Publicacions de projectes de recerca del Plan Nacional
Permanent URI for this collection
Publicacions resultants de projectes de recerca del Plan Nacional.
- ItemOpen AccessBuscando límites a la urbanización dispersa: metodología para la delimitación de áreas urbanas en las ciudades medias españolas(Instituto Universitario de Urbanística, Universidad de Valladolid, 2023-05-16) Andrés López, Gonzalo; Bellet, Carme; Cebrián Abellán, FranciscoSe propone una metodología para la delimitación de las áreas urbanas articuladas por ciudades medias en España. Con la referencia temporal 2000-2020, se trabaja sobre un conjunto de treinta y cuatro ciudades medias interiores. El criterio de partida es el de accesibilidad, tomando la referencia de la isócrona de veinte minutos. Sobre el análisis de seis indicadores –tasa de variación de suelo urbanizado, de vivienda, y de población, índice de juventud, de población activa agraria y de población de servicios– se genera el Índice de Transformación Urbana (ITU), apoyado en el uso de técnicas multicriterio y de cartografía analítica. Se establecen tipologías de áreas urbanas según la dinámica de transformación observada (alta, media y baja) y, en cada área, se identifica el alcance, intensidad y gradación de los procesos de dispersión urbana.
- ItemOpen AccessAwned versus awnless wheat spikes: does it matter?(Elsevier, 2023) Sanchez-Bragado, Rut; Molero, Gemma; Araus Ortega, José Luis; Slafer, Gustavo A.Awnless and awned wheat is found across the globe. Archeological and historical records show that the wheat spike was predominantly awned across the many millennia following domestication. Thus, ancient farmers did not select against awns at least until the last millennium. Here, we describe the evolution and domestication of wheat awns, quantifying their role in spike photosynthesis and yield under contrasting environments. Awns increase grain weight directly (increasing the size of all grains) or indirectly (increasing the failure of distal grains), but not as a consequence of additional spike photosynthesis. However, a trade-off is produced through decreasing grain number. Thus, favorable effects of awns on yield are not consistently found across environments.
- ItemOpen AccessFrom Pyrenees to Andes: The relationship between transhumant livestock and vultures(Elsevier, 2023) Arrondo, Eneko; Guido, Jorgelina; Oliva-Vidal, Pilar; Margalida, Antoni; Lambertucci, Sergio A.; Donázar, José Antonio; Cortés-Avizanda, Ainara; Anadón, José DanielTranshumance is the traditional livestock practice consisting in the seasonal movement of herds between winter and summer pastures. Transhumance have important effects on the ecosystem functions from local to regional scales. Here, we 1) explored the relationship of vultures to transhumant herds, and 2) tested whether there is a shift on the use of space by vultures due to the decline of transhumance. For that, we first assessed whether vultures follow transhumant herds in two mountain areas with transhumant tradition, Pyrenees (Spain) and Andes (Argentina). Second, we compared both systems to determine whether the impact of transhumance on the use of space of vultures is greater in the area where transhumance is still relevant (Andes) than where this activity is in decline (Pyrenees). For this purpose, we analyzed the use of the summer pastures made by 50 griffon vultures (Gyps fulvus) and 18 Andean condors (Vultur gryphus), as assessed by GPS tracking. Our findings showed that both species respond to transhumance by making greater use of summer pastures when herds are present. A higher proportion of condors made use of summer pastures than griffons, and condors individually made a more intense use of it than griffons. Differences could be explained by the fact that transhumance in the Andes is still important while in the Pyrenees is declining and the amount of carrion provided is lower. Given that the abandonment of traditional activities is a phenomenon underway, it is urgent to evaluate the effects it will have on biodiversity conservation.
- ItemOpen AccessOn mixed radial Moore graphs of diameter 3(Elsevier, 2023-05-10) Ceresuela, Jesús M.; López Lorenzo, Ignacio; Chemisana Villegas, DanielRadial Moore graphs and digraphs are extremal graphs related to the Moore ones where the distance-preserving spanning tree is preserved for some vertices. This leads to classify them according to their proximity to being a Moore graph or digraph. In this paper we deal with mixed radial Moore graphs, where the mixed setting allows edges and arcs as different elements. An exhaustive computer search shows the top ranked graphs for an specific set of parameters. Moreover, we study the problem of their existence by providing two infinite families for different values of the degrees and diameter 3. One of these families turns out to be optimal.
- ItemOpen AccessLooking behind occlusions: A study on amodal segmentation for robust on-tree apple fruit size estimation(Elsevier, 2023) Gené Mola, Jordi; Ferrer Ferrer , Mar; Gregorio López, Eduard; Blok, Pieter M.; Hemming, Jochen; Morros Rubió, Josep Ramon; Rosell Polo, Joan Ramon; Vilaplana Besler, Verónica; Ruiz Hidalgo, JavierThe detection and sizing of fruits with computer vision methods is of interest because it provides relevant information to improve the management of orchard farming. However, the presence of partially occluded fruits limits the performance of existing methods, making reliable fruit sizing a challenging task. While previous fruit segmentation works limit segmentation to the visible region of fruits (known as modal segmentation), in this work we propose an amodal segmentation algorithm to predict the complete shape, which includes its visible and occluded regions. To do so, an end-to-end convolutional neural network (CNN) for sim ultaneous modal and amodal instance segmentation was implemented. The predicted amodal masks were used to estimate the fruit diameters in pixels. Modal masks were used to identify the visible region and measure the distance between the apples and the camera using the depth image. Finally, the fruit diameters in millimetres (mm) were computed by applying the pinhole camera model. The method was developed with a Fuji apple dataset consisting of 3925 RGB-D images acquired at different growth stages with a total of 15,335 annotated apples, and was subsequently tested in a case study to measure the diameter of Elstar apples at different growth stages. Fruit detection results showed an F1-score of 0.86 and the fruit diameter results reported a mean absolute error (MAE) of 4.5 mm and R2 = 0.80 irrespective of fruit visibility. Besides the diameter estimation, modal and amodal masks were used to automatically determine the percentage of visibility of measured apples. This feature was used as a confidence value, improving the diameter estimation to MAE = 2.93 mm and R2 = 0.91 when limiting the size estimation to fruits detected with a visibility higher than 60%. The main advantages of the present methodology are its robustness for measuring partially occluded fruits and the capability to determine the visibility percentage. The main limitation is that depth images were generated by means of photogrammetry methods, which limits the efficiency of data acquisition. To overcome this limitation, future works should consider the use of commercial RGB-D sensors. The code and the dataset used to evaluate the method have been made publicly available at https://github.com/GRAP-UdL-AT/Amodal_Fruit_Sizing.