cusp. Importantly, we find that the logarithmic scaling of the EE with block size remains unaffected by the application of the impurity term, although, the coefficient (i.e., central charge) varies logarithmically with the impurity strength for a lower range of \la_d and eventually saturates with an exponential damping factor (\sim \exp(-\la_d)) for the phase boundaries shared with the phase containing two Majorana edge modes. On the other hand, it receives a linear correction in term of \la_d for an another phase boundary. Finally, we focus to study the effect of the impurity in the time evolution of the EE for the critical quenching case where impurity term is applied only to the final Hamiltonian. Interestingly, it has been shown that for all the phase boundaries in contrary to the equilibrium case, the saturation value of the EE increases logarithmically with the strength of impurity in a certain region of \la_d and finally, for higher values of \la_d, it increases very slowly which is dictated by an exponential damping factor.Comment: 10 pages, 10 figure