Doctoral education in the EEES context. A competence base-training

Este artículo analiza algunos aspectos relacionados con la formación de doctores en el contexto del EEES. La reforma de la formación de doctores ha experimentado un cambio muy sustancial a lo largo de las últimas décadas. Se destaca la importancia de la formación doctoral para el ejercicio profesional dentro y fuera de las instituciones universitarias. El nuevo concepto de formación se basa en competencias y no sólo en la realización de la tesis doctoral. Son numerosas las propuestas sobre las competencias en las que deben formarse los doctorandos, centrándose en las transferibles. En nuestro contexto, el proyecto de Real Decreto que regula las enseñanzas oficiales de Doctorado completará el cuadro de cualificaciones del sistema universitario.This paper analyses some of the aspects related to doctoral training within the ESHE context. In the last two decades there have been dramatic changes in doctoral training and particular importance is placed on this kind of training in the workplace both at University and elsewhere. The new concept of training is based on competences and not merely on the writing of a doctoral thesis. Prospective doctors are expected to develop a number of competences, of which transferable competences are the most outstanding ones. In our Spanish context, the final qualification structure of university studies will be completed after the inclusion of the Royal Decree project that regulates official teaching of PhD degrees

El cielo único europeo, implicaciones para la defensa

Su autor nos presenta un tema de gran actualidad y que posiblemente deberá ser tratado durante la Presidencia española de la Unión (primer semestre de 2002), a fin de conseguir que el llamado «Cielo Único Europeo» sea una realidad en diciembre de 2004.<br /> El contenido del artículo es interesante desde el punto de vista profesional militar para poder vislumbrar los problemas con que se va a enfrentar en el futuro el Ejército del Aire, así como para el público en general, pues, en forma amena, se exponen las medidas y formas de llevarlas a cabo si se quiere agilizar y flexibilizar el transporte aéreo en Europa, sin que ello repercuta de forma negativa sobre las necesidades militares

El cielo único europeo, implicaciones para la defensa

Su autor nos presenta un tema de gran actualidad y que posiblemente deberá ser tratado durante la Presidencia española de la Unión (primer semestre de 2002), a fin de conseguir que el llamado «Cielo Único Europeo» sea una realidad en diciembre de 2004. El contenido del artículo es interesante desde el punto de vista profesional militar para poder vislumbrar los problemas con que se va a enfrentar en el futuro el Ejército del Aire, así como para el público en general, pues, en forma amena, se exponen las medidas y formas de llevarlas a cabo si se quiere agilizar y flexibilizar el transporte aéreo en Europa, sin que ello repercuta de forma negativa sobre las necesidades militares

Conversion of Exhausted Sugar Beet Pulp into Fermentable Sugars from a Biorefinery Approach

In this study, the production of a hydrolysate rich in fermentable sugars, which could be used as a generic microbial culture medium, was carried out by using exhausted sugar beet pulp pellets (ESBPPs) as raw material. For this purpose, the hydrolysis was performed through the direct addition of the fermented ESBPPs obtained by fungal solid-state fermentation (SSF) as an enzyme source. By directly using this fermented solid, the stages for enzyme extraction and purification were avoided. The effects of temperature, fermented to fresh solid ratio, supplementation of fermented ESBPP with commercial cellulase, and the use of high-solid fed-batch enzymatic hydrolysis were studied to obtain the maximum reducing sugar (RS) concentration and productivity. The highest RS concentration and productivity, 127.3 g.L-1 and 24.3 g.L-1.h(-1) respectively, were obtained at 50 degrees C and with an initial supplementation of 2.17 U of Celluclast (R) per gram of dried solid in fed-batch mode. This process was carried out with a liquid to solid ratio of 4.3 mL.g(-1) solid, by adding 15 g of fermented solid and 13.75 g of fresh solid at the beginning of the hydrolysis, and then the same amount of fresh solid 3 times every 2.5 h. By this procedure, ESBPP can be used to produce a generic microbial feedstock, which contains a high concentration of monosaccharides

Metastable phenomena on calcite {1014} surfaces growing from Sr2+–Ca2+–CO3 2- aqueous solutions

In situ atomic force microscopy (AFM) experiments, scanning electron microscopy (SEM) imaging and composition analysis, and X-ray diffraction have provided information about the growth, dissolution and transformation processes promoted by Sr2 + –Ca2 + –CO3 2 aqueous solutions in contact with calcite {101¯4} surfaces. Experiments have shown a wide variety of surface phenomena, such as the influence of the Sr-bearing newly-formed surface on the subsequent growth (template effect), the growth and subsequent dissolution of surfaces and the nucleation of secondary three-dimensional nuclei on calcite surfaces. These phenomena reveal the metastability of the crystallisation system and are a consequence of the interplay between thermodynamics (the relative stability of the two calcite and aragonite structure solid solutions that can be formed), supersaturation of the aqueous solution with respect to the two possible solid solutions, and the crystallographic control of the surfaces on cation incorporation

Growth of β-LiNaSO4 and Li2SO4 . H20: epitaxy and intergrowth phenomena

Isothermal crystallization in the system Na2SO4-Li2SO4-H20 was carried out at 50°C by "salting out" in a tetrametoxysilane (TMS) gel medium. Under these conditions the solid phases that can crystallize are Na2SO4, Li2SO4 . H20 and β-LiNaSO4, depending on the initial composition of the gel interstitial solution. When the initial [Na2SO4]/[Li2SO4] molar ratio in the interstitial solution is smaller than 1, first β-LiNaSO4 crystallizes and, subsequently, Li2SO4 • H20. The nucleation of Li2SO4 • H20 is always heterogeneous and occurs epitaxially on the surface of β-LiNaSO4 crystals. Occasionally, successive heterogenous nucleation events promote the development of intergrowth phenomena. In this paper a detailed study of both epitactic growth and crystal morphology is worked out. Finally, the observed epitaxial relationships are interpreted on the ground of structural considerations

Valorisation of fungal hydrolysates of exhausted sugar beet pulp for lactic acid production

BACKGROUND Exhausted sugar beet pulp pellets (ESBPP) were used as raw material for lactic acid (LA) fermentation. The enzymatic hydrolysis of ESBPP was performed with the solid obtained after the fungal solid-state fermentation of ESBPP as a source of hydrolytic enzymes. Subsequently, a medium rich in glucose and arabinose was obtained, which was used to produce LA by fermentation. For LA production, two Lactobacillus strains were assayed and the effects of the supplementation of the hydrolysate with a nitrogen source and the mode of pH regulation of the fermentation were investigated. Moreover, a kinetic model for LA fermentation by Lactobacillus plantarum of ESBPP hydrolysates was developed. RESULTS L. plantarum produced a LA concentration 34% higher than that produced by L. casei. The highest LA concentration (30 g L−1) was obtained with L. plantarum when the hydrolysate was supplemented with 5 g L−1 yeast extract and the pH was controlled with CaCO3. The concentration of acetic acid differed depending on the concentration of CaCO3 added, producing its maximum value with 27 g L−1 CaCO3. The proposed kinetic model was able to predict the evolution of substrates and products depending on the variation of the pH in the hydrolysate, according to the amount of CaCO3 added. CONCLUSIONS ESBPP can be valorised to produce LA. A pure LA stream or a mixture of LA and acetic acid, depending on the pH control method of the fermentation, can be produced. Thus, this control is of great interest depending on the destination of the effluent

Modelling and Optimization of Simultaneous Saccharification and Fermentation of Agro-Food Residues

In terms of productivity, bioethanol production from agri-food residues can be improved by carrying out simultaneously the two involved stages (enzyme hydrolysis and alcohol fermentation). This is because the shorter the process duration, the higher the overall productivity achieved. In this work, two kinetic models previously developed by the authors have been combined to obtain a general kinetic model for the simultaneous saccharification and fermentation of lignocellulosic materials. The validity of the combined model has been tested using three different agri-food residues: wheat straw, rice husks and exhausted sugar beet pulp. Later, the model has been used to calculate productivity under many different conditions and to optimize the industrial process. After this study, it is concluded that some important operating variables, such as the enzyme dose and the inoculum strength, must be well coupled to obtain the maximal yield from residues. Thus, the overall productivity obtained in the laboratory experiments was under 5 mg of ethanol per gram of solid waste and per hour. However, the simulations in the optimal operating conditions predict productivities up to double that

The effect of CO2-3 on the growth of barite {001} and {210} surfaces: An AFM study

The growth of barite {001} and {210} faces from aqueous solutions moderately supersaturated with respect to barite (βbarite ≈ 12 for experiments on {001} surfaces and βbarite ≈ 7 for experiments on {210} surfaces) and bearing different concentrations of carbonate has been studied in situ using an atomic force microscope (AFM). Nanoscopic observations show that, above a certain carbonate concentration threshold in the aqueous solution, the advancement of monolayers (~3.5Å in height) on barite {001} and {210} surfaces is strongly inhibited. However, inhibition never affects the growth of the first monolayer, whose growth rate increases in the presence of carbonate. In contrast, the second monolayer growth rate decreases as the concentration of carbonate in the solution increases. For high carbonate concentrations in the solution, growth stops after the formation of the first monolayer. While on barite {001} faces, the formation of a second monolayer does not occur for carbonate concentrations higher than 0.2 mM, on barite {210} faces the complete inhibition of the second monolayer is observed for carbonate concentrations higher than 0.05 mM. Once growth on {001} or {210} faces is completely inhibited, i.e. such surfaces are in the ‘‘dead zone’’, growth can be recovered by increasing supersaturation. In order to study the recovery behaviour of barite {001} and {210} faces from the ‘‘dead zone’’, an additional series of AFM experiments have been conducted. In these experiments, carbonate-free aqueous solutions with increasing supersaturations with respect to barite were passed over {001} and {210} surfaces previously ‘‘poisoned’’ with carbonate. Our experimental results show that the recovery of growth on barite {001} faces requires an important increase of the solution supersaturation. In contrast, the recovery of barite {210} surface growth does not require any supersaturation increase, but spontaneously occurs in a few minutes. Our observations of inhibition and growth recovery on barite surfaces at a nano-scale are discussed and compared with the descriptions given by the classical crystal growth inhibition models