Price transmission analysis: A flexible methodological approach applied to European hog markets

The study of spatial price relationships contributes to explain markets performance, their degree of integration or isolation, and the speed at which information is transmitted. A great deal of methods have been used to analyze this issue, being the most important: causality tests, impulse- response functions and cointegration. Normally, these techniques have been individually applied. However, a more rich knowledge of the functioning of markets can be extracted when they are jointly applied. In this paper, we try to conjugate these three techniques in a common econometric model. First, Johansen(1988) multivariate cointegration tests are used to determine the number of long-run equilibrium relationships. Cointegration is considered not only as informative about long-run price transmission but also as an essential step in the correct specification of a vector error correction model (VECM) used in the subsequent analysis. Second, Dolado and Lutkepohl(1996) causality tests are used to investigate the lead-lag behaviour among markets. Finally, impulse-response functions are calculated from the VECM estimated in the first stage for evaluating dynamic price linkages. The method exposed is applied to study spatial pork prices relationships among seven countries in the EU from 1988 to 1995. Weekly prices at farm level published by EUROSTAT: "Agricultural Markets" are used.

Ethnic food preferences in the Spanish market

A labelled choice experiment is conducted in order to investigate preferences of Spanish consumers towards ethnic cuisines. In particular, the three best known cuisines, Mexican, Arab and Asian, are considered, across three consumption situations: restaurant, take-away and at home. Wald statistics are applied in order to assess the differential marginal utilities of ethnic food in alternative consumption situations, and the appropriateness of considering a linear effect in price.choice experiment, ethnic food, consumers, Food Consumption/Nutrition/Food Safety,

Experimental evidence for vibrational resonance and enhanced signal transmission in Chua's circuit

We consider a single Chua's circuit and a system of a unidirectionally coupled n-Chua's circuits driven by a biharmonic signal with two widely different frequencies \omega and \Omega, where \Omega >> \omega. We show experimental evidence for vibrational resonance in the single Chua's circuit and undamped signal propagation of a low-frequency signal in the system of n-coupled Chua's circuits where only the first circuit is driven by the biharmonic signal. In the single circuit, we illustrate the mechanism of vibrational resonance and the influence of the biharmonic signal parameters on the resonance. In the n(= 75)-coupled Chua's circuits enhanced propagation of low-frequency signal is found to occur for a wide range of values of the amplitude of the high-frequency input signal and coupling parameter. The response amplitude of the ith circuit increases with i and attains a saturation. Moreover, the unidirectional coupling is found to act as a low-pass filter.Comment: 15 pages, 12 figures, Accepted for Publication in International Journal of Bifurcation and Chao

Design and 3D printing of an electrochemical sensor for Listeria monocytogenes detection based on loop mediated isothermal amplification

The aim of this work is the design and 3D printing of a new electrochemical sensor for the detection of Listeria monocytogenes based on loop mediated isothermal amplification (LAMP). The food related diseases involve a serious health issue all over the world. Listeria monocytogenes is one of the major problems of contaminated food, this pathogen causes a disease called listeriosis with a high rate of hospitalization and mortality. Having a fast, sensitive and specific detection method for food quality control is a must in the food industry to avoid the presence of this pathogen in the food chain (raw materials, facilities and products). A point-of-care biosensor based in LAMP and electrochemical detection is one of the best options to detect the bacteria on site and in a very short period of time. With the numerical analysis of different geometries and flow rates during sample injection in order to avoid bubbles, an optimized design of the microfluidic biosensor chamber was selected for 3D-printing and experimental analysis. For the electrochemical detection, a novel custom gold concentric-3-electrode consisting in a working electrode, reference electrode and a counter electrode was designed and placed in the bottom of the chamber. The LAMP reaction was optimized specifically for a primers set with a limit of detection of 1.25 pg of genomic DNA per reaction and 100% specific for detecting all 12 Listeria monocytogenes serotypes and no other Listeria species or food-related bacteria. The methylene blue redox-active molecule was tested as the electrochemical transducer and shown to be compatible with the LAMP reaction and very clearly distinguished negative from positive food samples when the reaction is measured at the end-point inside the biosensor

Physicochemical characterization of hydrophobic type III and type V deep eutectic solvents based on carboxylic acids

In the present work, novel type III and type V deep eutectic solvents (DESs) were prepared by mixing choline chloride (ChCl), tetrabutylammonium chloride (TBAC) or thymol as HBA, and different alkyl chain length carboxylic acids as HBD (acetic, oxalic, palmitic, stearic, oleic and linoleic acid) at various molar ratios. The hydrophobic DESs were characterized by infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR), concluding the formation of intermolecular interactions, as hydrogen bonds between the precursors. Thermogravimetric analysis (TGA) was used to obtain the thermal decomposition profiles of the prepared DESs, proving interactions between the precursors and decomposition temperatures with values, which are found in the ranges of the precursor constituents and higher than 170 °C. Other physicochemical properties, such as density, thermal expansion coefficient, dynamic viscosity, refractive index, surface tension, and thermal and ionic conductivities have been determined. Furthermore, the ability of these DESs as UV filter extractants from aqueous samples using a dispersive liquid–liquid microextraction (DLLME) previous to liquid chromatographic analysis was demonstrated. Therefore, these type III and type V DESs could be applied to the extraction of pollutants from environmental water samples

Structural determinants for NF-Y/DNA interaction at the CCAAT box

The recently determined crystal structures of the sequence-specific transcription factor NF-Y have illuminated the structural mechanism underlying transcription at the CCAAT box. NF-Y is a trimeric protein complex composed by the NF-YA, NF-YB, and NF-YC subunits. NF-YB and NF-YC contain a histone-like domain and assemble on a head-to-tail fashion to form a dimer, which provides the structural scaffold for the DNA sugar-phosphate backbone binding (mimicking the nucleosome H2A/H2B\ue2\u80\u93DNA assembly) and for the interaction with NF-YA. The NF-YA subunit hosts two structurally extended \uce\ub1-helices; one is involved in NF-YB/NF-YC binding and the other inserts deeply into the DNA minor groove, providing exquisite sequence-specificity for recognition and binding of the CCAAT box. The analysis of these structural data is expected to serve as a powerful guide for future experiments aimed at understanding the role of post-translational modification at NF-Y regulation sites and to unravel the three-dimensional architecture of higher order complexes formed between NF-Y and other transcription factors that act synergistically for transcription activation. Moreover, these structures represent an excellent starting point to challenge the formation of a stable hybrid nucleosome between NF-Y and core histone proteins, and to rationalize the fine molecular details associated with the wide combinatorial association of plant NF-Y subunits