165 research outputs found
The price stabilization effects of the EU entry price scheme for fruits and vegetables
The paper assesses the stabilization effects of the EU import regime for fresh fruit and vegetables based on the entry price system. The analysis is carried out on the EU prices of tomatoes and lemons and those of imports from some of the main competing countries on the EU domestic markets: Morocco, Argentina and Turkey. It is based on the estimation of a threshold vector autoregressive econometric model that is shown capable of taking the workings of the import regime into account. The model shows that prices behave differently when import prices are above/below the trigger entry price. This paper allowed to highlight the cases for which the isolation effect of EPS seems reached and the resulting stabilization effects
State-space approach to evaluate spatial variability of field measured soil water status along a line transect in a volcanic-vesuvian soil
Abstract. Unsaturated hydraulic properties and their spatial variability today are analyzed in order to use properly mathematical models developed to simulate flow of the water and solute movement at the field-scale soils. Many studies have shown that observations of soil hydraulic properties should not be considered purely random, given that they possess a structure which may be described by means of stochastic processes. The techniques used for analyzing such a structure have essentially been based either on the theory of regionalized variables or to a lesser extent, on the analysis of time series. This work attempts to use the time-series approach mentioned above by means of a study of pressure head h and water content θ which characterize soil water status, in the space-time domain. The data of the analyses were recorded in the open field during a controlled drainage process, evaporation being prevented, along a 50 m transect in a volcanic Vesuvian soil. The isotropic hypothesis is empirical proved and then the autocorrelation ACF and the partial autocorrelation functions PACF were used to identify and estimate the ARMA(1,1) statistical model for the analyzed series and the AR(1) for the extracted signal. Relations with a state-space model are investigated, and a bivariate AR(1) model fitted. The simultaneous relations between θ and h are considered and estimated. The results are of value for sampling strategies and they should incite to a larger use of time and space series analysis
The price stabilization effects of the EU entry price scheme for fruits and vegetables
The paper assesses the stabilization effects of the EU import regime for fresh fruit and vegetables based on the entry price system. The analysis is carried out on the EU prices of tomatoes and lemons and those of imports from some of the main competing countries on the EU domestic markets: Morocco, Argentina and Turkey. It is based on the estimation of a threshold vector autoregressive econometric model that is shown capable of taking the workings of the import regime into account. The model shows that prices behave differently when import prices are above/below the trigger entry price. This paper allowed to highlight the cases for which the isolation effect of EPS seems reached and the resulting stabilization effects.Fruit and vegetables; Entry price system; stabilisation effects; TVAR
The Price Stabilisation Effects of the EU import regime of fruit and vegetables: the case of tomatoes
The paper assesses the stabilization effects of the EU import regime for fresh fruit and vegetables based on the entry price system. The analysis is carried out on the EU prices of tomatoes and those of imports from Morocco, the main competing country on the EU domestic markets. It is based on the estimation of a threshold vector autoregressive econometric model that is shown capable of taking the workings of the import regime into account. The model shows that when prices of tomato imports are below the trigger entry prices the EU tomato market becomes isolated. However, the contribution of the import regime on price stabilization is rather limited. Since tomato imports from Morocco are granted zero tariff if their price is higher than the trigger entry price within a yearly quota that is completely filled, the largest contribution to market stabilization may well come from the size of the quota.fruit and vegetables, European Union , entry prices, trade preferences, price stabilization , tomatoes
The price stabilization effects of the EU entry price scheme for fruit and vegetables
The article assesses the stabilization effects of the EU import regime for fresh fruit and vegetables based on the entry price system (EPS). The analysis is carried out on the EU prices of tomatoes and lemons and those of imports from some of the main competing countries on the EU domestic markets: Morocco, Argentina, and Turkey. It is based on the estimation of a threshold vector autoregressive econometric model that is shown capable of taking the workings of the import regime into account. The model shows that prices behave differently when import prices are above/below the trigger entry price. This article allowed to highlight the cases for which the isolation effect of EPS seems reached and the resulting stabilization effects. © 2011 International Association of Agricultural Economists
Incorporation of Natural and Recombinant Collagen Proteins within Fmoc-Based Self-Assembling Peptide Hydrogels
Hydrogel biomaterials mimic the natural extracellular matrix through their nanofibrous ultrastructure and composition and provide an appropriate environment for cell–matrix and cell–cell interactions within their polymeric network. Hydrogels can be modified with different proteins, cytokines, or cell-adhesion motifs to control cell behavior and cell differentiation. Collagens are desirable and versatile proteins for hydrogel modification due to their abundance in the vertebrate extracellular matrix and their interactions with cell-surface receptors. Here, we report a quick, inexpensive and effective protocol for incorporation of natural, synthetic and recombinant collagens into Fmoc-based self-assembling peptide hydrogels. The hydrogels are modified through a diffusion protocol in which collagen molecules of different molecular sizes are successfully incorporated and retained over time. Characterization studies show that these collagens interact with the hydrogel fibers without affecting the overall mechanical properties of the composite hydrogels. Furthermore, the collagen molecules incorporated into the hydrogels are still biologically active and provide sites for adhesion and spreading of human fibrosarcoma cells through interaction with the α2β1 integrin. Our protocol can be used to incorporate different types of collagen molecules into peptide-based hydrogels without any prior chemical modification. These modified hydrogels could be used in studies where collagen-based substrates are required to differentiate and control the cell behavior. Our protocol can be easily adapted to the incorporation of other bioactive proteins and peptides into peptide-based hydrogels to modulate their characteristics and their interaction with different cell types
General role of the amino and methylsulfamoyl groups in selective cyclooxygenase(COX)-1 inhibition by 1,4-diaryl-1,2,3-triazoles and validation of a predictive pharmacometric PLS model
A novel set of 1,4-diaryl-1,2,3-triazoles were projected as a tool to study the effect of both the heteroaromatic triazole as a core ring and a variety of chemical groups with different electronic features, size and shape on the catalytic activity of the two COX isoenzymes. The new triazoles were synthesized in fair to good yields and then evaluated for their inhibitory activity towards COXs arachidonic acid conversion catalysis. Their COXs selectivity was also measured. A predictive pharmacometric Volsurf plus model, experimentally confirmed by the percentage (%) of COXs inhibition at the concentration of 50 ÎĽM and IC50 values of the tested compounds, was built by using a number of isoxazoles of known COXs inhibitory activity as a training set. It was found that two compounds {4-(5-methyl-4-phenyl-1H-1,2,3-triazol-1-yl)benzenamine (18) and 4-[1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole-4-yl]benzenamine (19)} bearing an amino group (NH2) are potent and selective COX-1 inhibitors (IC50 Combining double low line 15 and 3 ÎĽM, respectively) and that the presence of a methylsulfamoyl group (SO2CH3) is not a rule to have a Coxib. In fact, 4-(4-methoxyphenyl)-5-methyl-1-[4-(methylsulfonyl)phenyl]-1H-1,2,3-triazole (23) has COX-1 IC50 Combining double low line 23 ÎĽM and was found inactive towards COX-2
The Price Stabilisation Effects of the EU import regime of fruit and vegetables: the case of tomatoes
The paper assesses the stabilization effects of the EU import regime for fresh fruit and vegetables based
on the entry price system. The analysis is carried out on the EU prices of tomatoes and those of imports
from Morocco, the main competing country on the EU domestic markets. It is based on the estimation of
a threshold vector autoregressive econometric model that is shown capable of taking the workings of the
import regime into account. The model shows that when prices of tomato imports are below the trigger
entry prices the EU tomato market becomes isolated. However, the contribution of the import regime on
price stabilization is rather limited. Since tomato imports from Morocco are granted zero tariff if their
price is higher than the trigger entry price within a yearly quota that is completely filled, the largest
contribution to market stabilization may well come from the size of the quota
- …