Cyttaria hariotii E.Fisch. as a promising source of pullulan and Mn(II)-pullulan complexes for Mn-deficiency remediation in winter cereals

Pullulan, a water-soluble polysaccharide consisting of maltotriose units used in the preparation of edible films and drug delivery, is generally produced from starch by Aureobasidium pullulans (de Bary & Löwenthal) G.Arnaud fungus. In this article, the characterisation of an alternative pullulan source - the stromata of Cyttaria hariotii E.Fisch. fungus - by elemental analysis, infrared spectroscopy and thermal analysis techniques is reported. With a view to a possible valorisation of this pullulan and its derivatives as bioactive formulations in agriculture, low-molecular-weight pullulan (<7 kDa) complexes with Mn(II), suitable for the remediation of Mn-deficiencies in winter cereal by foliar application, were synthesised and characterised by mass spectrometry

Modelling the effects of the anode work function in PPV LED

Transparent conducting oxides are widely used as the transparent electrode in polymer light emitting diodes (PLEDs). The physical properties of these materials and consequently device performance strongly depend on their processing and surface treatment. The injection of charge from the transparent electrode into the polymer layer occurs by tunnelling through a potential barrier from the electrode to molecules close to it. This barrier is influenced by the difference in the relevant energy levels of electrode material and polymer molecules, the external applied potential, the Coulomb potential of the charges present in the polymer layer and the potential of their image charges on the electrodes, and may also be altered by electrode degradation effects. A better understanding of the effect of varying this potential barrier on the functioning of PLED is necessary to achieve further improvements in these applications. Here we present a theoretical study of the influence of changes in the potential barrier at the transparent electrode, on bipolar charge evolution through thin polymer layers, in the absence of defects and impurity states, while the other electrode functions as an ohmic contact. Results of a mesoscopic model provide insight into bipolar charge injection, charge and recombination distribution throughout the polymer layer, and may suggest new materials and processing methods to optimize these optoelectronic devices.FEDER.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência , Tecnologia, Inovação” – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2005; SFRH/BD/22143/2005

Olive ripening and harvest time in portuguese cultivars of “Beira Interior“ region

Portuguese growers of “Beira Interior”, an inland region in the centre of Portugal, start harvesting olives only in late November or December and finish in January and sometimes February. Studies on olive ripening carried out in different groves showed that, in general, oil content (% d.w.) stabilises during November and ripening index rises regularly throughout the sampling period. However, there were some differences among cultivars. The results suggest that harvest can begin from mid- -October to the 1st fortnight of November, according to location, for ‘Galega’, in the 1st fortnight of December for ‘Bical’, in the 1st fortnight of November for ‘Carrasquinha‘ and in the 2nd fortnight of November for ‘Cornicabra’, therefore harvest time should begin long before the traditional time.info:eu-repo/semantics/publishedVersio

Chemostratigraphy of the Pliensbachian, Puesto Araya Formation (Neuquén Basin, Argentina)

In a preliminary attempt to establish an isotope stratigraphy, strontium, carbon and oxygen isotope ratios were determined from marine biogenic carbonates of Pliensbachian age, in the context of scheme of local ammonite Zones correlatable to the European Standard Zonation. Two sections, rio Atuel and arroyo Serrucho, of the mainly siliciclastic Puesto Araya Formation, Neuquen Basin, south-western Mendoza, Argentina, were studied. Specimens of the bivalve genera Weyla Bhom and Gryphaea Lamarck were selected for the isotopic determinations because of their low-Mg calcite original mineralogy and widespread presence. Scanning electron microscopy, X-ray diffraction and X-ray fluorescence spectrometry techniques were used to control the good degree of preservation of most of the biogenic material, as evidenced by pristine fabrics, 100% calcite composition and Sr, Mn and Fe concentrations. Although strontium isotope ratios are slightly scattered, it is possible to compare them with those of the Early Jurassic seawater reference curve. Carbon isotope signals show two relative maxima, correlatable with those recorded for the upper part of the Ibex Zone and the middle part of the Margaritatus Zone in various European sections, indicating the possible global significance of these events. d18O values were found to be unreliable for isotope stratigraphy, as they are largely depleted in comparison to those of coeval unaltered marine carbonates

Late Holocene evolution of the Lower Tagus alluvial plain and heavy metals content: preliminary results

This paper aims to contribute to the fluvial dynamic knowledge of the Lower Tagus during the late Holocene. Two cores were done in selected geomorphological positions at the alluvial plain. Each ten centimeters of sediments were submitted to sedimentological and geochemical analyses in order to identify human contamination by heavy metals, sedimentation rates and environmental changes in the main channel position. The main conclusions are: (1) The witness of the lateral migration of the fluvial channel; (2) The very irregular sedimentation rate, from 3mm per year to 0.1mm per year; (3) The diversified contamination of fluvial sediments and fluvial channels by heavy metals, namely Cu due to cooper sulphate vineyards and Pb due to petrol and Cr from the tanning industries.Este trabajo pretende contribuir al conocimiento de la dinámica fluvial del curso inferior del río Tajo durante el Holoceno final. Se han realizado dos sondeos en lugares seleccionados de la llanura aluvial. Muestras del sedimento obtenidas cada diez centímetros se han analizado con el fin de identificar la contaminación humana con metales pesados, las tasas de sedimentación y posibles cambios en la posición del cauce principal. Las conclusiones más importantes son: (1) La prueba de la existencia de migración lateral del cauce fluvial; (2) La gran irregularidad de la tasa de sedimentación, que varia entre 0,1 y 3mm por año; (3) La variada contaminación de los sedimentos fluviales y de los cauces por metales pesados, especialmente Cu debido a la aplicación de sulfato de cobre en viñedos, Pb debido al petróleo y Cr por las industrias de curtidos.info:eu-repo/semantics/publishedVersio

Development of ternary diagrams for estimating water retention properties using geostatistical approaches

Most pedotransfer functions (PTFs) have adopted soil texture information as the main predictor to estimate soil hydraulic properties, whether inputs are defined in terms of the relative proportion of different grain size particles or texture-based classifications. The objective of this studywas to develop ternary diagrams for estimating soil water retention (θ) at−33 and−1500 kPa matric potentials, corresponding to the field capacity and wilting point, respectively, from particle size distribution using two geostatistical approaches. The texture triangle was divided into a 1% grid of soil texture composition resulting in 4332 different soil textures. Measured soil water retention values determined in 742 soil horizons/layers located in Portugal were then used to develop and validate the hydraulic ternary diagrams. The development subset included two-thirds of the data, and the validation subset the remaining samples. The measured soil water content values were displayed in the ternary diagram according to the coordinates given by the particles size distribution determined in the same soil samples. The volumetric water content values were then predicted for the entire ternary diagram using two different geostatistical interpolation algorithms (ordinary kriging and the empirical best linear unbiased predictor). Uncertainty analysis resulted in a root mean square error below 0.040 and 0.034 cm3 cm−3 when comparing the interpolated water contents at −33 and −1500 kPa matric potential values, respectively, with the measured ones included in the validation dataset. The estimation variance calculated with both methods was also considered to access the uncertainty of the predictions. The available water content of Portuguese soils was then derived from θ−33 kPa and θ−1500 kPa ternary diagrams developed with both approaches. The hydraulic ternary diagrams may thus serve as simplified tools for estimating water retention properties from particle size distribution and eventually serve as an alternative to the traditional statistical regression and data mining techniques used to derive PTFsinfo:eu-repo/semantics/publishedVersio

Effect of sodium and nitrogen on yield function of irrigated maize in Southern Portugal

Salinization and nitrate leaching are two of the leading threats to the environment of the European Mediterranean regions. Inefficient use of water and fertilizers has led to a nitrate increase in the aquifers and reduction in crop yields caused by salts. In this study, a triple emitter source irrigation system delivers water, salt (Na+), and fertilizer (N) applications to maize (Zea mays L.). The objective of the study was to evaluate the combined effect of saline water and nitrogen application on crop yields in two different textured soils of Alentejo (Portugal) and to assess if increasing salinity levels of the irrigation water can be compensated by application of nitrogen while still obtaining acceptable crop yield. Maximum yield was obtained from both soils with an application of 13 g m−2 of nitrogen. Yield response to Na+ application was different in the two studied soils and depended on the total amount of Na+ or irrigation water applied. No significant interaction was found between nitrogen and sodium, but a positive effect on maize yield was observed in the medium textured soil for amounts of Na+ less than 905 g m−2 when applied in the irrigation water

Modelling the effect of non-planarity on luminescence energy of conjugated polymers

We present theoretical investigations of structural and electronic properties of ground-state and low-lying excited singlet states in isolated chains of conjugated polymers using a self-consistent quantum molecular dynamics method. With this approach, we have determined the energy of both states as function of the twist angle between two planar segments of the same polymer chain, for polymer chains with variable length. The conjugated polymers investigated here are poly(para-phenylene vinylene) (PPV) and polydiacetylene (PDA). Our results show that the energy of the excited-state increases more than that of the ground-state, as the twist angle increases up to 90º degrees. The change in the twist angle of both polymers leads to a blueshift in luminescence transition energy, the effect being stronger in PPV when the planar segments have similar sizes. The predicted blueshift in both polymers is dependent on the chain length, the effect being more pronounced for shorter-chains.Comunidade Europeia (CE). Fundo Europeu de Desenvolvimento Regional (FEDER)Fundação para a Ciência e a Tecnologia (FCT) - Programa Operacional “Ciência , Tecnologia, Inovação” – POCTI/CTM/41574/2001, CONC-REEQ/443/2001 e SFRH/BD/11231/200