Anforetas y botijuelas halladas en Guipúzcoa.

Se estudian dos anforetas y dos botijuelas procedentes de Hondarribia y Bergara, siendo las primeras piezas de esta índole que se publican en Guipúzcoa. En espera de nuevos hallazgos que lo confirmen se puede adelantar que son vasijas de larga pervivencia, cuyo uso, muy discutido, va desde la iluminación hasta el transporte de mercancías con una cronología muy amplia, del siglo XV a XVIII

INVESTIGATION OF CHEMOMETRICS METHODS FOR CHARACTERISING DRIFT PHENOMENA IN iCK-AES

The objective of this study was to fully characterise drift phenomena in inductively coupled plasma atomic emission spectroscopy (ICP-AES) in order to develop novel correction procedures to aid routine analysis. Long-term drift of the analytical signal continues to be a potential disadvantage when using ICP-AES and often necessitates regular recalibration. The long-term stability of three commercially available Instruments was studied using In each case a range of analyte and intrinsic plasma emission lines. Long-term fluctuations were observed which generated drift bias of up to 20% on the initial values. The drift pafterns were characterised and found to be qualitatively reproducible. In most cases, similar long-term fluctuations were observed independent of the analyte or nature of the emission line. In addition, high inter-element correlation was observed on the long-term fluctuations even when sequential acquisition was employed. In order to study the fundamental causes of drift, the effect of two key instrumental parameters, i.e. the RF power and the nebutiser gas flow rate were studied with respect to the stability of the signal. Different drift patterns were found depending on the working conditions. Classical statistical methods and a multi-way approach. PARAFAC. were then employed to describe the system. The use of intemal standards to correct for drift has also been investigated, but found to be of benefit only under certain defined conditions (i.e. robust conditions, high RF power and low nebuliserflow rate). At soft conditions, low RF power and medium to high nebuliser flow rate, the system Is very unstable and intemal standardisation is not fully effective as a correction method. For such conditions, a novel correction procedure has been developed, which employs the drift pattem of one intrinsic plasma line (i.e. an argon line) and a correction factor which is specific for each emission line. The drift values were reduced from around 20% before correction to better than ±2% following the described protocol. Finally, the effects of chemical matrices on the long-term stability of the emission signals have been evaluated. Three synthetic matrices were prepared simulating nitric, soil and water matrices. The stability of the instrument when working wrth these matrices at both robust and soft conditions was found to be poor, especially when the solution was matched with the soil matrix. The use of more robust conditions did not improve the long-temi stability of the emission signals. The outcome of this study proved to be a better understanding of drift phenomena and a novel method for drift correction.BRITISH GEOLOGICAL SURVE

Sector bancario y coyuntura económica.

Continuando con la línea de investigación de la política coyuntural de la empresa, se busca realizar un estudio del sector bancario colombiano. El punto de partida es que existen ciertos elementos del sector bancario que lo diferencian de los demás sectores de la economía: su dinámica está determinada por el comportamiento de los demás agentes económicos (empresas, gobierno, sector externo, familias), la política monetaria y crediticia, la competencia de otros intermediarios y la asimetría de la información. Esto significa que la actividad bancaria es quizás la más expuesta a las fluctuaciones coyunturales del sistema económico, dado que alteraciones significativas e imprevistas en el comportamiento de los agentes se transmitirán inmediatamente al desempeño bancario. Además de profundizar en el estudio de la política coyuntural de la empresa se presenta una descripción de la evolución del sector bancario en la década de los noventa y se realizan tres ejercicios empíricos: una aplicación del Modelo CAMEL para el sector bancario y un análisis de la sensibilidad coyuntural de los bancos privados colombianos para el periodo 1990 - 2000, por medio de los modelos Logit y de Panel Data. Los resultados indican que, en efecto, la influencia de las variables y políticas macroeconómicas es alta sobre los balances de las entidades bancarias

Oxidation-assisted alkaline precipitation : the effect of H2O2 on the size of CuO and FeOOH nanoparticles

H2O2 was demonstrated to narrow the size distribution and decrease the size of CuO and hydrous FeOOH (2-line ferrihydrite) nanoparticles under conditions of high supersaturation. We introduce oxidation-assisted alkaline precipitation (Ox-AP) and compare it to traditional alkaline precipitation (AP). While for AP, a metal salt solution (e.g., CuCl2) is mixed with an alkali (e.g., NaOH), for Ox-AP, the more reduced form of that metal salt solution (e.g., CuCl) is simultaneously mixed with that alkali and an oxidant (e.g., H2O2). The resulting precipitates were characterized with SEM, XRD, DLS and single particle ICP-MS and shown to be nanoparticles (NPs). Ox-AP CuO NPs were up to 3 times smaller than AP NPs. Ox-AP FeOOH NPs were up to 22.5% smaller than AP NPs. We discuss and propose a possible mechanism of Ox-AP through careful consideration of the known reaction chemistry of iron and copper. We propose that an increased monomer formation rate enhances the nucleation rate, which ultimately results in smaller particles with a more narrow distribution. The more distinct effect of Ox-AP on copper, was attributed to the fast formation of the stable CuO monomer, compared to AP, where the Cu(OH)(2) and/or Cu-2(OH)(3)Cl monomers are more likely formed. Although, the exact mechanism of Ox-AP needs experimental confirmation, our results nicely demonstrate the potential of using Ox-AP to produce smaller NPs with a more narrow distribution in comparison to using AP

Las grafías de los planes de integración de la infraestructura regional suramericana (IIRSA)

El Plan de Integración de la Infraestructura Regional Sudamericana (IIRSA) surge en una reunión de presidentes realizada en Brasilia el 31 de agosto y 1º de setiembre del año 2000, en la que los mandatarios de la región acuerdan realizar acciones conjuntas para im‑ pulsar un proceso de integración física que incluye la creación de una importante red de las infraestructuras de transporte, energía y telecomunicaciones en un periodo de un decenio (2000–2010) y realizar proyecciones a futuro para 380 millones de personas. La Iniciativa comprende 514 proyectos de infraestructura de integración con una inversión estimada en 69 mil millones de dólares

Novel and simple test plating for screening relative transfructosylation activity of fungi

Fructooligosaccharides (FOS) have received particular attention recently because of their excellent biological and functional properties, namely, as prebiotic compounds that promote the growth of intestinal microflora. They are also low calorie non-carcinogenic sweeteners with numerous suggested health benefits. These include immune system activation, resistance to infections, synthesis of Bcomplex vitamins, calcium absorption. They can be used as a treatment for breast cancer, diarrhoea, and constipation. Although FOS are present in trace amounts in fruits, vegetables and honey as natural products, its mass production is limited by seasonal restrictions and the inherent inefficiencies of these systems. Hence, microbial FOS production by fungi in bioreactors is more realistic. Several microorganisms are reported to have transfructosylation activity due to fructosyltransferase (EC 2.4.1.9) and/or fructofuranosidase (EC 3.2.1.26) activities. However, the search for other fungi with higher transfructosylation activity is still a challenge. So, a presumptive and indirect colorimetric plate assay for the evaluation of transfructosylation activity in fungi was developed by the simultaneous determination in the same plate of glucose and fructose released from sucrose. The method entailed the coupling of two dye systems, namely the glucose oxidase-peroxidase coupled reaction using phenol and 4-aminoantipyrine for determination of glucose; and the fructose dehydrogenase oxidation in the presence of a tetrazolium salt for determination of fructose. In order to have a standard assay, the fungi were grown on Czapek Dox (CD) agar. 1 disc of mycelium (8 mm diameter) was cut from the edge of each colony and then put in contact with CD agar plates. After incubation at 25 ºC for 72 h each assay plate was overlaid with soft agar containing the reagents. The presence of enzymes with transfructosylation activity was identified by the formation of pink (presence of glucose) and blue (presence of fructose) halos around the discs. In conclusion, the results showed that the method is suitable for screening a large number of fungi due to its simplicity, reproducibility and rapidity.Agência de Inovação (AdI) - project BIOLIFE ref. PRIME 03/347