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[SPA] Se utiliza un modelo hidrológico distribuido para evaluar cómo diferentes métodos influyen en la estimación de la evapotranspiración (ETc) y el balance de agua a escala de cuenca. La zona de estudio se ubica en la cuenca alta del Segura (~ 2.500 km2) en el Sureste español, zona caracterizada por una elevada heterogeneidad de condiciones del terreno y usos del suelo. El modelo hidrológico SPHY fue desarrollado y calibrado para un período de simulación de 15 años. Se emplearon cinco métodos para parametrizar el coeficiente de cultivo y se compararon los patrones espaciales y las dinámicas temporales simuladas para la evapotranspiración, la humedad del suelo y los caudales. Tres de los cinco métodos utilizan información de satélite, otro los valores del coeficiente de cultivo establecidos por FAO, y el último asume un valor constante para toda la cuenca y periodo de simulación. El análisis muestra que la generación de caudales apenas se ve afectada por la selección del método de parametrización, aunque sí es importante a la hora de calcular la evapotranspiración real, especialmente durante épocas húmedas y para los valores tabulados de FAO. [ENG] A distributed hydrologic model is used to evaluate how different methods to estimate evapotranspiration (ETc) influence the water balance and hydrologic response of basins. The study site, the upper Segura basin (~2500 km2) in Spain, is characterized by a wide range of terrain, soil, and ecosystem conditions. Input and calibration data for the hydrological model SPHY are obtained from best available data sources. The model was setup for a period of 15 year. Five crop coefficient parameterization methods are compared to explore the impact of spatial and temporal variations in these input datasets on actual evapotranspiration, streamflow and soil moisture. Methods include three that are based on remote sensing information; one based on FAO literature, and another that takes the crop coefficient equal to unity for the entire basin. The analysis shows that basin-level streamflow is hardly influenced by the choice in parameterization, but actual evapotranspiration and soil moisture are quite different, especially in the wet season and for the FAO-based method.

With the purpose of analysing the type (labile or stable) and quantity of organic carbon (OC) mobilized by different erosive processes identified at the slope-bed connection, the erosion deposits of gullies, sheet erosion, bank erosion and tillage erosion were studied in a small catchment (10 ha) and compared to the characteristics of the catchment soils. Selectivity upon soil detachment and transport was associated to different OC content and types in the erosion deposits. Enrichment ratios of organic carbon sediment/soil were low (~0,40 ± 0,26), even though a slight enrichment was described for fine particles (positively correlated to CO). These results were attributed to mineralization processes prevailing over OC burial in a very active channel where depositional sites are scarce., Con el fin de caracterizar la cantidad y tipo (lábil o recalcitrante) de carbono orgánico (CO) movilizado por distintos procesos erosivos identificados en las conexiones ladera-cauce, se estudiaron las características de los depósitos de erosión concentrada en cárcavas, erosión hídrica laminar, erosión lateral-gravitacional y erosión por laboreo en el contacto ladera-cauce de una cuenca de pequeño tamaño (10 ha) y se relacionaron con las características de los suelos-fuentes originales de donde procedían. La selectividad en el arranque y transporte de suelo de los distintos procesos se pudo asociar a diferentes contenidos y tipos de CO en los depósitos. Las razones de enriquecimiento de carbono orgánico sedimento/suelo fueron bajas (~0,40 ± 0,26), a pesar de haber un ligero enriquecimiento en partículas finas (correlacionadas positivamente con el CO) en los depósitos. Todo ello se atribuyó a los efectos de la mineralización en un cauce muy activo con pocas zonas de deposición y abundantes procesos de erosión no selectiva.

Item does not contain fulltext Little is known of the biochemical processes of cognitive decline during 'healthy' aging. Biological markers in body fluids, such as blood, could provide insight in those processes. In the present studies serum concentrations of different markers have been correlated to cognitive functioning of cognitively healthy aging individuals over a period of six years (mean age 57 years, SD 11, n = 93). Markers were related to mechanisms known to be involved in Alzheimer's disease, including inflammation, cholesterol homeostasis and homocysteine homeostasis. Domains of cognitive function addressed were cognitive speed (Letter-Digit Coding test), attention and information processing (Stroop test), and memory (Word Learning test: Total Words and Delayed Recall). Baseline concentrations of haptoglobine, homocysteine, lathosterol and lanosterol were negatively correlated with cognitive functioning on the Stroop test over the whole follow-up period of six years. Concentrations of all markers, i.e. haptoglobine, C-reactive protein, homocysteine, lathosterol and lanosterol, were also negatively correlated with functioning on the Word Learning test (Delayed Recall and for some markers also with the Total Words) over the whole six-years follow-up period. In conclusion, concentrations of serum markers related to inflammation, homocysteine and cholesterol homeostasis are not only associated with Alzheimer's disease, but also with cognitive functioning in the cognitively healthy aging population.

Studies with Escherichia coli-induced heat-stable enterotoxin (STa), an activator of intestinal particulate guanylate cyclase, have established an independent role for cyclic guanosine monophosphate (cGMP) as an intracellular mediator of intestinal salt and water secretion. The present study addressed whether atriopeptins (APs), known activators of particulate guanylate cyclase in other tissues, function as physiological agonists for cGMP-linked Cl- secretion in intestine. APs, in contrast to STa, caused no or only minor changes in cGMP levels in freshly isolated rat intestinal villus and crypt cells and in cultured human colon carcinoma cell lines (HT29glc-, CaCo-2, and T84). Conversely, APs, but not STa, induced a large increase in intracellular cGMP levels in the undifferentiated small intestinal cell lines IEC-6, IEC-18, and INT407. Addition of AP II (atrial natriuretic peptide fragment 5-27) to stripped mucosa of rat proximal colon in Ussing chambers caused a transient increase in the transepithelial potential difference (PD), which most likely represents an increase in Cl- secretion. In contrast, a sustained increase in PD was observed in response to STa or 8Br-cGMP. The AP II-provoked increase in PD was blocked by the neurotoxin tetrodotoxin. Immunohistochemical detection of cGMP in this tissue provided evidence for a different localization pattern of cells responding with an increase in cGMP levels to STa (colonocytes and goblet cells) or AP (specific cells in the submucosa) in rat proximal colon. This indicates that APs, unlike STa, do not directly stimulate the colonic epithelial cells but possibly provoke Cl- secretion by release of a neurotransmitter in the submucosa.

Fluorescence spectroscopic analysis based upon the difference in fluorescent behaviour of several phenol, catechol and resorcinol derivatives in 0·2 M phosphate and water, at different pH values ranging from 7·4 to 1·0, produced evidence for the existence of complexes between phosphate anions and these compounds. This complex formation was also found with acetate, citrate and glutamate but not with sulphate and borate. A comparison of different ligand structures revealed that the complex formation observed with unsubstituted phenol, catechol or resorcinol was not influenced by ethyl substitution; however, ethylamine or ethanolamine substitution favoured the formation of the complex. The findings indicate the formation of 1:1 intermolecular complexes between mono- and dihydroxyphenethylamines and several anionic species with participation of two hydrogen bonds. The predictions of a theoretical model describing this interaction are confirmed by the experimental data. Association constants of isoprenaline with phosphate and glutamate were found to be 5·1 and 26·6 litres mol−1 respectively; for the complexes of m-tyramine and terbutaline with phosphate, association constants of 15·3 and 6·9 litres mol−1 respectively, were obtained.