Search results for "Investigacion"
showing 10 items of 152 documents
Climate Aridity and the Geographical Shift of Olive Trees in a Mediterranean Northern Region
2021
Climate change leverages landscape transformations and exerts variable pressure on natural environments and rural systems. Earlier studies outlined how Mediterranean Europe has become a global hotspot of climate warming and land use change. The present work assumes the olive tree, a typical Mediterranean crop, as a candidate bioclimatic indicator, delineating the latent impact of climate aridity on traditional cropping systems at the northern range of the biogeographical distribution of the olive tree. Since the olive tree follows a well-defined latitude gradient with a progressive decline in both frequency and density moving toward the north, we considered Italy as an appropriate case to i…
Long-term organic farming on a citrus plantation results in soil organic carbon recovery
2019
[ES] Se ha demostrado que el manejo del suelo bajo agricultura ecológica puede aumentar el contenido de carbono orgánico en el suelo moderando el incremento de los gases de efecto invernadero, pero hasta la fecha las evaluaciones cuantitativas basadas en mediciones a largo plazo han sido escasas, especialmente bajo condiciones mediterráneas. En esta investigación se examinaron los cambios en el contenido de carbono orgánico como respuesta a la agricultura ecológica con cobertura vegetal en una plantación de cítricos en el área mediterránea, utilizando una base de datos de 21 años. El incremento de contenido de carbono orgánico en el suelo fue más evidente tras cinco años desde el cambio del…
High-to-low (Regional) fertility transitions in a peripheral european country: The contribution of exploratory time series analysis
2021
Diachronic variations in demographic rates have frequently reflected social transformations and a (more or less evident) impact of sequential economic downturns. By assessing changes over time in Total Fertility Rate (TFR) at the regional scale in Italy, our study investigates the long-term transition (1952–2019) characteristic of Mediterranean fertility, showing a continuous decline of births since the late 1970s and marked disparities between high- and low-fertility regions along the latitude gradient. Together with a rapid decline in the country TFR, the spatiotemporal evolution of regional fertility in Italy—illustrated through an exploratory time series statistical approach—outlines th…
Long-term impact of rainfed agricultural land abandonment on soil erosion in the Western Mediterranean basin
2018
[EN] Land abandonment is widespread in the Mediterranean mountains. The impact of agricultural abandonment results in a shift in ecosystem evolution due to changes in soil erosion, but little is known about long-term soil and water losses. This paper uses 11 years of measurements in two paired plots (abandoned vs control) with four subplots to determine how soil and water losses evolved after abandonment within an agricultural parcel. For two years (2004¿2005) both plots were under tillage, and after 2006 one plot was abandoned. The monitored plots measured runoff and sediment concentration after each rainfall event.
La expansión geográfica de la renta del tabaco
2007
El monopolio real del tabaco fue decretado sólo para la Corona de Castilla en 1636. Debido a su reconocida eficacia, los gobernantes españoles intentaron implantarlo allá donde fuese políticamente posible. Después de la guerra de Sucesión, fue establecido en la Corona de Aragón, ya que estos territorios perdieron entonces su régimen foral de autonomía. Como las provincias vascas y Navarra consiguieron conservar su régimen foral, el Gobierno español no pudo someter allí el régimen general del estanco tabaquero y tuvo que contentarse con negociar soluciones que no perjudicasen al estanco general. Finalmente, en el contexto de las reformas borbónicas en América, la Renta del Tabaco fue gradual…
Locura y muerte de Nadie. Leer a Benjamín Jarnés hoy en día
2010
El presente trabajo lleva a cabo un análisis de la conocida novela de Benjamín Jarnés “Locura y muerte de Nadie” (1929), una de las más logradas manifestaciones de la narrativa de vanguardia española, desde una óptica nueva, es decir una mirada actual desde las complejidades de la época contemporánea. En particular, a través del estudio del tema de la identidad, tópico del género de la novela de vanguardia, se quiere demonstrar que la sociedad de masas representada y criticada por el autor español encuentra su correspondiente en la sociedad tecnológica de hoy en día; el ‘hombre perdido’, tal como lo definiría Ramón Gómez de la Serna, a principios del siglo Veinte así como en la actualidad, …
Do conservative agriculture practices increase soil water repellency? A case study in citrus-cropped soils
2012
Water repellency is a property of soils that inhibits or delays infiltration. Long-term conservation practices as no-tillage, manure addition, application of herbicides may contribute to increase soil organic matter and, hence, soil water repellency. In this research, we have studied the effect of long-term addition of plant residues and organic manure, no-tillage and no chemical fertilization (MNT), annual addition of plant residues and no-tillage (NT), application of conventional herbicides and no-tillage (H), and conventional tillage (CT) on soil water repellency in Mediterranean calcareous citrus-cropped soils (Eastern Spain). Slight water repellency was observed in MNT soils, which may…
Greedy and K-Greedy algoritmhs for multidimensional data association
2011
[EN] The multidimensional assignment (MDA) problem is a combinatorial optimization problem arising in many applications, for instance multitarget tracking (MTT). The objective of an MDA problem of dimension $d\in\Bbb{N}$ is to match groups of $d$ objects in such a way that each measurement is associated with at most one track and each track is associated with at most one measurement from each list, optimizing a certain objective function. It is well known that the MDA problem is NP-hard for $d\geq3$. In this paper five new polynomial time heuristics to solve the MDA problem arising in MTT are presented. They are all based on the semi-greedy approach introduced in earlier research. Experimen…
Integer programming models for the pre-marshalling problem
2019
[EN] The performance of shipping companies greatly depends on reduced berthing times. The trend towards bigger ships and shorter berthing times places severe stress on container terminals, which cannot simply increase the available cranes indefinitely. Therefore, the focus is on optimizing existing resources. An effective way of speeding up the loading/unloading operations of ships at the container terminal is to use the idle time before the arrival of a ship for sorting the stored containers in advance. The pre-marshalling problem consists in rearranging the containers placed in a bay in the order in which they will be required later, looking for a sequence with the minimum number of moves…
Redesigning work in university classrooms: factors related to satisfaction in engineering and business administration students
2014
Objeto: Con este trabajo se pretende analizar cómo afectan las características del contexto del aprendizaje, es decir, cómo es el trabajo de los estudiantes en la asignatura, al potencial motivador de la asignatura y a la satisfacción de los estudiantes. Diseño/metodología/enfoque: Mediante ecuaciones estructurales (SEM) se ha analizado los datos de una muestra transversal (cursos 2008, 2009 y 2010) de 535 estudiantes de ingeniería industrial y administración de empresas, de una universidad pública española. Aportaciones y resultados: Los resultados, utilizando un instrumento validado y adaptado al mundo docente, demuestran la asociación existente entre las características del tipo de traba…