Leptin, the product of the ob gene, is a recently discovered hormone secreted by adipocytes. Serum leptin concentrations increase in correlation with the percentage of body fat, but besides that little is known about the physiological actions of leptin in humans. The aim of this study was to assess the influence of changes in circulating free-fatty acids on serum leptin levels. Increases in plasma FFA levels (p < 0.02) were obtained in a group of normal subjects following the administration of intralipid plus heparin (250 ml 10% Intralipid plus 5000 U heparin). FFA reduction was achieved through the administration of acipimox (250 mg, orally, at 0 min and at 210 min), a lipid-lowering drug devoid of side effects, to a group of normal (p < 0.02) and obese subjects (p < 0.05). An increase in circulating FFA levels in normal subjects (n = 6), following administration of a lipid-heparin infusion, failed to modify plasma leptin levels as assessed by the area under the curve (AUC; mean +/- SE 892 +/- 168 for placebo vs 896 +/- 260 following intralipid plus heparin). Similarly, whereas acipimox pretreatment induced a reduction in FFA levels compared to placebo in normal (n = 6) and obese subjects (n = 8), it also failed to modify plasma leptin levels at any time-point studied. The results indicate that short-term reduction or increase in circulating FFA are not associated to changes in plasma leptin levels.

This research makes a highly relevant contribution to the scientific analysis of the mining landscape using the example of Cartagena-La Unión (Spain). The landscape is interpreted from a twin perspective: as a type of digital content offered to visitors and as a highly valuable scenic tourism resource. The article features an extensive bibliographical review and offers different perspectives on the relationship between landscape, tourism, and smart promotion. The method used is both qualitative and quantitative due to the presentation of statistical data. It describes a purpose-designed form used for analyzing the landscape in question and a synthetic landscape assessment index, as a result of creating and using different indicators. Extensive field work and consultation with several sources provided information about the enclave, how much it appeals to visitors, and their level of satisfaction. The results achieved offer a new scientific vision of what a spectacular cultural landscape, and a point of reference for "mining heritage tourism", can represent.

Resumen tesis: Dinámica evolutiva de los usos y coberturas del suelo en la provincia de Salamanca. Análisis comparado y repercusiones en el paisaje rural de cuatro comarcas de estudio. Departamento de Geografía, Universidad Nacional de Educación a Distancia (UNED). Director: Dr. D. Carlos Javier Pardo Abad. Fecha: 27/05/2021.

Desde mediados del siglo XX el espacio agrario de Castilla y León, y de gran parte de España, viene transformando las características que durante años definieron su estructuración. La masiva movilización demográfica obligó a adaptar los territorios ante el imponente grado de despoblación y con el fin de aumentar la producción, reducir los costes y poder, de este modo, competir en un mercado globalizado. El índice de correlación ayudará a garantizar la estrecha vinculación existente entre la dinámica poblacional, las variables estructurales y el fenómeno de la concentración parcelaria, mecanismo que se convertirá en el verdadero instrumento de modernización de la estructura agraria, centrado en eliminar las propiedades negativas que hasta la década de los 60 dominaban el espacio agrario castellano y leonés, si bien, este estará condicionado en todo momento por los componentes físicos de la altitud, la pendiente y el material geológico presentes en el territorio. Abstract Since the mid-twentieth century the agrarian space of Castilla y León, and much of Spain, has been transforming the characteristics that for years defined its structuring. The massive demographic mobilization forced to adapt the territories against the imposing degree of depopulation, in order to increase production, reduce costs and be able to compete, in this way, in a globalized market. The correlation index will help guarantee the close link between population dynamics, structural variables and the phenomenon of land consolidation, a mechanism that will become the real instrument for the modernization of the agrarian structure, focused on eliminating the negative properties that dominated the castellano y leonés space until the 60s, although this will be conditioned at all times by the physical components of altitude, slope and geological material present in the territory.