- ItemOpen AccessMobile terrestrial laser scanner vs. UAV photogrammetry to estimate woody crop canopy parameters - Part 2: Comparison for different crops and training systems(Elsevier, 2023-07-26) Torres-Sánchez, Jorge; Escolà i Agustí, Alexandre; de Castro, Ana I.; López-Granados, Francisca; Rosell Polo, Joan Ramon; Sebé Feixas, Francesc; Jiménez-Brenes, Francisco M.; Sanz Cortiella, Ricardo; Gregorio López, Eduard; Peña, José M.The measurement of geometric canopy parameters in woody crops is an important task in Precision Agriculture because of their correlation with crop condition and productivity. In recent years, several technological approaches have been developed as an alternative to manual measurements, which are time- and labour-consuming. Two of the most commonly used 3D canopy characterization technologies are mobile terrestrial laser scanning (MTLS) based on light detection and ranging (LiDAR) sensors, and digital aerial photogrammetry (DAP) using imagery from uncrewed aerial vehicles (UAVs). Although both are state-of-the-art and have been fully tested and validated, a complete comparison between their geometric canopy parameter estimations in different woody crops and training systems has not been carried out. For this reason, a set of geometric parameters (canopy height, projected area, and volume) of a vineyard, an intensive peach orchard, and an intensive pear orchard were measured using UAV-DAP and MTLS-LiDAR. A comparison between both kinds of measurements was performed, accounting for the length of the sections in which the crop hedgerows were divided to extract the geometric parameters. Measurements from the UAV and the MTLS were highly correlated (R2 from 0.82 to 0.94) when considering the data from the three crops together, and the correlations were higher when analysing longer row sections. The canopy geometric parameters estimated using the MTLS-LiDAR always had higher values than those from the UAV-DAP. The results presented in this work provide useful data for a more informed selection of technological approaches for 3D crop characterization in Precision Fruticulture and high-throughput phenotyping.
- ItemOpen AccessMobile terrestrial laser scanner vs. UAV photogrammetry to estimate woody crop canopy parameters - Part 1: Methodology and comparison in vineyards(Elsevier, 2023-08-01) Escolà i Agustí, Alexandre; Peña, José M.; López-Granados, Francisca; Rosell Polo, Joan Ramon; de Castro, Ana I.; Gregorio López, Eduard; Jiménez-Brenes, Francisco M.; Sanz Cortiella, Ricardo; Sebé Feixas, Francesc; Llorens Calveras, Jordi; Torres-Sánchez, JorgeCharacterizing crop canopies is especially important in the management of woody crops. In this article, two systems were compared to characterise a 50 m long vineyard row section. One of the systems was a mobile terrestrial laser scanner based on a light detection and ranging (LiDAR) sensor (MTLS-LiDAR). The other was an uncrewed aerial vehicle (UAV) based system using digital aerial photogrammetry (UAV-DAP). The resulting 3D point clouds were assessed qualitatively and quantitatively. Canopy heights, widths and volumes were obtained in 0.1 m long sections along the studied row. All the parameters derived from the two systems presented statistically significant differences. The coefficients of determination between systems were 0.619 for canopy maximum heights above ground level (agl), 0.686 for 90th percentile (P90) heights agl, and 0.283 and 0.274 for maximum and P90 vegetated heights, respectively. Coefficients of determination between averaged maximum canopy width and P90 canopy width were 0.328 and 0.317, respectively. Coefficients of determination between cross-sectional areas determined from maximum widths, P90 widths and from the occupancy grid method were 0.423, 0.409 and 0.334, respectively. Total canopy volume for the entire row obtained from the three cross section estimation methods differed between 19 m3 and 25 m3. The reasons found were that the MTLS-LiDAR-derived point cloud captured the canopy top and side variability but could be affected by occlusions, mixed pixels and tall grass-like weeds present in the surveyed area. For its part, the UAV-DAP-derived point cloud tended to miss top and side shoots and somewhat smoothed canopy variability. As neither of the systems is optimal, a balance needs to be found according to the specific requirements of the survey. For this purpose, a list of pros and cons is presented to support the selection of one of the two systems for canopy monitoring. The MTLS-LiDAR system should be chosen when high detail is required but small areas are to be scanned. Alternatively, the UAV-DAP system should be chosen when large areas are to be monitored and when canopy detail is not so important. Further results are presented in Part 2 for a larger area and including pear and peach orchards with different training systems. Future research is to be conducted on how the compared systems affect variability detection and support variable-rate prescriptions.
- ItemOpen AccessVocabulario emocional de alumnos de educación primaria(Universidad CES, 2023) Ricart Aranda, Maria; Coronel, Mónica; Solé Llussà, Anna; Ros Morente, Agnès; Bisquerra Alzina, RafaelEl dominio del vocabulario emocional contribuye a construir nuestro saber acerca del mundo y favorece la construcción de la realidad emocional que se percibe a nivel individual. Este estudio se centró en identificar las diferencias en el vocabulario emocional en función de la edad y el género de alumnos de educación primaria. La muestra total fue de 551 participantes, estudiantes de educación primaria de cuatro centros de la región de Lleida (España), cuya edad oscilaba entre 6 y 12 años. Se realizó un estudio de diseño transversal y de enfoque descriptivo-interpretativo, y se aplicó un instrumento desarrollado ad hoc con tiempo limitado para su ejecución. Los resultados demostraron el incremento del vocabulario emocional a medida que aumenta la edad, llegando a duplicar su volumen inicial, y el aumento del repertorio de palabras que aluden a emociones negativas y ambiguas a medida que aumenta la edad. Además, se detectaron diferencias en el tipo y número de palabras del vocabulario emocional según el género de los participantes, de manera que las niñas presentaron mayor número de palabras asociadas a emociones positivas y negativas, y los niños a negativas.
- ItemOpen AccessBack accumulation of diffusive gradients in thin-films devices with a stack of resin discs to assess availability of metal cations to biota in natural waters(American Chemical Society, 2023) Sans Duñó, Jordi; Cecilia Averós, Joan; Galceran i Nogués, Josep; Puy Llorens, Jaume; Baeyens, Willy; Gao, YueDetermining species, concentrations, and physicochemical parameters in natural waters is key to improve our understanding of the functioning of these ecosystems. Diffusive Gradients in Thin-films (DGT) devices with different thicknesses of the resin or of the diffusive disc can be used to collect independent information on relevant parameters. In particular, DGT devices with a stack of two resin discs offer a simple way to determine dissociation rate constants of metal complexes from the accumulation of the target metal in the back resin disc. In this work, simple approximate expressions for the determination of the dissociation rate constant are reported and applied to a model Ni nitrilotriacetic complex as well as to Zn complexes in the Mediterranean Osor stream. Once the physicochemical parameters are known, one can plot the labile fraction of the metal complexes in terms of the thickness of the diffusion domain. These plots reveal a strong dependence on the nature of complexes as well as on the characteristics of the diffusion domain, and they are of high interest as predictors of availability to biota whose uptake is limited by diffusion.
- ItemOpen AccessBioinspired models for assessing the importance of transhumance and transboundary management in the conservation of European avian scavengers(Elsevier, 2018) Margalida, Antoni; Oliva-Vidal, Pilar; Llamas, Alfonso; Colomer, M. Àngels (Maria Àngels)The assessment of temporal and spatial availability of food resources is an important prerequisite in developing improved management tools for effective conservation action. It is especially useful in the conservation of avian scavengers inhabiting regions where livestock move on a regular basis (transhumance). Important management decisions can be taken on the basis of theoretical analyses that need to be regularly checked. In this case study, we consider models of Griffon vulture Gyps fulvus, Egyptian vulture Neophron percnopterus and bearded vulture Gypaetus barbatus populations in a part of Spain with one of the highest densities of scavenging birds, and where traditional farming practices remain. We applied bioinspired Population Dynamic P System models (PDP) to assess these species' population trends against the distribution, quantity and availability of carrion for food. We show asymmetries in the availability of food resources, which are substantially higher in summer due to transhumant movements. In the study area, a lack of food resources in winter leads to a seasonal reduction in food supplies to levels unable to meet the energetic requirements of the most abundant vulture species, the Griffon vulture. Our results suggest that regardless of active management (e.g. supplementary feeding sites) and the birds’ use of other potential food resources not included in the model, Griffon vultures are able to find important alternative food resources in more remote areas. We show the importance of variations at spatio-temporal scales in the objective forecasting of population trends, and in the correct application of management actions. Because of the importance of robust assessments for management applications, we discuss the advantages and limitations of ecological modelling for avian scavengers, highlighting the importance of transhumance processes and transboundary approaches.