Perfiles de ácidos grasos de aceites de oliva virgen (Olea europaea L.) de huertos en plena producción en los valles cálidos áridos del noroeste de Argentina (La Rioja)

The olive industry in Northwestern Argentina has experienced substantial growth during the past two decades to produce virgin olive oil for export. To assess the fatty acid profiles of the main varietal olive oils, 563 oil samples from 17 varieties cultivated in the province of La Rioja were analyzed from 2005-2008. Olive varieties were ranked according to oleic acid content as low (65%; Manzanilla, Empeltre, Leccino, Coratina, Changlot, Picual). Using data from this study and the literature, the fatty acid composition of Spanish (Arbequina, Picual) and Italian (Coratina, Frantoio) varieties indicated consistently lower oleic acid contents when grown in NW Argentina versus the Mediterranean. For Arbequina, the oleic content decreased with increasing temperature during oil accumulation (-2% per °C). The classification of varieties should be useful in the selection of virgin olive oils for corrective blending and for choosing varieties for new orchards in order to meet IOOC requirements. The differences in fatty acid composition between NW Argentina and the Mediterranean Basin are most likely to be related to a genotype produced by environmental interaction, and the negative effect of the high seasonal mean temperature during oil accumulation will need further research.La industria oleícola del noroeste de Argentina creció sustancialmente durante las últimas dos décadas para producir aceite de oliva virgen exportable. Para evaluar el perfil de ácidos grasos de los principales aceites varietales, se analizaron 563 muestras de aceite de 17 variedades en la provincia de La Rioja durante 2005-2008. Las variedades se clasificaron de acuerdo a su contenido de ácido oleico en bajo (65%; Manzanilla, Empeltre, Leccino, Coratina, Changlot, Picual). Utilizando datos de este trabajo y de la literatura, los aceites de variedades de origen español (Arbequina y Picual) e italiano (Coratina y Frantoio) mostraron consistentemente menor contenido de ácido oleico cuando crecieron en el noroeste de Argentina versus el Mediterráneo. Para Arbequina, el contenido de oleico disminuyó con la temperatura durante la síntesis y acumulación lipídica (-2 % por °C). La clasificación varietal por acido oleico debe ser útil para seleccionar aceites para mezclas correctivas y variedades para futuras plantaciones que cumplan con la normativa del COI. Diferencias en los perfiles de ácidos grasos entre el noroeste de Argentina y el Mediterráneo indican una interacción genotipo x ambiente, y el efecto negativo de la alta temperatura media estacional durante la síntesis de lípidos requerirá mayor investigación

Estandarización nacional del método de conductividad eléctrica para analizar el vigor de semillas en girasol

Objetivos del IIPAAS: Objetivo general: Validar a nivel nacional el test de conductividad eléctrica para medir el vigor en semillas de girasol. Objetivos específicos: 1. Confirmar la clasificación del vigor en base al test de CE propuesta en los estudios precedentes. 2. Evaluar la exactitud, reproducibilidad y repetibilidad del test de CE entre y dentro de los laboratorios participantes. 3. Confeccionar un protocolo nacional como paso previo para ser propuesto al Comité de Vigor de la ISTA

An experimental and theoretical investigation of a magnetically confined dc plasma discharge

A magnetically confined dc plasma discharge sustained by a thermionic source was investigated using a combined experimental and theoretical approach. The discharge originates in an arc plasma source and is expanded in a cylindrical chamber, where it is stabilized by an annular anode. The plasma expansion is contained by an axial magnetic field generated by coils positioned at the top and the bottom of the reactor. The plasma reactor design allows control of the energy of ions impinging on the substrate and thus a high electron density of about 1017 m−3 at 1 Pa can be reached. The plasma is studied using a model composed of the Poisson and of the charged species continuity equations, solved in the flow and temperature fields determined by solving the Navier–Stokes and Fourier equations. The model equations are integrated using the finite element method in a two-dimensional axial symmetric domain. Ionization rates are either assumed constant or determined by solving the Boltzmann transport equation in the local electric field with the Monte Carlo ͑MC͒ method. Electron and ion transport parameters are determined by accounting for magnetic confinement through a simplified solution of the ion and electron momentum conservation equations, which yielded parameters in good agreement with those determined with the MC simulations. Calculated electron densities and plasma potentials were satisfactorily compared to those measured using a Langmuir probe. The model demonstrates that the intensity of the magnetic field greatly influences the electron density, so that a decrease by a factor of 2 in its intensity corresponds to a decrease by almost an order of magnitude of the electron and ion concentrations